The front and rear ends of the car are equipped with bumpers, which not only have decorative functions, but also are safety devices that absorb and mitigate external impact forces, protect the body and protect the body and occupant safety functions.
Many years ago, the front and rear bumpers of the car were mainly made of metal materials, and were punched into U-shaped channel steel with a thickness of 3 mm or more. The surface was treated with chrome plating and riveted or welded with the frame rails. The large gap, as if it were an attached part, looks very unattractive.
With the development of the automotive industry and the extensive application of engineering plastics in the automotive industry, automotive bumpers have also entered the path of innovation as an important safety device. At present, in addition to maintaining the original protection function, the front and rear bumpers of the car must pursue harmony and unity with the shape of the car body, and pursue its own lightweight. The front and rear bumpers of the car are made of plastic and are known as plastic bumpers.
The outer plate and the cushioning material are made of plastic, and the beam is stamped into a U-shaped groove by a cold-rolled sheet having a thickness of about 1.5 mm; the outer plate and the cushioning material are attached to the beam, and the beam is screwed to the frame longitudinal beam, and can be attached at any time. Remove it. Plastics used in such plastic bumpers are generally made of two types, polyester and polypropylene, and are injection molded. For example, the bumper of the Peugeot 405 sedan is made of a polyester-based material and is formed by a reaction injection molding method. The bumpers of Volkswagen's Audi 100, Golf, Santana in Shanghai, and Xiali in Tianjin are made of polypropylene-based materials by injection molding. There is also a kind of plastic called polycarbonate in foreign countries. It is infiltrated into the alloy composition and is alloy injection molding. The processed bumper not only has high strength rigidity, but also has the advantage of being weldable, and the coating performance is good. The use of cars is increasing.
The geometry of the bumper must be considered in accordance with the shape of the vehicle, to ensure the appearance, but also to meet the mechanical characteristics and energy absorption characteristics to ensure the vibration absorption and slowness during impact.