REXROTH

PGH4-3X/050RE11VU2 Bosch Rexroth Internal Gear Pump

The Bosch Rexroth PGH4-3X/050RE11VU2 is a high-pressure internal gear pump with constant displacement for industrial and mobile hydraulic applications. Identified by material number R901147104, this pump belongs to the Bosch Rexroth PGH-3X family and uses a gap-compensated internal gear design to provide efficient hydraulic flow with low operating noise and low flow pulsation.

The pump has nominal size 50 with a geometric displacement of 50.7 cm³ per revolution. Current Bosch Rexroth product data specifies a maximum operating pressure of 280 bar and a maximum volume flow of 150 l/min. The configuration uses clockwise rotation, a cylindrical Ø25 mm keyed shaft according to ISO 3019-2, a two-hole mounting flange 101-2 according to ISO 3019-1, FKM seals, and a through-drive for flexible integration into hydraulic pump combinations.

Key Features and Product Configuration

• Bosch Rexroth high-pressure internal gear pump
• Material number: R901147104
• Product family: PGH
• Frame size: 4
• Component series: 3X, series 30 to 39
• Constant displacement design
• Nominal size: 50
• Geometric displacement: 50.7 cm³/rev
• Maximum operating pressure: 280 bar
• Maximum volume flow: 150 l/min
• Maximum operating pressure with special fluids: 175 bar
• Clockwise rotation when viewed from the drive shaft
• Cylindrical Ø25 mm shaft with fitting key
• Shaft according to ISO 3019-2
• Two-hole mounting flange 101-2 according to ISO 3019-1
• Through-drive included
• FKM shaft seal and FKM seals
• Suitable for multiple approved hydraulic fluids
• Unpacked weight: 17.56 kg
• Gap-compensated internal gear construction
• Suitable for variable-speed hydraulic drive concepts

Technical Specifications

Gap-Compensated Internal Gear Pump Design

Bosch Rexroth PGH pumps use an internal gear principle in which a pinion shaft drives an internally geared ring gear. As the gears rotate, the opening tooth spaces on the suction side draw hydraulic fluid into the pump. The fluid is transported through the tooth spaces toward the pressure side and displaced into the hydraulic circuit as the gear teeth engage again.

The suction and pressure areas are separated by the gear engagement and radial compensation elements. This gap-compensation principle automatically adapts internal sealing clearances to the operating pressure. The design helps reduce internal leakage and supports high volumetric efficiency throughout the service life of the pump.

Low Noise and Low Flow Pulsation

One of the important advantages of the PGH internal gear design is low hydraulic noise. The internal gear geometry provides a relatively long tooth engagement, which contributes to smooth fluid displacement and low flow pulsation. This can be beneficial in industrial machinery where hydraulic noise, pressure fluctuations, and vibration should be minimized.

The combination of radial gap compensation, axial sealing, hydrodynamically lubricated bearings, and internal gear geometry also supports reliable operation across a wide range of hydraulic operating conditions. These characteristics make the pump suitable for modern hydraulic systems where efficiency and stable flow delivery are important.

Hydraulic Performance

The nominal size 50 configuration has a geometric displacement of 50.7 cm³/rev. Bosch Rexroth currently specifies a maximum volume flow of 150 l/min for material number R901147104. The maximum operating pressure currently listed for this specific product is 280 bar.

These figures are maximum product ratings rather than automatic continuous operating conditions for every machine. The actual operating point should be determined according to hydraulic-system pressure, required flow, drive speed, fluid temperature, viscosity, inlet conditions, duty cycle, and the ratings of the other components installed in the system.

For special hydraulic fluids, Bosch Rexroth lists a lower maximum operating pressure of 175 bar for this specific configuration. The hydraulic fluid and sealing system must therefore be considered together during system design and product replacement.

Shaft, Rotation and Mounting Configuration

The R designation identifies clockwise rotation when viewed from the drive-shaft side. Rotation direction is critical when replacing an internal gear pump because the suction and pressure functions depend on the specified direction of rotation.

The E shaft configuration uses a cylindrical Ø25 mm drive shaft with a fitting key according to ISO 3019-2. The U2 mounting configuration uses a two-hole mounting flange 101-2 according to ISO 3019-1. These standardized mechanical interfaces simplify installation when the motor, coupling, bell housing, and hydraulic equipment use the corresponding dimensions.

