Research On The Application Of Size And Tolerance Analysis Based On CETOL

Tolerance analysis is an important means to check the rationality of product design in the stage of product development.It has been used more and more widely in automotive,aerospace,weapons and other industries.The correct tolerance analysis can optimize the size and tolerance?GD&T?scheme.Predicting product assemblability ahead of time can reduce the cost and increase the enterprise benefit while ensuring the geometric function requirement of the product,so the tolerance analysis is very important in the process of product design and development.With the development of computer aided tolerance design and 3D visualization technology,the traditional manual dimension and tolerance analysis is gradually replaced by computer aided tolerance analysis.The tolerance analysis software with good practicability and powerful function appeared.This paper has carried out some applied research work supported by the National Natural Science Foundation of China "the Theory and method of functional tolerance Design based on axiomatic Design?51475219?" and the key Project of Graduate Innovation Program?SJCX17₀745?of Jiangsu Institute of Technology.In this paper,the title of the master thesis "Application Research of Dimension and tolerance Analysis based on CETOL" is presented.The main research contents are as follows:1)The research status of computer aided tolerance design?CAT?at home and abroad is summarized,and several mature commercial CAT software are introduced.The application software related to this paper and the main research problems in this paper are introduced.2)Some mathematical methods for tolerance analysis are introduced.The concrete algorithm of CETOL software is introduced.3)The problem of tolerance compensation and reference offset is discussed by analyzing and studying the application of maximum entity requirement to measured and benchmark elements.Based on the function and assembly requirements of parts,the key features are determined and the key ring containing key features is analyzed by CETOL software.The form of simulated tolerance compensation and the variation of tolerance zone.4)Taking the dimension and tolerance design of the end cover of oil pump as an example,based on the The function and precision of the parts require the determination of key features and key rings,the establishment of different types of dimension chains,and thecomparative analysis of the merits and demerits of each type of dimension chains.This paper discusses the effect of tolerance distribution and use tolerance principle?such as maximum entity requirement?on the qualified rate and cost of parts.5)Taking Chebyshev walking machine as an example,the construction and simplification of dimension chain of connecting rod mechanism with operation requirements are discussed.In order to ensure the running track of the mechanism as the design requirement,the Solidworks motion simulation software is used to capture the kinematic trajectory of the linkage mechanism,and the path of the linkage mechanism is filtered by Matlab software,and the target point set is selected,and the selected target points are analyzed.The instantaneous state,which has the greatest influence on the kinematic trajectory of the mechanism,is used to construct the dimension chain according to the instantaneous state,and the tolerance analysis is carried out.6)taking the derived dimension chain as the research object,the particularity of this kind of dimension chain is analyzed.Taking the high-speed bearing protection device as an example,the dimension chain of assembly layer and parts layer is established,and the optimization scheme of assembly layer dimension chain is compared and analyzed.When the assembly layer and the part layer are the ring,the adjustment scheme of the ring which is selected as the adjusting size according to the contribution degree is analyzed and verified by an example.