Sensor, drive force auxiliary device using the sensor, and torque sensor zero point adjusting mechanism of the drive force auxiliary device

A drive force auxiliary device, the drive force auxiliary device comprising:

• human power drive means configured by disposing a drive force transmitting mechanism having first and second rotors on the outer periphery of a crank shaft to which leg power is transmitted, and the drive force transmitting mechanism includes a first one-way clutch and an elastic member for transmitting human power drive force,
• auxiliary drive means configured by disposing a motor and a reduction gear mechanism, and the drive force from the motor being added to the drive force transmitting mechanism on the outer periphery of the crank shaft through a second one-way clutch,
• a torque sensor for detecting by a rotation angle sensor a difference of rotations of the first and second rotors, which are disposed at the front and rear of a drive force transmitting route of the elastic member, wherein
• the rotation angle sensor comprises a detection shaft, a detection disc which is fixed to the detection shaft, a magnetic piece which is fixed to the outer circumference edge of the detection disc, a yoke which is disposed to hold the magnetic piece in a predetermined shaped gap, and the magnet and the magnetic detecting element both fixed to the yoke, wherein
• the magnet and the magnetic detecting element are fixed with a predetermined distance between them and the magnetic piece passes through the predetermined shaped gap having the predetermined distance during the rotation of the detection disc, and rotation caused by the difference of rotations of the first and second rotors is transmitted to the detection shaft of the rotation angle sensor.