The Synthesis And Analysis Of Planetary Gear Transmission Mechanisms Of Ravigneaux Automatic Transmission

The planetary gear mechanisms(PGMs)are widely used in the field of automobile transmission because of the advantages of compact structure and high transmission power.Along with the advance of technology,automotive automatic transmissions are developed towards multivelocity,small and lightweight,and as one of the classic automotive automatic transmission,Ravigneaux-type PGM has significant advantages in the realization of the two indicators.However the study of automotive automatic transmission in our country starts late and is weak at basis,which restrains the development of Ravigneaux-type PGMs,especially in the field of configuration synthesis and speed arrangement.Therefore,it's significant to put forward a systematized theory on design for Ravigneaux-type PGMs.Based on the gear standard topological graphs,we propose a method of synthesis and a way of speed arrangement for Ravigneaux-type PGMs,and assess the working performance of new mechanisms,to establish an integrated design theory for Ravigneaux-type PGMs.Firstly,we analyze the structure characteristics and working principle of Ravigneaux-type PGMs,and introduce the related methods of synthesis and analysis.We propose the selecting principles of graphs and transforming principle of gear functional diagrams for Ravigneaux-type PGMs with 4 to 6 coaxial components based on the atlas database of topological graphs of gear kinematic chains,which obtain Ravigneaux-type PGMs with 4 to 6 coaxial components.On this basis,a synthesis method is proposed to synthesize the Ravigneaux-type PGMs with multi-coaxial components,and the results are verified through the atlas database.Secondly,we put forward the design requirement of Ravigneaux-type PGMs,and analyze the speed arrangement of Ravigneaux-type PGMs with 4 to 6 coaxial components by means of lever method.We mainly analyze the gear composition for Ravigneaux-type PGMs with 6 coaxial components and propose several new mechanisms.Then,we make the interference detection for the new mechanisms by plane graph method.Finally,we assess the working performances of a new mechanism,including the drive ratios,the ratio steps,speed of each links and efficiency analysis.Based on MATLAB,the parameters of the mechanism are determined,and compared with classic transmissions.