Text version of the page

Bearing data – general

Needle roller bearings (4703 /IE) - 5564 Design of associatedcomponents

Dimensional, form and running accuracyof bearing seatings and abutments The accuracy of cylindrical bearing seatingson shafts and in housing bores, of seatingsfor thrust bearing washers and of the support surfaces (abutments for bearings providedby shaft and housing shoulders etc.) shouldcorrespond to the accuracy of the bearingsused. In the following, guideline values forthe dimensional, form and running accuracy are given. These should be followed whenmachining the seatings and abutments.Dimensional tolerances For bearings made to Normal tolerances,the dimensional accuracy of cylindrical seat-ings on the shaft should be at least to grade6 and in the housing at least to grade 7. For bearings with higher accuracy, correspond-ingly better grades should be used. The basic tolerances to ISO 286-1:1988 will be found in Table . Tolerances for cylindrical form The cylindricity tolerances as defined in ISO 1101-1985 should be 1 to 2 IT grades better than the prescribed dimensional toler-ance, depending on requirements. For ex-ample, if a bearing shaft seating has beenmachined to tolerance f6, then the accuracyof form should be to IT5 or IT4. Table givesguideline values for the cylindrical form toler-ance and the total runout tolerance for thedifferent bearing tolerance classes.Tolerances for perpendicularity Abutments for bearing rings should have a rectangularity tolerance as defined in ISO 1101-1983 which is better by at least one IT grade than the diameter tolerance ofthe associated cylindrical seating. For thrustbearing washer seatings, the perpendicular-ity tolerance should not exceed the values ofIT5. Guideline values for the rectangularity tolerance and for the total axial runout willbe found in the

8

Table .

Table 8

Limits for ISO tolerance gradesNominalTolerance gradesdimension IT2IT3IT4IT5IT6IT7overincl. mmµm

9

13 1,2234610 36 1,52,545812 610 1,52,546915 1018 23581118 1830 2,54691321 3050 2,547111625 5080 358131930 80120 4610152235 120180 5812182540 180250 71014202946 250315 81216233252 315400 91318253657 400500 101520274063

9

26