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Load capacity and losses in the infinite slider bearing with transversely forcedcooled lubricant film
300
SYSTEMATIC ABSTRACTS OF CITRRENT I>I’lERAT~-RI3
A micro-fibrous form of colloidal alumina (boehmite) is shown to act as a superior nonencapsulating binder for molybdenum disulphide in the formation of ductile, water resistant dry lubricant films which exhibit lower coefficients of friction than have been reported for molybdenum disulphide or graphite films bonded with other materials. The films have good load-carrying ability and durability. Opt~mun~ performance is obtained when the correct ratio of boehmitc to MoSa is used, the film is 0.2-0.5 mil thick, the substrate is hard and highly polished and the film is applied in an alkaline dispersion and dehydrated by baking a.t 550’F.
MO& Second Thoughts. E. R. Braithwaite, Ilzd. Lzabricatiota, ZI (8) (1969) qr-zq7; 3 figs., 3 tables, 22 refs. The physical and surface chemical factors which may influence the lubricating action of molvbdenum disulphide are discussed; the importance of part& size and shape are emphasised. Current thoughts on the lubrication mechanism are examined together with various environmental factors which can affect its industrial use. Recent development work particularly with respect to MOSS greases is reported; proper formulation is essential if the full benefits of MO% as a lubricant additive are to be utilised effectively, The economics of MoS? lubricants are dealt11 with.
A Test of Molybdenumdisulphide Lubricants
in Radiation and Vacuum Environments. J. H. Lewis and R. H. McDaniel, JOLT, 91, Ser. F, (3) (1969) 390-396; 6 figs., 8 tables, IO refs. Tests were carried out on two Mo$base solid-film Iubricants potentially suitable for use under severe environmental conditions. One lubricant contained gold and sodium silicate and the other bismuth and aluminium phosphate. The gold containing lubricant applied to test specimens of 440C steel and Rem! 41 was irradiated and tested under sliding conditions at temperatures up to IZOO’F. Both lubricants were tested in vacuum and in air on ball bearings run at 6000 r.p.m. in servomotors. No significant radiation effects were detected with the MO&/ gold lubricant on 440C steel but the test data indicated a possible radiation effect at hoo”F but not at other temperatures on Rene 41. In two vacuum tests on bearings the MoSz/gold lubricant gave a mean life of I 10 h; the MO%/ Bi film gave a mean life of 96 h in the first test and 853 h in the second test. Careful detailed testing is required to further explore lubricant potential. Wear, rq (1969) 296-307
Why, What and How: Engine Varnish. 3%.Dimitroff, J. V. Moffitt and R. D. Quillian, ./QI/T, gr, Sev. F, (3) (1969) 406-4rG; 15 figs., 13 tables, 6 refs Engine tests were conducted to investigate varnish formation and to establish the interrelationships between fuels, lubricants, additives and engine operating with respect to their effect on the phenomena. The x-arnish precursors were primarily fuel aromatic compounds and varnishing characteristics are more dependent upon the individual components -than the -total aromatics present. Finished lubricants act as varnish inhibitors. Of the engine variables only compression ratio and jacket temperature were found to bc important. Chemical analysis showed that cnginevarnish is mostly alkaline and contains condensed 11~7drocar~?ons,hydrous-containing organic compounds, ketones and nitro compounds. Lead salts may be present but arc not a prerequisite to varnish formation. Data arc provided which show that piston varnish formation is a chemical process which occurs on the rubbing surface as the blow-by travels from the combustion chamber to the sump.
4. MACHINE
PARTS
4.1. Bpurings Load Capacity and Losses in the Infinite Slider Bearing with Transversely Forced* cooled Lubricant Film. E. L. Kuhn, ASLE Trans., 12 (2) (1969) 135-139; 4 figs., 5 refs. An analysis ‘is made of the infinite slider bearing with transverse cooling of the oil film. The results were obtained by numerically solving simultaneously the equations of motion and energy in which the lubricant viscosity depends on temperature with an adiabatic condition at the runner and a parabolic inlet temperature distribution, the difference between the runner temperature and pad surface temperature for the fullycooled film depends on pad temperature, slide speed and fluid prope&es. The slider losses and load capacity can be greater or lesser than those predicted by classical solutions based on viscosity at the pad surface temperature althoughthepivotlocationremainsunchanged from that predicted. Contact Traction and Creep of Lubricated, Cylindrical Rolling Elements at Very High Surface Speeds. L. 0. Hewko, ASLE Trcclas., 12 (z) (1969) 151-161; 20 figs., g refs. The paper discusses results obtained on a
SYSTEMATIC ABSTRACTS OF CITRRENT I>I’lERAT~-RI3
A micro-fibrous form of colloidal alumina (boehmite) is shown to act as a superior nonencapsulating binder for molybdenum disulphide in the formation of ductile, water resistant dry lubricant films which exhibit lower coefficients of friction than have been reported for molybdenum disulphide or graphite films bonded with other materials. The films have good load-carrying ability and durability. Opt~mun~ performance is obtained when the correct ratio of boehmitc to MoSa is used, the film is 0.2-0.5 mil thick, the substrate is hard and highly polished and the film is applied in an alkaline dispersion and dehydrated by baking a.t 550’F.
