SHIM FOR SOLID CAM, AND SOLID CAM MECHANISM FOR OPENING/ CLOSING VALVE

摘要

PROBLEM TO BE SOLVED: To improve the durability of a shim by setting the ratio of the hardness on the face side to the hardness on the back side of the shim in contact with a solid cam to be in a predetermined range to increase the impact resistance of the shim against the collision with the solid cam. ;SOLUTION: The appropriate ratio of the hardness of a semi-columnar surface to a cam contact surface of a follow-up contactor forming the shim is in a range of 0.4 to 0.85 in which both characteristics of the impact value and the tensile strength are high. The cam intact surface maintains the high hardness, and the follow-up contactor is surface-hardened so that the hardness of the semi-columnar surface is as low as 0.4 to 0.85 in terms of the hardness ratio. Thus, the follow-up contactor whose durability is not degraded even when the defective follow-up ability to the solid cam is continued for a long time at the high-speed rotation can be obtained without impairing the wear resistance. Since the toughness of the semi-columnar surface is increased, the impact resistance of the follow-up contactor against the collision with the solid cam is increased, and the durability is thus improved.;COPYRIGHT: (C)2001,JPO