Sound-absorbing unit

Abstract

This sound-absorbing unit is mounted inside the cavity of a tire. The sound-absorbing unit comprises a resonance sound absorber and a support body that supports the resonance sound absorber. The support body has a first holding part and a second holding part. The first holding part holds one end part of the resonator by having inserted thereinto a step portion provided at the one end part of the resonator. The second holding part holds the other end part opposite from the one end part of the resonator by having inserted thereinto a step portion provided at the other end part of the resonator.

Description

Sound-absorbing unit

[0001] The present disclosure relates to a sound-absorbing unit provided in the inner cavity of a tire.

[0002] For example, as described in Japanese Patent Application Laid-Open No. 2021-067767, a resonance sound absorber that absorbs sound using the principle of Helmholtz resonance is known. This resonance sound absorber absorbs the resonance sound generated in the inner cavity of the tire. Such a resonance sound absorber includes a resonator in which a hollow portion is formed inside and an opening that communicates the hollow portion with the outside.

[0003] It is conceivable to attach the resonance sound absorber described above to the mounting surface in the inner cavity of the tire using a support. In this situation, when the resonance sound absorber is attached using a support, strong fixation is required.

[0004] Therefore, the present disclosure will describe a sound-absorbing unit capable of firmly fixing a resonance sound absorber to a support.

[0005] One aspect of the present disclosure is a sound-absorbing unit attached in the inner cavity of a tire, including a resonance sound absorber that absorbs sound in the inner cavity, and a support attached to the mounting surface in the inner cavity and supporting the resonance sound absorber with respect to the mounting surface. The resonance sound absorber has a resonator in which a hollow portion is provided inside and an opening that opens the hollow portion to the outside. The resonator is configured to be long in a first direction along a first axis. The support has a first holding portion and a second holding portion. The first holding portion is fitted into a stepped portion provided at one end of the resonator in the first direction to hold one end of the resonator. The second holding portion is fitted into a stepped portion provided at the other end opposite to one end of the resonator in the first direction to hold the other end of the resonator.

[0006] In this sound-absorbing unit, the stepped portions at both ends of the resonator in the longitudinal direction are inserted inside the first and second holding portions of the support. The first and second holding portions surround both ends of the resonator around the first axis. Therefore, even if the resonant sound absorber attempts to move in a direction intersecting the first direction with respect to the support, the sound-absorbing unit can hold the resonant sound absorber with the first and second holding portions. Furthermore, because both ends of the resonator are stepped portions, if the resonant sound absorber attempts to move along the first direction, the first or second holding portion will catch on the step of the resonator. Therefore, in the sound-absorbing unit, the movement of the resonant sound absorber in the first direction can be restricted by the first and second holding portions of the support. In this way, the sound-absorbing unit can firmly fix the resonant sound absorber to the support.

[0007] In the above sound-absorbing unit, the resonator has a first part which is the portion at one end in the first direction, a second part which is the portion at the other end in the first direction, and an intermediate part which is the portion between the first part and the second part. The circumference of the outer surface of the intermediate part around the first axis is longer than the circumference of the outer surface of the first part and the circumference of the outer surface of the second part around the first axis. A stepped portion provided at one end of the resonator in the first direction is formed by the intermediate part and the first part, and a stepped portion provided at the other end of the resonator in the first direction is formed by the intermediate part and the second part. A first retaining part may hold the first part by inserting the first part inside it, and a second retaining part may hold the second part by inserting the second part inside it. For example, if the resonant sound absorber tries to move along the first direction, the first retaining part or the second retaining part will catch on the intermediate part of the resonator which has a longer circumference. This allows the sound-absorbing unit to restrict the movement of the resonant sound-absorbing material in the first direction by making the circumference of the middle section of the resonator longer than the circumferences of the first and second sections at both ends of the resonator.

[0008] In the sound-absorbing unit described above, the support may include a base portion extending in a first direction and attached to a mounting surface, a first leg portion connecting the base portion and the first holding portion, and a second leg portion connecting the base portion and the second holding portion. In this case, the sound-absorbing unit can be configured such that the first holding portion and the second holding portion, which hold the resonant sound-absorbing body, are connected to each other. This prevents the first holding portion and the second holding portion from separating from each other, and allows the support to hold the resonant sound-absorbing body more securely.

[0009] In the sound-absorbing unit described above, the base portion includes a first base and a second base, the first leg portion includes a first leg body connecting the first base and the first holding portion and a second leg body connecting the second base and the first holding portion, and the second leg portion may include a third leg body connecting the first base and the second holding portion and a fourth leg body connecting the second base and the second holding portion. In this case, the sound-absorbing unit can more stably support the resonant sound absorber by having the first base and the second base as parts that are attached to the mounting surface inside the lumen.

[0010] In the sound-absorbing unit described above, the first base may extend outwards from the connection point with the first and third legs toward the opposite side of the second base, and the second base may extend outwards from the connection point with the second and fourth legs toward the opposite side of the first base. In this case, even if the sound-absorbing unit vibrates due to the rotation of the tires, the first and second bases, which extend outwards from each other, can suppress the shaking of the sound-absorbing unit and support it more stably.

[0011] In the sound-absorbing unit described above, the intermediate portion may protrude more toward the opposite side of the mounting surface than the first and second portions. For example, if the support is deformed, a gap may occur between the first holding portion of the support and the first portion of the resonator, on the mounting surface side. Similarly, a gap may occur between the second holding portion of the support and the second portion of the resonator, on the mounting surface side. Even if such gaps occur, the intermediate portion protruding toward the opposite side of the gap restricts the movement of the resonant sound absorber, allowing the sound-absorbing unit to hold the resonant sound absorber more securely.

[0012] In the above-described sound-absorbing unit, the resonant sound-absorbing body may further include a hollow neck portion that extends outside the resonator and has one end communicating with an opening, and a neck support portion that connects the resonator and the neck portion. In this case, the sound-absorbing unit can adjust the frequency of sound absorbed by the resonant sound-absorbing body by including the neck portion. Furthermore, in the sound-absorbing unit, the neck portion that extends outside the resonator can be supported by the neck support portion relative to the resonator. This ensures that the neck portion is stably supported even when centrifugal force, vibration, etc. are applied due to the rotation of the tire. In this way, deformation of the neck portion that extends outside the resonator can be suppressed in this sound-absorbing unit.

[0013] In the sound-absorbing unit described above, the neck support portion may be plate-shaped and extend along the direction of extension of the neck portion. In this case, the sound-absorbing unit can support the neck portion over a wide area in the direction of extension of the neck portion using the plate-shaped neck support portion.

[0014] In the above sound-absorbing unit, the thickness of the neck support portion may be greater than the thickness of the neck portion or the thickness of the resonator. When the thickness of the neck support portion is greater than the thickness of the neck portion, the sound-absorbing unit can further suppress deformation of the neck portion. Furthermore, when the thickness of the neck support portion is greater than the thickness of the resonator, the sound-absorbing unit can further suppress deformation of the resonator around the neck support portion. In addition, the deformation of the neck portion can be further suppressed by the neck support portion being greater than the thickness of the resonator.

[0015] In the above sound-absorbing unit, the resonator extends in a direction intersecting the extending direction of the neck portion and has a neck connecting wall in part that separates the hollow portion from the space outside the resonator, with an opening provided in the neck connecting wall, and one end of the neck portion is connected to the neck connecting wall, and the neck portion may extend linearly from the connection portion with the neck connecting wall outside the resonator. In this case, the resonant sound absorber can more efficiently introduce air vibrations in the inner cavity of the tire into the resonator via the neck portion.

[0016] In the sound-absorbing unit described above, the neck portion may extend in the first direction. In this case, by extending the neck portion along the direction of extension of the resonator, the neck portion can be made longer while suppressing an increase in the overall size of the sound-absorbing unit. Furthermore, since the resonator and the neck portion extend in the first direction, a wide area (long along the first direction) can be secured for supporting the neck portion by the neck support portion, allowing for more stable support of the neck portion.

