June/July 2011

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Feature Articles

An Emphasis on Accuracy
Meeting the many challenges of large gear inspection.

Wind Turbines: Clean Energy, but Energy Efficient
We talked energy efficiency with some major players in the lubricants industry— but with a focus on their products’ impact regarding energy efficiency of gears and gearboxes in wind turbines.

Gear Hobbing Technology Update
Q&A with Liebherr's Dr. Alois Mundt.

Technical Articles

Analysis and Testing of Gears with Asymmetric Involute Tooth Form and Optimized Fillet Form for Potential Application in Helicopter Main Drives
Gears with an asymmetric involute gear tooth form were analyzed to determine their bending and contact stresses relative to symmetric involute gear tooth designs, which are representative of helicopter main-drive gears.

Drive Line Analysis for Tooth Contact Optimization of High-Power Spiral Bevel Gears
In the majority of spiral bevel gears, spherical crowning is used. The contact pattern is set to the center of the active tooth flank and the extent of the crowning is determined by experience. Feedback from service, as well as from full-torque bench tests of complete gear drives, has shown that this conventional design practice leads to loaded contact patterns, which are rarely optimal in location and extent. Oversized reliefs lead to small contact area, increased stresses and noise, whereas undersized reliefs result in an overly sensitive tooth contact.

Hypoid Gears: Tribology Aspects in Angular Transmission Systems, Part VII
Hypoid gears are the paragon of gearing. To establish line contact between the pitches in hypoid gears, the kinematically correct pitch surfaces have to be determined based on the axoids. In cylindrical and bevel gears, the axoids are identical to the pitch surfaces and their diameter or cone angle can be calculated simply by using the knowledge about number of teeth and module or ratio and shaft angle. In hypoid gears, a rather complex approach is required to find the location of the teeth—even before any information about flank form can be considered. This article is part seven of an eight-part series on the tribology aspects of angular gear drives.


Are YOU Having Your Best Year Ever (Publishers Page)
Publisher Michael Goldstein discusses why some gear manufacturing companies are enjoying record years.

Gear Expo: Changing with the Times (Voices)
AGMA president Joe T. Franklin Jr. talks about how the AGMA Gear Expo has grown and changed since its beginnings as a table-top show in 1987.

Product News (Product News)
The complete Product News section from the June/July 2011 issue of Gear Technology.

PM Design Winners Announced at Powdermet 2011 (Events)
Design innovation, superior engineering properties, high end-market visibility and sustainability distinguish the winners of the 2011 Design Excellence awards, the annual powder metallurgy (PM) design competition sponsored by the Metal Powder Industries Federation.

Technical Calendar (Events)
The complete Technical Calendar from the June/July 2011 issue of Gear Technology.

Industry News (Industry News)
The complete Industry News section from the June/July 2011 issue of Gear Technology.

The Chevy Corvair (Addendum)
Relic of an era when quality was an afterthought.