| 摘要 |
1,234,744. Making magnetic rings; jointing. SIEMENS A.G. 30 Jan., 1970 [30 Jan., 1969], No. 4716/70. Headings B3A and B3V. [Also in Division H2] A method of making short-circuiting rings for the permanent magnet of an electric motor comprises forming a split ring by rolling from a metal strip, tensioning the ring to a desired diameter and maintaining that diameter by securing a tube to the inside or the outside surface of the ring by a high-velocity forming method. The split ring, which is rolled from iron, is tensioned to the required diameter by means of a mandrel and an aluminium tube is pushed on to the ring. The assembly is then placed within an air-core coil and eddy currents are induced in the tube by discharging a capacitor bank through the coil. The electro-magnetic interaction compresses the aluminium tube so that a part is forced into the split of the ring, thereby maintaining the desired internal diameter after removal of the mandrel. An accurate external diameter is obtained by inserting the split ring into a bore and expanding an aluminium tube against the inner surface of the ring and into the split. The forming may be performed by the hydrospark method. |
