Development of L-Shape Coil Spring to Reduce a Friction on the McPherson Strut Suspension System

As for the McPherson strut, a force from the tire acts on the shock absorber producing a bending moment, which causes an increase in the friction acting on the shock absorber. Reducing the friction is one of the most important issues to improve the riding comfort of an automobile. The bending moment can be reduced by controlling the load axis of the coil spring assembled with the shock absorber. In order to control the load axis, several types of coil springs have been recently reported. This paper proposes another shape-controlled coil spring, called L-shape. The L-shape spring has the following advantages: (1) The load axis can be precisely controlled with ease; (2) Additional space is unnecessary; (3) Manufacturing tractability is increased. The proposed L-shape spring is validated analytically and experimentally in this paper. The effect of the L-shape spring for reducing the friction on a shock absorber is also experimentally confirmed.