| 摘要 |
PROBLEM TO BE SOLVED: To reduce the noise, the loss of power caused by frictional resistance, and the decrease of discharging amount caused by leakage in an internal gear-type oil pump. SOLUTION: A driving gear 30 of external teeth and a driven gear 31 of internal teeth engaged with each other are mounted in a gear chamber G defined in a casing H, and the operating oil is sucked from suction ports 20a, 20b and discharged from a discharge port 25a. A recessed groove 27 formed at a discharge port side of an inner peripheral face of the gear chamber to introduce the discharge pressure in the discharging port is located in a state that the resultant force of the force for pressing the driven gear in the radial inward direction by the discharge pressure inside and force for pressing the driven gear in the radial outward direction by the discharge pressure in the discharging port, acts in the direction to cancel the force added to the driven gear in the radial outward direction by the compression of the operating oil enclosed between teeth of both gears between a terminal end part of the suction port and a starting end part of the discharge port. COPYRIGHT: (C)2004,JPO
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