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One of the key challenges in the mining
industry today is maintaining throughput
in the face of ore grade quality that
has declined by 40 percent in the last
decade.
Machine and equipment manufacturers
today are feeling more pressure
than ever to reduce costs without sacrificing
machine performance — a balancing
act difficult to achieve. OEMs often overlook a simple solution that can have a positive, long-term impact
on profitability for themselves and
their customers, i.e. — the elimination of bearing lubricant.
Spiroid and worm gears have superior advantages for hightorque and miniaturization applications. And for this reason they are particularly preferred in aerospace, robotic and medical applications. They are typically manufactured by hobbing technology, a process with a typical overall lead time of 4 to 14 weeks.
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.
The use of motor current signature analysis (MCSA) for motor fault detection — such as
a broken rotor bar — is now well established. However, detection of mechanical faults
related to the driven system remains a more challenging task. Recently there has been a growing interest for detection of gear faults by MCSA. Advantages and drawbacks of these
MCSA-type techniques are presented and discussed on a few industrial cases.
Bill Walton – a 7 foot tall anomaly
from the annals of basketball history
who wears tie-dye shirts, listens to the
Grateful Dead and, according to his
own outlandish proclamations, hasn’t
taken an indoor shower in 35 years – is
well-known for looking at average accomplishmentsand being overcome
with extreme fits of emotion.
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.