Resonant absorber, tire, and method for attaching resonant absorber

Abstract

The resonance sound absorber attached to the inner cavity of the tire includes a resonance box having a self-supporting outer wall, a hollow portion formed inside the outer wall, and an opening that opens the hollow portion to the outside of the outer wall. The outer wall includes a bottom wall portion attached to the inner cavity and a top wall portion that forms a hollow portion between the bottom wall portion. The top wall portion is curved in a convex shape. The tire includes the above-described resonance sound absorber attached to the inner cavity. The method for attaching the resonance sound absorber to the inner cavity of the tire includes a pretreatment step of polishing an attachment region to which the resonance sound absorber in the inner cavity is to be attached, and an attachment step of attaching the resonance sound absorber to the attachment region after the pretreatment step.

Description

Technical Field

[0001] The present disclosure relates to a resonance absorber, a tire, and a method for attaching the resonance absorber.

Background Art

[0002] Conventionally, a resonance absorber that reduces tire cavity resonance noise generated during vehicle travel by Helmholtz resonance is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A conventional resonance absorber is configured with an opening formed in an outer wall that forms a hollow portion. This outer wall is formed in a substantially cubic shape and includes a bottom wall portion attached to the inner cavity portion of the tire, a top wall portion with an opening formed facing the inner cavity portion of the tire, and side wall portions connected to the bottom wall portion and the top wall portion. Further, this outer wall has self-supporting properties that allow it to stand on its own without being filled with a filler such as a porous sound absorber in the hollow portion. And since the tire cavity resonance noise generated during vehicle travel is in a low frequency band of, for example, about 200 Hz to 300 Hz, in a conventional resonance absorber, the length of the opening, the volume of the hollow portion, etc. are adjusted so as to reduce the tire cavity resonance noise generated during vehicle travel.

[0005] Incidentally, when the inventors of the present application performed a simulation of a vehicle traveling at high speed with a resonance sound absorber attached to the inner cavity of a tire, it was found that even a resonance sound absorber having sufficient self-supporting properties in a stationary state would greatly deform around the top wall portion due to the generation of a large centrifugal force in the resonance sound absorber. When the resonance sound absorber is deformed by such a centrifugal force, the sound absorption frequency characteristics of the resonance sound absorber shift to the high-frequency side, and there is a possibility that the resonance sound in the tire inner cavity cannot be appropriately reduced.

[0006] Note that it is possible to suppress the deformation of the resonance sound absorber due to centrifugal force by filling the hollow portion with a filler such as a porous sound absorber. However, when attached to a tire that is strongly required to be lightweight, filling the hollow portion with a filler such as a porous sound absorber is not necessarily the optimal solution. Therefore, an improvement that can suppress the deformation of the resonance sound absorber due to centrifugal force is desired even when the hollow portion is not filled with a filler such as a porous sound absorber.

[0007] An object of the present disclosure is to provide a resonance sound absorber capable of suppressing deformation of the resonance sound absorber due to centrifugal force, a tire to which this resonance sound absorber is attached, and a method for attaching this resonance sound absorber.

Means for Solving the Problems

[0008] The resonance sound absorber according to the present disclosure is a resonance sound absorber attached to the inner cavity of a tire, and includes a resonance box having an outer wall with self-supporting properties, a hollow portion formed inside the outer wall, and an opening that opens the hollow portion to the outside of the outer wall. The outer wall includes a bottom wall portion attached to the inner cavity portion and a top wall portion that forms a hollow portion between the bottom wall portion. The top wall portion is curved convexly.

[0009] In this resonance absorber, since it includes a resonance box having a self-supporting outer wall, a hollow portion formed inside the outer wall, and an opening that opens the hollow portion to the outside of the outer wall, the resonance absorber can function as a Helmholtz resonator. Further, since the outer wall of the resonance box has self-supporting properties, it can maintain a self-supporting state without filling the hollow portion with a filler such as a porous sound absorber. Note that the hollow portion may be filled with a filler such as a porous sound absorber. And, since the top wall portion of this self-supporting outer wall is curved convexly, it is easier to receive the force directed toward the bottom wall portion. Thereby, it is possible to suppress the resonance absorber from deforming due to the centrifugal force generated when a vehicle having the resonance absorber attached to the inner cavity portion of the tire travels at high speed.

[0010] In the resonance absorber described above, the top wall portion may be connected to the bottom wall portion. In this resonance absorber, since the top wall portion is connected to the bottom wall portion, the supporting force of the top wall portion by the bottom wall portion becomes higher. Thereby, it is possible to further suppress the deformation of the resonance absorber due to the centrifugal force.

[0011] In the resonance absorber described above, the resonance box may include a hollow neck portion that communicates the opening and the hollow portion. In this resonance absorber, since the resonance box includes a hollow neck portion that communicates the opening and the hollow portion, the resonance frequency of the Helmholtz resonance can be adjusted by adjusting the length of the neck portion. And, by making the neck portion longer, it is possible to generate the Helmholtz resonance of the resonance frequency in the low frequency range, so that it is possible to reduce the resonance sound in the low frequency range such as the resonance sound of the tire inner cavity.

[0012] In the resonance absorber described above, at least a part of the neck portion may be disposed inside the outer wall. In this resonance absorber, since at least a part of the neck portion is disposed inside the outer wall, it is possible to make the resonance absorber smaller while making it possible to generate the Helmholtz resonance of the resonance frequency in the low frequency range by making the neck portion longer.

[0013] In the resonance absorber described above, the neck portion may be disposed on the bottom wall portion so as to extend along the bottom wall portion. In this resonance absorber, since the neck portion is disposed on the bottom wall portion so as to extend along the bottom wall portion, movement of the neck portion due to centrifugal force can be suppressed.

[0014] In the resonance absorber described above, the resonance box may be configured to be long in a first direction, and the opening may be formed at an end portion of the outer wall in the first direction. In this resonance absorber, since the resonance box is configured to be long in the first direction and the opening is formed at an end portion of the outer wall in the first direction, the neck portion can be lengthened while reducing the size of the resonance box.

[0015] In the resonance absorber described above, the top wall portion may be formed in an arc shape in a cross section orthogonal to the first direction. In this resonance absorber, since the top wall portion is formed in an arc shape in a cross section orthogonal to the first direction, deformation of the top wall portion due to centrifugal force can be effectively suppressed.

[0016] In the resonance absorber described above, the outer wall has a side wall portion located at an end portion in the first direction and having an opening formed therein, and the side wall portion may be curved convexly. In this resonance absorber, since the opening is formed in the side wall portion located at the end portion in the first direction, the neck portion can be lengthened while reducing the size of the resonance box. And since the side wall portion is curved convexly, non-uniformity of rigidity in the outer wall can be alleviated. For this reason, deformation of the resonance absorber due to centrifugal force can be further suppressed.

[0017] In the resonance absorber described above, the outer wall has a side wall portion located at an end portion in the first direction and having an opening formed therein, and the side wall portion may be formed in a flat plate shape extending in a direction intersecting the first direction. In this resonance absorber, since the opening is formed in the side wall portion located at the end portion in the first direction, the neck portion can be lengthened while reducing the size of the resonance box. And since the side wall portion is formed in a flat plate shape extending in a direction intersecting the first direction, the side wall portion can be easily manufactured.

