Error Analysis And Dynamic Response Of Two Teeth Difference Swing Rod Movable Teeth Drive

In the two teeth difference swing rod movable teeth drive,high power density is achieved due to the integration of the deceleration and output mechanism.Movable teeth are uniformly distributed in the circumferential direction combination in parallel mode to realize the multi tooth meshing.And pure rolling contact come true owing to the introduction of the multi local degree of freedom in the swing rod movable teeth.Therefore,it has some advantages such as compact structure,large deceleration ratio,high transmission precision,strong bearing capacity and so on.However,under the condition of multiple design parameters and multiple constraints,the transmission error has the characteristics of combination and randomness,which is increasingly appearing.Finally,it will affect the end precision of actuating device and cause the vibration and noise of the equipment.Accordingly,it is necessary to study the transmission error of the drive and the dynamic response based on the error excitation.Taking the single tooth meshing model as the research object,the instantaneous transmission ratio of each meshing pair was deduced by the velocity instantaneous center method.Based on the principle of functionary line increment means and the characteristics of multi-teeth meshing,the transmission error model of the drive mechanism was finally constructed.Through numerical simulation,the influence and the sensitivity of each error factor on the transmission error were revealed.According to the random distribution of the errors,the sampling formula for each error was derived.On these bases,the transmission errors were numerically counted by Monte Carlo simulation.And the influence of the random distribution characteristics of the errors and initial phase angles on transmission error distribution were discussed.Finally,the general method of precision design was discussed with an example.With SolidWorks design software,the three-dimensional prototype model of the drive mechanism was established.Based on the virtual prototyping technology,the accuracy of the prototype was verified via Adams motion simulation.Through random sampling of errors,three groups of virtual prototypes with different accuracy design schemes have been established.Combined with the simulation results of precision,the changing pattern and numerical distribution of transmission errors under different machining precision were summarized and the correctness of the precision design method was proved.Based on the hypothesis of small elastic deformation and the theory of deformation coordination,the forces of the meshing pairs was analyzed.Through Hertz contact theory,the tendency of meshing stiffness with the rotational angle of wave generator was obtained.Considering the effect of the error factors on the normal displacement of the meshing pair,the dynamic meshing force of each pair of meshing pairs was calculated.On the basis of the above all results,the torsional vibration equation with Stiffness excitation and error excitation was established according to the centralized parameter method.At last,the response of the angular displacement of the output axis under the influence of each random error was compared and analyzed by Runge-Kutta method.The results provide a theoretical reference for improving the transmission precision and dynamic performance of the drive pertinently and the distribution of machining precision of each component which is helpful to improve the design of the drive.