What is a double roller bearing?

Two-row, or double-row, cylindrical bearings are designed for additional strength in carrying radial loads. These bearing types are interchangeable so the dimensions and diameter under the rollers (NNU style) and diameter over the rollers (NN style) are held to an ISO/DIN standard.

What is a double shielded bearing?

ZZ (double shields) Very similar to the 2RS construction, shielded bearings have metallic enclosures rather than rubber seals. These shields are secured to the outer ring and rotate with it, maintaining a close running clearance to the inner ring.

Are Sealed bearings better than open bearings?

Richard Picard, field applications engineer at NMB Technologies Corporation explains that compared to open bearings, shielded and sealed bearings provide better protection from contamination and also add protection against lubrication migration.

Where are double row roller bearings used?

Double row tapered roller bearings are typically used in gearboxes, hoisting equipment, rolling mills and machines in the mining industry, e.g. tunnelling machines.

Do double sealed bearings need grease?

Single shielded bearings do need to be regreased per the manufacturer’s directions; but double shielded bearings are typically the “Lubricated for Life” design and usually do not require regreasing.

Why is sealed bearing better?

We use sealed so the bearings are protected from road debris and weather, so they spin cleaner and with less friction for longer. Sealed bearings perform as well or better than loose bearings, without the maintenance.

Should you grease a sealed bearing?

FOR STARTERS, note that most sealed bearings come pre-greased from the factory with a 25%-35% grease fill. This is all the grease the bearings will ever need, because the relubrication interval (explained below) is longer than the expected life of the bearing.