Title:
HYDRAULIC DRIVE DEVICE FOR CONSTRUCTION MACHINE
Document Type and Number:
WIPO Patent Application WO/2019/186841
Kind Code:
A1
Abstract:
In the present invention, even when differential pressures before and after direction switching valves associated with respective actuators are extremely low, flow rate control of a hydraulic pump and diversion control of a plurality of direction switching valves can be performed stably, and even when requested flow rates are suddenly changed during transition from a composite operation to a single operation, and the like, the flow rates of pressure oil supplied to the respective actuators can be prevented from suddenly changing to thereby realize excellent composite operability, and meter-in losses of the direction switching valves are reduced to realize high energy efficiency. For these purposes, the downstream sides of a plurality of direction switching valves 6a, 6b, 6c are respectively provided with a plurality of pressure compensation valves 7a, 7b, 7c for performing control such that the pressures on the downstream sides of meter-in openings of the direction switching valves 6a, 6b, 6c are equal to the respective maximum load pressures, requested flow rates of the direction switching valves 6a, 6b, 6c are calculated from input amounts of operation levers, a meter-in pressure loss of a predetermined direction switching valve is calculated from the requested flow rates of the direction switching valves 6a, 6b, 6c and from meter-in opening areas, and a set pressure of an unload valve 15 is controlled by using the values having been calculated.
Inventors:
TAKAHASHI KIWAMU (JP)
MAEHARA TAIHEI (JP)
ISHII TAKESHI (JP)
MAEHARA TAIHEI (JP)
ISHII TAKESHI (JP)
Application Number:
PCT/JP2018/013015
Publication Date:
October 03, 2019
Filing Date:
March 28, 2018
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD (JP)
International Classes:
F15B11/05; E02F9/22
Domestic Patent References:
| WO2014084213A1 | 2014-06-05 |
Foreign References:
| JPH05187411A | 1993-07-27 | |||
| JPH11315805A | 1999-11-16 | |||
| JP2015105675A | 2015-06-08 | |||
| JP2007506921A | 2007-03-22 | |||
| JP2014098487A | 2014-05-29 |
Other References:
See also references of EP 3591239A4
Attorney, Agent or Firm:
KAICHI IP (JP)
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