| 摘要 |
<p>A crank assembly (10) for a bottom bracket of a bicycle (100), comprises a shaft (20) extending along a longitudinal axis (X-X), at least one pedal crank (30, 40) associated with at least one free end (20a, 20b) of said shaft (20), first front coupling means (60) formed on said shaft (20) and second front coupling means (50) formed on said at least one pedal crank (30, 40), said first and second front coupling means being coupled together. In particular, the aforementioned first and second front coupling means comprise respective front toothings. The front coupling is located in an end zone (201a, 210b), or on the outside, of a housing box (210) of the shaft (20) of the bottom bracket formed in the frame (101) of the bicycle (100). The front coupling introduces a structural discontinuity between pedal crank and shaft, for which reason the bending load exerted on the pedal crank during pedalling is transmitted to the shaft to a very small degree. Such a structural discontinuity is located at the interface between shaft and pedal crank. The propagation of the bending stress is therefore interrupted at a point in which it is still minimal, given that at that point the arm of the bending torque is practically zero.</p> |
