Elastic suspension elements. Car suspension - everything car owners need to know about it

Vehicle suspensions are classified according to the types of guides, elastic elements and damping devices (shock absorbers).

By type of guides

According to the type of guide devices, suspensions are distinguished:

• dependent
• independent
• balancing

In dependent suspension with a cross-link, the wheels of two sides of one bridge are connected by a rigid beam (see Fig. a). In this case, the vertical movement of one wheel relative to the carrier system causes a change in the inclination of the rolling plane of the other wheel.

In independent suspension each wheel (skating rink) moves relative to the carrier system independently of the other. Figure b shows an independent single wishbone suspension with a transverse arm. Such a guide device ensures the movement of the wheel in the transverse plane with a change in the angle of its inclination and the track of the vehicle. Depending on the design, independent suspensions can be single-lever with a longitudinal arrangement of the lever (figure a) and double-lever with a transverse arrangement of the levers (figure b).

Single-lever suspensions with a trailing arm completely exclude changes in the angle of inclination of the wheel and the track of the vehicle, while double-lever suspensions ensure their minimum changes when right choice the ratio of the lengths of the levers and the angles of their installation.

In balance beams(in dependent suspensions with a longitudinal connection) the wheels (rollers) of one side of the vehicle are connected to each other by swinging balancers, the role of which can be played by leaf springs or rigid beams (Fig. a, b). In such suspensions, even in the absence of an elastic element, the vertical movement of one of the wheels causes half the movement of the swing axis of the balancer mounted on the carrier system of the vehicle, which improves the smoothness of the machine. Balancing suspensions, due to the rocking of the balancer, provide a redistribution of the load acting on the wheels, which significantly reduces the impact of road irregularities on the vehicle as a whole.

Rice. Schemes of independent suspensions:
a - single-lever with a longitudinal arrangement of the lever; b - double-sided with transverse levers

By type of elastic elements

According to the type of elastic elements, suspensions with elastic elements are distinguished:

• metal
• non-metallic

As metal elastic elements leaf springs, coil springs (cylindrical or conical) and torsion bars are used. Non-metallic elastic elements include pneumatic and rubber elastic elements.

The leaf spring consists of several steel sheets (most often 6 - 14), having different lengths and curvature and, as a rule, a rectangular section. The length of the sheets is selected from the condition that the shape of the spring approaches the shape of the beam equal resistance bending, which under this type of load is the least rigid.

Rice. Schemes of balancing suspensions:
a - with an elastic balancer in the form of a leaf spring; b - with a rigid balancer; AB, DC - reactive and pushing rods, respectively

In the manufacture of leaf springs, the sheets are given different curvature, therefore, during assembly, they are subjected to preliminary deformations, the sign of which is opposite to the sign of working deformations. This provides some unloading of the leaf springs. The sheets are assembled into a package using clamps, some springs are pulled together with a central bolt and then installed between the axle and the carrier system of the machine. Leaf springs are usually semi-elliptical in shape.

If the leaf spring is used in a dependent cross-link suspension, its middle part is attached to the bridge beam with the help of ladders, and the ends are hinged (using special brackets) to the carrier system of the machine. The front end of the spring is fixedly attached to the frame bracket with a pin, and the rear end has a sliding connection in the bracket inserts. In some cases, the ends of the springs are connected to the carrier system using rubber pads fixed in the brackets, thus providing a fixed connection of the front end and a sliding connection of the rear end of the spring. In this design of the suspension, the spring simultaneously acts as an elastic element and a guide device, i.e. through it, forces acting in the horizontal plane and moments from them are transmitted from the propulsion system to the carrier system.

If the spring is used in a balancing suspension, its middle is attached with stepladders to a hub mounted on a frame support, which is the swing axis of the balance beam. The ends of the springs rest on brackets - bridge supports. The design of the brackets ensures the sliding of the ends of the spring in the longitudinal direction and a rigid connection with the bridge in the transverse direction.

Communication in the longitudinal direction, as well as the transfer of reactive moments, are carried out using pushing and reactive rods connecting the beams of the bridges with the carrier system. In order to ensure free movement of the beams of the bridges in the vertical direction and to allow some distortions, the ends of the rods are connected to the bridges and the frame by ball joints. In order for the forces acting from reactive moments along the reaction rods not to reach large values, the attachment points of the ends of these rods to the axle beams are moved as high as possible from the axis of rotation of the wheels by installing special brackets on the axle beams.

During the operation of leaf springs, a relative movement of the sheets occurs in the longitudinal direction and interleaf friction is created, which, on the one hand, contributes to the damping of vibrations, and on the other hand, adversely affects the smoothness of the vehicle due to suspension blocking at high friction forces. To reduce friction, the spring leaves are lubricated with graphite grease during assembly or non-metallic anti-friction gaskets are used between the sheets. Reducing the friction force is also achieved by reducing the number of sheets in the spring and using a spring consisting of a single sheet with a variable cross section along its length. The use of single-leaf or small-leaf springs reduces the consumption of metal, which, in turn, reduces the weight of the suspension.

