Transmission car ( power train) ensures the transmission of forces (torque) from the engine to the drive wheels, as well as the transformation (transformation) of these forces depending on driving conditions. The transmission includes all the components and mechanisms of the car that connect the engine to the drive wheels.

It is necessary to distinguish between the transmissions of cars with rear axle drive (cars of a classic layout), with front wheel drive and all-wheel drive cars. Also, the transmission of an all-wheel drive vehicle designed for use in off-road conditions (SUV) will differ from the transmission of an all-wheel drive vehicle designed for paved roads.

The wheel formula of cars with rear or front wheel drive is written 4x2 (i.e., four wheels, two of which are driven). The wheel formula of a car with drive on the front and rear axle is written - 4x4 (i.e., four wheels - all driven).

Transmission mechanisms include: clutch, gearbox(including , transfer case And power take-off for auxiliary mechanisms) , cardan transmission, final drive, differential, drive wheel drives and some other mechanisms .

The final drive, gearbox and transfer case (if equipped) provide total gear ratio car transmission.

1). Clutch serves to connect the engine to the transmission, as well as to temporarily separate them (for example, at the time of gear shifting).

On cars, “dry”, single- or double-disc friction clutches with a mechanical (usually cable) or hydromechanical drive, as well as fluid couplings and torque converters are used.

The operation of friction clutches is based on the use of friction forces between solid surfaces, in particular between the clutch pressure plate, the friction linings of the driven clutch disc and the engine flywheel. Single-plate dry friction clutch device passenger car shown in drawing. Diagram of hydraulic and cable drive

Hydromechanical clutches and torque converters transmit torque from the engine to the transmission by exposing the working parts of the mechanism to fluid (usually special oil) circulating inside the torque converter housing. The torque converter design is shown in drawing. You can read about the operation of a simple torque converter Here.

2). Transmission serves to change the traction forces (torques) transmitted from the engine to the drive wheels, as well as to disconnect the engine from the transmission (including long-term) and ensure the vehicle moves in reverse.

The need to change the traction forces on the wheels arises when the driving conditions of the vehicle (road conditions) change. The greatest effort on the drive wheels is required when starting the car. When driving in difficult road conditions (for example, a steep climb or off-road), engine power will be spent on overcoming the resistance to vehicle movement. When driving in favorable road conditions (for example, a smooth highway), engine power can be “expended” to accelerate the car.

Depending on the driving conditions, the driver selects (engages) one or another gear in the gearbox, engaging gears with different gear ratios and, thereby, changing the torque on the drive wheels. IN automatic transmissions Gear control is carried out through inclusion control systems, without the direct participation of the driver.

When you change (increase/decrease) the torque on the drive wheels, their rotation speed changes in inverse proportion, by the same amount.

On modern automotive technology two are used - three-shaft gearboxes with simple gear transmission and external spur gears, as well as gears and reducers planetary type And variators. The number of forward gears can be in the range of 3 - 7, reverse - 1 - 2. Gear ratios are given in technical specifications transmission of a specific vehicle.

The general structure of a shaft mechanical gearbox can be viewed at rice.

The main parts of a shaft transmission are shafts (primary, secondary, intermediate), gears, synchronizers, bearings, parts of the gear shift mechanism (for “manual” boxes - forks, rods, etc.). Planetary gearboxes include shafts (drive, driven, central), a set of planetary gears consisting of a set of gears (satellite, sun and crown gears) and a carrier, friction-braking devices, a hydraulic or electro-hydraulic gear shift control mechanism.

The operation of a simple gear and planetary gear is discussed Here.

Transfer case has a device similar to a gearbox, is installed behind the main gearbox (sometimes, the gearbox and transfer case are structurally combined in one housing) and serves to distribute (distribute) force to all existing drive axles of the vehicle. The transfer case, as a rule, has two gears - high (direct) and low, which doubles the total number of gears and allows you to select transmission ratios for driving in severe off-road conditions. The box contains a mechanism for turning on/off one of the axles and a final drive with an interaxle differential, if permanent all-wheel drive is provided. There may also be a locking mechanism for the center differential.

3). Cardan transmission serves to transmit rotation from the gearbox ( transfer case) to the main gear of the drive axle at constantly changing angles of inclination and the distance between the axles of the vehicle (base).

