Designs and variants

TDO design bearings
  • have one double row outer ring (double cup) and two inner rings with roller and cage assemblies (cones), usually with an intermediate ring between the two inner rings (fig. 1)
  • have rows of rollers arranged back-to-back (load lines diverge toward the bearing axis), which enable stiff arrangements and accommodate considerable tilting moments
  • are ready-to-mount units, manufactured with the predetermined axial clearance or preload
  • can be used either as locating or non-locating bearings:
    • for non-locating arrangements, the axial displacement should take place between the outer ring and the housing bore
    • bearings with a blind hole or locating slot in the outer ring can be used with a cylindrical pin engaged in the hole or slot to prevent the outer ring from turning in its seat

SKF manufactures TDO design bearings in many variants (→ Variants/features), such as: 

Design variantCharacteristics
TDO


  • intermediate ring between two inner rings
  • steel window-type cages
TDO.1


  • intermediate ring between two inner rings
  • steel pin-type cages (pierced rollers) for higher loads
TDON


  • without intermediate ring 
  • inner rings abut each other
  • steel window-type cages
TDO/Z


  • intermediate ring between two inner rings
  • steel window-type cages
  • sheet steel shield on both sides
TDOS.1


  • steep contact angle α
  • for applications where high axial loads or high tilting moments occur in combination with radial loads
  • intermediate ring between two inner rings
  • steel pin-type cages (pierced rollers) for higher loads
TDI design bearings
  • have two outer rings (cups) and one double row inner ring with two roller and cage assemblies (double cone), usually with an intermediate ring between the two outer rings (fig. 2)
  • have rows of rollers arranged face-to-face (load lines converge toward the bearing axis) 
  • are available open or capped with shields or seals
  • are ready-to-mount units, manufactured with the predetermined axial clearance or preload
  • are designed primarily for use as locating bearings
  • are available with a helical groove in the bore and/or lubrication grooves in the side faces of the bearing rings (fig. 3):
    • where a loose fit on the shaft is needed, these grooves counteract the disadvantage of a loose fit
    • when the inner ring turns on its seat under load, these grease-filled grooves enable lubricant to be supplied between the inner ring and seat surfaces
    • in addition, the grooves can absorb wear particles

SKF manufactures TDI design bearings in many variants (→ Variants/features), such as: 

Design variantCharacteristics
TDI


  • intermediate ring between two outer rings
  • steel window-type cages
TDI.1


  • intermediate ring between two outer rings
  • steel pin-type cages (pierced rollers) for higher loads
TDIE


  • intermediate ring between two outer rings
  • steel window-type cages
  • inner ring extensions at both sides
    • extensions are ground as counterface for seal lips
TDIT


  • intermediate ring between two outer rings
  • tapered bore, taper 1:12
  • steel window-type cages
TDIS


  • steep contact angle α
  • for applications where high axial loads in combination with radial loads occur
  • intermediate ring between two outer rings
  • steel window-type cages
  • used in rolling mill applications with a loose fit on the roll neck and only subjected to purely axial load
  • the inner ring has one or more notches in one or both side faces to prevent it from turning on its seat
  • depending on the application, the bearings can be supplied with or without an intermediate ring between the two outer rings
TDIS.1


  • steep contact angle α
  • for applications where high axial loads in combination with radial loads occur
  • intermediate ring between two outer rings
  • steel pin-type cages (pierced rollers) for higher loads
TDIS.2


  • self-retaining unit with a retention sleeve over the outer rings
  • the outer rings are pressed into the sleeve
  • the deformation of the outer rings normally resulting from heavy axial loads is considerably reduced
    • as a consequence, the stress distribution in the rolling contacts is more favourable and extends bearing service life
  • the axial internal clearance is determined by the sleeve
  • preloading by means of springs is unnecessary
  • steep contact angle α
  • for applications where high axial loads in combination with radial loads occur
  • the simplified and economic design facilitates mounting, dismounting and also maintenance inspection routines

Optional TDI design bearings composed of four-row tapered roller bearing components

On request, TDI design bearings with dimensions different from those listed in the TDI design product table can be specially created as tailored double row bearings using standard components of SKF four-row tapered roller bearings in the TQO design, but without intermediate rings (TQO design product table). For example, it is possible to combine standard components as follows (fig. 4):

  • two single row outer rings (cups) [1]
  • one double row inner ring (double cone) [2]
  • two roller and cage assemblies
This option may be advantageous as regards both price and delivery time and should be considered if sealed double row bearings are required, although this will require a non-standard inner ring.
For details about this option, contact the SKF application engineering service.
SKF Explorer bearings
SKF continuously expands its assortment of SKF Explorer bearings. In addition to the existing SKF Explorer single row tapered roller bearings (→ product tables TDO and TDI designs), SKF can also manufacture basic design tapered roller bearings as SKF Explorer bearings, on request. These SKF Explorer tapered roller bearings are identified by the designation suffix PEX.
Variants/features

SKF manufactures TDO and TDI design bearings in many variants and with different features. Bearing-related design variants and features are identified in the product tables (→ product tables TDO and TDI designs) under Design variant/feature. For other sizes, design variants or feature combinations not listed in the product tables, contact SKF. Design variants and features are identified by the following characters within designation suffixes:

Design variants
EExtended inner ring
NWithout intermediate ring
SSteep contact angle α
T
Tapered bore, taper 1:12
.1Steel pin-type cages and pierced rollers
.2Retention sleeve over the outer rings


Features (TDO → fig. 5, TDI → fig. 6)
COuter ring with blind hole
DOuter ring with annular groove and lubrication holes (TDO), inner ring with annular groove and lubrication holes (TDI)
D0Outer ring with annular groove and lubrication holes, without intermediate ring
D2Outer ring with annular groove and lubrication holes, intermediate ring with lubrication holes
D3Outer ring with annular groove and lubrication holes, intermediate ring with annular groove and lubrication holes
GHelical groove in the inner ring bore
NTwo notches at 180° in one side face of the inner ring
N1One notch in each side face of the inner ring, at 180° to notch in opposite side face
N2Two notches at 180° in both side faces of the inner ring, at 90° to notches in opposite side face
TN9
Glass fibre reinforced PA66 cage
VContact seals on both sides
WLubrication grooves in the side faces of the bearing rings
WILubrication grooves in the side faces of the inner ring(s)
WOLubrication grooves in the side faces of the outer ring(s)
XDOuter ring with lubrication holes
YBearing without intermediate ring between the outer rings
Y2Intermediate ring with annular groove and lubrication holes between the outer ring
Z
Sheet steel shield on both sides
Cages

SKF double row tapered roller bearings are fitted with two of the cages shown in table 1. The standard stamped steel cage is not identified in the bearing designation. If non-standard cages are required, check availability prior to ordering.

When used at high temperatures, some lubricants can have a detrimental effect on polyamide cages. For information about the suitability of cages, refer to Cages.

SKF logo