Influence of Nozzle Layouts on the Heat-Flow Coupled Characteristics for Oil-Jet Lubricated Spur Gears

Abstract

Aiming to explore the influence of nozzle layouts on the lubrication and cooling performance of spur gears under oil jet lubrication conditions, this paper introduces a heat-flow coupled analysis method to predict the temperature field of the tooth surface with different nozzle layouts. Firstly, the friction heat formulas integrating the coefficient of friction and average contact stress are presented for calculating heat generation. We also present the impingement depth model, which considers the nozzle orientation parameters, jet velocity, and gear structure of the given spur gear pair for laying out the nozzle. Then, a heat-flow coupled finite element analysis method is exploited to resemble the jet lubrication process and gain the gear temperature characteristics. Finally, the numerical results of this model compare well with those of the experiments, showing that this heat-flow coupled model provides accurate temperature prediction, indicating that the nozzle layouts determined as a function of the oil jet height, deviation distance, and oil injection angle significantly influence the lubrication and cooling performance. Further, this study also reveals that the lubrication performance in cases where the nozzle approaches the side of the pinion is relatively superior.

A New Experimental Methodology to Study Convective Heat Transfer in Oil Jet Lubricated Gear Units

“…[5] proposed a model to predict the overall temperature of a mechanical transmission; (ii) Long [6] simulated the temperature of gear teeth at high speeds, taking into account the effects of gear geometry, rotational speed, and lubrication conditions; (iii) Townsend et al [7] developed a computer program for predicting gear-tooth temperatures and the importance of oil jet cooling in preventing scoring, with the need for an experimental determination of heat-transfer coefficients. In addition to the above-mentioned studies, the works of Xing C. [8], G. Niemann [9], Peng Jie [10], and Duan Yang [11] showed that for gears operating under high speeds, a pressurized oil jet is required to provide adequate cooling and prevent gear failure caused by high bulk temperatures.…”