Bearings with a cylindrical bore
Cold dismountingSmall bearings may be removed from their seats by applying light hammer blows via a suitable drift to the ring face, or preferably by using a puller. The claws of the puller should be placed around the side face of the ring to be removed, or an adjacent component (fig 1), e.g. a labyrinth ring etc.
Dismounting is made easier if
- provision is made for slots in the shaft and/or housing shoulders to take the claws of the puller, or
- tapped holes are provided in the housing shoulders to take withdrawal screws (fig 2).
Larger bearings mounted with an interference fit generally require greater force to remove them, particularly if, after a long period of service, fretting corrosion has occurred. Use of the oil injection method considerably facilitates dismounting in such cases. This presupposes that the necessary oil supply ducts and distributor grooves have been designed into the arrangement (fig 3).
Hot dismountingSpecial induction heaters have been developed to dismount the inner rings of cylindrical roller bearings having no flanges or only one flange. They heat the inner ring rapidly without any appreciable heating of the shaft, so that the expanded ring can be removed easily. These electrical induction heaters (fig 4) have one or more coils energized by alternating current. It is necessary to demagnetize the inner rings after heating and removal. The use of electric withdrawal tools becomes economic when bearings of the same size are frequently mounted and dismounted.
When flangeless inner rings of cylindrical roller bearings, or those with only one flange, which have not to be removed frequently, or if larger sizes of inner rings (up to approximately 400 mm bore diameter) have to be dismounted, it is less costly and also easier to use a so-called thermo-withdrawal ring also referred to as a heating ring. This is a slotted ring, generally of light alloy, with handles (fig 5). The above-mentioned heaters and heating rings are available from SKF.
Additional information can be found in the section Maintenance products.
Detailed instructions for a selected bearing can be found at skf.com/mount.