Patent ID: 7699738

Claim:
An oil pump structure of a transmission comprising: a pump housing installed on the transmission and having a hydraulic pressure chamber; inner and outer rotors rotatably accommodated in the hydraulic pressure chamber; and a pump cover attached to the pump housing for hermetically covering the hydraulic pressure chamber formed in the pump housing to hold the inner and outer rotors in the pump housing, wherein a first inflow port communicating with an oil strainer and a second inflow port communicating with a control valve are formed in an outside surface of the pump cover separately from each other, wherein a first oil inflow passage communicating with the first inflow port and a second oil inflow passage communicating with the second inflow port, a merged-flow portion configured such that a downstream portion of the first oil inflow passage and a downstream portion of the second oil inflow passage are merged with each other, and a downstream-side oil distribution channel intercommunicating a downstream side of the merged-flow portion and the hydraulic pressure chamber, are formed in at least one of the pump housing and the pump cover, and wherein a flow passage area of the downstream side of the merged-flow portion is dimensioned to be greater than or equal to a summed value of flow passage areas of the first and second inflow ports.