A gear wheel is one with teeth or notches machined into its perimeter. The gear wheel is capable of meshing with the teeth of another gear wheel to create a basic machine. Transmissions, watches and many other types of machines that operate with the help of gears and mechanical drive assemblies all use gear wheels.
When one gear wheel meshes with another it creates a machine capable of increasing or decreasing its mechanical power. This ability to change is known as a gear ratio. The ratio defines the amount of mechanical power or multiplication created by the two gears. The ratio is derived from the gears on each gear wheel.
When one gear turns four complete revolutions while the other meshed gear only turns one revolution, it is said to have a 4:1 gear ratio. When discussing automobile drive axle gear ratios, if the drive shaft turns the pinion gear four complete revolutions and the ring gear turns the tires 10 complete revolutions it is said to have a 4:10 gear ratio.
Gear wheels have helped the world to advance by assisting in ability to create. The strength of a single person can be increased to the strength of hundreds of with the proper gear ratio of a machine utilizing gear wheels. The gear wheel allows machines to perform and accomplish tasks that would not be possible by using the singular strength of people or even horses.
The gear wheel also allows a machine to produce high-speed functions with a low-speed input by the use of gear ratio multiplication. By choosing the properly sized gears, a slow input speed can be converted to a high output speed and the user can enjoy the benefits of a powerful fan by cranking a handle very slow.
An automobile transmission is a prime example of gear multiplication. As an automobile operates, the engine remains in a fairly common revolution per minute (RPM) level. To increase speed, the transmission gear wheel system begins to change gear combinations or shifts gears and the vehicle's speed increases. The transmission continues to change the order in which the different sets of gear wheel combinations interlock and the vehicle shifts through all of the possible gear changes to reach a cruising speed.
The proper gear ratio in the transmission allows the vehicle to operate at highway speed while remaining at a very low engine speed. This is responsible for obtaining adequate fuel mileage and maintaining the durability of the engine.