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Articles About DIN 3967


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1 Gear Backlash Analysis of Unloaded Gear Pairs in Transmissions (June 2016)

A best practice in gear design is to limit the amount of backlash to a minimum value needed to accommodate manufacturing tolerances, misalignments, and deflections, in order to prevent the non-driving side of the teeth to make contact and rattle. Industry standards, such as ANSI/AGMA 2002 and DIN3967, provide reference values of minimum backlash to be used in the gear design. However, increased customers' expectations in vehicle noise eduction have pushed backlash and allowable manufacturing tolerances to even lower limits. This is especially true in the truck market, where engines are quieter because they run at lower speeds to improve fuel economy, but they quite often run at high torsional vibration levels. Furthermore, gear and shaft arrangements in truck transmissions have become more complex due to increased number of speeds and to improve efficiency. Determining the minimum amount of backlash is quite a challenge. This paper presents an investigation of minimum backlash values of helical gear teeth applied to a light-duty pickup truck transmission. An analytical model was developed to calculate backlash limits of each gear pair when not transmitting load, and thus susceptible to generate rattle noise, through different transmission power paths. A statistical approach (Monte Carlo) was used since a significant number of factors affect backlash, such as tooth thickness variation; center distance variation; lead; runout and pitch variations; bearing clearances; spline clearances; and shaft deflections and misalignments. Analytical results identified the critical gear pair, and power path, which was confirmed experimentally on a transmission. The approach presented in this paper can be useful to design gear pairs with a minimum amount of backlash, to prevent double flank contact and to help reduce rattle noise to lowest levels.

2 Tooth Thickness Tolerance and AGMA 2002-C16 (July 2019)

A reader asks: We are currently revising our gear standards and tolerances and a few questions with the new standard AGMA 2002-C16 have risen. Firstly, the way to calculate the tooth thickness tolerance seems to need a "manufacturing profile shift coefficient" that isn't specified in the standard; neither is another standard referred to for this coefficient. This tolerance on tooth thickness is needed later to calculate the span width as well as the pin diameter. Furthermore, there seems to be no tolerancing on the major and minor diameters of a gear.

3 Technological Potential and Performance of Gears Ground by Dressable CBN Tools (March/April 2014)

Dressable vitrified bond CBN grinding tools combine the advantages of other common tool systems in generating gear grinding. Yet despite those technological advantages, there is only a small market distribution of these grinding tools due to high tool costs. Furthermore, scant literature exists regarding generating gear grinding with dressable CBN. This is especially true regarding the influence of the grinding tool system on manufacturing-related component properties. The research objective of this report is to determine the advantages of dressable CBN tools in generating gear grinding.

4 No Compromising on Quality at Allison Transmission (July 2014)

Gleason 350GMS helps put higher quality, more reliable gears into its next-generation TC10 automatic transmission.

5 Industry News (July 2014)

The complete Industry News section from the July 2014 issue of Gear Technology.

6 Honing of Gears (August 2014)

The honing of gears - by definition - facilitates ease of operation, low noise and smoother performance in a transmission. Honing also contributes to reduced friction in the powertrain. Both the intense cutting (roughing process) as well as the functionally fine- finishing of transmission gears can be performed in one setup, on one machine.

7 The Pros and Cons of Fully Ground Root Fillets (August 2014)

For maximum life in carburized and ground gearing, I have been advised that fully grinding a radius into the root gives maximum resistance against fatigue failures. Others have advised that a hobbed and unground radius root form is best. Which is best, and why?

8 Setting Load Parameters for Viable Fatigue Testing of Gears in Powertrain Axles Part I: Single-Reduction Axles (August 2014)

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.

9 Who Is Afraid of Innovation (September/October 2014)

There are varying opinions as to what constitutes innovation, but in our industry and in the engineering world as a whole, we typically think of innovation as being the use of technologies different from those we use at the moment to do things better, faster and cheaper.

10 Simulation of Deviations in Hobbing and Generation Grinding (September/October 2014)

The hobbing and generation grinding production processes are complex due to tool geometry and kinematics. Expert knowledge and extensive testing are required for a clear attribution of cause to work piece deviations. A newly developed software tool now makes it possible to simulate the cutting procedure of the tool and superimpose systematic deviations on it. The performance of the simulation software is illustrated here with practical examples. The new simulation tool allows the user to accurately predict the effect of errors. With this knowledge, the user can design and operate optimal, robust gearing processes.

11 Keeping it in the Family (November/December 2014)

In this online-only exclusive, we present a profile of Jones Welding Company.

12 Making it in Mobile (November/December 2014)

"If it's broken, bring it on in." That's the advice offered by Roy Parker, president and owner of Jones Welding Company Inc.

13 Getting in Gear with the Chain of Innovations (January/February 2015)

At the dawn of the Industrial Revolution, so-called mechanics were tasked with devising the precise methods that would make mass production possible. The result was the first generation of machine tools, which in turn required improved tooling and production methods.

14 Prediction of Surface Zone Changes in Generating Gear Grinding (March/April 2015)

One process for hard finishing gears is generating gear grinding. Due to its high process efficiency, generating gear grinding has replaced other grinding processes such as profile grinding in batch production of small- and middle-sized gears. Yet despite the wide industrial application of generating gear grinding, the process design is based on experience along with time- and cost-intensive trials. The science-based analysis of generating gear grinding demands a high amount of time and effort, and only a few published scientific analyses exist. In this report a thermo-mechanical process model that describes influences on the surface zone in generating gear grinding is introduced.

15 Bevel Grinding Rolling Right Along (June 2015)

When Dr. Hermann J. Stadtfeld speaks, people tend to listen. Considered one of the world’s foremost experts on bevel gears, Stadtfeld, the vice president of bevel gear technology at Gleason, recently revealed several cutting-edge advancements that the company has been working on.

16 Gear Grinding is Getting Easier, Better, Faster, Stronger (June 2015)

Liebherr is well-known as one of the world’s largest privately owned companies — a titan in heavy industry specializing in cranes, trucks and mammoth earth moving and mining equipment.

17 Local Simulation of the Specific Material Removal Rate for Generating Gear Grinding (September/October 2015)

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.

18 Hard-Finishing Spiral Bevel Gears (March/April 2016)

Could you explain to me the difference between spiral bevel gear process face hobbing-lapping, face milling-grinding and Klingelnberg HPG? Which one is better for noise, load capacity and quality?

19 Industry News (May 2016)

Lastest news from around the industry.