The complete mechanical configuration should nevertheless be checked before replacement. Two PGH pumps with the same nominal size can use different shaft ends, rotation directions, mounting arrangements, line connections, or seal configurations.

Through-Drive and Pump Combination Capability

This configuration is supplied with a through-drive. Bosch Rexroth PGH-3X pumps are designed so that different internal gear pump sizes can be combined, and approved combinations can also be created with other compatible Bosch Rexroth pump types.

Through-drive capability is useful when multiple hydraulic circuits must be supplied from one mechanical drive. It allows another compatible pump stage to be mechanically driven behind the front pump, reducing the need for additional motors or separate drive arrangements.

Pump combinations require careful engineering. Maximum drive torque, pressure, shaft loading, rotational speed, and the permissible combination components must be checked using the relevant Bosch Rexroth technical documentation before installation.

Hydraulic Fluids and FKM Seals

Bosch Rexroth lists this product with FKM shaft sealing and FKM internal seals. Compatible hydraulic-fluid families listed on the current product information include HLP, HLPD, HVLP, HVLPD, HETG, HEES, HEPG, HFDU, and HFDR.

Fluid compatibility does not mean that every listed fluid can be used with identical pressure, temperature, or speed limits. Special fluids can require reduced operating values. The current product data, for example, lists a maximum operating pressure of 175 bar for special fluids.

Hydraulic-fluid viscosity, temperature, filtration, and cleanliness are especially important for precision gear pumps. Clean hydraulic fluid helps protect the internal gear teeth, plain bearings, axial sealing surfaces, and radial compensation components from premature wear.

Industrial Applications

The pump is suitable for hydraulic systems that require high efficiency, low noise, low pulsation, and dependable fixed-displacement flow. Typical applications include plastics-processing machinery, automated presses, casting machinery, machine tools, hydraulic power units, forming equipment, production machinery, accumulator charging systems, and variable-speed hydraulic drive systems.

The low moment of inertia and efficient internal gear design also make PGH pumps useful in applications with frequent load changes. Final suitability must always be determined from the pressure and flow profile, drive system, hydraulic fluid, required duty cycle, and complete system design.

Selection and Replacement Guidance

When replacing R901147104, verify the complete model rather than selecting a pump only by nominal size. The full designation identifies a specific combination of frame size 4, series 3X, size 50, clockwise rotation, cylindrical keyed shaft, hydraulic connection arrangement, FKM seals, and two-hole mounting flange.

The material number should also be compared directly with the original pump nameplate. Similar PGH4 pumps may have different displacement sizes, shafts, mounting flanges, port configurations, rotation directions, seals, or pressure ratings even when their external appearance is similar.

For another Bosch Rexroth PGH internal gear pump configuration, see the Bosch Rexroth PGH4-30/063RE11VU2 internal gear pump. Additional hydraulic pumps, valves, motors, and industrial replacement components are available through Hydraulics Worldwide for international sourcing and supply support.

Official Bosch Rexroth Product Reference

For current manufacturer specifications, CAD information, documentation, and product data, visit the official Bosch Rexroth product page for R901147104. The Bosch Rexroth technical data sheet for the PGH-3X internal gear pump family is RE 10227.

Frequently Asked Questions

What is the displacement of this internal gear pump?
Bosch Rexroth specifies a geometric displacement of 50.7 cm³ per revolution for nominal size 050.

What is the current maximum operating pressure?
The current Bosch Rexroth product page and PGH-3X selector list 280 bar for the size 050 configuration.

What is the maximum flow?
Bosch Rexroth lists a maximum volume flow of 150 l/min for material number R901147104.

What is the rotation direction?
The pump rotates clockwise when viewed from the drive-shaft side.

Does the pump have a through-drive?
Yes. Bosch Rexroth lists this configuration with a through-drive, allowing approved pump combinations.

What is the product weight?
Bosch Rexroth lists an unpacked weight of 17.56 kg.

What should be checked before ordering?
Verify the complete PGH4-3X/050RE11VU2 model, material number R901147104, 50.7 cm³/rev displacement, clockwise rotation, Ø25 mm keyed shaft, U2 two-hole mounting flange, FKM seals, through-drive, pressure requirements, and hydraulic-fluid compatibility.

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