[0018] In the resonance absorber described above, the outer wall may have at least one of a Shore A hardness of 40 or more and 100 or less and a Shore D hardness of 10 or more and 70 or less. In this resonance absorber, since the outer wall has at least one of a Shore A hardness of 40 or more and 100 or less and a Shore D hardness of 10 or more and 70 or less, it is possible to enhance the followability with respect to the inner cavity portion of the tire while suppressing the deformation of the resonance absorber due to centrifugal force.

[0019] In the resonance absorber described above, the outer wall may have an elastomer. In this resonance absorber, since the outer wall has an elastomer, it is possible to enhance the followability with respect to the inner cavity portion of the tire while suppressing the deformation of the resonance absorber due to centrifugal force.

[0020] In the resonance absorber described above, it may further include a flange portion extending outward from the bottom wall portion of the resonance box. In this resonance absorber, since it includes a flange portion extending outward from the bottom wall portion of the resonance box, the flange portion can be pressed against the inner cavity portion of the tire. Thereby, the resonance absorber can be easily attached to the inner cavity portion of the tire.

[0021] In the resonance absorber described above, the resonance box may include a support portion that supports the top wall portion with respect to the bottom wall portion. In this resonance absorber, since the resonance box includes a support portion that supports the top wall portion with respect to the bottom wall portion, it is possible to further suppress the deformation of the top wall portion due to centrifugal force.

[0022] In the resonance absorber described above, the support portion may extend from the bottom wall portion side to the top wall portion side in the hollow portion. In this resonance absorber, since the support portion extends from the bottom wall portion side to the top wall portion side in the hollow portion, it is possible to suppress the deformation of the top wall portion due to centrifugal force while reducing the size of the resonance absorber.

[0023] In the resonance absorber described above, it may include a plurality of resonance boxes. In this resonance absorber, since it includes a plurality of resonance boxes, it is possible to enhance the sound absorption performance of the resonance absorber.

[0024] In the resonance absorber described above, it may further include a connecting wall that connects a plurality of resonance boxes, and adjacent resonance boxes may be separated by the connecting wall. In this resonance absorber, since adjacent resonance boxes are separated by a connecting wall that connects a plurality of resonance boxes, the connecting wall can be pressed against the inner cavity of the tire. Thereby, the resonance absorber can be easily attached to the inner cavity of the tire.

[0025] In the resonance absorber described above, it may further include a double-sided adhesive tape attached to the bottom wall portion. In this resonance absorber, since it includes a double-sided adhesive tape attached to the bottom wall portion, the resonance absorber can be easily attached to the inner cavity of the tire.

[0026] The tire according to the present disclosure includes any one of the above resonance absorbers attached to the inner cavity. In this tire, since it includes the resonance absorber described above, deformation of the resonance absorber due to centrifugal force can be suppressed. That is, it is possible to suppress the shift of the sound absorption frequency characteristics of the resonance absorber to the high-frequency side due to centrifugal force. Thereby, for example, even when a vehicle with a resonance absorber attached to the inner cavity of the tire is traveling at high speed, the resonance sound in the tire cavity can be appropriately reduced.

[0027] In the tire described above, when the frequency of the resonance sound in the tire cavity is F, the speed of light is c, the radius of the inner cavity of the tire is R, the radius of the rim of the wheel assembled to the tire is r, and the pi is π, the resonance absorber may have a Helmholtz resonance structure in which Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the resonance frequency of the resonance sound in the tire cavity calculated from F = c / ((R + r) × π). In this tire, since it has a Helmholtz resonance structure in which Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the resonance frequency of the resonance sound in the tire cavity, the resonance sound in the tire cavity can be reduced.

[0028] The method for attaching a resonance absorber according to the present disclosure is a method for attaching any of the above resonance absorbers to the inner cavity of a tire, and includes a pretreatment step of polishing an attachment region to which the resonance absorber in the inner cavity is to be attached, and an attachment step of attaching the resonance absorber to the attachment region after the pretreatment step.

[0029] In this method for attaching a resonance absorber, since the attachment region is polished before attaching the resonance absorber to the attachment region, even if a release agent is applied to the inner cavity of the tire, the release agent can be removed from the attachment region. Therefore, the attachment strength of the resonance absorber to the attachment region can be increased. Thereby, it is possible to suppress the resonance absorber attached to the attachment region from peeling off from the attachment region.

[0030] In the method for attaching a resonance absorber described above, in the attachment step, the resonance absorber may be attached to the attachment region using a double-sided adhesive tape. In this method for attaching a resonance absorber, since the resonance absorber is attached to the attachment region using a double-sided adhesive tape, the resonance absorber can be easily attached to the attachment region.

Effect of the Invention

[0031] According to the present disclosure, deformation of the resonance absorber due to centrifugal force can be suppressed.

Brief Description of the Drawings

[0032]

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DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, embodiments of the resonance absorber according to the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and duplicate descriptions are omitted. In addition, the numerical range indicated by "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0034] (First Embodiment) FIG. 1 is a schematic cross-sectional view of a tire to which the resonance absorber according to the first embodiment is attached. In the tire 101, cavity resonance may occur in which the internal air resonates when receiving vibrations when passing through road surface irregularities during vehicle travel. The frequency of the cavity resonance is about 200 Hz to 300 Hz, typically about 250 Hz. The resonance absorber 1 according to the present embodiment is attached to the inner cavity portion 102 of the tire 101 in order to efficiently absorb the cavity resonance in the low frequency band. The inner cavity portion 102 is the inner peripheral surface of the tread 103. The resonance absorber 1 is attached to the inner cavity portion 102 of the tire 101 by, for example, a double-sided adhesive tape 12 attached to the attachment surface 11. The attachment surface 11 is the surface (back surface) of the resonance absorber 1 that is attached to the inner cavity portion 102 of the tire 101.

[0035] The double-sided adhesive tape 12 is a tape having adhesiveness on both sides. The double-sided adhesive tape 12 may be configured, for example, such that adhesives (not shown) are disposed on both sides of a base material (not shown), or may be configured such that the base material is impregnated with an adhesive. The double-sided adhesive tape 12 may further include a release sheet disposed on the adhesive. As the double-sided adhesive tape 12, for example, EBISU TAPE #700 manufactured by Ebisu Kasei Co., Ltd. can be used. As the base material, for example, thin paper such as non-woven fabric can be used. As the adhesive, for example, an adhesive such as an acrylic adhesive can be used. The thickness of the double-sided adhesive tape 12 is, for example, 0.05 mm to 1 mm. The double-sided adhesive tape 12 may include a separator disposed on one or both of the adhesives. When the double-sided adhesive tape 12 includes a separator, the separator is peeled off from the adhesive, and the adhesive is attached to the attachment surface 11 of the resonance absorber 1 or the inner cavity portion 102 of the tire 101. Note that the thickness of the double-sided adhesive tape 12 described above is the thickness excluding the separator, that is, the thickness of the base material and the adhesive.

