VALVE TIMING CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To eliminate motional inequality of an inner rotor in the spark advancing and retarding directions, which is caused by rotation of a valve timing variable mechanism itself, in a valve timing control device for an internal combustion engine, and to enhance the control ability thereof as well. SOLUTION: A valve timing variable mechanism 11 is composed of a first rotor (housing) 28 and a second rotor (inner rotor) 29 located in the housing 28, integrally connected with an intake side cam shaft and incorporating three vanes 32, both rotors 28, 29 having one and the same center axis. The three vanes 32 each having left and right surfaces one of which is planar and the other one of which is stepped, partition the inside of the housing 28 into a spark advance side hydraulic chamber 13 (planar surface side), a spark retard side hydraulic chamber 14a and an air chamber 14b (stepped surface side). The valve timing is controlled by controlling the hydraulic pressure of the hydraulic chambers 13, 14a. The air chamber 14b is communicated with the outside of the mechanism 11 through vent holes 75.