FREE WHEEL HUB PROVIDED WITH MAGNETOELASTICITY SENSOR, AND BICYCLE PROVIDED WITH FREE WHEEL HUB, ELECTRIC ASSIST BICYCLE, HIGH SPEED ELECTRIC ASSIST BICYCLE OR POWER ASSIST BICYCLE

摘要

PROBLEM TO BE SOLVED: To provide a bicycle, a power-assisted bicycle, a high speed power-assisted bicycle or an electric bicycle which improve the measurement of torque acting on a freely traveling wheel.SOLUTION: A free wheel 2 includes a rotating hub shell 6 for carrying a freely traveling wheel. Torque is transmitted to the rotating hub shell via a torque transmission member 12. At least one magnetoelasticity active region R1 is directly or indirectly mounted on a part of the torque transmission member in such a manner that the acted torque is transmitted to an active region including at least one magnetic polarization region or forms a part of the torque transmission member. Magnetic polarization is gradually formed into a spiral shape as the acted torque increases. Magnetoelasticity sensor means having at least one magnetic field sensor S11 is arranged near at least one magnetoelasticity active region in order to output a signal corresponding to a magnetic flux resulting from the torque generated from the magnetic polarization region.