It is my turn to write the Foreword section of this newsletter. The feedback from some of the readers indicates that the practice of alternating authorship between yours truly and one of the members of the Board of Trustees has been well received.
In spite of an uncertain economy in 2012, a steady stream of gear related research and testing projects flowed through GRI. Repeat projects from industrial sponsors, which are also a measure of their satisfaction with our output, was also a hallmark of last year. The Aerospace Bloc benefited from a sponsor rejoining the group after a hiatus of a few years. This steady flow of research funds also allowed us to allocate and expend resources to support succession transitions, as some of us start to approach our “golden years”. The Board also authorized funds to hire an additional undergraduate student to work at GRI.
The past year also saw changes in the constitution of the Board of Trustees. Joining the Board, as an ASME representative, was Professor Teik Lim of the University of Cincinnati, replacing Al Swiglo of Northern Illinois University. Al had served as a Board member and the Treasurer of the Institute for many years. We also elected our first female Board member as Ms. Colleen Tomasello of Latrobe Steel replaced Mr. Terrell Hansen of the Boeing Company. Terrell served as a Board member for over a decade and his guidance and support of the Institute will always be cherished. The membership of the Institute also voted to expand the Board of Trustees by one more member, bringing the total from 9 to 10. In an increasingly busy world obtaining a quorum of 6 members at any Board meeting will become a little easier. Immediately following that Mr. Tom Doubts from GE Aviation was elected as the tenth Board member.
The New Year promises to be a busy one, as we try to full fill our research obligations that we took on in 2012. Hopefully, all our readers had a very satisfactory 2012 and look forward to an exciting 2013.
Suren B. Rao
Frictional losses in gear boxes are of significant interest to gear box designers as these transform into heat. In a world where fuel efficiency is uppermost in everybody’s mind, these losses directly result is a reduction in the fuel efficiency of the vehicle involved. Further, in many instances, this heat has to be absorbed and dissipated so that lubricant properties and gear box performance are not significantly compromised. This effort, sponsored by REM Surface Engineering, is to measure and document the comparative friction losses in a gear mesh due to gear tooth surface condition and lubricant. Three distinct surface conditions are considered. They are Ground, Isotropic Superfinished (ISF®) and coated (Timken ES322). Two lubricants, MIL-23699 and Mobil SHC 626 lubricants are also evaluated.
The experimental effort is conducted on a high speed, power re-circulating (PC), gear test rig, which had been specially instrumented with a precision torque transducer to measure input torque to the 4-square loop. The figure below shows the torque transducer, consisting of a rotor and a stator, mounted between the input spindle and the reversing gear box of the PC test rig, with the test gear box cut away and further to the right of the figure. The torque required to drive the loop is measured under various speeds and tooth loads within the loop, with gears of different surface conditions and with different lubricants. Using ground gears operating in MIL-23699 as a base line, the increase or decrease in the input torque, as measured by the precision torque transducer, is a measure of the change in friction losses at the gear mesh due to surface condition and or lubricant. Further, the surface characteristics of the tooth flanks of the ground, superfinished and coated gears are also presented and discussed.
Education and Training
In order to assist the gear industry augment its aging work force, the Gear Research Institute has proposed two initiatives to train more gear knowledgeable engineers at the undergraduate and graduate levels. This involves incorporating engineering undergraduate students at the junior/senior level and graduate students in the Institute’s research efforts while being paid by a grant from the sponsoring industrial entity. Summer internships at the sponsor’s facility are also a part of the deal so that the student and the sponsor have an opportunity to assess each other with future employment in mind.
The Gear Research Institute is a non profit corporation. It has contracted with the Applied Research Laboratory of The Pennsylvania State University to conduct its activities, as a sponsor within the Drivetrain Technology Center. The Gear Research Institute is equipped with extensive research capabilities. These include rolling contact fatigue (RCF) testers for low- and high-temperature roller testing, power circulating (PC) gear testers for parallel axis gears with a 4-inch center distance (testers can be modified to accommodate other center distances), single tooth fatigue (STF) testers for spur and helical gears, gear tooth impact tester, and worm gear testers with 1.75 and 4-inch center distances. Extensive metallurgical characterization facilities are also available at Penn State in support of the Gear Research Institute. For further details on our testing capabilities please go to the Drivetrain Technology Center website or call Dr. Suren Rao, Managing Director, at (814) 865-3537.