20 The Comprehensive Gear Grind (June 2016)

Looking for some simple yet useful advice heading into IMTS 2016? Never second guess your machine tool investment. Flexibility is a mandatory requirement in gear manufacturing today. Accuracy, reliability and efficiency must improve with each new machine tool purchase. Innovation is always the end game. So it comes as no surprise that IMTS 2016 attendees will have plenty of gear grinding technologies to consider this fall.

21 PPD Wear Protection Treatment for Large Parts Opens New Horizons (March/April 2014)

Environmentally friendly, highly efficient and lasting a product's lifetime. With characteristics like this, Pulsed-Plasma Diffusion (PPD) technology from Oerlikon Balzers has established itself as an industry standard for the treatment of large automotive press tooling. Now the technology specialists are targeting new applications with this advanced process, offering an alternative to traditional hard-chrome processes.

22 Brad Foote and 3M Collaborate on Testing of Ground Parts (March/April 2014)

Cubitron II wheels are put to the test in this case study.

23 In Search of a Competitive Advantage (March/April 2014)

The grinding/abrasives market is rapidly changing, thanks to new technology, more flexibility and an attempt to lower customer costs. Productivity is at an all-time high in this market, and it’s only going to improve with further R&D. By the time IMTS 2014 rolls around this September, the gear market will have lots of new toys and gadgets to offer potential customers. If you haven’t upgraded any grinding/abrasives equipment in the last five years, now might be a good time to consider the investment.

24 Liebherr LFG Grinding Machine (May 2013)

This machine concept facilitates highly productive profile grinding for large workpieces. The range for external and internal gears comprises models for manufacturing workpieces up to 2,000 millimeters – for industrial gear units, wind power, and marine propulsion applications

25 IMTS 2012 Product Preview (September 2012)

Previews of manufacturing technology related to gears that will be on display at IMTS 2012.

26 Product News (October 2012)

The complete Product News section from the October 2012 issue of Gear Technology.

27 Gear Grinding Gets Integrated at IMTS 2012 (October 2012)

The latest machines, tooling and technology for gear grinding were featured at IMTS 2012.

28 CMM Gear Inspection (January/February 2013)

Mitutoyo offers capable, affordable and flexible gear inspection option via coordinate measuring machines and gear inspection software.

29 Product News (March/April 2013)

The complete Product News section from the March/April 2013 issue of Gear Technology.

30 Lean Shipping - Job Shop Lean (March/April 2013)

The shipping department is the closest to the customer, and its main objective is to maximize shipped orders every month. Our lean guru shows how to eliminate waste in the shipping department.

31 Workholding Options (March/April 2013)

Question: We manufacture some gears that require an axial face as a datum, as well as locating on the bore for centering. Other gears use only the bore for both axial and radial locating. What type of workholding is appropriate for each type of part? Is there workholding that will work for both types?

32 Industry News (March/April 2013)

The complete Industry News section from the March/April 2013 issue of Gear Technology.

33 Delivering Big Gears Fast (May 2013)

When a customer needed gears delivered in three weeks, here’s how Brevini Wind got it done.

34 The Next Transformation (March/April 2014)

Every so often manufacturing is jolted out of its inertia by a transformative technology – one that fundamentally changes not only the way products are made, but also the economics of the business.

35 If You Rebuild It, They Will Buy It (May 2013)

It’s been said that the best ideas are often someone else's. But with rebuilt, retrofitted, re-controlled or remanufactured machine tools, buyer beware and hold onto your wallet. Sourcing re-work vendors and their services can require just as much homework, if not necessarily dollars, as with just-off-the-showroom-floor machines.

36 Tooth Root Optimization of Powder Metal Gears - Reducing Stress from Bending and Transient Loads (June/July 2013)

This paper will provide examples of stress levels from conventional root design using a hob and stress levels using an optimized root design that is now possible with PM manufacturing. The paper will also investigate how PM can reduce stresses in the root from transient loads generated by abusive driving.

37 Liebherr Touts Technology at Latest Gear Seminar (June/July 2013)

For two days in Saline, Michigan, Liebherr's clients, customers and friends came together to discuss the latest gear products and technology. Peter Wiedemann, president of Liebherr Gear Technology Inc., along with Dr.-Ing. Alois Mundt, managing director, Dr.-Ing. Oliver Winkel, head of application technology, and Dr.-Ing. Andreas Mehr, technology development shaping and grinding, hosted a variety of informative presentations.

38 Product News (October 2013)

The complete Product News section from the October 2013 issue of Gear Technology.

39 The Art of Versatility - Grinding at Gear Expo and EMO (October 2013)

Whether you spent time at Gear Expo in Indianapolis or EMO in Hannover, there was certainly new technology attracting attention. Machine tools are faster, more efficient and can integrate numerous functions in a single setup. Grinding technology is turning science upside down and inside out with high-speed removal rates and increased throughput.

40 High Temperature Gear Materials (November/December 2013)

What gear material is suitable for high-temperature (350 – 550 degree C), high-vacuum, clean-environment use?

41 The XL Gears Project (January/February 2014)

Much of the existing guidelines for making large, high-performance gears for wind turbine gearboxes exhibit a need for improvement. Consider: the large grinding stock used to compensate for heat treatment distortion can significantly reduce manufacturing productivity; and, materials and manufacturing processes are two other promising avenues to improvement. The work presented here investigates quenchable alloy steels that, combined with specifically developed Case-hardening and heat treatment processes, exhibits reduced distortion and, in turn, requires a smaller grinding stock.

42 Industry News (January/February 2014)

The complete Industry News section from the January/February 2014 issue of Gear Technology.

43 Hail to the Quick-Change King (June 2016)

It's the year of the quick-change tool. From chucks to mandrels, workholding manufacturers across the industry are seeing a continuing trend from their customers: give us more quickchange.

44 Innovations for High Productivity Generating Grinding (June 2016)

In comparison to the visionary Industry 4.0 - or the Fourth Industrial Revolution - the machine tool industry can appear rather down-to-earth.

45 Bevel Gear Cutting Methods (June 2016)

THE FINAL CHAPTER This is the last in the series of chapters excerpted from Dr. Hermann J. Stadtfeld's Gleason Bevel Gear Technology - a book written for specialists in planning, engineering, gear design and manufacturing. The work also addresses the technical information needs of researchers, scientists and students who deal with the theory and practice of bevel gears and other angular gear systems. While all of the above groups are of course of invaluable importance to the gear industry, it is surely the students who hold the key to its future. And with that knowledge it is reassuring to hear from Dr. Stadtfeld of the enthusiastic response he has received from younger readers of these chapter installments.

