The rear suspension with a flexible torsion beam is particularly suitable for small and medium-sized front-wheel drive cars. Its elements do not take up much space, which makes it easier for the designer to plan the location of the exhaust system, spare wheel and fuel tank, with sufficient space in the luggage compartment. Coaxial shock absorbers with springs are easy to install, are of considerable height, but they do not reduce the width of the trunk
THE CONDUCTIVE TORSION BEAM
Coupled wishbones are connected by a crossbeam, mostly open section (np. in the shape of a triangle, the letters U or Ω), with high transverse stiffness and relatively low torsional stiffness, located in front of the axle of the rear wheels. It transmits bending moments, resulting from the action of vertical and lateral forces, and at the same time it is susceptible to twisting caused by mutual angular displacements of the rockers. It can also act as a stabilizer. The unsprung masses are small. There is no lifting of the rear of the car during braking. In general, designers manage to achieve more than satisfactory suspension comfort. An additional advantage of such a system is the possibility of separating it into one assembly module with a small number of components, simple and cheap for mass production. The disadvantage is the maintenance of the car's oversteer characteristics, caused by lateral forces, largely dependent on the flexibility of the beam-to-body elastic attachments. In addition, high loads on the welds connecting the wishbones to the beam limit the permissible load on the rear axle.
DEPENDENT OR INDEPENDENT.
Suspension with coupled longitudinal arms connected by a flexible torsion beam is sometimes called semi-dependent, which, admittedly, accurately reflects the nature of his work and the construction diagram, but it is sometimes criticized by technical purists, according to which only independent or dependent suspensions are distinguished, without any intermediate forms. We can assume, that the solutions used, for example. in Fiat Punto I or Mercedes A-Klasse, in which the subframe is attached to the body at four points and consists of longitudinal supports connected by a transverse tube and are in fact independent suspensions, a np. a rigid driving axle cooperating with leaf springs (np. Polish) this, in turn, is definitely a dependent suspension. The systems used, for example, in. in the products of the VW group (Passat, Golf, Skoda Fabia i in.), Ford (The) and Renaultach (Kangoo and Megane with four torsion bars and Clio II with coil springs). The mutual influence of the left and right wheel movements depends then on the beam stiffness, however, it is not so obvious, as for the classic rigid axle.