Inefficiency predictions in a hypoid gear pair through tribodynamics analysis

Abstract

A tribo-dynamics model, predicting the conjunctional inefficiency and dynamic response of automotive hypoid gear pairs is presented. A dynamics model is coupled with an analytical friction model (viscous and boundary). The temperature rise at the centre of the conjunction is accounted for through use of thermal network model and Time Temperature Superposition (TTS) method, as well as the time varying geometry of the meshing gear teeth. Newtonian and non-Newtonian lubricant shear behaviour are both considered Surface topography measurements of a run-in pinions are obtained. Inefficiency calculations are performed for typical automotive drive cycle snapshots. Precisely measured lubricant shear characterstics for lubricants different blended viscosity modifiers and evolving surface topography are used in the study of transmission inefficiency. The integrated thermal-tribodynamic analysis is shown to distinguish between different viscosity modifier types, an approach not hitherto reported in literature.

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

“…However, it is shown that the convective heat removal rate, . Q cv is almost negligible in EHL contacts due to the thinness of the lubricant film and its low flow rate [34,40,41]. However, convective heat transfer by the lubricant flow is retained here for the sake of completeness of the analysis.…”

“…However, this is beyond the scope of the current analysis. As Morris et al [39] and Paouris et al [40] have noted, the heat flowing to the bounding contacting surfaces would need to overcome several thermal resistive barriers, as illustrated in Figure 7. Therefore, an analytical approach based on a thermal network model is deemed to be suitable for the purpose of the current study.…”

“…Therefore, the generated heat is conducted away through the lubricant layer adjacent to the contacting surfaces. The lubricant film thickness would be half that of the central film; thus, the corresponding thermal resistance becomes [40]:…”

State of the art of friction modelling at interfaces subjected to elastohydrodynamic lubrication (EHL)

“…The proposed statistical model showed that the friction force was determined by materials, pressure, and height distributions of asperities. Paouris et al [51] proposed an empirical tribo-dynamic model to predict the friction under a mixed boundary condition in a gear transmission; the friction consisted of the shearing of tribo-film as asperity summits and the dry sliding frictions over the contacted asperities. Figure 3 gave the model of surface contacts at the mixed lubrication conditions [24].…”

Analysis of transmission error and load distribution of a hoist two-stage planetary gear system

“…The multi-stage planetary transmission is extensively used in many engineering applications, such as large wind turbine gearboxes, automotive automatic transmissions, rotorcraft drive trains, and mining hoist, because of its compact structure and large transmission ratio. [1][2][3][4] However, as the inequality of load distribution for each planet, the multi-stage planetary gears often have more noise and vibration problems than single-stage planetary gears. [5][6][7][8][9] The load-sharing performance is poor due to restrictions of manufacturing precision, especially for low speed and over-loaded planetary transmission.…”