根据国内外空间焊接技术的研究状况,提出了我国空间电子束焊枪用等径三圆筒单透镜为主透镜的电聚焦系统设计方案和计算机辅助设计方法,利用计算机编程完成了聚焦系统的参数概算并取得了满意的结果。研究结果表明:电子束电流散焦小,在偏转磁场中束截面较小,工件上的束斑半径最小可达0.65615mm,可满足空间焊接和切割的需要,并证实了空间电聚焦系统的计算和设计方法是正确的。 According to the research status of welding technology in space at home and abroad, the design scheme and computer aided design method of focusing system for the electron beam welding torch in China are proposed. The parameters of the focusing system are calculated by computer programming And achieved satisfactory results. The results show that the beam current defocusing is small, the beam cross section is small in the deflection magnetic field, and the beam spot radius on the workpiece is as small as 0.65615mm, which can meet the need of space welding and cutting. And the calculation of space electrofocusing system is confirmed And the design method is correct.