PURPOSE: To manufacture the titled cam shaft equipped with porosity for an oil pit at the circular part of a cam base by leaving the casting surface of the circular part of the cam base of the cast cam shaft intact, and remelting and hardening directly the casting surface.
CONSTITUTION: A cam top part 4 and a cam lift part 3 of a cam part 1 provided to a cast cam shaft is roughly ground by a cam grinder to obtain a roughly- ground surface 6, and the circular part 2 of the cam base is not ground and left intact as a casting surface 5. The cam part 1 is preheated to about 300°C, and rotated in the direction as shown by the white arrow (a). A plasma torch 11 is reciprocated and vibrated in the directions as shown by the arrows (b) and (c). Consequently, the torch is allowed to follow a zigzag course 7 from a start point 8 on the roughly-ground surface 6 to a finish point 9 on the casting surface 5, and the remelting and hardening is carried out. By said process, porosity for an oil pit can be formed on the circular part of the cam base simultaneously with the remelting and hardening of the cam surfaces 5 and 6.
IWAHASHI TETSUO
AZUMA MASAMI
| JPS58196362A | 1983-11-15 |
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