Noise absorbing structure and noise absorbing/insulating structure

Abstract

A noise absorbing structure for effectively absorbing noise in a wide frequency range includes a first noise absorbing portion that is hollow and includes one or more first holes. The structure further includes a second noise absorbing portion that is hollow and includes one or more second holes. The total area of the one or more first holes differs from the total area of the one or more second holes.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a noise absorbing structure and a noise absorbing/insulating structure for absorbing noise, and more particularly, to a noise absorbing structure and a noise absorbing/insulating structure for absorbing noise in the passenger compartment of a vehicle.

In recent years, there has been an increasing demand for quietness in the passenger compartment of a vehicle. Accordingly, it is required that noise be further reduced in the passenger compartment. As a measure for reducing the noise, there has been proposed a noise absorbing structure, which includes a base with a plurality of holes (noise absorbing wall) and a space provided at the back of the base. This type of noise absorbing structure exhibits its noise absorbing effect based on the Helmholtz resonance principle when noise generated by a noise source passes through the holes formed in the noise absorbing wall. The sonic energy is absorbed rapidly by this noise absorbing effect.

Japanese Laid-Open Utility Model Publication No. 2-115049 describes an example of a vehicle ceiling that absorbs noise. The vehicle ceiling is provided with a hollow member. Further, a plurality of holes (noise absorbing holes) for air-column resonance reduction is formed on the passenger compartment side of a base. With this vehicle ceiling, the noise in the passenger compartment is guided through the holes into an air layer within the hollow member and reduced therein.

Japanese Laid-Open Patent Publication No. 2000-16189 describes a rear shelf trim for absorbing noise. The rear shelf trim is provided with a hollow member having an upper wall. Additionally, a plurality of holes is formed in the upper wall. The total area of the holes corresponds to about 20 to 50% of the area of the upper wall having these holes. With this rear shelf trim, the noise in the passenger compartment is also guided through the holes into the hollow space within the hollow member and absorbed therein.

Japanese Laid-Open Patent Publication No. 5-92441 describes a noise-insulating board having cylindrical hollow bodies arranged in a concentrated manner on a support board. The distal end of the cylindrical hollow body is open.

Further, as one of other noise reduction measures, felt or THINSULATE is applied to the rear face of a console box. The noise generated from the engine and gears is absorbed and reduced by the felt or THINSULATE.

In the above-described vehicle ceiling and rear shelf trim of the prior art, the holes all have an identical diameter. That is, the openings have an identical area. Accordingly, the frequency range of the noise absorbed by these holes is limited to a narrow range. Also, as for the noise-insulating board described above, since it is difficult to enlarge the volume of space in the cylindrical hollow bodies, the noise absorbing effect based on the Helmholtz resonance principle cannot be exhibited sufficiently. Consequently, the conventional noise absorbing mechanisms still need improvement, particularly in terms of absorbing the interior noise in a wide frequency range.

SUMMARY OF THE INVENTION

The present invention provides a noise absorbing structure and a noise absorbing/insulating structure capable of effectively absorbing noise in a wide frequency range.

One aspect of the present invention is a noise absorbing structure for absorbing noise. The structure is provided with a first noise absorbing portion that is hollow and includes one or more first holes, and a second noise absorbing portion that is hollow and includes one or more second holes. The one or more first holes has a total area different from that of the one or more second holes.

Another aspect of the present invention is a noise absorbing/insulating body for absorbing and insulating noise. The body is provided with a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall. The body is further provided with a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall. The one or more first holes has a total area different from that of the one or more second holes.

A further aspect of the present invention is a noise absorbing structure for absorbing noise. The structure is provided with a first sub-box that is hollow and includes one or more first holes, and a second sub-box that is hollow, includes one or more second holes, and has the same shape as the first sub-box. The one or more first holes has a total area different from that of the one or more second holes.

Another aspect of the present invention is a noise absorbing structure for absorbing noise. The structure is provided with a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes. The structure is further provided with a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes. The first noise absorbing portion and the second noise absorbing portion each have a volume that is different from one another.

A further aspect of the present invention is a noise absorbing/insulating structure for absorbing and insulating noise. The structure is provided with a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall. The structure is further provided with a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall. The first noise absorbing portion and the second noise absorbing portion each include a volume that is different from one another.

Another aspect of the present invention is a noise absorbing structure for absorbing noise. The structure is provided with a first sub-box that is hollow and includes one or more first holes, and a second sub-box that is hollow and includes one or more second holes having the same shape as the first holes. The one or more first holes has a total area and the one or more second holes has a total area that is the same as the total area of the one or more first holes. The first sub-box and the second sub-box each have a volume that is different from one another.

Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a perspective view showing a passenger compartment in which a noise absorbing/insulating box according to a first embodiment of the present invention is installed;

FIG. 2 is a horizontal cross-sectional view of the console showing the position where the noise absorbing/insulating box of FIG. 1 is installed;

FIG. 3 is a vertical cross-sectional view of the console showing the position where the noise absorbing/insulating box of FIG. 1 is installed;

FIG. 4 is a perspective view showing the noise absorbing/insulating box of FIG. 1;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a perspective view showing a noise absorbing/insulating box according to a second embodiment of the present invention;

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is a horizontal cross-sectional view of a console showing the position where a noise absorbing/insulating box according to a third embodiment of the present invention is installed;

FIG. 9 is a vertical cross-sectional view of the console showing the position where the noise absorbing/insulating box of FIG. 8 is installed;

FIG. 10 is a perspective view showing the noise absorbing/insulating box of FIG. 8;

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a perspective view showing a noise absorbing/insulating box according to a fourth embodiment of the present invention;

FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12;

FIG. 14 is a perspective view showing a noise absorbing/insulating box according to a fifth embodiment of the present invention;

FIG. 15 is a cross-sectional view taken along line 15-15 of FIG. 14;

FIG. 16 is a perspective view showing a console box in which a noise absorbing/insulating box according to a sixth embodiment of the present invention is installed;

FIG. 17 is a partial cross-sectional view showing the console box of FIG. 16;

FIG. 18 is a schematic view showing a glove compartment in which a noise absorbing/insulating box according to a seventh embodiment of the present invention is installed;

FIG. 19 is a cross-sectional view showing the glove compartment of FIG. 18;

FIG. 20 is a schematic view showing a glove compartment in which a noise absorbing/insulating box according to an eighth embodiment of the present invention is installed; and

FIGS. 21A and 21B are perspective views showing further examples of the noise absorbing/insulating box.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the drawings, like numerals are used for like elements throughout.

First Embodiment

A first embodiment of a noise absorbing/insulating structure according to the present invention will now be described with reference to FIG. 1 through FIG. 5. The noise absorbing/insulating structure of the first embodiment is installed in a console 111, which is an interior equipment of a vehicle.

