Classification of Bevel Gears

Introduction:

The bevel gears may be classified depending upon the angles between the shafts and the pitch surfaces.

Classification:

The bevel gears may be classified into the following types, depending upon the angles between the shafts and the pitch surfaces.

1. Mitre gears.

When equal bevel gears (having equal teeth and equal pitch angles) connect two shafts whose axes intersect at right angle, as shown in Fig. (a), then they are known as mitre gears.
 

2. Angular bevel gears.

When the bevel gears connect two shafts whose axes intersect at an angle other than a right angle, then they are known as angular bevel gears.

3. Crown bevel gears.

When the bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90º, then it is known as a crown gear. The crown gear corresponds to a rack in spur gearing, as shown in Fig.b).

4. Internal bevel gears.

When the teeth on the bevel gear are cut on the inside of the pitch cone, then they are known as internal bevel gears.

Note : The bevel gears may have straight or spiral teeth. It may be assumed, unless otherwise stated, that the bevel gear has straight teeth and the axes of the shafts intersect at right angle.