| With the development of Automobile industry and improving people,s living standard, the Automobile 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 consume. 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 luxury. Therefore, now the sunroof becomes more and more popular.In the past five years, the Chinese Automobile 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 by Webasto Company monopolized. 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 competing ability is very bad. They lie 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 motion 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. In this paper the basic concept, system structure, the key technology and applied engineering field of the reverse engineering are systematically presented. The ATOS no-contact three coordinate optical scanner from Germany was used to scan the sunroof glass assemble, deflector and drain system, which is 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. After systemic Introduction of multi-body dynamics theory, the mathematical Model of the sunroof motion mechanism is built up for the first time. The study on the design theory of the rail on the glass supporting bracket and quad of the soft driving shaft assembly is carried out. The concept of"contour line for same opening angle"is brought forward. There are transition lines for the rail design, which is part of the contour lines. When the quad moves on a transition line, the opening angle of sunroof will never change. The rail formed by connecting the endpoints of transition lines can realize the sunroof opening angle change between the predefined angles. This theory solves the technical difficult problem of sunroof rail design, which has puzzled sunroof enterprise.3. 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 that there are also transition segment for the rail design. The driving force on soft driving shaft is very small, when the quad runs on the transition segment. The forces on every joint are lager during the opening condition than during the closing condition. 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.4. The simplified parameter simulation model for Sunroof driving mechanism is built up. And the model is validated by comparing the simulation data with the model built up by 3D data. Applied with the function Design Study of ADAMS the sensitivity of design variables to the sunroof opening angle are carried out. Then the design variables with higher sensitivity to the sunroof opening angle are divided into two groups and studied with the function DOE of ADAMS. Finally, a optimization calculation with the target function max. sunroof opening angle and constraint driving force on driving soft shaft less than 25N are executed with the design variables obtain from the last step.5. By applying the software ANSYS Workbench the FEA model for sunroof motion mechanism was set up. And a EFA analysis about flexible dynamics was carried out to study the stress level during the sunroof opening process. The simulation results show that the safety coefficient of current design is very high and it can meet the requirement of strength.6. In order to shorten more the development period, a sunroof development platform should be built up. Based on the summary of the previous works, the feasibility of building up a sunroof development platform with the software CATIA, ADAMS and ANSYS workbench is discussed and the functions that this platform should provide are suggested. At last the development flow chart for sunroof development with modern design technology is presented.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 automobile manufacturer for a small batch of production. The Study in this paper can be an example for the development of others automobile parts with high technology. And this study will be meaningful for enhancing the technology standard of automobile parts industry.
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