Spur gears are the most typical type of gears. They have straight teeth, and so are mounted on parallel shafts. Sometimes, many spur gears are Universal joint utilized at once to create large gear reductions.
Spur gears are used in many devices that you could see all over HowStuffWorks, like the electric powered screwdriver, dancing monster, oscillating sprinkler, windup noisy alarms, washer and clothes dryer. But you won’t 
discover many in your car.
This is since the spur gear could be really loud. Each time a gear tooth engages a tooth on the various other gear, the teeth collide, which impact makes a noise. It also increases the stress on the gear teeth.
To lessen the noise and tension in the gears, the majority of the gears in your vehicle are helical.