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Design of Fine-pitch Involute Gear Reducer with Small Tooth Difference and Reseach on Its Transmission Characteristics

Author: LiuDan
Tutor: TangDeWei
School: Harbin Institute of Technology
Course: Mechanical Design and Theory
Keywords: Fine-pitch Reducer with small tooth difference Optimal design Multi-toothmeshing Finite element analysis
CLC: TH132.46
Type: Master's thesis
Year: 2012
Downloads: 102
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Abstract

With China’s increasing emphasis on the space industry,the highly integratedspacecraft has become one of the important direction of development of spacetechnology. Harmonic reducer is the most widely used in the aerospace field, but in thespecial space environment stiffness is low due to its flexible wheel, in view of theadvantages of high transmission ratio, large output torque, high stiffness of the smalltooth difference reducer,the thesis puts forwards the design and transmissioncharacteristic research of fine-pitch involute small tooth difference reducer.Factors that impact meshing quality indicators are analyzed,and attributed to thediscussion of the pressure angle. A general algorithm is devised for solving optimizationof small tooth difference reducer driving parameters by genetic algorithm, optimaldesign is divided into two sections to discuss: multi-objective optimization of volume-reducer bearing capacity coefficient and optimization of meshing angle.Meshing interference criterions of small tooth difference gear pair arediscussed,and the mathematical model which takes minimum pressure angle asoptimization objective、meets the requirement of tooth-overlapping interference andcoincidence degree as constraints is established.Meanwhile,the lifespan,durability andthe quality of the processsed gear and so forth of the gear shaper cutter is decided by theparameter selection.In order to obtain better cutting property, the thesis establishes amathematical model aims at the optimization of maximum regrinding depth,which laysthe foundation for parameter optimal design of the shaper cutter. Based on above twomodels,an optimal design method using MATLAB Genetic Algorithm OptimizationToolbox is proposed,which solves the pressure angle optimization and the parameteroptimization of internal gear shaper cutter,thereby optimal parameters of the gear shapercutter is obtained,which satisfy every constraint.A practical example of fine-pitch involute small tooth difference reducer isdesigned according to design requirements,and the mechanical structure and sizeparameters are determined. The strength of reducer output mechanism is checked, andthe efficiency and backlash is calculated.The thesis discusses the phenomenon of multi-tooth meshing, establishes a multi-tooth meshing load distribution model of small toothdifference transmission and calculates the simutaneous meshing tooth number.Finally,finite element model of small tooth difference gear pair is established,which is analysedby software of ANSYS. By simulation analysis,we obtain the simutaneous meshingtooth number and stress nephogram of the gear pair,which verifies the result oftheoretical calculation. And then, modal analysis of the reducer is carried out, lowfrequency and vibration of tower structure is obtained which verifies the rationality ofdesign of reducer box.

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CLC: > Industrial Technology > Machinery and Instrument Industry > Mechanical parts and gear > The transmission mechanism > Meshing > Reducer and transmission
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