| Transmission is one of the most important components in the automobile transmission system,and its performance directly affects the automobile's power,fuel economy and comfort.In civilian vehicles,automatic transmissions have become the mainstream and are gradually developing toward "high quality,high efficiency,and intelligence." The epicyclic gear mechanism is the core that determines the performance of automatic transmissions.Therefore,in order to improve the performance of automatic transmissions,it is of great significance to study the innovative design theory of epicyclic gear mechanisms and design the automatic transmissions with independent intellectual property rights.This paper takes the epicyclic gear mechanisms in the automatic transmissions as the research object,and proposes a configuration synthesis method for epicyclic gear mechanisms based on the database of single multi-joint topological graphs.The 9-speed automatic transmissions are synthesized and a novel 9-speed automatic transmission is designed,which provides theoretical basis for the innovative design of automatic transmissions.Based on the topological representation model of the epicyclic gear mechanism,the existing epicyclic gear mechanisms used in automatic transmissions are transformed into double bicolor graphs.They are sorted and classified,and the conditions that must be satisfied for the epicyclic gear mechanisms applied to automatic transmissions are summarized.Based on the conversion relationship between the double bicolor graph and the basic graph,a novel synthesis method for epicyclic gear mechanisms is proposed.According to the existing epicyclic gear mechanisms and the database of single multi-joint topological graphs,the basic graphs of epicyclic gear mechanisms are obtained.The novel epicyclic gear mechanisms are synthesized through the basic graphs,and the obtained epicyclic gear mechanisms are used into the innovative design of automatic transmissions.The structural characteristics of Ravigneaux-type epicyclic gear mechanisms are summarized.Based on the conversion relationship between the double bicolor graph and the basic graph,a synthesis method for Ravigneaux-type epicyclic gear mechanisms is proposed combining with superposition method.Ravigneaux-type epicyclic gear mechanisms within 9 links are synthesized,and 9 double bicolor graphs are obtained.Through the function diagrams drawing method,41 function diagrams of Ravigneaux-type epicyclic gear mechanisms are obtained,which provides configuration support for the innovative design of Ravigneaux-type automatic transmissions.Aiming at epicyclic gear mechanisms used in 9-speed automatic transmissions,the link assortments satisfying the conditions are generated from the database of single multi-joint topological graphs,and the basic graphs are obtained.Based on the conversion relationship between double bicolor graph and the basic graph,double bicolor graphs are obtained,which are applied for configuration design of 9-speed automatic transmissions.A novel 9-speed automatic transmission is proposed,and the kinematics is analyzed by the lever analogy method.The characteristic parameters of the the novel 9-speed automatic transmission are given.Compared with the existing automatic transmissions,the feasibility of the new scheme is verified.The mechanical characteristics of the novel 9-speed automatic transmission are analyzed by the lever analogy method,and the torque expressions of the moving members under each gear is obtained.According to the analysis results,the torque and transmission power of each component are calculated numerically,and the power flow under each gear is obtained.The torque method is used to calculate the transmission efficiency under each gear.The kinematics and mechanical properties of the novel 9-speed automatic transmission are simulated by multi-body dynamics simulation software,and the prototype model is manufactured to carry out motion test.The feasibility of the novel 9-speed automatic transmission is verified. |
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