[0017] In the sound-absorbing unit described above, the support may support the resonant sound-absorbing body such that the neck portion is located on the mounting surface side. For example, the mounting surface within the cavity to which the sound-absorbing unit is attached may be the inner circumferential surface of the tire tread. In this case, when centrifugal force is applied to the resonant sound-absorbing body as the tire rotates, the centrifugal force generated at the neck portion is not applied to the resonator. Therefore, deformation of the resonator can be suppressed in the sound-absorbing unit.

[0018] In the above-described sound-absorbing unit, the support may support the resonant sound-absorbing body such that the neck portion is further away from the mounting surface than the portion closest to the mounting surface in the resonator. For example, the mounting surface within the lumen to which the sound-absorbing unit is attached may be the inner circumferential surface of the tire tread. In this case, the tread deforms as the tire rotates, and the mounting surface of the sound-absorbing unit may also deform. Even in this case, by using the above configuration, the neck portion of the sound-absorbing unit can be prevented from contacting the mounting surface, and deformation of the neck portion can be further suppressed.

[0019] In the sound-absorbing unit described above, the second holding part may be inserted inward into the neck portion and the other end of the resonator in the first direction, thereby holding the neck portion and the other end of the resonator in the first direction. In this case, the sound-absorbing unit can also hold the neck portion with the support. This further suppresses deformation of the neck portion of the sound-absorbing unit.

[0020] In the sound-absorbing unit described above, one end of the neck portion is connected to the resonator in the region between the first and second holding portions in a first direction, and the other end of the neck portion opposite to the one end extends outside the region between the first and second holding portions via the second holding portion, and the neck support portion may connect the resonator and the neck portion at least outside the region between the first and second holding portions. As a result, the sound-absorbing unit can support the other end of the neck portion with the neck support portion in the portion outside the portion held by the second holding portion (the portion outside the region between the first and second holding portions). Therefore, the deformation of the neck portion of the sound-absorbing unit can be further suppressed.

[0021] In the sound-absorbing unit described above, the outer surface of the first portion may be provided with a first protrusion on the portion opposite to the intermediate portion from the first holding portion in the first direction, or the outer surface of the second portion may be provided with a second protrusion on the portion opposite to the intermediate portion from the second holding portion in the first direction. In this case, the sound-absorbing unit can have the first protrusion restrict the movement of the first portion of the resonator, or the second protrusion can restrict the movement of the second portion of the resonator.

[0022] In the sound-absorbing unit described above, the support may support the resonant sound absorber such that the neck portion extends along the width direction of the tire. For example, the tread of a tire deforms as the tire rotates (as the vehicle on which the tire is installed moves). This deformation tends to be greater in the circumferential direction (direction of rotation) of the tire than in the width direction. For this reason, if the sound-absorbing unit is attached to the inner circumferential surface of the tire tread, the direction in which the neck portion extends will be aligned with the direction in which the tire deforms less. Therefore, even if the tread deforms due to the rotation of the tire, the sound-absorbing unit can suppress deformation of the neck portion in accordance with the deformation of the tread.

[0023] In the above-described sound-absorbing unit, the resonant sound-absorbing material may have a Helmholtz resonance structure that absorbs resonant sounds between 180 Hz and 300 Hz generated within the lumen. In this case, the sound-absorbing unit can absorb resonant sounds generated within the lumen of the tire more efficiently.

[0024] According to this disclosure, a resonant sound absorber can be firmly fixed to a support.

[0025] Figure 1 is a schematic cross-sectional view of a tire to which a sound-absorbing unit according to an embodiment is attached. Figure 2 is a schematic perspective view of the sound-absorbing unit of Figure 1 as seen from the opening side. Figure 3 is a schematic front view of the sound-absorbing unit of Figure 2 as seen from the opening side. Figure 4 is a schematic side view of the sound-absorbing unit of Figure 2. Figure 5 is a schematic rear view of the sound-absorbing unit of Figure 2 as seen from the opposite side of the opening. Figure 6 is a schematic cross-sectional view of the sound-absorbing unit of Figure 1 cut along its longitudinal direction.

[0026] Hereinafter, embodiments of the sound-absorbing unit according to this 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 redundant explanations are omitted. Furthermore, numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively.

[0027] Figure 1 is a schematic cross-sectional view of a tire to which a sound-absorbing unit according to the embodiment is attached. In a tire T, cavity resonance can occur when the air inside the cavity S resonates in response to vibrations when passing over uneven surfaces on the road surface during vehicle travel. The frequency of cavity resonance is approximately 180 Hz to 300 Hz, or approximately 200 Hz to 300 Hz, typically around 250 Hz. This frequency of cavity resonance changes depending on the size of the tire T, etc. The sound-absorbing unit 100 according to this embodiment is attached to the mounting surface Ta inside the cavity S in order to efficiently absorb such low-frequency cavity resonance (for example, approximately 180 Hz to 300 Hz or approximately 200 Hz to 300 Hz). The cavity S of the tire T is an annular space demarcated by the outer circumferential surface Ha of the wheel H on which the tire T is mounted and the inner surface of the tire T. In this embodiment, the mounting surface Ta is the inner circumferential surface (back surface of the tread) of the tread Tb of the tire T. However, the mounting surface Ta is not limited to the inner circumferential surface of the tread Tb. For example, the mounting surface Ta may be the outer circumferential surface Ha of the wheel H. The sound-absorbing unit 100 can be attached to any mounting surface provided in any part of the inner cavity S.

[0028] In this embodiment, four sound-absorbing units 100 are provided within the inner cavity S of the tire T. In this embodiment, the four sound-absorbing units 100 are mounted on the mounting surface Ta at positions offset by 90° from each other in the rotational direction of the tire T. However, the number and mounting positions of the sound-absorbing units 100 are not limited to the configuration shown in Figure 1. Furthermore, the sound-absorbing units 100 may be mounted within the inner cavity S of the tire T in combination with other functional components such as a power generator, sensor device, secondary battery, capacitor, antenna device, transmitter, processor, memory, and circuit, as needed. In that case, it is preferable to mount them in an appropriate arrangement so that the weight inside the tire T is uniform, taking into consideration the weight and number of the functional components to be mounted and the sound-absorbing units 100.

[0029] The sound-absorbing unit 100 will be described with reference to Figures 2 to 6. Figure 2 is a schematic perspective view of the sound-absorbing unit of Figure 1 as seen from the opening side. Figure 3 is a schematic front view of the sound-absorbing unit of Figure 2 as seen from the opening side. Figure 4 is a schematic side view of the sound-absorbing unit of Figure 2. Figure 5 is a schematic rear view of the sound-absorbing unit of Figure 2 as seen from the opposite side of the opening. Figure 6 is a cross-sectional view of the sound-absorbing unit of Figure 1 cut along its longitudinal direction.

[0030] As shown in Figures 2 to 6, the sound absorption unit 100 comprises a resonant sound absorber 1 and a support 5. The resonant sound absorber 1 has a Helmholtz resonance structure that absorbs resonant sounds between 180 Hz and 300 Hz generated in the lumen S. The resonant sound absorber 1 absorbs the resonant sound (sound) in the lumen S. The support 5 is attached to the mounting surface Ta of the tire T. The support 5 supports the resonant sound absorber 1 with respect to the mounting surface Ta.

[0031] First, the details of the resonant sound absorber 1 will be described. The resonant sound absorber 1 comprises a resonator 10, a neck portion 20, and a neck support portion 30. A hollow portion R (see Figure 6) is provided inside the resonator 10. The resonator 10 constitutes a wall portion that defines the hollow portion R. The resonator 10 has an opening 10a (see Figure 6) that opens the hollow portion R to the outside. The resonator 10 is configured to be elongated in the direction along the first axis L1. In this embodiment, as an example, the sound absorbing unit 100 is attached to the mounting surface Ta of the tire T by the support 5 such that the first axis L1 is parallel (approximately parallel) to the rotation axis of the tire T.

