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:
Nov. 23, 2004
Filed:
Oct. 07, 2002
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Fault diagnosis of hydraulic pumps is made automatically during an actual operation of a working machine, particularly when there is a problem with horsepower limiting control of the hydraulic pumps. A controller performs horsepower limiting control for a plurality of variable displacement hydraulic pumps to . The controller measures a pump delivery pressure and pump delivery rate of each hydraulic pump when the pump delivery rate reaches a maximum during operation of the hydraulic drive system based on their detected values, collects the measured values as fault diagnostic data, and then compares a calculated target pump delivery rate with the collected pump delivery rate to decide if there is a fault of the hydraulic pump.