The inner door guard assembly is also an important part of the car interior, including left front and left rear door guards, right front and right rear door guards, on top of which there are also some functional parts assemblies, such as inner grommets, armrest trims, map pockets, glass lift switches and speaker covers. The inner door guard is powerful and should not be underestimated. It not only plays a role in decorating the car cabin, but also provides a support point for the rider's elbow, which improves the riding comfort, so that the rider can quickly find a suitable sitting position and have a better riding experience. In addition, the inner door guard can cover the door sheet metal, so that the door switch convenient, sound insulation and noise reduction, moisture and water resistance, collision can be deformed to absorb energy, maximize the protection of the car personnel's life safety.
The main materials used for door guards are PP and ABS, which is a high-strength plastic called acrylonitrile-butadiene-styrene copolymer (ABS). Because this type of plastic has the characteristics of lightweight, impact resistance, abrasion and corrosion resistance, easy processing and molding, so it is commonly promoted to the door guards, through the injection molding process to mass production.
Door guard classification is relatively complex, different dimensions have different division methods, can be divided according to their own structure and function, but also according to the grade of the model division, combined with a variety of factors can be divided into simple door guards and complex door guards.
Simple door guard is composed of door guard body, trim plate and many functional parts mentioned above, which is made of PP and ABS sheet through injection molding process. The structure of this type of door guard is simple, the appearance of the body is mostly a large plane straight up and down, without too much concave and convex modeling, so the manufacturing process is simple and the production cost is low, so it is more common on the market, usually used in economic vehicles, trucks and buses.
Complex door guards mainly include interior parts such as upper door guard body, lower door guard body, door lamps, wooden or plastic decorative strips and cushion energy-absorbing blocks. The classification of the upper door guard body and instrument panel classification is largely the same, generally divided into hard upper door guard and soft upper door guard. Hard door guard is injection molding processing molding, while the soft door guard is divided into three layers. The most inside is the skeleton, the middle layer is the foam layer, the most outside is the skin layer. Skin fabrics generally have knitted, imitation leather and leather three kinds of skin process can be used hand wrapped process, medium and high-end cars are generally used in plastic-lined skin process.
As automotive safety is increasingly emphasized by consumers, the role of interior protection for occupants is also gradually improved. According to the requirements of the collision regulations, the inner door guards need to play the role of full deformation and energy absorption to protect the lives of the occupants in the event of a collision. Therefore, a foam energy-absorbing block will be designed and installed on the lower right side of the inner door guard. Nowadays, the common foam energy-absorbing block is usually made of polypropylene foam resin, polypropylene and polyurethane foam molding.
There is another important module in the interior assembly, which is the vehicle side trim guard assembly. It mainly includes A-pillar upper and lower guards, B-pillar upper and lower guards, C-pillar upper and lower guards and rear side panels, SUV models also added D-pillar guards. The function of the side trim panel is the same as that of the door panel, which mainly prevents the sheet metal from being exposed, improves the overall aesthetics of the interior, and provides proper energy absorption in the event of a collision. Side trim panels are generally made of PP and PPO plastic, PPO plastic, also known as polyphenylene ether, is a comprehensive performance of good engineering plastics. Because of its wear-resistant, corrosion-resistant, non-toxic and flame-retardant properties, PPO plastic is widely used in the automotive industry. However, considering the material cost, most of the side trim panels are still mass-produced with PP plastic, which has a better price advantage.