PURPOSE: To obtain a camshaft free from cracking in ramping parts by regulating the amount of alloy powder to be allowed to adhere to the peripheral surface of a cam base material so that it is smaller in the ramp parts than in the other parts and also applying a laser beam to the above peripheral surface while rotating the cam base material on the shaft center.
CONSTITUTION: A sheet 7, e.g., of ferrous eutectic alloy powder prepared by kneading the above powder together with acrylic resin diluted with acetone is allowed to adhere to the peripheral surface of a cam base material 3. At this time, the amount of the alloy powder is reduced in the ramp parts 6 of the base material 3 so that the thicknesses of the sheet 7 are reduced in the ramping parts 6 as compared with those in the other parts. Subsequently, a laser beam 8 is applied to the surface of the base material 3 while rotating the base material 3 and the sheet 7 on the shaft center O of the base material 3, by which the base material 3 and the sheet 7 are successively remelted. At this time, the irradiation angle of the laser beam 8 is regulated so that it is smaller in the ramping parts 6 than in the other parts. By this method, an increase in the concentration of alloy components in the ramping parts 6 can be inhibited and, as a result, cracking in the ramp parts 6 can be inhibited.
MORISHITA TSUYOSHI
OSAKI SHIGEZO
OUCHI KATSUYA
