Vibration damping structure, and automobile component and automobile using the same

Abstract

To provide means capable of suppressing a vibration damping structure, using the acoustic black hole effect, from decreasing in sound insulation performance.SOLUTION: A vibration damping structure comprises a vibration-damped member capable of flexural vibration, a rib standing in a direction crossing a surface thereof, and an elastic member, wherein the rib has one end located on a vibration-incident side and the other end located in a vibration-propagation direction, and is provided with a wedge-like part where the rib varies in height satisfying an equation (1), and the elastic member is provided at the wedge-like part or in a region of the vibration-damped member opposed to the wedge-like part to include a region corresponding to the other end. Here, h(x)=ε xn+h1 (1) holds for: x representing the distance measured from an arbitrary position on the other end side as an origin to the one end along the rib; h(x) representing the height of the rib at the distance x from the arbitrary position; h1 representing the height of the rib at the arbitrary position; ε representing a positive constant; and n representing a real number equal to or larger than 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vibration damping structure, an automotive part using the same, and an automobile.

Background Art

[0002] Vibration damping structures for suppressing vibration are used, for example, in automobiles and the like. Various configurations have been proposed for vibration damping structures. For example, Patent Document 1 and Non-Patent Document 1 describe vibration damping structures using an acoustic black hole structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the vibration damping structures disclosed in Patent Document 1 and Non-Patent Document 1 described above, the thickness of the plate-like member is changed along a formula in which the acoustic black hole effect is exhibited from one end to the other end, thereby improving the vibration damping performance. That is, in the vibration damping structures disclosed in these documents, the thickness of the plate-like member is not uniform, and there are thin portions and thick portions in the plate-like member.

[0006] On the other hand, in a part where a vibration damping structure is arranged to exhibit vibration damping performance, there are many cases where noise needs to be blocked. When the vibration damping structure as described above is arranged in such a case, there is a problem that sufficient sound insulation performance cannot be obtained because the surface density of the structure is small in the thin part.

[0007] Therefore, an object of the present invention is to provide a means capable of suppressing a decrease in sound insulation performance in a vibration damping structure using an acoustic black hole effect.

Means for Solving the Problems

[0008] The vibration damping structure according to one embodiment of the present invention includes a vibration damping member that can bend and vibrate, a rib erected in a direction intersecting the surface of the vibration damping member, and an elastic member. The rib has one end located on the side where vibration is incident and the other end located in the direction in which the vibration propagates. At least a part from the one end to the other end of the rib is provided with a wedge-shaped portion in which the height of the rib changes to satisfy the following formula (1). The elastic member is provided at a part corresponding to the other end, in the wedge-shaped portion, or at a part facing the wedge-shaped portion of the vibration damping member: h(x)=ε·x n +h1···Formula (1) In formula (1), x represents the distance measured along the rib toward the one end starting from an arbitrary position on the other end side, h(x) represents the height of the rib at the distance x from the arbitrary position, h1 represents the height of the rib at the arbitrary position, ε represents a positive constant, and n represents a real number of 2 or more.

Effects of the Invention

[0009] According to this embodiment, in a vibration damping structure using an acoustic black hole effect, a decrease in sound insulation performance can be suppressed.

Brief Description of the Drawings

[0010]

Figure 1

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Mode for Carrying Out the Invention

[0011] One embodiment of the present invention is a vibration damping structure including a vibration damping member capable of flexural vibration, ribs erected in a direction intersecting the surface of the vibration damping member, and an elastic member, wherein the rib has one end located on the side where vibration is incident and the other end located in the direction in which the vibration propagates, and at least a part from the one end to the other end of the rib is provided with a wedge-shaped portion in which the height of the rib changes to satisfy the following formula (1), and the elastic member is provided in the wedge-shaped portion so as to include a portion corresponding to the other end, or in a portion of the vibration damping member facing the wedge-shaped portion: h(x)=ε·x n +h1 ··· Formula (1) In formula (1), x represents the distance measured along the rib toward the one end starting from an arbitrary position on the other end side, h(x) represents the height of the rib at the distance x from the arbitrary position, h1 represents the height of the rib at the arbitrary position, ε represents a positive constant, and n represents a real number of 2 or more.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited only to the following embodiments. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios. In this specification, "a~b" indicating a range means "a or more and b or less". Also, unless otherwise specified, measurements such as operations and physical properties are performed under the conditions of room temperature (20~25°C) / relative humidity 40~50%.

