Automatic gearbox (automatic transmission) - type of transmission in the machine, in which the speed switching is carried out due to electronics, without requiring the driver's attention.
The first development, which can be attributed to the Class of automatic transmission appeared in 1908 at the Ford Plant in America. The model T, was equipped with a planetary, while a manual gearbox. This device It was not automatic, and demanded from drivers a certain set of skills and action to control, but was much easier to use than the transmission transmission at the time without synchronization.
The second important stage in the appearance of modern ACPs was the transfer of clutch management from the driver to the servo in the 1930s of the 20th century by General Motors. Such automatic transmission was called semi-automatic.
The first truly automatic planetary checkpoint "Kotal" was established in Europe in 1930. At this time, various firms in Europe developed friction and brake ribbons.
The first automatic transmission was very expensive and unreliable until the end of the 30s did not begin experiment on the introduction of hydraulic elements into their design to replace servo drives and electromechanical controls. This way of development went to Chrysler, who developed the first hydrotransformer and hydromefluoron.
Modern designs of the automatic transmission were invented in 40-50 years of the 20th century by American designers.
In the 80s, the 20th century, the automatic transmission began to be equipped with computer control, 4 and 5-step automatic transactions appeared to the fuel economy.
Device automatic transmission and work principles
The main elements of the automatic transmission are always the same:
The hydrotransformer that performs the role of clips. The rotational movement on the wheels of the car is passed through it. Its main task is to ensure uniform rotation without shocks. The hydrotransformer consists of large wheels with blades immersed in hydrotransformer oil. The transfer of moment is carried out not at the expense mechanical device, And with the help of oil flows and pressure. The hydrotransformer contains both the reactor responsible for smooth and high-quality changes in the torque on the wheels of the car.
Planetary transmission that contains a set of speeds. It is blocking some gear and unlocking others by defining the selection of the gear ratio.
A set of frictions I. brake mechanismsresponsible for the transition between gear and selection of transmission. These mechanisms are blocked and stop the elements of the planetary transmission.
Control devices (hydroblock) - controls the device. It consists of an electronic unit in which the box is controlled, taking into account all factors and sensors collecting information (speed, mode selection).
How does an automatic transmission work?
When the engine starts, the oil is supplied to the torque converter, the pressure begins to increase. The pumping wheel starts moving, the reactor and turbine are still. When the speed and supply of gasoline is turned on with an accelerator, the pumping wheel starts to rotate faster. Oil streams begin to run the rotation of the turbine wheel. These flows are thrown into a fixed reactor wheel, it returns back to the turbine wheel, increasing its efficiency. The moment from rotation is transmitted to the wheels and the car rows from the spot. When the desired speed is reached, the pumping and turbine wheel moves lonely quickly, while the oil flow falls on the reactor already on the other side (the movement occurs only one way) and it begins to rotate. The system switches to hydromefta mode. If the resistance on the wheels is growing (lifting uphill), the reactor stops rotating again and enriches the pumping wheel with a torque. During the achievement of the required speed and moment, the transmission change occurs. The electronic unit The control applies to the command, after which the brake tape and friction breaks inhibit reduced transmission, and the increase in oil pressure through the valve accelerates the increased, due to this and switch without loss of power. When the engine is stopped or reduced the speed, the pressure in the system decreases and reverse switching occurs. On the engine off, the torrotransformer is not under pressure, so the start of the engine with the "Tolkach" is not possible.
Advantages and disadvantages
Compared to mechanical gearboxes, automatic has significant advantages:
- car with automatic transmission is easier and more comfortable to manage, additional skills and reflexes are not required by the driver, switching speeds are more smooth, which is especially relevant for movements around the city;
- the engine and the leading parts of the car are protected from overload and their resource rises;
- the resource of many automatic transmission significantly exceeds a similar MCPP resource. With timely maintenanceThe need to repair comes less frequently.
Consumables, such as, for example, a clutch or cable, are missing, the automatic transmission is much more complicated. The resource of the automatic transmission of American and Japanese production, with modern service can reach a million kilometers.
It is believed that car with automatic transmission has a slightly greater fuel consumption. By the end of the 20th century, it was often incorrectly chosen moments and a limited number of speeds (2-3). On modern automatic transmission, the number of gears is at least 4-5 (on freight to 19). Modern computer automation copes with a selection of torque and speed no worse than the driver. In addition, fuel consumption on machines with MCPP strongly depends on the manner of driving and professional driver skills. Modern automatic transmission has many modes, they are adapted to driving a car owner.
