Motor with rotor holder having first and second magnets with different intervals to holder
A motor includes a stationary unit including a stator and a rotation unit including a magnet unit disposed radially outward of the stator and a cylindrical rotor holder. The magnet unit is held on a radially inside surface of the rotor holder. The magnet unit includes first magnets each of which has N and S poles magnetized in a radial direction, and second magnets each of which has N and S poles magnetized in a circumferential direction. Magnetic poles of radially inner end portions of the first magnets adjacent to each other in the circumferential direction via the second magnet are different from each other. Magnetic poles of circumferential end portions of the second magnets adjacent to each other in the circumferential direction via the first magnet are different from each other. An interval is provided between a radially outside surface of each first magnet and the radially inside surface of the rotor holder, and between a radially outside surface of each second magnet and the radially inside surface of the rotor holder.
1. A motor comprising:
a stationary unit including a stator annularly surrounding a vertically extending central axis; and
a rotation unit including a magnet unit disposed radially outward surface of the stator;
wherein the rotation unit further includes a cylindrical rotor holder extending in an axial direction;
the magnet unit is held on a radially inside surface of the rotor holder;
the magnet unit includes a plurality of first magnets each of which has N and S poles magnetized in a radial direction, and a plurality of second magnets each of which has N and S poles magnetized in a circumferential direction;
each first magnet and each second magnet are adjacent to each other in the circumferential direction;
magnetic poles of radially inner end portions of the first magnets adjacent to each other in the circumferential direction via the second magnet are different from each other;
magnetic poles of circumferential end portions of the second magnets adjacent to each other in the circumferential direction via the first magnet are different from each other;
a first interval is provided between a radially outside surface of each first magnet and the radially inside surface of the rotor holder, and a second interval is provided between a radially outside surface of each second magnet and the radially inside surface of the rotor holder;
when viewed in the axial direction, there is a closed space between side surfaces of the first magnets in the circumferential direction and side surfaces of the second magnets in the circumferential direction which is adjacent to the first magnets in the circumferential direction;
the closed space is bounded by the side surfaces of the first magnets, the side surfaces of the second magnets, and the radially inside surface of the rotor holder; and
an adhesive fins the closed space.
2. The motor according to claim 1 , wherein shapes of each first magnet and each second magnet are rectangular parallelepipeds.
3. The motor according to claim 1 , wherein at least one of at least a portion of the radially outside surface of each first magnet and at least a portion of the radially outside surface of each second magnet is opposite to the radially inside surface of the rotor holder via adhesive.
4. The motor according to claim 1 , wherein a radial gap between each second magnet and the stator is identical to a radial gap between each first magnet and the stator.
5. The motor according to claim 1 , wherein a circumferential length of each first magnet is longer than a circumferential length of each second magnet.
6. The motor according to claim 5 , wherein a radial length of each second magnet is longer than a radial length of each first magnet.