Recently I had the pleasure of having dinner with Frank Sinatra, Jr. He was here in Chicago for a benefit concert for Roosevelt University (my wife is co-chairperson of the benefit). Our conversation ranged over a wide variety of subjects, including a small gem of an HBO television movie, "Truman" with Gary Sinise in the title role.
This book is written for those among us, with or without a technical background, who have an occasional need to use, purchase or specify gears. The author assumes an audience that is not made up of experienced gear designers, but of people who do need to have a basic understanding of the criteria used by the designer. The subjects covered include not only the gears themselves, but their manufacturing methods, the systems that contain them and the terms used to describe them.
For many years, when gear engineers have been confronted with tough problems either in the field or on the drawing board, one of the inevitable suggestions has been, "Ask Darle Dudley," or "Check the Dudley book." That's not surprising. With more than fifty years' experience in gear design and credits for five books (with translations in French, German, Spanish and Italian), numerous papers, lectures, and patents, and a worldwide reputation as a gear expert, Darle Dudley's position as one of the men to ask when dealing with knotty gear problems is unassailable.
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.
When designing a gear set, engineers usually want the teeth of the gear (Ng) and the pinion (Np) in a "hunting" mesh. Such a mesh or combination is defined as one in which the pinion and the gear do not have any common divisor by a prime number. If a mesh is "hunting," then the pinion must make Np x Ng revolutions before the same pinion tooth meshes with the same gear space. It is often easy to determine if a mesh is hunting by first determining if both the pinion and the gear teeth are divisible by 2,3,5,7,etc. (prime numbers). However, in this age of computerization, how does one program the computer to check for hunting teeth? A simple algorithm is shown below.
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.
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.
When you need totally useless information about gears, you can turn with confidence to the pages of Addendum, where we scour the globe for the obscure, the unusual and the ridiculous (the latter being or forte.)