The main body (see the structural section) drives the cylinder to rotate by the transmission shaft, so that the seven plungers evenly distributed on the cylinder rotate around the centerline of the transmission shaft, and the slide shoes in the column slide assembly are pressed against the variable head ( Or swash plate). In this way, the plunger reciprocates with the rotation of the cylinder to complete the oil suction and oil pressure actions.
BCY14-1B type electro-hydraulic proportional control variable pump is designed using the principle of "flow-displacement-force feedback". It is a new variable type in CY14-1B axial piston pump and is external The oil pressure is controlled to control the variable mechanism, and the current of the input proportional solenoid is used to change the flow of the pump. The input current is proportional to the flow of the pump. The pump has flexible control, sensitive action, high repeat accuracy and good stability, and can easily realize remote control, automatic control, stepless speed regulation, tracking feedback synchronization and computer control of the hydraulic system, which is suitable for the requirements of industrial automation.
The manufacturer of the oil pump motor unit stated that the working principle of the electro-hydraulic proportional control variable pump is shown in the right figure. When the input current of the proportional electromagnet 1 is zero, the pilot valve core 3 is pushed to the upper end by the action of the feedback spring 6. The external control oil enters the upper and lower chambers of the variable piston 7, because the upper cavity area A 'is larger than the lower cavity area A, the variable piston is pushed down, the deflection angle of the variable head 8 is zero, and the pump displacement is also zero. When the input current becomes larger, the pilot valve core 3 moves downwards under the push of electromagnetic force, thereby opening the upper valve port of the pilot valve, and the upper cavity of the variable piston 7 is connected to the oil return cavity through the control edge, and the pressure of the upper cavity is reduced. The variable piston moves upward, the variable head deflection angle increases, and the displacement of the pump also increases. At the same time, the displacement of the variable piston acts on the pilot spool through a compression feedback spring, pushing the pilot spool to the equilibrium position, and the variable piston That is, at a certain equilibrium position, the displacement of the pump is also maintained at a certain value. Conversely, when the input current is reduced, the pilot spool moves upward under the action of the feedback spring, so that the valve opening to the oil return chamber is reduced, and the valve opening into the upper chamber is increased, thereby increasing the upper chamber pressure Pc ' The variable piston moves downward until the electromagnetic force equals the feedback spring force, and the pilot spool returns to the equilibrium position, so that Pc '· A' = Pc · A, and the variable piston is balanced at a new position.
When the input current does not change, if the variable piston moves up or down due to load or other reasons, the displacement change of the variable piston will act on the pilot spool through the feedback spring to change the opening of the pilot valve to make the variable piston The pressure of the upper chamber of the pump is increased or decreased to resist the change of the load force, and the variable piston is returned to the position corresponding to the input current, that is, the displacement is maintained.
It can be seen that the proportional variable pump can achieve proportional control of the displacement under the action of the input current without being disturbed by the load.
The main performance indicators of BCY14-1B variable pump are: hysteresis H1 <5%, repeatability HR <3%, nonlinearity HLI <5%, resolution HΔ1 <2%, frequency response f-3dB≥1.5MHz (160 , 250BCY pump), f-3dB≥3MHz (25, 63BCY pump).