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The lubrication of bearings at high temperatures
SYSTEMATIC ABSTRACTS give better bearing wear performance than their comparable mineral oil counterparts despite the fact that they have a lower apparent viscosity at high rates of shear. In addition, it appears that temporary viscosity loss is not the sole cause of the reduced engine friction of polymer-thickened oils.
2s
Extreme Pressure Lubricants for Marine Gears. A. D. Newman. Pvoc. Inst. Mech. Engvs. (London), r74 (5) (1960) q-246. An extreme pressure oil may be used where the design per se requires a higher loadcarrying capacity than that provided by a normal oil and where its use will afford insurance against trouble.
4. MACHINE PARTS
Orthogonally Displaced Beatings. I. Donald F. Wilcock. ASLE Paper No. 60 LC-7, Oct. 1960, 1-7; 13 figs., I table, 9 refj. Journal bearings with cross sections consisting of circular arcs with centers displaced from the geometric bearing center along the midradius of the arc or lobe have been in use for many years. Examples are the “elliptical” bearing and the “three-lobe” bearing, the advantage sought being increased stabilitv under light loads without the reduced oil flow accompanying a reduced clearance ratio. The analysis was ‘carried out for a bearing having in cross section two arcs each subtending an angle of 15o’, an L/D ratio of &,
and with the arc centres each displaced from the geometric center by half the radial clearance. The Lubrication of Beatings at High Temperatures. E. G. Ellis. Sci. Lubrication (Londo,z), ~2 (1960) 16 + 6 pages. Much work on high temperature conditions and bearing ma.terial/lubricant combinations must be carried out before all the problems are solved. Promising combinations with certain limitations are: self-lubricating bearings, gas lubricated bearings, organic liquid “once-through” systems, solid lubricants and controlled atmospheres.
5. WEAR AND WEAR RESISTANCE 5.1. Conventional
Engineering
Mechanical Wear. G. W. Rowe. Appl. Mechanics Reviews, 13 (1960) 787-790; 24 refs. Principles of wear testing; selected experimental investigations; theories and laws of wear; corrosive wear and the influence of temperature; wear prevention or reduction. Hardening of Metals during Friction and the Strength of Steel during RepeatedlyXhanging Loadings (in Russian). D. A. Draigor and G. I. Valchuk. Sbornik Trudov Inst. Stroit. Mekh. Akad. Nauk S.S.R. 22 (1956) 93-99; Ref. Zlzur. Mekh., no. 2 (1959) Rev. 2077; Source: Appl. Mechanics Reviews 13 (9) (1960) TOI. An investigation is made on the influence of the process of hardening of the rubbing surfaces on the fatigue resistance and durability. A durability coefficient was determined. Polishing of the surface of the specimen with the elimination of centres of hardening resulted in the re-establishment of durability. Durability was not re-established by polishing when there was prolonged friction action on steels of a metastable structure. Abrasion Tests on Carpets Using Different Abtadants. Dorothy G. Clegg and S. L. Anderson. J. Textile Inst., Trans., 51 (9) (1960) T 385T 39r ; 4 figs., 5 tables, IO refs.
The effect of several abradants on nylon, viscose rayon, nylon/viscose blends and allwool carpets of the same construction was investigated on a Schiefer machine. While all abradants ranked the nylon/viscose carpets in the same order, the ranking of the all-wool carpet depended on the abradant used. Severe abradants, such as emery, show the least discrimination between different fibres. From a comparison with service trials by Sturlcy and Westhead (J. Textile Inst., 49 (1958) P 538) it follows that 509/o viscosenylon carpets have the highest wear resistance both in laboratory and service trials. The other compositions from 100% viscose with increasing quantities of nylon are given in the correct rank order with a BCA-type abradant. Wool carpets are classed by the machine still lower than in actual service. 5.2. Space Erzgineering and Extreme Tevnperatuves. Beating The Heat Barrier. J, Taylor. (Royal Aircraft Establishment, Gt. Brit.), RAE Tech. Note Structures 286, July 1960, 14 pp + illus. A short survey is made of the characteristics of aerodynamic heating at supersonic speeds and of the properties of a typical aluminum alloy when exposed to increased temperatures for prolonged periods. With this information as a datum an estimate is made of the minimum combined weight of cooling and insulaWear, 4 (1961) 247-255
2s
Extreme Pressure Lubricants for Marine Gears. A. D. Newman. Pvoc. Inst. Mech. Engvs. (London), r74 (5) (1960) q-246. An extreme pressure oil may be used where the design per se requires a higher loadcarrying capacity than that provided by a normal oil and where its use will afford insurance against trouble.
