| 摘要 |
PURPOSE: To reduce the friction loss and improve the power loss by forming an adjusting shim used for the valve system drive of an internal combustion engine with a ceramic material having the maximum surface roughness of a specific value or below. CONSTITUTION: A valve lifter 3 is vertically driven by the rotation of a cam 2 to open or close an intake/exhaust valve 5 in the valve system of an engine, and a ceramic adjusting shim 4 is arranged on the top face of the valve lifter 3 to adjust a valve clearance. The adjusting shim 4 is formed with a ceramic material having the maximum surface roughness (Rmax ) of the contact face with a cam at 2.0μm or below, preferably 0.8μm or below, and more preferably 0.2μm or below. The ceramic material mainly made of silicon nitride is used. |
