Ministry of Education and Science of the Russian Federation

Saratov State Technical University

A.S. Denisov

Basics of performance technical Systems

Textbook

Associated UMOs of the universities of the Russian Federation by education

in the field of transport trucks

and transport and technological complexes

as a textbook for students of universities,

students in specialties

"Service of transport and technological

machinery and equipment (automotive

transport) "and" Cars and automotive

economy »Preparation Directions

"Operation of land transport

and transport equipment»

Saratov 2011.

UDC 629.113.004.67

Reviewers:

Department "Reliability and repair of cars"

Saratov State Agrarian University

them. N.I. Vavilova

Doctor of Technical Sciences, Professor

B.P. Zagodsky

Denisov A.S.

D 34 The basis of the performance of technical systems: textbook / A.S. Denisov. - Saratov: Sarat. State tehn University, 2011. - 334 p.

ISBN 978-5-7433-2105-6

The textbook provides data on the content of various technical systems. Analyzed elements of mechanics for the destruction of machine parts. The patterns of wear, fatigue destruction, corrosion, plastic deformation of parts during operation are substantiated. The methods of justifying the standards for ensuring the operation of machines and adjust them by operating conditions are considered. The patterns of satisfaction of service needs using the provisions of the theory of mass maintenance are substantiated.

The textbook is intended for students of the specialties "Transport and technological machines and equipment (road transport) "and" Cars and Automotive Economy ", and can also be used by workers in car service, auto repair and road enterprises.

UDC 629.113.004.67

© Saratov State

ISBN 978-5-7433-2105-6 Technical University, 2011

Denisov Alexander Sergeevich -doctor of Technical Sciences, Professor, Head of the Department of "Cars and Automotive" Saratov State Technical University.

In 2001, he received the scientist of the professor, in 2004 he was elected by the Academician of the Transport Academy of Russia.

Scientific activity Denisova A.S. devoted to the development of theoretical foundations technical exploitation Car, justifying the system of patterns of changes in the technical condition and indicators of the efficiency of car use during operation in various conditions. They have developed new methods for diagnosing the technical condition of car elements, control and management of their work modes. Theoretical developments and experimental studies of Denisova A.S. They contributed to the grounds and approval of the new scientific direction in the science on the reliability of machines, which is now known as the "theory of formation of resource-saving operational and repair cycles of machines."

Denisov A.S. It has more than 400 printed works, including: 16 monographs and textbooks, 20 patents, 75 articles in central journals. Under his scientific leadership, 3 doctoral and 21 candidatesses are prepared and successfully defended. In Saratov State Technical University Denisov A.S. Created a scientific school that develops the theory of service of the machine, well-known in the country and abroad. Awarded the honorary signs of the "Honorary Worker of Transport of Russia", "Honorary Worker of Higher Professional Education of the Russian Federation."

Introduction

Technique (from the Greek word Techne - art, skill) is a combination of human activities created for the implementation of the processes of production and satisfying the non-productive needs of society. The technique includes all the variety of created complexes and products, machinery and mechanisms, industrial buildings and structures, devices and aggregates, tools and communications, devices and devices.

The term "system" (from Greek Systema - a whole composed of parts) has a wide range of values. In science and technology, the system is a plurality of elements, concepts, norms with relations and connections between them forming some integrity. Under the element of the system, one understands part of it intended to perform certain functions and indivisible to parts at this level of consideration.

In this paper, we consider part of the technical systems - transport and technological machines. The focus is on cars and technological auto service equipment. For the entire service life of the cost of ensuring their performance at 5 - 8 times higher than the production costs. The basis for reducing these costs is the patterns of changing the technical condition of the machines during operation. Up to 25% of the refusals of technical systems are caused by service personnel errors, and up to 90% of accidents in transport, in various power systems are the result of erroneous actions of people.

The actions of people are usually substantiated by the decisions taken, which are selected from several alternatives based on collected and analyzed information. Analysis of information is made on the basis of knowledge of processes occurring when using technical systems. Therefore, in the preparation of specialists, it is necessary to study the patterns of changes in the technical condition of machines during operation and methods to ensure their performance.

This work was prepared in accordance with the educational standard for the discipline "Fundamentals of the performance of technical systems" for a specialty 23100 - service of transport and technological machines and equipment (road transport). It can also be used by students of the specialty "Cars and Automotive Services" when studying the discipline "Technical operation of cars", specialty 311300 "Mechanization agriculture"Under the discipline" Technical operation of motor vehicles ".

Basic concepts in the field of performance of technical systems

Transcript.

1 Federal Agency for Education Syktyvkarian Forest Institute Branch of the State Educational Institution of Higher Professional Education "St. Petersburg State Forestry Academy named after S. M. Kirov" Department of Car and Automotive Fundamental Fundamental Technical Systems Methodological manual for disciplines "Fundamentals of technical systems", " Technical operation of cars "," Basics of the theory of reliability and diagnostics "for students of specialties" Service of transport and technological machines and equipment ", 9060" Cars and automotive "all forms of training Edition Second, recycled Syktyvkar 007

2 UDC 69.3 O-75 discussed and recommended for pressing the Council of the Field Transport Faculty of the Syktyvkar Forest Institute on May 7, 007 compilers: Art. Lecturer R. V. Abimov, Art. Lecturer P. A. Malashchuk Reviewers: V. A. Likhanov, Doctor of Technical Sciences, Professor, Academician of the Russian Academy of Transport (Vyatka State Agricultural Academy); A. F. Kulminsky, Candidate of Technical Sciences, Associate Professor (Syktyvkar Forest Institute) Fundamentals of Technical Systems: O-75 Method. Manual on the disciplines "Fundamentals of technical systems", "Technical operation of cars", "Basics of the theory of reliability and diagnostics" for studies. Special "Service of Transport and Technological Machines and Equipment", 9060 "Cars and Automotive Economy" of All Forms / Sost. R. V. Abimov, P. A. Malashuk; Skut. Lesn. In-t. Ed. Second, recreation. Syktyvkar: Sing, p. The methodological manual is intended for practical training on the disciplines "Fundamentals of the performance of technical systems", "Technical operation of cars", "Fundamentals of the theory of reliability and diagnostics" and for performing tests of students of correspondence formation. The manual contains the basic concepts on the theory of reliability, the basic laws of the distribution of random variables in relation to road transport, collecting and processing materials for reliability, general guidelines for the choice of task options. The tasks reflect the issues of building structural schemes, test planning and the basic laws of the distribution of random variables are taken into account. The list of recommended literature is given. The first edition was published in 004. UDC 69.3 R. V. Abimov, P. A. Malashchuk, compilation, 004, 007 SELI, 004, 007

3 Introduction During the period of operation of complex technical systems, one of the main tasks is to determine their performance, i.e. the ability to perform functions assigned to them. This ability to largely depends on the reliability of products laid by the design period implemented in the manufacture and supported during operation. System reliability techniques covers various aspects of engineering activities. Thanks to the engineering calculations of the reliability of technical systems, it is guaranteed to maintain uninterrupted electricity supply, a safe movement of transport, etc. To properly understand the problems of ensuring the reliability of systems, it is necessary to know the foundations of the classical theory of reliability. The methodological manual provides basic concepts and definitions of reliability theory. The main qualitative indicators of reliability, such as the probability of trouble-free operation, frequency, failure intensity, the average operation before the failure, failure flow parameter. Due to the fact that in the practice of exploiting complex technical systems in most cases, it is necessary to deal with probabilistic processes, the most frequently used laws for the distribution of random variables that determine reliability indicators are considered separately. The reliability indicators of most technical systems and their elements can only be determined by test results. In a methodological manual, a separate part is devoted to a methodology for collecting, processing and analyzing statistical data on the reliability of technical systems and their elements. To secure the material, the test work consists of answers to questions on the theory of reliability and solving a number of tasks. 3.

four . Car Reliability .. Terminology for Reliability Reliability This property of machines perform the specified functions, maintaining its operational performance in the specified limits during the required operation. The theory of reliability is the science that studies the patterns of failures, as well as ways to prevent and eliminate them to obtain the maximum efficiency of technical systems. The reliability of the machine is determined by reliability, maintainability, durability and persistence. For cars, as for other multiple operation machines, a discrete process of operation is characteristic. When operating failures. The time spent during their search and the elimination time during which the machine is idle, after which the operation resumes. Performance of the product condition in which it is capable of performing specified functions with parameters whose values \u200b\u200bare set by technical documentation. In the event that the product, although it can perform its main functions, but does not meet all the requirements of technical documentation (for example, the car's wing) is operational, but faulty. Undetyability This property of the machine to maintain performance for some time without forced breaks. Depending on the type and purpose of the machine, the operating machine to failure is measured in hours, mileage kilometers, cycles, etc. Refusal is such a malfunction, without the elimination of which the machine cannot perform specified functions with parameters set by the requirements of technical documentation. However, not any malfunction can be a refusal. There are such failures that can be eliminated with the next maintenance or repair. For example, when operating machines, the machines are inevitable to loosen the normal tightening of fastening parts, violation proper adjustment nodes, aggregates, control drives, protective coatings, etc. If there are not 4 times in a timely manner

5 eliminate, it will refuse to work machines and labor-intensive repair. Failures are classified: on the effect on the performance of the product: causing a malfunction (reduced tire pressure); causing failure (opening of the generator drive belt); on the source of the occurrence: constructive (due to errors in design); production (due to violation of the manufacturing or repair process); operational (use of substandard operational materials); Due to the links with other elements: dependent, due to the refusal or malfunction of other elements (zadira of the cylinder mirror due to breakdown of the piston finger); independent, not caused by the refusal of other elements (crossing the tire); According to the nature (patterns) of the emergence and possibility of forecasting: gradual, resulting from accumulation in the details of the wear machine and fatigue damage; Sudden, emerging unexpectedly and related, mainly with breakdowns due to overloads, manufacturing defects, material. The moment of failure is random, independent of the operation (blowing fuses, breakdowns of the parts of the chassis at the end of the obstacle); By influencing the loss of working time: eliminated without loss of working time, i.e., for maintenance or inoperative (intersdency); Estimated with loss of working time. Signs of objects failures are called direct or indirect effects on the organs of the observer of phenomena characteristic of the inoperative state of the object (the fall in the oil pressure, the appearance of the chapels, the change in the temperature regime, etc.). five