[0013] [Configuration of Vibration Damping Structure] FIG. 1 is a perspective view schematically showing the configuration of a vibration damping structure according to an embodiment of the present invention, and represents the configuration of a vibration damping structure 10 according to an embodiment of the present invention. FIG. 2 is a side view (YZ plan view seen from the A direction) of the vibration damping structure shown in FIG. 1. FIG. 3 is an explanatory view for explaining the shape of the rib 12a shown in FIG. 1. FIG. 4 is a rear view (XZ plan view seen from the B direction) of the vibration damping structure shown in FIG. 1.

[0014] The vibration damping structure 10 includes a vibration damping member 11 that can bend and vibrate, a pair of ribs 12a and 12b provided at the ends of the vibration damping member 11 so as to face each other and standing in a direction orthogonal to the surface of the vibration damping member 11, an elastic member 13, and a connecting portion 14 that connects the pair of ribs 12a and 12b to each other at a portion separated from the vibration damping member 11. The elastic member 13 is joined to the vibration damping member 11. The vibration damping structure 10 having such a configuration attenuates the vibration of the vibration damping member 11. In the following description, the thickness direction of the plate-like vibration damping member 11 may be referred to as the Z direction, and among the directions intersecting this, the width direction of the vibration damping member 11 may be referred to as the X direction, and the longitudinal direction of the vibration damping member 11 may also be referred to as the Y direction.

[0015] [Vibration Damping Member] The vibration-damping member 11 may be made of a material capable of flexural vibration. However, from the viewpoints that the vibration-damping effect by the vibration-damping structure is more remarkably exhibited due to the small vibration-damping action (damping coefficient) and it is easy to handle, it is preferably made of a metal material such as iron and steel. The vibration-damping member 11 is a plate-like member having a predetermined width, length, and thickness. The width of the vibration-damping member is, for example, 30 mm to 1000 mm. The length of the vibration-damping member is larger than the width and is, for example, 50 mm to 3000 mm. Here, for example, as shown in FIG. 2, one of the ends of the vibration-damping member 11 in the Y direction is joined to the elastic member 13.

[0016] (Rib) The ribs 12a and 12b are arranged so as to stand in a direction intersecting the surface (XY plane) of the vibration-damping member 11.

[0017] There is no particular limitation on the constituent material of the rib, but the rib is preferably also composed of a material that can bend and vibrate. Since the vibration damping effect (damping coefficient) is small, the vibration damping effect of the vibration damping structure is more significantly manifested. From the viewpoint of ease of handling, it is preferably composed of a metal material such as iron and steel. Regarding the arrangement form of the rib, there is no particular limitation as long as it stands in a direction intersecting the surface of the member to be vibration-damped. For example, in the illustrated embodiment, the rib is provided parallel to the longitudinal direction of the member to be vibration-damped 11, but it may be provided at a certain angle with respect to the longitudinal direction of the member to be vibration-damped 11. Also, in the illustrated embodiment, the rib is provided in a direction perpendicular to the surface of the member to be vibration-damped 11, but it may be provided at a certain angle with respect to the perpendicular direction. Furthermore, the rib does not necessarily need to be provided in a pair (two sheets), and it is possible to obtain the effects of this embodiment even if only one rib or three or more ribs are provided. However, the rib is preferably provided in a direction substantially perpendicular to the surface of the member to be vibration-damped. More preferably, a pair of ribs are provided in a direction substantially perpendicular to the surface of the member to be vibration-damped. Furthermore, it is preferably provided so as to face each other at the ends in the width direction (X direction) of the member to be vibration-damped. According to these configurations, the vibration damping structure 10 can be formed in a groove shape, and the variations in the use of members when arranging it are expanded, and there is an advantage that excellent vibration damping performance can be exhibited even when used for structural parts such as frames (ladder frames, seat frames, etc.).

[0018] Referring to FIG. 3, the shape of the rib 12a will be described. The rib 12a is a plate-like member having a predetermined width w (the size in the X direction; refer to FIG. 4), length l (the size in the Y direction), and height h (the size in the Z direction). The size of the width w is, for example, 0.5 mm to 50 mm, preferably 20 mm or less, and more preferably 10 mm or less. The size of the length l is usually not more than the length of the member to be vibration-damped, and is, for example, 30 mm to 3000 mm. The rib 12a has one end e1 and the other end e2 in the direction of the length l. The rib 12a, for example, has the same width w from one end e1 to the other end e2, but the size of the width w may change between one end e1 and the other end e2.

[0019] A thick portion 12C is provided on one end e1 side of the rib 12a, and a wedge-shaped portion 12W is provided on the other end e2 side. The thick portion 12C has a constant height hc. The size of the constant height hc is larger than the size of the width w, for example, 3 to 100 mm. In order to suppress the size of the vibration damping structure 10 in the Z direction, it is preferably 30 mm or less, and more preferably 20 mm or less. When the vibration damping structure 10 is in use, vibration is incident from one end e1 side of the rib 12a and propagates toward the other end e2 side.

[0020] As described above, in the illustrated embodiment, a wedge-shaped portion 12W is provided on the other end e2 side of the rib 12a. The wedge-shaped portion 12W is provided adjacent to the thick portion 12C, for example, and is provided from a position eW between one end e1 and the other end e2 to the other end e2. In this wedge-shaped portion 12W, the height h gradually decreases from the position eW toward the other end e2. That is, the size of the height h of the wedge-shaped portion 12W is the largest at the position eW and the smallest at the other end e2. The height h of this wedge-shaped portion 12W satisfies the following formula (1): h(x)=ε·x n +h1 ··· Formula (1) In Formula (1), x represents the distance measured along the rib 12a toward the one end e1 starting from an arbitrary position on the other end e2 side, h(x) represents the height of the rib at the distance x from the arbitrary position, h1 represents the height of the rib at the arbitrary position, ε represents a positive constant, and n represents a real number of 2 or more.

[0021] The arbitrary position on the other end e2 side, which is the measurement starting point of the distance x in the above formula (1), is an arbitrary position closer to the other end e2 than the one end e1, for example, the other end e2. The distance x is measured, for example, along the center (i.e., the center line) in the width w direction of the rib 12a. Further, h1 corresponds to the height of the rib 12a at the measurement starting point of the distance x (for example, the other end e2). The value of h1 may be 0 or more, but it is preferably greater than 0. If h1>0, the second moment of area, which is an index of the resistance to the force bending the vibration damping structure 10, becomes large, and there is an advantage that vibrations at frequencies lower than the frequency at which the acoustic black hole effect is exhibited due to the high rigidity of the vibration damping structure 10 can be reduced. However, if h1 is too large, the acoustic black hole effect due to providing the wedge-shaped portion of the rib decreases, so h1 is preferably 1 mm or less, and more preferably 0.5 mm or less.

[0022] By providing such a wedge-shaped portion 12W on the other end e2 side of the vibration-damping member 11, a so-called acoustic black hole structure is realized. Thereby, the reflection of the vibration wave at the other end e2 of the vibration-damping member 11 is suppressed, and the vibration incident from the one end e1 side toward the other end e2 side can be effectively attenuated. In the wedge-shaped portion 12W, at least a part thereof is preferably provided at a position closer to the other end e2 than the one end e1, in other words, at a position closer to the other end e2 than the center between the one end e1 and the other end e2.

[0023] Regarding the frequency at which vibration attenuation is possible by the wedge-shaped portion 12W, by increasing the length L of the wedge-shaped portion 12W, vibrations at lower frequencies can be effectively attenuated. The length L of the wedge-shaped portion 12W is measured, for example, along the center (i.e., the center line) in the width w direction of the rib 12a starting from the other end e2. The length L of the wedge-shaped portion 12W is preferably 70% or more of the length l of the vibration-damping member 11, and more preferably 75% or more. By increasing the ratio of the wedge-shaped portion 12W in the vibration-damping member 11, vibration can be more effectively attenuated. Although illustration is omitted, for example, the rib 12b also has the same configuration as the above rib 12a.

[0024] (Elastic member) The elastic member 13 joined to the other end e2 of the vibration-damping member 11 plays a role of converting the vibration energy collected at the other end e2 into heat energy and attenuating it by means of an acoustic black hole structure. The elastic member 13 is composed of, for example, a plate-shaped viscoelastic material. It is preferable that the thickness of this plate-shaped elastic member 13 is larger than the thickness of the vibration-damping member 11 at the position corresponding to the other end e2 of the rib. The viscoelastic material constituting the elastic member 13 is preferably a polymer material such as rubber. The specific gravity of the elastic member 13 is preferably about the same as that of the vibration-damping member 11 or larger than that of the vibration-damping member 11. With such an elastic member 13, the vibration energy collected at the other end e2 can be efficiently attenuated.

