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Articles About FEA
This paper deals with analysis of the load sharing percentage between teeth in mesh for different load conditions throughout the profile for both sun and planet gears of normal and HCR gearing—using finite element analysis. (FEA).
The complete and accurate solution t the contact problem of three-dimensional gears has been, for the past several decades, one of the more sought after, albeit elusive goals in the engineering community. Even the arrival on the scene in the mid-seventies of finite element techniques failed to produce the solution to any but the most simple gear contact problems.
The load carrying behavior of gears is strongly influenced by local stress concentrations in the tooth root and by Hertzian pressure peaks in the tooth flanks produced by geometric deviations associated with manufacturing, assembly and deformation processes. The dynamic effects within the mesh are essentially determined by the engagement shock, the parametric excitation and also by the deviant tooth geometry.
Recent advances in spiral bevel gear geometry and finite element technology make it practical to conduct a structural analysis and analytically roll the gear set through mesh. With the advent of user-specific programming linked to 3-D solid modelers and mesh generators, model generation has become greatly automated. Contact algorithms available in general purpose finite element codes eliminate the need for the use and alignment of gap elements. Once the gear set it placed in mesh, user subroutines attached to the FE code easily roll it through mesh. The method is described in detail. Preliminary result for a gear set segment showing the progression of the contact line load is given as the gears roll through mesh.
How the latest techniques and software enable faster spiral bevel and hypoid design and development.
The geometry factor, which is a fundamental part of the AGMA strength rating of gears, is currently computed using the Lewis parabola which allows computation of the Lewis form factor.(1) The geometry factor is obtained from this Lewis factor and load sharing ratio. This method, which originally required graphical construction methods and more recently has been computerized, works reasonably well for external gears with thick rims.(2-6) However, when thin rims are encountered or when evaluating the strength of internal gears, the AGMA method cannot be used.
In the design of any new gear drive, the performance of previous similar designs is very carefully considered. In the course of evaluating one such new design, the authors were faced with the task of comparing it with two similar existing systems, both of which were operating quite successfully. A problem arose, however, when it was realized that the bending stress levels of the two baselines differed substantially. In order to investigate these differences and realistically compare them to the proposed new design, a three-dimensional finite-element method (FEM) approach was applied to all three gears.
The effect of load speed on straight and involute tooth forms is studied using several finite-element models.
This paper describes the investigation of a steel-and-plastic gear transmission and presents a new hypothesis on the governing mechanism in the wear of plastic gears.
As a result of extensive research into the vibration characteristics of gear drives, a systematic approach has evolved, by which damaging resonances can be eliminated. The method combines finite element techniques with experimental signature and modal analyses. Implementation of the bulk of the method can be carried out early in the design stage. A step-by-step description of the approach, as it was applied to an existing accessory drive, is given in the text. It is shown how premature bearing failures were eliminated by detuning the torsional oscillations of a gearshaft. A dramatic reduction in vibration levels was achieved as a result of detuning the problem gear. The proposed approach can be extended to other types of rotating machines.
Last month I attended a meeting in Mexico City sponsored by CIATEQ, a quasi-governmental organization in Mexico, which has as one of its aims the encouragement of the growth of the gear industry in Mexico. The purpose of the meeting was to provide a catalyst among the attendees to form a Mexican equivalent of AGMA and to encourage an alliance with AGMA. Joe Franklin, the Executive Director of AGMA, Bill Boggess, the President, Vice-President Ray Haley, and I were among the few Americans at the meeting.
Tooth contact under load is an important verification of the real contact conditions of a gear pair and an important add-on to the strength calculation according to standards such as ISO, AGMA or DIN. The contact analysis simulates the meshing of the two flanks over the complete meshing cycle and is therefore able to consider individual modifications on the flank at each meshing position.
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.
Minimizing gear losses caused by churning, windage and mesh friction is important if plant operating costs and environmental impact are to be minimized. This paper concentrates on mesh friction losses and associated scuffing risk. It describes the preliminary results from using a validated, 3-D Finite Element Analysis (FEA) and Tooth Contact Analysis (TCA) program to optimize cylindrical gears for low friction losses without compromising transmission error (TE), noise and power density. Some case studies and generic procedures for minimizing losses are presented. Future development and further validation work is discussed.
