• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2018, Vol. 54 ›› Issue (11): 29-38.doi: 10.3901/JME.2018.11.029

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Uncertainty Analysis of Assembly Error of Planar Single-loop Mechanisms Based on the Rotatability Laws of Linkages

ZHAO Qiangqiang1,2, GUO Junkang1,2, HONG Jun1,2   

  1. 1. Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049;
    2. State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710054
  • Received:2017-06-18 Revised:2017-12-14 Online:2018-06-05 Published:2018-06-05

Abstract: The link deviation, assembly constraint error and joint clearance are the major error sources, which affect the assembly accuracy of planar single-closed-loop mechanisms. However, the randomness of joint clearance results in the accuracy uncertainty of the planar single-closed-loop mechanism. In order to predict the assembly accuracy and obtain the error bound, two assembly components, single-fixed link and two-connected link, are proposed and their error models are established by analyzing the assembly property of a planar four-bar single-loop mechanism. And accordingly, the error modeling of assembly error of the single-loop mechanism without considering joint clearance is firstly completed. Then the uncertainty analysis model of assembly error of the planar single-loop mechanism is built by introducing the rotatability law of the linkage, in which the joint clearance is regarded as a ‘short link’. In addition, the method of calculating the bound of assembly error is given. At last, the feasibility and utility of the method proposed above are verified by a numerical example of the planar five-bar single-loop mechanism.

Key words: assembly component, assembly deviation, planar single-loop mechanism, rotatability laws

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