●Speed control loop: Because the hydraulic system has low power and has a positive load, the oil inlet throttle speed control loop is selected. For good low speed smoothness and speed load characteristics, speed governor valve speed can be selected and back pressure can be set on the hydraulic cylinder circuit.
●Pump oil supply circuit: Because the difference between the working speed and the fast moving speed is very different, the double pump is used for oil supply.
●Speed switching circuit and fast circuit: Because the difference between the working speed and the fast forward speed is very different, in order to make the switching smooth, the switching circuit controlled by the stroke valve is selected. Fast motion is achieved by a differential circuit.
●Commutation circuit: For smoothness, use electro-hydraulic directional control valve. In order to achieve the neutral stop and differential connection of the hydraulic cylinder, a three-position five-way valve is used.
●Pressure control circuit: The use of the reversing valve type low-voltage load circuit reduces energy consumption and the structure is relatively simple.
2. Hydraulic Circuit Selection
Adjustments, modifications and merging are necessary for the synthesis of the selected basic loop.
●To prevent the intake and return lines from being drilled during work feed, and to access the check valve.
To achieve differential fast forward, a hydraulic control sequence valve must be installed on the return line to prevent oil from flowing back to the tank.
The working principle of the complete hydraulic system after the merger is as follows: