Valve operating mechanism including valve lifter

摘要

A valve operating mechanism for a reciprocating internal combustion engine. The mechanism comprises a valve lifter made of fiber reinforced plastic and including a cylindrical section. A partition section is integrally connected to the cylindrical section and located perpendicular to the axis of the cylindrical section. The partition section has a lower side at which an end portion of the valve stem of an intake or exhaust valve is to be pushed. At least one coaxial annular shim engagement projection is formed at the upper side of the valve lifter partition section. Each projection is formed with coaxial two shim contacting surfaces. A generally disc-shaped shim is disposed on the upper side of the valve lifter partition section. The shim has an upper side in slidable contact with a cam, and a lower side in contact with the upper side of the valve lifter partition section. At least one lifter engagement groove is formed at the lower side of the shim. Each groove is defined between coaxial two lifter contacting surfaces of the shim. Each projection of the valve lifter partition section is in fitting engagement with each groove of the shim so that the shim contacting surfaces of the valve lifter are respectively in contact with the lifter contacting surfaces of the shim, thereby uniformalizing and distributing an applied load over wide contacting areas between the valve lifter and the shim.