Dynamics And Fatigue Life Research Of Gear Driving With Meshed Medium Belt

The gear driving has many advantages, such as large angular velocity ratio, high transmission efficiency, long service life, strong load-carrying capacity and compact structure, etc. And that make it becomes the most extensive transmission form in all kinds of mechanical equipment. The gear driving with meshed medium belt is a new kind of gear transmission which covers a closed annular flexible flat belt on the driven gear. The belt is medium between the meshing metal gears and it changes the gear contact pair from "high modulus-high modulus" to "high modulus-low modulus". This change reduced the vibration and noise and improved the transmission performance of the gear driving.1. The uncoupling vibration model of the gear driving with meshed medium belt was established based on the pure torsional vibration model and reasonable assumption. The mathematical equation was deduced and got the relationship between the system parameters based on the mathematic method. This will provide theory basis for the dynamic performance research of the new type gear driving.2. The modal analysis was preceded based on the finite element model of two kinds gear driving. The typical natural frequency and vibration mode showed that the natural frequency of the new type gear driving has obvious improvement and this will make it less likely to produce resonance. The stress of the gear has obvious decrease and this will reduce the fatigue damage of gear tooth surface. The new type gear driving has obvious advantages in the low speed and light load conditions.3. The thickness, elastic modulus and Poisson’s ratio of the belt was changed separately to study the affection to the gear driving. The analysis showed that the gear driving has better performance when the thickness is lmm. Less than lmm, the medium belt is easy to damage; bigger than1mm, the gear transmission is not smooth and the vibration increased. The vibration performance of the new type gear driving was better with the elastic modulus’ increase and decrease of the Poisson’s ratio. These factors must be taken into account comprehensively when select the material of the medium belt.4. To analyze the dynamic performance of the new type gear driving in the ANSYS Workbench software and extract the distribution map and response curve of the stress in the contact area. The analysis showed that the belt didn’t change the regularity of the stress during the gear transmission and this verified the rationality of the new type gear driving structure. The vibration amplitude and vibration cycle of the new type gear driving has changed because the reducing of the meshing stiffness and the increasing of the meshing damping caused by the medium belt.5. The fatigue life analysis of the new type gear driving has showed that the medium belt was the first to damage. Proposing measures to improve the fatigue life of the medium belt based on that analysis. This will provide theoretical basis for the selection and preparation of the medium belt.