Do you know what it's called wheel at racing car? Steering wheel! And in our cars, all that is a steering wheel ... Do you feel the difference? But let's leave Schumacher's Schumacher and talk about what is steering, or steering gear.

The steering system is used to control the car and ensure its movement in a given direction at the command of the driver. The system includes steering gear and steering gear. To imagine the operation of steering mechanisms different generations, we will divide the explanation into three parts, that is how many there are in the automotive industry.

Worm gear

It got its name because of the steering column drive system, namely the worm gear. The steering system includes:

• steering wheel (I think it is not necessary to explain?)
• steering shaft with cross, is a metal rod, which has slots for fixing the steering wheel on one side, and internal slots for attaching to the steering column on the other. Full fixation is carried out by a turnbuckle, which compresses the junction of the shaft and the “worm” of the column drive. At the bend of the shaft, it is installed, with the help of which the lateral force of rotation is transmitted.
• steering column, a device assembled in one cast housing, which includes a worm drive gear and a driven one. The driven gear is rigidly connected to the steering arm.
• steering rods, tips and "pendulum", the totality of these parts connected to each other by means of ball and threaded joints.

The operation of the steering mechanism is as follows: when the steering wheel is rotated, the rotational force is transmitted to the worm gear of the column, the "worm" rotates the driven gear, which in turn drives the steering arm. The bipod is connected to the middle steering rod, the second end of the rod is attached to the pendulum lever. The lever is mounted on a support and is rigidly attached to the car body. Side rods depart from the bipod and the “pendulum”, which are connected to the steering tips with the help of crimp couplings. The tips are connected to the hub. The steering arm, turning, transfers the force simultaneously to the lateral thrust and to the middle lever. The middle lever actuates the second lateral link and the hubs turn, respectively the wheels too.

Such a system was common on old Zhiguli and BMW models.

Rack and pinion steering

The most common system at present. The main nodes are:

• steering wheel (steering wheel)
• steering shaft (same as in the worm gear)
• The steering rack is an assembly consisting of a toothed rack, which is driven by a steering gear. Assembled in one body, often made of light alloy, it is attached directly to the car body. At the ends of the gear rack, threaded holes are made for attaching steering rods.
• Tie rods are a metal rod with a thread on one end and a threaded swivel ball device on the other.
• steering tip, this is a body with a ball joint and an internal thread, for screwing in the steering rod.

When the steering wheel is rotated, the force is transferred to the gear, which drives steering rack. The rail "leaves" the body to the left or right. The force is transmitted to the steering lever with a tip. The tip is inserted into the hub, which it turns in the future.

To reduce the effort of the driver when turning the steering wheel, in the rack and pinion steering gear power steering was introduced, we will dwell on them in more detail

The power steering is an auxiliary device for turning the steering wheel. There are several types of power steering. This hydraulic booster, hydroelectric booster, electric booster and pneumatic booster.

1. The hydraulic booster consists of a hydraulic pump, which drives, a high-pressure hose system, and a fluid reservoir. The rack housing is hermetically sealed, as it contains hydraulic fluid. The principle of operation of the hydraulic booster is as follows: the pump builds up pressure in the system, but if the steering wheel is in place, the pump simply circulates the fluid. As soon as the driver begins to turn the steering wheel, the circulation is blocked, and the liquid begins to put pressure on the rail, “helping” the driver. The pressure is directed in the direction in which the "steering wheel" rotates.
2. V hydroelectric booster the system is exactly the same, only the pump rotates the electric motor.
3. V electric booster an electric motor is also used, but it is connected directly to the rack or to the steering shaft. Controlled electronic unit management. The electric power steering is also called an adaptive power steering due to the possibility of applying different forces to the rotation of the steering wheel, depending on the speed. The famous Servotronic system.
4. Pneumatic booster this is a close “relative” of the hydraulic booster, only the liquid has been replaced with compressed air.

Active steering system

The most "advanced" at the present time, it includes:

• steering rack with and electric motor
• electronic control unit
• steering rods, tips
• steering wheel (well, what about without it?)