6 The nature of failure (damage) is concrete changes in the object associated with the occurrence of failure (wire break, the deformation of the part, etc.). The consequences of refusals include phenomena, processes and events arising after refusal and in direct causal connection with it (engine stop forced simple technical reasons). In addition to the general classification of failures, one for all technical systems, for individual groups of machines, depending on their purpose and the nature of the work, an additional classification of failures are applied to the complexity of their elimination. All elimination failures are combined into three groups, while taking into account factors such as a way to eliminate, the need to disassemble and the complexity of elimination of failures. Durability This property of the machine is to maintain a healthy state to the limit with the necessary interruptions for maintenance and repairs. A quantitative estimate of durability is the full service life of the machine from the beginning of operation before write-off. Design new machines should ensure that the timing of the physical wear service does not exceed moral aging. The durability of the machines is laid during their design and design, ensured in the production process and is supported during operation. Thus, the durability is influenced by structural, technological and operational factors, which, according to the degree of exposure, allow you to classify durability into three types: the required, achieved and valid. The required durability is set in terms of design and is determined by the achieved level of development in this industry. The achieved durability is determined by the perfection of design calculations and technological processes of manufacture. Actual durability characterizes the actual side of the use of the machine by the consumer. In most cases, the required durability is more reached, and the last more valid. At the same time not rare 6

7 cases when the actual durability of the machines exceeds the achieved. For example, when the mileage is normal to overhaul (CR), equal to 0 thousand km, some drivers at the skillful operation of the vehicle reached a mileage without overhaul of 400 thousand km and more. The actual durability is divided into physical, moral and technical and economic. Physical durability is determined by the physical wear of the part, the node, the machines to their limit state. For aggregates, the physical wear of the base parts is determined (the engine has a cylinder block, the gearbox Carter, etc.). Moral durability characterizes the service life, beyond which the use of this machine becomes economically inappropriate due to the appearance of more productive new machines. Technical and economic durability determines the service life, beyond which the repair of the machine becomes economically inexpedient. The main indicators of the durability of the machines are the technical resource and service life. Technical resource There is an object work before starting to operate or resume it after medium or overhaul before the marginal state. Service life Calendar duration of operation of the object from its start or resumption after medium or overhaul before the marginal state. Maintainability This property of the machine, which consists in its adaptability to the warning, detection, as well as to eliminate failures and malfunctions to carry out maintenance and repairs. The main task of ensuring maintainability of machines is the achievement of optimal costs for their maintenance (MA) and repair with the greatest efficiency of use. The continuity of technological processes and repair characterizes the possibility of using typical technological processes and repair as the machine as a whole and its component parts. Ergonomic characteristics are used to assess the convenience of performing all operations and repair and should exclude OPE- 7

8 wages requiring the finding of the performer for a long time in an uncomfortable posture. The safety of implementation and repair is provided with technically good equipment, compliance with the rules of norms and safety regulations. The above properties in the aggregate determine the level of maintainability of the object and have a significant impact on the duration of repairs and maintenance. The fitness of the machine to and repair depends on: the number of parts and components requiring systematic maintenance; service periodicity; availability of service points and ease of operation; ways to connect parts, independent removal capabilities, presence for capture, ease of disassembly and assembly; From the unification of parts and operational materials both within one car model and between different models Car etc. Factors affecting maintainability can be combined into two main groups: settlement and design and operational. The settlement and design factors include the complexity of the design, interchangeability, convenience of accessing nodes and details without the need to remove near nodes and parts, ease of replacement of parts, reliability of the design. Operational factors are associated with the possibilities of the person operator, the operating machine and with the surrounding conditions in which these machines work. These factors include experience, skill, qualifications of service personnel, as well as technology and methods for organizing production and repair. Pasteability This property of the machine is to withstand the negative impact of storage conditions and transportation on its reliability and durability. Since the work is the main state of the object, the influence of storage and transportation on the subsequent behavior of the object in the operating mode is of particular importance. eight

9 distinguish the persistence of an object before commissioning and during operation (during breaks in operation). In the latter case, the period of continuity is included in the service life of the object. A gamma percentage and average duration of continuity is used to assess the persistence. The gamma percentage of continuity is the term of continuity, which will be achieved by an object with a given probability of gamma percent. The average period of persistence is called the mathematical expectation of the period of persistence ... Quantitative indicators of reliability of machines When solving practical problems associated with the reliability of machines, high-quality assessment is not enough. For quantitative assessment and comparison of reliability different machines It is necessary to enter the appropriate criteria. Such applicable criteria include: the probability of failure and the likelihood of trouble-free operation during the specified operation time (run); Failure frequency (failure density) for non-processed products; failure intensity for non-processed products; failure streams; average time (mileage) between failures; Resource, gamma percentage resource, etc. .... Characteristics of random variables Random value This is a value that, as a result of observations, can take various values, and in advance what (for example, working on failure, labor-intensity of repair, duration of downtime in repair, time of trouble-free operation, the number of failures to some time, etc.). nine

10 due to the fact that the value of a random variable is unknown in advance, the probability is used to evaluate it (the probability that a random value will be in the range of possible values) or frequency (the relative number of cases of the occurrence of a random variable in the specified interval). Random value can be described through the arithmetic meaning, mathematical expectation, fashion, median, random variable, dispersion, rms deviation and variation coefficient. The average arithmetic value is particular from dividing the amount of the values \u200b\u200bof the random values \u200b\u200bobtained from the experiments to the number of the terms of this amount, i.e., by the number of experiments N n n n, () where the arithmetic average of a random variable; N number of experiments; x, x, x n Separate values \u200b\u200bof random variance. Mathematical expectation The amount of products of all possible values \u200b\u200bof the random variable on the likelihood of these values \u200b\u200b(P): X N P. () Between the average arithmetic value and the mathematical expectation of the random value, there is the following connection with a large number of observations. The average arithmetic value of a random variable is approaching its mathematical expectation. The mod is the most likely value of its value, i.e. the value that matches the highest frequency. Graphically mode corresponds to the greatest ordinate. The median of a random value is its meaning for which the random value will be equally or less median. The geometrically median determines the abscissa of the point, the ordinate of which divides the area, limited curve,

11 division in half. For symmetric modal distributions, the arithmetic average, fashion and median coincide. The scope of dispersion of a random variable is the difference between the maximum and minimum values \u200b\u200bobtained by the test: R MA Mn. (3) The dispersion is one of the main characteristics of the dispersion of a random variable near its average arithmetic value. It is determined by the formula: D n n (). (4) The dispersion has the dimension of the square of the random variable, so it is not always convenient to use it. The average quadratic deviation is also a measure of dispersion and is equal to the root square from the dispersion. Σ n n (). (5) Since the average quadratic deviation has the dimension of a random variable, to use it more convenient than the dispersion. The average quadratic deviation is also called the standard, the main error or the main deviation. The average quadratic deviation, expressed in the shares of the average arithmetic, is called the coefficient of variation. Σ Σ ν or ν 00%. (6) the introduction of the coefficient of variation is necessary to compare the scattering of values \u200b\u200bhaving different dimension. For this purpose, the average quadratic deviation is unsuitable, as it has the dimension of a random variable.

12 ... The probability of trouble-free operation of the machine believe that the machines work correctly if under certain operating conditions they retain performance for a given operation. Sometimes this indicator is called the reliability ratio, which evaluates the likelihood of trouble-free operation for the period of operation or at a specified operating interval of the machine under specified operating conditions. If the probability of trouble-free operation of the vehicle during the run of L km is equal to P () 0.95, then from a large number of cars of this brand, about 5% lose its performance earlier than through km run. When observed in the conditions of operation of the N-GO number of cars for mileage (thousand km), it is possible to approximately determine the probability of trouble-free operation P (), as the ratio of the number of properly operating machines to the total number of machines under observation throughout the operation, i.e. p () N n () nn n / n; (7) where n is the total number of cars; N () the number of working machines to work out; n Number of refused machines; The value of the interval under consideration. To determine the true value P (), you need to move to the P () n / () n n n Lm at 0, N 0. N probability P (), calculated by formula (7), is called a statistical assessment of the probability of trouble-free operation. Failures and reliability These are the events opposite and inconsistencies, as they cannot appear simultaneously in this machine. Hence the sum of the probability of trouble-free operation P () and the probability of failure f () is equal to one, i.e.