The angle of inclination of the driveshaft must change due to the fact that the drive axle of the car is attached to the body (frame) through the suspension elements (i.e., not rigidly) and has a certain degree of freedom. For the same reason, the distance between the axles of the car also changes. So, when accelerating a car, the rear drive axle tends to “catch up” with the front part of the body, and when braking, on the contrary, “lag behind” it.

A cardan transmission may consist of one or more shafts, cardan joints, elastic connecting and suspension couplings.

You can see the device of the cardan transmission of a passenger car .

4). Main gear transmits torque at an angle of 90º from the driveshaft to the drive wheels, changes the torque in accordance with its gear ratio.

There are single and double main gears. Gears can be bevel and/or cylindrical. Single simple gears consist of a driving and driven gear. The driving small gear is a bevel gear with spiral teeth, installed in rolling bearings and driven from the cardan shaft, or directly from the gearbox shaft. The driven large gear, with spiral teeth, is bolted to the differential box. In hypoid gears, the axis of the small bevel gear is shifted downward relative to the axis of the large driven gear by 30 - 40 mm.

Hypoid gears are manufactured in “pairs” and marked. Replacement of gears should only be carried out as a set.

The final drive device is shown in drawing.

e). Differential distributes torque between the drive wheels (axles) and allows the drive wheels of the car to rotate at different speeds, which is necessary when the car corners and when the wheels encounter different road conditions (for example, one wheel is on a flat surface, and the second is moving on uneven surfaces).

Differentials with bevel gears are most widely used. The differential has a housing (differential box) in which bevel side gears and satellite gears mounted on the axle are located.

The above property of the differential, in the case of differences in the adhesion of the drive wheels to the road surface, often leads to slipping of one of the wheels (the wheel with a lower coefficient of adhesion to the road). To eliminate this undesirable effect on machines off-road differentials are used high friction(self-locking differentials) or use differential locking mechanisms.

The differential structure is shown in drawing.

5). Wheel drives.

The drive axle shafts are installed in the axle sleeves of the drive axle beam and serve to transmit rotation from the differential to the wheels. According to operating conditions, axle shafts are divided into two main types: half-unloaded And completely unloaded.

The semi-loaded axle shaft lies at one end in the differential box, and at the other end in the axle shaft bearing.

The fully unloaded axle shaft lies at one end in the differential box, and at the other, through a flange, it is connected to the wheel hub. In turn, the wheel hub on bearings is installed at the end of the axle sleeve. With this installation, the axle shaft transmits only torque. All other forces are perceived by the drive axle beam through the bearings.

The drive axle is a common casing (beam) with a central crankcase and semi-axial sleeves. The crankcase houses the main gear and differential. Axle shafts are installed in semi-axial sleeves.

The front wheel drives contain such an element as constant velocity joint, ensuring uniform rotation of the wheels at their different spatial positions when turning the car.

The rear wheel drive of a classic car is shown , front wheel drive is shown in drawing. You can read about the constant velocity joint Here.

40 41 42 43 44 45 46 47 48 49 ..

Wheel drive of drive axles of MAZ-64227, MA3-54322 vehicles

(Fig. 57). It is a planetary gearbox consisting of spur gears with external and internal gearing. From the drive gear of the wheel transmission, rotation is transmitted to four satellites 14, evenly spaced in a circle around the drive gear.

The satellites rotate on axles 10, fixed in the holes of the movable carrier 12, connected with bolts to the hub of the drive wheels, in the direction opposite to the direction of rotation of the drive gear. Rotating on their axes, the satellites roll along the teeth
internal gearing of the driven gear 15, fixedly fixed by means of a hub 16 on the splined end of the axle beam axle.

The drive gear has a hole with involute splines that mate with the splines of the outer shaft of the axle shaft. The axial movement of the drive gear on the axle shaft is limited by a spring lock ring. The axial movement of the axle shaft is limited by the block 7 and the axle shaft stop 8. The satellites with needle bearings are mounted on an axle, placed in the coaxial holes of the carrier (2 and secured in it from axial movement by spring lock rings. On the satellite axis washers are put on to prevent the gears and bearings of the satellite axles from touching the carrier.

The driven gear 15 of the wheel transmission rests with its internal gear ring on the external gear ring of the hub 16 of the driven gear, and the splined end of this hub is mounted on the splined part of the axle beam axle. Such a connection does not allow rotation of the driven gear, but its axial movement is limited by a spring ring that fits into the groove of the driven gear ring gear and abuts against the inner end of the hub gear ring 16.