A serious disadvantage of automatic transmission is the impossibility of accurate and safe shift in extreme conditions - on overtaking, departure from a snowdrift by fast switching of the rear and first gear (squash), launching the engine "from the Tolkach". However, most urban residents will choose a comfortable movement of traffic jams instead of the possibilities of the "wanted" driver.
The second misconception of motorists is that the automatic transmission is not intended for driving a car in conditions of racing and off-road. Civil automatic transmission is really not intended for sports driving and driving management - they do not have appropriate cooling for such loads, and switching moments are selected for calm driving in urban environments. However, the automatic transmission equipped with additional cooling and reassembered speeds will show best results than manual transmission. Cars Formula 1 complement automatic transmission and with a very fast movement coped better than racing cars with manual transmission. Long, managed drifts are also possible. Off-road cars have been equipped with automata for a long time, which do not affect the passability. Most drivers simply do not understand how the automatic transmission works.
Characteristics and opportunities
The automatic transmission allows you to better drive a car, reducing the driver's action requires a clutch control and switching knob, makes driving less tedious. Automatic transmission has a neutral position, parking position (the box rotation is blocked additionally with the help of aggregates), rear transmission And several speeds for movement. Switching is carried out on the basis of speed and conditions (for example, when driving on a lift, reduced speed can automatically be turned on). The switching time of a good gearbox for urban cars is around 150 ms, which is much faster than the reaction of the usual driver.
The main control body of the automatic transmission is the gear handle, it can be located in the steering area (old American and Japanese sedans or modern minivans) or at the traditional location of the ACP lever. On the old models of the class luxury, the box could be controlled using the keypad.
In order to avoid random switching or dangerous situations, the automatic transmission applies different kinds Protection. In cars with automatic transmission, you cannot run the engine if the selector is in the speed position. Switching the modes is carried out using the button for floor layouts of the lever, or pull off the lever when it is located on the steering wheel. With parking, the car can be removed only when the brake is pressed. In some cases, the slot is performed in the form of steps.
Generally accepted automatic transmission modes:
P - Parking, automatic transmission is mechanically blocked, when in horizontal surfaces, use parking brake not necessary.
N - neutral. You can tug a car.
L (d1, d2, s) - reduced transmission (1 transmission or 2 transmission).
D - automatic switching mode from the first speed.
R - reverse mode. In addition, the OVERDRIVE button may be present at the automatic transmission, prohibiting the transition to higher transmission when overtaking.
Neutral gear is usually located between D and R or R is in the opposite end of the selector handle. This requirement was introduced to avoid emergency situations on the road and parking.
Also, various modes and protocols of work may be present in the automatic transmission. ECO - economical mode, for different firms is implemented in different ways.
* Snow (WINTER) - Trokhan from a place with a second or third transmission for slippery road coat or moving in a snowdrift or dirt.
* Sport (Power) - transmission switches at more high revolutions Engine.
* SHIFTLOCK (Button or Key) - Unlocking the selector when the engine is turned off, is used to transport the machine if the engine or battery has failed.
Some automatic transmission have manual gear. The most successful and distributed option such automatic transmission was the Tittronic created by Porsche. Distinctive feature It is the control body, it is made in the form of the letter H and has the characters "+" and "-".
In addition to the tytitronic, the variator and robotic gearbox can be attributed.
Vehicle features with automatic
The automatic transmission device is more complicated than the manual transmission. The automatic transmission repair is much more complicated - it consists of a much larger number of spare parts. Usually, the malfunctions of the automatic transmission testify kicks and pauses when switching gears, reverse or one of the speeds can generally abyss. In other cases, the car can stop moving.
Diagnosis of automatic transmission is usually carried out in several stages:
Visual oil control. If the oil is black or contains metal fragments in its composition - this indicates internal damage or wear of the automatic transmission. Replacing oil in automatic transmission, which can solve the main part of the problems.
Diagnosing errors using the diagnostic connector. Could fail the electronic controls of the box (sensors, computer), after which the box can not function normally.
Test drive work automatic transmission, for this study the behavior of the box during the ride.
Pressure measurements in each automatic transmission mode.
Inspection of the internal state of the ACP.
