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  • 1
    facet.materialart.
    Unknown
    Method of producing improved bearing components by elimination of control of fiber orientation, including magnetic analysis quarterly report, 16 mar. - 15 jun. 1962 (1962)
    In:  CASI
    Details
    Publication Date: 2019-05-25
    Keywords: unknown
    Type: QR-12
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Unknown
    Spin axis bearings Summary report (1966)
    In:  CASI
    Details
    Publication Date: 2019-05-30
    Description: Dynamic testing and failure analyses of spin axis bearings in gyro assemblies for spacecraft guidance system applications
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-77365
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Comparison of experimental and predicted performance of 150-millimeter-bore solid and drilled ball bearings to 3 million DN (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Seven 150-millimeter-bore ball bearings were run under 8900-newton (2000-lbf) thrust load at speeds from 6670 to 20,000 rpm (1 million to 3 million DN). Four of the bearings had conventional solid balls, and three bearings had drilled (cylindrically hollow) balls with 50-percent mass reduction. The bearings were under-race cooled and slot lubricated with a type 2 ester oil at flow rates from 4.35 x 0.001 to 5.94 x 0.001 cubic meter/min (1.15 to 1.57 gal/min). Friction torque and temperature were measured on all bearings. While there was considerable spread in the temperature data, the drilled ball bearings tended to run slightly cooler than the solid ball bearings at higher speeds. No significant difference in torque was noted, however, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800-newton (4000-lbf) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball, and cracks appeared in other balls as a result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TN-D-7737 , E-7722
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Effect of ball geometry on endurance limit in bending of drilled balls (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Four designs of drilled (cylindrically hollow) balls were tested for resistance to bending fatigue. Bending fatigue has been demonstrated to be a limiting factor in previous evaluations of the drilled ball concept. A web reinforced drilled ball was most successful in resisting bending fatigue. Another design of through drilled design, involving a heavier wall than the standard reference ball, also showed significant improvement in resistance to bending fatigue.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-134930
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Experimental evaluation of 150-millimeter bore ball bearing to 3 million DN using either solid or drilled balls (1973)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Seven 150-mm bore ball bearings were run under 8900 Newton (2000 lb) thrust load at speeds from 6670 to 20,000 rpm (1 to 3 million DN). Four of the bearings had conventional solid balls and three bearing had drilled (cylindrically hollow) balls with 50 percent mass reduction. The bearings were under-race cooled and slot-lubricated with Type 2 ester oil at flow rates from 4.35 to 5.80 liters per minute (1.15 to 1.57 gal min). Friction torque and temperatures were measured on all bearings. No significant difference in torque was noted, between the solid and drilled ball bearings. One bearing of each type was rerun at 17,800 Newtons (4000 lb) thrust load. The solid ball bearings performed satisfactorily at 3 million DN. However, at about 2 million DN the drilled ball bearing experienced a broken ball and cracks appeared in two other balls as the result of flexure fatigue. Metallurgical examination of the cracked balls indicated a brittle structure in the bore of the drilled balls.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-TM-X-68265 , E7566 , Joint Lubrication Conf.,; Oct 16, 1973 - Oct 18, 1973; Atlanta, GA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Unknown
    Dynamic load capacities of graphite fiber: Polyimide composites in oscillating plain bearings to 340 C (650 F) (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Load capacities were determined for plain spherical bearings with self-lubricating spherical elements of graphite-fiber-reinforced-polyimide, and for plain cylindrical bearings with thin-wall liners of the composite in the bearing bores. Composites consisted of a 1-to-1 weight ratio of graphite fibers and polyimide. Oscillation was at an amplitude of + or - 15 deg at a frequency of 1 hertz. Bearings with composite ball material had a load capacity of approximately 69 MN/sq m (10 000 psi) at room temperature 25 MN/sq m (3600 psi) at 340 C (650 F). Bearings with thin-wall composite liners had much higher load capacities of 280 MN/sq m (40 000 psi) at room temperature amd 240 MN/sq m (35 000 psi) at 320 C (600 F). Friction coefficients were in the range of 0.12 to 0.19. The addition of 10 wt.% graphite fluoride solid lubricant to the composition of the thin-wall liners reduced friction coefficients into the range of 0.10 to 0.12.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TN-D-7880 , E-8118
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Experimental evaluation of 150-millimeter bore ball bearings to 3-million DN using either solid or drilled balls (1973)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: ASME PAPER 73-LUB-19 , Joint Lubrication Conference; Oct 15, 1973 - Oct 18, 1973; Atlanta, GA; US
    Format: text
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    NASA TECHNICAL REPORTS
  • 8
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    Unknown
    Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines (1992)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.
    Keywords: METALLIC MATERIALS
    Type: NASA-CR-193731 , NAS 1.26:193731 , EER-1041
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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