Performance Analysis And Research Of Drum Brake Based On Flexible Model

Vehicles quickly and widely used in various areas of society result from rapid economic growth and transit system construction and development,Such as logistics transport,passenger and people’s daily driving trip.Braking performance is one of the important performance that ensure the safety and reliability of vehicles,while brake is the main executive part of the braking process.Finding a scientific way to control the performance of vehicle brakes by means of in-depth study and analysis is the key factor to achieve active safety of vehicles and reduce traffic accidents The performance of a commercial vehicle drum brake is studied based on the flexible body model of multi-body dynamics.The main contents of the paper are:(1)The nonlinear relationship between the S-type actuating cam angle of the Archimedes spiral profile and the cam force on the brake shoe is analyzed.The relationship between the output torques of drum brakes actuated by Archimedes spiral cams is analyzed.Theoretical Calculation Method of Braking Torque of Brake Cam Actuating Characteristics is studied Based on Vehicle and Brake Related Parameters.After substituting the parameters,the output of pressure drum brake braking torque is calculated.(2)A three-dimensional structural model of drum brakes for commercial vehicles was established.The free-form modal analysis and constraint modal analysis of brake shoe,brake lining and brake drum of commercial vehicle drum brake are carried out in the software ANSYS,extracting mode shape and the corresponding frequency of drum brake components in the free state and installation state and the influence of each vibration mode on the performance of the brake is analyzed.The multi-body dynamics simulation of the flexible body is carried out by outputting the drum brake soft model from the MNF file to the multi-body dynamics analysis software ADAMS.(3)The process of rigid-flexible coupling model of drum brakes was studied.The necessity of modeling analysis using rigid-flexible coupling model is introduced and the multi-body dynamics analysis method is introduced.The three-dimensional model of drum brake is introduced in ADAMS,the constraint is added and the inertia mass property is set.The rigid body model of brake shoe and brake lining is replaced by the MNF file created by ANSYS.This paper studies the method of simplifying the inertia of the rotating parts to the brake drum and setting the friction restraint between the brake lining and the brake drum.The rigid-flexible coupling model of the commercial vehicle drum brake is established(4)According to the equivalent inertia calculation method of the brake drum,the relationship between the rotational inertia of the brake drum and the speed of the brake drum is calculated.The braking performance of the brake was analyzed under the defined emergency braking and continuous braking conditions.The influence of the motive force fluctuation on the flexible body model was also studied.The theoretical calculation model of drum brakes and the advantages and disadvantages of the rigid-flexible coupling model are compared from the aspects of modeling complexity,calculation speed and calculation precision.In this paper,the theoretical calculation model of brake performance and the performance model of braking performance based on flexible body are established,and the advantages and disadvantages of the two models are analyzed and compared.The characteristics of the brake cam,the modal characteristics of the brake drum and the analysis method of the rigid-flexible coupling model are studied in detail.The advantages and disadvantages of the two calculation methods are compared and analyzed.It is of practical significance for the research and improvement of brake performance.