Welcome to our Product News page. Here we feature new products of interest to the gear and gear products markets.
Welcome to our Product News page. Here we feature new products of interest to the gear and gear products markets.
Welcome to our Product News page. Here we feature new products of interest to the gear and gear products markets.
What is so unique about gear manufacturing and inspection? Machining is mostly associated with making either flat or cylindrical shapes. These shapes can be created by a machine's simple linear or circular movements, but an involute curve is neither a straight line nor a circle. In fact, each point of the involute curve has a different radius and center of curvature. Is it necessary to go beyond simple circular and linear machine movements in order to create an involute curve? One of the unique features of the involute is the fact that it can be generated by linking circular and linear movements. This uniqueness has become fertile soil for many inventions that have simplified gear manufacturing and inspection. As is the case with gear generating machines, the traditional involute inspection machines take advantage of some of the involute properties. Even today, when computers can synchronize axes for creating any curve, taking advantage of involute properties can be very helpful. I t can simplify synchronization of machine movements and reduce the number of variables to monitor.
Welcome to our Product News page. Here we feature new products of interest to the gear and gear products market.
Several articles have appeared in this publication in recent years dealing with the principles and ways in which the inspection of gears can be carried out, but these have dealt chiefly with spur, helical and bevel gearing, whereas worm gearing, while sharing certain common features, also requires an emphasis in certain areas that cause it to stand apart. For example, while worm gears transmit motion between nonparallel shafts, as do bevel and hypoid gears, they usually incorporate much higher ratios and are used in applications for which bevel would not be considered, including drives for rotary and indexing tables in machine tools, where close tolerance of positioning and backlash elimination are critical, and in situations where accuracy of pitch and profile are necessary for uniform transmission at speed, such as elevators, turbine governor drives and speed increasers, where worm gears can operate at up to 24,000 rpm.
No one (not even you and I) consistently makes parts with perfect form and dimensions, so we must be able to efficiently check size and shape at many stages in the manufacturing and assembly process to eliminate scrap and rework and improve processes and profits. Automated inspection systems, which are widely used in all kinds of manufacturing operations, provide great efficiencies in checking individual features, but may not be as effective when asked to evaluate an entire part. You need to know why this is true and what you can do to improve your part yields.
A special advertising section featuring gear industry exhibitors at IMTS 2012.
This report presents some interim results from an ongoing project being performed by INFAC, the Instrumented Factory for Gears. The purposes of this initial phase of the project were to demonstrate the feasibility of robotic automated deburring of aerospace gears, and to develop a research agenda for future work in that area.
Welcome to our Software Bits page. Here we feature new software products for gear design, manufacturing and testing.
The latest machines, tooling and technology for gear grinding were featured at IMTS 2012.
This issue's look at the web features videos posted at geartechnology.com, featuring Forest City Gear and Star SU.
Composite spur gears were designed, fabricated and tested at NASA Glenn Research Center. The composite web was bonded only to the inner and outer hexagonal features that were machined from an initially all-metallic aerospace quality spur gear. The hybrid gear was tested against an all-steel gear and against a mating hybrid gear. Initial results indicate that this type of hybrid design may have a dramatic effect on drive system weight without sacrificing strength.
Publisher Michael Goldstein explores Gear Technology's history and its future as he introduces the back issue archive online and our new features and columns for 2013.
Helical gear pairs with narrow face width can be theoretically classified into three categories over the contact ration domain whose abscissa is the transverse contact ration and whose ordinate is the overlap contact ratio. There is a direct relation between vibration magnitude and shaft parallelism deviation. To clarify the effect of the tooth deviation types on the vibration behavior of helical gear pairs, performance diagrams on vibration are introduced. the acceleration levels of gear pairs are shown by contour lines on the contact ratio domain. Finally, the performance of gears with bias-in and bias-out modifications is discussed considering the effect of the shaft parallelism deviation with use of the developed simulator on a helical gear unit. It becomes clear that there is an asymmetrical feature on the relation between the vibration magnitude of a gear pair and the direction of each deviation.
