| 摘要 |
1,212,775. Electric motors. PAPST-MOTOREN KG. 25 Oct., 1968 [27 Oct., 1967], No. 50736/68. Heading H2A. A housing of a small motor, e.g. for a typewriter or tape recorder, consists of at least one metal layer and at least one layer of soundproofing material e.g. butyl rubber or coldflowing polyisobutylene said housing forming at least a part of the working magnetic circuit. Fig. 1 shows a D.C. motor having a permanent magnet field 7 attached to a casing consisting of a bell-shaped portion 5 and an end cover 6 each comprising two metal layers 13, 14 with an interposed layer 15 of soundproofing material. The casing part 5 may be made by deepdrawing and one of the metal layers may be of ferromagnetic material and the other of non- magnetic material, such as aluminium. The casing may be tubular in form, Fig. 3, and formed by bending or rolling a prefabricated laminate, the meeting edges 213a, 214a of the inner and outer metal layers being off-set. In Fig. 7, a bell-shaped laminated casing 705 forms an external rotor and co-operates with a fixed, laminated end cover 706. The inner metal layer of such a rotor may carry a barium ferrite sleeve (34) so as to form a hysteresis motor Fig. 8 (not shown). |
