Rice. 1

Steering gear worm type comprises:

steering wheel with shaft,

Carter worm pair,

Pairs of "worm-roller",

Pilot bipod.

In the crankcase of the steering mechanism, a pair of "worm-roller" is in constant engagement. The worm is nothing more than the lower end of the steering shaft, and the roller, in turn, is located on the steering arm shaft. When the steering wheel is rotated, the roller begins to move along the screw thread of the worm, which leads to the rotation of the steering arm shaft. Worm pair, like any other gear connection, requires lubrication, and therefore oil is poured into the crankcase of the steering mechanism, the brand of which is indicated in the instructions for the car. The result of the interaction of the "worm-roller" pair is the transformation of the rotation of the steering wheel into the rotation of the steering arm in one direction or another. And then the force is transferred to the steering drive and from it to the steered (front) wheels.

The steering gear used with the worm type mechanism includes:

Right and left side traction,

medium thrust,

pendulum lever,

Right and left wheel swivel arms.

Each Tie Rod has hinges at its ends so that the moving parts of the steering gear can freely rotate relative to each other and the body in different planes.

The advantages of the worm-roller mechanism include:

Low propensity to pass blows from road bumps

Large steering angles

Possibility of high power transfer

The disadvantages are:

A large number of rods and articulations with ever-accumulating backlash

- “heavy” and uninformative steering wheel

Difficulties in manufacturing technology

Steering gear type “screw-nut-sector”

Rice. 2 Steering gear type "screw - ball nut - rack - sector"

1 - distributor;

3 - balls with a recirculation tube;

4 - piston rail;

5 -- toothed sector;

6 - bipod shaft;

7 -- restrictive valve

The full name is "screw-ball nut-rail-sector". The screw 2, which ends the steering shaft, pushes the piston-rack 4 along its axis through the balls 3 circulating along the thread. And that, in turn, turns the gear sector 5 of the steering arm. Because of the ability to transmit big moments, installed on trucks, pickups and large SUVs working in extreme conditions.

Advantages of the “screw-ball nut-rack-sector” steering mechanism:

Possibility of high gear ratio design

Disadvantages of the steering mechanism “screw-ball nut-rail-sector”:

Non-technological

Expensive

Large dimensions

Heavy

Steering gear rack type

In the steering mechanism rack and pinion» power is transmitted to the wheels by a spur or helical gear mounted in bearings, and gear rack moving in guide bushings. To ensure backlash-free engagement, the rack is pressed against the gear by springs. The steering gear is connected by a shaft to the steering wheel, and the rack is connected to two transverse rods, which can be attached in the middle or at the ends of the rail. Full rotation of the steered wheels from one extreme position to the other is carried out in 1.75 ... 2.5 turns of the steering wheel. The gear ratios of the mechanism are determined by the ratio of the number of revolutions of the gear wheel, equal to the number of revolutions of the steering wheel, to the distance of movement of the rack.

The rack and pinion steering mechanism consists of a crankcase cast from an aluminum alloy. A drive gear is installed in the crankcase cavity on ball and roller bearings. Marks are made on the crankcase and on the anther for the correct assembly of the steering mechanism. The toothed wheel is engaged with the toothed rack, which is pressed against the toothed wheel by a spring through a ceramic-metal stop. The spring is pressed by a nut with a retaining ring, creating resistance to loosening the nut. The spring-loaded stop facilitates backlash-free engagement of the gear wheel with the gear rack over the entire stroke. The rail rests at one end on the stop, and at the other end on a split plastic sleeve. The travel of the rack is limited in one direction by a ring pressed onto the rack, and in the other direction by a bushing of the rubber-metal hinge of the left steering rod. The cavity of the crankcase of the steering mechanism is protected from contamination by a corrugated cover.

The steering shaft is connected to the drive gear with an elastic coupling. The upper part of the shaft rests on a deep groove ball bearing pressed into the bracket tube. On upper end shaft on the splines through the damping element is fastened with a nut steering wheel.

Variable ratio steering

Near the zero position of the steering wheel, when driving in a straight line at high speed, excessive steering sharpness is undesirable, it makes the driver tense up. And when parking or turning around, on the contrary, I would like to have gear ratio smaller - to turn the steering wheel at the smallest possible angle. To do this, there are several schemes of rack and pinion steering mechanisms.

This is how the ZF variable ratio rack and pinion steering works. Here the profile of the rack teeth and the gearing shoulder are changed

The Honda VGR (Variable Gear Ratio) rack and pinion steering was used on Honda cars NSX

The ZF company uses rack teeth with a variable profile: in the near-zero zone, the teeth are triangular, and closer to the edges, they are trapezoidal. The gear engages with them with a different shoulder, which helps to slightly change the gear ratio. And another, more complex, option was used by Honda on their NSX supercar. Here the rack and pinion teeth are made with variable pitch, profile and curvature. True, the gear has to be moved up and down, but the gear ratio can be varied over a much wider range.

