GB/T 275-2015Rolling bearings—Fits (English PDF)

Foreword

This Standard is drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard replaces GB/T 275-1993 "Shaft and housing fits for rolling bearings", and compared with GB/T 275-1993, the main technical changes are as follows.

- MODIFY the standard name (see cover and the first page of this Standard, and cover and the first page of 1993 edition);

- MODIFY the representation method for bearing tolerance grade code (see Clause 1 and Table 6 of this Standard, and Clause 1 and Table 6 of 1993 edition);

- REFINE and REORGANIZE the basic principles of fit selection (see Clause 3 of this Standard, and Clause 3 of 1993 edition);

- ADD the table of "Ferrule operation and bearing situations" (see Table 1);

- MODIFY the division criterion of the size of radial bearing loads (see Table 2 of this Standard, and Table 1 of 1993 edition);

- REFINE the examples in the table of the fits between radial bearings and shafts and bearing pedestal holes (see Table 3 and Table 4 of this Standard, and Table 2 and Table 3 of 1993 edition);

- MODIFY the reference marking symbols (see Figure 4 of this Standard, and Figure 4 of 1993 edition);

- DELETE the surface roughness code Rz and its values (see Table 7 of 1993 edition);

- ADD the geometrical tolerances of bearing pedestal holes with a diameter of 500 mm or more and the roughness of the fitting surface (see Table 7 and Table 8);

- MODIFY the nature of the annex; ADD the calculated value of the fits between radial bearings (excluding the tapered roller bearing) and bearing pedestal holes with a diameter of 500 mm or more (see Annex A of this Standard, and Annex A of 1993 edition);

- DELETE the calculated values of the fits between tapered roller bearings with a nominal diameter of 400 mm to 500 mm and shafts (see Table A.5 of 1993 edition).

1 Scope

This Standard specifies the basic principles and requirements for the selection of fits between rolling bearings (hereinafter referred to as "bearings") and shafts and bearing pedestal holes under general working conditions.

NOTE: General working conditions refer to the conditions that the host machine has no special requirements for the rotation accuracy, operation stability, working temperature, etc.

The fits specified in this Standard apply to the following circumstances.

a) the boundary dimension of the bearing complies with GB/T 273.1-2011, GB/T 273.2-2006, GB/T 273.3-2015, and the nominal diameter d <= 500 mm;

b) the bearing tolerance complies with Class 0, 6(6X) in GB/T 307.1-2005;

c) the bearing clearance complies with the N group in GB/T 4604.1-2012;

d) the shaft is a solid or thick-walled steel shaft;

e) the bearing pedestal is made of steel or cast iron.

This Standard does not apply to non-inner (outer) ring bearings and bearings for special purpose (such as aircraft frame bearings, instrument bearings, machine tool spindle bearings, etc.).

2 Basic principles of fit selection

3 Tolerance interval selection