Four-row tapered roller bearings, TQI design

Type TQIT bearings have a tapered bore that is matched and continuous through the inner races. This allows for an interference fit on the backup rolls of high-speed mills, where a loose inner race fit of a straight bore bearing could cause excessive neck wear. The indirect mounting of the bearing pairs increases the overall effective spread of the bearing, providing optimum stability and roll rigidity. Design Attributes: Two tapered-bore single cones, one tapered-bore double cone, four single cups and three cup spacers. Front faces of single cones and both faces of double cone are extended to contact each other. Tapered cone bores are matched for continuous taper through the cones. Lubrication delivered through three cup spacers. Preset, matched assemblies, serial numbered to assure correct installation.

  • Size range: ID 123.022 mm to 1004.633 mm (4.8434 in. to 39.5525 in.) OD 174.625 mm to 2032.000 mm (6.8750 mm to 80.0000 in.)
  • Applications: Roll necks of high-speed rolling mills

Depending on their design, four-row tapered roller bearings provide the following main features and benefits:

Long service life.

The four-cup design (four separate outer rings) provides optimal load distribution over all four rows of rollers.

Enhanced operational reliability

Optimized surface finish on the contact surfaces of the rollers and raceways supports the formation of a hydrodynamic lubricant film.

Improved wear resistance

In particular, FV bearings are made of extremely clean and homogenous steel and undergo a unique heat treatment, which improve the resistance to wear.

Improved sealing performance with less leakage and less frictional heat

The optimized seal design ensures high protection against external contamination but keeps friction and frictional heat low. This seal design also provides a better retention of lubricant, minimizes environmental impact and reduces maintenance costs.

Equal load carrying capacity for sealed and open bearings

The optimized and compact seal design enables identical internal design.

Total bearing interchangeability

Bearings with and without intermediate rings as well as open and sealed bearings are available with identical external dimensions. This allows total bearing interchangeability of current standard design bearings with those without intermediate rings and/or with optimized seal design.

Separable mounting and simpler inspection

Optimized designs without intermediate rings enable to dismount and separate the cage and roller assemblies and seals. This facilitates mounting, dismounting and also maintenance inspection routines.

Axial space-saving and cost-effective solution for roll necks

The roll necks can be relatively short, no separate axial bearings are required and identically designed chocks can be used on both sides of the roll.

Simple axial location on roll necks

Tighter inner ring width tolerances facilitate the tolerancing and dimensioning of surrounding components.

Keyword: Roll neck bearings, Rolling mill bearings, Four row tapered roller bearing


DesignationPrincipal dimensions [mm]Basic load ratingsFatigue load limitDesign


BT4B 332997/HA1287.5440330.328441808500720TQIT
BT4B 332997 B/HA1287.5440330.328441808500735TQINT
BT4B 332716/HA1320422.275290261.42430808150680TQIT
BT4B 328083/HA1333.375469.9366.712328.612457011400930TQI
BT4B 334056 B/HA1368.294523.875411.162366.7125830150001160TQI
BT4B 334011368.3523.875411.162366.7125830150001160TQI
BT4B 334048/HA1384.175546.1437.96384.1756440166001290TQI
BT4B 328305/HA1391.071550428.625384.1756440166001290TQIT
BT4B 328923/HA1406.4590.55434.9753816930166001270TQI
BT4B 332813 B/HA1C425406.445565.201409.575365.1256050156001180TQI
BT4B 334047/HA1415.925590.55479.96419.17210193001430TQI
BT4B 328203/HA1419.1590.55469.9419.17210193001460TQIT
BT4B 332822/HA1453.39635496.888446.0888250220001600TQIT
BT4B 328268/HA1482.6615.95355.6317.55120153001120TQI
BT4B 332760/HA1488.95679.45533.4479.4259350255001830TQIT
BT4B 328732/HA15106554053626270190001370TQI
BT4B 332933/HA1530.225736.6579.438519.11211200310002160TQIT
BT4B 334125/HA1555.233761.873692.15536.57511700320002200TQITE
BT4B 332658/HA4581.025812.8641.35571.512100320002160TQIT
BT4B 328045/HA1604.838787.4420.688369.8888420232001660TQIT
BT4B 332934/HA1644.525857.25590.55523.87512100365002400TQIT
BT4B 332928/HA1669.925933.45725.488649.28817200490003150TQIT
BT4B 332943/HA4744.5381035.05812.8727.07520500585003600TQIT.1
BT4B 332596/HA4749.3990.665057715100455002850TQIT.1
BT4B 334099/HA4770104080065018300530003250TQITE.1
BT4B 332956/HA4777.8751079.5844.55755.6522000630003800TQIT.1
BT4B 332571/HA4863.61130.3717.55644.52519800620003750TQIT.1
BT4B 332786/HA4872.7691181.1714.375628.6520900570003550TQIT.1
BT4B 328956/HA4872.8471181.1714.375628.6520900570003550TQIT.1
BT4B 328074/HA4879.4751219.2933.45838.228100815004800TQIT.1
BT4B 332602/HA48891219.2880784.22527000780004550TQIT.1
BT4B 334081/HA4896.903126476668022900640003800TQIT.1
BT4B 332720/HA41004.6341308.1812.8730.2524600765004400TQIT.1