Abstract
Functions of suspension springs for automobiles are to keep maneuverability good and to improve comfortability in riding. Rally cars run winding or rough roads with high speed, which causes sometimes cars jumping. When the car jumps, clearances come out between suspension springs and the seats. Then the springs collide hard with the seats in the car landing, which may break the springs. So a spacer called 'helper spring' is inserted between the suspension spring and the seat, which fills the clearance and absorbs the impact forces from the road (Fig. 1). A rectangular wire helical spring is usually used for the helper spring, as it can deflect to a greater extent than a circular wire spring. Recently a new rectangular wire helical spring is contrived, in which the helper spring (Part A) is connected to the suspension spring (Part C) with a connecting spring (Part B) of a continuously changing the wire cross-section (Fig. 2). Namely the helper spring and the suspension spring are combined in a body. In this study the non-linear spring characteristics and the stresses of the springs are studied theoretically and numerically. Furthermore the Finite Element Analysis and experiments are carried out on some test springs to check whether the theoretical analysis is proper or not.
