The Design And Study On Motion Mechanism Of Automotive Sunroof Based On Virtual Prototype Technology

With the development of automotive industry and improving people's living standard, the automotive manufacturers and drivers pursue to improve the driving environment inner the car and driving safety. The air quality inner car has a great effect on the driving comfort and safety. The air condition can adjust the temperature and humidity inner car to some extent. But the ventilation effect is not good, because it is a close space in the car. And it can also result in asymmetric distribution of the air and humidity. With the side windows the ventilation can also been done, but it will result in great wind noise and air eddy, which will increase the driving resistance and the fuel consumption. The sunroof has the advantage of gut lighting, improved air quality in inner car, more energy saving and it can also make the car looking more luxurious. Therefore, now the sunroof becomes more and more popular.In the past five years, the Chinese automotive industry developed very fast. The turnout of passenger car has broken through 2.5 million per year. In order to meet the requirement of customer, the turnout of passenger car with sunroof increased rapidly. At present 80 percent share of china sunroof market is monopolized by Webasto Company. Although there are more than ten local corporations in Guangdong and Zhejiang Province etc., who are producing sunroof for passenger car with a small batch, all of them have no independent product development capacity and their competitive ability is very bad. They are still in the phase of copy or imitation. In order to break the technology quarantine and market monopolization, enhance the local sunroof corporations'competition ability; it is necessary to build a sunroof independent development platform with modern design technique.According to the Project of sunroof independence development platform for passenger car with modern design technique, the research object in this paper is the sunroof drive mechanism. We used the modern design technique to solve the key technical problems for sunroof development, researched the new development process for car sunroof development with modern design method. And we also built the parameter simulation model of sunroof motion mechanism for the optimization, which can supply technical support for variation sunroof development. The following is the main content:1. The reverse engineering method was used to get the geometrical parameters of the typical structure parts of the sunroof, such as glass assemble, deflector and drain system which are very difficult to be modeled with the forward design. After the measure we achieved the cloud datum. After the analysis, processing and surface restructure with software CATIA we achieved the 3D digital model from the cloud datum. All of the other parts were built with the forward method. Finally, all of the parts were assembled in CATIA with assembly design module and then we received the whole 3D digital model.2. The dynamical simulation model based on ADAMS software for the Sunroof motion mechanism is built up with the 3D Data. And the research and analysis about the model are carried out. The simulation results show the motion mechanism of this sunroof has good consistent movement discipline during the opening and the closing process, which ensure that the window glass and the car roof still match with each other perfectly. Meanwhile we found that the velocity of driving soft shaft does not affect the driving force significantly. From the result we can get the die displacement of driving soft shaft assembly and the max. driving force etc. during the sunroof opening or closing case. These data can be used for choosing the Motor, driving soft shaft and so on.3. The simplified parameter simulation model for Sunroof motion mechanism is built up. And the model is validated by comparing the simulation data with the physical experimental data. Applied with the function Design Study of ADAMS the sensitivity of design variables to the sunroof rising height are carried out. Then the design variables with higher sensitivity to the sunroof rising height are divided into two groups and studied with the function DOE of ADAMS. Finally, an optimization calculation with the target function max of sunroof rising height and constraint driving force on driving soft shaft less than 25N were executed with the design variables obtain from the last step.In a word, in this paper a deep and systematic study of the sunroof motion mechanism has been carried out. And we have obtained some innovational achievements for the sunroof motion mechanism design theory and applying the modern design technique in Productions development. The study of design theory provides the theoretical foundation for sunroof motion mechanism design and improvement. And the theory has solved the key technical problem in sunroof motion mechanism design. The applied modern design techniques can shorten the development period, reduce the development cost, and enhance the independent development capacity of the sunroof enterprise. These design theory and method have already accepted and applied in the new sunroof product design by Shenghuabo Group Ltd. Co. The trial produce has already finished and they have signed a contract with a certain automotive manufacturer for a small batch of production. The Study in this paper can also be an example for the development of others automotive parts with high technology.