Needle roller bearings (4703 /IE) - SKF Magnetic Bearings - #38

The radial internal clearance of bearing ar­rangements incorporating needle roller and cage assemblies is determined by the gauge of the needle rollers in combination with the shaft and housing raceway tolerances and the operating temperature. Suitable raceway tolerances which have been well proven in practice are given in Table 0.

If applied when using assemblies incorpor­ating rollers of standard gauge (-» Table ), the radial internal clearance will lie in the range of C2 and Normal (-» Table □ on page 21).

If a specific radial internal clearance is required in a given bearing arrangement, it is recommended that the various components of the arrangement are matched, e.g. follow­ing a matching plan as shown in Table 0. It should be observed that the mean value of the needle roller gauge should be used to calculate the internal clearance, i.e. -6 um for the gauge -5/-7 um.

The example shown in Table El will pro­duce a small operational clearance, i.e. less than normal.

The modified line contact between the raceways and the needle rollers not only prevents damaging edge stresses, but also enables single row needle roller and cage assemblies to accept minimum misalign­ments up to approximately 1 minute of arc between shaft and housing.

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5KF