Study on an Ultra-precisely Joining Method for Optical Lenses using a Shrink Fitter

去年，我们用有限元法得到了收缩装配器的最佳尺寸和尺寸。在分析中，使用了每种类型的透镜的目录数据的物理性质。POM用作收缩装配材料。此外，还建立了考虑透镜与壳体配合面形状误差的数值模拟技术。过盈配合是一种过盈配合，要求配合面的尺寸精度高。结果表明，拟合曲面的形状误差很小.因此，在数值模拟中，形状误差对接触压力分布几乎没有影响。去年开始的收缩接头用高分子材料的蠕变试验在三种温度条件下继续进行。使用了四种不同的聚合物材料。经过500小时后，蠕变位移保持不变，几乎没有观察到进一步的蠕变位移。本年度还研究了更简单的光学透镜接合方法。在过盈配合中，要求有较高的尺寸精度。因此，热收缩装配工和壳体的加工成本增加。如果可以增加配合表面所需的尺寸公差，则加工成本就会降低。然后，转动收缩装配器的周边，使得收缩装配器的装配表面的接触面积可以减小。作为第二种方法，在将光学透镜和收缩装配器插入壳体中之后，沿一个方向切割壳体，并通过带紧固。这两种方法可以放松收缩装配的尺寸公差。此外，还证实了通过在数值模拟中积极地将形状误差引入到收缩装配器中，也可以放宽收缩装配器的尺寸公差。

Optimum Shapes and dimensions of the shrink fitter were obtained using finite element method last year. In the analysis, the physical properties of catalog data for every type of the lens were used. POM was used as the shrink fitter material. In addition, the numerical simulation technique which could consider form error of fitting surfaces of lenses and the housing was developed. It is required that the dimensional accuracy of fitting surface is high, because the shrink fitter method is a shrinkage fit. As a result, the form error of fitting surface is little. Therefore, in the numerical simulation, there was almost no effect of the form error on the contact pressure distribution.The creep tests of polymer materials for shrink fitter, which were started last year, were continued under three kinds of temperature conditions. Four different polymer materials were used. It became that the creep displacement was constant after 500 hours, and further creep displacement was hardly observed.Simpler method of joining the optical lenses was also examined in this fiscal year. The high dimensional accuracy is required in the shrinkage fit. Therefore, the processing cost of the shrink fitter and the housing increases. The processing cost becomes low, if the dimensional tolerance necessary for fitting surfaces can be increased. Then, the periphery of the shrink fitter was turned so that the contact area of fitting surface of the shrink fitter may decrease. As the second method, the housing was cut in one direction, and tightened by the band, after the optical lens and the shrink fitter were inserted in the housing. Those two methods could loosen the dimensional tolerance of the shrink fitter. In addition, it was confirmed that dimensional tolerance of the shrink fitter could be also loosened by positively introducing the form error to the shrink fitter in the numerical simulation.