Patent ID: 8276557

Claim:
A variable valve activation system for internal combustion engines, comprising: a first arm driven to swing by a drive cam provided to a camshaft; a swing cam linked with the first arm being interposed by a link mechanism, the swing cam driven to swing by the first arm to thereby open/close an engine valve; and a variable mechanism for varying swing position of the swing cam with respect to the engine valve, and the variable mechanism continuously varying lift amount of the engine valve, wherein the first arm is rockably supported by a rocking shaft parallel to the camshaft, wherein the link mechanism includes a second arm, with a first end of the second arm being rotatably linked with the first arm by a connection pin and a second end of the second arm transmitting movement of the first arm to the swing cam through a link pin and a rod, wherein the variable mechanism includes a first gear provided concentrically with the rocking shaft of the first arm and a second gear provided with the second arm concentrically with the connection pin so as to mesh with the first gear, and wherein the variable valve activation system is arranged so that the rotation of the first gear causes the second arm to swing and vary the swing position of the swing cam with respect to the engine valve, while in a state wherein the first gear is in a stopped position and the engine valve is open, the first arm is caused to swing to thereby swing the second arm along an outer periphery of the first gear in a swing direction of the first arm about the connection pin.