Product Description
NEWORLD's range of solutions for rolling mills can help you meet the demands of increased productivity and quality in cost-effective ways. Our specialized bearings can handle the high loads and harsh environments, while our seals and automatic lubrication solutions let you cut the costs and environmental impact associated with use and disposal of lubricants.
Four-row tapered roller bearings can accommodate combined (radial and axial) loads at low to moderate speeds. They are used almost exclusively in work roll applications such as rolling mills.
NEWORLD manufactures four-row tapered roller bearings in the TQO and TQI designs in the following variants:
● TQO design bearings (face-to-face arrangement, fig. 1):
◌ open or sealed
◌ with cylindrical or tapered bore
◌ with or without inner ring extension on both sides
◌ with or without helical groove in the bore
◌ basic design
● TQI design bearings (back-to-back arrangement, fig. 2):
◌ with cylindrical or tapered bore
◌ with or without inner ring extension on one side
TQO design bearings
TQO design bearings have two pairs of tapered roller and cage assemblies. The two rows of rollers of each pair are arranged face-to-face. Because TQO is the most widely used four-row tapered roller bearing design, NEWORLD manufactures this design in many variants, such as:
| Design variant | Characteristics |
TQON
 | · two double row inner rings · four single row outer rings · without intermediate rings · steel window-type cages |
TQO | · two double row inner rings · one double row and two single row outer rings · intermediate rings between the outer rings and between the inner rings · steel window-type cages |
TQON.1 | · two double row inner rings · four single row outer rings · without intermediate rings · steel pin-type cages (pierced rollers) |
TQO.1 | · two double row inner rings · one double row and two single row outer rings · intermediate rings between the outer rings and between the inner rings · steel pin-type cages (pierced rollers) |
TQOEN | · two double row inner rings, extended on one sideo inner ring extensions on both sides of the bearing are designed as counter-surfaces for radial shaft seals · four single row outer rings · without intermediate rings · steel window-type cages |
TQOE | · two double row inner rings, extended on one sideo inner ring extensions on both sides of the bearing are designed as counter-surfaces for radial shaft seals · one double row and two single row outer rings · intermediate rings between the outer rings and between the inner rings · steel window-type cages |
TQOT | · two double row inner rings · one double row and two single row outer rings · intermediate rings between the outer rings· steel window-type cages · tapered bore, taper 1:12o if an interference fit is required on the roll neck |
TQOSN | · two double row inner rings · four single row outer rings · without intermediate rings · steel window-type cages · sealed on both sides |
TQOSNP | · two double row inner rings · four single row outer rings · intermediate rings between the two inner rings and the two middle outer rings · steel window-type cages· sealed on both sides |
TQOS | · two double row inner rings· one double row and two single row outer rings · intermediate rings between the outer rings and between the inner rings · steel window-type cages· sealed on both sides |
TQOSN.1 | · two double row inner rings · four single row outer rings · without intermediate rings · steel pin-type cages (pierced rollers) · sealed on both sides |
TQOESN | · two double row inner rings, extended on one sideo inner ring extensions on both sides of the bearing are designed as counter-surfaces for radial shaft seals · four single row outer rings · without intermediate rings · steel window-type cages · sealed on both sides |
TQOES | · two double row inner rings, extended on one sideo inner ring extensions on both sides of the bearing are designed as counter-surfaces for radial shaft seals · one double row and two single row outer rings · intermediate rings between the outer rings and between the inner rings · steel window-type cages · sealed on both sides |
TQI design bearings
TQI design bearings have two pairs of tapered roller and cage assemblies. The two rows of rollers of each pair are arranged back-to-back. These bearings provide relatively stiff bearing arrangements, which can also accommodate tilting moments. In those applications the bearings are generally mounted with an interference fit on the roll neck by applying a bearing design with a tapered bore.
TQI design bearings are also used for vertical rolls of universal mills. In this case a bearing with a cylindrical bore is required because the inner rings have a loose fit on their seat and the outer rings are mounted with an interference fit in the chocks.
Examples of TQI design variants:
| Design variant | Characteristics |
TQIN | · one double row and two single row inner rings · two double row outer rings · without intermediate rings · steel window-type cages |
TQI | · one double row and two single row inner rings · two double row outer rings · intermediate ring between the outer rings · steel window-type cages |
TQI.1 | · one double row and two single row inner rings · two double row outer rings · intermediate ring between the outer rings · steel pin-type cages (pierced rollers) |
TQIT | · one double row and two single row inner rings · two double row outer rings · intermediate ring between the outer rings · steel window-type cages· tapered bore, taper 1:12 or 1:30o if an interference fit is required on the roll neck |
Sealed bearings
Features
● provide, compared to open bearings, the following general advantages:
◌ extended bearing service life
◌ improved reliability
◌ reduced maintenance
◌ reduced lubricant consumption (by up to 90%)
◌ reduced environmental impact
◌ less surplus grease to contaminate the milling emulsion, to improve both the rolling process and
product quality
● are the preferred solution for rolling mills
● are a simple replacement for open bearings because they have the same external dimensions
and, depending on the seal design, even have the same load carrying capacity
● have grooves with an O-ring in the bearing outside surface, which prevents any contaminants
from entering between the outer rings and the chock bore
● are fitted on both sides with one of the following seal designs:
◌ standard FKM seal design (fig. 3)
◌ standard HNBR seal design for SKF Explorer bearings (fig. 4)
◌ upgraded HNBR seal design for SKF Explorer bearings (fig. 5)
● are identified by the design suffix S
Relubrication features
Sealed four-row tapered roller bearings can be relubricated via the following relubrication features or a combination of them:
● lubrication holes in the outer ring and in the intermediate rings between the outer rings (fig. 7)
● lubrication grooves in the ring side faces:
◌ via the outer rings only when a seal is fitted between the inner rings (fig. 8), e.g. designation suffix
VA901 or E(8)1
◌ via the outer and/or inner rings when fitted without a seal between the inner rings (fig. 9), e.g.
designation suffixes VA903 or E3
● lubrication groove and holes in the inner ring and gap between the inner rings (fig. 10)
● lubrication holes in the inner ring shoulders next to the seals (fig. 11)
Sealed bearings with the designation suffix VA902 or E2 have no relubrication features (fig. 12).
Application
Cages
NEWORLD four-row tapered roller bearings are fitted with either four pressed steel window-type cages (fig. 14) or four steel pin-type cages (pierced rollers, fig. 15).
Temperature limits
The permissible operating temperature for four-row tapered roller bearings can be limited by:
● the dimensional stability of the bearing rings and rollers
● the cages
● the seals and O-rings
● the lubricant
Where temperatures outside the permissible range are expected, contact NEWORLD.
Bearing rings and rollers
NEWORLD four-row tapered roller bearings are heat stabilized up to 150 °C (300 °F).
Cages
Steel cages can be used at the same operating temperatures as the bearing rings and rollers.
Seals and O-rings
The permissible operating temperature for seals depends on the seal material:
● HNBR: –40 to +150 °C (–40 to +300 °F)
● FKM: –30 to +200 °C (–20 to +390 °F)
Typically, temperature peaks are at the seal lip.
O-rings are made of NBR and their permissible operating temperature limits are –40 to +100 °C (–40 to +210 °F). Temperatures up to 120 °C (250 °F) can be tolerated for brief periods.
Features and benefits
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, SKF Explorer 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 (fig. 1) 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.
Applications
• Heavy plate mills
• Roughing mills
