| 摘要 |
PROBLEM TO BE SOLVED: To improve the wear resistance of a slide contact face to a cam without using a shim and a cam support by dispersing wear resistant particles into the surface layer of the slide contact face of a light metal tappet mainbody to the cam. SOLUTION: A tappet mainbody 4 which is formed into a circular shape with the closed upper face by cold forging aluminum alloy raw material has an iron based flame coated layer 5 on the outer periphery. Into an upward recess 6 formed at the center on the lower face of the top wall 4a of the tappet mainbody 4, a wear resistant metal chip 7 is fitted to put the axial end of an engine valve in contact therewith. Wear resistant hard particles 8 of size 10μm or less, e.g. are almost uniformly dispersed and embedded into the surface layer of the top wall 4a. It is suitable that the particles 8 are ceramics based powder containing Al2 O3 , ZrO3 or, etc., with a higher melting point than aluminum alloy, metal powder containing Mo, Si or, etc., with self lubricating ability or intermetallic compound powder containing CrSi2 or, etc. |
