Title:
HYDRAULIC CONTROL CIRCUIT FOR A CONSTRUCTION MACHINE
Document Type and Number:
WIPO Patent Application WO/2020/119947
Kind Code:
A3
Abstract:
[Problem to Be Solved] To make it possible to control supply, discharge, and recycled flow rates independently of each other for the stick cylinder in a construction machine comprising first and second stick spool valves respectively connected to first and second hydraulic pumps. [Solution] A poppet valve (20) is provided at upstream side of the first stick spool valve (18) for controlling a supply flow rate from first hydraulic pump (11), the first stick spool valve is configured to supply hydraulic flow from the poppet valve to the stick cylinder (9) without restricting the flow, and when the stick cylinder is extended, the poppet valve is configured to control supply flow rate from the first hydraulic pump to head side oil chamber, the first stick spool valve is configured to control recycled flow rate from a rod side oil chamber to the head side oil chamber, and the second stick spool valve is configured to control the supply flow rate from second hydraulic pump (12) to head side oil chamber and the discharge flow rate from the rod side oil chamber to an oil tank (15).
Inventors:
NAKAJIMA HIDEKI (JP)
KIYASU KOICHI (JP)
KIYASU KOICHI (JP)
Application Number:
PCT/EP2019/025453
Publication Date:
July 23, 2020
Filing Date:
December 11, 2019
Export Citation:
Assignee:
CATERPILLAR SARL (CH)
International Classes:
E02F9/22
Domestic Patent References:
| WO2000055509A1 | 2000-09-21 | |||
| WO2010026678A1 | 2010-03-11 |
Foreign References:
| EP0104613A2 | 1984-04-04 |
Attorney, Agent or Firm:
BRP RENAUD & PARTNER MBB (DE)
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