Research On New Type Low-Resin Friction Materials And Optimization Design

With the progress of the society and the improvement of road conditions, the cars are running faster and faster. For the vehicle’s safety, comfort, higher requirements are put forward which is included not just reliability but also low noise, good abrasion resistance, stable brake, no hurt to the brake disc and environmental protection. By the end of 2014, China’s vehicle population amounted to 264 million, including 154 million cars. Brake pads for car supplies, has a very broad market. As to the problems of high content of resin such as high hardness, carbide on the wear surface and noise, the formula is put for the first time which includes a small amount of resin and nitrile rubber powder. To the problems of semi-metallic material such as high heat conductivity, hurt to the brake disc. This paper proposes the use of hybrid fiber and uses a small amount of metal fibers as the thermally conductive material to develop friction material. Analyze of the development of friction materials testing is to find the optimal combination of formula and process parameters combination.Firstly, orthogonal test is used to design formula. Constant speed testing machine, rockwell hardness tester, and compression testing machine are adopted to measure the friction and wear properties and mechanical properties of friction materials and to analyze the effect of different composition on the friction and mechanical properties. Combined with the fuzzy comprehensive evaluation method, the optimal formula is selected and the wear mechanism is studied by observing the wear morphology with SEM. The results show that resin effects on the hardness of friction material most, flake graphite effects of the friction coefficient most and coke effects the wear rate most. With the higher content of binder, the 8# specimen surface forms hard and dense carbonized film and vibration. The surface texture of 16# specimen is loose and porous and there is no light carbon membrane on the friction surface and no vibration during the wearing. Thus, resin can decreases the brake noise of friction material.The optimized formula is optimized again to obtain better process parameters. Orthogonal test is used to design process parameters. By the constant speed testing machine, rockwell hardness tester, and compression testing machine, the specimens are detected. The influence of process parameters on the material friction properties is analyzed and the optimal process parameters are filtrated. The products of the formula are tested on the car. The results show that shaping pressure has the greatest influence on the hardness, shaping temperature has the greatest influence on friction coefficient and wear rate. The optimized temperature is higher than before, but shaping time and heat treatment is shorter, which increases the production rate and properties, and shortens the time cost. During loading road test, the brake pads have good emergency braking and no braking noise and no hurt to the disc. After worn, the surface has high porosity and no light carbonized film. In total, low resin and material is good to decrease the braking noise,fade, disc hurt and high thermal conductivity.