Accessories & maintenance

Frequently asked questions — Accessories

• Why should KM lock nuts and MB lock washers be ordered together?

  KM lock nuts conforming to the DIN 981 standard and MB lock washers in accordance with the DIN 5406 standard form a standardised, inseparable pair for the axial locking of bearings. The MB washer inserts a tab into the shaft groove, while its peripheral teeth bend over the nut to secure the assembly. This technical combination mechanically prevents any loosening of the bearing on the threaded shaft, thereby ensuring the stability of the industrial assembly when subjected to vibrations and mechanical stresses in service.
• What is the function of H and HE adapter sleeves compared with a standard fitting?

  H and HE series adapter sleeves make it possible to mount tapered-bore bearings, identified by the K suffix, on standard cylindrical shafts. The sleeve is tightened via a KM nut, creating a frictional contact pressure that locks the bearing onto the shaft. Unlike a direct cylindrical mounting, this system offers precise adjustment and easier dismounting when operating or maintenance conditions require it, particularly through the complementary use of AH withdrawal sleeves for subsequent interventions.
• In which cases should HMV hydraulic nuts be used?

  HMV hydraulic nuts are recommended for mounting large-dimension bearings, specifically beyond the M100 size. This device uses oil pressure injection to apply a controlled, precise and highly reproducible tightening force. This technical choice is essential to guarantee the correct fit of large-section bearings, where manual mechanical tightening cannot reach the stress values required to ensure optimal axial positioning of the components on the shaft.
• What type of additional protection should be chosen for a heavily contaminated environment?

  To prevent the ingress of dust, swarf or splashes into the bearing, complementary seals must be installed at the front face. Available solutions include V-rings, labyrinth seals or Nilos rings. These elements form an additional mechanical barrier that reinforces the bearing's standard protection. The choice between these variants depends on the nature of the contaminants encountered and the specific configuration of the working environment, in order to maximise the service life of the component.
• How can the dismounting of a tightly fitted bearing be made easier?

  Dismounting bearings that have been fitted with significant tightening can prove complex without suitable equipment. For these operations, the use of the TMHS hydraulic puller is the safest method for removing components without damaging the surfaces of the shaft or the bearing. When a hydraulic system is not required, jaw pullers represent the conventional mechanical alternative. It is also advisable to anticipate future removal operations during the initial mounting phase by incorporating AH series withdrawal sleeves.