| 摘要 |
Disclosed is a hydraulic circuit for controlling operation oil, which is supplied from a hydraulic pump to a hydraulic cylinder, and operation oil, which is returned from the hydraulic cylinder to an operation oil tank. The present invention provides a hydraulic circuit for a construction machine, characterized by comprising: a hydraulic pump and a pilot pump; a hydraulic cylinder driven by operation oil from the hydraulic pump; an electrically manipulated level; a first control valve installed in a channel between the hydraulic pump and the hydraulic cylinder so as to supply, when switching, operation oil from the hydraulic pump to a first chamber of the hydraulic cylinder or to return operation oil, which is discharged from the first chamber of the hydraulic cylinder, to an operation oil tank; a second control valve installed in a channel between the hydraulic pump and the hydraulic cylinder so as to return, when switching simultaneously with the first control valve, operation oil, which is discharged from a second chamber of the hydraulic cylinder, to the operation oil tank or to supply operation oil from the hydraulic pump to the second chamber of the hydraulic cylinder; and proportional control valves installed in a channel between the pilot pump and the first control valve and in a channel between the pilot pump and the second control valve, respectively, such that, in order to independently control the spool opening area of the first and second control valves, a pilot pressure corresponding to the amount of manipulation of the electronically manipulated level is applied to the first and second control valves, thereby switching the same. |
