Abstract
Fixed Sunroof System (FSS), which consists of a large size heat-strengthened roof panel glass, locating components, encapsulation, etc., is replacing traditional metal roof panel on vehicle to achieve weight reduction as well as providing a broad vision above passengers. As a result of the roof panel glass surface area and curvature, FSS could not be self-fixed on vehicle bodyside outer by means of its locating components currently and a tooling fixture is needed when the fixed sunroof be assembled to vehicle. Meanwhile, varied status of the interferences between FSS and vehicle outer or inner sheet metal may introduce additional loading forces while assembling. That could involve perceived quality issues on its appearance. At the same time, safety performance of FSS also leads a critical role on replacing traditional metal roof panel. This paper is aimed to present a comprehensive design strategy for FSS to achieve self-fixed to vehicle sheet metal as well as robust and sufficient assembly process. For the part of self-location, the concepts are divided to two major directions: location pins’ layout and pins’ structure. A reasonable layout and a new-developed structure of the location clip are essential to make sure the operators could see the clips clearly when assembly, which also conducive to avoid over-positioning. In addition, the fixed sunroof cannot be a naked glass because of appearance reason and seal function requirement. The relationship between loading force and encapsulation’s structure, material and interference volume distributed on the FSS should be established with the purpose of optimizing assembly process and improving interference performance.
This study also develops into detail by experimental and finite element analysis method to figure out the contribution on loading force from encapsulation’s structure, material and interference volume. Moreover, the strength of the FSS can be taken depends on is manufacture process and the shape of the glass. The key elements in manufacture process and the feasibility of further optimization can be identified by means of theoretical in the formation of glass stress. The effect of the fixed sunroof on entire vehicle can be estimated by FE analysis. This paper combines the traditional process with these new-optimized elements, which creates a new manufacture process to achieve a heat-strengthened roof panel glass with lager surface and high rigidity taking the reference of the production process in windshield and backlite. A detection method on glass strength and stiffness can also be figured out during the study in this new manufacture process.
