Patent ID: 7367297

Claim:
A valve train for an internal combustion engine, comprising: a valve operating cam rotating around a rotational center line in synchronism with a rotation of an engine; an engine valve including at least one of an inlet valve and an exhaust valve; a transmission mechanism for transmitting a valve drive force of the valve operating cam to the engine valve so as to operate the engine valve in open and close states, the transmission mechanism including; a primary oscillating member oscillating about a primary oscillating center line; a secondary oscillating member oscillating about a secondary oscillating center line through abutment with the primary oscillating member so as to transmit the valve drive force via the primary oscillating member to the engine valve, and a holder supporting the primary and secondary oscillating members thereon in an oscillatory fashion; wherein the primary and secondary oscillating center lines oscillate together with the holder, and a drive abutment portion of the primary oscillating member abuts with a follower abutment portion of the secondary oscillating portion; a driving mechanism for driving the holder so as to control valve properties including opening and closing timings and maximum lift amount of the engine valve in accordance with a position of the holder which is driven by the driving mechanism, wherein the holder oscillates about a holder oscillating center line which differs from the rotational center of the valve operating cam in response to the operation of the driving mechanism, a cam profile having a lost motion profile for maintaining the engine valve in the closed state by abutting the drive abutment portion with the follower abutment portion and a drive profile for driving the engine valve in the open state is formed on at least one of the drive and follower abutment portions, and in a sectional shape of the lost motion profile in a plane which intersects at right angles with the primary oscillating center line is an arc-like shape of which center is the primary oscillating center line.