The seemingly simple process of placing a uniform chamfer on the face ends of spur and helical gears, at least for the aerospace industry, has never been a satisfactory or cost effective process.
I sat down to write this editorial about my father, Harold Goldstein, as he approached his 80th birthday in October. I had meant it to be a celebration of his nearly 65 years in the machine tool business. Unfortunately, on August 26, as I was working on it, my father passed away after a long battle with emphysema. This editorial has now become a memorial as well as a celebration.
The chamfering and deburring operations on gear teeth have become more important as the automation of gear manufacturing lines in the automotive industry have steadily increased. Quieter gears require more accurate chamfers. This operation also translates into significant coast savings by avoiding costly rework operations. This article discusses the different types of chamfers on gear teeth and outlines manufacturing methods and guidelines to determine chamfer sizes and angles for the product and process engineer.
Earlier this year, a relative of mine, Sidney Mandell, tragically passed away. I had the good fortune to serve with Sidney on the Board of Directors and the Executive Committee of the Machinery Dealers National Association (MDNA). Though he started before me, his MDNA career and mine overlapped for about 2 years. As I think back on the many things I learned form him, one of his favorite phrases keeps come to mind: "We walk in the footsteps of those who have gone before us."
In today's industrial marketplace, deburring and chamfering are no longer just a matter of cosmetics. The faster speeds at which transmissions run today demand that gear teeth mesh as smoothly and accurately as possible to prevent premature failure. The demand for quieter gears also requires tighter tolerances. New heat treating practices and other secondary gear operations have placed their own set of demands on manufacturers. Companies that can deburr or chamfer to these newer, more stringent specifications - and still keep costs in line - find themselves with a leg up on their competition.
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?