Spur gears are the most typical type of gears. They have V Belt Pulley straight teeth, and so are installed on parallel shafts. Occasionally, many spur gears are used at once to create large gear reductions.
Spur gears are found in many products that you could see around HowStuffWorks, like the electric screwdriver, dance monster, oscillating sprinkler, windup alarm clock, washer and clothes dryer. Nevertheless, you won’t discover many in your vehicle.
This is because the spur gear can be really loud. Each time a equipment tooth engages a tooth on the other gear, the teeth collide, which impact makes a sound. In addition, it increases the stress on the gear teeth.
To lessen the noise and stress in the gears, most 
of the gears in your vehicle are helical.