Patent ID: 8496303

Claim:
A pump assembly comprising: a housing; a pump unit accommodated in a pump unit receiving portion which is formed in the housing, the pump unit having a low pressure portion and a high pressure portion therewithin; a suction passage formed in the housing, through which a working fluid is supplied to the low pressure portion of the pump unit; a low pressure chamber which is communicated with the suction passage and the low pressure portion; and a discharge passage through which the working fluid pressurized by the pump unit is discharged, wherein when the pump unit is accommodated in the pump unit receiving portion, the low pressure chamber is formed between the pump unit and a wall surface of the housing which defines the pump unit receiving portion, and the discharge passage is formed by a communication pipe which extends through the low pressure chamber and communicates the housing and the high pressure portion of the pump unit with each other, wherein the pump unit is a tandem gear pump comprising two gear pumps, the pump unit comprising a drive shaft which drives drive gears of the gear pumps, wherein the gear pumps are arranged along an axial direction of the drive shaft, wherein the two gear pumps are coaxially coupled to each other, the low pressure chamber is divided into a first low pressure chamber corresponding to one of the two gear pumps and a second low pressure chamber corresponding to the other of the two gear pumps by O-rings, and the communication pipe is disposed in each of the first and second low pressure chambers.