Title:
AXIAL PISTON DOUBLE-TYPE HYDRAULIC PUMP
Document Type and Number:
Japanese Patent JP3189921
Kind Code:
B2
Abstract:
PURPOSE: To seal even a narrow and abutting surface with an ordinary O-ring, and to prevent an oil leakage in a casing as well as to improve the extent of service life in this O-ring.
CONSTITUTION: A stepped ring groove 32A consisting of a deep inner groove 32A adjoining to the inner circumferential side of a casing body and a shallow outer ring groove 32B adjoining to the outer circumferential side of the inner ring groove 32A is integrally formed on an abutting surface 31A of this casing body. In addition, an almost elliptically cylindrical backup ring 33 is installed in the inner ring groove 32A, and an O-ring 34 is installed on the outer circumferential side of this backup ring 33 so as to be energized in the diametral expanding direction from the inside. Since the O-ring 34 is installed in the outer ring groove 32B to be partitioned off by the backup ring 33, at the time of operation of a hydraulic pump, such a possibility that this O-ring 34 might come into contact with pressure oil of a high temperature or be damaged after receiving a variation in the pressure oil or otherwise is thus preventable from occurring.
Inventors:
Tetsuya Sakairi
Goto Yasuharu
Kazumasa Yuasa
Shigetaka Nakamura
Yukihiro Motozawa
Cao Donghui
Goto Yasuharu
Kazumasa Yuasa
Shigetaka Nakamura
Yukihiro Motozawa
Cao Donghui
Application Number:
JP14146193A
Publication Date:
July 16, 2001
Filing Date:
May 20, 1993
Export Citation:
Assignee:
Hitachi Construction Machinery Co., Ltd.
International Classes:
F04B1/20; F04B1/24; F04B53/00; (IPC1-7): F04B1/20; F04B1/24; F04B53/00
Domestic Patent References:
| JP61205380A | ||||
| JP5569165U | ||||
| JP626482U | ||||
| JP5892547U | ||||
| JP51067U | ||||
| JP3107008U |
Attorney, Agent or Firm:
Kazuhiko Hirose