How does the hydrotransformer work? Automatic transmission principle of work as a car automatic transmission

Article Video How does the gearbox work automat? What are all the advantages and charms of controlling a car with an automatic box, how reliable and durable automation, which is possible and what can not be done if you have a machine gun, and whether the automatic transmission is really "stupid" as they say or can "make it »A car on the mechanics and leave it far behind? Read in this article!

Device automatic

The gearbox automat consists of several main nodes:

The location of the elements in the automatic box:

Planetary system of gears

The heart of the automatic box is the planetary mechanism.

Planetary mechanisms Have 3 degrees of freedom. This denotes that one of the 3-elements (satellites does not count) must be stopped for transmitting rotation.

If you do not stop any of the elements, then everyone can perform free movement, and in this case there will be no rotation transmission.

You can slow down and other elements, as well as change the entry and output points, getting different gear ratios and reverse direction of rotation.

In this case, the external dimensions of the design will change insignificantly. Such properties and determined the use of planetary mechanisms in the automatic box.

Gearbox automatic, small video on the subject of the device:

Hydrotransformer

To transmit torque from the gearbox, the automatic machine for the engine is a torque converter. In essence, it performs almost the same functions as the grip in the mechanics.

In addition, it can increase torque due to a decrease in fluid flow rate reactor.

Principle of operation of the hydrotransformer:

The torque converter consists of three main elements.

These are two blades, one side of the box, the other from the engine side. Between them is the so-called reactor. All of these three parts are not connected mechanically, they are in a special fluid.

When rotating blades connected to the engine, the torque with a liquid is transmitted to the blades connected to the box, and the box starts working.

The geometrical characteristics of the blades of the hydrotransformer and the sections are selected in such a way that the torque transmitted from the engine is very small and can be parried even with a slightly pressing on the brake pedal.

However, a small press on the gas pedal, and a slight increase in revolutions, causes a significant increase in the transmitted torque.

It happens because, with an increase in the engine speed, the direction of the fluid current is changed to the increase in pressure on the turbine blades

Modern automatic transformers can increase the torque transmitted from the engine from two to three times. This effect takes place only when the crankshaft rotates much faster than the input shaft of the automatic transmission.

As the speed dialing is set, this difference decreases and the moment comes when the input shaft rotates, almost at the same speed as the crankshaft, but not exactly, since the transmission of the torque from the engine on the automatic transmission is carried out through the liquid, i.e. With slippage.

This is part of the explanation why cars with automatic transmission are less economical and dynamic rather than the same with the MCPP.

To minimize these losses, the torque converters are equipped with locks. When the angular velocities of the blade wheel and the turbine are aligned, the blocking connects them into a single integer, excluding slippage.

To connect the elements of the planetary mechanism to the input shaft of the box automatize the coupling, and for stopping relative to the body of the brake. And those and others most often represent multi-disc clutches.

Hydraulic system

Working fluid in gearbox hydraulic system - aTF oil, Provides lubricant, cooling, gear shift and a transmission connection with an engine. As a rule, oil in the box is in the crankcase.

Because Oil volume during operation ACPs changes, it is connected to atmospheric air through probe.

As Pressure source in automatic transmissionthe gear pumps with internal engagement are used. The advantage of gear pumps with internal engagement lies in high power pump, especially at low speed.

Or simply automatic transmission, appeared in the automotive industry significantly later mechanical transmissions. However, such devices quickly found the use of almost all types of road transport and are now used everywhere. One of the elements of the automatic transmission is its hydrotransformer, without which the normal functioning of the entire system would be impossible. Today we will tell about the principles of operation of the hydrotransformers installed on the automatic transmission, and give an exhaustive answer to the question: why does such a design need and what role does it perform on the car?

Purpose

To clearly imagine what role the hydrotransformer in the automatic transmission is performed, it is necessary to recall the assignment of an ordinary clutch, which is universally installed on the gearbox of a mechanical type.

The clutch performs the role of the link between the engine and the transmission. In other words, if the clutch is not disabled, then all one hundred percent of the motor is transmitted by the gearbox, and, consequently, the wheels. In addition to everything, the MCPP itself allows the driver to choose the transmission itself and change the torque, which allows you to achieve maximum engine efficiency when driving and tritely not to give it to it in place when the wheels are not driven by rotation.

The main disadvantage of mechanical gearboxes in front of the "machine" is that in addition to the permanent selection of the speed manually, the clutch pedal must squeeze. If this is not done, there is a risk of increasing extremely expensive and burn the grip, which will lead to the need to replace it.

For these purposes, the transformer began to apply. This element is arranged much more difficult than clutch on the manual transmission, which consists of only two disks - the leading and slave.

But the hydrotransformer allows you to solve the most important and unpleasant feature of the "mechanics" - the need for a constant interaction of the driver with the clutch pedal. So, no longer have to squeeze the pedal when switching gear, and the traffic lights do not have to hold it at the speed on.

Then the question arises: whether it is impossible to apply an ordinary grip on the automatic transformer on the automatic transformer, as on the manual transformer? The answer to the impossibility is simple - the automatic transmission itself chooses the moment when the transmission must be switched, and the driver does not know this moment in advance. Therefore, it is not possible to press the clutch pedal on time. From here there is a need to introduce into the automatic transformer automatic transformer, which repeatedly facilitates the interaction of the driver and the box.