[0036] Here, a method of attaching the resonance absorber 1 will be described. The method of attaching the resonance absorber 1 includes a pretreatment step of polishing the attachment region R of the inner cavity portion 102, and an attachment step of attaching the resonance absorber to the attachment region R after the pretreatment step. The attachment region R is a region where the resonance absorber 1 is attached.

[0037] A mold release agent such as silicone oil is applied to the inner cavity 102 of the tire 101. Therefore, in the pretreatment process, the mold release agent is removed from the attachment region R by polishing the attachment region R. In the pretreatment process, at least the attachment region R may be polished, and regions other than the attachment region R may also be polished. In the present embodiment, the entire circumference of the inner cavity 102 including the attachment region R is polished. The polishing of the attachment region R can be performed, for example, by buffing. In buffing, first, a disk-shaped buff is inserted into the inner cavity of the tire 101. As the buff, for example, a buff brush in which filament materials are planted in the radial direction of the core around a cylindrical core can be used. The filament materials can be made of, for example, metal or synthetic resin. The synthetic resin filament materials may contain polishing abrasive grains such as alumina oxide and silicon carbide. Then, the buff is rotated in a first direction, and the tire is rotated in a second direction opposite to the first direction, and the buff is brought into contact with the inner cavity 102. Thereby, the entire circumference of the inner cavity 102 including the attachment region R is polished (buffed). In the polishing of the attachment region R, for example, the depth of polishing is set to be 3% or more and 30% or less of the thickness of the inner liner layer (not shown) of the tire 101. The inner liner layer is a rubber layer that forms the inner cavity 102.

[0038] In the pasting process, the resonance sound absorber 1 is pasted on the attachment region R using the double-sided adhesive tape 12. In the pasting process, after the double-sided adhesive tape 12 is pasted on the attachment surface 11 of the resonance sound absorber 1, the double-sided adhesive tape 12 may be pasted on the attachment region R of the inner cavity 102, or after the double-sided adhesive tape 12 is pasted on the attachment region R of the inner cavity 102, the double-sided adhesive tape 12 may be pasted on the attachment surface 11 of the resonance sound absorber 1. Thereby, the resonance sound absorber 1 is attached to the inner cavity 102 of the tire 101.

[0039] Referring to FIGS. 2 to 4, the resonance absorber 1 according to the first embodiment will be described. FIG. 2 is a schematic perspective view of the resonance absorber according to the first embodiment. FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. 2. FIG. 4 is a schematic cross-sectional view taken along line IV-IV shown in FIG. 2. Note that FIG. 3 is also a schematic cross-sectional view taken along line III-III shown in FIG. 4. Further, FIG. 4 is also a schematic cross-sectional view taken along line IV-IV shown in FIG. 3. As shown in FIGS. 1 to 4, the resonance absorber 1 according to the present embodiment includes a resonance box 2 having a Helmholtz resonance structure. The resonance box 2 includes a self-supporting outer wall 3, a hollow portion 4 formed inside the outer wall 3, an opening 5 that opens the hollow portion 4 to the outside of the outer wall 3 (outside the resonance box 2), and a hollow neck portion 6 that communicates the opening 5 and the hollow portion 4.

[0040] The outer wall 3 has a degree of self-supporting ability that can maintain its shape in a stationary state. The outer wall 3 is airtight. The outer wall 3 has at least one of a Shore A hardness of 40 or more and 100 or less and a Shore D hardness of 10 or more and 70 or less. In this case, the Shore A hardness of the outer wall 3 may be 50 or more and 80 or less, or may be 60 or more and 70 or less. Also, the Shore D hardness of the outer wall 3 may be 10 or more and 50 or less, or may be 10 or more and 40 or less.

[0041] The Shore A hardness of the outer wall 3 can be measured using a durometer in accordance with JIS K6253-3. For example, GS-709N TYPE A manufactured by Teclock Corporation can be used. The Shore D hardness of the outer wall 3 can be measured using a durometer in accordance with JIS K6253-3. For example, GS-720N TYPE D manufactured by Teclock Corporation can be used. When the allowable number of test piece laminations (3 or less) defined in JIS K6253-3 does not satisfy the specified measurement thickness (6 mm or more), they can be stacked more than 3 sheets and measured at the regulated thickness.

[0042] The material of the outer wall 3 includes, for example, resins such as elastomers such as thermoplastic elastomers, plastics, rubbers, and rubber-like materials.

[0043] Examples of the elastomer material include thermoplastic elastomers such as styrene block copolymer (SBC), polyolefin (TPO), polyurethane (TPU), polyester (TPC), polyamide (TPA), dynamically crosslinked type (TPV), soft polyvinyl chloride (PVC), and acrylic type.

[0044] Examples of the plastic material include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), polyphenylene sulfide (PPS), polyurethane (PU), epoxy resin, phenol resin, and melamine resin.

[0045] Examples of the rubber material include natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), silicone rubber, and urethane rubber.

[0046] Examples of the rubber-like material include an acrylic rubber-like material having UV curability.

[0047] The opening 5 is formed in the outer wall 3 and penetrates the outer wall 3. The opening 5 serves as an inlet for the tire inner cavity resonance sound in the resonance box 2. The shape (cross-sectional shape) of the opening 5 is not particularly limited and can be various shapes such as circular, triangular, rectangular, polygonal, and elliptical. In this embodiment, it is a circular hole. That is, the cross-sectional shape of the opening 5 is circular. The inner diameter of the opening 5 is, for example, about 1 mm to 5 mm.

[0048] The outer wall 3 includes a bottom wall portion 31, a top wall portion 32, a first side wall portion 33, and a second side wall portion 34. The wall thickness of the outer wall 3 is, for example, about 0.1 mm to 2 mm. That is, the wall thickness of each of the bottom wall portion 31, the top wall portion 32, the first side wall portion 33, and the second side wall portion 34 is, for example, about 0.1 mm to 2 mm.

[0049] The bottom wall portion 31 is a portion that forms the mounting surface 11. The bottom wall portion 31 is located on the mounting surface 11 side of the hollow portion 4 and covers the hollow portion 4 from the mounting surface 11 side. The bottom wall portion 31 is formed in a rectangular plate shape that is long in the first direction D1 and short in the second direction D2 orthogonal to the first direction D1. The direction orthogonal to the first direction D1 and the second direction D2 is referred to as the third direction D3. The third direction D3 is also the thickness direction or the height direction of the resonance box 2.

[0050] The top wall portion 32 is a portion that forms the hollow portion 4 between it and the bottom wall portion 31. The top wall portion 32 is located on the side opposite to the mounting surface 11 of the hollow portion 4 and covers the hollow portion 4 from the side opposite to the mounting surface 11. The top wall portion 32 is curved in a convex shape. That the top wall portion 32 is curved in a convex shape means that the top wall portion 32 is curved so as to be convex on the side opposite to the bottom wall portion 31 in the third direction D3, is curved so as to be convex in the direction away from the bottom wall portion 31, or is curved so as to be convex on the side opposite to the hollow portion 4. Specifically described, the top wall portion 32 is formed in an arc shape (arch shape) in a cross section orthogonal to the first direction D1 (a cross section along the second direction D2 and the third direction D3). And both ends of the top wall portion 32 in the second direction D2 are connected to both ends of the bottom wall portion 31 in the second direction D2. That is, the top wall portion 32 is formed in an arc-shaped curved plate shape so as to be convex on the side opposite to the bottom wall portion 31 in the third direction D3 and is connected to one end of the bottom wall portion 31 in the second direction D2 and the other end of the bottom wall portion 31 in the second direction D2.

