In the previous sections, the development of conjugate bevel gearsets via hand calculations was
demonstrated. The goal of this exercise was to encourage the reader to gain a basic understanding of
the theory of bevel gears. This knowledge will help gear engineers to better judge bevel gear design
and their manufacturing methods.
In order to make the basis of this learning experience even more realistic, this chapter will convert
a conjugate bevel gearset into a gearset that is suitable in a real-world application. Length and profile
crowning will be applied to the conjugate flank surfaces. Just as in the previous chapter, all computations
are demonstrated as manual hand calculations. This also shows that bevel gear theory is not as
complicated as commonly assumed.
This article is the fourth installment in Gear Technology's series of excerpts from
Dr. Hermann J. Stadtfeld's book, Gleason Bevel Gear Technology. The first three
excerpts can be found in our June, July and August 2015 issues.
In the previous chapter, we demonstrated the development of a face-milled spiral bevel gearset. In this section, an analogue face-hobbed bevel gearset is derived.
The calculation begins with the computation of the ring gear
blank data. The geometrically relevant parameters are shown in Figure 1. The position of the teeth relative to the blank coordinate system of a bevel gear blank is satisfactorily defined with...
The question is quite broad, as there
are different methods for setting various types of gears and complexity of
gear assemblies, but all gears have a few things in common.
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.
The efficiency of a gearbox is the output energy divided by the input energy. It depends on a variety of factors. If the complete gearbox assembly in its operating environment is observed, then the following efficiency influencing factors
have to be considered
This presentation introduces a new procedure that - derived from exact calculations - aids in determining the parameters of the validation testing of spiral bevel and hypoid gears in single-reduction axles.