Rolling bearings — Insert bearings and eccentric locking collars
1Key Takeaways
This document specifies the dimensional and geometrical characteristics, boundary dimensions and tolerances of insert bearings and eccentric locking collars and the radial internal clearances of insert bearings.
2Expert Interpretation
This article provides an in-depth interpretation of the geometric product specification (GPS) for insert bearings and eccentric locking rings in the ISO 9628:2019 international standard. It covers technical requirements such as boundary dimensions, tolerance values, radial internal clearance, etc. for diameter series 2 and 3, and provides structured comparison tables and implementation recommendations, which are suitable for professionals in the fields of bearing design, manufacturing and testing.
Analysis of the core content of the standard
The third edition of ISO 9628:2019 replaces the second edition of 2006. The main technical changes include: adding diameter series 3 specifications, correcting the fractional expression of 28.575mm, introducing D dimension tolerance to achieve interchangeability of bearings from different manufacturers, and applying the GPS system. The standard applies to the dimensional and geometric characteristics of insert bearings and eccentric locking rings.
Definition of key parameters
| Symbol | Parameter Description | Measurement basis |
|---|---|---|
| d | Nominal aperture of inner ring | Two-point sizing method |
| Δdmp | Medium diameter deviation of inner ring aperture | Any cross section |
| Vdsp | Range of two-point sizing of inner ring aperture | Maximum 50μm |
| H | Eccentricity | Relative to the inner ring reference axis |
Diameter series comparison
Diameter series 2: Covering 12-180mm aperture, spherical outer diameter tolerance range is -11μm to -35μm. Typical applications include agricultural machinery and conveyor belt systems.
Diameter series 3: New 25-300mm large aperture specifications, outer ring width increased by 15%-20%, suitable for heavy industrial equipment such as mining machinery.
Tolerance Requirements
| Parameters | Diameter Series 2 | Diameter Series 3 |
|---|---|---|
| Aperture Tolerance (μm) | +15/+28 | +18/+33 |
| Eccentric Locking Ring Hole Deviation | +250/+350 | N/A |
| Radial Clearance CN Group (μm) | 10-58 | 12-81 |
Implementation recommendations
- Selection guide: Prioritize metric bore diameter specifications and avoid non-preferred imperial sizes (marked with bracket values)
- Processing control: The inner ring bore diameter adopts a positive tolerance design (+15~+33μm) to adapt to the standard shaft diameter
- Detection points: The spherical outer diameter measurement should avoid the 1/4 width area of the outer ring end face
- Lubrication design: The relubrication hole should be located in the area defined by C1 and C2 (width 3-10.5mm)
Technology evolution analysis
This standard applies the GPS system to bearing geometry specifications for the first time. By introducing the two-point sizing method specified in ISO 14405-1, the interchangeability of products from different manufacturers is improved. The newly added diameter series 3 fills the standard gap for large-size insert bearings.