DOUBLE WISHBONE OR MCPHERSON SUSPENSION WITH TRANSVERSE LEAF SPRING AND DIMENSIONING METHOD THEREOF

摘要

Method for dimensioning a quadrilateral or McPherson suspension (S) with cross leaf spring (LS) defining a longitudinal development (Y), arranged parallel to a symmetrical vehicle axle defined by the suspension (S), having an intermediate point of reference (M), an end point (L/2) connected to a lower arm (AL) of the suspension and a constraint point (1/2), intermediate between the first two, constrained to a fixed part (C), said method comprising a step of defining the following distances measured along said longitudinal development (Y) starting from said intermediate point of reference (M) : - P = distance of the connection (X2) between lower arm (AL) and wheel hub (SP), - L/2 = distance from said end point (L/2) of the leaf spring (LS), - H = distance of the hinging between said first part of the lower arm and said fixed part (C), - 1/2 = distance of said intermediate constraint point (1/2); - a step of defining with d a difference/distance between H and L/2 and with b a difference/distance between H and P, - a step of defining R = b/ (b-d), - a step of defining ks = ksosp * R² [eq.l], where ks is the stiffness of the leaf spring upon symmetrical vertical loads and ksosp is the stiffness of the suspension upon symmetrical vertical loads, - a step of defining a thickness h of said leaf spring (LS) according to the following equations: - h = hO between said reference intermediate point (M) and 1/2, - h(Y) = 2* ( (Y- (costi) ) / (cost2) )^0-5 between 1/2 and L/2 [eq. 2 ], where Y is an independent variable, costi = 1015.00942 and cost₂ = -8.51224 and wherein the material of said leaf spring has a Young module comprised between 195 GPa and 210 GPa.