[0051] The first side wall portion 33 is a portion located at one end of the outer wall 3 in the first direction D1. The first side wall portion 33 is located on one side of the hollow portion 4 in the first direction D1 and covers the hollow portion 4 from one side in the first direction D1. An opening 5 is formed in the first side wall portion 33. That is, the opening 5 penetrates the first side wall portion 33 and communicates with the hollow portion 4. The first side wall portion 33 is formed in a flat plate shape extending in a direction intersecting the first direction D1 and is connected to one end of the bottom wall portion 31 and the top wall portion 32 in the first direction D1. In the present embodiment, the first side wall portion 33 is formed in a flat plate shape extending in a direction orthogonal to the first direction D1 (a direction along the second direction D2 and the third direction D3).

[0052] The second side wall portion 34 is a portion located at the other end of the outer wall 3 in the first direction D1. The other side of the outer wall 3 in the first direction D1 is also the side opposite to the first side wall portion 33 of the outer wall 3 in the first direction D1. The second side wall portion 34 is located on the other side of the hollow portion 4 in the first direction D1 and covers the hollow portion 4 from the other side in the first direction D1. The second side wall portion 34 is formed in a flat plate shape extending in a direction intersecting the first direction D1 and is connected to the other end of the bottom wall portion 31 and the top wall portion 32 in the first direction D1. The second side wall portion 34 is formed, for example, in a flat plate shape extending in a direction orthogonal to the first direction D1 (a direction along the second direction D2 and the third direction D3).

[0053] At least a part of the neck portion 6 is disposed inside the outer wall 3. In the present embodiment, the entire neck portion 6 is disposed inside the outer wall 3. The proximal end and the distal end of the neck portion 6 are open ends where the hollow portion 61 of the neck portion 6 is exposed. The proximal end of the neck portion 6 is connected to the opening 5, and the hollow portion 61 of the neck portion 6 is open to the outside of the outer wall 3 (outside the resonance box 2) from the opening 5 at the proximal end of the neck portion 6. The distal end of the neck portion 6 is located inside the hollow portion 4, and the hollow portion 61 of the neck portion 6 is open to the hollow portion 4 at the distal end of the neck portion 6.

[0054] The neck portion 6 has airtightness, similar to the resonance box 2. The neck portion 6 has at least one of the same Shore A hardness and Shore D hardness as the resonance box 2. The material of the neck portion 6 can be the same as that of the resonance box 2.

[0055] The hollow portion 61 of the neck portion 6 has, for example, a cross section equal to or larger than that of the opening 5. By increasing the extension length of the neck portion 6, the resonance frequency of the resonance box 2 can be lowered. That is, by increasing the extension length of the neck portion 6, the resonance sound in the low frequency range can be reduced. The extension length of the neck portion 6 is the length of the extension axis of the neck portion 6 from the proximal end to the distal end of the neck portion 6.

[0056] The neck portion 6 is disposed on the bottom wall portion 31 so as to extend along the bottom wall portion 31. The neck portion 6 is, for example, integrated (formed integrally) with the bottom wall portion 31 and connected to the bottom wall portion 31. The neck portion 6 extends in the first direction D1, but the extension direction, extension shape, etc. of the neck portion 6 are not particularly limited.

[0057] The resonance sound absorber 1 configured as described above can be manufactured, for example, by injection molding, extrusion molding, 3D printer shaping, salt aggregation method, or the like.

[0058] As described above, in the resonance sound absorber 1 according to the present embodiment, since the resonance box 2 having the self-supporting outer wall 3, the hollow portion 4 formed inside the outer wall 3, and the opening 5 formed in the outer wall 3 and communicating with the hollow portion 4 is provided, the resonance sound absorber 1 can function as a Helmholtz resonator. Further, since the outer wall 3 of the resonance box 2 has self-supporting properties, it is possible to maintain a self-supporting state without filling the hollow portion 4 with a filler such as a porous sound absorber. Note that the hollow portion 4 may be filled with a filler such as a porous sound absorber. And, since the top wall portion 32 of the self-supporting outer wall 3 is curved in a convex shape, it is easy to receive the force toward the bottom wall portion 31. Thereby, it is possible to suppress the resonance sound absorber 1 from being deformed by the centrifugal force generated when a vehicle in which the resonance sound absorber 1 is attached to the inner cavity portion 102 of the tire 101 travels at high speed.

[0059] In addition, in this resonance absorber 1, since the top wall portion 32 is connected to the bottom wall portion 31, the supporting force of the top wall portion 32 by the bottom wall portion 31 becomes high. Thereby, deformation of the resonance absorber 1 due to centrifugal force can be further suppressed.

[0060] In addition, in this resonance absorber 1, since the resonance box 2 is provided with a hollow neck portion 6 that communicates the opening 5 and the hollow portion 4, the resonance frequency of Helmholtz resonance can be adjusted by adjusting the length of the neck portion 6. And by making the neck portion 6 longer, Helmholtz resonance with a resonance frequency in the low frequency range can be generated, so that resonance sound in the low frequency range such as tire cavity resonance sound can be reduced.

[0061] In addition, in this resonance absorber 1, since at least a part of the neck portion 6 is disposed inside the outer wall 3, while making it possible to generate Helmholtz resonance with a resonance frequency in the low frequency range by making the neck portion 6 longer, miniaturization of the resonance absorber 1 can be achieved.

[0062] In addition, in this resonance absorber 1, since the neck portion 6 is disposed on the bottom wall portion 31 so as to extend along the bottom wall portion 31, movement of the neck portion 6 due to centrifugal force can be suppressed.

[0063] In addition, in this resonance absorber 1, since the resonance box 2 is configured to be long in the first direction D1 and the opening 5 is formed at an end of the outer wall 3 in the first direction D1, the neck portion 6 can be made longer while achieving miniaturization of the resonance box 2.

[0064] In addition, in this resonance absorber 1, since the top wall portion 32 is formed in an arc shape in a cross section orthogonal to the first direction D1, deformation of the top wall portion 32 due to centrifugal force can be effectively suppressed.

[0065] In addition, in this resonance sound absorber 1, since the opening 5 is formed in the first side wall portion 33 located at the end portion in the first direction D1, the neck portion 6 can be lengthened while reducing the size of the resonance box 2. And since the first side wall portion 33 is formed in a flat plate shape extending in a direction intersecting the first direction D1, the first side wall portion 33 can be easily manufactured.

[0066] In addition, in this resonance sound absorber 1, since the outer wall 3 has at least one of a Shore A hardness of 40 or more and 100 or less and a Shore D hardness of 10 or more and 70 or less, it is possible to enhance the followability with respect to the inner cavity portion 102 of the tire 101 while suppressing the deformation of the resonance sound absorber 1 due to centrifugal force.