[0032] Here, the direction along the first axis L1 is defined as the first direction D1. The first direction D1 is also the direction along the rotation axis of the tire T. The direction perpendicular to the first direction D1, and in which the mounting surface Ta of the tire T and the resonant sound absorber 1 face each other, is defined as the second direction D2 (see Figures 3 and 4). The second direction D2 is also the direction in which the support 5 lifts the resonant sound absorber 1 relative to the mounting surface Ta of the tire T. The second direction D2 is also the direction along the radial direction of the tire T. The direction along the first direction D1 and the second direction D2 is defined as the third direction D3.

[0033] In this embodiment, the resonator 10 is composed of three parts arranged along a first direction D1. The resonator 10 comprises a first part 11, a second part 12, and an intermediate part 13. The first part 11 is the part of the resonator 10 at one end in the first direction D1. The second part 12 is the part of the resonator 10 at the other end opposite to the first end in the first direction D1. The intermediate part 13 is the part of the resonator 10 between the first part 11 and the second part 12 in the first direction D1. The first part 11, the intermediate part 13, and the second part 12 are arranged in this order in the first direction D1. The first part 11 is located at one end of the resonator 10 in the first direction D1. The second part 12 is located at the other end of the resonator 10 in the first direction D1.

[0034] The first part 11, the second part 12, and the intermediate part 13 define the hollow portion R. The first part 11, the second part 12, and the intermediate part 13 constitute the wall portion that defines the hollow portion R. The intermediate part 13 has a substantially cylindrical shape with the end to which the first part 11 is connected and the end to which the second part 12 is connected open in the first direction D1. The first part 11 has a shape with the end to which the intermediate part 13 is connected open in the first direction D1, and the end opposite to the end connected to the intermediate part 13 closed. The second part 12 has a shape with the end to which the intermediate part 13 is connected open in the first direction D1, and the end opposite to the end connected to the intermediate part 13 closed.

[0035] In the intermediate portion 13, the perimeter of the outer surface 13s of the intermediate portion 13 around the first axis L1 is longer than the perimeter of the outer surface 11s of the first portion 11 and the perimeter of the outer surface 12s of the second portion 12 around the first axis L1. The perimeter of the outer surface 13s of the intermediate portion 13 is defined as the perimeter of the longest portion of the outer surface 13s of the intermediate portion 13. In other words, for example, the intermediate portion 13 has a larger outer shape than the first portion 11 and the second portion 12 in at least one of the second direction D2 and the third direction D3. The intermediate portion 13 has a portion that protrudes outward more than the first portion 11 and the second portion 12 in at least one of the second direction D2 and the third direction D3.

[0036] In this embodiment, the intermediate portion 13 protrudes more toward the opposite side of the mounting surface Ta of the tire T than the first portion 11 and the second portion 12. In other words, the intermediate portion 13 protrudes more toward the rotation axis side of the tire T than the portions of the first portion 11 and the second portion 12 toward the rotation axis side of the tire T.

[0037] The intermediate portion 13 has a recessed portion 13a. The recessed portion 13a is provided on the surface of the intermediate portion 13 facing the mounting surface Ta. Furthermore, the recessed portion 13a is provided in the portion of the intermediate portion 13 adjacent to the second portion 12 in the first direction D1. Thus, the intermediate portion 13 has a first intermediate portion 13b, which is the portion without the recessed portion 13a, and a second intermediate portion 13c, which is the portion with the recessed portion 13a. The recessed portion 13a of the intermediate portion 13 corresponds to the portion of the second intermediate portion 13c on the side facing the mounting surface Ta of the tire T.

[0038] The first intermediate portion 13b and the second intermediate portion 13c are adjacent to each other in the first direction D1. The first intermediate portion 13b is continuous with the first portion 11, and the second intermediate portion 13c is continuous with the second portion 12. The perimeter of the outer surface of the first intermediate portion 13b around the first axis L1 is longer than the perimeter of the outer surface of the second intermediate portion 13c around the first axis L1. However, in the second intermediate portion 13c, the perimeter around the first axis L1 is longer than the perimeter around the first axis L1 in the second portion 12.

[0039] Because a recess 13a is provided in the intermediate portion 13, a step is created at the connection point between the first intermediate portion 13b and the second intermediate portion 13c. The first intermediate portion 13b has a stepped wall (neck connection wall) 13d facing the recess 13a side of the intermediate portion 13. The stepped wall 13d extends in a direction intersecting the first direction D1. In this embodiment, the stepped wall 13d may, for example, extend in a direction perpendicular to the first direction D1.

[0040] Thus, the resonator 10 extends in a direction intersecting the first direction D1 and has a stepped wall 13d in part that separates the hollow portion R from the external space of the resonator 10. An opening 10a is provided in the stepped wall 13d.

[0041] As shown in Figure 4, the portion of the first intermediate portion 13b closest to the mounting surface Ta of the tire T and the portion of the first portion 11 closest to the mounting surface Ta of the tire T are in approximately the same position in the second direction D2. The portion of the second intermediate portion 13c closest to the mounting surface Ta of the tire T and the portion of the second portion 12 closest to the mounting surface Ta of the tire T are in approximately the same position in the second direction D2. The portion of the second portion 12 and the second intermediate portion 13c closer to the mounting surface Ta of the tire T is provided with a space facing the stepped wall 13d in the first direction D1 (a space where the neck portion 20 and the neck support portion 30 are provided). Thus, the positions of the first portion 11 and the second portion 12 in the second direction D2 connected to the intermediate portion 13 are different.

[0042] As shown in Figure 5, when viewed along the first direction D1, the outer shape of the first portion 11 is substantially elliptical. Therefore, rotation of the first portion 11 around the first axis L1 within the first holding portion 51 can be suppressed. As shown in Figure 3, when viewed along the first direction D1, the outer shape of the second portion 12 is substantially D-shaped. In other words, when viewed along the first direction D1, the outer shape of the second portion 12 has a substantially flat portion and an arc-shaped portion. In this embodiment, the portion of the second portion 12 facing the mounting surface Ta of the tire T is a substantially flat surface 12a. This flat surface 12a extends generally along the first direction D1 and the third direction D3. Therefore, rotation of the second portion 12 around the first axis L1 within the second holding portion 52 can be suppressed.

[0043] The neck portion 20 is a hollow member having a hollow portion 20a (see FIG. 6) inside. The neck portion 20 extends outside the resonator 10. The neck portion 20 has a base end portion 20b which is one end portion in the extending direction, and a tip end portion 20c which is the other end portion opposite to the base end portion 20b. The base end portion 20b and the tip end portion 20c are open ends that open the hollow portion 20a to the outside, respectively. The base end portion 20b of the neck portion 20 is communicated with the opening 10a of the resonator 10. That is, the base end portion 20b of the neck portion 20 is connected to the stepped wall 13d of the resonator 10. The hollow portion R of the resonator 10 communicates with the external space (inside the inner cavity S) of the resonance absorber 1 through the opening 10a of the resonator 10, the hollow portion 20a of the neck portion 20, and the tip end portion 20c of the neck portion 20.

[0044] In the present embodiment, the neck portion 20 extends in the first direction D1. The neck portion 20 linearly extends in the first direction D1 from the connection portion with the stepped wall 13d outside the resonator 10. The neck portion 20 extends in the first direction D1 at a position closer to the mounting surface Ta of the tire T than the second portion 12 and the second intermediate portion 13c. In the first direction D1, the tip end portion 20c of the neck portion 20 protrudes outward from the resonator 10 (the second portion 12) as an example in the present embodiment.

[0045] The resonance absorber 1 can lower the resonance frequency in the resonator 10 and the neck portion 20 by increasing the length of the neck portion 20. That is, the resonance absorber 1 can reduce the resonance sound in the low frequency range by increasing the length of the neck portion 20. In the present embodiment, the neck portion 20 is a circular tube as an example. For example, the cross-sectional shape of the hollow portion 20a of the neck portion 20 may be the same size as or larger than the opening 10a of the resonator 10. However, the shape of the neck portion 20 (the cross-sectional shape of the hollow portion 20a) and the like are not particularly limited.

