形状记忆合金与磁流变液交替传动性能研究

Study of Alternating Transmission Performance of Shape Memory Alloy and Magneto-rheological Fluid

针对磁流变液在高温下传动性能下降等缺点,提出一种形状记忆合金与磁流变液交替的传动方法。基于形状记忆合金的热力学效应,推导了弹簧挤压力与温度的关系式,并通过实验验证了方程的正确性;对传动装置的磁场进行有限元分析,得出了工作间隙沿径向的磁场分布;基于形状记忆合金弹簧热驱动特性,建立了摩擦转矩与挤压力、结构尺寸等参数的关系。结果表明,形状记忆合金弹簧产生的挤压力随温度升高而增加;温度低于40℃时,主要由磁流变液传递转矩,转矩可达9.14 N·m;温度在40℃~60℃之间时,磁流变液与形状记忆合金共同传递转矩,转矩可达13.24 N·m;温度高于60℃时,主要由形状记忆合金传递转矩,转矩可达9.40 N·m。随着温度升高,形状记忆合金能代替磁流变液传递转矩,装置能感知温度变化,实现交替传动。

In response to the shortcomings such as the degradation of transmission performance of magne⁃to-rheological fluid at high temperature,an alternating transmission method of shape memory alloy and magne⁃to-rheological fluid is proposed.Based on the thermodynamic effect of the shape memory alloy,the relationship between the squeezing pressure of the spring and the temperature is derived,and the correctness of the equation is verified by experiment;the finite element analysis of the magnetic field of the transmission device is carried out,and the magnetic field distribution along the radial direction of the working gap is derived;based on the ther⁃mal driving characteristics of the shape memory alloy spring,the relationship between the friction torque and the squeezing pressure,the structure size and other parameters is established.The results show that the squeezing force generated by the shape memory alloy spring increases with the increase of temperature;when the tempera⁃ture is lower than 40℃,the torque is mainly transferred by the magneto-rheological fluid,reaching 9.14 N·m;when the temperature is between 40℃and 60℃,the torque is transferred by the magneto-rheological fluid and the shape memory alloy together,reaching 13.24 N·m;when the temperature is higher than 60℃,the torque is mainly transferred by the shape memory alloy,reaching 9.40 N·m.As the temperature rises,the shape memory alloy can transmit torque instead of the magneto-rheological fluid,and the device can sense the temperature change to realize the alternating transmission.