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The dynamics of ball bearings
360
SYSTEMATIC ABSTRACTS OF CURRENT LITERATURE
standard self-contained tapered roller journal bearings designed and manufactured for conventional service is described. Grease lubrication appears to be more than satisfactory for the intended application but seal modifications required are outlined. The transient bearing operating temperatures must not be permitted to exceed 275’F to avoid grease decomposition through the effects of structural phase changes and oxidation. BearIng Review. Anon., E.M.D., I4 (5) (1971) 469-489; 8 figs., 7 tables. Some important aspects of modem bearing technology are reviewed in four main sections. Section one deals with the bearing industry, trends in design, materials and lubricants; section two with prelubricated and oil-impregnated bearings; section three with plastic bearings and section four is a review of recent developments and applications of various types of bearing. A reference chart is included so that types of bearing referred to in the review may be easily identified. The Dyasmiea of Bail Bearings. C. T. Walters, JOLT, Ser. F, 93 (1) (1967) l-10; 8 figs., 10 refs. A comprehensive general analysis of the motions of balls and a ball separator with realistic lubrication is summarised. The equations of motion consider four degree of freedom balls and a six degree of freedom separator and are integrated numerically with a fourth order range Kutta scheme. Numerical results are presented for a particular spin axis gyro bearing configuration and show good agreement with experimental observations. Extensions of the analysis which are planned include a squeeze film lubrication model, consideration of non rigid separators and for roller bearings. Effect of a High Tractha Fluid on Skidding in a Higb Speed Roller Bearing. W. M. Kacmarsky and L. 0. Hewko, JOLT, Ser.F,93(1)(1971)11-16;10figs.,2tab1es,9refs. Under skid prone conditions laboratory tests have shown that cage skid in a lightly loaded roller bearing operating up to 3 million D.N. can be reduced from 65% to 3% by using a high traction fluid as lubricant in place of the specified oil. Art Analysieal Method to Predict Skidding in Thrust-loaded Angular-contact Ball Behags. T. A. Harris, JOLT, Ser. F, 93 (1) (1971) 17-24; 13 figs., 15 refs. Wear, 19 (1972) 355-367
An analytical method is presented to estimate the high-speed performance of fluid-film lubricated, thrust-loaded, angular-contact ball bearings. The accuracy of the method is demonstrated by comparison with published experimental data. It is suggested that the accuracy could be further improved by consideration of frictional heating in the contacts causing a temperature differential between inner and outer raceways and by consideration of non-Newtonian EHD lubrication phenomena. Ball Motion in Thrust-loaded Aagular-wntact Bearings with Coulomb Friction. T. A. Harris, JOLT, Ser. F, 93 (1) (1971) 32-38; 12 figs., 2 tables, 7 refs. Using a mathematical model analysis has demonstrated that situations emulating external characteristics of IRC and ORC can occur in thrustloaded, angular-contact ball bearings operating under the influence of Coulomb friction. From the analysis, ORC as an operational regime is more desirable than IRC when heat dissipation is a significant consideration. The conclusions cannot be applied to fluid film ball bearings which behave kinematically in a completely different manner. Simplified Analysis for Tractions Between Rolling !3lidiag ElastoI4ydrodynPmiccontlK!ts. J. W. Kannel and J. A. Walowit, JOLT, Ser. F, 93 (1) (1971) 3946; 5 figs., 25 refs. A simplified method for determining traction in elastohydrodynamic contacts is developed that has sufficient generality to take full advantage of the best available viscosity and rheology data for predicting traction. Yet it is sufftciently simple to enable rapid computer solution or analytical solution that can be incorporated into more complex analyses such as bearings dynamic studies. Evaluation of Electron Beam Welded Hollow Balls for High Speed Ball Bearings. H. H. Coe, R. J. Parker and H. W. Scibbe, JOLT, Ser. F, 93 (1) (1971) 47-59; 20 figs., 16 refs. Bearings using hollow ) inch SAE 52100 and 1l/16 inch MS0 steel balls as rolling elements were tested at 500 and 1000 pound thrust loads and shaft speeds up to 24000 r.p.m. The SAE 52100 balls showed little difference in torque, outer race temperature or fatigue life when compared with solid balls. The M50 balls showed only slight differences in torque and outer race temperature but a very significant decrease in rolling contact fatigue life compared with solid balls. The hollow balls failed in flexural fatigue due to stress concentrations on the weld areas.
