Types of leaf springs

Conventional leaf springs

Several identical leaf springs (spring layers) of different lengths are stacked in layers to form a spring package held together by a common center bolt and spring clip. Friction causes a desired natural damping between the layers during absorption, which previously even removed the need for vibration dampers. This effect can be reduced or enhanced by inserting plastic leafs or rubber buffers. 55Cr3 with tensile strengths of 1400 – 1700 MPa is generally used as spring steel.

Parabolic leaf springs

The special form and design of parabolic leaf springs allow the use of just a few relatively thick spring leafs. Their thickness is tapered from the centre to their ends in the shape of a square parabola (parabolic leaf springs). This allows each leaf alone to act as a flexural member with the same strength, while delivering ideal material utilisation. The advantages here are a low weight and a reduction in unsprung masses.

Composite leaf springs

Leaf springs made of fibreglass-reinforced plastic (FRP) are substantially lighter and possess greater durability than standard steel springs. We have provided FRP leaf springs for the Mercedes Sprinter van and the VW Crafter, among others, since as far back as 2005. In these types, each 5 kg FRP spring replaces a 25 kg steel spring, which accounts for weight savings of 80 %.