Law of Gearing

The law of gearing gives the condition for the tooth profiles for constant angular velocity for two mating gears, which can be explained as: “If angular velocities of two mating gears remain constant, the common normal at the point of the two teeth should always pass through a fixed point P which divides the line joining the centres in the inverse ratio of angular velocities of the gears”. In Figure 15.15,

Figure 15.15 Two Teeth in Meshing