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

 


Dynaroll
  BALL CONTACT ANGLE  

Contact angle is the angle between a plane perpendicular to the bearing axis and a line joining the two contact points between the ball and the inner and outer raceways. The initial contact angle ao is defined as the contact angle when the bearing is subjected to a minimal axial load to remove the looseness resulting from radial play. The higher the radial play the higher ao. Further axial load will increase the contact angle see section on preload.


FORMULAE FOR INTIAL CONTACT ANGLE ao:



INITIAL CONTACT ANGLE CHART ao DEGREES (fi = fo = 0.56)
BALL DIAMETER (Dw) DYNAROLL RADIAL PLAY CODE [ dimensions in inches (mm) ]
MC2
(.0001 - .0003)
(.003 - .008)
MC3
(.0002 - .0004)
(.005 - .010)
MC4
(.0003 - .0005)
(.008 - .013)
MC5
(.0005 - .0008)
(.013 - .020)
.0236 & 0.6mm 15.1o 18.6o 21.5o 27.5o
.0315 & 0.8mm 13.3o 16.3o 18.9o 24.1o
.0394 & 1.0mm 11.9o 14.5o 16.8 21.5o
.0472 & 1.2mm 10.8o 13.2o 15.3o 19.5o
.0625 (1/16th) 9.3o 11.4o 13.2o 16.9o
.0787 & 2.0mm 8.3o 10.2o 11.8o 15.0o
.0937 (3/32nd) 7.6o 9.4o 10.8o 13.8o
.1250 (1/8th) 6.6o 8.1o 9.4o 11.9o
.1406 (9/64th) 6.2o 7.6o 8.8o 11.2o
.1562 (5/32nd) 5.9o 7.3o 8.4o 10.7o
Note: The above contact angles are given for the mean radial play of the range, i.e. for MC3 (.0002 to .0004 inch), ao initial contact angle is for .0003 inch radial play. Use formula to calculate other exact values.



GRAPH OF ao Vs RADIAL PLAY FOR DIFFERENT BALL SIZES (fi = fo = 0.56)


35o 
30o 
25o 
20o 
15o 
10o 
5o 
BALL SIZE  Inches (mm)
 .0236
(.600)
 .0315
(.800)
 .0394
(1.000)
 .0472
(1.200)
 1/16
(1.588)
 .0787
(2.000)
 .0937
(2.381)
 1/8 
(3.175)
 9/64
(3.572)
 .1575
(4.000)
  0.0002
(.005)
0.0003
(.0075)
0.0004
(.01)
0.0005
(.0125)
0.0006
(.015)
0.0007
(.0175)
0.0008
(.02)
RADIAL PLAY Inches (mm)






Bearing Overview || Materials || Cages and Retainers || Shields and Seals || Bearing Geometry || Abec Tolerance
Lubrication || Load Rating and Lifetime || Bearing Failure || Noise || Torque || Mounting and Fitting
Preload || Bearing Handling || Adhesive Practices || Assembly Characteristics || Specify a Bearing || News

Dynaroll Copyright 2005