ISO 12240-2:1998

Overview

ISO 12240-2:1998, "Spherical plain bearings - Part 2: Angular contact radial spherical plain bearings", specifies the dimensions and dimensional tolerances for angular contact radial spherical plain bearings. The standard sets measurement series and numerical tolerance bands for finished bearings before any coating or plating. While producers need not follow the illustrated design, manufactured parts must conform to the dimensional and tolerance requirements. Note: airframe applications are explicitly excluded from this part.

Key topics and technical requirements

• Dimension series A: Nominal bore sizes and corresponding outside diameters, inner/outer ring widths and bearing widths are tabulated for a defined size range (dimension series A).
• Tolerance tables: Numeric tolerances are given by bore and outside-diameter ranges. These include permissible variations of:
  • Mean bore and mean outside diameter (Dmp/dmp)
  • Variation in a single radial plane (Dp/dp)
  • Single ring width deviations and total bearing width deviation (Bs/Ts)
• Chamfer specifications: Minimum chamfer sizes are listed; maximum chamfer dimensions are referenced to ISO 582.
• Finished condition basis: All tolerance values apply to finished bearings prior to any surface coatings or platings.
• Design flexibility: Bearings need not visually match the illustrated form so long as the specified dimensions and tolerances are met.

Practical applications and users

ISO 12240-2 is intended for organizations and professionals involved with the specification, manufacture, inspection and procurement of spherical plain bearings, particularly:

• Bearing manufacturers and component designers setting production tooling and inspection plans
• Quality and metrology engineers performing dimensional checks and acceptance testing
• OEMs and design engineers in industrial machinery, construction equipment, automotive steering/suspension systems and other heavy-duty radial bearing uses
• Procurement professionals creating technical purchase specifications and conformity requirements

This standard helps ensure interchangeability, predictable fit and function, and consistent manufacturing tolerances for angular contact radial spherical plain bearings used in radial load and combined radial/axial load applications (excluding airframes).

Related standards

• ISO 12240 (other parts): Part 1 (radial spherical plain bearings), Part 3 (thrust spherical plain bearings), Part 4 (rod ends)
• Normative references within ISO 12240-2: ISO 582 (chamfer dimensions), ISO 1132-1 (tolerances-terms & definitions), ISO 6811 (spherical plain bearings vocabulary)

Keywords: ISO 12240-2, spherical plain bearings, angular contact radial spherical plain bearings, dimensions, tolerances, bearing standards, radial bearings, chamfer, bearing manufacture.