Spur gears are the most commonly used type of gears. The teeth are located in radial planes, the contact line of the teeth of the pair of gears is parallel to the axis of rotation, and the axes of both gears (gears) are strictly parallel.
Spur gears are the most commonly used and are among the first gears invented. The prototypes of spur gears appeared thousands of years ago. Now, spur gears are made of different materials, metal, plastic, and composite parts are also made using combinations of different metals and plastics. Spur gears allow the transmission of the translational moment only to the shafts that are in the same plane (parallel).