At first sight the appearance of 5-axis milling for bevel gears opens new possibilities in flank form
design. Since in comparison to existing machining methods applying cutter heads no kinematic
restrictions exist for 5-axis milling technology, any flank form can be machined.
Nevertheless the basic requirements for bevel gears did not change. Specifications and functional
requirements like load carrying capacity and running behavior are still increasing demands for design
and manufacturing. This paper describes the demands for gear design and gives an overview about
different design principles in the context of the surrounding periphery of the gear set.
This proposed standard would not make any recommendations
regarding the required quality for any application. The
intent is to establish standard pre-finish quality classes for typical
finishing operations, which only include the inspection elements
that are important to properly evaluate pre-finish gear
quality as it applies to the finishing operation. It would be the
responsibility of the manufacturing/process engineer, quality
engineer, or other responsible individual to establish the
required pre-finish quality class for their application.
The geometry of the bevel gear is quite complicated to describe mathematically, and much of the overall surface topology of the tooth flank is dependent on the machine settings and cutting method employed. AGMA 929-A06 — Calculation of Bevel Gear Top Land and Guidance on Cutter Edge Radius — lays out a practical approach for predicting the approximate top-land thicknesses at certain points of interest — regardless of the exact machine settings that will generate the tooth form. The points of interest that AGMA 929-A06 address consist of toe, mean, heel, and point of involute lengthwise curvature. The following method expands upon the concepts described in AGMA 929-A06 to allow the user to calculate not only the top-land thickness, but the more general case as well, i.e. — normal tooth thickness anywhere along the face and profile of the bevel gear tooth. This method does not rely on any additional machine settings; only basic geometry of the cutter, blank, and teeth are required to calculate fairly accurate tooth thicknesses. The tooth thicknesses are then transformed into a point cloud describing both the convex and concave flanks in a global, Cartesian coordinate system. These points can be utilized in any modern computer-aided design software package to assist in the generation of a 3D solid model; all pertinent tooth macrogeometry can be closely simulated using this technique. A case study will be presented evaluating the accuracy of the point cloud data compared to a physical part.
For more than 22 years, I've been dropping rocks down the well of the gear industry's public opinion. Most every issue, I drop another rock. Sometimes I think I hear a faint splash, but most times I just wait.