Patent ID: 7905711

Claim:
A multiple pump unit comprising: a pump shaft operatively connected to a driving power source; a first pump driven by the pump shaft; a pump housing for accommodating the first pump; a second pump operatively driven by the pump shaft; a fluid passage block connected to one end surface in an axis line direction of the pump housing; a third pump arranged on a side opposite to the first pump in the axis line of the pump shaft with the second pump as a reference, the third pump being operatively driven by the pump shaft; and a third pump housing connected to an outer surface of the fluid passage block so as to surround the third pump, wherein one or both contacting surfaces of the pump housing and the fluid passage block is/are formed with a concave portion for accommodating the second pump, wherein the pump housing is provided with a suction fluid passage having a first end opened to an outer surface to form a suction port, the suction fluid passage guiding hydraulic fluid, which has been introduced through the suction port, to a suction opening of the first pump, and a first pump discharge fluid passage having a proximal end fluidly connected to a discharge opening of the first pump and a distal end opened to an outer surface to form a first pump discharge port, wherein the fluid passage block is provided with a second pump discharge port having the second pump as a hydraulic source, wherein the suction fluid passage is configured to guide operation fluid, which has been sucked through the suction port, to a first suction opening of the second pump on a side close to the first pump as well as to the suction opening of the first pump, wherein the suction fluid passage includes a third pump branched fluid passage for guiding hydraulic fluid, which has been introduced through the suction port, to a contacting surface with the fluid passage block, wherein the third pump housing is provided with a third pump suction fluid passage having a first end opened to a contacting surface with the fluid passage block and a second end fluidly connected to a suction opening of the third pump, and a third pump discharge fluid passage having a first end fluidly connected to a discharge opening of the third pump and a second end opened to an outer surface to form a third pump discharge port, and wherein the fluid passage block is formed with a communication passage; said communication passage fluidly connects the third pump branched fluid passage to the third pump suction fluid passage, and to a second suction opening of the second pump; said second suction opening being disposed on a side opposite to the first suction opening of the second pump in reference to the axis line of the pump shaft.