Sound absorbing and insulating structures

Abstract

To provide a highly reliable sound absorption and sound insulation structure that achieves stable sound absorption and sound insulation performance.SOLUTION: In a sound absorption and sound insulation structure formed as a wall by arranging a plurality of sound absorption and sound insulation structure unit parts 4 side by side along a plane, the sound absorption and sound insulation unit part 4 includes a first side 6, a second side 8 located opposite the first side, and three types of holes 9: holes 9N, holes 9J, and holes 9I. The holes 9N, holes 9J, and holes 9I are formed in the sound absorption and sound insulation structure unit part 4 along the same plane including the direction of thickness of the sound absorption and sound insulation structure, and are different in shape and length from each other. Also the sound absorption and sound insulation structure unit part 4 includes a cavity 30 and a cavity 32.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a sound absorbing and insulating structure. [Background technology]

[0002] Patent Document 1 discloses a lightweight soundproof structure having one or more soundproof cells. Each of the one or more soundproof cells includes a frame with a through hole, a membrane fixed to the frame, and an opening formed by one or more holes drilled in the membrane, with both ends of the through hole in the frame left unblocked. This soundproof structure also has a shielding peak frequency at which transmission loss is maximized and is determined by the openings of the one or more soundproof cells, lower than the first natural vibration frequency of the membrane of the one or more soundproof cells, and selectively attenuates sound in a certain frequency band centered on the shielding peak frequency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 136973 Summary of the Invention [Problem to be solved by the invention]

[0004] The soundproof structure described in Patent Document 1 is a structure that uses a membrane as described above, and therefore there is a concern that the sound absorption and blocking performance will change if the membrane is deformed or damaged, posing a reliability issue in achieving stable sound absorption and blocking performance.

[0005] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a highly reliable sound absorbing and insulating structure that can achieve stable sound absorbing and insulating performance. [Means for solving the problem]

[0006] In order to achieve the above object, a sound absorbing and insulating structure according to at least one embodiment of the present disclosure comprises: The first page and a second surface located opposite the first surface; a first hole that opens to the first surface and does not open to the second surface; a second hole that opens to the first surface and does not open to the second surface, the second hole having a different shape and length from the first hole; Equipped with. [Effects of the Invention]

[0007] According to at least one embodiment of the present disclosure, a highly reliable sound absorbing and insulating structure capable of achieving stable sound absorbing and insulating performance is provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a sound absorbing and insulating structure 2A according to one embodiment. [Figure 2] 2 is a schematic perspective view showing an example of the sound absorbing and insulating structure unit 4 shown in FIG. [Figure 3] 1 is a schematic cross-sectional view showing a cross section along the direction in which the three types of holes 9 in the sound absorbing and insulating structure unit 4 are arranged (a cross section including the axes of the three types of holes 9). [Figure 4] 4 is a graph showing an example of the sound absorbing performance of the sound absorbing and insulating structure 2A. [Figure 5] 4 is a graph showing an example of the sound insulation performance of the sound absorbing and insulating structure 2A. [Figure 6] FIG. 10 is a schematic perspective view of a sound absorbing and insulating structure 2B according to another embodiment. [Figure 7] 7 is a schematic perspective view showing an example of the internal structure of the sound absorbing and insulating structure layer 24 shown in FIG. 6. FIG. [Figure 8] FIG. 7 is a diagram showing an example of a cross section perpendicular to the axial direction of the sound absorbing and insulating structure 2B shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8. [Figure 10] 4 is a graph showing an example of the sound insulation performance of the sound absorbing and insulating structure 2B. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0010] Fig. 1 is a schematic perspective view of a sound absorbing and insulating structure 2A according to one embodiment. The sound absorbing and insulating structure 2A may be used to absorb and block (absorb and block) noise from a rotating body such as a fan, for example. In the exemplary embodiment shown in Fig. 1, the sound absorbing and insulating structure 2A is a wall-like structure formed along a plane, but the shape of the sound absorbing and insulating structure is not particularly limited, and may be configured, for example, in a box shape so as to cover the source of noise.

[0011] In the exemplary embodiment shown in Fig. 1, the sound absorbing and insulating structure 2A includes a planar first surface 6 and a planar second surface 8 located on the opposite side to the first surface 6 (the far side of the paper in Fig. 1), and the thickness of the sound absorbing and insulating structure 2A is determined by the first surface 6 and the second surface 8. The sound absorbing and insulating structure 2A has a plurality of holes 9 formed therein, each opening into the first surface 6. Each of the plurality of holes 9 opens only into the first surface 6 of the sound absorbing and insulating structure 2A, and does not open into the second surface 8.

[0012] 1, the sound absorbing and insulating structure 2A is formed into a wall shape by arranging a plurality of sound absorbing and insulating structure unit parts 4 along a plane, with the rectangular parallelepiped sound absorbing and insulating structure unit part 4 having three types of holes 9 formed as the smallest structural unit. Note that the plurality of sound absorbing and insulating structure unit parts 4 do not need to be configured as separate parts independent of each other, and the sound absorbing and insulating structure 2A may be integrally formed, for example, by a 3D printer or the like, or may be manufactured by combining a plurality of parts manufactured by machining or the like, and there are no particular restrictions on the method of manufacturing the sound absorbing and insulating structure 2A.

[0013] Fig. 2 is a schematic perspective view showing an example of the sound absorbing and insulating structure unit part 4 shown in Fig. 1. Fig. 3 is a schematic cross-sectional view showing a cross section along the direction in which the three types of holes 9 in the sound absorbing and insulating structure unit part 4 are arranged (a cross section including the axes of each of the three types of holes 9).

[0014] 2 and 3, the sound absorbing and insulating structure unit 4 includes the three types of holes 9: hole 9N, hole 9J, and hole 9I. The holes 9N, 9J, and 9I are formed inside the sound absorbing and insulating structure unit 4 along the same plane including the thickness direction of the sound absorbing and insulating structure 2A, and are different in shape and length from one another. Specifically, the length of hole 9N is different from the length of hole 9J, the length of hole 9J is different from the length of hole 9I, and the length of hole 9I is different from the length of hole 9N. Furthermore, the shape of hole 9N is different from the shape of hole 9J, the shape of hole 9J is different from the shape of hole 9I, and the shape of hole 9I is different from the shape of hole 9N.

[0015] The sound absorbing and insulating structure unit 4 includes a first surface 6a that constitutes a part of the first surface 6, and a second surface 8a that constitutes a part of the second surface 8 on the opposite side to the first surface 6a. One end of the hole 9N is formed as an open end 9N1 that opens to the first surface 6a, and the other end of the hole 9N is formed as a closed end 9N2 that closes inside the sound absorbing and insulating structure unit 4. One end of the hole 9J is formed as an open end 9J1 that opens to the first surface 6a, and the other end of the hole 9J is formed as a closed end 9J2 that closes inside the sound absorbing and insulating structure unit 4. One end of the hole 9I is formed as an open end 9I1 that opens to the first surface 6a, and the other end of the hole 9I is formed as a closed end 9I2 that closes inside the sound absorbing and insulating structure unit 4. Each of the holes 9N, 9J, and 9I is open only to the first surface 6a, and not to the second surface 8a. That is, each of the holes 9N, 9J, and 9I is open only to the first surface 6 and not to the second surface 8.

[0016] 2 and 3, for convenience, the normal direction of the first surface portion 6a (the normal direction of the first surface 6), i.e., the thickness direction of the sound absorbing and insulating structure 2A, is defined as the x direction, the direction perpendicular to the x direction and in which the holes 9J, 9I, and 9N in the sound absorbing and insulating structure unit portion 4 are aligned (more specifically, the direction in which the opening end 9J1 of the hole 9J, the opening end 9I1 of the hole 9I, and the opening end 9N1 of the hole 9N are aligned in the first surface portion 6a) is defined as the y direction, and the direction perpendicular to each of the x direction and the y direction is defined as the z direction. Note that in the illustrated example, the holes 9J, 9I, and 9N are aligned in this order along the y direction, but the order in which the holes 9J, 9I, and 9N are aligned is not limited to the illustrated example.

