Vane pump

Abstract

A vane pump includes a cam ring, a rotor, a plurality of vane, and a lateral plate. The lateral plate has an extension groove. The shape of a pump chamber forming surface viewed from the rotation-axis direction of the rotor satisfies the following requirements i) and ii) at the time when a first vane passes the base end part of the extension groove: i) the center line of the groove width of the extension groove is inclined from the radial direction of the rotor; and ii) a slit in which a second vane is accommodated has an open end falling within a belt-shaped range obtained by extending a groove width of the base end part of the extension groove along a virtual extension line.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to Japanese Patent Application No. 2020-171460 filed on Oct. 9, 2020, incorporated herein by reference in its entirety.BACKGROUND1. Technical Field[0002]The present disclosure relates to a vane pump.2. Description of Related Art[0003]A vane pump configured to discharge, from a discharge port, oil taken into an inlet port by a rotor rotating inside a rotor chamber is used for operation of a transmission or the like of a vehicle, for example. The rotor is configured such that vanes are accommodated in respective slits formed in a radial manner. In such a vane pump, when minute air bubbles included in the oil crush flatly due to an increase in pressure in an oil discharge step, erosion (cavitation damage) is caused by impact of the crush. In view of this, various measures to this erosion have been proposed.[0004]In a vane pump described in Japanese Unexamined Patent Application Publication No. 2019-210881 (JP ...

AI Technical Summary

Benefits of technology

The present patent provides a vane pump that can prevent erosion more effectively. This means that the pump can reduce the damage caused by the pump's operation.

Problems solved by technology

In such a vane pump, when minute air bubbles included in the oil crush flatly due to an increase in pressure in an oil discharge step, erosion (cavitation damage) is caused by impact of the crush.

Further, in the vane pump described in JP 2018-123818 A, when the back pressure to be introduced into the pump chamber from the plate-side pressurization groove and the rotor-side pressurization groove is raised, such a problem might be caused that the pressure in the back-pressure groove decreases and the back pressure to push out the vane from the slit becomes insufficient.

On this account, these measures might not necessarily yield a sufficient effect to restrain erosion depending on the specification such as a required discharge pressure, a required discharge amount, or the like.

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