Twist beam axle
The twist beam axle is a type of rear axle in front-wheel drive automobiles . The construction is widespread in the compact class, with small and occasionally also with middle class cars; it was introduced by VW with the Scirocco and Golf I and used up to the Golf IV. For cost reasons, it will be installed again in the VW Golf VII with engines below 93 kW (122 PS).
The wheel suspension consists of two drawn longitudinal swing arms , which are connected at the front near their axis of rotation by a welded profile. The profile typically has a U- or T-shaped cross-section and is dimensioned so that it twists when it springs back and forth and acts as a stabilizer .
In the similarly structured coupling link axle , the trailing arms are connected roughly in the middle via a U-profile open at the bottom with a welded-in torsion tube (example: Audi 50 ). If the profile connects the trailing arms at their end, one speaks of a torsion crank axle (example: Audi 100 ). Kinematically this axis corresponds to a rigid axis.
Twist- beam axles are attached to the body with only two bearings and consist of very few individual parts, so they can be manufactured inexpensively. The weld seams between the rocker arm and torsion beam are exposed to high stresses and are therefore difficult to manufacture.
Compared to rigid axles, twist beam axles have the advantage that the deflection on one side on a bump results in significantly less movement of the wheel on the other side. The disadvantage is the tendency to oversteer the side force and the strong roll camber (the wheel remains parallel to the vehicle center plane).
All three rear axle constructions belong to the semi-rigid axles and are therefore not independent wheel suspensions .
See also
Suspension # Composite suspensions: semi-rigid axles