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. 02, 2020
Filed:
Jan. 31, 2018
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Masamichi Ito, Ibaraki, JP;
Takatoshi Ooki, Ibaraki, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
There is provided a hydraulic driving device for working machine having operability handling a change in burden weight in a front working device due to a loaded burden and the like when the working machine that accumulates energy in an accumulator and recovers and regenerates the energy performs an operation of lowering the front working device. A hydraulic driving deviceincludes a main pump, a boom cylinder, a tank, a flow rate control valve, an accumulator, a first differential pressure control valve, and a second differential pressure control valve. The first differential pressure control valveis located between the boom cylinderand the accumulator. The first differential pressure control valveperforms control on discharge oil from the boom cylindersuch that a differential pressure between before and after the flow rate control valvebecomes a target differential pressure. The second differential pressure control valveis located between the accumulatorand the tank. The second differential pressure control valveperforms control on the discharge oil such that a differential pressure between an upstream pressure and a downstream pressure of the flow rate control valveand the first differential pressure control valvebecomes the target differential pressure. The first and the second differential pressure control valvesandare configured such that the target differential pressure increases according to an increase in pressure of the discharge oil.