Noise insulation structure

#The present invention relates to an improvement in a noise insulation structure for a vehicle floor section.

#Noises reflected from road surfaces and noises radiated from an exhaust system are transmitted through a steel floor panel into a vehicle compartment. It is desirable that such transmission noises are as small as possible for comfort of a vehicle occupant. To this end, various attempts have heretofore been made in the past to take a variety of noise insulation measures for a floor-placed carpet (see Japanese Patent Publication No. 6-2988).

#FIGS. 3A to 3C hereof illustrates a prior art noise insulation structure for a vehicle floor section.

#The present invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which:

#FIGS. 1A to 1C are schematic views illustrating a noise insulation structure for a vehicle floor section of an embodiment according to the present invention, FIG. 1B being an enlarged cross sectional view of a portion b of FIG. 1A, and FIG. 1C being an elastic modeling representation of FIG. 1B;

#FIG. 2 is a graph showing a noise insulation performance curve obtained with the noise insulation structure of a two-way freedom system according to the present invention;

#The following description is merely exemplary in nature and is in no way intended to limit the invention, its application or uses.

#Referring to FIG. 1A, a vehicle body 11 has a floor b with a noise insulation structure.

#As shown in FIG. 1B, the noise insulation structure according to the present invention includes a floor plate 12 made of steel, on which a urethane layer 13, having an adhesive property with respect to the floor plate 12, is placed, whereupon a fibrous layer 15, made of fibrous material having a lower Structure Youngs Modulus than that of urethane, is placed on the urethane layer 13 via a lower mass layer 14 and a carpet 17 is placed on the fibrous layer 15 via an upper mass layer 16.