Rubber suspension axle
The rubber suspension axle is a simple type of wheel suspension . It can be found on trailers and consists of two square tubes plugging into each other. The outer tube is firmly connected to the frame of the trailer. The smaller, inner square tube is rotated 45 degrees compared to the outer axle tube. Four rubber cords are pressed between the two tubes. A swing arm, which carries the wheel and the brake, is attached to the inner tube . During compression, the rubber cords are deformed and spring back. Because of their high internal friction, they also take over the damping to a certain extent .
In a variant, instead of the square inner tube, an essentially triangular inner tube is used, which is inserted into a hexagonal outer tube and is mounted in three rubber elements. This allows greater spring deflection, but leads to less faithfulness to track and camber.
A rubber spring axle constructed in this way (with a square tube or hexagonal tube) springs progressively, i.e. the more load acts on the axle, the harder the suspension becomes. This property is beneficial to driving behavior. Vehicles with a low dead weight and high permissible payload tend to "jump / hop" when unloaded when driving.