Abstract

A cam follower device which is incorporated in a valve driving mechanism for an engine to contact the outer peripheral surface of a cam secured to a cam shaft that rotates synchronously with a crankshaft of the engine, thereby transmitting the motion of the cam to a valve that opens and closes a suction port or an exhaust port in the enigne. A ring-shaped member which contacts the cam is formed from a ceramic material, and this ceramic ring-shaped member is rotatably supported around a steel shaft. The clearance between the inner peripheral surface of the ceramic ring-shaped member and the steel shaft is set within a specific range, thereby preventing the occurrence of problems, for example, noise, arising due to a difference in thermal expansion coefficient between the two members and thus improving the high-speed follow-up performance of the cam follower device.