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US 4,250,128 AGranted
Processes and apparatuses for preparing permanent magnet stators
AssigneeMagna Motors Corporation
InventorJohn H. Meckling
Life of this patent
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AssigneeMagna Motors Corporation
InventorJohn H. Meckling
Estimating the term…
Annular magnets, primarily for motor stators, are centrifugally cast from particulate materials and synthetic plastic materials. Iron particles and ferrite particles stratified during the spin casting procedures so that the former provide an outer stratum that serves as a yoke in the permanently magnetized structure. The anisotropic ferrite particles are magnetically oriented during casting by a rotating center magnet with the aid of bucking magnets that also rotate and serve to confine the field of the center magnet to the cavity area. Apparatus for carrying out the process is disclosed and includes means for introducing the plastic and particulate materials to the mold cavity while the mold is rotating as well as mold arrangements that facilitate material introduction by the creation of reduced pressure conditions in the cavity during the rotation of the mold. Permanent magnets or electromagnets may be used for ferrite particle orientation and compound magnets made from laminated and facially polarized rubber magnetic sections and which are arcuately bent are disclosed.
An apparatus for centrifugally casting a stator component for a dynamoelectric machine comprising a mold having an axis of rotation, a core component extending along said axis, and an annular cavity surrounding said core for receiving material to be cast therein, and means connected to the mold for rotating said mold about said axis, and core component comprising magnetic means having circumferentially spaced apart arcuate pole faces which are radially offset from said axis and face said cavity.
A process for making a permanently magnetized annular structure comprising confining a deformable mass of hardenable synthetic plastic material that contains dispersed particles of a magnetically attractable and anisotropic ferrite material in an annular cavity of a mold, rotating the mold about the axis of the cavity while subjecting the particles to a magnetic field which rotates with the mold about said axis and traverses a path through the cavity between circumferentially spaced and outwardly facing pole faces that are of opposite polarity and confront the cavity radially outwardly of said axis, thereby to magnetically orient and compact said particles in a region extending through the cavity between said pole holes, and thereafter hardening said plastic material to maintain the magnetic orientation and particle compactness in said region.
A process for making a permanently magnetized stator structure for a dynamoelectric machine comprising stirring particles of magnetically attractable and anisotropic ferrite material in a magnetic field, thereafter confining a mixture in an annular cavity of a mold which includes hardenable liquid synthetic plastic material containing dispersed particles subjected to said stirring and particles of ferromagnetic material having a density than said anisotropic material, rotating the mold about the axis of the cavity while subjecting the particles in the mixture to a magnetic field which rotates with the mold about said and traverses a path through the cavity between circumferentially spaced and outwardly facing pole faces that are of opposite polarity and confront the cavity radially outwardly of said axis, thereby to magnetically orient and compact the particles of anisotropic material in a region extending through the cavity between said pole faces and to centrifugally orient the ferromagnetic particles into an annular stratum located contiguous to and radially outwardly of said region, and thereafter hardening said plastic material to maintain said region and stratum.
A process for making a permanently magnetized stator structure for a dynamoelectric machine comprising rotating a mold having an annular cavity about the axis of said cavity, introducing a synthetic plastic material of the cavity of the rotating mold, introducing particles of magnetically attractable anisotropic material to the cavity of the rotating mold, subjecting the particles introduced to the cavity to a magnetic field which rotates with the mold about said axis and traverses a path through the cavity between circumferentially spaced and outwardly facing pole faces that are of opposite polarity and confront the cavity radially outwardly of said axis, and thereafter hardening said plastic material while said mold is rotating.
Dependencies are inferred from the claim text.