[0017] 3 (a cross section perpendicular to the z direction), hole 9N is formed in an N shape, hole 9J is formed in a J shape, and hole 9I is formed in an I shape (straight line). That is, the axis ON of hole 9N that defines the length of hole 9N extends in an N shape, the axis OJ of hole 9J that defines the length of hole 9J extends in a J shape, and the axis OI of hole 9I that defines the length of hole 9I extends in an I shape (straight line). In the illustrated exemplary embodiment, each of the axes ON, OJ, and OI extends along a plane perpendicular to the z direction.

[0018] The hole 9N includes a linear passage portion 9Na, a linear passage portion 9Nb, a linear passage portion 9Nc, a linear passage portion 9Nd, and a linear passage portion 9Ne as a plurality of passage portions connected in series. Each of the linear passage portion 9Na, the linear passage portion 9Nb, the linear passage portion 9Nc, the linear passage portion 9Nd, and the linear passage portion 9Ne is a cavity formed inside the sound absorbing and insulating structure unit 4. In the example shown in the figure, the cross section of the linear passage portion 9Na perpendicular to the x direction is quadrangular, the cross section of the linear passage portion 9Nb perpendicular to the y direction is quadrangular, the cross section of the linear passage portion 9Nc perpendicular to the x direction is quadrangular, the cross section of the linear passage portion 9Nd perpendicular to the y direction is quadrangular, and the cross section of the linear passage portion 9Ne perpendicular to the x direction is quadrangular.

[0019] One end of the linear passage portion 9Na opens to the first surface 6, and the linear passage portion 9Na extends from the first surface 6 toward the second surface 8 along the x direction (a direction intersecting with the first surface 6). An end of the linear passage portion 9Na on the second surface 8 side is connected to one end of the linear passage portion 9Nb. The linear passage portion 9Nb extends from the end of the linear passage portion 9Na on the second surface 8 side toward the hole 9I along the y direction (a direction intersecting with the extending direction of the linear passage portion 9Na). An end of the linear passage portion 9Nb opposite to the linear passage portion 9Na is connected to one end of the linear passage portion 9Nc. The linear passage portion 9Nc extends from the end of the linear passage portion 9Nb opposite to the linear passage portion 9Na toward the first surface 6 side along the x direction (a direction intersecting with the extending direction of the linear passage portion 9Nb). An end of the linear passage portion 9Nc on the first surface 6 side is connected to one end of the linear passage portion 9Nd. The linear passage portion 9Nd extends from the end of the linear passage portion 9Nc on the first surface 6 side toward the hole 9I along the y direction (a direction intersecting the extending direction of the linear passage portion 9Nc). An end of the linear passage portion 9Nd opposite the linear passage portion 9Nc is connected to an end of the linear passage portion 9Ne on the first surface 6 side. The linear passage portion 9Ne extends from the end of the linear passage portion 9Nd opposite the linear passage portion 9Nc toward the second surface 8 along the x direction (a direction intersecting the extending direction of the linear passage portion 9Nd). An end of the linear passage portion 9Ne on the second surface 8 side in the x direction is not open to the second surface 8 and is a closed end 9N2.

[0020] 2 and 3, the connection between the linear passage portion 9Na and the linear passage portion 9Nb forms a bend 9Nab where the direction in which the hole 9N extends changes by 90 degrees, and the connection between the linear passage portion 9Nb and the linear passage portion 9Nc forms a bend 9Nbc where the direction in which the hole 9N extends changes by 90 degrees. Also, the connection between the linear passage portion 9Nc and the linear passage portion 9Nd forms a bend 9Ncd where the direction in which the hole 9N extends changes by 90 degrees, and the connection between the linear passage portion 9Nd and the linear passage portion 9Ne forms a bend 9Nde where the direction in which the hole 9N extends changes by 90 degrees.

[0021] In this way, the hole 9N is composed of a linear passage portion 9Na, a linear passage portion 9Nb, a linear passage portion 9Nc, a linear passage portion 9Nd, and a linear passage portion 9Ne connected in series, and is formed in an N-shape in a cross section perpendicular to the z direction.

[0022] The hole 9J includes a linear passage portion 9Ja, a linear passage portion 9Jb, and a linear passage portion 9Jc as a plurality of passage portions connected in series. Each of the linear passage portion 9Ja, the linear passage portion 9Jb, and the linear passage portion 9Jc is a cavity formed inside the sound absorbing and insulating structure unit 4. In the example shown, the cross section of the linear passage portion 9Ja perpendicular to the x direction is quadrangular, the cross section of the linear passage portion 9Jb perpendicular to the y direction is quadrangular, and the cross section of the linear passage portion 9Jc perpendicular to the x direction is quadrangular.

[0023] One end of the linear passage portion 9Ja opens to the first surface 6, and the linear passage portion 9Ja extends from the first surface 6 toward the second surface 8 along the x direction. An end of the linear passage portion 9Ja on the second surface 8 side is connected to one end of the linear passage portion 9Jb. The linear passage portion 9Jb extends from the end of the linear passage portion 9Ja on the second surface 8 side toward the hole 9I along the y direction (a direction intersecting the extending direction of the linear passage portion 9Ja). An end of the linear passage portion 9Jb opposite to the linear passage portion 9Ja connects to an end of the linear passage portion 9Jc on the second surface 8 side. The linear passage portion 9Jc extends from the end of the linear passage portion 9Jb opposite to the linear passage portion 9Ja toward the first surface 6a along the x direction. An end of the linear passage portion 9Jc on the first surface 6 side in the x direction does not open to the first surface 6, but is a closed end 9J2.

[0024] In the example shown in Figures 2 and 3, the portion where the linear passage portion 9Ja and the linear passage portion 9Jb connect constitutes a bending portion 9Jab where the direction in which the hole 9J extends changes by 90 degrees, and the portion where the linear passage portion 9Jb and the linear passage portion 9Jc connect constitutes a bending portion 9Jbc where the direction in which the hole 9J extends changes by 90 degrees.

[0025] In this way, the hole 9J is constituted by the linear passage portion 9Ja, the linear passage portion 9Jb, and the linear passage portion 9Jc, and is formed in a J-shape in a cross section perpendicular to the z direction.

[0026] The hole 9I is a cavity formed inside the sound absorbing and insulating structure unit 4. The hole 9I is composed only of a linear passage portion 9Ia that extends linearly from the first surface 6 along the x direction. In the example shown, the cross section of the hole 9I perpendicular to the x direction is rectangular. One end of the hole 9I opens to the first surface 6, and the end of the hole 9I on the second surface 8 side does not open to the second surface 8 but is a closed end 9I2. The hole 9I is formed in an I-shape (linear) in the cross section perpendicular to the z direction.

[0027] In the above sound absorbing and insulating structure 2A, if the length of hole 9N is L1, the length of hole 9J is L2, and the length of hole 9I is L3, then L1 ≠ L2 ≠ L3 is satisfied, and L1, L2, and L3 are different lengths. For example, the length L1 of hole 9N may be approximately twice (e.g., 1.5 to 2.5 times) the length L2 of hole 9J, and the length L2 of hole 9J may be approximately twice (e.g., 1.5 to 2.5 times) the length L3 of hole 9I. Furthermore, the length L1 of hole 9N may be 1.8 to 2.2 times the length L2 of hole 9J, and the length L2 of hole 9J may be 1.8 to 2.2 times the length L3 of hole 9I.

