The suspension on a vehicle is a relatively simple mechanical system. Basically, there are two springs on top of each other, which together carry the weight of the vehicle. The upper spring is the main spring of the vehicle, mounted in the suspension, and the lower spring is an air spring, namely, the tire. Usually, when the vehicle encounters a bump on the road, the softest spring (which is the vehicle’s main spring) is compressed and the suspension absorbs the bump, often without the driver being able to feel it inside the vehicle.
The disadvantage of this simple mechanical system is that it becomes unstable, the weight of the vehicle along with the springs can start to oscillate, and the vehicle is decidedly dangerous to drive because the tires and the entire vehicle become unstable.
Role of the shock absorber
To remove this instability, a shock absorber is used. The shock absorber is located together with the vehicle’s main spring inside the suspension. The shock absorber dampens the oscillation by removing the energy, thus removing the vehicle’s tendency for instability and thus improving the tire’s grip.
Disadvantages of the shock absorber
The use of shock absorbers also has some drawbacks. The disadvantage of normal shock absorbers is that they work best at low speeds. At very high speeds or ultra-high speeds, normal shock absorbers do not work well because they become too stiff and block the movement needed for the suspension to work. The fact that normal shock absorbers become stiffer and stiffer as the speed increases can be seen in their force-velocity plot.