As shown in FIG. 1, the console 111 is arranged between the driver's seat and passenger seat in the passenger compartment. Drive train components (not shown) including the engine and gears are mounted in the front lower part of the vehicle. Various kinds of noise, generated by the drive train components, are propagated through the inner space of the console 111 and leak into the passenger compartment through gaps thereby creating the noise in the passenger compartment. Two noise absorbing/insulating boxes 112 are installed inside the console 111 as noise absorbing bodies for reducing the passenger compartment noise. The two noise absorbing/insulating boxes 112 form a noise absorbing/insulating structure.

In the console 111, as shown in FIG. 2, attachment portions 114 are defined on the inner faces of opposing side walls 111a. A noise absorbing/insulating box 112 is attached to each attachment portion 114. The attachment portions 114 each have a pair of guide walls 115 projecting towards the inside of the console 111. A guide groove 116 is formed between the pair of guide walls 115. These attachment portions 114 are located at front and rear parts of the console 111 at positions corresponding to where the noise absorbing/insulating boxes 112 are to be installed. The lateral sides of each noise absorbing/insulating box 112 are inserted in the guide grooves 116 of the corresponding attachment portion 114. This fixes the noise absorbing/insulating boxes 112 at predetermined positions in the console 111.

The noise absorbing/insulating boxes 112 each have a substantially rectangular box shape and are formed by blow molding or injection molding synthetic resin, such as polypropylene (PP), polyethylene (PE), or acrylonitrile-butadiene copolymer (ABS). The noise absorbing/insulating box 112 has a first wall 121, a second wall 122 opposing the first wall 121, and four side walls 124, which link the first wall 121 and the second wall 122. In other words, the noise absorbing/insulating box 112 is a hollow structure and is provided with a space 123 therein. The first wall 121 is provided with a plurality of circular holes 128, which communicate the space in the console 111 with the space 123 in the noise absorbing/insulating box 112. No holes are formed in the second wall 122 or the side walls 124 so that the second wall 122 and side walls 124 block the space 123 in the noise absorbing/insulating box 112 from the space in the console 111.

The noise absorbing/insulating boxes 112 held by the attachment portions 114 are arranged with their respective first walls 121 facing the front side of the vehicle. One of the noise absorbing/insulating boxes 112 is arranged in a front part of the console 1111 and the other one is in a rear part of the console 111 so as to block the path of noise propagated in the console 111. As shown in FIG. 3, the heights of these two noise absorbing/insulating boxes 112 are determined according to the height of the console 111. The lateral sides and upper and lower sides of the noise absorbing/insulating boxes 112, which are held by the attachment portions 114, abut against the inner walls of the console 111. This means that the noise absorbing/insulating boxes 112 are arranged such that no gap is formed between the noise absorbing/insulating boxes 112 and the inner walls of the console 111. Consequently, the noise absorbing/insulating boxes 112 prevent engine noise or gear noise generated by the drive train components from leaking into the passenger compartment and creating noise in the passenger compartment.

In each of the noise absorbing/insulating boxes 112, air in the holes 128 of the first wall 121 acts as a mass when noise propagated from the front side of the vehicle passes through the holes 128 in the console 111. Aside from the air in the holes 128 of the first wall 121, air in the space 123 of the noise absorbing/insulating box 112 isolated by the second wall 122 and the side walls 124 from the space in the console 111 acts as a spring. The air in the holes 128 is vibrated acutely by the interaction of the mass (air in the holes 128) with the spring (air in the space 123) to convert sonic energy into thermal energy. This rapidly reduces noise. The noise absorbing/insulating box 112 exhibits its noise absorbing capability in this manner and rapidly absorbs the noise generated by a noise source.

Next, the principal parts of the present invention will be described. FIG. 4 is a general perspective view of the noise absorbing/insulating box 112, and FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4. The two noise absorbing/insulating boxes 112 located at the front and rear parts of the console 111, respectively, have an identical configuration.

As shown in FIGS. 4 and 5, the noise absorbing/insulating box 112 has a first noise absorbing portion 126a and a second noise absorbing portion 126b, which are hollow and partitioned by a partition wall 125 that connects the first wall 121 and the second wall 122. In other words, the noise absorbing/insulating box 112 of the first embodiment is formed by integrating the first noise absorbing portion 126a, which has a rectangular box shape, with the second noise absorbing portion 126b, which also has a rectangular box shape. The first noise absorbing portion 126a is defined by parts of the first wall 121 and the second wall 122, the side walls 124 and the partition wall 125. The second noise absorbing portion 126b is defined by other parts of the first wall 121 and the second wall 122, the side walls 124 and the partition wall 125. The partition wall 125 divides the space 123 in the noise absorbing/insulating box 112 into two sub-spaces 123a and 123b. The sub-space 123a in the first noise absorbing portion 126a has the same volume as the sub-space 123b in the second noise absorbing portion 126b.

The part of the first wall 121 forming the first noise absorbing portion 126a is defined as a first noise absorbing wall 121a. The part of the second wall 122 forming the first noise absorbing portion 126a and facing towards the first noise absorbing wall 121a is defined as a first noise insulating wall 122a. The other part of the first wall 121 forming the second noise absorbing portion 126b is defined as a second noise absorbing wall 121b. The other part of the second wall 122 forming the second noise absorbing portion 126b and facing towards the second noise absorbing wall 121b is defined as a second noise insulating wall 122b.

A plurality of holes 128 are formed in the first noise absorbing wall 121a at equal intervals in the longitudinal and lateral directions of the first noise absorbing wall 121a. A plurality of holes 128 are formed in the second noise absorbing wall 121b at equal intervals in the longitudinal and lateral directions of the second noise absorbing wall 121b. The group of the plurality of holes 128 formed in the first noise absorbing wall 121a constitutes a first noise absorbing hole group 120a. The group of the plurality of holes 128 formed in the second noise absorbing wall 121b constitutes a second noise absorbing hole group 120b.

The holes 128 constituting the first noise absorbing hole group 120a have an identical diameter and identical opening area. The holes 128 constituting the second noise absorbing hole group 120b also have an identical diameter and an identical opening area. The holes 128 constituting the second noise absorbing hole group 120b have a larger diameter, and hence a larger opening area, than the holes 128 constituting the first noise absorbing hole group 120a. Accordingly, the opening area S1 of the first noise absorbing hole group 120a, which is the total sum of the opening areas of the holes 128 in the first noise absorbing wall 121a, differs from the opening area S2 of the second noise absorbing hole group 120b, which is the total sum of the opening areas of the holes 128 in the second noise absorbing wall 121b. In the first embodiment, the opening area S2 of the second noise absorbing hole group 120b is larger than the opening area S1 of the first noise absorbing hole group 120a.

As described above, the noise absorbing/insulating box 112 exhibits its noise absorbing capability as the result of air in the holes 128 acting as a mass and air in the space 123 acting as a spring. In a similar manner, the first and second noise absorbing portions 126a and 126b exhibit their noise absorbing capability as the result of air in the first and second noise absorbing hole groups 120a and 120b acting as a mass and air in the sub-spaces 123a and 123b of the first and second noise absorbing portion 126a and 126b acting as a spring.

