Toothing law

Shifting of an involute toothing

The law of toothing describes how the teeth of interlocking ("meshing") gears must be shaped in order to achieve the optimum effect. The aim here is to achieve a pure rolling movement at the contact point of the teeth (on the "tooth flanks"). A sliding of the teeth on each other creates abrasion , which should be avoided. In addition, this is more kinetic energy is converted into heat, the efficiency impaired.

The law of toothing states that the normal (vertical) of the two contact surfaces (on the tooth flanks) must always pass through the pitch point C so that an angular velocity can be transferred from one shaft to a second with a uniform ratio. In the simplest case, the pitch point C is the point of contact on the imaginary connecting line between the pivot points of the two gears.