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1. (WO2017154438) VARIABLE DISPLACEMENT PUMP

Pub. No.:    WO/2017/154438    International Application No.:    PCT/JP2017/004185
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Tue Feb 07 00:59:59 CET 2017
IPC: F04C 2/344
F04C 14/00
F04C 15/00
Applicants: HITACHI AUTOMOTIVE SYSTEMS, LTD.
日立オートモティブシステムズ株式会社
Inventors: SAGA, Koji
佐賀 浩二
OHNISHI, Hideaki
大西 秀明
WATANABE, Yasushi
渡辺 靖
Title: VARIABLE DISPLACEMENT PUMP
Abstract:
Provided is a variable displacement pump comprising: a first control oil chamber 21 for applying force by internal oil pressure, to a cam ring 5 in the direction in which the amount of change in the volume of pump chambers 13 is reduced; a second control oil chamber 22 for applying force by internal oil pressure, to the cam ring in the direction in which the amount of change in the volume of the pump chambers is increased; first seal surfaces 44 formed on both end surfaces of the cam ring 5, which slide on the facing inner surfaces of a pump body 1 and a cover member 2, and sealing between the pump chambers and the first control oil chamber; and second seal surfaces 45 which, within a discharge-side region, seal between the pump chambers and the second control oil chamber. The radial width W2 of the second seal surfaces is configured to be greater than the radial width W1 of the first seal surfaces. As a result, an unintended increase in pump control pressure is prevented and an increase in the weight of the entire pump is prevented.