4. MACHINE PARTS
Orthogonally Displaced Beatings. I. Donald F. Wilcock. ASLE Paper No. 60 LC-7, Oct. 1960, 1-7; 13 figs., I table, 9 refj. Journal bearings with cross sections consisting of circular arcs with centers displaced from the geometric bearing center along the midradius of the arc or lobe have been in use for many years. Examples are the “elliptical” bearing and the “three-lobe” bearing, the advantage sought being increased stabilitv under light loads without the reduced oil flow accompanying a reduced clearance ratio. The analysis was ‘carried out for a bearing having in cross section two arcs each subtending an angle of 15o’, an L/D ratio of &,
and with the arc centres each displaced from the geometric center by half the radial clearance. The Lubrication of Beatings at High Temperatures. E. G. Ellis. Sci. Lubrication (Londo,z), ~2 (1960) 16 + 6 pages. Much work on high temperature conditions and bearing ma.terial/lubricant combinations must be carried out before all the problems are solved. Promising combinations with certain limitations are: self-lubricating bearings, gas lubricated bearings, organic liquid “once-through” systems, solid lubricants and controlled atmospheres.
5. WEAR AND WEAR RESISTANCE 5.1. Conventional
Engineering
Mechanical Wear. G. W. Rowe. Appl. Mechanics Reviews, 13 (1960) 787-790; 24 refs. Principles of wear testing; selected experimental investigations; theories and laws of wear; corrosive wear and the influence of temperature; wear prevention or reduction. Hardening of Metals during Friction and the Strength of Steel during RepeatedlyXhanging Loadings (in Russian). D. A. Draigor and G. I. Valchuk. Sbornik Trudov Inst. Stroit. Mekh. Akad. Nauk S.S.R. 22 (1956) 93-99; Ref. Zlzur. Mekh., no. 2 (1959) Rev. 2077; Source: Appl. Mechanics Reviews 13 (9) (1960) TOI. An investigation is made on the influence of the process of hardening of the rubbing surfaces on the fatigue resistance and durability. A durability coefficient was determined. Polishing of the surface of the specimen with the elimination of centres of hardening resulted in the re-establishment of durability. Durability was not re-established by polishing when there was prolonged friction action on steels of a metastable structure. Abrasion Tests on Carpets Using Different Abtadants. Dorothy G. Clegg and S. L. Anderson. J. Textile Inst., Trans., 51 (9) (1960) T 385T 39r ; 4 figs., 5 tables, IO refs.
The effect of several abradants on nylon, viscose rayon, nylon/viscose blends and allwool carpets of the same construction was investigated on a Schiefer machine. While all abradants ranked the nylon/viscose carpets in the same order, the ranking of the all-wool carpet depended on the abradant used. Severe abradants, such as emery, show the least discrimination between different fibres. From a comparison with service trials by Sturlcy and Westhead (J. Textile Inst., 49 (1958) P 538) it follows that 509/o viscosenylon carpets have the highest wear resistance both in laboratory and service trials. The other compositions from 100% viscose with increasing quantities of nylon are given in the correct rank order with a BCA-type abradant. Wool carpets are classed by the machine still lower than in actual service. 5.2. Space Erzgineering and Extreme Tevnperatuves. Beating The Heat Barrier. J, Taylor. (Royal Aircraft Establishment, Gt. Brit.), RAE Tech. Note Structures 286, July 1960, 14 pp + illus. A short survey is made of the characteristics of aerodynamic heating at supersonic speeds and of the properties of a typical aluminum alloy when exposed to increased temperatures for prolonged periods. With this information as a datum an estimate is made of the minimum combined weight of cooling and insulaWear, 4 (1961) 247-255