[0046] The neck support portion 30 connects the outer surface 10s of the resonator 10 and the neck portion 20. In the present embodiment, the neck support portion 30 has a plate shape extending along the extending direction of the neck portion 20. The neck support portion 30 connects the outer surfaces of the second portion 12 and the second intermediate portion 13c among the outer surfaces 10s of the resonator 10 and the neck portion 20. In the present embodiment, the neck support portion 30 is provided over the entire range where the neck portion 20, the second portion 12, and the second intermediate portion 13c exist in parallel in the first direction D1. In other words, the neck support portion 30 is provided over the entire range where the neck portion 20 faces the second portion 12 and the second intermediate portion 13c in the second direction D2.

[0047] In the present embodiment, a case where only one neck support portion 30 is provided will be described as an example. However, the present invention is not limited to this, and a plurality of neck support portions 30 may be arranged side by side along the extending direction of the neck portion 20. Further, the neck support portion 30 is not limited to having a plate shape. The neck support portion 30 only needs to be able to connect the outer surface 10s of the resonator 10 and the neck portion 20.

[0048] The length of the resonance absorber 1 in the first direction D1 is, for example, about 40 mm to 90 mm. The length of the resonance absorber 1 in the second direction D2 is, for example, about 20 mm to 50 mm. The length of the resonance absorber 1 in the third direction D3 is, for example, about 15 mm to 40 mm. The length of the neck portion 20 (the length in the first direction D1) may be, for example, about half of the length of the resonance absorber 1 in the first direction D1. The diameter of the neck portion 20 may be, for example, about 3 mm to 6 mm. The thickness of the resonance absorber 1 may be, for example, about 0.3 mm to 0.6 mm. Note that the thickness of the neck support portion 30 may be thicker than the thickness of the resonator 10 or the neck portion 20. For example, the thickness of the neck support portion 30 may be about twice the thickness of the resonator 10 and the neck portion 20. The resonator 10, the neck portion 20, and the neck support portion 30 may be integrally formed.

[0049] The materials of the resonator 10, the neck portion 20, and the neck support portion 30 may be the same or different from each other. The material of the resonant sound absorber 1 may be, for example, a thermoplastic such as polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polycarbonate (PC), polyacetal (POM), or polyphenylene sulfide (PPS); or a thermoplastic elastomer such as olefin-based (TPO), dynamically cross-linked (TPV), styrene-based (TPS), polyurethane-based (TPU), or polyester-based (TPEE); or a vulcanized rubber such as natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), or chloroprene rubber (CR).

[0050] Next, the details of the support 5 will be described. The support 5 supports the resonant sound absorber 1 while being spaced apart from the mounting surface Ta. The support 5 supports the resonant sound absorber 1 such that the neck portion 20 is located on the mounting surface Ta side of the tire T. In other words, the support 5 supports the resonant sound absorber 1 such that the neck portion 20 is located on the mounting surface Ta side of the second portion 12 and second intermediate portion 13c of the resonator 10.

[0051] The support 5 comprises a first holding portion 51, a second holding portion 52, a base portion 60, a first leg portion 71, and a second leg portion 72. The first holding portion 51 and the second holding portion 52 are provided at a predetermined distance from each other in the first direction D1. The first holding portion 51 and the second holding portion 52 each hold both ends of the resonator 10 in the first direction D1 (longitudinal direction).

[0052] As shown in Figure 5, the first retaining portion 51 has a first insertion space 51a on its inside. The first retaining portion 51 has a shape that surrounds the first insertion space 51a. The first retaining portion 51 extends in the circumferential direction centered on the first axis L1 and surrounds the first insertion space 51a. In this embodiment, the first retaining portion 51 has an annular shape that surrounds the first insertion space 51a. However, the first retaining portion 51 is not limited to surrounding the first insertion space 51a over its entire circumference in the circumferential direction centered on the first axis L1. For example, the first retaining portion 51 may have a shape in which a part of the annular shape is cut out.

[0053] A stepped portion provided at one end of the resonator 10 in the first direction D1 is inserted into the inside of the first holding portion 51 (first insertion space 51a). Here, the one end of the resonator 10 in the first direction D1 is the end on which the first portion 11 of the resonator 10 is provided. The stepped portion provided at one end of the resonator 10 in the first direction D1 is the step formed by the intermediate portion 13 and the first portion 11 of the resonator 10. Here, the first portion 11 of the stepped portion formed by the intermediate portion 13 and the first portion 11 is inserted into the inside of the first holding portion 51. The first holding portion 51 holds the one end (first portion 11) of the resonator 10 that has been inserted inside.

[0054] As shown in Figure 3, the second retaining portion 52 has a second insertion space 52a on its inside. The second retaining portion 52 has a shape that surrounds the second insertion space 52a. The second retaining portion 52 extends in the circumferential direction centered on the first axis L1 and surrounds the second insertion space 52a. In this embodiment, the second retaining portion 52 has an annular shape that surrounds the second insertion space 52a. However, the second retaining portion 52 is not limited to surrounding the second insertion space 52a over its entire circumference in the circumferential direction centered on the first axis L1. For example, the second retaining portion 52 may have a shape in which a part of the annular shape is cut out.

[0055] A stepped portion provided at the other end of the resonator 10 opposite to one end in the first direction D1 is inserted into the inside of the second holding portion 52 (second insertion space 52a). Here, the other end of the resonator 10 in the first direction D1 is the end of the resonator 10 on the side where the second portion 12 is provided. The stepped portion provided at the other end of the resonator 10 in the first direction D1 is the step formed by the intermediate portion 13 and the second portion 12 of the resonator 10. Here, the second portion 12 of the stepped portion formed by the intermediate portion 13 and the second portion 12 is inserted into the inside of the second holding portion 52. The second holding portion 52 holds the other end of the resonator 10 (second portion 12) that has been inserted inside.

[0056] On the side of the second retaining portion 52 facing the mounting surface Ta of the tire T, the surface facing the second insertion space 52a (the inner circumferential surface of the second retaining portion 52) is a substantially flat surface 52b. The flat surface 52b of the second retaining portion 52 faces the flat surface 12a of the second portion 12 inserted into the second insertion space 52a.

[0057] Furthermore, a recess 52c is provided on the flat surface 52b of the second holding portion 52. The neck portion 20 and the neck support portion 30 can be inserted into the recess 52c. The portion of the second insertion space 52a into which the second portion 12 is inserted and the space inside the recess 52c are in communication with each other. The second holding portion 52 holds the second portion 12 (the other end of the resonator 10), the neck portion 20, and the neck support portion 30 by inserting them into the inside (second insertion space 52a).

[0058] The base portion 60 extends in a first direction D1. The base portion 60 is attached to the mounting surface Ta of the tire T. The first leg portion 71 connects the base portion 60 and the first holding portion 51. The second leg portion 72 connects the base portion 60 and the second holding portion 52. In this embodiment, the first leg portion 71 and the second leg portion 72 are connected to both ends of the base portion 60 in the first direction D1, respectively.

[0059] More specifically, the base portion 60 is composed of a first base 61 and a second base 62, each extending in a first direction D1. The first base 61 and the second base 62 are attached to the mounting surface Ta of the tire T by, for example, double-sided tape with adhesive surfaces on both sides, adhesive, welding, etc.

[0060] For example, a sealant layer may be provided on the mounting surface Ta of the tire T. This sealant layer may have a function to seal holes in the tire T, for example, to prevent punctures. In this case, the first base 61 and the second base 62 are attached to the sealant layer provided on the mounting surface Ta. That is, the first base 61, etc., are attached to the mounting surface Ta via the sealant layer. The first base 61, etc., are attached to the sealant layer by, for example, an adhesive. Alternatively, the first base 61, etc., may be placed on the sealant layer when the sealant layer is curing, and adhere to the sealant layer as the sealant layer hardens.

