Interesting interpretation of five major safety design misunderstandings, breaking the inherent cognition

Because of the internet and automobile media, consumers have a deeper understanding of automobile products, which easily exceeds the sales of 4S stores. You can't find any knowledge, but there are always some misunderstandings about automobile safety in the vast information sources. You've never got the right answer, and some of them are getting worse. Today, let's correct some inherent mistakes.

1. The main function of the resin protective device of the chassis is not to prevent collision.

Kelin 03 chassis is completely covered with resin fender, and the chassis is very flat, with good aerodynamic optimization performance. When the guard is removed, you can see that the body-in-white is sprayed with anti-corrosion coating. What we want to say is that the primary function of the chassis resin guard is to optimize the air flow direction and reduce the wind noise during driving. The flatter the chassis, the less noise it produces, which indirectly reduces fuel consumption.

The resin fender not only optimizes the aerodynamics, but also plays a role in chassis protection, which plays a certain role when encountering foreign objects while driving, but this is not the original intention of the design. If there is a bottoming accident, the probability of damage to the resin guard plate is still relatively large. The chassis of a car like Linke 03 is sprayed with coating, which is an anti-corrosion and anti-collision design. Plus the resin guard outside, it is double protection.

2. Panoramic skylight does not mean that the roof must have a reinforced structure.

Let's take Kline 03 as an example. Its roof is not specially designed to strengthen the metal structure, nor is it covered with any sound insulation cotton, and there are no auxiliary reinforcements around the frame. Only a thin reinforcing rib is designed at the rear of the whole roof, and two asphalt shock-proof patches are attached to the last side.

Panoramic skylight doesn't provide the reinforcing frame of the roof, which obviously saves a certain cost, and there is nothing to discuss in depth. Of course, in vehicle accidents, the roof is not the majority, which has become a place where some manufacturers cut corners.

Let's look at a positive example: BYD Song MAX.

BYD Song MAX adopts a super-large "canopy" design, and the huge skylight makes us have great doubts about the strength of its roof structure. When the interior trim panel is disassembled, we can see the reinforcing plate above the A-pillar and the reinforcing rib above the D-pillar, as well as the frame reinforcing steel plate structure on both sides of the roof, which makes our doubts disappear.

3. The amount of anti-vibration paste or anti-vibration glue is not as much as possible.

A large piece of regenerated cotton soundproof pad was laid under the back seat of Link 03. After being removed, you can see that almost all the body-in-white is covered with sheet metal glue, which plays the role of sound insulation and shock prevention. Such a large area is really rare, and the harmful gas emitted by glue takes a long time to volatilize. Careful observation shows that there are many cracks in the sheet metal adhesive, which further expands the area of harmful gas emission sources.

In fact, this method of using sheet metal glue to make shock-proof stickers is rare, but it can reduce the cost. However, no matter what material, large-scale fitting is not a good thing. From the design point of view, this last resort will only be used when the original design of the body-in-white can't eliminate the vibration. It indirectly reflects that the design is not mature enough. So it doesn't mean that it is a good thing to use materials that seem to cost money.

4. The integrated stamping process door is only better in appearance, not stronger.

WEY？ VV5 doors are all integrally stamped and formed, and the overall toughness is better than that of the door with splicing technology, and the possibility of rust of solder joints is also avoided. But this does not mean that integral stamping is more durable than splicing. Indeed, because the metal material of the door panel is a whole, its tensile and torsional properties are better. However, in the case of perfect welding technology, the firmness of the spliced door is no less than that of integrated stamping, which is a misleading disaster area reported by the media for a long time.

5, ordinary spot welding process is not lower than the laser welding strength.

This is similar to the above, mainly on the door frame and on both sides of the roof. Laser welding has advanced technology, high cost, high degree of automation and beautiful appearance. The traditional spot welding technology is mature, low cost and poor aesthetics. Theoretically speaking, there is no substantial difference in the quality of splicing connection between the two under the condition of meeting the relevant standards.

Just from the appearance, spot welding is sparse, while laser welding is a whole weld. However, in the internal structure, the steel plates connected by spot welding process also need to be glued internally. This is a kind of welding glue, which plays a role in enhancing adhesion, and the final effect is not lost to laser welding.

The picture above shows the door frame welded by laser. There is an inconspicuous weld after painting, which is very beautiful.

Summary: What's going on? Do you feel that sometimes some opinions persist for many years, but they are not correct? The theory that Japanese cars are thin and unsafe is still directly popular. We feel that we still need to look at the problem from a scientific perspective in order to get a correct understanding.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.