The steering gear consists of two horizontal rods and rotary levers. telescopic racks front suspension. The rods are connected to the swing arms using ball joints. The swing arms are welded to the front suspension struts. The rods transmit the force to the pivot arms of the telescopic wheel suspension struts and respectively turn them to the right or left.

The benefits of rack and pinion steering include:

Light weight

compactness

low price

Minimum number of rods and hinges

Ease of connection of the steering gear with the steered wheels

Direct transmission of force

High rigidity and efficiency

Easy to equip with hydraulic booster

Flaws:

Due to the simplicity of the design, any push from the wheels is transmitted to the steering wheel.

Difficulties in the manufacture of a mechanism with a high gear ratio, therefore, such a mechanism is not suitable for heavy machines.

Selection and justification of the chosen design

In terms of its technological, price, and design qualities, the rack-and-pinion steering mechanism is most suitable for the front-wheel drive layout and McPherson suspension, providing greater ease and steering precision.

When designing the VAZ-2123 car, they tried to take as many nodes as possible from the VAZ-2121 model, so a “worm-roller” type mechanism was installed on the car. However Chevrolet Niva is not powerful SUV so that it would be advisable to put this mechanism on it. It is more expensive, technologically complex, heavier. The possibilities that the worm gear gives the car are not fully used. When using reykm, the concentration of stress from the steering mechanism on the side member is excluded, there is no need to strengthen it at the place where the mechanism is attached.

For all these reasons, I consider it necessary to replace the “worm-roller” mechanism with a cheaper, lighter, more technologically advanced one. rack and pinion mechanism, which in necessary measure provides ease and precision of a steering.

Due to the fact that the type of mechanism will be replaced, it is necessary to make a number of changes to the design of other components and assemblies:

Since it is not possible to place the rack and pinion behind the axle of the front wheels, we put it in front of the axle;

In order to free up space between the engine tray and the differential for the rack, we shift the cross-axle differential by the same distance (20.5 mm) back, which does not change the balance of the entire assembly;

Since the rail is located in front of the axle, then stopping support wheels must be placed at the rear.

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.

Most widespread in cars Today received rack and pinion steering mechanisms.

Rack and pinion steering mechanism without hydraulic booster:
1 - case;
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 steered wheels.
Causes wide application on passenger cars, just such a mechanism is: 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; tendency to vibroactive steering, increased loading of parts, the difficulty of installing such a steering mechanism on vehicles with dependent suspension steered wheels. This limited the scope of this type of steering mechanisms only to cars (with a vertical load on steered axle up to 24 kN) vehicles 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 trucks and buses, cars high cross are equipped, as a rule, with steering mechanisms of the "globoidal worm-roller" type. 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 (variable diameter worm) 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 steering angles 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 cars high class and a large dead weight with independent suspension of the steered wheels, but in this case the design of the steering gear becomes more complicated - an 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 a screw-nut pair, forces are transmitted in it by means of balls circulating in a helical groove. This steering mechanism 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 hydraulic booster steering.
Earlier on trucks it was possible to meet other types of steering mechanisms, for example, “worm-side sector”, “screw-crank”, “screw-nut-rod-lever”. On modern cars such mechanisms are practically not used due to their complexity, the need for adjustment and low efficiency.

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, a gear) installed in a 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 by as 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 through a certain angle, connected through the drive parts to the output shaft of the gear, the driver needs to turn the steering wheel to a larger angle than with a small gear ratio. When the vehicle is moving with 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 wheel angles, to obtain significant angles of rotation of the steered wheels, 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 maximum angle(35 ... 45 °) 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 gearbox 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 the 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, ensures good engagement of the roller ridges with a limited length with worm cutting. Due to the fact that the load action 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 a position corresponding to the rectilinear movement of the machine, free play the steering wheel is practically absent, and as the steering angle increases, it increases.

The tightening of the steering shaft bearings is adjusted by changing the number of gaskets installed under the crankcase cover, with its plane resting against the end of the extreme conical roller bearing. The engagement of the worm with the roller is adjusted by shifting the steering arm shaft 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 cars heavy duty steering mechanisms 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 cover of the steering gear housing.

The design of the steering mechanism of the "screw-ball nut-rail-sector" type is shown in the figure. Steering wheel shaft through driveline connected to the screw 4, which interacts with the ball nut 5, which is fixed by the locking screw 15 in the piston rail 3. The thread of the screw and the 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 on vehicles intended for movement on rails, there are steering devices. 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 dimensions, and on others constructive solutions specific model There are currently 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 mainly used on buses and small trucks, on off-road cars and cars 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 enough 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 an overpass or going down into 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.

Each node and mechanism of the car is important in its own way. Perhaps there is no such system, without which the car could function normally. One of these systems is the steering mechanism. This is probably one of the most important parts of the car. Let's look at how this node is arranged, its purpose, structural elements. And also learn how to regulate and repair this system.

