The calculated rating life of a rolling contact bearing varies as a function of___________________?
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Answer: C. inversely as cube of load
Explanation
Rolling contact bearing fatigue life is governed by empirical load rating equations. The calculated rating life varies inversely as the cube of the applied dynamic load. Doubling the applied load reduces the expected bearing fatigue life by a factor of eight. Bearing life is defined as the total number of revolutions before initial fatigue spalling occurs. L10 life represents the operating hours that ninety percent of a bearing group will achieve. Subsurface shear stresses caused by rolling elements dictate the eventual fatigue failure limit.
Engineers select rolling bearings by calculating expected loads to ensure adequate operational lifespans. Overloading industrial gearboxes drastically shortens bearing life due to the cubic load relationship. Proper lubrication and cleanliness help bearings achieve or exceed their calculated rating life. Rating life does not vary directly with load because higher loads accelerate fatigue exponentially. Inverse square relationships underestimate the aggressive impact of increased loads on fatigue life. The fourth power applies specifically to certain sliding wear conditions rather than standard rolling bearings.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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