46 Spin City (November/December 2018)

Grinding Wheel Technology Focuses on Speed, Efficiency and Time Savings

47 A Look at Intelligent Workholding and Toolholding (March/April 2018)

New Solutions Aim at Reducing Changeover Times and Improving Reliability

48 Effect of Non-Metallic Inclusions on Bending Fatigue Performance in High Strength 4140 Steel (March/April 2018)

Three samples of quenched and tempered 4140 steel, with varying levels of oxygen and sulfur, were submitted to a series of bending fatigue tests.

49 Cutting Down on Setup Time (June 2018)

With increasingly smaller returns from improving the speed of the actual gear grinding process, improving your setup time has become a primary way to keep improving efficiency. Here's the latest on how you can do that today.

50 Human Machine Interface (HMI) in Gear Manufacturing (June 2018)

"Documentation is not a Substitute for an Intuitive Interface." The author explores the development of modern controls for a CNC gear grinding machine.

51 Standard Samples for Grinder Burn Etch Testing (June 2018)

A different method to produce a sample that has a very consistent amount of thermal damage.

52 Influences of the Residual Stress Condition on the Load-Carrying Capacity of Case-Hardened Gears (August 2018)

Highly loaded gears are usually casehardened to fulfill the high demands on the load-carrying capacity. Several factors, such as material, heat treatment, or macro and micro geometry, can influence the load-carrying capacity. Furthermore, the residual stress condition also significantly influences load-carrying capacity. The residual stress state results from heat treatment and can be further modified by manufacturing processes post heat treatment, e.g. grinding or shot peening.

53 Influence of Different Manufacturing Processes on Properties of Surface-Densified PM Gears (September/October 2018)

The properties of both shot-peened and cold rolled PM gears are analyzed and compared. To quantify the effect of both manufacturing processes, the tooth root bending fatigue strength will be evaluated and compared to wrought gears.

54 Why Select Gear Grinding with cBN (November/December 2018)

Cubic Boron Nitride (cBN) abrasive wheels, which are a specially engineered abrasive grain referred to as a superabrasive, typically yield 2,200 - 2,500 parts per dress with one wheel lasting as long as four to six months.

55 Industry News (September/October 2017)

Bob Errichello retires from teaching, Siemens expands technical center, HBM Holdings acquires Schafer Industries, plus new hires and other industry news.

56 The Influence of a Grinding Notch on the Gear Bending Strength Rating (November/December 2018)

To achieve the requested quality, most gears today are ground. The usual grinding process includes treating the gear flank but disengaging before reaching the root rounding area. If the gear is premanufactured with a tool without protuberance, then at the position where the grinding tool retracts from the flank a grinding notch in the tooth root area is produced. Such a notch may increase the bending stresses in the root area, thus reducing the strength rating.

57 Gear Nitriding 2019 (March/April 2019)

A Conversation with Sabine Kreuzmayr of RĂĽbig

58 The Quick-Change Advantage (March/April 2019)

Workholding Systems Continue to Focus on Speed and Efficiency to Improve Machining Operations

59 Loading Upgrades (March/April 2019)

The latest advances in gear manufacturing automation all seem to revolve around a common theme: automated loading.

60 Application Factors (May 2019)

A reader asks: I'd like to know about the different approaches and factors considered while determining the value of Ka in regards to the DIN 3990 and AGMA standards.

61 Fine Grinding on Klingelnberg Bevel Gear Grinding Machines (June 2019)

One way to implement the growing performance requirements for transmissions is by optimizing the surface finish of the gearing. In addition to increasing the flank load capacity and the transmittable torque, this also allows for improvements in efficiency. On Oerlikon bevel gear grinding machines from Klingelnberg, fine grinding can be implemented efficiently in bevel gear production - even in an industrial serial process.

62 Product News (July 2019)

The complete Product News section from the July 2019 issue of Gear Technology.

63 Impact of Root Geometry Manufacturing Deviations from a Theoretical Hob Rack on Gear Bending Stress (August 2019)

This study emphasizes the importance of a closed-loop approach togear design and manufacturing to assure designed root fillet shapes are attained in production, and gears meet the design intent.

64 Friction Coefficient of Differently Treated Steel Surfaces (November/December 2017)

A reader asks about ion-nitride finished shafts and the proper friction coefficient to be used for calculations.

65 Gear Expo 2017 and ASM Heat Treat 2017 Booth Previews (September/October 2017)

The latest technology on display in Columbus, OH. October 24-26.

66 IMTS: Welcome to the Main Event (July 2016)

It's hard to think of a show more essential to attend than IMTS. It's the cornerstone event for the industry, the center of the universe for a week, the one show to rule them all.

67 Upgrading Your Toolbox (May 2017)

Manufacturers focus on tool design, materials, coating, machine tool options and cutting parameters.

68 Updating Modern Production Processes (August 2016)

Gear Technology interviews Scott Yoders of Liebherr about the latest gear machining technologies of relevance to automotive manufacturers.

69 Product News (September/October 2016)

News on the latest products in the industry.

70 Increased Tooth Bending Strength and Pitting Load Capacity of Fine-Module Gears (September/October 2016)

The common calculation methods according to DIN 3990 and ISO 6336 are based on a comparison of occurring stress and allowable stress. The influence of gear size on the load-carrying capacity is considered with the size factors YX (tooth root bending) and ZX (pitting), but there are further influences, which should be considered. In the following, major influences of gear size on the load factors as well as on the permissible tooth root bending and contact stress will be discussed.

71 Industry News (September/October 2016)

News From Around the Gear Industry

72 Locating Multiple Bore Diameters Via Hobbing (November/December 2016)

Attached photos (Figs. 1-2) show a bushing to locate one single bore. This will be used to locate one single bore diameter of a gear wheel. What is (the latest) technology for common clamping a bushing to locate multiple bore diameters in hobbing?

73 The Role of Natural Frequencies in Grinding Systems Vibration (November/December 2016)

Excessive machine tool vibration during a precision grinding operation can result in poor workpiece quality in the form of chatter, rough finishes, burn, etc. One possible reason for excessive vibration is directly associated with the relationship between natural frequencies of a machine tool system and the operating speed of the grinding wheel spindle.

74 Influence of Topography Deviations on the Psychoacoustic Evaluation of Ground Bevel Gears (November/December 2016)

In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to gear excitation. Within the past years, much investigation has shown that the noise emission can be attributed to quasi-static transmission error. Therefore, the transmission error can be used for a tooth contact analysis in the design process, as well as a characteristic value for quality assurance by experimental inspections.

75 Industry News (November/December 2016)

News from around the Industry

76 Gear Teeth as Bearing Surfaces (May 2017)

A reader wonders about gears where the tops of the teeth are the bearing surface, as used in spur gear differentials. Do they require any special construction or processing?

