Development and Analysis of a Novel Electric Motor Rotor Shaft Cooling System

This paper introduces a novel shaft jacket cooling system to enhance the thermal management of high-performance electric traction motors. Empirical analysis demonstrates the superior thermal performance of this innovative concept compared to conventional shaft cooling systems. A detailed Computational Fluid Dynamics (CFD) analysis further investigates the shaft thermal behavior. A lumped parameter model is developed for the shaft and rotor lamination assembly, enabling accurate prediction of magnet temperatures. The model's thermal resistances are calibrated using 2D Finite Element Analysis (FEA). Finally, motor-level analysis confirms that the proposed shaft jacket cooling method achieves a significant reduction in magnet temperatures (up to 20°C) compared to state-of-the-art cooling techniques, while maintaining effectiveness across a wide speed range.