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August 2013

Publisher's Page

Gear Expo - Gear Buyers Bonanza

If you’re reading this magazine, there's a good chance you're somehow involved in the design, specification or purchase of gears or geared products. As such, I urge you to make plans now to attend Gear Expo in Indianapolis, September 17-19

Technical Articles

Preventing Fretting Fatigue in Blade Dovetail Roots by Modifying Geometry of Contact Surfaces

Dovetails, gears and splines have been widely used in aero engines where fretting is an important failure mode due to loading variation and vibration during extended service. Failure caused by fretting fatigue becomes a prominent issue when service time continues beyond 4,000 hours. In some cases, microslip at the edge of a contact zone can reduce the life by as much as 40–60 percent.

Brush DC Motor Runs Along

Everything started in 1800 when Volta developed the first DC battery. Faraday used the DC battery to develop the first electric motor. It used brushes to transfer the battery voltage and current to the rotating disk rotor. This was in mid-1831. Thus was born the brush DC motor.

Feature Articles

Flexible Options with Flexible Shafts

You need to transmit a rotary motion where no straight line is possible. Or, you need to allow for some uncontrollable misalignment. How about transmission taking place between moving components? What if you need to control something in hazardous locations where you cannot directly handle the application, such as high-temperature environments, under hazardous conditions or in clean room applications? Functionally designed flexible shafts can meet all these challenges.