| In this paper, base on the problems that the larger contour dimension, the higher vibration and noise of the existing external parallel moving three-ring gear transmission mechanism, a new type of double crank input internal parallel moving gear transmission device is designed according to the basic principle of parallel moving gear transmission, the device adopts two-stage divided flow input, motion is output by three parallel moving external toothed plates with the inner gear ring meshing, it has the advantages of compact structure、low cost、 large transmission ratio、stable operation as well as the complete dynamic balance structure, it is a new type of driving device which be suitable for new requirements of modern machine on the transmission technology.This paper introduces the basic structure, the driving conditions and geometric design of the new type of internal parallel moving gear transmission device, the reasonable design parameters are determined and the solid model of the transmission device is established using Pro/ENGINEER software, make the motion simulation analysis. After testing, the device fits the requirements of mechanism kinematics. The elastic dynamical model of the new type of internal parallel moving gear transmission system is established, the system is divided into four subsystems which are the crank shaft Ⅰ、crank shaft Ⅱ、external toothed plates and output shaft with inner gear ring. By considering the elastic deformation of crank shaft, the elastic deformation of crank shaft planetary bearing and output shaft support bearing and the gear pair, the elastic deformation coordination relations between the various components are derived, again, according to the Newtonian second law of motion, the vibration differential equations of each subsystem are established. Then the whole elastic dynamic equation is obtained by taking the elastic deformation coordination relations into every vibration differential equation.In view of the mass, stiffness and damping matrices in elastic dynamic equation of system, the specific solution methods are given in paper. Through the MATLAB software programming, the natural frequencies of the new type of internal parallel moving gear transmission system are solved.Using Newmark method for solving the meshing forces of gears、crank shaft planetary bearing loads、crank shaft support bearing loads and output shaft support bearing loads, then proceeding dynamic simulation analysis, the results indicate:adopting double crank shaft input could ensure the certainty of motion; using the three-phase parallel moving external toothed plate transmission could reduce the loads of the input shaft and output shaft support bearings; planetary bearings are easy to produce fatigue pitting due to supporting bigger loads and the amplitude changes are also large. |
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