GB1118604A - Improvements in or relating to field magnet structures for dynamo-electric machines - Google Patents

Abstract

1,118,604. Core constructions. ROBERT BOSCH G.m.b.H. 23 Nov., 1965 [26 Nov., 1964], No. 49631/65. Heading H2A. In a dynamo electric machine field structure, the magnets 3, which are preferably formed from materials which are difficult to machine, such as sintered oxide materials, are secured to the machine frame 1 by an adhesive 4, such as epoxy resin, injected into the gap between the magnet and the machine frame through holes 5 in the frame 1. Slots are cut at each end of the frame to leave strips 7 (Fig. 2, not shown), which are inwardly deformed to prevent the adhesive from running out of the gaps. In a further arrangement (Fig. 3, not shown), a two-part frame 11, 12 is mounted together with the magnets 14 on a jig core 18 and adhesive is injected into the gaps 15 from two holes at the end of each frame half. The adhesive is then hardened by induction heating and means may be provided adjacent the polepieces for magnetizing them. Lugs (16) may be provided on the frame halves for mounting bearing covers and a brush carrier plate. In a still further arrangement (Fig. 5, not shown), four magnets (21) are glued to a cylindrical frame 20; the adhesive which is injected by nozzles (24) also flows to bores (23) in the frame, which when hard provide additional anchoring. The adhesive may contain powdered magnetizable material such as iron filings.