Spur gears certainly are a type of cylindrical gear, with shafts that are parallel and coplanar, and the teeth that are directly and oriented parallel to the shafts. They’re arguably the planetary gearbox simplest and most common type of gear – easy to manufacture and ideal for an array of applications.

The teeth of a spur gear have an involute profile and mesh one tooth at a time. The involute type means that spur gears just produce radial forces (no axial forces), however the approach to tooth meshing causes high stress on the gear tooth and high noise production. For this reason, spur gears are usually used for lower swiftness applications, although they can be utilized at nearly every speed.