The lubricant shear modulus G and Ree-Eyring stress τ0 are determined in this work by using Roelands’, rather than Barus’, relationship for calculating the viscosity. When Roelands’ viscosity, elastic effects tend to be negligible, especially when inlet heating displacement of center pressure considered. These results illustrated examples which has been calculated, or lateral traction force obtained spinning was known. In some cases, indeed present, though much reduced, leads greater values...

The film thicknesses and pressures in elastohydrodynamically lubricated contacts have been calculated for a line contact by using an improved version of Okamura’s approach. new approach allows lubricant compressibility, the use Roelands viscosity, general mesh (nonconstant step), accurate calculations elastic deformations. is described, effects on thickness, pressure, pressure spike each improvements are discussed. Successful runs obtained at high (to 4.8 GPa) with low CPU times.

A novel analytical approach is proposed, uniform for ball and roller bearings, which takes into account 5 relative race displacements (3 translations: dx, dy, dz, 2 tilting angles: dθy dθz) to provide simple relationships calculating directly the resulting 3 bearing loads: Fx, Fy, Fz as well moments: My Mz. full coupling between all these forces considered. The maximum rolling element load Qmax, distribution Q(Ψ) 3-D dQ(Ψ, x′) at each roller-race contact slice are also given analytically. It...

Results given in this paper are threefold. In the case of Hertzian line contact, a new load/deformation relationship is derived analytically and use made thickness outer race section. A minor effect section shown. The exponent on deformation 1.074 (instead 1.1 usually accepted). calculated with successfully compared to results other published relationships also some available experimental results. For point useful relationships, obtained by curve-fitting, calculate easily load versus...

Smearing damage was created on cylindrical roller bearings (CRBs) using a laboratory test protocol that required alternating the load zone direction according to square wave function. The experimental goal compare wear protection afforded by various surface treatments, including vibratory superfinishing (ES20), black oxide treatment, and special tungsten carbide–reinforced amorphous hydrocarbon body coatings (WC/a-C:H). only bearing treatments did not smear in these severe tests were...

The miscellaneous components of bearing torque are described analytically. When the rolling element - race contact lengths similar, hydrodynamic ball component can be similar to tapered roller one. In bearings, sliding speed distribution encountered at ball/race is result two contributions: curvature in space ellipse and spinning effects. These contributions don't exist bearings. However, bearings subjected a roller/rib which compared analytically previous hall hearing components. final...

Abstract Basic relationships and physical concepts used for the development of a bearing dynamic tool (called CAGEDYN) are explained. Emphasis is put on some key affecting calculated cage impact forces: appropriate roller-cage contact stiffness (derived herein using novel equivalent stiffness), tangential hydrodynamic rolling pressure forces, effect roller normal load (for which new relationship given calculating load, even when there no interference between surface counter race or bridge...

Traction in lubricated elliptical Hertzian contacts with colinear speeds is studied. A method described to calculate the stresses, temperatures and shear strain rates distribution along across film. Visco elasto-plastic behavior of lubricant, convection, conduction effects pressure distributions are taken into account this method. Elastic energy release discussed. Shear modulus limiting stresses determined from experiment by curve fitting. Correlation between theory analyzed.

Hydrodynamic rolling force and moments in point contact have been studied detail using isoviscousrigid (IVR) elastohydrodynamic (EHL) models. Using fully flooded assumptions, curve-fitted relationships are given for calculating the IVR EHL hydrodynamic forces. Both proportional (or almost case) to 2 a, Hertzian length being perpendicular direction, also functions of dimensionless speed parameter. A single relationship has derived cover full range operating conditions with a smooth transition...

Hydrodynamic rolling force and moments in line contact have been studied detail using isoviscousrigid (IVR) elastohydrodynamic (EHL) models. Using fully flooded assumptions, curve-fitted relationships are suggested for calculating the IVR EHL hydrodynamic per unit length. At high speed light load, numerical results converge towards so that a single relationship has derived covering full range of operating conditions with rapid transition from to regime lubrication. Results obtained often...

Abstract This article begins by describing standard bearing life models in continuous rotation before going on to explain how the can be calculated for roller and ball bearings oscillatory applications. An oscillation factor aosc is introduced, which accounts oscillating stationary ring. numerically as a function of angle θ load zone parameter ɛ well parameters γ = D · cos α / dm ball-race osculation factors. Critical angles used Rumbarger are also employed at low values. Appropriate...

