#4_Let's know deeply about the GEAR or COGWHEEL..

A gear or cogwheel is a part of a rotating machine with cutting teeth, or cogs, which are trapped with a second toothed portion to transmit the torque. Gear made devices can change the speed, torque and direction of a power source. Gears almost always produce a change in the torque, causing mechanical advantage through their gear ratio, and thus can be considered as a simple machine. The teeth on the two mesh gears have the same size. Two or more mesh gears working in a sequence are called a gear train or transmission. A gear can trap with a linear toothed part, which is called a rack, which produces translation rather than rotation.
The gears in transmission are analogous to wheels in a cross, belt pulley system. One advantage of gear is that the gear's teeth inhibit the inclination.
When there are two gear traps, one gear is larger than the other, then a mechanical advantage is generated, in which the speed of rotation occurs, and in the proportion of their diameter, the two gear's torque is different.
In the broadcast with many gear ratios - such as bicycles, motorcycles and cars - the word "gear" refers to the gear ratios rather than the actual physical gear in the form of "first gear". The term describes the same equipment, even if the gear ratio is continuous rather than discrete, or when the device does not actually contain gear, as one continuous variable is in transmission.

Comparison with drive mechanisms

Fixed proportions that give tooth gear provide a benefit on other drives (such as traction drives and V-belts) in precise machines, such as the exact velocity ratio. In cases where drivers and followers are proximal, gear also has a small number of essential parts on other drives as well; The downside is that gear is more expensive for construction and their lubrication requirements can cost up to a high operating cost per hour.

As soon as possible I will post all types of gear in the name of @0_gearname like As mentioned below

Types of GEAR
@1_Spur Gear
@2_Helical Gear
@3_Herringbone Gear
@4_Bevel Gear
@5_Worm Gear
@6_Rack and Pinion
@7_Internal and External Gear
@8_Face Gear
@9_Sprcokets