Introduction of bevel Gears

Introduction:

The bevel gears are used for transmitting power at a constant velocity ratio between two shafts whose axe n intersect at a certain angle.

Bevel Gears:

The pitch surfaces for the bevel gear are frustums of cones.

• The elements of the cones, as shown in Fig. (a), intersect at the point of intersection of the axis of rotation.

• Since the radii of both the gears are proportional to their distances from the apex, therefore the cones may roll together without sliding.

• In Fig (b), the elements of both cones do not intersect at the point of shaft intersection. Consequently, there may be pure rolling at only one point of contact and there must be tangential sliding at all other points of contact.

• Therefore, these cones, cannot be used as pitch surfaces because it is impossible to have positive driving and sliding in the same direction at the same time.

The elements of bevel gear pitch cones and shaft axes must intersect at the same point.