• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2017, Vol. 53 ›› Issue (9): 157-163.doi: 10.3901/JME.2017.09.157

• • 上一篇    下一篇

基于定位法线的工件自由度分析几何定理及应用*

王晓慧, 吴冬祖, 兰国生, 王友利   

  1. 太原科技大学教育部重型机械工程研究中心 太原 030024
  • 出版日期:2017-05-05 发布日期:2017-05-05
  • 作者简介:

    王晓慧,男,1959年出生,教授。主要研究方向为尺寸工程,机械精度设计理论及应用,计算机辅助夹具设计。

    E-mail:houmawxh@sina.com

  • 基金资助:
    * 国家自然科学基金资助项目(51575373,51175360); 20161011收到初稿,20161219收到修改稿;

The Geometry Theorem and Application of Degree of Freedom Analysis of Workpiece Based on Location Normal

WANG Xiaohui, WU Dongzu, LAN Guosheng, WANG Youli   

  1. Heavy Machinery Engineering Research Center of Education Ministry, Taiyuan University of Science and Technology, Taiyuan 030024
  • Online:2017-05-05 Published:2017-05-05

摘要:

工件在异面组合定位时,各定位点常分布在非正交的异面上,用传统的定位原理时常会误判工件在夹具中的自由度而导致夹具设计失败。针对这一问题,将工件在夹具定位点处的法线命名为定位法线,根据定位法线的数量及其几何关系推导出一组判断工件自由度的几何定理,并对工件过定位时所对应的法线分布情况给出判断准则,使工件自由度的判断方法更加严谨、简单、直观,同时可有效避免工件产生过定位。例举几个疑难实例,用几何定理判断工件的自由度,并对不合理的定位给出解决方案,证明了几何定理可以快捷准确地判断工件在复杂定位状态的自由度。工件定位的几何定理发展与完善了工件的定位理论,有利于计算机辅助夹具设计中对工件自由度的正确判断。

关键词: 定位法线, 几何定理, 异面组合定位, 自由度分析, 机床夹具设计

Abstract:

:When workpiece is in combined location in non-coplanar planes, every location point is usually distributed at non-orthogonal and non-coplanar planes. The degree of freedom of workpice in fixtures is sometimes misjudged by using traditional positioning principle, which always leads to failure of fixture design. For this problem, the normal at location point where workpiece lies in fixtures is nominated as location normal. A set of geometry theorems that can judge the location state of workpiece are derived according to the amount of location normal and the geometry relationship between them. Some judging principles are given out for normal distribution corresponded with over-positioning of workpiece. The geometry theorem makes the judging method of degree of freedom more precise, simpler and more intuitive and over-positioning of workpiece can be avoided effectively at the same time. Several complicated examples are enumerated. The degree of freedom of workpiece can be judged and the solution can be given out for the unreasonable location by the means of using geometry theorem, which prove that the degree of freedom of workpiece in complicated location state can be judged quickly and accurately. The geometry theorem of workpiece location has developed and completed the location theory of workpiece and is good for correct judgment to the degree of freedom of workpiece in computer aided fixture design.

Key words: combined location in non-coplanar planes, degree of freedom analysis, geometry theorem, location normal, machine tool fixture design