A Study on the Effects of Piston and Finger Offset on the Pressure Distribution at Disk Brake Pad Interface 2005-01-0794
Generally, brakes with symmetric structures show symmetric contact pressure under static conditions. But under operating conditions, contact pressure becomes non-symmetric, which yields uneven wearing on the pad, and consequently results in poor NVH quality of disk brakes.
In general a symmetric brake shows high contact pressure at the leading edge of pad when rotor is rotating. To make contact pressure even, piston bore and caliper finger are offset to the trailing edge to compensate contact pressure at the leading edge.
In this study, estimation of the effect of offset of piston bore and caliper finger is performed by using ABAQUS standard. Two cases, conventional (symmetric) and offset type, are studied. The FE model consisted of hub, rotor, pad, pad back plate, piston, caliper and torque member (carrier). Contact conditions are defined for each part. Rotating condition is obtained by using the ABAQUS embedded function which is available in ABAQUS version 6.4.1. or later version.
Contact area, center of contact area, and contact force of both type (Symmetric type and offset type) are compared. Comparisons show improvements in contact pressure and contact force. Also, contact pressure of leading edge was predicted to become more uniform through the effect of offsetting the caliper structure.