The repair of automatic transmission can only mean with 1 to 3 item of this list. For other operations need warm box, Special equipment and experienced specialist. The last operation will require a lift, crane and a whole set of tools. Removal, installation and replacement of automatic transmission one of the most complex and time-consuming car repair. Repair of the insides of the automatic transmission can be comparable at cost with installing a new or contract box. It will be better if the diagnosis of automatic transmission and repair will be produced by specialists.
To avoid such troubles, it is necessary to monitor the level and color of the oil in the box and change it in a timely manner (when it is written in the regulations). For different automatic transactions apply various oilsdescribed in the literature on the car. In Honda cars, Honda applies its special oil if you pour another box can fail.
It is necessary to operate the machine with the most carefully, not allowing slipping, constant sharp braking and accelerations.
In the cold season, the automata must be given time to be saturated with thickened butter. To do this, warm the car, turn on the transmission and stand on the brakes at least a minute, after which you can touch.
For most people, compliance with this kind of simple operations will not cause problems. In their case, the automatic transmission will last for them for a very long time. Modern automatic transmission is very reliable in design, it is not very expensive than their mechanical fellow, give a sense of comfort behind the wheel and seriously facilitate the life of any driver.
Each car owner knows that the choice of transmission is a key factor that affects the dynamic indicators of the car. The developers are constantly trying to improve the gearbox, but most motorists still give preference to the manual transmission, since, due to the current stereotype, it is believed that it is more reliable and easy to use. However, the reason lies in the other - most people are simply not familiar with the principle of the machine, therefore and fear it.
In today's article, we will try as much as possible and accessible to describe the principle of operation. automatic transmission.
What is automatic transmission?
ACAP is the main element of the car transmission design, the main purpose of which is to change the torque, as well as changes in the speed of movement. There are three options for automatic transmissions:
- Variable speed drive;
- Hydraulic machine;
- Robotic;
What is better - mechanics or automatic?
As many people could have noticed, most Russian motorists prefer the manual transference. Some experts believe that this is due to the mentality of the nation, others with established negative stereotypes.
Another thing is Americans, 95% of which do not imagine the process of driving a car, without an automatic box. But it does not surprise this at all, because the automatic transmission was invented by American engineers who wanted to simplify the life of drivers.
The same situation in Europe. If 15-20 years ago, everyone was widely used by the mechanics, then it is already almost displaced from the market.
Russia also has an increase in the popularity of the machine, but, according to experts and analysts, the Russians do not know how to properly use the automatic box. Every day, the auto repair shops addresses the mass of motorists with faults, the main reason for which is incorrect operation.
How does the automatic transmission work?
In order for the principle of operation of the automatic transmission more clearly, we cut it into three parts: mechanical, electronic and hydraulic.
Let's start a discussion, of course, with mechanical, since it is exactly this element and switching transmissions.
The hydraulic part is a certain intermediary who is a link.
And finally, the electronic, which is considered to be a transmission brain responsible for switching modes, as well as feedback.
Everyone understands that the heart of the car is the engine. The transmission does not pretend to this role at all, because it can safely call the brain of the car. The main objective of the automatic transmission is considered to convert km of a motor into force, which creates conditions for the TC movement. An important role in this process is performed by a hydrotransformer and planetary transmissions.
Hydrotransformer
By analogy with the manual transformer, the clutch functions, and also adjusts the KM, taking into account the speed of rotation and the produced engine power.
The structure of the torque converter consists of three parts:
- Centripetal turbine;
- Centrifugal pump;
- Guide apparatus reactor;
Due to the fact that the turbine and pump are most close as possible with each other, the working fluids are in constant motion. It is due to this that it is possible to achieve minimal energy losses. In addition, the torque converter boasts very compact sizes.
It is worth noting that the crankshaft is directly connected to the pumping wheel, and the box shaft is with a turbine. It is at the expense of this that there is no tough connection between the leading and slave elements in the hydrotransformer. The working fluids transmit energy from the motor to the transmission, which, in turn, through the pump blades transmits it to the turbine blades.
Hydromefta
If we talk about the hydromule, then its principle of work is very similar - it also transmits km without affecting its intensity.
The hydrotransformer is equipped with a reactor first in order to change km. In fact, it is the same wheel with blades, except that the tougher planted and less maneuverable. Over it returns from the turbine into the pump. Some features have a reactor blades, whose channels are gradually narrowed. Due to this, the speed of movement of workers fluids increases significantly.
