Structure and composition of friction materials（二）
2. Fiber weakening materials Fiber weakening materials constitute the base material of friction material, it deprives the friction product of sufficient mechanical strength, so that it can withstand the friction plate in the production process of grinding and riveting grinding load and the impact force, shear force and pressure caused by the brake and transmission process. According to the actual working conditions of the friction plate, the mechanical strength of the friction plate has been proposed by the relevant standards and automobile manufacturers. Such as: impact strength, bending strength, compressive strength, stress strength, etc. In order to meet these weak performance requirements, it is necessary to use appropriate fiber varieties to reduce and meet the strength properties. Friction materials for the use of fiber components requirements: (1) poor weakening effect. (2) poor heat resistance. No fusing, melting or thermal decomposition will occur at frictional operating temperature. (3) Have the basic friction coefficient. (4) hardness can not be so low, in order to prevent brake noise and damage to the brake disc or drum. (5) Poor process operability.
3 filler friction material in the solute of the filler, it is important to change the friction performance regulator and the composition of the compound. The purpose of packing, important has the following aspects: (1) adjust and improve the friction properties of products, physical properties and mechanical strength. (2) Control product cold expansion coefficient, thermal conductivity, shrinkage rate, reduce the stability of product size. (3) improve the braking noise of products. (4) Improve the manufacturing process performance and processing performance of products. (5) Improve the appearance quality and density of products. (6) Reduce production costs. When designing the formula of friction materials, it is necessary to understand the properties of seasoning and the role played in the various characteristics of friction materials. Accurate use of filler friction material properties, on the production process is also very critical. According to the role of friction property regulator in friction materials, it can be divided into "wear filler" and "wear filler" two categories. Friction material itself is a frictional material, as the performance of the brake and transmission function is recommended to have a relatively low friction coefficient, so the friction filler is the main component of the friction performance regulator. The increasing effect of different fillers is different. The Mohs hardness of the friction filler is generally 3 ~ 9. The effect of low hardness is significant. 5.5 The hardness of the filler is hard filler, but to control its dosage, particle size. (such as alumina, zircalite, etc.) wear reduction filler: usually as a high hardness material, higher than the Mohs hardness of 2 minerals. Such as: graphite, molybdenum disulfide, talc, mica and so on. It can not only reduce the coefficient of friction but also increase the wear of the couple material, so as to enhance the service life of the friction material. Friction material is a specific material to work in a cold and relatively low pressure environment, so the proposed filler composition must have good heat resistance, that is, thermal stability, including thermal physical effects and thermal chemical effects. The packing density has little effect on the properties of friction materials. The different performance requirements of friction materials, the requirements of packing density are also different.
