The conformance to specification and quality of cylindrical gears is routinely handled by the use of elemental checks i.e. lead, involute, pitch variation and runout. Since there is no reference figure to define the form accuracy for bevel gears as the involute helicoid does for a cylindrical involute gear, it has not, until recently, been possible to check for tooth form accuracy, i.e. lead and profile (involute), on bevel gears. (1)
The use of a coordinate measuring machine during the development process allows for optimization of the machine settings to achieve a tooth form which is proper for the intended application.
This paper describes the development of a procedure used to establish and control the tooth form of heavy duty drive axle spiral bevel pinions and ring gears.
Involved in the procedure was the determination of the machine capability using statistical studies made on each battery of equipment, establishment of appropriate soft and hard reference gear sets and a procedure to duplicate the tooth surfaces on repeated set-ups encountered in the “Just In Time Concept”.
The results have been greater consistency in gear sets and much less dependence on subjective judgement in the control of the soft topography.