The satellite axles are equipped with washers to prevent the gears and bearings of the satellite axles from touching the carrier. The carrier is closed from the outside with a cover 9 and, in conjunction with the wheel hub, is sealed with a rubber ring 13.

The gears and bearings of the wheel drive are lubricated with sprayed oil, which is poured through a hole in the cover 9, closed with plug 5. The lower edge of this hole determines the required oil level in the wheel drive. Drain hole, closed by plug 3, is made in the wheel hub, since the cavities of the wheel drive and the wheel hub communicate.

When the car moves, the oil in the wheel drive cavity and wheel hubs is mixed and supplied to the gear bearings, wheel hubs and gears. To improve the supply of lubricant to the bearings of the satellite axles, the axles are made hollow and have radial holes in them for supplying oil to the bearings.

The main gear of the MAZ-64227 middle drive axle consists of a central gearbox and planetary wheel gears located in the wheel hubs.

Rice. 57. Wheel drive

The transmission in the design of the car ensures the change and transmission of rotation from power plant to the drive wheels. This component includes a number of components, including the main transmission of the car.

Purpose, design features

The main task of this element is to change the torque before applying it to the wheel drive. The gearbox does the same, but it has the ability to change gear ratios by engaging certain gears. Despite the presence of a gearbox in the design of the car, the torque output from it is small, and the rotation speed of the output shaft is high. If you transfer rotation directly to the drive wheels, the resulting load will “crush” the engine. In general, the car simply will not budge.

The final drive of the car provides increased torque and reduced rotation speed. But unlike a gearbox, its gear ratio is fixed.

The location of the final drive using the example of a conventional manual transmission

This transmission on a passenger car is a conventional single-stage constant mesh gearbox, consisting of two gears of different diameters. The drive gear is small in size and is connected to the gearbox output shaft, that is, rotation is supplied to it. The driven gear is much larger in size and it supplies the resulting rotation to the drive shafts of the wheels.

The gear ratio is the ratio of the number of gear teeth in the gearbox. For passenger cars this parameter is in the range of 3.5-4.5, and for trucks it reaches 5-7.

The higher the gear ratio (the greater the number of teeth on the driven gear relative to the drive gear), the higher the torque supplied to the wheels. In this case, the tractive effort will be greater, but the maximum speed will be lower.

The main gear ratio is selected based on operational indicators power plant, as well as other transmission components.

The final drive design directly depends on the design features of the car itself. This gearbox can be like separate unit, installed in its crankcase (rear-wheel drive models), and be included in the design of the gearbox (vehicles with front-wheel drive).

Final drive in a rear-wheel drive car

As for some all-wheel drive cars, they may use a different layout. If in such a car the location of the power plant is transverse, then the main gear of the front axle is included in the design of the gearbox, and the rear axle is located in a separate housing. In a car with a longitudinal layout, the main gears on both axles are separated from the gearbox and transfer case.

In models with a separate main gear, this gearbox performs one more task - it changes the angle of rotation by 90 degrees. That is, the gearbox output shaft and wheel drive shafts are perpendicular.

Audi front axle final drive location

In front-wheel drive models, where the main gear is included in the gearbox design, these shafts are parallel, since there is no need to change the direction angle.

In a number trucks Two-stage gearboxes are used. It is noteworthy that their design can be different, but the most widespread is the so-called spaced layout, which uses one central gearbox and two wheeled (on-board) gearboxes. This design allows you to significantly increase the torque and, accordingly, the traction force on the wheels.

The peculiarity of the gearbox is that it evenly divides the rotation between both drive shafts. For straight-line motion, this condition is normal. But when cornering, the wheels of the same axle travel different distances, so it is necessary to change the rotation speed of each of them. This is the job of the differential used in the transmission design (it is installed on the driven gear). As a result, the main gear supplies rotation to the drive shafts not directly, but through the differential.

Types and their applicability

The main characteristic of the main gears is the type of gears and the type of tooth engagement between them. The following types of gearboxes are used on cars:

1. Cylindrical
2. Conical
3. Hypoid
4. Worm

Main gear types

Spur gears are used in the final drives of front-wheel drive cars. The absence of the need to change the direction of rotation allows the use of such a gearbox. The teeth on the gears are oblique or chevron.

