| 摘要 |
<p>A power-assisted bicycle capable of simplifying a torque detecting mechanism, saving a space, and reducing a weight sufficiently, wherein a one-way clutch (72) transmitting only the rotation of a drive shaft (4) in the direction of moving forward the bicycle to a sprocket (70) is disposed inside a hollow cylindrical tube part (82) of the sprocket (70), on the sprocket surface on the opposite side of the one-way clutch, a bearing (74) is fitted onto the outer periphery of the cylindrical tube part (82) and a disc spring (76) having an elasticity holds the sprocket (70) through the bearing, the disc spring (76) is disposed fixedly to a body and a strain gauge (80) detecting the stress-strain of the disc spring (76) is installed on the surface of the body and, when the drive shaft (4) is rotated by a pedaling torque, the one-way clutch (72) provides the sprocket (70) with an axial pressing force, and the strain gauge (80) detects the stress-strain of the disc spring (76) receiving the force, i.e., the physical quantity related to the pedaling torque.</p> |
