US Patent 7946265 Valve timing adjuster

A supply control apparatus controls advancing supply, which is supply of working fluid to advancing chambers, and retarding supply, which is supply of the working fluid to retarding chambers. The supply control apparatus alternately and repeatedly executes the advancing supply and the retarding supply in such a manner that a rotational torque, which drives a camshaft, changes at a phase of cycle that is opposite from a phase of cycle of a variable torque, which changes with time and is applied to the camshaft, at time of limiting a phase of the camshaft relative to a crankshaft within a target phase range.