Advancement of Straight and Spiral Bevel Gear Technology

摘要

The need for increased load capacity of bevel gears in aircraft applications had led to a review of existing methods for determining bevel gear tooth strength. Several methods were reviewed, but it was found that the existing AGMA method was basically the most sound. Fatigue testing of spiral bevel gears showed that vacuum-melt steel would permit higher stresses than those allowed by the present rating practices. A study of lengthwise tooth curvature (cutter diameter) showed that this factor has a significant effect on gear tooth strength. The use of small cutter diameters is shown to improve gear tooth strength by as much as 40 percent under the most favorable conditions. New formulas for effective face width and size factor were developed, which result in stress values more nearly equal to the true stresses in gear teeth. A change in the method for locating the most critical point of loading has resulted in an improved strength balance between the pinion and mating gear. (Author)