13 p () + f (); P (0); P () 0; F (0) 0; F () ... 3. The frequency of failures (density of failures) of the frequency of failures is called the ratio of the number of refused products per unit of time to the initial number of under observation under the condition that the refused products are not restored and not replaced with new ones, i.e. f () () n, (8) n where n () the number of failures in the examination interval under consideration; N Total number of products under observation; The value of the interval under consideration. In this case, n () can be expressed as: n () n () n (+), (9) where N () the number of working products for the operation was working; N (+) The number of working products for the development of +. Since the probability of trouble-free operation of products for moments and + is expressed: n () () p; P () n (+) n +; N n () np (); N () np (+) +, then n () n (0) 3

14 Substituting the value of n (t) from (0) to (8), we obtain: f () (+) p () P. Turning to the limit, we obtain: f () since p () f (), then (+ ) P () dp () p lm at 0. d [f ()] df (); () d f () d d () df f. () D Therefore, the frequency of failures is sometimes referred to as the differential law distribution of the output time of products. Integrating the expression (), we obtain that the probability of refusal is: f () f () d 0 in size F () can be judged by the number of products that may fail at any occasion range. The probability of failure (Fig.) In the range of operations, it will be: f () f () f () d f () d f () d. 0 0 Since the probability of failure F () is equal to one, then: 0 (). F d. four

15 f () rice .. The likelihood of failure in a given interval of operations..4. The intensity of failures under the intensity of failures understand the ratio of the number of refused products per unit of time to the average number of working nonsense during this period of time, provided that the refused products are not restored and not replaced with new ones. From these testing, the failure intensity can be calculated by the formula: λ () N n n c () (), () where N () the number of refused products during from to +; The examination interval under consideration (KM, H, etc.); N cp () Average number of trouble-free working products. The average number of reliability of working products: () + n (+) n NSR (), (3) where N () is the number of non-profitable products at the beginning of the operating interval under consideration; N (+) The number of trouble-free products at the end of the operating interval. five

16 The number of failures in the examination interval under consideration is expressed: n () n () n (+) [n (+) n ()] [n (+) p ()]. (4) Substituting the values \u200b\u200bof N cp () and n () from (3) and (4) in (), we obtain: λ () nn [p (+) p ()] [p (+) + p ()] [P (+) p ()] [p (+) + p ()]. Turning to the limit at 0, we obtain as f (), then: () λ () [p ()]. (5) p () () f λ. P () After the integration of formula (5) from 0 to receiving: p () e () λ d. 0 at λ () const The probability of trouble-free operation of products is: P λ () E ... 5. Fault stream parameter At the time of operation, the failure stream parameter can be determined by the formula: 6 () DMCR Ω (). D.

17 The lapse of the D M is small, and therefore, during the ordinary failure stream in each machine during this gap, no more than one failure may occur. Therefore, the increment of an average failure number can be defined as the ratio of the number of calibrations of DM machines to the total number of N machines under observation: Dm Dm n () DQ CP, where DQ is the probability of refusal for the period d. From here we obtain: Dm DQ Ω (), nd d, i.e. The failure stream parameter is equal to the likelihood of a failure of the unit at the time. If instead of D take a finite period of time and via M () we denote the total number of failures in the machines at this time interval, we obtain a statistical estimate of the failure stream parameter: () m ω (), n where m () is determined by the formula: n where m (+) N (+); M () Mn n () m (+) M () Changing the failure stream parameter for the time for most repaired products proceeds, as shown in fig. On the site there is a rapid increase in the failure stream (the curve goes up), which is associated with the output from Building parts and 7 Total failures at the time of time Total failures at time.

18 nodes having defects manufacturing and assembly. Over time, the details are developed, and the sudden failures disappear (the curve goes down). Therefore, this area is called a parting site. On the section of failure streams can be considered permanent. This is a plot of normal operation of the machine. Here they occur mainly to sudden failures, and the wear parts are changed during maintenance and planned-warning repairs. On the portion 3 Ω () increases sharply due to the wear of most nodes and parts, as well as the basic parts of the machine. During this period, the car usually goes to overhaul. The longest and essential plot of the machine is. Here, the failure stream parameter remains almost at the same level with the constancy of the operating conditions of the machine. For a car, this means driving in relatively permanent road conditions. ω () 3 rice .. change the flow of failures if on the portion of the failure stream parameter, which is an average of failures per unit of operation, permanent (ω () const), then the average failure number for any period of operation of the machine on this site τ will : M cf (τ) ω () τ or ω () m cp (τ). τ 8.

19 Working on a refusal for any period τ on-site of work is equal to: τ const. M τ ω (τ) cf is consequently, the failure of the failure and failure flow parameter, subject to its constancy, are reverse values. The stream of failure of the machine can be viewed as the amount of failure threads separate nodes and details. If the machine contains k refusing elements and for a sufficiently large period of operation of working on the failure of each element is, 3, k, then the average number of failures of each element for this time will be: M cf (), m (), ..., m () Wed Srk. Obviously, the average of the machine failures for this time will be equal to the sum of the average number of failures of its elements: M () m () + m () + ... m (). + Wed Wed Wed Srk Differentiating this expression on troubleshooting, we obtain: DMCR () DMSR () DMCR () DMSR K () DDDD or ω () ω () + ω () + + ω k (), i.e. parameter The machine failure stream is equal to the amount of flow parameters of the components of its elements. If the failure flow parameter is permanent, then such a stream is called stationary. This property has the second section of the failure flow curve. Knowledge of the reliability of the machine allows you to produce various calculations, including calculations of the need for spare parts. The number of spare parts N of RS for the time will be equal to: 9 k

20 N valum ω () N. Given that ω () function, for a sufficiently large operation in the range from T to T, we obtain: n zh n ω (y) dy. In fig. 3 shows the dependence of the change in the parameters of the KAMAZ-740 engine failure failure in operating conditions in the conditions of Moscow, in relation to cars, the work of which is expressed by a mileage kilometer. ω (t) l (mileage), thousand km Fig. 3. Change the motor failure flux under operation 0

21. The laws of the distribution of random variables that determine the indicators of the reliability of machines and their details based on the methods of the theory of probability, it is possible to establish patterns at machines failures. At the same time, experienced data obtained from the results of tests or observations of the operation of machines are used. In solving most practical problems of operation of technical systems, probabilistic mathematical models (i.e., models representing a mathematical description of the results of a probabilistic experiment) are represented in an integrally differential form and are called theoretical laws of the distribution of a random value. For mathematical description Experimental results One of theoretical distribution laws is not enough to take into account only the similarity of experimental and theoretical graphs and numerical characteristics of the experiment (coefficient of variation V). It is necessary to have the concept of basic principles and physical laws of the formation of probabilistic mathematical models. On this basis, it is necessary to carry out a logical analysis of causal relationships between the main factors that affect the course of the process under study and its indicators. The probabilistic mathematical model (distribution law) of a random variable is a correspondence between the possible values \u200b\u200band their probabilities of P () in which each possible value of the random variable is delivered in compliance with a certain value of its probability P (). When operating machines, the following distribution laws are most characteristic: Normal; Logarithmically normal; The law of the distribution of Waibulla; Exponential (indicative), Poisson distribution law.

22 .. The exponential law of distribution to the course of many road transport processes and, consequently, the formation of their indicators of both random variables is influenced by a relatively large number of independent (or weakly dependent) elementary factors (terms), each of which is separately an insignificant effect compared to With the total influence of all others. Normal distribution is very convenient for the mathematical description of the sum of random variables. For example, the operation (mileage) to carry out that it consists of several (ten or more) interchangeable runs that differ from each other. However, they are comparable, i.e. the influence of one replaceable run on the total developing is insignificant. The complexity (duration) of operations of operations (control, fasteners, lubricants, etc.) is made up of the amount of labor intensity of several (8 0 or more) mutually independent transition elements and each of the components is quite small in relation to the amount. Normal law is also well consistent with the results of an experiment on the evaluation of the parameters characterizing the technical condition of the part, a node, an aggregate and a car as a whole, as well as their resources and developments (runs) before the appearance of the first failure. These parameters include: intensity (speed of wear); medium wear of parts; change in many diagnostic parameters; The content of mechanical impurities in oils, etc. For a normal distribution law in practical tasks of technical operation of cars, the coefficient of variation V 0.4. The mathematical model in differential form (i.e., the differential function of the distribution) is: f σ () e () σ π, (6) in the integral form () σ f () e d. (7) Σ π

23 The law is two-parameter. The parameter mathematical expectation characterizes the position of the scattering center relative to the beginning of the reference, and the parameter σ characterizes the stretchability of the distribution along the abscissa axis. The characteristic graphs f () and f () are shown in Fig. 4. F () f (), 0 0.5-3σ -σ -σ + σ + σ + 3σ 0 a) b) Fig. 4. Graphs of theoretical curves of differential (A) and integral (b) functions of the distribution of a normal law from Fig. 4 It can be seen that the F () graph is symmetric relatively and has a bell-shaped appearance. The entire area limited by the graph and axis of the abscissa, to the right and left by it is divided by segments equal to σ, σ, 3 σ into three parts and is: 34, 4 and%. Over the limits of three SIGM, only 0.7% of all values \u200b\u200bof a random variable. Therefore, normal law is often called the "three SIGM" law. Calculations of values \u200b\u200bf () and f () are conveniently produced if expressions (6), (7) convert to more simplicity. This is done in such a way that the origin of the coordinates to move to the symmetry axis, i.e. to the point, to be present in relative units, namely in parts proportional to the average quadratic deviation. To do this, it is necessary to replace the variable value of another, normalized, i.e., expressed in units of medium quadratic deviation 3

24 z σ, (8) and the value of the average quadratic deviation to put equal, i.e. σ. Then in the new coordinates we obtain the so-called centered and normalized function, the density of the distribution of which is determined: z φ (z) e. (9) π The values \u200b\u200bof this feature are shown in the ad. Integral normalized function will take the form: (dz. (0) π zzz f0 z) φ (z) DZ E This function is also protablished, and it is convenient to use it at the calculations (adj.) . The values \u200b\u200bof the function f 0 (z), which are given in the adj., Are given at z 0. If the value z is negative, then it is necessary to use the formula F 0 (0 Z for the function φ (z). The ratio z) f () is valid. () φ (z) φ (z). () The reverse transition from the centered and normalized functions to the initial is made according to the formulas: f φ (z) σ (), (3) f) f (z). (4) (0 4

25 In addition, using the normalized Laplace function (adj. 3) zz f (z) e dz, (5) π 0 integral function can be written in the form () F. F + (6) σ theoretical probability P () of random variable , distributed normally, in the interval [a< < b ] с помощью нормированной (табличной) функции Лапласа Ф(z) определяется по формуле b Φ a P(a < < b) Φ, (7) σ σ где a, b соответственно нижняя и верхняя граница интервала. В расчетах наименьшее значение z полагают равным, а наибольшее +. Это означает, что при расчете Р() за начало первого интервала, принимают, а за конец последнего +. Значение Ф(). Теоретические значения интегральной функции распределения можно рассчитывать как сумму накопленных теоретических вероятностей P) каждом интервале k. В первом интервале F () P(), (во втором F () P() + P() и т. д., т. е. k) P(F(). (8) Теоретические значения дифференциальной функции распределения f () можно также рассчитать приближенным методом 5

