Tip No. 4

Preventive Measures for mounting or dismounting withdrawal sleeves

Design reasons may lead to difficulties when dismounting withdrawal sleeves.

In certain cases not the whole length of the withdrawal sleeve thread may be supported by the shaft seat. The threaded portion of the withdrawal sleeve projects over the shaft thread whose outside diameter is the same as the sleeve bore diameter. When dismounting the withdrawal sleeve with the help of a hydraulic nut the sleeve thread is contracted and presses onto the shaft thread. Thus both the shaft thread and the withdrawal sleeve bore will be damaged during the subsequent withdrawal. As a consequence the withdrawal sleeve cannot be used any more and in the worst case also the hydraulic nut thread may be damaged beyond repair. To prevent damages of the kind described in existing designs, recess shaft thread and put a split supporting ring into the groove. If the sleeve projects over the shaft end insert a thick walled supporting ring into the bore of the sleeve over the entire length of the unsupported sleeve thread. FAG offer their assistance in assessing mounting/dismounting procedures to minimize all risks involved.