Since the sub-spaces 123a and 123b have the same volume, air in the sub-spaces 123a and 123b act as springs that act in the same manner. In contrast, since the opening area S1 of the first absorbing hole group 120 differs from the opening area S2 of the second noise absorbing hole group 120b, the mass of the air in the first noise absorbing hole group 120a differs from that of the air in the second noise absorbing hole group 120b. Since the masses acting in the first and second noise absorbing portions 126a and 126b differ from each other, the frequency ranges of the noise absorbed in the first and second noise absorbing portion 126a and 126b differ from each other. Accordingly, the noise absorbing/insulating box 112 is capable of absorbing a wide range of noise including the frequency range absorbed by the first noise absorbing portion 126a and the frequency range absorbed by the second noise absorbing portion 126b.

The opening areas S1 and S2 of the first and second noise absorbing hole groups 120a and 120b are determined as required according to the frequency range of noise to be absorbed by the noise absorbing/insulating box 112, or the frequency range of noise generated by the noise source. Additionally, the first and second noise insulating walls 122a and 122b that do not have the first and second noise absorbing hole groups 120a and 120b are arranged to block the noise propagated in the console 111 from the front side of the vehicle. Consequently, the noise absorbing/insulating box 112 has a noise insulating capability for insulating noise in addition to the noise absorbing capability for absorbing noise generated by a noise source.

The noise absorbing/insulating box 112 of the first embodiment has the advantages described below.

The noise absorbing/insulating box 112 is designed such that the opening area S1 of the first noise absorbing hole group 120a of the first noise absorbing portion 126a differs from the opening area S2 of the second noise absorbing hole group 120b of the second noise absorbing portion 126b. As a result, when various types of noise in a wide frequency range pass through the first and second noise absorbing hole groups 120a and 120b, the noise absorbing effect based on the Helmholtz resonance principle is exhibited, and the noise is rapidly absorbed by the noise absorbing/insulating box 112. Therefore, the noise absorbing/insulating box 112 absorbs noise in a wider frequency range than the conventional techniques. That is, the noise absorbing/insulating box 112 exhibits a favorable noise absorbing capability with respect to noise in a wide frequency range. Accordingly, with the noise absorbing/insulating box 112 of the first embodiment, noise such as that of the engine and the gears in the drive train is further reduced compared to the prior art. This achieves improved quietness in the passenger compartment.

In the first and second noise absorbing portions 126a and 126b, all of the plurality of holes 128 constituting the first noise absorbing hole group 120a have an identical diameter and identical opening area, and all of the plurality of holes 128 constituting the second noise absorbing hole group 120b also have an identical diameter and an identical opening area. In the noise absorbing/insulating box 112, the frequency ranges of the noises absorbed by the first and second noise absorbing portions 126a and 126b may be determined separately and explicitly.

The noise absorbing/insulating box 112 includes the first and second noise insulating walls 122a and 122b opposing the first and second noise absorbing walls 121a and 121b, respectively. The first and second noise insulating walls 122a and 122b have no holes 128 and separate the space 123 in the noise absorbing/insulating box 112 from the outside. Therefore, the first and second noise insulating walls 122a and 122b block the noise that is propagated through air and inhibits noise generated by a noise source from leaking outside. Accordingly, the noise absorbing/insulating box 112 exhibits excellent noise absorbing/insulating capability with respect to noise in a wide frequency range.

In the noise absorbing/insulating box 112, the first and second noise absorbing portions 126a and 126b have an identical volume, while the opening areas S1 and S2 of the first and second noise absorbing hole groups 120a and 120b of the first and second noise absorbing portions 126a and 126b differ from each other. When the noise absorbing/insulating box 112 is constructed in this manner, the range of the noise absorbed by the noise absorbing/insulating box 112 is varied easily by changing only the first wall 121 having the holes 128. Therefore, the configuration of the noise absorbing/insulating box 112 may easily be modified in correspondence with the frequency range of the noise that is to be absorbed. The noise absorbing/insulating box 112 may thus be used for many purposes.

The noise absorbing/insulating box 112 is thin and has a rectangular box shape and, therefore, occupies a relatively small volume. Accordingly, it is easy to ensure space for installing the noise absorbing/insulating box 112 even in a limited space within vehicle interior equipment such as the console 111.

Two noise absorbing/insulating boxes 112 are arranged in the interior of the console 111 so as to block the path of noise generated by the drive train components and propagated in the console 111. The positions where the noise absorbing/insulating boxes 112 are arranged are optimal for absorbing noise generated by the noise source and for insulating noise generated by the noise source. Thus, the noise generated by the drive train components are absorbed and insulated effectively by installing the two noise absorbing/insulating boxes 112 in these positions.

Second Embodiment

Hereafter, a noise absorbing/insulating box 132 according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view of the noise absorbing/insulating box 132, and FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6.

As shown in FIG. 6 and FIG. 7, the noise absorbing/insulating box 132 includes first and second noise absorbing/insulating sub-boxes 132a and 132b, which are assembled integrally with each other. The volumes in the first and second noise absorbing/insulating sub-boxes 132a and 132b are the same. The noise absorbing/insulating box 132 is thin and has a rectangular box shape formed by joining the side of the first noise absorbing/insulating sub-box 132a with the side of the second noise absorbing/insulating sub-box 132b.

In the noise absorbing/insulating box 132 of the second embodiment, the first noise absorbing/insulating sub-box 132a is constructed as a first noise absorbing portion 146a and the second noise absorbing/insulating sub-box 132b is constructed as a second noise absorbing portion 146b. Specifically, the first noise absorbing/insulating sub-box 132a has a first noise absorbing wall 141a and a first noise insulating wall 142a facing towards the first noise absorbing wall 141a. The first noise absorbing wall 141a has a plurality of holes 148 formed at equal intervals in the longitudinal and lateral directions of the first noise absorbing wall 141a. A group of the holes 148 formed in the first noise absorbing wall 141a constitutes a first noise absorbing hole group 140a.

The second noise absorbing/insulating sub-box 132b has a second noise absorbing wall 141b and a second noise insulating wall 142b facing towards the second noise absorbing wall 141b. The second noise absorbing wall 141b has a plurality of holes 149 having a larger diameter than the holes 148 of the first noise absorbing hole group 140a. The holes 149 are formed at equal intervals in the longitudinal and lateral directions of the second noise absorbing wall 141b. A group of the holes 149 formed in the second noise absorbing wall 141b constitutes a second noise absorbing hole group 140b.

In the second embodiment, like in the first embodiment, the first and second noise absorbing portions 146a and 146b have the same volume, while the opening area S1 of the first noise absorbing hole group 140a differs from the opening area S2 of the second noise absorbing hole group 140b. Accordingly, the noise absorbing/insulating box 132 is capable of absorbing a wide range of noise.

Consequently, the noise absorbing/insulating box 132 of the second embodiment has the advantages described below.