[0025] In the illustrated embodiment, the elastic member 13 is provided at a portion of the vibration-damping member 11 facing the wedge-shaped portion 12W so as to include a portion corresponding to the other end e2 of the rib 12a (a portion overlapping the other end e2 when the vibration-damping structure is viewed in the XY plane) (FIG. 2). In this case, an intermediate layer such as an adhesive layer having a certain thickness may be interposed between the vibration-damping member 11 and the elastic member 13. Further, as shown in FIGS. 5 and 6, the elastic member 13 may be provided directly on the wedge-shaped portion 12W of the vibration-damping member 11 or via the above intermediate layer as necessary. With any of these arrangement forms, the elastic member 13 can exhibit its function and can sufficiently attenuate the vibration energy transmitted while attenuating the wedge-shaped portion 12W of the rib.

[0026] (Connecting portion) In the form where a pair of ribs is provided as in the present embodiment and these pair of ribs are provided so as to face each other at the end portion of the vibration-damping member, the pair of ribs are connected to each other at a portion separated from the vibration-damping member. The connecting portion is also preferably composed of a material that can bend and vibrate, and from the viewpoint of ease of handling, etc., it is preferably composed of a metal material such as iron and steel. Regarding the arrangement form of the ribs, there is no particular limitation as long as the pair of ribs can be connected to each other at a portion separated from the vibration-damping member. For example, in the illustrated embodiment, the connecting portion is provided so as to connect the thick portions of the pair of ribs. However, it is not limited to such a mode only, and instead of or in addition to the above mode, it may be provided so as to connect only the wedge-shaped portions to each other. According to these configurations, the vibration-damping structure can be formed in a cylindrical shape, and the variations in member uses when arranging this are expanded, and there is an advantage that excellent vibration-damping performance can be exhibited even when used for structural parts such as frames (ladder frames, seat frames, etc.).

[0027] [Effects of the vibration-damping structure] In the vibration-damping structure 10 according to the present embodiment, the wedge-shaped portions 12W provided at a part of the ribs 12a and 12b function as an acoustic black hole structure. As a result, the vibration of the vibration-damping member 11 can be effectively attenuated. Also, different from the conventional vibration-damping structure, the thickness of the vibration-damping member 11 is maintained uniformly from one end e1 side to the other end e2 side of the ribs 12a and 12b. As a result, a decrease in the areal density over the entire vibration-damping member 11 is prevented as compared with the case where the thickness of the vibration-damping member 11 is changed to provide a thin portion. As a result, a decrease in the sound insulation performance due to the vibration-damping member 11 caused by changing the plate thickness of the vibration-damping member 11 is also prevented, and a vibration-damping structure excellent in sound insulation performance can be realized.

[0028] [Application examples] The vibration damping structure 10 described in the above embodiment can be suitably used for applications that attenuate various vibrations. Among them, the vibration damping structure 10 is preferably used when mounted on a vehicle. It can be applied to any of the interior parts in the vehicle compartment and the exterior parts outside the vehicle compartment. As an example of the application site, dash insulators, dash panels, floor panels, floor carpets, spacers, door panels, door trims of doors, sound absorption structures inside door trims, sound absorption structures inside compartments, instrument panels, instrument center boxes, instrument upper boxes, air conditioner housings, roof panels, roof trims, sound absorption structures inside roof trims, sun visors, rear seat air conditioner ducts, cooling ducts of battery cooling systems in battery-powered vehicles, cooling fans, trims of center consoles, sound absorption structures inside consoles, parcel trims, parcel panels, headrests of seats, seat backs of front seats, seat backs of rear seats, engine, housings of power trains such as motors, etc. are applicable. Further, in the trunk, it is applicable to trims of trunk floors, trunk boards, trims of trunk sides, sound absorption structures inside trims, drafter covers, etc. It can also be applied inside the vehicle skeleton and between panels, for example, it is applicable to pillar trims and fenders. Among them, since it is excellent in vibration damping, lightweight, and also excellent in sound insulation performance, it is preferably used for automotive parts.

[0029] As described above, the vibration damping structure according to one aspect of the present invention has been described using the embodiment. However, the present invention can be appropriately added to, modified, and omitted by those skilled in the art within the scope of its technical idea. For example, the configurations, shapes, sizes, etc. of each part of the vibration damping structure described in the above embodiment and examples are examples, and other configurations, shapes, sizes, etc. may also be used.

