Patent ID: 8926299
Filing Date: 2015-01-06
Classification: F04C

Abstract:
1. A pump device, comprising: a housing; a pump section, a discharge volume of which is configured to be increased and reduced, and which includes a drive gear unit that is immobile in an axial direction and a driven gear unit that is movable in the axial direction; a main flow channel through which oil pressure is applied to said driven gear unit in a discharge volume reduction direction; a first branching flow channel through which oil pressure is applied to the driven gear unit in the discharge volume reduction direction, in addition to the oil pressure from the main flow channel; a second branching flow channel through which oil pressure is applied to said driven gear unit in a discharge volume increase direction; a first flow channel control section that is provided in the first branching flow channel and performs flow channel control of communication or shut-off of the first branching flow channel by a solenoid valve; a second flow channel control section that is provided in the second branching flow channel and performs flow rate control of communication or shut-off of the second branching flow channel by a spool valve; and a spring that elastically urges said driven gear unit in the discharge volume increase direction, wherein the driven gear unit comprises a valve piston including a main pressure-receiving surface that receives the oil pressure from the main flow channel and an auxiliary pressure-receiving surface that receives the oil pressure from the first branching flow channel, and an axial-direction end portion of the driven gear unit on a side opposite to the valve piston across the driven gear includes a return pressure-receiving surface that receives oil pressure from the second branching flow channel, and wherein said first flow channel control section and said second flow channel control section perform control so as to switch between communication and shut-off between said first branching flow channel and said second branching flow channel in accordance with an increase or a decrease in engine revolutions and an increase or a decrease in pressure.