Speed Limit and
Maximum Acceleration
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4.1
Speed Limit
The
limiting speed of rolling element bearings is primarily a function of
size and internal design. The speed limits given in this catalog should
not be exceeded on a continuous basis to prevent premature failure due
to excessive temperature. Contact RBC for solutions to high speed applications.
4.2
Maximum Acceleration (Deceleration)
A sufficiently
large tangential friction force Ft , acting between outside diameter
and track is needed to change the rotational speed of cam follower and
yoke roller outer rings.
where
u = coefficient of friction (outer ring to track) |
(10) |
The
force Ft produces a moment Mt, which must accelerate the masses of outer
ring and rollers around the bearing axis, plus the rollers in the load
zone around their own axes.
The
movement Mt can be calculated using:
|
(11) |
Accelerating
the mass of the outer ring normally requires the largest part of moment
Mt. Assuming a coefficient of friction of m = 0.10 and a typical cam
follower design, the following equation may be used for an estimate
of the permissible angular acceleration a:
|
(12) |
Excessive
acceleration causes sliding of the outer ring on the track. The effects
range from minor uniform wear on cam follower and track to flat spots
on the cam follower with subsequent failure.
|
