Deutsches Institut fur Normung e. V.

Rolling bearings; Gauging methods for dimensional and running tolerances
 N 620-1

Annotation

Field of application and purpose

Concepts relating to dimensions and tolerances for rolling bearings are defined in DIN ISO 1132, but not the gauging methods by which these tolerances can be measured in conformity with the definitions.

The purpose of this standard is therefore to specify methods by means of which rolling bearing tolerances can be measured in conformity with the definitions even outside special measuring laboratories.

The tolerances defined in DIN ISO 1132, the numerical values of which are laid down in DIN 620 Part 2, Part 3 and Part 6, apply as a general rule to individual bearing components immediately after manufacture, for parts which are not subjected to external forces, including measuring forces. They represent tolerances for the final inspection of the components concerned by the manufacturer, and in particular they do not allow any direct conclusions to be drawn in respect of the correct functioning of the bearings.

In accordance with this standard, deviations can be made from the gauging methods free of measuring forces, on condition that the deformation in the direction of measurement caused by the measuring force and by the dead weight of the component concerned amounts to less than 10% of those tolerances which are being checked in respect of compliance.

It is presupposed that the condition specified in subclause 1.3 is being complied with in the case of the gauging methods described in clauses 4 and 5, with the measuring forces laid down in subclause 2.3.3. As regards bearing components which exhibit small cross sections only, and which are therefore more prone to deformation, it will be necessary to adopt other gauging methods, preferably methods free of measuring forces.