Spiral springs as the main elastic elements are usually installed on cars in independent lever pendants. In heavy-duty vehicles, springs are used as auxiliary elastic elements, for example, as stops for torsion bar suspensions tracked vehicles. Most often, cylindrical and conical springs of round or rectangular sections are used.

Torsion elastic elements, or simply torsion bars, are rods of various cross sections made of high-quality steel, working in torsion. They are used in independent suspensions and, unlike leaf springs, require guides. At the ends of the torsion bars there are usually heads with slots. One end of the torsion bar is fixed in a special bracket on the carrier system of the machine, and the other end is connected through the guide lever to the wheel (roller). When moving the wheel in the vertical direction, the torsion bar twists at an angle of up to 30 ... 45 °, thereby ensuring the elasticity of the suspension.

According to the location on the vehicle, torsion bars are distinguished:

• longitudinal
• transverse

In pneumatic suspensions, as an elastic element, compressed air or nitrogen enclosed in a rigid or elastic shell. When the wheel moves relative to the carrier system, the volume of gas changes. The nature of this change determines the elastic characteristic of the suspension.

Pneumatic elastic elements, in which the gas is enclosed in an elastic shell, are rubber-cord shells sealed at the ends and filled with air under pressure. Three types of these elements are used in the vehicle: air springs, sleeve and diaphragm elastic elements.

Pneumocylinders are made one-, two- and three-section. A two-section air spring (Fig. a) consists of a shell 1 with a thickness of 3 ... 5 mm, reinforced with steel wire rings 2 for fastening to support flanges 4 using rings 3. In the middle part, the shell is pulled together by ring 5.

Rice. Pneumatic elastic elements with gas enclosed in an elastic shell:
a - two-section pneumocylinder; b - sleeve type element; V - circuit diagram body position control

Sealing of the shell of the sleeve elastic element (Fig. b) is carried out using clamping flanges 6 or under air pressure.

The diaphragm elastic element differs from the sleeve element by the presence of a rigid side shell. The lower end part of its shell is an elastic diaphragm. The cord fabric of the shell is made of polyamide threads (nylon, capron).

Pneumatic elastic elements with gas enclosed in a rigid shell are divided into three types: with one pressure stage (Fig. a), when the compressed gas is located above piston 1 in one volume (chamber A); with counterpressure (Fig. b), when the gas is both in the above-piston space (chamber A) and under piston 1 (chamber B), and the gas pressure is greater in chamber A; with two pressure stages (fig. c), when two chambers A and B are located above the piston 7. In the latter case, the charging pressure of the gas chambers is different. In chamber A, the gas is compressed during the entire suspension stroke, and in chamber B, the gas begins to compress when a pressure greater than the charging pressure of this chamber is reached.

The transfer of forces from the piston to the gas is carried out through the liquid with which the cylinder is filled. In some cases, the liquid is in direct contact with the gas (chamber B in Fig. b), but most often it is separated from the gas by a flexible separator (diaphragm) 3 or a floating piston 13 shown in the figure.

With direct contact of the liquid with the gas during the operation of the suspension, foaming occurs, which adversely affects the characteristics of the elastic element.

Rice. Schemes of pneumatic elastic elements with gas, enclosed in a rigid shell, with one pressure stage (a), with counterpressure (b) and with two pressure stages (c)

The use of liquid in such elastic elements provides damping of vehicle mass oscillations when it flows through calibrated holes and valves 2. Thus, an assembly is obtained in which both the elastic element and the shock absorber are located.

The figure shows the device of a pneumatic elastic element with one pressure stage, which does not have damping properties, but has additional rubber elastic elements 7. Filling with gas and liquid is carried out, respectively, through valves 19 and 27. The elastic elements work at the beginning and end of the suspension stroke. The gas is separated from the liquid by a floating piston 13. The elastic element through the earring 1 and the bearing 2 is attached at one end to the suspension guide, and at the other end to the carrier system of the machine.

The use of pneumatic elastic elements allows you to adjust the position of the body and ground clearance, as well as change the elastic characteristics of the suspension.

A schematic diagram of the regulation of the height of the vehicle body by the mass of gas in the elastic element is shown in figure c. As the load increases, the car body lowers and the distance between it and the axle decreases. The lever drive, acting on the regulator 8, ensures the communication of the elastic element 7 with the receiver. Air under pressure enters the elastic element until the body rises to its previous level. When the load decreases, the distance between the body and the bridge will also remain unchanged, since with the help of the regulator 8, air is released from the elastic element 7 into the atmosphere. The use of a hydraulic retarder built into the regulator eliminates the operation of the regulator when the vehicle oscillates on the suspension.

The height of the body can be adjusted by changing the volume of liquid between the gas and the piston. In these systems, to raise the body of the vehicle, the liquid is injected into the elastic element, and to lower it is removed.

On a number of vehicles there is a system for regulating the position of the body, with which you can not only change the ground clearance of the entire car, but also give the body a trim for the bow or stern or roll on board by selecting the parameters of the corresponding suspensions.

