Is It to Change the Spring or Absorb the Shock When the Car Is Not Smooth?

When the first car was designed, there were no springs or shock absorbers. It was not very smooth when one drove it and it made you very uncomfortable. So, people use four leaf springs to support the car body from the wheels to improve the comfort. However, when this design encounters a little bump on the road, the body will vibrate constantly. Therefore, people have designed a shock absorber to restrain the spring. The two complement each other and help to improve the comfort of the car. Nowadays, various structures have been developed.

The car suspension lift kit is of great importance in improving the comfort level of the car. According to the different parts of the body to support, it is divided into spring, steel plate, torsion bar, airbag and electromagnetism. The different structures can be divided into integrated type (such as Macpherson suspension, twisted tooth and airbag) and split type (separated spring and damper cylinder). The types of the cylinders can be divided into the oil pressure one and the air one according to the different filling materials while they can also be as single cylinder and double cylinders according to the structure.

The most common structure of damping is the use of spiral springs with cylindrical hydraulic shock absorbers, which, as an example, will be used to show the relationship between the two.

The spiral spring mainly supports the body and can buffer the external force, which, however, is unable to exhaust all the energy because of the structure. At the same time, it is easy to rock from side to side, which makes it difficult to ensure the driving stability of the car.

Thus, the shock absorber should come in handy. The function of the hydraulic shock absorber is to form damping through the friction between the valve wall and the hydraulic oil and the internal friction between the hydraulic oil molecules to convert the vibration energy into heat energy, which is then absorbed by the outer wall of the shock absorber and later emitted to in the outside air. The energy of the vibration is dissipated  by converting into heat energy, so that the force vibration will not be transmitted to the car body, and the passengers in the car will not feel that the car is particularly bumpy.

On the other hand, the structure of the shock absorber determines that it cannot support the body alone. Without the buffer of the spring, the potential energy generated by the beating body can hardly be consumed by the shock absorber in a short time and short distance. Therefore, the spring and the shock absorber must cooperate with each other to obtain a satisfactory effect.

According to the characteristics of the two, the timing of their action is slightly different. During the compression stroke, the spring plays the main role with the small damping force of the shock absorber to give full play to the elastic effect of the elastic element and alleviate the impact. The shock absorber plays a major role during the stretching stroke. At this time, the spring releases elastic potential energy, and the damping force of the shock absorber becomes larger, which quickly consumes energy to reduce vibration.

Both of them need to be coordinated with each other. For example, if the shock absorber is too soft, the body will jump up and down while if it is too hard, it will bring too much resistance and prevent the spring from working properly.

Therefore, when we feel that the shock absorber is too hard (or too soft), replacing the spring or shock absorber can achieve the purpose of improvement. But in actual operation, there will be some problems that need attention.

The first is the design of the spring structure, such as the rigidity, thickness, number of turns and spacing of the spring material, which will affect the bouncing of the body. For example, the greater the rigidity of the spring, the less likely it is for the body to jump, and the less the cushioning effect of the shock absorber is. The overall performance is that the body becomes harder and not easy to yield to pressure, and the comfort of the twisted teeth of the lower body is relatively hard. If the height of the vehicle remains unchanged but with the unchanged rigidity, the reduced number of turns and a larger spacing, at this time, the kinetic energy generated by the bounce will be mainly consumed by the shock absorber, which is easy to age and will soften the original shock absorber after a long-term use.

Next is the shock absorber structure, like the single and double cylinders and pure oil pressure and oil-gas mixture which are mentioned earlier, the comfort is finally decided by the adjustment of the internal damping value. A relatively soft spring coupled with a tough shock absorber will provide the sufficient comfort. The proper spring with hard shock absorber will hinder the normal operation of the spring, which will make us feel uncomfortable in the car.

Generally speaking, it is as if the spring determines the maximum and minimum comfort level, and the shock absorber determines the range of variation between this value. Take the twisted teeth as an example. It is supposed that your comfort level is 7. In order to support the body, the stiffness of the spring should be very large. The changing value varies between 2 and 6 according to different brands. The adjustable shock absorber itself can change between 1 and 12, but the final comfort level can only reach 6 at the maximum, which means that the spring determines the maximum comfort.

Of course, there are cases where the combination of the shock absorber and the spring is not applied. For example, the active suspension uses an airbag instead of a spring. The support force can be determined by the car owner, similar to the stiffness of the spring, and the damping force value in the shock absorber can be adjusted through the circuit, so that the car can be used in different situations where a better stability and comfort can be maintained.

According to the view of Sanlishin, the main function of the spring is to support the body, and the spring hardness of the original car is designed according to the weight of the factory. If it is too soft, it will easily cause the body to collapse. If it is too hard, it will not achieve the goal of improving the comfort. Therefore, when feeling that the shock absorption of the original car is too hard, it is a perfect solution to modify a set of adjustable shock absorbers which will adjust the damping force value of the shock absorber and ultimately improve the comfort according to different road conditions.