| 摘要 |
<p>A continuously variable friction drive transmission (13) for a bicycle (10) is provided having a driver plate (24) and a rim driver (32) with matching lateral conical surfaces (25 and 43). A transmission driver wheel (28) is selectively positioned between the rim driver (32) and driver plate (24) whereby the position of the transmission driver wheel (28) along a shifting arm (31) determines the speed ratio. The shifting arm (31) is rotatably coupled to the drive axis of the driver plate (24) and is parallel to the tapered conical surface (25) of the driver plate (24) to thereby always maintain the transmission driver wheel in contact with the driver plate (24). When the driver plate (24) ceases to rotate and the rim driver (32) continues to rotate, the force on the transmission driver wheel (28) automatically rotates the shifting arm (31) disengaging the transmission driver wheel (28) from the rim driver (32) thereby allowing the bicycle (10) to freewheel. The transmission driver wheel (28) reengages when the driver plate (24) again rotates at a speed at least equal to the rim driver (32).</p> |
