| 摘要 |
PROBLEM TO BE SOLVED: To minimize generated torque and the wear of a sliding part and improve a fuel consumption of an engine, by forming a shim with harder material than a cam sliding face and by finishing a shim sliding face so as to have a specific average surface roughness, in the combination of the shim and the cam used in a reciprocating mechanism. SOLUTION: In an intake/exhaust valve of a reciprocating drive type, a valve 2 is reciprocated along the profile of a cam 1, and a shim 5 is seated on a recess part 4a formed on the edge surface of a valve lifter 4, and the integrated error of parts is compensated by adjusting the thickness of the shim 5. In this case, the shim 5 is formed with harder material than a cam sliding face, and a shim sliding face is finished so as to have a ten-point average surface roughness Rz in the range of 0.07-0.2μm, and also an opening air hole 1b is formed on the sliding face of the cam 1. Also, the shim member is formed with ceramics such as silicon nitride, and the cam member is formed with an iron-based alloy sintered body, and especially the shim member may be formed by giving a coating film of ceramics such as a nitride or a carbide of Cr or Ti on the surface of metal alloy material. |
