ASME International
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Component Hardness Differences and Their Effect on Bearing Fatigue The five-ball fatigue tester and full-scale rolling-element bearings were used to determine the effect of component hardness differences of SAE 52100 steel on bearing fatigue and load capacity. Maximum fatigue life and load capacity are achieved when the rolling elements of a bearing are one to two points (Rockwell C) harder than the races. There appears to be an interrelation among compressive residual stresses induced in the races during operation, differences in component hardness, and fatigue life. Differences in contact temperature and plastically deformed profile radii could not account for differences in fatigue life.
ASME International - Tập 89 Số 1 - Trang 47-54 - 1967
Ball Motion in Thrust-Loaded, Angular Contact Bearings With Coulomb Friction
ASME International - Tập 93 Số 1 - Trang 32-38 - 1971
Dynamics of Rolling-Element Bearings—Part IV: Ball Bearing Results Dynamic simulations of the performance of a ball bearing are presented in terms of the general motion as obtained by integrating the differential equations of motion of the various bearing elements. It is shown that bearing misalignment significantly influences the ball/cage and race/cage interaction and, hence, the stability of cage motion. The increased radial to axial load ratios promote skidding which couples with the lubricant behavior to impose accelerations on the ball which ultimately influence the ball/cage interactions. Hence, the lubricant behavior and the large load variation on the balls play dominant roles not only in determining the extent of skidding but also in establishing the overall stability of the cage motion.
ASME International - Tập 101 Số 3 - Trang 319-326 - 1979
An Analytical Method to Predict Skidding in Thrust-Loaded, Angular-Contact Ball Bearings
ASME International - Tập 93 Số 1 - Trang 17-23 - 1971
Dynamics of Rolling-Element Bearings—Part III: Ball Bearing Analysis An analytical formulation for the generalized ball, cage, and race motion in a ball bearing is presented in terms of the classical differential equations of motion. Ball-race interaction is analyzed in detail and the resulting force and moment vectors are determined. The ball-cage and race-cage interactions are considered to be either hydrodynamic or metallic and a critical film thickness defines the transition between the two regimes. Simplified treatments for the drag and churning losses are also included to complete a rigorous analytical development for the real-time simulation of the dynamic performance of ball bearings.
ASME International - Tập 101 Số 3 - Trang 312-318 - 1979
Theory of Lubrication With Ferrofluids: Application to Short Bearings The momentum equations are written for viscous fluids exhibiting magnetic stresses. The velocity profiles are deduced; then from continuity, a pressure differential equation, equivalent to Reynolds equation is obtained. This equation is discussed with emphasis on the case when magnetic stresses derive from a potential, also when the pyromagnetic coefficient vanishes. The boundary conditions for lubrication problems are then formulated. In particular, short bearings with ferromagnetic lubricants are considered. A numerical example yields the pressure diagrams at low and moderate eccentricity ratios and for different speeds. In conclusion, it is shown that ferromagnetic lubricants may improve substantially the performance of bearings operating under low loads and/or at low speeds. However, a correct variation of the magnetic field, toward the center of the lubricated area, is required. Under such conditions, the extent of the active area of the film is increased and bearing stiffness and stability are improved.
ASME International - Tập 104 Số 4 - Trang 510-515 - 1982
A Bulk-Flow Theory for Turbulence in Lubricant Films The purpose of this study on the turbulent lubricant film is: 1 To give a brief outline of a new theory called bulk-flow theory; 2 To investigate to what extent results of theories based on law of wall and mixing length concept agree with the newly developed theory; 3 To provide a theoretical basis for the design of bearings lubricated by fluids of low kinematic viscosity.
ASME International - Tập 95 Số 2 - Trang 137-145 - 1973
Hydrodynamic Lubrication of Hydrostatic Extrusion An analytical model for the hydrodynamic lubrication of hydrostatic extrusion is developed. This includes the effect of viscous heating on the film formation process and the effect of viscous and plastic heating on the friction and film thickness variation in the work zone. Theoretical predictions of film thickness and extrusion pressure show good agreement with experimental measurements for aluminum billets lubricated with castor oil.
ASME International - Tập 98 Số 1 - Trang 27-31 - 1976
Lubricant Flow in a Plastohydrodynamic Work Zone An analysis of the lubricant flow in zones of plastic deformation is developed. This includes the effects of different surface temperatures and shear heating within the lubricant film. Thermal effects on the lubricant velocity and temperature profile, traction and volume flow rate are described. The difference in surface temperatures plays a dominant role in deciding the variation of lubricant film thickness with position and time in metal forming operations.
ASME International - Tập 98 Số 1 - Trang 16-21 - 1976
A Hydrodynamic Lubrication Theory for Strip Rolling Including Thermal Effects A model of hydrodynamically lubricated cold rolling including thermal and pressure effects on the lubricant is developed in this paper. The hydrodynamic film thickness is calculated as well as the work zone pressure and shear stress distribution for several conditions assuming that the lubricant behaves as a Newtonian fluid. Pressure measurements made with vapor-deposited thin-film transducers on the roll surface are used for experimental comparison.
ASME International - Tập 97 Số 1 - Trang 4-12 - 1975
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