GB1212313A - Method of manufacturing a stator for a miniature motor - Google Patents

Abstract

1,212,313. Making stators. PHILIPS ELEC- TRIC & ASSOCIATED INDUSTRIES Ltd. 9 April, 1969 [11 April, 1968; 3 May, 1968], No. 18225/69. Heading B3A. [Also in Division H2] A method of making a miniature electric motor stator comprises providing a body 4 of non-magnetizable material with a plurality of recesses, into each of which is fastened a polepiece 2 of magnetizable material which projects beyond the body 4, machining the stator body and polepieces to provide a central rotor accommodating cavity, positioning a stator winding 3 on each polepiece and fastening to the ends of the projecting portions of the polepieces 2 a shunt 5 or 9 of magnetizable material for closing the magnetic circuit. The stator body 4 is made of material having low electric conductivity, such as nickel-silver, and the polepieces, which are made of silicon iron, are soldered, welded or glued in position. The rotor 1, which may be of ferromagnetic material is machined either internally by a diamond drill, where it accommodates a stub shaft, or externally by a diamond grinding disc. After assembly in the silicon-iron shunt 5, end caps (8) are fitted at either end, the caps also serving to locate bearings (6) in which the rotor is journalled, Fig. 2 (not shown). In the embodiment shown in Fig. 5, the stub shaft 10 is journalled in a ball-bearing and may extend to between the windings. In a further embodiment, Fig. 6 (not shown), the stub shaft (10) is journalled in a jewelled bearing (13) and abuts a jewelled pivot stone (14), the space between the bearing and the stone forming an oil reservoir.