Thermal Effects in Slender EHL Contacts

Abstract

This study deals with experimental and numerical analysis of the thermal effects of slender elastohydrodynamically lubricated (EHL) contacts under high sliding. Thereby, the entrainment direction is along the major axis of the contact ellipse. Film thickness measurements were carried out on an optical EHL tribometer with a glass disk and steel roller. Numerical EHL solutions were obtained with consideration for non-Newtonian rheology and thermal effects. The results show that thermal effects can result in a strong viscosity wedge diverting oil flow to the contact sides. For high positive sliding, in which the glass disk moves faster, the influence of entrainment speed on minimum film thickness is almost negligible, while the film thickness shows a continuous decrease in gap length direction.

A quantitative analysis of double-sided surface waviness on TEHL line contacts

“…As experimental measurements of TEHL line contacts using the same lubricant are not available, we follow the common approach used in literature to validate the current CFD-FSI model against well-documented computational data from three different independent sources in literature, i.e. Hartinger et al [52,58], Tosic et al [71,72] and Srirattayawong [73]. Fluid properties and operating conditions for the cases mentioned above have been obtained from the corresponding references to make an accurate comparison.…”

Locus of lubricating weak point for the toroidal surface enveloping cylindrical worm drive

“…The method from the perspective of geometry and kinematics in this paper also has certain limitations. Compared with multi‐physics EHL analysis, for example, Reference 13, some physical factors such as pressure and viscosity are not considered in the current method. And, multi‐physics EHL studies usually give detailed results, including the distributions of pressure, temperature and oil‐film thickness, and so forth.…”

“…In fact, the Dowson formula, [14][15][16][17][18] in the elastohydrodynamic lubrication (EHL) theory, has been well established to compute the minimum thickness of oil film comparatively accurately and concisely between two linecontact elastic bodies in the isothermal EHL state, which can be represented as h min ¼ 1:6α 0:6 η 0 V ΣΝ ð Þ 0:7 E 00:03 R 0:43 w 0: 13 , ð1Þ…”

“…Chittenden et al 11,12 reviewed some classic work, and they conducted in‐depth numerical studies with the isothermal condition for the elliptical contacts and proposed formulae to predict the minimum and central film thickness for this whole range of contact. The slender EHL contacts are investigated, 13 combining various models and giving detailed EHL results. Wormgear is the drive element featured with slender EHL contacts, so Reference 13 has guiding significance for the study of EHL of worm drive.…”

“…The slender EHL contacts are investigated, 13 combining various models and giving detailed EHL results. Wormgear is the drive element featured with slender EHL contacts, so Reference 13 has guiding significance for the study of EHL of worm drive.…”