The gear ratio for such gearboxes is in the range of 3.5-4.2. A larger gear ratio is not used, since this requires increasing the size of the gears, which is accompanied by an increase in the noise level of the transmission.

Conical, hypoid and worm gear are used where it is necessary not only to change the gear ratio, but also to change the direction of rotation.

Bevel gearboxes are usually used on trucks. Their peculiarity comes down to the fact that the gear axes intersect, that is, they are at the same level. In such gears, oblique or curved teeth are used. This type of gearbox is not used on passenger cars due to significant overall dimensions and increased noise.

On rear-wheel drive cars, a different type is most often used - hypoid. Its peculiarity is that the gear axes are shifted. Due to the location of the drive gear lower relative to the driven axis, it is possible to reduce the dimensions of the gearbox. Moreover, this type of transmission is characterized by increased resistance to loads, as well as smooth and silent operation.

Worm gears are the least common and are practically not used on cars. The main reason for this is the complexity and high cost of manufacturing the components.

Basic requirements. Current trends

The main gears are subject to many requirements, the main ones being:

• Reliability;
• Minimal maintenance required;
• High efficiency indicators;
• Smooth and silent;
• Minimum possible overall dimensions.

Naturally, ideal option does not exist, so designers have to make compromises when choosing the type of final drive.

It is not yet possible to abandon the use of final drives in transmission designs, so all developments are aimed at improving performance indicators.

It is noteworthy that changing the operating parameters of the gearbox is one of the main types of transmission tuning. By installing gears with a changed gear ratio, you can significantly influence the dynamics of the car, maximum speed, fuel consumption, load on the gearbox and power unit.

Finally, it is worth mentioning the design features robotic gearboxes with a double clutch, which also affects the final drive design. In such gearboxes, paired and unpaired gears are separated, so there are two secondary shafts at the output. And each of them transmits rotation to its own drive gear of the main gear. That is, in such gearboxes there are two driving gears, and only one driven gear.

DSG gearbox diagram

This design feature allows you to make the gear ratio on the gearbox variable. To do this, only drive gears with different numbers of teeth are used. For example, when using a number of unpaired gears, to increase traction, a gear is used that provides a larger gear ratio, and the gear of a paired row has a lower value of this parameter.

General structure and operating principle of a passenger car according to the block diagram

The composition and operating principle of modern passenger cars, front-wheel drive, rear-wheel drive and all-wheel drive, are generally the same.

The block diagram of a rear-wheel drive car is shown in Fig. 6.1.1.

The car includes:

• engine 1;
• power train or, which includes: clutch 5, gearbox 7, cardan transmission 8, main gear and differential 11, axle shafts 10;

Rice. 6.1.1. Block diagram of a rear-wheel drive car: 1 - engine; 2 - fuel pedal; 3 - generator; 4 - clutch pedal; 5 - clutch; 6 - gear shift lever; 7 - gearbox; 8 - cardan transmission; 9 - wheel; 10 - axle shafts; 11 - main gear and differential; 12 - parking (hand) brake; 13 - main brake system; 14 - starter; 15 - power supply from battery; 16 - suspension; 17 - steering; 18 - hydraulic main

• chassis, which includes: front and rear suspension 16, wheels and tires 9;
• governance mechanisms, consisting of steering 17, main 13 and parking 12 brake system;
• electrical equipment, which includes sources of electric current (battery and generator), electrical consumers (ignition system, starting system, lighting and alarm devices, instrumentation, heating and ventilation systems, windshield wiper, windshield washer, etc.);
• monocoque body.

U front wheel drive cars There is no cardan transmission or driveshaft box in the body, so the interior becomes more spacious and comfortable, and the vehicle weighs less.

Engine 1 (Fig. 6.1.1) - a machine that converts any type of energy (gasoline, gas, diesel fuel, charge of electricity) into the rotational energy of a cranked engine.

Most modern cars have piston engines internal combustion (ICE), in which part of the energy released during the combustion of fuel in the cylinder is converted into mechanical work rotation crankshaft(Fig. 6.1.2).

Displacement is a unit of measurement of engine volume equal to the product of the piston area by the length of its stroke and the number of cylinders. Displacement characterizes the power and size of the engine, expressed in liters or cubic centimeters.

To change quantity fuel mixture, supplied to the cylinder (to change engine power), is the fuel pedal (gas pedal) 2.

