Possibilities of Coil Springs and Fiber‐Reinforced Suspension Parts

Abstract

Abstract Helical compression springs (coil springs) have represented the best spring design for the vertical dynamics of passenger cars. They took over suspension functions and because of their advantages regarding weight and installation space they replaced leaf springs almost completely. This chapter contents a summary of conventional analytical as well as numerical methods of spring calculation. The numerical spring calculation and its usage for a new spring design with a homogenized stress distribution are shown. This new generation spring design is explained for the application on side load springs used in McPherson struts and rear axle spring where the spring seats deflect along a spatial curve. The new generation spring design offers a significant weight reduction combined with an increased robustness. The robustness of springs can be further increased using a method for improving the mechanical properties of the rim of the wire. The surface layer modification is using an inductive hardening and tempering process of the spring wire, which allows a hard core and a tough rim. Moreover, measures to improve the properties by alloying are described. Finally, this chapter contents the application of fiber composite materials for springs. While leaf spring is an optimal application for unidirectional glass fibers, suspension springs such as coil spring are not that much optimal because of complex stress situation and difficult geometry, which does not allow efficient and automated production methods.