26 p () f (). (9) The failure intensity for the normal distribution law is determined by: () () F λ (x). (30) P task. Let the explosion of the spring of the car gas- 30 obeys the normal law with the parameters of 70 thousand km and σ 0 thousand km. It is required to determine the characteristics of the reliability of the springs for the mileage of X 50 thousand km. Decision. The probability of the refrigeration is determined through the normalized function of the normal distribution, for which it first define the normalized deviation: z. Σ With regard to the fact that F 0 (z) F0 (z) F0 () 0.84 0, 6, the probability of refusal is f () f0 (z) 0, 6, or 6%. The probability of trouble-free operation: frequency of failures: p () f () 0.6 0.84, or 84%. φ (z) f () φ φ; Σ Σ Σ 0 0, taking into account the fact that φ (z) φ (z) φ () 0, 40, the frequency of refusals of the spring F () 0.0. f () 0.0 Intensity of failures: λ () 0, 044. p () 0.84 6

27 When solving practical reliability tasks, it is often necessary to determine the operation of the machine for the specified values \u200b\u200bof the probability of failure or trouble-free operation. Similar tasks are easier to solve using the so-called quantile table. Quantiota is the value of the argument function corresponding to the specified value of the probability function; Denote the function of the probability of refusal under normal law P F0 P; Σ p arg f 0 (p) u p. Σ + Σ. (3) P U p Expression (3) Determines the operation P of the machine for a given value of the probability of the failure of P. The operation corresponding to the specified value of the probability of trouble-free operation is expressed: x x σ u p p. In the quantile table of normal law (adj. 4), the values \u200b\u200bof the quantile U p for probabilities p\u003e 0.5 are given. For probabilities R.< 0,5 их можно определить из выражения: u u. p p ЗАДАЧА. Определить пробег рессоры автомобиля, при котором поломки составляют не более 0 %, если известно, что х 70 тыс. км и σ 0 тыс. км. Решение. Для Р 0,: u p 0, u p 0, u p 0,84. Для Р 0,8: u p 0,8 0,84. Для Р 0, берем квантиль u p 0,8 co знаком «минус». Таким образом, ресурс рессоры для вероятности отказа Р 0, определится из выражения: σ u ,84 53,6 тыс. км. p 0, p 0,8 7

28 .. Logarithmically normal distribution The logarithmically normal distribution is formed if the proceeding of the under study and its result affects a relatively large number of random and interconnected factors whose intensity depends on the reached random value of the state. This so-called proportional effect model considers some random value having the initial state 0 and the final limit state n. The change in the random variable occurs in such a way that (), (3) ± ε h where ε the intensity of the change in random variables; h () Reaction function showing the nature of changing random variable. h We have: at () n (± ε) (± ε) (± ε) ... (± ε) π (± ε), 0 0 (33) where it is a mark of the product of random variables. Thus, the limit state: n n π (± ε). (34) 0 This follows that logarithmically normal law is convenient to use for a mathematical description of the distribution of random variables, which are the product of the source data. From the expression (34) it follows that N ln ln + ln (± ε). (35) N 0 Consequently, with a logarithmically normal law, the normal distribution is not the random amount itself, and its logarithm, as the sum of random isometric and non-independent Veli-8

29 Chin. A graphically, this condition is expressed in the extension of the right part of the differential function curve F () along the abscissa axis, i.e. the graph of the curve F () is asymmetric. In solving the practical tasks of the technical operation of the car, this law (at v 0.3 ... 0, 7) is used in describing the processes of fatigue destruction, corrosion, operations to the weakening of fastening compounds, changes in the gaps. And also in cases where the change in the technical occurs mainly due to wear of friction pairs or individual parts: overlays and drums of brake mechanisms, discs and friction linings of the clutch, etc. The mathematical model of the logarithmically normal distribution is: in differential form: in an integrated form: F f (ln) (ln) (ln a) σln e, (36) σ π ln (ln a) ln σln ED (ln), (37) Σ π ln where random value, the logarithm of which is distributed normally; a mathematical expectation of the logarithm of a random variable; Σ ln Average quadratic deviation of the logarithm of a random variable. The most characteristic curves of the differential function f (ln) are shown in Fig. 5. From fig. 5 It can be seen that graphs of functions are asymmetric, stretched along the abscissa axis, which is characterized by the parameters of the distribution form σ. LN 9.

30 f () Fig. 5. The characteristic graphs of the differential function of the logarithmically normal distribution for the logarithmically normal law of the replacement of variables is as follows: z ln a. (38) Σ ln z F 0 Z are determined by the same formulas and tables as for the normal law. To calculate the parameters, the values \u200b\u200bof natural logarithms Ln are calculated for the middle of the intervals, the statistical mathematical expectation A: the values \u200b\u200bof the functions φ (), () a k () Ln (39) m and the routine deviation of the logarithm under consideration of the random variable σ n k (ln a) ln n. (40) According to the tables of the probability densities of the normalized normal distribution, φ (z) is determined and the theoretical values \u200b\u200bof the differential distribution function by formula are determined by the formula: f () 30 φ (z). (4) ΣLN

31 Calculate the theoretical probabilities P () of the random variable in the range K: P () f (). (4) Theoretical values \u200b\u200bof the integral function of the distribution F () are calculated as the sum P () in each interval. The logarithmically normal distribution is asymmetrical relative to the average value of experimental data for it. Therefore, the value of the assessment of the mathematical expectation () of this distribution does not coincide with the estimate calculated by the formulas for normal distribution. In this regard, the assessment of the mathematical expectation of M () and the average quadratic deviation σ is recommended to be determined by the formulas: () σln A + M E, (43) σ (σ) M () (E) LN M. (44) in this way the generalization and distribution of the results of the experiment is not the entire general population using mathematical model The logarithmically normal distribution it is necessary to apply estimates of parameters M () and M (σ). The logarithmically normally subordinate to the failures of the following parts of the car: slave clutch discs; front wheel bearings; the frequency of weakening threaded connections in the nodes; fatigue destruction of parts with bench tests. 3.

32 task. With bench tests of the car, it is established that the number of cycles before destruction is subject to logarithmically normal law. Determine the resource of parts from the condition of the absence of 5 destruction p () 0.9999, if: a σ 0 cycles, n k σln (ln a) n, σ σ (ln ln) 0, 38. N n solution. Table (adj. 4) Find for P () 0.9999 Uour 3,090. Substituting the values \u200b\u200bof U p, and σ in the formula, we obtain: 5 0 EP 3.09 0, () cycles .. 3. The Law of the Waibulla distribution The law of the Waibulla distribution is manifested in the model of the so-called "weak link". If the system consists of groups of independent elements, the failure of each of which leads to the failure of the entire system, then in such a model, the time distribution (or run) is considered to achieve the limit state of the system as the distribution of the corresponding minimum values \u200b\u200bof individual elements: C Mn (;; ...; n). An example of using Weibulla's law is the distribution of a resource or intensity of changes in the parameter of the technical condition of products, mechanisms, parts that consist of several elements constituting the chain. For example, a rolling bearing resource is limited to one of the elements: a ball or a roller, a specific separator section, etc., and is described by the specified distribution. According to a similar scheme, the limit state of thermal gaps of the valve mechanism occurs. Many products (aggregates, knots, car systems) When analyzing the refusal model, can be considered as consisting of several elements (sections). These are gaskets, seals, hoses, pipelines, drive belts, etc. The destruction of these products occurs in different places and with different developments (run), but the product resource as a whole is determined by its weaker site. 3.

33 The law of Waibulla distribution is very flexible to assess the reliability of cars. With it, it is possible to simulate the processes of sudden failures (when the parameter of the shape of the distribution B is close to one, i.e. b) and failures due to wear (b, 5), and then when the reasons that cause both of these refusals . For example, the refusal associated with fatigue destruction may be caused by the joint action of both factors. The presence, hardening cracks or the cut on the surface of the parts that are manufacturing defects, usually causes fatigue destruction. If the initial crack or incision is large enough, they themselves can cause a breakdown of the part with a sudden application of a significant load. This will be a case of a typical sudden refusal. The Waibulla distribution also describes the gradual failures of the parts and components of the car caused by the aging of the material as a whole. For example, the failure of the body of passenger cars due to corrosion. For the distribution of Weibulla in solving the tasks of technical operation of cars, the value of the coefficient of variation is within v 0.35 0.8. The mathematical model of the Waibulla distribution is defined by two parameters, which causes a wide range of its use in practice. The differential function has the form: an integral function: f () F b A () A 33 B E B A B A, (45) E, (46) where b form is influenced by the shape of the distribution curves: at b< график функции f() обращен выпуклостью вниз, при b > convex up; And the scale parameter characterizes the stretchability of the distribution curves along the abscissa axis.

