Suspension system spring working principle and modification method

The existence of the suspension system has two meanings: Isolate the unevenness of the road to make driving more comfortable; keep the tires in contact with the road when traveling on uneven roads. The improved suspension has only one purpose for the “speeding party” is to improve handling.
Coil springs are the most commonly used springs for suspension systems because they are easy to manufacture, efficient in performance, and low in price. The definition of a spring in physics is to store energy. When we apply a fixed force to the spring, it will deform. When we remove the force, the spring will have a tendency to return to its original shape, but the spring will shake when it rebounds. The amplitude tends to exceed its original length, and it will not slow down the free shock caused by the spring rebound until there is frictional resistance, which is usually the task of the shock absorber. The general spring is the so-called (linear spring), that is, when the spring is stressed, its compression deformation follows the physics (Hooke’s law): F=KX, where F is the applied force, K is the elastic force coefficient, and X Is the amount of deformation. For example, when a linear spring is subjected to a force of 40Kg, it will cause a compression of 1cm, and then every increase of 40Kg of applied force by 1cm will definitely increase the amount of compression. In fact, there are other pressures on the suspended springs. Even when the springs are fully extended, the springs are still under pressure to fix the springs on the car. In the traditional spring and shock-absorbing cylinder suspension design, the spring acts to support the body and absorb the impact of uneven roads and other forces on the tires. The so-called other forces here include acceleration, deceleration, braking, turning, etc. The force caused by the spring. What’s more important is to keep the tires in constant contact with the road during the vibration elimination process to maintain the tracking of the car. Improving the contact between the tire and the road is our primary consideration for improving handling. The main function of the spring is to maintain the comfort of the car and keep the tires in full contact with the ground. Using the wrong spring will have a negative impact on the driving quality and handling. Imagine if the spring is completely rigid, the suspension system will not work. When the car jumps up when encountering uneven roads, the tires will also completely leave the ground. If this happens when accelerating, braking or turning, the car will lose track. If the spring is very soft, it is easy to appear (sit on the bottom), that is, use up the travel of the suspension. If a sitting situation occurs during cornering, it can be considered that the spring coefficient becomes infinite (there is no compressed space), and the body will have an immediate weight transfer, resulting in loss of tracking. If this car has a long suspension stroke, it may be possible to avoid the situation (sit bottom), but the relative body will also become very high, and a very high body means a very high center of gravity of the body. The high or low has a decisive influence on the handling performance, so too soft shock absorbers will cause handling obstacles. If the road is absolutely flat, then we don’t need springs and suspension systems. If the road is rough, a softer spring is needed to ensure that the tire is in contact with the road, and the travel of the spring must be increased. The choice of spring hardness is determined by the ruggedness of the road. The more rugged the spring, the softer the spring, but how soft it is is a key issue. Usually this requires the accumulation of experience and is also an important issue for various car manufacturers and teams. Generally speaking, a soft spring can provide better comfort and maintain better tracking performance when traveling on a rougher road. However, when traveling on general roads, the suspension system will swing up and down, which will affect the handling. In a car equipped with good aerodynamic components, the soft spring will cause the height of the car to change when the speed increases, resulting in different handling characteristics at low and high speeds.

Modification of the spring

The modification of the spring is mainly to improve the controllability, that is, to use a harder spring or a shorter spring. The spring controls many factors related to the control, and the change of the spring will cause very complicated changes in the control characteristics. In terms of the increase in hardness, it can improve the suspension’s rolling restraint ability and reduce the rolling of the body when cornering. The reduction in vehicle height can also reduce the body’s center of gravity, reduce the transfer of body weight when cornering, and improve stability. The reduction in vehicle height can also take into account the aesthetic effect.