An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that acts to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings better support combined loads (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature environments. They also tend to wear in a similar way to bearing steel—rather than cracking or shattering like glass or porcelain.
Most bicycles use angular-contact bearings in the headsets because the forces on these bearings are in both the radial and axial direction.
Keywords
glass
steel
balls
range
loads
forces
headsets
Ceramics
turbines
combined
materials
porcelain
axial load
outer race
inner race
radial load
similar way
low density
jet engines
oblique path
Most bicycles
contact angle
straight line
silicon nitride
asymmetric races
10 to 45 degrees
axial directions
centrifugal force
dentistry equipment
relative proportions
high speed applications
Angular contact bearings
angular-contact bearings
angular contact ball bearing
high temperature environments
