Spur Gears

GEAR TALK WITH CHUCK | 2018-07-03

Planetary Gears: Inside Information

The Story So Far

GEAR TALK WITH CHUCK | 2018-06-28

Suns and Planets

The first planetary drive I helped take apart had three stages of through hardened spur gears encased in a simple cast iron tube with plates on both ends. Both input and output shafts rotated on taper roller bearings, but everything else had simple bronze bushings.

GEAR TALK WITH CHUCK | 2018-05-31

Parsing the Fine Print

If my last posting prompted you to look at a copy of a material cert, you probably noticed that the cert has much more information on it than just ...

GEAR TALK WITH CHUCK | 2018-04-17

How Many Teeth Do You Want?

Designing gears is somewhat of a mathematical puzzle. You have lots of interconnected factors to play with in hopes of finding the “best” overall s...

GEAR TALK WITH CHUCK | 2018-04-05

In Search of True Helical Action

I was trained in the cult of the integer face contact ratio. A few adherents to this belief are still above ground, but the introduction of persona...

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 | 2018-02-01

Understanding Spur Gears

Spur gears have been around “forever.” That ancient astronomical device recovered from the Mediterranean Sea a few years ago shows the antiquity an...

GEAR TALK WITH CHUCK | 2018-01-30

Appreciating the Spur Gear

When the average civilian hears the word “gear,” if they think of mechanical things at all, they envision a big spur gear, perhaps in a clock or wi...

GEAR TALK WITH CHUCK | 2017-07-28

A New Quoting Model?

Anyone actually enjoy quoting? For such an important part of daily business the process of establishing prices to offer a customer seems universall...

TECHNICAL ARTICLES | 2017-06-01

Designing Very Strong Gear Teeth by Means of High Pressure Angles

The purpose of this paper is to present a method of designing and specifying gear teeth with much higher bending and surface contact strength (reduced bending and surface contact stresses). This paper will show calculation procedures, mathematical solutions and the theoretical background equations to do this.

GEAR TALK WITH CHUCK | 2016-12-06

It’s a 24/7/52 World

This curmudgeon recently got a good lesson on how the Internet has changed the world. My adult children have been trying to get...

TECHNICAL ARTICLES | 2015-06-01

Test Facility Simulation Results for Aerospace Loss-of-Lubrication of Spur Gears

Prior to receiving airworthiness certification, extensive testing is required during the development of rotary wing aircraft drive systems. Many of these tests are conducted to demonstrate the drive system’s ability to operate at extreme conditions, i.e. — beyond that called for in the normal to maximum power operating range.

TECHNICAL ARTICLES | 2013-05-01

Hybrid Gear Preliminary Results: Application of Composites to Dynamic Mechanical Components

Composite spur gears were designed, fabricated and tested at NASA Glenn Research Center. The composite web was bonded only to the inner and outer hexagonal features that were machined from an initially all-metallic aerospace quality spur gear. The hybrid gear was tested against an all-steel gear and against a mating hybrid gear. Initial results indicate that this type of hybrid design may have a dramatic effect on drive system weight without sacrificing strength.

EVENTS | 2012-05-01

Technical Calendar

The complete Technical Calendar from the May 2012 issue of Gear Technology.

TECHNICAL ARTICLES | 2012-03-01

The Relative Performance of Spur Gears Manufactured from Steel and PEEK

This paper seeks to compare the data generated from test rig shaft encoders and torque transducers when using steel-steel, steel-plastic and plastic-plastic gear combinations in order to understand the differences in performance of steel and plastic gears.

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.

FEATURE ARTICLES | 2011-08-01

Chiming in on Gear Noise: Three Experts Have their Say

It is said that “The squeaky wheel gets the grease.” Ok, but what about gear noise? We talked to three experts with considerable knowledge and experience in this area.

TECHNICAL ARTICLES | 2011-08-01

Manufacturing Method of Large-Sized Spiral Bevel Gears in Cyclo-Palloid System Using Multi-Axis Control and Multi-Tasking Machine Tool

In this article, the authors calculated the numerical coordinates on the tooth surfaces of spiral bevel gears and then modeled the tooth profiles using a 3-D CAD system. They then manufactured the large-sized spiral bevel gears based on a CAM process using multi-axis control and multi-tasking machine tooling. The real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected using the measured coordinates. Moreover, the gears were meshed with each other and the tooth contact patterns were investigated. As a result, the validity of this manufacturing method was confirmed.

TECHNICAL ARTICLES | 2008-11-01

A Further Study on High-Contact-Ratio Spur Gears in Mesh with Double-Scope Tooth Profile Modification

This paper will demonstrate that, unlike commonly used low-contact-ratio spur gears, high-contact-ratio spur gears can provide higher power-to-weight ratio, and can also achieve smoother running with lower transmission error (TE) variations.

TECHNICAL ARTICLES | 2007-08-01

True Bending Stress in Spur Gears

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.

