Page 89 of Ball and Roller Bearings by NTN Corporation Japan

bearing handling ris diff e in te bef erence mp hea ore/af bea ting ter ring 90 280 260 240 m 280 80 70 260 60 50 240 diametric expansion of inner ring bore 200 r6 40 220 220 30 inner ring 200 180 160 180 160 140 120 100 80 60 40 20 k5 j5 p6 n6 m6 140 120 100 80 60 40 20 removal pawl fig 15.6 removal of inner ring using an induction heater 50 100 150 200 250 300 350 400 450 bearing bore diameter mm 500 550 600 fig 15.5 temperature differential required for shrinkage fit of inner ring the amount of thermal expansion in any event bearings should never be heated above 120°c the most commonly used method of heating bearings is to immerse them in hot oil however this method should not be used for prelubricated shielded and sealed bearings to avoid overheating parts of the bearings they should never be brought into direct contact with the heat source but instead should be suspended inside the heating tank or placed on a wire grid if bearings are dry-heated with a heating cabinet or hot plate they can be mounted without drying for heating the inner rings of nu nj or nup cylindrical and similar type bearings without any ribs or with only a single rib an induction heater can be used to quickly heat bearings in a dry state always demagnetize when heated bearings are installed on shafts the inner rings must be held against the shaft abutment until the bearing has been cooled in order to prevent gaps from occurring between the ring and the abutment face as shown in fig 15.6 a removal pawl or tool can also be used to dismount the inner ring when using the induction heating method described above 15.2.3 installation of tapered bore bearings small type bearings with tapered bores are installed over a tapered shaft withdrawal sleeves or adapter sleeves by driving the bearing into place using a locknut the locknut is tightened using a hammer or impact wrench fig 15.7 large size bearings require considerable fitting force and must be installed hydraulically in fig 15.8 the fitting surface friction and nut tightening a installation on tapered bore b installation with adapter sleeve c installation using withdrawal sleeve fig 15.7 installation methods using locknuts fig 15.8 installation utilizing oil injection a-87

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