Sound control member and method for manufacturing sound control member

Abstract

To provide an acoustic control member capable of further improving sound quality in sound emission from a speaker, and to provide a method of manufacturing the acoustic control member.SOLUTION: The sound control mat (S) includes a vibration damping layer (2) that suppresses vibration generated in an outer panel due to sound emitted from a speaker, and a sound absorbing layer (1) that is laminated on a surface of the vibration damping layer (2) on a speaker side and includes a sound absorbing material, wherein a recessed area (1B) having a recessed shape when viewed from the speaker side and a protruding area (1A) having a protruding shape when viewed from the speaker side are formed on the surface of the sound absorbing layer (1) on the speaker side. The densities of the sound absorbing material in the recessed areas 1B are different from the densities of the sound absorbing material in the projecting areas 1A.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present application relates to the technical field of an acoustic control member and a method for manufacturing the same, more particularly to an acoustic control member disposed on the rear side of a speaker and spaced apart from the rear side, and a method for manufacturing the same. Background technology

[0002] There has been a demand for improved sound quality for speakers installed in vehicles. One example of prior art related to this demand is the technology described in Patent Document 1 below. The technology described in Patent Document 1 involves forming a polyurethane film on the surface of a urethane material as a manufacturing method for a vibration-damping member that suppresses vibrations caused by sound emitted from the speaker. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-232735 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in light of recent improvements in the performance of speakers themselves, when placing them in small spaces such as vehicles, there is a demand for further improvements in the audible sound quality by preventing degradation of sound quality due to the shape and size of the space.

[0005] Therefore, the present application has been made in consideration of the above-mentioned demands, and one example of its objective is to provide an acoustic control member that can prevent a deterioration in the sound quality of speakers inside a vehicle, and a method for manufacturing such an acoustic control member. [Means for solving the problem]

[0006] In order to solve the above problem, the invention described in claim 1 provides an acoustic control member arranged on the rear side of a speaker and spaced apart from the rear side, the acoustic control member comprising: a vibration-damping layer that suppresses vibrations that occur in a support member to which the acoustic control member is attached due to sound emission from the speaker; and a sound-absorbing layer that is laminated on the speaker-side surface of the vibration-damping layer and contains a sound-absorbing material, the speaker-side surface of the sound-absorbing layer being formed with a concave region that is concave when viewed from the speaker side and a convex region that is convex when viewed from the speaker side, the density of the sound-absorbing material in the concave region and the density of the sound-absorbing material in the convex region being different, and the density of the sound-absorbing material in a surface layer of a sloped portion located between the concave region and the convex region being higher than the density of the sound-absorbing material inside the sloped portion.

[0007] In order to solve the above-mentioned problems, the invention described in claim 7 provides a method for manufacturing an acoustic control member that manufactures an acoustic control member that is to be placed on the rear side of a speaker and at a distance from the rear side, the method comprising: a sound absorbing layer forming step of hot-pressing a base material that contains a sound absorbing material to form a sound absorbing layer that has concave and convex regions on its surface; a vibration-damping layer forming step of forming a vibration-damping layer that contains an elastic material on the surface of the sound absorbing layer opposite to the surface on which the convex and concave regions are formed, the vibration-damping layer comprising an elastic material that suppresses vibrations that occur in a mounting member to which the acoustic control member is attached due to sound emission from the speaker; and a surface layer forming step of forming a surface layer on the surface of the sound absorbing layer on which the convex and concave regions are formed, wherein the density of the sound absorbing material in the concave regions is different from the density of the sound absorbing material in the convex regions, and the density of the sound absorbing material in a surface layer portion of a sloped portion located between the concave and convex regions is higher than the density of the sound absorbing material inside the sloped portion, and the acoustic control member is configured so that the side on which the surface layer is formed faces the speaker. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an enlarged partial front view showing the configuration of the acoustic control member according to the embodiment. [Figure 2]FIG. 2 is a side view conceptual diagram showing the use state of the sound control mat of the embodiment. [Figure 3] 1A and 1B are plan views showing the structure of a sound control mat according to an embodiment of the present invention, where FIG. 1A is the plan view and FIG. 1B is a front view showing the structure. [Figure 4] 3(a) is a cross-sectional view of the A-A' portion of FIG. 3(a), showing the structure of the sound control mat of the embodiment. [Figure 5] 3(a) is an enlarged partial front view showing the structure of the sound control mat of the embodiment, (b) is an external perspective view showing the structure of the sound control mat, and (c) is an enlarged partial front view showing an example of the effect of the structure of the sound control mat. [Figure 6] 1A and 1B are diagrams showing the manufacturing process of the sound control mat of the embodiment, in which (a) is a flowchart showing the manufacturing process, and (b) is a side view conceptual diagram showing the configuration of the manufacturing device for the sound control mat. [Figure 7] 10A and 10B are plan views and the like showing the structure of a sound control mat of a first modified example, where (a) is the plan view and (b) is a front view showing the structure. [Figure 8] 10A and 10B are plan views and the like showing the structure of a sound control mat of a second modified example, where (a) is the plan view and (b) is a front view showing the structure. [Figure 9] 10A and 10B are plan views and the like showing the structure of a sound control mat of a third modified example, where (a) is the plan view and (b) is a front view showing the structure. [Figure 10] 10A and 10B are plan views and the like showing the structure of a sound control mat of a fourth modified example, where (a) is the plan view and (b) is a front view showing the structure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is an enlarged partial front view showing the configuration of an acoustic control member according to the embodiment.

