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When comparing bearing suppliers,
engineers are often left with few options
other than to compare dynamic
load ratings and corresponding life
calculations. Of course, we can look at
steel and manufacturing quality; but
if we are comparing sources of similar
quality, those items may not provide
a large contrast. It often surprises
people to learn that bearing capacities
are calculated values, not tested values.
Lately, however, a trend is emerging
for bearing suppliers to increase their
ratings for higher performance bearings
that have premium features such
as higher quality steel and specilaized
heat treatment. Bearing companies are
under intense competitive pressure to
make every feature add to the dynamic
capacity of their bearings because it is very well understood that an increase in capacity adds to the bottom line.
The changing landscape of hydraulic drives is leading many fluid power specialists to quickly adapt to using variable speed pump drives. Optimum utilization of these drives requires, in many cases, additional system design considerations.
Some of us are old enough to
have had say, great-grandparents,
for example, who
when the occasion arose
would casually refer to cars
as “machines.” It sounded funny
and arcane, and we would snicker under
our breath. But of course the laugh
was on us; back in the day — 1910s
through the 1930s — automobiles were
commonly referred to as machines.
The motors might be small, but the big-brain technology driving these electrical wonders was on full display at the 2014 Small Motor &
Motion Association Fall Technical Conference, convened November 4-6 in St. Louis, MO. SMMA, the manufacturing trade association (120 members
strong) that tends to the best interests of the electric motor
and motion control industries — including manufacturers, suppliers, users, consultants and universities — played gracious host to a wide array of presenters from an equally diverse range of sources — from academia to the federal government. Like gears, motors are most everywhere, as evidenced by SMMA’s membership (consumer-, public interest-, national defense- and commercial-oriented) demographic
which includes: appliance; transportation; medical equipment; office automation and computers; aerospace; and industrial automation. The association’s mission: To “serve as the principal voice of the electric motors and drives industry” and to provide a forum to “develop, collect and disseminate technical and management knowledge.”
A wide variety of companies displayed mechanical power transmission and motion control technologies at Pack Expo, held in November in Chicago. The event, which is the largest packaging and processing trade show in North America, attracted more than 48,000 attendees, according to show owner and producer PMMI. The four-day event included 2,352 exhibiting companies, an increase of more than 19 percent from the previous show in 2012.
With two armed conflicts underway impacting economic performance in Eastern Europe and the Middle East, we
continue our investment stance of “Buy on the Sound of Cannons — Selectively” — but readers of Power Transmission
Engineering should not be sanguine.
Geopolitics is beginning to exert significant pressure on several end markets: I specifically refer to oil price. West Texas Intermediate or WTI has dropped from its $95-105 trading
range in late spring to about $75 — about a (25%) drop despite
wo ongoing conflicts because of excess supply.
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.
Four types of gear devices with great transmission ratios (simply called great ratio gears or GRGs) are
discussed in this paper. They are strain wave gearing devices (SWGs), trochoidal gear reducers (TGRs),
hypocyclic gear reducers (HGRs) and James Ferguson-type planetary drives (JFDs). The structures, advantages and basic performances of these four devices are compared. The latest design and strength analysis methods are also introduced. To conclude, the future tendencies of GRGs are predicted.