Abstract
This study presents a method of preventing disk brake squeal by managing the distributions of pressure and stiffness on the frictional contact surfaces of the disk and the pad. Self-excited vibration is shown to be the cause of squeal, and it is generated when the coupled vibration of the disk and the pad becomes unstable. A surface contact analysis model is used to examine the squeal generation mechanism. The model is composed of a disk that has one degree of freedom (out-of-plane direction) and a pad-caliper that has two degrees of freedom (rotational and translational). The frictional contact surface is expressed as a distributed spring (contact stiffness). Analyses using this model clarify that squeal is generated when the contact stiffness is larger on the leading side than on the trailing side. The measurements of dynamic stiffness between the disk and the pad clarified that the contact stiffness become hared when the thrust pressure for braking become large. A squeal test was executed with experimental apparatus that can adjust the pressure distribution on the frictional contact surface. Squeal does not occur when the pressure distribution is kept uniform over the contact surface. The experimental results and calculations show that squeal can be decreased by making an appropriate thrust pressure for braking and keeping the stiffness distribution over the frictional contact surface uniform.
