08-17-2017, 12:05 AM
Ceramic Ball Bearing Performance Tests
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A New Ball Bearing
INTRODUCTION:
Want to save a *million barrels of petroleum a day by simply changing to a more
efficient ball bearing in machinery? Sounds too good to be true, but it s possible with
new materials available today.
Tribology The science of friction and wear.
If we look at the surface finish of a metal ball or race very closely, peaks and valleys
appear over these surfaces. It is the job of fluid lubricants to fill- in these valleys with an
incompressible fluid such as oil and grease, to prevent peaks on a ball from contacting
peaks on a race. If contact occurs, the area of contact is so small that a pressure of over 1
million pounds per square inch occurs with a small force on the ball or race. This
pressure causes cold welding between the ball and race which is easily broken by the
inertia of the system but causes heat. This condition, if allowed to repeat itself, causes
failure of the fluid lubricant which heats up further and eventually causes failure of the
bearing.
These concepts when applied to the ceramic ball bearing result in:
1. Longer life.
2. Reduction in energy consumption.
3. Ability to operate in extreme environment and temperatures.
TESTING - Comparison tests were made between several all- metal bearings. They were
tested and compared to a Teflon sealed (non contact) bearing with Teflon retainer,
zirconia race and silicon nitride balls i.e. an all ceramic bearing. The attached photo
shows the test figure which was taken up to 5000 rpm with an external drive which was
disengaged. Time and rpm were recorded with a digital cameral. Bearings tested were
in. I.D x 5/8 in. O.D; ABEC 1. Each bearing was tested using the same apparatus and
procedure.