INDUSTRY NEWS | 2006-04-11

Norton’s New Gear Grinding Wheels Increase Life of Parallel Axis Spur Gears

The new BRGg VPHS high speed grinding wheels from Saint Gobain are designed to reduce cycle times by increasing metal removal rates. The ...

INDUSTRY NEWS | 2005-02-13

REM Chemicals and Rosler GmbH Partner in Metal Finishing

REM Chemicals Inc.and Rosler GmbH developed a 20-year global marketing partnership for chemically-accelerated mass finishing processes, m...

TECHNICAL ARTICLES | 2004-11-01

Non-Standard Cylindrical Gears

Curved face width (CFW) spur gears are not popular in the gear industry. But these non-metallic gears have advantages over standard spur gears: higher contact ratio, higher tooth stiffness, and lower contact and bending stresses.

PRODUCT NEWS | 2003-05-01

Product News

Complete Product News for May/June 2003.

INDUSTRY NEWS | 2001-01-01

The Basics of Spiral Bevel Gears

This article also appears as Chapter 1 in the Gleason Corporation publication "Advanced Bevel Gear Technology." Gearing Principles in Cylindrical and Straight Bevel Gears The purpose of gears is to transmit motion and torque from one shaft to another. That transmission normally has to occur with a constant ratio, the lowest possible disturbances and the highest possible efficiency. Tooth profile, length and shape are derived from those requirements.

REVOLUTIONS | 1999-07-01

Revolutions

Welcome to Revolutions, the column that brings you the latest, most up-to-date and easy-to-read information about the people and technology of the gear industry.

EVENTS | 1997-03-01

Technical Calendar

Complete Technical Calendar for March/April 1997.

TECHNICAL ARTICLES | 1996-09-01

Tooth Modification and Spur Gear Tooth Strain

A major source of helicopter cabin noise (which has been measured at over 100 decibels sound pressure level) is the gear box. Reduction of this noise is a NASA and U.S. Army goal.

TECHNICAL ARTICLES | 1996-05-01

Generating Precision Spur Gears By Wire EDM

Over the past decade, the wire electrical discharge machine (EDM) has become an increasingly important tool for machining non-standard shapes. It has even been used to cut gears and gear cavities for plastic molds. While generally accepted as a quick and versatile method for cutting spur gears, the EDM gear has lacked the precision of a mechanically machined or ground gear. We suspected that many of the errors associated with these gears were caused by inexact setup procedures, poor tool path control and improper cutting parameters. We decided to test the potential for the wire EDM to make the most accurate gear possible.

TECHNICAL ARTICLES | 1994-07-01

Effect of Extended Tooth Contact on the Modeling of Spur Gear Transmissions

In some gear dynamic models, the effect of tooth flexibility is ignored when the model determines which pairs of teeth are in contact. Deflection of loaded teeth is not introduced until the equations of motion are solved. This means the zone of tooth contact and average tooth meshing stiffness are underestimated, and the individual tooth load is overstated, especially for heavily loaded gears. This article compares the static transmission error and dynamic load of heavily loaded, low-contact-ratio spur gears when the effect of tooth flexibility has been considered and when it has been ignored. Neglecting the effect yields an underestimate of resonance speeds and an overestimate of the dynamic load.

TECHNICAL ARTICLES | 1994-05-01

Designing Hardened & Ground Spur Gears to Operate With Minimum Noise

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?

TECHNICAL ARTICLES | 1994-05-01

Minimizing Backlash in Spur Gears

simplified equations for backlash and roll test center distance are derived. Unknown errors in measured tooth thickness are investigate. Master gear design is outlined, and an alternative to the master gear method is described. Defects in the test radius method are enumerated. Procedures for calculating backlash and for preventing significant errors in measurement are presented.

TECHNICAL ARTICLES | 1992-07-01

Grinding of Spur and Helical Gears

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.

TECHNICAL ARTICLES | 1991-11-01

A Rational Procedure for Designing Minimum-Weight Gears

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.

TECHNICAL ARTICLES | 1990-07-01

Transmission Errors and Bearing Contact of Spur, Helical, and Spiral Bevel Gears

An investigation of transmission errors and bearing contact of spur, helical, and spiral bevel gears was performed. Modified tooth surfaces for these gears have been proposed in order to absorb linear transmission errors caused by gear misalignment and to localize the bearing contact. Numerical examples for spur, helical, and spiral bevel gears are presented to illustrate the behavior of the modified gear surfaces with respect to misalignment and errors of assembly. The numerical results indicate that the modified surfaces will perform with a low level of transmission error in non-ideal operating environments.

TECHNICAL ARTICLES | 1990-01-01

Surface Fatigue Life on CBN and Vitreous Ground Carburized and Hardened AISA 9310 Spur Gears

Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9210 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temperature of 320 K (116 degree F), an outlet oil temperature of 350 K (170 degree F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

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.

