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US 5,345,133 AGranted
Electric motor
AssigneeOkuma Corporation
InventorAkiyoshi Satake
Life of this patent
Estimating the term…
Abstract
High permeability material plates used to construct the stators and the rotor of a motor are formed of the same material, thus reducing the number of fabrication processes and material cost. Also, the rotor containing permanent magnets is cylindrical and two stators are arranged around the inner circumference and the outer circumference of the permanent magnets, respectively, thereby increasing efficiency.
Claims3
An electric motor comprising:
- a rotational shaft which rotates about a rotational axis thereof;
- a cylindrical rotor including a plurality of permanent magnets embedded within a high permeability material, said plurality of permanent magnets spaced apart and juxtaposed along a circumference of said cylindrical rotor with said high permeability material;
- a coupling member made of a non-high permeability material which couples said rotational shaft to said cylindrical rotor such that the rotational axis of said rotational shaft coincides with a rotational axis of said cylindrical rotor;
- an outer cylindrical stator, formed of said high permeability material, which is coaxial said cylindrical rotor and has an inner peripheral surface confronting an outer peripheral surface of said cylindrical rotor, said outer cylindrical stator including a plurality of spaced apart outer stator teeth protruding radially inward towards said cylindrical rotor and extending lengthwise from one end of said outer cylindrical stator to another end of said outer cylindrical stator, said plurality of spaced apart outer stator teeth being spaced from said outer peripheral surface of said cylindrical rotor and defining grooves therebetween which are spaced apart and juxtaposed along said inner peripheral surface of said outer cylindrical stator, wherein a total number of said plurality of spaced apart outer stator teeth exceeds a total number of said plurality of permanent magnets;
- an inner cylindrical stator, formed of said high permeability material, which is coaxial with said cylindrical rotor and has an outer peripheral surface confronting an inner peripheral surface of said cylindrical rotor, said inner cylindrical stator including a plurality of spaced apart inner stator teeth protruding radially outward towards said cylindrical rotor and extending lengthwise from one end of said inner cylindrical stator to another end of said inner cylindrical stator, said plurality of spaced apart inner stator teeth being spaced from said inner peripheral surface of said cylindrical rotor and defining grooves therebetween which are spaced apart and juxtaposed along said outer peripheral surface of said inner cylindrical stator;
- a plurality of windings respectively extending lengthwise along and within said grooves defined by said inner stator teeth and outer stator teeth.
3 more elements
Dependencies are inferred from the claim text.