Gears are used in tons of mechanical products. They do a number of important jobs, but most important, they provide a gear reduction in motorized equipment. That is key because, frequently, a small motor spinning very fast can provide more than enough power for a device, but not enough torque. For instance, an electric screwdriver has a large gear reduction because it needs lots of torque to turn screws, bu­t the motor only produces a little quantity of torque at a higher speed. With a gear reduction, the result speed could be reduced as the torque is increased.

Another thing gears do is adapt the direction of rotation. For instance, in the differential between your rear tires of your car, the power is normally transmitted by a shaft that operates down the greenhouse motor center of the automobile, and the differential has to change that power 90 degrees to apply it to the tires.

There are a lot of intricacies in the various types of gears. In this post, we’ll learn exactly how the teeth on gears function, and we’ll talk about the different type­s of gears you find in all types of mechanical gadgets.­


On any equipment, the ratio is determined by the distances from the guts of the gear to the idea of contact. For instance, in a device with two gears, if one gear is twice the diameter of the additional, the ratio would be 2:1.

One of the most primitive types of gears we’re able to look at will be a wheel with wooden pegs sticking out of it.

The problem with this type of gear is that the length from the center of each gear to the idea of contact changes as the gears rotate. This implies that the gear ratio adjustments as the gear turns, meaning that the output acceleration also changes. If you used a equipment like this in your car, it would be impossible to maintain a constant speed — you would be accelerating and decelerating continuously.

Many modern gears use a special tooth profile named an involute. This profile has the very important house of maintaining a constant speed ratio between the two gears. Like the peg wheel above, the contact point moves; but the form of the involute equipment tooth compensates for this movement. See this section for details.

Now let’s take a look at some of the different types of gears.