77 Efficient Hard Finishing of Asymmetric Tooth Profiles and Topological Modifications by Generating Grinding (August 2017)

In order to improve load-carrying capacity and noise behavior, gears usually have profile and lead modifications. Furthermore, in gears where a specified tooth-flank load application direction (for drive and coast flanks) is a design enhancement, or even compulsory, the asymmetric tooth profile is a further solution. Nowadays, many gears need to be hard finished. Continuous generating grinding offers a very high process efficiency, but is this process able to grind all modifications, especially asymmetric gears? Yes, it is!

78 Industry News (May 2017)

Faydor Litvin, 1914-2017; Michael Goldstein receives AGMA Distinguished Service Award.

79 Gear Grinding Today (June 2017)

New divisions, open houses and the continued rise of the Industrial Internet of Things - There's been a lot going on in gear grinding in the past year.

80 Anatomy of a Rebuild (June 2017)

Nuttall Gear taps Machine Tool Builders for shop floor upgrades.

81 Ground and Hobbed Globoidal Worm Sets (June 2017)

A reader wants to know: Are profile ground and hobbed globoidal worm sets better than multi-axis CNC generated globoidal worm gear sets for reduction of noise and vibration?

82 Twist Control Grinding (June 2017)

This paper introduces the latest process developments for the hard-finishing of gears, specifically in regard to controlling the so-called flank twist.

83 Surface Structure Shift for Ground Bevel Gears (June 2017)

Ground bevel and hypoid gears have a designed motion error that defines parts of their NVH behavior. The surface structure is defined by the hard finishing process.

84 MicroPulse and MicroShift for Ground Bevel Gearsets (July 2017)

Grinding of bevel and hypoid gears creates on the surface a roughness structure with lines that are parallel to the root. Imperfections of those lines often repeat on preceding teeth, leading to a magnification of the amplitudes above the tooth mesh frequency and their higher harmonics. This phenomenon is known in grinding and has led in many cylindrical gear applications to an additional finishing operation (honing). Until now, in bevel and hypoid gear grinding, a short time lapping of pinion and gear after the grinding operation, is the only possibility to change the surface structure from the strongly root line oriented roughness lines to a diffuse structure.

85 Hard Scudding - The Future Has Arrived (August 2017)

As the science of Scudding has rapidly evolved, the interest in the more advanced process Hard Scudding is increasing.

86 The Barkhausen Noise Inspection Method for Detecting Grinding Damage in Gears (November/December 2002)

When hardened steel components are ground, there is always the possibility of damage to the steel in the form of residual stress or microstructural changes. Methods for detecting this sort of damage have always had one or more drawbacks, such as cost, time, complexity, subjectivity, or the use of hazardous chemicals.

87 Parallel Axis Gear Grinding: Theory & Application (November/December 2000)

The goal of gear drive design is to transit power and motion with constant angular velocity. Current trends in gear drive design require greater load carrying capacity and increased service life in smaller, quieter, more efficient gearboxes. Generally, these goals are met by specifying more accurate gears. This, combined with the availability of user-friendly CNC gear grinding equipment, has increased the use of ground gears.

88 Design Against Tooth Interior Fatigue Fracture (November/December 2000)

In a modern truck, the gear teeth are among the most stressed parts. Failure of a tooth will damage the transmission severely. Throughout the years, gear design experience has been gained and collected into standards such as DIN (Ref. 1) or AGMA (Ref. 2). Traditionally two types of failures are considered in gear design: tooth root bending fatigue, and contact fatigue. The demands for lighter and more silent transmissions have given birth to new failure types. One novel failure type, Tooth Interior Fatigue Fracture (TIFF), has previously been described by MackAldener and Olsson (Refs. 3 & 4) and is further explored in this paper.

89 A Split Happened on the Way to Reliable, Higher-Volume Gear Grinding (September/October 2005)

Bevel gear manufacturers live in one of two camps: the face hobbing/lapping camp, and the face milling/grinding camp.

90 Generating Interchangeable 20-Degree Spur Gear Sets with Circular Fillets to Increase Load Carrying Capacity (July/August 2006)

This article presents a new spur gear 20-degree design that works interchangeably with the standard 20-degree system and achieves increased tooth bending strength and hence load carrying capacity.

91 Optimization of the Gear Profile Grinding Process Utilizing an Analogy Process (November/December 2006)

In order to grind gears burn-free and as productively as possible, a better understanding of the process is required.

92 Holroyd Launches New Gear Grinder (January/February 2005)

New machine promises DIN 2 accuracy and unique features at low cost.

93 Opportunities for Gear Grinders - Insights from the Machinery Front (July/August 2005)

Tom Lang of Kapp Technologies shares his views on the trends affecting ground gears.

94 Systematic Investigations on the Influence of Case Depth on the Pitting and Bending Strength of Case Carburized Gears (July/August 2005)

The gear designer needs to know how to determine an appropriate case depth for a gear application in order to guarantee the required load capacity.

95 Determining Power Losses in the Helical Gear Mesh (September/October 2005)

This article reviews mathematical models for individual components associated with power losses, such as windage, churning, sliding and rolling friction losses.

96 What to Know About Bevel Gear Grinding (September/October 2005)

Guidelines are insurance against mistakes in the often detailed work of gear manufacturing. Gear engineers, after all, can't know all the steps for all the processes used in their factories.

97 Methodology for Translating Single-Tooth Bending Fatigue Data to be Comparable to Running Gear Data (March/April 2008)

A method to extrapolate running gear bending strength data from STF results for comparing bending performance of different materials and processes.

98 American Wera Profilator Introduces Scudding Process (January/February 2008)

Rolled out at EMO 2007, the Scudding process is a continuous cutting operation that uses a tool design similar to a helical shaper cutter. It can be used for a wide range of gear applications...

99 HMC Lassos World's Largest Gear Grinder (June 2008)

Hofler Rapid 6000 Makes North American Debut at Highway Machine Company.

100 Guidelines for Modern Bevel Gear Grinding (August 2008)

This paper acknowledges the wide variety of manufacturing processes--especially in grinding--utlized in the production of bevel gears...

101 Influence of Grinding Burn on Pitting Capacity (August 2008)

This paper intends to determine the load-carrying capacity of thermally damaged parts under rolling stress. Since inspection using real gears is problematic, rollers are chosen as an acceptable substitute. The examined scope of thermal damage from hard finishing extends from undamaged, best-case parts to a rehardening zone as the worst case. Also, two degrees of a tempered zone have been examined.

