基于定位法线的工件自由度分析几何定理及应用

发布时间：2018-01-30 13:17

本文关键词： 机床夹具设计异面组合定位自由度分析定位法线几何定理　出处：《机械工程学报》2017年09期 　论文类型：期刊论文

【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。
[Abstract]:When the workpiece is located in the cross-plane combination, the positioning points are often distributed on the non-orthogonal heterotope, and the traditional positioning principle will often misjudge the degree of freedom of the workpiece in the fixture, which leads to the failure of the fixture design. The normal line of the workpiece at the fixture location point is named as the location normal line, and a set of geometric theorems for judging the degree of freedom of the workpiece are derived according to the number of the locating normal lines and their geometric relations. The rule of normal distribution is given, which makes the judgment method of degree of freedom of workpiece more rigorous, simple and intuitionistic. At the same time, it can effectively avoid the over-positioning of workpiece. Give some difficult examples, judge the degree of freedom of workpiece by geometric theorem, and give the solution to the unreasonable location. It is proved that the geometric theorem can quickly and accurately judge the degree of freedom of the workpiece in the complex position state, and the geometric theorem of the workpiece localization develops and perfects the localization theory of the workpiece. It is helpful to judge the degree of freedom of workpiece in CAD.
【作者单位】：太原科技大学教育部重型机械工程研究中心;
【基金】：国家自然科学基金资助项目(51575373,51175360)
【分类号】：TG75;TH122
【正文快照】： 0前言*工件在夹具中自由度判断的正确与否直接关系到机床夹具设计的成败,无疑是夹具设计中最基础且最重要的任务,对此国内外学者进行了相关的研究。吴玉光[1]将工件定位基准的约束自由度定义为线平移、线转动、面平移和面转动四种类型,建立了从工序要求中自动提取约束自由度信

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