Performance characterization of a water-cooled magnetorheological fluid clutch with helical grooves

To address the issue of unstable output torque in magnetorheological (MR) clutch due to temperature rise, this paper proposes a water-cooled MR clutch with helical channels. Through magnetic circuit modeling and simulation, the distribution characteristics of the magnetic induction intensity within the working gap and its key influencing factors were systematically analyzed. Results show that when the excitation current reaches 3.0 A, the magnetic induction intensity in the working gap reaches ∼560 mT on the right side and 400 mT on the left side, with the magnetic field aligned perpendicular to the shear direction of the MR fluid to effectively utilize its rheological properties. The width of the cooling water gap has a significant impact on the magnetic circuit performance. Experimental results show that at 3.0 A, the output torque reaches 72.5 N m, with a deviation from the theoretical value of 9.375%. During a 300 s operation, the helical channel water cooling system maintains the working temperature stably below 80 °C, reducing the temperature rise by more than 30% compared to the uncooled condition, significantly delaying the thermal performance degradation of the MR clutch. This work provides a practical design with validated magnetic and thermal performance for high-duty MR clutch applications.