Designs and variants

Insert bearings (SKF Y-bearings) typically have a sphered (convex) outside surface and an extended inner ring (fig. 1) with different locking devices. The various Insert bearing series differ in the way the bearing is locked onto the shaft:
  • with grub (set) screws (fig. 2)
  • with an eccentric locking collar (fig. 3)
  • with SKF ConCentra locking technology (fig. 4)
  • with an adapter sleeve (fig. 5)
  • with an interference fit (fig. 6)
Insert bearings with an inner ring that is extended on both sides run more smoothly, as the extent to which the inner ring can tilt on the shaft is reduced.
The standard SKF insert bearing assortment described hereafter includes also application-specific variants such as:
  • bearings made of stainless steel or with zinc-coated rings for the food industry (→ Insert bearings with grub screws)
  • bearings for agricultural applications
Insert bearings with grub screws
  • are suitable for applications for both constant and alternating direction of rotation
  • are locked onto the shaft by tightening the two cup point hexagonal grub (set) screws, positioned 120° apart in the inner ring

Basic design bearings

  • are available for metric shafts ranging from 12 to 100 mm and for inch shafts from 1/2 to 3 inches
  • are available with an inner ring extended on one side (fig. 7, bearing series YAT 2)
  • are available with an inner ring extended on both sides (fig. 8, bearing series YAR 2)
  • are capped on both sides (→ Sealing solutions) with:
    • a rugged standard seal (→ Standard seals) for bearing series YAT 2
    • a rugged standard seal and an additional plain sheet steel flinger (→ Standard seals with additional flingers, designation suffix 2F) or a rubberized sheet steel flinger (→ Multiple seals, designation suffix 2RF) for bearing series YAR 2
  • have two lubrication holes in the outer ring as standard, one on each side, positioned 120° apart
  • can be supplied without lubrication holes on request (designation suffix W)
For demanding operating conditions that occur in agricultural applications such as combines and balers, harvesters and disk harrows, SKF has designed the YARAG 2 bearings series (fig. 9). These bearings are:
  • available for metric shafts ranging from 20 to 50 mm and for inch shafts from 1 to 1 15/16 inches
  • fitted with a patented 5-lip seal (→ Sealing solutions, 5-lip seals)
  • supplied without any lubrication holes in the outer ring

Bearings with zinc-coated rings

  • are available for metric shafts ranging from 20 to 50 mm and for inch shafts from 3/4 to 1 15/16 inches for use in corrosive environments
  • are available with an inner ring extended on both sides (bearing series YAR 2..-2RF/VE495)
  • have the grub screws made of stainless steel
  • are capped on both sides with a highly effective multiple seal (→ Sealing solutions, Multiple seals) made of food-compatible rubber with a stainless steel insert and a stainless steel flinger
  • are filled with a food-grade grease
  • have two lubrication holes in the outer ring, positioned 120° apart, one on each side

