| 摘要 |
PURPOSE:To prevent any deterioration in accuracy of a moving stage due to the generation of heat, by fitting hollow pipes of high thermal conductivity in the rotor of a linear step motor in a vacuum chamber, and supplying a cooling medium therethrough from the outside of the chamber. CONSTITUTION:A cooling gas or the like pumped in from an inlet 26 is branched into pipings 24, 25 in a block 22 and arranged to flow into hollow pipes 14, 15. The heat generated in exciting coils 11 and conducted to a stator 10 and a rotor 5 is forcedly removed by the cooling medium through the walls of the hollow pipes 14, 15. The cooling medium is collected in a block 23 and discharged from an outlet 27. By this constitution, it is possible to suppress the thermal expansion of the stator and that of a mounting stage 1 by the heat conducted thereto from the rotor through a connecting part. Accordingly, a high-speed moving stage is realized which has a high responsiveness while maintaing a high accuracy by the drive of the step motor in a vacuum. |
