HYDRAULIC CLOSED CIRCUIT SYSTEM - HITACHI CONSTRUCTION MACHINERY

Title:

HYDRAULIC CLOSED CIRCUIT SYSTEM

Document Type and Number:

WIPO Patent Application WO/2013/175866

Kind Code:

A1

Abstract:

With respect to a hydraulic closed circuit system that uses multiple hydraulic pumps, the objective of the present invention is to adjust the flow volume automatically and thus to enable the flow volume balance to be maintained in a satisfactory state, even when the flow volume is not balanced during the expansion/contraction of a hydraulic cylinder device due to pump capacity error and the like. A first hydraulic pump (12) is connected to a hydraulic cylinder device (11) so as to form a hydraulic closed circuit, one of a pair of discharge ports of a second hydraulic pump (13) is connected to the bottom side of the hydraulic cylinder device (11) and the other is connected to a tank (16), the first and second hydraulic pumps (12, 13) are driven by a motor (20), and power is recovered. A pump capacity control device (100) detects the direction of operation and the low-thrust-side pressure of the hydraulic cylinder device (11) and controls the capacity of the second hydraulic pump (13) such that the flow volume during expansion/contraction of the hydraulic cylinder device is balanced between the first and second hydraulic pumps and the hydraulic cylinder device.

Inventors:

UDAGAWA TSUTOMU (JP)
TANAKA HIROAKI (JP)

Application Number:

PCT/JP2013/059687

Publication Date:

November 28, 2013

Filing Date:

March 29, 2013

Export Citation:

Click for automatic bibliography generation Help

Assignee:

HITACHI CONSTRUCTION MACHINERY (JP)

International Classes:

F15B11/08; E02F9/22; F15B11/00

Foreign References:

JP2009079775A	2009-04-16
JP2006336842A	2006-12-14
JP2006194325A	2006-07-27
JP4733645B2	2011-07-27
JPS6396303A	1988-04-27
JP2002054602A	2002-02-20

Other References: