| 摘要 |
PURPOSE:To manufacture a piston ring having improved wear resistance by rotating a piston ring in the peripheral direction and irradiating laser beams on the upper and lower faces of the ring so as to harden simultaneously both the faces of the ring without lowering the flatness. CONSTITUTION:A piston ring 1 is fixed in a guide ring 2 and rotated in the peripheral direction at a constant speed with a driving roller 21. Laser beams from a laser beam generator are converged through a condenser 11, divided in two directions with a prism 12 and irradiated on the upper and lower faces of the piston ring 1 through reflecting mirrors 13 to harden simultaneously both the faces of the ring 1. The guide ring 2 is preferably made of a metal having high heat conductivity such as copper so as to cool the piston ring 1. Thus, the hardening can be carried out with little change in the flatness. |
