on the plane vertical to this axis.
In the embodiment in which the main frame includes of two lateral hollow profiles and two torsion spring tubes configured as a roughly ring-shaped, flexure- and torsion-resistant arrangement, it is possible to achieve optimal flexural and torsion stiffness for the main frame.
In a further embodiment, the connection between the lateral hollow profiles and the torsion spring tubes or other connecting profiles is achieved by preferably flat gusset plates arranged on both sides of the lateral hollow profile. Thus, a torsion-resistant connection of the hollow profiles is achieved by the special arrangement of the gusset plates on both sides of the profile. The gusset plates are necessary in order to connect at least two profiles with any connecting angle with each other rigidlydirection of travel. Therefore, the oscillating levers should advantageously be designed so as to have low torsion resistance along the longitudinal axis, in order to be able to achieve the necessary axle compression. This may be achieved with a thin-walled, flat design of the oscillating levers. Lateral forces such as those acting on the vehicle with every change in direction would cause an inadmissible deformation of the oscillating levers crosswise to the direction of travel.
Thereby, an embodiment in which the rotation point of the oscillating lever lies on the front connecting pin facing in the direction of travel, on the line of efficacy between the overall center of gravity of the vehicle and the contact point of the wheels proves advantageous, since with the arrangement along this line