Overview
ISO 20516:2007 - Rolling bearings - Aligning thrust ball bearings and aligning seat washers - Boundary dimensions specifies the boundary (overall) dimensions for single-direction and double-direction aligning thrust ball bearings, both with and without aligning seat washers. The standard provides nominal dimensional data, symbols and figures (Figures 1–4) and tabulated values (Tables 1–6) that engineers and manufacturers use to ensure interchangeability and correct mounting where axial load support and accommodation of angular misalignment are required.
Key topics and technical requirements
- Scope: Dimensions for single‑direction and double‑direction aligning thrust ball bearings, and for aligning seat washers and shaft/central washers.
- Dimension tables: Nominal values are provided in Tables 1–6 for different diameter series (2, 3, 4) covering bore/outside diameters, heights (T, B, C), radii (R), chamfers (r) and other boundary dimensions.
- Symbols and notation: Symbols follow ISO 15241; terms and definitions follow ISO 5593. Figures show the positional context of each symbol.
- Chamfer and back‑face rules: Chamfer maximums relate to ISO 582; while the exact chamfer shape is not prescribed, the chamfer contour in an axial plane shall not project beyond an imaginary circular arc tangent to the washer back face and the cylindrical surface.
- Tolerance/clearance note: Where bore (d) and outside diameter (D) nominal values are the same, tolerances must be specified to ensure clearance between the shaft‑washer outside surface and the housing bore of nominal diameter D.
- Applicability: Dimensions are nominal unless otherwise specified; the standard identifies which dimensions apply to single‑ or double‑direction bearings.
Applications and who uses this standard
ISO 20516:2007 is intended for:
- Bearing manufacturers - design and production of aligning thrust ball bearings and matching washers to standardized sizes.
- Design and mechanical engineers - selection and specification of bearings for axial load applications that require accommodation of angular misalignment.
- Procurement and quality teams - verifying that supplied bearings conform to internationally accepted boundary dimensions for interchangeability.
- Standards committees and test labs - cross‑referencing dimensional requirements and tolerances.
Keywords: ISO 20516:2007, aligning thrust ball bearings, aligning seat washers, boundary dimensions, bearing dimensions, single‑direction, double‑direction.
Related standards
- ISO 582 - Rolling bearings - Chamfer dimensions - Maximum values
- ISO 5593 - Rolling bearings - Vocabulary
- ISO 15241 - Rolling bearings - Symbols for quantities
These normative references are indispensable for correct application of ISO 20516:2007.