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US 8,013,489 B2Granted
Small DC motor
AssigneeMinebea Motor Manufacturing Corporation
InventorMinoru Kuroda
Life of this patent
Estimating the term…
Abstract
A small DC motor includes a motor frame having a cylindrical portion, the cylindrical portion having a constant thickness and having a cross section in a shape that comprises four sides and connecting portions, each of the connecting portions connecting adjacent two of the four sides and being located inward from a corresponding corner in a quadrangle comprising the four sides; and a magnet having a circumferential surface on an inside thereof and having conformable contact with the motor frame on an outside thereof.
Claims3
A small DC motor, comprising:
- a motor frame having a constant thickness and having two ends and a side wall;
- wherein the side wall surrounds a magnet and includes four straight portions and at least four connecting portions, the motor frame being a magnetic material and being a magnetic constituent portion of the motor;
- wherein each of the connecting portions is located between adjacent two of the four straight portions;
- wherein the magnet includes at least four poles and has an outer surface conforming to the motor frame and an inner surface forming a circular opening and wherein the width of the magnet between the inner and outer surface varies;
- a rotor having a shaft and rotatably disposed in the circular opening,
- wherein the side wall includes the same number of connecting portions as the number of poles contained in the magnet, wherein each of the connecting portions is a segment of a circle concentric with a center of the shaft;
- wherein an air gap provided between the inner surface of the magnet and the rotor has a constant distance.
4 more elements
Dependencies are inferred from the claim text.