[0067] In addition, in this resonance sound absorber 1, since the outer wall 3 has an elastomer, it is possible to enhance the followability with respect to the inner cavity portion 102 of the tire 101 while suppressing the deformation of the resonance sound absorber 1 due to centrifugal force.

[0068] In addition, in this resonance sound absorber 1, since it is provided with the double-sided adhesive tape 12 attached to the bottom wall portion 31, the resonance sound absorber 1 can be easily attached to the inner cavity portion 102 of the tire 101.

[0069] In the tire 101 according to the present embodiment, since the above-described resonance sound absorber 1 is provided, the deformation of the resonance sound absorber 1 due to centrifugal force can be suppressed. That is, it is possible to suppress the shift of the sound absorption frequency characteristics of the resonance sound absorber 1 to the high-frequency side due to centrifugal force. Thereby, for example, even when a vehicle in which the resonance sound absorber 1 is attached to the inner cavity portion 102 of the tire 101 is traveling at high speed, the resonance sound in the tire inner cavity can be appropriately reduced.

[0070] Here, as shown in FIG. 1, let the frequency of the tire cavity resonance sound be F, the speed of light be c, the radius of the inner cavity portion 102 of the tire 101 be R, the radius of the rim 105 of the wheel 104 assembled to the tire 101 be r, and the pi be π. In this case, the frequency of the tire cavity resonance sound is calculated by F = c / ((R + r) × π). The resonance sound absorber 1 preferably has a Helmholtz resonance structure in which Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the frequency of the tire cavity resonance sound calculated from F = c / ((R + r) × π).

[0071] The Helmholtz resonance structure is a structure including components of a Helmholtz resonator that resonates with the sound incident from the opening. In the resonance sound absorber 1, the Helmholtz resonance structure is constituted by the resonance box 2. That is, in the resonance box 2, since the non-ventilation neck portion 6 communicates the opening 5 and the hollow portion 4, the resonance frequency of the resonance sound absorber 1 functioning as a Helmholtz resonator changes depending on the extension length of the neck portion 6, the inner diameter of the opening 5, and the like. For example, the larger the extension length of the neck portion 6, the lower the resonance frequency. Also, the smaller the inner diameter of the opening 5, the lower the resonance frequency. Therefore, it is preferable that the resonance sound absorber 1 is adjusted such that Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the frequency of the tire cavity resonance sound calculated from F = c / ((R + r) × π).

[0072] Thus, by providing a Helmholtz resonance structure in which Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the frequency of the tire cavity resonance sound, the tire cavity resonance sound can be reduced.

[0073] FIG. 23 is a diagram for explaining a method of calculating the resonance frequency of the Helmholtz resonance structure. The resonance frequency of the Helmholtz resonance structure that resonates with the sound incident from the opening 5 can be adjusted from various dimensions of the hollow portion 4 according to this calculation method.

[0074] In Fig. 23, V is the volume of the hollow portion 4. When the neck portion 6 extends in the hollow portion 4, V is the volume obtained by subtracting the volume of the neck portion 6. As shown in the third embodiment described later, when a porous sound absorber is disposed in the hollow portion 4, V is the volume of the hollow portion 4 including the porous sound absorber. α is the area of the opening 5 when viewed from the thickness direction of the outer wall. δ is the opening end correction. For example, when the shape of the opening 5 is circular, δ can be calculated as 0.8 times the diameter of the opening 5. When the shape of the opening 5 is not circular, δ can be calculated as 0.8 times the diameter of a perfect circle having the same area as the area of the opening 5. L is the depth of the opening 5, that is, the extending length of the neck portion 6 (hollow portion).

[0075] (Second Embodiment) Referring to Fig. 5, the resonance sound absorber 1A according to the second embodiment will be described. The second embodiment is basically the same as the first embodiment (see Figs. 2 to 4), and is different from the first embodiment only in that it further includes a flange portion. Therefore, hereinafter, only matters different from the first embodiment will be described, and description of matters the same as those in the first embodiment will be omitted.

[0076] Fig. 5 is a schematic cross-sectional view of the resonance sound absorber according to the second embodiment. As shown in Fig. 5, the resonance sound absorber 1A according to the present embodiment includes a resonance box 2 and a flange portion 7A.

[0077] The flange portion 7A is a portion that forms a part of the mounting surface 11. The flange portion 7A extends outward from the bottom wall portion 31 of the resonance box 2. Specifically, the flange portion 7A extends so as to spread from the bottom wall portion 31 of the outer wall 3 of the resonance box 2 along the mounting surface 11. The width of the flange portion 7A is, for example, about 1 mm or more and 20 mm or less. The width of the flange portion 7A is the dimension in the direction away from the bottom wall portion 31.

[0078] As described above, in the resonance absorber 1A according to the present embodiment, since the flange portion 7A extending outward from the bottom wall portion 31 to the outside of the resonance box 2 is provided, the flange portion 7A can be pressed against the inner cavity portion 102 of the tire 101. Thereby, the resonance absorber 1A can be easily attached to the inner cavity portion 102 of the tire 101.

[0079] (Third Embodiment) Referring to FIG. 6, the resonance absorber 1B according to the third embodiment will be described. The third embodiment is basically the same as the first embodiment (see FIGS. 2 to 4), and is different from the first embodiment only in that it further includes a porous sound absorber. For this reason, only matters different from the first embodiment will be described below, and description of matters the same as those in the first embodiment will be omitted.

[0080] FIG. 6 is a schematic cross-sectional view of the resonance absorber according to the third embodiment. As shown in FIG. 6, the resonance absorber 1B according to the present embodiment includes a resonance box 2B in which a porous sound absorber 8B is disposed in the hollow portion 4.

[0081] The porous sound absorber 8B is disposed around the neck portion 6 of the hollow portion 4 and is not disposed in the hollow portion 61 of the neck portion 6.

[0082] The porous sound absorber 8B is formed, for example, by foam molding of a resin material such as plastic or rubber. Examples of the plastic material include foamed polyurethane. Either rigid foamed polyurethane or soft foamed polyurethane may be used. As the manufacturing method of foamed polyurethane, a general method can be used. For example, by mixing a polyol and a polyisocyanate with a foaming agent, a foam stabilizer, a catalyst, etc., filling the mixture into a mold, and foaming and curing it, the porous sound absorber 8B can be obtained.

[0083] Examples of the rubber material include rubber materials obtained from latex, such as natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber (CR). By foaming and solidifying these rubber materials, the porous sound absorber 8B can be obtained.

[0084] The pore diameter of the porous sound absorber 8B is, for example, 1 μm or less, preferably 500 μm or less. The open porosity of the porous sound absorber 8B (the ratio of the total area of pores to the area of the porous sound absorber on the surface of the porous sound absorber 8B) is, for example, about 65% to 99%, preferably about 80% to 95%. The pore diameter and the open porosity can be measured, for example, using a computed tomography (CT scan) device using X-rays. For calculating the pore diameter, the average value of the diameters of a plurality (for example, 100) of pores extracted based on the observation image can be used. For calculating the open porosity, the division value obtained by dividing the total area of all pores extracted based on the observation image by the area of the porous sound absorber can be used.

