Method of manufacturing retention structure for electric motor rotor magnets
First Claim
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1. A method for manufacturing a shaft mounted rotor assembly for an electric motor comprising:
- mounting a plurality of permanent magnets in angularly related adjacent positions on a cylindrical bored rotor core having inner and outer peripheral surfaces to substantially surround said outer peripheral surface of said core in a core/magnets assembly;
supporting said cylindrical core/magnets assembly in a preselected position by support means inserted in said core to extended along said inner peripheral surface of said core;
encasing said core/magnets assembly in an opposed pair of cooperative mold members contoured to matingly surround the outer peripheral surfaces of said permanent magnets in preselected spaced relation therewith providing a space therebetween; and
injecting a plastic molding material into said space between said molds and the outer peripheral surfaces of said magnets to encapsulate said magnets in a unified, integral plastic molded sleeve.
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Abstract
An improved shaft mounted rotor assembly for an electric motor and method of manufacturing the same wherein a plurality of arcuate permanent magnets are positioned in angularly related adjacent positions to surround the outer periphery of a shaft mountable rotor core and a plastic molded sleeve encapsulates the exposed outer peripheral surfaces of the magnets to secure them in fast position on the core.
183 Citations
20 Claims
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1. A method for manufacturing a shaft mounted rotor assembly for an electric motor comprising:
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mounting a plurality of permanent magnets in angularly related adjacent positions on a cylindrical bored rotor core having inner and outer peripheral surfaces to substantially surround said outer peripheral surface of said core in a core/magnets assembly; supporting said cylindrical core/magnets assembly in a preselected position by support means inserted in said core to extended along said inner peripheral surface of said core; encasing said core/magnets assembly in an opposed pair of cooperative mold members contoured to matingly surround the outer peripheral surfaces of said permanent magnets in preselected spaced relation therewith providing a space therebetween; and injecting a plastic molding material into said space between said molds and the outer peripheral surfaces of said magnets to encapsulate said magnets in a unified, integral plastic molded sleeve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for manufacturing a shaft mounted rotor assembly for an electric motor comprising:
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adhesively mounting a plurality of permanent magnets in angularly related spaced positions on a rotor core having a plurality of longitudinally extending peripheral slots so that said rotor core slots are aligned with the spaces between said angularly mounted permanent magnets and the outer ends of said magnets extend the ends of said rotor core; encasing said rotor core/permanent magnet assembly in an opposed pair of cooperative mold members engaging in a plane extending substantially parallel the rotational axis of said rotor core and contoured to surround the outer peripheral wall and the outer ends of said permanent magnets in preselected spaced relation therewith, said rotor core/magnets assembly being encasingly supported by a pair of opposed reciprocally urged mandrels extending from said opposed pair of cooperating mold members through opposed ends of said core along the inner peripheral wall of said rotor core; preheating the opposed pair of cooperating mold members and rotor core/magnets assembly to temperatures within the range of approximately 200°
F. to 250°
F.;injecting a PBT polyester plastic material preheated to a temperature of approximately 510°
F. at a sufficiently low pressure to prevent damage to said rotor core/permanent magnets assembly and promptly fill the space between said molds and the outer peripheral surface and ends of said magnets to encapsulate said magnets in a plastic molded sleeve;allowing said plastic molded sleeve to set; withdrawing said support mandrels; and separating said engaging molds to remove said plastic encapsulated rotor core/permanent magnets assembly.
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Specification