A4VTG090HW100/33MRNC4C92F0000A Bosch Rexroth 90cc High Pressure Piston Pump

Product Overview

The Bosch Rexroth A4VTG090HW100/33MRNC4C92F0000A belongs to the A4VTG Series 33, NG90 range of high-pressure variable displacement axial piston pumps.

Rexroth technical documentation RE 92013/04.08 defines the A4VTG as a swashplate variable displacement axial piston pump for closed-circuit hydrostatic drives, specifically positioned for drum drives in mobile concrete mixers. The Series 33 range covers NG71 and NG90 sizes with a 400 bar nominal pressure and 450 bar peak pressure.

The NG90 configuration provides 90 cm³/rev maximum displacement, integrated boost-pump functionality, high-pressure relief protection and bidirectional variable displacement through the swashplate.

The HW1 configuration is identified by Rexroth as hydraulic proportional control with mechanical servo, using a rear-facing hydraulic hex shaft and lever.

For aftermarket replacement, complete configuration matching is essential. The replacement unit should be verified against the nameplate, material number, rotation, mounting flange, shaft, boost-pump arrangement and final ordering-code suffix.

Our replacement units can undergo 100% simulated working-condition testing to validate flow, pressure response, displacement control, boost pressure and leakage before shipment.

Technical Specifications

A4VTG090HW100/33MRNC4C92F0000A

• Brand: Bosch Rexroth
• Series: A4VTG Series 33
• Nominal Size: NG90
• Pump Type: Variable displacement axial piston pump
• Circuit: Closed circuit
• Design: Swashplate variable displacement
• Maximum Displacement: 90 cm³/rev
• Boost Pump Displacement: 27 cm³/rev
• Nominal Pressure: 400 bar
• Peak Pressure: 450 bar
• Maximum Continuous Speed at Vg max: 3050 rpm
• Minimum Speed: 500 rpm
• Theoretical Flow at 3050 rpm and Vg max: 275 L/min
• Theoretical Power at 400 bar: 183 kW
• Torque at 400 bar: 573 Nm
• Torque at 100 bar: 143 Nm
• Rotary Group Inertia: 0.0149 kg·m²
• Maximum Angular Acceleration: 18,000 rad/s²
• Filling Capacity: approximately 1.2 L
• Reference Weight without Through Drive: approximately 53 kg
• Control: HW1 Hydraulic Proportional Control with Mechanical Servo
• Control Lever: Hydraulic hex shaft with rear lever
• Control Ports: X1 / X2
• Series: 33
• Thread Design: Metric
• Rotation: R = Clockwise
• Seal: N = NBR, with FKM shaft seal
• Mounting Flange: C4 = SAE J744, 127-4
• Shaft: C92 = 1-1/2 in splined shaft, 23 teeth, 16/32 DP, with coupling flange
• Boost Pump: F = Integrated boost pump
• Through Drive: 0000 = Without through drive
• High-Pressure Valve: A = Direct-operated high-pressure relief valve
• Primary Application: Mobile concrete mixer drum drive

Important Ordering-Code Note

The supplied string ends at:

A4VTG090HW100/33MRNC4C92F0000A

Publicly indexed parts data associate R902155546 with the longer configuration:

A4VTG090HW100/33MRNC4C92F0000AS-0

The Rexroth ordering structure shows additional fields for boost-circuit filtration and the standard/special execution suffix. Therefore, the exact nameplate or Rexroth material number should be used for final purchasing verification.

Key Technical Advantages

1. 400 Bar Nominal Pressure with 450 Bar Peak Capability

The A4VTG Series 33 uses a 400 bar nominal / 450 bar peak pressure platform.

Rexroth defines peak pressure as the maximum operating pressure permitted for short-term operation, with t < 1 second. Therefore, 450 bar should not be marketed as a continuous-duty pressure rating.

2. Closed-Circuit Swashplate Architecture

The swashplate changes displacement continuously from zero toward maximum displacement. When the swashplate passes through neutral, hydraulic flow direction changes smoothly.

This makes the A4VTG well suited to reversible hydrostatic drives requiring controlled forward/reverse rotation and variable speed.

3. HW1 Hydraulic Mechanical-Servo Control

The HW1 configuration uses hydraulic proportional control with a mechanical servo.

The published control characteristics include:

• Approximately 0° to ±29° lever movement for 0 to ±Vg max
• Mechanical stop at approximately ±40°
• Control-lever movement torque of approximately 0.85–2.1 Nm
• Maximum lever torque of 7 Nm

4. Integrated Boost Pump

The F configuration specifies an integrated boost pump.

