1996 年 1996 巻 41 号 p. 19-26
In the Macpherson strut type suspension, a spring offset is frequently adopted to compensate the side load acting on the damper rod with the reaction force of a spring; this offset amount is determined based on the assumption that the reaction force is directed along the spring axis. However, this is valid only for close-coiled helical springs. For helical springs of usual design, the reaction force will have the component perpendicular to the coil axis, as often pointed out by many researchers.
Therefore, this component, that is the side force of the spring, should be taken into consideration to improve the riding comfort.
In this paper, we first investigated the specifications of the springs which minimizes the side force. Then we studied the effect of the tilting angle of a spring seat and of the kinematic condition of the spring on the side force.
In consequence, it was found that the side force periodically increases with decrease of the number of free coils, minimum values occuring at integer numbers of free coils. it was also found that the side force can be reduced by moving the upper seat of the spring in the direction of the side force acting on the upper seat. Moreover, we found that the side force is remarkably reduced by tilting the upper seat in a proper direction.