Two important concepts in gearing are pitch surface and pitch position. The pitch surface of a gear may be the imaginary toothless surface area that you would have by averaging out the peaks and valleys of the beval gear china average person teeth. The pitch surface area of an ordinary gear is the form of a cylinder. The pitch angle of a equipment is the angle between the face of the pitch surface area and the axis.

The most familiar kinds of bevel gears have pitch angles of significantly less than 90 degrees and they are cone-shaped. This type of bevel gear is named external since the gear teeth point outward. The pitch areas of meshed external bevel gears are coaxial with the apparatus shafts; the apexes of both surfaces are at the idea of intersection of the shaft axes.

Bevel gears that have pitch angles in excess of ninety degrees have teeth that point inward and so are called internal bevel gears.

Bevel gears that have pitch angles of precisely 90 degrees have teeth that point outward parallel with the axis and resemble the factors on a crown. That is why this type of bevel gear is named a crown gear.

Mitre gears are mating bevel gears with the same amounts of teeth and with axes in right angles.

Skew bevel gears are those that the corresponding crown gear has tooth that are straight and oblique.