What is the automatic transmission?
The torque converter interacts with the clutch, and does not contact the driver.
The planetary series - interacts with gears in the box, and when switching transmissions changes the transmission configuration.
Brake tape, rear and front friction - directly switch transmissions.
The control device is a node that consists of a pump, a valve box and an oil separator.
Hydblock is the system of valve channels that control and control the engine load.
The hydrotransformer is designed to transmit torque from power aggregate to the elements of the automatic transmission. It is located between the box and the engine, and thus performs the adhesion function. It is filled with the working fluid, which catches and transmits the engine's efforts into the oil pump located directly into the box.
As for the oil pump, it already transmits the working fluid to the hydrotransformer, thus creating the most optimal pressure in the system. Therefore, the myth that the car with the machine can be started without a starter - a clean lie.
The gear pump receives energy directly from the engine, from which it can be concluded that when the motor is turned off, the pressure in the system is completely absent, even if the switching lever is not in the initial state. Therefore, forced rotation cardanian Vala Can not start the engine.
Planetary series - is often used in automatic transmission, as it is considered more modern and technological, rather than the parallel shaft used in the mechanics.
Pieces of friction - piston makes movement of excessive oil pressure. The piston itself is very tightly pressed the leading elements to the slave, forcing them to rotate as a whole, and transfer km to the sleeve. It is worth noting that several such planetary mechanisms are located in the automatic transmission.
Friction disks transmit KM directly by the wheels of the car.
Brake tape - used to block the elements of the planetary mechanism.
Hydbot is one of the most complex mechanisms in the automatic transmission, which is called "brains of transmission. It is worth noting that the repair of this element is very expensive.
Types of automatic transmission
Permanent race technical Equipment Car, forces developers to invent increasingly sophisticated technologies and structures in order to overtake competitors. It is worth noting that this positively affects the development of the chassis of the vehicle. One of the most important discoveries was the invention of an automatic transmission. It immediately began to use incredibly great demand, as it simplifies the management process noticeably. In addition, it is very simple in operation and reliable. Analysts argue that in the near future it will fully displace from the MCPP market.
To date, the automatic box is used as in passenger carsand trucks, regardless of the type of drive.
It is known that when driving a car with a manual transmission, you have to keep your hand on the gear switch, which significantly reduces the concentration on the road. The carton-machine is practically devoid of such flaws.
Main advantages Box automatic:
- Management increases;
- A smoother transition between transmissions even at high speed;
- The engine is not overloaded;
- Transmissions can be shifted both manually and automatically;
Modern automatic transmission, from the point of sight of the control and control system, can be divided into two types:
- Transmission with hydraulic device;
- Transmission S. electronic device, or so-called robotic box;
It should be more understandable after reading the example below:
"Imagine the situation that the car moves along roven road And gradually approaches the steep rise. If for a while just from the side to watch this situation, then it can be noted that after an increase in the load, the machine begins to lose speed, and, therefore, the intensity of rotation of the turbine is also reduced. This leads to the fact that the working fluid begins to counteract the movement. In this case, the rate of circulation increases sharply, which contributes to an increase in km to the indicator in which equilibrium in the system will occur. "
The same principle of work and at the time of the start of the car movement. The only difference is that this case The accelerator is also involved. Thanks to it, it increases the intensity of crankshaft and pumping wheel, despite the fact that the turbine remains still, which allows the engine to work in idle mode. It is worth noting that the CM increases sharply, and when a certain mark is reached, the torque converter begins to perform the function of the link, which connects together the slave and the presenter elements. All these moments, it is possible to significantly reduce the level of fuel consumption significantly, and more effectively carry out the engine braking in case of need.
So for what then to connect the automatic transmission to the hydrotransformer if he is independently able to change the intensity of the CM?
That is why: the coefficient of change of torque using a torque converter usually does not exceed 2-3.5. This is not enough for the full operation of the automatic box.
Unlike mechanical, the automatic box switches the speed with the help of friction clutches and tape brakes. The system automatically determines the desired speed, taking into account the speed of movement and effort on the accelerator pedal.
In addition to the planetary mechanism and the hydrotransformer, the automatic transmission includes a pump that lubricates the box. Cooling radiator is engaged in cooling oil.
