To reduce the leakage of operating oil, prevent the deformation of a cylindrical housing and improve operating responsiveness.
The cylindrical housing 8 having a sprocket portion 3 on the outer periphery is formed with sintering. A vane member 5 connected to a cam shaft 1 is stored and arranged in the cylindrical housing 8 and an advance angle hydraulic chamber 15 and a delay angle hydraulic chamber 16 are provided on both sides of a vane portion 14 of the vane member 5. The rotational phase of the cam shaft 1 with the cylindrical housing 8 is changed by properly supplying/discharging hydraulic pressure to the hydraulic chambers 15, 16. The whole cylindrical housing 8 is formed with sintering and then rolling is applied to the sprocket portion 3 to have higher density than a housing body. The deformation of the whole cylindrical housing 8 can be prevented by the sprocket 3 and the deformation due to the sintering be corrected during rolling.
TSUKADA TOMOYA
Hiromichi Kobayashi
Tomioka Kiyoshi