EN 3291:1994

Overview

EN 3291:1994 (CEN) defines the characteristics, dimensions and load specifications for single-row self-aligning roller bearings in steel, cadmium-plated, covering diameter series 3 and 4. These bearings are designed to withstand slow rotations, oscillations and swivelling under load and are intended for use between fixed and moving parts of aircraft structures and control mechanisms.

This standard supports consistent design, selection and interchangeability of airframe rolling bearings where alignment correction and limited relative motion are required.

Key Topics

• Bearing type: Single-row self-aligning roller bearings in steel, cadmium plated.
• Diameter series: Series 3 and 4 (as specified in the standard).
• Operational conditions: Designed for slow rotation, oscillation and/or swivelling under load rather than continuous high-speed operation.
• Applications scope: Use between fixed and moving airframe parts and control mechanisms.
• Standard content focus: Dimensional specifications and load ratings that enable reliable mechanical integration and predictable load capacity.

Practical keywords: EN 3291:1994, self-aligning roller bearings, cadmium-plated bearings, airframe bearings, diameter series 3 and 4, dimensions and loads, aircraft control mechanisms.

Applications

EN 3291:1994 bearings are used where limited relative motion and alignment correction are needed in the aircraft structure. Typical application areas include:

• Hinges and pivots in flight control linkages where small oscillations or swivelling occur under load.
• Interfaces between fixed structure and moving components where alignment errors must be accommodated.
• Low-speed bearing points in landing gear linkages, control surfaces and ancillary mechanisms where cadmium plating provides corrosion-resistant surface treatment.

Benefits for engineers and maintenance teams:

• Interchangeability: Standardized dimensions enable replacement with compatible parts from different manufacturers.
• Predictable performance: Specified load ratings and dimensional data support safe design margins for slow-rotation and oscillatory duties.
• Corrosion protection: Cadmium plating offers surface treatment suitable for many aerospace environments (refer to applicable material-treatment standards).

Related Standards

For comprehensive specification and design work, EN 3291:1994 is typically considered alongside other aerospace and bearing standards covering:

• Bearing material and surface treatment standards (cadmium plating requirements and environmental considerations).
• General aerospace components and assembly standards that govern interchangeability and installation practices.
• Other EN aerospace bearing series addressing different bearing types, sizes or high-speed applications.

Consult the CEN catalog and national adoption documents for cross-references and the latest consolidated versions. For procurement and engineering decisions, combine EN 3291:1994 dimensional and load data with supplier datasheets, material treatment specifications and applicable maintenance guidance.