The difference between a box-machine at the rear-wheel drive and front-wheel drive vehicles
There are a number of differences between the arrangement of automatic transmission cars with the front and rear wheel drive. Automatic transmission front-wheel drive More compact, and has a separate compartment, which is called differential.
In all other aspects, both transmissions are identical in both constructive and functional terms.
To effectively perform all functions, the automatic box has the following elements: a torque converter, a control unit and a motion mode selection mechanism.
We hope that our article has become the most useful as possible for you, and helped you understand the principles of the automatic transmission.
Video
An article on how to properly use the box "Automatic" - characters on the automatic transmission panel, starting the motor, movement and stop, possible errors. At the end of the article - video about the use of an automatic box.
Currently distinguish three types of automatic transmissions: "Classical", with " stepless variator", With" robotic mechanics ". Depending on the modification and manufacturer, the specified types of transmissions may differ slightly (different number of gears, a slightly different course of the lever - direct or zigzag, notation, etc.), but the basic functions will be the same for all.
The growing popularity of the automatic transmission is fully explained - it is more convenient to operate (than "mechanics" - MCPP) especially for beginners, reliable and protects the engine from overloads. It seems to be simple! However, the driver's mistakes are still allowed, and even the most reliable mechanism may fail if it is incorrectly operated. Next, we will look at how to properly use the automatic transmission and how to competently exploit it.
To learn how to use the "automatic" to correctly, you must first figure out what the letter symbols mean ( english letters) And the numbers on the automatic transmission panel with the gear shift handle. Immediately, we note that, depending on the brand of the machine, the numbers and letters may vary.
- "P" - "Parking". Turns on when parking a car in the parking lot. A certain analogue of the parking brake, only with the blocking of the shaft, and not with the pressed brake pads.
- "R" - Reverse. Turns on to move backwards. Usually it is called - "rear speed".
- "N" - "neutral". Neutral transmission. Often referred to - "neutral". In contrast to the Parking mode "P", in neutral mode "n" the wheels are unlocked, so the machine can move rolling. Accordingly, the machine can also spontaneously turn to a bias on the parking, if the wheels are not fixed with manual brake.
- "D" - "Drive". Movement mode forward.
- "A" - "Automatic". Automatic mode (practically the same as the "D" mode).
- "L" - "Low" (low). Low gear mode.
- "B" - The same mode as "L".
- "2" - Movement mode not higher than the second transmission.
- "3" - Movement mode not higher than a third gear.
- "M" - "Manual". Manual control mode with increasing / lowering through the signs "+" and "-". This mode simulates the mechanical switching mode with the manual transmission, only in a simpler version.
- «S» - "Sport". Sport mode of movement.
- «OD» - Overdrive. Enhancement (accelerated mode).
- "W" - "Winter". Movement mode for winter periodin which touch starts from the second transmission.
- "E" - "Economy". Movement in economy mode.
- "HOLD" - "Holding". Used together with "D", "L", "S", as a rule, on the machines of the Mazda brand. (Read the manual).
For example, in the manual of some vehicles, the letter "B" means "Block" - the differential lock mode, which cannot be turned on while driving.
And if B. all-wheel drive car There are "1" and "L" designations, the letter "L" may not mean "Low" (down), but "Lock" (Castle) - which also denotes blocking of differential.
Starting the engine with an automatic box has the following features:
- In the car with automatic transmission of only two pedals: "brake" and "gas". Therefore, the leader's left foot is practically not used. When starting the engine, the gas pedal is not pressed, but the brake pedal in some brands can be pressed, otherwise the engine will not start (read the operating manual).
However, driving instructors advise to take a rule - before starting the engine with the automatic transmission to press the brake pedal always. This will prevent the spontaneous movement of the machine at neutral mode "N", and will also allow you to quickly go to the modes of motion "D" or "R". (Without pressing brake pedals switch to the specified modes and it will not work from the place).
- In cars with automatic transmission provides protection - Automatic engine start lock with incorrect transmission lever. This means that the engine with automatic transmission can be started only if the gear lever is in one of two positions: or "P" (Parking), or "N" (neutral). If the lever of the PP will be in any other position intended for movement, the blocking protection from incorrect launch will be triggered.
This protective function is very useful, especially for beginners, and especially in cities with great " automotive density"Where in the parking lots and in streams cars are tight to each other. After all, even experienced drivers sometimes forget to "remove a car from speed" before starting the engine, as a result of which the machine immediately starts to go and crashes into the nearest car or obstacle.
