Spur gears have teeth that are ________.

Spur gears have teeth that are ________.

• A. Curved
• B. Straight
• C. Herringboned
• D. Beveled

Answer: (B)

Spur gears are defined by teeth that are straight and run parallel to the gear’s axis. This straight-tooth arrangement lets the gears mesh in a single, simple plane when the shafts are parallel, making them easy and inexpensive to manufacture and assemble. Because the contact is a straight line along the pitch, spur gears transmit power efficiently between parallel shafts, with minimal axial thrust. The trade-off is that they can be noisier at higher speeds. Curved or angled teeth belong to gears like helical or herringbone types, which are designed for nonparallel shafts or different load paths. Beveled gears have teeth cut on a conical surface for changing shaft directions. So the straight, parallel-to-axis teeth describe spur gears exactly.

Spur gears are defined by teeth that are straight and run parallel to the gear’s axis. This straight-tooth arrangement lets the gears mesh in a single, simple plane when the shafts are parallel, making them easy and inexpensive to manufacture and assemble. Because the contact is a straight line along the pitch, spur gears transmit power efficiently between parallel shafts, with minimal axial thrust. The trade-off is that they can be noisier at higher speeds.

Curved or angled teeth belong to gears like helical or herringbone types, which are designed for nonparallel shafts or different load paths. Beveled gears have teeth cut on a conical surface for changing shaft directions. So the straight, parallel-to-axis teeth describe spur gears exactly.