1. Flow control
The oil discharge of the pump can be arbitrarily controlled according to the pilot pressure P
(1) Flow reduction
After the pilot pressure P increases, the pilot piston moves to the right and stops at a position where the pilot spring force and hydraulic pressure are balanced. The pin fixed on the rod 2 is inserted into the groove part of the pilot piston. With the movement of the pilot piston, the rod 2 rotates with the B part (fulcrum cock and pin fixed) as the fulcrum. The pin fixed on the feedback lever 2 protrudes from the large hole of the lever 2 (C position), and the pin moves to the right.
The pin fixed on the rotating pin used to move the swash plate is embedded in the two wide surfaces of the feedback lever (D part), so as the pin (897) moves, the feedback lever rotates with the D part as the fulcrum. Since the spool valve is connected to the feedback lever by a pin, the spool valve moves to the right.
After the spool valve moves, the oil discharge pressure P mountain is introduced into the large bore chamber of the servo piston through the spool valve and the Cl oil port. The oil discharge pressure is introduced into the small bore chamber of the servo piston at any time. As a result, the servo piston moves to the right due to the difference in the area of the large and small bore chambers. After the flow servo piston moves to the right, the D part also moves to the right. A return spring is installed on the spool valve, and the spring force pulls the spool valve to the left at any time, so the pin is pushed to the large hole part (C part) of rod 2. Therefore, with the movement of part D, the feedback lever rotates with part C as the fulcrum, and the spool valve moves to the left. Through this movement, the openings of the sleeve and the slide valve begin to slowly close, and the servo piston stops moving at the position where the openings are completely closed.
(2) Increase in flow
After the pilot pressure P is reduced, the pilot piston is moved to the left by the force of the pilot spring, and the rod 2 rotates with the B part as the fulcrum. The pin is pressed into the large hole (C part) of rod 2 by the return spring through the spool valve, pin and feedback rod. Therefore, with the rotation of rod 2, the feedback rod rotates with part D as the fulcrum, and the spool valve moves to the left. After the valve moves, the CI oil port opens to the oil tank oil port, the pressure in the large bore chamber of the servo piston is emptied, and the oil discharge pressure Pa at the small bore part moves the servo piston to the left, so that the flow increases as the servo piston moves. , The D part also moves to the left, the feedback lever rotates with the C part as the fulcrum, the spool valve moves to the right, and the servo piston will keep moving until the spool valve and the opening of the sleeve are completely closed.
(3) High voltage selection function
The pilot pressure P is used as a flow control signal, which can be imported from multiple command pressures through the shuttle valve auxiliary valve. The selected KR3G9Y04IVV selects high pressure from P1 and the secondary pressure of the proportional valve, while KR3G9X04HV selects high pressure from P2 and external command pressure P2. Choose high pressure
1, output power control
The output power control is shown in Figure 3-38. After the load pressure increases, the tilt angle of the pump decreases, so as to avoid the prime mover from overloading. The regulator is a synchronous full output power control method, and the tilt angle (working volume) of the two pumps is controlled by the same value.
The operation of output power control is the same as that of flow control, so a brief description will be given below.
(1) Prevent overload operation
When the discharge pressure Pa1 of the self pump or the discharge pressure P of the other pump rises, since Pt and Pa act on the stepped part of the compensation piston, the compensation connecting rod is pushed to the right and moved to the spring of the outer spring and the inner spring. A position where force and hydraulic pressure are balanced. The movement of the compensating link is transmitted to the rod 1 through the pin, and the rod 1 rotates around the pin (part E) fixed on the housing. The pin fixed on the feedback lever protrudes from the large hole part (F part) of the rod 1. With the rotation of the rod 1, the feedback rod rotates with the D part as the fulcrum, so that the slide valve moves to the right.
After the spool valve moves, the oil discharge pressure Pa1 is introduced into the large bore part of the servo piston through the CI port, and the servo piston moves to the right to reduce the oil displacement of the pump and prevent the prime mover from overloading the movement of the servo piston. When it is transmitted to the feedback lever, the feedback lever rotates with the F part as the fulcrum, and the spool valve moves to the left. The servo piston will keep moving until the spool valve and the opening of the sleeve are completely closed and will stop moving
(2) Automatic flow recovery
After the discharge pressure P4 of the self-pump or the discharge pressure Pa2 of the counterforce pump is reduced, the outer spring and the inner spring push the compensating link back to its original position, and the rod 1 rotates around the E part. As the lever 1 rotates, the feedback lever rotates with part D as the fulcrum, and the slide valve moves to the left. Therefore, the CI oil port opens to the oil tank oil port, the pressure in the large bore chamber of the servo piston is emptied, the servo piston moves to the left, and the oil discharge flow of the pump increases the rotation of the servo piston, which is transmitted to the spool valve through the feedback mechanism. The spool valve and the opening of the sleeve continue to rotate before they are completely closed.
3, low tilt rotation (low flow) command priority structure
As mentioned above, the tilt rotation command for flow control and output power control is transmitted to the feedback lever and the spool valve through the large holes (C, F) of lever 1 and lever 2, but because the φ5 pin protrudes from C, F Because of the structure on the large hole (9 in the middle) of the part, the pin only contacts the rod that can make the tilt smaller, and does not contact the 9-hole of the rod on the side that is in the larger tilt command state. According to this mechanical selection method, the commands on the low-incline side of flow control and output power control can be given priority.
4, power switching control (control to reduce output power)
The set output power of the pump can be arbitrarily controlled according to the power switching pressure P.
After the power switching pressure P increases, the compensation connecting rod is moved to the right by the pin and the compensation piston. Therefore, the same as the above description of preventing the output power overload operation, the inclination angle of the pump can be reduced, thereby reducing the output power setting value. Conversely, if the power switching pressure P decreases, the output power value will increase.