Stainless steel bearings

  • are available for metric shafts ranging from 20 to 50 mm and for inch shafts from 3/4 to 1 15/16 inches for use in corrosive environments
  • are available with an inner ring extended on both sides (bearing series YAR 2..-2RF/HV)
  • have all steel components made of stainless steel, including rings, balls, sheet metal parts of both seals and flingers, and grub screws
  • are capped on both sides with a highly effective multiple seal (→ Sealing solutions, Multiple seals) made of food-compatible rubber with a stainless steel insert and a stainless steel flinger
  • are filled with a food-grade grease
  • have an annular groove with one lubrication hole in the outer ring, located on the side opposite the locking device
  • have a lower dynamic load carrying capacity than same-sized bearings made of high grade carbon chromium steel
Insert bearings with an eccentric locking collar
  • are available for metric shafts ranging from 15 to 60 mm and for inch shafts from 1/2 to 2 7/16 inches
  • are intended primarily for use in applications where the direction of rotation is constant
  • have at the extended inner ring on one side an eccentric step to accommodates the locking collar, which is:
    • zinc-coated for bearings with a metric bore
    • black-oxidized for bearings with an inch bore
  • are locked onto the shaft by turning the locking collar in the direction of rotation; a single grub screw further secures the collar to the shaft
  • are available with an inner ring extended on one side (fig. 10, bearing series YET 2)
  • are available with an inner ring extended on both sides (fig. 11, bearing series YEL 2)
  • are capped on both sides (→ Sealing solutions) with:
    • a rugged standard seal (→ Standard seals) for bearing series YET 2
    • a rugged standard seal and an additional plain sheet steel flinger (→ Standard seals with additional flingers, designation suffix 2F) or a rubberized sheet steel flinger (→ Multiple seals, designation suffix 2RF/VL065) for bearing series YEL 2
  • have two lubrication holes in the outer ring as standard, one on each side, positioned 120° apart
  • can be supplied without lubrication holes on request (designation suffix W)
For demanding operating conditions that occur in agricultural applications such as combines and balers, harvesters and disk harrows, SKF has designed the YELAG 2 bearings series (fig. 12). These bearings are:
  • available for metric shafts ranging from 20 to 50 mm and for inch shafts from 1 to 1 15/16 inches
  • fitted with a patented 5-lip seal (→ Sealing solutions, 5-lip seals)
  • supplied without any lubrication holes in the outer ring
SKF ConCentra insert bearings
  • are available for metric shafts ranging from 25 to 60 mm and for inch shafts from 1 to 2 11/16 inches
  • can be used in applications for both constant and alternating direction of rotation
  • provide an easy, quick and reliable way to lock a bearing onto a shaft, even in applications where there are heavy loads and/or high speeds
  • permit the full limiting speed to be achieved, even where using commercial grade shafts
  • have an inner ring symmetrically extended on both sides (fig. 13, bearing series YSP 2)
  • comprise the patented SKF ConCentra locking technology, which is based on the expansion and contraction of two mating surfaces, which have precision-engineered serrations:
    • the bearing bore
    • the external surface of the stepped sleeve
  • provide a true concentric fit on the shaft, because when the grub screws in the mounting collar are tightened, the inner ring is axially displaced relative to the stepped sleeve (fig. 14 and fig. 15), forcing the bearing inner ring to expand and the stepped sleeve to contract evenly
  • provide low noise and vibration levels and virtually eliminate fretting corrosion
  • are capped on both sides with a rugged standard seal and an additional plain sheet steel flinger (→ Sealing solutions, Standard seals with additional flingers)
  • have two lubrication holes in the outer ring as standard, one on each side, positioned 120° apart
  • can be supplied without lubrication holes on request (designation suffix W)
For demanding operating conditions that occur in agricultural applications such as combines and balers, harvesters and disk harrows, SKF has designed the YSPAG 2 bearings series (fig. 16). These bearings are:
  • available for metric shafts ranging from 20 to 50 mm and for inch shafts from 1 to 1 15/16 inches
  • fitted with a patented 5-lip seal (→ Sealing solutions, 5-lip seals)
  • supplied without any lubrication holes in the outer ring
Insert bearings with a tapered bore
  • are available with bore diameters ranging from 25 to 65 mm, which fit the following adapter sleeves:
    • H 23 series for metric shafts ranging from 20 to 60 mm
    • HA 23 and HE 23 series for inch shafts ranging from 3/4 to 2 11/16 inches
  • can be used in applications for both constant and alternating direction of rotation
  • permit the full limiting speed to be achieved where mounted on an adapter sleeve, even where using commercial grade shafts
  • have an inner ring symmetrically extended on both sides and a tapered bore (taper 1:12) (fig. 17, bearing series YSA 2)
  • are capped on both sides with a rugged standard seal and an additional plain sheet steel flinger (→ Sealing solutions, Standard seals with additional flingers)
  • have two lubrication holes in the outer ring as standard, one on each side, positioned 120° apart
  • can be supplied without lubrication holes on request (designation suffix W)
The associated adapter sleeves must be ordered separately from the bearings.
Insert bearings with a standard inner ring
  • are available for metric shafts ranging from 17 to 60 mm
  • are suitable for applications where the direction of the load alternates and where smooth running is a key operational parameter
  • have normal tolerances for the bearing bore diameter and are locked onto the shaft using an appropriate interference fit
  • have the same dimensions and features as deep groove ball bearings in the 62 and 63 series, but have a sphered (convex) outside surface (fig. 18, bearing series 17262 and 17263)
  • accommodate heavier axial loads than any other insert bearings
  • can operate at the same speeds as a corresponding sealed deep groove ball bearing
  • are capped on both sides (→ Sealing solutions) with:
    • an NBR contact seal (→ RS1 seals, designation suffix 2FRS1) as standard
    • a rugged standard seal (→ Standard seals, designation suffix 2FRS1/VP274)
  • do not have any lubrication holes in the outer ring as standard
  • can be supplied with two lubrication holes in the outer ring, one on each side, positioned 120° apart (designation suffix B)
Sealing solutions

SKF supplies all insert bearings capped with a seal or shield on both sides. In typical insert bearing applications, no additional external protection is necessary. Therefore, insert bearings are available with several sealing arrangement designs to meet the demands of a wide range of operating conditions.

