Users have higher and higher requirements for the quality of automobiles and their parts. As the key parts of automobiles, the quality of brakes and the reliability of their functions are particularly important. Oil leakage of the brake cylinder is one of the most prominent quality problems in auto parts, and it is a hidden quality problem. The manufactured products cannot find any problems in appearance, and there will be no oil leakage at the beginning of use. However, some products will experience oil leakage after using for a month or longer. This phenomenon occurs in many products. Everything happened.
It is difficult to solve this problem, and it is difficult to verify. In recent years, the author has conducted some explorations and studies on the oil leakage problem of the brake wheel cylinder, and obtained some results in terms of the key causes of the oil leakage of the brake wheel cylinder and the solutions. Experience and effective methods are now introduced as follows. Choose a reasonable finishing method for the cylinder bore of the sub-cylinder, and strictly control the roughness of the cylinder bore. There are two ways of finishing: rolling and Qi grinding.
Rolling processing is indeed a more advanced finishing process at present, but the sub-cylinder made of HT250, during the production of the blank, due to minor changes in the material, pouring, aging and other reasons, the partial hardness of the sub-cylinder blank will appear uneven. The rolling pressure is difficult to smooth the local hard spots. During the rolling process, the surface of the sub-cylinder hole will also increase the hardness, and the local contour peaks and valleys of the cylinder hole (the peaks and valleys will accelerate the wear of the sub-cylinder cup, damage the cup and cause oil leakage ), it will be more difficult to eliminate. In addition, due to the poor plasticity of the cast iron material and the sensitivity to notches, after calendering, the surface of the cylinder bore is microscopically jagged. During the use of the brake, the cylinder piston moves axially, and the lip of the cup is tightly pressed by high pressure. If the cylinder hole is moved, the axial groove will be drawn, which will lead to oil leakage.
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