Noise from progressive multi-leaf springs and methods for its reduction

Abstract

The noise produced by progressive multi-leaf springs was investigated. Experiments on progressive multi-leaf springs indicated that the source of the noise was contact between the main and help springs. The contact between the two leaves was examined by numerical simulations of spring deformation with changes in the applied external load; these simulations were carried out using ABAQUS. The parameters that potentially influence the unexpected noise in the progressive multi-leaf spring were investigated through a review of the structural characteristics of the spring. Two candidates were then selected as potential main parameters influencing the observed noise: impact by an abrupt contact and friction between the main and help spring leaves. Consideration of the results of numerical simulations, noise measurements and other observations led to the conclusion that translational jumping of the contact point between the main and help spring leaves is the main mechanism causing the noises emanating from the progressive multi-leaf spring. Based on this conclusion, modification of the shape of the help spring leaf is proposed to eliminate the abrupt contact caused by a jump of the contact position. Experiments showed that the tapping noise was successfully eliminated by modifying the shape of a help spring leaf without a noticeable change in the spring stiffness.