[0030] For example, in the above embodiment, an example in which the wedge-shaped portion 12W is provided from the position eW to the other end e2 has been described. However, the wedge-shaped portion 12W may be provided at least in part from one end to the other end of the rib. That is, the wedge-shaped portion 12W does not have to include the other end e2. For example, in a part on the other end e2 side, the thickness thereof may be constant. Further, as shown in FIG. 7, a plurality of wedge-shaped portions 12W1 and 12W2 may be provided on one rib.

[0031] Furthermore, in the above embodiment, an example in which the vibration control structure is attached to the plate-shaped vibration control member has been described. However, the shape of the vibration control member may be other shapes such as a rod shape. Also, in the above embodiment, an example in which the plate thickness of the vibration control member is uniform over the entire surface has been described. However, as long as it does not adversely affect the operation and effects of the present invention, the plate thickness of at least a part of the vibration control member may be different from that of other parts.

[0032] Note that the following embodiments are also included in the scope of the present invention: the vibration control structure according to claim 1 having the features of claim 2; the vibration control structure according to claim 1 or 2 having the features of claim 3; the vibration control structure according to claim 3 having the features of claim 4; the vibration control structure according to claim 4 having the features of claim 5; the vibration control structure according to any one of claims 1 to 5 having the features of claim 6; an automotive part having the vibration control structure according to any one of claims 1 to 6; an automobile having the vibration control structure according to any one of claims 1 to 6 or the automotive part according to claim 7.

Example

[0033] Hereinafter, the present invention will be described in more detail by way of examples. However, the technical scope of the present invention is not limited only to the following examples.

[0034] [Example 1] (Production of vibration control structure) As a raw material for the vibration-damping member and ribs that make up the vibration-damping structure, a steel square pipe (model number: TK132-14; outer dimensions: width 32 mm, length 2000 mm, height 14 mm; plate thickness 1.2 mm) made by Hikari was prepared. Next, this steel square pipe was machined to produce a structure in which the vibration-damping member 11 and a pair of ribs 12a, 12b shown in Fig. 1 were integrally formed (size of the vibration-damping member: thickness 1.2 mm, width 32 mm, length 200 mm; size of the rib: width w 1.2 mm, length l 200 mm, height of the thick part hc 12.8 mm, length of the wedge-shaped part L 150 mm). Here, the minimum height h1 of the wedge-shaped part is 0.5 mm, and the wedge-shaped part was produced so that the height h of the wedge-shaped part of the rib changes satisfying the following formula (2) (in formula (1), h1 = 0.5, ε = 12.3 / 150 2 , n = 2 was set.).

[0035] h(x)=(12.3 / 150 2 )x 2 +0.5 ··· Formula (2) Subsequently, as a raw material for the elastic member that makes up the vibration-damping structure, a natural rubber sheet (model number: BNSEA2-5, thickness 2 mm, Shore A hardness 65) made by Misumi was prepared. Next, this sheet was cut into a size of 20 mm × 29.6 mm and attached to the surface of the structure produced above, which is opposite to the surface where the ribs of the vibration-damping member are formed, so that the longitudinal direction of the sheet is along the width direction of the vibration-damping member. In this way, the vibration-damping structure of this embodiment having the configuration shown in Fig. 1 except for having no connecting part was produced.

[0036] (Evaluation of the vibration characteristics of the vibration-damping structure) First, the vibration-damping structure produced above was placed on two rectangular sponges as shown in Fig. 8 and freely supported. Next, the transfer function (frequency response function (FRF)) was calculated using the method shown below.

[0037] Specifically, the transfer function (frequency response function (FRF)) was measured using the measurement system 200 shown in FIG. 9. The measurement system 200 includes an impulse hammer 210 (manufactured by PCB Piezotronics, Inc., model 086C03, hard tip), an acceleration sensor 220 (manufactured by PCB Piezotronics, Inc., model 356A01), an FFT (Fast Fourier Transform) analyzer 230 (manufactured by Siemens AG, SCADADSIII), and a PC (Personal Computer) 240. The impulse hammer 210 and the acceleration sensor 220 are connected to the FFT analyzer 230, and the FFT analyzer 230 is communicably connected to the PC 240.

