In automobiles, shock absorbers serve to absorbs the bumps and irregularities on the road surface. They also make sure that the tyres are in contact with the roads at all times. This is essential for reliable braking and steering action.
Shock absorbers are designed in many ways. The simplest shock absorber is a spring based one. The load of the chassis is transmitted through a spring to the axle. Both coiled springs and leaf springs are used in shock absorbers.
Leaf springs consist of strips of metals placed on top of one another and rivetted together. The energy of the shock is dissipated as heat as the strips rub against each other.
Hydraulic shock absorbers consist of a piston and a cylinder containing hydraulic oil. The piston pushes against the oil which is forced trough a small opening in the piston. The oil takes time to enter the opening due to its viscosity. The resistance offered by the oil serves to retard the movement of the piston and absorbs the vibration.