[0010] As shown in Fig. 1, the acoustic control member S according to the embodiment is an acoustic control member disposed on the rear side of the speaker with a gap therebetween, and includes a vibration-damping layer 2 and a sound-absorbing layer 1. In Fig. 1, the direction of the speaker as viewed from the acoustic control member S according to the embodiment is indicated by a white arrow.

[0011] In the acoustic control member S of the above embodiment, the vibration-damping layer 2 suppresses vibrations that occur in the support member to which the acoustic control member S is attached, due to sound emitted from the speaker.

[0012] On the other hand, the sound absorbing layer 1 is laminated on the speaker side surface of the vibration damping layer 2 and contains a sound absorbing material.

[0013] The speaker-side surface of the sound-absorbing layer 1 is formed with a concave region 1B that is concave when viewed from the speaker side, and a convex region 1A that is convex when viewed from the speaker side. The concave region density, which is the density of the sound-absorbing material in the concave region 1B, is different from the convex region density, which is the density of the sound-absorbing material in the convex region 1A, and the density of the sound-absorbing material in the surface layer of the sloped portion located between the concave region 1B and the convex region 1A is higher than the density of the sound-absorbing material inside the sloped portion.

[0014] As explained above, the configuration of the acoustic control member S of the embodiment comprises the vibration-damping layer 2 and the sound-absorbing layer 1, with concave regions 1B and convex regions 1A formed on the speaker-side surface of the sound-absorbing layer 1, and the density of the sound-absorbing material differs between the concave regions 1B and the convex regions 1A. The difference in sound absorption effect due to the difference in density makes it possible to improve the sound-absorbing effect of the acoustic control member S as a whole, and by removing factors that degrade sound quality in the environment in which the speaker is installed (i.e., preventing a decline in sound quality), the sound quality when listening to sound emitted from the speaker is improved. [Example]

[0015] Next, specific examples corresponding to the above-described embodiments will be described with reference to Figures 2 to 6. The examples described below are examples in which the present application is applied to an acoustic control mat that is attached to the inside of a vehicle door, for example, to suppress the effects of events that cause deterioration in the sound quality of a speaker attached inside the vehicle (for example, unwanted resonance of the door to which the speaker is attached).

[0016] 2 is a conceptual side view showing the state of use of the sound control mat of the embodiment, FIG. 3 is a plan view showing the structure of the sound control mat, and FIG. 4 is a cross-sectional view of the A-A' section of FIG. 3(a) showing the structure of the sound control mat. Furthermore, FIG. 5 is an enlarged partial front view showing the structure of the sound control mat, and FIG. 6 is a diagram showing the manufacturing process of the sound control mat. In FIGS. 2 to 5, the same component numbers as those of the sound control member S of the embodiment shown in FIG. 1 are used for the components of the embodiment corresponding to the components of the sound control member S of the embodiment.

[0017] First, before describing the specific structure of the sound control mat S of the embodiment, the state of use of the sound control mat S will be described with reference to Fig. 2. As shown in Fig. 2, the sound control mat S of the embodiment is disposed, for example, by being attached to the inside of an outer panel OP of a vehicle door D at a distance from the rear side of a speaker SP that is attached to an inner panel IP of the door D facing the interior of the vehicle. In the above-described positional relationship with the speaker S, the sound control member S of the embodiment has three functions, as shown in Fig. 2: (i) a function of absorbing sound waves emitted to the rear side by the speaker S, (ii) a function of reflecting / diffusing the sound waves, and (iii) a function of suppressing unnecessary vibrations generated in the outer panel OP by the sound waves.

