Combination body of shim and cam

摘要

In a combination of the shim 5 and cam 1 for use in a reciprocating mechanism portion, the shim 5 is made of a material having a hardness higher than that of the sliding surface of the cam 1 and the sliding surface of the shim 5 is finished to within a range of the surface roughness of RZ0.07-0.2 mu m in 10-point mean surface roughness and further the sliding surface of the cam 1 is provided with open pores 1b. In the above combination, the generated torque and the wear of sliding portion are minimized by selecting a shim member whose surface roughness is difficult to deteriorate due to plastic deformation by a injection pump contact with a mating member and corrosion by various impurities mixed in lubricant and the like, and providing the surface of a cam member with an oil film holding function so as to maintain fluid lubrication of the sliding surface.