Patent ID: 7308874
Filing Date: 2007-12-18
Classification: F01L,Y10T

Abstract:
1. A valve drive mechanism for actuating a valve of an internal combustion engine, the valve drive mechanism comprising: a camshaft rotated by a crankshaft of the internal combustion engine; a cam provided on the camshaft; a swing member support shaft that is coaxial or in parallel to the camshaft; a swing member pivotally supported on the swing member support shaft, the swing member configured to be actuated by the cam for reciprocal motion; a roller follower that is configured to be actuated by the swing member for reciprocal motion to open and close the valve; and a spring member; wherein the swing member rocks within a predetermined range about the swing member support shaft, and the roller follower reciprocates within a predetermine range in synchronization with the swing member; wherein one of the swing member and the roller follower is provided with a roller for causing the roller follower to move in synchronization with the rocking motion of the swing member, and the other is provided with a contact surface that contacts the roller, the contact surface including a base circle portion and a lift portion; wherein when the roller contacts the base circle portion, a gap for absorbing errors or thermal expansion of respective portions of the valve drive mechanism system exists between components on a downstream side in a force transmission path with respect to a contact portion between the roller and the cam surface; and wherein the spring member brings the roller and the contact surface into constant contact with each other during the reciprocating motion of the swing member and the roller follower.