Pillow block bearing

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Pillow block bearing

Pillow block bearing units are usually a housed bearing with a machined mounting surface  and used in mechanical power transmission systems to support shafts and couplings. The shaft is parallel to the mounting surface and generally perpendicular to the mounting screws. They are a type of housed bearing units. These could have different types of bearings such as ball bearing, cylindrical bearing, tapered roller or synthetic bushing.

Split Pillow block bearing shown with shaft
Split Pillow block bearing shown with shaft (Image credit : FAG)

They are sometimes identified as “Pummel blocks”, although they are marginally different in its construction. It is important to understand the difference between the pillow and pummel block bearing units. While the design is very similar and uses the same types of bearings, They differ in terms of their application. Plummer blocks are used to transfer high power and support heavy industrial loads, while pillow blocks are for lightweight usage. Due to this difference, their construction material and choice of bearing types may also vary.

Types of Pillow block bearings

Pillow block bearings can be classified into two types in terms of housing construction.

Split pillow block bearing

Pillow block bearing
Pillow block bearing

Solid and split housings. Solid housed bearings are single-piece housings, while split housed bearings are two-piece housings

How to select pillow block bearings

  • Select a bearing type, suitable for your application, i.e. Load type, shaft size, running speed, misalignment etc. Pillow block bearings can contain the following types of bearings
    • Plain bearing
    • Ball-bearing
    • Roller bearings – Tapered roller bearing, Spherical- roller bearings, Cylindrical roller bearings,
  • Select the correct housing material for your application and environment
  • Choose a suitable shaft attachment
    • Units can have set screw, eccentric lock, single or double set collar, concentric lock or tapered adapter
  • Consider split type if it’s necessary and if it would make the installation easy
  • For high load applications, choose a pummel block bearing unit with a suitable bearing type
  • Seals vary as well, including clearance seals, light contact, heavy contact and auxiliary type seals

How to Install a Pillow Block Bearing

With careful consideration of selection, proper installation and good maintenance, pillow block bearings can last years without the need to replace them.

This video How to Install a Pillow Block Bearing by Rexnord is worth watching to learn more about the best installation techniques.

Pillow block bearing applications

Pillow block bearing units are very versatile and can be used in a wide variety of applications. It can range from shafts supported by single to several bearings units. For example:

  • Belt drives connecting motors and pumps
  • Long shafts connecting motors and industrial gearboxes
  • Conveyor belt roller
  • Rolling mills
  • Ventilation systems
  • Paper machines

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