Rubber elastic elements are used in vehicle suspensions as suspension travel stops and in shock absorber attachment points, reducing the dynamic loading of suspension parts and the carrier system.

As damping devices in the TS, they are used, in which the mechanical energy of the TS vibrations is converted into thermal energy by liquid friction when a viscous liquid passes through holes of small cross section. The liquid heats up and the heat is dissipated in the surrounding space.

Structurally hydraulic shock absorbers perform telescopic and lever. Telescopic ones operate at liquid pressure up to 8 MPa, and lever ones - up to 30 MPa. Telescopic shock absorbers are divided into two-tube and one-tube. Lever can be piston and bladed.

Rice. Pneumatic elastic element with additional elastic elements:
1 - earring; 2 - articulated bearing; 3, 15, 17 - seals; 4, 8 - glasses; 5 - cover; 6, 11, 14 - washers; 7 - additional elastic elements; 9 - piston; 10 - cylinder; 12 - cuff; 13 - floating piston; 16 - cover; 18 - bushing; 19, 21 - charging valves; 20 - bypass valve

Mineral oils are used as workers.

During the operation of the shock absorber, a compression stroke and a rebound stroke are distinguished. During the compression stroke, the wheel (skating rink; approaches the carrier system of the vehicle, and during the rebound, on the contrary, moves away from it.

The device and principle of operation of a double-acting hydraulic telescopic double-acting shock absorber

Consider the device and principle of operation of a double-acting hydraulic telescopic double-acting shock absorber. The shock absorber with eye 6 is attached to the carrier system of the machine, and with eye 1 - to the guide device. The shock absorber consists of a rod 5, at the lower end of which a piston 8 is fixed with valves and channels calibrated in cross section. The piston is located inside the working cylinder 12, which is enclosed in the outer tube 13 and fastened to it. Between the outer cavity of the cylinder and the inner surface of the pipe there is a gap forming a compensation chamber 3 of the shock absorber. In the upper part of the cylinder there is a seal through which the rod passes. The lower part of the cylinder is connected to the compensation chamber by valves and calibrated channels.

In the piston there are calibrated holes 4 of the rebound stroke, a bypass valve 7 of compression and an unloading valve 9 of rebound.

In the lower part of the cylinder there is a release valve 10, a calibrated compression channel 2 and a compression relief valve 11. During the compression stroke, when the rod moves into the cylinder, the pressure under the piston rises, and the liquid flows through the hole 4 and the valve 7 into the space above the piston. Due to the fact that the volumes of the cavities under the piston and above it are not the same (part of the volume above the piston is occupied by the rod), excess liquid flows through channel 2 into the compensation chamber, compressing the air present there. At high speed moving the piston in the cylinder, the pressure under it rises so much that it compresses the spring of the unloading valve 11, which opens, and the pressure increase decreases, which limits the resistance force of the shock absorber on the compression stroke. During the rebound, when the piston moves out of the cylinder, the pressure above the piston increases and the liquid flows through the calibrated holes 4 into the space above the piston. The liquid deficit under the piston will be covered by its flow from the compensation chamber to the cylinder through valves 10 and channel 2. At a high piston speed during the rebound stroke, the pressure above the piston increases, which causes the opening of the rebound relief valve 9 in the piston and thereby limits the resistance force of the shock absorber to during the retreat.

Rice. Scheme of a hydraulic telescopic double-acting double-acting shock absorber

The normal condition for the operation of the shock absorber is the absence of air inclusions in the fluid. In the considered shock absorber, air inclusion can occur due to agitation of the liquid in the compensation chamber, where the liquid is in contact with air.

This drawback does not have a double-acting hydraulic telescopic single-tube shock absorber, in which two valves (rebound 3 and compression 2) are located in the piston, and the role of the compensation chamber is performed by cavity A, separated from the under-piston space by a floating piston 7. In cavity A there is compressed gas, the volume which decreases during compression and increases during rebound.

In lever shock absorbers, the lever is connected at one end to the suspension guide, and at the other - to the piston or blade. When the latter move inside the shock absorber body, fluid from one cavity flows into another through valves and holes, the sections of which determine the rebound and compression characteristics.

Along with the considered shock absorbers, there are those in the design of which it is possible to control the parameters that determine their damping properties by changing the total area of ​​the holes through which flows working fluid. Regulation is carried out by changing the mass of the machine or the intensity of vibrations. With an increase in the values ​​of these parameters, the resistance of the shock absorbers increases.

Rice. Scheme of a hydraulic telescopic double-acting single-tube shock absorber

avoiding technical terms, we can say that the suspension is necessary in order to reduce the effect of road bumps on the car body. For this, elastic elements are provided in the design of the suspension. These include springs, springs, and rubber elements (chippers, buffers, silent blocks). There are also pneumatic and hydropneumatic elastic elements.

Metal elastic elements

Springs

Springs, as an elastic suspension element, are currently used in the vast majority of cars. Made from a metal rod of round section, they have constant characteristic rigidity and perfectly cope with the task assigned to them. The coils converge evenly as the load increases, and return to their original position when it is removed.

