Theory of Grease Lubrication of Cylindrical Roller Bearing

Sasaki, Tokio; Mori, Haruo; Okino, Norio

doi:10.1299/kikai1938.25.1011

Cited by 3 publications

(4 citation statements)

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“…Fluids obeying this model are called Bingham plastic uids and exhibit a linear shear stress, shear-rate behaviour after an initial shear-stress threshold has been reached. Earlier attempt at theoretical analysis of grease lubrication was reported by Sasaki et al [6] who used a Bingham solid as a model for grease owing between non-deformed cylinders. Wada et al [7] used a Bingham solid as a rheological model to derive a modiÿed Reynolds equation and obtained a numerical solution for grease ÿlm shape and pressure distribution for elastohydrodynamic lubrication.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional lubrication flow of a Herschel-Bulkley fluid

Zhang

Khayat

Noronha

2005

Int. J. Numer. Meth. Fluids

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SUMMARYIn this paper three-dimensional lubrication ow of grease is analysed numerically. The lubrication ow conÿguration is formed by two ellipsoid rollers. The load is assumed to be light enough for the lubrication mode to be purely hydrodynamic. The uid behaviour is modelled using the HerschelBulkley model, and a two-dimensional modiÿed Reynolds equation is derived. The numerical solutions are obtained by using a hybrid spectral=iterative technique and the Galerkin projection scheme. The e ects of the material and geometrical parameters on pressure distribution are emphasized in the study. The investigation is conducted for a situation where the two ellipsoids are fully immersed in a grease lubricant. The e ect of the geometry on the pressure distribution is determined by varying the ratio of the semi-axes and the minimum gap of the two rollers, respectively. The e ect of the material parameters is examined by varying the power-law index and yield stress. It is found that the pressure distribution is strongly in uenced by the shape of the rollers, the size of the minimum gap of the rollers and the rheological parameters.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional lubrication flow of a Herschel-Bulkley fluid

Zhang

Khayat

Noronha

2005

Int. J. Numer. Meth. Fluids

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“…Grease behaves like discrete spherical soap particles dispersed in the base oil due to its passage through the contact inlet [8] and at higher velocities the viscosity of grease approaches that of the base oil [27]. Figure 5 shows the pressure profile and film thickness for a speed parameter value of 3.68 × 10 −9 at different values of W .…”

Section: Grease-to-base Oil Comparisonsmentioning

confidence: 99%

“…For the plug flow region of thickness h p and τ = τ 0 , substituting equations ( 6) and ( 7) into equation (27) and rearranging gives h p = 2τ 0…”

Section: Thickness Of the Plugmentioning

confidence: 99%

Thermoelastohydrodynamics of grease-lubricated concentrated point contacts

Karthikeyan

Teodorescu

Rahnejat

et al. 2009

Proceedings of the Institution of Mechanical Engineers, Part C:

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Isothermal and thermoelastohydrodynamic lubrication (TEHL) analyses of grease lubricated bearings are presented. A grease plug flow is formed in the conjunction that, with no shear at the boundaries with the solid surfaces, adheres to them in the region of high pressures under isothermal conditions. The elastohydrodynamic lubrication grease pressure distribution conforms fairly closely to that of its base oil alone, with the exception of inlet trail and pressure spike regions. The dependency of film thickness on speed (rolling viscosity) and load parameters for the base oil agrees with previously reported findings of the research community. For grease there are subtle differences with the base oil film thickness load and speed dependencies. However, it is clear that extrapolated oil film thickness formulae for oils can be used reasonably for the prediction of grease films, at least as a first approximation. The results presented agree well with optical interferometric measurements reported in the literature for grease-lubricated contacts at low temperatures and low surface velocities. TEHL analysis shows breakdown of the plug flow and significant reduction in film thickness, which can lead to changes in the regime of lubrication to mixed or boundary conditions.

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“…This model (or Oswald's model) is described by the relationship: (2) where p is the consistency coefficient and n the flow behaviour index. When n = 1. a Newtonian flow model with viscosity p is obtained.…”

Section: Power Law Flow Modelmentioning

confidence: 99%

Velocity fields in grease lubricated contacts

Mutuli

Bonneau

Frêne

1989

Lubrication Science

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This paper examines the behaviour of a grease lubricant in open contacts. Analytical expressions of velocity profiles for a Bingham fluid are presented for three cases: flow where all the film thickness is sheared; where a non‐sheared core zone is attached to one contact surface; and where a core zone floats in the middle of the film. An experimental study is described which used visualization through illumination across contact surfaces. Results are presented for two modes of operation: contact of cylinder and fixed plane surface, and pure rolling of two cylinders. In the former case, nine zones of operation are identified.

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Theory of Grease Lubrication of Cylindrical Roller Bearing

Cited by 3 publications

References 0 publications

Three-dimensional lubrication flow of a Herschel-Bulkley fluid

Three-dimensional lubrication flow of a Herschel-Bulkley fluid

Thermoelastohydrodynamics of grease-lubricated concentrated point contacts

Velocity fields in grease lubricated contacts

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