The principle of operation of the steering system reminiscent of something. When the steering wheel rotates, the planetary mechanism rotates, which drives the rack, but that's just ratio always different, depending on the speed of the car. The fact is that the sun gear is rotated from the outside by an electric motor, therefore, depending on the speed of rotation, the gear ratio changes. At low speed, the transmission coefficient is unity. But with greater acceleration, when the slightest movement of the steering wheel can lead to negative consequences, the electric motor turns on, rotates the sun gear, respectively, it is necessary to turn the steering wheel more when turning. At low vehicle speeds, the electric motor rotates in the opposite direction, creating a more comfortable control.

The rest of the process looks like a simple rack system.

Haven't forgotten anything? Forgotten, of course! They forgot one more system - screw. True, this system is more like a worm gear. So - a screw thread is machined on the shaft, along which a kind of nut “creeps”, it is a gear rack with a thread inside. The rack teeth actuate the steering sector, in turn, it betrays the movement of the bipod, and then, as in the worm system. To reduce friction, there are balls inside the "nut" that "circulate" during rotation.

The steering mechanism includes a steering wheel, a shaft enclosed in a steering column, and a steering gear connected to the steering gear. The steering mechanism allows you to reduce the effort applied by the driver to the steering wheel to overcome the resistance that occurs when turning the steered wheels of the machine due to friction between the tires and the road, as well as soil deformation when driving on dirt roads.

The steering gear is mechanical transmission(for example, gear) installed in the housing (crankcase) and having a gear ratio of 15 - 30. The steering mechanism reduces the force applied by the driver to the steering wheel connected by means of a shaft to the gearbox, so many times. The greater the gear ratio of the steering gear, the easier it is for the driver to turn the steered wheels. However, with an increase in the gear ratio of the steering gear, in order to turn the steered wheel connected through the drive parts to the gear output shaft through a certain angle, the driver needs to turn the steering wheel at a larger angle than with a small gear ratio. When the vehicle is moving at high speed, it is more difficult to make a sharp turn at a large angle, since the driver does not have time to turn the steering wheel.

Steering gear ratio:

Up = (ap/ac) = (pc/pp)
where ap and ac are the angles of rotation, respectively, of the steering wheel and the output shaft of the gearbox; Рр, Рс - the force applied by the driver to the steering wheel, and the force on the output link of the steering mechanism (bipod).

So, to turn the bipod by 25° with a gear ratio of the steering gear equal to 30, the steering wheel must be turned by 750°, and with Up = 15 - by 375°. With a force on the steering wheel of 200 N and a gear ratio of Up = 30, the driver creates a force of 6 kN on the output link of the gearbox, and with Up = 15 - 2 times less. It is advisable to have a variable steering gear ratio.

At small steering angles (not more than 120°), a large gear ratio is preferable, which ensures easy and precise control of the car when driving at high speed. At low speeds, a small gear ratio allows, at small steering angles, to obtain significant steering wheel angles, which ensures high vehicle maneuverability.

When choosing the gear ratio of the steering mechanism, it is assumed that the steered wheels must turn from the neutral position to the maximum angle (35 ... 45 °) in no more than 2.5 turns of the steering wheel.

Steering mechanisms can be of several types. The most common of these are "worm-three-ridged roller", "worm-gear" and "screw-ball nut-rack-gear". The gear in the steering mechanism is made in the form of a sector.

The steering mechanism converts the rotational movement of the steering wheel into the angular movement of the steering arm mounted on the output shaft of the steering gear. The steering gear when driving a fully loaded vehicle, as a rule, should provide a force on the steering wheel rim of not more than 150 N.

The free steering angle (play) for commercial vehicles should generally not exceed 25° (corresponding to a shower length of 120 mm, measured at the steering wheel rim) when driving a commercial vehicle in a straight line. For cars of other types, the steering wheel play is different. Backlash occurs due to wear in operation of steering parts and misalignment of the steering mechanism and drive. To reduce friction losses and protect parts of the steering gear from corrosion, special gear oil is poured into its crankcase, mounted on the frame of the machine.

When operating the vehicle, it is necessary to adjust the steering mechanism. Adjusting devices of steering gears are designed to eliminate, firstly, the axial play of the steering shaft or the leading element of the gearbox, and secondly, the play between the driving and driven elements.

Consider the design of the steering mechanism of the type "globoidal worm - three-ridged roller".

