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:
Aug. 28, 2018
Filed:
Nov. 26, 2014
Hitachi Construction Machinery Tierra Co., Ltd., Tokyo, JP;
Kiwamu Takahashi, Moriyama, JP;
Yasutaka Tsuruga, Ryuugasaki, JP;
Kazushige Mori, Moriyama, JP;
Yoshifumi Takebayashi, Kouka, JP;
Natsuki Nakamura, Kouka, JP;
Yasuharu Okazaki, Namerikawa, JP;
Kenji Yamada, Toyama, JP;
Hitachi Construction Machinery Tierra Co., Ltd., Koka-shi, JP;
Abstract
The object is to make it possible to efficiently utilize rated output torque of the prime mover by performing total torque control with high precision through precise detection of absorption torque of the other hydraulic pump by use of a purely hydraulic structure and feedback of the absorption torque to the one hydraulic pump's side. For this purpose, the hydraulic drive system is equipped with: a torque feedback circuitwhich is supplied with delivery pressure of a main pumpand load sensing drive pressure, modifies the delivery pressure of the main pumpto achieve a characteristic simulating the absorption torque of the main pump, and outputs the modified pressure; and a torque feedback pistonwhich is supplied with output pressure of the torque feedback circuit and controls displacement of a main pumpso as to decrease the displacement of the main pumpand thereby decrease maximum torque Tas the output pressure increases. The torque feedback circuitincludes first and second variable pressure reducing valvesand