Research On Design And Manufacture Of Planetary Gear Reducer With Large Speed Ratio Asymmetric Herringbone Gear

In the situation where the actual engineering requires large transmission,the multistage parallel shaft transmission or the series of multistage NGW planetary gear trains are often used.These two schemes all bring about large volume,heavy mass and high failure rate because of the large number of transmission parts.So,in order to solve the above problems,the large speed ratio NGWN(?)type planetary transmission is adopted.Compared with the range of 20-500,it can shorten the transmission chain,reduce the failure rate and improve the reliability of the system.Based on the key basic research project of unmanned excavating equipment in deep dangerous coal seam(973 Plan)(2014CB046304),this paper designs and manufactures a prototype of NGWN(?)planetary transmission with large speed ratio asymmetric tooth shape according to the needs of the project,and sets up a related test bench to measure the efficiency and gear mesh frequency of the planetary gear train,and the specific research work is made below:(1)According to the power,speed and transmission ratio,the gear parameters of NGWN(?)type planetary transmission are designed.According to its basic parameters,the transmission efficiency is calculated by the meshing power method.The reason for the low transmission efficiency is that there is a circulating power flow between two pairs of inner meshing pairs.Using low-cost gear design principles,by optimizing the gear pair's displacement coefficient and tooth top height coefficient,the two-meshing pair's gear end face overlap is reduced,friction loss is reduced,and transmission efficiency is improved.(2)The curvilinear equation of asymmetric tooth profile is derived in detail,and the three-dimensional model of NGWN(?)planetary transmission with large speed ratio unsymmetrical tooth shape is established by combining MATLAB and SolidWorks.The model is decomposed into three pairs of meshing pairs into ANSYS,which is loaded according to the actual working conditions,and the tooth root bending stress and the contact stress of the tooth surface are calculated.According to the formula of the tooth root bending and the contact stress of the tooth surface in the mechanical design manual,the tooth root bending stress and the contact stress of the tooth surface are obtained from the same tooth number and modulus,and the symmetry gear is compared with the asymmetric gear,and the bending stress and contact stress of the non pair gear are found.Smaller than a symmetric gear.(3)The strength of the gear and other key parts in the planetary transmission mechanism is checked,and from the angle of lightweight design,the topology optimization of key components is optimized in the case of strength,and the optimal structural scheme is obtained.(4)The use of the extreme value method for the calculation of the tooth assembly dimension chain,obtained the tolerance of the relevant parts under the condition of meeting the assembly accuracy;the milling simulation simulation of the machining of the asymmetric gear tooth,the preparation of the processing process,the path of the knife,and the corresponding,The numerical control program,according to the laboratory five-axis machining center and workpiece blanks corresponding to the design of the fixture,the actual processing of the gear parts;and design the assembly process to guide the actual assembly.(5)According to the requirements of the project,relevant test benches were built,and the tests were carried out from two aspects of transmission efficiency and gear meshing frequency of the planetary gear train.The experimental results and the theoretical calculation results were compared to verify the feasibility of the experimental prototype.