Patent ID: 7159549

Claim:
A variable valve system of an internal combustion engine, comprising: a camshaft; a plurality of cam lobes integral with and mounted on the camshaft and operating to open and close engine valves when the camshaft rotates, every adjacent two cam lobes being apart from one another by predetermined distances respectively; an annular vane member having a plurality of vanes that project radially outward therefrom and a circular opening that is sized to permit the cam lobes to pass therethrough; an annular housing housing therein the vane member in a manner to permit a rotation of the vane member relative to the annular housing, the annular housing having a circular opening that is sized to permit the cam lobes to pass therethrough; a drive power transmission mechanism that transmits a torque of a crankshaft of the engine to the annular housing; at least one pair of retarding and advancing work chambers defined between the annular vane member and the annular housing; and a hydraulic circuit that selectively feeds a hydraulic fluid to one of the retarding and advancing work chambers in accordance with an operation condition of the engine, wherein each of an axial length of the annular housing and an axial length of the vane member is set smaller than the shortest one of the predetermined distances, and wherein the vane member is tightly mounted on a given portion of the camshaft to rotate therewith.