Involute

GEAR TALK WITH CHUCK | 2018-08-21

Gearbox Design: Refining the Study Layout

A critical step in designing a gearbox is refining the “study layout” and securing the necessary approvals so that detail design can begin. Althoug...

GEAR TALK WITH CHUCK | 2018-08-16

Gear Design: What is it Going to Cost?

You may not ev...

INDUSTRY NEWS | 2018-08-13

International Gear Conference 2018

Lyon, France. Mechanical transmission components such as gears, rolling element bearings, CVTs, belts, chains, etc. are present in every industrial...

GEAR TALK WITH CHUCK | 2018-05-10

What’s Your Angle?

Hulet self-unloader image courtesy of ASME. Interesting things happen when you start using “non-standard” gear geometry. As early as th...

GEAR TALK WITH CHUCK | 2018-05-08

Making Things Work

There is an old saying that if the only tool you have is a hammer, everything looks like a nail. Imagine that you are tasked by your employer to de...

GEAR TALK WITH CHUCK | 2018-04-25

The Long and Short of It

One of the problems with “tribal knowledge” is that the terminology can confuse those who are not fully immersed in that community. I have lost ...

GEAR TALK WITH CHUCK | 2018-02-22

If Only It Was That Simple

In my last blog we went over “pitch” descriptions for spur gears. Engineers being stubborn individuals, it has not been possible to reach a consens...

GEAR TALK WITH CHUCK | 2018-01-09

How to Begin?

So, you want to teach people about gears. It is a huge topic with many interesting and complicated facets to it. A person could spend their entire ...

GEAR TALK WITH CHUCK | 2017-08-31

Cost Reduction Ideas

A commentator recently asked for “real world” examples of how he could reduce costs and win more orders. Improved technology is often cited as the ...

GEAR TALK WITH CHUCK | 2017-01-19

Gears That Time Forgot

My consulting practice covers a very wide range of products — from 4-inch circular pitch mill stands to 180-NDP handheld medical devices — I see th...

FEATURE ARTICLES | 2016-03-01

Plastic Gearing Continues Converting the Unconverted

Plastic gears are everywhere today - throughout your car, at the oceans' lowest depths, in deep space. The question, when is a metal gear a candidate for plastic conversion, can be addressed in three words, i.e. what's the application?

TECHNICAL ARTICLES | 2015-06-01

The Basics of Gear Theory

Beginning with our June Issue, Gear Technology is pleased to present a series of full-length chapters excerpted from Dr. Hermann J. Stadtfeld’s latest scholarly — yet practical — contribution to the gear industry — Gleason Bevel Gear Technology. Released in March, 2014 the book boasts 365 figures intended to add graphic support of a better understanding and easier recollection of the covered material.

GEAR TALK WITH CHUCK | 2015-04-21

Play Through, Old Friend

One of the consequences of growing older is saying good bye to friends you have made along the way. Word reached me this week that one of the best ...

GEAR TALK WITH CHUCK | 2015-02-24

Why is this Stuff Still so Complicated?

[starbox] Much of my engineering practice is working with companies that design machines only once in a while. I enjoy working with the people on ...

GEAR TALK WITH CHUCK | 2015-01-29

Microgeometry

[starbox] Much of my design work involves “math modeling” gearsets to determine the lowest-cost components which will meet the requirements. Over ...

GEAR TALK WITH CHUCK | 2015-01-29

Feedback and Comments

[starbox] We are starting our second year of this blog and are pleased that it was named one of the Top 50 Design and Development Blogs on the Int...

FEATURE ARTICLES | 2015-01-01

Getting in Gear with the Chain of Innovations

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.

TECHNICAL ARTICLES | 2015-01-01

Non-Involute Gearing, Function and Manufacturing Compared to Established Gear Designs

Introduction The standard profile form in cylindrical gears is an involute. Involutes are generated with a trapezoidal rack — the basis for easy and production-stable manufacturing (Fig. 1).

GEAR TALK WITH CHUCK | 2014-11-13

A Good Waste of Time

GEAR TALK WITH CHUCK | 2014-10-07

Spamsters be Damned — We're Bloggin' Here

[starbox] The anticipated, two-way dialog for this blog has been hampered by persistent spammers trying to scam their way onto t...

FEATURE ARTICLES | 2014-09-01

Gear Manufacturer Benefits from CAM Initiatives and Advanced Manufacturing Technology

Multiple CAM initiatives at Snyder Industries are improving safety, quality and productivity for parts ranging from 50 to 5,000 lbs.

GEAR TALK WITH CHUCK | 2014-08-28

Specialization is for Insects

[starbox] The sports world was abuzz recently over a girl pitching her Little League team into the World Championship Tournament. For some this ...

TECHNICAL ARTICLES | 2014-08-01

First International Involute Gear Comparison

Measurement institutions of seven different countries — China, Germany, Japan, Thailand, Ukraine, United Kingdom and the U.S. — participated in the implementation of the first international comparison of involute gear measurement standards. The German metrology institute Physikalisch-Technische Bundesanstalt (PTB) was chosen as the pilot laboratory as well as the organizer. Three typical involute gear measurement standards provided by the PTB were deployed for this comparison: a profile, a helix and a pitch measurement standard. In the final analysis, of the results obtained from all participants, the weighted mean was evaluated as reference value for all 28 measured parameters. However, besides the measurement standards, the measured parameters, and, most importantly, some of the comparison results from all participants are anonymously presented. Furthermore, mishandling of the measurement standards as occurred during the comparison will be illustrated.

PRODUCT NEWS | 2014-03-01

Product News

The complete product news section from the March/April 2014 issue, featuring quick-change spline rolling racks from U.S. Gear Tools.

GEAR TALK WITH CHUCK | 2014-01-17

Gear Training Then and Now

[starbox] Blogging about gear training brings to mind the widely attended Illinois Tool Works Gear School that Bob Moderow operated on behalf of h...

ASK THE EXPERT | 2013-01-01

Measurement of Involute Master

Our experts tackle the topic of measuring involute masters, including both master gears and gear inspection artifacts.

INDUSTRY NEWS | 2013-01-01

The Involute Curve

Although gears can be manufactured using a wide variety of profiles, the involute curve is the most commonly used. Here are some of the basics.

FEATURE ARTICLES | 2012-06-01

Growing Pains - Renewables Hang on in Turbulent Energy Market

The turbines are still spinning. They’re spinning on large wind farms in the Great Plains, offshore in the Atlantic and even underwater where strong tidal currents offer new energy solutions. These turbines spin regularly while politicians and policy makers— tied up in discussions on tax incentives, economic recovery and a lot of finger pointing—sit idle. Much like the auto and aerospace industries of years past, renewable energy is coping with its own set of growing pains. Analysts still feel confident that clean energy will play a significant role in the future of manufacturing—it’s just not going to play the role envisioned four to five years ago.

EVENTS | 2011-11-01

IPTEX 2012 Preview

India is rapidly turning into a global manufacturing hub, thanks to the country’s manufacturing and engineering capabilities, vast pool of skilled expertise and its size. These qualities offer it a strategic advantage for the manufacturing segment. A large number of international companies in varied segments have already set up a manufacturing base in India and others are following suit. It only makes sense to bring this industry segment together under one roof to discuss the current trends and technology prevalent to the marketplace. IPTEX 2012 is scheduled from February 9–11, 2012 at the Bombay Exhibition Center in Mumbai, India.

TECHNICAL ARTICLES | 2010-06-01

Variation Analysis of Tooth Engagement and Load Sharing in Involute Splines

Involute spline couplings are used to transmit torque from a shaft to a gear hub or other rotating component. External gear teeth on the shaft engage an equal number of internal teeth in the hub. Because multiple teeth engage simultaneously, they can transmit much larger torques than a simple key and keyway assembly. However, manufacturing variations affect the clearance between each pair of mating teeth, resulting in only partial engagement.

TECHNICAL ARTICLES | 2010-01-01

Area of Existence of Involute Gears

This paper presents a unique approach and methodology to define the limits of selection for gear parameters. The area within those limits is called the “area of existence of involute gears” (Ref. 1). This paper presents the definition and construction of areas of existence of both external and internal gears. The isograms of the constant operating pressure angles, contact ratios and the maximum mesh efficiency (minimum sliding) isograms, as well as the interference isograms and other parameters are defined. An area of existence allows the location of gear pairs with certain characteristics. Its practical purpose is to define the gear pair parameters that satisfy specific performance requirements before detailed design and calculations. An area of existence of gears with asymmetric teeth is also considered.

