DC motor and manufacturing method for the same
First Claim
1. A DC motor comprising:
- a yoke having a polygonal cylindrical shape and having an inner wall surface provided with a plurality of consecutive flat surfaces;
a plurality of permanent magnets each having a flat plate shape and fixed on the respective flat surfaces in the inner wall surface of the yoke; and
an armature arranged rotatably within the yoke, wherein a dimension of each magnet along an axial direction of the yoke decreases toward an outer side from a center part of the permanent magnet.
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Accused Products
Abstract
A DC motor is provided with a yoke having a polygonal cylindrical shape and an inner wall surface provided with a plurality of consecutive flat surfaces, a plurality of permanent magnets each having a flat plate shape, being fixed on each flat surface on the inner wall surface of the yoke, and an armature arranged rotatably within the yoke. Each permanent magnet has a surface facing the armature. The surface has a rectangle shape provided with a symmetry center. Each permanent magnet is asymmetrical with respect to a line passing through the symmetry center and extending in an axial direction of the yoke. Accordingly, a dimension along the axial direction of the yoke in each permanent magnet decreases toward the outer side from a center part of the permanent magnet.
12 Citations
13 Claims
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1. A DC motor comprising:
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a yoke having a polygonal cylindrical shape and having an inner wall surface provided with a plurality of consecutive flat surfaces;
a plurality of permanent magnets each having a flat plate shape and fixed on the respective flat surfaces in the inner wall surface of the yoke; and
an armature arranged rotatably within the yoke, wherein a dimension of each magnet along an axial direction of the yoke decreases toward an outer side from a center part of the permanent magnet.
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2. A DC motor comprising:
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a yoke having a polygonal cylindrical shape and having an inner wall surface provided with a plurality of consecutive flat surfaces;
an armature arranged rotatably within the yoke; and
a plurality of permanent magnets each having a flat plate shape and fixed on the respective flat surfaces in the inner wall surface of the yoke, wherein each permanent magnet has a surface facing the armature, and the surface has a polygonal shape provided with a symmetry center or an oval shape, wherein each of the permanent magnets is asymmetrical with respect to a line passing through the symmetry center and extending in an axial direction of the yoke. - View Dependent Claims (3, 4, 5, 6, 7)
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8. A method for manufacturing a DC motor, wherein the DC motor comprises a yoke having a polygonal cylindrical shape and having an inner wall surface provided with a plurality of consecutive flat surfaces, an armature arranged rotatably within the yoke, and a plurality of permanent magnets each having a flat plate shape fixed on respective flat surfaces on the inner wall surface of the yoke, wherein each permanent magnet has a surface facing the armature, and the surface has a polygonal shape provided with a symmetry center or an oval shape, wherein each permanent magnet is asymmetrical with respect to a line passing through the symmetry center and extending in an axial direction of the yoke, the method comprising:
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fixing temporarily each of the permanent magnets on each flat surface on an inner wall surface of the yoke due to magnetic attraction from each magnet;
measuring motor characteristics including cogging torque;
rotating the permanent magnets with the symmetry center as a rotation center on the flat surface on the inner wall surface of the yoke when motor characteristics as measured are deviate from a value set preliminarily; and
fixing each of the permanent magnets on each of the flat surfaces in the inner wall surface of the yoke with an adhesive.
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9. A DC motor comprising:
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a yoke having a cylindrical shape and an inner wall surface;
an armature arranged inside the yoke, including an armature core having a cylindrical shape comprising an outer circumferential surface, and eight teeth radially extending from the outer circumferential surface;
a commutator comprising twenty-four segments, the commutator being arranged on an inner side of the armature core; and
eight coils wound around the respective teeth with concentrated-winding, each coil being connected to at least one of the segments, wherein the coils are connected in such a way as to form one closed loop;
an anode side power supply brush and a cathode side power supply brush each coming into a slidable contact with at least one of the segments of the commutator, the brushes causing the armature to rotate by supplying drive supply power for the armature through the commutator;
a plurality of magnets each having a flat plate shape, being set on the inner wall surface of the yoke at equiangular intervals, wherein each magnet includes;
a surface facing the armature; and
a magnetic flux extending in a direction perpendicular to the surface; and
a center axis, wherein, on the surface of each magnet, an angle formed by a pair of line segments connecting both ends in a direction perpendicular to the axial direction of the yoke to the center axis is set in a range from 34.5 degrees to 52 degrees. - View Dependent Claims (10, 11, 12, 13)
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Specification