| 摘要 |
1. Device for the automatic opening and closing of sliding doors, comprising a single-phase asynchronous alternating current (a. c.) motor (6, 7, 8) having rotating field windings, which acts via a transmission on a traction means, driven in the opening and closing directions, to which are attached one or more carriages (2, 3) each of which rolls along within the inner space of a carrying section (1) extending in the longitudinal direction of the traction means, a door panel (42, 43) being fastened to each carriage, characterised in that the a. c. motor (6, 7, 8) has an extremely short structural length because it is constructed as a single-phase asynchronous a. c. motor comprising a ring winding (8) having a rotating field characteristic and appropriately devised so that in the event of a stoppage of the motor caused by a high opposing torque the back induction in the rotor (9) is great and the short-circuit current caused thereby is small. |
