Improvements in or relating to Electric Motors

摘要

1,165,186. Clutch/brake units; disc brakes. INDIVE G.m.b.H. 1 Dec., 1966, No. 53917/66. Headings F2E and F2L. [Also in Division H2] The invention provides a squirrel-cage motor driving, e.g., a laundry spin dryer or a centrifuge on a vertical axis; the motor is associated with a mechanical brake; and the induced rotor field holds up, during running, a magnetic axially-movable member to prevent the brake being applied. As shown, the mechanism provides, in effect, three clutches between, on the one hand, the rotor and its shaft and, on the other hand, the brake. The parts are shown in the positions they occupy while the motor is running. An end ring 12 of the squirrel cage is accommodated in a U-section yoke M of magnetic material which has apertures at 15, opposite the rotor grooves, through which the bars 13 extend, the cage being a one-piece aluminium casting. The induced field is effective, even during running at maximum speed, to retain an axiallymovable annular body 21, of magnetic material, in contact with the yoke M against the force of a helical compression spring 22 which is anchored to the rotor 11 and may be anchored to the body 21. Other clutch parts comprise a sleeve 41 with conical top 411, a helical spring 44 anchored at its top to sleeve 41, a coupling member 43 loose on the rotor shaft 10 and having a flange 431-these parts being stationary while the motor is running-and finally another coupling member 42 keyed to the rotor shaft 10 and spaced from spring 44. The brake is constituted by the rotatable flange 431, lying between friction surfaces located on a stationary disc 31 adjustably loaded by springs 33 and on the end of the motor casing. In operation, when the motor current is switched off, the body 21, which is not connected with shaft 10, is pushed downwards by the spring 22 and, still rotating, it makes contact with sleeve 41. The now-rotating sleeve 41 winds the spring 44 so that it frictionally couples the members 42, 43, so that member 43 rotates. Member 43 is braked by the friction surfaces acting on its flange 431 whereby, through spring 44 and member 42, the shaft 10 and rotor 11 are brought to rest. (Thereafter, the resilience of springs 44 and 22 permits limited rotation, in both directions of the dryer or centrifuge.)