If there is a need for variable stiffness, then the springs are made from a bar of various diameters (in certain areas), or in the form of a barrel (some coils are narrower). In this case, when the spring receives a load, the coils of smaller diameter (thickness) will approach first.

The advantage of the spring, as an elastic element, is the ease of manufacture, which means the final cost of the product, and its low weight. But since it cannot transmit forces in the transverse plane, it requires the vehicle suspension to have complex guiding devices. Which in turn affects both the price and the weight of the entire assembly.

springs

Another elastic element of the car's suspension are leaf springs. Due to the large weight, compared to the same springs, the springs are mainly used in the suspension of trucks. The spring consists of metal sheets (in very rare cases, reinforced plastic), of various lengths and shapes, interconnected by a bolt in the center, and with clamps closer to the edges. Being equal in width, each plate, depending on the length, has a different degree of convexity. This provides the spring required characteristics. The longest (root) plate is attached to the car body or frame.

There are several basic ways to attach the spring to the body:

• with twisted ears;
• sliding support and false ears;
• rubber pads.

Each of the mounting methods has its own characteristics and characteristics. General requirement to any of the listed methods of fastening - the ends of the plates must be able to move and rotate. During the operation of the spring suspension, the sheets rub against each other. This requires the use of additional lubrication, or the presence of anti-friction gaskets.

Rubber elastic elements of the car suspension

These elements play an auxiliary role in the operation of the suspension, however, they can also be attributed to elastic elements. They primarily help to avoid hitting the metal parts of the suspension against each other, thereby minimizing the noise level. They also increase the rigidity of the main elements and limit the degree of their deformation.

Rubber elements do an excellent job of both compression and rebound. So, for example, polyurethane bumpers installed in the shock absorber strut work great for rebound.
The different shape, as in the case of a spring, determines the performance of the rubber element. The shape of the cone allows for smooth performance, first the thin, upper part is compressed, the closer to the thick part, the more elastic the rubber becomes.

Today, step-shaped fenders are often found, having alternating thin and thick parts. This allows you to significantly increase its working stroke.

Pneumatics and hydropneumatics

Air suspension is used both in cars and in freight and passenger transport. Pneumatic elastic element, allows you to change the stiffness of the suspension depending on traffic situation, car load. IN modern cars, air suspension controls the electronics, which is able to independently monitor its work, and change its rigidity depending on the situation.

Pneumatic elements

Pneumatic elements (air cylinders) change their severity due to the air pressure created inside the compressor. The cylinders are made of oil-resistant and air-tight rubber, contain cord and metal threads, which makes them more rigid and reliable. Hence the name - rubber-cord elastic elements. The wall thickness of such a cylinder is usually from 3 to 5 mm.

Hydropneumatic elements

This elastic element provides greatest comfort for the driver and passengers of the car, as it does an excellent job of damping suspension vibrations. The hydropneumatic elastic element is a chamber with two cavities. One of them is filled with gas, and the other with liquid, which, as you know, have different degrees of compression. Through a complex system of membranes and valves, liquid and gas interact to varying degrees (depending on the situation), which provides the necessary comfort and elasticity of the car's suspension.

The ubiquity of this pendant is limited, perhaps, only by its high cost.

Progress does not stand still, and every year engineers are getting closer and closer to creating a suspension that is ideal in all respects and will meet all necessary requirements. Perhaps not far off is the day when being in the car (when driving on the most terrible off-road), in terms of comfort, can be compared with sitting on a soft sofa.

car suspension- this is a device that provides elastic grip of the wheels of the car with the carrier system, and also regulates the position of the body during movement and reduces the load on the wheels. Modern automotive industry offers various types of car suspensions: pneumatic, spring, spring, torsion, etc.

Suspension guides. A set of devices that connect the wheels and the car body forms the suspension. The main purpose of the suspension is to convert the impact on the car from the road into acceptable vibrations of the body and wheels. These interactions should be such that the car not only picks up speed quickly (accelerates), but can also slow down even faster (up to a complete stop). In addition, the machine must be easy to control and stable while driving. To perform these tasks, the suspension is used, the design of which determines the main operational properties of cars, including traffic safety.

When the car is moving, the wheels move relative to the body and the road in vertical and horizontal directions, as well as at an angle (rotation around the axis, inclination relative to the body and the road, rotation around the axis of rotation - the pivot axis). To meet the requirements related to operational properties vehicle, it is necessary to significantly limit the movement of the wheels. With the transverse (lateral) movement of the wheels in horizontal directions, the track changes, and with the longitudinal - the base of the car. The presence of such movements leads to an increase in resistance to movement, tire wear, deterioration of stability and controllability. The vertical movement of the wheels relative to the body of passenger cars can exceed 20 cm. The angles of rotation of the wheels are 30 ... 45 °.

In order for the car to successfully accelerate and brake, to “keep” the road well, it is necessary to have reliable grip wheels with its surface. Does suspension affect grip? Undoubtedly. Grip depends not only on the characteristics of the tire tread and the quality of the road, but also on the load that is transferred to the wheels. The change in the vertical load on the wheels is determined by the deflection of the springs and the efforts from the shock absorbers. With a decrease in the vertical load, the grip of the wheels with the road surface decreases.

