Hydraulic system of the laser screed
The hydraulic system comprises a hydraulic oil tank, variable pump, main valve, auxiliary valve, hydraulic oil cooler, motor, cylinder and pipeline, hydraulic oil tank on the rear frame and the fuel tank placed side by side, the main valve and the auxiliary valve are respectively arranged at the rear part and the front part of the front frame, the variable pump is located under the main valve plate at the rear of the front frame.
2.The main pump
The main pump is a load sensitive variable pump, which is driven directly by the power output device of the engine, and is connected with the coupling of the pump bracket and the coupling, the oil from the tank passes through the main pump to the multi-way valve.
The main components of the main pump includes pump shell, pilot piston, valve plate, plunger spring, plunger, return disc, sliding boots, swash plate, Spindle, spline sleeve, pump body and seal, etc., the principle of work: The swash plate axial piston pump transfers the rotation of the input shaft to the axial reciprocating motion of the plunger, in the first half period of rotation from the plunger removed in cylinder plunger hole, at the same time, the volume of the working cavity is enlarged, Into the cylinder plunger hole in the second half period of plunger rotation, the volume of the cavity decreases at the same time. The reciprocating movement takes the liquid into the exhaust.
The reciprocating motion is caused by the angle between the swash plate and the axis of the drive shaft (Variable pump).
The displacement of the pump is controlled by the control valve, which determines the pressure in the pilot piston. When the pilot pressure increases, the swashplate angle decreases, resulting in the decrease of plunger stroke and the decrease of pump displacement, the transmission pressure and the spring pressure of the pump work together on the balance plunger to keep the pump at the maximum displacement.