Designations of rolling bearings consist of combinations of figures and/or letters, the significance of which is not immediately apparent. Therefore, the SKF designation system for rolling bearings will be described and the significance of the more common supplementary designations explained. Very specific bearing types, such as fixed-section bearings, slewing bearings or linear bearings are not covered. These designations differ sometimes considerably from the system described here.
Bearing designations are divided into two main groups: designations for standard bearings and designations for special bearings. Standard bearings are bearings that normally have standardized dimensions, whereas special bearings have special dimensions dictated by customer demands. These customized bearings are also referred to as "drawing number" bearings and they will not be covered in detail in this section.
The complete designation may consist of a basic designation with or without one or more supplementary designations (fig 1). The complete bearing designation, i.e. the basic designation with supplementary designations is always marked on the bearing package, whereas the designation marked on the bearing may sometimes be incomplete, e.g. for manufacturing reasons.
Basic designations identify the
  • type
  • basic design
  • standard boundary dimensions
of a bearing. Supplementary designations identify
  • bearing components and/or
  • variants having a design and/or feature(s) that differ in some respect from the basic design.
Supplementary designations may precede the basic designation (prefixes) or follow it (suffixes). Where several supplementary designations are used to identify a given bearing, they are always written in a given order (fig 2).
The list of supplementary designations presented in the following is not exhaustive, but includes those most commonly used.
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