Study On Dynamics Characteristics Of Planetary Gear Transmission System And Vibration Noise Control For Bone Drill

Planetary gear transmission system has the characteristics of compact structure, large carrying capacity and has been widely used in automobile, shipbuilding, wind power equipment. In medical small type bone drill, planetary gear transmission system is the key functional parts to slow down and increase torque which performance is vital for the overall performance of bone drill. Complex dynamics properties of planetary gear transmission system, vibration and noise are the important factors which affect the service life of the system. At the same time, the vibration and noise is more obvious impact on doctors and patients and even on the quality of the surgery directly for medical equipment. It is useful to crack down the core technology of the planetary gear speed reducer, to reduce the dependence of imported equipments and to promote the design and manufacture development of medical bone drill in our country to investigate the dynamic performance of planetary gear transmission system on the actual working condition and the gear meshing incentive amount of contribution to the system noise.Based on planetary reduction part of medical orthopedic drill as the research object, the planet gear transmission system of vibration noise mechanism was deeply studied. It is guided of the method of reducer box body structure vibration noise control with planetary gear system dynamics simulation, bone drilling case acoustic finite element modal analysis, bone drilling and casing acoustic boundary element analysis method so as to reduce the vibration and noise and improve the dynamic performance of bone drill.This research have done the following work:the transmission mechanism of the planetary gear transmission in bone drill is analyzed; The noise generation mechanism of bone drill was analyzed combined with the basic theory of gear system dynamics. The three-dimensional model and the virtual prototype model for the planetary gear transmission part of the bone drill was developed. The main incentive of bone drill is analyzed under the condition of the rating power. The mode of the case of bone drill was analyzed and the main vibration mode was described. The response of the vibration is studied on the base of the dynamic simulation and modal analysis results under condition of the power rating. The structural noise prediction was carried out with the acoustic finite element and the acoustic boundary element method couped with the vibration results of the surface structure of casing, respectively. The sites of the sound pressure frequency spectrum was got and analyzed. At the same time, the acoustic modal contribution map and the contribution to the sound pressure larger modal order were determined. The structure noise control scheme was formulated and analyzed using the simulation method.