Bosch Rexorth Gear pump PGM4-4X/050RT11VU2 R901374266 Rexroth

Set-up
Hydraulic pumps of type PGM-4X are gap-compensated internal gear pumps with constant displacement. They basically comprise of: Mounting flange (1), housing (2), cover (3), pinion shaft (4), internal gear (5), plain bearings (6), axial washers (7) and stop pin (8), as well as the radial compensation consisting of segment (9), segment support (10) and the seal rolls (11).
Suction and displacement procedure
The hydrodynamically mounted pinion shaft (4) drives the internally geared internal gear (5) in the direction of rotation shown. The tooth clearances opening in the suction range suck in the hydraulic fluids. The hydraulic fluid is transported into the tooth clearances of pinion and internal gear, from the suction range (S) into the pressure range (P). There, the hydraulic fluid is displaced from the closing tooth clearances and delivered into the pressure port (P).
Suction and pressure range are separated by the radial compensation elements (9 to 11) and the tooth engagement between internal gear and pinion shaft.
Axial compensation
The displacement area in the pressure range is axially sealed by axial washers (7). To the sides of the axial washers facing away from the displacement area a pressure field (12) is applied. These fields balance the axial washers vis-à-vis the displacement area, which results in a perfect sealing with low mechanical losses.
Radial compensation
The radial compensation elements consist of segment (9), segment support (10) and seal rolls (11). Segment (9) and segment support (10) are arranged in the pressure field so that the resulting compressive force is basically accepted by the stop pin. A small compressive force component presses segment and segment support onto the tooth tips of pinion shaft and internal gear and in this way provides for the sealing of the pressure range to the suction range with automatic clearance adjustment. This is the prerequisite for constantly high volumetric efficiency during the entire operating time.
The clearance adjustment of segment and segment support is made possible by the seal rolls located inbetween.
Hydrodynamic and hydrostatic mounting
The pinion shaft (4) is accepted by hydrodynamically lubricated radial plain bearings (6). The internal gear (5) is mounted hydrostatically in the housing.
Gear tooth system
The gear tooth system with involute edges has a large meshing length for little flow and pressure pulsation and thus guarantees low-noise running.
Materials used
Flange (1) and cover (3): cast iron
Housing (2) and lateral washers (7): aluminum
Shaft (4) and internal gear (5): steel
Hydraulic pumps of type PGM-4X are gap-compensated internal gear pumps with fixed displacement.

• Frame size 4, 5
• Size 25 … 125
• Component series 4X
• Maximum operating pressure 210 bar
• Maximum displacement 125.3 cm³