Lubricated Loaded Tooth Contact Analysis and Non-Newtonian Thermoelastohydrodynamics of High-Performance Spur Gear Transmission Systems

Abstract

Energy efficiency and functional reliability are the two key requirements in the design of high-performance transmissions. Therefore, a representative analysis replicating real operating conditions is essential. This paper presents the thermoelastohydrodynamic lubrication (TEHL) of meshing spur gear teeth of high-performance racing transmission systems, where high generated contact pressures and lubricant shear lead to non-Newtonian traction. The determination of the input contact geometry of meshing pairs as well as contact kinematics are essential steps for representative TEHL. These are incorporated in the current analysis through the use of Lubricated Loaded Tooth Contact Analysis (LLTCA), which is far more realistic than the traditional Tooth Contact Analysis (TCA). In addition, the effects of lubricant and flash surface temperature rise of contacting pairs, leading to the thermal thinning of lubricant, are taken into account using a thermal network model. Furthermore, high-speed contact kinematics lead to shear thinning of the lubricant and reduce the film thickness under non-Newtonian traction. This comprehensive approach based on established TEHL analysis, particularly including the effect of LLTCA on the TEHL of spur gears, has not hitherto been reported in literature.

Fundamentals and Advances in Elastohydrodynamics: The Role of Ramsey Gohar

“…Since then, many solutions have been proposed for the EHL of point contacts across various applications, such as bearings and gears under transient, thermal and non-Newtonian conditions. They include those described in [16,[72][73][74][75][76][77][78][79][80][81][82][83][84][85]. Some researchers have employed alternative methods of formulation and solution, including finite elements, the complementarity approach or computational fluid dynamics (CFD) [86][87][88][89], including an early contribution by Ramsey and his co-workers [90].…”

Involute spline couplings in aero-engine: Predicting nonlinear dynamic response with mass eccentricity

“…It was validated that a formed thin lubricant film influences the dynamic response of the involute spline teeth. 24,25 However, there is no specific work to investigate the nonlinear dynamic response of the spline coupling considering lubrication. Meanwhile, in these studies, the overall meshing stiffness is a combination of the engagement of single and double pairs of teeth that imitate gear dynamics.…”

Three-dimensional dynamic modeling and analytical method investigation of planetary gears for vibration prediction

“…There are also some investigations concerning the lubricated contacts for spur gears. [14][15][16] Recently, lubricant and tooth surface temperature were taken into account by Sivayogan et al 17 and the effect of these issues were evaluated. Although such models are far more realistic than the former identical ones, dynamic modeling and analyses of one or more stages of planetary gears with lubricated contacts and temperature rise included are too complicated to get results with high precision.…”