| 摘要 |
<p>PURPOSE:To improve lubricity and reduce sliding resistance by forming a film of a solid lubricant being formed on a cam surface only in a range receiving high face pressure out of the circumferential surfaces of a cam noze, and finishing the other circumferential surfaces yet smoother than a ground surface prior to film formation. CONSTITUTION:A cam nose part 11, whose one part is projected in the radial direction against a base circle 10, is formed in a cam 1 of a camshaft S. This cam 1 rotates centering on a rotation axis X and the cam nose part 11 comes into contact with a valve lifter 2 whereby rotary motion of the camshaft S is converted into reciprocating motion. In this case, a film 112 of a solid lubricant is formed only a high face pressure part Hp in a range where a central angle alpha, centering the center of the base circle 1 - from a projection end 111 receiving the highest face pressure out of circumferential surfaces of the cam nose part 11 to both ends in the circumferential direction is in a range of 15 degrees. In addition, other circumferential surfaces in the cam nose part 11 is finished to be yet smoother than a ground surface prior to film formation.</p> |