For NG90, the theoretical boost-pump displacement is 27 cm³/rev. The published boost-pressure values are 22 bar standard setting at 1500 rpm, 30 bar nominal and 40 bar peak.

5. Dual High-Pressure Relief Protection

The A4VTG is equipped with two high-pressure relief valves on the high-pressure ports. These valves protect the hydrostatic transmission against overload and also act as boost valves.

6. Heavy-Duty C92 Spline Interface

The C92 shaft configuration uses a 1-1/2 in, 23-tooth, 16/32 DP spline with coupling flange.

This configuration must be matched carefully with the mixer gearbox or coupling assembly during replacement.

7. High Hydraulic Power Density

At 90 cm³/rev, 3050 rpm and 400 bar, the NG90 version provides a theoretical flow of approximately 275 L/min and a theoretical hydraulic power level of 183 kW.

8. Defined Dynamic Characteristics

Rexroth specifies a rotary-group inertia of 0.0149 kg·m² and a maximum angular acceleration of 18,000 rad/s² for NG90.

These parameters are useful when engineering engine, coupling, gearbox and pump dynamic compatibility.

9. Conservative Material Claims

The available RE 92013 document does not publish exact alloy grades or component hardness values for the cylinder block, piston, swashplate or valve plate.

Therefore, an accurate technical page should focus on the verified architecture, interfaces, control system, sealing configuration and performance data rather than inventing material specifications.

Application Areas

Primary Application

• Mobile Concrete Mixers
• Concrete Mixer Drum Drives

The Rexroth technical documentation specifically identifies the A4VTG Series 33 as a pump for drum drives in mobile concrete mixers.

Functional Applications

The closed-circuit variable architecture is suitable for:

• Forward drum rotation
• Reverse drum rotation
• Variable drum speed
• Controlled acceleration and deceleration
• High-torque low-speed drum operation

For SEO positioning, the most relevant application keywords are therefore A4VTG090 + concrete mixer + drum drive + closed circuit.

Expert Maintenance Tips

1. Fill and Bleed the Pump Before Operation

Rexroth installation instructions require the axial piston unit to be filled with hydraulic fluid and air-bleeded during commissioning and operation. This also applies after extended standstill periods. 2. Route Case Drain Correctly

The internal case drain must return to the tank through the highest tank connection, T1 or T2.

The suction line and case drain line should enter the reservoir below the minimum fluid level.

3. Maintain Inlet Pressure

Published installation data specify:

• Minimum suction pressure: 0.8 bar absolute
• Cold-start minimum: 0.5 bar absolute

Suction restriction, reservoir level and oil viscosity should therefore be checked before high-speed operation.

4. Do Not Use 450 Bar as Continuous Pressure

Maintain the distinction between:

• 400 bar: nominal pressure
• 450 bar: short-term peak pressure

The 450 bar rating is not an unlimited continuous operating condition.

5. Inspect the C92 Coupling Spline

Before installation, inspect:

• Spline wear
• Coupling backlash
• Shaft concentricity
• Axial positioning
• Gearbox input-shaft condition
• Mounting-face alignment

The C92 shaft is a defined 1-1/2 in, 23-tooth, 16/32 DP interface and should be matched exactly.

6. Align the HW Control Lever Correctly

Rexroth notes that the mounting position of the control lever may not be fixed at delivery and may need customer alignment.

Verify:

• Neutral position
• Full forward displacement
• Full reverse displacement
• Mechanical stop
• Linkage clearance

before commissioning the mixer.

7. Maintain Effective Hydraulic Filtration

Rexroth documentation emphasizes that filtration efficiency directly affects hydraulic cleanliness. More demanding systems may require higher filtration efficiency than simple suction-filtered circuits.

Before installing a replacement pump, inspect:

• Boost-circuit filtration
• Reservoir contamination
• Filter-element condition
• Metallic debris
• Suction restriction

8. Verify Boost Pressure

The NG90 boost-pump configuration provides:

• 27 cm³/rev boost displacement
• 22 bar standard setting at 1500 rpm
• 30 bar nominal boost pressure
• 40 bar peak boost pressure

These values belong to the boost circuit and must not be confused with the 400/450 bar main hydraulic pressure ratings.

9. Verify the Complete Ordering Code

For purchasing and replacement, the customer should provide:

• Pump nameplate
• Rexroth material number
• Complete type code
• Rotation
• Shaft/coupling configuration
• Mixer gearbox model

The publicly indexed R902155546 reference corresponds to A4VTG090HW100/33MRNC4C92F0000AS-0, indicating that the supplied code may be abbreviated.

For an equivalent replacement unit, 100% simulated working-condition testing can be used to verify displacement response, flow, pressure behavior, boost pressure, lakage, rotation and load stability before delivery.