VARIABLE DISPLACEMENT PUMP

摘要

PROBLEM TO BE SOLVED: To ensure flying-out of a vane along with rotation of a rotor, to prevent the occurrence of shortage in a feed amount of fluid to a vane base end part during high speed rotation of a variable displacement pump and the excessive rise of a fluid temperature, and to ensure startability of the pump. SOLUTION: This pump comprises a rotor 15 to hold a plurality of vanes 15a radially movably forward and backward; and an oscillating cam ring 17 having a pump chamber 18 formed closer to one side of the rotor. An opening 25 on the suction side opened to the region on the suction side of a pump chamber and an opening 24 on the discharge side opened to the region on the discharge side thereof are formed in the side wall part 20 on the front side and on the rear side of a pump body. An arcuate groove 63 corresponding to the region on the suction side of the pump chamber and an arcuate groove 64 on the discharge side corresponding to the region on the discharge side thereof are formed in a portion around the rotary shaft 16 of the rotor at the side wall part of the pump body and positioned the rotation locus of the base end part 62 of the holding groove 61 of the rotor to hold the vane. Communication holes 65 and 66 formed in the pump body and running from the pressure chamber on the discharge side of a fluid pressure on the pump discharge side discharged from the pump chamber formed in a pump body are opened to the respective arcuate grooves.