Research On The Key Technology Of Automobile Brake Fatigue Test Bench

Brake is an important part to ensure safe running and reliable parking of the car, else the fatigue test is an important index to evaluate the performance of the brake, so brake fatigue test bench is one of the indispensable equipment in the research process of the brake. It is very consistent with the engineering requirements of the brake research to design a kind of fatigue test bench which can meet the requirements of the enterprise itself and can accurately simulate the braking condition of the brake. In this paper, brake fatigue test bed was studied and designed, besides, optimization and temperature field analysis and fatigue analysis were carried out for the key components. Details are as follows:First, the brake fatigue test bench was designed through the research of the composition, advantages and disadvantages of the existing brake fatigue test bench. Besides, cooperation company’s requirements were considered during this process. Fatigue tests not only the disc brake’s but also the drum brake’s could be completed through changing the fatigue test fixture.Second, Lightweight design for this fixture was studied via orthogonal test under a better strength and stiffness condition. The influence of different factors on the weight of single index was studied by using the multi factor-single index analysis method. Then, the orthogonal test results were weighted by using the multi factor-multi index analysis method. At last, the optimal result was obtained.Third, the optimized fixture was analyzed under normal temperature conditions by using the finite element software. The result showed that the stiffness of the fixture was improved by 15% after improvement. Analysis on temperature field of brake’s fixtures was carried out. On top of this, the influence of material and temperature on the strength of the brake was discussed. At last, a method of controlling the position of the brake in the process of fatigue test was presented based on the characteristics of thermal expansion of metallic materials.Fourth, fatigue analysis of brake’s fixtures was carried out based on FEMFAT/BASIC module. Influences of material and temperature on the fatigue life of the brake were studied. Results showed that the fatigue damage values of different materials are very different under the same condition. The fixture for 18Cr2Ni4 W material was worked under the condition that the braking torque is 40000N·m and the cyclic load is 400000 times. In the range of minus 40 degrees to 150 degrees, the fatigue damage value of fixtures was very small when the test temperature is below 120 degree, but when the test temperature is above 120 degree, the influence of temperature on the fatigue life of the fixture was very obvious.