SIST EN 3059:2009

Overview

SIST EN 3059:2009 is a European standard developed by CEN that defines the specifications for rigid single row ball bearings in steel, featuring a cadmium-plated flanged alignment housing. These bearings are designed specifically for aerospace applications related to airframe rolling, focusing on slow rotations and oscillations under load. The standard ensures that bearings meet precise dimensional and load-bearing requirements essential for safety and performance in aerospace structures.

These bearings are particularly suitable for use in torsion lever hubs and separated supports within airframe systems and operate efficiently within a temperature range from -54 °C to 150 °C. When lubricated with specific grease types as outlined in EN 3727, they maintain optimal performance even under challenging environmental conditions typical in aerospace contexts.

Key Topics

• Bearing Design and Materials
  EN 3059 specifies bearings made from steel with hardened inner and outer rings (59-64 HRC hardness) and balls. The flanged alignment housing is cadmium plated for corrosion resistance, per EN 2133, with heat treatment to reduce brittleness after plating.

• Dimensions and Tolerances
  The standard includes detailed dimensional tolerances and clearances for bearing components measured in millimeters with strict limits on bore deviation, axial and radial clearances, and runout to guarantee precision in fit and function.

• Load Capacities
  Bearings are rated for static axial and radial loads, with clear load capacities defined for different displacement limits (0.1 mm, 0.15 mm, and 0.2 mm). Two types of alignment housings (solid and lightweight) have separate load tables, ensuring correct selection based on application needs.

• Operating Temperature and Lubrication
  Bearings can function between -54 °C and 150 °C, with lubrication options that influence their thermal limits:

  • Ester type very high pressure grease (code A) with operational range -73 °C to 121 °C
  • Synthetic hydrocarbons very high pressure grease (code B), general purpose, for -54 °C to 177 °C
    This distinction is crucial for ensuring bearing reliability depending on the aircraft environment.

• Surface Roughness and Treatment
  Surface roughness requirements ensure smooth raceways and supporting surfaces, contributing to long bearing life and low friction. The cadmium plating thickness is standardized at 10 to 20 microns with specified non-plated areas for functional contact.

• Marking and Designation
  Bearings are marked according to EN 2424 and designated using a structured system that encodes grease type, diameter, bearing type, and alignment housing, facilitating traceability and uniformity in aerospace supply chains.

Applications

EN 3059 bearings are engineered for critical aerospace applications, including:

• Airframe Rolling Components
  Used in the hub assemblies of torsion levers and support structures subject to slow oscillatory motion, essential for controlling aerodynamic surfaces and landing gear components.

• Aerospace Mechanical Systems
  Suitable for any airframe mechanism requiring high precision and reliable load-bearing with thermal resilience, including flight control linkages and mechanical transmissions within aircraft.

• Harsh Environmental Conditions
  Designed to withstand wide temperature fluctuations and corrosive atmospheric conditions encountered at high altitudes, thanks to cadmium plating and specialized lubrication.

Related Standards

• EN 3727 – Technical specifications for airframe rolling bearings with flanged alignment housing, providing detailed operational and testing methods to complement EN 3059.
• EN 2133 – Cadmium plating requirements for aerospace steel components ensuring corrosion resistance and mechanical integrity.
• EN 2031 / EN 2221 / EN 2222 – Steel classification and hardness standards for bearing components, reinforcing material quality compliance.
• EN 2424 – Marking of aerospace products, crucial for identification and traceability in aerospace manufacturing.
• ISO 1132-1 – Rolling bearings terminology, ensuring consistency in definitions across standards.

Keywords: aerospace bearings, rigid single row ball bearings, flanged alignment housing, cadmium plated bearings, airframe rolling bearings, aerospace standard EN 3059, bearing dimensions and loads, aerospace lubrication standards, airframe mechanical components, aerospace corrosion resistance.

SIST EN 3059:2009 provides aerospace engineers and manufacturers with a detailed and reliable framework for selecting and using high-performance rolling bearings essential to the safety and functionality of modern aircraft airframes.