The noise absorbing/insulating box 132 is formed by assembling the first noise absorbing/insulating sub-box 132a having the first noise absorbing hole group 140a integrally with the second noise absorbing/insulating sub-box 132b having the second noise absorbing hole group 140b. The noise absorbing/insulating box 132 exhibits further a preferable noise absorbing capability in a wide frequency range by optimizing the combination of various noise absorbing/insulating sub-boxes designed to absorb noise in various frequency areas.

Third Embodiment

A noise absorbing/insulating box 212 according to a third embodiment of the present invention will now be described with reference to FIGS. 8 to 11. In the third embodiment, the noise absorbing/insulating box 212 has a step-like shape as shown in FIG. 10 and is installed in a console 111 as shown in FIGS. 8 and 9.

As shown in FIGS. 10 and 11, the noise absorbing/insulating box 212 has a first noise absorbing portion 226a, a second noise absorbing portion 226b, and a third noise absorbing portion 226c, which are hollow and are partitioned from each other by first and second partition walls 225a and 225b that link a first wall 221 and a second wall 222. In other words, the noise absorbing/insulating box 212 of the third embodiment is constituted by integrating the first, second, and third noise absorbing portions 226a, 226b, and 226c, each of which has a rectangular box shape. The first wall 221 is formed to have a step-like shape as a whole. The first and second partition walls 225a and 225b are located at positions corresponding to steps 227a and 227b of the first wall 221. Accordingly, the first noise absorbing portion 226a, the second noise absorbing portion 226b, and the third noise absorbing portion 226c respectively include sub-spaces 223a, 223b, and 223c, the volumes of which differ from each other.

The part of first wall 221 forming the first noise absorbing portion 226a is defined as a first noise absorbing wall 221a. The part of the second wall 222 forming the first noise absorbing portion 226a and facing towards the first noise absorbing wall 221a is defined as a first noise insulating wall 222a. The part of the first wall 221 forming the second noise absorbing portion 226b is defined as a second noise absorbing wall 221b. The part of the second wall 222 forming the second noise absorbing portion 226b and facing towards the second noise absorbing wall 221b is defined as a second noise insulating wall 222b. Further, the part of the first wall 221 forming the third noise absorbing portion 226c is defined as a third noise absorbing wall 221c. The part of the second wall 222 forming the third noise absorbing portion 226c and facing towards the third noise absorbing wall 22.1c is defined as a third noise insulating wall 222c.

The first to third noise absorbing walls 221a to 221c each have an elongated rectangular shape and equal lateral and longitudinal dimensions. The first to third noise absorbing walls 221a to 221c are each provided with eight holes 228. The holes 228 are circular and have the same diameter. The holes 228 are formed at substantially equal intervals in the lateral and longitudinal directions of the first to third noise absorbing walls 221a to 221c. The holes 228 formed in the first noise absorbing wall 221a constitute a first noise absorbing hole group 220a. The holes 228 formed in the second noise absorbing wall 221b constitute a second noise absorbing hole group 220b. The holes 228 formed in the third noise absorbing wall 221c constitute a third noise absorbing hole group 220c. All the holes 228 constituting the first to third noise absorbing hole groups 220a to 220c have the same diameter, and hence, the same opening area. Also, the first to third noise absorbing hole groups 220a to 220c include the same number of holes 228. Accordingly, the respective opening areas of the first noise absorbing hole group 220a, the second noise absorbing hole group 220b, and the third noise absorbing hole group 220c, or the total sum of the opening areas of the holes 228 in the respective groups, are equal to one another.

The first to third noise absorbing walls 221a to 221c extend parallel to the opposing first to third noise insulating walls 222a to 222c. Since the first wall 221 has a step-like shape as a whole, the distance d1 between the first noise absorbing wall 221a and the first noise insulating wall 222a, the distance d2 between the second noise absorbing wall 221b and the second noise insulating wall 222b, and the distance d3 between the third noise absorbing wall 221c and the third noise insulating wall 222c are different from one another. Since the distances d1 to d3 are different from one another, the volume V1 of the first noise absorbing portion 226a, the volume V2 of the second noise absorbing portion 226b, and the volume V3 of the third noise absorbing portion 226c are different from one another. The volumes V1 to V3 of the first to third noise absorbing portions 226a to 226c are determined in accordance with the frequency range of the noise that is to be absorbed, that is, in accordance with the frequency range of the noise generated by the noise source. In the third embodiment, the volume V1 of the first noise absorbing portion 226a is larger than the volume V2 of the second noise absorbing portion 226b, and the volume V2 is larger than the volume V3 of the third noise absorbing portion 226c. The distances d1 to d3 each represent a minimum distance between the noise absorbing wall and the noise insulating wall in each of the noise absorbing portions.

As described above, the noise absorbing/insulating box 212 exhibits its noise absorbing capability as the result of air in the holes 228 acting as a mass and air in the space 223 acting as a spring. In the similar manner, the noise absorbing portions 226a to 226c also exhibit their noise absorbing capability as the result of air in the holes of the noise absorbing hole groups 220a to 220c acting as a mass, and air in the sub-spaces 223a to 223c of the noise absorbing portions 226a to 226c acting as a spring. Since the opening areas of the first to third noise absorbing hole groups 220a to 220c are the same, the masses of air in the first to third noise absorbing hole groups 220a to 220c are also the same. In contrast, since the volumes V1 to V3 of the first to third noise absorbing portions 226a to 226c are different from one another, the spring actions of air in the sub-spaces 223a to 223c are also different from one another. Since the spring actions are different among the first to third noise absorbing hole groups 220a to 220c, the frequency ranges of the noise absorbed in the first to third noise absorbing hole groups 220a to 220c are also different from one another. For this reason, the noise absorbing/insulating box 212 is capable of absorbing a wide range of noise due to the respective frequency ranges of noise that can be absorbed by the first to third noise absorbing portions 226a to 226c.

The noise absorbing/insulating box 212 of the third embodiment has the advantages described below.

The noise absorbing/insulating box 212 is designed such that the first to third noise absorbing portions 226a to 226c have different volumes V1 to V3. Thus, the noise absorbing effect is achieved based on the Helmholtz resonance principle when various types of noise in a wide frequency range pass through the holes of the noise absorbing hole groups 220a to 220c, and noise is absorbed by the noise absorbing/insulating box 212 more rapidly. Therefore, the frequency range of noise absorbed by the noise absorbing/insulating box 212 is wider compared to the conventional techniques. That is, the noise absorbing/insulating box 212 exhibits a preferable noise absorbing capability to noise in a wide frequency range. Accordingly, the noise absorbing/insulating box 212 of the third embodiment reduces noise in the passenger compartment that is generated by the drive train components, such as the noise of the engine or gears, more effectively than in the prior art. This achieves a greater level of quietness in the passenger compartment.

The first wall 221 including the first to third noise absorbing walls 221a to 221c has a step-like shape. The volumes V1 to V3 of the noise absorbing portions 226a to 226c can be varied easily by adjusting the number or positions of the steps 227a and 227b in the first wall 221. This fact facilitates a designer to design the noise absorbing/insulating box 212 and convenience in fabricating the noise absorbing/insulating box 212 is improved.

