| 摘要 |
PROBLEM TO BE SOLVED: To make an eddy current reduction gear easily manufacturable by integrally forming the thick-wall sections, corresponding to the conventional ferromagnetic plates with a guide pipe made of a soft magnetic or ferromagnetic material and demagnetizing the thin-wall sections between the thick-wall sections. SOLUTION: An eddy current reduction gear is provided with a pair of brake discs 3 coupled with a rotating shaft 2, a guide pipe 5 attached to a non-rotating section between the discs 3, has an internal space section having a rectangular cross section and is made of a nonmagnetic material, and at least one magnet support ring 8 which is supported in the internal space section of the pipe in a normally and reversely rotatable states. The reduction gear is also provided with many magnets 12, coupled with the ring 8 at regular peripheral intervals and magnetic plates provided at the portions facing the magnets 12 of both sidewalls of the pipe 5. Therefore, the discs 3 generate braking forces, when eddy current based on the magnetic field from the magnets 12 are supplied to the discs 3. The thick-wall sections 6 of at least one of the internal and external surfaces of both sidewalls of the pipe 5 made of a soft magnetic material are formed into magnetic plates, and the portions not facing the magnets 12 are formed in thin-wall sections 6a. In addition, the thin-wall sections 6a are changed into a nonmagnetic austenitic phase by diffusing nickel in the sections 6a through heating.
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