A comprehensive engineers' reference source for radial ball bearings and thrust ball bearing



              ball bearing overview
              ball bearing bore
              Ball bearing failure
              Ball bearing overview
              Ball bearing bore
              Ball Bearing failure modes
              Ball Bearing Fatigue life
              Ball Bearing Load ratings
              Bearing handling
              Bearing Misalignment
              Ball Bearing Mounting and fitting

              Ball bearing wear


Single-row deep groove ball bearings are the most common type of rolling bearing, having a wide range of suitable applications. The raceway grooves on both inner and outer rings have circular arcs of slightly larger radius than that of the balls. In addition to radial loads, axial loads can be applied in either direction. Because of their low torque, they offer high speed operation with low power loss. Miniature and instrument bearings are made with very high levels of precision, therefore these are generally used in applications where accurate rotational performance and low torque is necessary, and load capacity is a secondary issue.

BEARING NOMENCLATURE (click on link for technical explanation)

Symbol Description
d Ball Bearing bore
D Bearing outer diameter
Df Flange diameter
W Open bearing width
Ws Shielded bearing width
Wi Extended inner race width (open)
Wis Extended inner race width (shielded)
Wf Flange width (open)
Wis Flange width (shielded)
li Land diameter (inner race)
lo Land diameter (outer race)
r Max. mating fillet radius (typical)
H Thrust bearing height
Symbol Description
Dw Ball diameter
N Number of balls per row
Ri Raceway radius (inner race)
Ro Raceway radius (outer race)
fi Raceway curvature ratio (inner race)
fo Raceway curvature ratio (outer race
B Total bearing raceway curvature
r Radial play
a Axial play
Symbol Description
α Ball contact angle
αo Initial ball contact angle
dp Ball pitch diameter
uf Free angle of misalignment
Fr Radial load
Fa Axial or thrust load
d Axial displacement under thrust load
dN Speed factor
fn Lubricant factor
L10 Bearing fatigue life (90% reliability)
Lna Bearing fatigue life after normal adjustments
a1 Material and reliability life correction factor
a2 Operating conditions life correction factor
P Equivalent load
Pr Equivalent radial load
Pa Equivalent axial load
C Dynamic radial load rating
Ct C derated for higher temperature
Co Static radial load rating
Cs Static axial load rating
ft Temperature correction factor
fp Interference factor

American Bearing Manufacturers Association (ABMA)

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