Hydraulic circuit for construction equipment

Abstract

A hydraulic circuit for construction equipment is disclosed, which can prevent an abrupt rotation of a swing device when a switching valve (7,8) for the swing device is shifted in a state that switching valves (3,4,1,2,5,6) for a traveling device and a working device have been shifted. The hydraulic circuit includes first to fourth hydraulic pumps (P 1 ,P 2 ,P 3 ,P 4 ); first to six (1-6) switching valves installed in the first to second hydraulic pumps, respectively, and shifted to control hydraulic fluid fed to working devices or traveling devices; a confluence switching valve (9) installed in the third hydraulic pump (P 3 ) and shifted to supply the hydraulic fluid to the working devices (1,2,5,6) on the first (P 1 ) and second (P 2 ) hydraulic pump sides; signal lines (15,16) for the traveling devices and the working devices; a first valve (21) connected between the signal line (15) for the traveling device and an intersection between the signal line (17) for the confluence switching valve (9) and a tank line (18); and a second valve (22) installed in a flow path (17a) between the first valve (21) and the tank line (18), shifted to discharge pressure in the signal line (17) for the confluence switching valve (9) to the tank line (18) or to block the flow path (17a) to form the signal pressure in the signal line (17) for the confluence (9).

Description

[0001] Cross references to related applications [0002] This application is based on and claims the priority of Korean patent application 10-2007-0031465 filed at the Korean Intellectual Property Office on March 30, 2007, and the entire content of this earlier application is incorporated herein by reference. Technical field [0003] The present invention relates to a hydraulic circuit for construction equipment. When switching valves used for walking devices and working devices such as booms and robotic arms in a hydraulic system using multiple hydraulic pumps, the hydraulic circuit can switch the hydraulic The fluid is supplied from the hydraulic pump to the work device through the confluence switch valve. [0004] More specifically, the present invention relates to a hydraulic circuit for construction equipment. When the on-off valve for the corresponding working device is switched to the state where the confluence on-off valve has been switched, that is, the on-off valve for the ...

AI Technical Summary

Problems solved by technology

[0017] Therefore, in the case of switching the third on-off valves 7 and 8 connected to the third hydraulic pump P3, working devices such as a swing device, a selection device, etc. sudden movement), thereby reducing the maneuverability and safety of the working device

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