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. 30, 2019
Filed:
Feb. 22, 2016
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Hiroaki Amano, Kasumigaura, JP;
Kouji Ishikawa, Kasumigaura, JP;
Shinya Imura, Toride, JP;
Hidekazu Moriki, Mito, JP;
Ryohei Yamashita, Tsuchiura, JP;
Seiji Hijikata, Tsukuba, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Disclosed is a hydraulic drive system capable of improving the fuel efficiency of a work machine by reducing the pressure loss and drag loss of a hydraulic pump. There are provided an electric motor M; a third pump Pdriven by the electric motor; a third pump hydraulic line Lto which the delivered hydraulic fluid from the third pump is supplied; a third directional control valve Vprovided in the third pump hydraulic line, switch-operated by an arm operation device, and controlling the flow rate of the hydraulic fluid supplied to the arm cylinderfrom the third hydraulic pump; and a controllerdrive-controlling the electric motor, wherein the controller drives the third pump by the electric motor when a swing/arm combined operation is detected by pilot pressure sensors S, S, S, S