Assembly position precision analysis method considering geometric tolerance and deformation influence

Abstract

The invention discloses an assembly position precision analysis method considering geometric tolerance and deformation influence. The method comprises the following steps: determining a closed ring of a to-be-analyzed part, and constructing an assembly dimension chain model according to an assembly relationship; according to the assembly dimension chain model, setting the dimension tolerance and the geometric tolerance of each part forming ring of the to-be-analyzed part; simulating part deformation under the action of gravity by a finite element method, and extracting discrete node coordinate values of key characteristics of the deformed part; fitting discrete node coordinate values by adopting a least square method, and obtaining the deformation amount of a ring formed by the deformed part; according to the deformation of the deformed part forming ring, modifying the basic size value of the part forming ring; simulating the size distribution and tolerance range of the closed ring by adopting a Monte Carlo random sampling method; and detecting whether the closed ring meets the crankshaft assembly position precision requirement or not. According to the method, whether the tolerance of each currently arranged part forming ring can meet the assembly position precision can be analyzed.

Description

technical field [0001] The invention belongs to the field of mechanical assembly precision design, in particular to an analysis method of assembly position precision considering the influence of geometric tolerance and deformation. Background technique [0002] Assembly accuracy is an extremely important quality characteristic of mechanical products. Good working performance of mechanical products must be guaranteed by qualified assembly accuracy. Especially for high-speed precision mechanical equipment, small assembly position deviations will bring eccentric force and vibration of the whole machine. , Abnormal noise and other problems, and even cause fatigue fracture of some parts. In the actual mechanical product design and manufacturing process, designers mainly rely on past design experience and design manuals to design the accuracy of parts. After actual parts processing and assembly, they will know whether the designed parts accuracy can meet the assembly accuracy requ...

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Problems solved by technology

The Chinese patent "A UG-Based Plane Dimension Chain Calculation Method" (Application No.: 201611036791.9) proposes a UG-based planar dimension chain calculation method, which utilizes the planar dimension chain diagram and the dimension-driven function of the UG sketch to perform the calculation of each component ring. The increase and decrease loop analysis uses the extreme value method to calculate the tolerance range of the closed loop; the component loop of the invention only considers the dimensional tolerance, and does not consider the influence of geometric tolerance and part deformation on the closed loop, which makes the analysis result unreliable. The value method calculates the tolerance range of the closed ring, does not simulate the size distribution of the closed ring according to the distribution law of the constituent rings, and does not conform to the actual processing conditions of the parts

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