| 摘要 |
<p>A brushless motor which includes a stator (9) and a rotor (8) rotatably supported inside the stator. The rotor has a rotor yoke (10) formed by laminating a large number of steel plates, the rotor yoke has an even number of magnetic pole portions (8a) protruding outward, and a field magnet (11) is fitted to each of the magnetic pole portions or every other magnetic pole portions. A magnetic sensor (16) is disposed within the range in which the sensor (16) can directly detect a magnetic flux leaking outside from an end face (8b) of the rotor (8) and is less affected by irregular fluxes near the rotor end face (8b), so that this sensor can detect a peak point of a flux density around the rotor. A magnetic sensor is disposed within the range where the influences of the irregular fluxes are small. A magnet (17) to be detected is fitted to the rotor end face (8b), and a magnetic sensor (16X) for one direction and a magnetic sensor (16Y) for the other direction are disposed near the trajectory of rotation of the magnet to be detected, and these sensors are disposed in the opposite direction to the rotating direction of the rotor in the arrangement such that they are deviated from one another by predetermined angles.</p> |