Structure

Despite the fact that the hydrotransformer on the automatic transmission has a rather complicated principle of operation, the overall structure of the system is still similar to mechanical clutch. As far as we know, the clutch consists of two shafts - the lead, which is rigidly connected to the engine, and the slave, which is connected to the transmission.

On the hydrotransformer installed on the automatic transmission, there is also a leading and slave elements. But in return to the disks rigidly adjacent to each other, these functions perform two turbines that rotate opposite each other and do not have a hard connection.

The question arises here: what principle two turbines will interact with each other? How will they transmit a torque between them, providing, thus, the movement of the car in a predetermined mode? It turns out that the binding role in this system does not perform a rigid element, but a liquid that is oil.

Due to its high density, the oil allows not only a permanent lubricant that will save metal from wear, but also the transmission of torque due to circulation under high pressure.

However, turbines are not all elements that are involved in the transmission of torque from the engine automatic box. There is another small turbine between the leading and slave element, which has a reactor name. Its purpose is to transform the transmitted energy, change the torque and the effort transmitted from the engine box. It is worth noting that in contrast to turbines, the reactor does not always rotate. Its functioning is only necessary in those moments when the wheels require the transmission of the moment other than the nominal.

Scheme of functioning

The leading turbine has the name of the pumping wheel and is rigidly connected to the engine flywheel. This means that its rotation speed can be changed by interacting with the accelerator pedal.

The leading turbine does not have its own name. It, unlike the pump, is connected to and, thus, the interaction with it. The reactor is located between the turbines and is rotated only from time to time.

Turbines and reactor have a system of oil canals. This allows oil when circulating through a strictly defined path, so there is a minimum wear of metal parts and the maximum efficiency of their operation is achieved.

When the car is in place, it is necessary that the led turbine remains fixed. This is necessary so that the car is simply not stupid, and its engine did not stop his work at idling.

In this mode, the effect of the clutch pedal is mimic - the oil pressure is minimal, and therefore the turbine does not have any indirect interaction.

As soon as the car begins to come into motion, the number of pump revolutions increases, and therefore oil pressure increases. Due to this, the led turbine begins to rotate with a given force, and the wheels come into motion. When reached certain speeds, the reactor is activated. It changes the pressure in such a way as not to allow the car to stumble and do not give the driver to feel the faults of the power.

Summary

The hydrotransformer is one of the most important components of any modern "automaton" providing it. good job. This device Carries out automated torque control when transmitting it from the engine to the wheels. This allows you to judge that with sharp failures of power and torque, it is worth paying attention to the state of this node and produce its qualitative diagnosis.

Oddly enough, but currently automatic transmission ( automatic box Shift shift) Increases popularity from motorists and future car owners. (Your humble servant belongs to opponents of this type of boxes). But about it below.

So, automatic trans ...

The main purpose of the automatic transmission is the same as the mechanics - the reception, transformation, transmission and changes in the direction of torque. Available automata in the number of transmissions, according to the method of switching, software and by the type of actuators used.

The operation of the automatic transmission is better to consider on a specific example, namely on a classic three-stage gearbox with hydraulic actuators (drives) and a torque converter. It should be noted that there are preselative automatic transmission.

The automatic transmission device includes:

1. Hydrotransformer - Mechanism providing transformation, torque transmission using working fluid. Working fluid for Automatic Usually, ready transmission oil For automatic transmissions. But many motorists use liquid for hydraulic drives of heavy truck (spindle), although it is incorrect. The spindle is not intended to work in the conditions of high speed of the gear movement.
2. Planetary reductor - A node consisting of "solar gears", satellites, and a planetary driving and the crown gear. Planetaryka is the main node of the automatic box.
3. Hydraulic control system - A complex of mechanisms intended to manage the planetary gearbox.

In order to more fully explain the principle of operation of the automatic transmission to begin with a torque converter.

Hydrotransformer

The torque converter serves at the same time clutch and hydromefta To transfer torque to the planetary mechanism.

Imagine two impellers with blades, located opposite each other at a minimum distance and enclosed in one case. In our case, one impeller is called a pumping wheel, which is connected hard with the flywheel, the second impeller is called turbine wheel and connected by means of a shaft with a planetary mechanism. Between blade impeller is a working fluid.

Principle of operation of the hydrotransformer

During, when the flywheel rotates, the pumping wheel rotates, its blades pick up the working fluid and direct it on the blades of the turbine wheel, under the action of centrifugal force. Accordingly, the turbine wheel blades come into motion, but the working fluid after performing the work departs from the surface of the blades and is sent back to the pumping wheel, thereby braking it. But it was not there! To change the direction of departing working fluid There is a reactor between the wheels, which also have blades and they are located at a certain angle. The following is the following - the fluid from the turbine wheel returning through the blades of the reactor hits the spacing of the pumping wheel, thereby increasing the torque, because there are two forces - engine and liquids. It should be noted that when the pumping wheel is started, the reactor is motionless. It continues until the pump turnover does not compare with the turns of the turbine wheel and standing still, the reactor will only interfere with its blades - to slow down the opposite movement of the working fluid. To exclude this process in the reactor is coupling free travel which allows the reactor to spin with the speed of impellers, this moment is called clutch point.

It turns out that when the nominal engine speed is reached, the engine power is transmitted to the planetary mechanism through ... Liquid. In other words hydrotransformer The automatic transmission turns into a hydromeft. So, the torque has already passed on - on the planetary mechanism?

