Pressure angle

The pressure angle gives the direction normal to the tooth profile.

To run gears together properly their pressure angles must be matched.

The force transmitted during the mating of gear teeth acts along the normal.

The force along the pitch line which is responsible for power transmission is proportional to the cosine of pressure angle.

The one which exerts thrust (perpendicular to the pitch line) is proportional to the sine of pressure angle.

Pressure angles