Patent ID: 7581519

Claim:
A cam shaft phase adjusting apparatus for an internal combustion engine, comprising: phase shift device, which performs phase shift between a crankshaft and a cam shaft and includes advanced angle hydraulic chambers, which are increased in volume when a phase angle of the cam shaft relative to the crankshaft changes in a direction of advanced angle, and retarded angle hydraulic chambers, which are increased in volume when a phase angle of the cam shaft relative to the crankshaft changes in a direction of retarded angle; a plurality of advanced angle chamber oil path systems which are communicated to the advanced angle hydraulic chambers according to change in rotating angle of the cam shaft; a plurality of retarded angle chamber oil path systems which are communicated to the retarded angle hydraulic chambers according to change in rotating angle of the cam shaft; and a switchover device to switch communication and cut-off according to a rotating angle of the cam shaft such that one of the plurality of advanced angle chamber oil path systems is cut off from the advanced angle hydraulic chambers while the other of the plurality of advanced angle chamber oil path systems is communicated to the advanced angle hydraulic chambers, and one of the plurality of retarded angle chamber oil path systems is cut off from the retarded angle hydraulic chambers while the other of the plurality of retarded angle chamber oil path systems is communicated to the retarded angle hydraulic chambers.