[0018] In order to achieve each of the above functions, the acoustic control mat S of the embodiment comprises, as shown in Figures 3 to 5, a vibration-damping layer 2, a sound-absorbing layer 1 that is laminated on the speaker SP side of the vibration-damping layer 2 in the acoustic control mat S and contains a sound-absorbing material, and a surface layer 3 that is laminated on the speaker SP side of the sound-absorbing layer 1.

[0019] In this configuration, the vibration-damping layer 2 performs the function of (iii) above, as well as the function of fixing the sound control mat S to the inside of the outer panel OP. Specific examples of such a vibration-damping layer 2 include a rubber-based sheet material as an elastic material, a metal (specifically, aluminum, copper, lead, or the like) sheet material, a high-density resin material, or a butyl-based sheet material. Furthermore, the surface of the vibration-damping layer 2 opposite the sound-absorbing layer 1 is fixed to the inside of the outer panel OP using, for example, adhesive tape, thereby fixing the sound control mat S to the outer panel OP.

[0020] Next, the sound absorbing layer 1 performs the function (i) above. To this end, the surface of the sound absorbing layer 1 facing the speaker SP is formed with a plurality of so-called "wedge-shaped" concave regions 1B that are concave when viewed from the speaker side, and a plurality of convex regions 1A that are convex when viewed from the speaker side. The density of the sound absorbing material in each of the concave regions 1B and each of the convex regions 1A is made different from the density of the sound absorbing material in the convex regions 1A. Here, the "density" of the sound absorbing material is calculated, for example, by the following formula (1) using material pieces (e.g., cubic test pieces with sides of 5 millimeters) of the same volume for the sound absorbing material in the concave regions 1B and the sound absorbing material in the convex regions 1A:

[0021] Density (unit: kg / m 3 )=(m / V)×106 …(1) where "m" is the mass of the material piece (unit: g), and "V" is the volume of the material piece (unit: mm 3 )

[0022] More specifically, the density of the sound-absorbing material in the recessed regions 1B is different from the density of the sound-absorbing material in the protruding regions 1A. For example, in the enlarged front view shown in FIG. 5(a), the density of the sound-absorbing material in one recessed region 1B is higher than the density of the sound-absorbing material in the protruding regions 1A adjacent to that recessed region 1B. The thickness of the highest-density portion at the bottom (protruding end) of the recessed region 1B in FIG. 5(a) is, for example, approximately 0.5 millimeters. The density of the sound-absorbing material in the surface layer of the sloped portions formed between that recessed region 1B and each of the protruding regions 1A adjacent to that recessed region 1B is higher than the density of the sound-absorbing material inside the sloped portions. The above-described partial difference in the density of the sound-absorbing material in the sound-absorbing layer 1 occurs because the sound-absorbing layer 1 is formed / manufactured by a hot press process, as will be described later. Due to this difference in density, the frequency range of sound waves absorbed by the sound-absorbing layer 1 is wider than when the density is uniform. In other words, since the higher the density of a sound-absorbing material, the higher the frequency of the sound waves that can be absorbed, the sound-absorbing layer 1 of the embodiment with different densities can absorb a wider range of sound waves than a sound-absorbing layer with a uniform density, and as a result, it can be said that the function (i) above is further improved. Specific examples of the sound-absorbing material for the sound-absorbing layer 1 include foamed urethane materials (low-density / high-density urethane foam materials), EPDM (ethylene propylene diene rubber) materials, and foamed polyethylene materials. Even if the material is somewhat hard, any material with a high expansion ratio (i.e., low density) can be used as the sound-absorbing material for the sound-absorbing layer 1.

[0023] Next, the surface layer 3 performs the function (ii) above. To this end, the surface layer 3 is manufactured by applying, as a paint, the same material as the sound-absorbing material of the sound-absorbing layer 1 to the surface of the sound-absorbing layer 1 facing the speaker SP, as described below, and then drying the paint. Here, since the sound-absorbing layer 1 of the embodiment is molded / manufactured by a hot pressing process described below, the surface of the sound-absorbing layer 1 facing the surface layer 3 is in a dense state with few pores (i.e., a so-called skin layer) when the material for the surface layer 3 is applied. This prevents the applied material for the surface layer 3 from seeping into the sound-absorbing layer 1, and the surface layer 3 is formed effectively and efficiently. As a result, the sound wave reflection / diffusion function (ii) above is efficiently realized, as illustrated by the dashed arrow in FIG. 5(c). Specific examples of the material for the surface layer 3 include various functional paints, such as urethane paint, flocked paint, emulsion-based material, and vibration-damping paint, which are similar to the sound-absorbing material contained in the sound-absorbing layer 1. In addition to the above coating method, the surface layer 3 may be formed by hydraulic transfer or the like.