The suspension of a car contains the following main devices: guiding devices (levers, struts, rods, extensions), elastic elements (leaf springs, springs, air springs, etc.), damping devices (hydraulic shock absorbers) and, finally, regulation and control devices (height and roll regulators, computers, etc.).

Suspension guides affect the nature of the movement of the body and wheels of the car during vibrations. Whether, for example, the lifting of the wheel will be accompanied by its inclination, lateral or longitudinal movement depends on the scheme according to which the guide devices are made. Guide devices serve to transfer traction and braking forces, as well as lateral forces that occur when turning, moving along a slope from the wheels to the body.

According to the type of guide devices, all suspensions are divided into dependent and independent. With dependent suspension, right and left wheel connected by a rigid beam - a bridge. Therefore, when one of the wheels hits an unevenness, both wheels tilt in the transverse plane at the same angle. In an independent suspension, the movements of one wheel are not rigidly connected with the movements of the other. Tilts and movements of the right and left wheels are significantly different.

Elastic devices (elastic elements) serve to reduce the loads acting between the wheel and the body. When hitting road bumps elastic elements are deformed. After the passage of irregularities, the elastic elements cause oscillations of the body and wheels. The main characteristic of elastic elements is stiffness, i.e. the ratio of vertical load to deflection (or spring settlement). The elastic elements of the wheel suspension are distinguished not only by design, but also depending on what material they are made of. If the elastic properties of the metal (resistance to bending or torsion) are used, then metal elastic elements take place. Given the elastic properties of rubber and plastics, rubber and plastic springs are widely used. Recently, air springs have been widely used, where the elastic properties of air or gases are used.

Damping suspension devices (hydraulic shock absorbers) are designed to dampen vibrations of the body and wheels. During the operation of the suspension, the energy of the vehicle's vibrations is redistributed between the body and the wheels. Shock absorbers absorb this energy, turning it into heat. The more energy the shock absorber absorbs, the faster the vibrations of the body and wheels will dampen, the less the body will sway. Riding on soft springs without shock absorbers is almost impossible.

It is possible to significantly reduce the inclination and lateral movement of the wheels using a double wishbone suspension scheme. With the help of a short upper and long lower levers, it is possible to reduce the angular and lateral movements of the wheels. The effect of lean (angle) can be reduced by using camber (tilt) in the vertical plane and derailment (difference between the side surfaces of the tire in front and behind) of the wheels. The lateral movement of the wheels can be compensated by the compliance of the tires.

The double-lever suspension has a number of advantages in the location of the main elements: the shock absorber is fixed inside the spring; the spring and shock absorber rest on the lower arm, which reduces the overall height; wishbones reliably transfer pushing and braking forces from the wheel to the body. Double-lever guides are widely used in front independent suspensions of cars.

Even less angular and transverse movements of guide devices in telescopic spring struts front wheel drive vehicles, where instead of two levers in the transverse plane, one lower transverse lever with braces is installed. Such a suspension is called a swinging candle, or, as it is called by the name of the inventor, the MacPherson suspension. With only the lower arm and top support suspension has minor changes wheel tread and inclination, which reduces tire wear and improves vehicle stability. The disadvantages of the scheme include the high location of the upper support, which must be placed in the front of the body, as well as the large loads that occur in the places where the upper support is attached to the body.

The use of trailing arms in the guide devices allows you to avoid changing the inclination of the wheels when vertical movements. However, long trailing arms experience significant loads under the action of lateral forces (during a turn, exit to the side of the road, impacts from road irregularities). With this design of the guide device in independent suspensions, it is difficult to drive to the wheel using cardan gears; to reduce the side roll of the body, it is necessary to install an additional elastic element - a stabilizer roll stability. Guides with trailing arms used on the rear suspension of front-wheel drive vehicles.

Elastic suspension elements. Consider the design of elastic elements (springs) of the wheel suspension. The oldest elastic element is the leaf spring. A conventional leaf spring is a pack (trapezium-shaped) of flat steel strips tightened together. The longest root sheet has lugs at the ends, with which the spring is attached to the body. Most often, longitudinal leaf springs are installed on the rear suspensions of cars. The more sheets in the package, the more load the spring can take. Increasing the length of the spring makes it possible to increase the deflection and, consequently, the wheel travel, i.e. make the suspension long-stroke and soft. The main feature of leaf springs is that they can play the role of not only an elastic element, but also a guiding device. Through the leaf spring, all the loads arising from the rolling of the wheels are transmitted. Springs transmit pushing forces during acceleration and braking. When driving on a slope, when turning the car, as well as under the influence of other lateral forces, the springs are subjected to torsion. The greatest loads fall on the root sheets of the spring. The durability of leaf springs at heavy loads is significantly reduced. Another feature of leaf springs is the presence of friction between the sheets. Friction forces prevent the deflection of the spring and impair its elastic properties. There is a blocking of the elastic element, and the load from the wheels is transferred directly to the body. As a result, the smoothness of the ride significantly deteriorates. These shortcomings of leaf springs are noticeably manifested when the car is moving over uneven roads that have a small height. Then, with an increase in speed, intense vibrations and noise occur in the passenger compartment. To get rid of the harmful effects of friction, non-metallic gaskets are installed between the sheets.

