BUILDING & MOUNTING THE STRUCTURES 3-7 E UROCARGO Euro 4/5 The type of section of the runner must be determined with due consideration to the function of the subframe and to the type of structure that is above it. It is advisable to use open U-sections if the subframe has to adapt itself elastically to the vehicle’s chassis, and to use box-type sections when added rigidity is needed. Proper care must be taken to ensure a gradual change from the box- type section to the open type section. Some examples on how this can be achieved are shown in Figure 3.3. Figure 3.3 91520 It is necessary for continuous support to be made between the sections of the subframe and those of the vehicle.
Do not put any rubber elements in between the chassis frame and subframe. The specified dimensions for the structural members of the various types of body are recommended minimum values that, as a rule, hold for vehicles with standard wheelbases and rear overhangs. In all cases, similar sections can be used with moments of inertia and resistance that are no lower. These values can be obtained from the technical documentation of the section manufacturers.
Bear in mind that the moment of inertia is mainly important for the flexional rigidity as well as for the portion of bending moment to be taken, depending on the connection used; while the modulus of resistance is a decisive value for the strain on the material. Elements making up the subframe Print 603.93.431 Base - January 2008