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. 06, 2020
Filed:
Mar. 27, 2017
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Provided is a work machine hydraulic control system capable of detecting abnormality in a pump output power switching device independently of the abnormality state of the pump output power switching device. A hydraulic control system of a hydraulic excavator is equipped with an accumulatorconnected to a hydraulic lineA between a pilot pumpand a pilot valve, an unloading valvethat is a pump output power switching device, a pressure sensordetecting the pressure of the hydraulic fluid supplied to the pilot valve, and a controllerhaving a pump output power control sectionswitching the unloading valvein accordance with the pressure detected by the pressure sensor. The controllerfurther has an abnormality determination sectionthat computes a command continuation time in a state in which a command output to the unloading valveis not changed. In the case where this command continuation time is not less than a predetermined value, it determines that the unloading valveis abnormal, and outputs the determination result.