US Patent 8695545 Phase changing device of camshaft

A phase changing device 100A of a camshaft is provided to a dual structure camshaft 10 which is rotated by a driving force input thereto and which includes an inner shaft 11 and an outer shaft 12. The phase changing device 100A of the camshaft includes a phase changing portion 1A including a single housing 2 defining: an advance hydraulic chamber R1 advancing wholly a phase of the camshaft 10 by a hydraulic pressure; a retard hydraulic chamber R2 retarding wholly the phase of the camshaft 10 by a hydraulic pressure; and a phase difference hydraulic chamber R3 changing a difference between a phase of the inner shaft 11 and a phase of the outer shaft 12 by a hydraulic pressure.