| 摘要 |
PROBLEM TO BE SOLVED: To ensure rapidity and the certainty of speed change at swinging of a swing arm supported swingably at a pivot portion and to increase the degree of freedom of positioning of the pivot portion on a vehicle frame. SOLUTION: This bicycle includes vehicle frames 2 and 3 on which a pivot 7 is placed to support swingably a swing arm for pivoting a rear wheel, a drive sprocket 31 that is rotated and driven by a crank shaft 11 and a speed change device T having a plurality of gear change sprockets 41 to 47. The speed change device T includes an output shaft 24 supported rotatably on a case 20 of the device T fixed on the frames 2 and 3, and a chain 48 wound between the driving sprocket 31 and an operating sprocket that is selected from the sprockets 41 to 47 alternatively by a derailleur 60 of a speed change switching mechanism M2. The output shaft 24 is driven and connected to the rear wheel via a chain 16 would around the driven sprocket 15. COPYRIGHT: (C)2004,JPO
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