Axial piston pump working principle and performance characteristics
Axial piston pumps are generally composed of main components such as cylinders, oil distribution plates, plungers and swashplates. There are a plurality of plungers in the cylinder, and the plungers are axially aligned, that is, the center line of the plunger is parallel to the axis of the drive shaft, so it is called an axial piston pump. However, it is different from the reciprocating plunger pump because its plunger not only reciprocates in the pump cylinder, but also the plunger and the pump cylinder rotate relative to the swash plate. The plunger is in contact with the swash plate with a spherical end. There are high and low pressure moon-shaped grooves on the oil distribution plate, which are separated from each other by a partition wall to ensure a certain sealing property, which are respectively connected with the oil inlet and the oil outlet of the pump. There is an oblique angle between the axis of the swash plate and the axis of the cylinder.
The working principle of the axial piston pump, when the motor drives the transmission shaft to rotate, the pump cylinder rotates together with the plunger, and the plunger head always keeps in contact with the swash plate, because the swash plate is at an angle with the cylinder body, so when the cylinder body rotates, The plunger reciprocates in the pump cylinder. Taking a plunger as an example, it is turned from 0° to 180°, that is, it is turned to the position of the upper plunger, and the volume of the plunger cylinder is gradually increased, so that the liquid sucks the oil cylinder through the oil suction port a of the oil distribution plate; When the plug is turned from 180° to 360°, the volume of the plunger cylinder is gradually reduced, so that the liquid in the cylinder discharges the liquid through the outlet of the oil distribution tray. As long as the drive shaft rotates continuously, 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 changed to change the flow rate of the pump. A fixed angle pump is called a fixed pump, and the tilt angle can be changed as a variable pump.
The axial piston pump has two types of swash plate type and oblique axis type depending on the tilting element.
The swash plate type has an inclined angle with respect to the rotating cylinder, and causes the plunger to reciprocate in the pump cylinder. The drive shaft axis and the cylinder axis are identical. This structure is simpler, the rotational speed is higher, but the working conditions are high, and the contact portion between the end of the plunger and the swash plate is often a weak link. The axis of the swash plate of the oblique axis is identical to the axis of the drive shaft. It is because the plunger cylinder is tilted at an angle relative to the drive shaft to cause the plunger to reciprocate. The flow adjustment is realized by the angle of the swing plunger cylinder, so some are also called the swing cylinder type. Compared with the swash plate type, it works reliably and has a large flow, but the structure is complicated.
Axial piston pumps are commonly used in hydraulic transmission systems for machine tools, metallurgy, forging, mining and hoisting machinery, and are particularly widely used in high-power hydraulic transmission systems. In order to improve efficiency, a gear pump or a vane pump is usually used as an auxiliary oil pump in the application to supply oil, make up for leakage and maintain a certain pressure in the oil path.