[0085] As described above, in the resonance sound absorber 1B according to the present embodiment, since the porous sound absorber 8B is disposed in the hollow portion 4, it is possible to reduce the sound in the high frequency range.

[0086] (Fourth Embodiment) With reference to FIGS. 7 and 8, the resonance sound absorber 1C according to the fourth embodiment will be described. The fourth embodiment is basically the same as the first embodiment (see FIGS. 2 to 4), and is different from the first embodiment only in that the shapes of the bottom wall portion, the first side wall portion, and the second side wall portion of the outer wall of the resonance box are different. Therefore, below, only the matters different from the first embodiment will be described, and the description of the matters the same as the first embodiment will be omitted.

[0087] FIG. 7 is a schematic perspective view of the resonance sound absorber according to the fourth embodiment. FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII shown in FIG. 7. As shown in FIGS. 7 and 8, the outer wall 3C of the resonance box 2C of the resonance sound absorber 1C according to the present embodiment includes a bottom wall portion 31C, a top wall portion 32, a first side wall portion 33C, and a second side wall portion 34C.

[0088] The bottom wall portion 31C is formed in an oval shape that is long in the first direction D1. That is, both end edges of the bottom wall portion 31C in the first direction D1 are curved convexly. The fact that both end edges of the bottom wall portion 31C in the first direction D1 are curved convexly means that both end edges in the first direction D1 are curved so as to be convex in a direction separating from each other in the first direction D1. For example, both end portions of the bottom wall portion 31C in the first direction D1 are formed in a semi-circular shape, and both end edges of the bottom wall portion 31C in the first direction D1 are formed in a semi-circular arc shape, for example.

[0089] The first side wall portion 33C is a portion located at one end of the outer wall 3C in the first direction D1. The first side wall portion 33C is located on one side of the hollow portion 4 in the first direction D1 and covers the hollow portion 4 from one side in the first direction D1. An opening 5 is formed in the first side wall portion 33C. That is, the opening 5 communicates with the hollow portion 4 by penetrating the first side wall portion 33C. And the first side wall portion 33C is curved convexly. The fact that the first side wall portion 33C is curved convexly means that the first side wall portion 33C is curved so as to be convex on the side opposite to the bottom wall portion 31 in the third direction D3 and on the side opposite to the second side wall portion 33D in the first direction D1, that it is curved so as to be convex in a direction separating from the bottom wall portion 31 and on the side opposite to the second side wall portion 33D in the first direction D1, or that it is curved so as to be convex on the side opposite to the hollow portion 4. Specifically described, the first side wall portion 33C is formed in an arc shape (arch shape) in a cross section orthogonal to the first direction D1 (a cross section along the second direction D2 and the third direction D3). Also, the first side wall portion 33C is formed in an arc shape (arch shape) in a cross section orthogonal to the third direction D3 (a cross section along the first direction D1 and the second direction D2). And the end portion of the first side wall portion 33C is connected to the top wall portion 32 and the bottom wall portion 31C.

[0090] The second side wall portion 34C is a portion located at the other end of the outer wall 3C in the first direction D1. The other side of the outer wall 3C in the first direction D1 is also the side opposite to the first side wall portion 33C of the outer wall 3C in the first direction D1. The second side wall portion 34C is located on the other side of the hollow portion 4 in the first direction D1 and covers the hollow portion 4 from the other side in the first direction D1. And the second side wall portion 34C is curved in a convex shape. That the second side wall portion 34C is curved in a convex shape means that the second side wall portion 34C is curved so as to be convex on the side opposite to the bottom wall portion 31 in the third direction D3 and on the side opposite to the second side wall portion 33D in the first direction D1, that it is curved so as to be convex in the direction away from the bottom wall portion 31 and on the side opposite to the second side wall portion 33D in the first direction D1, or that it is curved so as to be convex on the side opposite to the hollow portion 4. Specifically described, the second side wall portion 34C is formed in an arc shape (arch shape) in a cross section orthogonal to the first direction D1 (a cross section along the second direction D2 and the third direction D3). Also, the second side wall portion 34C is formed in an arc shape (arch shape) in a cross section orthogonal to the third direction D3 (a cross section along the first direction D1 and the second direction D2). And the end portion of the second side wall portion 34C is connected to the top wall portion 32 and the bottom wall portion 31C.

[0091] As described above, in the resonance absorber 1C according to the present embodiment, since the opening 5 is formed in the first side wall portion 33C located at the end in the first direction D1, the neck portion 6 can be lengthened while reducing the size of the resonance box 2C. And since the first side wall portion 33C and the second side wall portion 34C are curved in a convex shape, the non-uniformity of the rigidity in the outer wall 3C can be alleviated. For this reason, the deformation of the resonance absorber 1C due to centrifugal force can be further suppressed.

[0092] (Fifth Embodiment) With reference to FIGS. 9 to 11, the resonance absorber 1D according to the fifth embodiment will be described. The fifth embodiment is basically the same as the first embodiment (see FIGS. 2 to 4), and is different from the first embodiment only in that the resonance box further includes a support portion. For this reason, hereinafter, only the matters different from the first embodiment will be described, and the description of the matters the same as the first embodiment will be omitted.

[0093] FIG. 9 is a schematic cross-sectional view of the resonance absorber according to the fifth embodiment. FIG. 10 is a schematic cross-sectional view taken along the line X-X shown in FIG. 9. FIG. 11 is a schematic cross-sectional view taken along the line XI-XI shown in FIG. 9. Note that FIG. 9 is a cross-sectional view corresponding to FIG. 3 and is also a schematic cross-sectional view taken along the line IX-IX shown in FIGS. 10 and 11. As shown in FIGS. 9 to 11, the resonance box 2D of the resonance absorber 1D according to the present embodiment includes an outer wall 3, a hollow portion 4, an opening 5, a neck portion 6, and a support portion 9D.

[0094] The support portion 9D is a portion for supporting the top wall portion 32 with respect to the bottom wall portion 31. The support portion 9D extends from the bottom wall portion 31 side to the top wall portion 32 side in the hollow portion 4. Specifically described, the support portion 9D is formed of a plate-like rib and extends in the third direction D3 from the neck portion 6 to the top wall portion 32. That is, the support portion 9D supports the top wall portion 32 with respect to the bottom wall portion 31 via the neck portion 6. The support portion 9D has a shape that can maintain the hollow portion 4 as one space. For example, the support portion 9D has a shape in which a portion between the neck portion 6 and the second side wall portion 34 is cut out. The support portion 9D may support the top wall portion 32 only in a part of the first direction D1, or may support the top wall portion 32 over the entire first direction D1. For example, the support portion 9D may be connected to the top wall portion 32 over the entire first direction D1 so as to support the top wall portion 32 over the entire first direction D1.

[0095] As described above, in the resonance absorber 1D according to the present embodiment, since the resonance box 2D includes the support portion 9D that supports the top wall portion 32 with respect to the bottom wall portion 31, deformation of the top wall portion 32 due to centrifugal force can be further suppressed.

