In a standard V-belt transmission, the belt makes physical contact with______________?
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Answer: B. at sides only
Explanation
Standard V-belts transmit torque through wedging action by making physical contact exclusively along their sloping sides. The bottom of the belt must remain completely clear to prevent destructive friction against the sheave groove base. Wedge action significantly increases the normal force between the belt and pulley surfaces to improve power transmission efficiency. V-belts are flexible power transmission elements featuring a trapezoidal cross-section designed to fit matching pulley grooves. The wedging phenomenon multiplies the effective frictional grip without requiring excessive initial tension in the belt drive assembly. Pulley grooves are engineered with slightly narrower angles than the belt cross-section to guarantee side wall engagement.
Option A is incorrect because bottom contact decreases overall transmission efficiency and causes rapid premature mechanical wear. Option C is physically impossible since the sheave and belt dimensions are engineered to eliminate any base interference. Option D is wrong because contact is strictly localized to the inclined side walls of the matching V-groove.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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