Patent ID: 7140335

Claim:
A cam phaser for selectively adjusting the angular position of a camshaft relative to the angular position of a crankshaft to thereby alter the timing of valve operation in an internal combustion engine, the cam phaser comprising: a rotatable camshaft having an interior passageway, the camshaft including on an exterior surface thereof at least one cam operative to effect actuation of an engine inlet or outlet valve; a first drive member operatively connectable to a crankshaft for rotational movement therewith, the first drive member independently rotatably associated with the camshaft; and a piston member axially moveably disposed entirely within the camshaft interior passageway and associated with the camshaft for synchronous rotation therewith, the piston member further being associated with the first drive member for synchronous rotation therewith and axial movement relative thereto; and wherein the first drive member comprises a cam following portion in sliding engagement with a helical cam portion of the piston member, whereby axial movement of the piston member effects a change in the angular position of the first drive member as the cam following portion moves along the helical cam portion.