GB769162A - Magnetic pole structure - Google Patents

Abstract

769,162. Electromagnetic brakes. WARNER ELECTRIC BRAKE & CLUTCH CO. May 12, 1955 [Jan. 21, 1955], No. 13755/55. Class 103 (1). [Also in Groups XXIV and XXXV] In an electromagnetically actuated friction clutch or brake, the winding is mounted on an annular stationary core 12 located between but spaced from two concentric rotating rings 13, 14 of magnetic material which are rigidly connected together by channel shaped spacers 17 of high reluctance material. When the coil 11 is energized the rings 13, 14 attract an armature 19 toward surfaces 20 to effect the desired clutching or braking action. To avoid slip between the rings and the armature, a material 21 having high co-efficient of friction is inserted in an annular recess 22 between axial extensions of the rings. The two rings 13, 14 are made by cutting away metal from an annular shell 26 by first forming an annular groove 30 into which the connecting spacers 17 are inserted and welded at their flanges 34 to the bevelled edges 32 of the groove 30. Then the remaining metal of the shell 26 near the groove 30 is removed so as to leave two rings 13a, 14a joined solely by the spacers 17 as in Fig. 5. When the spacers are required to have greater rigidity, they may be increased in circumferential length or formed into one complete annulus. In such a modified form, the shell 261 is formed of a ring of J-shaped section as in Fig. 9, which also shows the spacer 17<SP>1</SP> prior to its insertion into the groove 38. The spacer mechanical stability may be increased by filling the spacer with a compound 40 which will set after moulding. In both embodiments employing spacers 17 or 17<SP>1</SP>, the two concentric magnetic rings 13, 14 can expand or contract with temperature variation without subjecting the welds between them and the spacers to a shearing stress.