[0024] As described above, the acoustic control mat S of the embodiment comprises, when viewed from the speaker SP side, a surface layer 3, a sound absorbing layer 1 formed of sound absorbing materials with different densities and having wedge-shaped concave and convex regions 1B and 1A, respectively, and a vibration damping layer 2, thereby effectively realizing the functions (i) to (iii) above.

[0025] Next, the manufacturing process and manufacturing device for the sound control mat S of the embodiment will be described with reference to FIG.

[0026] That is, as shown in FIG. 6(a), the acoustic control mat S of the embodiment is manufactured through the following steps: a step of cutting a substrate containing the above-mentioned sound-absorbing material that will become the sound-absorbing layer 1 of the embodiment to the size and thickness of the sound-absorbing layer 1 (step S1); a step of molding / manufacturing the sound-absorbing layer 1 of the embodiment from the substrate by a hot press method (i.e., the sound-absorbing layer 1 having the recessed regions 1B and raised regions 1A with the characteristics / structures described above) (step S2); a step of applying a material that will become the surface layer 3 as paint to the surface of the molded / manufactured sound-absorbing layer 1 (i.e., the surface on which the recessed regions 1B and the raised regions 1A are formed) and drying it (step S3); and a step of bonding the vibration-damping layer 2 to the surface of the molded / manufactured sound-absorbing layer 1 opposite to the surface on which the surface layer 3 is applied (step S4). At this time, in the heat pressing process of step S2, as illustrated in Figure 6(b), a molding die MD having a surface shape that is, for example, a female mold for the shapes of the recessed regions 1B and the protruding regions 1A on the surface of the sound absorbing layer 1 is used to heat and press the substrate MT that will become the sound absorbing layer 1 (see the white arrow in Figure 6(b)).

[0027] The above-described hot pressing step (step S2) makes it possible to achieve a density difference in the sound absorbing material as the sound absorbing layer 1 of the embodiment, and to form a skin layer on the surface on which the surface layer 3 is formed.

[0028] As explained above, the structure of the sound control mat S of the embodiment includes a vibration-damping layer 2 and a sound-absorbing layer 1, with recessed areas 1B and raised areas 1A formed on the surface of the sound-absorbing layer 1 facing the speaker SP, and the density of the sound-absorbing material differs between the recessed areas 1B and the raised areas 1A, so that the difference in sound absorption effect due to the difference in density improves the sound absorption effect of the sound control mat S as a whole, thereby further improving sound quality. In other words, by eliminating the cause of sound quality degradation in the door D on which the speaker SP is installed (i.e., preventing a deterioration in sound quality), the sound quality when listening to sound emitted from the speaker SP is improved, and the functions (i) and (iii) above are improved.

[0029] Furthermore, since the surface layer 3 is further provided on the surface of the sound absorbing layer 1 facing the speaker SP, the effect of reflecting sound waves from the speaker SP can be improved, thereby improving the function (ii) above.

[0030] As a result of listening tests conducted by the inventors of the present application, the following auditory effects (A) to (D) were confirmed with respect to the above-mentioned effects.

[0031] (a) The low frequencies of the sound emitted from the speaker SP became tighter, giving it a sense of attack. (i) The sound has become thicker in the mid-low range, and the clarity of the mid-high range has improved. (c) Natural sound image positioning was achieved. (d) The sound has become more "glossy" and its texture has improved.

[0032] Furthermore, if the surface layer 3 and the sound-absorbing layer 1 are made of the same type of material, it is possible to simplify the manufacturing process for the acoustic control mat S. In the above-described embodiment, the surface layer 3 is formed by, for example, coating after the sound-absorbing layer 1 is manufactured, but alternatively, the heating temperature of the surface of the sound-absorbing layer 1 on the speaker SP side in the heat pressing step (see step S2 in Figure 6(a)) may be increased to melt the sound-absorbing material on that surface and make it into a thin film, and this thin film may be used as the surface layer 3 of the embodiment.

[0033] Furthermore, when the vibration-damping layer 2 is made of an elastic material, it is possible to effectively suppress vibrations of the outer panel OP caused by sound emitted from the speaker SP.

[0034] 6, recessed regions 1B and raised regions 1A are formed by a heat pressing process on the surface of the sound absorbing layer 1 of the sound control mat S located on the rear side of the speaker SP, resulting in a difference in the density of the sound absorbing material in the recessed regions 1B and the density of the sound absorbing material in the raised regions 1A. This difference in density results in a difference in sound absorption effect, which makes it possible to improve the sound absorption effect of the sound control mat S as a whole, and by eliminating the factors that deteriorate sound quality, the sound quality when listening to sound emitted from the speaker SP is improved, thereby improving the functions (i) and (iii) above. [Variations]

[0035] Next, modified examples corresponding to the embodiment will be described with reference to Figures 7 to 10. In each modified example, the same components as those in the sound control mat S of the example will be designated by the same component numbers, and detailed descriptions will be omitted.

