| 摘要 |
PROBLEM TO BE SOLVED: To provide a rocker arm made of sheet metal, capable of effectively preventing abnormal abrasion and pitching in a valve stem sliding surface. SOLUTION: In the rocker arm 1 made of sheet metal, the hardness of a surface portion 9a of a valve stem retainer 9 is set to HV 650 to 800, and the amountγR of residual austenite is set to 25 to 35vol%. COPYRIGHT: (C)2005,JPO&NCIPI |