[0061] Thus, in this specification, attaching the first base 61 etc. to the mounting surface Ta includes both attaching the first base 61 etc. directly to the mounting surface Ta and attaching the first base 61 etc. to the mounting surface Ta via a member such as a sealant layer.

[0062] As shown in Figure 5, the first leg portion 71 is composed of a first leg body 71a and a second leg body 71b. The first leg body 71a connects the first base 61 and the first holding portion 51. The second leg body 71b connects the second base 62 and the first holding portion 51. The distance between the first leg body 71a and the second leg body 71b increases as they move from the second holding portion 52 toward the base portion 60 (the distance in the third direction D3). The first leg body 71a and the second leg body 71b are connected to the portion of the first holding portion 51 facing the mounting surface Ta side of the tire T, with a predetermined distance between them.

[0063] As shown in Figure 3, the second leg portion 72 is composed of a third leg body 72a and a fourth leg body 72b. The third leg body 72a connects the first base 61 and the second holding portion 52. The fourth leg body 72b connects the second base 62 and the second holding portion 52. The distance between the third leg body 72a and the fourth leg body 72b increases as they move from the second holding portion 52 toward the base portion 60 (the distance in the third direction D3). The third leg body 72a and the fourth leg body 72b are connected to the surfaces of the second holding portion 52 facing the mounting surface Ta of the tire T, with a predetermined distance between them. In this embodiment, the third leg body 72a and the fourth leg body 72b are connected to the outer circumferential surface of the portion of the second holding portion 52 where the flat surface 52b is formed. The third leg portion 72a and the fourth leg portion 72b are connected to the second holding portion 52 such that they sandwich the recess 52c of the second holding portion 52 between them.

[0064] The first base 61 extends outwards from the connection point between the first leg body 71a and the third leg body 72a, toward the opposite side of the second base 62. The second base 62 extends outwards from the connection point between the second leg body 71b and the fourth leg body 72b, toward the opposite side of the first base 61.

[0065] The support 5 supports the resonant sound absorber 1 such that the resonator 10 (neck portion 20) extends along the width direction of the tire T. In the second direction D2, the support 5 supports the resonant sound absorber 1 such that it is spaced, for example, 5 mm to 20 mm away from the mounting surface Ta of the tire T. The support 5 supports the resonant sound absorber 1 such that the neck portion 20 is further away from the mounting surface Ta than the portion of the resonator 10 that is closest to the mounting surface Ta of the tire T. In other words, the support 5 holds the resonant sound absorber 1 such that the distance between the neck portion 20 and the mounting surface Ta is greater than the distance between the first portion 11 and the intermediate portion 13 of the resonator 10 and the mounting surface Ta.

[0066] As shown in Figure 4, the first holding part 51 holds the first part 11 of the resonator 10, and the second holding part 52 holds the second part 12 of the resonator 10. In other words, the intermediate part 13 of the resonator 10 is located between the first holding part 51 and the second holding part 52. As described above, the base end 20b of the neck part 20 is connected to the stepped wall 13d of the intermediate part 13. In other words, the base end 20b (one end) of the neck part 20 is connected to the resonator 10 in the region between the first holding part 51 and the second holding part 52 in the first direction D1. Thus, the base end 20b of the neck part 20 is connected to the resonator 10 in the intermediate part 13.

[0067] The neck portion 20 is inserted inside the second retaining portion 52 and is held by the second retaining portion 52. In other words, the tip portion 20c of the neck portion 20 extends through the second retaining portion 52 to the outside of the region between the first retaining portion 51 and the second retaining portion 52. The neck support portion 30 connects the outer surface 10s of the resonator 10 to the neck portion 20, at least outside the region between the first retaining portion 51 and the second retaining portion 52. In this embodiment, the neck support portion 30 extends across the second retaining portion 52 in the first direction D1. The neck support portion 30 connects the outer surface 10s of the resonator 10 to the neck portion 20 in the region between the first retaining portion 51 and the second retaining portion 52, and in the region outside thereof.

[0068] As shown in Figures 4 and 5, a first protrusion 11t is provided on the outer surface 11s of the first portion 11 of the resonator 10. There may be one first protrusion 11t or multiple first protrusions 11t. In this embodiment, there are two first protrusions 11t. The first protrusions 11t are provided on the portion opposite to the intermediate portion 13 from the first retaining portion 51 in the first direction D1. That is, the first retaining portion 51 is located between the intermediate portion 13 and the first protrusions 11t in the first direction D1. The first protrusions 11t function as stoppers that restrict the movement of the first portion 11 of the resonator 10 by catching on the first retaining portion 51.

[0069] As shown in Figures 3 and 4, a second protrusion 12t is provided on the outer surface 12s of the second portion 12 of the resonator 10. There may be one second protrusion 12t or multiple second protrusions 12t. In this embodiment, three second protrusions 12t are provided. In the first direction D1, the second protrusions 12t are provided on the portion opposite to the intermediate portion 13 from the second retaining portion 52. That is, in the first direction D1, the second retaining portion 52 is located between the intermediate portion 13 and the second protrusions 12t. The second protrusions 12t function as stoppers that restrict the movement of the second portion 12 of the resonator 10 by catching on the second retaining portion 52. Note that a configuration in which only one of the first protrusions 11t and the second protrusions 12t is provided is also possible.

[0070] The first holding portion 51, the second holding portion 52, the base portion 60, the first leg portion 71, and the second leg portion 72 may be constructed as a single unit. The materials of the first holding portion 51, the second holding portion 52, the base portion 60, the first leg portion 71, and the second leg portion 72 may be the same or different from each other.

[0071] The support 5 is elastically deformable. The material of the support 5 may be, for example, a dynamically crosslinked thermoplastic elastomer (TPV), or a vulcanized rubber such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), chloroprene rubber (CR), or isoprene rubber (IR). By using these materials, a support 5 can be obtained that is excellent in elasticity, heat resistance, and flexibility, and is suitable as a support member in the lumen S of the tire T.

[0072] However, the material of the support 5 is not limited to these. In addition to these, the material of the support 5 may be a thermoplastic elastomer other than a dynamically crosslinked thermoplastic elastomer (TPV) (for example, styrene-based (TPS), polyolefin-based (TPO), polyurethane-based (TPU), polyester-based (TPEE), polyester-based (TPC), etc.). Furthermore, the material of the support 5 may be various foam materials (for example, foamed rubber, foamed urethane, etc.).

[0073] Next, the configuration in which the resonant sound absorber 1 is held by the support body 5 will be described. As the tire T to which the sound-absorbing unit 100 is attached rotates, the sound-absorbing unit 100 is subjected to centrifugal force, strain due to deformation of the tire tread Tb, vibration, etc. In this embodiment, the first part 11 of the resonator 10 is inserted into the first holding part 51 of the support body 5, and the second part 12 of the resonator 10 is inserted into the second holding part 52 of the support body 5. The first holding part 51 of the support body 5 surrounds and holds the first part 11 of the resonator 10. The second holding part 52 of the support body 5 surrounds and holds the second part 12 of the resonator 10. Therefore, the support body 5 can hold the resonant sound absorber 1 so that it does not move in a direction other than the first direction D1.

[0074] Furthermore, the intermediate portion 13 of the resonator 10 has a longer circumference than the first portion 11 and the second portion 12. Therefore, even if the resonant sound absorber 1 tries to move in the first direction D1, the intermediate portion 13 catches on the first holding portion 51 or the second holding portion 52. As a result, the support 5 can restrict the movement of the resonant sound absorber 1 in the first direction D1. In addition, the movement of the resonant sound absorber 1 in the first direction D1 can also be restricted by the first protrusion 11t provided on the first portion 11 of the resonator 10 and the second protrusion 12t provided on the second portion 12.

[0075] The first holding portion 51 is better positioned to hold the portion of the first part 11 that is closer to the intermediate portion 13. In other words, it is better that the length of the first direction D1 of the outer surface 11s of the portion of the first part 11 where the first protrusion 11t is provided is longer. This allows the first holding portion 51 to hold the first part 11 of the resonator 10 more securely. Similarly, on the second part 12 side, it is better that the length of the first direction D1 of the outer surface 12s of the portion where the second protrusion 12t is provided is longer. This allows the second holding portion 52 to hold the second part 12 of the resonator 10 more securely.

