Precision locknuts are used where high axial forces must be supported and high axial runout accuracy and rigidity are required.
The thread and the axial face of the locknut in contact with the rolling bearing are produced in a single clamping operation. This allows very high axial runout accuracy to be achieved.
The available precision locknuts AM, ZM and ZMA can be used several times if handled correctly.
Axial locking by segments
Precision locknuts AM with axial locking are divided into several segments for applying the locking forces. When the hexagonal socket grub screws are tightened, the segments are elastically deformed. As a result, the thread flanks of the segments are pressed against the flanks of the shaft thread and give a high frictional force that acts to prevent loosening of the nut. The axial runout of the nut is not affected by this method of locking.
Mounting clearance with locknut AM for axial locking
Precision locknut AM
Locking by radial locking pegs
Precision locknuts ZM and ZMA are secured against rotation by means of two radially acting locking pegs. ZMA is the heavy series.
The locking pegs are manufactured together with the internal thread of the locknut. They mesh like comb teeth in the thread of the shaft without affecting the axial runout or damaging the thread.
The locking pegs are secured by grub screws with a hexagonal socket arranged concentrically over the locking pegs.
Mounting clearance with locknut ZM, ZMA for radial locking