[0036] (I) First Modification First, the first modified example will be described with reference to Fig. 7. Fig. 7 is a plan view showing the structure of the sound control mat of the first modified example.

[0037] The sound absorbing layer 10 constituting the sound control mat S1 of the first modified example has a surface shape in which recessed regions 10B and raised regions 10A are formed in parallel, as shown in Fig. 7, instead of the surface shape in the sound control mat S of the embodiment in which the wedge-shaped recessed regions 1B and raised regions 1A intersect at 45 degrees as shown in the plan view of Fig. 3(a). In this case, the difference in density between the sound absorbing material in raised regions 10A and the sound absorbing material in recessed regions 10B of the first modified example is the same as the difference in density between the sound absorbing material in raised regions 1A and the sound absorbing material in recessed regions 1B of the embodiment.

[0038] (II) Second Modification Next, a second modified example will be described with reference to Fig. 8. Fig. 8 is a plan view showing the structure of the sound control mat of the second modified example.

[0039] The sound absorbing layer 11 constituting the sound control mat S2 of the second modified example has a surface shape, instead of the surface shape of the sound control mat S of the embodiment, that includes raised areas 11A that are square in plan view and arranged in a staggered pattern, and recessed areas 11B that are (eventually) formed between the raised areas 11A, as shown in Fig. 8. In this case, the difference between the density of the sound absorbing material in the raised areas 11A of the second modified example and the density of the sound absorbing material in the recessed areas 11B is the same as the difference between the density of the sound absorbing material in the raised areas 1A of the embodiment and the density of the sound absorbing material in the recessed areas 11B.

[0040] (III) Third Modification Next, a third modified example will be described with reference to Fig. 9. Fig. 9 is a plan view and the like showing the structure of the sound control mat of the third modified example.

[0041] The sound absorbing layer 12 constituting the sound control mat S3 of the third modified example has a surface shape in which, instead of the surface shape of the sound control mat S of the embodiment, convex regions 12A with a triangle-shaped cross section and concave regions 12B formed between the convex regions 12A are formed in parallel, as shown in Fig. 9. In this case, the difference in density between the sound absorbing material in the convex regions 12A and the sound absorbing material in the concave regions 12B of the third modified example is similar to the difference in density between the sound absorbing material in the convex regions 1A and the sound absorbing material in the concave regions 12B of the embodiment.

[0042] (IV) Fourth Modification Finally, a fourth modified example will be described with reference to Fig. 10. Fig. 10 is a plan view showing the structure of the sound control mat of the fourth modified example.

[0043] The sound absorbing layer 13 constituting the sound control mat S4 of the fourth modified example has a surface shape in which, instead of the above-described surface shape of the sound control mat S of the embodiment, convex regions 13A whose overall (three-dimensional) shape is pyramidal (in other words, quadrangular pyramid) and concave regions 13B formed between the convex regions 13A are arranged in a checkerboard pattern, as shown in Fig. 10. In this case, the difference between the density of the sound absorbing material in the convex regions 13A and the density of the sound absorbing material in the concave regions 13B of the fourth modified example is the same as the difference between the density of the sound absorbing material in the convex regions 1A and the density of the sound absorbing material in the concave regions 13B of the embodiment.

[0044] The sound control mat S1 of the first modified example to the sound control mat S4 of the fourth modified example, which have the structure described above, can also achieve the functions (i) to (iii) above, similar to the sound control mat S of the embodiment. [Explanation of symbols]

[0045] 1, 10, 11, 12, 13 Sound absorbing layer 1A, 10A, 11A, 12A, 13A convex area 1B, 10B, 11B, 12B, 13B concave area 2. Vibration-damping layer 3 Surface layer S Acoustic control material (acoustic control mat) SP speaker

Claims

[Claim 1] An acoustic control member disposed on the rear side of a speaker and spaced apart from the rear side, a vibration-damping layer that suppresses vibrations that occur in a mounting member to which the acoustic control member is attached due to sound emitted from the speaker; and a sound absorbing layer laminated on the speaker side surface of the vibration damping layer and including a sound absorbing material; Equipped with a concave region having a concave shape as viewed from the speaker side and a convex region having a convex shape as viewed from the speaker side are formed on the surface of the sound absorbing layer facing the speaker, An acoustic control member, characterized in that the density of the sound absorbing material in the recessed areas is different from the density of the sound absorbing material in the protruding areas.

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