CAM SHAFT FOR DRIVING INTAKE AND EXHAUST VALVES OF INTERNAL-COMBUSTION ENGINE

摘要

PURPOSE:To prevent the generation of the creaking sound when the operation is stopped by providing a phosphate film to the bearing part of a cam shaft which drives the intake and exhaust vales of an internal-combustion engine so as to open and shut the valves thereby decreasing the fractional resistance of the bearing part. CONSTITUTION:The phosphate film, more preferably manganese phosphate film is provided to the bearing part of the above-mentioned cam shaft of the internal-combustion engine of which the intake and exhaust valves are drive to open and shut by the cams of the cam shaft. The above-mentioned film can be easily deposited and formed by dipping only the bearing part into a manganese primary phosphate soln. The frictional resistance on the surface of the bearing part is thus decreased by which the retentivity of a lubricating agent is improved and the surface roughness is decreased. The creaking sound arising from the resonant sound produced during the oscillation of the bearing part as a result of a stick-slip when the operation is stopped is eliminated.