[0038] Here, the acceleration sensor 220 was attached to a position (response point (● shown in FIG. 8)) on one end side of the surface on the side where the ribs 12a and 12b of the vibration-damping member 11 shown in FIG. 8 are formed, and a position near the response point (●) (excitation point (× shown in FIG. 8)) was struck with the impulse hammer 210. At this time, the acceleration [m / s 2 measured by the acceleration sensor 220 and the value of the impact force [N] of the impulse hammer were input to the FFT analyzer 230 to calculate the transfer function (frequency response function (FRF)) [m / s 2 / N]. At this time, the measurement frequency range was set to 0 Hz to 10240 Hz, and Δf = 2.5 Hz.

[0039] (Evaluation of Vibration Characteristics by CAE Analysis) On the one hand, a 3D model of the vibration damping structure fabricated in Example 1 above was created, and its vibration characteristics were evaluated by CAE (Computer-Aided Engineering) analysis. Specifically, finite element (FE) analysis was performed using analysis software NX-Nastran (manufactured by Siemens AG). At this time, the boundary condition of the sample was set to free, and the sample was meshed with tetrahedral elements. Also, point excitation was applied to the same excitation points as above, and the acceleration response was acquired at the same response points as above to calculate the transfer function (frequency response function (FRF)). In creating the 3D model of the vibration damping structure, the physical property parameters of steel and the elastic member (natural rubber), which are the constituent materials of the vibration damping structure, were adopted as the values shown in Table 1 below.

[0040]

Table 1

[0041] As a result of the CAE analysis using the 3D model implemented in this way, a transfer function (frequency response function (FRF)) almost equivalent to the above-described experiment was calculated. From this, it was shown that the CEA analysis using the physical property parameters shown in Table 1 above is effective for predicting the transfer function (frequency response function (FRF)) of the vibration damping structure according to one form of the present invention.

[0042] [Example 2] A vibration damping structure having the following structure was 3D modeled using the same method as above, and its transfer function (frequency response function (FRF)) was calculated using the same method (CAE analysis) as above. The results are shown in FIG. 10.

[0043] In this embodiment, the vibration damping structure modeled in 3D has a rib (size: thickness 1.2 mm, width 32 mm, length 200 mm; rib size: width w 1.2 mm, length l 200 mm, height hc of the thick part 12.8 mm, length L of the wedge-shaped part 50 mm, minimum height h1 of the wedge-shaped part is 0.5 mm) having the same material and size as each of the pair of ribs in Embodiment 1 described above. The height h of the wedge-shaped part of this rib changes satisfying the following formula (3) (in formula (1), h1 = 0.5, ε = 12.3 / 150 2 , and n = 2.).

[0044] h(x)=(12.3 / 150 2 )x 2 +0.5 ··· Formula (3) The above rib is arranged at the center of one surface of a steel plate (size: width 100 mm, length 300 mm, thickness 1.2 mm). Further, an elastic member (size: width 100 mm (X direction), length 30 mm (Y direction), thickness (Z direction) 2 mm) made of the same natural rubber sheet as in Embodiment 1 described above is attached to the other surface of the steel plate such that the longitudinal direction of the sheet is along the width direction of the vibration-damping member and the end on the other end side of the sheet coincides with the end on the other end side of the rib when the vibration-damping structure is viewed in plan.

[0045] Here, as Comparative Example 1 as a control, a vibration-damping structure obtained by 3D modeling the same vibration-damping structure as in Embodiment 2 described above was used, except that the height h of the rib was constant at 12.8 mm along the Y direction and no elastic member was arranged.

[0046] From the results shown in FIG. 10, it can be said that it was confirmed that the vibration-damping structure according to the present invention is superior in vibration damping performance as compared with a vibration-damping structure having no wedge-shaped part on the rib and no elastic member. Also, it can be seen that even when only one rib is provided instead of a pair of ribs, the effects of the present invention can be sufficiently exhibited.

[0047] [Embodiment 3] A vibration control structure with the sizes of the vibration-isolated member and ribs changed with respect to Example 1 was 3D modeled using the same method as above, and its transfer function (frequency response function (FRF)) was calculated using the same method (CAE analysis) as above. The results are shown in FIG. 11.

[0048] In the vibration control structure 3D modeled in this example, the size of the vibration-isolated member was set to a thickness of 1.2 mm, a width of 32 mm, and a length of 200 mm. Also, the sizes of the pair of ribs were set the same as those of the ribs in Example 2 described above. For this reason, the wedge-shaped portion of the rib in this example satisfies the above formula (3).

