Which is the most important part of the car? Almost all motorists will argue that, of course, the engine, since it is he who sets the car in motion. Others will say from the body, about the transmission. But no one will say about the suspension of the car. But this is the foundation on which the machine is built. It is the suspension that determines the overall dimensions and features of the body. It also affects which engine will be installed in a particular car.
The pendant is an important and complex knot. It requires detailed consideration.
Purpose and tasks
Car suspension (also called a suspension system) is a group of individual parts and devices that work closely together. Their main feature is to provide an elastic connection between the road and the car body. The suspension reduces the load on the sprung mass. In this case, the load is distributed alongthroughout the structure evenly.
In a modern car, the described system consists of the following nodes:
- Elastic elements that provide a smooth ride and reduce the effect of vertical dynamics.
- Damping element. It converts vibration loads into thermal energy, normalizes the dynamics of movement. A guide element in the suspension is needed to handle lateral as well as longitudinal kinetics on moving wheels.
Regardless of the type and design features of a particular car, car suspensions have a common task. It consists in dampening incoming vibrations and noises, as well as in smoothing out vibrations that occur when moving on uneven surfaces. But depending on the characteristics of the machine, the type of suspension will be different.
Regardless of the type of car suspension, it consists of basic elements and parts, without which it is difficult to imagine a workable mechanism.
Several main ones can be distinguished among them:
- Elastic buffer that performs the function of an analyzer. He works out the bumps in the road and transfers all information about them to the body. The composition of these nodes may include various elastic elements - springs, springs, torsion bars. They will smooth out vibrations while driving.
- Distributing parts. They are connected to both the suspension and the bodywork. This allows maximum transfer of effort. These include levers, tie rods and tandems.
- Shock absorbers that allowresist elastic elements. There are two types of shock absorbers - double-tube or single-tube. The classification also divides these units into oil, gas-oil and pneumatic.
- There is also a rod in the car's suspension device. It provides lateral stability and stabilizes the body. The bar is part of a complex complex of supports and lever systems that are attached to the body and are designed to distribute the load during various maneuvers.
- Fasteners are bolted connections and bushings. The most common fasteners are silent blocks, ball bearings.
Types of car suspensions
The history of the first systems goes into the deep past. This is the beginning of the 20th century. Then the first solutions performed only connecting functions and all the kinetics were transferred to the body. But then, after numerous experiments, various developments were embodied in iron, which significantly improved the design and increased the potential for future operation. Until modern times, only a few types of car suspensions have been able to reach.
This system was developed by renowned design engineer Earl McPherson. This design was first used 50 years ago.
It is a lever, rack and anti-roll bar. This type is far from perfect, but at the same time it is affordable and popular - it is the choice of manufacturers for most front-wheel drive budget cars.
Double lever system
Here the guide block is not one, but two levers. The system can be either diagonal or transverse or longitudinal.
This design is more advanced, and therefore has a lot of advantages. It provides a smooth and even ride of the car, improved maneuverability. More often, such solutions are found on premium expensive cars.
This is a suspension of passenger cars similar in design to the above described types. But in this type, instead of springs, torsion bars are used, which, even in the simplest scheme, significantly expand the efficiency of the system. The components themselves are easier to maintain, and they can be adjusted as desired and according to the tasks that should be solved.
De Dion Pendant
This design, developed by French engineer A. De Dion, reduces the load on the rear axle of the car. Its main feature is that the main gear housing is fixed not on the bridge beam, but on the body. Such solutions are more common on all-wheel drive vehicles. On passenger cars, this suspension is contraindicated - subsidence is possible at the time of acceleration and braking.
This is a well-known version of the car's rear suspension. He was very loved in the USSR.
The beam in this design is attached with springs, as well as trailing arms. Despite the advantages of excellent handling and stability in motion, there is a drawback. This is a significant mass of the rearbeams.
Torsion link design
This is a hybrid of dependent and independent suspension. A torsion bar is used as an elastic element. One end is fixed to the body, the other - to the moving part. This design is widely used in most budget cars, as it outperforms the dependent system in terms of cost.
There are also semi-independent rear suspensions. In these solutions, a cross member is used, which is connected using two trailing arms.
Swing axle suspension
This type is based on semiaxes. Hinges are attached to the end of them, and the axles are articulated with tires. When the wheel is moving, it will be at a 90° angle to the axle shaft.
Trailing arm suspension
Designs are divided into torsion and spring. Among the main differences, the wheel is located almost next to the body. They use such solutions on small cars and trailers.
