| 摘要 |
<p>A bicycle chainwheel (3) has a plurality of first teeth (4) spaced at (p- alpha ) from each other, where p is the chain pitch, and at least one second tooth (5) shaped differently from at least one of the first teeth. In the case where there is one second tooth (5), a sum P of the pitch between one of the first teeth (4) disposed immediately ahead of the second tooth (5) in a driving direction of the chainwheel and the second tooth, and of the pitch between the second tooth and another one of the first teeth disposed immediately behind the second tooth is greater than 2(p- alpha ). If desired, P may be approximately equal to 2(p- alpha ) + alpha . In the case where there is a plurality N of the second teeth (5) disposed adjacent to each other, where N is an integer greater than one, then P is preferably greater than (p- alpha ) x (N+1), and, if desired, approximately equal to ((p- alpha ) x (N+1)) + N alpha . In the case of a chainwheel having missing teeth, then a sum of the pitch P between a first one of the plurality of teeth and a second one of the plurality of teeth disposed adjacent thereto is preferably greater than (p- alpha ) x (N+1), where N is an integer greater than zero. <MATH></p> |
