In order to properly select a grease for a particular application, a sound knowledge of the influence of different grease components and operating conditions on the lubrication supply mechanism and on different failure modes is of great benefit.
Detection of impending gear tooth failure is of interest to every entity that utilizes geared transmissions. However, it is of particular significance at the Gear Research Institute (GRI), where sponsored
efforts are conducted to establish
gear material endurance limits, utilizing gear fatigue tests. Consequently, knowing when a gear is about to fail in each and every test, in a consistent manner, is essential for producing reliable and useful
data for the gear industry.
Hard finishing technology, e.g. — honing — is used to manufacture high-performance gears. Gear honing is primarily used to hard finish small- and medium-sized automotive gears. And yet trials have shown that gears with a module larger than mn = 4 mm can also be honed efficiently, but problems often occur due to unstable process design. In this paper a model to improve the process design is described.
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.
Generating gear grinding is one of the most important finishing processes for small and medium-sized gears, its process design often determined by practical knowledge.
Therefore a manufacturing simulation with the capability to calculate key values for the process — such as the specific material removal rate — is developed here. Indeed, this
paper presents first results of a model for a local analysis of the value. Additionally, an empirical formula — based on a multiple regression model for a global value describing the process — is provided.
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.
Manufacturing involute gears using form grinding or form milling wheels are beneficial to hobs in some
special cases, such as small scale production and, the obvious, manufacture of internal gears. To
manufacture involute gears correctly the form wheel must be purpose-designed, and in this paper the
geometry of the form wheel is determined through inverse calculation. A mathematical model is presented
where it is possible to determine the machined gear tooth surface in three dimensions, manufactured by this tool, taking the finite number of cutting edges into account. The model is validated by comparing calculated results with the observed results of a gear manufactured by an indexable insert milling cutter.
Due to increasing requirements regarding the vibrational behavior of automotive
transmissions, it is necessary to develop reliable methods for noise evaluation and
design optimization. Continuous research led to the development of an elaborate method for gear noise evaluation. The presented methodology enables the gear engineer to optimize the microgeometry with respect to robust manufacturing.
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...