Title:
HYDRAULIC DRIVE SYSTEM FOR CONSTRUCTION MACHINERY
Document Type and Number:
WIPO Patent Application WO/2019/224879
Kind Code:
A1
Abstract:
This hydraulic drive system for construction machinery is provided with: a swing motor; a swing operation device that outputs a swing operation signal according to the inclination angle of an operation lever; a swing direction switching valve that includes a spool and a drive unit which receives a command current and drives the spool, and that increases the supply amount of a working fluid to the swing motor and the discharge amount of the working fluid from the swing motor as the command current increases; a control device that supplies, to the swing direction switching valve, a command current that increases as the swing operation signal increases; and a pressure sensor that detects the outflow pressure of the swing motor. When the swing operation signal has decreased, the control device supplies a command current to the swing direction switching valve when the outflow pressure of the swing motor as detected by the pressure sensor increases past a threshold, thereby maintaining the movement speed of a spool at or below a limit value.
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Inventors:
MURAOKA HIDEYASU
NOSE TOMOMICHI
KINOSHITA NOBUYUKI
OKASHIRO TAKASHI
SAKAMOTO MORIYUKI
NOSE TOMOMICHI
KINOSHITA NOBUYUKI
OKASHIRO TAKASHI
SAKAMOTO MORIYUKI
Application Number:
PCT/JP2018/019516
Publication Date:
November 28, 2019
Filing Date:
May 21, 2018
Export Citation:
Assignee:
KAWASAKI HEAVY IND LTD (JP)
International Classes:
F15B11/00; E02F9/22
Foreign References:
| JPH08199631A | 1996-08-06 | |||
| JPH06330902A | 1994-11-29 | |||
| JP2013234683A | 2013-11-21 | |||
| JPH10299703A | 1998-11-10 | |||
| JPH08333778A | 1996-12-17 |
Attorney, Agent or Firm:
PATENT CORPORATE BODY ARCO PATENT OFFICE (JP)
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