You can run the engine with automatic transmission as in "P" mode (Parking) and in "N" mode (neutral), but manufacturers recommend using only "P" mode. Therefore, it is better to establish another rule for yourself - parking and run the engine only in Parking mode.
- After turning the key in the ignition lock before starting the starter, it is recommended to wait a few seconds.To give time to turn on the fuel pump and pump up compression.
Most drivers who are transplanted from "mechanics" to "AUTOMATIC", the first time mechanically perform the actions that they are used to repeatedly perform when driving on a car with a manual transmission. Therefore, such drivers before starting to travel with automatic transmission on the road in the overall car stream, it is recommended to pre-train alone.
So, the standard procedure for starting from a place by car with automatic transmission is as follows:
- Insert the key to the ignition lock.
- Squeeze the brake pedal with the right foot (left foot when driving with automatic transmission is not activated).
- Check the position of the gear lever - it must be in the Position "P" - "Parking".
- Run the engine (when the brake pedal is pressed).
- Also, when the brake pedal is pressed, switch the PP lever to the "D" position is "Drive" (forward).
- Completely release the brake pedal, after which the car is touching and starts moving forward at low speed - about 5 km / h.
- To increase the speed of movement, you must click on the "Gas" pedal. The stronger you push the gas pedal, the higher the transmission and speed will be.
- To stop the car, you need to remove the right leg with the "Gas" pedal and squeeze (her) brake pedal. The car will stop.
- If you plan to leave the car after the stop, then when the brake pedal is pressed, move the gear lever to P "Parking". If the stop required in traffic, at the traffic light or pedestrian crossingNaturally, the PP lever to switch to "Parking" is not needed. After you decide again to continue moving, release the brake pedal and click on the gas pedal to increase the speed.
To prevent engine damage when switching to manual mode "M" on the go, all automatic transactions have special protection. Go to manual control "M" is relevant in the following situations:
- When moving off-road on low transmission to avoid slipping.
- When moving rolling from a slide, with braking engine. Use for movement in rolling neutral mode "n" is not recommended, since it is harmful to automatic transmission. And the gas in "D" mode is not entirely convenient, as there is a gradual decrease in speed.
- For convenient passage of turns and other maneuvers, including for sharp acceleration when overtaking.
- The most common mistake leading to the crash of automatic transmission is inclusion of the "D" mode - "Drive" (forward) without a complete stop when moving by reverse. And, the same, only on the contrary - the inclusion of the "R" mode (reverse) without a complete stop when moving forward.
- The second common error (rather, the error) is associated with the "N" mode (neutral). The fact is that this mode is emergency to unlock the wheels for short-term towing or permuting the machine in the event of any malfunction. And just for this!
But many inexperienced drivers use neutral mode "N" in traffic jams with short-term stopsWhat leads to hydraulic impact and premature wear of the automatic transmission. In traffic jams, with frequent stops, you need to use the "D" mode along with the brake pedal. If you need to stop - the brake pedal is pressed, if you need to slowly move forward - the brake pedal is simply released, and the car slowly rolls forward. And so you can ride all day.
- Third error - transition to neutral mode "N" from the "D" mode on the go, in motion along the track. It is dangerous (especially at high speed), as the engine can stumble, with the result that the hydraulic steering and the strengthening of the brakes will turn off, and the car will become almost uncontrollable.
- Another error - towing machines with automatic transmission for a distance of more than 40 km and at speeds more than 50 km / h. In the "Automatic" box, in contrast to the manual transmission, the oil supply system operates under pressure, but when towing it does not work. Accordingly, the details of the "automat" rotate "on dry", without lubrication, resulting in their very rapid wear.
- Non-error is attempting to start the car with automatic transmission "from the pusher". And although such attempts often lead to the desired result (the engine is started), it is still on the mechanism of automatic transmission, it acts destructively, and with such frequent exploitation "AUTOMAT" may not work out half of the resource.
Conclusion
It is possible that for someone, the automatic transmission will seem complex and pick-up mechanism, despite the simplicity and convenience of using it. But this is only at first glance. In fact, the "automata" has proven itself as quite reliable units, but, of course, subject to their correct and competent operation. It is especially convenient to use automatic transmission in large cities where you often have to stand in traffic jams.
