Coupling profile between a central axle of a bottom bracket of a bicycle transmission and a pedal crank

摘要

The coupling profile (30) comprises, in a plane transversal to the axis (X) of the bottom bracket, outer arcs (CD) belonging to the same outer circumference (31) of the coupling, each of such outer arcs (CD) being flanked and filleted on one side to a power transmission line (AC) and on the opposite side to an idle line (DA), in which the power transmission line (AC) and the idle line (DA) are symmetrical with respect to the outer arc (CD) that separates them. The outer arc (CD) has an angular extension (´) about the axis (X) of the bottom bracket equal to at least one tenth of the angular extension (³) of the power transmission line (AC), and the power transmission line (AC) and the idle line (DA) are filleted to the outer arc (CD) according to an angle (²) smaller than 45°.