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P31930 – Rexnord Industries Aerospace Rod Assembly
Available now on the Airparts.aero Marketplace.
The Rexnord P31930 is a high-precision, structural rod assembly engineered for flight-critical applications within the aerospace industry. Manufactured by Rexnord Industries—a global leader in specialized motion control and bearing technology—this assembly is designed to transmit mechanical force and maintain precise structural alignment between airframe components. Typically used in flight control linkages, engine control systems, or secondary structural supports, the P31930 represents the pinnacle of reliability for systems subject to high-frequency vibration and cyclic loading.
This assembly often features integrated spherical rod-end bearings (Heim joints) that allow for multi-axis misalignment while maintaining zero-backlash performance. The rod body is typically fabricated from high-strength aluminum alloy or corrosion-resistant steel, depending on the specific weight and thermal requirements of the installation zone. For the maintenance professional, the P31930 is a "fit and forget" component, designed to meet the exact kinematic profiles required by airframe OEMs to ensure smooth, predictable control response.
Key Features
Integrated Spherical Bearings: Features high-precision rod ends that accommodate structural flexing and airframe misalignment without binding.
High Strength-to-Weight Ratio: Engineered with specialized aerospace alloys to provide maximum tensile and compressive strength with minimal mass.
Adjustable Linkage Geometry: Many P31930 configurations allow for fine-tuned length adjustments with locking jam nuts, ensuring perfect rigging of flight control surfaces.
Vibration Fatigue Resistance: The materials and finishes are selected to withstand the harmonic resonances common in turbine engine environments.
Advanced Corrosion Protection: Finished with cadmium plating or specialized anodization to prevent environmental degradation in unpressurized bays.
Technical Specifications
Part Number: P31930
Manufacturer: Rexnord Industries (Aerospace Division)
Component Type: Structural Linkage / Rod Assembly
Material: High-Strength Alloy Steel or 2024/7075 Aluminum (refer to specific dash number)
End Configuration: Typically features male or female threaded rod ends with spherical bearings.
Finish: Cadmium Plate per QQ-P-416 or Anodized per MIL-A-8625.
Load Rating: Engineered for specific tensile and compressive limits (see OEM data sheet).
Governing Specifications: AS81935 / AS81820 (Standard for spherical bearings).
Certification: FAA-PMA / OEM Original Equipment.
Aircraft Compatibility
MD11
Boeing 737, 757, 767 Series: Often used in secondary flight control linkages and landing gear door mechanisms.
Airbus A320 Family: Utilized in various environmental control system (ECS) and pylon assemblies.
Bombardier & Gulfstream: Common in high-precision engine control and thrust reverser linkages.
Note: Rexnord P-series rods are used universally in commercial and business aviation. Always verify the specific application in the aircraft Illustrated Parts Catalog (IPC).
Applications
Flight Control Linkages: Transmitting pilot or actuator inputs to ailerons, elevators, and rudders.
Engine Control Systems: Modulating fuel controls or thrust reverser actuators.
Landing Gear Door Actuation: Ensuring synchronized movement of gear doors during extension and retraction cycles.
Why Choose P31930?
In the demanding environment of an aircraft, mechanical linkages are subject to constant Fretting and Oscillation. Choosing the genuine Rexnord P31930 ensures that the internal bearing clearances and material hardness are perfectly matched to the system’s design. Aftermarket "look-alike" rods often utilize inferior bearing liners that can "delaminate" or "cold-flow," leading to excessive play (slop) in the controls. The P31930 utilizes Rexnord’s proprietary Rexlon or specialized Teflon-based liners to provide a low-friction, maintenance-free life cycle, ensuring the aircraft remains in its certified rigging configuration.
The P31930 operates on the principle of Kinematic Force Transfer through a Self-Aligning Interface. The spherical bearings at the ends of the rod allow for three degrees of freedom (rotation, tilt, and swivel), which is essential because airframes are not rigid; they flex under aerodynamic loads. If a rigid rod were used, this flexing would induce Bending Moments that could snap the rod or damage the mounting brackets.
From a materials standpoint, the rod ends often utilize a Dry-Film Lubricant or a self-lubricating fabric liner (per AS81820). This eliminates the need for grease fittings in hard-to-reach areas. The rod body itself is designed to resist Buckling under high compressive loads. By using a hollow tube design, Rexnord maximizes the Area Moment of Inertia ($I$), providing high rigidity without the weight penalty of solid bar stock. This ensures that every millimeter of pilot input is translated into control surface movement with zero "sponginess."
Note: The P31930 is a flight-critical mechanical component. It must be inspected for "play" or "binding" in the rod ends during every 100-hour or annual inspection. Any evidence of cracks, bending, or liner wear beyond the limits specified in the Aircraft Maintenance Manual (AMM) is cause for immediate replacement. Installation must be performed by a certified A&P mechanic.
Documentation
| Specifications | |
|---|---|
| Cage Code | 57606 |
| ECCN / USML | 9A991.d |
