The Deformation And Stress Analysis Of Flexspline In External Wave Electrostatic Harmonic Drive Systen

Electromechanical integrated electrostatic harmonic subminiature drive system is a novel concept of generalized compound drive system with the organic integration of the harmonic drive technology, electrostatic actuation technology and control technology. Its dynamic output can perform higher torque and lower speed compared with other micro-motors. External wave electromechanical integrated electrostatic harmonic drive system which put the flexspline outside the stator can increase the diameter of the flexspline while keeping the size of the system. Thus, the difficult problem in manufacturing flexspline will be solved, and it has important significance in the practical application of electromechanical integrated electrostatic harmonic subminiature drive system.The paper proposes electromechanical structural integrated principles of external wave electromechanical integrated electrostatic harmonic drive system, and analyses the operating principle. The transmission ratio is given according to the principle of harmonic drive.The formula for the electrostatic force is derived by using the electric field theory. The relationship between operating voltage and different structural parameters are obtained. Based on the elastic thin shell theory and selecting the displacement function which satisfying the closure condition in the circumferential direction, the analytic calculating formula of distortion and stress which is caused by the electric field are educed.Undetermined coefficients in the displacement function are obtained by using the iterative algorithm under introduction the free-free and clamped-free two boundary conditions. Then, the distribution of the displacements, internal forces and stresses are represented. Summarize the variation rules of displacements, internal forces and stresses with the coordinates of axial and circumferential.To improve the working performance of flexspline, respectively taking the two boundary conditions which the fixes end is built-in with two points or four points to analyze the displacements, internal forces and stresses of the flexspline. To sum up the basal rule which the operating voltage changes with the area of fixes end.The three-dimensional solid modeling of the system is finished successfully. The solid model of flexspline is given with ANSYS software and the distortion and stress under the electrostatic force are simulated. The simulation results confirm that the theory analysis is correct.