Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

EDITORS’ NOTE: “The Applications of Bevel Gears” is the excerpted third chapter of Dr. Hermann Stadtfeld’s latest book — Gleason Bevel Gear Technology (The Gleason Works, Rochester, New York, USA; All rights reserved. 2014; ISBN 978-0-615-96492-8.), which appears here unabridged through the kind graces of Dr. Stadtfeld and Gleason Corp. Future installments will appear exclusively in Power Transmission Engineering and Gear Technology magazine over the next 12 to 18 months.

PERSONNEL CHANGES AND EXPANSION HIGHLIGHT CICERO, ILLINOIS GEAR MANUFACTURER

A reader asks: I've determined that a stainless steel bearing is the best option for my application. I'm being asked to specify the grade of stainless steel in my product design. I'm not sure which grade to select and specify. Can you help?

We are pleased to present our first annual Engineering Showcase, a celebration of some of the leading products and companies in mechanical power transmission. In the pages that follow, you’ll find examples of engineering excellence and technological know-how in the field of gears, drives, couplings, machine parts and other mechanical components.

The development of a new, gas-carburized gear steel, necessitated by a customer-driven specification, has not only increased the power density in an existing gearbox design, but has done so without requiring any significant change to production processes or heat treatment equipment.

This paper is part 2 of 2 in a series that summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.

Seal design engineers and end users are continually seeking improved sealing systems and materials. This paper describes the potential of a new thermoplastic polyurethane (TPU) material to deliver improvements in pressure, speed and temperature capability, which are presented as comparisons to proven industry standard materials. Performance is demonstrated by virtue of test bench results of seals made from MDI-, PPDI- and NDI-based materials.

Managing Editor Randy Stott recounts a recent visit to Siemens manufacturing and assembly facilities in Elgin, IL.

A new solution has been developed around the use of microprocessor-controlled prostheses. Just like natural limbs, these can react automatically, adapting to the current situation.