| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor that is flat, generates sufficient torque when rotated, and starts up in a short time.SOLUTION: The spindle motor includes a baseplate 21, a stator, a rotor hub 31 in the shape of a lidded cylinder, a rotor magnet 32 positioned radially outside of the stator and fixed to an inner circumferential surface of a sidewall part of the rotor hub 31, and a bearing mechanism. The rotor magnet 32 is of a neodymium bonded magnet and has a radial thickness of not less than 0.7 mm nor more than 1.0 mm, and the rotor magnet 32 has a radial distance to a stator core 221 of the stator of not less than 0.15 mm nor more than 0.20 mm. A torque constant Kt of torque generated between the stator and the rotor magnet 32 is not less than 4 mN*m/A nor more than 6 mN*m/A, and a motor constant Km is not less than 2 mN*m/(A*√Ω) nor more than 4 mN*m/(A*√Ω). |
