Spur gears are a type of cylindrical gear, with shafts that are parallel and coplanar, and teeth that are straight and oriented parallel to the shafts. They’re arguably the easiest and most common kind of gear 
- easy to manufacture and suitable for an array of applications.
The teeth of a spur gear possess an involute profile and mesh one tooth at the same time. The involute form means that spur gears just generate radial forces (no axial forces), however the approach to tooth meshing causes high pressure on the gear the teeth and high noise planetary gearbox creation. Because of this, spur gears are usually used for lower swiftness applications, although they can be used at nearly every speed.