Disc Brake's Structure Optimization Based On Coefficient Of Variation

During the braking process, the inhomogeneous degree of distribution in contact pressure of the brake disc lead to the inhomogeneous distribution of the temperature and abrasion and reduces its service life. However, it is hard to describe the correlation between the structure and function by using traditional structural design. It is significant to study the inhomogeneous distribution in contact pressure for improving the stability in the braking process.In order to quantify the inhomogeneous degree in contact pressure and discuss its change with the structure parameters of the brake pad. The variation coefficient is introduced into the research and used to control the design of the brake. The variation coefficient can as a variable numbers to discuss the change law of the contact pressure with the structure of structure of the brake pad, and used to optimize the design ,in which stress in braking process can symmetrically distributed ,and to enhance the serve life of the brake pad.The results show that the variation coefficient is greatly influenced by the following parameters: the thickness, axis and radius lengths of the brake pad and the thickness of the brake. When the radius lengths of the brake pad increases, or the axis lengths of the brake pad decrease, or the thickness of the brake pad and the brake plane increase, the coefficient of variation will reduce. In the thesis, the optimizating regular the thickness of brake pad and the plane also are discussed. Results show that to increase the thickness of brake plane is more effective in improve the inhomogeneous degree of distribution in contact pressure than to increase the thickness of brake pad.Results show that to reduce the variation coefficient can significantly decreases the inhomogeneous degree of distribution,for example, when the variation coefficient reduces from 39.32% to 24.04%, the inhomogeneous degree of distribution in contact pressure decreases by 38.86%, meanwhile, the average contact pressure and contact area also increase, It is evident that brake efficiency of the brake pad can be improved.In the thesis, the brake pad temperature field has been investigated, and temperature distribution forms for different Structure have been achieved. The results showed that , by optimization , the inhomogeneous degree of distribution in contact interface temperature reduces from 43.61% to 28.11%, the degree of non-uniform temperature field also can improved and to reduce about 35.54% in contact pressure. At the same time, the temperature also presents a slower growth rate than before optimization.Finally, an experiment be carried out and a modal of the brake disc is developed and used to analyze the natural frequencies of the brake pad and other parts for avoiding the occurrence of resonance vibration. The results show that by the optimizing the structure of brake based on variation coefficient, the resonance frequency (which is 2100Hz) and shriek can be avoided by optimize design the brake.