GEAR PUMP AND OIL PUMP FOR AUTOMATIC TRANSMISSION USING THE SAME

摘要

A gear pump (1), wherein suction ports (5) are formed in a pump body (8) storing a pump gear (2) and a pump cover (9). Steps (8c) and (9c) extending in the rotating direction of the pump gear (2) are formed at the bottoms of the suction ports (5). The depths of the bottoms (8d) and (9d) of the suction ports on the inner peripheral sides of the steps (8c) and (9c) are set larger than the depths of the bottoms (8e) and (9e) thereof on the outer peripheral sides of the steps (8c) and (9c). Air bubbles in a sucked oil are collected to the inner peripheral sides of the suction ports (5) by the steps (8c) and (9c) and, when a part of the sucked hydraulic oil leaks from the inner peripheral side, the air bubbles collected to the inner peripheral side are forcibly and efficiently discharged to the outside together with the leaked hydraulic oil.