When we hear the word “gear”, the first thing that flashes in our mind is the one which is used in a motor bike to change the speed of motion. But that is not all. Gears are used anywhere and everywhere. Be it any mechanical device, be it the smallest wrist watch or be it the largest industrial gears which are of 5m diameter, they have a found wide range of applications. The most commonly seen bicycle also works with the action of these mechanical cogwheels. Gears generally work in pairs whose teeth would be non divisible numbers. When one turns clockwise other would be in anticlockwise motion.
The number of teeth on the gears decides the gear ratio which is rather too important in an automotive industry. Gear ratio is related to the number of teeth on the meshing gears. It is expressed as mathematical ratio like 2:1, 3:2 etc. If the larger gear turns one revolution for every two revolutions of the smaller gear then the gear ratio would be 2:1.
These useful gears are manufactured using the metals like copper, brass, steels, cast iron and their alloys.
The most primitive form of gear which is still in use is the wooden gears which are used in textile and flour mills. Gear manufacturing involves lot of materials and processes and thus proves to be expensive. So because of this reason gears have to be maintained properly.
The reason to have non divisible teeth on the gears is to avoid the wear of the gears. If suppose the gears have 10 and 30 teeth each, then for every 3 turns of the first gear the larger gear would mesh with the same teeth and thus causes excessive wear on the gears. Maintaining gears also involves regular application of oil and other lubricants, regular cleaning with soft cloth, etc.
The gear oils have improved a lot that provides greater protection to the component and keeps them well lubricated.