VALVE TIMING CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To smoothly release a lock after the starting and to prevent a vane 5 from being enlarged for the sake of a lock pin. SOLUTION: This valve timing control device is composed of a disc-shaped housing rotated in synchronization with a crank shaft, and a rotor 2 fixed to a cam shaft. The vane 5 extended in the radial direction of a rotor 2 is engaged in a recessed part inside of the housing 1, and a timing advance-side hydraulic chamber and a timing retard-side hydraulic chamber are defined at both sides of the vane 5. A tip part of the vane 5 is provided with an apex seal 11 for sealing a part between both hydraulic chambers with a seal spring 13. At the most retardant position of the rotor 2, the apex seal 11 is pressed to a plunger 19 and engaged with a lock hole 18. When the oil pressure supplied to a hydraulic port 23 becomes high after starting, the lock is released. Since both hydraulic chambers are communicated at that time by a channel 22 around a plunger 19, the rotor 2 is not energized in the rotating direction and smoothly released.