Non-Contact and Contact Sealed Bearings
Types of Seal Designs:
Non-Contact Seal (NTN Suffix LB & LLB)
The LB seal is a synthetic rubber seal that is bonded to a steel backing ring, which is then fixed to the outer ring of the bearing. Both sides of the seal edge have a circular concaved surface which creates several narrow-wide gaps along the V shaped groove of the inner ring’s sealed surface. The unique design ensures a perfect labyrinth effect. This non-contacting, low friction bearing assembly requires very little rotational torque and is highly resistant to dust build up.
Normal Contact Seal (NTN Suffix LU & LLU )
The LU is also a synthetic rubber seal that is bonded to a steel backing ring, which is then fixed to the outer ring of the bearing. The seal edge forms a double lip. The inner lip touches the V-slot side of the inner ring’s seal surface. There is a slight gap between the inner ring and the outer lip which produces a labyrinth effect. Even if the friction causes the inner lip to wear, the outer lip constricts around the inner ring to compensate, and this constantly preserving the perfect sealing effect. Due to the fact that it is a contact seal bearing, the rotational torque will be larger, however the seal will provide the optimum protection from dust penetration. The increase in torque results in a 60% reduction in the limiting speed of the bearing.
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