[0028] 3, if the length of the axis ONa of the straight passage portion 9Na is LNa, the length of the axis of the straight passage portion 9Nb is LNb, the length of the axis ONc of the straight passage portion 9Nc is LNc, the length of the axis ONd of the straight passage portion 9Nd is LNd, and the length of the axis ONe of the straight passage portion 9Ne is LNe, the length L1 of the hole 9N is the sum of LNa, LNb, LNc, LNd, and LNe, and satisfies L1 = LNa + LNb + LNc + LNd + LNe. If the length of the axis OJa of the straight passage portion 9Ja is LJa, the length of the axis OJb of the straight passage portion 9Jb is LJb, and the length of the axis OJc of the straight passage portion 9Jc is LJc, the length L2 of the hole 9J is the sum of LJa, LJb, and LJc, and satisfies L2 = LJa + LJb + LJc. The length L3 of the hole 9I is the length of the axis OI of the linear passage portion 9Ia.

[0029] 2 and 3, the sound absorbing and insulating structure unit portion 4 includes a cavity 30 and a cavity 32. The cavity 30 is formed between the linear passage portion 9Ja and the linear passage portion 9Ia, between the closed end 9J2 of the linear passage portion 9Jc and the first surface 6. The cavity 32 is formed between the linear passage portion 9Jc and the linear passage portion 9Ne, between the closed end 9I2 of the linear passage portion 9Ia and the second surface 8.

[0030] In comparison with the soundproof structure described in Patent Document 1, the above-described sound absorbing and insulating structure 2A can obtain a sound absorbing and insulating effect by using a plurality of holes 9 of different lengths and shapes without using a membrane, and therefore can provide a highly reliable sound absorbing and insulating structure 2A that can achieve stable sound absorbing and insulating performance.

[0031] Furthermore, according to the sound absorbing and insulating structure 2A, the target frequencies (frequencies at which the sound absorption coefficient is maximized) for sound absorption and insulating in each of the holes 9N, 9J, and 9I can be made different from one another, and these three types of holes 9N, 9J, and 9I can achieve high sound absorbing and insulating performance at frequencies including the higher order components of the rotating body (1st to 6th, 7th, 9th, etc.).

[0032] For each of the plurality of holes 9 formed in the sound absorbing and insulating structure 2A, the length L of the hole 9 and the target frequency f of the hole 9 arer The relationship between the frequency at which the sound absorption coefficient is maximized and the sound absorption coefficient is maximized can be expressed by the following formula (A). f r =(2n+1)×c0×n / (4L) …(A) where n is a natural number and c0 is the speed of sound in standard atmosphere.

[0033] For this reason, for hole 9N, if the length L1 of hole 9N is, for example, approximately 85 mm and substituted for L in formula (A), the target frequencies fr for hole 9N will be approximately 1 kHz, approximately 3 kHz, approximately 5 kHz, etc. For hole 9J, if the length L2 of hole 9J is, for example, approximately 43 mm and substituted for L in formula (A), the target frequencies fr for hole 9J will be approximately 2 kHz, approximately 6 kHz, approximately 10 kHz, etc. For hole 9I, if the length L3 of hole 9I is, for example, approximately 21 mm and substituted for L in formula (A), the target frequencies fr for hole 9I will be approximately 4 kHz, approximately 12 kHz, approximately 20 kHz, etc. In practice, due to interactions between multiple holes 9 caused by sound pressure or the like, the relationship between the length L of hole 9 and the target frequencies fr may deviate slightly from that defined by formula (A). In such cases, the lengths of holes 9N, 9J, and 9I may be fine-tuned as appropriate.

[0034] Fig. 4 is a graph showing an example of the sound absorption performance of the sound absorbing and insulating structure 2A, showing an example of the relationship between frequency and sound absorption coefficient in the sound absorbing and insulating structure 2A. Fig. 5 is a graph showing an example of the sound insulating performance of the sound absorbing and insulating structure 2A, showing an example of the relationship between frequency and sound transmission loss in the sound absorbing and insulating structure 2A. The examples shown in Figs. 4 and 5 show the sound absorption performance and sound insulating performance of the sound absorbing and insulating structure 2A when the thickness of the sound absorbing and insulating structure 2A (i.e., the distance between the first surface 6 and the second surface 8) is approximately 30 mm, the length L1 of the hole 9N is approximately 85 mm, the length L2 of the hole 9J is approximately 43 mm, and the length L3 of the hole 9I is approximately 21 mm. Note that the comparative example in Fig. 5 shows the sound transmission loss of the sound absorbing and insulating structure when the sound absorbing and insulating structure 2A does not have multiple holes 9.

[0035] As shown in Figures 4 and 5, the sound absorbing and insulating structure 2A, by providing holes 9N, 9J, and 9I, can achieve high sound absorbing and insulating performance for target frequencies including higher order components (1st to 6th, 7th, 9th, ...) of a rotating body such as a fan (approximately 1 kHz, approximately 2 kHz, approximately 3 kHz, approximately 4 kHz, approximately 5 kHz, approximately 6 kHz, approximately 7 kHz, approximately 9 kHz, ... in the illustrated example).

[0036] For example, in the case of the soundproof structure described in Patent Document 1, if one were to attempt to achieve a sound absorption and blocking effect up to the higher-order components of a rotating body, it would be necessary to provide many types of soundproof cells with different membrane rigidities, etc., and in a limited space, the number of soundproof cells corresponding to each target frequency would tend to be small, and the overall dimensions of the soundproof structure would tend to be large to achieve a sufficient sound absorption and blocking effect. In contrast, the above-mentioned sound absorbing and blocking structure 2A can achieve sound absorption and blocking effects for sounds of many target frequencies with a small number of types of holes 9 (three types of holes 9N, 9J, and 9I in the illustrated example), so it is possible to increase the number of holes 9 corresponding to each target frequency even in a limited space. As a result, it is possible to achieve a high sound absorption and blocking effect for frequencies including the higher-order components of a rotating body while suppressing an increase in the size of the sound absorbing and blocking structure 2A.

[0037] Fig. 6 is a schematic perspective view of a sound absorbing and insulating structure 2B according to another embodiment. In the exemplary embodiment shown in Fig. 6, the sound absorbing and insulating structure 2B has a cylindrical shape. In Fig. 6, the outline of the outer surface of the cylindrical sound absorbing and insulating structure 2B is shown by a dashed dotted line, and the cavity formed inside the sound absorbing and insulating structure 2B is shown by a solid line.

[0038] In the following, unless otherwise specified, "axial direction" means the axial direction in the cylindrical shape of the sound absorbing and insulating structure 2B, "circumferential direction" means the circumferential direction in the cylindrical shape, and "radial direction" means the radial direction in the cylindrical shape, unless otherwise specified.

[0039] As shown in Figure 6, the sound absorbing and insulating structure 2B includes an outer peripheral surface 12 (second surface), an inner peripheral surface 14 (first surface) located radially opposite the outer peripheral surface 12, one end surface 16 which is an end surface on one end side in the axial direction, and another end surface 18 which is an end surface on the other end side in the axial direction.

[0040] The sound absorbing and insulating structure 2B has a plurality of holes 20 formed therein, which open to the inner peripheral surface 14. Each of the plurality of holes 20 opens only to the inner peripheral surface 14 of the sound absorbing and insulating structure 2B, and does not open to any surfaces of the sound absorbing and insulating structure 2B other than the inner peripheral surface (the outer peripheral surface 12, the one end surface 16, and the other end surface 18).

[0041] In the exemplary embodiment shown in Fig. 6, the sound absorbing and insulating structure 2B is configured as an assembly of multiple sound absorbing and insulating structure unit parts 22. The sound absorbing and insulating structure 2B has 20 sound absorbing and insulating structure layers 24 arranged in the axial direction, with each sound absorbing and insulating structure layer 24 consisting of a set of four sound absorbing and insulating structure unit parts 22 arranged in the circumferential direction, resulting in an integrated configuration of 80 sound absorbing and insulating structure unit parts 22. Note that each of the multiple sound absorbing and insulating structure unit parts 22 does not need to be configured as separate parts independent of each other, and each of the multiple sound absorbing and insulating structure layers 24 does not need to be configured as separate parts independent of each other. The sound absorbing and insulating structure 2B may be integrally formed, for example, by a 3D printer or the like, or may be manufactured by combining multiple parts manufactured by machining or the like; there are no particular limitations on the method of manufacturing the sound absorbing and insulating structure 2B.