102 Producing Profile and Lead Modifications in Threaded Wheel and Profile Grinding (January/February 2010)

Modern gearboxes are characterized by high torque load demands, low running noise and compact design. In order to fulfill these demands, profile and lead modifications are being applied more often than in the past. This paper will focus on how to produce profile and lead modifications by using the two most common grinding processes—threaded wheel and profile grinding. In addition, more difficult modifications—such as defined flank twist or topological flank corrections—will also be described in this paper.

103 Bending Fatigue, Impact and Pitting Resistance of Ausform-Finished PM Gears (June 2010)

The powder metal (P/M) process is making inroads in automotive transmission applications due to substantially lower costs of P/M-steel components for high-volume production, as compared to wrought or forged steel parts. Although P/M gears are increasingly used in powered hand tools, gear pumps and as accessory components in automotive transmissions, P/M-steel gears are currently in limited use in vehicle transmission applications. The primary objective of this project was to develop high-strength P/M-steel gears with bending fatigue, impact resistance and pitting fatigue performance equivalent to current wrought steel gears.

104 Grinding, Finishing and Software Upgrades Abound (March/April 2011)

Machine tool companies are expanding capabilities to better accommodate the changing face of manufacturing. Customers want smaller-sized equipment to take up less valuable floor space, multifunctional machines that can handle a variety of operations and easy set-up changes that offer simplified operation and maintenance.

105 Dearborn Precision Puts Dual Purpose Zeiss CMM to the Task (May 2011)

When parts you manufacture pass through numerous processes such as deep hole drilling, machining, hobbing and grinding, a CMM is essential when your customers require 100 percent in-process and final inspection.

106 Analysis and Testing of Gears with Asymmetric Involute Tooth Form and Optimized Fillet Form for Potential Application in Helicopter Main Drives (June/July 2011)

Gears with an asymmetric involute gear tooth form were analyzed to determine their bending and contact stresses relative to symmetric involute gear tooth designs, which are representative of helicopter main-drive gears.

107 Drake's Newest Thread Grinder Utilizes Robot Load-Unload System (July/August 2006)

The GS:TE-LM thread grinder from Drake Manufacturing is fitted with a robot load/unload system that provides maximum throughput for high-volume production of ground threads.

108 Asymmetric Teeth: Bending Stress Calculation (March/April 2007)

This article includes a brief summary of the characteristics of involute asymmetric teeth and the problems connected with the related bending tests.

109 CNC Controlled CBN Form Grinding (May/June 1984)

Borazon is a superabrasive material originally developed by General Electric in 1969. It is a high performance material for machining of high alloy ferrous and super alloy materials. Borazon CBN - Cubic Born Nitride - is manufactured with a high temperature, high pressure process similar to that utilized with man-made diamond. Borazon is, next to diamond, the hardest abrasive known; it is more than twice as hard as aluminum oxide. It has an extremely high thermal strength compared to diamond. It is also much less chemically reactive with iron, cobalt or nickel alloys.

110 Winds of Change in Profile Grinding (May/June 2004)

Recent breakthroughs in profile grinding software are helping Anderson Precision Gears and others meet wind power’s insatiable appetite for faster production of large, high-quality gears.

111 Effects of Gear Surface Parameters on Flank Wear (January/February 2009)

Non-uniform gear wear changes gear topology and affects the noise performance of a hypoid gear set. The aggregate results under certain vehicle driving conditions could potentially result in unacceptable vehicle noise performance in a short period of time. This paper presents the effects of gear surface parameters on gear wear and the measurement/testing methods used to quantify the flank wear in laboratory tests.

112 Innovative Concepts for Grinding Wind Power Energy Gears (June 2009)

This article shows the newest developments to reduce overall cycle time in grinding wind power gears, including the use of both profile grinding and threaded wheel grinding.

113 Gear Grinding 2003 (November/December 2003)

The benefits of ground gears are well known. They create less noise, transmit more power and have longer lives than non-ground gears. But grinding has always been thought of as an expensive process, one that was necessary only for aerospace or other high-tech gear manufacturing.

114 Bending Fatigue Tests of Helicopter Case Carburized Gears: Influence on Material, Design and Manufacturing Parameters (November/December 2009)

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.

115 An Investigation of the Influence of Shaft Misalignment on Bending Stresses of Helical Gears with Lead Crown (November/December 2008)

In this study, the combined influence of shaft misalignments and gear lead crown on load distribution and tooth bending stresses is investigated. Upon conclusion, the experimental results are correlated with predictions of a gear load distribution model, and recommendations are provided for optimal lead crown in a given misalignment condition.

116 Technological Fundamentals of CBN Bevel Gear Finish Grinding (November/December 1985)

The bevel gear grinding process, with conventional wheels, has been limited to applications where the highest level of quality is required.

117 Grinding Gears for Racing Transmissions (September/October 2009)

When you push 850 horsepower and 9,000 rpm through a racing transmission, you better hope it stands up. Transmission cases and gears strewn all over the racetrack do nothing to enhance your standing, nor that of your transmission supplier.

118 Dynamic Analysis of Straight and Involute Tooth Form (July/August 1985)

The effect of load speed on straight and involute tooth forms is studied using several finite-element models.

119 Cutting Edge Grinders Are Great - But How's Your Workholding (March/April 2009)

Capacity is key today, and the best way to ensure that you are squeezing every dime out of that new machine is to complement it with innovative workholding.

120 Tooth-Bending Effects in Plastic Spur Gears (September/October 2007)

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.

121 Grinding Induced Changes in Residual Stresses of Carburized Gears (March/April 2009)

This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory.

122 Gear Failure Analysis Involving Grinding Burn (January/February 2009)

When gears are case-hardened, it is known that some growth and redistribution of stresses that result in geometric distortion will occur. Aerospace gears require post case-hardening grinding of the gear teeth to achieve necessary accuracy. Tempering of the case-hardened surface, commonly known as grinding burn, occurs in the manufacturing process when control of the heat generation at the surface is lost.

123 Evaluation of Bending Strength of Carburized Gears (May/June 2004)

The aim of our research is to clearly show the influence of defects on the bending fatigue strength of gear teeth. Carburized gears have many types of defects, such as non-martensitic layers, inclusions, tool marks, etc. It is well known that high strength gear teeth break from defects in their materials, so it’s important to know which defect limits the strength of a gear.

124 How Are You Dealing with the Bias Error in Your Helical Gears (May 2009)

This paper initially defines bias error—the “twisted tooth phenomenon.” Using illustrations, we explain that bias error is a by-product of applying conventional, radial crowning methods to produced crowned leads on helical gears. The methods considered are gears that are finished, shaped, shaved, form and generated ground. The paper explains why bias error occurs in these methods and offers techniques used to limit/eliminate bias error. Sometimes, there may be a possibility to apply two methods to eliminate bias error. In those cases, the pros/cons of these methods will be reviewed.

