Three dimensional cam, method and apparatus for measuring three dimensional cam profile, and valve drive apparatus

摘要

An engine valve drive apparatus. A camshaft rotatably supported by the engine includes a cam for selectively opening and closing a valve. The cam has a cam surface for driving the valve. The cam surface has a profile that varies continuously in the direction of the cam axis. A valve lifter is arranged between the cam and the valve to convey the motion of the cam to the valve. A cam follower is supported on the valve lifter. The cam follower includes a slide surface having a pair of edges. The cam surface is arched outwardly in the direction of the cam axis to prevent the slide surface edges from contacting the cam surface. The curved surface prevents damage to the cam surface and enables smooth sliding between the cam surface and the cam follower. Alternatively, the slide surface of the cam follower may be arched outwardly.