34 The most characteristic curves of the differential function are shown in Fig. 6. f () b b, 5 b b 0.5 Fig. 6. The characteristic curves of the differential function of the Waibulla distribution with B The Waibulla distribution is converted to an exponential (indicative) distribution, with B to the distribution of the relay, with B, 5 3.5, the Waibulla distribution is close to normal. This circumstance also explains the flexibility of this law and its widespread use. The calculation of the parameters of the mathematical model is made in the following sequence. Calculate the values \u200b\u200bof the natural logarithms LN for each sample value and determine the auxiliary values \u200b\u200bto estimate the parameters of the Waibulla A and B: Y N n Ln (). (47) Σ y n n (ln) y. (48) Determine the estimates of the parameters a and b: b π σ y 6, (49) 34

35 γ y b a e, (50) where π 6,855; γ 0.5776 Permanent Euler. The estimate of the parameter b obtained in this way at small values \u200b\u200bn (n< 0) значительно смещена. Для определения несмещенной оценки b) параметра b необходимо провести поправку) b M (N) b, (5) где M(N) поправочный коэффициент, значения которого приведены в табл.. Таблица. Коэффициенты несмещаемости M(N) параметра b распределения Вейбулла N M(N) 0,738 0,863 0,906 0,98 0,950 0,96 0,969 N M(N) 0,9 0,978 0,980 0,98 0,983 0,984 0,986 Во всех дальнейших расчетах необходимо использовать значение несмещенной оценки b). Вычисление теоретических вероятностей P () попадания в интервалы может производиться двумя способами:) по точной формуле: P b b βh βb β, (5) (< < β) H где β H и β соответственно, нижний и верхний пределы -го интервала по приближенной формуле (4). Распределение Вейбулла также B является асимметричным. Поэтому оценку математического ожидания M() для генеральной совокупности необходимо определять по формуле: B e M () a +. (53) b e 35

36 4. The exponential law of distribution The model of the formation of this law does not take into account the gradual change in the factors affecting the course of the under study. For example, a gradual change in the parameters of the technical condition of the car and its aggregates, nodes, parts as a result of wear, aging, etc., and considers the so-called unsalted elements and their failures. This law is used most often when describing the sudden failures, the operation (run) between the failures, the complexity of the current repairs, etc. For sudden failures, a hopping change in the technical condition indicator is characteristic. An example of a sudden refusal is damage or destruction in the case when the load instantly exceeds the strength of the object. At the same time, such an amount of energy is reported that its transformation into another type is accompanied by a sharp change in the physicochemical properties of the object (parts, nodes), causing a sharp drop in the strength of the object and failure. An example of an adverse combination of conditions causing, for example, a breakdown of the shaft, an action of a maximum peak load can be the action of the most weakened longitudinal fibers of the shaft in the load plane. When aging the car, the share of sudden failures increases. The conditions for the formation of the exponential law corresponds to the distribution of the mileage of nodes and aggregates between subsequent failures (except for the run from the beginning of commissioning and until the first refusal of this unit or node). The physical features of the formation of this model consist in the fact that under repair, in general, it is impossible to achieve full initial strength (reliability) of the unit or node. The infertion of the restoration of the technical condition after the repair is explained: only partial replacement precisely refused (faulty) details with a significant decrease in the reliability of the remaining (not refused) parts as a result of their wear, fatigue, violation of the content, tightness, etc.; use during repairs of replacement parts lower quality than in the manufacture of cars; lower production levels in comparison with their manufacturer caused by small-sector repair (inability to complex 36

37 Mechanization, applying specialized equipment, etc.). Therefore, the first refusals give the characteristic mainly of constructive reliability, as well as the quality of manufacturing and assembling of cars and their units, and subsequent characterize operational reliability, taking into account the existing level of organization and production and production and supply of spare parts. In this regard, it can be concluded that since the mileage of the unit or node after its repair (associated, as a rule, with disassembly and replacement of individual parts), the failures are manifested as sudden and their distribution in most cases is subject to the exponential law, although their physical nature is in The main joint manifestation of the wear and fatigue components. For exponential law in solving practical tasks of technical operation of vehicles V\u003e 0.8. The differential function has the form: F λ () λ E, (54) integral function: f (λ) e. (55) The timing of the differential function is shown in Fig. 7. F () Fig. 7. A characteristic curve of the differential function of exponential distribution 37

38 The distribution has one parameter λ, which is associated with an average value of a random variable by the relation: λ. (56) The unformed assessment is determined by the normal distribution formulas. Theoretical probabilities P () are determined by the approximate method according to formula (9), by the exact method according to the formula: P b λ λβh λβb (β< < β) e d e e. (57) H B β β H Одной из особенностей показательного закона является то, что значению случайной величины, равному математическому ожиданию, функция распределения (вероятность отказа) составляет F() 0,63, в то время как для нормального закона функция распределения равна F() 0,5. ЗАДАЧА. Пусть интенсивность отказов подшипников ОТКАЗ скольжения λ 0,005 const (табл.). Определить вероятность безотказной работы подшипника за пробег 0 тыс. км, если из- 000км вестно, что отказы подчиняются экспоненциальному закону. Решение. P λ 0,0050 () e e 0, 95. т. е. за 0 тыс. км можно ожидать, что откажут около 5 подшипников из 00. Надежность для любых других 0 тыс. км будет та же самая. Какова надежность подшипника за пробег 50 тыс. км? P λ 0,00550 () e e 0,

39 task. Using the condition of the above task, determine the likelihood of trouble-free operation in 0 thousand km between runs 50 and 60 thousand km and the trouble on failure. Decision. λ 0.005 () p () E E 0,95. The failure of the failure is: 00This. km. λ 0.005 Task 3. With what mileage will refuse 0 gears of gearboxes from 00, i.e. P () 0.9? Decision. 00 0.9 E; ln 0.9; 00LN 0.9 thousand km. 00 Table. Failure intensity, λ 0 6, / h, various mechanical elements Name of the gearbox element of the gearbox Bearings: ball roller bearings of sliding sealing elements: rotating progressively moving axis of shafts 39 Failure intensity, λ 0 6 Change limits 0, 0.36 0.0, 0 0,0, 0,005 0.4 0.5, 0, 0.9 0.5 0.6 The average value of 0.5 0.49, 0.45 0.435 0.405 0.35 Exponential law quite well describes the refusal of the following parameters: to the failure of many non-refined elements of radio-electronic equipment; there is an occasion between adjacent failures with the simplest failure stream (after the end of the running period); recovery time after failures, etc.

40. 5. Poisson distribution law The Poisson distribution law is widely used for the quantitative characteristics of a number of phenomena in the mass maintenance system: the flow of cars arriving at the service station, the flow of passengers arriving at the streets of urban transport, buyers flow, the flow of removal of subscribers on the PBX, etc. . This law expresses the distribution of the probabilities of a random value of the number of appearance of a certain event. The specified period of time, which can only be taken by integer values, i.e. m 0, 3, 4, etc., the likelihood of the number of events M 0, 3, ... For this period of time in the law of Poisson, it is determined by the formula: P (Ma) M (λ T) TM, A α λ EEM! M !, (58) where p (m, a) the likelihood of the appearance of the period T of a certain event is equal to m; m Random value representing the number of events for the segment of time considered; t segment of time during which some event is investigated; λ intensity or density event per unit time; α λt mathematical expectation of the number of events for the segment of time considered ..5 .. Calculation of the numerical characteristics of the Poisson law The sum of the probabilities of all events in any phenomenon is equal to, m a α i.e. e. M 0 m! The mathematical expectation of the number of events is: x a m m α α α (m) m e a e e a m 0!. 40.

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Ministry of Education and Science of the Russian Federation

Federal State Budgetary Educational

Establishment of higher education

"Samara State Technical University"

Faculty of gravity

Department "Transport processes and technological complexes"

Course project

according to academic discipline

"Basics of operability of technical systems"

Performed:

N.D. Tsygankov

Checked:

OM Batishcheva

Samara 2017.

ESSAY

Explanatory note Customer: 26 printed pages, 3ris., 5 tables, 1 application and 7 sources used.

Car, Lada Grant 2190, rear suspension, analysis of the node design, structuring factors affecting the reduction of the host performance, the concept of input control, determination of the sampling parameters, determining the percentage of marriage in the party.

The purpose of this work is to study the factors affecting the reduction of the performance of technical systems, as well as to gain knowledge of the quantitative marriage assessment according to the results of input control.

Work performed on the study of theoretical material, as well as work with real parts and samples of the systems under study. According to the results of the input control, a number of tasks were performed: the distribution law was determined, the percentage of marriage and the amount of selective combination of products to ensure a given control accuracy.

Introduction

1. Analysis of factors affecting the reduction of operability of technical systems

1.1 Construction rear suspension

1.2 Structuring factors

1.3 Analysis of factors affecting the rear suspension of the Lada Grant 2190

1.4 Analysis of the impact of processes to change the state of the elements of the rear suspension of the LADA grants

Results of input control

2.1 Input Controlness, Basic Formulas

2.2 Checking having a rough error

2.3 Determining the number of intervals by dividing the specified control values

2.4 Building a histogram

2.5 Determination of the percentage of marriage in the party

Conclusion

List of sources used

Introduction

To effectively manage the processes of changes in the technical condition of the machines and justify the activities aimed at reducing the intensity of the wear of the parts of the machines, in each particular case, to determine the type of wear of the surfaces. To do this, set the following characteristics: type of relative movement of surfaces (friction contact scheme); the character of the intermediate medium (type of lubricant or working fluid); The main wear mechanism.

In the form of the intermediate medium, wear is distinguished by friction without lubricant, by friction with a lubricant material, with friction with abrasive material. Depending on the properties of materials of parts, lubricant or abrasive material, as well as on their quantitative relations in conjugations, during operation, the destruction of surfaces of various species arise.

In real conditions, there are simultaneous types of wear at the same time. However, as a rule, it is possible to establish a leading type of wear, limiting the durability of parts, and separate it from other concomitant types of destruction of surfaces, which slightly affect the performance of the conjugation. The mechanism of the main type of wear is determined by studying worn surfaces. Observing the nature of the manifestation of the wear of the friction surfaces (the presence of scratches, cracks, traces of coloring, the destruction of oxide film) and knowing the properties of the materials of parts and lubricant material, as well as the data on the presence and nature of the abrasive, intensity of wear and the mode of conjugation, can be fully justified. On the form of wear of the conjugation and develop measures to increase the durability of the machine.