Rice. 6.1.2. Appearance modern engine: 1 - valve box cover; 2 - neck plug for filling oil into the engine; 3 - cylinder head; 4 - pulleys; 5 -drive belt; 6 - generator; 7 - crankcase; 8 - pallet; 9 - exhaust manifold

A flywheel with a toothed ring is installed on the crankshaft, which is the drive 5.

Clutch 5 provides a permanent mechanical connection between the engine and the gearbox and is designed to temporarily disable it for the time required to engage or shift gears.

The clutch (Fig. 6.1.3) consists of two friction clutches 1 and 3, pressed against each other by a spring 4. Drive disk 1 is mechanically connected to crankshaft engine, driven disk 3 - with gearbox drive shaft 14.

The clutch is turned on and off by the driver using pedal 8 (when the pedal is pressed, the clutch is disengaged). When you press the pedal, clutch discs 1 and 3 diverge, drive disc 1, connected to engine 13, rotates, but this rotation is not transmitted to driven disc 3 (the clutch is disengaged). The clutch must be disengaged during the period of engaging or shifting gears to ensure a shock-free connection of the gears in the gearbox.

When the pedal is smoothly released, the drive and driven discs engage smoothly. At the same time, due to slipping, the driving disk smoothly imposes rotation on the driven disk. It begins to rotate, transmitting torque to the input shaft of gearbox 14. Thus, the car can start moving smoothly from a standstill or continue moving in a new gear.

The gearbox is used to change the magnitude and direction of torque and transmit it from the engine to the drive wheels, as well as for long-term disconnection of the engine from the drive wheels while the car is parked.

The gearbox can be mechanical (with manual gear shift) or automatic (torque converter, robotic or CVT).

Rice. 6.1.3. Clutch diagram: 1 - flywheel; 2 - clutch driven disc; 3 - pressure disk; 4 - spring; 5 - release levers; 6 - release bearing; 7 - clutch release fork; 8 - clutch pedal; 9 - clutch master cylinder; 10 - hydraulic fluid; 11 - pipeline; 12 - clutch slave cylinder; 13 - engine; 14 - gearbox drive shaft; 15 - gearbox

Manual gearbox (Fig. 6.1.4) is a gearbox with a stepwise variable gear ratio.

It contains:

• crankcase 12, which contains oil 13 for lubricating rubbing parts;
• input shaft 2 connected to clutch driven disc 1
• input shaft gear 3, which is permanently connected to the intermediate shaft gear;
• intermediate shaft 4 with a set of gears of different diameters;
• a secondary shaft 9 with a set of gears that can be moved using the gear shift fork 6;
• gear shift mechanism 8 with shift lever 7;
• synchronizers are devices that ensure equalization of gear rotation speeds during gear changes.

The driver changes gears using shift lever 7. Since the gearbox of a modern car has a large set of gears, by engaging different pairs of gears (when engaging any gear), the driver also changes the overall gear ratio (gear ratio). The lower the gear, the lower the vehicle speed, but the greater the torque and vice versa.

When the engine is running, before turning on or shifting gears in a manual transmission, in order to shift gears without shock, you need to depress the clutch pedal (disengage the clutch).

Rice. 6.1.4. Manual gearbox: 1 - clutch; 2 - input shaft; 3 - drive gear; 4 - intermediate shaft; 5 - secondary shaft gear; 6 - gear shift fork; 7 - gear shift lever; 8 - switching device; 9 - secondary shaft; 10 - cross; 11 - cardan transmission; 12 - crankcase; 13 - gearbox oil

The most common gear shift patterns in passenger cars are shown in Fig. 6.1.5.

Rice. 6.1.5. The most common gear shift patterns in passenger cars are 1 and 2, 3 and 4 - using the gear lever

In automatic gearbox(Fig. 6.1.6) includes:

• The torque converter (2, 5, 4, 5, 9), which is directly connected to the engine, is filled with hydraulic fluid 10. The fluid is the medium for transmitting torque from the engine to the manual transmission. The principle of operation is as follows: with increasing engine speed, the revolutions of shaft 2 with blades 3 increase, which cause rotation of the hydraulic fluid 10. The rotating fluid begins to put pressure on the blades of the secondary shaft 4 and causes rotation of the secondary shaft. The torque converter essentially acts as a clutch;
• manual transmission Gear 7 receives rotation from the torque converter, gear shifting in it is carried out by servo drives according to commands from control unit 6.