[0042] Fig. 7 is a schematic perspective view showing an example of the internal structure of the sound absorbing and insulating structure layer 24 shown in Fig. 6. Fig. 8 is a view showing an example of a cross section perpendicular to the axial direction of the sound absorbing and insulating structure 2B shown in Fig. 6. Fig. 9 is a view showing the AA cross section in Fig. 8.

[0043] 6 to 8, the sound absorbing and insulating structure unit 22 includes three types of holes 20 constituting the plurality of holes 20: holes 20E, 20F, and 20G. The holes 20E, 20F, and 20G are formed inside the sound absorbing and insulating structure unit 22 so as to extend along a plane perpendicular to the axial direction, and are different in shape and length from one another. Specifically, the length of the hole 20E is different from the length of the hole 20F, the length of the hole 20F is different from the length of the hole 20G, and the length of the hole 20G is different from the length of the hole 20E. Furthermore, the shape of the hole 20E is different from the shape of the hole 20F, the shape of the hole 20F is different from the shape of the hole 20G, and the shape of the hole 20G is different from the shape of the hole 20E.

[0044] 7 to 9, the sound absorbing and insulating structure unit 22 includes an inner peripheral surface 14a that constitutes part of the inner peripheral surface 14, and an outer peripheral surface 12a that constitutes part of the outer peripheral surface 12 on the opposite side to the inner peripheral surface 14a. One end of the hole 20E is formed as an open end 20E1 that opens to the inner peripheral surface 14a, and the other end of the hole 20E is formed as a closed end 20E2 that closes inside the sound absorbing and insulating structure unit 22. One end of the hole 20F is formed as an open end 20F1 that opens to the inner peripheral surface 14a, and the other end of the hole 20F is formed as a closed end 20F2 that closes inside the sound absorbing and insulating structure unit 22. One end of the hole 20G is formed as an open end 20G1 that opens to the inner peripheral surface 14a, and the other end of the hole 20G is formed as a closed end 20G2 that closes inside the sound absorbing and insulating structure unit 22. Each of the holes 20E, 20F, and 20G is open only to the inner circumferential surface portion 14a, and not to the outer circumferential surface portion 12a. That is, each of the holes 20E, 20F, and 20G is open only to the inner circumferential surface 14, and not to the outer circumferential surface 12.

[0045] 7 and 8, the hole 20E includes a straight passage portion 20Ea, an arcuate passage portion 20Eb, a straight passage portion 20Ec, and an arcuate passage portion 20Ed as a plurality of passage portions connected in series. Each of the straight passage portion 20Ea, the arcuate passage portion 20Eb, the straight passage portion 20Ec, and the arcuate passage portion 20Ed is a cavity formed inside the sound absorbing and insulating structure unit 4, and in the example shown, the cross section perpendicular to the radial direction of each of the straight passage portions 20Ea and 20Ec is quadrangular, and the cross section perpendicular to the circumferential direction of each of the arcuate passage portions 20Eb and 20Ed is quadrangular.

[0046] The radially inner end of the straight passage portion 20Ea opens to the inner circumferential surface 14, and the straight passage portion 20Ea extends radially outward from the inner circumferential surface 14. The radially outer end of the straight passage portion 20Ea connects to one circumferential end of the arc-shaped passage portion 20Eb. The arc-shaped passage portion 20Eb extends from the radially outer end of the straight passage portion 20Ea along the circumferential direction (a direction intersecting the extending direction of the straight passage portion 20Ea) and connects to the radially outer end of the straight passage portion 20Ec. The straight passage portion 20Ec extends radially inward from the end of the arc-shaped passage portion 20Eb opposite to the straight passage portion 20Ea along the radial direction. The radially inner end of the straight passage portion 20Ec (the end of the straight passage portion 20Ec opposite the straight passage portion 20Eb) is connected to one circumferential end of the arcuate passage portion 20Ed. The arcuate passage portion 20Ed extends from the radially inner end of the straight passage portion 20Ec along the circumferential direction toward the straight passage portion 20Ea. The other circumferential end of the arcuate passage portion 20Ed is a closed end 20E2 that is not open.

[0047] In the illustrated example, the portion where the straight passage portion 20Ea and the arc-shaped passage portion 20Eb are connected forms a bending portion 20Eab where the direction in which the hole 20E extends bends by 90 degrees, the portion where the arc-shaped passage portion 20Eb and the straight passage portion 20Ec are connected forms a bending portion 20Ebc where the direction in which the hole 20E extends bends by 90 degrees, and the portion where the straight passage portion 20Ec and the arc-shaped passage portion 20Ed are connected forms a bending portion 20Ecd where the direction in which the hole 20E extends bends by 90 degrees.

[0048] The hole 20F is located between the hole 20E and the hole 20G, and includes a straight passage portion 20Fa and an arc-shaped passage portion 20Fb as a plurality of passage portions connected in series. Each of the straight passage portion 20Fa and the arc-shaped passage portion 20Fb is a cavity formed inside the sound absorbing and insulating structure unit 4. In the example shown, the cross section of the straight passage portion 20Fa perpendicular to the radial direction is quadrangular, and the cross section of the arc-shaped passage portion 20Fb perpendicular to the circumferential direction is quadrangular.

[0049] The straight passage portion 20Fa is located between the straight passage portion 20Ea of the hole 20E and the straight passage portion 20Ga of the hole 20G. A radially inner end of the straight passage portion 20Fa opens to the inner circumferential surface 14, and the straight passage portion 20Fa extends radially outward from the inner circumferential surface 14. The length of the straight passage portion 20Fa is shorter than the length of the straight passage portion 20Ea. A radially outer end of the straight passage portion 20Fa connects to one circumferential end of the arc-shaped passage portion 20Fb. The arc-shaped passage portion 20Fb is located radially inside the arc-shaped passage portion 20Eb of the hole 20E. The arc-shaped passage portion 20Fb extends from the radially outer end of the linear passage portion 20Fa in the circumferential direction (a direction intersecting the extending direction of the linear passage portion 20Fa) toward the arc-shaped passage portion 20Ed of the hole 20E. The other circumferential end of the arc-shaped passage portion 20Fb is a closed end 20F2 that is not open. In the illustrated example, the arc-shaped passage portion 20Ed of the hole 20E and the arc-shaped passage portion 20Fb of the hole 20F are formed in different circumferential ranges at the same radial position.

[0050] In the illustrated example, the portion where the linear passage portion 20Fa and the arcuate passage portion 20Fb are connected constitutes a bent portion 20Fab where the direction in which the hole 20F extends is bent by 90 degrees.

[0051] The hole 20G includes a straight passage portion 20Ga and an arc-shaped passage portion 20Gb connected in series. Each of the straight passage portion 20Ga and the arc-shaped passage portion 20Gb is a cavity formed inside the sound absorbing and insulating structure unit 4. In the example shown, the cross section of the straight passage portion 20Ga perpendicular to the radial direction is quadrangular, and the cross section of the arc-shaped passage portion 20Gb perpendicular to the circumferential direction is quadrangular.

