| 摘要 |
PURPOSE:To form a tip to be brought into smooth contact with a cam and reduce wearing, by using a sintered metal material for the tip mounted to a contact part between a rocker arm and the cam. CONSTITUTION:A rocker arm 1 mounts a tip 3 to a part where the rocker arm is brought into contact with a cam 2. The tip 3 is prepared by molding and sintering to density ratio of 95% or more. The tip 3 under this condition of simple substance forms a contact surface (called a butt surface) with the cam 2 to be machined to a dimension and surface roughness of the rocker arm 1 when it is completed, providing a plating layer 4 of 5-50mu by electroless nickel plating. This nickel may be considered to be substantially composed of 90-92% nickel and 8-10% phosphor. In this way, a metallic coating layer, sufficiently forming by its initial wearing a familiarized surface with the cam, brings the tip into smooth contact with the cam. |
