Magnetic coupling device
A magnetic coupling device includes a driving magnet array having multiple annular sector-shaped, circumferentially arranged first permanent magnets, and a driven magnet array having multiple circular sector-shaped, circumferentially arranged second permanent magnets with pole surfaces facing pole surfaces of the first permanent magnets. The driven magnet array is rotated by the driving magnet array being rotated. A repulsion zone where a repulsive force acts is designed to have an area that is 5% to 15% of that of an attraction zone where an attractive force acts between a specific first permanent magnet and a specific second permanent magnet, with a radial first centerline of the specific first permanent magnet overlapping a radial second centerline of the specific second permanent magnet so that opposite poles face each other, including between first and second permanent magnets respectively adjacent the specific first and second permanent magnets with overlapping the centerlines.
1. A magnetic coupling device, comprising:
a driving magnet array having a plurality of first permanent magnets in an annular sector shape arranged to have alternating polarities along a circumferential direction; and
a driven magnet array having a plurality of second permanent magnets in an annular or circular sector shape arranged to have alternating polarities along a circumferential direction and to have pole surfaces facing pole surfaces of the first permanent magnets,
wherein the driving magnet array is configured to be rotated, and the driven magnet array is configured to be rotated when the driving magnet array is rotated,
wherein when a first centerline in a radial direction of an arbitrary one of the plurality of first permanent magnets overlaps a second centerline in a radial direction of an arbitrary one of the plurality of second permanent magnets so that opposite poles of the respective driving magnet array and driven magnet array face each other,
a repulsion zone where a repulsive force acts has an area that is in a range of 5% to 15% of an area of an attraction zone where an attractive force acts, wherein the repulsion zone includes a first permanent magnet adjacent the arbitrary one of the plurality of first permanent magnets and a second permanent magnet adjacent the arbitrary one of the plurality of second permanent magnets.
2. The magnetic coupling device according to claim 1 , wherein the first permanent magnets are arranged along a circumferential direction with space between adjacent first permanent magnets due to one or both of (i) surface roughness of the adjacent first permanent magnets and (ii) errors in assembly or production, and wherein the second permanent magnets are arranged along a circumferential direction with space between adjacent second permanent magnets due to one or both of (a) surface roughness of the adjacent second permanent magnets and (b) errors in assembly or production.
3. The magnetic coupling device according to claim 1 , further comprising a mechanism configured to move the driven magnet array along a radial direction of the first permanent magnets.
4. The magnetic coupling device according to claim 1 , further comprising a pole piece comprising a ferromagnet provided on pole surfaces of the first permanent magnets and the second permanent magnets.
5. The magnetic coupling device according to claim 2 , further comprising a mechanism configured to move the driven magnet array along a radial direction of the first permanent magnets.
6. The magnetic coupling device according to claim 2 , further comprising a pole piece comprising a ferromagnet provided on pole surfaces of the first permanent magnets and the second permanent magnets.
7. The magnetic coupling device according to claim 3 , further comprising a pole piece comprising a ferromagnet provided on pole surfaces of the first permanent magnets and the second permanent magnets.
8. The magnetic coupling device according to claim 5 , further comprising a pole piece comprising a ferromagnet provided on pole surfaces of the first permanent magnets and the second permanent magnets.