The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 30, 2007
Filed:
Jun. 19, 2003
Tetsuya Goto, Kariya, JP;
Takeharu Matsuzaki, Kariya, JP;
Shigeto Nakajima, Nagano-ken, JP;
Yasuhiro Maeda, Nagano-ken, JP;
Keinosuke Ichikawa, Nagano-ken, JP;
Tetsuya Goto, Kariya, JP;
Takeharu Matsuzaki, Kariya, JP;
Shigeto Nakajima, Nagano-ken, JP;
Yasuhiro Maeda, Nagano-ken, JP;
Keinosuke Ichikawa, Nagano-ken, JP;
Kabushiki Kaisha Toyota Jidoshokki, Kariya-shi, JP;
Nishina Industrial Co. Ltd., Kamiminochi-gun, Nagano-ken, JP;
Abstract
A main spool is located in a bypass line connecting a pump line to a return line. The main spool moves in an axial direction according to the pressure in a spring chamber and the pressure in a pilot chamber, thereby adjusting the opening degree of the bypass line. A pilot switching valve is located in a pressure control passage connecting the spring chamber to the return line. The pilot switching valve controls the flow rate of hydraulic oil that flows from the spring chamber to the return line in accordance with the load pressure of a hydraulic actuator, thereby adjusting the pressure of hydraulic oil in the spring chamber. As a result, the range of the flow rate of hydraulic oil supplied to the hydraulic actuator, which range precludes the influence of the load pressure of the hydraulic actuator, is expanded.