Trailing and wishbone designs
This car suspension is based on trailing arm. It is designed to unload the support forces that are exerted on the body. This type of suspension is very heavy, making it unpopular in today's market.
In the case of the transverse arm, everything is much better - the design is flexible with a good and competent setting. Support arms reduce stress on system attachment points.
Suspension with oblique arms
Structurally, it is very similar to the trailing arm design. The difference is that the axles in which the levers swing are hereare at sharp angles. Such types can be found on the rear axle of German-made cars. If we compare this suspension with the design, where the levers are longitudinal, then the rolls when turning with oblique levers are lower. This is a big plus.
Double wishbone and trailing arm suspension
Unlike single-lever designs, this type has two levers on each axle. They are placed transversely or longitudinally. When connecting them, springs, torsion bars or springs can be used. Suspension is compact, but unbalanced if you need to move on bad roads.
Pneumatic and hydropneumatic suspensions
Double wishbone systems are most often used in the air suspension of a car. It is not considered an expensive option, but it greatly increases driving comfort.
Pneumatic and hydropneumatic type are complex devices. But it provides a very smooth ride, excellent handling, advanced vibration damping. The air suspension of the car goes well not only with multi-link designs, but also with simple ones, like MacPherson.
This is an even more complex design, based on an electric motor. This system solves two problems at once, replacing the shock absorber and the elastic element. The whole complex is controlled by a microcontroller device with a special sensor.
Suspension is safe, and mode switching is provided by electromagnets. This type has a highcost price.
Semi-active or adaptive
Here, the suspension adjusts completely to the road surface and the driver's driving style. It determines the level of damping and independently automatically adjusts to the desired operating mode. Adjustments are made with electric magnets or fluids.
Suspension systems for pickups, trucks and SUVs
When developing trucks, engineers used options where the axles are placed on transverse or longitudinal springs. Moreover, some manufacturers do not change this design, although progress has reached this area.
There are now models that use a fully hydraulic undercarriage. A distinctive feature of the described truck suspension are simple bridges that are attached to the body with a bracket and connected with springs.
On SUVs, as well as on pickups, everything is more complicated and can differ significantly from one model to another. This approach is explained by the need for increased cross-country ability. The designs are based on a spring suspension, although there are also spring solutions.
Diagnostics of the car's suspension should begin with lifting the hood:
- While the car is securely on the ground, inspect the condition of the upper supports. First of all, it is important here what is the gap between the cup and the body. If it is equal to about one and a half centimeters, then the upper pillows must be changed.
- Nextthe car is rocked. If it swings more than twice, it's time to replace the dampers.
- The car is raised and looked at the shock absorbers from the side. It is important that there are no smudges on them.
- Then they take the car by one of the wheels and shake it left and right, up and down. In the first case, knocks of steering rods or rod ends can be heard in the front suspension of the car. With the help of an assistant, you can find out the cause of the knock in more detail. You need to take a good grip on the steering rod and find out where the play is - in the steering rack or in the tip.
- If there are extraneous sounds when rocking the wheel up and down, then it's time to change the ball joint. But if there are no sounds, then it is not a fact that the ball is in order. It is better to make sure that it is working with a mount.
- The wheel is turning. This is necessary to find out the condition of the wheel bearing. Then the wheel is spun again, while holding the spring with one hand. If it vibrates, the bearing will soon fail.
- Silent blocks are checked using a mount under the car. They move in the longitudinal and transverse direction. A little play is acceptable, but no more. Strong wear of the ball joint can be noticed if you swing the lever near the ball joint with both hands - there should not be any backlash. These backlashes are also noticeable during the movement of the car. When turning the steering wheel, a characteristic knock is heard from under the front.
- At the end, they check the anti-roll bar of the suspension of a VAZ car - the condition of the bushings is important. The mount is pushed betweensubframe and stabilizer, and then pump. If the bushing is damaged, the stabilizer will walk in it. They also check how the stabilizer is fixed in the levers.
The process of diagnosing this node begins in the same way as in the first case. There are no ball bearings here, so you can immediately start with wheel bearings. Then look at the condition of the shock absorbers. That's it.
You can wait for some sounds from the rear suspension for a very long time - it is silent, due to its simple and reliable design. Rear suspension wear can only be felt by the terrible handling.
There are a lot of pendants. All of them are different, but in the majority - it's MacPherson. How to diagnose it in garage conditions is described above. But it is best not to trust your own feelings, but to go for computer diagnostics, because the suspension is one of the main elements of the car.