[0076] The circumferential lengths of the inner surfaces of the first holding portion 51 and the second holding portion 52 are shorter than the circumferential length of the outer surface 13s of the intermediate portion 13 around the first axis L1. The circumferential lengths of the inner surfaces of the first holding portion 51 and the second holding portion 52 can be made shorter than the circumferential length of the outer surface 13s of the intermediate portion 13 even when elastically deformed. As a result, the resonator 10 can be held even if the first holding portion 51 and the second holding portion 52 stretch due to elastic deformation.

[0077] Next, a configuration for attaching the resonant sound absorber 1 to the support 5 will be described. The support 5 is elastically deformable. Therefore, when attaching the resonant sound absorber 1 to the support 5, the resonant sound absorber 1 can be attached by elastically deforming the support 5. For example, first, the first part 11 of the resonator 10 is inserted into the first holding part 51 of the support 5. Then, while elastically deforming the support 5, the second part 12 and the neck part 20 of the resonator 10 may be inserted into the second holding part 52 of the support 5. In this case, for example, as shown in Figure 4, the end face 12b of the second part 12 in the first direction D1 is preferably inclined with respect to the second direction D2 which is perpendicular to the first direction D1. The end face 12b is preferably inclined such that the edge opposite to the neck part 20 side is closer to the second intermediate part 13c side in the second direction D2 than the edge on the neck part 20 side. In this case, when fitting the second portion 12 into the second holding portion 52, the end of the second portion 12 can be prevented from getting caught, and the second portion 12 can be easily inserted into the second holding portion 52. However, the method of attaching the resonant sound absorber 1 to the support 5 is not particularly limited. The resonant sound absorber 1 can be attached to the support 5 using an appropriate method.

[0078] As described above, in the sound-absorbing unit 100, the stepped portions (first portion 11 and second portion 12) at both ends in the longitudinal direction of the resonant sound-absorbing body 1 are inserted inside the first holding portion 51 and the second holding portion 52 of the support body 5. The first holding portion 51 and the second holding portion 52 surround both ends of the resonator 10 around the first axis L1. Therefore, even if the resonant sound-absorbing body 1 attempts to move in a direction intersecting the first direction D1 (the direction intersecting the first axis L1) relative to the support body 5, the sound-absorbing unit 100 can hold the resonant sound-absorbing body 1 with the first holding portion 51 and the second holding portion 52. Furthermore, because both ends of the resonator 10 are stepped portions, if the resonant sound-absorbing body 1 attempts to move along the first direction D1, the first holding portion 51 or the second holding portion 52 of the support body 5 will catch on the step of the resonator 10. Therefore, in the sound-absorbing unit 100, the movement of the resonant sound-absorbing body 1 in the first direction D1 can be restricted by the first holding portion 51 and the second holding portion 52 of the support body 5. In this way, the resonant sound-absorbing body 1 can be firmly fixed to the support body 5 in the sound-absorbing unit 100.

[0079] The resonator 10 has a first portion 11, a second portion 12, and an intermediate portion 13 provided between the first portion 11 and the second portion 12. The circumference of the outer surface 13s of the intermediate portion 13 around the first axis L1 is longer than the circumference of the outer surfaces of the first portion 11 and the second portion 12, respectively. A stepped portion provided at one end of the resonator 10 in the first direction D1 is formed by the intermediate portion 13 and the first portion 11. A stepped portion provided at the other end of the resonator 10 in the first direction D1 is formed by the intermediate portion 13 and the second portion 12. The first retaining portion 51 holds the first portion 11 of the resonator 10 by inserting the first portion 11 into it. The second retaining portion 52 holds the second portion 12 of the resonator 10 by inserting the second portion 12 into it. For example, if the resonant sound absorber 1 attempts to move along the first direction D1, the longer-circumferential intermediate portion 13 of the resonator 10 will catch on the first holding portion 51 or the second holding portion 52. As a result, the sound absorption unit 100 can restrict the movement of the resonant sound absorber 1 in the first direction D1 by making the circumference of the intermediate portion 13 of the resonator 10 longer than the circumferences of the outer surfaces of the first portion 11 and the second portion 12 of the resonator 10, respectively.

[0080] The support 5 has a base portion 60, a first leg portion 71 connecting the base portion 60 and the first holding portion 51, and a second leg portion 72 connecting the base portion 60 and the second holding portion 52. In this case, the sound-absorbing unit 100 can have the first holding portion 51 and the second holding portion 52 of the support 5 that holds the resonant sound-absorbing body 1 connected to each other. As a result, the sound-absorbing unit 100 can suppress the separation of the first holding portion 51 and the second holding portion 52 from each other, and the support 5 can hold the resonant sound-absorbing body 1 more securely.

[0081] The base portion 60 includes a first base 61 and a second base 62. The first leg portion 71 includes a first leg body 71a connecting the first base 61 and the first holding portion 51, and a second leg body 71b connecting the second base 62 and the first holding portion 51. The second leg portion 72 includes a third leg body 72a connecting the first base 61 and the second holding portion 52, and a fourth leg body 72b connecting the second base 62 and the second holding portion 52. In this case, the sound-absorbing unit 100 can support the resonant sound absorber 1 more stably by having the first base 61 and the second base 62 as parts that are attached to the mounting surface Ta of the tire T.

[0082] In the support 5, the first base 61 protrudes from the connection portion with the first leg 71a and the third leg 72a toward the opposite side to the second base 62. The second base 62 protrudes from the connection portion with the second leg 71b and the fourth leg 72b toward the opposite side to the first base 61. In this case, even if the sound-absorbing unit 100 vibrates due to the rotation of the tire T, the first base 61 and the second base 62, which protrude outward from each other, can suppress the shaking of the sound-absorbing unit 100 and support the sound-absorbing unit 100 more stably.

[0083] The intermediate portion 13 of the resonator 10 protrudes more than the first portion 11 and the second portion 12 toward the opposite side of the mounting surface Ta of the tire T. For example, if the support 5 deforms, a gap may occur between the first holding portion 51 of the support 5 and the first portion 11 of the resonator 10 on the side of the mounting surface Ta of the tire T. Similarly, a gap may occur between the second holding portion 52 of the support 5 and the second portion 12 of the resonator 10 on the side of the mounting surface Ta of the tire T. Even if such gaps occur, the intermediate portion 13 protruding toward the opposite side of the gap restricts the movement of the resonant sound absorber 1, allowing the resonant sound absorber 1 to be held more securely in the sound absorption unit 100.

[0084] The resonant sound absorber 1 comprises a neck portion 20 and a neck support portion 30 that connects the neck portion 20 to the outer surface 10s of the resonator 10. In this case, the sound absorption unit 100 can adjust the frequency of sound absorbed by the resonant sound absorber 1 by having the neck portion 20 in the resonant sound absorber 1. Furthermore, in the sound absorption unit 100, the neck portion 20 that extends outside the resonator 10 can be supported by the neck support portion 30 relative to the resonator 10. As a result, the neck portion 20 is stably supported even when centrifugal force, vibration, etc. are applied due to the rotation of the tire T. In this way, the deformation of the neck portion 20 that extends outside the resonator 10 can be suppressed in this sound absorption unit 100.

[0085] The neck support portion 30 is plate-shaped and extends along the extending direction of the neck portion 20. In this case, the sound-absorbing unit 100 can support the neck portion 20 over a wide area in the extending direction of the neck portion 20 using the plate-shaped neck support portion 30.

[0086] The thickness of the neck support portion 30 may be greater than the thickness of the neck portion 20 or the thickness of the resonator 10. If the thickness of the neck support portion 30 is greater than the thickness of the neck portion 20, the sound-absorbing unit 100 can further suppress deformation of the neck portion 20. Also, if the thickness of the neck support portion 30 is greater than the thickness of the resonator 10, the sound-absorbing unit 100 can further suppress deformation of the resonator 10 around the neck support portion 30. Furthermore, because the thickness of the neck support portion 30 is greater than the thickness of the resonator 10, deformation of the neck portion 20 can also be further suppressed.

