Most of the frames used in early cars were made of cage-like steel beams and columns, that is, on two parallel main beams, they were made by adding many auxiliary beams connected to the left and right in a step-like manner. . The car body is built on the frame. As for the door, sand board, hood, luggage compartment cover and other sheet parts, they are additionally covered outside the car body, so the car body and the frame are actually two independent structure. The biggest advantage of this design is that it can take into account both light weight and rigidity, so it has been favored by many sports car manufacturers. Early Ferrari and Lamborghini all adopted this design.
Because the steel frame design must connect the main beam and the auxiliary beam through many joints, and the cage structure cannot make a large space, it is not suitable for use except for the complicated manufacturing and not conducive to mass production. In a four-door RV that emphasizes the sense of space. Therefore, the single-structure frame has gradually become the mainstream in the car world, and the cage-shaped steel frame has gradually been replaced by this single frame that combines the body and the frame (such as: container truck ), the single frame is generally called "chassis", which is derived from the English "Platform".
3 Frame classification
At present, the frame is divided into a trapezoidal frame, a spine frame, a peripheral frame and a truss frame according to different structural forms.