| 摘要 |
PURPOSE:To define a gap with parallel sides precisely, by bumping each other two electromagnets each consisting of a main cylindrical yoke with a cross sectional convex shape and a coil, with a spacer made of magnetic alloy having a low thermal expansion coefficient put between two return ring yokes to define the gap. CONSTITUTION:Coils 4,4' are inserted and fixed in spaces defined between return yokes 5, 5' and the projection side walls of main yokes 2, 2' respectively. The upper and lower electromagnets A, B so constructed having the same configuration are bumped with a gap 1 put between the projections of the main yokes. Within the gap defined between the bumpering sections of the return yokes, a spacer, for example made of 35% Ni-Fe alloy, is put, and the upper and lower electromagnets are fastened to finish an electromagnet apparatus. Since this electromagnet apparatus has the upper electromagnet A and lower electromagnet B arrayed symmetrically, paralleling the magnetic poles can be easily attained. Moreover, when the ring spacer 6 having the same height as that of the gap 1 to be defined between the main yokes is put between the upper and lower return yokes with being contacted to them, the magnet gap between the upper and lower yokes can be defined precisely. |
