REMOVE BEARING

In many instance, bearing vhane to be removed from the shaft simply to allow others parts to be removed regrettably it often happens that bearings that are ferfect before removeal for inspections or cleaning are damage during removal mounting. It is good practice only to remove bearings when strictly necessary. Baring inspections should instead be done by listening to the sound of bearing and absering the lubricant.

A bearing which is to be reused should, for endurance life reasons, always be remountd in the same relative position as before. It is therefore advisable, before dismounting, to mark the position of the bearing which side is uppermost  and which side faces the front.

Small and  medium size bearings may be dismounted using a conventional puller. If the bearing has been mounted with an interference fit on the shaft, the puller should engage the inner ring.

To avoid damage to the bearing seating. The use of a self centering puller eliminates the risk of damage, and dismounting is simpler and more rapid. Only in one cases where it is imposible to engange the inner ring is it permitted to apply the puller o the outer ring. But, and this is important, the outer ring must be rotated during dismounting so that no part of the bearing is damaged by the dismounting force. This can be doneby locking the screw and turning the puller continuously until the bearing comes free.

Dismounting the inner ring of cylindrical roller bearings can be easly done with an aluminum heating ring as shown  fig.   

 

 

The dismounting procedure is simple. First remove the outer ring with the roller and cage assembly. Coat the raceway of the inner  ring with an oxidation resistant oil. Heat ttthe aluminum ring to a temperature 121°C ( 250 ° F ), place it on the inner ring, and press the handles togheter. Use the tool to withdraw the inner ring as soon as it becomes loose. Remove the ring from the tool immediately. If the inner rings have different diameters and if dismounting is frequent, use of an induction heating tool is freferable, as shown fig.

such heaters raise the temperature of the inner ring by inducing currents. The adjustable heater is suitable for various inner ring diameters over 80 mm, depending on the manufacturer of the induction heater.

Heat the inner ring for 15 to 30 sec, until it comes loose, and the withdraw it, the inner ring  must not be heaterd o temperature above  121°C ( 250 ° F ). Switch of the current, remove the ring from the tool, and demagnetize it.

Use, open ( not sealed  or shielded ) bearings, if heavily coated wih oxidizes grease, must be thoroughly cleaned before use. He bearings should be soaked in hot, light oil at 93° to 116°C ( 200° to 240° F ), gitating the basket of bearings slowly through the oil. In extreme cases, boiling in emulsifiable cleaners diluted with water will usually soften the contaminating sludge. If the hot emulsions are used, the bearings should be drained and spun individually until the water has completely epavorated and then adequately protected.

Prior to the startup of any equipment, the bearings should be lubricated in accordance with the bearing menufacturer’s recommendation.