Wheelbase structure

A vehicle, comprising:

• an engine configured to be powered by a plurality of energy storage or transformation devices,
• a first axle housed in a first axle housing and a second axle housed in a second axle housing, the first axle and the second axle being separated along a longitudinal direction, and
• a vehicle main supporting structure forming a wheelbase structure, the wheelbase structure rigidly connecting the first axle housing and the second axle housing and comprising:
• at least one longitudinal frame member extending between the first axle and the second axle;
• and
• an outer boundary comprising a top boundary surface, a bottom boundary surface, and a plurality of side boundary surfaces extending between the top boundary surface and the bottom boundary surface, wherein the outer boundary forms an inner housing space bounded by the outer boundary, and wherein the inner housing space is formed as a box, compartment, or container for housing energy storage or transformation devices, with the top boundary surface and the bottom boundary surface being parallel to each other,
• wherein:
• at least a portion of the outer boundary extends in the longitudinal direction along at least a majority of the distance between the first and second axles,
• at least one side boundary surface of the outer boundary comprises a side wall that extends in the longitudinal direction, the side wall being formed by the at least one longitudinal frame member,
• the side wall is formed by a sandwich structure comprising two external layers being outer metal layers and an internal core comprising a foam or insulation layer, wherein one of the external layers faces inwards towards the inner housing space and the other one of the external layers faces away from the inner housing space, and
• the vehicle is devoid of a ladder frame connecting the first axle housing to the second axle housing.