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:
Jun. 09, 2020
Filed:
Dec. 14, 2017
Hitachi Construction Machinery Tierra Co., Ltd., Koka-shi, Shiga, JP;
Kiwamu Takahashi, Moriyama, JP;
Taihei Maehara, Koka, JP;
Kazushige Mori, Moriyama, JP;
Yoshifumi Takebayashi, Koka, JP;
Natsuki Nakamura, Koka, JP;
Hibachi Construction Machinery Tierra Co., Ltd., Koka-shi, JP;
Abstract
In a hydraulic drive system of a work machine which drives a plurality of actuators using three or more pumps, for an operation not including traveling, a highly efficient combined operation in a front implement and excellent combined operability of a swing and the front implement are enabled, while for an operation including traveling, a highly efficient traveling operation and a highly efficient combined operation of traveling and the front implement are enabled, and a sufficient operation speed of the front implement is achieved. To this end, each of the flow rates of the first, second, and third pumps () can be controlled independently by performing the load sensing control, and in a combined operation for driving a boom () and an arm (), ether one of them is driven by the first pump while the other one is driven by the second pump, and the swing is driven by the third pump. In the traveling operation, the maximum capacity of the first and second pumps is switched to the maximum capacity for the traveling operation and driven by an open center circuit. In a combined operation of traveling and the front implement, the front implement is driven by performing the load sensing control using the third pump.