Bearing

#540 / Mechanical Engineering Easy

Consider a roller bearing is selected for a unique assembly. If the design requires a radial load of 2 N and a design life of 3, what is the minimum basic load rating (N)?

Expand Hint
The minimum required basic load rating (the load in which 90% of bearings from a given lot will survive 1 million revolutions) is:
$$$C=PL^{1/a}$$$
where $$C$$ is the minimum required basic load rating, $$P$$ is the design radial load, $$L$$ is the design life (in millions of revolutions), and $$a$$ is the bearing coefficient.
Hint 2
For ball bearings: $$a=3$$
For roller bearings: $$a=\frac{10}{3}$$
The minimum required basic load rating (the load in which 90% of bearings from a given lot will survive 1 million revolutions) is:
$$$C=PL^{1/a}$$$
where $$C$$ is the minimum required basic load rating, $$P$$ is the design radial load, $$L$$ is the design life (in millions of revolutions), and $$a$$ is the bearing coefficient. For ball bearings, $$a=3$$ . However, the problem statement is asking for a roller bearing, so $$a=10/3$$ . Thus,
$$$C=(2N)(3\cdot 10^6)^{1/(10/3)}=(2N)(3,000,000)^{3/10}$$$
$$$=(2N)(87.728)=175.5\:N$$$
175.5 N


☕️ Donate to keep your study guide and instructor running!
🚨 [Beta] Test your FE exam readiness with a timed quiz!
☝️ Take the survey to help us improve!

< Prev #539

random #

#541 Next >