1. Analysis of factors affecting the reduction of the slaveABOUTConsturbation of technical systems

1.1 Rear suspension design

The suspension provides an elastic connection between the body and wheels, softening shocks and shocks, when the car is moving along the road irregularities. Thanks to its presence, the durability of the car increases, and the driver and passengers feel comfortable. The suspension has a positive effect on the stability and control of the car, its smoothness. By Lada Granta, the rear suspension repeats the design of the previous generations of Lada cars - the VAZ-2108 family, the VAZ-2110 family, Kalina and Priora. The rear suspension of the car is semi-independent, made on an elastic beam with longitudinal levers, cylindrical springs and telescopic duplex shock absorbers. The beam of the rear suspension consists of two longitudinal levers, connected by cross-section U - shaped section. Such a section provides a connector (crossbar) greater bending rigidity and smaller - torsion. The connector allows levers to move relative to each other in small limits. The levers are made of a variable section pipe - it sets them the necessary rigidity to the rear end of each lever welded brackets for fastening the shock absorber, rear shield brake mechanism And the axis of the wheel hub. The front levers of the beam are fixed by bolts in removable body spars bolt. The mobility of the levers is ensured by rubberometallic hinges (silent blocks), pressed into the front ends of the levers. The lower eye of the shock absorber is attached to the beam lever bracket. The shock absorber is attached to the bodice with a nut. The elasticity of the upper and lower connections of the shock absorber provide rod pillows and a rubberometallic sleeve pressed into the eye. The shock absorber is closed with a corrugated casing protecting it from dirt and moisture. During the suspension breakdowns, the stream of the shock absorber is rewarded with a compression stroke buffer made of elastic plastics. The suspension spring is based on the supporting cup (the steel stamped plate, welded to the shock absorber body), and the top - rests in the body through rubber gasket. The beam lever flange has an axis of the rear wheel hub (it is attached to four bolts). The hub with a compound roller bearing pressed into it is holding a special nut on the axis. The nut is made by a ring bin, which reliably stops the nut by jams into the duct of the axis. Bearing of the hub of a closed type and does not require adjustment and lubrication during the operation of the car. The springs of the rear suspension are divided into two classes: a more tough, or less tough. Class A springs are marked with brown paint, class B-- blue. With the right and on the left side of the car, the springs of the same class should be installed. Springs of the same class are installed in the front and rear suspension. In exceptional cases, it is allowed to install the class B springs in the rear suspension, if class A. Springs are installed in the front of the class A springs on the rear suspension, if the front of the class B class is installed.

Fig.1 Rear suspension Lada Grant 2190

1.2 Structuring factors

In the process of operation of the car, as a result of the impact on it, a number of factors (the impact of loads, vibrations, moisture, air flows, abrasive particles, when hitting the car dust and dirt, temperature effects, etc.), there is an irreversible deterioration of its technical condition associated with wear and damage to its details, as well as a change in a number of their properties (elasticity, plasticity, etc.).

The change in the technical condition of the car is due to the work of its nodes and mechanisms, the impact of external conditions and storage of the car, as well as random factors. Random factors include hidden defects of car parts, congestion of construction, etc.

The main permanent reasons for changing the technical condition of the car during its operation was wear, plastic deformations, fatigue destruction, corrosion, as well as physico-chemical changes in the material of parts (aging).

Wearing is the process of destruction and separation of material from the surfaces of parts and (or) accumulation of residual deformations when they are friction, manifested in a gradual change in size and (or) forms of interacting parts.

Wear is the result of the process of wear of parts, expressed in the change in their size, shape, volume and mass.

Different dry and liquid friction. With dry friction, the fuel surfaces of the parts interact directly with each other (for example, the friction of the brake pads about brake drums or discs or friction of the slave disk clutch about the flywheel). This type of friction is accompanied by increased wear of the rubbing surfaces of parts. With liquid (or hydrodynamic) friction between the driving surfaces of the parts, an oil layer is created, exceeding the microelectric surfaces of their surfaces and not allowing them of direct contact (for example, bearings crankshaft In the period of the steady operation), which dramatically reduces wear of parts. Practically, with the work of most mechanisms of the car, the above major types of friction are constantly alternate and transfers each other, forming intermediate species.

The main types of wear are abrasive, oxidative, fatigue, erosion, as well as wear during jamming, phreating and phreting corrosion.

Abrasive wear is a consequence of the cutting or scratching effects of the conjugate parts of solid abrasive particles (dust, sand) resulting from the driving surfaces (dust, sand). Finding between the driving parts of open friction hubs (for example, between brake pads and discs or drums, between springs, etc.), solid abrasive particles dramatically increase their wear. In closed mechanisms (for example, in a crank-connecting engine engine), this type of friction is manifested to a much lesser extent and is a consequence of the abrasive particles into lubricants and the accumulation of wear products in them (for example, with a late replacement of the oil filter and engine oil, untimely replacing damaged protective covers and lubricants in hinged compounds, etc.).

The oxidative wear occurs as a result of the impact on the rubbing surface of the conjugate parts of the aggressive medium, under the action of which fragile oxide films are formed on them, which are removed by friction, and the exposed surfaces are oxidized again. This type of wear is observed on the details of the engine cylinder-portion group, the parts of the brake hydraulic cylinders and clutch.

The fatigue wear is that the solid surface layer of the material of the part as a result of friction and cyclic loads becomes fragile and destroyed (sharpened), exposing the undergoing less solid and woven layer under it. This type of wear occurs on the treadmills rings of rolling bearings, gear teeth and gear wheels.

Erosion wear arises as a result of exposure to the surface of parts of moving at high speed of fluid flow and (or) gas, with the abrasive particles contained in them, as well as electrical discharges. Depending on the nature of the process of erosion and the prevailing effect on the details of certain particles (gas, liquid, abrasive), gas, cavitation, abrasive and electric erosion distinguish

Gas erosion consists in the destruction of the material of the part under the action of mechanical and thermal effects of gas molecules. Gas erosion is observed on valves, piston rings and engine cylinder mirror, as well as on details of the exhaust gas release system.

The cavitation erosion of parts occurs when the fluid flow continues is disappeared, when air bubbles are formed, which, torn near the surface of the part, lead to numerous hydraulic blows of the liquid about the surface of the metal and its destruction. Such damage is subject to engine parts in contact with coolant: internal cavities shirt cooling of the cylinder block, exterior surfaces of cylinder sleeves, cooling system nozzles.

Electro-erosion wear is manifested in erosion wear of parts of parts as a result of the exposure of discharges during the passage of the electron current, for example, between spark plug electrodes or interrupter contacts.

Abrasive erosion occurs during mechanical exposure on the surface of parts of abrasive particles contained in fluid flow (hydroabrasive erosion) and (or) gas (gaseous erosion), and is most characteristic of the exterior parts of the car body (wheel arches, bottom, etc.). Wearing during the jamming occurs as a result of setting, the deep breaking of the material of the parts and transfer it from one surface to another, which leads to the appearance of debasses on the working surfaces of the parts, to their encoffin and destruction. Such wearing occurs when local contacts occurred between rubbing surfaces, on which due to excessive loads and speed, as well as the lack of lubricant, the oil film is rupture, strong heating and "welding" of metal particles. A typical example is the jamming of the crankshaft and the burden of the liners in violation of the engine lubrication system. Warming in Freating is the mechanical wear of the contacting surfaces of parts at small oscillatory movements. If, in this case, under the influence of the aggressive medium on the surfaces of the conjugate parts, oxidative processes arise, then wear on the phret-corrosion. Such wear can occur, for example, in the contact places of the crankshaft necks and their beds in the block of cylinders and bearing caps.

Plastic deformations and destruction of car parts are associated with the achievement or exceeding the limits of fluidity or strength, respectively, in plastic (steel) or fragile (cast iron) of parts of parts. Damage data is usually a consequence of violation of the rules of operation of the car (overload, incorrect control, as well as traffic accident). Sometimes plastic deformations of parts precede their wear, leading to change geometric sizes and reducing the durability of the part.

The fatigue destruction of parts occurs during cyclic loads exceeding the metal endurance limit of the part. At the same time, there is a gradual formation and an increase in fatigue cracks, leading to a certain number of load cycles to the destruction of the part. Such damage occurs, for example, by spring and semi-axes with long-term operation of the vehicle in extreme conditions (long-term overload, low or high temperatures).

Corrosion occurs on the surfaces of parts as a result of the chemical or electrochemical interaction of the material of the part with an aggressive environment, leading to oxidation (rust) of the metal and, as a result, to reduce the strength and deterioration of the appearance of the details. The strongest corrosive effect on the parts of the car are salted used on the roads in winter time, as well as spent gases. He strongly contributes to corrosion preservation of moisture on metal surfaces, which is especially characteristic of hidden cavities and niches.

Aging is a change in the physicochemical properties of materials of parts and operational materials during operation and during the storage of a car or its parts under the action of an external environment (heating or cooling, humidity, solar radiation). So, as a result of aging, rubber products lose their elasticity and cracks, in fuel, oils and operational liquids Oxidative processes that change their chemical composition are observed and leading to the deterioration of their operational properties.

To change the technical condition of the car, conditions of operation are significantly influenced by: road conditions (technical category of road, view and quality road coat, slopes, climbing raises, rounding radii road), movement conditions (intensive urban traffic, road traffic), climatic conditions (ambient temperature, humidity, wind load, solar radiation), seasonal conditions (dust in summer, dirt and moisture in the fall and spring), environment aggressiveness (sea air, salt on the road in winter, reinforcing corrosion), and also transport conditions (car load).

The main activities that reduce the depreciation rates of parts during the operation of the car are: timely control and replacement of protective covers, as well as replacing or cleaning filters (air, oil, fuel), which prevent the parts of the abrasive particles to enter the rubbing surfaces; Timely and high-quality fixing, adjustment (adjustment of valves and tension of the engine circuit, wheel installation angles, wheel hub bearings, etc.) and lubricants (replacement and tapping oil in the engine, gearbox, rear axle, replacement and supplement oil in the hub wheels, etc.) works; Timely restoration of the protective coating of the bottom of the body, as well as the installation of the shoes that protect the arches of the wheels.

To reduce corrosion parts of the car and primarily the body must maintain their purity, to carry out timely care for the paintwork and its recovery, to produce anticorrosive treatment of hidden body cavities and other corrosion parts.

Competitively called this condition of the car, in which it meets all the requirements of the regulatory and technical documentation. If the car does not correspond to at least one requirement of regulatory and technical documentation, it is considered faulty.