Not! In order to transfer power from the engine, it is necessary that the drive clutch from the drive shaft has worked. But all in order ...

Planetary reductor

The planetary gearbox consists of:

1. planetary elements
2. clutch and brake couplings
3. tape brakes

Planetary element It is a node from the solar gear, around which satellites are located, which in turn are attached to the planetary drove. Around the satellites is the crown gear. Rotating, the planetary element transmits torque to the driven gear.

Clutch coupling is a set of discs and plates alternating with each other. Something Cuppet Cup is a motorcycle clutch. The clutch plates rotate simultaneously with the leading shaft, but the discs are connected to the element of the planetary row. For a three-step box of planetary series two - the first second transmission and the second third. The drive into action of the coupling is ensured by the compression of the disks and plates, this operation performs the piston. But the piston cannot move itself, it is driven by hydraulic pressure.

Ribbon brake Made in the form of a clamping plate of one of the elements of the planetary row and is driven by a hydraulic actuator.

For the concept of work of the entire box we will analyze the work of one planetary series. Imagine that the solar gear (center) slowed down (in the center), it means that the crown and satellites on the planetary drove remained. In this case, the speed of rotation will be less than the speed of the crown gear. If you allow the sun gear to rotate with satellites, and drove drilled, then the crown gear will change the direction of rotation (reverse). If the speed of rotation of the crown gear, drove and the solar gear will be the same, the planetary row will rotate as a whole, that is, without transforming torque (direct transmission). After all the transformations, the torque is transmitted to the driven gear and then on the shank box. It should be noted that we are considering the principle of operation of an automatic transmission in which the steps are located on the same axis, such a box is designed for cars with rear wheel drive and the front engine location. For front-wheel drive cars, the size of the box must be reduced, therefore, as a few slave shafts are entered.

Thus, the braking and releasing one or several rotation elements can be achieved changes to the speed of rotation and changes in the direction. All this process controls the hydraulic control system.

Hydraulic control system

Hydraulic control system It consists of an oil pump, a centrifugal regulator, valve systems, executing devices and oil channels. The entire control process depends on the speed of rotation of the engine and the load on the wheels. When moving from a place, the oil pump creates such a pressure at which the algorithm for fixing the elements of the planetary series is ensured so that the torque at the output was minimal, this is the first transmission (as mentioned above - the solar gear is slowed down in two steps). Further, when turning turns, the pressure increases and the operation includes the second stage on reduced turns, the first stage operates in direct transmission mode. Increasing the engine speed - starts working everything in direct transmission mode.

As soon as the load on the wheels increase, the centrifugal regulator will begin to reduce the pressure from the oil pump and the entire switching process will repeat up to the opposite.

When the reduced gear on the switch lever is turned on, such a combination of the oil pump valves is selected, in which the inclusion of increased gear is not possible.

Advantages and disadvantages of automatic transmission

Chief advantage automatic transmissionOf course, serves comfort when driving - the ladies are just delighted! And, undoubtedly, the engine does not work with an automatic operation in high load mode.

Disadvantages (and they are obvious) - Low efficiency, the complete lack of "drive" when starting from the place, a large price, and most importantly - the car with a machine cannot be taken from "Tolkach"!

Summing up, let's say that the choice of box is a matter of taste and ... driving style!

Partly it so, but knowing constructive features The automatic transmission and the principle of its work, you initially extend the life of your gearbox. In this article we would like to tell you about the main mechanisms and principles of the automatic transmission.

Content:

What is automatic transmission?

Automatic gearbox is an important constructive vehicle transmission element, which serves to change the torque, direction, as well as speed speed. And for the long separation of the engine from the transmission. Plishes stepless (variator), stepped (hydroautomatic) and combined transmissions (robotic).

It is no secret that the transmission has a basic influence on the dynamics of the car. Manufacturers are constantly experiencing and implemented the latest technology In our cars. Nevertheless, most motorists prefer to exploit cars with a manual transmission, as they believe that the latter's headache brings much less. In part, it is so, but knowing the design features of the automatic transmission and the principle of its work, you initially extend the life of your gearbox. In this article we would like to tell you about the main mechanisms and principles of the automatic transmission.

what better IPA. or automatic transmission

As a rule, our domestic motorist towards automatic transmissions refers to certain prejudices. Apparently the reason for our chronic reluctance to shift its problem on other people's shoulders and an attempt to independently eliminate it. For example, the Americans, and although they came up with automatic transmission, they do not suffer. American gearboxes are not popular in America and only 5% of American car enthusiasts from a hundred are used by mechanics. The popularity of automatic transmission and in Europe is growing from year to year with a huge pace. Of course, the fans of the machine are among our compatriots, that's just not to exploit them. According to car mechanics, it is untimely those. Maintenance and improper operation, often serves the root cause of all malfunctions of the automatic transmission.

How does the automatic transmission work?

In order to understand the principle of operation of an automatic gearbox - we can consecrate it into three parts: hydraulic, electronic and mechanical. As you can guess, the mechanical part is responsible directly for switching gear. Hydraulic transmits torque and creates an impact on mechanical. The electronic is the brain that is responsible for switching the modes (selector) and feedback With car systems.

