Disposable Harmonic Reducer With High Power To Weight Ratio

The purpose of this study is to develop a high power-weight ratio reducer for a certain type of steering gear system.The reducer has the characteristics of large reduction ratio,high transmission accuracy and large load torque.Compared with the same grade reducer designed by conventional design method,the size requirement of the harmonic reducer developed in this paper is more stringent.Therefore,on the basis of comparing various transmission modes which can achieve large reduction ratio and small volume,the lightweight harmonic transmission mode is selected.Considering the shorter service life of the rudder system,the disposable mechanical design theory is adopted to design the rudder system,and the research work is carried out in two directions: increasing the allowable load and designing the new structure.Firstly,through the stress controlled low cycle fatigue test,the allowable load of flexible wheel material under the theory of disposable machinery is obtained.Based on this,the transmission ratio distribution and the overall structure of the reducer are designed,and the commercial finite element analysis software ANSYS is used to analyze the stress of the flexible wheel in the weak link of the harmonic reducer.The first one is to give full play to the strength of the material,increase the load it bears,and reduce the size of the structure.However,this scheme still uses dual-wave transmission,because of the tooth number constraints,the scheme is difficult to achieve a larger reduction in size,so this paper also improves the structure form,single-wave wave generator as the core,designed the second structure scheme.Secondly,for the double-wave wave generator,the elliptical cam structure with the best transmission performance is selected,while for the single-wave generator,the semi-elliptical semi-circular cam structure is selected.In order to reduce the axial dimension of one-off harmonic reducer,the flat output structure is adopted in both schemes.After completing the overall design and checking,the transmission accuracy of the one-off reducer is calculated,and the life of the flexible wheel is calculated according to the load of the flexible wheel and the low cycle fatigue test data of stress control.Finally,according to the two design schemes,two disposable harmonic reducers are manufactured and compared with the conventional design method in terms of volume and quality.The running-in test of two newly designed harmonic reducers is carried out,and the transmission accuracy test and load torque test are carried out with the special harmonic drive chain tester.The test results show that the dual-wave type disposable harmonic reducer has better performance and can meet the requirements of high power-to-weight ratio.The single-wave type disposable harmonic reducer still needs further research on its bias load.