>> P.61
1N=0.102kgf=0.2248lbs.1mm=0.03937inchMountingPreparationWhen mounting non-separable bearings, the inner and outer rings are pressed in simultaneously by applying a cover plate as shown in Fig. 27. It must never happen that the inner ring is press-tted to the Before mounting the bearing, the dimensions and l-shaft by striking the outer ring, or the outer ring by lets of the shaft and housing should be checked to striking the inner ring, because the raceway surfaces ensure that they conform to specications.and rolling elements will be scratched or indented.Bearings should be unwrapped just before mounting. In case of grease lubrication, bearings should be lled with grease without cleaning the bearings. Even in the case of oil lubrication, it is normally unnecessary to clean the bearings. However, when high accuracy is required or when using at high speeds, the bearings should be cleaned using cleaning oil to remove thor-oughly oily contents. The cleaned bearings should not be left alone without anti-corrosive precautions, because bearings can easily be corroded after anti-corrosive agents are removed.Lubricating grease is prepacked in some types of bearings. Therefore, refer to the relevant section for each bearing.Methods of mountingMounting methods of bearings are different according to the type of bearing and the t. In general, mount-ing of needle roller bearings is comparatively easy. However, non-separable bearings with large interfer-ences should be handled with great care.1 Mounting by press fitSmall and medium bearings with small interferences require a small pressing-in force for mounting, and they are mounted using a press at room temperature. The bearing should be pressed in carefully, applying a force evenly to the bearing with a tting tool as shown in Fig. 26. For separable bearings, the inner and outer rings can be mounted separately, and the mounting work is simple. However, when installing the shaft and inner ring assembly into the outer ring, care should be taken not to damage the raceway sur-faces and rolling elements.Fig. 26Fig. 27When press fitting, the friction of the fitting surfaces can be reduced by applying high viscosity oil over the tting surfaces.The pressing-in or pulling-out force to be applied to the bearing is given on page A59.2 Mounting by shrink fittingThis method is used when the interference is great or when a large bearing is to be tted. The housing is heated and thermally expanded when tting the outer ring to the housing and the inner ring is heated and expanded when tting it to the shaft allowing the bear-ing to be set easily within a short time. The maximum allowable temperature for the shrink t is +120°C, and heating should be performed appropriately. Pure non-corrosive mineral oil is recommended as the heating oil for shrink t, and insulation oil for trans-formers is considered to be the best. During cooling, the bearing also shrinks in the axial direction. Therefore, to ensure that there is no clearance between the bearing and the shoulder, an axial force must be applied continuously to the bearing until it has cooled.When the interference between the outer ring and the housing is great, an expansion t method in which the bearing is cooled using dry ice or other cooling agent before fitting can be used. Immediately after fitting, however, moisture from the air easily condenses on the bearing. Therefore, it is necessary to take pre-ventive measures against corrosion.A58ABCDEFGHIJKLM
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