As you know the heart of the machine is the engine, in the case of a gearbox, it is also appropriate. Transmission must convert the power and torque of the engine in such a way as to ensure the necessary conditions for the vehicle movement. Most of this hard work is performed by the hydrotransformer (it is "bagel") and planetary programs.

Hydrotransformer Depending on the frequency of rotation of the wheels and the load changes the torque automatically and performs the clutch functions (as in the manual box). In turn, consists of a pair of blade machines - a centripetal turbine and a centrifugal pump, as well as between them there is a guide reactor apparatus.

The turbine with the pump is as close as possible, and their wheels have a form that provides a continuous circle of circulation of working fluids. It is due to this that the hydrotransformer has minimal overall dimensions and minimal energy loss when flowing fluids from the pump to the turbine. The engine crankshaft is associated with the pumping wheel, and the gearbox shaft with a turbine. In view of this in the hydrotransformer there is no tough The links between the slave and the leading elements, the flows of working fluids carry out the transfer of energy from the engine to the transmission, which from the pump blades is discarded on the turbine blades.

How the automatic transmission video works:

Hydromefta and hydrotransformer

Actually, the hydromefta works on the same scheme without transforming its magnitude it transmits torque. The reactor is entered into the structure of the torque converter in order to change the moment. In principle, this is the same wheel with blades only rigidly planted on the body and until certain time is not rotating. On the way to which the oil from the turbine is returned to the pump is located. A special profile has a reactor blades, gradually inter-pump channels are narrowed. Due to this, the speed of working fluids current through the channels of the guide apparatus, gradually increases, and the fluid ejected to rotate in the direction of rotation from the reactor cares and pushes it.

What is the automatic transmission?

1. Hydrotransformer - similar to the grip in the fur. Corobke, but the control does not require the driver directly.
2. Planetary series - It is similar to the gearbox in the fur. Corrobke and changes the apparent attitude in the machine when switching transmissions.
3. Brake tape, rear friction, front friction - They serve to directly switch gear.
4. Control device - This is a whole node consisting of a gear pump, a valve box and an oil separator. The valve plate (hydroblock) is a system of channels with valves (solenoids) and plungers that perform control and control functions, also converts the engine load, the degree of pressing the accelerator and the speed of movement into hydraulic signals. Based on such signals, due to the sequential inclusion and exit from the working state of friction blocks, gear ratios are automatically changing.

Hydrotransformer Planetary series

Differences in the device automatic rear-wheel drive and front-wheel drive cars

There are also several differences in the device and layout of automatic rear-wheel drive transmissions and front-wheel drive. The front-wheel drive automobile automatic transmission is more compact and inside the housing is the separation of the main transmission that is, the differential. Otherwise, the principles of all automatic transactions are the same. To ensure the movement and execution of all automatic transmission functions, equipped with such nodes as: hydrotransformer, control unit and control, gearbox and motion mode selection mechanism.

Rear-wheel drive car Front-wheel drive car

Automatic transmissions are widely used in car designs, as we simplify the management of the vehicle. Machine owners need to know how to use a box-machine, since the resource and reliability of the product depends on the correct operation.

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Device and principle of operation of automatic transmission

The automatic transmission includes:

• hydraulic transformer;
• planetary mechanical gearbox (or compact);
• hydraulic control system;
• electronic control system;
• differential (in boxes of front-wheel drive cars);
• main pair (for front actuator).

The hydrotransformer is installed in the housing having a toroid form, which has a nickname among the Bagel mechanics.

UKPP hydrotransformer

The hydraulic transformer is a mechanism with a torque transmission of fluid flows. The device is located between the engine flywheel and mechanical part transmissions. As a working fluid, an oil is used, which has a reduced foamability and a viscosity stable and duration of operation. The transformer performs the role of clutch and changes the torque value removed from the flywheel of the power unit. The photo below shows general device boxes.

Automatic Box Concept

The structure of the hydrotransformer includes:

• the driving wheel equipped with pumping blades, which is rigidly connected to the flywheel;
• the slave wheel equipped with a turbine impeller, rigidly installed on the primary shaft of the mechanical part of the box;
• an additional blade reactor (stator);
• case.

The design of the wheels provides minimal gaps between the working elements, the seals are additionally installed that prevent fluid leakage. At the time of the beginning of the movement, pumping blades create a flow of oil. The emerging centrifugal force displays oil to the outer radius of the wheel. The stream falls on the turbine wheel, passing the torque on the primary shaft of the boxes associated with it. After that, the stream is sent to the reactor, passing through which the fluid returns to the input channels of the pump wheel. If you remove the reactor, the design will turn into a conventional hydromefluoron, which cannot regulate the torque value.

The reactor works in two modes - fixed and rotational. At the initial stage of the box, the reactor does not rotate, its blades are used to hold the fluid flow reflected from the turbine. When removing the reactor, this thread will come to the pump, braking it and reducing the efficiency of the transmission.

Holding the flow reactor increases the pressure of the fluid on the turbine wheel, thus adjusting the torque. After leveling the speed of the pump and the turbine, the reactor wheel starts to rotate. The moment of starting the reactor is called a clutch point. The reactor wheel rotates with a frequency corresponding to the turnover of the turbine.

However, the reactor does not allow you to adjust the moment in a wide range. In addition, the transformer design does not provide reverse transmission.