Electroless Nickel (EN) plating, a process dating back to the 1940s, is one of the predominant metal finishing methods today. It is especially suitable for the gear industry, whose end uses span innumerable other industries, providing an endless assortment of requirements, environments, materials and specifications. EN plating has a broad array of functional features, which include:
Welcome to our Product News page. Here we will feature new products of interest to the gear and gear products markets.
The complete events section from March/April 2006, including a feature on the Koepfer Gear School and our technical calendar.
In 2005, Gear Expo debuted its first Solutions Center, a forum that features short exhibitor presentations on gear-related topics. This year, AGMA says the Solutions Center will return with a slightly different format.
New machine promises DIN 2 accuracy and unique features at low cost.
The quality of molded plastic gears is typically judged by dimensional feature measurements only. This practice overlooks potential deficiencies in the molding process.
The October 2011 issue of Gear Technology featured the article “Low-Distortion Heat Treatment of Transmission Components,” which covered the combination of low-pressure carburizing and high pressure gas quenching in an automotive environment. Here, heat treating expert Dan Herring explains why oil quenching is an appropriate choice for many applications.
AGMA Voices is a new feature brought to you by Gear Technology in cooperation with the American Gear Manufacturers Association. AGMA Voices will give you opinions, insight and information presented by various AGMA staff members, board members, committee heads and volunteers. In this column, Gear Technology will bring you guest editorials from the gear industry’s leading association.
The organizers of Gear Expo 2007 promise to combine the most popular features of shows past with some innovations for this year’s attendees. By the time the show closes on October 10, the association hopes its targeted 175 exhibitors walk away with new insights leading to profitability and renewed contacts.
The complete product news section from the January/February 2009 issue of Gear Technology, featuring giant-sized David Brown girth gears, gear inspection up to 4.5 meters and the latest Gleason gear grinder.
This special advertising section features some of the premier gear-related exhibitors at IMTS 2004.
Special advertising section featuring gear industry exhibitors.
There’s a bustle of activity as exhibitors prepare for America’s most significant manufacturing trade show. The red carpets are ready, the lights are being tested, and the crowds are gathering with anticipation. Amid the excitement, Gear Technology has managed to sneak under the usher’s ropes to provide you with this advance look at some of the gear-related products and technologies that will be featured at IMTS 2004.
In today’s manufacturing environment, shorter and more efficient product development has become the norm. It is therefore important to consider every detail of the development process, with a particular emphasis on design. For green machining of gears, the most productive and important process is hobbing. In order to analyze process design for this paper, a manufacturing simulation was developed capable of calculating chip geometries and process forces based on different models. As an important tool for manufacturing technology engineers, an economic feasibility analysis is implemented as well. The aim of this paper is to show how an efficient process design—as well as an efficient process—can be designed.
Readers respond with their own crazy ideas about the mystery gear on the mountain featured in September/October 2008's Addendum column.
The objective of this paper is to demonstrate that transmission gears of rotary-wing aircraft, which are typically scrapped due to minor foreign object damage (FOD) and grey staining, can be repaired and re-used with signifi cant cost avoidance. The isotropic superfinishing (ISF) process is used to repair the gear by removing surface damage. It has been demonstrated in this project that this surface damage can be removed while maintaining OEM specifications on gear size, geometry and metallurgy. Further, scrap CH-46 mix box spur pinions, repaired by the ISF process, were subjected to gear tooth strength and durability testing, and their performance compared with or exceeded that of new spur pinions procured from an approved Navy vendor. This clearly demonstrates the feasibility of the repair and re-use of precision transmission gears.
The Forest City Gear booth at Gear Expo featured a wide variety of gears utilized in medical equipment, Indy cars, fishing reels, even the recently launched Mars Rover. Scattered among Forest City’s products in Cincinnati were some unique gear sculptures created by an artist that finds more inspiration from the pages of industrial magazines than art galleries.
The art of gear hobbing has advanced dramatically since the development and introduction of unique machine and tool features such as no backlash, super rigidity, automatic loading of cutting tools, CNC controls, additional machine power and improved cutter materials and coatings. It is essential to utilize all these features to run the machine economically.
Welcome to our Product News page. Here we feature new products to the gear and gear products markets.
Welcome to out Product News page. Here we feature new products of interest to the gear and gear products markets.
Welcome to our new Product News page. Here we will feature new products of interest to the gear and gear products markets.
