Theoretical Analysis of Surface-Textured Elastomer Sleeve in Lubricated Rotary Sliding

Abstract

A soft elastohydrodynamic lubrication (SEHL) model is presented that consists of a stationary surface-textured soft elastomer sleeve and a rigid, smooth rotating shaft. The Reynolds equation and the equation of linear elasticity are solved simultaneously for the pressure distribution and viscous shear stresses in the fluid film and for the elastic stresses and deformations in the elastomer. An extensive parametric analysis is performed to evaluate the optimum parameters of the surface texturing for minimum friction coefficient. The transition from full hydrodynamic to mixed lubrication is also analyzed. It is shown that the model is also valid for predicting friction coefficient of various types of circumferential elastomer seals.

Evaluation of tribological properties of laser textured hardened tool steels

“…There are two reasons why the coefficient of friction reaches a low value in these cases: (a) surface texture re-duced the contact area between the test sample and compression platens and, (b) micro-dimples act as a micro-reservoir for liquid lubricant. According to the [28] the most important surface texture parameter is the ratio of the dimple height to the dimple diameter. According to the Ronen et al [29] this ratio value should be within the range of 0.1 to 0.2 in order to ensure the friction reduction in hydrodynamic lubrication regime.…”

Modeling of surface texturing in hydrodynamic lubrication

“…is relatively new [23,24]. Hence, differently from the previous applications, no experimental evidence has yet been accumulated to validate these models.…”

“…The basic modeling described above for mechanical seals can be easily modified to fit different applications. These modifications include, for example, solving a non-linear Reynolds equation for compressible fluids [11], solving the Reynolds equation simultaneously with a dynamic equation for piston rings [14] or with the equation of elasticity for elastomeric seals and bearings [23,24]. In the following few of these modifications are presented in more details.…”

“…This pressure may be sufficient to separate the initially interfering mating Fig. 14 (a) A schematic cross-section (not to scale) of the elastomer sleeve; (b) a cross-section through a single undeformed dimple [24].…”

“…Another advantage of texturing the soft rather than the rigid surface may be the prevention of wear of the soft elastomer by the harder surface features (protrusions or indentations) during unfavorable lubrication conditions. In this section the modeling of a textured elastomeric sleeve in rotary sliding [24] is described as an example for SEHL application.…”