[0052] The radially inner end of the linear passage portion 20Ga opens to the inner circumferential surface 14, and the linear passage portion 20Ga extends radially from the inner circumferential surface 14 toward the radially outer side. The length of the linear passage portion 20Ga is shorter than the length of the linear passage portion 20Fa. The radially outer end of the linear passage portion 20Ga connects to one circumferential end of the arcuate passage portion 20Gb. The arcuate passage portion 20Gb is located radially inside the arcuate passage portion 20Ed of the hole 20E and the arcuate passage portion 20Fb of the hole 20F. The arcuate passage portion 20Gb extends from the radially outer end of the linear passage portion 20Ga toward the linear passage portion 20Ga of the hole 20E along the circumferential direction (a direction intersecting the extending direction of the linear passage portion 20Ga). The other circumferential end of the arc-shaped passage portion 20Gd is a closed end 20F2 and is not open. In the illustrated example, the straight passage portion 20Ga and the straight passage portion 20Ec are located at the same position in the circumferential direction, and the straight passage portion 20Ga is located inside the straight passage portion 20Ec in the radial direction. Furthermore, at least a portion of the range in the circumferential direction in which the arc-shaped passage portion 20Gb is provided overlaps with at least a portion of the range in the circumferential direction in which the arc-shaped passage portion 20Ed of the hole 20E is provided.

[0053] In the illustrated example, the portion where the linear passage portion 20Ga and the arcuate passage portion 20Gb are connected constitutes a bent portion 20Gab where the direction in which the hole 20G extends is bent by 90 degrees.

[0054] In the sound absorbing and insulating structure 2B, if the length of hole 20E is L1, the length of hole 20F is L2, and the length of hole 20G is L3, then L1 ≠ L2 ≠ L3 is satisfied, and L1, L2, and L3 are different lengths. For example, the length L1 of hole 20E may be approximately twice the length L2 of hole 20F (e.g., 1.5 to 2.5 times), and the length L2 of hole 20F may be approximately twice the length L3 of hole 20G (e.g., 1.5 to 2.5 times). Furthermore, the length L1 of hole 20E may be 1.8 to 2.2 times the length L2 of hole 20F, and the length L2 of hole 20F may be 1.8 to 2.2 times the length L3 of hole 20G.

[0055] 8, if the length of the axis OEa of the straight passage portion 20Ea is LEa, the length of the axis of the arcuate passage portion 20Eb is LEb, the length of the axis OEc of the straight passage portion 20Ec is LEc, and the length of the axis OEd of the arcuate passage portion 20Ed is LEd, the length L1 of the hole 20E is the sum of LEa, LEb, LEc, and LEd, and satisfies L1 = LEa + LEb + LEc + LEd. If the length of the axis OFa of the straight passage portion 20Fa is LFab, and the length of the axis OFb of the arcuate passage portion 20Fb is LFa, the length L2 of the hole 20F is the sum of LFab and LFb, and satisfies L2 = LFa + LFb. When the length of the axis OGa of the straight passage portion 20Ga is LGa and the length of the axis OGb of the arcuate passage portion 20Gb is LGb, the length L3 of the hole 20G is the sum of LGa and LGb, and satisfies L3=LGa+LGb.

[0056] 7 and 8, the sound absorbing and insulating structure unit 4 includes a cavity 34 and a cavity 36 between the holes 20F and 20G. The cavity 34 is formed between the linear passage portion 20Fa and the linear passage portion 20Ga. The cavity 36 is formed at a position between the cavity 34 and the arcuate passage portion 20Fb in the radial direction and at a position between the linear passage portion 20Fa and the arcuate passage portion 20Gb in the circumferential direction.

[0057] In comparison with the soundproof structure described in Patent Document 1, the sound absorbing and insulating structure 2B described above can obtain a sound absorbing and insulating effect by using a plurality of holes 9 of different lengths and shapes without using a membrane, and therefore can provide a highly reliable sound absorbing and insulating structure that can achieve stable sound absorbing and insulating performance.

[0058] For each of the plurality of holes 20 formed in the sound absorbing and insulating structure 2B, the length L of the hole 20 and the target frequency f of the hole 20 are r The relationship between the frequency at which the sound absorption coefficient is maximized and the sound absorption coefficient is maximized can be expressed by the above formula (A).

[0059] Fig. 10 is a graph showing an example of the sound insulation performance of the sound absorbing and insulating structure 2B, showing an example of the relationship between frequency and sound transmission loss in the sound absorbing and insulating structure 2B. In the embodiment shown in Fig. 10, the sound insulation performance of the sound absorbing and insulating structure 2B for a sine sweep signal is shown for a case in which the length L1 of the hole 20E is approximately 85 mm, the length L2 of the hole 20F is approximately 43 mm, and the length L3 of the hole 20G is approximately 21 mm. Note that the comparative example in Fig. 10 shows the sound insulation performance of the sound absorbing and insulating structure for a sine sweep signal for a case in which the sound absorbing and insulating structure 2B does not have multiple holes 20.

[0060] As shown in FIG. 10, the sound absorbing and insulating structure 2B, by providing holes 20E, 20F, and 20G, can achieve high sound absorbing and insulating performance with frequencies including higher order components (1st to 6th, 7th, 9th, ...) of a rotating body such as a fan as target frequencies (1 kHz, 2 kHz, 3 kHz, 4 kHz, 5 kHz, 6 kHz, 7 kHz, 9 kHz, ... in the illustrated example).

[0061] According to the sound absorbing and insulating structure 2B, similar to the sound absorbing and insulating structure 2A, sound absorbing and insulating effects can be obtained for sounds of many target frequencies with a small number of types of holes 9 (three types of holes 20E, 20F, and 20G in the illustrated example), so that the number of holes 20 corresponding to each target frequency can be increased even in a limited space. Therefore, a high sound absorbing and insulating effect can be obtained for frequencies including high-order components of a rotating body while suppressing an increase in the size of the sound absorbing and insulating structure 2B.

[0062] Furthermore, while noise passes from one axial end side of the cylindrical sound absorbing and insulating structure 2B to the inner circumferential surface 14 side of the sound absorbing and insulating structure 2B, the noise can be effectively reduced by the holes 20E, 20F, and 20G formed on the inner circumferential surface 14. For this reason, by providing the sound absorbing and insulating structure 2B at an opening of a casing or the like that covers a rotating body that is the target for noise reduction, the noise emitted from the opening can be effectively reduced.

[0063] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0064] For example, in some of the above-described embodiments, the sound absorbing and insulating structure has three types of holes (first hole, second hole, and third hole) with different shapes and lengths, but the number of types of holes provided in the sound absorbing and insulating structure is not limited to three, and may be, for example, two types, or four or more types.

[0065] The contents described in each of the above embodiments can be understood, for example, as follows.

[0066] (1) The sound absorbing and insulating structure according to at least one embodiment of the present disclosure (for example, the above-described sound absorbing and insulating structures 2A and 2B) has the following features: A first surface (for example, the first surface 6 and the inner peripheral surface 14 described above), a second surface (for example, the second surface 8 or the outer peripheral surface 12) located opposite the first surface; First holes (for example, the above-mentioned holes 9N, 9J, 9I, holes 20E, 20F, and 20G) that open to the first surface and do not open to the second surface; a second hole that is open to the first surface and not open to the second surface and has a shape and length different from those of the first hole (for example, a hole other than the first hole among the above-mentioned holes 9N, 9J, 9I, 20E, 20F, and 20G); Equipped with.

[0067] According to the sound absorbing and insulating structure described in (1) above, each of the first and second holes is open to the first surface but not to the second surface, and therefore sound waves propagating through each of the first and second holes are reflected at the fixed end. Here, since the first and second holes have different shapes and lengths, sound absorbing and insulating effects can be obtained for different frequencies, and high sound absorbing and insulating performance can be achieved for frequencies including higher-order components of a rotating body such as a fan. Furthermore, compared to the soundproof structure described in Patent Document 1, sound absorbing and insulating effects can be obtained using the first and second holes that have different shapes and lengths without using a membrane, and therefore a highly reliable sound absorbing and insulating structure that can achieve stable sound absorbing and insulating performance can be provided. Furthermore, for example, in the case of the soundproof structure described in Patent Document 1, if one were to attempt to achieve a sound absorption and blocking effect up to the higher-order components of a rotating body, it would be necessary to provide many types of soundproof cells with different membrane rigidities, etc., and in a limited space, the number of soundproof cells corresponding to each target frequency would tend to be small, and the overall dimensions of the soundproof structure would tend to increase in order to achieve a sufficient sound absorption and blocking effect. In contrast, the sound absorbing and blocking structure described in (1) above can achieve sound absorption and blocking effects for sounds of many target frequencies with a small number of types of holes, so it is possible to increase the number of holes corresponding to each target frequency even in a limited space. As a result, it is possible to achieve a high sound absorption and blocking effect for frequencies including the higher-order components of a rotating body while suppressing an increase in the size of the sound absorbing and blocking structure.