Analytical relationships are given for calculating in a planetary application the radial and orbital roller centrifugal forces usually taken by outer race cage-bridge, respectively. Each is described using two rotational degrees of freedom (dof), cage dof one dof. The model has been incorporated new tool, called CAGEDYN. Many graphical outputs shown example: needle bearing calculated at load speed nonplanetary with significant differences outlined. This tool particularly useful design...

Piezoviscous Rigid (PVR) film thicknesses, rolling and sliding traction forces formulas for the line point contact case have been derived. They used to study Rolling Element (R.E.)–cage pocket mechanism. As R.E. gets closer cage web, lubrication regime change gradually from PVR Elastic (PVE or EHD) when steel cages are used. If plastic used, moves Isoviscous (IVE) EHD regime. For conditions simulated herein, transition occurs at typical thickness values of order 0.5 micrometers substantially...

Based on analytical calculations assuming isothermal elastohydrodynamic (EHD) lubrication conditions, and curve-fitting of a thermal correction factor, new formula is proposed to calculate the sliding traction force developed in concentrated contact, nonlinear, viscoelastic lubricant undirectional sliding. When occurs rolling transverse directions (bidimensional sliding), simplified numerical method outlined by which components local shear stress are quickly calculated. The latter applied...

Models used in CAGEDYN and described Parts I II have been validated by comparing calculated measured values of the impact force a ball falling on beam, hydrodynamic rolling (due to Poiseuille flow or pressure gradient inlet an elastohydrodynamic lubrication [EHL] contact responsible for so-called race torque, even when operating under pure conditions), sliding traction EHL contact, bearing cage forces, slip. A description test rig measuring slip is presented. The correlation obtained...

An enhanced analytical approach is suggested for calculating three rolling element bearing loads Fx, Fy, and Fz as well the two tilting moments My Mz a function of five relative race displacements: translations dx, dy, dz, angles dθy dθz. A full coupling between all these displacements forces considered. This particularly recommended programming behavior in any finite analysis or multibody system dynamic tool, since only nodes are considered: one inner center, usually connected to shaft,...

Rolling contact bearing life is calculated using stresses at the surface and in volume. Surface account for profile misalignment as well asperity deformations. Sub-surface are beneath asperities (for defining of surface) deeper volume calculating The stress-life criterion adopted Dang Van one which local stabilized shear stress compared to material endurance limit defined a function hydrostatic pressure (itself pressure) but also residual hoop (due fit). A exponent c, order 4 (instead 34/3...

Based on a theoretical model and an experimental methodology for defining the friction torque lubricated conditions in modified thrust ball bearing having only three balls, authors experimentally investigated influence of lubricant parameter Λ mixed IVR (isoviscous rigid) EHL (elastohydrodynamic) lubrication conditions. The experiments were conducted using diameters 3 mm, 3.97 mm 6.35 loaded at 0.125 N, 0.400 N 0.633 N. Two oils viscosity 0.08 Pa·s 0.05 used rotational speed was varied range...

A recently proposed fatigue life model for rolling bearings has been applied to the study of lifetime reduction under conditions conducive microspalling. The presence a spike in EHD pressure distribution produces large shear stresses localized very close surface which may account early failure. This paper describes parametric effect such spikes. Accurate stress fields volume are calculated simulated spikes different height, width and position relative Hertzian distribution, as well lubricant...

Bearing life of the rotating race is analyzed numerically in case continuous rotation (L10_cont) and oscillatory application (L10_osc). The novelty this study lies calculation equivalent load number loading cycles that need to be defined an application. ratio aosc=L10_osc/L10_cont as oscillation factor given a function bearing zone parameter ε for different angles θ. It compared previously published results.

The stress based life model described in Paper I was calibrated using a large database of experimental results from global quality audit test program as well special development tests conducted for this validation effort. All used the calibration new were case carburized or through hardened tapered roller bearings. initial comparison to showed very good correlation with median ratio calculated close one. Higher accuracy compared traditional factor method also demonstrated by narrower...

Analytical relationships for calculating three rolling element bearing loads (Fx, Fy, and Fz) two tilting moments (My Mz) as a function of relative race translations (dx, dy, dz) angles (dθy dθz) have been given in previous paper. The approach was suggested any type, although it has recognized that the assumption constant element-race contact angle is not well supported by deep groove ball bearings (DGBB) or angular (ACBB). new described this paper addresses latter weaknesses accounting...

Roller/race misalignment and deformation are used for calculating analytically the pressure distribution along roller/race contact final load moment. Use is made of surface crowns race undercuts dimensions with their possible truncations at large or loads. The not symmetrical when occurs. This analytical development was by using a slicing technique in which local geometrical interference calculated each slice contact. A mix point line Hertzian solutions developed companion paper “Part I”...