Types of Gears

A gear can be defined as a toothed wheel which can be engaged into another toothed wheel or gear in order to transmit energy that facilitates change of speed and direction of motion. The gear, as mentioned above, is widely used in mechanical devices. The teeth of the gear are principally carved on wheels, cylinders or cones. Many devices that we use in our day-to-day life have their working principle as the gear. The tooth and wheel of the gear are basic working parts of all gears.

Different Types of Gears

Internal and External Gears
The most simple form of gears that are used to control locomotion of a mobile body are external gears. The teeth of a gear that interconnects with another gear are carved on exterior of the wheel or cylinder or cone. The exterior gear is many a time used along with a chain, like in a bicycle or motorcycle. More complex combination of exterior gears are used to manufacture gear boxes for vehicles. The design of interior gear is similar to that of an exterior gear. The only difference is that the teeth are carved inside the wheel, and gear is most of the time used for perpendicular transfer of energy. The teeth of these gears that apply the effort have a perpendicular or straight projection.

Spur Gears
The spur gear is also known as straight-cut gear. The design of this gear is very similar to that of a simple exterior gear. The spur gear, however has greater break strength than an exterior gear, and are shaped like a cylindrical disk. Another difference between exterior gear and spur gear is radial projection of teeth. The uppermost portion of this gear is carved in such a manner that it is always parallel to the axis of rotation.

Helical Gears
Helical gears are an upgraded version of spur gears. The difference is that, axis of teeth of gear is different. As compared to other gears, like exterior gears and spur gears the axis of the helical gears is directed in a slanting direction. Due to this direction of axis, the teeth get the appearance of a helix. The helical teeth of these gears were developed to replace spur gears that could not last the stress high-speed rotation and resolution.

Bevel Gears
Bevel gears are gears that are essentially made up cones or conical surfaces. The bevel gear is used in transfer of energy from one angle to another. It is especially useful for a perpendicular transfer of energy. Bevel gears are further classified according to the angle, as per which they transfer their energy.

Crown Gear
The crown gear as the name suggests is shaped like a crown. The teeth of a crown gear are pointed in upward direction. The teeth are perpendicularly carved on the wheel of the gear. It is often considered to by an evolution of bevel gears.

All the gears that are presently used, have the same principle of physics, and form an integral part of the modern mechanisms. The gears have been modified and re-engineered to form different designs and execute different functions.