Method of generating bevel and hypoid gears

DETAILED DESCRIPTION The present invention is directed to a process of modifying standard generating motions for producing bevel and hypoid gears in order to effect desired tooth surface geometries.
Additional controlled motions are included substantially simultaneously with the standard generating motions to bring about desired surface characteristics.
The standard generating motions for bevel and hypoid gears comprise operatively engaging a rotating tool with a work piece in a predetermined rolling motion about a theoretical axis of rotation.
During generation, the rotating tool is carried in a circular arcuate path the center of which represents the axis of rotation of a theoretical generating gear.
The teeth of the theoretical generating gear, represented by the stock-removing surfaces of the tool, mesh with the work gear and thus form the tooth surfaces of the work piece.
A first inventive additional controlled motion comprises varying the position of intersection of the theoretical axis and the pitch plane relative to the work gear.
This additional motion may be described by a mathematical function and may take place parallel to the instant line of relative rotation, thus changing the generating cone distance in process, in a direction perpendicular to the instant line of relative rotation, thus changing the generating work offset in process, or in a direction containing components of both the above-named directions.
Furthermore, the direction of motion may vary during the generating process.
A second inventive additional controlled motion comprises varying the orientation and position of the teeth of the generating gear relative to the body of the generating gear which carries them.
These motions may also be described by a mathematical function.
The motions comprise rotating a tooth or teeth of the generating gear thereby changing the nominal spiral angle, nominal pressure angle, lengthwise and profile geometry, or combinations thereof, of the generating gear during the generation process