Law of gearing says that the common normal at the point of contact between a pair of teeth must always pass through the pitch point.

In case the addenda on pinion and wheel is such that the path of approach and path of recess are half of their maximum possible values, then

Module, m = D /T.

It is the ratio of the pitch circle diameter in millimeters to the number of teeth.

Pitch circle is an imaginary circle which by pure rolling action, would give the same motion as the actual gear.

The fundamental condition of correct gearing is the common normal at the point of contact between a pair of teeth must always pass through the pitch point.

When equal bevel gears (having equal teeth) connect two shafts whose axes are mutually perpendicular, then the bevel gears are known as mitres.

ηmax = cos (θ + φ ) + 1/ cos (θ − φ ) + 1

The two parallel and co-planar shafts connected by the gears. These gears are called spur gears and the arrangement is known as spur gearing. These gears have teeth parallel to the axis of the wheel as shown in Fig. 12.1. Another name given to the spur gearing is helical gearing, in which the teeth are inclined to the axis.

None.