| 摘要 |
PROBLEM TO BE SOLVED: To improve control response of valve timing by increasing an operating speed of phase conversion means. SOLUTION: This device employs a vane 3 that is located between a housing 6 of a timing sprocket and a camshaft and that is rotated either in a forward or a backward direction through a supply and a discharge of relative hydraulic pressure to and from an oil chamber 32 on an advance end and an oil chamber 33 on a retard end, thereby converting a relative circular-motion phase of the two members. A shut-off mechanism is installed in a midway point in a first hydraulic circuit that supplies hydraulic pressure to the oil chamber 32 on the advance end, in which shut-off surfaces 20a to 20d formed on an outer peripheral surface of passageways are used to plug and block off open ends of the first oil passages 52a to 52d in a region, at which a rotary fluctuating torque of the camshaft reaches its peak.
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