Drum Brake Thermal-junction Coupling Analysis

At present, Automobile has been the most important transportation for people's travel, it's driving safety is one of the important indicators to measure the quality. Brake is an important part of the Automobile Braking System, it's braking ability determine the safety of automobile driving directly. The article research on the parametric design for drum brake, the static strength analysis for the key parts of brake, the thermal-structural coupling analysis based on a 470 series Drum Brake for a certain type automobile. The results and the definite work as follow:(1) Based on the Vechicle parameter of a certain type automobile, use the automobile brake system theory to calculate the performance parameter of Brake System and the structure parameter of the Brake System Key Part. At the same time, checking of brake ability, thermal capacity, temperature rise, and building the 3D model. Development the Design Platform for the Drum Brake based on the VB language. Build the template file according to the Car design theory and design experience. Parameterized the template file use the VB developing procedure and building the interactive channel between the procedure and the template file by inserting label on the corresponding location in word. At the last, realizing the parametric design for Drum Brake and building the design platform by packing the procedure and the template then publishing it as an application program.(2) Analysis the statics intensity of the Brake Key Part which include Brake Shoe, Brake Backing Plated and Brake Catch bracket, research on the displacement and stress nephogram we can find that; the maximum stress appear at the left bulge of the Brake Shoe, and the maximum is 247.3MPa, the maximum displacement inside the axle hole of the Brake Shoe which contact with the roller, and the maximum is 0.04869mm; the maximum stress appear at the left bulge of the Brake Backing Plate, and the maximum is 249.2MPa, the maximum displacement located on the upper end of the pin hole which contact with the Brake Shoe, and the maximum is 0.2496mm; the maximum stress appear at the back and right bulge of the Brake Catch Bracket, and the maximum is 372.8MPa, the maximum displacement located on the upper end face right of the top Brake Catch Bracket, and the maximum is 01.043mm;(3) In this paper, we analysis drum brake temperature field in transient thermal analysis finite element method. According to the law of conservation of energy and the law of Fourier heat transfer, heat conduction of the brake model is established. We take a research on the coupling between drum brake temperature field and stress field with direct coupling method. By comparing emergency braking and repeated braking, we can find that the distribution of brake drum temperature field and stress field is uniform in emergency braking. However, force and temperature concentration phenomenon will be obviously appeared after many times in a row under braking condition. This is because as the temperature increases, thermal stress deformation increases, residual stress superposition, resulting in local stress increases, the phenomenon of stress concentration and temperature concentration appeared. Finally, we take a research on the phenomenon of brake drum cracking failure. We selection the node at the crack location, study of the stress and the equivalent stress with the change of node location map, we found that node axial stress on the crack impact is the biggest, the flange plane of cracking is mainly due to cyclic stress.