Other SKF Rolling Bearings

SKF produces many other bearings, most of which are intended for specific applications. These include precision bearings for machine tools and similar applications, see the catalogue “High-precision bearings”, as well as individually tailored bearings. For example, the bearings for automotive applications are generally specific to a given car model and often include additional features thus reducing the number of individual components required for an application. Linear ball bearings also form part of the SKF range and are covered by separate printed catalogues and electronically via “SKF Linear Motion”.

High-/super-precision bearings

See catalogue “High-/super-precision bearings”.

Fixed section bearings

Fixed section bearings form one group of thin section bearings. Another group comprises bearings of the light Dimension Series 18, 19 and 10 to ISO 15:1998. As the name suggests, thin section bearings have very thin rings and very small cross section. They are further characterized by low weight, low friction and high stiffness. These characteristics make them particularly suitable for compact, lightweight bearing arrangements which are stiff and which have relatively large bore diameters. Thin section bearings are therefore preferred for industrial robots, textile machinery, printing presses, machine tool turntables, radar antennae as well as optical and medical equipment applications.

Fixed section bearings are bearings with inch dimensions and have a constant cross section within a particular series irrespective of bearing size. SKF fixed section bearings are available as

• deep groove ball bearings (fig 1),
• angular contact ball bearings (fig 2) and
• four-point contact ball bearings (fig 3)

in six different square cross sections A, B, C, D, F and G to the “Dimension plan for fixed section bearings”, see table 1. In addition there is one sealed series U for deep groove and four-point contact ball bearings with seals at both sides. The height of the bearing cross section of the U series is the same as the C series but the bearings are wider in order to accommodate the contact seals.

The dimensions of fixed section bearings are not formally standardized but nevertheless they are generally accepted so that interchangeability is assured.

Further information on SKF fixed section bearings will be supplied on request.

Slewing bearings

Slewing bearings (fig 1) are ball or cylindrical roller bearings which can accommodate axial, radial and moment loads acting either singly or in combination and in any direction. They are not mounted on a shaft and in a housing; the rings, which are simply bolted on the seat surface are available in one of three executions

• without gears
• with an internal gear
• with an external gear.

Slewing bearings can perform both oscillating (slewing) movements as well as rotating movements.

The outside diameter range of SKF slewing bearings with a one-piece ring is from 400 to 7 200 mm. Even larger bearings are produced with outside diameters up to 14 000 mm, but these have segmented rings. Some of the smaller sizes, up to approximately 2 000 mm outside diameter are standard production.

Single row slewing ball bearings

SKF single row slewing ball bearings are four-point contact ball bearings (fig 2). The balls are inserted through a filling slot which is plugged afterwards. The bearings are sealed, have no preload and are intended for applications where demands regarding accuracy are moderate.

Single row slewing roller bearings

SKF single row slewing roller bearings are crossed cylindrical roller bearings. (fig 3). Every second roller is at right angles to its neighbouring rollers. The rollers are inserted through a filling slot which is plugged afterwards. The bearings are under preload and have integral lip seals.

Double row slewing bearings

These slewing rings are angular contact cylindrical roller bearings (fig 4). The rollers are inserted through filling slots in one of the rings; the slots are plugged afterwards. Plastic separators provide optimum roller guidance. The bearings are normally preloaded and are fitted with integral lip seals.

Triple row slewing bearings

Triple row slewing bearings are combined radial and thrust cylindrical roller bearings for very heavy loads with one one-piece and one two-piece ring (fig 5). The bearings are not under preload and have integral lip seals. These bearings place high demands on the seat surfaces.

Other slewing bearings

In addition to the standard designs outlined above, SKF also produces several other designs for a multitude of applications to order. These include

• slewing bearings as combined cylindrical roller/ball bearings (fig 6)
• slewing bearings as double row angular contact ball bearings
• dry sliding slewing bearings
• slewing bearings with integral drive (fig 7).

Triple ring bearings

Triple ring bearings are used almost exclusively in papermaking machines for the support of variable crowned press rolls at the drive side. SKF produces three different types inner/outer bearing combinations

• cylindrical/spherical roller bearing (fig 1)
• spherical/cylindrical roller bearing (fig 2)
• spherical/spherical roller bearing (fig 3).

Additional information can be found in the SKF catalogue “Large bearings”.

Multi-row radial ball bearings

For the support of the axially oscillating doctor rolls of papermaking machine dryer sections, SKF produces multi-row radial ball bearings of special design (fig 1). These bearings have several rows of balls held and guided in a machined brass cage. The inner and outer ring raceways have a cylindrical form (fig 2) so that axial displacements of the shaft relative to the housing can be accommodated within the bearing in both directions. Thrust washers are required at both sides of the bearing to limit axial movement of the cage.

Eight standard sizes of varying designs are produced as standard, see table 1.

Bearings for automotive applications

SKF supplies a wide variety of standard and special bearings, (fig 1) including sensorized bearings as well as ready-to-mount bearing units, to the automotive industry for different car and truck applications. The range includes

• car hub units (fig 2)
• truck hub units (fig 3)
• belt tensioner units (fig 4)
• water pump spindles (fig 5)
• clutch release bearings (fig 6)
• propeller shaft intermediate and support bearings (fig 7)
• propeller shaft centring bearings (fig 8)
• suspension bearings (fig 9)
• free wheels (sprag clutches) (fig 10)

Vehicle replacement parts

A comprehensive range of so-called Vehicle Kits is also available for replacement purposes for a wide selection of various car and truck models. These kits contain not only the requisite bearings, but also the appropriate accessories such as seals, nuts, retaining rings etc. The range of kits includes

• hub bearing kits for cars
• hub bearing kits for trucks
• synchronous drive and belt tensioner kits
• clutch release bearing kits for cars
• clutch release bearing kits for trucks
• water pump spindle kits
• suspension bearing kits

For more information about automotive aftermarket products, please visit the SKF website “vsm.skf.com”.

Bearings for railway applications

Bearings are used for a wide variety of purposes in all kind of railway vehicles. They are key components in axleboxes and drive systems such as traction motors and suspension units. Other applications include gearboxes, shock absorbers, tilting mechanisms, doors etc. The latest development involves sensors to detect speed, direction of rotation, bearing condition and bogie stability. These are now becoming standard equipment for several modern train designs. Some product examples are:

• compact tapered roller bearing units with metric or inch dimensions (fig 1),
• axleboxes designed for overall economy, reliability and comfort (fig 2),
• axlebridges for low floor tramcars supporting the two independent wheels fitted with tapered bearing units (fig 3).

For more information, please visit “railways.skf.com”.

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