Study Of Design Method And Injection Molding Technology For Plastic 3K-Ⅱ Micro Planetary Gear Reducer

Micro machine is one of the most promising technologies and will have significant effect on our society in the future.Micro planetary gear reducer is the main component of the diver for micro machine.In order to make the weight of micro machine light and to improve mass production of micro machine,the plastic micro planetary gear reducer is researched in this thesis.After detailed analysis of composition and operating principle of micro planetary gear reducer,specific structure of the 3K-â…¡planetary gear reducer is determined.And the strength of the designed 3K-â…¡planetary gear reducer is calculated by both experienced formula and software simulation.Then a set of injection mold for manufacturing the fixed internel gear and the output internel gear is designed.The proper processing parameters are also studied by simulating the injection molding course of the fixed internel gear and the output internel gear.Firstly,angular displaced method is adopted to design the micro 3K-â…¡planetary gear reducer.And parameters of the micro gears in micro 3K-â…¡planetary gear reducer whose modulus is 0.2 mm having a figure of 10 mm are computed.The previous design method for metal micro planetary gear reducer is checked and improved,and proper correction for the gear profile is introduced.A three-dimensional assembly model for the 3K-â…¡planetary gear reducer is established in Pro-E software to verify the operation of the designed 3K-â…¡planetary gear reducer.Secondly,after choosing POM as the material for the micro planetary gear reducer,the experienced formula are corrected to compute the strength of the sun gear which has the highest rotating velocity among the micro planetary gear reducer.And then the mechanical performance of the whole the micro planetary gear reduceris analyzed in ANSYS software. The strength analyses provide reference for application of the plastic the micro planetary gear reducer.Thirdly,the injection mold for manufacturing the fixed internel gear and the output internel gear is designed.The thickness of the plastic gear is more than 1 mm in order to make the micro planetary gear reducerhave enough strength,so the inserts for the mold cavity are processed by wire cutting,in stead of by lithography class technology. Finally,the injection molding course of the plastic internel gear is simulated by using Moldflow software to forecast possible molding defects and to determine the most appropriate processing parameters for improving the molding quality.