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Misalignment effects in 180° partial journal bearings
SYSTEMATIC
ABSTRACTS
OF CURRENT LITERATURE
lubricant failure was mainly due to surface distress by wear and superficial pitting. The Effect of Oil Supply oa Cage and Roller Motion in a Lubricated Roller Bearing. R. J. Boness, JOLT, 92 Ser. F (I) (1970) 39-53; 21 figs., 8 refs. Experimental results indicate that oil supply can have a significant effect on cage and roller motion; restricting the oil supply reduces the amount of cage and roller slip. A theoretical analysis is presented which enables cage and roller motion to be predicted. The theoretical results imply that reducing oil supply to the minimum value to maintain hydrodynamic conditions reduces cage slip by up to 75% of the fully oil-flooded value. In many practical situations it is not possible to reduce drastically the lubricant supply which is required for cooling. The analysis also illustrates the significant role of bearing load and thus a compromise must be made between the roller loading necessary to reduce cage slip to an acceptable value and thecorresponding reduction in life due to increased load. Lubricant as a Coolant in High-speed Gear Couplings. L. Filepp,JOLT, 92Ser. F, (I) (1970) 178-179; 1 fig. It was found that the amount of frictional heat developed in a high-speed gear coupling and therefore the flow rate of cooling lubricant are proportional to horsepower transmitted and not to speed. This is confirmed by service experience therefore the chart provided may be considered a good practical guide to lubricant requirements for continuously lubricated couplings. 3.3. Solid lubricants Dry Lubrication. E. J. Robbins, Tribology, 3 (2) (1970) 84-88; 3 figs., z tables, 22 refs. A short review of the types of dry lubricants, t6eir advantages and disadvantages and applications. 4. MACHINE
PARTS
Analysis and Performance of the Gaslubricated Tilting-pad Thrust Bearing. W. Shapiro and R. Colsher, ASLE Trans., 12 (3) (1969) 206-215; 14 figs., 3 tables, 6 refs. A numerical treatment for analysing the tilting-pad thrust bearing is presented together with extensive performance information for a particular pad geometry. An optimum hydrodynamic crown profile and related dimensions are determined. A design procedure and example are given.
157
Misalignment Effects in 180” Partial Journal Bearings. J. R. Stokley, ASLE Trams.. r.z (3) (1969) z16-226; IZ figs., 6 tables, 12 refs. The performance of centrally-loaded liquidlubricated 180” partial hydrodynamic journal bearings with shaft misalignment is considered. The results of numerical calculations for L/D ratios of I, 4 and $ and a range of all angles are presented which enable the designer quantitatively to assess the various effects of misalignment. The effect of misalignment on bearing performance is discussed and examples given. The Effect of Viscosity Variations with Temperature on the Performance of Spiralgroove Bearings. J. Bootma, ASLE Trans., 12 (4) (1969) 287~296: 8 figs., 8 refs. The load capacity and power loss of spiralgroove bearings, lubricated with a Newtonian incompressible liquid with a viscosity depending on temperature only are determined by solving the continuity and momentum equations analytically and the energy equation for the ridges and the grooves numerically. The effect of the thermal entrance region is investigated. Calculation of Wear on Ball Bearings Working in an Aqueous Medium. A. G. D’Yakova and E. F. Neponmyashchii, Russian Eng. J., 49 (7) (1969) 23-26; 3 figs., I table, 6 refs. (Transl. by P.E.R.A. of Gt. Britain of Vest%. Mascha’laosir., 49 (7) (1969) 21-23.) A method for calculating the wear on radial ball bearings for the case of two-point contact in an aqueous medium is described which makes it possible to estimate the wear rate from the physical and mechanical properties of the materials. The effect of loading in the range of contact stresses from 12~250 gf/mmz is considered. At stresses around 180 #/mm2 there is a jump caused by a change in the frictional conditions at the contact by the displacement of water from the surface. Further work is required in the experimental determination of the coefficient of friction particularly at lower loads typical of the working conditions in an aqueous medium. Load Ratings and Fatigue-life Prediction for Ball and Roller Bearings. J. I. McCool, JOLT, 92 Ser. F, (I) (1970) 1622; 5 figs., 12 refs. A review of current rolling bearing load rating and life prediction practices is given based on the American Standard Association (ASA) standard method. Life factors in addition to those encompassed in the ASA standard are discussed and a more general rolling contact fatigue theory is outlined. As Wear, r6 (1970) 151-163
