Gear teeth are designed so that the release of teeth on a gear is proportional to the radius of its pitch circle, as well as so that the pitch circles of meshing gears whorl on each other without slipping. The speed ratio for a yoke of meshing gears tin live on computed from ratio of the radii of the pitch circles as well as the ratio of the release of teeth on each gear..
Two meshing gears transmit rotational motion.
The velocity v of the indicate of contact on the pitch circles is the same on both gears, as well as is given by
where input gear A has radius rA and meshes amongst output gear B of radius rB, therefore,
where NA is the release of teeth on the input gear and NB is the release of teeth on the output gear.
The mechanical advantage of a yoke of meshing gears for which the input gear has NA teeth as well as the output gear has NBteeth is given by
This shows that if the output gear GB has to a greater extent than teeth than the input gear GA, so the gear train amplifies the input torque. And, if the output gear has fewer teeth than the input gear, so the gear train reduces the input torque.
If the output gear of a gear develop rotates to a greater extent than piece of cake than the input gear, so the gear develop is called a speed reducer. In this case, because the output gear must convey to a greater extent than teeth than the input gear, the speed reducer volition amplify the input torque.