Which of the following represents an example of a rolling pair________________?
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Answer: D. ball bearing and roller bearing
Explanation
Ball bearings and roller bearings incorporate rolling elements that move across raceways. This rolling action replaces sliding friction with rolling friction to improve mechanical efficiency. The contact between the rolling elements and races classifies these assemblies as rolling pairs. Rolling pairs occur when two machine elements roll over each other without significant sliding. Antifriction bearings significantly reduce rotational resistance in high-speed machinery shafts. Rolling contact mechanisms require high-hardness steels to resist cyclic contact fatigue stresses.
Electric motors, automobile wheels, and industrial turbines rely on rolling bearings for support. Minimizing friction through rolling pairs saves energy and reduces heat generation in machinery. Proper lubrication is still necessary in rolling bearings to prevent micro-sliding and surface wear. Option A involves screw and sliding contact, representing lower pairs rather than rolling pairs. Option B utilizes threaded lead screws which feature sliding helical motion. Option C features ball and socket joints which provide spherical turning lower pair motion.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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