[0068] (2) In some embodiments, in the sound absorbing and insulating structure described in (1) above, The first hole (for example, any of the above-mentioned holes 9N, 9J, holes 20E, 20F, and 20G) includes at least one bend portion (for example, the above-mentioned bend portions 9Nab, 9Nbc, 9Ncd, 9Nde, 9Jab, 9Jbc, 20Eab, 20Ebc, 20Ecd, 20Fab, and 20Gab) in which the direction in which the first hole extends changes.

[0069] According to the sound absorbing and insulating structure described in (2) above, since the first hole includes at least one bent portion, it is easy to ensure the length of the first hole even if the thickness from the first surface to the second surface of the sound absorbing and insulating structure is small, and compared to when the first hole is composed of only one straight passage portion that does not include a bent portion, it is possible to obtain a sound absorbing and insulating effect targeting relatively low frequencies while suppressing an increase in the thickness from the first surface to the second surface of the sound absorbing and insulating structure.

[0070] (3) In some embodiments, in the sound absorbing and insulating structure described in (2) above, the first holes (e.g., the above-mentioned holes 9N, 9J, and 20E) include at least two bends (e.g., the above-mentioned bends 9Nab, 9Nbc, 9Ncd, 9Nde, 9Jab, 9Jbc, 20Eab, 20Ebc, and 20Ecd) at which the extending direction of the first holes changes; the second hole (for example, any of the above-mentioned holes 9N, 9J, 20F, and 20G other than the first hole) includes at least one bent portion (for example, the above-mentioned bent portions 9Nab, 9Nbc, 9Ncd, 9Nde, 9Jab, 9Jbc, 20Fab, and 20Gab) in which the extending direction of the second hole changes, The number of the bent portions included in the first hole is different from the number of the bent portions included in the second hole.

[0071] According to the sound absorbing and insulating structure described in (3) above, the first hole includes at least two bends and the second hole includes at least one bend, so that even if the thickness of the sound absorbing and insulating structure from the first surface to the second surface is small, it is easy to ensure the length of the first hole and the second hole, and compared to, for example, a case where the first hole and the second hole are configured only by a single linear passage portion that does not include any bends, it is possible to obtain a sound absorbing and insulating effect targeting relatively low frequencies while suppressing an increase in the thickness of the sound absorbing and insulating structure from the first surface to the second surface.

[0072] (4) In some embodiments, in the sound absorbing and insulating structure according to any one of (1) to (3) above, The length of the first hole is 1.5 times or more and 2.5 times or less than the length of the second hole.

[0073] According to the sound absorbing and insulating structure described in (4) above, by making the length of the first hole about twice the length of the second hole (i.e., 1.5 to 2.5 times), it is possible to achieve high sound absorbing and insulating performance for target frequencies that include high-order components of a rotating body such as a fan.

[0074] (5) In some embodiments, in the sound absorbing and insulating structure according to any one of (1) to (4) above, The device further includes a third hole that opens to the first surface and does not open to the second surface, and that has a shape and length different from those of the first and second holes (for example, any of the above-mentioned holes 9N, 9J, 9I, 20E, 20F, and 20G excluding the first and second holes).

[0075] According to the sound absorbing and insulating structure described in (5) above, the target frequencies at which the sound absorbing and insulating effect can be obtained can be further increased in the sound absorbing and insulating structures described in (1) to (4) above.

[0076] (6) In some embodiments, in the sound absorbing and insulating structure described in (5) above, The length of the first hole (e.g., the above-mentioned holes 9N and 20E) is 1.5 to 2.5 times the length of the second hole (e.g., the above-mentioned holes 9J and 20F), and the length of the second hole is 1.5 to 2.5 times the length of the third hole (e.g., the above-mentioned holes 9I and 20G).

[0077] According to the sound absorbing and insulating structure described in (6) above, by making the length of the first hole about twice the length of the second hole (i.e., 1.5 to 2.5 times), and making the length of the second hole about twice the length of the third hole (i.e., 1.5 to 2.5 times), it is possible to achieve high sound absorbing and insulating performance for target frequencies that include high-order components of a rotating body such as a fan.

[0078] (7) In some embodiments, in the sound absorbing and insulating structure according to any one of (1) to (6) above, The first hole and the second hole extend along the same plane.

[0079] According to the sound absorbing and insulating structure described in (7) above, by forming the first holes and the second holes to extend along the same plane, it becomes easy to arrange the first holes and the second holes periodically and increase their number density.

[0080] (8) In some embodiments, in the sound absorbing and insulating structure according to any one of (1) to (7) above, the first hole includes a plurality of passages connected in series; The plurality of passages include: a first passage portion (for example, the above-mentioned linear passage portion 9Na, 9Ja, 20Ea) that opens to the first surface and extends from the first surface toward the second surface along a direction intersecting the first surface; a second passage portion (for example, the above-mentioned linear passage portion 9Nb, 9Jb or arcuate passage portion 20Eb) extending from an end portion of the first passage portion on the second surface side along a direction intersecting with the extending direction of the first passage portion; a third passage portion (for example, the above-mentioned linear passage portion 9Nc, 9Jc, 20Ec) extending from an end of the second passage portion opposite to the first passage portion toward the first surface side along a direction intersecting the extending direction of the second passage portion; Includes.

[0081] According to the sound absorbing and insulating structure described in (8) above, it is easy to ensure the length of the first hole even if the thickness from the first surface to the second surface of the sound absorbing and insulating structure is small, and compared to when the first hole is composed of only one straight passage portion that does not include a bend, it is possible to obtain a sound absorbing and insulating effect targeting relatively small frequencies while suppressing an increase in the thickness from the first surface to the second surface of the sound absorbing and insulating structure.

[0082] (9) In some embodiments, in the sound absorbing and insulating structure described in (8) above, The plurality of passages include: a fourth passage portion (for example, the above-mentioned linear passage portion 9Nd) extending from an end portion of the third passage portion on the first surface side along a direction intersecting with the extending direction of the third passage portion; a fifth passage portion (for example, the above-described linear passage portion 9Ne) extending from an end portion of the fourth passage portion opposite to the fourth passage portion toward the second surface side along a direction intersecting the extending direction of the fourth passage portion; Includes.

[0083] According to the sound absorbing and insulating structure described in (9) above, it is easy to ensure the length of the first hole even if the thickness from the first surface to the second surface of the sound absorbing and insulating structure is small, and compared to when the first hole is composed of only one straight passage portion that does not include a bend, it is possible to obtain a sound absorbing and insulating effect targeting relatively small frequencies while suppressing an increase in the thickness from the first surface to the second surface of the sound absorbing and insulating structure.

[0084] (10) In some embodiments, in the sound absorbing and insulating structure described above in (9), the second hole includes a plurality of passages connected in series; The plurality of passages of the second hole are a sixth passage portion (for example, the above-mentioned linear passage portion 9Ja) that opens to the first surface and extends from the first surface toward the second surface along a direction intersecting the first surface; a seventh passage portion (for example, the above-mentioned linear passage portion 9Jb) extending from an end portion of the sixth passage portion on the second surface side along a direction intersecting with the extending direction of the first passage portion; an eighth passage portion (for example, the above-mentioned linear passage portion 9Jc) extending from an end of the seventh passage portion opposite to the sixth passage portion toward the first surface side along a direction intersecting the extending direction of the sixth passage portion; Includes.

