多极式磁流变离合器温度场仿真与实验研究

Simulation and experimental research on temperature field of multipole magnetorheological clutch

针对磁流变离合器在滑差工作时因内部热量聚集而造成传递力矩下降甚至磁流变液失效的问题,采用仿真与实验相结合的方法对一种励磁线圈与永磁体相叠加的多极式磁流变离合器的温度分布特性进行研究。首先,分析了多极式磁流变离合器的热量来源,并建立了其温度场数学模型。然后,利用有限元模拟方法对多极式磁流变离合器在自然散热与强制风冷散热条件下的温度场进行了仿真分析。最后,通过搭建多极式磁流变离合器实验平台开展了温度特性测试实验。结果表明:多极式磁流变离合器在自然散热条件下连续滑差运行时,允许的最大滑差功率为160~170 W;在强制风冷散热条件下连续滑差运行时,允许的最大滑差功率为730~830 W;若瞬时滑差功率为3 000 W,则在磁流变液不失效的情况下允许的滑差时间为280 s。无论是瞬态还是稳态工况,多极式磁流变离合器的最低温度均出现在远离外壳体的动力输入盘轴端处,最高温度出现在第2个磁流变液工作间隙处。当采用强制风冷散热方式时,多极式磁流变离合器的温升速度降低,从而可延长其滑差运行时间。研究结果为磁流变装置的温度分布特性研究提供了理论参考。

Aiming at the problem that the transmission torque decreases or even the magnetorheological fluid fails due to internal heat accumulation in the magnetorheological clutch during slip operation, the temperature distribution characteristics of a multipole magnetorheological clutch with excitation coils and permanent magnets superimposed were studied by combining simulation and experiment. Firstly,the heat source of multipole magnetorheological clutch was analyzed, and its temperature field mathematical model was established. Then, the finite element simulation method was used to simulate and analyze the temperature field of multipole magnetorheological clutch under the conditions of natural heat dissipation and forced air-cooling heat dissipation. Finally, the multipole magnetorheological clutch experimental platform was built to carry out the temperature characteristic test experiment. The results showed that the maximum allowable slip power was 160-170 W when the multipole magnetorheological clutch operated continuously under the condition of natural heat dissipation;under the condition of forced air-cooling heat dissipation, the maximum allowable slip power was 730-830 W;if the instantaneous slip power was 3 000 W, the allowable slip time was 280 s without failure of magnetorheological fluid.Regardless of the transient or steady state conditions, the lowest temperature of the multipole magnetorheological clutch occurred at the shaft end of the power input disc far away from the outer housing, and the highest temperature occurred at the second magnetorheological fluid working gap.When the way of forced air-cooling heat dissipation was adopted, the temperature rise speed of the multipole magnetorheological clutch decreased, so as to prolong its slip operation time. The research results provide a theoretical reference for the study of temperature distribution characteristics of magnetorheological devices.