| 摘要 |
A variable displacement pump includes: a discharge opening formed at a position to confront a discharge region; a back pressure introduction groove formed on the suction region side; and a discharge side thin wall portion which is formed in the second housing, which has a recessed shape opened to the outside, which is disposed on the discharge region side, which is overlapped with the rotor in the radial direction, and which includes a smallest thickness portion having a smallest wall thickness of thicknesses each of which is an axial length between a bottom surface of the recessed shape and an axially inner side surface of the second housing, the smallest wall thickness being a smallest wall thickness of axial thicknesses of the second housing. |
| 主权项 |
1. A variable displacement pump comprising:
a pump housing including a first housing including a cylindrical portion, and a bottom portion closing one axial side of the cylindrical portion, and a second housing closing the other axial side of the cylindrical portion; a drive shaft rotatably supported by the pump housing; an annular cam ring movably provided within the cylindrical portion of the first housing; a rotor provided within the cam ring, and driven and rotated by the drive shaft; a plurality of slits formed in the rotor in a circumferential direction; a plurality of vanes each of which is provided within one of the slits to be moved into and out of the one of the slits, and which separate a plurality of pump chambers with the cam ring and the rotor; a pressure plate provided within the cylindrical portion of the first housing between the bottom portion of the first housing and the cam ring, and pressed toward the cam ring by a discharge pressure discharged from the pump chambers; a suction opening formed in the second housing, and formed at a position to confront a suction region in which volumes of the plurality of pump chambers are increased in accordance with the rotation of the rotor; a suction passage formed in the second housing, and arranged to introduce a hydraulic fluid from an outside of the pump housing to the suction opening; a discharge opening formed in one of the pressure plate and the second housing, and formed at a position to confront a discharge region in which the volumes of the plurality of the pump chambers are decreased in accordance with the rotation of the rotor; a discharge passage formed in the pump housing, and arranged to discharge a discharge hydraulic fluid which is the hydraulic fluid discharged from the discharge region, to the outside of the pump housing; a back pressure introduction groove which is formed in the second housing, which has an arc shape to confront base end portions of the slits that are radially innermost ends of the slits, which is formed at least on the suction region side, and which is arranged to protrude the vanes in the radially outside direction by receiving a part of the discharge hydraulic fluid; and a discharge side thin wall portion which is formed in the second housing, which has a recessed shape opened to the outside, which is disposed on the discharge region side, which is overlapped with the rotor in the radial direction, and which includes a smallest thickness portion having a smallest wall thickness of thicknesses each of which is an axial length between a bottom surface of the recessed shape and an axially inner side surface of the second housing, the smallest wall thickness being a smallest wall thickness of axial thicknesses of the second housing. |