125 Grinding and Abrasives (May/June 2004)

Flexibility and productivity are the keywords in today’s grinding operations. Machines are becoming more flexible as manufacturers look for ways to produce more parts at a lower cost. What used to take two machines or more now takes just one.

126 Gear Grinding Techniques Parallel Axes Gears (March/April 1985)

The fundamental purpose of gear grinding is to consistently and economically produce "hard" or "soft" gear tooth elements within the accuracy required by the gear functions. These gear elements include tooth profile, tooth spacing, lead or parallelism, axial profile, pitch line runout, surface finish, root fillet profile, and other gear geometry which contribute to the performance of a gear train.

127 Surface Damage Caused by Gear Profile Grinding and its Effects on Flank Load Carrying Capacity (September/October 2004)

Instances of damage to discontinuous form ground and surface-hardened gears, especially of large scale, have recently increased. This may be attributed partly to a faulty grinding process with negative effects on the surface zones and the surface properties.

128 True Bending Stress in Spur Gears (August 2007)

In this paper, an accurate FEM analysis has been done of the “true” stress at tooth root of spur gears in the function of the gear geometry. The obtained results confirm the importance of these differences.

129 Minimum Setup Time, Maximum Machining Capability (November/December 2011)

Hainbuch offers workholding solutions for United Gear.

130 Endurance Limit for Contact Stress in Gears (October/November 1984)

With the publishing of various ISO draft standards relating to gear rating procedures, there has been much discussion in technical papers concerning the various load modification factors. One of the most basic of parameters affecting the rating of gears, namely the endurance limit for either contact or bending stress, has not, however, attracted a great deal of attention.

131 The Design and Testing of a Low Noise Marine Gear (May/June 2000)

This article offers an overview of the practical design of a naval gear for combined diesel or gas turbine propulsion (CODOG type). The vibration performance of the gear is tested in a back-to-back test. The gear presented is a low noise design for the Royal Dutch Navy's LCF Frigate. The design aspects for low noise operation were incorporated into the overall gear system design. Therefore, special attention was paid to all the parameters that could influence the noise and vibration performance of the gearbox. These design aspects, such as tooth corrections, tooth loading, gear layout, balance, lubrication and resilient mounting, will be discussed.

132 The Advantages of Ion Nitriding Gears (November/December 1996)

When it comes to setting the standard for gear making, the auto industry often sets the pace. Thus when automakers went to grinding after hardening to assure precision, so did the machine shops that specialize in gearing. But in custom manufacturing of gears in small piece counts, post-heat treat grinding can grind away profits too.

133 CBN Gear Grinding - A Way to Higher Load Capacity (November/December 1993)

Because of the better thermal conductivity of CBN abrasives compared to that of conventional aluminum oxide wheels, CBN grinding process, which induces residual compressive stresses into the component, and possibly improves the subsequent stress behavior. This thesis is the subject of much discussion. In particular, recent Japanese publications claim great advantages for the process with regard to an increased component load capacity, but do not provide further details regarding the technology, test procedures or components investigated. This situation needs clarification, and for the this reason the effect of the CBN grinding material on the wear behavior and tooth face load capacity of continuously generated ground gears was further investigated.

134 Grinding Bevel Gears on Cylindrical Gear Grinding Machines (January/February 1994)

Power train designs which employ gears with cone angles of approximately 2 degrees to 5 degrees have become quite common. It is difficult, if not impossible, to grind these gears on conventional bevel gear grinding machines. Cylindrical gear grinding machines are better suited for this task. This article will provide an overview of this option and briefly introduce four grinding variation possibilities.

135 Generation of Helical Gears with New Surface Topology by Application of CNC Machines (January/February 1994)

Analysis of helical involute gears by tooth contact analysis shows that such gears are very sensitive to angular misalignment leading to edge contact and the potential for high vibration. A new topology of tooth surfaces of helical gears that enables a favorable bearing contact and a reduced level of vibration is described. Methods for grinding helical gears with the new topology are proposed. A TCA program simulating the meshing and contact of helical gears with the new topology has been developed. Numerical examples that illustrate the proposed ideas are discussed.

136 Investigation of Surface Layer and Wear Behavior of Nitrided Gear Drives (March/April 1994)

In this article we will characterize the nitride layers that are generated by different nitriding processes and compare their respective wear characteristics.

137 Designing Hardened & Ground Spur Gears to Operate With Minimum Noise (May/June 1994)

When designing hardened and ground spur gears to operate with minimum noise, what are the parameters to be considered? should tip and/or root relief be applied to both wheel and pinion or only to one member? When pinions are enlarged and he wheel reduced, should tip relief be applied? What are the effects on strength, wear and noise? For given ratios with enlarged pinions and reduced wheels, how can the gear set sized be checked or adjusted to ensure that the best combination has been achieved?

138 Multi-Metal Composite Gear-Shaft Technology (January/February 1995)

A research program, conducted in conjunction with a U.S. Army contract, has resulted in the development of manufacturing technology to produce a multi-metal composite gear/shaft representing a substantial weight savings compared to a solid steel component. Inertia welding is used to join a steel outer ring to a light-weight titanium alloy web and/or shaft through the use of a suitable interlayer material such as aluminum.

139 Gear Grinding Comes of Age (July/August 1995)

In the quest for ever more exacting and compact commercial gears, precision abrasives are playing a key production role - a role that can shorten cycle time, reduce machining costs and meet growing market demand for such requirements as light weights, high loads, high speed and quiet operation. Used in conjunction with high-quality grinding machines, abrasives can deliver a level of accuracy unmatched by other manufacturing techniques, cost-effectively meeting AGMA gear quality levels in the 12 to 15 range. Thanks to advances in grinding and abrasive technology, machining has become one of the most viable means to grind fast, strong and quiet gears.

140 Gear Grinding 1995 (July/August 1995)

Gear grinding is one of the most expensive and least understood aspects of gear manufacturing. But with pressures for reduced noise, higher quality and greater efficiency, gear grinding appears to be on the rise.

141 New Approaches to Nitriding (March/April 1997)

The process of nitriding has been used to case harden gears for years, but the science and technology of the process have not remained stagnant. New approaches have been developed which are definitely of interest to the gear designer. These include both new materials and new processing techniques.

142 1992 Marks Important Gear Design Milestone: Lewis Bending Strenth Equations Now 100 Years old (November/December 1992)

Columbus' first voyage to the Americas is not the only anniversary worthy of celebration this year. In 1892, on October 15, Wilfred Lewis gave an address to the Engineer's Club of Philadelphia, whose significance, while not as great as that of Columbus' voyage, had important results for the gearing community. In this address, Lewis first publicly outlined his formula for computing bending stress in gear teeth, a formula still in use today.

