Download or read book Apparatus for Studying Ball Spinning Friction written by Steven T. Miller and published by . This book was released on 1965 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental apparatus was designed and constructed at the NASA Lewis Research Center to study one aspect of spinning friction based on interfacial slip over the entire ball-race contact area. The apparatus is capable of measuring spinning moments of less than 0. Ol inch-pound at maximum Hertz contact stresses to over 400 000 psi, speeds to 3500 rpm, and under varying contact configurations and conditions. From the torque measurement, a coefficient of spinning friction can be calculated. The apparatus comprises a drive assembly, a dead-weight load assembly, a spherical upper test specimen, a cylindrically grooved lower test specimen of varying conformity, a lower test specimen housing assembly incorporating a hydrostatic air-bearing assembly, and a torque-measuring system. In operation, the upper test specimen is loaded against the lower test specimen through the drive shaft assembly by the dead- weight load assembly. As the drive assembly is rotated, the upper test specimen rotates against the stationary lower test specimen actuating the torque-measuring system. Preliminary tests were conducted under varying Hertz stress to 136 000-psi maximum Hertz stress at a spinning speed of 950 rpm, with a 51 percent ball-groove conformity using a polyphenyl ether (5P4E), a highly purified naphthenic mineral oil, and a di-2-ethylhexyl sebacate (MIL-7808). It was found that the coefficient of spinning friction decreased with increasing maximum Hertz stress to an intermediate stress level and had a minimum value of 0. 122, 0. 089, and 0. 050, respectively, for the lubricants listed previously.
Download or read book NASA Technical Note written by and published by . This book was released on 1973 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Speed Effects on Ball Spinning Torque written by Dennis P. Townsend and published by . This book was released on 1969 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elastohydrodynamic analysis and experimental speed effects on ball spinning friction coefficients and torque.
Download or read book NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1966 with total page 1440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1965-07 with total page 1320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1973 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government wide Index to Federal Research Development Reports written by and published by . This book was released on 1965 with total page 1794 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lubrication Corrosion and Wear written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1966 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1980 with total page 1284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Selected Listing of NASA Scientific and Technical Reports for written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Division and published by . This book was released on 1965 with total page 1680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1971 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Generalized Rheological Model for Lubrication of a Ball Spinning in a Nonconforming Groove written by Charles W. Allen and published by . This book was released on 1973 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The elastohydrodynamic theory for predicting the spinning friction of a ball in a nonconforming groove was modified to incorporate a rheological model. The rheological model is based on the exponential pressure viscosity relation for low shear stresses, but at high shear rates and pressures, the relation is altered to one in which the shear stress is porportional to the normal stress. The model was fitted to experimental spinning torques for four different lubricants: a synthetic paraffinic lubricant, di-2-ethylhexyl sebacate, a super-refined naphthenic mineral oil, and a polyphenyl ether (5P4E). Good agreement between the model and experiment was found.
Download or read book Friction Losses in a Lubricated Thrust loaded Cageless Angular contact Bearing written by Dennis P. Townsend and published by . This book was released on 1973 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Conventional and Microasperity Elastohydrodynamic Lubrication of a Ball Spinning in a Nonconforming Groove written by Charles W. Allen and published by . This book was released on 1972 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analysis was developed for the microasperity elastohydrodynamic lubrication of a ball spinning in a nonconforming groove. This analysis was compared to the conventional elastohydrodynamic analysis of a ball spinning in a nonconforming groove. Rheological models for a di-2-ethylhexyl sebacate, a super-refined naphthenic mineral oil, and a polyphenyl ether (5P4E) were constructed from spinning torque data by using both analyses. The value of the lubricant pressure-viscosity coefficient that makes the data fit the analyses of the fluids differs somewhat from published data. For all three lubricants, an exponential composite model best described the lubricant rheology. Good agreement existed with the experimental and analytical values of torque for both the conventional and microasperity elastohydrodynamic analysis for a spinning ball in a nonconforming groove.
Download or read book Microasperity Model for Elastohydrodynamic Lubrication of a Spinning Ball on a Flat Surface written by Charles W. Allen and published by . This book was released on 1970 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A microasperity elastohydrodynamic (EHD) model was developed for a ball spinning without rolling on a f l a t surface. The theory was developed by using a sinusoidal surface model in conjunction with existing dry- contact deformation theory and point-contact elastohydrodynamic theory for the microasperities. The computed torques based on this model were compared with experimental torques using the NASA spinning torque apparatus. Fair agreement was obtained between theoretical and experimental results below 300 000 psi maximum Hertz stress. Based on the model presented herein microasperity EHD lubrication does not appear to be a primary force in maintaining separation between the opposing surfaces.
Download or read book A Study of the Coefficient of Friction in the American Compound Ball bearing and the Design of Suitable Apparatus for the Investigation written by W. DeWitt Vosbury and published by . This book was released on 1904 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
