GM5-20-AF13R-20 Parker Hydraulic Gear Motor

Product Overview

The GM5-20-AF13R-20 is a Parker G5 / GM5 Series fixed-displacement hydraulic gear motor designed for compact and reliable hydraulic rotary drive applications.

According to Parker’s official G5/GM5 catalogue, the G designation refers to gear pumps, while GM identifies the gear motor configuration. The GM5-20 has a theoretical displacement of 19.9 mL/rev, a continuous working pressure of 20 MPa, a maximum transient pressure of 24 MPa, a rated speed of 2000 rpm, and a no-load speed of 3100 rpm. Its theoretical output torque is 63.4 N·m at continuous working pressure.

The GM5 design is well suited to hydraulic rotary drives where straightforward fixed-displacement operation, compact packaging and standardized mechanical configurations are required.

For replacement applications, matching the basic GM5-20 displacement is not sufficient. Engineers should verify the complete part number, mounting configuration, shaft arrangement, rotation and port configuration before approving a true drop-in replacement.

Technical Specifications

GM5-20-AF13R-20

• Brand: Parker
• Series: G5 / GM5 Series
• Product Type: Hydraulic Gear Motor
• Model: GM5-20-AF13R-20
• Theoretical Displacement: 19.9 mL/rev
• Continuous Working Pressure: 20 MPa
• Maximum Transient Pressure: 24 MPa
• Minimum Speed at Maximum Pressure: 500 rpm
• Rated Speed: 2000 rpm
• No-Load Speed: 3100 rpm
• Theoretical Output Torque: 63.4 N·m
• Approximate Weight: 2.5 kg
• Approximate Weight with Front Bearing: 3.2 kg
• Control Method: Fixed displacement
• Rotation: R configuration; verify against the original installed motor
• Configuration: AF13R-20; verify complete mounting and shaft configuration before replacement

All numerical performance values above are from Parker’s published GM5 motor performance data.

GM5 Series Displacement Range

Parker’s official GM5 motor data lists:

• GM5-5: 5.2 mL/rev
• GM5-6: 6.4 mL/rev
• GM5-8: 8.1 mL/rev
• GM5-10: 10.0 mL/rev
• GM5-12: 12.6 mL/rev
• GM5-16: 15.9 mL/rev
• GM5-20: 19.9 mL/rev
• GM5-25: 25.0 mL/rev

The official pump table separately lists G5-30 at 30.1 mL/rev. Therefore, GM5-30 should not be presented as an officially verified GM5 motor specification without additional manufacturer documentation.

Key Technical Advantages

Fixed-Displacement Hydraulic Drive

GM5-20 uses a fixed-displacement gear-motor architecture, making it suitable for hydraulic systems requiring predictable displacement and straightforward rotary output.

20 MPa Continuous Pressure Rating

The published continuous pressure rating is 20 MPa, with 24 MPa specified as the maximum transient pressure. For system design, the continuous rating should be treated as the primary sustained operating limit.

Predictable Flow-to-Speed Relationship

The theoretical motor speed is governed primarily by hydraulic flow and displacement:

n ≈ Q / Vg

For the 19.9 mL/rev GM5-20, this provides a practical basis for matching motor displacement to the machine’s hydraulic flow requirement.

Optional Front-Bearing Configuration

Parker provides separate weight figures for standard and front-bearing versions. The GM5-20 is approximately 2.5 kg, increasing to approximately 3.2 kg with the front-bearing configuration.

This configuration should be checked carefully when the motor drives externally loaded mechanical components.

Configuration-Based Interchangeability

The G5/GM5 product family uses coded model configurations to identify mechanical and connection variants. Consequently, full part-number matching is much more reliable for replacement engineering than matching the base displacement alone.

Compact Gear Motor Architecture

The G5/GM5 family is intended for hydraulic pump and motor applications in mobile and industrial machinery. Standardized configurations and compact construction support integration into space-constrained hydraulic systems.

Application Areas

Typical applications for the GM5-20 hydraulic gear motor include:

• Agricultural machinery
• Material handling equipment
• Conveyor drives
• Compact hydraulic power systems
• Auxiliary rotary drives
• Construction machinery attachments
• Industrial machinery
• Hydraulic rotary mechanisms

For chain, sprocket, pulley or gear drives, the external mechanical load on the output shaft should also be verified during the selection process.

Expert Maintenance Tips

Verify rotation before commissioning.
The rotation designation is part of the motor configuration. Always compare the installed flow direction and required shaft rotation with the original motor.

Prime the motor before initial start-up.
Avoid dry running during installation and commissioning. Proper hydraulic oil supply is essential for lubrication, cooling and protection of internal rotating components.

Inspect fluid cleanliness and air ingress.
Contaminated oil or aeration can increase noise, accelerate wear and reduce hydraulic performance. Check filters, hoses, fittings and reservoir conditions during service.

Do not treat transient pressure as a continuous operating rating.
For GM5-20, Parker specifies 20 MPa continuous pressure and 24 MPa maximum transient pressure. Long-term operation near the transient rating requires additional engineering verification.

Verify the complete part number for replacement.
A GM5-20 displacement match does not automatically guarantee interchangeability. Confirm mounting, shaft configuration, rotation and connection details before installation.