Research on active lubrication control strategy of battery electric vehicle reducer based on oil film thickness

In the reducer field, lubrication is used to improve working reliability. However, the current splash lubrication is prone to excessively high reducer lubricating oil temperature under some harsh working conditions, resulting in reduced oil film thickness on the gear meshing tooth surface, mixed lubrication in local areas, aggravated tooth surface wear, and even failure. Therefore, this paper proposes an active lubrication control strategy for battery electric vehicle reducers based on oil film thickness to improve the reducer's operational reliability. Firstly, an accurate reducer thermal network temperature calculation model is established based on analyzing heat generation characteristics. Then, the minimum oil film thickness of the meshing tooth surface and its influencing factors under different working conditions are examined, and the dynamic target optimization temperature is determined. Finally, an active lubrication control strategy for battery electric vehicle reducers based on oil film thickness is proposed. The results show that, compared with the traditional splash lubrication method, the operating time of the lubricating oil temperature exceeding the safe temperature in the active lubrication method under the combined WLTC working condition is reduced from 29.6 % to 2.7 %, indicating the effectiveness of the active lubrication control strategy proposed in this study. • Based on the analysis of the heat generation characteristics of the reducer, an accurate thermal network temperature analysis model was established. • The accuracy of the thermal network temperature analysis model was verified through simulation and experiments. • An active lubrication control strategy based on oil film thickness was proposed. • The simulation results show that the operating time of the lubricating oil temperature exceeding the safe temperature in the active lubrication mode under the combined WLTC condition is reduced from 29.6 % to 2.7 %.