Visual image of the principle of operation of the transformer in the automatic transformer

Planetary Reducer Automatic Box

Mechanical gearboxes are used to expand the transformation range and ensure the reverse gear. Planetary mechanisms obtained the greatest distribution providing a wide range of changes. gear ratios at small overall dimensions. The gearbox consists of a central (solar) gear around which the satellites are rotated, installed on a common drill. Another gear (epicycle or crown) is installed on the peripheral part of the transfer.

The planetary gearbox in the automatic transmission is supplemented with friction and brake couplings, as well as tape brakes. Automatic boxes have several planetary gearboxes that are used when switching speeds. The number of gearboxes is one less than the number of speeds in the box. For example, a 4-speed box is equipped with three planetary gearboxes with a different gear ratio.

The clutch coupling consists of a set of disks and plates set alternately. The plates are rigidly fixed on the drive shaft, and the discs are connected to the parts of the planetary gearbox. Hydraulic coupling operation. Discs are made of soft friction material, plates - made of steel. The ribbon brake includes the friction surface (drum) mounted on the shaft and brake ribbon. The tape is fixed on the box crankcase and on the actuator hydraulic drive.

Planetary reductor

Automatic box hydraulics

To control the switching speed, a hydraulic drive is used to automate the process. In modern transmissions, hydraulics is complemented by electronic control units that control the operation of the system.

The composition of the hydraulics box includes:

• oil pallet, equipped with a magnetic element for collecting output wear products;
• oil pump with a centrifugal pressure regulator (spool type);
• filter for cleaning fluid from contamination;
• channels for serving the working fluid to the actuators:
• valve distributors.

The oil in the box is applied not only for the drive executive mechanisms, but also for lubricating and cooling nodes. The crankcase has two holes - to control the level with the help of the probe and the ventilation Sapun.

When working automatic transmission, it is necessary to maintain the level of fluid in the pallet. This parameter depends on the resource of the box and reliability of work.

The pressure regulator allows you to maintain the stream intensity at specified limits. Modern boxes are equipped with solenoid valves that are controlled by an electronic unit. The block changes the stream intensity depending on the speed of the auto, the opening angle throttle valve, resistance to movement and other parameters. The solenoid valves are used to adjust the stream in one or more highways, and also in speed switching drives. Valves are placed in a separate box located in close proximity to the pump. The case of the box is the so-called hydropholite - the part with a large number of channels for the liquid.

Hydroplitus automatic boxes

As executive mechanisms use hydraulic cylinders, transforming oil pressure into mechanical work. A special occasion of the hydraulic cylinder is a booster used to control the work of the disk brake or the lock mechanism.

The automatic box device on the example of the Toyota node is shown in the video, removed for the Channel Motor Machine Center.

Box work diagram

The principle of operation of the four-speed box:

1. Torque is fed to the central gear from the torque converter. At the same time drove the satellites blocked. In any automatic box there are at least two planetary transmissions, so the rotation from the first is transmitted to the second. The output shaft of the box receives a moment from the second planetary transmission.
2. The second transmission works with two planetary gears. On the first gear, the crown belt brake is blocked, the drill rotates with satellites. From this assembly, the moment goes to the second gearbox, in which the center gear stopped the coupling. The output shaft of the box receives torque from the crown of the second gearbox. The transfer number of the second transmission is calculated by multiplying the transfer numbers of the first and second gearbox.
3. The third gear is running the crown gear and drove the first gearbox. Due to this, the gearbox works as a whole, without changing the number of revolutions.
4. The fourth gear is boosting. The work is ensured by the stopping brake of the crown gear, the transmission of the moment goes through the central gear.
5. To turn on the reverse, the hold of drilled satellites in the second gearbox is performed. The torque enters the central gear of the second gearbox, which is then transmitted to the central gear of the first gearbox.

What is convenient for an automatic transmission?

Automatic transmission has several advantages:

1. Automatic speed switch simplifies the process of managing the car, as the number of pedals is reduced. The driver does not need to control the engine revolutions and the transmission enabled.
2. Vegetability of vehicle equipped automatic transmission, above. The increase in the passability is achieved by the exception of the power breaking break and torque when switching speeds.
3. Reducing dynamic loads transmitted on the power unit and transmission nodes.
4. Protection from running when the transfer is enabled. The internal control system blocks the starter when installing a selector into positions other than parking and neutral. Modern cars allow you to start starting only in the parking position.

The disadvantages of automatic boxes are usually attributed:

1. Power loss in the hydrotransformer, which lead to the growth of fuel. On modern multi-speed boxes, this disadvantage is eliminated by providing the optimal frequency of engine rotation and the introduction of the locking of the hydrotransformer with computer control.
2. Several reduced car dynamics with automatic transmission. The problem is solved on the boxes with two clutches that provide fast speed switching.
3. The impossibility of towing a car or launching a motor towing.
4. Fast wear of working elements in signless variastors. The impossibility of S. power plantsdeveloping torque more than 300 n / m.
5. The stuck car can not be released the star (fast switching of the first and reverse gear), because from such manipulations, the automatic box fails.

Types of automatic gearbox

On the modern cars Several types of automatic transmissions are used. The boxes are distinguished by the design and method of transmitting torque from the incoming shaft to the outgoing. The most common transmissions options are discussed below.

Hydromechanical gearbox

The design of the box includes three main nodes:

• hydraulic transformer;
• mechanical box;
• switching and control system.

There are two types of hydromechanical transmissions, characterized by the design of the mechanical part:

• with shafts (applied to cargo machinery or buses);
• with a planetary gearbox (on passenger cars and minibuses).