TECHNICAL ARTICLES | 2009-07-01

Extending the Benefits of Elemental Gear Inspection

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.

TECHNICAL ARTICLES | 2008-07-01

The Kinematics of Conical Involute Gear Hobbing

Conical involute gears, also known as beveloid gears, are generalized involute gears that have the two flanks of the same tooth characterized by different base cylinder radii and different base helix angles.

PUBLISHER'S PAGE | 2007-01-01

What Do You Think

Publisher Michael Goldstein wants to know what you think about the 2007 redesign of Gear Technology magazine

TECHNICAL ARTICLES | 2005-11-01

Development of Conical Involute Gears (Beveloids) for Vehicle Transmissions

Conical involute gears (beveloids) are used in transmissions with intersecting or skewed axes and for backlash-free transmissions with parallel axes.

TECHNICAL ARTICLES | 2003-09-01

Solid Model Generation of Involute Cylindrical Gears

This paper presents approximate and accurate methods to generate solid models of involute cylindrical gears using Autodesk Inventor 3-D CAD software.

TECHNICAL ARTICLES | 2001-11-01

Profile Shift in External Parallel Axis Cylindrical Involute Gears

Early in the practice of involute gearing, virtually all gears were made with the teeth in a standard relationship to the reference pitch circle. This has the advantages that any two gears of the same pitch, helix angle and pressure angle can operate together, and that geometry calculations are relatively simple. It was soon realized, though, that there are greater advantages to be gained by modifying the relationship of the teeth to the reference pitch circle. The modifications are called profile shift.

TECHNICAL ARTICLES | 1998-11-01

The Basics of Gear Metrology and Terminology Part II

In the last section, we discussed gear inspection; the types of errors found by single and double flank composite and analytical tests; involute geometry; the involute cam and the causes and symptoms of profile errors. In this section, we go into tooth alignment and line of contact issues including lead, helix angles, pitch, pitchline runout, testing and errors in pitch and alignment.

TECHNICAL ARTICLES | 1998-09-01

The Basics of Gear Metrology and Terminology Part I

It is very common for those working in the gear manufacturing industry to have only a limited understanding of the fundamental principals of involute helicoid gear metrology, the tendency being to leave the topic to specialists in the gear lab. It is well known that quiet, reliable gears can only be made using the information gleaned from proper gear metrology.

TECHNICAL ARTICLES | 1998-05-01

Hobs & Form Relived Cutters: Common Sharpening Problems

Fig. 1 shows the effects of positive and negative rake on finished gear teeth. Incorrect positive rake (A) increase the depth and decreases the pressure angle on the hob tooth. The resulting gear tooth is thick at the top and thin at the bottom. Incorrect negative rake (B) decreases the depth and increases the pressure angle. This results in a cutting drag and makes the gear tooth thin at the top and thick at the bottom.

TECHNICAL ARTICLES | 1997-07-01

Involute Inspection Methods and Interpretation of Inspection Results

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.

TECHNICAL ARTICLES | 1997-05-01

Eddy Current Examination of Gear Systems

Nondestructive examination (NDE) of ferrous and nonferrous materials has long proved an effective maintenance and anomaly characterization tool for many industries. Recent research has expanded its applicability to include the inspection of large, open gear drives. Difficulties inherent in other NDE methods make them time-consuming and labor-intensive. They also present the user with the environmental problem of the disposal of used oil. The eddy current method addresses these problems.

EVENTS | 1997-03-01

Technical Calendar

Complete Technical Calendar for March/April 1997.

PUBLISHER'S PAGE | 1996-01-01

Plan Ahead

Indianapolis is a nice city. No. It's a great city for a convention. The facilities and the city are modern, clean and bright. The Convention Center is easy to get to by either car or plane, and its central location in the heart of town and the enclosed skyway system between it and major hotels put visitors close to amenities like restaurants, shopping and entertainment. The people are friendly and go out of their way to make visitors feel welcome.