[0085] According to the sound absorbing and insulating structure described in (10) above, it is easy to ensure the length of the second hole even if the thickness from the first surface to the second surface of the sound absorbing and insulating structure is small, and compared to when the second hole is composed of only one straight passage portion that does not include a bent portion, it is possible to obtain a sound absorbing and insulating effect targeting relatively small frequencies while suppressing an increase in the thickness from the first surface to the second surface of the sound absorbing and insulating structure.

[0086] (11) In some embodiments, in the sound absorbing and insulating structure described in (10) above, A cavity (for example, cavity 30 described above) is included between the eighth passage portion and the first surface.

[0087] According to the sound absorbing and insulating structure described in (11) above, a cavity can be provided in the dead space that does not directly contribute to the sound absorbing and insulating effect in the configuration described in (10) above, thereby making it possible to reduce the weight of the sound absorbing and insulating structure.

[0088] (12) In some embodiments, in the sound absorbing and insulating structure described in (5) or (6) above, A cavity (for example, cavity 32 described above) is included between the third hole and the second surface.

[0089] According to the sound absorbing and insulating structure described in (12) above, a cavity can be provided in the dead space that does not directly contribute to the sound absorbing and insulating effect in the configuration described in (5) or (6) above, thereby making it possible to reduce the weight of the sound absorbing and insulating structure.

[0090] (13) In some embodiments, in the sound absorbing and insulating structure according to any one of (1) to (8) above, The sound absorbing and insulating structure is formed in a cylindrical shape, the first surface is the inner peripheral surface of the sound absorbing and insulating structure (for example, the above-mentioned inner peripheral surface 14), and the second surface is the outer peripheral surface of the sound absorbing and insulating structure (for example, the above-mentioned outer peripheral surface 12).

[0091] According to the sound absorbing and insulating structure described in (13) above, while noise passes from one axial end side of the cylindrical sound absorbing and insulating structure to the inner peripheral surface side of the sound absorbing and insulating structure, the noise can be effectively reduced by the first hole and the second hole described in (1) to (8) above formed on the inner peripheral surface. Therefore, by providing the sound absorbing and insulating structure in an opening of a casing or the like that covers a device that is the target of noise reduction, the noise emitted from the opening can be effectively reduced.

[0092] (14) In some embodiments, in the sound absorbing and insulating structure described in (13) above, the first hole includes a plurality of passages connected in series; The plurality of passages include: a first passage portion (for example, the above-mentioned linear passage portions 20Ea, 20Fa, 20Ga) extending from the inner circumferential surface toward the outside in the radial direction of the sound absorbing and insulating structure; a second passage portion (for example, the above-mentioned arc-shaped passage portions 20Eb, 20Fb, 20Gb) extending from the radially outer end of the first passage portion along the circumferential direction of the sound absorbing and insulating structure; Includes.

[0093] According to the sound absorbing and insulating structure described in (14) above, the length of the first hole can be easily ensured even if the thickness from the inner peripheral surface to the outer peripheral surface of the cylindrical sound absorbing and insulating structure is small, and compared to a case where the first hole is composed of only one straight passage portion that does not include a bent portion, it is possible to suppress an increase in the thickness from the inner peripheral surface to the outer peripheral surface of the sound absorbing and insulating structure, thereby suppressing an increase in the size of the sound absorbing and insulating structure, while obtaining a sound absorbing and insulating effect targeting relatively low frequencies.

[0094] (15) In some embodiments, in the sound absorbing and insulating structure described in (14) above, the second hole includes a plurality of passages connected in series; The plurality of passages of the second hole are a third passage portion (for example, the above-mentioned linear passage portions 20Fa and 20Ga) extending from the inner circumferential surface toward the outside in the radial direction of the sound absorbing and insulating structure and shorter than the first passage portion; a fourth passage portion (for example, the above-mentioned arc-shaped passage portions 20Fb and 20Gb) located inside the second passage portion in the radial direction and extending from an outer end portion of the third passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; Includes.

[0095] According to the sound absorbing and insulating structure described in (15) above, even if the thickness from the inner peripheral surface to the outer peripheral surface of the cylindrical sound absorbing and insulating structure is small, the length of the second hole can be easily ensured, and compared to a case where the second hole is composed of only one straight passage portion that does not include a bent portion, it is possible to suppress an increase in the thickness from the inner peripheral surface to the outer peripheral surface of the sound absorbing and insulating structure, thereby suppressing an increase in the size of the sound absorbing and insulating structure, and obtain a sound absorbing and insulating effect targeting relatively low frequencies.

[0096] (16) In some embodiments, in the sound absorbing and insulating structure described in (15) above, The plurality of passages of the first hole are The second passage portion includes a fifth passage portion (for example, the above-mentioned linear passage portion 20Ec) extending inward in the radial direction from an end portion of the second passage portion opposite to the first passage portion.

[0097] According to the sound absorbing and insulating structure described in (16) above, even if the thickness from the inner peripheral surface to the outer peripheral surface of the cylindrical sound absorbing and insulating structure is small, the length of the first hole can be easily ensured, and an increase in the thickness from the inner peripheral surface to the outer peripheral surface of the sound absorbing and insulating structure can be suppressed, thereby suppressing an increase in the size of the sound absorbing and insulating structure, while obtaining a sound absorbing and insulating effect targeting relatively low frequencies.

[0098] (17) In some embodiments, in the sound absorbing and insulating structure described in (16) above, The plurality of passage portions of the first hole include a sixth passage portion (for example, the above-mentioned linear passage portion 20Ed) extending along the circumferential direction from the radially inner end of the fifth passage portion toward the first passage portion.

[0099] According to the sound absorbing and insulating structure described in (17) above, even if the thickness from the inner peripheral surface to the outer peripheral surface of the cylindrical sound absorbing and insulating structure is small, the length of the first hole can be easily ensured, and an increase in the thickness from the inner peripheral surface to the outer peripheral surface of the sound absorbing and insulating structure can be suppressed, thereby suppressing an increase in the size of the sound absorbing and insulating structure, while obtaining a sound absorbing and insulating effect targeting relatively small frequencies.

[0100] (18) In some embodiments, in the sound absorbing and insulating structure according to any one of (13) to (17), The nozzle further includes a third hole (for example, a hole among the above-mentioned holes 20E, 20F, 20G excluding the first hole and the second hole) that opens to the inner peripheral surface and does not open to the outer peripheral surface and that has a shape and length different from each of the first hole and the second hole.

[0101] According to the sound absorbing and insulating structure described in (18) above, in the sound absorbing and insulating structures described in (13) to (17) above, the target frequencies at which the sound absorbing and insulating effect can be obtained can be further increased.

[0102] (19) In some embodiments, in the sound absorbing and insulating structure described above in (18), the first hole includes a plurality of passages connected in series; The plurality of passages of the first hole are a first linear passage portion (for example, the linear passage portion 20Ea described above) extending linearly from the inner circumferential surface toward the outside in the radial direction of the sound absorbing and insulating structure; a first arc-shaped passage portion (for example, the above-mentioned arc-shaped passage portion 20Eb) extending from the radially outer end portion of the first linear passage portion along the circumferential direction of the sound absorbing and insulating structure; Including, the second hole includes a plurality of passages connected in series; The plurality of passages of the second hole are a second linear passage portion (for example, the linear passage portion 20Fa) extending from the inner peripheral surface toward an outer side in the radial direction of the sound absorbing and insulating structure and shorter than the first linear passage portion; a second arc-shaped passage portion (for example, the above-mentioned arc-shaped passage portion 20Fb) located inside the first arc-shaped passage portion in the radial direction and extending from an outer end portion of the second linear passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; Including, the third hole includes a plurality of passage portions connected in series, The plurality of passages of the third hole are a third linear passage portion (for example, the linear passage portion 20Ga described above) extending from the inner peripheral surface toward an outer side in the radial direction of the sound absorbing and insulating structure and shorter than the second linear passage portion; a third arc-shaped passage portion (for example, the above-mentioned arc-shaped passage portion 20Gb) that is located inside the second arc-shaped passage portion in the radial direction and extends from an outer end portion of the third linear passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; Includes.