[0049] Here, as Comparative Example 2 which is a control, a 3D model of the same vibration control structure as that of Example 3 described above was used, except that the height h of the rib was constant at 12.8 mm along the Y direction and no elastic member was arranged.

[0050] It can also be said that it was confirmed from the results shown in FIG. 11 that the vibration control structure according to the present invention is superior in vibration control performance as compared with a vibration control structure having no wedge-shaped portion on the rib and no elastic member. Also, according to the results shown in FIG. 11, it can be seen that the vibration control structure of Example 3 exhibits a particularly excellent vibration control effect against vibrations having frequencies of 4000 Hz or higher.

[0051] [Example 4] A vibration control structure with the sizes of the vibration-isolated member and ribs further changed with respect to Example 3 was 3D modeled using the same method as above, and its transfer function (frequency response function (FRF)) was calculated using the same method (CAE analysis) as above. The results are shown in FIG. 12.

[0052] In the vibration control structure 3D modeled in this embodiment, the size of the vibration control member was 1.2 mm in thickness, 32 mm in width, and 350 mm in length. Also, the size of a pair of ribs was 1.2 mm in width w, 350 mm in length l, 12.8 mm in height hc of the thick portion, 300 mm in length L of the wedge-shaped portion, and 0.5 mm in minimum height h1 of the wedge-shaped portion. The height h of the wedge-shaped portion of this rib changes while satisfying the following formula (4) (in formula (1), h1 = 0.5, ε = 12.3 / 300 2 , and n = 2.).

[0053] h(x)=(12.3 / 300 2 )x 2 +0.5 ··· Formula (4) Here, as Comparative Example 3 as a control, a 3D model of the same vibration control structure as in Example 4 described above was used, except that the height h of the rib was constant at 12.8 mm along the Y direction and no elastic member was arranged.

[0054] From the results shown in FIG. 12 as well, it can be said that it was confirmed that the vibration control structure according to the present invention is superior in vibration control performance as compared with a vibration control structure having no wedge-shaped portion on the rib and no elastic member. Also, according to the results shown in FIG. 12, in the vibration control structure of Example 4, the length l of the wedge-shaped portion of the rib is twice that of Example 3 as compared with Example 3. As a result, in Example 4, it can be seen that the lower limit value of the frequency at which the vibration control effect is exhibited is 800 Hz or more, which is about 1 / 4, in a form inversely proportional to the square of this length l.

[0055] [Example 5] The vibration control structure 3D modeled in Example 3 described above was actually manufactured using the same raw materials as those used in Example 1. Also, as Comparative Example 4 as a control, the same vibration control structure as in Example 5 was actually manufactured, except that the height h of the rib was constant at 12.8 mm along the Y direction and no elastic member was arranged.

[0056] For the vibration damping structures of Example 5 and Comparative Example 4 fabricated in this way, the transfer function (frequency response function (FRF)) [m / s 2 / N] was calculated using the same method as in Example 1 described above. The results are shown in Fig. 13.

[0057] As shown in Fig. 13, also for the results of actually measuring the transfer function (frequency response function (FRF)), the peak of the graph of Example 5 is smaller than the peak of the graph of the corresponding Comparative Example 4. Also, it can be seen that the vibration damping structure of Example 5 exhibits an excellent vibration damping effect particularly for vibrations having a frequency of 4000 Hz or more. Here, when comparing the results of Fig. 11 showing the results of simulations using 3D models of these vibration damping structures with Fig. 13, the peaks of the graphs of the examples are all smaller in the frequency range of 4000 Hz or more, and from this, the effectiveness of the 3D model was also confirmed.

[0058] [Reference Example 1] An acoustic black hole structure was provided at six locations on one surface of a steel plate (width 460 mm, length 520 mm, thickness 1.6 mm), and an elastic member with a diameter of 40 mm was arranged at the center of each acoustic black hole structure to fabricate a sound insulation material sample (Fig. 14(a)). Note that the same elastic member as above was cut and used. Also, the cross-section of this acoustic black hole structure is shown in Fig. 14(b). As shown in Fig. 14(b), the cross-section of the acoustic black hole structure has a structure in which a pair of wedge-shaped portions face each other. Therefore, the height h of the wedge-shaped portion of the cross-section of this acoustic black hole structure changes satisfying the following formula (5) (in formula (1), h1 = 0.2, ε = 1.4 / 50 2 , n = 2).

