NKE Hauptkatalog / General Catalogue 2011

DesignationSystemGeneralThe designations of rolling element bearingsconsist of combinations of letters and numbers.Although the designation system has been builtup following a logical principle the classifi cation ofindividual bearing types may sometimes be hardto understand for the layman.The designation code of rolling element bearingshas been built up in such a way that differentparts of the designation exactly identify thebearings type, size and specifi c characteristics.Besides the classification system of standardbearings, there are a large number of individualspecial bearing designations for “special”bearings or standard bearings that feature somespecial characteristics. Such special designationmay differ according to manufacturer standards.In these standard plans for each bore diameterseveral different possible outer diameters andwidths or, in the case of thrust bearings, heightshave been assigned.In this way diameter series and width series forstandard bearings have been defi ned.Some examples for the structure of standardplans are shown in fi g. 3.1.Defined in these standards are bearing base design,bore diameter (d), outer diameter (D), width (B),or, in the case of thrust bearings, height (H, T)and minimum values for chamfer dimensions (r)(fig.3.2).The basis of the rolling element bearingdesignation system is DIN-standard DIN 623.ISO StandardsBasic bearing design, their boundary dimensionsand the tolerances of standard bearings aredefined by internationally recognised standardplans (e.g. ISO 15, ISO 355 and ISO 104 reps. inDIN 616 and DIN ISO 355.) Boundary dimensionsas defined by the standard plans include bearingcross sections and their boundary dimensionsaccording to mathematical rules.Fig.3.2Fig.3.1212www.nke.at