The noise absorbing/insulating box 212 includes the first to third noise insulating walls 222a to 222c respectively facing towards the first to third noise absorbing walls 221a to 221c. The first to third noise insulating walls 222a to 222c have no noise absorbing hole and separate the space 223 in the noise absorbing/insulating box 212 from the outside. Therefore, the first to third noise insulating walls 222a to 222c block the noise propagated through air and inhibit the noise generated by a noise source from leaking outside. Accordingly, the noise absorbing/insulating box 212 exhibits excellent capability of absorbing/insulating noise in a wide frequency range. Thus, noise is reduced and quietness is improved in the passenger compartment.

Two noise absorbing/insulating boxes 212 are arranged in the console 111 so as to block the path of noise generated by the drive train components and propagated in the console 111. The noise absorbing/insulating boxes 212 are located at optimal positions for absorbing noise generated by the noise source and for insulating the noise generated by the noise source. Therefore, the noise generated by the drive train components is effectively absorbed and insulated by installing the two noise absorbing/insulating boxes 212 in the console 111.

Fourth Embodiment

A fourth embodiment of the present invention will now be described with reference to FIGS. 12 and 13. FIG. 12 is a perspective view of a noise absorbing/insulating box 232, and FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12.

As shown in FIGS. 12 and 13, the noise absorbing/insulating box 232 has a planar first wall 241 and a second wall 242 facing towards the first wall 241. In the middle of the noise absorbing/insulating box 232, the second wall 242 is bent towards the first wall 241 so that part of the second wall 242 inclines toward the first wall 241. Side walls 244 of the noise absorbing/insulating box 232 are shaped in correspondence with the first wall 241 and second wall 242.

Three partition walls 245a, 245b, and 245c extend between the first wall 241 and the part of the second wall 242, inclining with respect to the first wall 241 such that the space 243 in the noise absorbing/insulating box 232 is divided into four sub-spaces 243a, 243b, 243c, and 243d. Thus, the noise absorbing/insulating box 232 has first to fourth noise absorbing portions 246a to 246d, which are hollow and separated from each other by the three partition walls 245a, 245b, and 245c. The first wall 241 is divided into first to fourth noise absorbing walls 241a to 241d respectively corresponding to the first to fourth noise absorbing portions 246a to 246d. The second wall 242 is also divided into first to fourth noise insulating walls 242a to 242d in the same manner.

Each of the first to fourth noise absorbing walls 241a to 241d is provided with circular holes 248 having the same diameter and arranged at substantially equal intervals in the lateral and longitudinal directions of the noise absorbing/insulating box 232. The holes 248 formed in the first to fourth noise absorbing walls 241a to 241d respectively constitute first, second, third, and fourth noise absorbing hole groups 240a, 240b, 240c and 240d. The opening areas of the second to fourth noise absorbing hole groups 240b to 240d, which are the total sums of the opening areas of the holes 248 in the respective groups, are equal to one another. The opening area of the first noise absorbing hole group 240a is larger than the opening areas of the second to fourth noise absorbing hole groups 240b to 240d.

Since the second wall 242 is partially inclined, the respective distances d1 to d4 between the first to fourth noise absorbing walls 241a to 241d and the first to fourth noise insulating walls 242a to 242d become smaller in this order towards the distal side of the noise absorbing/insulating box 232 (downward side in FIGS. 12 and 13). The volumes V1, V2, V3, and V4 of the first to fourth noise absorbing portions 246a to 246d are determined in accordance with the distances d1 to d4. Since the volumes V1 to V4 differ from one another and the opening area of the first noise absorbing wall 241a differ from the opening areas of the second to fourth noise absorbing walls 241b to 241d, frequency ranges of noise absorbed by the first to fourth noise absorbing portions 246a to 246d differ from one another. The volumes V2 to V4 of the second to fourth noise absorbing portions 246b to 246d are determined in accordance with the frequency ranges of the noise that is to be absorbed. In the fourth embodiment, the volumes become smaller in the order of the second noise absorbing portion 246b, the third noise absorbing portion 246c, and then the fourth noise absorbing portion 246d. The volume V1 of the first noise absorbing portion 246a is obviously larger than the volumes V2 to V4 of the second to fourth noise absorbing portions 246b to 246d, and the opening area of the first noise absorbing hole group 240 is also obviously larger than the other opening areas.

Accordingly, the noise absorbing/insulating box 232 of the fourth embodiment has the advantages described below.

The bent portion 247 of the second wall 242 is inclined relative to the first wall 241. Therefore, the respective volumes V2 to V4 of the noise absorbing portions 246b to 246d may easily be varied by adjusting the angle α between the bent portion 247 of the second wall 242 and the first wall 241. This facilitates the designing and manufacturing of the noise absorbing/insulating box 232.

Fifth Embodiment

A noise absorbing/insulating box 252 according to a fifth embodiment of the present invention will now be described with reference to FIGS. 14 and 15.

As shown in FIGS. 14 and 15, the noise absorbing/insulating box 252 includes noise absorbing/insulating sub-boxes 252a to 252c of different sizes. The noise absorbing/insulating box 252 is formed by adhesively bonding the sides of the noise absorbing/insulating sub-boxes 252a to 252c to one another.

The noise absorbing/insulating box 252 of the fifth embodiment has the advantageous described below.

The noise absorbing/insulating box 252 is formed by adhesively bonding the noise absorbing/insulating sub-boxes 252a to 252c, which have simple shapes. Accordingly, the noise absorbing/insulating box 252 is easy to manufacture. The noise absorbing/insulating sub-boxes 252a to 252c respectively absorb noise in different frequency ranges. Therefore, the noise absorbing/insulating box 252 exhibits a preferable noise absorbing capability relative to noise in a wide frequency range by optimizing the combination of the noise absorbing/insulating sub-boxes 252a to 252c.

Sixth Embodiment

A sixth embodiment of the present invention will now be described with reference to FIGS. 16 and 17. In the sixth embodiment, five noise absorbing/insulating boxes 112 of the first embodiment (112A to 112C) are installed inside a console 111.

As shown in FIG. 16, a console 111 is arranged between the driver's seat and the passenger seat of a vehicle. A gearshift lever 312 is arranged in the front portion of the console 111. Cup holders 307 are arranged just behind the gearshift lever 312 on the driver's seat side of the console 111. A parking brake 308 is located next to the cup holder 307 on the passenger seat side of the console 111. A storage box 310 is provided behind the cup holder 307 to accommodate small articles. An ash tray 309 is provided behind the storage box 310. The noise absorbing/insulating boxes 112A to 112C are provided in the console 111 as shown by the broken lines in FIG. 16.

