1) Structure understanding and the role of each component
2) Working principle of swash plate axial piston pump
The cylinder block is connected with the spline on the main shaft, so that it rotates together with the main shaft. The plunger assembly is installed inside the cylinder that moves with the swash plate. The plunger moves from the bottom dead center to the top dead center and moves in the direction of increasing outlet flow. After the hydraulic oil passes through the suction port, it flows to the cylinder through the valve plate (suction process). During the stroke from the top dead center to the bottom dead center, the plunger always moves in the direction of decreasing oil discharge, and the hydraulic oil is discharged through the oil discharge port. (Draining process). The oil displacement varies with the inclination angle of the swash plate. The hydraulic oil sucked in through the cylinder body suction port is discharged through the oil discharge port of the valve plate, while the hydraulic oil sucked in through the oil suction port of the cylinder body (inner) ring is discharged through the oil discharge port of the outer (inner) ring of the valve plate.
3) Port plate
Function: Separate the oil suction area (low pressure area) and oil discharge area (high pressure area), and form a sealed volume with the cylinder and plunger.
4) Pump control function
Pump is a variable displacement plunger pump that discharges two identical flow rates from one cylinder. Although it has a double pump structure, the 3 pump and the pilot pump are connected on the same axis through a coupling sleeve, but its structure is very compact. Because this pump has only one swash plate, the inclination angle is the same. The tilt angle of the pump can change the total flow Q1+Q2. The output power is a constant value, so the product of the outlet pressure and the flow rate is constant, that is, (Q1+Q2)X p=P(constant).
Pump control function
The angle of the swash plate is determined by the discharge pressure of the PI pump and the P2 pump, and the force of the power spring is opposite to the direction of the discharge pressure. When the pressure is less than the set load of the power bomb A, the swash plate is at the position of the maximum inclination angle. When the pressure exceeds the set load of the power spring A, the inclination angle of the swash plate will change to a small angle, and.
Fixed at a position in a balanced state under the hydraulic oil pressure and the force of the power spring A. When the inclination angle of the swash plate continues to decrease due to the increase of the hydraulic oil pressure, the spring B that has not worked until it starts to work. If the elastic force of the two spring forces is to be overcome, the highest bottom dead center of the oil pressure must be reached. . When the p3 hydraulic oil that pushes the servo piston flows in, the control displacement curve will be changed.
