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  • 1
    facet.materialart.
    Unknown
    Effect of two inner-ring oil-flow distribution schemes on the operating characteristics of a 35 millimeter bore ball bearing to 2.5 million DN (1985)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Parametric tests were conducted with a 35-mm-bore, split-inner-ring ball bearing with a double-inner-land-guided cage. Provisions were made for through-the-inner-ring lubrication. Test condictions were either a thrust load of 667 N (150 lb) or a combined load of 667 N (150 lb) thrust and 222 N (50 lb) radial, shaft speeds from 32000 to 72000 rpm, and an oil-inlet temperature of 394 K (250 deg F). Outer ring cooling was used in some tests. Tests were run with either 50 or 75 percent of the total oil flow distributed to the inner-ring raceway. Successful operation was experienced with both 50% and 75% flow patterns to 2.5 million DN. Cooling the outer ring had little effect on inner-ring temperature; however, the outer-ring temperature decreased as much as 7% at 2.5 million DN. Maximum recorded power loss was 3.1 kW (4.2 hp), and maximum cage slip was 8.7 percent. Both occurred at a shaft speed of 72000 rpm, a lubricant flow rate of 1900 cu/min (0.50 gal/min), a combined load, and no outer-ring cooling.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TP-2404 , E-2127 , NAS 1.60:2404
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Performance of jet- and inner-ring-lubricated 35 millimeter bore ball bearings operating to 2.5 million DN (1981)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Parametric tests were conducted with a 35 millimeter bore, angular contact ball bearing having a single outer land guided cage. Lubrication was achieved by flowing oil through axial grooves and radial holes machined in the inner ring of the bearing. Test conditions were a thrust load of 667 N (150 lb), shaft speeds from 48,000 to 72,000 rpm, and an oil inlet temperature of 394 K (250 F). Data from tests where the distribution of the total oil supplied to the inner ring was 50 percent for bearing lubrication and 50 percent for bearing inner ring cooling were compared with those where the distribution pattern was 25 percent lubrication and 75 percent cooling. Successful operation was experienced with both the 50-50 and 25-75 percent flow distribution patterns to 2.5 million DN. The 50-50 percent flow pattern provided the cooler bearing operation of the two inner ring lubricated bearings. The jet lubricated bearing had lower outer ring and higher inner ring temperatures than the inner ring lubricated bearings. Maximum power loss of 2.8 kW (3.7 hp) was experienced with the 25-75 percent flow distribution, and maximum percent cage slip of 7.0 occurred at 72,300 rpm with the 50-50 percent flow distribution.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TP-1808 , E-515
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Bearing fatigue investigation 3 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The operating characteristics of large diameter rolling-element bearings in the ultra high speed regimes expected in advanced turbine engines for high performance aircraft were investigated. A high temperature lubricant, DuPont Krytox 143 AC, was evaluated at bearing speeds to 3 million DN. Compared to the results of earlier, similar tests using a MIL-L-23699 (Type II) lubricant, bearings lubricated with the high density Krytox fluid showed significantly higher power requirements. Additionally, short bearing lives were observed when this fluid was used with AISI M50 bearings in an air atmosphere. The primary mode of failure was corrosion initiated surface distress (fatigue) on the raceways. The potential of a case-carburized bearing to sustain a combination of high-tangential and hertzian stresses without experiencing race fracture was also investigated. Limited full scale bearing tests of a 120 mm bore ball bearing at a speed of 25,000 rpm (3 million DN) indicated that a carburized material could sustain spalling fatigue without subsequent propagation to fracture. Planned life tests of the carburized material had to be aborted, however, because of apparent processing-induced material defects.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-CR-168029 , NAS 1.26:168029 , GE-R82AEB304
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Effect of cage design on characteristics of high-speed-jet-lubricated 35-millimeter-bore ball bearing (1980)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Parametric tests were conducted with a 35 mm bore angular contact ball bearing with a double outer land guided cage. Provisions were made for jet lubrication and outer-ring cooling of the bearing. Test conditions included a combined thrust and radial load at nominal shaft speeds of 48,000 rpm, and an oil-in temperature of 394 K (250 F). Successful operation of the test bearing was accomplished up to 2.5 million DN. Test results were compared with those obtained with similar bearing having a single outer land guided cage. Higher temperatures were generated with the double outer land guided cage bearing, and bearing power loss and cage slip were greater. Cooling the outer ring resulted in a decrease in overall bearing operating temperature.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TP-1732 , E-289
