TS Tech Co Ltd exhibited a next-generation auto seat with a high safety against crashes at the 42nd Tokyo Motor Show 2011.
This time, the company realized both a high safety and a low weight by removing the active head rest used for its existing products and improving the shock-absorbing function of the seat's frame.
For the next-generation seat, TS Tech enhanced the shock-absorbing capability of the back rest's frame and employed a head rest whose amount of deflection is small. It was designed based on the concept that impacts caused by crashes are absorbed mainly by the frame.
Traditional active head rests support drivers' and passengers' heads by using impact forces applied to their frames to push the head rests forward. Though they have a high safety against crashes, they need a mechanism to transmit a force. And the mechanism increases their weights.
In recent years, there are demands for lighter auto seats from the perspectives of improving fuel efficiency and reducing the emissions of greenhouse gases. Therefore, TS Tech stopped using active head rests and decided to improve the shock-absorbing capability of frames.
Specifically, the lower part of the back rest's frame has a cutout shape so that stress is concentrated on the part. As a result, the frame deforms as if it crashes the cutout shape and absorbs the shock.
In addition, the back rest is equipped with a spring whose strength is adjusted so that the driver or passenger sinks into the seat only at the time of impact. The frame using this spring was employed for Honda Motor Co Ltd's Civic and CR-V.
The rigidity of the head rest was improved by changing the method to weld it to the back rest's frame. The back rest's frame has a shape of a round pipe. Therefore, for the existing products, TS Tech presses part of the pipe into a flat shape and welds the head rest on that part.
However, the rigidity of the frame lowers when it is flattened. To solve this problem, TS Tech adds a plate-like attachment to the back rest's frame and welds a joining part (guide stay) for the head rest to the attachment.
As a result, it became possible to ensure a rigidity higher than those of the existing products and reduce the amount of deflection. Though the use of the attachment increases mass, the new seat is lighter than a seat using an active head rest, the company said.
The next-generation seat was designed to support most of the vehicle classes. And TS Tech plans to promote the seat to automakers as a "standard seat."