Recent Advances in the Analysis of Spiral Bevel Gears
A review of recent progress for the analysis of spiral bevel gears will be described. The foundation of this work relies on the description of the gear geometry of face-milled spiral bevel gears via the approach developed by Litvin. This methodology was extended by combining the basic gear design data with the manufactured surfaces using a differential geometry approach, and provides the data necessary for assembling three-dimensional finite element models. The finite element models have been utilized to conduct thermal and structural analysis of the gear system. Examples of the methods developed for thermal and structural/contact analysis are presented.
A Method for Determining Spiral-Bevel Gear Tooth Geometry for Finite Element Analysis
Abstract : Spiral bevel gears are currently used in all helicopter power transmission systems. This type of gear is required to turn the corner from a horizontal engine to the vertical rotor shaft. These gears carry large loads and operate at high rotational speeds. Recent research has focused on understanding many aspects of spiral bevel gear operation, including gear geometry, gear dynamics, lubrication, stress analysis and measurement, misalignment, and coordinate measurements, as well as other areas. An analytical method has been developed to determine gear-tooth surface coordinates of face-milled spiral bevel gears. The method uses the basic gear design parameters in conjunction with the kinematical aspects of spiral bevel gear manufacturing machinery. A computer program entitled SURFACE was developed to calculate the surface coordinates and provide three-dimensional model data that can be used for finite element analysis. Development of the modeling method and an example case are presented in this report. This method of analysis could also be applied in gear inspection and near-net-shape gear forging die design.
Influence of Relative Displacements Between Pinion and Gear on Tooth Root Stresses of Spiral Bevel Gears
Int.roduction The manufacturing quality of spiral bevel gears has achieved a very high standard. Nevertheless, the understanding of the real stress conditions and the influences. of certain parameters is not satisfactory. This refers to, the influence of geometric da.ta (like flank curvature. crowning, spiral angle, etc.) or mounting conditions on stress distribution and load capacity. The design of bevel. gears in genera] is based on experience. The investigation of tooth root stresses at spiral bevel gears, described in this paper, was initiated under these aspects. This research program started in 1981 at the FZG, Munich (Porschungsstelle flir Zahnrader und Getriebeba.uGear Research Laboratory). It is financed by the DFG (Deutsche Porschungs-Cemelnschan - German Research Association). The research method Iollows a line oJ similar basic studies on tooth root stresses for spur rn and heHcal(2) gears and is also mainly based on experimental investigations. The main objective was to gam reliable information on the amount, direction, and distribution of root stresses in spiral bevel gears by direct measurements. Especially the influence of size and location of the contact pattern on the working conditions of a bevel gear set should be investigated. In this connection, the influence of the amount of crowning of the pinion teeth should be examined. The results of this investigation were intended to provide data For verification of similar theoretical calculations!" and, therefore, to present a contribution to a more accurate and realistic calculation ,of the load capacity of bevel gears. The measuring method is explained and some general results on the distribution of tooth root stresses are discussed. In particular, the influence oE various centact patterns