Question

Worm gearsets are used for transmitting rotary motion between

• A. non-parallel and non-intersecting shafts
• B. intersecting shafts
• C. parallel shafts
• D. non-parallel and intersecting shafts

Hint:

Think about the relative angle between the two shaft axes and whether they actually cross in space.

Answer 1

The Correct Option is A

Different gear types suit different relative shaft geometries: spur and helical gears for parallel shafts, bevel gears for intersecting shafts, and worm gears for shafts that are neither parallel nor intersecting.

1. Non-parallel and non-intersecting shafts: correct. A worm and a worm wheel sit on perpendicular axes that never meet in space, exactly this case, and worm gearing is the standard choice for it.
2. Intersecting shafts: wrong, that geometry calls for bevel gears, not worm gears.
3. Parallel shafts: wrong, parallel shaft drives use spur or helical gears, where a worm's screw thread action would not mesh properly.
4. Non-parallel and intersecting shafts: wrong, the defining feature of a worm set is that the shafts do not intersect at all, so this mixed description does not fit.

So worm gearsets connect non-parallel and non-intersecting shafts, option A.