A working condition is called such a state of the vehicle in which it corresponds to only the requirements that characterize its ability to perform the specified (transport) functions, that is, the car is operational if it can transport passengers and loads without a threat to traffic safety. A working vehicle may be faulty, for example, to have a reduced oil pressure in the engine lubricant system, a degraded appearance, etc. If the car is inconsistent, at least one of the requirements characterizing its ability to carry out transport operation, it is considered inoperable.

The transition of the car into a faulty, but the working condition is called damage (disruption of a good condition), and in an inoperable condition - failure (disruption of a working condition). Working Wear deformation Detail

The limit state of the car is called such a condition in which its further use on purpose is unacceptable, it is economically impractical or restoring its health or performance is impossible or inexpedient. Thus, the car goes to the ultimate state when there are fatal violations of safety requirements, the costs of its operation are inconsistently increasing, or there is a non-resistant output of the technical characteristics for the permissible limits, as well as an invalid reduction in the efficiency of operation.

The car's fitness is to withstand the processes arising from the above harmful effects of the environment when performing a car of its functions, as well as its adaptability to restore its initial properties is determined and quantified with the help of its reliability indicators.

Reliability is an object property, including a vehicle or its component part, to save the value of all parameters characterizing the ability to perform the required functions in the specified modes and conditions of application, maintenance, repairs, storage and transportation. Reliability as a property characterizes and allows you to quantify, firstly, the current technical condition of the car and its component parts, and secondly, how quickly there is a change in their technical condition when operating under certain operating conditions.

Reliability is the complex property of the car and its components and includes the properties of reliability, durability, maintainability and persistence.

1.3 Analysis of factors influencing the rear suspension of the Lada Grant 2190

Consider the factors affecting the reduction of the car's performance.

Faults and breakdowns can be from any car, especially as for the suspension. This is explained by the fact that the suspension suffers a constant vibration when driving, softens blows, and takes the entire weight of the car, including passengers and luggage, on itself. Based on this, a grant in the body of Liftbek is more susceptible to breakage, rather than a sedan, since the body of a liftbek, has a greater luggage compartmentdesigned for greater weight. The first problem facing most often is the presence of a knock or extraneous noise. In this case, you need to check the shock absorbers, as they need a timely replacement, and can often fail. Also, the reason may be, not until the end of the shock absorbers fastening bolts. Also, with a strong impact, not only the sleeves will be damaged, but the racks themselves. Then the repair will be more serious and expensive. The last cause of the pendant knock may be a burst spring. (Fig. 2) In addition to the knocks, you need to check the suspension mechanism for the presence of flops. If such traces are detected, this may indicate only one - the malfunction of the shock absorbers. If the entire liquid is found, and the shock absorber dries, then when entering the pit, the suspension will have a bad resistance, and the vibration from the impact will be very strong. The solution of such a problem is quite simple - to replace the wear element. The last malfunction that occurs on the grant - when braking or acceleration, the car leads to the side. This suggests that on this side, one or two shock absorbers are worn, and somewhat more stronger than the others. Because of this, the body is formed by an advantage.

1.4 Analysis of the impact of processes to change the state of the elements of the rear suspension of the LADA grants

To prevent emergency cases on the road, it is necessary to diagnose the car in general and the responsible nodes in particular. The best and qualified place to identify the fault of the rear suspension is the car service. You can also appreciate the technical condition of the suspension on their own during the movement of the car. When driving at a small speed on an uneven road, the suspension should work without knocking, squeaks and other extraneous sounds. After moving through the obstacle, the car should not swing.

Checking the suspension is better to combine with checking the status of tires and bearing wheel hubs. One-sided tire tread wear testifies to the deformation of the beam of the rear suspension.

This section covered and analyzed influencing factors to reduce the performance of the car. The influence of factors leads to the loss of performance of the node and the car as a whole, therefore, preventive measures must be carried out to reduce factors. After all, abrasive wear is a consequence of the cutting or scratching effects of the conjugate parts of solid abrasive particles (dust, sand) resulting from the driving surfaces. Finding between driving parts of open friction units, solid abrasive particles dramatically increase their wear.

Also, to prevent destruction and increase the life of the rear suspension, it is necessary to strictly follow the rules of operation of the car, avoiding its work on the limit modes and with overloads, this will extend the service life of responsible parts.

2. Quantitative marriage assessment in the party by pE.Aspects of input control

2.1 The concept of input control, the basic formulas

Under quality control it is understood as the verification of the compliance of the quantitative or qualitative characteristics of the products or the process, on which the quality of products determined by the technical requirements.

Product quality control is part of The production process and is aimed at checking reliability in the process of its manufacture, consumption or operation.

The essence of product quality control in the enterprise is to obtain information on the state of the object and comparing the results obtained with the established requirements recorded in the drawings, standards, supply contracts, technical assignments.

The control provides for testing products at the very beginning of the production process and during the period of operational services, providing in case of deviation from the regulated quality requirements, the adoption of corrective measures aimed at the production of proper quality products, proper maintenance during operation and complete satisfaction of the consumer's requirements.

Under the input quality control of products, it is necessary to understand the quality control of products intended for use in the manufacture, repair or operation of products.

The main tasks of the input control can be:

Obtaining with a lot of accuracy of assessing the quality of products for control;

Ensuring the unambiguity of mutual recognition of the results of assessing the quality of products carried out by the same methods and by the same monitoring plans;

Establishing compliance of product quality assigned requirements for the purpose of timely presentation of claims to suppliers, as well as for prompt work with suppliers to ensure the required level of product quality;

Preventing the startup into production or repair of products that do not meet the established requirements, as well as permission protocols according to GOST 2.124.

Quality control is one of the basic functions in the quality management process. It is also the most surround function according to the methods used, which are devoted to a large number of works in different areas of knowledge. The control value is that it allows you to reveal errors in order to then quickly correct them with minimal losses.

Under the input quality control of products is understood to be the control of products received to the consumer and intended for use in the manufacture, repair or operation of products.

Its main purpose is to eliminate defects and the compliance of products by the established values.

When conducting input control, apply plans and procedures for the statistical acceptance control of product quality alternatively.

Methods and means used on the input control are selected taking into account the requirements for the accuracy of measuring the quality indicators of controlled products. The logistics departments, external cooperation in conjunction with the technical control department, technical and legal services form requirements for the quality and range of products supplied under contracts with suppliers enterprises.

For any accidentally selected product, it is impossible to determine in advance whether it will be reliably. Of the two engines of one brand in one, refusals can soon arise, and the second will be a good time.

In this part of the course project, we will define a quantitative assessment of marriage in a batch based on the results of input control using the Microsoft Excel table processor. The table with the values \u200b\u200bof the workflows to the first failure due to the exit of Lada Grant 2190 (Table 1), this table will be the source data for calculating the percentage of marriage and the volume of the selective amount of products.

Table 2 Values \u200b\u200bof developments before the first failure

2.2 Checking having a rough error

Rough Error (Promach) - This is the error of the result of a separate measurement included in a number of measurements, which for these conditions is sharply different from the other results of this series. The source of coarse errors may be sharp changes in the measurement conditions and errors made by the researcher. These include a breakdown of the device or push, the wrong countdown on the measuring instrument scale, incorrectly record the results of the observations, chaotic changes in the voltage parameters that feeds the measurement means, and the like. Frames are immediately visible among the results obtained, because They are very different from other values. The presence of misses can greatly distort the result of the experiment. But the rapid discarding distinguished from other measurement results can also lead to significant distortion of measurement characteristics. Therefore, the initial processing of experimental data recommends any combination of measurements to check for coarse misses using the "Three Sigm" statistical criterion.

The criterion "Three Sigm" applies for the measurement results distributed by normal law. This criterion is reliable when measuring N\u003e 20 ... 50. The average arithmetic and secondary quadratic deviation is calculated excluding extreme (causing suspicion) values. In this case, the result is the result, if the difference exceeds the value of 3ow.

The minimum and maximum sampling values \u200b\u200bare checked on a rough error.

In this case, all the measurement results must be discarded, the deviations of which from the average arithmetic exceeds 3 , And the judgment on the dispersion of the general population is made according to the remaining measurement results.

Method 3 it showed that the minimum and maximum value of the source data is not a rough error.

2.3 Determination of the number of intervals by splittingn.control values

Essential to build a histogram is the choice of optimal partition, since with increasing intervals, the detailing of the distribution density estimate is reduced, and the accuracy of its value drops with a decrease. To select the optimal number of intervals n. Often applies the Rule of Stargez.

The Sturgges rule is the empirical rule of determining the optimal number of intervals to which the observed range of changes in the random variable is divided when the histogram of the density of its distribution is divided. Named by American Statistics Herbert Sturgès.

The resulting value is round to the nearest integer (Table 3).

Breaking at the intervals is performed as follows:

Lower border (N.G.) is defined as:

Table 3 Interval Definition Table

Increased MIN value
The average value of MAX
For MAXFL MIN.
Dispersion
For MIN.
Dispersion
Rough Error 3? (min)
Rough Error 3? (MAX)
Number of intervals
Length interval

Upper border (VG) is defined as:

The subsequent lower boundary will be equal to the upper previous interval.

The interval number, the values \u200b\u200bof the upper and lower borders are specified in Table 4.

Table 4 Border Definition Table

Interval number

2.4 Building a histogram

To build a histogram, it is necessary to calculate the average interval value and their average probability. The average value of the interval is calculated as:

The values \u200b\u200bof the average interval values \u200b\u200band probabilities are presented in Table 5. The histogram is presented in Figure 3.

Table 5 Table of average values \u200b\u200band probability

Middle interval	The number of input control results in the boundaries	Probability

Fig.3 Histogram

2.5 Determination of the percentage of marriage in the party

The defect is every single non-compliance with the products established requirements, and products having at least one defect is called defective ( marriage, defective products). Dustophice products are considered suitable.

