Structural element of an assembly kit

A structural element of an assembly kit for mounting to a supporting plate provided with holes each having a predetermined transverse dimension, a drive unit including a motor and a transmission located adjacent to one another in a first direction, and a plurality of wheel axles spaced from each other in the first direction, the structural element comprising a body portion having an inner hollow arranged for receiving a motor therein, and side walls spaced from one another in a second direction which is transverse to the first direction, said body portion having an inner surface facing toward said inner hollow and an outer surface facing away from the same;

• a plurality of projections on said outer surface of said body portion and each arranged to extend through a respective one of the holes of the supporting plate, at least one of said projections having an outer end portion extending outwardly beyond the supporting plate said outer end portion having a transverse dimension exceeding said predetermined dimension;
• a tightening member located outwardly beyond the supporting plate and engaging said outer portion of said one projection so as to tighten said body portion to the supporting plate;
• and at least three connecting elements on said outer surface in each of said side walls of said body portion, extending parallel to each other and being spaced from each other in said first direction so as to connect wheel axles to said body portion at locations spaced in said first direction, whereby the drive unit can be connected to the supporting plate even in the central region thereof, and toy vehicles may be constructed with different distances between axles, including a distance which is smaller than the length of the drive unit.