FEATURE ARTICLES | 1996-01-01

Rebuilding a Metrology Infrastructure

The American Society of Mechanical Engineers (ASME) announced at Gear Expo '95 that a national service for the calibration of involute artifacts is now available at the Department of Energy's Y-12 Plant in Oak Ridge, TN.

TECHNICAL ARTICLES | 1995-07-01

How to Avoid Errors When Measuring Step Gears

There are problems in dimensional measurement that should be simple to solve with standard measuring procedures, but aren't. In such cases, using accepted practices may result in errors of hundreds of microns without any warning that something is wrong.

TECHNICAL ARTICLES | 1994-07-01

Computerized Hob Inspection & Applications of Inspection Results Part II

Flute Index Flute index or spacing is defined as the variation from the desired angle between adjacent or nonadjacent tooth faces measured in a plane of rotation. AGMA defines and provides tolerance for adjacent and nonadjacent flute spacing errors. In addition, DIN and ISO standards provide tolerances for individual flute variation (Fig. 1).

TECHNICAL ARTICLES | 1994-05-01

Computerized Hob Inspection & Applications of Inspection Results - Part I

Can a gear profile generated by the hobbing method be an ideal involute? In strictly theoretical terms - no, but in practicality - yes. A gear profile generated by the hobbing method is an approximation of the involute curve. Let's review a classic example of an approximation.

INDUSTRY NEWS | 1993-07-01

Gear Tip Chamfer and Gear Noise; Surface Measurement of Spiral Bevel Gear Teeth

Could the tip chamfer that manufacturing people usually use on the tips of gear teeth be the cause of vibration in the gear set? The set in question is spur, of 2.25 DP, with 20 degrees pressure angle. The pinion has 14 teeth and the mating gear, 63 teeth. The pinion turns at 535 rpm maximum. Could a chamfer a little over 1/64" cause a vibration problem?

INDUSTRY NEWS | 1992-07-01

Cutting Low-Pitch-Angle Bevel Gears, Worm Gears and The Oil Entry Gap

Question: Do machines exist that are capable of cutting bevel gear teeth on a gear of the following specifications: 14 teeth, 1" circular pitch, 14.5 degrees pressure angle, 4 degrees pitch cone angle, 27.5" cone distance, and an 2.5" face width?

TECHNICAL ARTICLES | 1991-09-01

Basic Gear Generation Designing the Teeth

The finished gear engineer, the man who is prepared for all emergencies, must first of all know the basic design principles. Next he must be well versed in all sorts of calculations which come under the heading of "involute trigonometry."

TECHNICAL ARTICLES | 1991-05-01

Surface Pitting Fatigue Life of Noninvolute Low-Contact-Ratio Gears

Spur gear endurance tests were conducted to investigate the surface pitting fatigue life of noninvolute gears with low numbers of teeth and low contact ratios for the use in advanced application. The results were compared with those for a standard involute design with a low number of teeth. The gear pitch diameter was 8.89 cm (3.50 in.) with 12 teeth on both gear designs. Test conditions were an oil inlet temperature of 320 K (116 degrees F), a maximum Hertz stress of 1.49 GPa (216 ksi), and a speed of 10,000 rpm. The following results were obtained: The noninvolute gear had a surface pitting fatigue life approximately 1.6 times that of the standard involute gear of a similar design. The surface pitting fatigue life of the 3.43-pitch AISI 8620 noninvolute gear was approximately equal to the surface pitting fatigue life of an 8-pitch, 28-tooth AISI 9310 gear at the same load, but at a considerably higher maximum Hertz stress.

INDUSTRY NEWS | 1991-03-01

Our Experts Discuss...

Question: I have just become involved with the inspection of gears in a production operation and wonder why the procedure specifies that four involute checks must be made on each side of the tooth of the gear being produced, where one tooth is checked and charted in each quadrant of the gear. Why is this done? These particular gears are checked in the pre-shaved, finish-shaved, and the after-heat-treat condition, so a lot of profile checking must be done.

