Patent ID: 7704061

Claim:
An oil pump, comprising: a plurality of pump chambers each having a volume varied by engine drive, the pump chambers pressurizing oil inhaled through an inlet port and discharging it through a pump chamber outlet port; a main passageway connected between the pump chamber outlet port and a housing outlet port; a branch passage connected between upstream and downstream sides of the main passageway at branch and confluent points, the branch passage being in a vicinity of the confluent point and being shifted in pulse-pressure phase with respect to the main passageway; and a pair of throttles, wherein the pair of throttles consists of throttles respectively provided at upstream and downstream end portions of the branch passage, the throttles being smaller in cross-sectional area than a general section of the branch passage which continuously extends and connects between the pair of the throttles between a branch point and a confluent point of the main passageway and the branch passage, wherein the throttles are provided, with respect to the main passageway and the branch passage, in the branch passage.