As shown in FIGS. 16 and 17, the five noise absorbing/insulating boxes 112A to 112C are arranged at positions corresponding to the gearshift lever 312, the cup holders 307, and the parking brake 308. That is, the noise absorbing/insulating boxes 112A to 112C are located in the front part of the console 111 so as to surround the mechanical parts associated with the gearshift lever 312 and parking brake 308. The arrow FR in FIG. 17 indicates the front direction.

In the sixth embodiment, three different types of noise absorbing/insulating boxes 112A to 112C having different widths are employed. The first noise absorbing/insulating box 112A has the smallest width, and the third noise absorbing/insulating box 112C has the largest width. Accordingly, the second noise absorbing/insulating box 112B has an intermediate width between those of the first noise absorbing/insulating box 112A and third noise absorbing/insulating box 112C.

Two first noise absorbing/insulating boxes 112A are arranged on the left and right sides of the gearshift lever 312 such that the holes 128 of the two first noise absorbing/insulating boxes 112A face each other. A third noise absorbing/insulating box 112C is provided just behind the gearshift lever 312 with the holes 128 of the third noise absorbing/insulating box 112C facing the front side of the vehicle. That is, the gearshift lever 312 is surrounded from three directions by the three noise absorbing/insulating boxes consisting of the first two first noise absorbing/insulating boxes 112A and the third noise absorbing/insulating box 112C.

A second noise absorbing/insulating box 112B is provided on the driver's seat side of the cup holder 307. The holes 128 of the second noise absorbing/insulating box 112B face toward the cup holder 307, that is, toward the inside of the console 111. Another third noise absorbing/insulating box 112C is provided behind the cup holder 307 and the parking brake 308 with the holes 128 of the third noise absorbing/insulating box 112C facing the front side of the vehicle.

As described above, the holes 128 of all five noise absorbing/insulating boxes 112A to 112C face the front side of the vehicle or the inside of the console 111. That is, the holes 128 of the noise absorbing/insulating boxes 112A to 112C are directed to the noise source constituted by drive train components such as the engine and the transmission.

The noise absorbing/insulating boxes 112A to 112C are respectively held and fixed by a plurality of guide walls 316 and 317 formed on the inner surface of the side walls of the console 111. More specifically, a pair of guide walls 317 are formed spaced apart from each other by a distance equal to the thickness of the third noise absorbing/insulating box 112C to hold the third noise absorbing/insulating box 112C. Two pairs of the guide walls 317 facing towards each other hold the third noise absorbing/insulating box 112C therebetween.

A pair of guide walls 316 each having a hook 316a are spaced from each other by a distance equal to the width of the first noise absorbing/insulating box 112A or second noise absorbing/insulating box 112B to hold the first noise absorbing/insulating box 112A or second noise absorbing/insulating box 112B. The distal end of the hook 316a of the front guide wall 316 and the distal end of the hook 316a of the rear guide wall 316 face each other. The distance from the hook 316a of the guide wall 316 to the side wall of the console 111 where the guide wall 316 is formed is equal to the thickness of the first or second noise absorbing/insulating box 112A or 112B. The hooks 316a and the side walls of the console 111 hold the first noise absorbing/insulating box 112A and the second noise absorbing/insulating box 112B.

If the total area of the holes 128 is in the range of 0.5 to 15.0% of the area of the first wall 121 having the holes 128, the noise absorbing/insulating box 112 absorbs noise generated by the drive train effectively. In the sixth embodiment, the total area of the holes 128 is about 1.5% of the area of the first wall 121 having the holes 128. When the percentage is 1.5%, the noise absorbing/insulating box 112 effectively absorbs noise having a frequency of about 800 Hz. Noise having a frequency of about 800 Hz is generated by the transmission when the vehicle is traveling and perceived as an unpleasant noise by the driver.

If the diameter of the holes 128 is 10 mm or less, the noise absorbing/insulating box 112 absorbs noise effectively. Additionally, when the diameter of the holes 128 is 0.01 mm or greater, more preferably, 0.1 mm or greater, the noise absorbing/insulating box 112 is capable of effectively absorbing noise.

In the sixth embodiment, the holes 128 are directed toward the drive train of the vehicle. Therefore, noise generated by the drive train when the vehicle is traveling is guided into the noise absorbing/insulating boxes 112A to 112C through the holes 128 and effectively attenuated. This absorbs the noise in the passenger compartment. As a result, noise leaking into the passenger compartment through the gaps of the console 111 is reduced.

The sixth embodiment has the advantages described below.

The holes 128 are directed to the drive train. Therefore, noise from the drive train is reduced effectively. Furthermore, the possibility of sound from an audio system being absorbed is reduced.

The total area of the holes 128 is 1.5% of the area of the first wall 121. Therefore, the noise absorbing/insulating boxes 112A to 112C effectively reduce noise generated by the transmission.

The noise absorbing/insulating boxes 112A to 112C are attached to the console 111 by inserting the noise absorbing/insulating boxes 112A to 112C between the guide walls 316 and 317. Accordingly, it is easy to install the noise absorbing/insulating boxes 112A to 112C. Moreover, no special parts are required to attach the noise absorbing/insulating boxes 112A to 112C to the console 111, and an increase of the number of parts is avoided.

The holes 128 of the five noise absorbing/insulating boxes 112A to 112C installed in the console 111 are directed in a number of different directions. Accordingly, noise is effectively absorbed from various directions.

Seventh Embodiment

A seventh embodiment of the present invention will now be described with reference to FIGS. 18 and 19.

A typical vehicle includes a glove compartment for accommodating small articles. A glove compartment 320 according to the seventh embodiment includes a lid 321 and a container 322 formed integrally with the lid 321. The lid 321 and the container 322, which are integrally formed with each other, are pulled open. An inner cover 323 is attached to an instrument panel 325 so as to surround the container 322. One first noise absorbing/insulating box 112D and two second noise absorbing/insulating boxes 112E are attached to the inner cover 323 next to the gaps between the lid 321 and the instrument panel 325. The noise absorbing/insulating boxes 112D and 112E are arranged along the rear wall and the left and right side walls of the inner cover 323, respectively. The noise absorbing/insulating boxes 112D and 112E are held by hooks 316a of the guide walls 316 formed integrally with the inner cover 323 such that the holes 128 face the outer side of the glove compartment 320.

The holes 128 of the first and second noise absorbing/insulating boxes 112D and 112E respectively provided on the rear wall and right wall of the inner cover 323 face the engine room and therefore effectively absorbs engine noise and transmission noise. The holes 128 of the second noise absorbing/insulating box 112E provided on the left wall of the inner cover 323 face the outer side of the vehicle and therefore effectively absorb noise picked up from the road.

In addition to the advantages of the sixth embodiment, the noise absorbing/insulating boxes 112D and 112E of the seventh embodiment has the advantages described below.

The noise absorbing/insulating box 112D and 112E are arranged next to the gaps between the lid 321 and the instrument panel 325. Thus, noise entering the passenger compartment through the gaps is effectively reduced.

Eighth Embodiment

An eighth embodiment of the present invention will now be described with reference to FIG. 20.

