Noted gear consultant and gear educator Ray Drago is fond of saying that a consultant’s best answers usually start with “it depends.” Those of you have had the opportunity to attend one of Ray’s seminars are smiling right now. If you haven’t availed yourself of Ray’s classes (or other AGMA educational products) I urge you to do so sooner, not later. I was blessed to meet and learn from some of the best gear engineers over my career; sadly many of them are no longer available for consultation.
Which is a real shame for our profession, because these giants of our trade were instrumental in getting the industry to where it is today. They also, to use the vernacular, knew “where the bodies were buried.” Engineering, being an applied science, requires us to move forward with new materials and techniques BEFORE we have full scientific understanding of the factors involved.
This costs our employers and customers a great deal. Because we don’t know how grind steps affect tooth strength, we throw out parts with steps or spend lots of machine hours reworking them. Because we don’t have a direct relationship between our allowable stress numbers and standard laboratory sample tests, we can’t use the full potential of our gears.
Progress is being made in some areas, but it takes a long time to be widely shared. Legal and commercial concerns are part of the delay but a larger issue is the lack of corporate support for basic gear research. There just isn’t the will to do “science” at the company level, and our university-based gear research centers seem too far removed from the needs of the industrial gear community.
These are some of the topics I wish we knew more about:
- Grind steps in the root
- The connection between traditional material properties (tensile, yield, impact, etc.) and allowable gear loads
- The relationship between forging properties (reduction ratio, grain flow) and allowable stress
- The validity of Reliability factors as presently used
- A method of evaluating the size factor
Feel free to tack your topics on to my list. One of the things I love about the gear trade is that after several thousand years we still have interesting things to learn about.