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Terminology

Some frequently used bearing terms are explained here. For a detailed collection of bearing-specific terms and definitions, refer to ISO 5593:1997 Rolling bearings – Vocabulary1).
Symbols

Symbols used in this catalogue are mainly in accordance with ISO standards. Most common symbols for bearing boundary dimensions are shown in fig. 1 and fig. 2. Other symbols are listed below. All symbols can be used with a subscript to identify specifications.

A = speed factor [mm/min]
      = n dm
C = bearing load rating [kN]
dm = bearing mean diameter [mm]
        = 0,5 (d + D)
F = actual bearing load [kN]
L = life, typically in million revolutions or operating hours
n = rotational speed [r/min]
P = equivalent bearing load [kN]
Pu = fatigue load limit [kN]
ηc = factor for contamination level
κ = viscosity ratio: actual versus required
ν = oil viscosity [mm2/s]
Bearing-shaft-housing systems (fig. 3)
  1. Cylindrical roller bearing
  2. Four-point contact ball bearing
  3. Housing
  4. Shaft
  5. Shaft abutment shoulder
  6. Shaft diameter
  7. Shaft seat
  8. End plate
  9. Radial shaft seal
  10. Distance ring
  11. Housing bore diameter
  12. Housing seat
  13. Housing cover
  14. Snap ring
Radial bearings (fig. 4 and fig. 5)
  1. Inner ring
  2. Outer ring
  3. Rolling element: ball, cylindrical roller, needle roller, tapered roller, spherical roller, toroidal roller
  4. Cage
  5. Capping device
    Seal – made of elastomer
    Shield – made of sheet steel
  6. Outer ring outside surface
  7. Inner ring bore
  8. Inner ring shoulder surface
  9. Outer ring shoulder surface
  10. Snap ring groove
  11. Snap ring
  12. Outer ring side face
  13. Recess for capping device
  14. Outer ring raceway
  15. Inner ring raceway
  16. Recess for capping device
  17. Inner ring side face
  18. Chamfer
  19. Bearing pitch circle diameter
  20. Total bearing width
  21. Guide flange
  22. Retaining flange
  23. Contact angle

Thrust bearings (fig. 6)
  1. Shaft washer
  2. Rolling element and cage assembly
  3. Housing washer
  4. Housing washer with a sphered seat surface
  5. Seat washer
  1. 1)For details on how to obtain ISO 5593:1997 Rolling bearings – Vocabulary, refer to ISO 5593:1997.
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