The inclined axis axial piston pump usually consists of main components such as a cylinder block, a distribution board, a plunger and a swash plate. There are multiple plungers in the tank body, and the plungers are arranged axially. That is to say, the center line of the plunger is parallel to the transmission shaft, so it is also called a wet plunger pump.

Inclined axis piston pump classification:

There are two main forms of inclined-axis axial piston pumps: double-hinge pumps and hingeless pumps.

1.Double hinge pump

The double-hinge pump uses two unidirectional hinges connected in series to drive the cylinder to rotate. When the spindle disk at the end of the transmission shaft rotates, the plunger cylinder is driven to rotate through the bidirectional hinge. At the same time, the spindle disk drives the plunger to reciprocate through the connecting rod, and absorbs and discharges oil through the oil distribution plate.

When the double hinges of the double-hinge pump drive the cylinder to rotate, they are only used to overcome the friction torque between the cylinder and the oil distribution plate. The effective torque is achieved by the force on the connecting rod. Due to the complex structure of double-hinge pumps and the high requirements for manufacturing and processing precision, there are currently very few production and applications. On the basis of the double-hinge pump, a hingeless pump was designed and manufactured.

2. Hingeless pump

The cylinder of the hingeless pump is supported in the housing through a central pin. One end of the connecting rod is hinged with the main shaft disk at the end of the transmission shaft, and the ball head at the other end is installed in the plunger. When the transmission shaft rotates, the side surface of the connecting rod contacts the inner wall of the plunger and drives the cylinder to rotate through the plunger. At the same time, the plunger reciprocates in the plunger hole of the cylinder to absorb and discharge oil through the oil distribution plate.

Inclined axis piston pump structure:

The oblique axis axial piston pump is composed of a transmission main shaft 1, a connecting rod 2, a plunger 3, a cylinder 4, a central shaft 5, a spherical distribution plate 6, a shell and a back cover. The cylinder body and the axis of the transmission main shaft are relatively at an inclination angle γ, and the drive plate 7 at the end of the shaft is connected to each plunger in the cylinder body with a universal hinge and connecting rod. When the prime mover drives the main shaft of the pump to rotate, the connecting rod and plunger pair alternately "toggle" the cylinder to slide and rotate on the distribution plate with a waist-shaped window.

Since there is an angle between the spindle and the axis of the cylinder, the plunger obtains an oil suction stroke when it moves from the bottom dead center to the top dead center, and the oil is sucked into the cylinder through the oil suction port and the waist-shaped window of the valve plate. When the plunger moves from top dead center to bottom dead center, a pressure stroke occurs, and the oil filled in the cylinder hole is discharged through the valve plate and the oil outlet. Viewed from the direction of the drive shaft, if the pump rotates clockwise (right turn), the suction port is on the left side of the back cover, and the pressure port is on the right side of the back cover. Still looking from the direction of the drive shaft, if the drive shaft rotates counterclockwise (turn left), the oil suction port is on the right side of the rear cover, and the pressure port is on the left side of the rear cover.

Working principle of inclined axis piston pump:

When the inclined axis piston pump motor rotates the transmission shaft, the pump cylinder and the plunger rotate together, and the plunger head is always in contact with the swash plate. As the swash plate moves from 0 to 180, that is, the plunger, the volume of the plunger cylinder gradually increases, and the liquid is sucked into the oil barrel through the air inlet A of the oil drain plate. When the plunger changes from 180 to 360, the volume of the plunger cylinder gradually decreases, and the liquid in the cylinder is discharged through the outlet of the oil drain plate. As long as the drive shaft of the inclined axis axial piston pump continues to rotate, the pump will continue to operate. By changing the angle of the tilting element, the moving length of the plunger in the pump cylinder can be changed, thereby changing the pump flow rate. The one with a fixed tilt angle is called a fixed pump, and the one that can change the tilt angle is called a variable pump.

The difference between inclined axis piston pump and swash plate plunger pump:

1. The plunger in the oblique axis piston pump is driven by the connecting rod, and the radial force is very small, so the angle between the transmission shaft and the cylinder axis is allowed to reach 25°, and has reached 40°, so the pump has a larger displacement. The inclination angle of the swash plate axial piston pump is bound by the radial force and generally does not exceed 20°.

2. The overturning moment experienced by the oblique axis piston pump cylinder is very small, the end face of the cylinder and the oil distribution plate fit evenly, the leakage loss is small, the volumetric efficiency is high; the friction loss is small, and the mechanical efficiency is high.

3. Compact structure and good impact resistance.

4. Because the transmission shaft of the inclined axis pump has to withstand considerable axial and radial forces, thrust bearings with large load-bearing capacity need to be selected.

5. The total power of the inclined axis pump is slightly higher than that of the swash plate pump. However, the inclined axis pump is large in size, and the flow adjustment is accomplished by shaking the cylinder to change the angle between the cylinder axis and the transmission axis. The inertia of the moving parts is large and the dynamic response is slow.

6. Since the hinge can be better anchored, which is beneficial to the return stroke of the plunger, the inclined axis piston pump is allowed to operate under self-priming conditions or lower inlet pressure, and its self-priming performance is better than the inclined plate axial piston pump.