Rexroth oil pump from Germany

The German REXROTH pump includes various types of pumps, such as vane pumps and plunger pumps, each with different working principles:

Working principle of German REXROTH vane pump

Single acting vane pump: composed of rotor, stator, blades, oil distribution plate, and end cover and other components. The inner surface of the stator is a cylindrical hole, and there is eccentricity between the rotor and the stator. The blades can slide flexibly in the slots of the rotor. Under the centrifugal force during rotor rotation and the pressure oil flowing into the root of the blades, the top of the blades is tightly attached to the inner surface of the stator, forming sealed working chambers between two adjacent blades, oil distribution plate, stator, and rotor. When the rotor rotates counterclockwise, the blades on the right side of the figure extend outward, and the volume of the sealed working chamber gradually increases, creating a vacuum. Therefore, oil is sucked in through the suction port and the window on the oil distribution plate. On the left side of the figure, the blades retract inward, and the volume of the sealing chamber gradually decreases. The oil in the sealing chamber is squeezed out through another window of the oil distribution plate and the pressure port and output into the system. This type of pump is called a single acting pump because it absorbs oil and pressurizes oil once during each rotation of the rotor.

Double acting vane pump: Its operating principle is similar to that of a single acting vane pump, with the only difference being that the stator surface is composed of eight parts: two long radius arcs, two short radius arcs, and four transition curves, and the stator and rotor are concentric. When the rotor rotates clockwise in the diagram, the volume of the sealed working chamber gradually increases at the upper left and lower right corners, which are the oil suction area, and gradually decreases at the lower left and upper right corners, which are the oil pressure area; There is a sealing area between the oil absorption area and the oil pressure area to separate them. This type of pump is called a double acting vane pump because each sealed working chamber completes two oil suction and pressure actions for each rotation of the rotor.

Working principle of REXROTH plunger pump in Germany

Radial piston pump: mainly composed of stator, rotor, oil distribution shaft, liner, and plunger. There are several radially arranged holes evenly distributed on the rotor, and the plunger can slide freely in the holes. The oil distribution shaft divides the inner hole of the liner into upper and lower oil separation chambers, which are respectively connected to the suction and pressure ports of the pump through the axial holes on the oil distribution shaft. The stator and rotor are installed eccentrically. When the plunger moves to the upper half of the cycle, the stator presses the plunger into the plunger hole, and the sealing volume of the plunger hole decreases. The oil in the hole is pressed into the system through the oil chamber and the oil discharge port, which is the oil pressure process. Every time the rotor rotates, each plunger sucks and presses oil once.

Axial piston pump: There are two structural forms of axial piston pumps: straight shaft type (inclined disc type) and inclined shaft type (swing cylinder type). The characteristics of axial piston pumps are compact structure, small radial size, low inertia, and high volumetric efficiency. Currently, the highest pressure can reach 40MPa or even higher, and they are generally used in high-pressure systems such as construction machinery and presses. But its axial size is large, the axial force is also large, and the structure is relatively complex. The working process of the REXROTH plunger pump in Germany is as follows: the transmission shaft drives the cylinder body to rotate, and there are odd numbered plunger holes evenly distributed on the cylinder body. The plunger holes are equipped with plungers, and the head of the plunger is tightly pressed against the inclined plate through the sliding shoe. When the cylinder body rotates, one side of the plunger rotates with the cylinder body, and due to the fixed action of the inclined plate, the plunger performs reciprocating motion in the hole. When the cylinder body rotates upward from the bottom position shown in the diagram, the plunger extends outward, and the sealing volume of the plunger hole increases, forming a local vacuum. The oil in the tank is sucked into the plunger hole, which is the oil suction process; When the cylinder body drives the plunger to rotate downwards from the top position shown in the diagram, the plunger is pressed into the plunger hole, the sealing volume inside the plunger hole decreases, and the oil in the hole is squeezed out. This is the oil pressure process. Every time the cylinder rotates, each plunger hole completes the process of oil suction and pressure.

The above is an introduction to the working principle of the German REXROTH pump. It should be noted that in practical applications, attention should also be paid to the maintenance and management points of the pump to ensure its long-term stable operation.