MO& Second Thoughts. E. R. Braithwaite, Ilzd. Lzabricatiota, ZI (8) (1969) qr-zq7; 3 figs., 3 tables, 22 refs. The physical and surface chemical factors which may influence the lubricating action of molvbdenum disulphide are discussed; the importance of part& size and shape are emphasised. Current thoughts on the lubrication mechanism are examined together with various environmental factors which can affect its industrial use. Recent development work particularly with respect to MOSS greases is reported; proper formulation is essential if the full benefits of MO% as a lubricant additive are to be utilised effectively, The economics of MoS? lubricants are dealt11 with.
A Test of Molybdenumdisulphide Lubricants
in Radiation and Vacuum Environments. J. H. Lewis and R. H. McDaniel, JOLT, 91, Ser. F, (3) (1969) 390-396; 6 figs., 8 tables, IO refs. Tests were carried out on two Mo$base solid-film Iubricants potentially suitable for use under severe environmental conditions. One lubricant contained gold and sodium silicate and the other bismuth and aluminium phosphate. The gold containing lubricant applied to test specimens of 440C steel and Rem! 41 was irradiated and tested under sliding conditions at temperatures up to IZOO’F. Both lubricants were tested in vacuum and in air on ball bearings run at 6000 r.p.m. in servomotors. No significant radiation effects were detected with the MO&/ gold lubricant on 440C steel but the test data indicated a possible radiation effect at hoo”F but not at other temperatures on Rene 41. In two vacuum tests on bearings the MoSz/gold lubricant gave a mean life of I 10 h; the MO%/ Bi film gave a mean life of 96 h in the first test and 853 h in the second test. Careful detailed testing is required to further explore lubricant potential. Wear, rq (1969) 296-307
Why, What and How: Engine Varnish. 3%.Dimitroff, J. V. Moffitt and R. D. Quillian, ./QI/T, gr, Sev. F, (3) (1969) 406-4rG; 15 figs., 13 tables, 6 refs Engine tests were conducted to investigate varnish formation and to establish the interrelationships between fuels, lubricants, additives and engine operating with respect to their effect on the phenomena. The x-arnish precursors were primarily fuel aromatic compounds and varnishing characteristics are more dependent upon the individual components -than the -total aromatics present. Finished lubricants act as varnish inhibitors. Of the engine variables only compression ratio and jacket temperature were found to bc important. Chemical analysis showed that cnginevarnish is mostly alkaline and contains condensed 11~7drocar~?ons,hydrous-containing organic compounds, ketones and nitro compounds. Lead salts may be present but arc not a prerequisite to varnish formation. Data arc provided which show that piston varnish formation is a chemical process which occurs on the rubbing surface as the blow-by travels from the combustion chamber to the sump.
4. MACHINE
PARTS
4.1. Bpurings Load Capacity and Losses in the Infinite Slider Bearing with Transversely Forced* cooled Lubricant Film. E. L. Kuhn, ASLE Trans., 12 (2) (1969) 135-139; 4 figs., 5 refs. An analysis ‘is made of the infinite slider bearing with transverse cooling of the oil film. The results were obtained by numerically solving simultaneously the equations of motion and energy in which the lubricant viscosity depends on temperature with an adiabatic condition at the runner and a parabolic inlet temperature distribution, the difference between the runner temperature and pad surface temperature for the fullycooled film depends on pad temperature, slide speed and fluid prope&es. The slider losses and load capacity can be greater or lesser than those predicted by classical solutions based on viscosity at the pad surface temperature althoughthepivotlocationremainsunchanged from that predicted. Contact Traction and Creep of Lubricated, Cylindrical Rolling Elements at Very High Surface Speeds. L. 0. Hewko, ASLE Trcclas., 12 (z) (1969) 151-161; 20 figs., g refs. The paper discusses results obtained on a