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TN-D-8404 , E-8825
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Design, fabrication, and operation of a test rig for high-speed tapered-roller bearings (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A tapered-roller bearing test machine was designed, fabricated and successfully operated at speeds to 20,000 rpm. Infinitely variable radial loads to 26,690 N (6,000 lbs.) and thrust loads to 53,380 N (12,000 lbs.) can be applied to test bearings. The machine instrumentation proved to have the accuracy and reliability required for parametric bearing performance testing and has the capability of monitoring all programmed test parameters at continuous operation during life testing. This system automatically shuts down a test if any important test parameter deviates from the programmed conditions, or if a bearing failure occurs. A lubrication system was developed as an integral part of the machine, capable of lubricating test bearings by external jets and by means of passages feeding through the spindle and bearing rings into the critical internal bearing surfaces. In addition, provisions were made for controlled oil cooling of inner and outer rings to effect the type of bearing thermal management that is required when testing at high speeds.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134595 , ITI-P-1248
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Experimental ball bearing dynamics study (1973)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A photographic method was employed to record the kinematic performance of rolling elements in turbo machinery ball bearings. The 110 mm split inner ring test bearings had nominal contact angles of 26 deg and 34 deg. High speed films were taken at inner ring speeds of 4,000, 8,000 and 12,000 rpm and at thrust loads of 4,448 N and 22,240 N (1,000 and 5,000 lbs). The films were measured and this data reduced to obtain separator speed, ball speed and ball spin axis orientation.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA-CR-134528 , ITI-P-1246
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Performance of computer-optimized tapered-roller bearings to 2.4 million DN (1980)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The performance of 120.65 mm bore high speed design tapered roller bearings was investigated at shaft speeds to 20,000 rpm under combined thrust and radial load. The test bearing design was computer optimized for high speed operation. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rates, and lubricant inlet temperature. The roller bearing operated successfully at shaft speeds up to 20,000 rpm under heavy thrust and radial loads. Cup cooling was effective in decreasing the high cup temperatures to levels equal to the cone temperature.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-81414 , E-332 , Intern. Lubrication Conf.; Aug 18, 1980 - Aug 21, 1980; San Francisco
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Lubrication of high-speed, large bore tapered-roller bearings (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The performance of 120.65-mm- (4.75-in.-) bore tapered-roller bearings was investigated at shaft speeds up to 15,000 rpm (18,000 DN). Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied either by jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA-TM-X-73673 , E-8825 , Joint Lubrication Conf.; Oct 03, 1977 - Oct 05, 1977; Kansas City
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Lubrication of 35-millimeter-bore ball bearings of several designs at speeds to 2.5 million DN (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Parametric tests were conducted with 35mm bore, angular contact ball bearings with either a single or double-outer-land-guided cage. The bearings were either lubricated by oil jets or employed inner ring lubrication. Outer ring cooling was added in selected tests. Test conditions were a radial load of 222 N (50 lb) and/or a thrust load of 667 N (150 lb), shaft speeds to 72,000 rpm, and an oil inlet temperature of 394 K (250 F). Lubricant flow to the bearing ranged rom 300 to 1900 cc/min (0.08 to 0.50 gal/min). All bearings were successfully run at speeds to 2.5 million DN. Increasing the lubricant flow decreased bearing ring temperatures but increased bearing power loss. The power loss and race temperatures of a jet lubricated bearing with double-outer-land-guided cage were always higher than those of the single-land-guided-design at similar test conditions. The lowest bearing operating temperatures were achieved when inner ring lubrication and outer ring cooling were combined. Cage slip of a double-outer-land-guided cage was approximately twice that of a single-outer-land-guided cage.
    Keywords: MECHANICAL ENGINEERING
    Type: AGARD Probl. in Bearings and Lubrication; 15 p
    Format: text
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    NASA TECHNICAL REPORTS
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