Research On Dynamic And Kinematics Of Automotive Brake Vacuum Power System

Vacuum booster with brake master cylinder is one of the core components in the braking system,which has many parts and complex internal structure.This paper mainly analyzes its working process and performance from the perspective of dynamics and kinematics.The modeling basis and boundary conditions of dynamic kinematics analysis of vacuum assist system are studied,mainly including the working process and mechanical equilibrium equation of vacuum booster,the key performance parameters,the deformation characteristics of the feedback disc and air valve opening,the change relationship and the pressure change of the back cavity during the working of the vacuum booster;The relationship between the jump increase value of the vacuum booster system and the initial deformation of the feedback plate was studied.The hyperelastic rubber model of feedback disk is established in ABAQUS.The initial deformation is observed by adjusting the stress area and jump value of the main surface of feedback disk.It provides reference for adjusting the clearance between air valve and feedback disc.The working process of the main cylinder is analyzed,and the force of the second cavity piston assembly.By collecting the characteristics of the liquid demand of the influencing factors of the brake master cylinder and fitting it,combined with the force analysis of the brake master cylinder,the simulation model of the brake master cylinder force and stroke based on Matlab/Simulink is established.The force and stroke characteristics of the brake master cylinder,as the load of the vacuum booster,will affect the dynamic and kinematics analysis of the vacuum assist system.Based on the research on the performance of the vacuum booster and the brake master cylinder,the boundary conditions of the dynamics kinematics analysis model of the vacuum booster system are determined.The t hree-dimensional model of the vacuum booster is simplified and the assembly relationship between the components is determined.And the sports relationship,the virtual prototype model of vacuum assist system based on ADAMS was established.The simulation results show that the input and output characteristic curves of the vacuum booster system,which are close to the experimental results.Based on the virtual prototype model,the displacement,velocity and acceleration of the key components are analyzed.