The principle of operation of rack and pinion tie rod

Rack and pinion steering

The rack and pinion steering mechanism is the most common type of mechanism installed on cars. The main elements of the steering mechanism are the gear and the steering rack. The gear is mounted on the steering wheel shaft and is in constant engagement with the steering (gear) rack.
Scheme rack and pinion steering

1 - plain bearing; 2 - cuffs high pressure; 3 - body of spools; 4 - pump; 5 - compensation tank; 6 – steering draft; 7 - steering shaft; 8 - rail; 9 - compression seal; 10 - protective cover.
The operation of the rack and pinion steering mechanism is as follows. When the steering wheel is turned, the rack moves to the left or right. During the movement of the rack, the steering rods attached to it move and turn the steered wheels.

The rack and pinion steering mechanism is distinguished by its simple design and, as a result, high efficiency, and also has high rigidity. But this type of steering mechanism is sensitive to shock loads from road irregularities, prone to vibrations. Due to its design features, the rack and pinion steering gear is used on front wheel drive vehicles

Worm gear

Scheme worm gear

This steering mechanism is one of the "obsolete" devices. They are equipped with almost all models of domestic "classics". The mechanism is used on cars with cross-country ability with dependent suspension of steered wheels, as well as in light trucks and buses.

Structurally, the device consists of the following elements:

• steering shaft
• worm-roller transmission
• crankcase
• steering arm

A pair of "worm-roller" is in constant engagement. The globoidal worm is the lower part of the steering shaft, and the roller is mounted on the bipod shaft. When the steering wheel is rotated, the roller moves along the teeth of the worm, due to which the steering arm shaft also rotates. The result of this interaction is the transfer translational movements for drive and wheels.

The worm gear steering has the following advantages:

• the ability to turn the wheels at a greater angle
• shock absorption from road bumps
• transmission of great effort
• providing better machine maneuverability

The manufacture of the structure is quite complicated and expensive - this is its main disadvantage. Steering with such a mechanism consists of many connections, the periodic adjustment of which is simply necessary. Otherwise, you will have to replace damaged items.

Steering column

Performs the transfer of rotational force that the driver creates to change direction. It consists of a steering wheel located in the passenger compartment (the driver acts on it by rotating it). It is rigidly planted on the column shaft. In the device of this part of the steering, a shaft is often used, divided into several parts interconnected cardan joints.

This design is not just made. Firstly, it allows you to change the angle of the steering wheel relative to the mechanism, to shift it in a certain direction, which is often necessary when arranging constituent parts auto. In addition, this design allows you to increase the comfort of the cabin - the driver can change the position of the steering wheel in terms of reach and tilt, providing the most comfortable position.

Secondly, the composite steering column tends to “break” in the event of an accident, reducing the likelihood of injury to the driver. The bottom line is this - in a frontal impact, the engine can move back and push the steering mechanism. If the column shaft were solid, changing the position of the mechanism would lead to the output of the shaft with the steering wheel into the passenger compartment. In the case of a composite column, the movement of the mechanism will be accompanied by only a change in the angle of one component of the shaft relative to the second, and the column itself remains motionless.

Screw steering gear

The screw steering mechanism integrates the following structural elements: screw on steering wheel shaft; a nut that moves along the screw; gear rack, cut into a nut; toothed sector connected to the rail; steering arm located on the sector shaft.

A feature of the screw steering mechanism is the connection of the screw and nut with the help of balls, which achieves less friction and wear of the pair.

In principle, the operation of the screw steering mechanism is similar to the operation of the worm gear. Turning the steering wheel is accompanied by the rotation of the screw, which moves the nut put on it. In this case, the circulation of the balls occurs. Nut by means of a gear rack moves the gear sector and with it the steering arm.

Screw steering vs. worm gear has greater efficiency and realizes greater efforts. This type steering gear is installed on individual cars executive class, heavy trucks and buses.

Conclusion

In general, the mechanism is a fairly reliable unit that does not require any maintenance. But at the same time, the operation of the steering of a car implies timely diagnostics to identify faults.

The design of this node consists of many elements with movable joints. And where there are such connections, over time, due to the wear of the contacting elements, backlashes appear in them, which can significantly affect the handling of the car.

The complexity of steering diagnostics depends on its design. So in nodes with a gear-rack mechanism, there are not so many connections that need to be checked: tips, gear engagement with a rack, steering column universal joints.

But with a worm gear, due to the complex design of the drive, there are much more diagnostic points.

Concerning repair work in the event of a malfunction of the assembly, then the tips are simply replaced in case of severe wear. In the steering mechanism, at the initial stage, the backlash can be removed by adjusting the gearing, and if this does not help, by reassembling the assembly using repair kits. The cardan shafts of the column, as well as the tips, are simply replaced.