1.3.2.2 Torsion Bars
Torsion-bars are mainly used in the suspensions of passenger cars and light commercial vehicles.
Torsion-bars are rods made of spring steel, that are predominantly stressed by torsion. These shafts are clamped at one end and free to twist at the other, so that the shaft can be twisted flexibly along its axis by a moment.
In order to use torsion-bars as vehicle suspension elements, the elastic twist of the bar is converted into a reciprocating motion with the help of a crank which is located at the swivel-free end and which applies the twisting moment, see figure.
The strut of the axle or the suspension forms the crank. Torsion-bars are normally arranged along the body-side bearing axis of the strut, at the opposite end of which the vertical wheel force acts as an external load.
The various equations related to torsion bars are indicated in the slide above.