Rice. 6.1.6. Automatic gearbox: 1 - engine; 2 - input shaft; 3 - blades of the input shaft; 4 - secondary shaft blades: 5 - secondary shaft; 6 - automatic transmission control unit; 7 - manual gearbox; 8 - output shaft

To control an automatic, robotic or CVT transmission, use the gear selector (Fig. 6.1.7).

Rice. 6.1.7. Typical schemes selectors automatic boxes gear shift:

P - parking, mechanically blocks the gearbox; R- reverse, should only be turned on after the vehicle has come to a complete stop; N - neutral, in this position you can start the engine; D - drive, forward movement; S (D3) - range low gears, turns on on roads with slight inclines. Engine braking is more effective than in position D; L (D2) - second range of low gears. Turns on on difficult road sections. Engine braking is even more effective

Cardan transmission(in the back and four-wheel drive vehicle) allows you to transmit torque from the gearbox to rear axle(main gear) when the vehicle is driving on an uneven road (Fig. 6.1.8).

Rice. 6.1.8. Cardan transmission: 1 - front shaft; 2 - cross; 3 - support; 4 - cardan shaft; 5 - rear shaft

Main gear 5 serves to increase torque and transmit it at right angles to axle shaft 6 of the vehicle (Fig. 6.1.9).

Differential ensures rotation of the drive wheels at different speeds when the car turns and the wheels move on uneven roads.

Half shafts 6 transmit torque to the drive wheels 7.

Chassis ensures movement and smoothness. It includes a subframe, usually combined, to which through the front and rear suspension elements of the front and rear axles with hubs and wheels 7.

Mechanisms and parts of the chassis connect the wheels to the body, dampen its vibrations, perceive and transmit forces acting on the car.

While inside a passenger car, the driver and passengers experience slow vibrations with large amplitudes and fast vibrations with small amplitudes. Soft seat upholstery, rubber engine mounts, gearboxes, etc. protect against fast vibrations. Elastic suspension elements, wheels and tires protect against slow vibrations.

Rice. 6.1.9. Rear-wheel drive car: 1 - engine; 2 - clutch; 3 - gearbox; 4 - cardan transmission; 5 - main gear; 6 - axle shaft; 7 - wheel; 8 - leaf spring suspension; 9 - spring suspension; 10 - steering

The suspension (Fig. 6.1.10) is designed to soften and dampen vibrations transmitted from road irregularities to the car body. Thanks to the wheel suspension, the body makes vertical, longitudinal, angular and transverse angular vibrations. All these vibrations determine the smoothness of the car. The suspension can be dependent or independent.

Dependent suspension (Fig. 6.1.10), when both wheels of one vehicle axle are connected to each other by a rigid beam (rear wheels). When one of the wheels hits an uneven road, the other one tilts at the same angle. Independent suspension when the wheels of one axle of the car are not rigidly connected to each other. When hitting an uneven road, one of the wheels may change its position, but the position of the second wheel does not change.

Rice. 6.1.10. Diagram of operation of dependent (a) and independent (b) car wheel suspension

An elastic suspension element (spring or spring) serves to soften shocks and vibrations transmitted from the road to the body.

Rice. 6.1.11. Shock absorber diagram:

1 - car body; 2 - rod; 3 - cylinder; 4 - piston with valves; 5 - lever; 6 - lower eye; 7 - hydraulic fluid; 8 - upper eye

The damping element of the suspension - the shock absorber (Fig. 6.1.11) - is necessary to dampen body vibrations due to the resistance that occurs when fluid 7 flows through calibrated holes from cavity “A” to cavity “B” and back (hydraulic shock absorber). Gas shock absorbers can also be used, in which resistance occurs when gas is compressed. Stabilizer lateral stability The car is designed to improve handling and reduce vehicle roll when cornering. When turning, the car body presses one side of it to the ground, while the other side wants to go “away” from the ground. It’s the anti-roll bar, which, pressing one end to the ground, presses the other side of the car with the other, preventing him from getting away. And when a wheel hits an obstacle, the stabilizer rod twists and tries to return this wheel to its place.

Rice. 6.1.12. Steering diagram of the “gear-rack” type: 1 - wheels; 2 - rotary levers; 3 - steering rods; 4 - steering rack; 5- gear; 6-wheel steering

Steering(Fig. 6.1.12) serves to change the direction of movement of the car using the steering wheel. When the steering wheel 6 rotates, the gear 5 rotates and moves the rack 4 in one direction or another. When moving, the rack changes the position of the rods 3 and the associated rotary levers 2. The wheels turn.

