beval gear

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

The most familiar types of bevel gears have pitch beval gear china angles of less than 90 degrees and they are cone-shaped. This type of bevel gear is called external because the gear teeth point outward. The pitch surfaces of meshed external bevel gears are coaxial with the gear shafts; the apexes of both surfaces are at the point of intersection of the shaft axes.

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

Bevel gears that have pitch angles of specifically 90 degrees have teeth that time outward parallel with the axis and resemble the points on a crown. That is why this type of bevel gear is called a crown gear.

Mitre gears are mating bevel gears with equal numbers of teeth and with axes at right angles.

Skew bevel gears are those that the corresponding crown gear has the teeth that are directly and oblique.