| US 7,579,745 B2 | ||
| Motor | ||
| Kensuke Yamada, Tachikawa (Japan); Yuuki Takahashi, Tama (Japan); Masami Ito, Hachioji (Japan); and Takeo Miyajima, Atsugi (Japan) | ||
| Assigned to Mitsumi Electric Co., Ltd., Tokyo (Japan) | ||
| Filed on Dec. 21, 2005, as Appl. No. 11/312,481. | ||
| Claims priority of application No. P2005-050353 (JP), filed on Feb. 25, 2005. | ||
| Prior Publication US 2006/0192454 A1, Aug. 31, 2006 | ||
| Int. Cl. H02K 23/04 (2006.01); H02K 1/00 (2006.01) | ||
| U.S. Cl. 310—269 [310/154.21; 310/154.22; 310/46; 310/154.01; 29/596] | 3 Claims |
| 1. A motor comprising:
a motor case;
a rotor, operable to rotate in a rotating direction on a central axis within the motor case, and provided with five teeth
that define five respective slots therebetween at regular intervals in the rotating direction; and
a pair of arc-shaped magnets, surrounding the rotor, and facing each other through the rotor,
wherein each of the magnets has an inner circumferential surface which faces the rotor, an outer circumferential surface which
faces an inner wall of the motor case, and end surfaces which connect the inner circumferential surface and the outer circumferential
surface;
wherein a value of a circumferential angle between any two adjacent slots with respect to the central axis of the rotor is
defined as the angle a,
wherein a value of a circumferential angle between the inner circumferential surface with respect to the central axis of the
rotor is defined as the angle b,
wherein a value of a circumferential angle between the outer circumferential surface with respect to the central axis of the
rotor is defined as angle c,
wherein the ratio of the angle a: the angle b: the angle c is 3:6:5, and
wherein a value of a circumferential angle between the end surfaces with respect to the central axis of the rotor becomes
smaller from the angle b to the angle c as the distance from a center of the rotor becomes larger.
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