Rice. 6.1.13. Brake system: main - 1-6 and parking (manual) -7-10. Actuating brake devices: A-disc; B - drum type; 1 - main brake cylinder; 2 - piston; 3 - pipelines; 4 - hydraulic brake fluid; 5 - rod; 6 - brake pedal; 7 - lever hand brake; 8 - cable; 9 - equalizer; 10 - cable

Brake system(Fig. 6.1.13) serves to reduce the speed of rotation of the wheels due to friction forces arising between brake pads 11 and brake drums A or discs B, as well as to hold the car stationary in parking lots, on descents and ascents using the manual brake system (7-10). The driver controls the brake system using the brake pedal 6 of the main brake system and the parking-night (hand) brake lever 7.

The main brake system (1-6), as a rule, is multi-circuit, that is, when you press the brake pedal 6, the pistons 2 move, the hydraulic pressure brake fluid 4 through pipelines 3 is transmitted to the executive braking devices A - for braking the front wheels and brake actuators B - for braking rear wheels. Systems A and B are independent of each other. If one circuit of the brake system fails, the other will continue to perform the braking function, although less effectively. The multi-circuit braking system increases traffic safety.

But now it wouldn’t be a bad idea to think about it! How does it move on the ground, our favorite car? We already know how the engine works, but the wheels spin in the other direction, and even forward and backward. And today we’ll talk about the transmission and its structure. What is included in the transmission and about design features this system.

In short, all the mechanisms that are located between the engine and the drive wheels are the car’s transmission. It performs the following functions:

• transmits torque from the engine to the drive axle;
• changes the value and direction of the torque;
• distributes torque over the drive wheels.

What is included in a car transmission and what are its types?

Depending on what type of energy is converted, this type of transmission can be:

• mechanical (converts and transmits mechanical energy);
• electrical (converts mechanical energy into electricity, and after supplying it to the drive wheels, converts electrical energy back into mechanical);
• hydrostatic (converts mechanical energy into the energy of fluid movement, and after supplying it to the drive wheels, back - the energy of fluid movement into mechanical energy);
• combined or hybrid (combination of electromechanical and hydromechanical).

Most often in modern cars use the first option. If the torque change occurs automatically, then it is called automatic.

Design

The design of the device may involve the use of front and rear pairs of wheels as drive wheels.

If both leading ones are used back pair wheels, then the car turns out to be rear-wheel drive, and if it’s front-wheel drive, it’s front-wheel drive. If a car has 4x4 drive to both rear and front wheels, then it is all-wheel drive.

Auto with different types drives have their own transmission design, which often differs significantly in the composition of the elements and their design.

So in a rear-wheel drive car these are sequentially located elements: clutch, gearbox, cardan and final drives, differential, axle shafts.

Clutch

Serves for short-term disconnection of the engine from the transmission and subsequent smooth connection of these elements after shifting gears, as well as protecting parts from excess loads.

Changes torque, speed and direction of movement, and also disconnects the engine and transmission for a long time. Boxes are mechanical, and (torque converter - planetary gears)

Cardan transmission

It is needed to transmit the torque from the secondary shaft of the gearbox to the main gear shaft, which are at an angle relative to each other.

Main gear

The GP is necessary to increase the torque, change the direction and transfer it to the axle shaft. Typically, cars use a hypoid main gear (the gear teeth are not straight, as usual, but radial).

Differential

The differential distributes torque to the drive wheels and allows the axle shafts to rotate at different angular velocities as the vehicle turns.

CV joint

The transmission of a front-wheel drive car is equipped with constant velocity joints (CV joints for short) and drive shafts (half shafts).

The first ones are necessary to remove the torque from the differential and supply it to the drive axle. As a rule, these are 2 hinges for connection with the differential (the so-called internal hinges) and 2 more hinges for connection with the wheels (the so-called external hinges).

Between these hinges are the drive shafts.

Auto transmission with all-wheel drive involves various design options discussed earlier, which together form an all-wheel drive system.

It's that simple. Now you know what is included in the car’s transmission, and we just have to understand in detail how each of the transmission mechanism components works. Follow the publications and don’t skimp on your knowledge, share it with everyone.

And see you again on the blog pages.