[0103] According to the sound absorbing and insulating structure described in (19) above, in a cylindrical sound absorbing and insulating structure, the first hole, the second hole, and the third hole, which are different in length and shape, can be efficiently arranged in the same plane perpendicular to the axial direction, and a high sound absorbing and insulating effect can be obtained while suppressing an increase in the size of the sound absorbing and insulating structure.

[0104] (20) In some embodiments, in the sound absorbing and insulating structure described above in (19), A cavity (for example, cavities 34 and 36 described above) is formed between the second hole and the third hole.

[0105] According to the sound absorbing and insulating structure described in (20) above, a cavity can be provided in the dead space that does not directly contribute to the sound absorbing and insulating effect in the configuration described in (19) above, thereby making it possible to reduce the weight of the sound absorbing and insulating structure. [Explanation of symbols]

[0106] 2A,2B Sound absorbing and insulating structure 4,22 Sound absorption and insulation structure unit 6 Front page 6a First side 8 Side 2 8a Second side 9, 9I, 9J, 9N holes 9I2,9J2,9N2 Closed end 9I1,9J1,9N1 Open end 9Ia,9Ja,9Jb,9Jc,9Na,9Nb,9Nc,9Nd,9Ne Straight passage section 9Jab, 9Jbc, 9Nab, 9Nbc, 9Ncd, 9Nde Bent section 12 Outer peripheral surface 12a Outer peripheral face 14 Inner peripheral surface 14a Inner peripheral face 16 One end face 18 Other end face 20, 20E, 20F, 20G Holes 20E2, 20F2, 20G2 Closed ends 20E1, 20F1, 20G1 Open ends 20Ea, 20Eb, 20Ec, 20Ed, 20Fa, 20Ga Linear passage portions 20Eb, 20Ed, 20Fb, 20Gb, 20Gd Arc-shaped passage portions 20Eab, 20Ebc, 20Ecd, 20Fab, 20Gab Bend portions 24 Sound absorption and shielding structure layer 30, 32, 34, 36 Cavities

Claims

1. A sound absorbing and insulating structure configured to absorb and insulate noise from a rotating body, The first page and a second surface located opposite the first surface; a first hole that opens to the first surface and does not open to the second surface; a second hole that opens to the first surface and does not open to the second surface, the second hole having a different shape and length from the first hole; Equipped with The sound absorbing and insulating structure is formed in a cylindrical shape, the first surface is an inner peripheral surface of the sound absorbing and insulating structure, and the second surface is an outer peripheral surface of the sound absorbing and insulating structure. the first hole includes a plurality of passage portions connected in series; The plurality of passages include: a first passage portion extending from the inner circumferential surface toward an outer side in a radial direction of the sound absorbing and insulating structure; a second passage portion extending from an outer end portion of the first passage portion in the radial direction along a circumferential direction of the sound absorbing and insulating structure; Including, the second hole includes a plurality of passage portions connected in series; The plurality of passages of the second hole are a third passage portion extending from the inner circumferential surface toward an outer side in a radial direction of the sound absorbing and insulating structure and shorter than the first passage portion; a fourth passage portion located inside the second passage portion in the radial direction and extending from an outer end of the third passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; Including, a third hole that is open to the inner circumferential surface and not open to the outer circumferential surface, the third hole having a shape and a length different from those of the first hole and the second hole; The length of the first hole is 1.8 to 2.2 times the length of the second hole, and the length of the second hole is 1.8 to 2.2 times the length of the third hole. Sound absorbing and insulating structure.

2. 2. The sound absorbing and insulating structure according to claim 1, wherein the first hole, the second hole, and the third hole extend along the same plane perpendicular to the axial direction of the cylindrical sound absorbing structure.

3. The plurality of passages of the first hole are 2. The sound absorbing and insulating structure according to claim 1, further comprising a fifth passage portion extending inward in the radial direction from an end of the second passage portion opposite to the first passage portion.

4. 4. The sound absorbing and insulating structure according to claim 3, wherein the plurality of passage portions of the first hole include a sixth passage portion extending along the circumferential direction from an inner end of the fifth passage portion in the radial direction toward the first passage portion.

5. the first hole includes a plurality of passage portions connected in series; The plurality of passages of the first hole are a first linear passage portion extending linearly from the inner circumferential surface toward an outer side in a radial direction of the sound absorbing and insulating structure; a first arc-shaped passage portion extending from an outer end portion of the first linear passage portion in the radial direction along a circumferential direction of the sound absorbing and insulating structure; Including, the second hole includes a plurality of passage portions connected in series; The plurality of passages of the second hole are a second linear passage portion extending from the inner circumferential surface toward an outer side in a radial direction of the sound absorbing and insulating structure and shorter than the first linear passage portion; a second arc-shaped passage portion located inside the first arc-shaped passage portion in the radial direction and extending from an outer end portion of the second linear passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; Including, the third hole includes a plurality of passage portions connected in series, The plurality of passages of the third hole are a third linear passage portion extending from the inner circumferential surface toward an outer side in a radial direction of the sound absorbing and insulating structure and shorter than the second linear passage portion; a third arc-shaped passage portion located inside the second arc-shaped passage portion in the radial direction and extending from an outer end portion of the third linear passage portion in the radial direction along the circumferential direction of the sound absorbing and insulating structure; The sound absorbing and insulating structure according to claim 1 , comprising:

6. The sound absorbing and insulating structure according to claim 5 , further comprising a cavity formed between the closed ends of the second hole and the third hole.

7. A first surface; a second surface located opposite the first surface; a first hole that opens to the first surface and does not open to the second surface; a second hole that opens to the first surface and does not open to the second surface, the second hole having a different shape and length from the first hole; Equipped with the first hole includes a plurality of passage portions connected in series; The plurality of passages include: a first passage portion that opens to the first surface and extends from the first surface toward the second surface along a direction intersecting the first surface; a second passage portion extending from an end of the first passage portion on the second surface side along a direction intersecting with the extending direction of the first passage portion; a third passage portion extending from an end of the second passage portion opposite to the first passage portion toward the first surface side along a direction intersecting the extending direction of the second passage portion; Including, The plurality of passages include: a fourth passage portion extending from an end of the third passage portion on the first surface side along a direction intersecting with a direction in which the third passage portion extends; a fifth passage portion extending from an end of the fourth passage portion opposite to the fourth passage portion toward the second surface side along a direction intersecting the direction in which the fourth passage portion extends; Including, the second hole includes a plurality of passage portions connected in series; The plurality of passages of the second hole are a sixth passage portion that opens to the first surface and extends from the first surface toward the second surface along a direction intersecting the first surface; a seventh passage portion extending from an end of the sixth passage portion on the second surface side along a direction intersecting with an extending direction of the first passage portion; an eighth passage portion extending from an end of the seventh passage portion opposite to the sixth passage portion toward the first surface side along a direction intersecting the extending direction of the sixth passage portion; Including, a cavity is included between the closed end of the eighth passage portion and the first surface; Sound absorbing and insulating structure.

8. A first surface, a second surface located opposite the first surface; a first hole that opens to the first surface and does not open to the second surface; a second hole that opens to the first surface and does not open to the second surface, the second hole having a different shape and length from the first hole; Equipped with a third hole that opens to the first surface and does not open to the second surface, the third hole having a shape and a length different from those of the first hole and the second hole; a cavity between the closed end of the third hole and the second surface; Sound absorbing and insulating structure.

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