This is Part II of a two-part series on the basics of gear hobbing. Part I discussed selection of the correct type of hobbing operation, the design features of hobs and hob accuracy. This part will cover sharpening errors and finish hob design considerations.
Expertise is a resource that's hard to sustain. We're doing our part via our "Ask the Expert" feature. How about you?
This article investigates fillet features consequent to tooth grinding by generating methods. Fillets resulting from tooth cutting and tooth grinding at different pressure angles and with different positions of grinding wheel are compared. Ways to improve the final fillet of the ground teeth with regard to tooth strength and noise, as well as the grinding conditions, are shown. "Undergrinding" is defined and special designs for noiseless gears are described.
A response to last issue's "Ask the Expert" feature on efficiency of hypoid gearing.
Gleason's GMS analytical gear inspection systems provide all the right features at Eaton Corp.
Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ration under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque and power. Significant parameters in the design are the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near-optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.
The acceptance by discerning customers of passenger cars is dependent upon both the actual noise lever and the subjective noise character. The subjective noise character itself can contain, among other features, undesirable noise phenomena which become apparent at certain points in the vehicle operating range. One such critical phenomenon is gear rattle, which is mainly present under low speed, high load conditions. Due to changes in the angular velocity of the crankshaft, gear rattle under driving conditions occurs at the unloaded gears and splines.
News Items About FEA
1 Two-Piece Balanced Gear Clamps From Sterling Feature Balanced Design (April 5, 2006)
A new series of two-piece clamps for retaining gears on shafts, introduced by Sterling Instrument, provide easy installation when neither... Read News
2 Ikona Exec Featured in Online Broadcast (April 12, 2006)
Ikona Gear's CEO Ray Polman was featured live on Market News First on September 5. Market News First is an online market news prov... Read News
3 New Vibration Mounts from AAC Feature Finger-Flex Ring and Bushing Isolators (April 2, 2006)
The new V10Z 4 Series of vibration mounts from Advanced Antivibration Components feature unique "Finger-Flex" isolators which are designe... Read News
4 Adcoles New Gage Features Spindle Refinements (January 20, 2006)
A new, high accuracy vers... Read News
5 New Software Feature from UTS (January 31, 2005)
The Player software for sharing Excel spreadsheets and mathematical models created in the 5.0 Solver Premium Edition is available from Un... Read News
6 Midwest Motions New Control Features Built-In Reversing Switch and Speed Adjust Potentiometer (January 15, 2006)
7 Stainless Steel Cut-off Wheels Feature Thin Profile (April 22, 2006)
The Alpha Green cut-off wheels for stainless steel feature a thin profile that cuts faster than conventional thicker wheels and are avail... Read News
8 Sumitomos New Inserts Feature Six Cutting Edges (April 22, 2006)
Sumitomo Electrics new 55 degree SumiTurn T-REX triangle insert was launched as a replacement for the 55 degree DNMG. The T-REX fea... Read News
9 FeatureCAM Helps Renishaw Turn Designers into Machinists (February 23, 2011)
Metrology and healthcare specialist Renishaw has been able to improve greatly the productivity of its rapid prototyping department by tur... Read News
10 KISSsoft Updates Features in the Contact Analysis (July 13, 2011)
In the contact analysis of KISSsoft, the effects of shaft deformations may now be precisely evaluated (module ZA30). The results of shaft... Read News
11 Mahr Federal to Feature Digital Caliper Line at IMTS (June 25, 2010)
Mahr Federal will be featuring a new generation of its line of MarCal digital calipers at IMTS, September 13-18, 2010, at McCormick Place... Read News
12 Stainless Steel Gears From QTC Features the Fairloc Integral Fastening System (October 6, 2008)
A new series of Modules 0.5, 0.8, and 1 spur gears from Quality Transmission Components features the patented Fairloc integral hub fast... Read News
13 Ikona Exec Featured in Online Broadcast (April 27, 2006)
Ikona Gear's CEO, Ray Polman, was featured live on Market News First on September 5. According to the company's press release,... Read News
14 Sunnen Introduces New Honing Features (January 9, 2013)
Sunnen Products introduces new servomotor and drive technology under the hood of its three primary vertical honing platforms, bringing ad... Read News