[0087] The resonator 10 has a stepped wall 13d in part that extends in a direction intersecting the extending direction of the neck portion 20. The neck portion 20 is connected to the stepped wall 13d and extends linearly from the connection portion with the stepped wall 13d. In this case, the resonant sound absorber 1 can more efficiently introduce air vibrations in the cavity S of the tire T into the resonator 10 via the neck portion 20.

[0088] The resonator 10 is configured to be long in the first direction D1. The neck portion 20 extends in the first direction D1. In this case, the sound-absorbing unit 100 can lengthen the neck portion 20 while suppressing an increase in the overall size of the sound-absorbing unit 100 by extending the neck portion 20 along the direction of extension of the resonator 10. Furthermore, because the resonator 10 and the neck portion 20 extend in the first direction D1, a wide area (long along the first direction D1) can be secured for supporting the neck portion 20 by the neck support portion 30, allowing the neck portion 20 to be supported more stably.

[0089] The support 5 supports the resonant sound absorber 1 such that the neck portion 20 is located on the mounting surface Ta side of the tire T. For example, the mounting surface Ta in the inner cavity S to which the sound absorbing unit 100 is attached may be the inner circumferential surface of the tread Tb of the tire T. In this case, when centrifugal force is applied to the resonant sound absorber 1 as the tire T rotates, the centrifugal force generated in the neck portion 20 is not applied to the resonator 10. Therefore, the sound absorbing unit 100 can suppress deformation of the resonator 10.

[0090] The support 5 supports the resonant sound absorber 1 such that the neck portion 20 is further away from the mounting surface Ta of the tire T than the portion of the neck portion 20 that is closest to the mounting surface Ta of the tire T in the resonator 10. For example, the mounting surface Ta in the inner cavity S to which the sound-absorbing unit 100 is attached may be the inner circumferential surface of the tread Tb of the tire T. In this case, as the tire T rotates, the tread Tb deforms, and the mounting surface Ta to which the sound-absorbing unit 100 is attached may also deform. Even in this case, by having the above configuration, the sound-absorbing unit 100 can suppress contact between the neck portion 20 and the mounting surface Ta of the tire T, and can further suppress deformation of the neck portion 20.

[0091] The second portion 12 and the neck portion 20 of the resonator 10 are inserted inside the second holding portion 52 of the support 5. The second holding portion 52 holds the second portion 12 and the neck portion 20. In this case, the sound-absorbing unit 100 can also hold the neck portion 20 with the support 5. As a result, the sound-absorbing unit 100 can further suppress deformation of the neck portion 20.

[0092] The neck support portion 30 connects the neck portion 20 to the outer surface 10s (outer surface 12s of the second portion 12) of the resonator 10, at least outside the region between the first holding portion 51 and the second holding portion 52 of the support 5. As a result, the sound-absorbing unit 100 can support the portion of the neck portion 20 on the tip portion 20c side with the neck support portion 30 in the portion outside the portion held by the second holding portion 52 (the portion outside the region between the first holding portion 51 and the second holding portion 52). Therefore, the sound-absorbing unit 100 can further suppress deformation of the neck portion 20.

[0093] A first protrusion 11t is provided on the outer surface 11s of the first portion 11 of the resonator 10. A second protrusion 12t is provided on the outer surface 12s of the second portion 12 of the resonator 10. In this case, in the sound-absorbing unit 100, the first protrusion 11t can restrict the movement of the first portion 11 of the resonator 10. Also, in the sound-absorbing unit 100, the second protrusion 12t can restrict the movement of the second portion 12 of the resonator 10.

[0094] The support 5 supports the resonant sound absorber 1 such that the neck portion 20 extends along the width direction of the tire T. For example, the tread Tb of the tire T deforms as the tire T rotates (as the vehicle on which the tire T is installed moves). This deformation tends to be greater in the circumferential direction (rotation direction) of the tire T than in the width direction. For this reason, if the sound absorbing unit 100 is attached to the inner circumferential surface of the tread Tb of the tire T, the extending direction of the neck portion 20 will be aligned with the direction in which the tire T deforms less. Therefore, with the sound absorbing unit 100, even if the tread Tb deforms due to the rotation of the tire T, deformation of the neck portion 20 in accordance with the deformation of the tread Tb can be suppressed.

[0095] The resonant sound absorber 1 has a Helmholtz resonance structure that absorbs resonant sounds between 180 Hz and 300 Hz generated within the lumen S. In this case, the sound absorption unit 100 can absorb resonant sounds generated within the lumen S of the tire T more efficiently.

[0096] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The resonator 10 is not limited to a configuration comprising the first portion 11, the second portion 12, and the intermediate portion 13 described above. At least, steps should be provided at both ends of the resonator 10. For example, the intermediate portion 13 may include a portion whose circumference around the first axis L1 is shorter than that of the first portion 11 and the second portion 12. The shape of the resonator 10 is not limited to the shape described above.

[0097] The position where the neck portion 20 is provided is not limited to the part of the resonator 10 on the side of the mounting surface Ta of the tire T. For example, the neck portion may be provided on the part of the resonator opposite to the mounting surface Ta of the tire T. In other words, the resonator may be located between the neck portion and the mounting surface Ta of the tire T (or a part of the resonator may be located between the neck portion and the mounting surface Ta of the tire T).

[0098] The gist of this disclosure is as follows: [1] A sound-absorbing unit to be installed inside the lumen of a tire, comprising: a resonant sound-absorbing body that absorbs sound inside the lumen; and a support body attached to a mounting surface inside the lumen and supporting the resonant sound-absorbing body with respect to the mounting surface, wherein the resonant sound-absorbing body has a resonator having a hollow portion inside and an opening that opens the hollow portion to the outside, the resonator is configured to be long in a first direction along a first axis, the support body has a first holding portion that has a first insertion space inside and surrounds the first insertion space, and a second holding portion that has a second insertion space inside and surrounds the second insertion space, wherein the first holding portion is inserted inward by a stepped portion provided at one end of the resonator in the first direction and holds the one end of the resonator, and the second holding portion is inserted inward by a stepped portion provided at the other end of the resonator opposite to the one end of the resonator in the first direction and holds the other end of the resonator. [2] The sound-absorbing unit according to [1] above, wherein the resonator has a first portion which is the portion of one end in the first direction, a second portion which is the portion of the other end in the first direction, and an intermediate portion which is the portion between the first portion and the second portion, the circumference of the outer surface of the intermediate portion about the first axis is longer than the circumference of the outer surface of the first portion and the circumference of the outer surface of the second portion about the first axis, the stepped portion provided at one end in the first direction of the resonator is formed by the intermediate portion and the first portion, the stepped portion provided at the other end in the first direction of the resonator is formed by the intermediate portion and the second portion, the first holding portion holds the first portion by inserting the first portion inside, and the second holding portion holds the second portion by inserting the second portion inside. [3] The sound-absorbing unit according to [2] above, wherein the support comprises: a base portion extending in the first direction and attached to the mounting surface; a first leg portion connecting the base portion and the first holding portion; and a second leg portion connecting the base portion and the second holding portion.[4] The sound-absorbing unit according to [3] above, wherein the base portion includes a first base and a second base, the first leg portion includes a first leg body connecting the first base and the first holding portion, and a second leg body connecting the second base and the first holding portion, the second leg portion includes a third leg body connecting the first base and the second holding portion, and a fourth leg body connecting the second base and the second holding portion. [5] The sound-absorbing unit according to [4] above, wherein the first base protrudes from the connection portion with the first leg body and the third leg body toward the opposite side to the second base, and the second base protrudes from the connection portion with the second leg body and the fourth leg body toward the opposite side to the first base. [6] The sound-absorbing unit according to any one of [2] to [5] above, wherein the intermediate portion protrudes more toward the opposite side to the mounting surface than the first portion and the second portion. [7] The sound-absorbing unit according to any one of [1] to [6] above, wherein the resonant sound-absorbing body further comprises: a hollow neck portion extending outside the resonator and having one end communicating with the opening; and a neck support portion connecting the resonator and the neck portion. [8] The sound-absorbing unit according to [7] above, wherein the neck support portion is plate-shaped and extends along the direction of extension of the neck portion. [9] The sound-absorbing unit according to [8] above, wherein the thickness of the neck support portion is greater than the thickness of the neck portion or the thickness of the resonator.

