Patent ID: 6125806
Filing Date: 2000-10-03
Classification: F01L,F02B

Abstract:
A valve drive system for an engine provided with a combustion chamber defined at least in part by a cylinder head, and a plurality of poppet type valves disposed radially in said cylinder head with stems thereof defining skewed, reciprocal axes, said valve drive system comprising: a camshaft journalled for rotation about a camshaft axis in said cylinder head, said camshaft having a plurality of three-dimensional cams; and a plurality of rocker arms, each associated with a respective one of said three-dimensional cams and having a boss portion journalled for pivotal movement about a first axis upon a rocker shaft, a three dimensional follower portion engaged with the respective three-dimensional cam for effecting movement of said follower portion about a second pivotal axis relative to said three-dimensional cam, and an actuating portion engaged with the respective poppet type valve for operating said valves by the respective rocker arms through pivotal movement of said actuating portion about a third pivotal axis relative to the respective of said valves, said boss portions of said rocker being journalled on the respective of said rocker shafts for tilting movement in a direction perpendicular to its respective pivotal axis to provide line contact between said follower portion and said three-dimensional cam surface and said actuating portion and the respective valve, said boss portions of said rocker arms and the respective of said rocker shafts define a tapered cavity therebetween for permitting said tilting movement of said rocker arm relative to the axis of said rocker shaft.