Hydraulic drive system for construction machine

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 9890518
SERIAL NO

14431062

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ATTORNEY / AGENT: (SPONSORED)

Importance

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Abstract

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During boom-midair lowering operation in which a front work implement 130 can be turned under the self-weight of a boom 131, a hydraulic pump/motor 7 is operated as a motor to operate a generator/electric motor 10 as a generator. Power generation operation is performed by the hydraulic fluid discharged from a bottom-side chamber 5b of a boom cylinder 5 to recover positional energy. During jack-up in which the front work implement 130 cannot be turned under the self-weight of the boom 131, the generator/electric motor 10 is operated as an electric motor to operate the hydraulic pump/motor 7 as a pump. The jack-up is performed by supplying the hydraulic fluid from the bottom-side chamber 5b to rod-side chamber 5a of the boom cylinder 5 without supplying the hydraulic fluid from the main pump 2 to the rod-side chamber 5a of the boom cylinder 5.

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First Claim

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Patent Owner(s)

Patent OwnerAddress
HITACHI CONSTRUCTION MACHINERY CO LTDTOKYO 110-0015

International Classification(s)

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Ishikawa, Kouji Kasumigaura, JP 152 903
Nakamura, Tsuyoshi Tsuchiura, JP 229 1506
Sato, Kensuke Ushiku, JP 35 230

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