[0096] Further, in this resonance absorber 1D, since the support portion 9D extends from the bottom wall portion 31 side to the top wall portion 32 side in the hollow portion 4, it is possible to suppress deformation of the top wall portion 32 due to centrifugal force while reducing the size of the resonance absorber 1D.

[0097] (Sixth Embodiment) With reference to FIGS. 12 and 13, the resonance absorber 1E according to the sixth embodiment will be described. The sixth embodiment is basically the same as the first embodiment (see FIGS. 2 to 4), and is different from the first embodiment only in that it includes a plurality of resonance boxes. For this reason, below, only the matters different from the first embodiment will be described, and the description of the matters the same as the first embodiment will be omitted.

[0098] FIG. 12 is a schematic perspective view of the resonance absorber according to the sixth embodiment. FIG. 13 is a schematic cross-sectional view taken along line XIII-XIII shown in FIG. 12. As shown in FIGS. 12 and 13, the resonance absorber 1E according to the present embodiment includes a plurality of resonance boxes 2 and a connecting wall 10E.

[0099] The connecting wall 10E is a part that connects the plurality of resonance boxes 2. The connecting wall 10E connects the plurality of resonance boxes 2 such that, for example, the plurality of resonance boxes 2 are arranged in the second direction D2. The thickness, Shore A hardness, Shore D hardness, material, etc. of the connecting wall 10E can be the same as those of the resonance box 2. The connecting wall 10E includes a connecting wall portion 10Ea disposed between adjacent resonance boxes 2 and a flange wall portion 10Eb disposed around the plurality of resonance boxes 2. The number of resonance boxes 2 connected by the connecting wall 10E is not particularly limited, but can be, for example, 1 to 10. The separation distance between adjacent resonance boxes 2 is, for example, about 2 mm to 10 mm.

[0100] As described above, in the resonance absorber 1E according to the present embodiment, since a plurality of resonance boxes 2 are provided, the sound absorption performance of the resonance absorber 1E can be enhanced.

[0101] Further, in this resonance absorber 1E, since adjacent resonance boxes 2 are separated by a connecting wall 10E that connects the plurality of resonance boxes 2, the connecting wall portion 10Ea can be pressed against the inner cavity portion 102 of the tire 101. Thereby, the resonance absorber 1E can be easily attached to the inner cavity portion 102 of the tire 101.

[0102] Further, in this resonance absorber 1E, since the flange wall portion 10Eb is arranged around the plurality of resonance boxes 2, the flange wall portion 10Eb can be pressed against the inner cavity portion 102 of the tire 101. Thereby, the resonance absorber 1E can be easily attached to the inner cavity portion 102 of the tire 101.

[0103] The present disclosure is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present disclosure.

[0104] For example, the mounting surface of the resonance absorber may be formed in a flat shape or a curved shape. FIG. 14 is a schematic front view showing a resonance absorber of a modified example. The resonance absorber 1F shown in FIG. 14 is basically the same as the resonance absorber 1 (see FIGS. 2 to 4) according to the first embodiment, but the mounting surface 11 of the bottom wall portion 31 is formed in an arc-shaped curve along the inner cavity portion 102 of the tire 101. FIG. 15 is a schematic front view showing a resonance absorber of a modified example. The resonance absorber 1G shown in FIG. 15 is basically the same as the resonance absorber 1E (see FIGS. 12 and 13) according to the sixth embodiment, but the mounting surfaces 11 of the bottom wall portions 31 and the connecting walls 10E of the respective resonance boxes 2 are formed in an arc-shaped curve along the inner cavity portion 102 of the tire 101. Thus, by the mounting surface being curved in an arc shape, the ease of mounting to the inner cavity of the tire is improved. In these cases, it may be considered that the mounting surface 11 is formed in an arc-shaped curve by changing the thickness of the bottom wall portion 31 and the connecting wall 10E, or the bottom wall portion 31 and the connecting wall 10E may be curved without changing the thickness of the bottom wall portion 31 and the connecting wall 10E so that the mounting surface 11 is formed in an arc-shaped curve.

[0105] Further, for example, the top wall portion may not be directly connected to the bottom wall portion and may be connected to the bottom wall portion via other parts. FIG. 16 is a schematic cross-sectional view of a resonance absorber according to a modified example. The resonance absorber 1H shown in FIG. 16 is basically the same as the resonance absorber 1 (see FIGS. 2 to 4) according to the first embodiment, but on the outer wall 3H of the resonance box 2H, the top wall portion 32 is connected to the bottom wall portion 31 via an upright wall portion 35H formed in a flat plate shape. The upright wall portion 35H extends in a direction orthogonal to the second direction D2 (the direction along the first direction D1 and the third direction D3), and is connected to both ends of the top wall portion 32 in the second direction D2 and both ends of the bottom wall portion 31 in the second direction D2.

[0106] Further, for example, the shape of the outer wall, the positions of the opening and the neck portion, the shape of the support portion, etc. are not particularly limited and can be variously deformed. FIGS. 17(a), 17(b), 18(a), 18(b), 19(a), 19(b), 20(a), 20(b), 21(a), 21(b), 22(a), and 22(b) are schematic cross-sectional views of resonance absorbers according to modified examples.

[0107] In the resonance box 2I of the resonance absorber 1I shown in FIG. 17(a), the opening 5 and the neck portion 6 are arranged at the end of the hollow portion 4 in the second direction D2.

[0108] In the resonance box 2J of the resonance absorber 1J shown in FIG. 17(b), the outer wall 3J protrudes on one side in the second direction D2, and the opening 5 and the neck portion 6 are arranged inside the protruding portion of the outer wall 3J.

[0109] In the resonance box 2K of the resonance absorber 1K shown in FIG. 18(a), the opening 5 and the neck portion 6 are arranged at the end of the hollow portion 4 in the second direction D2. Further, the support portion 9K extends from the bottom wall portion 31 to the top wall portion 32 without passing through the neck portion 6 at the central portion of the hollow portion 4 in the second direction D2.

[0110] In the resonance box 2L of the resonance absorber 1L shown in Fig. 18(b), the outer wall 3L protrudes on one side in the second direction D2, and the opening 5 and the neck portion 6 are disposed inside the protruding portion of the outer wall 3L. Further, the support portion 9L extends from the bottom wall portion 31 to the top wall portion 32 without passing through the neck portion 6 at the central portion in the second direction D2 of the hollow portion 4.

[0111] In the resonance box 2M of the resonance absorber 1M shown in Fig. 19(a), the support portion 9M is formed in a cross shape and extends from the neck portion 6 to the top wall portion 32.

[0112] In the resonance box 2N of the resonance absorber 1N shown in Fig. 19(b), the support portion 9N is formed in a V shape and extends from the neck portion 6 to the top wall portion 32.

[0113] In the resonance box 2O of the resonance absorber 1O shown in Fig. 20(a), the support portion 9O is formed in an inverted V shape and extends from the neck portion 6 to the top wall portion 32.