A glove compartment 330 according to the eighth embodiment includes a lid 321 and a container 322, which is separate from the lid 321.

One first noise absorbing/insulating box 112F and two second noise absorbing/insulating boxes 112G are provided next to the gaps between the container 322 and the instrument panel 325. The noise absorbing/insulating boxes 112F and 112G are arranged along the rear wall and the left and right walls of the container 322, respectively. The noise absorbing/insulating boxes 112F and 112G are held by hooks 316a of guide walls 316 formed integrally with the container 322 such that the holes 128 face the outer side of the glove compartment 330.

The noise absorbing/insulating boxes 112F and 112G of the eighth embodiment has the same advantages as the noise absorbing/insulating boxes 112D and 112E of the seventh embodiment.

It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the present invention may be embodied in the following forms.

In the first and second embodiments, the noise absorbing/insulating boxes 112 and 132 may each include three or more noise absorbing portions. For example, in the first embodiment, the noise absorbing/insulating box 112 may have three or more different types of noise absorbing holes with different opening areas, that is, three or more different types of noise absorbing portions. In the second embodiment, the noise absorbing/insulating box 132 may have three or more noise absorbing/insulating sub-boxes.

In the first embodiment, the noise absorbing/insulating structure includes the two noise absorbing/insulating boxes 112. However, the noise absorbing/insulating structure may include one noise absorbing/insulating box 112 or three or more noise absorbing/insulating boxes 112.

In each of the above embodiments, the noise absorbing/insulating box 112, 132, 212, 232 may be arranged at any position in accordance with the position of a noise source or the shape of a component on which the noise absorbing/insulating box is to be attached. For example, the noise absorbing/insulating box 112 may be adhesively bonded to the inner surface of each of the side walls 111a of the console 111.

In the first embodiment, the holes 128 constituting the first and second noise absorbing hole groups 120a and 120b may be formed at any position (randomly) on the first and second noise absorbing walls 121a and 121b, respectively. Also, each of the first and second noise absorbing hole groups 120a and 120b may be constituted by holes having different opening areas.

In the first embodiment, the holes 128 constituting the first and second noise absorbing hole groups 120a and 120b does not have to be spaced at equal intervals in the longitudinal and lateral directions of the noise absorbing/insulating box 112.

In the first and second embodiments described above, the volume of the first noise absorbing portion 126a is equal to the volume of the second noise absorbing portion 126b. However, the volume of the first noise absorbing portion 126a may differ from the volume of the second noise absorbing portion 126b.

In the second embodiment, the noise absorbing/insulating box 132 may be constituted by assembling a plurality of noise absorbing/insulating boxes 112 of the first embodiment into a single body. Alternatively, the noise absorbing/insulating sub-boxes may be attached to the console 111 without being formed integrally with each other as separate bodies.

In each of the above embodiments, the holes 128, 148, 149, 228, and 248 are all circular. However, the holes 128, 148, 149, 228 and 248 may have any shape. For example, the hole 128 may have an elliptical or polygonal shape. The polygonal shape may be, for example, the shape of a triangle or a diamond.

In the first and second embodiments, the noise absorbing/insulating box 112, 132 is thin and has a rectangular box shape. However, the shape of the noise absorbing/insulating box 112, 132 may be modified according to the required noise absorbing capability or the position where the noise absorbing/insulating box 112, 132 is installed. For example, the shape of the noise absorbing/insulating box 112, 132 may be spherical, disk-like, or trapezoidal.

In each of the above embodiments, the noise absorbing/insulating box 112, 132, 212, 232 may be attached to a vehicle interior equipment item other than the console 111, for example, to an instrument panel, a door trim, a rear trim, a roof trim, or a pillar trim. In this case, the noise absorbing/insulating box 112, 132, 212, and 232 may be used to absorb noise other than noise from the vehicle's drive train components, for example, sound from an audio system or a human voice.

In the first and second embodiments, as long as the noise absorbing hole groups of the respective noise absorbing portions have different opening areas, the noise absorbing hole group may be composed of a single hole.

In the third embodiment, the space 223 in the noise absorbing/insulating box 212 may be divided into two, or four or more sub-spaces. In this case, the number of the steps 227a and 227b of the first wall 221, and the number of the partition walls 225a and 225b extending from the steps 227a and 227b to second wall 222 may be changed from one to three or more so that the space 223 in the noise absorbing/insulating box 212 is divided into two or into four or more sub-spaces.

In the third embodiment, the second wall 222 may have a step-like shape and the first wall 221 may have a planar shape. Further, the first wall 221 and the second wall 222 may both have a step-like shape.

In the third embodiment, the distances d1 to d3 between the respective noise absorbing walls and the respective noise insulating walls in the first to third noise absorbing portions 226a to 226c become smaller in this order. However, the relationship of the distances d1, d2, and d3 may be changed as required. In this case, the cross-sectional shape of the noise absorbing/insulating box 212 may be concave or convex.

In the third and fourth embodiments, the noise absorbing hole groups 220a to 220c have an identical opening area, and the noise absorbing hole groups 240b to 240d also have an identical opening area. However, the noise absorbing hole groups 220a to 220c, and 240b to 240d may have different opening areas, respectively.

In the fourth embodiment, part of the second wall 242 is inclined with respect to the first wall 241. Instead, the entire second wall 242 may be inclined with respect to the first wall 241.

In the fourth embodiment, the space 243 in the noise absorbing/insulating box 232 may be divided into three or less sub-spaces or five or more sub-spaces. In this case, the number of the partition walls 245a to 245c extending from the second wall 242 to the first wall 241 is changed to two or less or four or more so that the space 243 in the noise absorbing/insulating box 232 is divided into three or less sub-spaces or five or more sub-spaces.

In the fourth embodiment, the middle of the second wall 242 may be bent more gradually (or with a larger curvature radius) than that shown in FIG. 12.

In the fourth embodiment, the bent portion of the second wall 242 may be formed in the first wall 241.

In the third to fifth embodiments, the side walls 224, 244 provided along the circumference of the first and second walls may be step-like or slope-shaped. For example, a pair of the opposing side walls 224, 244 may be inclined so that the noise absorbing/insulating box 212, 232 has a trapezoidal or triangular shape as seen from the front. Alternatively, the side wall 224, 244 may have a step-like shape so that the noise absorbing/insulating box has a concave or convex shape as seen from the front.

The noise absorbing/insulating box 232 of the fourth embodiment may be composed of a plurality of noise absorbing/insulating sub-boxes like the noise absorbing/insulating box 252 of the fifth embodiment.

In the seventh and eighth embodiments, the noise absorbing/insulating box 112 may be attached to the upper side or lower side of the glove compartment 320, 330.

In the seventh embodiment, a plurality of noise absorbing/insulating boxes 112 is attached to the inner cover 323. Instead, a plurality of noise absorbing/insulating boxes 112 may be attached directly to the container 322 so as to surround the container 322. In the third embodiment, the noise absorbing/insulating box 112 is arranged outside the container 322. Instead, the noise absorbing/insulating box 112 may be arranged inside the container 322. In these cases, the noise absorbing/insulating box 112 provided for the container 322 may be covered with a sheet or a cover such that the noise absorbing/insulating box 112 cannot be seen by passengers.