Rice. Steering gear type "globoidal worm-three-ridged roller":
1 - steering gear housing; 2 - head of the steering arm shaft; 3 - three-ridged roller; 4 - shims; 5 - worm; 6 - steering shaft; 7 - axis; 8 - bipod shaft bearing; 9 - lock washer; 10 - cap nut; 11 - adjusting screw; 12 - bipod shaft; 13 - stuffing box; 14 - steering arm; 15 - nut; 16 - bronze bushing; h - adjustable depth of engagement of the roller with the worm

The globoidal worm 5 is installed in the crankcase 1 of the steering gear on two tapered roller bearings, which well perceive axial forces arising from the interaction of the worm with the three-ridged roller 3. The worm, pressed onto the splines at the end of the steering shaft 6, provides good engagement of the roller ridges with a limited length with worm cutting. Due to the fact that the action of the load is dispersed over several ridges as a result of their contact with the worm, as well as the replacement of sliding friction in engagement with much lower rolling friction, high wear resistance of the mechanism and a sufficiently high efficiency are achieved.

The axis of the roller is fixed in the head 2 of the shaft 12 of the steering arm 14, and the roller itself is mounted on needle bearings, which reduce losses when the roller is scrolled relative to the axis 7. The bearings of the steering arm shaft are, on the one hand, a roller bearing, and on the other, a bronze bushing 76. The bipod is connected to the shaft with the help of small slots and secured with a washer and nut 15. An oil seal 13 is used to seal the bipod shaft.

The engagement of the worm with the ridges is carried out in such a way that in the position corresponding to the rectilinear movement of the machine, there is practically no free play of the steering wheel, and as the angle of rotation of the steering wheel increases, it increases.

The steering shaft bearing tightening is adjusted by changing the number of gaskets installed under the crankcase cover, which rests with its plane against the end of the extreme tapered roller bearing. Adjustment of the engagement of the worm with the roller is carried out by shifting the shaft of the steering arm in the axial direction using the adjusting screw 11. This screw is installed in the side cover of the crankcase, closed from the outside with a cap nut 10 and fixed with a lock washer 9.

On heavy-duty vehicles, steering gears of the “worm-side sector (gear)” or “screw-ball nut-rack-gear” type are used, which have a large contact area of ​​the elements and, as a result, low pressures between the surfaces of the working pairs of the gearbox.

The worm-side sector steering mechanism, the simplest in design, is used on some cars. The side sector 3 is engaged with the worm 2 in the form of a part of a gear with helical teeth. The side sector is made as a single unit with the shaft 1 bipod. The bipod is located on a shaft mounted on needle bearings.

The gap in engagement between the worm and the sector is not constant. The smallest gap corresponds to the middle position of the steering wheel. The clearance in the engagement is regulated by changing the thickness of the washer located between the side surface of the sector and the steering gear housing cover.

The design of the steering mechanism of the "screw-ball nut-rail-sector" type is shown in the figure. The steering wheel shaft is connected by means of a cardan drive to the screw 4, which interacts with the ball nut 5, which is fixedly fixed by the lock screw 15 in the piston-rack 3. The thread of the screw and nut is made in the form of semicircular grooves filled with balls 7 circulating along the thread when the screw rotates. The extreme threads of the nut are connected by a groove 6 with an outer tube that ensures the circulation of the balls. The rolling friction of these balls along the thread during the rotation of the screw is insignificant, which determines the high efficiency of such a mechanism.

Rice. Steering gear type "worm-side sector":
1 - bipod shaft; 2 - worm; 3 - side sector

Rice. Steering gear type "screw-ball nut-rail-sector":
1 - cylinder cover; 2 - crankcase; 3 - piston rail; 4 - screw; 5 - ball nut; 6 - gutter; 7 - balls; 8 - intermediate cover; 9 - spool; 10 - control valve body; 11 - nut; 12 - top cover; 13 - plunger spring; 14 - plunger; 15 - locking screw; 16 - gear sector (gear); 17 - shaft; 18- bipod; 19 - side cover; 20 - retaining ring; 21 - adjusting screw; 22 - ball pin

When turning the car, the driver, using the steering wheel and shaft, rotates the screw, relative to the axis of which the ball nut moves on circulating balls. Together with the nut, the piston-rack also moves, turning the toothed sector (gear) 16, made as a single unit with the shaft 17. The bipod 18 is mounted on the shaft using splines, and the shaft itself is placed on bronze bushings in the crankcase 2 of the steering gear.

