US 5,691,681 AGranted

Method of producing a field magnet for a DC motor and a field magnet for a DC motor

AssigneeNakagawaseimitsukogyo Kabushikikaisha

InventorShougo Okugawa

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Abstract

A method of producing a field magnet for a DC motor is disclosed. A molding material is casted into a molding space which is between outer and inner molds. Field poles are formed by magnetizing poles on the outer peripheral surface of the inner mold, in portions which oppose the magnetizing poles. A magnetic path which connects the field poles with each other is formed in a thickness portion of the molding material by powder of a ferromagnetic material in the molding material.

Claims2

Dependent claims

A method of fabricating a field magnet for a DC motor, comprising the steps of:

(a) providing an outer mold of a nonmagnetic material having a hollowed inner portion formed in an annular shape to surround the outer periphery of the molding space for the field magnet;
(b) providing an inner mold of a nonmagnetic material having an outer peripheral face having an annular shape corresponding to the inner periphery of said outer mold for shaping the inner periphery of said field magnet, said inner mold having plural magnetizing poles disposed on the outer peripheral face thereof;
(c) said outer and inner molds being arranged so that the cylindrical molding space for the field magnet is formed between the inner face of the outer mold and the outer peripheral face of the inner mold with the magnetic fluxes emitted from the magnetizing poles passing through the outer and inner molds and the molding space therebetween;
(d) providing a mixture of ferromagnetic material and a binder as a molding material and filling said molding space with said molding material, directing magnetic flux between said magnetizing poles using said molding material in said molding space as a part of the magnetic path between said magnetizing poles to orient the axes of easy magnetization of particles of the ferromagnetic material in the direction of the magnetic fluxes with the ferromagnetic material which respectively opposes the magnetizing poles and on the side of the inner peripheral face being magnetized more intensely than the ferromagnetic material in the other portions, thereby configuring field poles;
and
(e) fixing the axes of easy magnetization of particles of the ferromagnetic material powder by solidifying the molding material while maintaining the axes of easy magnetization to be oriented in the direction of the magnetic fluxes, thereby simultaneously configuring the field poles and the magnetic path interposed between the field poles in the molding material.

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Dependencies are inferred from the claim text.

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Abstract

A method of fabricating a field magnet for a DC motor, comprising the steps of:

(a) providing an outer mold of a nonmagnetic material having a hollowed inner portion formed in an annular shape to surround the outer periphery of the molding space for the field magnet;
(b) providing an inner mold of a nonmagnetic material having an outer peripheral face having an annular shape corresponding to the inner periphery of said outer mold for shaping the inner periphery of said field magnet, said inner mold having plural magnetizing poles disposed on the outer peripheral face thereof;
(c) said outer and inner molds being arranged so that the cylindrical molding space for the field magnet is formed between the inner face of the outer mold and the outer peripheral face of the inner mold with the magnetic fluxes emitted from the magnetizing poles passing through the outer and inner molds and the molding space therebetween;
(d) providing a mixture of ferromagnetic material and a binder as a molding material and filling said molding space with said molding material, directing magnetic flux between said magnetizing poles using said molding material in said molding space as a part of the magnetic path between said magnetizing poles to orient the axes of easy magnetization of particles of the ferromagnetic material in the direction of the magnetic fluxes with the ferromagnetic material which respectively opposes the magnetizing poles and on the side of the inner peripheral face being magnetized more intensely than the ferromagnetic material in the other portions, thereby configuring field poles;
and
(e) fixing the axes of easy magnetization of particles of the ferromagnetic material powder by solidifying the molding material while maintaining the axes of easy magnetization to be oriented in the direction of the magnetic fluxes, thereby simultaneously configuring the field poles and the magnetic path interposed between the field poles in the molding material.

3 more elements