In addition to these disadvantages, multi-leaf springs have others. In the suspension with such springs, additional elastic elements are installed - stops (buffers) to limit breakdown and increase rigidity; springs have a large mass, short service life, they are difficult to arrange in systems independent suspension passenger car.

Improving the design of leaf springs led to the creation of the so-called small leaf springs. The sheets of such a spring are strips of variable cross-section along the length. The manufacture of leaf springs is associated with a number of technological difficulties, however, leaf springs of the same load capacity as conventional multi-leaf springs have a significantly lower weight (by 20 ... 30%). They have significantly less intersheet friction. IN last years In order to reduce the weight, attempts have been made to manufacture leaf springs from composite materials.

Metal elastic elements made in the form of twisted springs and steel rods (torsion bars) turned out to be more perfect in comparison with leaf springs. With the same load capacity as leaf springs, the springs and torsion bars have a significantly lower weight and are more durable.

With the advent of front independent suspension, springs have become the most widespread. The simplest coiled springs with a constant wire thickness and a constant winding pitch. Such springs provide the suspension with the necessary wheel travel and low stiffness.

However, soft springs do not allow the suspension to provide protection from shocks and shocks at the end of the wheel travel up (compression) and down (rebound). As a rule, it is necessary to stiffen the suspension with a spring at the end of the compression and rebound stroke, which is achieved by installing additional elastic elements.

As additional elastic elements, rubber or plastic buffers are most often used.

To improve the characteristics of the spring, shaped springs are used with different winding pitch and wire thickness (conical, barrel-shaped, etc.). However, the manufacture of such springs in the conditions of mass production of passenger cars is much more difficult.

The road along which the driver chooses the route of movement is not always flat and smooth. Very often, there may be such a phenomenon as surface irregularities - cracks in the asphalt and even bumps and potholes. Do not forget about the "speed bumps". This negative would have a negative effect on the comfort of movement, if there were no depreciation system - the suspension of the car.

Purpose and device

During the movement, the roughness of the road in the form of vibrations is transmitted to the body. The vehicle's suspension is designed to dampen or mitigate such vibrations. Its application functions include providing communication and connection between the body and the wheels. It is the suspension parts that give the wheels the ability to move independently of the body, providing a change in the direction of the car. Along with the wheels, it is an indispensable element of the chassis of the car.

The suspension of a car is a technically complex unit having the following structure:

1. elastic elements - metal (springs, springs, torsion bars) and non-metal (pneumatic, hydropneumatic, rubber) parts, which, due to their elastic characteristics, take the load from road irregularities and distribute it to the car body;
2. damping devices (shock absorbers) - units having a hydraulic, pneumatic or hydropneumatic structure and designed to level body vibrations received from an elastic element;
3. guide elements - various details in the form of levers (transverse, longitudinal), providing connection of the suspension with the body and determining the movement of the wheels and the body relative to each other;
4. anti-roll bar - an elastic metal bar that connects the suspension to the body and prevents the car from increasing roll during movement;
5. wheel supports - special steering knuckles(on the front axle), perceiving the loads emanating from the wheels, and distributing them to the entire suspension;
6. fastening elements of parts, components and assemblies of the suspension - these are means of connecting the suspension elements with the body and among themselves: rigid bolted connections; composite silent blocks; ball joints (or ball bearings).

Principle of operation

The scheme of operation of the car suspension is based on the conversion of the impact energy arising from the impact of a wheel on an uneven road surface into the movement of elastic elements (for example, springs). In turn, the rigidity of the movement of the elastic elements is controlled, accompanied and softened by the action of damping devices (for example, shock absorbers). As a result, thanks to the suspension, the impact force that is transmitted to the car body is reduced. This ensures smooth running. The best way to see the operation of the system is to use a video that clearly demonstrates all the elements of the car's suspension and their interaction.

Cars have a variety of suspension stiffness. The stiffer the suspension, the more informative and efficient driving is. However, comfort suffers greatly. And vice versa, soft suspension designed in such a way that provides ease of use and sacrifices handling (which should not be allowed). That is why car manufacturers strive to find their most best option– a combination of safety and comfort.

Variety of suspension options

The vehicle suspension device is an independent design solution of the manufacturer. There are several typologies of car suspension: they are distinguished by the criterion underlying the gradation.

Depending on the design of the guide elements, the most common types of suspension are distinguished: independent, dependent and semi-independent.

A dependent option cannot exist without one detail - a rigid beam that is part of the vehicle's axle. In this case, the wheels in the transverse plane move in parallel. The simplicity and efficiency of the design ensures its high reliability, preventing wheel collapse. That is why the dependent suspension is actively used in trucks and on rear axle cars.

