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  • 1
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    Dynamic Testing of a High-Specific-Torque Concentric Magnetic Gear (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This presentation presents measurements of the efficiency of NASA's 2nd magnetic gear prototype. A detailed discussion of the test rig used to make these measurements was presented, including a thorough uncertainty analysis. The reported uncertainties are 95% confidence intervals that include the effects of temperature and parasitic loads. The prototype's response was measured at output speeds between 124 rpm and 744 rpm for a controlled output torque of 10 Nm (8% of the prototype's maximum torque). After correcting for tare losses, the prototype's efficiency was found to decrease from 90.0% to 83.0% as speed increased. If the efficiency is extrapolated to a typical operating condition (85% of maximum torque) using the good assumption that energy loss is approximately independent of the transmitted torque,the expected efficiency would be 99.0% to 98.4%, which exceeds the state of the art for these speeds.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN68758 , Vertical Flight Society''s Annual Forum & Technology Display; May 13, 2019 - May 16, 2019; Philadelphia, PA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
  • 2
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    Design Space Exploration of Pericyclic Transmission with Counterbalance and Bearing Load Analysis (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN54774 , AHS International Annual Forum & Technology Display; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
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    Design Space Exploration of Pericyclic Transmission with Counterbalance and Bearing Load Analysis (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN56075 , AHS International Annual Forum & Technology Display; May 14, 2018 - May 17, 2018; Phoenix, AZ; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
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    Design Space Exploration of Pericyclic Transmission (2018)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: The pericyclic transmission provides the opportunity to vastly impact transmission design in rotorcraft due to its ability to provide exceedingly high reduction ratios in a single stage that would normally require multiple gear stages to produce. This could lead to lighter transmissions with fewer components, increased range, reliability, efficiency, speed and decreased cost to maintain. While many previous studies have focused upon the gearing within the pericyclic transmission, this work focused on what influences pericyclic geometry, and how changes in geometry impacts bearing loads. Specifically the loading of bearings that must deliver power from the input shaft to the nutating and rotating gears of the system were of primary concern. A comprehensive look at dynamic loads generated by nutating bodies was performed. Methods to address these dynamic loads via application of counterbalances and deviation from conventional pericyclic transmission designs were utilized to negate the dynamic moment of concern. Finally a static solver was used to determine the bearing loads with updated component geometries and mass moment of inertias that included the required counterbalances.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN59816 , SLaMS ECF; Aug 21, 2018 - Aug 24, 2018; Greenbelt, MD; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
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    Magnetic Gears and Their Structural Limitations (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-30
    Description: Magnetic gears present significant structural design challenges, because metallic/electrically conductive structures are highly undesirable as they would lead to significant efficiency reductions. Additionally, most non-electrically conductive structural materials have low thermal conductivity, which makes cooling the gear difficult. These limitations are of particular significant in magnetic gear's modulator structures. NASA Glenn has shown that pole pieces on the order of 1 to 2 mm thick optimize magnetic gears specific torque. These thin pole pieces however see very large magnetic forces and modulator structural limitations prevent the use of magnetically optimum pole pieces. The best solution to this issue to date has been the use of carbon fiber retaining rings on the external surface of the modulator, however this solution increases ring modulator airgap, resulting in a torque reduction from the optimum design. The pole pieces are also the largest sources of losses in magnetic gears. Because the modulator is nestled between the ring and sun gear extraction of this heat is a difficult problem and the modulator structure has to be designed to dissipate this heat load. In the presentation I will present the design of NASA Glenn's 4th magnetic gear's modulator in detail that uses a combination of 3D fiber reinforced nylon, IM7 carbon fiber, and pitch base cn80 fiber to close both structurally and thermally.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN72797 , Slams 2019; Sep 09, 2019 - Sep 13, 2019; Palmdale, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
  • 6
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    High Speed Testing of a High Efficiency Concentric Magnetic Gear (2019)
    In:  CASI
    Details
    Publication Date: 2019-11-09
    Description: This presentation presents measurements of the efficiency of NASA's 2nd magnetic gear prototype. A detailed discussion of the test rig used to make these measurements was presented, including a thorough uncertainty analysis. The reported uncertainties are 95% confidence intervals that include the effects of temperature and parasitic loads. The prototype's response was measured at output speeds between 124 rpm and 744 rpm for a controlled output torque of 10 Nm (8% of the prototype's maximum torque). After correcting for tare losses, the prototype's efficiency was found to decrease from 90.0% to 83.0% as speed increased. If the efficiency is extrapolated to a typical operating condition (85% of maximum torque) using the good assumption that energy loss is approximately independent of the transmitted torque,the expected efficiency would be 99.0% to 98.4%, which exceeds the state of the art for these speeds.
    Keywords: Mechanical Engineering
    Type: GRC-E-DAA-TN73438 , Propulsion and Power Technical Meeting; Oct 29, 2019 - Oct 30, 2019; Hampton, VA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
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