GB272299A - Improvements in and relating to electromagnetic brakes and couplings for transmitting mechanical power - Google Patents

Abstract

272,299. British Thomson-Houston Co., Ltd., and Young, A. P. March 12, 1926. Electric and magnetic. - An electromagnetic clutch or brake device without frictional contact between its members consists of a permanent magnet ring with internal or external poles on one shaft co-operating with a squirrel cage rotor on the other shaft, means being optionally provided for axial adjustment of the rotor relatively to the magnet to control the transmitted torque. Fig. 1 shows a clutch applicable to a motor vehicle drive in which the driving shaft 2 drives a non-magnetic casing 1 which carries a number of spaced permanent magnets 4 co-operating with a squirrel cage rotor 6 on the driven shaft 5. The casing 1 runs on a ball bearing 10 on the fixed outer casing 7 and supports the bearing 11 for the shaft 5. By means of levers operated through a bore in the shaft 5, or by other means, the rotor may be moved axially with regard to the magnets to transmit a desired torque and a laminated magnetic armature 12 may be provided to move with the rotor and form a flux shunt. When the clutch transmits large powers, it may be cooled by air which is passed through or over it, or it may be enclosed in a fluid-tight casing immersed in a cooling medium. Alternatively, the conductors may be tubes through which the cooling medium flows, or if the squirrel cage surround the magnets, some of its annular core laminµ may extend beyond the others to form cooling fins. The magnet poles may be on the inner or outer surface of the ring. For use as a brake, one member, e.g. the field member, is locked and the braking is controlled by moving the rotor into or out of the field. Specifications 26324/08 and 28130/08 are referred to.