Honda Motor Co Ltd employed a floor carpet with an enhanced sound absorbing effect to improve silence in the interior space of the new "Freed" compact minivan, which was released Sept 16, 2016.
The floor carpet of the previous model is made by forming foamed urethane resin into a sheet-like base material and, then, compressing the base material so that it fits the shape of the floor panel made of steel plate.
The thickness of the base material after the compression is not even, and there are thick areas and thin areas. In the thin areas, air bubbles are crushed, diminishing air layers and lowering sound absorbing effect.
To solve such problems, the base material of the new model's floor carpet is formed as a single part by using foamed urethane resin, and the thickness of the base material fits the shape of the floor panel. As a result, air bubbles in the thin areas of the base material are not crushed, making air layers larger than those of the previous model's base material.
"It has a noise reduction effect of up to 5dB though it depends on frequency," Honda said.
Also, for the base material of the previous model, two manufacturing processes are required to (1) form foamed urethane resin into a sheet and (2) compressing it. On the other hand, the base material of the new model requires only one manufacturing process. As a result, the total cost of the new model's base material is the same as that of the previous model's base material, Honda said.