SYSTEMATIC ABSTRACTS OF CURRENT LITERATURE
standard self-contained tapered roller journal bearings designed and manufactured for conventional service is described. Grease lubrication appears to be more than satisfactory for the intended application but seal modifications required are outlined. The transient bearing operating temperatures must not be permitted to exceed 275’F to avoid grease decomposition through the effects of structural phase changes and oxidation. BearIng Review. Anon., E.M.D., I4 (5) (1971) 469-489; 8 figs., 7 tables. Some important aspects of modem bearing technology are reviewed in four main sections. Section one deals with the bearing industry, trends in design, materials and lubricants; section two with prelubricated and oil-impregnated bearings; section three with plastic bearings and section four is a review of recent developments and applications of various types of bearing. A reference chart is included so that types of bearing referred to in the review may be easily identified. The Dyasmiea of Bail Bearings. C. T. Walters, JOLT, Ser. F, 93 (1) (1967) l-10; 8 figs., 10 refs. A comprehensive general analysis of the motions of balls and a ball separator with realistic lubrication is summarised. The equations of motion consider four degree of freedom balls and a six degree of freedom separator and are integrated numerically with a fourth order range Kutta scheme. Numerical results are presented for a particular spin axis gyro bearing configuration and show good agreement with experimental observations. Extensions of the analysis which are planned include a squeeze film lubrication model, consideration of non rigid separators and for roller bearings. Effect of a High Tractha Fluid on Skidding in a Higb Speed Roller Bearing. W. M. Kacmarsky and L. 0. Hewko, JOLT, Ser.F,93(1)(1971)11-16;10figs.,2tab1es,9refs. Under skid prone conditions laboratory tests have shown that cage skid in a lightly loaded roller bearing operating up to 3 million D.N. can be reduced from 65% to 3% by using a high traction fluid as lubricant in place of the specified oil. Art Analysieal Method to Predict Skidding in Thrust-loaded Angular-contact Ball Behags. T. A. Harris, JOLT, Ser. F, 93 (1) (1971) 17-24; 13 figs., 15 refs. Wear, 19 (1972) 355-367
An analytical method is presented to estimate the high-speed performance of fluid-film lubricated, thrust-loaded, angular-contact ball bearings. The accuracy of the method is demonstrated by comparison with published experimental data. It is suggested that the accuracy could be further improved by consideration of frictional heating in the contacts causing a temperature differential between inner and outer raceways and by consideration of non-Newtonian EHD lubrication phenomena. Ball Motion in Thrust-loaded Aagular-wntact Bearings with Coulomb Friction. T. A. Harris, JOLT, Ser. F, 93 (1) (1971) 32-38; 12 figs., 2 tables, 7 refs. Using a mathematical model analysis has demonstrated that situations emulating external characteristics of IRC and ORC can occur in thrustloaded, angular-contact ball bearings operating under the influence of Coulomb friction. From the analysis, ORC as an operational regime is more desirable than IRC when heat dissipation is a significant consideration. The conclusions cannot be applied to fluid film ball bearings which behave kinematically in a completely different manner. Simplified Analysis for Tractions Between Rolling !3lidiag ElastoI4ydrodynPmiccontlK!ts. J. W. Kannel and J. A. Walowit, JOLT, Ser. F, 93 (1) (1971) 3946; 5 figs., 25 refs. A simplified method for determining traction in elastohydrodynamic contacts is developed that has sufficient generality to take full advantage of the best available viscosity and rheology data for predicting traction. Yet it is sufftciently simple to enable rapid computer solution or analytical solution that can be incorporated into more complex analyses such as bearings dynamic studies. Evaluation of Electron Beam Welded Hollow Balls for High Speed Ball Bearings. H. H. Coe, R. J. Parker and H. W. Scibbe, JOLT, Ser. F, 93 (1) (1971) 47-59; 20 figs., 16 refs. Bearings using hollow ) inch SAE 52100 and 1l/16 inch MS0 steel balls as rolling elements were tested at 500 and 1000 pound thrust loads and shaft speeds up to 24000 r.p.m. The SAE 52100 balls showed little difference in torque, outer race temperature or fatigue life when compared with solid balls. The M50 balls showed only slight differences in torque and outer race temperature but a very significant decrease in rolling contact fatigue life compared with solid balls. The hollow balls failed in flexural fatigue due to stress concentrations on the weld areas.