Motor

A motor comprising:

• a rotary shaft;
• a yoke coupled to the rotary shaft;
• a stator disposed between the rotary shaft and the yoke;
• a first magnet and a second magnet disposed in the yoke;
• and
• a circuit board on which a first Hall sensor is disposed to correspond to the first magnet and a second Hall sensor is disposed to correspond to the second magnet,
• wherein the second magnet is disposed outside the first magnet in a radial direction,
• wherein the second magnet includes a plurality of split magnets and one index magnet,
• a width of the split magnet in a circumferential direction is the same as a width of the index magnet in the circumferential direction,
• each of the split magnets and the index magnet are formed by combining a first pole and a second pole,
• a width of the first pole of the split magnet in the circumferential direction is the same as a width of the second pole of the split magnet in the circumferential direction, and
• a width of the first pole of the index magnet in the circumferential direction is different from a width of the second pole of the index magnet in the circumferential direction,
• wherein a ratio of a width of the first pole of the index magnet to a width of the second pole of the index magnet is N:M;
• a sum of the N and the M is 10;
• the N is in a range of 3.1 to 3.9;
• and
• the M is in a range of 6.1 to 6.9.