Patent ID: 7707980

Claim:
A variable valve actuation mechanism for an internal combustion engine, the mechanism comprising: a drive shaft which rotates in operative association with rotation of a crankshaft, thereby to drive an intake or exhaust valve to open or close by way of a rocker arm; a control shaft which is rotated by driving a control shaft actuator and which causes variation of a position of the rocker arm, thereby causing a lift characteristic of the intake or exhaust valve to be continuously variable; a flange portion protruding from an outer circumferential surface of the control shaft configured to regulate movement of the control shaft in an axial direction thereof, a stopper protrusion which protrudes from the flange portion; and a cylinder head rotatably supporting the control shaft, the cylinder head including a flange bearing portion which contacts the stopper protrusion, the flange bearing portion having a groove receiving the flange portion such that the flange portion is disposed in the groove so as to regulate the movement of the control shaft in the axial direction.