Designs and variants

SKF support rollers are available without (fig. 1) or with (fig. 2) flange rings. They have a thick-walled outer ring with its running surface crowned as standard. However, support rollers with a cylindrical (flat) running surface are also available (designation suffix X).

Support rollers without flange rings require adjacent components to guide the outer ring and cage axially.

Support rollers with flange rings do not need adjacent components to guide the outer ring and cage axially (fig. 3). Axial loads, which are induced when shafts are not horizontal or aligned properly, are accommodated by the flange rings.

Support rollers without flange rings
  • require adjacent components to guide the outer ring and cage axially
  • are based on needle roller bearings
  • are available:
    • with an inner ring, which is slightly wider than the outer ring to avoid axial clamping of the outer ring
    • without an inner ring (designation prefix R), intended for arrangements where the pin or shaft is hardened and ground

(R)STO design support rollers

  • are available:
    • with an inner ring (fig. 4) that can be mounted separately from the outer ring and roller and cage assembly, which must always be kept together as supplied
    • without an inner ring (prefix R, fig. 5)
    • only open (without seals)

(R)NA 22...2RS design support rollers

  • are available:
    • with an inner ring that can be mounted separately from the outer ring and roller and cage assembly (fig. 6)
    • without an inner ring (prefix R, fig. 7)
    • greased and capped with a sheet steel reinforced NBR contact seal on both sides
  • have the needle roller and cage assembly axially guided between two integral flanges in the outer ring to form a non-separable unit
Support rollers with flange rings
  • do not need adjacent components to guide the outer ring and cage axially (fig. 3)
  • are non-separable units
  • have different flange designs:
    • pressed-on flange rings (NATR and NATV designs)
    • loose flange rings (NUTR, PWTR and NNTR designs)
  • accommode axial loads that can occur due to skew or tilting

NATR and NATV design support rollers

  • are based on:
    • a needle roller and cage assembly (NATR design, fig. 8)
    • a full complement of needle rollers (NATV design, fig. 9)
  • have the outer ring axially guided by pressed-on flange rings, forming a gap-type seal
  • are also available with an axial sliding ring on both sides (designation suffixes PPA and PPXA) (fig. 10):
    • made of PA66
    • forming narrow labyrinth seals with the outer ring in a radial direction, to protect against coarse contaminants
    • serving as contact seals in an axial direction to retain grease reliably in the bearing
    • improving lubrication conditions in the bearing, keeping friction and frictional heat low, and extending grease life

NUTR .. A design support rollers

  • are based on double row full complement cylindrical roller bearings without an integral flange between the two roller sets (fig. 11)
  • have an outer ring with two integral flanges, which guide the roller sets axially
  • have an inner ring with two loose flange rings, which guide the outer ring axially via the roller sets
  • have a sheet metal angle ring pressed into the outer ring shoulder on both sides:
    • forming an effective labyrinth seal
    • extending over the flange rings, making the bearing non-separable
  • accommodate relatively heavy axial loads that can occur due to skew or tilting
  • can be supplied with a reinforced (thicker) outer ring to accommodate heavy impact loads (e.g. NUTR 50 A → NUTR 50110 A)

PWTR ...2RS design support rollers

  • are based on double row full complement cylindrical roller bearings (fig. 12)
  • have an outer ring with three integral flanges, which guide the roller sets axially
  • have an inner ring with two loose flange rings, which guide the outer ring axially via the roller sets
  • have a relatively large grease quantity between the two roller sets
  • are fitted on both sides with an NBR contact seal, being integral with a sheet metal angle ring that is pressed into the outer ring shoulder:
    • to press against the flange rings
    • extending over the flange rings, making the bearing non-separable
  • accommodate relatively heavy axial loads that can occur due to skew or tilting
  • can be supplied with a reinforced (thicker) outer ring to accommodate heavy impact loads (e.g. PWTR 50.2RS → PWTR 50110.2RS)

NNTR ...2ZL design support rollers

  • are based on double row full complement cylindrical roller bearings (fig. 13)
  • have an outer ring with three integral flanges, which guide the roller sets axially
  • have an inner ring with two loose flange rings, which guide the outer ring axially via the roller sets
  • have a relatively large grease quantity between the two roller sets
  • are fitted with a lamellar seal on both sides, inserted into recesses in the shoulders of the flange rings and the outer ring, making the bearing non-separable
  • accommodate very heavy radial loads and relatively heavy axial loads that can occur due to skew or tilting
Cages

SKF support rollers, if not a full complement of rollers, are be fitted with one of the cages shown in table 1. The standard cage is not identified in the bearing designation.

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

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