When capped bearings must operate under certain conditions, such as very high speeds or high temperatures, grease may appear between the inner ring and capping device. For bearing arrangements where this would be detrimental, appropriate actions should be taken.

Standard seals

  • consist of a stamped sheet steel washer with a seal lip made of NBR, vulcanized to its inner surface (fig. 19, designation suffix VP274 for bearings with a standard inner ring and no designation suffix for other insert bearings)
  • form with its non-contact sheet steel washer a narrow gap with the inner ring shoulder to protect the seal against coarse contaminants

Standard seals with additional flingers

  • are recommended for more contaminated environments
  • consist of a a standard seal and an additional sheet steel or stainless sheet steel plain flinger  (fig. 20, designation suffix 2F)
  • have an interference fit of the flinger on the inner ring shoulder to considerably improve the effectiveness of the seal without increasing friction
  • are only available for bearings with an inner ring extended on both sides

Multiple seals

  • are recommended for very contaminated environments
  • consist of a standard seal and a flinger with a vulcanized NBR lip, which seals axially against the standard seal (fig. 21, designation suffix 2RF)
  • have the space between the flinger lip and the inner ring shoulder filled with grease to provide additional protection
  • are only available for bearings with an inner ring extended on both sides

5-lip seals

  • are recommended for extremely contaminated environments, such as agricultural applications
  • are patented by SKF
  • consist of a sheet steel insert with a vulcanized 5-lip contact seal made of a low-friction NBR compound (fig. 22):
    • The steel insert is held in place by a groove in the bearing outer ring and protects the seal from solid contaminants.
    • Each seal lip has a different design to provide superior sealing performance in response to different operating conditions, including dynamic misalignment.
    • The outermost and innermost lips act as a labyrinth to prevent contaminant ingress and grease leakage respectively.
    • The three inner lips make constant contact with the inner ring shoulder.
  • are only available for bearings with an inner ring extended on both sides

RS1 seals

  • have been developed for standard SKF deep groove ball bearings
  • are fitted in a recess on the outer ring and ride against the inner ring shoulder to act as contact seals (fig. 23, designation suffix 2RS1)
  • are made of sheet steel reinforced NBR

Shields

  • are designed for applications where the contamination level is low and additional friction should be avoided
  • are fitted in a recess on the outer ring (fig. 24, designation suffix VP076)
  • do not make contact with the inner ring, but form a narrow gap
  • are made of sheet steel
  • are only available for insert bearings on request

Bearings with shields should not be used if water, steam or moisture can enter the bearing.

Cages

SKF insert bearings are fitted as standard with a snap- type, glass fibre reinforced PA66 cage (fig. 25), no designation suffix.

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.

Rubber seating rings
  • are available in the RIS 2 series (fig. 26, product table)
  • can be fitted on all SKF insert bearings, except for those with a standard inner ring (17262 and 17263 series)
  • are primarily intended to “cushion” insert bearings in pressed steel plummer block housings
  • are intended to dampen vibration and noise
  • are intended to enable the bearings to be displaced slightly in their housings to accommodate minor shaft expansion or misalignment
  • are located on the bearing outer ring and in housing bore (fig. 27)
  • have a sphered (convex) outside surface
  • are made of NBR
  • can withstand temperatures ranging from –30 to +100 °C (–20 to +210 °F).
 

Rubber seating rings are available as an accessory and must be ordered separately. However, insert bearings in the YET 2 series can be supplied with the seating ring already fitted (fig. 28). These products are identified by the series prefix CYS, followed by the bearing bore diameter and the bearing identification suffix FM. E.g. CYS 20 FM is a YET 204 bearing with a 20 mm bore, fitted with an RIS 204 rubber seating ring.

SKF logo