Hitachi Metals, Ltd.

Hiromitsu Ohhashi

Junichi Sutani

Masahiro Mita

Cylindrical outer and inner rotors coaxially supported so as to be rotatable, and a cylindrical stator interposed between the rotors are provided, and rotational torque is transmitted between the outer rotor and the inner rotor by interaction between: a plurality of magnets uniformly arranged on the inner circumference of the outer rotor; a plurality of magnets uniformly arranged on the outer circumference of the inner rotor; and a plurality of magnetic bodies juxtaposed at equal intervals in the circumferential direction of the stator. Rod-shaped magnetic bodies extending in the axial direction of the stator are used, and each magnetic body is placed in skew arrangement with a deviation amount in the circumferential direction corresponding to 1/12 to &#xbc; of the juxtaposition pitch in the circumferential direction between one axial end and the other axial end. Such arrangement can effectively reduce cogging torque, and realize stable power transmission under small torque fluctuation while ensuring high torque density.

Magnetic gear device

The magnetic gear device is equipped with a first magnet row in which a plurality of magnetic pole pairs are arranged at substantially equal intervals in a specific direction; a second magnet row which is opposed to the first magnet row and in which a plurality of magnetic pole pairs are arranged at substantially equal intervals in the specific direction at a pitch shorter (or longer) than that of the first magnet row; and a magnetic body row which is disposed between the first magnet row and the second magnet row and in which a plurality of magnetic bodies are arranged at substantially equal intervals in the specific direction, wherein a distance between the plurality of magnetic bodies and the second magnet row in the opposing direction is shorter (or longer) than a distance between the plurality of magnetic bodies and the first magnet row.

Magnetic gear device having a plurality of magnetic bodies arranged in a particular configuration

This coupling device includes a magnet rotator and a yoke-side member, while a conductor portion of the yoke-side member has a plurality of first conductor portions at least on a side opposed to magnets. A yoke of the yoke-side member is arranged at least on the side opposed to the magnets in a clearance between the plurality of first conductor portions. The ratio of the circumferential length of each of the first conductor portions to the circumferential length of the yoke is at least 1/1.4.

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Takasaki, Japan

Hiromitsu Ohhashi