In Part I differences in pitting ratings between AGMA 218, the draft ISO standard 6336, and BS 436:1986 were examined. In this part bending strength ratings are compared. All the standards base the bending strength on the Lewis equation; the ratings differ in the use and number of modification factors. A comprehensive design survey is carried out to examine practical differences between the rating methods presented in the standards, and the results are shown in graphical form.
The authors of last issue's article comparing AGMA, ISO and BS methods for Pitting Resistance Ratings are commended. Trying to compare various methods of rating gears is like hitting a moving target in a thick forest. The use of different symbols, presentations, terminology, and definitions in these standards makes it very difficult. But the greatest problem lies with the authors' use of older versions of these documents. ISO drafts and AGMA standards have evolved at the same time their work was accomplished and edited.
A study of AGMA 218, the draft ISO standard 6336, and BS 436: 1986 methods for rating gear tooth strength and surface durability for metallic spur and helical gears is presented. A comparison of the standards mainly focuses on fundamental formula and influence factors, such as the load distribution factor, geometry factor, and others. No attempt is made to qualify or judge the standards other than to comment on the facilities or lack of them in each standard reviewed. In Part I a comparison of pitting resistance ratings is made, and in the subsequent issue, Part II will deal with bending stress ratings and comparisons of designs.
Six years ago this month, the very first issue of Gear Technology, the Journal of Gear Manufacturing, went to press. The reason for starting the publication was a straightforward one: to provide a forum for the presentation of the best technical articles on gear-related subjects from around the world. We wanted to give our readers the information they need to solve specific problems, understanding new technologies, and to be informed about the latest applications in gear design and manufacturing. The premise behind Gear Technology was also a straightforward one: the better informed our readers were about the technology, the more competitive they and their companies would be int he world gear market.
In 1985 a new tooling concept for high volume gear production was introduced to the gear manufacturing industry. Since then this tool, the wafer shaper cutter, has proven itself in scores of applications as a cost-effective, consistent producer of superior quality parts. This report examines the first high-production installation at the plant of a major automotive supplies, where a line of twenty shapers is producing timing chain sprockets.
It is often easy for those outside of the gear industry to get the impression that nothing is changing in our business. After all, all illustrated bimonthly by the covers of this very journal the making of gears has been with us for centuries. However, nothing could be further from the truth.
For the last few years, the market has been tough for the U.S. gear industry. That statement will cause no one any surprise. The debate is about what to do. One sure sign of this is the enormous attention Congress and the federal government are now placing on "competitiveness."
A change has taken place within the industry that is going to have an enormous effect on the marketing, sales, and purchasing of gear manufacturing and related equipment. This change was the American Gear Manufacturers' Association, first biennial combination technical conference and machine tool minishow.
October 5-8, 1986 AGMA Fall technical Conference & Gearing Exhibit
September 17-19, 1986 Ohio State University Gear Noise Seminar
November 11-13, 1986 SME Gear Processing and Manufacturing Clinic
November 19-21, 1986 Seminar: Gear System Design for Minimum Noise