| 摘要 |
PROBLEM TO BE SOLVED: To prevent wear of a seal member in a vane-type valve timing control unit of an internal combustion engine. SOLUTION: Between a displacement velocity (retarding velocity) which retards a relative rotation angle (rotation phase) of a cam shaft at a suction side against a sprocket 11 and a displacement velocity (advancing velocity) which advances it, a retarding angle velocity becomes greater than an advancing velocity due to a difference of operating friction. Thus, wear of a sealing member advances at a slow angular speed. Therefore, a changed section of a passage area is provided in a retarding hydraulic pressure supply passage 156 in a journal section, and a pressure loss in a flow direction of oil at the retarding angle becomes greater compared to a pressure loss in a flow direction of oil at the advancing angle in the retarding hydraulic pressure supply passage 156, so that a retarding velocity, namely, a sliding velocity of the seal member is suppressed.
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