[0059] h(x)=(1.4 / 50 2 )x 2 +0.2 ··· Formula (5) Next, the sound insulation material sample prepared above was installed at the opening of the sound insulation box, and the sound pressure difference between the sound pressure of the speaker installed inside the sound insulation box and the sound pressure measured by the microphone installed at a position 500 mm above the sound insulation material sample was measured, and the insertion loss for sound waves of each frequency was calculated from the obtained measurement values. The dimensions of the opening of the sound insulation box are shown in Fig. 14(c). Also, when installing the sound insulation material sample at the opening of the sound insulation box, it was installed so that none of the acoustic black hole structures overlapped with the opening.

[0060] Here, as Comparative Reference Example 1 as a control, a steel plate without an acoustic black hole structure was used as the sound insulation material sample as it was, and the insertion loss was calculated by the same method. The results are shown in Fig. 15.

[0061] Considering with reference to Fig. 15, Reference Example 1 corresponds to the configuration of the prior art in which the plate thickness of the vibration-damping member is changed according to the formula of the acoustic black hole structure. On the other hand, Comparative Reference Example 1 corresponds to the configuration of a vibration-damping structure body in which the plate thickness of the vibration-damping member is not changed. As a result of comparing these sound insulation performances, it can be seen that Comparative Reference Example 1 exhibits better sound insulation performance due to its larger surface density than Reference Example 1. And since the vibration-damping structure body according to the present invention is further provided with ribs with respect to the configuration of Comparative Reference Example 1, it is expected that its surface density will be even larger than that of the sample of Comparative Reference Example 1. Therefore, it is clear that the graph of the insertion loss of the vibration-damping structure body according to the present invention will shift further upward than that of Comparative Reference Example 1 shown in Fig. 15 (which exhibits better sound insulation performance than Reference Example 1 corresponding to the prior art) and exhibit better sound insulation performance. From these facts, it can be said that the vibration-damping structure body according to the present invention exhibits excellent vibration-damping effects while suppressing a decrease in sound insulation performance.

Explanation of Signs

[0062] 10 Vibration-damping structure body 11 Vibration-damping member 12a, 12b Ribs 12C Thick part 12W Wedge-shaped part 13 Elastic member 14 Connection part e1 One end e2 The other end eW Position 200 Measurement system for transfer function (frequency response function (FRF)) 210 Impact hammer 220 Acceleration sensor 230 FFT analyzer 230 240 PC x Distance h, hc Height l, L Length

Claims

1. A vibration-damping structure comprising a vibration-damping member capable of flexural vibration, a rib erected in a direction intersecting the surface of the vibration-damping member, and an elastic member, wherein the rib has one end located on the side where vibration is incident and the other end located in the direction in which the vibration propagates, and a wedge-shaped portion is provided in at least a part from the one end to the other end of the rib, and the height of the rib changes so as to satisfy the following formula (1), and the elastic member is provided in the wedge-shaped portion or at a portion of the vibration-damping member facing the wedge-shaped portion so as to include a portion corresponding to the other end: In formula (1), h(x) = ε・x ｎ + h １ ・・・ Equation (1)

2. x represents the distance measured along the rib from an arbitrary position on the other end side towards the one end, h(x) represents the height of the rib at the distance x from the arbitrary position, and h １ represents the height of the rib at the arbitrary position, ε represents a positive constant, and n represents a real number of 2 or more.

3. h １ The vibration damping structure according to claim 1, wherein h is greater than 0. The vibration-damping structure according to claim 1 or 2, wherein the rib is erected in a direction substantially perpendicular to the surface of the vibration-damping member along an end portion of the vibration-damping member.

4. The vibration-damping structure according to claim 3, wherein a pair of ribs are provided, and the pair of ribs are provided so as to face each other at an end portion of the vibration-damping member.

5. The vibration-damping structure according to claim 4, further comprising a connecting portion for connecting the pair of ribs to each other at a portion separated from the vibration-damping member.

6. The vibration-damping structure according to claim 1 or 2, wherein the vibration-damping member and the rib are made of a metal material.

7. An automotive part having the vibration-damping structure according to claim 1 or 2.

8. An automobile having the vibration-damping structure according to claim 1 or 2, or the automotive part according to claim 7. ​ ​

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