Video on how to use the "automatic":
Thanks constructive features The automatic transmission provides with the help of automation the choice of the vehicle necessary for the movement, without participating in this driver's process. At the same time, unlike the mechanical gearbox, the right hand of the driver is released from movement shifting movements and disappears the need to equip the car with a clutch pedal, which also eliminates the driver's movement of the driver to squeeze the clutch from the process.
To start moving the car, equipped with automatic transmission, the driver is enough to translate the box of the box to the desired position and then it remains only to adjust the speed of gas and brake pedals. Driving a vehicle equipped with an automatic box is much easier, which gives more opportunity The driver will focus on the road atmosphere.
Regardless of the type, any transmission - whether it is mechanical or automatic, performs the same functions in the car - efficient use of the engine torque, but different ways Based on its design features.
Device automatic
The operation of the automatic transmission is based on the operation of its planetary mechanisms and the hydromechanical drive. In a small engine speed, the automatic machine allows a car to move in a large speed range. To the main elements devices automatic transmission include the following mechanisms:
- hydrotransformer;
- planetary reductor;
- packages of frictional;
- brake band;
- control device.
Main nodes and principle of operation of automatic transmission
Basic principle of operation of automatic transmission It should be the property of fluid when rotating transmit energy. This property made it possible to create a device (hydromefta, a torque converter), in which there is no rigid connection between the input and output shafts, and the mechanical energy between these shafts is transmitted using the stream working fluid.
The torque converter in the automatic transmission performs the function of automatic transfer of torque from the power unit to the main gearbox nodes, which corresponds to the function of the clutch node in mechanical box Transmissions. After reaching certain revolutions by the engine, using the working fluid pressure on the slotransformer nodes - the pumping wheel, which is rigidly connected to the crankshaft of the power unit and the turbine wheel, interconnected with the main gear shaft, the torque transmits. During a decrease in the revolutions of the power unit, fluid pressure on a turbine wheel falls, and it stops. Accordingly, the engagement of the engine with the box is interrupted.
Due to the fact that the hydrotransformer is limited in the possibility of transmitting mechanical energy in wide ranges, it is connected to the planetary multi-stage transmissions that ensure the switching of speeds and reversing rotation.
By your device, the planetary gearbox is a gear rotating around the central - "sunny" gear. It functions by blocking and separating certain elements of the planetary row. For three-speed automatic transmission, two planetary mechanisms are used, and in four-speed - three.
Packages of frictional or friction system are mechanisms that block the moving elements of the planetary gearbox. On its device, this is a set of several movable and stationary rings, which under the influence of the hydraulic pusher stalls, which ensures that the appropriate transmission is switched.
The brake tape takes part in the transmission, which temporarily blocks the necessary elements of the planetary gearbox. The principle of its work is the effect of self-installing used to block these elements. Having a relatively small size, the brake tape softens the mechanisms at the time of their work.
The control device is intended to regulate the functioning of the brake ribbon and the work of the friction. It consists of a block of valves having spools, springs, channel system and other elements. The control device performs the gear shift function based on the specific conditions of the vehicle movement - when it accelerates it uses increased gear, and when braking is low.
Modes of operation of automatic transmission
Automatic transmission can operate in several standard modes. All of them are designated still in the past century symbols in Latin: P, D, N, R.
Parking mode "P" or parking. - Provides all gears off. In this case, drive wheels are blocked by gearbox mechanisms, and it is disabled from the engine. In this mode, the engine is launched.
Video about the warming of the "Automatic" box:
Movement Mode "D" or drive. - Provides automatic switching Transmissions when moving a car forward.
Mode "N" or neutral transmission - Provides the leading wheel of the car from the gearbox. This mode is used during short stops or, if necessary, towing a car.
Reversing Mode "R" - Provides car movement with reversal.
The driver management of the automatic box must be performed in the set sequence: 1. Parking; 2. Reverse; 3. neutral; 4. Movement.
In modern automatic transmission for a comfortable ride, additional modes of operation are provided.
Mode reduced transmission "L" - Used during slow motion in a complex road atmosphere. In this mode, the gearbox only works on the selected transmission, regardless of the change in the power unit.
Modes "2" and "3" - Used when towing cargo by vehicle or in appropriate conditions. The numbers indicate the number of fixed transmission on which the car moves.
Overdrive mode «O / D» or "Overdrive" - Used for frequent automatic activation of the increase. Such a mode provides a more economical and uniform movement of the car, mainly on the highway roads.
