Spur gears are the most typical kind of gears. They have straight teeth, and are installed on parallel shafts. Occasionally, many spur gears are utilized simultaneously to create large gear reductions.
Spur gears are found in many products that you can see around 
HowStuffWorks, like the electric screwdriver, dancing 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 additional gear, one’s teeth collide, and this Agricultural Gearbox impact makes a sound. In addition, it increases the pressure on the gear teeth.
To reduce the noise and tension in the gears, the majority of the gears in your vehicle are helical.