Switching gears in boxes equipped with valve gearboxes is carried out by multi-disc friction clutches of the "wet" type, i.e., working in the oil bath. To turn on the first or reduced transmission, a gear coupling can be used. A similar coupling is used to turn on the reverse transmission. The use of frictional provides smooth switching of speeds, without shocks and torque breaks. The disadvantage of the combat boxes are large sizes and noise of work. On the other hand, the massive design allows you to transmit a significant torque without the risk of nodes output.

In the planetary hydromechanical transmission, switching is performed by couplings and tape brakes. A feature of the design is the slip of the couplings and tapes of the box when switching any speed. Because of this, there is a decrease in the efficiency of the box. Plus, the transmissions are reduced dimensions and weight, but the cost of the product is higher, as well as the complexity of repair and maintenance.

The transformer can be blocked on hydromechanical transmissions. Such a mode of operation is indicated by Lock Up Torque Convertor Clutch. In this mode, the mode torque from the engine is supplied directly to the planetary gearboxes, turning the box to the mechanical unit. Locking and unlocking are performed automatically.

Hydromechanical planetary box Ford. in context

Variator (CVT)

The variator is a gearbox with a stepless change in the transfer ratio. The change in the number occurs depending on the external load and the operating conditions of the engine, which makes it possible to effectively use the characteristics of the power unit.

On cars used two types of variators:

• clinorem;
• friction.

The design of the clinoremable variator consists of two adjustable pulleys and a steel belt. The belt links have a cross section in the form of a trapezoid. Each pulley consists of two parts whose side surfaces form a working surface. Parts can move relative to each other, shifting the working surface along the radius.

When attaching half of the driving pulley, the belt is displaced to the outer radius, which leads to an increase in the gear ratio. The displacement occurs on the principle of a wedge that has fallen between two surfaces. Therefore, the design was named the clinorem. When diluted, Half pulley belt leaves between parts to the minimum point, reducing the gear ratio.

To achieve direct transmission, you need to set the same operating radii on pulleys. Steel belt can have a different design - in the form of a chain or consist of a set of steel plates. The scheme is clearly visible as a clinoremable variator.

Klinorenny variator Mercedes-Benz

Designation of nodes on the scheme of the variator:

• 1 - primary shaft;
• 2 - chain drive of the hydraulic system pump;
• 3 - starting torque converter;
• 4 - differential;
• 5 — ;
• 6 - slave pulley;
• 7 - secondary shaft of the box;
• 8 - planetary reverse gearbox;
• 9 - Leading pulley.

The composition of the clinoremable variator includes a small-sized clutch or a torque converter, which are used at the time of the start of movement. After starting the variator, these nodes are blocked. Direct control of pulleys is performed by servo drives that receive signals from an electronic control unit and sensors.

The frictional or toroidal variator is a set of coaxial disks and rollers that transmit torque. The name of the toroidal device was obtained by the form of working surfaces of the slave and the master element.

The transfer ratio is regulated by rearranging the rollers over the side surface of the disks. Due to significantly the strength of pressed the roller to the disk, the movement is possible using special mechanisms.

Other constructive solutions are possible. An example is the Nissan Extroid node, in which the roller is driving off with a hydraulic drive. After that, it moves independently (thanks to the shift relative to the axis of the disk). The principle of operation of the toroidal mechanism is well understood according to the scheme below.

Principle of operation of a toroidal variator Nissan

Robotic mechanics

This type of transmission is a conventional mechanical box with a speed switch by a robot, i.e. without the driver's intervention. Cars with a robot are not equipped with a clutch pedal, the switch selector is similar to a knot of an automatic transmission.

Mechanical Box VAZ with Robotic Clutch

Minuses of robotic boxes are:

• low smoothness of work;
• bad dynamics (partially corrected by the transition to "manual" mode);
• problems when driving on protracted lifts;
• overheating of clutch disks when moving in traffic jams.

Another option of a robotic box is a transmission with two clutches, first introduced into the production of Volkswagen concern under the trade designation of the DSG. The box uses two clutches, one of which serves even transmissions, and the second is odd.

• with the clutch of the "wet" type, which is the cause of power losses;
• with disks "dry" type.

Brief description of the principle of operation:

1. At the time of the start of the movement, the coupling of the first transmission is turned on by passing the torque, the second - is in the open state.
2. When a certain speed is reached the electronic unit Control disables the first clutch and includes the second.
3. After that, the first clutch is rebuilt on the third transmission management and expects the moment of switching.

Separate dSG box in context

The traditional pluses of the box include a very fast switching procedure, the box provides more dynamic overclocking than the usual mechanical transmission. Computer control of the work of the box allows to reduce fuel consumption by 10-12%. The main minus of the transmission is the accelerated wear of clutches, especially the "dry" type, due to which the shocks begin when switching

Cutting box

Transmission is mechanical, the car has a clutch pedal. The cam type gearbox does not have in the synchronizer design, switching is performed using cam couplings. The clutch is used when running from the place, further switching is performed with a reduced opening angle of the throttle valve. The switching lever moves in two directions - including increased or reduced speed. Such a mechanism is called sequential, resembles a speed switching device on motorcycle boxes.

