Double wishbone or mcpherson suspension with transverse leaf spring and dimensioning method thereof

Abstract

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.

Description

technical field [0001] The invention relates to the field of vehicle suspensions, in particular to a method of dimensioning a quadrilateral or MacPherson suspension with transverse leaf springs, and to the suspension obtained by this method. Background technique [0002] Quad suspensions with transverse leaf springs have been used for many years, especially for the front suspension of industrial vehicles. [0003] To ensure optimum dynamic characteristics, these independent wheel suspensions are often supplemented by anti-roll bars, which connect the chassis to components of the suspension - such as lower arms, shock absorbers, etc. - to limit the vehicle's Rolling motion. [0004] Anti-roll bars have no effect when the suspension of the same axle is subjected to symmetrical vertical loads. On the other hand, the anti-roll bar cooperates with the suspension in a manner commensurate with the difference between the vertical loads acting on the suspension of the same axle. ...

AI Technical Summary

Problems solved by technology

[0009] According to the prior art, the above results have to be achieved by using anti-roll bars, where the associated elements of the anti-roll bar connect the bar to the vehicle body and to the suspension components, thus increasing the weight and size

[0010] On the other hand, the removal of such bars reduces the performance of the vehicle, especially in terms of bending

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