City Mode Mode "D3" - limits the automatic switching of the transmission box.
Retired traffic mode "NORM" - allows a box to switch to increased transmissions when the average rotation values \u200b\u200bis reached crankshaft Engine.
Winter Movement mode «S» or "SNOW" (It can also be denoted by the "W" or "Winter" symbol - allows the car to start moving from the second transmission, thereby preventing the running wheels. Also, during the movement, the operation of the automatic transmission is performed more gently using low engine speeds.
Automatic box The gear is part of the transmission capable of adjusting the torque and vehicle speed. This means that you no longer need to count the moment when clamping the clutch and let it go, as well as switch the speeds manually.
In this article, consider the principles of the mechanism.
History of creating an automatic transmission
Transmission automation historically occurred in three stages. The first attempt to make a car more independent undertaken Henry Ford at the beginning of the twentieth century. Ford T had a planetary KP, which demanded less skills from motorists to switch speed than an ordinary mechanical.
On the next Stage In the production of cars with semi-automatic transmission. In them, automation is directed either to independent shifting gear, or to refuse to use the clutch, which significantly facilitated driving a vehicle.
Did you know? Such a semi-automatic transmission is still used on scooters.
The last step towards the transmission to the automatic transmission was the system proposed by developers american company GENERAL MOTORS. It was based on the planetary model, which was previously used at the Ford factory, as well as hydraulics, which herself was included at the time when it is necessary to change the transmission. Both principles underlie the modern automatic transmission. 
Device of nodes and mechanisms
The automatic transmission conditionally consists of three main parts:
- Mechanical. Its responsibilities include changing the vehicle speed, as well as direct speed switching.
- Hydraulic. This part of the automatic transmission transfers the torque between component parts KP without any driver actions.
- Electronic. This component is the brain of the gearbox, which monitors the operation of mechanical and hydraulic SystemsAnd also transmits signals to other vehicles of the car.
Components of automatic KP:
Did you know? In the USSR, the first hydrotransformators began to be used on cars such as "seagull", "Volga", ZIL, as well as some other vehicles.
Principle of operation
Any automatic transmission is based on a planetary gearbox, which consists of a sun gear and united by the drive and the crown gear. These nodes as much as the vehicle has a car.
Principle of operation:
- All pulses on the gearbox come with two inputs connected to the crown and solar gears, and are transmitted through one output, which is provided by rotation drove.
- When the pulse arrives at the entrance to the sun gear, they begin to rotate, which leads to rotation drove.
- She drove, in turn, makes moving the crown gear, which entails a constant increase in the speed of rotation drove at the exit.
- If the driver needs to go to rear goThe sun gears will start moving in the opposite direction.
The automatic transmission does not have a direct connection between the inlet and output shaft. They are combined with an intermediate shaft, on which two packages of friction discs connecting with the gear are closed in operating condition. Did you know? Over the past year, in Europe, 80% of all purchased cars operate on a box of automatic. On the territory of the CIS countries, the purchase of cars with automatic transmission is only 10% of the total number of vehicles sold.
It is these discs that transmit power. Friction discs at the input of smaller diameter than at the output. This is explained by increasing the power of rotation during the transfer of the pulse from the entrance to the exit.
Pros and cons
Let's look at what pluses and minuses can be encountered when using a car with an automatic transmission.
Pros:
- convenience.No longer need to be distracted by switching speeds and use of clutch. The driver can be completely concentrated on the road;
- it is easier to move from the scene. Responsible for this process in the automatic transmission is electronics, and not the correct pressing of the clutch or gas pedal;
- car nodes have a longer service life due to electronics control. Very often, drivers, especially newcomers, do not switch the speed in time, which leads to a violation of the engine operation, or delay the adhesion, or work at all without it, which leads to its bravery.
Minuses:
- cars with automatic transmission have a high cost. Moreover, they are also more expensive in service than vehicles on a manual transmission;
- there are difficulties in bad weather. The main way to go out of drift or dirt is "Running", which is impossible when using the automatic box.
Important! During the switching speeds using a selector, it is impossible to put pressure on the gas pedal.
A car with a box machine is designed for people who value comfort. To determine which type of transmission is needed to you, should be practiced in driving and with mechanical, and with an automatic transmission.
The principle of operation of the automatic transmission: video
