What are the functions of the piston of the pump truck

Secondary piston: In the state of electronic control, the secondary oil flow of the pilot controls the secondary piston independently. The negative flow does not participate in direct control, but the pressure parameter is collected by the negative pressure sensor and provided to the computer, which is calculated by the computer as the control electric ratio A parameter of the valve current is used to control the secondary oil flow of the pilot; in the hydraulic control state, the secondary oil flow of the pilot is cut off by the hydraulic-to-electronic control valve, and does not participate in the control of the secondary piston, and the secondary piston is independently controlled by the negative flow. direct control. The working direction of the secondary piston is to push the spool of the slide valve to move to the left, which is balanced by the return of its own spring.

Primary piston: It is controlled by the oil flow of the front pump, the oil flow of the rear pump and the primary oil flow of the pilot (only in the hydraulic control state). Its working direction is to push the slide valve core to move to the left, and it is returned by its own spring. constitute a balance.

The actuator is a variable piston:

The variable piston is composed of a fixed piston sleeve and a plunger with different cross-sectional areas at both ends. The plunger is connected with the swash plate and the slide valve sleeve. When the pressure difference is generated on the two end faces, the plunger drives the other two together. sports.