To switch, a coupling is used, equipped with several large cams (no more than 5-7), which are engaged with cams installed on gear gear. The engagement has a significant side clearance that allows you to accelerate the inclusion of speed. The disadvantage of the box are shock loads on the engine and the rest of the transmission nodes. For decreasing axial loads In boxes are applied straight gears.

Cam boxes are used on small-sector sports and modified cars. Serial products are not equipped with such aggregates.

Set of cam gears for the subaru box

Modes of operation of automatic transmissions

To select a box operation mode, a selector that is associated with is used. The box has a switching mechanism that is responsible for turning on the modes. Around the selector is installed frame with applied icons denoting operation mode. Icons can be equipped with backlight. The photo shows the basic version of the selector without the possibility of manual switching.

Typical scheme of switching and control modes

Basic functional

During the operation of the automatic box, several main modes are used, the features of which are discussed below.

The driver should know the features of the work and control of each regime:

1. Parking (P, Parking), applied during the location of the car in the parking lot, while the regime is not a parking brake. Inclusion is made only after stopping the machine. In the process of movement, the Enable Mode cannot be enabled because there is a special blocker in the switching mechanism device. Parking mode allows you to start the power unit starter, the wheels are connected to the box shafts by the locking mechanism hosted in the box crankcase.
2. Reverse (R, Reverse), used for maneuvering reverse. It turns on after the full stop of the vehicle. The selector has a blocking element that prevents accidental switching in motion.
3. Neutral position (N, NEUTRAL), in which the transmission is not included in the box. Difference from parking is the disabled wheel lock. It is allowed to start the engine. Towing on neutral mode is prohibited because the box does not supply fluid under pressure.
4. Movement mode (D, Drive), which is used to move the car. When you turn on the mode occurs automatic switching Speed \u200b\u200bup and down. On some transmissions, an additional L (LOW mode is used, which limits the inclusion of increased gear and is used when driving in complex road conditions.

Many manufacturers do not recommend leaving the car on the slopes with the hold only by the box, as this leads to deformation and stirring the blocking mechanism. When the car is stopped, the neutral position of the box selector is first installed, and then the manual brake lever rises. When touching the car is held manual brakethen the box is translated into the position and only then removed parking brake.

On special modes

Special or additional modes are used to operate the car in off-road conditions or to change the nature of the transmission, taking into account the specifics of the movement. Control of additional modes is performed by buttons or translating the switching lever to a separate position.

"Tittronic" mode

The name of the "Tittronic" regime (TipTronic) first appeared on the Porsche brand cars in 1990. The mode allows you to switch the speed of the automatic gearbox manually.

Developing the principle of Tiptronic Designers sought to connect in one unit the comfort of automatic transmission and dignity mechanical. In manual switching mode, the driver can control the car dynamics in braking modes force aggregate. There is also the possibility of forced transition to reduced transmission before entering or in the process of entering the turn.

Manual mode is used to provide additional acceleration during acceleration. The minus use of Tiptronic mode is the complication of the design of the box and delay when switching speeds that can reach one second.

For manual switching, the selector will be left left

Switching is performed or selector box switched to mode manual control Transmission. When controlling the lever, it is translated into the D position, and then the Block, in a separate series, indicated by the symbolism "+" and "-". The "+" icon denotes the direction of movement of the lever to turn on the increased transmission, the "-" icon is for reduced. The transmission number is displayed on the display located on the instrument combination.

Stealing petals switching

Designation of submissive petals is similar. One is used to switch the speeds up, the second - down.

The manual switching mode of the automatic speeds can be called STEPTronic - branded name from concern BMW.. Cardinal differences in the algorithm of work and management from TipTronic.

Sports modes

The inclusion of sports activates the special speed switch algorithm - on increased turns Engine. A number of manufacturers vehicle We use in the algorithm of operation a power unit control unit that provides a more intense set of revolutions. When removing the legs from the gas pedal, the turns fall after a while, which makes it possible to ensure the dynamics of overclocking when the pedal is reversed. On some cars, when you turn on the sports mode, the suspension stiffeners and the exhaust sound can be changed (using a special valve).

The Audi S5 selector, the activation of the sports mode is performed by the movement of the lever down until it stops

A special occasion of sports regime can be called "Kikdown", which is included with a sharp press on the gas pedal. In this case, switching to reduced transmission and more intensive car acceleration even when setting the switching selector in normal position.

Other modes

Depending on the manufacturer of the car and the box, additional modes may occur. Additional modes are controlled by moving the lever or press on separate buttons. Buttons are located on the lever or on the center console.

Overdrive, which is an additional increase. Function is used in some hydro mechanical boxes Transmissions.

Overdrive mode is an analogue of the fifth or sixth gear in the mechanical check boxes. When the mode is activated, switching to increased speed When the gas pedal is released, and when reverse pressing the box leaves one or more velocities down. With Overdrive disconnected, switching is performed on elevated circulation, when braking, transfer is held until the torque and speed drops to a certain value.

Overdrive is used in the steady movement of the car through country tracks without additional load (for example, trailer). The mode is indicated on the selector of the letter D or O / D.

Power button overdrive mode On the selector FORD FUSION.

The opposite of the Overdrive mode is the function of turning off the increased transmission. Denote in the selector with letters D3 or O / D OFF. It can be used when moving in urban conditions to ensure maximum speakers. In essence, it is an early sports regime.

