Gears are toothed wheels that, when combined in different configurations, can change the speed, direction, and/or torque of a power source.
Gear sizes are typically expressed by number of teeth, circumference, diameter, or radius. Gears can be used to create mechanical advantage equal to the ratio of the driver gear over the driven gear; this ratio is also referred to as the gear ratio.
|Axis||Where the shaft passes through|
|Cog||A tooth on a wheel|
|Cylinder||The "wheel" portion of the gear|
|Driver Gear||A gear rotated by a power source|
|Driven Gear||A gear rotated by a driver gear|
|Gear ratio||The ratio of the sizes of two gears, typically the driver gear over the driven gear|
|Gear train||The combination of two or more gears|
|Pitch Circle||The circumference the the gear, measured at the point of force between two meshed gears|
|Tooth||The lever protruding from the cylinder or cone|
Video Introduction to Gears
Resources for Learning About Gears
Broader Topics Related to Gears
The basics of angular motion
Learn about mechanical advantage
Build and deconstruct mechanical devices
Learn about torque: Force that causes an object to rotate around an axis.