The shock absorber - commonly, oil or gas-charged hydraulic dampers
The shock absorber is a safety-relevant component of motor vehicles. It dampens vibrations of vehicle’s sprung mass - and thus it is actually a vibration damper, which is why its name is misleading. In fact, the damping of shocks from potholes, bumps etc. is done by the suspension. The shock absorber and coil spring together make one piece: the so-called suspension strut. This strut is connected to the body by the strut mount or suspension strut bearing.
Gas pressure dampers and oil pressure dampers in the form of monotube or twin-tube shock absorbers.
Common types of shock absorbers include hydraulic oil or gas-charged devices. Both are provided with a piston rod in a cylinder filled with oil. Such hydraulic shock absorbers mostly consist of a piston that is guided on a piston rod within an oil-filled cylinder. When this rod is moved in the axial direction, the oil flows through corresponding orifices and thus creates pressure differences. As a result, the damping forces are generated. The damping during compression of the shock absorber is called bump or, more commonly, simply compression; damping force exerted during extension of the shock absorber is referred to as the rebound.
Unlike the conventional oil dampers, gas-charged shock absorbers contain gas. This is pressurized and prevents foaming of the oil, thereby ensuring increased performance under load. Furthermore, the gas has an (although small) additional damping function. Another difference exists between the mono-tube and the twin-tube shock absorbers. In contrast to the mono-tube shock-absorbers, twin-tube ones feature a separate compensation area into which excess oil can flow via a valve.
Worn shock absorbers make for a significant safety risk and are therefore considered a serious defect during the periodic vehicle inspection required by law. This is a sure way to fail this test. Thus, it is in your own best interest that a defective oil gas shock absorber is replaced as soon as possible.
Suitable parts, from the suspension strut bearing to the complete strut to the shock absorber, are available from Rexbo auto parts.
