| 摘要 |
PROBLEM TO BE SOLVED: To drive the rotor of a brushless motor with sufficient torque, without generating vibration and noise, by so providing its rotor as to be protruded from the insertion hole of its stator core, and by setting to a numeric value falling within a specific scope the difference value between the distances ranging from the center of its stator core in the axial direction thereof to both the end surfaces of its rotor. SOLUTION: By forming a magnet rotor 1 so as to protrude it from an insertion hole 3a of a stator core 3, a Hall element is positioned separately by a fixed distance from the stator core 3 to prevent the Hall element from being affected by the leakage magnetic flux of the stator core 3. Also, when the distances ranging from a central plane X-X of the stator core 3 in the axial direction to both end surfaces (A), (B) of the magnet rotor 1 are selected respectively so as to be (a) and (b), their difference of±|a-b|is set within the range of -1.04 to 0.66. As a result, the positions of the magnetic poles of the magnet rotor 1 can be sensed accurately by the Hall element to obtain the sufficient driving force of a brushless motor, and its vibration and noise can be reduced, when it rotates. |
