Braking Stability And Noise Characteristics Research Of Disc Brake’s Joint Surface

Vibration friction and noise are widespread in people’s daily lives.Among of them,vibration friction in rotary motion is closely linked with people’s production and lives.Planes,trains and automobiles braking system,cutting operation,drilling operation,polishing operation,rotating tunneling and reading of file in hard disk are rotary motion which contains the vibration friction phenomenon.The friction between rotary joint surfaces of mechanical systems tends to cause vibration and noise.The relationship between vibration and friction is mutual coupling.The understanding of vibration friction and noise characteristics will be deepen based on the study which towards the vibration friction phenomenon and noise characteristics of the rotary joint surface.Then a certain theoretical foundation for solving the vibration and noise can be provided in this paper.In order to study the vibration friction and noise characteristics of rotary joint surfaces,the disc brake of vehicle which is common in daily life is chosen as the research object in this paper.The dynamic characteristics of vibration friction and noise during vehicle’s braking are researched through dynamics modeling,numerical simulation,complex modal analysis and experiment.This paper focused on the system parameters which have an effect on the stability as well as noise of braking system.The effects were explored then.The study in this paper can provide guidance for braking system’s design,material selection and optimization.The major research contents of this article are as follows:(1)The current state and existing problem of braking system’s vibration friction and noise phenomenon at home and abroad are summarized and the classification and characteristics of the braking system were introduced which is based on a vast amount of literature.Then the purpose,background as well as significance were put forward.(2)The six different dynamic models of the disc brake were established.Then the five degrees of freedom dynamic model considering rotating was chosen as researched object through compare.The effect of system parameters such as stiffness,damping,rational speed and braking pressure on the braking stability was mainly explored through numerical simulation.The time history and phase locus of brake disc and friction plate under different parameters were obtained.Then their stick-slip and vibration phenomenons were analysised.(3)The unstable mode and natural frequency which can produce braking scream were obtained through complex modal analysis.The brake pressure and braking time wre obtained through braking condition analysis.Then the effect of system parameters such as elasticity modulus,friction coefficient,rational speed and braking pressure on the braking scream was mainly explored.The method of inhibition of braking scream was put forward.(4)The braking system experiment bench was established under joint efforts of teachers and students.The vibration and noise of braking system under different conditions was studied by braking system experiment bench and B&K test system.The relationship between vibration amplitude and braking condition in the X,Y,and Z axes directions was mainly analysised.The results show that:There are obvious stick-slip phenomenons between brake disc and friction plate at low speed.There is obvious flutter phenomenon in their displacement and velocity curves.The time required for system to reach steady state can be reduced by increasing the system damping and brake pressure or reducing the stiffness of the system.The amplitude can be decreased by increasing system damping and reducing brake pressure.The possibility of braking scream can be reduced by increasing the stiffness of friction plate and reducing the stiffness of the brake disc.