ABSTRACTS
OF CURRENT LITERATURE
lubricant failure was mainly due to surface distress by wear and superficial pitting. The Effect of Oil Supply oa Cage and Roller Motion in a Lubricated Roller Bearing. R. J. Boness, JOLT, 92 Ser. F (I) (1970) 39-53; 21 figs., 8 refs. Experimental results indicate that oil supply can have a significant effect on cage and roller motion; restricting the oil supply reduces the amount of cage and roller slip. A theoretical analysis is presented which enables cage and roller motion to be predicted. The theoretical results imply that reducing oil supply to the minimum value to maintain hydrodynamic conditions reduces cage slip by up to 75% of the fully oil-flooded value. In many practical situations it is not possible to reduce drastically the lubricant supply which is required for cooling. The analysis also illustrates the significant role of bearing load and thus a compromise must be made between the roller loading necessary to reduce cage slip to an acceptable value and thecorresponding reduction in life due to increased load. Lubricant as a Coolant in High-speed Gear Couplings. L. Filepp,JOLT, 92Ser. F, (I) (1970) 178-179; 1 fig. It was found that the amount of frictional heat developed in a high-speed gear coupling and therefore the flow rate of cooling lubricant are proportional to horsepower transmitted and not to speed. This is confirmed by service experience therefore the chart provided may be considered a good practical guide to lubricant requirements for continuously lubricated couplings. 3.3. Solid lubricants Dry Lubrication. E. J. Robbins, Tribology, 3 (2) (1970) 84-88; 3 figs., z tables, 22 refs. A short review of the types of dry lubricants, t6eir advantages and disadvantages and applications. 4. MACHINE
PARTS
Analysis and Performance of the Gaslubricated Tilting-pad Thrust Bearing. W. Shapiro and R. Colsher, ASLE Trans., 12 (3) (1969) 206-215; 14 figs., 3 tables, 6 refs. A numerical treatment for analysing the tilting-pad thrust bearing is presented together with extensive performance information for a particular pad geometry. An optimum hydrodynamic crown profile and related dimensions are determined. A design procedure and example are given.
157
Misalignment Effects in 180” Partial Journal Bearings. J. R. Stokley, ASLE Trams.. r.z (3) (1969) z16-226; IZ figs., 6 tables, 12 refs. The performance of centrally-loaded liquidlubricated 180” partial hydrodynamic journal bearings with shaft misalignment is considered. The results of numerical calculations for L/D ratios of I, 4 and $ and a range of all angles are presented which enable the designer quantitatively to assess the various effects of misalignment. The effect of misalignment on bearing performance is discussed and examples given. The Effect of Viscosity Variations with Temperature on the Performance of Spiralgroove Bearings. J. Bootma, ASLE Trans., 12 (4) (1969) 287~296: 8 figs., 8 refs. The load capacity and power loss of spiralgroove bearings, lubricated with a Newtonian incompressible liquid with a viscosity depending on temperature only are determined by solving the continuity and momentum equations analytically and the energy equation for the ridges and the grooves numerically. The effect of the thermal entrance region is investigated. Calculation of Wear on Ball Bearings Working in an Aqueous Medium. A. G. D’Yakova and E. F. Neponmyashchii, Russian Eng. J., 49 (7) (1969) 23-26; 3 figs., I table, 6 refs. (Transl. by P.E.R.A. of Gt. Britain of Vest%. Mascha’laosir., 49 (7) (1969) 21-23.) A method for calculating the wear on radial ball bearings for the case of two-point contact in an aqueous medium is described which makes it possible to estimate the wear rate from the physical and mechanical properties of the materials. The effect of loading in the range of contact stresses from 12~250 gf/mmz is considered. At stresses around 180 #/mm2 there is a jump caused by a change in the frictional conditions at the contact by the displacement of water from the surface. Further work is required in the experimental determination of the coefficient of friction particularly at lower loads typical of the working conditions in an aqueous medium. Load Ratings and Fatigue-life Prediction for Ball and Roller Bearings. J. I. McCool, JOLT, 92 Ser. F, (I) (1970) 1622; 5 figs., 12 refs. A review of current rolling bearing load rating and life prediction practices is given based on the American Standard Association (ASA) standard method. Life factors in addition to those encompassed in the ASA standard are discussed and a more general rolling contact fatigue theory is outlined. As Wear, r6 (1970) 151-163