| Automotive glass is one of the most important parts of the car,whose installation quality has great influence on the vehicle performance.Meanwhile,positioning pin appears particularly significant as the fixed device of automotive glass.At present,the assembly of positioning pin is mostly completed by rigid fixture in the domestic enterprise,which only suits for a specific model of the automotive glass.With the increasingly fierce competition in the automotive market and the increasing number of automotive glass specifications,rigid fixture has been unable to meet the current development needs.In order to solve this problem,this paper developed a flexible fixture for the assembly of positioning pins,which not only completes the assembly of positioning pins concerning various types of automotive glass,but also improve the positioning accuracy of the positioning pin.The main contents are as follows.Firstly,the overall design and detailed structure design of the flexible fixture were completed.Then,the key mechanism of flexible fixture was designed and modeled through SolidWorks software,which mainly contained automatic centering clamping mechanism,supporting vacuum chuck mechanism,orientation institutions along y axis,clamping mechanism along y axis and a positioning pin assembly mechanism.Afterwards,aiming to check the strength and stiffness,the statics analysis was carried out by Workbench software.Meanwhile,develop a new type of vacuum chuck mechanism,which integrated the positioning support and adsorptive fixation,improving the reliability and efficiency of the fixture.Secondly,the design of the key clamping device in the flexible fixture were optimized.Based on the kinematics analysis,the optimization mathematical model of automatic centering and clamping mechanism was established,which uses ADAMS software to optimize analysis and solution.Whose results would be applied to optimize the structure size of the mechanism to improve the dynamic performance.Thirdly,the layout of the positioning and clamping elements in the flexible fixture was optimized.Then the flexible fixture layout optimization based on genetic algorithm and finite element method,was set up to get the optimization layout,in which the deformation of the automotive glass is less.Afterwards,contrasting the stress and deformation of the optimal glass and before by Workbench.The optimizedfixture layout will be used to guide the assembly and debugging of flexible fixture.Finally,the assembly experiment of positioning pin on the windshield of the car is conducted,using the corresponding device to detect installation accuracy.And the results show that the flexible fixture can well meet the actual engineering requirements.The flexible fixture designed in the paper not only meet the actual production needs of enterprises,but also have some reference value for other thin-walled parts flexible fixture. |
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