Even vehicles designed to travel on rails have steering gear. What can we say about a car, where the steering mechanism, given the need for an almost constant maneuver, the most unexpected and inadequate possible road condition, must be reliable and easily functional.

Purpose

The steering mechanism on a car is a gearbox, with the help of which a small force applied by the driver in the cab to the steering wheel, increasing, is transmitted to the steering gear. On heavy vehicles and recently on passenger cars, for greater ease of control, manufacturers install a hydraulic booster.

A properly functioning system must meet a number of basic requirements:

1. The gear ratio, which determines the ratio between the angle of rotation of the steering wheel and the wheels, must be optimal. It is unacceptable that in order to make a 900 turn, the steering wheel must be made 2-3 turns.
2. Upon completion of the maneuver, the steering wheel (steering wheel) must arbitrarily return to the neutral position,
3. A small backlash is allowed and provided.

Classification

Depending on the class of the car, its size, and other design solutions for a particular model, today there are three main types:

• worm;
• screw;
• gear.

Let's consider in order.

Worm

The first scheme is a worm gear. One of the most common schemes - "globoidal worm - roller" - is used mainly on buses and small cars. trucks, on the cars high cross-country ability and vehicles with dependent front wheel suspension. He was put on the domestic "Lada" (VAZ 2105, 2107).


The worm mechanism tolerates shocks from road bumps well and provides a greater angle of rotation of the wheels than the rack and pinion. However, a device of this type is quite expensive to manufacture and requires mandatory periodic adjustment.

screw gearbox

This type is most common on large trucks and heavy buses. They can also be equipped with such expensive cars as Range Rover, Mercedes and others. The most common scheme looks like this:

• screw;
• nut (ball);
• rail;
• gear sector.
• The screw gearbox can be either with a built-in hydraulic booster or without it. Possessing the same advantages as a worm, screw has a greater efficiency.

Gear or rack

The last type of gearbox is the most familiar to the mass Russian motorist. It is better known as a rack and pinion steering mechanism due to the presence of a horizontal gear rack in the device. This rack, through a gear on the steering wheel shaft, receives movement to the right or left and turns the wheels through the rods. The device is most widely used in passenger cars.


The rack-and-pinion steering mechanism is characterized by simple design, low weight and relatively low manufacturing cost. The rack and pinion steering mechanism includes a small number of rods and hinges and at the same time has a fairly high efficiency. Due to the increased rigidity, the car perfectly obeys the steering wheel. But for the same reason, the car is more sensitive to road bumps.

The rack and pinion steering mechanism can be installed on a car with or without power steering. However, due to design features it is difficult to mount it on cars with dependent front suspension. Because of this, its scope is limited only to passenger cars with independent suspension of the front steered wheels.

Care and prevention of the steering mechanism

A car is a single complex organism. The service life of components and parts in the device of the machine as a whole and the steering mechanism in particular depends on many factors. These include:

1. driving style of a particular person;
2. state of roads;
3. timely maintenance.

Whenever driving a car onto a flyover or descending into a viewing hole for any reason, pay attention to the condition of the protective rubber bands, levers and steering gear nuts. Nothing should hang out. Backlash in the drive joints is easy to check by shaking the wheel and listening to the work of the articulated parts.
Remember: prevention is the best cure.

Many will agree that the engine is the backbone of the car. And indeed it is. However, it is also difficult to imagine a car without steering. This is an important and necessary element in every car. The task of steering is to provide movement vehicle in the given direction. This node consists of several components. These are the steering wheel, column, drive and steering gear. We will talk about the latter today.

Functions

The steering mechanism has several main tasks:

• Transfer of forces to the drive.
• The increase in effort that is applied by the driver to the steering wheel.
• Independent return of the steering wheel to the neutral position when the load is removed.

Varieties

This element can be of several types. Today there are the following types of steering mechanisms:

• Rack.
• Worm.
• Screw.

What is each of them? We will consider all these types of mechanisms separately.

Rack

At the moment it is one of the most common. It is mainly installed on cars and crossovers. The rack and pinion steering mechanism requires the following parts:

The first was mounted on the steering shaft. The pinion is in constant mesh with the rack. Active this mechanism pretty simple. When the steering wheel is turned, the rack moves to the right or left. In this case, the rods that are attached to the drive turn the steered wheels at a given angle.

