Which gear type is used to change the direction of rotation between shafts that meet at an angle?

• A. Spur Gears
• B. Helical Gears
• C. Bevel Gears
• D. Rack and Pinion.

Answer: (C)

Bevel gears are used to change the direction of rotation between shafts that meet at an angle. Their teeth are cut on a conical surface, so as two bevel gears mesh, the axes intersect and the rotation can be redirected from one shaft to the other—commonly at 90 degrees, though different angles are possible with various bevel types. This makes them the standard choice when the mechanical layout requires crossing shafts. By contrast, spur gears are for parallel shafts and mainly transfer motion along a line; helical gears also suit parallel or nonintersecting arrangements and don’t specifically address intersecting axes, and rack and pinion converts rotational motion to linear motion rather than changing the axis direction.