| 摘要 |
PROBLEM TO BE SOLVED: To obtain an eddy current reduction gear having a small overall size, excellent heat dissipation properties and a high brake capacity. SOLUTION: The eddy current reduction gear comprises a brake disc 2 coupled with a rotary shaft 4, a nonmagnetic guide tube 3 having a cavity of rectangular cross-section disposed at a nonrotational part, e.g. the chassis, a nonmagnetic cover plate 8 disposed closely to the brake disc 2 while closing the end part of the guide tube 3, at least two nonmagnetic magnet supporting rings 5, 15 contained in the cavity of the guide tube 3 such that at least one of them is rotatable forward and reversely whereas the other is stationary, a large number of magnets 6, 16 coupled to the magnet supporting rings 5, 15 at a constant interval in the circumferential direction, and ferromagnetic members 7, 17 disposed to abut on the pole face at the opposite end parts of each magnet 6, 16 in the circumferential direction with the forward end face thereof being located closely to a cover plate 8. The eddy current reduction gear further comprises means for turning the magnet supporting ring 5 to a brake position where the magnets 6, 16 of the inner and outer magnet supporting rings 5, 15 overlap in the radial direction and a nonbrake position where they are shifted by one half of the arranging pitch in the circumferential direction.
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