The scheme of independent suspension of the car assumes the autonomous existence of the wheels from each other. This allows you to increase the damping characteristics of the suspension and provide greater smoothness. This option actively used to organize both the front and rear suspension on cars.

The semi-independent version consists of a rigid beam fixed to the body with torsion bars. This scheme provides the relative independence of the suspension from the body. Its typical representative is front wheel drive models VAZ.

The second typology of suspensions is based on the design of the extinguishing device. Specialists distinguish hydraulic (oil), pneumatic (gas), hydropneumatic (gas-oil) devices.

The so-called active suspension stands out in a certain way. Its scheme includes variable possibilities - changing the suspension parameters using a specialized electronic system control depending on the driving conditions.

The most common changeable parameters are:

• the degree of damping of the extinguishing device (shock absorber device);
• the degree of rigidity of the elastic element (for example, springs);
• the degree of rigidity of the anti-roll bar;
• length of guide elements (levers).

Active suspension is an electronic-mechanical system that significantly increases the cost of the car.

The main types of independent suspension

In modern passenger cars, an independent suspension option is very often used as a shock-absorbing system. This is due to the good controllability of the car (due to its small mass) and the absence of the need for total control over the trajectory of its movement (as, for example, in the variant with freight transport).
Experts distinguish the following main types of independent suspension. (By the way, the photo will allow you to more clearly analyze their differences).

Suspension based on double wishbones

The structure of this type of suspension includes two levers attached to the body with silent blocks, and a shock absorber and a coil spring located coaxially.

MacPherson pendant

This is a derivative (from the previous view) and a simplified version of the suspension, in which upper arm replaced suspension strut. To date, MacPherson strut is the most common front suspension scheme for passenger cars.

Multi-link suspension

Another derived, improved version of the suspension, in which, as it were, artificially, the two transverse levers were “separated”. Besides, modern version suspension very often consists of trailing arms. By the way, multi-link suspension- This is the most used rear suspension scheme for passenger cars today.

The scheme of this type of suspension is based on a special elastic part (torsion bar), which connects the lever and the body and works on twisting. This type design is actively used in the organization of the front suspension of some SUVs.

Front suspension adjustment

An important component of comfortable movement is correct adjustment front suspension. These are the so-called steering angles. In colloquial speech, this phenomenon is referred to as "descent-collapse".

The fact is that the front (steered) wheels are not installed strictly parallel to the longitudinal axis of the body and not strictly perpendicular to the road surface, but with certain angles that provide slopes in the horizontal and vertical planes.


Correctly set "similarity-collapse":

• firstly, it creates the least resistance to the movement of the vehicle, and, therefore, simplifies the process of driving a car;
• secondly, it significantly reduces tire tread wear; thirdly, it significantly reduces fuel consumption.

Performing corner setting is a technically complex procedure that requires professional equipment and work skills. Therefore, it should be performed in a specialized institution - a car service or service station. It is hardly worth trying to do it yourself using a video or photo from the Internet if you have no experience in such matters.

Suspension malfunctions and maintenance

Let's make a reservation right away: according to Russian legal norms, not a single suspension malfunction is included in the “List ...” of malfunctions with which movement is prohibited. And this is a moot point.

Imagine that the suspension damper (front or rear) does not work. This phenomenon means that the passage of each bump will be associated with the prospect of body buildup and loss of vehicle controllability. And what can be said about the completely loose and worn-out ball bearing of the front suspension? The result of a part malfunction - “ball ball flew out” - threatens serious accident. A broken elastic suspension element (most often a spring) leads to body roll and sometimes an absolute impossibility to continue moving.

The malfunctions described above are already the final, most odious malfunctions of the car's suspension. But, despite their extremely negative impact on traffic safety, the operation of a vehicle with such problems is not prohibited.

An important role in the maintenance of the suspension is played by monitoring the condition of the car in the process of movement. Squeaks, noises and knocks in the suspension should alert and convince the driver of the need after-sales service. A long-term operation car will force him to apply a radical method - "change the suspension in a circle", that is, replace almost all parts of both the front and rear suspension.

The car consists of many nodes, each of which performs the functions assigned to it. without them precise work normal movement of the machine is not possible. One of the most important is the suspension of a car. It helps dampen impacts from uneven surfaces and transfers the torque of the wheels to the body. Thereby vehicle is moving in the right direction.

Attention! Without suspension, every hit when hitting a pit would cause serious damage to the body.

What is a suspension can be found in the video:

The purpose of the suspension and the general device

The suspension for a car has several basic functions that determine its role in the operation of a car. It is she who ensures the comfort of passengers when driving. One of its main elements are shock absorbers. They absorb the main impact force.

One more important function suspension is to hold the body of the car during cornering. This design feature provides high reliability even on the tightest turns. General device consists of the following elements:

• body;
• wheel;
• hinge;
• elastic, damping and guiding element.

Attention! Now in most suspension designs for cars, springs are used as an elastic element, but you can still find designs with springs.

good suspension auto provides smooth driving. It depends on her how comfortable you will feel on the track or off-road. In the process of evolution, automotive engineers have created many designs, each of which is unique. Many of them have found their practical application.