D3 mode on selector

Winter MANU (S or Figures 1 or 2) is turned on with a button placed next to the selector lever. When you activate the mode, the switching speeds occurs on low engine speeds, which reduces the wheel slip on the snow-covered road and ice. It is possible to further decrease the slip by force the speeds of the speeds when starting from the place to the second gear. After the start of the movement, the box is translated into standard mode D. With an active winter mode, kikdown is possible, however it is limited by engine speed.

Well visible Button MANU, located right lever

Instructions how to use a box automatic

Brief instruction manual for automatic transmissions:

1. Start the engine.
2. Press and hold the brake pedal.
3. Translate the selector to the movement or reverse position.
4. Disable parking brake.
5. Let go of the brake, as the car will start smoothly move.
6. After the brake is completely released on gas to start moving. Gas reset leads to a braking engine and a reduction in speed.
7. To stop you need to click on the brake pedal.

Switching and automatic transmission modes

When operating the transmission, the lever switches in accordance with the recommendations set out above. When switching, you should not apply unnecessary effort to the lever. Difficult switching is a sign of a switch or cable drive.

Photo Gallery

The photo shows the features of the boxes on some cars. Management recommendations are available in operating instructions.

Features when managing a car with automatic transmission

There are no special differences in driving a car with automatic transmission. When moving, it is recommended to avoid frequent and sharp accelerations, as they lead to elevated heating and wear of the box.

Do you need a car with a manual brake box?

The car with automatic transmission must have a good parking brake. Holding a car in the parking lot only by transmission leads to high loads on the node that can cause damage.

How to use automatic traffic inspections?

With long-term depression in traffic jams, especially at high air temperature, it is recommended to periodically cool the unit. For this, the selector is translated into a neutral position, the car is held by work brakes.

With a long-term stop in a traffic jam, you can transfer the box selector to the parking position. In addition to cooling the transmission, this will give the opportunity to relax the driver, because it does not need to hold the brake pedal.

Steal switches

Steal switches are small-sized plastic levers, which are installed on the steering wheel and are connected through a flexible loop to electronic system car. When you click on the petals, manual switching speeds occurs.

Steering wheel Ford. with installed petals

Main conditions of operation automatic transmission

During the operation of the box, the owner must comply with a number of rules that prolong the resource of the unit. Especially it concerns winter operating. In addition, the box imposes some restrictions on operation, which must also be remembered and observed.

Operation of automatic box in winter

To warm up the box at a negative air temperature, it is necessary:

1. Start the engine and give it to work 2-3 minutes.
2. Getting behind the wheel, holding the leg brake to start translate the selector in all positions. Each position requires a delay of 8-10 seconds. It is recommended to warm the box for another 5-6 minutes, periodically translating the selector in a circle.
3. Start moving smoothly, not having a gas pedal by more than a third. Warm the box on smooth mode of movement for several kilometers of the way.

What should not be done with automatic transmission?

To ensure the resource of the box, the owner should not be made by the following manipulations:

1. Do not include a neutral position when moving in rolling, since in this case the grease and heat sink of the box nodes does not provide. The abuse of moving the movement can cause the wear and burning of friction discs and plates in the couplings.
2. It is forbidden to switch forward and backward modes without a complete stop of the car and rotating parts in the box. When switching, you must hold the car in the work brake. There are cases breakdown gears and crankcase boxes. It is for this reason that it is not allowed to get out of the dirt or snowy drift by swaying the car.
3. You can not use an automatic box as a parking brake.
4. You can not tow a car. Machines with automatic box are attached only with loading leading wheels on the tractor.
5. It is forbidden to give an increased load on the cold transmission. To warm up the box, more time is required than the engine heating, so the first 7-10 km of the path is recommended to move at low speed without jerks and accelerations.
6. Avoid roadless movement with wheel slip.
7. It is not recommended to use cars with automatic boxes for towing a heavy trailer.

Typical automatic transmission faults

Some common faults:

1. Diggers of switching scene, which do not allow switching operation modes. Repair is to replace broken or worn items. On some machines, access to the switching mechanism is difficult, so it may take a dismantling of a box or a subframe along with a power unit and a box.
2. Leak the working fluid through the glands or sealing pads. The problem is solved by replacing worn parts and change of fluid and filter.
3. Blocking the box work due to failure control electronics. During the repair process, blocks and wiring harnesses are changing.
4. The box does not allow moving forward, but reverse gear works. The reason is the wear of the couplings, jamming or clogging valves.
5. The rear gear does not work and part of the front turn gear. The cause of the breakage is the wear of one of the working couplings or a breakdown of hydraulic highways that ensure the operation of the node.
6. When trying to switch the selector and start the movement occurs, the mode switches, but the movement does not begin. This is a symptom of damage to the torque converter or an insufficient oil level. It is possible to clog the filter with wear products, which is why the necessary performance and pressure in hydraulic system boxes.
7. It is possible to move forward only at one speed. The reason is the worship of the couplings, the coupling of the cuft drive cuff, the blocking of the block valves.
8. Metal noises when moving point to wear bearings or gears. Rhythmic metal knock on idling Signals the wear of the disks in one of the couplings.
9. The problem with the movement of the car after warming up the box, while it works normally on the cold box. The defect arises as a result of wear or breakdowns of the blades on the impeller of the pump or turbine.

If there are problems with automatic box, the owner must contact specialized service. Attempts independent repair Can lead to irreversible consequences and the need to replace the box assembly.