In each of the above embodiments, the noise absorbing/insulating box 112, 132, 212, 232 is attached to vehicle interior equipment such as the console 111 by the guide walls 115, 316, and 317. However, as shown in FIG. 21A or 21B, for example, the noise absorbing/insulating box 112, 132, 212, 232 may be provided with a tongue 327 having a hole 326 so that the noise absorbing/insulating box 112, 132, 212, 232 is fixed to part of the vehicle body by means of the tongue 327 and a screw (not shown). Further, the noise absorbing/insulating box 112, 132, 212, and 232 may be bonded to part of the vehicle body by the use of an adhesive.

In the sixth embodiment, if there is sufficient space between the cup holder 307 and the parking brake 308, the second noise absorbing/insulating box 112B may be arranged between the cup holder 307 and the parking brake 308. Further, if the vehicle is provided with a pedal parking brake, the second noise absorbing/insulating box 112B may be arranged at the position of the parking brake 308 in the sixth embodiment. In this case, the holes 128 of the second noise absorbing/insulating box 112B still face the inside of the console 11.

In the sixth to eighth embodiments, the noise absorbing/insulating box 112 of the first embodiment is attached to the console 111 or to the glove compartment 320, 330. Instead, the noise absorbing/insulating box 132, 212, 232, or 252 of any of the second to fifth embodiments may be attached to the console 111 or to the glove compartment 320, 330 in a similar manner to the sixth to eighth embodiments.

The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.

Claims

1. A noise absorbing structure for absorbing noise, the structure comprising:

a first noise absorbing portion that is hollow and includes one or more first holes; and

a second noise absorbing portion that is hollow and includes one or more second holes,

wherein the one or more first holes has a total area different from that of the one or more second holes.

2. The noise absorbing structure according to claim 1, wherein the one or more first holes include two or more first holes each with the same opening area, and the one or more second holes include two or more second holes each with the same opening area.

3. The noise absorbing structure according to claim 1, wherein each of the first and second noise absorbing portions includes a noise insulating wall for insulating noise.

4. The noise absorbing structure according to claim 1, wherein the first noise absorbing portion and the second noise absorbing portion each include a volume that is the same as one another.

5. The noise absorbing structure according to claim 1, wherein the noise absorbing structure is arranged in a vehicle including interior equipment and a drive train for driving the vehicle, the noise absorbing structure being installed in the interior equipment such that the one or more first and second holes are directed toward the drive train.

6. The noise absorbing structure according to claim 5, wherein the first noise absorbing portion has a first noise absorbing wall including the one or more first holes, the second noise absorbing portion has a second noise absorbing wall including one or more second holes, and the total area of the one or more first hole and the one or more second holes is 0.5 to 15.0% of the area of the first and second noise absorbing walls.

7. The noise absorbing structure according to claim 5, wherein the one or more first holes and the one or more second holes each have a diameter that is ten millimeters or less.

8. The noise absorbing structure according to claim 5, wherein the vehicle interior equipment includes a guide wall for holding the noise absorbing structure, and the noise absorbing structure is held by the guide wall.

9. The noise absorbing structure according to claim 5, wherein the interior equipment includes a plurality of parts assembled with a space defined therebetween, and the noise absorbing structure is arranged as a part next to the space.

10. The noise absorbing structure according to claim 5, wherein the first and second noise absorbing portions constitute a noise absorbing body, and the noise absorbing body is one of a plurality of noise absorbing bodies arranged such that the first and second holes in the noise absorbing bodies are directed in different directions.

11. A noise absorbing/insulating body for absorbing and insulating noise, the body comprising:

a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall; and

a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall,

wherein the one or more first holes has a total area different from that of the one or more second holes.

12. A noise absorbing structure for absorbing noise, the structure comprising:

a first sub-box that is hollow and includes one or more first holes; and

a second sub-box that is hollow, includes one or more second holes, and has the same shape as the first sub-box,

wherein the one or more first holes has a total area different from that of the one or more second holes.

13. A noise absorbing structure for absorbing noise, the structure comprising:

a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes; and

a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes,

wherein the first noise absorbing portion and the second noise absorbing portion each have a volume that is different from one another.

14. The noise absorbing structure according to claim 13, wherein:

the first noise absorbing portion includes a first opposing wall facing towards the first noise absorbing wall;

the second noise absorbing portion includes a second opposing wall facing towards the second noise absorbing wall; and

at least either a set of the first and second noise absorbing walls or a set of the first and second opposing walls includes a step such that the noise absorbing structure corresponds as a whole to a step-like shape.

15. The noise absorbing structure according to claims 13, wherein:

the first noise absorbing portion includes a first opposing wall facing towards the first noise absorbing wall; and

the second noise absorbing portion includes a second opposing wall facing towards the second noise absorbing wall,

either one of a set of the first and second noise absorbing walls or a set of the first and second opposing walls includes a part inclined with respect to the other one of the set of the first and second noise absorbing walls or the set of the first and second opposing walls.

16. The noise absorbing structure according to claim 13, wherein the noise absorbing structure is arranged in a vehicle including interior equipment and a drive train for driving the vehicle, the noise absorbing structure being installed in the interior equipment such that the one or more first and second holes are directed toward the drive train.

17. The noise absorbing structure according to claim 16, wherein the total area of the one or more first holes and the one or more second holes is 0.5 to 15.0% of the area of the first and second noise absorbing walls.

18. The noise absorbing structure according to claim 16, wherein the one or more first holes and the one or more second holes each have a diameter that is ten millimeters or less.

19. The noise absorbing structure according to claim 16, wherein the vehicle interior equipment includes a guide wall for holding the noise absorbing structure, and the noise absorbing structure is held by the guide wall.

20. The noise absorbing structure according to claim 16, wherein the interior equipment includes a plurality of parts assembled with a space defined therebetween, and the noise absorbing structure is arranged as a part next to the space.

21. The noise absorbing structure according to claim 16, wherein the first and second noise absorbing portions constitute a noise absorbing body, and the noise absorbing body is one of a plurality of noise absorbing bodies arranged such that the first and second holes in the noise absorbing bodies are directed in different directions.

22. A noise absorbing/insulating structure for absorbing and insulating noise, the structure comprising:

a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall; and

a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall,

wherein the first noise absorbing portion and the second noise absorbing portion each include a volume that is different from one another.

23. A noise absorbing structure for absorbing noise, the structure comprising:

a first sub-box that is hollow and includes one or more first holes; and

a second sub-box that is hollow and includes one or more second holes having the same shape as the first holes,

wherein the one or more first holes has a total area and the one or more second holes has a total area that is the same as the total area of the one or more first holes, and the first sub-box and the second sub-box each have a volume that is different from one another.