Tolerance technology-oriented assembly geometric element error transfer diagram representation and construction method

Abstract

The invention discloses a tolerance technology-oriented assembly geometric element error transfer diagram representation and construction method, which comprises the following steps: (1) obtaining an assembly component structure tree and an assembly cooperating relationship set in an assembly CAD model; (2) automatically constructing a geometric element error transfer diagram GAsm=(V,E) between assembly parts according to the order from a target part to a rack part; (3) obtaining three-dimensional CAD models and tolerance marking information of the parts in the assembly; (4) converting the obtained tolerance marking information into data in a benchmark-target correlation form; (5) obtaining internal geometric error transfer diagrams of the parts from the geometric element error transfer diagram between the assembly parts to construct required assembly positioning element information; and (6) automatically constructing the internal geometric element error transfer diagram GPart=( V', E') of the part belonging to a corresponding vertex of the geometric error transfer diagram between the assembly parts by the assembly positioning element information and benchmark-target correlation data in the parts.

Description

technical field [0001] The invention belongs to the technical field of computer-aided tolerance design (CAT), and in particular relates to a method for generating error transfer path diagrams in mechanical product tolerance automatic analysis and design software. Background technique [0002] The purpose of assembly tolerance analysis is to determine the range of position variation of the target elements in the machine and the sensitivity and contribution of the geometric error of the associated elements on each part of the machine to the position variation of the target elements. Determining this range of variation needs to involve all associated parts and associated elements on the machine assembly model, so it is necessary to find out all associated parts and associated elements on the machine, and determine the path of action of the geometric error of each associated element on the part that affects the position of the target element. Analyze the error action mode betwee...

AI Technical Summary

Problems solved by technology

These problems include: 1) Only the chain size can be described, or the spatial size relationship can be decomposed into three coordinate directions for separate calculation

3) The assembly relationship representation model is not suitable for expressing the error transfer relationship, resulting in a complex generation algorithm for the size transfer relationship, which is not conducive to direct use in assembly tolerance analysis

4) All kinds of 3D design analysis software almost adopt the form of assembly structure tree for the assembly model, while the assembly relationship tree can only represent the affiliation relationship of parts, especially when the assembly parts are co-located by multiple positioning parts, the tree structure can't describe it, wait

[0004] Due to the complexity of computer-aided tolerance technology, the research on tolerance design technology, especially three-dimensional tolerance design technology, is far behind the research on CAD, CAPP and CAM, making it difficult to integrate with current CAD / CAPP / CAM

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