143 Profile Grinding Gears From The Solid - Is It Practical (May/June 1997)

It isn't for everyone, but... Within the installed base of modern CNC gear profile grinding machines (approximately 542 machines worldwide), grinding from the solid isn't frequent, but a growing number of gear profile grinder users are applying it successfully using CBN-plated wheels.

144 CNC Gear Grinding Methods (May/June 1997)

Grinding in one form or another has been used for more than 50 years to correct distortions in gears caused by the high temperatures and quenching techniques associated with hardening. Grinding improves the lead, involute and spacing characteristics. This makes the gear capable of carrying the high loads and running at the high pitch line velocities required by today's most demanding applications. Gears that must meet or exceed the accuracy requirements specified by AGMA Quality 10-11 or DIN Class 6-7 must be ground or hard finished after hear treatment.

145 Thermal Effects on CMMs (September/October 1997)

The trend toward moving coordinate measuring machines to the shop floor to become an integral part of the manufacturing operations brings real time process control within the reach of many companies. Putting measuring machines on the shop floor, however, subjects them to harsh environmental conditions. Like any measuring system, CMMs are sensitive to any ambient condition that deviates from the "perfect" conditions of the metrology lab.

146 Gear Crack Propagation Investigations (November/December 1997)

A common design goal for gears in helicopter or turboprop power transmission is reduced weight. To help meet this goal, some gear designs use thin rims. Rims that are too thin, however, may lead to bending fatigue problems and cracks. The most common methods of gear design and analysis are based on standards published by the American Gear Manufacturers Association. Included in the standards are rating formulas for gear tooth bending to prevent crack initiation (Ref. 1). These standards can include the effect of rim thickness on tooth bending fatigue (Ref 2.). The standards, however, do not indicate the crack propagation path or the remaining life once a crack has started. Fracture mechanics has developed into a useful discipline for predicting strength and life of cracked structures.

147 Hard Gear Finishing With CBN-Basic Considerations (May/June 1998)

For over 50 years, grinding has been an accepted method of choice for improving the quality of gears and other parts by correcting heat treat distortions. Gears with quality levels better than AGMA 10-11 or DIN 6-7 are hard finished, usually by grinding. Other applications for grinding include, but are not limited to, internal/external and spur/helical gear and spline forms, radius forms, threads and serrations, compressor rotors, gerotors, ball screw tracks, worms, linear ball tracks, rotary pistons, vane pump rotators, vane slots, and pump spindles.

148 Calculating Spur and Helical Gear Capacity with ISO 6336 (November/December 1998)

This is the third article in a series exploring the new ISO 6336 gear rating standard and its methods of calculation. The opinions expressed herein are htose of the author as an individual. They do not represent the opinions of any organization of which he is a member.

149 Selection of the Optimal Parameters of the Rack-Tool to Ensure the Maximum Gear Tooth Profile Accuracy (January/February 1999)

An analysis of possibilities for the selection of tool geometry parameters was made in order to reduce tooth profile errors during the grinding of gears by different methods. The selection of parameters was based on the analysis of he grid diagram of a gear and a rack. Some formulas and graphs are presented for the selection of the pressure angle, module and addendum of the rack-tool. The results from the grinding experimental gears confirm the theoretical analysis.

150 Gear Grinding With Dish Wheels (September/October 1999)

The grinding of gears with dish wheels (Maad type grinding machines) is widely viewed as the most precise method of gear grinding because of the very short and simple kinematic links between the gear and the tool, and also because the cutting edges of the wheels represent planar surfaces. However, in this grinding method, depending on the parameters of the gears and one of the adjustments (such as the number of teeth encompassed by the grinding wheels), so-called overtravel at the tip or at the root of the teeth being ground generally occurs. When this happens, machining with only one wheel takes place. As a result, the profile error and the length of the generating path increases while productivity decreases.

151 CNC Bevel Gear Generators and Flared Cup Gear Grinding (July/August 1993)

New freedom of motion available with CNC generators make possible improving tooth contact on bevel and hypoid gears. Mechanical machines by their nature are inflexible and require a special mechanism for every desired motion. These mechanisms are generally exotic and expensive. As a result, it was not until the introduction of CNC generators that engineers started exploring motion possibilities and their effect on tooth contact.

152 Investigation of the Strength of Gear Teeth (November/December 1992)

To mechanical engineers, the strength of gear teeth is a question of constant recurrence, and although the problem to be solved is quite elementary in character, probably no other question could be raised upon which such a diversity of opinion exists, and in support of which such an array of rules and authorities might be quoted. In 1879, Mr. John H. Cooper, the author of a well-known work on "Belting," made an examination of the subject and found there were then in existence about forty-eight well-established rules for horsepower and working strength, sanctioned by some twenty-four authorities, and differing from each other in extreme causes of 500%. Since then, a number of new rules have been added, but as no rules have been given which take account of the actual tooth forms in common use, and as no attempt has been made to include in any formula the working stress on the material so that the engineer may see at once upon what assumption a given result is based, I trust I may be pardoned for suggesting that a further investigation is necessary or desirable.

153 Lower Grinding Costs and Better Workpiece Quality by High Performance Grinding with CBN Wheels (January/February 1986)

A considerable improvement in the performance of the machining of hard to grind materials can be achieved by means of CBN wheels.

154 Enhanced Product Performance--Through CBN Grinding (September/October 1988)

Modern manufacturing processes have become an ally of the product designer in producing higher quality, higher performing components in the transportation industry. This is particularly true in grinding systems where the physical properties of CBN abrasives have been applied to improving cycle times, dimensional consistency, surface integrity and overall costs. Of these four factors, surface integrity offers the greatest potential for influencing the actual design of highly stressed, hardened steel components.

155 Selection of Material and Compatible Heat Treatments for Gearing (May/June 1986)

The manufacturing process to produce a gear essentially consist of: material selection, blank preshaping, tooth shaping, heat treatment, and final shaping. Only by carefully integrating of the various operations into a complete manufacturing system can an optimum gear be obtained. The final application of the gear will determine what strength characteristics will be required which subsequently determine the material and heat treatments.

156 A Wheel Selection Technique for Form Gear Grinding (May/June 1986)

Until recently, form gear grinding was conducted almost exclusively with dressable, conventional abrasive grinding wheels. In recent years, preformed, plated Cubic Boron Nitride (CBN) wheels have been introduced to this operation and a considerable amount of literature has been published that claim that conventional grinding wheels will be completely replaced in the future. The superior machining properties of the CBN wheel are not disputed in this paper.

