| 摘要 |
A piston ring is to be mounted in a groove in a piston. The piston ring has sidewalls for engaging sidewalls of the piston ring groove. Each of the sidewalls of the piston ring is hardened in respective localized areas. The localized areas each include a band of hardened material extending around each respective sidewall of the piston ring near the outer periphery of the piston ring. The hardened areas terminate short of the outer periphery of the piston ring. The piston ring due to the termination of the hardened areas short of the outer periphery of the piston ring has unhardened side surface areas immediately adjacent the outer periphery thereof for location adjacent the corners of the piston ring groove at the outer periphery of the piston. The localized areas are hardened by moving a piston ring blank relative to a laser beam, after the piston ring blank is machined. |
