4. ACCURACY OF BALL BEARING UNITS

4.1. Radial Internal Clearance of Insert Bearings

The radial internal clearance of the insert bearing is same with the reference value of GB/T4604-2oo6 deep groove ball bearings. Generally, the N clearance is adopted for cylindrical bore bearings and tapered bore bearings. When the environmental temperature is very high or when the temperature difference between the outer and inner rings is large, a larger clearance must be adopted because the clearance decreases due to thermal expansion of the bearings materials and temperature gradient in the bearing.

4.2. Dimensional Accuracies of Insert Bearings

The dimensional accuracy of FK insert bearings follows the dimensional accuracy prescribed

in ISO/TC4/SC6 insert bearings for ball bearing units.


d----bore diameter.

△dmp-deviation of mean bearing bore diameter in a single plane.

Vdp----variation of bearing bore diameter in a single radial plane.

△Bs---deviation of a single inner ring width.

△Cs----deviation of a single outer ring width.

Kia--radial runout of inner ring.


1). Applies in any single radial plane of the bore.

d--- bore diameter

d1---diameter at the theoretical large end of a basically tapered bore d1=d + 1/12B.

△dmp-deviation of mean bore diameter in a single plane (for a basically bore, dmp refers to the

theoretical small end of the bore).

△d1mp-deviation of mean bore diameter in a single plane at the theoretical large end of a basically

tapered bore.

Vdp----variation on bore diameter in a single radial plane.

B---inner ring width.

a-----the taper angle (half the cone angle) is

a = 2° 23' 9.4" = 2.385 94°= 0.041 643 rad.

Tolerance in distance from center line of spherical outer ring to side of inner ring.





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2025 July 4th Week FK Product Recommendation:

Air Handling Bearing Units:

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https://www.fk-bearing.com/products/Air-Handling-Bearing-Units/870.html


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