| 摘要 |
PURPOSE: An oil-hydraulic circuit for construction machinery which can control a flow rate of work fluid is provided to improve operation convenience and reliability by making the operation of the work equipment or running gear stop without operating a safety lever. CONSTITUTION: An oil-hydraulic circuit for construction machinery comprises first and second hydraulic pumps(P1,P2), a pilot pump, first work equipment, a left side driving motor(8), second work equipment, a right side driving motor(9) and a proportional pressure control valve(10). The first and second work equipment is operated by the control valve switched by the pilot pressure provided from a pilot pump according to the manipulation of first and second operation levers for the work equipment, respectively. The left and right side driving motors are operated by the control valve switched by the pilot pressure provided from a pilot pump according to the manipulation of a driving operation lever(3). The proportional pressure control valve outputs the pilot pressure comparing with to the electrical control signal inputted from the controller and supplies the pilot pressure to the first and second operation levers and driving operation lever. |