157 Tooth Strength Study of Spur Planet Gears (September/October 1986)

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.

158 Mirror Finishing of Tooth Surfaces Using A Trial Gear Grinder With Cubic-Boron-Nitride Wheel (November/December 1986)

In conventional gear grinders, grinding wheels with Alundum grains and a hardness of about 2000 HV have been used for finishing steel gears with hardnesses up to about 1000HV. In this case, the accuracy of the gears ground is greatly affected by wear of the grinding wheel because the difference in hardness is comparatively small when the gears are fully hardened.

159 Stopping the Great American Giveaway (January/February 1987)

Inviting an American shipbuilding industry official to discuss the subject of meeting foreign competition is like inviting Jackie Gleason to speak on dieting. I am painfully aware of the commercial shipbuilding industry situation. Let me tell you a little about it.

160 Influence of Geometrical Parameters on the Gear Scuffing Criterion - Part I (March/April 1987)

The load capacity rating of gears had its beginning in the 18th century at Leiden University when Prof. Pieter van Musschenbroek systematically tested the wooden teeth of windmill gears, applying the bending strength formula published by Galilei one century earlier. In the next centuries several scientists improved or extended the formula, and recently a Draft International Standard could be presented.

161 Hard Gear Finishing (March/April 1988)

Hard Gear Finishing (HGF), a relatively new technology, represents an advance in gear process engineering. The use of Computer Numerical Controlled (CNC) equipment ensures a high precision synchronous relationship between the tool spindle and the work spindle as well as other motions, thereby eliminating the need for gear trains. A hard gear finishing machine eliminates problems encountered in two conventional methods - gear shaving, which cannot completely correct gear errors in gear teeth, and gear rolling, which lacks the ability to remove stock and also drives the workpiece without a geared relationship to the master rolling gear. Such a machine provides greater accuracy, reducing the need for conventional gear crowning, which results in gears of greater face width than necessary.

162 Computer-Aided Design of the Stress Analysis of an Internal Spur Gear (May/June 1988)

Although there is plenty of information and data on the determination of geometry factors and bending strength of external gear teeth, the computation methods regarding internal gear design are less accessible. most of today's designs adopt the formulas for external gears and incorporate some kind of correction factors for internal gears. However, this design method is only an approximation because of the differences between internal gears and external gears. Indeed, the tooth shape of internal gears is different from that of external gears. One has a concave curve, while the other has a convex curve.

163 Fillet Geometry of Ground Gear Teeth (January/February 1989)

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.

164 Grinding of Spur and Helical Gears (July/August 1992)

Grinding is a technique of finish-machining, utilizing an abrasive wheel. The rotating abrasive wheel, which id generally of special shape or form, when made to bear against a cylindrical shaped workpiece, under a set of specific geometrical relationships, will produce a precision spur or helical gear. In most instances the workpiece will already have gear teeth cut on it by a primary process, such as hobbing or shaping. There are essentially two techniques for grinding gears: form and generation. The basic principles of these techniques, with their advantages and disadvantages, are presented in this section.

165 Hard Finishing and Fine Finishing Part 1 (September/October 1989)

Profitable hard machining of tooth flanks in mass production has now become possible thanks to a number of newly developed production methods. As used so far, the advantages of hard machining over green shaving or rolling are the elaborately modified tooth flanks are produced with a scatter of close manufacturing tolerances. Apart from an increase of load capacity, the chief aim is to solve the complex problem of reducing the noise generation by load-conditioned kinematic modifications of the tooth mesh. In Part II, we shall deal with operating sequences and machining results and with gear noise problems.

166 Gear Grinding Fundeamentals (September/October 1989)

This article deals with certain item to be taken into consideration for gear grinding, common problems that arise in gear grinding and their solutions. The discussion will be limited to jobbing or low-batch production environments, where experimental setup and testing is not possible for economic and other reasons.

167 Hard Finishing and Fine Finishing Part 2 (November/December 1989)

After shaping or hobbing, the tooth flanks must be either chamfered or duburred. Here it is paramount that the secondary burr produced will not be formed into the flank, but to the face of the gear, because during hardening, the secondary burr will straighten up and, due to its extreme hardness, will lead to excessive tool wear.

168 The Effects of Surface Hardening on the Total Gear Manufacturing System (January/February 1991)

Carburized and hardened gears have optimum load-carrying capability. There are many alternative ways to produce a hard case on the gear surface. Also, selective direct hardening has some advantages in its ability to be used in the production line, and it is claimed that performance results equivalent to a carburized gear can be obtained. This article examines the alternative ways of carburizing, nitriding, and selective direct hardening, considering equipment, comparative costs, and other factors. The objective must be to obtain the desired quality at the lowest cost.

169 Influence of CBN Grinding on Quality and Endurance of Drive Train Components (January/February 1991)

The merits of CBN physical characteristics over conventional aluminum oxide abrasives in grinding performance are reviewed. Improved surface integrity and consistency in drive train products can be achieved by the high removal rate of the CBN grinding process. The influence of CBN wheel surface conditioning procedure on grinding performance is also discussed.

170 Hard Finishing By Conventional Generating and Form Grinding (March/April 1991)

The quality of a gear and its performance is determined by the following five parameters, which should be specified for each gear: Pitch diameter, involute form, lead accuracy, spacing accuracy, and true axis of rotation. The first four parameters can be measured or charted and have to be within tolerance with respect to the fifth. Pitch diameter, involute, lead, and spacing of a gear can have master gear quality when measured or charted on a testing machine, but the gear might perform badly if the true axis of rotation after installation is no longer the same one used when testing the gear.

171 A Rational Procedure for Designing Minimum-Weight Gears (November/December 1991)

A simple, closed-form procedure is presented for designing minimum-weight spur and helical gearsets. The procedure includes methods for optimizing addendum modification for maximum pitting and wear resistance, bending strength, or scuffing resistance.

172 Gear Hardness Technology (March/April 1992)

In a very general sense, increasing the hardness of a steel gear increases the strength of the gear. However, for each process there is a limit to its effectiveness. This article contains background information on each of the processes covered. In each section what is desired and what is achievable is discussed. Typical processes are presented along with comments on variables which affect the result. By reviewing the capabilities and processes, it is possible to determine the limits to each process.

173 A Precise Prediction of the Tooth Root Stresses for Involute External Gears with Any Fillet Geometry under Consideration of the Exact Meshing Condition (September/October 2019)

This paper shows a method to calculate the occurring tooth root stress for involute, external gears with any form of fillets very precisely within a few seconds.