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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.
For Mark Findlay
of UK specialist driveline
consultancy Drive
System Design, reducing
gear noise to suit
the low noise levels in
an electric vehicle cabin
has meant throwing away the rule
book.
The chemical and physical properties of gear oils may change, depending - more or less - upon their formulation and the environmental conditions under which they are used. This is why - after three years of use in a wind turbine - a gear oil was examined to determine if indeed changes were evident and if the protection of the gears and rolling bearings still met the same requirements as would be expected of fresh oil. Our findings revealed that the existing gear oil - as well as its ability to protect the gears and rolling bearings - had degraded very little compared to fresh oil.
After a brief introduction to the importance of gear pumps in internal combustion engines, as well as in the most diverse hydraulic applications, a calculation method was applied that allows for sizing with considerably higher delivery rates. Upon identifying and analyzing a traditional pump, along with two construction solutions of asymmetric gear pumps, we then compared their related performances.
This paper outlines the design considerations that go into construction of a drive system in order to explain the importance of specific data, why it is required, and where design freedom is necessary. Apart from loads and speeds, interface dimensions and site specific conditions are also needed. Deciding up front which gear rating practice to select can affect the torque capacity of the drive train by ~15%.
When software goes bad, what do we call it? System failure? Human failure? A virus? A number of words will work. How about this? Glitch. It has that onomatopoeic quality that fairly screams, Downtime! And with good reason -- software-generated miscalculations can have very expensive -- if not perilous -- repercussions.