[0114] In the resonance box 2P of the resonance absorber 1P shown in Fig. 20(b), the support portion 9P is formed in a radial shape and extends from the neck portion 6 to the top wall portion 32.

[0115] In the resonance box 2Q of the resonance absorber 1Q shown in Fig. 21(a), the support portion 9Q is formed in an I shape and extends from the bottom wall portion 31 to the top wall portion 32 so as to avoid the neck portion 6.

[0116] In the resonance box 2R of the resonance absorber 1R shown in Fig. 21(b), the support portion 9R is formed in an H shape and extends from the bottom wall portion 31 to the top wall portion 32 so as to sandwich the neck portion 6.

[0117] In the resonance box 2S of the resonance absorber 1S shown in Fig. 22(a), the support portion 9S is formed in a V shape and extends from the connection portion between the bottom wall portion 31 and the neck portion 6 to the top wall portion 32 so as to sandwich the neck portion 6.

[0118] In the resonance box 2T of the resonance absorber 1T shown in Fig. 22(b), the support portion 9T is formed in an inverted V shape and extends from the bottom wall portion 31 to the top wall portion 32 so as to sandwich the neck portion 6.

[0119] Further, for example, when attaching a plurality of resonance absorbers to a tire, two or more resonance absorbers that generate Helmholtz resonance with different resonance frequencies may be attached to the tire.

[0120] Further, for example, the neck portion may be arranged so that the neck portion also extends outside the outer wall. In this case, the resonance frequency of the resonance absorber can be adjusted according to the total length of the neck portion inside and outside the outer wall.

[0121] Further, for example, each of the above embodiments and each modification can be combined as appropriate. For example, the support portions of the fifth embodiment shown in Figs. 9 to 11 and the modifications shown in Figs. 18 to 22 may be applied to other embodiments and modifications.

[0122] By laying at least one resonance body formed by connecting a single or a plurality of resonance boxes in the tire, the resonance sound in the tire cavity can be reduced. When laying two or more resonance bodies formed by connecting a single or a plurality of resonance boxes, they may be laid in an adjacent state, or they may be laid with an interval as an intermittent arrangement. However, from the viewpoint of the weight balance in the circumferential direction of the tire, the intermittent arrangement is preferable.

Explanation of Signs

[0123] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M, 1N, 1O, 1P, 1Q, 1R, 1S, 1T... resonance absorber, 2, 2B, 2C, 2D, 2H, 2I, 2J, 2K, 2L, 2M, 2N, 2O, 2P, 2Q, 2R, 2S, 2T... resonance box, 3, 3C, 3H, 3J, 3L... outer wall, 4... hollow part, 5... opening, 6... neck part, 7A... flange part, 8B... porous sound absorber, 9D, 9K, 9L, 9M, 9N, 9O, 9P, 9Q, 9R, 9S, 9T... support part, 10E... connecting wall, 10Ea... connecting wall part, 10Eb... flange wall part, 11... mounting surface, 12... double-sided adhesive tape, 31, 31C... bottom wall part, 32... top wall part, 33, 33C... first side wall part, 34, 34C... second side wall part, 35H... upright wall part, 61... hollow portion, 101... tire, 102... inner cavity part, 103... tread, 104... wheel, 105... rim, D1... first direction, D2... second direction, D3... third direction, R... mounting area.

Claims

1. A resonance sound absorber attached to the inner cavity of a tire, which is the inner peripheral surface of the tire tread, comprising: a resonance box having a self-supporting outer wall, a hollow portion formed inside the outer wall, an opening that opens the hollow portion to the outside of the outer wall, and a hollow neck portion that communicates the opening and the hollow portion; the outer wall includes a bottom wall portion attached to the inner cavity portion and a top wall portion that forms the hollow portion between the bottom wall portion; the top wall portion is curved convexly; Resonance sound absorber.

2. the top wall portion is connected to the bottom wall portion; The resonance sound absorber according to claim 1.

3. at least a part of the neck portion is disposed inside the outer wall; The resonance sound absorber according to claim 1.

4. the neck portion is disposed on the bottom wall portion so as to extend along the bottom wall portion; The resonance sound absorber according to claim 1.

5. the resonance box is configured to be long in a first direction; the opening is formed at an end of the outer wall in the first direction; The resonance sound absorber according to claim 1.

6. the top wall portion is formed in an arc shape in a cross section perpendicular to the first direction; The resonance sound absorber according to claim 5.

7. the outer wall has a side wall portion located at an end in the first direction where the opening is formed; the side wall portion is curved convexly; The resonance sound absorber according to claim 5.

8. the outer wall has a side wall portion located at an end in the first direction where the opening is formed; the side wall portion is formed in a flat plate shape extending in a direction intersecting the first direction; The resonance sound absorber according to claim 5.

9. the outer wall has at least one of a Shore A hardness of 40 or more and 100 or less and a Shore D hardness of 10 or more and 70 or less; The resonance sound absorber according to claim 1.

10. the outer wall has an elastomer; The resonance sound absorber according to claim 1.

11. further comprising a flange portion extending outward from the bottom wall portion of the resonance box; The resonance sound absorber according to claim 1.

12. the resonance box includes a support portion that supports the top wall portion with respect to the bottom wall portion; the support portion extends from the bottom wall portion side to the top wall portion side in the hollow portion; The resonance sound absorber according to claim 1.

13. comprising a plurality of the resonance boxes; The resonance sound absorber according to claim 1.

14. further comprising a connecting wall that connects a plurality of the resonance boxes; The adjacent resonance boxes are separated by the connecting wall. The resonance sound absorber according to claim 13.

15. Further comprising a double-sided adhesive tape attached to the bottom wall portion. The resonance sound absorber according to claim 1.

16. The neck portion extends from the outer wall into the hollow portion. The resonance sound absorber according to claim 1.

17. The neck portion extends from the side wall portion into the hollow portion. The resonance sound absorber according to claim 7.

18. The neck portion extends along the opening. The resonance sound absorber according to claim 1.

19. The top wall portion is curved convexly toward the rotation center side of the tire. The resonance sound absorber according to claim 1.

20. Comprising the resonance sound absorber according to any one of claims 1 to 19, attached to the inner cavity portion. Tire.

21. When the frequency of the tire inner cavity resonance sound is F, the speed of light is c, the radius of the inner cavity portion of the tire is R, the radius of the rim of the wheel assembled to the tire is r, and the pi is π, the resonance sound absorber has a Helmholtz resonance structure in which Helmholtz resonance occurs at a resonance frequency within the range of ±100 Hz of the frequency of the tire inner cavity resonance sound calculated from F = c / ((R + r) × π). The tire according to claim 20.

22. A method for attaching a resonance sound absorber, which attaches the resonance sound absorber according to any one of claims 1 to 19 to the inner cavity portion of a tire, A pretreatment step of polishing the attachment region where the resonance sound absorber in the inner cavity portion is to be attached, A pasting step of pasting the resonance sound absorber to the attachment region after the pretreatment step. Method for attaching a resonance sound absorber.

23. In the pasting step, the resonance sound absorber is pasted to the attachment region using a double-sided adhesive tape. The method for attaching a resonance sound absorber according to claim 22.

Images