Working Principle And Performance Characteristics Of Axial Piston Pump
Axial piston pumps are generally composed of main components such as cylinder body, oil distribution plate, plunger, and inclined plate. There are multiple plungers in the cylinder body, and the plungers are arranged axially, that is, the center line of the plunger is parallel to the axis of the transmission shaft, so it is called an axial plunger pump. But it is different from reciprocating piston pumps because its plunger not only performs reciprocating motion inside the pump cylinder, but also rotates relative to the inclined plate between the plunger and the pump cylinder. The plunger contacts the inclined plate with a spherical end. There are high and low pressure moon shaped grooves on the oil distribution plate, which are separated by partition walls to ensure a certain degree of sealing. They are respectively connected to the inlet and outlet of the pump. There is a tilt angle between the axis of the inclined plate and the axis of the cylinder block.
The working principle of axial piston pump is that when the electric motor drives the transmission shaft to rotate, the pump cylinder and plunger rotate together, and the plunger head always maintains contact with the inclined plate. Because the inclined plate forms an angle with the cylinder body, when the cylinder body rotates, the plunger performs reciprocating motion in the pump cylinder. Taking a plunger as an example, when it rotates from 0 ° to 180 °, i.e. to the position of the upper plunger, the volume of the plunger cylinder gradually increases, so the liquid is sucked into the cylinder through the oil suction port a of the distribution plate; When the plunger rotates from 180 ° to 360 °, the volume of the plunger cylinder gradually decreases, so the liquid in the cylinder is discharged through the outlet of the oil distribution plate. As long as the drive shaft continues to rotate, the pump will continue to work.
By changing the angle of the tilting element, the stroke length of the plunger in the pump cylinder can be altered, thereby changing the flow rate of the pump. A fixed tilt angle is called a quantitative pump, while a variable tilt angle that can be changed is called a variable pump.
There are two types of axial piston pumps based on the different tilting elements: inclined disc type and inclined shaft type.
The inclined disc is a cylinder body with a tilted angle relative to the rotation of the inclined disc, which causes the plunger to reciprocate in the pump cylinder. The axis of the transmission shaft and the axis of the cylinder block are consistent. This structure is relatively simple and has a high rotational speed, but it requires high working conditions, and the contact between the plunger end and the inclined plate is often a weak link. The axis of the inclined disc of the inclined shaft type is consistent with the axis of the transmission shaft. It is caused by the plunger cylinder tilting at an angle relative to the transmission shaft, causing the plunger to reciprocate. Flow regulation relies on the angle of the swinging plunger cylinder body to achieve, so some are also known as swing cylinder type. Compared with the inclined disc type, it works reliably and has a large flow rate, but its structure is complex.
Axial piston pumps are generally used in hydraulic transmission systems of machine tools, metallurgy, forging, mining, and lifting machinery, and are particularly widely used in high-power hydraulic transmission systems. In order to improve efficiency, gear pumps or slide pumps are usually used as auxiliary oil pumps in applications to supply oil, compensate for leaks, and maintain a certain pressure in the oil circuit.
