针对X射线相位衬度CT(comPuted tomograPhy,计算机断层扫描)成像的高分辨率、高稳定性要求,设计了大型精密转台.转台采用焊接结构和密珠轴系支撑,具有质量轻、阻力小、回转精度高的特点.介绍了转台轴系的结构设计和工艺路线,根据成像视野区允许的运动误差对轴系精度指标进行了分解.通过静态分析、惯性释放分析和模态分析研究了转台的静、动态性能并验证了其结构刚度的合理性,结合精度分析对轴系关键部件的几何误差进行了分配,误差综合结果满足指标要求.最后,对转台样机的轴系精度进行了检测,结果表明各项指标满足相位衬度成像要求.焊接结构的轻量化设计和轴系精度分析方法对大型转台轴系的研发具有一定的借鉴意义.%A large-size precision turntable was designed for the requirement of high resolution and high stability of the X-ray phase contrast CT(computed tomography)imaging.The turntable a-dopted welding structure and dense ball bearing support,with the feature of light weight,low re-sistance and high rotary precision.T he turntable shafting's structure design and process route were introduced.The accuracy index of the shafting was decomposed according to the motion error allowed in the imaging field.The static and dynamic performance of the turntable was stud-ied by static analysis,inertial release analysis and modal analysis,w hich proved that the structure rigidity was reasonable.Combined with the precision analysis,the geometric error of important components of the shafting was distributed,and the synthesis error satisfied satisfied with the requirement of index.Finally,the shafting of the turntable prototype was tested.The results showed that the turntable met the requirements of phase contrast CT imaging.The design of lightweight welding structure and the method of shafting accuracy analysis have some reference for large-size turntable shafting development.
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