Spur gears certainly are a type of cylindrical equipment, with shafts that are parallel and coplanar, and tooth that are straight and oriented parallel to the shafts. They’re arguably the simplest and most common type of gear – easy to manufacture and ideal for a wide range of applications.
One’s teeth of a spur gear possess an involute profile and mesh one tooth at the same time. The involute type implies that spur gears just create radial forces (no axial forces), planetary gearbox however 
the approach to tooth meshing causes high stress on the gear the teeth and high noise production. Because of this, spur gears are typically used for lower rate applications, although they can be utilized at nearly every speed.