Magnetic gear mechanism
The present invention is intended to provide a magnetic gear structure that realizes a magnetic gear that transmits a torque efficiently by reducing eddy currents generated in the interior of magnets. In order to solve the subject described above, in the magnetic gear structure, a structure in which magnets are arranged in the interior of an iron core in an inner rotor portion. Bonded magnets formed by molding, for example, NdFeB powder may be used as the magnets. Since the influence of the eddy current on the side of an outer rotor having a larger pole number is large, a structure in which the magnets are arranged in the interior only of an outer rotor portion having a larger pole number is also applicable. In addition, the magnets to be embedded may be divided into a plurality of pieces. The finer the division of the magnets, the less eddy currents are generated, so that a method of further fining down and assembling the same is also effective. Further reduction of the eddy currents is possible by laminating the plate-shaped magnets having a thickness equivalent to an electromagnetic steel plate in the axial direction.
1. A magnetic gear mechanism comprising two rotors each including permanent magnets having a plurality of poles; and pole shoe members formed of a first soft magnetic material, having a plurality of poles, and arranged between the rotors, wherein rotation is transmitted by modulating magnetic fluxes having respective ratios of magnet pole numbers by pole shoe members thereof, wherein
the rotors each are formed of a laminated member of a second soft magnetic material, and include the permanent magnets arranged in an interior of the second soft magnetic material,
a number of divisions of the magnets is differentiated between magnets in a first rotor of the two rotors having a larger number of poles and magnets in a second rotor of the two rotors having a smaller number of poles, and the number of divisions of the magnets in the first rotor having the larger number of poles is larger, and
the permanent magnets in the first rotor having the larger number of poles are arranged so as not to be exposed to a surface of the first rotor facing the pole shoe members that modulate the magnetic fluxes, wherein a portion of the second soft magnetic material is disposed between the permanent magnets and the surface of the first rotor facing the pole shoe members, and are divided into a plurality of pieces in the axial direction.
2. The magnetic gear mechanism according to claim 1 , wherein
the pole shoes include laminated electromagnetic steel plates and have a shape formed by being integrated in the circumferential direction with voids between the pole shoes by hollowing out as holes.