GB1463778A - Electrical machines - Google Patents

Abstract

1463778 Electrical machines ROBERT BOSCH GmbH 20 May 1975 [14 Aug 1974] 21408/75 Heading H2A An electrical machine has an iron magnetic flux return ring, field magnets secured in position on an inner wall of the ring by holding members, and a brush support which abuts the flux return ring, the holding members each being moulded on to the brush support in one piece. In the motor arrangement shown, a pair of annular permanent magnets 15 are secured against an inner wall 14 of a flux return ring 10 by a pair of bifurcated members 19 (only one illustrated in Fig. 2) projecting axially from, and moulded on to, a brush support 17 of flexible synthetic material, the end parts 23 of each member 19 being forced apart by a spring 24 to wedge tightly against the magnets 15. The support 17 carries two brush holders 18 (only one in Fig. 2), and has slotted guides 27 which are pushed on to the limbs 13 of a U-shaped bearing bracket 12 which is fixed to the ring 10. When the support 17 is mounted, stop shoulders 28 on the limbs 13 engage the support to prevent movement in one direction, and the front face 11 of the ring 10 is abutted by further projections 30 on the support 17 to prevent movement in the opposite direction. The spring for forcing the end parts of the projections 19 apart may be undulating or horse-shoe shaped and formed of wire (as in Figs. 5a, 5b, not shown), or it may be formed of a resilient band (Fig. 6a, not shown) and toothed (Fig. 6b, not shown).