Among the advantages of such a mechanism, it is worth noting the simplicity of design, high efficiency and high rigidity. However, at the same time, such a mechanism is very sensitive to bumps in the road, which is why it wears out quickly. Often, used car owners are faced with the problem of a knocking rack. This is a consequence of the wear of the steering mechanism. Therefore, the element is installed only on certain types of cars. Basically, these are front-wheel drive cars with independent front suspension. If we talk about the VAZ, then the rail is found on all models, starting with the G8. On the "classic" a slightly different steering mechanism is installed.

Worm

It is this type that is used on domestic Zhiguli, as well as on some buses and light trucks. This node consists of:

• Worm of globoid type with variable diameter.
• The steering shaft to which the worm is connected.
• roller.

A bipod is located outside the steering mechanism. This is a special lever that is connected to the drive rods. The steering mechanism on the GAZ-3302 is arranged according to the same scheme.

Among the advantages of such a node, it is worth noting less sensitivity to shock loads. Therefore, this steering mechanism, installed on the VAZ-2107, is practically eternal. Owners rarely experience knocking and vibrations on the steering wheel. However, this design scheme has more connections. Therefore, periodically the mechanism needs to be adjusted.

Screw

This is a more complex node in the device. Its design includes:

• Screw. Located on the steering wheel shaft.
• Screw. It moves over the previous element.
• Rack.
• gear selector. It is connected to the rail.
• Steering column. Located on the selector shaft.

The key feature of this mechanism is the way the nut and screw are connected. Fastening is carried out using balls. Thus, less wear and friction of the pair is achieved.

The principle of operation of the screw element is similar to the worm. The steering wheel is turned by turning the screw, which moves the nut. The latter moves the gear sector with the help of the rack, and with it the steering arm.

Where is the screw mechanism used? Often, it is used on heavy commercial vehicles - trucks and buses. If we talk about cars, then these are just models executive class. The mechanism is more complex in design and expensive, and therefore significantly increases the cost of the car itself.

Amplifier

Now almost all cars use power steering. It serves to reduce the effort required to turn the front wheels. This element allows for high precision and speed of steering. At the moment, there are several types of amplifiers:

• Hydraulic.
• Electric.

The first type is more popular. Fits both cars and trucks. The amplifier device has a pump that creates a certain pressure in the hydraulic system. Depending on the side of the steering wheel, this fluid presses on the first or second rack circuit. Thus, the force required to turn is reduced. Benefits hydraulic system it is worth noting high reliability. The amplifier rarely fails. However, since the pump mechanism is driven by the crankshaft, some power is taken from the internal combustion engine. Although on modern engines it is not noticeable at all.

The electric booster consists of a separate motor. The torque from it is transmitted to the steering wheel shaft itself. The design is used only on passenger cars, as it is not designed for high efforts.

The EUR is equipped with separate electronics, which controls this engine. Sometimes the amplifier is understaffed with adaptive systems that are aimed at increasing safety when driving along the lane.

Among the innovative solutions, it is worth noting the system dynamic control from Audi. Here the gear ratio changes depending on the current vehicle speed. Thus, on high speeds the steering is hard and knocked down, and when parking it becomes light. The gear ratio is changed using a double planetary gear that is added to the shaft. Its body can rotate depending on the speed of the car.

Conclusion

So, we found out what this mechanism is. This is a very responsible node in the steering. Regardless of the type, it must be checked periodically. After all, losing control at speed is the most dangerous thing that can happen to a driver.

The following requirements apply to the steering mechanism:
- the optimal gear ratio, which determines the ratio between the required angle of rotation of the steering wheel and the force on it; - insignificant energy losses during operation (high efficiency);
- the possibility of spontaneous return of the steering wheel to the neutral position after the driver stopped holding the steering wheel in the turned position;
- slight gaps in the movable joints to ensure a small backlash or free play of the steering wheel;
- high reliability.

The most widespread on passenger cars today are rack and pinion steering mechanisms.

