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. 05, 2013
Hitachi Construction Machinery Co., Ltd., Bunkyo-ku, Tokyo, JP;
Tsutomu Udagawa, Tsukuba, JP;
Akira Nakayama, Tsuchiura, JP;
Ryohei Yamashita, Tsuchiura, JP;
Shiho Izumi, Hitachinaka, JP;
Manabu Edamura, Kasumigaura, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hidetoshi Satake, Ishioka, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controllerincludes a target pump pressure setting unitwhich calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detectorA/B based on the operation amount signal and a pump flow rate upper limit setting unitwhich calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal. The tilt amount of the hydraulic pumpis controlled based on the target pump delivery pressure calculated by the target pump pressure setting unit, the pump flow rate upper limit calculated by the pump flow rate upper limit setting unit, and the delivery pressure of the hydraulic pumpdetected by a pressure detector