Method for finishing cam surface and device thereof

Abstract

The invention provides a method for finishing a cam surface and a device thereof, and relates to the cam surface finishing technology for an internal combustion engine. The method comprises the following steps: a cam is connected with an anode of a constant-current DC power supply; an electrode is connected with a cathode of the constant-current DC power supply; neutral electrolyte is filled between the anode and the cathode; a passive film which prevents the metal on the cam surface from being dissolved by DC current is formed on the cam surface after electrification, a microscopic high-spot passive film on the cam surface is removed by whetstone polishing to expose the microscopic high-spot metal, so that the metal is dissolved by DC current and the passive film is continuously generated; a microscopic low-spot passive film on the cam surface cannot be removed by whetstone polishing, the microscopic low-spot continuously exists, and the microscopic low-spot is protected from being dissolved by the DC current; and the passivation-activation process is repeated to ensure that the cam surface is finished to a mirror surface. The roughness of the cam surface after finishing can be further reduced to Ra0.10mu m, and the accuracy of the cam can be maintained.

Description

technical field [0001] The invention relates to a smoothing processing technology for the cam surface of an internal combustion engine. Background technique [0002] The camshaft is one of the key parts of the diesel engine, it controls the intake, oil supply and exhaust process of the diesel engine, the reliability of the camshaft is directly related to the normal operation of the diesel engine and the safe operation of the locomotive. The vast majority of domestic cam production adopts the process of "milling shape → rough grinding → heat treatment → fine grinding" for cam processing. Since the cam curve is composed of several simple or complex curve connections, the cam profile is irregular, resulting in a sharp "jump" of speed and acceleration, and the instantaneous speed of the grinding point, the contact arc length of the grinding wheel and the workpiece, and The polar coordinate position of the grinding point relative to the cam center changes with the shape of the c...

AI Technical Summary

Problems solved by technology

Since the cam curve is composed of several simple or complex curve connections, the cam profile is irregular, resulting in a sharp "jump" of speed and acceleration, and the instantaneous speed of the grinding point, the contact arc length of the grinding wheel and the workpiece, and The polar coordinate position of the grinding point relative to the cam center changes with the shape of the cam curve, which makes the grinding force, elastic deformation of the grinding wheel and workpiece system, and grinding heat constantly change, which can easily cause cam grinding defects - Grinding cracks and burns

Using a cam grinder with a profiler for fine grinding is prone to grinding defects, while using an imported CNC cam grinder is not easy to produce grinding defects, but imported CNC cam grinders are expensive, approaching tens of millions of RMB

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