To assist pedal-stepping force being connected to the chain sprocket of a rotor such as a bicycle by synchronizing the rotor where a permanent magnet is mounted and another rotor where the permanent magnet is mounted for generating the attraction force and repulsion force of magnetism.
Eight permanent magnets are arranged at a timing pulley 82 of a chain sprocket 11 while N and S poles are arranged alternately at an equal circumference division. A total of two permanent magnets 86 of N and S poles are arranged at a circular plate 85 being fixed to a timing pulley 84 at an equal circumference division so that the N pole is located at the center of the N and S poles of a permanent magnet 83. From the above configuration, the N pole of the permanent magnet 83 and that of the permanent magnet 86 repel each other, and the S and N poles are attracted each other. When the S pole of the permanent magnet 85 is rotated by 45 degrees and reaches the previous N-pole position, the S pole of the permanent magnet 86 is rotated by 180 degrees, and the S pole of the permanent magnet 83 and that of the permanent magnet 86 repel each other, and the N and S poles are attracted each other, thus assisting the rotation of the chain sprocket 11.
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YAMAGUCHI MASAKI
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YAMAGUCHI NAOKI
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