| 摘要 |
The present invention is directed to an integrated crank assembly. Preferably, the integrated crank assembly includes a bottom bracket spindle having an outside diameter of greater than 29 mm, a wall thickness of less than about 2 mm, and a wall thickness to outside diameter ratio of greater than about 11. In one embodiment, the assembly further includes a bottom bracket shell for receiving the spindle and bearing for rotatably supporting the spindle in the shell, where the bearings are mounted directly to the shell. Additionally, preferably the integrated crank assembly features crank arms with an optimized arch roof design. The crank arm includes two crank arm halves that are bonded together. In one embodiment, the wall thickness in each crank arm half varies continually along the length of the crank arm half. The wall thickness is optimized to carry the loads equally along the crank arm. Also, there may be total wall asymmetry throughout the crank arm. Thus, if the outside profile of the crank arm is asymmetric between halves, then the wall thickness can also be asymmetric because it is optimized for carrying loads equally along the length of the crank arm.
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