Research On The Property Of A Magnetorheological Squeeze-Shear Mode And Its Applieation Simulation On A Clutch

Magnetorheological (MR) clutch, which overcomes the shortcomings of the traditional electromagnetic/magnetic/friction clutch, has the advantages of simple structure, putting out a stable torque, precise controllability, fast response, small energy, etc. But the present magnetorheological clutch that designed by shear mode can transmit the too small torque and have the too large volume. Therefore, MR clutch with high transmission performance has been becoming a very hot topic.MR fluid show higher stress capabilities in squeeze mode than other patterns(valve mode, shear mode), which can be used in transmission system of clutch. The mechanical properties of the MR fluids on squeeze, tension, squeeze-shear mode has been studied in this dissertation. The relationship between the mechanical property and the structure evolution has been discussed. A MR clutch on cone squeeze-shear mode is presented, and with the advantages such as, high torque, small volume, compact structure, good control effect and so on, the MR clutch is suitable for the transmission control of joint/separation in the fields of the aviation/spaceflight and vehicles. The main work and innovative contributions of this dissertation are as follows:(1) Main difficulties of MR clutch was analyzed. Based on squeeze-strengthen effect of magnetorheological fluid, a kind of MR clutch on squeeze-shear mode was developed. Mechanism of this method is introduced.(2) Experiment apparatus is constructed to test the quasi-static mechanical property of MR fluids under the external magnetic field. And the magnetic behavior of the equipment is analysed and optimized using a software of ANSYS.(3) The mechanical properties of shearing, tension, compression and shearing after compression are investigated under the external magnetic flux density. In the tension of MR fluid, the tensile stress can be affected by the magnetic field and the chain structure. During the compression of MR fluids, the compressive stress increase when the external magnetic field increases, and at the same time, the curves of compressive stress vs compressive strain, was measured under different magnetic flux density. The shear yield stress of MR fluids can enormously improve after compressed through improve the interconnections between particle chains.(4) Make use of statistical approach and based on microstucture, taking account of particle nonlinear magnetization and self-consistent magnetic moment, a microstucture model is proposed, which modifys the traditional magnetic dipole model. Based on the microstucture model, the composition and the relation of torque output was analyzed. Each main components of the MR clutch on cone squeeze-shear mode were made a detailed mechanical design and an assembly plan was given out. The optimization founded on the analysis of the simulation by Ansys results were studied. The result reveals that MR clutch on cone squeeze-shear mode has a good transmission performance with a low loss.