Study On Dimension Chain Optimized Design Of Dimple Lock

Design determines the quality of the product.The tolerance design is the core of product structure design.In the tolerance design,the most important is dimensional chain analysis and calculation.Through a case study of the design and optimization of the dimension chain of a typical lock product,the importance of the dimension chain and how to control and improve the quality of the product design were described.Taking the dimple lock item X as example,by using the theory of dimension chain.The paper was organized as the following three steps:analysis,optimization and validation.First of all,the main factors of unsmooth pulling and plugging of the key was identified the center offset of the pin hole and the gap between the edge of pins and the hollow pin hole of lock shell.And the main factors of high mutual opening rate was identified the radial gap of the lock shell and lock core,the radial gap of pins and the core after inserting the key and the chamfer of hollow pins,and reasons result in the problems above were analyzed and the dimension chain were recalculated by extreme value method.The unsmooth pulling and plugging of the key caused by the max center offset of pin hole is 0.32mm,which is much larger than the min gap 0.0.1mm between the edge of pins and the hollow pin hole of lock shell.The high mutual opening rate result in the max radial gap is 0.675mm between the edge of hollow pins and the pins hole of core,which is greater than the current differential 0.4mm.Then,the improvable influencing factors were discussed,and an optimized design scheme was reached.It is concluded that improving the unsmooth pulling and plugging of the key by adjusting the size and tolerance,the center offset of pin hole is symmetrically distributed,and increasing the chamer of pins and increase gap between the edge of pins and the edge of hollow pins hole.The design for improving the mutual opening rate is to reduce the cumulative dimensional tolearance of affecting factors by adjust the dimensions and tolerance of internal diameter of lock shell,the outer diameter of core and the length of pins,and to increase the differential to 0.5mm.The feasibility of the scheme was theoretically verified by extreme value method.And on this basis,create the analysis model.Finally,the feasibility of the optimized scheme was validated by pilot run.The study proved the important application value of dimension chain tolerance accumulative analysis,which provides theoretical analysis basis and method for the design of dimple lock structure.The research of this paper shows that using dimension chain tolerance accumulative analysis in the initial stage of dimple lock structure design could improve the success rate of assembly and product quality,shorten the delivery time and reduce the production cost,and promote the benefit growth of the enterprise.