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一、概述本文所讨论的问题,在П型精密零件双臂上的小孔不同轴度误差测量中,是经常迂到的。这种П型结构(图1)常用来安装细长轴的轴尖或直接以其孔来和轴颈配合。因此除了对两臂上的孔径提出较高要求外,对其不同轴度也提出了相应的要求,否则会使新安装的轴产生倾斜甚至卡紧。但是,由于结构上的限制,这种零件一般尺寸较小,尤其是双臂的刚度很差,极易产生变形。本文重点讨论的就是当小孔直径D≤3~4毫米、而跨距L>>D的情况。根据双臂上两孔轴心线在空间的位置关系,大抵有下表所列的三种情况: 通常,在仔细而合理的安装夹紧情况下,保证定位基准、定位面不变时,表中所列第Ⅰ种误差情况往往是可以避免或变得很小。第Ⅱ
First, an overview of the issues discussed in this article, П-type precision parts on the small hole axis error measurement is often roundabout. This Π type structure (Figure 1) is often used to install the shaft tip of an elongated shaft or directly with its hole and journal fit. Therefore, in addition to the requirements of the two arms on the aperture higher requirements, its different axis also made the corresponding requirements, otherwise it will tilt the shaft or new installation even clamped. However, due to structural limitations, such parts are generally smaller in size and, in particular, have poor stiffness of the arms and can easily deform. This article focuses on the case when the hole diameter D ≤ 3 ~ 4 mm, while the span L >> D situation. According to the position of the two arms in the space between the axes of the two holes, there are probably three cases listed in the table below: Normally, with careful and reasonable installation and clamping, when the positioning datum and the positioning surface are not changed, The first type of error listed in the often avoidable or become very small. Ⅱ