[10] The sound-absorbing unit according to any one of [7] to [9], wherein the resonator extends in a direction intersecting the extending direction of the neck portion and has a neck connecting wall in part that separates the hollow portion from the external space of the resonator, the neck connecting wall is provided with the opening, one end of the neck portion is connected to the neck connecting wall, and the neck portion extends linearly from the connection portion with the neck connecting wall outside the resonator.

[11] The sound-absorbing unit according to any one of [7] to

[10] , wherein the neck portion extends in the first direction.

[12] The sound-absorbing unit according to any one of [7] to

[11] , wherein the support supports the resonant sound absorber such that the neck portion is located on the mounting surface side.

[13] The sound-absorbing unit according to

[12] , wherein the support body supports the resonant sound absorber such that the neck portion is further away from the mounting surface than the portion of the resonator that is closest to the mounting surface.

[14] The sound-absorbing unit according to any one of [7] to

[13] , wherein the second holding portion is inserted inward by the neck portion and the other end of the resonator in the first direction and holds the neck portion and the other end of the resonator in the first direction.

[15] The sound-absorbing unit according to

[14] , wherein one end of the neck portion is connected to the resonator in the first direction within the region between the first holding portion and the second holding portion, the other end of the neck portion opposite to the one end extends outside the region between the first holding portion and the second holding portion via the second holding portion, and the neck support portion connects the resonator and the neck portion at least outside the region between the first holding portion and the second holding portion.

[16] The sound-absorbing unit according to any one of [2] to

[15] , wherein the outer surface of the first portion is provided with a first protrusion in the first direction on the side opposite to the intermediate portion from the first holding portion, or the outer surface of the second portion is provided with a second protrusion in the first direction on the side opposite to the intermediate portion from the second holding portion.

[17] The sound-absorbing unit according to any one of [7] to

[16] , wherein the support body supports the resonant sound-absorbing body such that the neck portion extends along the width direction of the tire.

[18] The sound-absorbing unit according to any one of [1] to

[17] , wherein the resonant sound-absorbing body has a Helmholtz resonance structure that absorbs resonant sounds of 180 Hz to 300 Hz generated in the lumen.

[0099] 1...Resonant sound absorber, 10...Resonator, 11...First part, 11t...First protrusion, 12...Second part, 12t...Second protrusion, 13...Intermediate part, 13d...Stepped wall (neck connection wall), 20...Neck part, 30...Neck support part, 5...Support body, 51...First holding part, 51a...First insertion space, 52...Second holding part, 52a...Second insertion space, 60...Base part, 61...First base, 62...Second base, 71...First leg part, 71a...First leg body, 71b...Second leg body, 72...Second leg part, 72a...Third leg body, 72b...Fourth leg body, 100...Sound absorbing unit, D1...First direction, L1...First axis, R...Hollow part, S...Inner cavity, T...Tire, Ta...Mounting surface.

Claims

1. A sound-absorbing unit to be installed inside the lumen of a tire, comprising: a resonant sound-absorbing body that absorbs sound inside the lumen; and a support body attached to a mounting surface inside the lumen and supporting the resonant sound-absorbing body with respect to the mounting surface, wherein the resonant sound-absorbing body has a resonator having a hollow portion inside and an opening that opens the hollow portion to the outside, the resonator is configured to be elongated in a first direction along a first axis, and the support body has a first holding portion having a first insertion space inside and surrounding the first insertion space, and a second holding portion having a second insertion space inside and surrounding the second insertion space, wherein the first holding portion is inserted inward by a stepped portion provided at one end of the resonator in the first direction to hold the one end of the resonator, and the second holding portion is inserted inward by a stepped portion provided at the other end of the resonator opposite to the one end of the resonator in the first direction to hold the other end of the resonator.

2. The sound-absorbing unit according to claim 1, wherein the resonator comprises: a first portion which is the portion of one end in the first direction; a second portion which is the portion of the other end in the first direction; and an intermediate portion which is the portion between the first portion and the second portion, wherein the circumference of the outer surface of the intermediate portion around the first axis is longer than the circumference of the outer surface of the first portion and the circumference of the outer surface of the second portion around the first axis; the stepped portion provided at one end of the resonator in the first direction is formed by the intermediate portion and the first portion; the stepped portion provided at the other end of the resonator in the first direction is formed by the intermediate portion and the second portion; the first holding portion holds the first portion by inserting the first portion inside; and the second holding portion holds the second portion by inserting the second portion inside.

3. The sound-absorbing unit according to claim 2, wherein the support comprises: a base portion extending in the first direction and attached to the mounting surface; a first leg portion connecting the base portion and the first holding portion; and a second leg portion connecting the base portion and the second holding portion.

4. The sound-absorbing unit according to claim 3, wherein the base portion includes a first base and a second base, the first leg portion includes a first leg body connecting the first base and the first holding portion and a second leg body connecting the second base and the first holding portion, and the second leg portion includes a third leg body connecting the first base and the second holding portion and a fourth leg body connecting the second base and the second holding portion.

5. The sound-absorbing unit according to claim 4, wherein the first base extends outwards from the connection portion with the first leg and the third leg toward the opposite side to the second base, and the second base extends outwards from the connection portion with the second leg and the fourth leg toward the opposite side to the first base.

6. The sound-absorbing unit according to claim 2, wherein the intermediate portion protrudes more than the first portion and the second portion toward the opposite side from the mounting surface.

7. The sound-absorbing unit according to claim 1, further comprising: a hollow neck portion extending outside the resonator and having one end communicating with the opening; and a neck support portion connecting the resonator and the neck portion.

8. The sound-absorbing unit according to claim 7, wherein the resonator extends in a direction intersecting the extending direction of the neck portion and has a neck connecting wall in part that separates the hollow portion from the external space of the resonator, the neck connecting wall is provided with the opening, one end of the neck portion is connected to the neck connecting wall, and the neck portion extends linearly from the connection portion with the neck connecting wall outside the resonator.

9. The sound-absorbing unit according to claim 7, wherein the neck portion extends in the first direction.

10. The sound-absorbing unit according to claim 7, wherein the support body supports the resonant sound-absorbing body such that the neck portion is located on the mounting surface side.

11. The sound-absorbing unit according to claim 7, wherein the second holding portion is inserted inward by the neck portion and the other end of the resonator in the first direction, and holds the neck portion and the other end of the resonator in the first direction.

12. The sound-absorbing unit according to claim 11, wherein one end of the neck portion is connected to the resonator in the region between the first holding portion and the second holding portion in the first direction, the other end of the neck portion opposite to the one end of the neck portion extends outside the region between the first holding portion and the second holding portion via the second holding portion, and the neck support portion connects the resonator and the neck portion at least outside the region between the first holding portion and the second holding portion.

13. The sound-absorbing unit according to claim 2, wherein the outer surface of the first portion is provided with a first protrusion in the first direction on the side opposite to the intermediate portion from the first holding portion, or the outer surface of the second portion is provided with a second protrusion in the first direction on the side opposite to the intermediate portion from the second holding portion.

14. The sound-absorbing unit according to claim 7, wherein the support body supports the resonant sound-absorbing body such that the neck portion extends along the width direction of the tire.

15. The sound-absorbing unit according to any one of claims 1 to 14, wherein the resonant sound-absorbing material has a Helmholtz resonance structure that absorbs resonant sounds of 180 Hz to 300 Hz generated in the lumen.

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