Talk about the safety of car seats - the battle between rigid seats and flexible seats


When people mention car seats, they will think more abo […]

When people mention car seats, they will think more about comfort-related functions: leather seats, N-way electric adjustment, seat heating, massage... but the other one of the seats can be said to be more important. It has always been ignored by consumers, and that is security. Car seats are an important part of the occupant restraint system.
When it comes to the occupant restraint system, everyone will first think of safety belts, airbags and other devices. The car seat was silently crying. Yes, everyone has forgotten that car seats are also an important part of the occupant restraint system. In theory, in the field of passive safety of automobiles, as long as the car is in contact with the occupant, the parts that may be loaded with the human body are considered to be occupant restraints. And when people decide to sit and drive, instead of standing and driving, the seat is already a restraint system, so its qualifications should be considered as a veteran. However, the role of the seat in terms of occupant comfort is too prominent, resulting in safety being ignored by consumers.
In fact, engineers have long noticed the protection of the car seat to the occupants. In the 1960s, people have noticed that in a car crash, the probability of a tail collision is small, but the proportion of damage caused and the cost of medical care are relatively high. In general, when the vehicle is rear-ended, the relative speed is not high, which is a relatively minor collision. Naturally, people tend to design the stiffness of the seat back to be relatively small (herein referred to as the "flexible" design), to minimize the load on the occupant's body during the collision. However, by the early 1980s, everyone had assessed the traffic accident data and found problems. In some serious rear-end collision accidents, such as a small car being arched by a large truck, or the rear car did not slow down at all, the casualties of the occupants were rather fierce. Upon analysis, the engineers found that the previous seats were too soft. Under the violent rear-end collision, the back of the chair was loaded by the impact force of the occupant's backward movement, and after turning backward to an angle of more than 60 degrees with the vertical direction, I can't hold the crew. The occupant will cross the seat in a water-filled posture and "fly" out to the structure at the rear of the car... The consequences can be imagined.
Since the seat is too "soft", then make the structure of the seat harder ("rigid"). The problem is that when the seat stiffness becomes hard, the occupant receives more force from the back of the chair under low-speed collision, and the tendency of the occupant's trunk to move backward is limited by the “hard” seat back, thus aggravating the head and torso. The relative movement between them increases the risk of whiplash in the neck (for whiplash, followed by a special article). Although the rigid seat takes care of the protection requirements of high-speed working conditions, it sacrifices the protection effect of low-speed working conditions.
The controversy about whether the seat is "hard" or "soft" has been going on for nearly 40 years. Until the 1990s, Dr. Viano of General Motors proposed a new seat structure design. Only get a better solution. This type of seat is called "New Generation of Yielding Seats with High Retention" (English: A New Generation of Yielding Seats with High Retention, simple and rudely translated is a new generation of soft and hard seats...) Viano Make drastic changes to the traditional back structure. Its main feature is that the periphery of the seat back is a strong circle structure with a hollow in the middle. The skeleton is to ensure that the seat can withstand a large load when the high-speed tail collides, and the occupant is held to hold; while the "big hole" in the middle allows the low-speed collision, the back of the occupant is trapped. At this point, the occupant only receives the reaction force generated when the backrest foam and the spring structure are squeezed, so it is softer and can reduce the whiplash in the neck. GM has generally assembled such seats in its product line since 1997 and has opened the design to other car manufacturers. In a 2014 paper, Viano pointed out that this type of seat can reduce deadly injuries in tail crashes by 46.3%.

The "rigid" and "flexible" battles of car seats allow us to see the evolution of car seats, the "old" car parts, as traffic conditions and damage theory evolve. Until today, automotive engineers are constantly striving to improve the safety of seats, such as further reducing the risk of whiplash in tail-on collisions; preventing occupant's dive injuries in frontal collisions.

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