A single tooth bending (STB) test procedure has been developed to optimally map gear design parameters. Also, a test program on case-carburized, aerospace standard gears has been conceived and performed in order to appreciate the influence of various technological parameters on fatigue resistance and to draw the curve shape up to the gigacycle
region.
Beveloid gears are used to accommodate a small shaft angle. The manufacturing technology used for beveloid gearing
is a special setup of cylindrical gear cutting and grinding machines. A new development, the so-called Hypoloid
gearing, addresses the desire of gear manufacturers for more freedoms. Hypoloid gear sets can realize shaft angles between zero and 20° and at the same time, allow a second shaft angle (or an offset) in space that provides the freedom to connect two points in space.
This article examines the dry hobbing capabilities of two cutting tool materials—powder metallurgical high-speed steel (PM-HSS) and cemented carbide. Cutting trials were carried out to analyze applicable cutting parameters and possible tool lives as well as the process reliability. To consider the influences of the machinability of different workpiece materials, a case hardening steel and
a tempered steel were examined.
No matter how well gears are designed and manufactured, gear corrosion can occur that may easily result in catastrophic failure. Since corrosion is a sporadic and rare event and often difficult to observe in the root fillet region or in finely pitched gears with normal visual inspection, it may easily go undetected. This paper
presents the results of an incident
that occurred in a gear manufacturing
facility several years ago that resulted in pitting corrosion and intergranular attack (IGA).
The gear tooth fillet is an area of maximum bending stress concentration. However, its profile is typically less specified in the gear drawing and hardly controlled during gear inspection in comparison with the gear tooth flanks. This paper presents a fillet profile optimization technique for gears with symmetric and asymmetric teeth based on FEA and a random search method. It allows achieving substantial bending stress
reduction in comparison with traditionally designed gears. This bending stress reduction can be traded for higher load capacity, longer lifetime, lower noise and vibration and cost reduction.
Often, the required hardness qualities of parts manufactured from steel can only be obtained through suitable heat
treatment. In transmission manufacturing, the case hardening process is commonly used to produce parts with a hard and wear-resistant surface and an adequate toughness in the core. A tremendous potential for rationalization, which is only
partially used, becomes available if the treatment time of the case hardening process is reduced. Low pressure carburizing (LPC) offers a reduction of treatment time in comparison to conventional gas carburizing because of the high carbon
mass flow inherent to the process (Ref. 1).
A computational fluid dynamics (CFD) method is adapted, validated and applied to spinning gear systems with emphasis on predicting windage losses.
Several spur gears and a disc are studied. The CFD simulations return good agreement with measured windage power loss.
As is well known in involute gearing, “perfect” involute gears never work perfectly in the real world.
Flank modifications are often made to overcome the influences of errors coming from manufacturing and assembly processes as well as deflections of the system. The same discipline applies to hypoid gears.
It may not be widely recognized that most of the inspection data supplied by inspection equipment, following the
practices of AGMA Standard 2015 and similar standards, are not of elemental accuracy deviations but of some form of composite deviations. This paper demonstrates the validity of this “composite” label by first defining the nature of a true
elemental deviation and then, by referring to earlier literature, demonstrating how the common inspection practices for involute, lead (on helical gears), pitch, and, in some cases, total accumulated pitch, constitute composite measurements.
Traditionally, gear rating procedures consider manufacturing accuracy in the application of the dynamic factor, but
only indirectly through the load distribution are such errors in the calculation of stresses used in the durability and gear strength equations. This paper discusses how accuracy affects the calculation of stresses and then uses both statistical
design of experiments and Monte Carlo simulation techniques to quantify the effects of different manufacturing and
assembly errors on root and contact stresses.