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:
Jul. 18, 2006
Filed:
Feb. 18, 2002
Nobuei Ariga, Niihari-gun, JP;
Genroku Sugiyama, Ryugasaki, JP;
Hideaki Tanaka, Tsuchiura, JP;
Tsukasa Toyooka, Higashiibaraki-gun, JP;
Masaki Egashira, Niihari-gun, JP;
Takatoshi Ooki, Niihari-gun, JP;
Nobuei Ariga, Niihari-gun, JP;
Genroku Sugiyama, Ryugasaki, JP;
Hideaki Tanaka, Tsuchiura, JP;
Tsukasa Toyooka, Higashiibaraki-gun, JP;
Masaki Egashira, Niihari-gun, JP;
Takatoshi Ooki, Niihari-gun, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
To keep one of three hydraulic pumps unaffected by variations in torque of the remaining hydraulic pumps when the three hydraulic pumps are used, displacements of the first and second hydraulic pumps are controlled based on their own delivery pressures P, Pand a pressure P' obtained by reducing through a reducing valvea delivery pressure Pfrom the third hydraulic pump, while a displacement of the third hydraulic pumpis controlled only by its own delivery pressure P. The pressure oil delivered from the third hydraulic pump, therefore, remains unaffected by variations in delivery flow rates from the first and second hydraulic pumps, in other words, by variations in their torque consumptions, so that the third hydraulic pump is assured to provide a stable flow rate.