From tiny beginnings, the AGMA Gear Expo is growing into a fine, strapping show. This year's effort, Gear Expo '89, "The Cutting Edge," will be bigger and better than ever. What started as a few tabletop exhibits in Chicago four years ago has now grown to a full-size, international exhibition at the David Lawrence Convention Center in Pittsburgh. With over 160 exhibitors, including major gear manufacturers and suppliers from around the world, this year's show promises to be a great success as well.

May 18-21. AGMA Annual Meeting, "The Changing World of Gears." Loews Ventana Canyon Resort, Tucson, AZ. July 12-14, 1989. ASM international Conference on Carburizing. Sheraton Hotel & Conference Center, Lakewood, CO. September 12-20, 1989. European Machine Tool Show, Hannover, West Germany.

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.

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)

Gears are currently run at high speed and under high load. It is a significant problem to develop lubricants and gears with high load-carrying capacity against scoring. The particles of molybdenum disulfide have been considered to increase the scoring resistance of the gears. The wear characteristics and the scoring resistance of the gears lubricated with MoS2 paste and MoS2 powder have been investigated. (1) However, there are few investigations on the performance of the gears coated with MoS2 film with respect to scoring.

Two major processes used for cutting gears, hobbing and shaping. This article describes advanced machine design and cutter materials for gear shaping.

The use of plastic gearing is increasing steadily in new products. This is due in part to the availability of recent design data. Fatigue stress of plastic gears as a function of diametral pitch, pressure angle, pitch line velocity, lubrication and life cycles are described based on test information. Design procedures for plastic gears are presented.

History comes around full circle. It is interesting to talk to gear manufacturers who service the defense, aerospace, automotive and computer industries and find that their sales, production and backlogs reflect excellent and, in some cases, record breaking business.