Study On Optimization And Simulation Of Planetary Gear Train For Earth Pressure Balance Shield Reducer

This project,“The high power density reducer of earth pressure balance shieldmachine”(2007AA041802), belongs to high technology research and developmentprogram of funded projects of China. The purpose is to optimize and simulate the threestage planetary gear reducer with a high-power for earth pressure balance shield. Thecutter head main reducer as the key to the main transmission components of the earthpressure balance shield machine is a three-stage planetary gear drive. It zoom torque tomeet the arduous task of high-load operation. The working condition is complicated, thepower is so high density, it require temperature rise is small, high efficiency, noise andvibration is low, and high reliability. Therefore, to carry out optimization design andsimulation analysis about the main gear box of the shield machine can help to improvethe performance of the shield reducer and further accelerate the localization process ofthe shield reducer.The research object is the NGW planetary gear system of the shield planetaryreducer in this paper. The main research contents and relevant conclusions are asfollows.①Unordered discrete values are changed into consecutive integers through theprocessing of the number of teeth and the modulus. Proposing an improved encodingway of real value and constructing the optimization models for planetary gear train withvolume smallest objective function, which can satisfy the conditions such as teeth,modification coefficient, interference and strength. The models are solved by means ofMatlab programming language through reasonable choosing the control parameters ofgenetic algorithm. The results show that the improved algorithm has better globaloptimization capability and converges to an optimal point in several startups. Thevolume has decreased21.056%under the constraints above.②Planetary carrier parametric model is established based on finite elementtechnology. Multi-objective optimization model with the volume smallest and themoment of inertia smallest is established by excluding non-sensitive parameters thoughtcorrelation analysis of design variables and considering the static and dynamiccharacteristics of the planetary carrier. Experimental of optimization model is designedbase on inscribed central composite design, precision response surface obtained byfitting. Three Pareto optimal solutions under the constraints is got by sampling response surface based on Shifted Hammersley Sampling technique.③Parametric model of the planetary gear train is established using APDL(ANSYS Parametric Design Language) though detail anglicizing the geometry of thegear. The stress distribution of the planetary gear at the moment when the sun wheel anda planet wheel meshed at the node is obtained thought selecting the appropriate contactstiffness to solve finite element model. The maximum contact stress is744.79MPa lessthan the allowable contact strength, so it meets the design requirements. The studyshowed that the stress distribution of the planetary gear train is complexity; there issingle and double tooth meshing at the same time. It is so different that stressdistributions of engaged region.