Research On Torsional Vibration Characteristics Of Disc Brake Pair Considering Interfacial Particle Flow

With the popularity of automobile,the problem of vibration and noise of automobile braking is becoming increasingly prominent,and gradually becomes the focus of attention.In addition,due to the introduction of the outside world and the generation of self friction and wear,there must be many third body particles between the brake pairs.These third body particles have different shapes and properties,which often bring many uncertain factors in the braking process,resulting in more complex friction behavior of the brake pairs.Therefore,this paper will consider the influence of the third body particles to explore the vibration and noise phenomenon of the braking system(1)Based on CEB model and H model,a three-body coupling friction model is established,which considers the characteristics of rough contact surface topography and third-body particles.The contact surface is divided into two-body region with surface-to-surface contact and three-body region with surface-to-surface contact.The three-body coupling friction model was numerically analyzed,and the effects of pressure,particle size and density of the third body on the contact surface gap and the two-body and three-body regions were explored respectively.From the microscopic interface point of view,the action rules of various factors on the friction characteristics of contact pairs were found,and finally the effects of the above factors on the friction coefficient were explored.(2)A two degree of freedom torsional vibration model of disc brake pair is established.Combined with the three body coupling friction model,a coupling dynamic model considering ’brake disc particle flow brake pad’ is established.Firstly,the influence of the particle size and particle density of the third body on the vibration characteristics of the system is explored,and it is found that larger particles are conducive to the stability of the system;secondly,the influence of braking pressure and excitation angular velocity on the vibration characteristics of the system under different particle sizes is explored,and it is found that the effect of braking pressure and excitation angular velocity on the vibration characteristics of the system is different with different particle sizes.(3)On the basis of two degrees of freedom,the torsional vibration model of disc brake pair with four degrees of freedom including brake disc,brake pad,transmission subsystem and tire is established.The influence of particle size and particle density of the third body,braking pressure and excitation angular velocity under different particle sizes on the vibration characteristics of the system under the coupling action of the system is further analyzed,and compared with the results of two degrees of freedom.