The presence of a defect means that the actual value of the parameter (for example, L.e) does not correspond to the specified normalized parameter value. Consequently, the condition of lack of marriage is determined by the following inequality:

d.min? L.d? d.mAX,

where d.min d.max is the smallest and largest maximum permissible values \u200b\u200bof the parameter defining its tolerance.
List, view and extreme-permissible values \u200b\u200bof parameters characterizing defects are determined by product quality and data given in the regulatory and technical documentation of the enterprise for manufactured products.

Distinguish correlated production marriage and final production marriage. The product refers to the product, which is technically possible and economically appropriately corrected in the conditions of the manufacturer; To the final - products with defects, the elimination of which is technically impossible or economically unprofitable. Such products are subject to disposal as waste production, or implemented by the manufacturer at a price much lower than the same product without marriage ( delivered goods).

By the time of detection of production marriage of products can be internal (detected at the production stage or in the factory warehouse) and external(Discovered by the buyer or other person using this product, poor-quality goods).

During operation, the parameters characterizing the performance of the system are changed from the initial (nominal) y.n to limit y.p. If the value of the parameter is greater than or equal y.n, then the product is considered faulty.

The limit value of the parameter for nodes ensuring the safety of the road movement is taken at a probability value B \u003d 15%, and for all other aggregates and nodes with B \u003d 5%.

The rear suspension is responsible for the safety of the road, therefore the probability B \u003d 15%.

With B \u003d 15%, the limit value is 16.5431, all products with the measured parameter are equal to or above this value will be considered faulty

Thus, in the second section of the course project, determined the limit value of the controlled parameter based on the first kind error.

Conclusion

In the first section of the course project, influencing factors on the decline in the operability of the car were considered and analyzed. The factors that affect directly selected node were also considered. ball support. The influence of factors leads to the loss of performance of the node and the car as a whole, therefore, preventive measures must be carried out to reduce factors. After all, abrasive wear is a consequence of the cutting or scratching effects of the conjugate parts of solid abrasive particles (dust, sand) resulting from the driving surfaces. Finding between driving parts of open friction units, solid abrasive particles dramatically increase their wear.

Also, to prevent destruction and increasing the life of the rear suspension, it is necessary to strictly follow the rules of operation of the car, avoiding its work on limit modes and with overloads, this will allow to extend the service life of responsible parts.

In the second section of the course project, determined the limit value of the controlled parameter based on the first kind error.

List of sources used

1. Collection technological instructions for the maintenance and repair of the car Lada Grant OJSC AvtoVAZ, 2011g, Tolyatti

2. Avdaev M.V. et al. Machine repair technology and equipment. - M.: Agropromizdat, 2007.

3. Bortz A.D., Zakin Ya., Ivanov Yu.V. Diagnostics of the technical condition of the car. M.: Transport, 2008. 159 p.

4. Gribkov V.M., Karpecin P.A. Equipment handbook for both trot cars. M.: Rosselkhozidat, 2008. 223 p.

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coursework, added 01/09/2013


Reliability of machinery and performance criteria. Stretching, compression, crash. Physical and mechanical characteristics of the material. Mechanical transmissions rotational motion. The essence of the theory of interchangeability, rolling bearings. Construction materials.

This term paper consists of two chapters. The first chapter is devoted to the practical use of the theory of reliability of technology. In accordance with the task to perform the course work, indicators are calculated: the likelihood of trouble-free operation of the aggregate; the probability of the failure of the aggregate; the density of the probability of failure (the law of the distribution of random variable); The coefficient of completeness of the restoration of the resource; recovery function (leading failure stream function); Failure intensity. Based on the calculations, graphic images of a random variable are being built, the differential distribution function, changing the intensity of gradual and sudden failures, the diagram of the formation of the recovery process and the formation of the leading recovery function.
The second chapter of the course work is devoted to the study of the theoretical foundations of technical diagnostics and the assimilation of practical diagnostic methods. This section describes the assignment of diagnostics on transport, the structural and investigative steering model is being developed; all possible methods and steering tools are analyzed from the point of view of completeness of identifying faults, laboriousness, cost, etc.

List of abbreviations and symbols 6
Introduction 6.
Main part 8.
Chapter 1. Basics of practical use of reliability their 8
Chapter 2. Methods and means of diagnosing technical systems 18
List of references 21

Work contains 1 file

Federal Agency for Education

State Educational Institution of Higher Professional Education

Tyumen State Oil and Gas University

Branch Muravlenko

Department of Eom

COURSE WORK

by discipline:

"Basics of operability of technical systems"

Performed:

Student Group STEZ-06 D.V. Shilov

Checked: D.S. Bykov

Muravlenko 2008.

annotation

This term paper consists of two chapters. The first chapter is devoted to the practical use of the theory of reliability of technology. In accordance with the task to perform the course work, indicators are calculated: the likelihood of trouble-free operation of the aggregate; the probability of the failure of the aggregate; the density of the probability of failure (the law of the distribution of random variable); The coefficient of completeness of the restoration of the resource; recovery function (leading failure stream function); Failure intensity. Based on the calculations, graphic images of a random variable are being built, the differential distribution function, changing the intensity of gradual and sudden failures, the diagram of the formation of the recovery process and the formation of the leading recovery function.

The second chapter of the course work is devoted to the study of the theoretical foundations of technical diagnostics and the assimilation of practical diagnostic methods. This section describes the purpose of the diagnostics on transport, the structural-effect steering model is being developed, all possible methods and means of diagnosing steering, analysis is carried out from the point of view of completeness of identifying faults, laboriousness, cost, etc.

Task on coursework

22 option. Main bridge.
160	160,5	172,2	191	161,7		100	102,3	115,3	122,7	150
175,5	169,5	176,5	192,1	162,2		126,5	103,6	117,4	130	147,7
166,9	164,7	179,5	193,9	169,6		101,7	104,8	113,7	130,4	143,4
189,6	179	181,1	194	198,9		134,9	105,3	124,8	135	139,9
176,2	193	181,9	195,3	199,9		130,5	109,6	122,2	136,4	142,7
162,3	163,6	183,2	196,3	200		133,8	107,4	114,3	132,4	146,4
188,9	193,5	185,1	195,9	193,6		122,5	108,6	125,6	138,8	144,8
158	191,1	187,4	196,6	195,7		105,4	113,6	126,7	140	138,3
190,7	168,8	188,8	197,7	193,5		133	111,9	127,9	145,8	144,6
180,4	163,1	189,6	197,9	195,8		122,4	113,6	128,4	143,7	139,3

List of abbreviations and symbols

ATP - Motor Transport Enterprise

SV - random variables

Then - maintenance

Utt - Technological Transportation

Introduction

Automobile transport develops with high quality and quantitatively rapid pace. Currently, the annual increase in the global car fleet is 10-12 million units, and its number is more than 100 million units.

In the Machine-Building Complex of Russia, a significant number of products manufacturing and processing industries are united. The future of motor vehicles, organizations of the oil and gas complex and enterprises of the municipal sphere of the Yamalo-Nenets region is in an inseparable connection with their equipment with high-performance equipment. The performance and serviceability of cars can be achieved by the timely and qualitative performance of work on their diagnosis, maintenance and repair.

Currently, in front of the automotive industry, tasks are set: reduce by 15-20% specific solid capacity, increase the work resource and reduce the complexity of maintenance and repair of cars.

Efficient use of technology is carried out on the basis of a scientifically based planning and preventive system of maintenance and repair, allowing to ensure a working and serviceable state of machines. This system allows you to increase productivity based on ensuring the technical readiness of machines with minimal costs for these goals, improve the organization and improve the quality of maintenance and repair work, to ensure their safety and extend the service life, optimize the structure and composition of the repair and service base and the planned Its development, speed up scientific and technical progress in the use, maintenance and repair of machines.

Manufacturers, receiving the right to independently trade by the manufactured products, should simultaneously be responsible for its performance, providing spare parts and the organization of technical service throughout the service life of the machines.

The most important form of the participation of manufacturers in the technical service of machines is the development of corporate repair of the most complex assembly units (engines, hydrotransmission, fuel and hydraulic equipment, etc.) and restoration of worn items.

This process can go along the way to create its own industries, as well as with the joint participation of existing repair factories and repair and mechanical workshops.

The development of the scientifically based technical service, the creation of the service market and competition is presented with strict requirements for technical service performers.

With the existing growth in the pace of road transport at enterprises, an increase in the quantitative composition of the automotive park of enterprises there is a need to organize new structural units of ATP, whose task is to carry out work on the repair of road transport.

An important element of the optimal organization of repair is the creation of a necessary technical base, which predetermines the introduction of progressive forms of labor organization, an increase in the level of mechanization of work, equipment productivity, reducing labor costs and means.

Main part

Chapter 1. Basics of practical use of reliability theory.

The initial data for the calculation of the first part of the course work are developments to the refusal of fifty the same type of units:

Working to the first refusal (koms.km.)

160	160,5	172,2	191	161,7
175,5	169,5	176,5	192,1	162,2
166,9	164,7	179,5	193,9	169,6
189,6	179	181,1	194	198,9
176,2	193	181,9	195,3	199,9
162,3	163,6	183,2	196,3	200
188,9	193,5	185,1	195,9	193,6
158	191,1	187,4	196,6	195,7
190,7	168,8	188,8	197,7	193,5
180,4	163,1	189,6	197,9	195,8

Working to the second refusal (koms.km.)304,1

331,7 342,6 296,1 271 297,5 328,7 346,4 311,4 302,1 310,7 334,7 338,4 263,4 304,7 314,1 336,6 334 323,7 280,7 316,7 343,5 338,1 302,8 276,7 318 341,6 335,1

Random variablesextensions for refusal (from 1 to 50) they have in order of increasing their absolute values:

L. 1 \u003d L. mIN. ; L. 2 ; L. 3 ; ...; L i. ; ... L. n-1. ; L. n. \u003d L. max , (1.1)

where L. 1 ... L. n. – Implementation of random variable L.;

n -number of implementations.

L MIN \u003d 158; L Max \u003d 200;