| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tread force detecting device of a power-assisted bicycle which is improved in the detection accuracy of tread-force torque and linearly adds assistant power even if strong tread-force torque is applied to a crank shaft. <P>SOLUTION: The tread force detecting device (38) of a power-assisted bicycle (10) has the crank shaft (48) rotatably and pivotally supported by bearings (128, 130) at both ends, and is provided, between the bearings (128, 130), with a magnetostriction sensor (110) that is rotated by receiving the tread force from the crank shaft (48) at one side and detects the torsion of the outer circumference of a hollow torque transmission member (102) connected to a rear wheel drive member (46) at the other side. In the tread force detecting device, the hollow torque transmission member (102) rotates by receiving the tread force from the one side, and is provided with: a first hollow member (118) provided with the magnetostriction sensor (110) at the outer circumference thereof; and a second hollow member (120) fitted with the first hollow member (118) at the other end side of the first hollow member (118), and connected to the rear wheel drive member (46) at the other side set at the opposite side of the fitted part thereof. <P>COPYRIGHT: (C)2012,JPO&INPIT |
