Patent ID: 11168684

Abstract:
Variable displacement pump has first control hydraulic chamber 21 giving force to cam ring 5 in direction that decreases volume variation of each pump chamber 13 by internal pressure, second control hydraulic chamber 22 giving force to cam ring in direction that increases volume variation of each pump chamber by internal pressure, first seal surface 44 formed on both end surfaces of cam ring, which are in sliding-contact with both opposing inside surfaces of pump body 1 and cover member 2, and sealing gap between each pump chamber and first control hydraulic chamber, and second seal surface 45 sealing gap between each pump chamber and second control hydraulic chamber at outlet section side. Radial direction width W2 of second seal surface is greater than that W1 of first seal surface. Increase in weight of the pump can be suppressed while suppressing increase in pump control pressure against intention of control.