Bosch Rexorth Gear pump PGP2-2X/006RN20VM R900962904 Rexroth

Design
PGP hydraulic pumps are leak-gap-compensated internal gear pumps with a fixed displacement.
They consist basically of: housing (1), bearing cover (1.1), cover (1.2), ring gear (2), pinion shaft (3), slide bearings (4), axial discs (5) and stop pin (6) as well as the segment assembly (7) which is composed of a segment (7.1), segment carrier (7.2) and the sealing rolls (7.3).
Suction and displacement process
The hydrodynamically supported pinion shaft (3) drives the internally toothed ring gear (2) in the direction of rotation shown.
During rotation, the volume is increased in the suction area over an angle of approx. 180°. A negative pressure is generated and fluid flows into the chambers.
The sickle-shaped segment assembly (7) separates the suction chamber from the pressure chamber. Within the pressure chamber, the teeth of the pinion shaft (3) mesh with the tooth spaces of the ring gear (2). The fluid is then displaced through the pressure channel (P).
Axial compensation
The axial compensation force FA acts in the area of the pressure chamber and is generated by the pressure zone (8) in the axial discs (5). The axial, longitudinal gaps between rotating and fixed parts are therefore extremely small and ensure optimum axial sealing of the pressure chamber.
Radial compensation
The radial compensation force FR acts on the segment (7.1) and segment carrier (7.2).
The area ratios and the position of the sealing rolls (7.3) between the segment and segment carrier are designed to provide virtually gap-free sealing between the ring gear (2), the segment assembly (7) and the pinion shaft (3).
Spring elements under the sealing rolls (7.3) ensure adequate contact pressure, even at very low pressures.
Hydrodynamic and hydrostatic bearing
The forces acting on the pinion shaft (3) are absorbed by hydrodynamically lubricated radial slide bearings (4) while those acting on the ring gear (2) are absorbed by the hydrostatic bearing (9).
Splines
Involute splining was selected for the gear. Their long length of contact results in a low flow and pressure pulsation; these low pulsation rates contribute greatly to the low-noise operation.
Used materials
Housing (1), bearing cover (1.1), cover (1.2) and axial discs (5): Steel-aluminum compound material
Ring gear (2), pinion shaft (3) and stop pin (6): Steel
Slide bearing (4): Copper-tin with steel back
Segment (7.1) and segment carrier (7.2): Brass alloy
Sealing rolls (7.3): Plastic

• Fixed displacement
• Frame size 2, 3
• Size 6.3 … 32
• Maximum pressure 350 bar
• Displacement 6.5 … 32.5 cm³