TECHNICAL ARTICLES | 1990-11-01

The Involute Helicoid and The Universal Gear

A universal gear is one generated by a common rack on a cylindrical, conical, or planar surface, and whose teeth can be oriented parallel or skewed, centered, or offset, with respect to its axes. Mating gear axes can be parallel or crossed, non-intersecting or intersecting, skewed or parallel, and can have any angular orientation (See Fig.1) The taper gear is a universal gear. It provides unique geometric properties and a range of applications unmatched by any other motion transmission element. (See Fig.2) The taper gear can be produced by any rack-type tool generator or hobbing machine which has a means of tilting the cutter or work axis and/or coordinating simultaneous traverse and infeed motions.

TECHNICAL ARTICLES | 1990-09-01

Approximating an Involute Tooth Profile

On many occasions a reasonably approximate, but not exact, representation of an involute tooth profile is required. Applications include making drawings, especially at enlarged scale, and laser or EDM cutting of gears, molds, and dies used to produce gears. When numerical control (NC) techniques are to be used, a simple way to model an involute can make the NC programming task much easier.

TECHNICAL ARTICLES | 1990-09-01

Involute Splines

Engineering design requires many different types of gears and splines. Although these components are rather expensive, subject to direct wear, and difficult to replace, transmissions with gears and splines are required for two very simple reasons: 1) Motors have an unfavorable (disadvantageous) relation of torque to number of revolutions. 2)Power is usually required to be transmitted along a shaft.

TECHNICAL ARTICLES | 1989-03-01

Design of Internal Helical Gears

In principal, the design of internal helical gear teeth is the same as that for external helical gears. Any of the basic rack forms used for external helical gears may be applied to internal helical gears. The internal gear drive, however, has several limitations; not only all those which apply to external gears, but also several others which are peculiar to internal gears. As with external gears, in order to secure effective tooth action, interferences must be avoided. The possible interferences on an internal gear drive are as follows: 1. Involute interference. To avoid this, all of the working profile of the internal tooth must be of involute form.

INDUSTRY NEWS | 1989-01-01

Spur Gear Fundamentals

Gears are toothed wheels used primarily to transmit motion and power between rotating shafts. Gearing is an assembly of two or more gears. The most durable of all mechanical drives, gearing can transmit high power at efficiencies approaching 0.99 and with long service life. As precision machine elements gears must be designed.

TECHNICAL ARTICLES | 1988-11-01

Involutometry Illustrations

In our last issue, the labels on the drawings illustrating "Involutometry" by Harlan Van Gerpan and C. Kent Reece were inadvertently omitted. For your convenience we have reproduced the corrected illustrations here. We regret any inconvenience this may have caused our readers.

TECHNICAL ARTICLES | 1988-09-01

Involutometry

Involute Curve Fundamentals. Over the years many different curves have been considered for the profile of a gear tooth. Today nearly every gear tooth uses as involute profile. The involute curve may be described as the curve generated by the end of a string that is unwrapped from a cylinder. (See Fig. 1) The circumference of the cylinder is called the base circle.

VOICES | 1985-09-01

Industry Forum

Your May/June issue contains a letter from Edward Ubert of Rockwell International with some serious questions about specifying and measuring tooth thickness.

TECHNICAL ARTICLES | 1984-10-01

Scoring Load Capacity of Gears Lubricated with EP-Oils

The Integral Temperature Method for the evaluation of the scoring load capacity of gears is described. All necessary equations for the practical application are presented. The limit scoring temperature for any oil can be obtained from a gear scoring test.

TECHNICAL ARTICLES | 1984-10-01

Design of Involute Gear Teeth

In designing involute gear teeth, it is essential that the fundamental properties of the involute curve be clearly understood. A review of "the Fundamental Laws of the Involute Curve" found in last issue will help in this respect. It has previously been shown that the involute curve has its origin at the base circle. Its length, however, may be anything from zero at the origin or starting point on to infinity. The problem, therefore, in designing gear teeth, is to select that portion of the involute, which will best meet all requirements.

INDUSTRY NEWS | 1984-08-01

Functions of Gearing and Application of the Involute to Gear Teeth

Experience has proven that the involute provides the most satisfactory profile for spur and helical gear teeth, and fulfills the requirements for transmitting smooth, uniform angular motion.

INDUSTRY NEWS | 1984-05-01

The Process of Gear Shaving

Gear shaving is a free-cutting gear finishing operation which removes small amounts of metal from the working surfaces of the gear teeth. Its purpose is to correct errors in index, helical angle, tooth profile and eccentricity.

Involute

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