| 摘要 |
PURPOSE:To perform clean transfer without generating dust, by allowing a travelling car for transferring a cassette containing semiconductor wafers to float above a track so that the travelling car can run in a state out of contact with the floor. CONSTITUTION:Since when the travelling car body 7 is put on a track body 3, floating permanent magnets 2a, 2b of the track body 3 and floating permanent magnets 9a-9d are arranged such that their poles of the same polarity are faced to each other, the travelling car body 7 floats above the track body 3 due to the repulsion between the magnets. To drive the travelling car body 7, the electric current to an electromagnet 1 above which a permanent magnet 10 is positioned is cut, and one of electromagnets 1 that are on both sides of the permanent magnet 10, that is, one positioned on the side to which the travelling car body 7 is required to be moved, is magnetized to attract the permanent magnet 10, while the other is magnetized to repulse the permanent magnet 10, so that the travelling car body 7 is moved toward the former electromagnet 1. Thus by successively changing the direction of porality of the electromagnets 1, the travelling car body 7 is moved continuously. |