Rack and pinion steering mechanism without hydraulic booster:
1 - cover;
2 - insert;
3 - spring;
4 - ball pin;
5 - ball joint;
6 - emphasis;
7 - steering rack;
8 - gear

The design of such a mechanism includes a gear mounted on the steering wheel shaft and a gear rack associated with it. When the steering wheel is rotated, the rack moves to the right or left and, through the steering rods attached to it, turns the steered wheels.
The reasons for the widespread use of just such a mechanism in passenger cars are: simplicity of design, low weight and manufacturing cost, high efficiency, a small number of rods and hinges. In addition, the rack-and-pinion steering housing, positioned across the vehicle, leaves ample space in engine compartment to accommodate the engine, transmission and other vehicle components. Rack and pinion steering has high rigidity, which provides more precise control of the car during sharp maneuvers.
At the same time, the rack and pinion steering mechanism also has a number of disadvantages: increased sensitivity to shocks from road bumps and the transmission of these shocks to the steering wheel; a tendency to vibroactive steering, increased loading of parts, the difficulty of installing such a steering mechanism on vehicles with dependent steering wheel suspension. This limited the scope of application of this type of steering mechanisms only to passenger cars (with a vertical load on the steered axle up to 24 kN) with independent suspension steered wheels.

Power steering rack and pinion:
1 - liquid under high pressure;
2 - piston;
3 - liquid under low pressure;
4 - gear;
5 - steering rack;
6 - hydraulic booster distributor;
7 - steering column;
8 - hydraulic booster pump;
9 - reservoir for liquid;
10 - suspension element

Steering gear type "globoidal worm-roller" without hydraulic booster:
1 - roller;
2 - worm

Passenger cars with dependent steering wheel suspension, light-duty trucks and buses, and off-road cars are usually equipped with globoidal worm-roller steering gears. Previously, such mechanisms were also used on cars with independent suspension (for example, the VAZ-2105, -2107 family), but at present they have practically been replaced by rack and pinion steering mechanisms.
Mechanism type "globoidal worm-roller" is a type of worm gear and consists of a globoidal worm (a worm with a variable diameter) connected to the steering shaft and a roller mounted on the shaft. On the same shaft, outside the body of the steering gear, a lever (bipod) is installed, with which the steering gear rods are connected. The rotation of the steering wheel ensures that the roller rolls over the worm, the bipod swings and the steering wheels turn.
In comparison with rack and pinion steering mechanisms, worm gears are less sensitive to the transmission of shocks from road bumps, provide large maximum angles of rotation of the steered wheels (better vehicle maneuverability), fit well with a dependent suspension, and allow the transmission of large forces. Sometimes worm gears are used on high-end passenger cars and large dead weights with independent suspension of steered wheels, but in this case the design of the steering gear becomes more complicated - additional steering rod and pendulum lever are added. In addition, the worm gear requires adjustment and is expensive to manufacture.

Steering mechanism of the type "screw-ball nut-rack-toothed sector" without hydraulic booster (a):
1 - crankcase;
2 - screw with ball nut;
3 - shaft-sector;
4 - filler plug;
5 - shims;
6 - shaft;
7 - steering shaft seal;
8 - bipod;
9 - cover;
10 - shaft-sector seal;
11 - the outer ring of the bearing of the shaft-sector;
12 - retaining ring;
13 - sealing ring;
14 - side cover;
15 - cork;
with built-in hydraulic booster (b):
1 - adjusting nut;
2 - bearing;
3 - sealing ring;
4 - screw;
5 - crankcase;
6 - piston-rail;
7 - hydraulic distributor;
8 - cuff;
9 - sealant;
10 - input shaft;
11 - shaft-sector;
12 - protective cover;
13 - retaining ring;
14 - sealing ring;
15 - the outer ring of the bearing of the shaft-sector;
16 - side cover;
17 - nut;
18 - bolt

The most common steering mechanism for heavy trucks and buses is the "screw-ball nut-rack-toothed sector" mechanism. Sometimes steering mechanisms of this type can be found on large and expensive cars (Mercedes, range rover and etc.).
When the steering wheel is turned, the shaft of the mechanism with a helical groove rotates and the nut put on it moves. In this case, the nut having outside gear rack, turns the gear sector of the bipod shaft. To reduce friction in the screw-nut pair, forces are transmitted in it by means of balls circulating in the helical groove. This steering gear has the same advantages as the worm gear discussed above, but it has a high efficiency, allows you to effectively transfer large forces and is well combined with a hydraulic power steering.
Previously, other types of steering gears could be found on trucks, for example, “worm-side sector”, “screw-crank”, “screw-nut-rod-lever”. On the modern cars such mechanisms are practically not used due to their complexity, the need for adjustment and low efficiency.