PUBLISHER'S PAGE | 1989-01-01

Leonardo, the Engineer

These lines, interesting enough, are from the notebooks of an artist whose images are part of the basic iconography of Western culture. Even people who have never set foot in a museum and wouldn't know a painting by Corregio from a sculpture by Calder, recognize the Mona Lisa. But Leonardo da Vinci was much more than an artist. He was also a man of science who worked in anatomy, botany, cartography, geology, mathematics, aeronautics, optics, mechanics, astronomy, hydraulics, sonics, civil engineering, weaponry and city planning. There was little in nature that did not interest Leonardo enough to at least make a sketch of it. Much of it became a matter of lifelong study. The breadth of his interests, knowledge, foresight, innovation and imagination is difficult to grasp.

TECHNICAL ARTICLES | 1988-11-01

Basic Spur Gear Design

Primitive gears were known and used well over 2,000 years ago, and gears have taken their place as one of the basic machine mechanisms; yet, our knowledge and understanding of gearing principles is by no means complete. We see the development of faster and more reliable gear quality assessment and new, more productive manufacture of gears in higher materials hardness states. We have also seen improvement in gear applications and design, lubricants, coolants, finishes and noise and vibration control. All these advances push development in the direction of smaller, more compact applications, better material utilization and improved quietness, smoothness of operation and gear life. At the same time, we try to improve manufacturing cost-effectiveness, making use of highly repetitive and efficient gear manufacturing methods.

EVENTS | 1988-11-01

Technical Calendar

November 1-3. SME Gear Processing and Manufacturing Clinic, Sheraton Meridian, Indianapolis, IN. November 5-10. international Conference on Gearing, Zhengzhou, China

TECHNICAL ARTICLES | 1988-09-01

Crowned Spur Gears: Optimal Geometry and Generation

Involute spur gears are very sensitive to gear misalignment. Misalignment will cause the shift of the bearing contact toward the edge of the gear tooth surfaces and transmission errors that increase gear noise. Many efforts have been made to improve the bearing contact of misaligned spur gears by crowning the pinion tooth surface. Wildhaber(1) had proposed various methods of crowning that can be achieved in the process of gear generation. Maag engineers have used crowning for making longitudinal corrections (Fig. 1a); modifying involute tooth profile uniformly across the face width (Fig. 1b); combining these two functions in Fig. 1c and performing topological modification (Fig. 1d) that can provide any deviation of the crowned tooth surface from a regular involute surface. (2)

TECHNICAL ARTICLES | 1987-07-01

Longitudinal Load Distribution Factor for Straddle- and Overhang-Mounted Spur Gears

A pair of spur gears generally has an effective lead error which is caused, not only by manufacturing and assembling errors, but also by the deformations of shafts, bearings and housings due to the transmitted load. The longitudinal load distribution on a contact line of the teeth of the gears is not uniform because of the effective lead error.

TECHNICAL ARTICLES | 1987-01-01

Lubricant Jet Flow Phenomena in Spur and Helical Gears

In the gearing industry, gears are lubricated and cooled by various methods. At low to moderate speeds and loads, gears may be partly submerged in the lubricant which provides lubrication and cooling by splash lubrication. With splash lubrication, power loss increases considerably with speed. This is partially because of churning losses. It is shown that gear scoring and surface pitting can occur when the gear teeth are not adequately lubricated and cooled.

FEATURE ARTICLES | 1986-09-01

Tooth Strength Study of Spur Planet Gears

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.

FEATURE ARTICLES | 1986-01-01

Effect of Shot Peening on Surface Fatigue Life of Carburized and Hardened AISI 1910 Spur Gears

Gear surface fatigue endurance tests were conducted on two groups of 10 gears each of carburized and hardened AlSI 9310 spur gears manufactured from the same heat of material

TECHNICAL ARTICLES | 1985-05-01

Gear Tooth Scoring Design Considerations for Spur and Helical Gearing

High speed gearing, operating with low viscosity lubricants, is prone to a failure mode called scoring. In contrast to the classic failure modes, pitting and breakage, which generally take time to develop, scoring occurs early in the operation of a gear set and can be the limiting factor in the gear's power capability.

PUBLISHER'S PAGE | 1985-05-01

Notes From the Editors Desk

This issue, our sixth, marks the 1st Anniversary of GEAR TECHNOLOGY, The Journal of Gear Manufacturing.

TECHNICAL ARTICLES | 1985-03-01

Gear Grinding Techniques Parallel Axes Gears

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.

TECHNICAL ARTICLES | 1985-01-01

Computer Aided Design (CAD) of Forging and Extrusion Dies for the Production of Gears by Forming

Material losses and long production times are two areas of conventional spur and helical gear manufacturing in which improvements can be made. Metalforming processes have been considered for manufacturing spur and helical gears, but these are costly due to the development times necessary for each new part design. Through a project funded by the U.S. Army Tank - Automotive Command, Battelle's Columbus Division has developed a technique for designing spur and helical gear forging and extrusion dies using computer aided techniques.