Spur gears are a type of cylindrical gear, with shafts that are parallel and coplanar, and teeth that are directly and oriented parallel to the shafts. They’re arguably the easiest and most common kind of gear – easy to manufacture and ideal for a wide selection of applications.
The teeth of a spur gear possess an planetary gearbox involute profile and mesh one tooth at a time. The involute form means that spur gears only create radial forces (no axial forces), however the method of tooth meshing causes high stress on the gear teeth and high noise production. Due to this, spur gears are usually used for lower velocity applications, although they can be utilized at nearly every speed.