Self-Lube Hand book - NSK Europe - #19

Text version of the page

SELF-LUBE® BEARINGS 19 Shaft locking arrangements Set screw lock This locking arrangement consists of two knurled cup-point, self-locking, socket-head set screws fitted in the extended inner ring. For normal loads and moderate speeds simply mount the bearing unit into position and tighten down the set screws to the recommended torque value. Additional security can be achieved by spot drilling the shaft to accommodate the set screw point. When spot drilling, first remove the set screw and locate the position on the shaft. Select a drill the size of the inner ring threads minor diameter, and drill through this hole into the shaft to the depth of the drill point. Replace the set screw and tighten onto the shaft in the normal manner. The recommended tightening torques for the set screws are given on page 18. Eccentric collar lock This type of lock consists of an eccentric diameter formed on the extended inner ring of the bearing which engages a similarly formed eccentric diameter in the bore of a separate collar.Locking is achieved by turning the collar in the direction of the shaft rotation until the eccentric diameters of both collar and inner ring are fully engaged. The collar is provided with a blind hole to facilitate tightening when locking the bearing to the shaft. The set screw when tightened to the recommended torque values on page 18 prevents the collar ‘backing off’ in service. Set screw lock Eccentric collar lock Taper sleeve lock Mounting Self-Lube® adapter sleeve units ››First bolt the Self-Lube® housing to the equipment and clean the shaft and sleeve bore of any oil or grease. ››Position the shaft within the unit and tighten up the locknut by hand. If the sleeve assembly turns on the shaft tap the sleeve into the bearing to give a positive grip. Tighten locknut to recommended torque value given on page 18. ››Where torque spanner facilities are not available a blunt drift and small hammer may be used to tighten the nut. ››Check that the bearing rotates freely, to ensure that the internal clearance has not been totally removed and that preload has been avoided. ››Finally, secure the nut with the appropriate tab on the locking washer. Tighten the nut slightly if necessary but never back the nut off. ››After 100 hours running it is advisable to check the tightness of the locknut. Taper sleeve lock This locking arrangement, which incorporates a standard taper adapter sleeve, locknut and lock washer, is recommended when a positive concentric (shaft) lock is required. When fitting the bearing to the shaft, care must be taken to ensure that the locknut is not over-tightened as this can eliminate the bearing internal clearance, resulting in premature failure. A lockwasher is provided which prevents the locknut ‘backing off’ when one of the tabs is engaged with the corresponding notch in the locknut. (See below for fitting instructions). The recommended tightening torques for the locknuts are given on page 18.