Lubricated loaded tooth contact analysis for spur gear pair

Abstract

Gears are key components to the operation of many machines and mechanisms.However, their presence often affects system efficiency and can lead to noise, vibration and harshness (NVH) issues. Therefore, improved efficiency and NVH refinement are the major drivers in the development of gearing systems. These requirements lead to significant efforts expended in the design of optimised gear pairs and their lubrication. Analytical and numerical gear analysis methods are limited to simplified methods such as dry contact conditions, use of basic classical Hertzian contact theory and finite element analysis in tooth contact analysis (TCA). Thus, the generation of more complex models would represent gear interactions, including lubricated contact analysis more realistically. Tooth Contact Analysis (TCA) is usually the first step for an in-depth; gear efficiency, NVH and durability analysis. Analyses described in open literature study tooth contact neglecting the effect of lubrication. In reality, contact mechanics and lubrication are closely inter-linked, requiring an integrated approach. This paper outlines a combined FEA-based TCA model with a lubricated contact mechanics analysis for real gear pairs, thus improving the prediction of gear pair efficiency, NVH and durability. An initial dry gear analysis with an estimated constant coefficient of friction in the contact is carried out. The results of this initial analysis provide input data for a subsequent tribological model in order to generate improved estimates of the contact friction for a new TCA. This approach leads to the integration of TCA and lubrication in an iterative manner.The gear pair geometry is measured using a Coordinate Measuring Machine (CMM) which takes into account manufacturing imperfections and real geometry within its measurement sensitivity of ±1.5 µm. This data is used in the TCA analysis.

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

“…The LLTCA approach is used to obtain the instantaneous contact geometry and sliding velocity of a pair of meshing involute teeth. A comprehensive description of LLTCA is provided by Oglieve et al [35] and Sivayogan et al [39]. Here, only a brief description is provided.…”

“…The heat flow balance (generated and conveyed through convection and conduction) can be stated as: (35) Replacing the rates of heat flow from the above relations in Equation ( 35) leads to the following relationship for the average effective contact temperature:…”

“…Realistic applied loads, meshing geometry and contact kinematics are necessary for tribological studies. These are obtained by lubricated loaded tooth contact analysis (LLTCA), highlighted in detail by Oglieve et al [35]. Unlike the usual TCA [36][37][38] LLTCA takes into account the effect of friction in sliding lubricated contact, as well as the measured profile of contacting surfaces including their real rough surface topography and any applied micro-geometrical form modifications [35].…”

“…These are obtained by lubricated loaded tooth contact analysis (LLTCA), highlighted in detail by Oglieve et al [35]. Unlike the usual TCA [36][37][38] LLTCA takes into account the effect of friction in sliding lubricated contact, as well as the measured profile of contacting surfaces including their real rough surface topography and any applied micro-geometrical form modifications [35]. The current paper also incorporates the assessment of contact integrity through the determination of the sub-surface stress field, including the effect of generated elastohydrodynamic lubrication (EHL) pressure spikes and friction.…”

Effects of lightweight gear blank on noise, vibration and harshness for electric drive system in electric vehicles

“…There is no friction on the contact surface and the effect of lubrication on LTCA is not considered; for the case of lubricated loaded tooth contact analysis, please refer to literature. 25 2. There are no losses due to hysteretic damping; for consideration of this loss, please refer to refer to literature.…”