Back to results
US 8,264,112 B2Granted
Motor
AssigneeMinnebea 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.
Claims15
A motor comprising:
- a motor frame having an open end at one end thereof and an end plate portion at other end thereof, the motor frame being a magnetic material and being a magnetic constituent portion of the motor;
- a magnet disposed on an inner surface of the motor frame, 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 of the magnet;
- and
- an end cap attached to the open end of the motor frame,
- wherein the motor frame surrounds the magnet and includes four straight portions and at least four connecting portions,
- wherein each of the connecting portions is located between adjacent two of the four straight portions,
- wherein the motor frame 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, and
- wherein an air gap provided between the inner surface of the magnet and the rotor has a constant distance.
6 more elements
A motor comprising:
- a motor frame having an open end at one end thereof and an end plate portion at other end thereof, the motor frame being a magnetic material and being a magnetic constituent portion of the motor;
- a magnet disposed on an inner surface of the motor frame, 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 rotatably disposed in the circular opening of the magnet;
- and
- an end cap attached to the open end of the motor frame,
- wherein the motor frame surrounds the magnet and includes four straight portions and at least four connecting portions, wherein each of the connecting portions is located between adjacent two of the four straight portions,
- wherein each of the connecting portions is a segment of a circle that is concentric with a center of a rotation axis of the rotor, and
- wherein an air gap provided between the inner surface of the magnet and the rotor has a constant distance.
5 more elements
A motor comprising:
- a motor frame having an one end and the other end, the motor frame being a magnetic material and being a magnetic constituent portion of the motor;
- a magnet disposed in an inner surface of the motor frame, wherein the magnet includes an outer surface conformed to the inner surface of the motor frame and an inner surface and wherein the magnet includes minimum thickness portions having minimum thickness in a radial direction and maximum thickness portions having maximum thickness in the radial direction;
- a rotor rotatably disposed in a space surrounded by the inner surface of the magnet;
- and an end cap attached to the one end of the motor frame,
- wherein the motor frame includes four straight portions corresponding to the minimum thickness portions of the magnet and four connecting portions corresponding to the maximum thickness portions of the magnet,
- wherein each of the connecting portions is located between adjacent two of the four straight portions and is a segment of a circle that is concentric with a center of a rotation axis of the rotor, and
- 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.