Types of suspensions and their device

There are many types of car suspensions. Each has a number design features which provides its functionality. It is not surprising that each design is determined for a specific class of machines, designed for certain operating conditions.

There are many types of pendants. Basically every serious automotive manufacturer he tried to invent his own unique design, which would maximally correspond to the class of cars produced by him. Listing them all would take too long. Therefore, it is better to focus on the most popular ones.

dependent suspension

Perhaps this is the oldest suspension that is still in use. Its main feature is a rigid connection. Similar effect can be achieved thanks to the beam and crankcase.

It is noteworthy that in the very first models, manufacturers even used springs. But soon this practice had to be abandoned. Modern counterparts are equipped with trailing arms. Transverse thrust is responsible for the perception of lateral force.

dependent suspension The car has the following features:

• low cost;
• low weight;
• good grip with surface.

At first glance, this is not so little, but the fact is that many other types of suspensions for cars have such qualities. The main drawback of the system is frequent drifts. In addition, due to the fact that the wheels move in different directions, there are problems with handling.

Rear semi-independent

The design of the suspension is quite simple. These are two trailing arms. They are interconnected by a cross bar. A similar suspension is installed only at the rear., on front-wheel drive vehicles. Otherwise, the effectiveness of the system is in question. The advantages of the system include:

• compactness;
• light weight;
• good cinematics.

The main condition for using this type of suspension is the presence of a non-leading rear axle. In some designs, shock absorbers and springs are installed separately.

Attention! The main alternative for a spring is a pneumatic element with a fixed value.

Even in some versions of the device, it is permissible to include springs and shock absorbers in one piece. In this case the pneumatic element is mounted on the shock absorber rod.

On trailing arms

This suspension for cars belongs to the class of independent. The main difference is the absence of a hard connection. Each wheel is held by a lever. It is he who takes the lateral forces.

Attention! The lever must have ultimate strength. This is the guarantee of the reliability of the entire device.

The lever is attached to the body with two hinges. At the same time, the element itself has a wide support base. Only in this way it becomes possible to provide the necessary fixation and reliability.

The suspension for a car of this type can only move longitudinally. In this case, the track does not change in any way. This design feature has both positive and negative side. If the car goes only forward, then there is a significant fuel economy. In addition, the body has increased stability, but as soon as the car enters a turn, everything changes dramatically.

Longitudinal suspension performs very poorly in corners. The wheels tilt with the body, and this, of course, does not contribute to stability. This type of construction has extremely meager opportunities for the transfer of lateral force. Large rolls are convincing evidence of this.

Adding a stabilizer to the longitudinal suspension device allows the car to get rid of excessive roll. Unfortunately, this addition leads to loss of stability on uneven surfaces.

It would seem that all the shortcomings listed above are more than enough to forget about longitudinal suspension for auto. But she has significant benefits which should not be forgotten. It is very compact and easy to install. Because of this, it is most often installed on buses and trucks.

Cross double levers

This suspension device for cars is a variation of the previous modification. It was created in the 30s of the last century. Despite this, it is still indispensable in the machines that take part in various types racing.

The wheel in such a suspension for a car is held by two levers, which are located transversely. Fastening can be carried out both to the body and to the subframe. Different automotive companies use the option that is most suitable for their purposes.

The main advantage of the transverse suspension for a car is the possibility of wide adjustment. You can easily change the slope of the levers if you need to. Thanks to this adjustment, the lateral roll parameter changes. Moreover, it is possible to change the length. This allows you to influence the collapse.

Lower arm transverse suspension for cars should be slightly longer than the top. Such a structural change allows the formation of a negative camber. Moreover, this happens with a minimum expansion of the track.

In practice, this will look like this: the suspension will grab the wheel from above. Because of this, when cornering, the wheels in front are much closer to the vertical. This effect can be achieved through negative camber. It is he who compensates for the slope, although not completely.

The distance between the transverse arms allows you to control the compliance of the suspension of the car. It also affects the kinematics. The dependency is pretty simple. The farther they are from each other, the greater the rigidity and the higher the accuracy.

Naturally, no cons transverse suspension auto did not work. Due to the changing camber, tires perform worse. This is especially noticeable when braking. Not surprisingly, over time, engineers began to install levers longitudinally.

Attention! The main advantage of a car suspension with trailing arms is the possibility of obtaining a roll center higher than that of other modifications.

De-dion

Looking for an opportunity to remove the load from the rear axle, scientists invented the suspension for the De-dion car. In it, the crankcase is separated from the beam. At the same time, it is attached directly to the body. Thus, the torque goes directly to the drive wheels from power unit. Half shafts serve as conductors. The structure can be dependent and independent.

Attention! Main disadvantage this car suspension is the lack of balance when braking.

The suspension plays one of the most important roles in auto. It is not surprising that automotive engineers have come up with many modifications, each of which is optimally suited for certain operating conditions.

On the video - an overview of the types of suspensions for cars: