Resonant sound absorber, production method for resonance box of resonant sound absorber, and production method for resonant sound absorber

Abstract

A resonant sound absorber according to the present invention is attached to an attachment surface in an inner cavity of a tire. The resonant sound absorber comprises: a resonance box that has an opening and has a hollow part formed on the interior thereof; and a hollow neck part that is inserted into the opening and affixed to the resonance box, and extends into the hollow part.

Description

Resonance absorber, method for manufacturing a resonance box for a resonance absorber, and method for manufacturing a resonance absorber

[0001] The present disclosure relates to a resonant sound absorber that is attached to the inner cavity of a tire, a method for manufacturing a resonance box for the resonant sound absorber, and a method for manufacturing the resonant sound absorber.

[0002] For example, as described in Patent Document 1, a resonance sound absorber that absorbs sound using the principle of Helmholtz resonance is known. This resonance sound absorber absorbs resonance sounds generated in the tire cavity. This resonance sound absorber has a hollow space formed inside and a resonance box with an opening that connects the hollow space to the outside.

[0003] Japanese Patent Application Laid-Open No. 2021-067767

[0004] In the above-mentioned resonance sound absorber, in order to adjust the frequency of sound absorption, it is conceivable to connect the hollow part of the resonance box with the outside via a hollow neck part. When providing a neck part, it is conceivable to mold the resonance box and the neck part as a single unit. However, the requirements for the resonance box and the neck part are different from each other, and there is a limit to how much these requirements can be met by integral molding.

[0005] Therefore, this disclosure describes a resonance sound absorber that can easily meet the conditions required for the resonance box and neck portion, a method for manufacturing a resonance box for a resonance sound absorber, and a method for manufacturing a resonance sound absorber.

[0006] One aspect of the present disclosure is a resonant sound absorber that is attached to a mounting surface of a tire cavity, and includes a resonance box that has an opening and a hollow portion formed therein, and a hollow neck portion that is inserted into the opening and fixed to the resonance box and extends into the hollow portion.

[0007] The neck portion of this resonance sound absorber is inserted into the opening of the resonance box and fixed to the resonance box. In other words, the resonance box and the neck portion are separate components. Therefore, by assembling the resonance box and the neck portion, a resonance sound absorber that meets the respective requirements for the resonance box and the neck portion can be obtained. In this way, the resonance sound absorber can easily meet the requirements for the resonance box and the neck portion.

[0008] In the above-mentioned resonant sound absorber, the resonance box has a cylindrical main body extending along the axis, a first side wall sealing the cylindrical opening at one axial end of the main body, and a second side wall sealing the cylindrical opening at the other axial end of the main body, the main body having a flat portion facing the mounting surface and a top wall portion forming a hollow portion between the flat portion and the top wall portion, both ends of which in an orthogonal direction perpendicular to the axial direction are connected to both ends of the flat portion in the orthogonal direction, when viewed along the axis, the top wall portion has a shape along a cylindrical surface whose axis is a central axis along the axis, and the opening is provided in the first side wall portion and may be provided at a position adjacent to the flat portion on the first side wall portion.

[0009] In this case, the resonance box has a substantially D-shaped cross section perpendicular to the axis of the main body. The top wall of the resonance box is curved in an arc (substantially arc) shape to form a hollow space between the top wall and the flat section. This prevents stress from concentrating on a single part of the top wall and causing deformation of the hollow space, even when centrifugal force is applied as the tire rotates. In this way, the resonance sound absorber can prevent changes in sound absorption performance even when centrifugal force is applied.

[0010] The opening in the first side wall of the resonance box is located closer to the flat portion. This allows the neck portion inserted into the opening of the resonance box to be received by the flat portion even if it deforms or attempts to deform due to centrifugal force as the tire rotates. This allows the resonance sound absorber to suppress deformation of the neck portion even when centrifugal force is applied.

[0011] In the above-described resonance sound absorber, the flat portion may be provided with a bead extending along the axis, in which case the resonance sound absorber can improve the rigidity of the resonance box.

[0012] In the above-described resonant sound absorber, the beads may include a first bead and a second bead extending parallel to each other along the axis and each protruding toward the hollow portion, and the neck portion may be located between the first and second beads. In this case, the resonant sound absorber can suppress misalignment of the neck portion within the hollow portion by sandwiching the neck portion between the first and second beads.

[0013] In the above-described resonance sound absorber, the resonance box may be provided on the outer surface of the first side wall portion and have a fixed cylindrical portion that communicates with the opening, and the neck portion may be inserted into the fixed cylindrical portion and the opening and fixed to the fixed cylindrical portion. In this case, the neck portion of the resonance sound absorber can be easily fixed to the resonance box using the fixed cylindrical portion.

[0014] Another aspect of the present disclosure is a method for manufacturing a resonance box for the above-mentioned resonant sound absorber, which includes the steps of placing a material for the resonance box in a mold having a cavity corresponding to the outer shape of the resonance box, and blow-molding the material to form the resonance box. This method for manufacturing a resonance box makes it possible to easily manufacture a resonance box having an opening and a hollow portion formed therein by blow-molding.

[0015] According to yet another aspect of the present disclosure, there is provided a method for manufacturing the above-described resonance sound absorber, the method including the steps of manufacturing a resonance box having an opening and a hollow portion formed therein, manufacturing a hollow neck portion, and inserting the neck portion into the opening and fixing the neck portion to the resonance box. In this method for manufacturing a resonance sound absorber, by assembling the neck portion to the resonance box, it is possible to easily manufacture a resonance sound absorber including the resonance box and the neck portion.

[0016] According to various aspects of the present disclosure, the requirements for the resonance box and neck can be easily met.

[0017] FIG. 1 is a schematic cross-sectional view of a tire to which a sound absorbing unit according to an embodiment is attached. FIG. 2 is a schematic perspective view of the sound absorbing unit according to an embodiment, viewed from the open side. FIG. 3 is a schematic front view of the sound absorbing unit according to an embodiment, viewed from the open side. FIG. 4 is a schematic side view for explaining the orientation of a support body attached to the mounting surface of a tire. FIG. 5 is a schematic perspective view of the resonance sound absorber of FIG. 2, viewed from the open side. FIG. 6 is a schematic perspective view of the resonance sound absorber of FIG. 2, viewed from the flat portion side. FIG. 7 is a schematic front view of the resonance sound absorber of FIG. 2, viewed from the open side. FIG. 8 is a schematic cross-sectional view of the resonance sound absorber of FIG. 2, cut along the axis. FIG. 9 is a schematic cross-sectional view of the resonance sound absorber of FIG. 2, cut along a direction perpendicular to the axis.

[0018] Hereinafter, with reference to the drawings, an embodiment of a sound absorbing unit equipped with a resonance sound absorber according to the present disclosure will be described in detail. Note that in the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, numerical ranges indicated using "to" indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0019] FIG. 1 is a schematic cross-sectional view of a tire equipped with a sound-absorbing unit according to an embodiment. In the tire T, cavity resonance can occur, in which the air in the cavity S resonates due to vibrations caused by passing over uneven road surfaces while the vehicle is traveling. The cavity resonance frequency is, for example, approximately 180 Hz to 250 Hz. The cavity resonance frequency varies depending on factors such as the size of the tire T. The sound-absorbing unit 100 according to this embodiment is attached to a mounting surface Ta of the cavity S of the tire T in order to efficiently absorb cavity resonance in the low-frequency band. The mounting surface Ta is the inner circumferential surface of the tread Tb of the tire T.

[0020] In this embodiment, four sound absorbing units 100 are provided within the cavity S of the tire T. In this embodiment, the four sound absorbing units 100 are attached to the attachment surface Ta at positions offset by 90° in the rotational direction of the tire T. However, the number and attachment positions of the sound absorbing units 100 are not limited to the configuration shown in FIG. 1 . Furthermore, the sound absorbing units 100 may be attached within the cavity S of the tire T in combination with other functional components such as a power generation device, sensor device, secondary battery, capacitor, antenna device, transmitter, processor, memory, and circuit, as needed. In this case, it is preferable to attach the sound absorbing units 100 in an appropriate position so that the weight within the tire T is uniform, taking into consideration the weight and number of the attached functional components and sound absorbing units 100.

[0021] A sound absorbing unit 100 according to an embodiment will be described with reference to Figures 2 and 3. Figure 2 is a schematic perspective view of the sound absorbing unit according to the embodiment, viewed from the open side. Figure 3 is a schematic front view of the sound absorbing unit according to the embodiment, viewed from the open side. As shown in Figures 2 and 3, the sound absorbing unit 100 includes a resonance sound absorber 1 and a support body 5. The resonance sound absorber 1 has a Helmholtz resonance structure. The resonance sound absorber 1 absorbs cavity resonance within the inner cavity S of the tire T. The resonance sound absorber 1 has a shape that extends along the axis L1. In other words, the resonance sound absorber 1 has a generally rod-like shape with the axis L1 as its longitudinal direction.

[0022] The support body 5 is attached to the mounting surface Ta of the tire T. The support body 5 supports the resonance sound absorber 1 against the mounting surface Ta. In this embodiment, as an example, three support bodies 5 are provided. The three support bodies 5 are arranged side by side along the axis L1. The three support bodies 5 have the same shape. The resonance sound absorber 1 is supported against the mounting surface Ta by the three support bodies 5. However, the number of support bodies 5 supporting the resonance sound absorber 1 is not limited to three.

[0023] The support body 5 includes a device mounting portion 50, a first base portion 51a, a second base portion 51b, a first leg portion 52a, and a second leg portion 52b. The resonant sound absorber 1 is mounted to the device mounting portion 50. In this embodiment, the device mounting portion 50 is annular. The device mounting portion 50 surrounds and holds the resonant sound absorber 1. The device mounting portion 50 is elastically deformable. The device mounting portion 50 can detachably hold the resonant sound absorber 1 by its elastic force.

[0024] The device mounting portion 50 includes a holding portion 50X and a spaced portion 50Y. In this embodiment, two holding portions 50X and two spaced portions 50Y are provided. The holding portions 50X and the spaced portions 50Y are alternately arranged in the circumferential direction of the annular device mounting portion 50. The holding portion 50X is a portion of the device mounting portion 50 where the inner surface 50a of the device mounting portion 50 abuts against the outer surface 10a of the resonance box 10 of the resonant sound absorber 1. The spaced portion 50Y is a portion of the device mounting portion 50 where the inner surface 50a of the device mounting portion 50 is spaced from the outer surface 10a of the resonance box 10 of the resonant sound absorber 1. The inner surface 50a of the device mounting portion 50 is the inner circumferential surface of the annular device mounting portion 50.

[0025] Fig. 4 is a schematic side view illustrating the orientation of the support body attached to the mounting surface of the tire. Note that in Fig. 4, in order to show the orientation of the device mounting portion 50, only one device mounting portion 50 is shown, and the resonance sound absorber 1 is omitted. Also, as shown in Fig. 4, the perpendicular line to the mounting surface Ta of the tire T is defined as perpendicular line K1. A line perpendicular to perpendicular line K1 is defined as reference line K2. Note that reference line K2 is parallel to the width direction of the tire T. In other words, reference line K2 is parallel to the rotational center line of the tire T.

[0026] 4, the annular device mounting portion 50 is supported by the first leg 52a and the second leg 52b so as to surround a reference line K2 that is perpendicular to the normal K1 of the inner surface 50a. In other words, the annular device mounting portion 50 is supported so as to stand up from the mounting surface Ta. The opening of the annular device mounting portion 50 does not face the mounting surface Ta.

[0027] 2 and 3 , the first base portion 51 a and the second leg portion 52 b are each attached to the mounting surface Ta of the tire T. The first base portion 51 a and the second leg portion 52 b are attached to the mounting surface Ta by, for example, double-sided tape with adhesive surfaces on both sides, adhesive, welding, or the like.

[0028] 3, a sealant layer F may be provided on the mounting surface Ta of the tire. This sealant layer F may have the function of sealing holes in the tire T to prevent punctures of the tire T, for example. In this case, the first base portion 51a and the like are attached to the sealant layer F provided on the mounting surface Ta. That is, the first base portion 51a and the like are attached to the mounting surface Ta via the sealant layer F. The first base portion 51a and the like are attached to the sealant layer F, for example, with an adhesive. Furthermore, the first base portion 51a and the like may be placed on the sealant layer F when the sealant layer F is cured, and may be adhered to the sealant layer F by curing the sealant layer F.

[0029] In this way, attaching the first base portion 51a etc. to the mounting surface Ta includes attaching the first base portion 51a etc. directly to the mounting surface Ta, and attaching the first base portion 51a etc. to the mounting surface Ta via a member such as a sealant layer F.

[0030] The first leg 52a connects the first base portion 51a and the device mounting portion 50. The first leg 52a stands up from the first base portion 51a. The second leg 52b connects the second base portion 51b and the device mounting portion 50. The second leg 52b stands up from the second base portion 51b. The first leg 52a and the second leg 52b support the device mounting portion 50 so that the device mounting portion 50 is spaced apart from the mounting surface Ta when the first base portion 51a and the second base portion 51b are attached to the mounting surface Ta of the tire T. In other words, the first leg 52a and the second leg 52b support the device mounting portion 50 so as to lift it up from the mounting surface Ta of the tire T.

[0031] As described above, the device mounting portion 50 has two spaced apart portions 50Y. The two spaced apart portions 50Y are spaced apart from each other in the circumferential direction of the annular device mounting portion 50. The first leg portion 52a is connected to the outer surface 50b of the device mounting portion 50 at one of the spaced apart portions 50Y. The second leg portion 52b is connected to the outer surface 50b of the device mounting portion 50 at the other of the spaced apart portions 50Y. In this manner, the first leg portion 52a and the second leg portion 52b extend from each of the two spaced apart portions 50Y toward the first base portion 51a and the second base portion 51b, respectively.

[0032] The first base portion 51a protrudes from the end of the first leg portion 52a toward the opposite side to the second base portion 51b. The second base portion 51b protrudes from the end of the second leg portion 52b toward the opposite side to the first base portion 51a.

[0033] The material of the support body 5 may be, for example, a dynamically crosslinked thermoplastic elastomer (TPV) or vulcanized rubber such as styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), butadiene rubber (BR), chloroprene rubber (CR), and isoprene rubber (IR). By using these materials, a support body 5 having excellent elasticity, heat resistance, and flexibility and suitable as a supporting member within the cavity S of the tire T can be obtained.

[0034] However, the material of the support 5 is not limited to these. In addition, the material of the support 5 may be a thermoplastic elastomer other than the dynamically crosslinked thermoplastic elastomer (TPV) (for example, a styrene-based elastomer (TPS), a polyolefin-based elastomer (TPO), a polyurethane-based elastomer (TPU), a polyester-based elastomer (TPEE), a polyester-based elastomer (TPC), etc.). Furthermore, the material of the support 5 may be various foam materials (for example, foamed rubber, foamed urethane, etc.).

[0035] As shown in Figures 2 and 3, the resonance sound absorber 1 includes a resonance box 10 and a neck portion 20. The resonance sound absorber 1 will be described in detail below. Figure 5 is a schematic perspective view of the resonance sound absorber of Figure 2, viewed from the open side. Figure 6 is a schematic perspective view of the resonance sound absorber of Figure 2, viewed from the flat portion side. Figure 7 is a schematic front view of the resonance sound absorber of Figure 2, viewed from the open side. Figure 8 is a schematic cross-sectional view of the resonance sound absorber of Figure 2, taken along the axis. Figure 9 is a schematic cross-sectional view of the resonance sound absorber of Figure 2, taken along a direction perpendicular to the axis. Figure 9 is also a cross-sectional view taken along line IX-IX in Figure 8.

[0036] As shown in each drawing, the direction along the axis L1 (axis L1 direction) is defined as the first direction D1, the direction perpendicular to the first direction D1 is defined as the second direction D2, and the direction perpendicular to the first direction D1 and the second direction D2 is defined as the third direction D3. The first direction D1 is the axis L1 direction. The second direction D2 is also an orthogonal direction perpendicular to the axis L1 direction. The third direction D3 is also the height direction of the resonance box 10. When the resonance sound absorber 1 is attached to the mounting surface Ta of the tire T by the support body 5, the third direction D3 is also the direction along the perpendicular line K1 to the mounting surface Ta.

[0037] 5 to 9, the resonance box 10 of the resonance sound absorber 1 has a hollow portion R formed therein (see FIG. 8). The resonance box 10 has an opening 10b that connects the hollow portion R with the external space (see FIG. 8). The resonance box 10 has a main body 11, a first side wall 12, a second side wall 13, and a fixed cylinder 16 (see FIG. 8).

[0038] The main body 11 has a cylindrical shape extending in a first direction D1 along the axis L1. The first side wall 12 has a plate shape. The first side wall 12 seals a cylindrical opening 11a (see FIG. 8) at one end of the main body 11 in the first direction D1. The first side wall 12 has an opening 10b. The second side wall 13 has a plate shape. The second side wall 13 seals a cylindrical opening 11b (see FIG. 8) at the other end of the main body 11 in the first direction D1. The second side wall 13 faces the opening 10b provided in the first side wall 12. In this way, the resonance box 10 has a shape in which the portions other than the opening 10b are closed.

[0039] The cylindrical main body 11 has a flat portion 14 and a top wall portion 15. The flat portion 14 is generally plate-shaped. The flat portion 14 is formed in a generally rectangular plate shape that is long in the first direction D1 and short in the second direction D2. The flat portion 14 faces the mounting surface Ta of the tire T. The resonance sound absorber 1 is attached to the device mounting portion 50 of the support body 5 so that the flat portion 14 of the resonance box 10 faces the mounting surface Ta when the sound absorbing unit 100 is attached to the mounting surface Ta of the tire T. Specifically, the resonance sound absorber 1 is attached to the device mounting portion 50 so that the flat portion 14 of the resonance box 10 faces the first base portion 51 a and the second base portion 51 b.

[0040] The top wall portion 15 forms a hollow portion R between itself and the flat portion 14. The top wall portion 15 covers the hollow portion R from the side opposite the flat portion 14. Both ends of the top wall portion 15 in the second direction D2 (ends 15a and 15b) are connected to both ends of the flat portion 14 in the second direction D2 (ends 14a and 14b) (see FIG. 9 ). The top wall portion 15 is curved in an arc shape when viewed along the first direction D1.

[0041] More specifically, as shown in Fig. 9, when viewed along the axis L1 (first direction D1), the top wall portion 15 has a shape that follows a cylindrical surface M whose axis is a central axis L2 that follows the axis L1. The cylindrical surface M whose axis is the central axis L2 is a cylindrical surface that surrounds the central axis L2 and is centered on the central axis L2. However, the shape of the top wall portion 15 is not limited to being completely along the cylindrical surface M. The top wall portion 15 may have any shape that is close to a shape that follows the cylindrical surface M.

[0042] 7 and 8 , opening 10b provided in first side wall portion 12 is located closer to flat portion 14 than the position of center axis L2 of cylindrical surface M along which top wall portion 15 extends, when viewed along axis L1 (first direction D1). In other words, opening 10b is located near the edge of first side wall portion 12 on the side connected to flat portion 14. Opening 10b is located closer to the edge of first side wall portion 12 connected to flat portion 14 than the edge connected to top wall portion 15.

[0043] The thickness of the flat portion 14 is thicker than the thickness of an upper wall portion 15c of the ceiling wall portion 15 that faces the flat portion 14. The upper wall portion 15c is a portion of the ceiling wall portion 15 that faces the flat portion 14 across the central axis L2. The upper wall portion 15c and the flat portion 14 face each other in the third direction D3. For example, the thickness of the flat portion 14 may be 1.1 times or more the thickness of the upper wall portion 15c of the ceiling wall portion 15. For example, the thickness of the ceiling wall portion 15 may be approximately 0.4 mm or less. Furthermore, the thickness of the second side wall portion 13 is thicker than the thickness of the upper wall portion 15c of the ceiling wall portion 15. For example, the thickness of the second side wall portion 13 may be 1.1 times or more the thickness of the upper wall portion 15c of the ceiling wall portion 15.

[0044] The flat portion 14 is provided with a first bead (bead) 14c and a second bead (bead) 14d extending along the first direction D1 (axis L1). The first bead 14c and the second bead 14d extend parallel to each other along the first direction D1. The first bead 14c and the second bead 14d provided on the flat portion 14 protrude toward the hollow portion R (inside the resonance box 10). As shown in FIG. 9 , for example, the first bead 14c protrudes toward the hollow portion R so that a cross section cut along a direction perpendicular to the axis L1 has a substantially arc-shaped cross section. Similar to the first bead 14c, the second bead 14d also protrudes toward the hollow portion R so that it has a substantially arc-shaped cross section. However, the shapes of the first bead 14c and the second bead 14d are not limited to a substantially arc-shaped cross section and may have other shapes. The first bead 14c and the second bead 14d may have any shape as long as they protrude toward the hollow portion R.

[0045] As shown in FIG. 8 , the fixed cylinder portion 16 is provided on the outer surface of the first side wall portion 12. The outer surface of the first side wall portion 12 is the surface of the resonance box 10 that faces outward. In other words, the outer surface of the first side wall portion 12 is also part of the outer surface 10a of the resonance box 10. The fixed cylinder portion 16 has a tubular shape. In the present embodiment, the fixed cylinder portion 16 has a cylindrical shape, for example. The fixed cylinder portion 16 communicates with an opening 10b provided in the first side wall portion 12. As a result, the hollow portion R within the resonance box 10 and the external space communicate with each other via the opening 10b provided in the first side wall portion 12 and the fixed cylinder portion 16.

[0046] The neck portion 20 is disposed within the resonance box 10. In this embodiment, the entire tube main body portion 21 of the neck portion 20 is disposed within the resonance box 10. However, the base end 20a of the neck portion 20 may extend outward from the resonance box 10 (here, the fixed tube portion 16). A hollow portion 20c is formed inside the neck portion 20. The base end 20a and the tip end 20b of the neck portion 20 are open ends that expose the hollow portion 20c.

[0047] The neck portion 20 has a tube main body portion 21 and a folded portion 22. The tube main body portion 21 has a tubular shape with a hollow portion 20c formed inside. In the present embodiment, the tube main body portion 21 has a cylindrical shape, as an example. The folded portion 22 has a cylindrical shape. The folded portion 22 is arranged at the base end 20a of the neck portion 20 so as to surround the tube main body portion 21. In the present embodiment, the folded portion 22 has a cylindrical shape, as an example. A predetermined gap is provided between the outer peripheral surface of the tube main body portion 21 and the inner peripheral surface of the folded portion 22. The tube main body portion 21 and the folded portion 22 are connected to each other at the base end 20a of the neck portion 20. The fixed tube portion 16 of the resonance box 10 can be inserted into the gap between the outer peripheral surface of the tube main body portion 21 and the inner peripheral surface of the folded portion 22.

[0048] The neck portion 20 is inserted into the fixed cylinder portion 16 and the opening 10b of the resonance box 10 and fixed to the resonance box 10, and extends into the hollow portion R of the resonance box 10. In other words, the tip 20b of the neck portion 20 is located within the hollow portion R. The neck portion 20 is inserted so as to extend in a direction along the axis L1. As a result, the hollow portion R of the resonance box 10 and the external space communicate with each other via the hollow portion 20c of the neck portion 20.

[0049] The neck portion 20 is inserted into the fixed cylinder portion 16 of the resonance box 10 and the opening 10b so that the fixed cylinder portion 16 of the resonance box 10 fits into the gap between the outer circumferential surface of the cylinder main body portion 21 and the inner circumferential surface of the folded portion 22. In other words, the cylinder main body portion 21 of the neck portion 20 is inserted into the fixed cylinder portion 16 of the resonance box 10 and the opening 10b. The neck portion 20 is fixed to the fixed cylinder portion 16 of the resonance box 10. The neck portion 20 and the fixed cylinder portion 16 of the resonance box 10 are fixed to each other by, for example, engaging a recess with a protrusion, engaging a thread with a thread groove, or by adhesive. There are no particular limitations on the method for fixing the neck portion 20 to the fixed cylinder portion 16 of the resonance box 10.

[0050] As described above, the opening 10b in the first side wall 12 is located close to the flat portion 14. Therefore, the tube main body 21 of the neck portion 20 inserted into the opening 10b in the first side wall 12 is located on or near the surface of the flat portion 14. The tube main body 21 of the neck portion 20 inserted into the resonance box 10 is located between the first bead 14c and the second bead 14d when viewed along the third direction D3 (see FIG. 9 ).

[0051] As described above, the resonance box 10 and the neck portion 20 are separate components in the resonance sound absorber 1. The neck portion 20 is inserted into the fixed cylindrical portion 16 and the opening 10b of the resonance box 10, and is fixed to the fixed cylindrical portion 16 of the resonance box 10. This allows the resonance box 10 and the neck portion 20 to be integrated.

[0052] For example, the resonance box 10 is required to be more rigid than the neck portion 20 so that the hollow portion R is not crushed by centrifugal force when the tire T rotates. Furthermore, the resonance sound absorber 1 is also required to be lightweight overall. Thus, the resonance sound absorber 1 is required to be able to respond to various conditions. In this embodiment, the resonance box 10 and the neck portion 20 of the resonance sound absorber 1 are separate components. Therefore, different materials can be used for the resonance box 10 and the neck portion 20 so that the respective requirements are met. Furthermore, different manufacturing methods can be used for the resonance box 10 and the neck portion 20 so that the respective requirements are met.

[0053] For example, the material forming the resonance box 10 may be a material whose elastic modulus itself is higher than that of the material forming the neck portion 20. This makes it possible to suppress deformation of the resonance box 10. The material forming the resonance box 10 may be a material whose rigidity itself is higher than that of the material forming the neck portion 20. This makes it possible to suppress deformation of the resonance box 10. The material forming the resonance box 10 may be a material whose specific gravity itself is higher than that of the material forming the neck portion 20. This makes it possible to reduce the weight of the neck portion 20.

[0054] For example, the materials of the resonance box 10 and the neck portion 20 may be thermoplastics such as polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polycarbonate (PC), polyacetal (POM), polyphenylene sulfide (PPS), etc.; thermoplastic elastomers such as olefin-based (TPO), dynamically crosslinked (TPV), styrene-based (TPS), polyurethane-based (TPU), and polyester-based (TPEE); or vulcanized rubbers such as natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), butadiene rubber (BR), and chloroprene rubber (CR).

[0055] The resonance box 10 can be manufactured by blow molding, as an example. In this case, the manufacturing method of the resonance box 10 of the resonance sound absorber 1 includes the steps of placing the material (parison) of the resonance box 10 in a mold in which a cavity corresponding to the outer shape of the resonance box 10 is formed, injecting gas into the material to form the resonance box 10 by blow molding, and removing the molded resonance box 10 from the mold. Note that the air blowing port that injects gas into the material in the step of molding the resonance box 10 by blow molding serves as the opening 10b of the resonance box 10. By molding the resonance box 10 by blow molding, the resonance box 10 having the hollow portion R can be easily manufactured.

[0056] As described above, the resonance box 10 is formed by blow molding so as to satisfy various conditions, such as the condition for the position of the opening 10b provided in the first side wall 12, and the condition for the difference in thickness between the flat portion 14 and the second side wall 13 and the upper wall 15c of the top wall 15. Specifically, the resonance box 10 having the above-described configuration is obtained by adjusting, for example, the temperature and temperature distribution of the mold, the temperature and temperature distribution of the material of the resonance box 10, the position at which air is supplied into the material placed in the mold (the position that will become the opening 10b), the pressure of the gas supplied into the material placed in the mold, the temperature difference between the mold and the material, the dimensional difference between the mold and the material, the material of the resonance box 10, and the like.

[0057] The neck portion 20 may be manufactured by, for example, injection molding, extrusion molding, 3D printing, salt coagulation, or the like. However, there are no particular limitations on the manufacturing method for the neck portion 20. As such, since the resonance box 10 and the neck portion 20 are separate components, they can be manufactured by different manufacturing methods.

[0058] Next, we will explain the manufacturing method of the resonance sound absorber 1. The manufacturing method of the resonance sound absorber 1 includes the steps of manufacturing the resonance box 10 having the opening 10b and the hollow portion R formed therein, manufacturing the hollow neck portion 20, and inserting the neck portion 20 into the opening 10b of the resonance box 10 and fixing the neck portion 20 to the resonance box 10. In this way, the resonance box 10 and the neck portion 20, which are separate components, are assembled to obtain the resonance sound absorber 1.

[0059] As described above, the neck portion 20 of the resonance absorber 1 is inserted into the opening 10b of the resonance box 10 and fixed to the resonance box 10. In other words, the resonance box 10 and the neck portion 20 are separate components. Therefore, by assembling the resonance box 10 and the neck portion 20, it is possible to obtain a resonance absorber 1 that satisfies the respective conditions required of the resonance box 10 and the neck portion 20. In this way, the resonance absorber 1 can easily satisfy the conditions required of the resonance box 10 and the neck portion 20.

[0060] The resonance box 10 has a flat portion 14 and a top wall portion 15. The top wall portion 15 has a shape that follows a cylindrical surface M with a central axis L2 as its axis. In this case, the cross section of the resonance box 10 in a direction perpendicular to the axis L1 of the main body portion 11 is approximately D-shaped. The top wall portion 15 that constitutes the resonance box 10 is curved in an arc shape so as to form a hollow portion R between it and the flat portion 14. The resonance sound absorber 1 is attached to the mounting surface Ta of the tire T so that the flat portion 14 of the resonance box 10 faces the mounting surface Ta. This prevents stress concentration and deformation of a portion of the top wall portion 15, even when centrifugal force is applied as the tire T rotates, and thus prevents deformation of the hollow portion R. In this way, the resonance sound absorber 1 is able to prevent changes in sound absorption performance even when centrifugal force is applied.

[0061] Furthermore, the opening 10b provided in the first side wall portion 12 of the resonance box 10 is located on the side closer to the flat portion 14. As a result, even if the neck portion 20 inserted into the opening 10b of the resonance box 10 is deformed or attempts to deform due to the application of centrifugal force as the tire T rotates, it is received by the flat portion 14. As a result, the resonance sound absorber 1 can suppress deformation of the neck portion 20 even when centrifugal force is applied.

[0062] The flat portion 14 of the resonance box 10 is provided with a first bead 14c and a second bead 14d extending along the axis L1. In this case, the resonance sound absorber 1 can improve the rigidity of the resonance box 10.

[0063] The neck portion 20 is located between the first bead 14 c and the second bead 14 d. In this case, the resonant sound absorber 1 can suppress misalignment of the neck portion 20 within the hollow portion R by sandwiching the neck portion 20 between the first bead 14 c and the second bead 14 d.

[0064] The resonance box 10 has a fixed cylindrical portion 16 attached to the outer surface of the first side wall portion 12. The neck portion 20 is inserted into the fixed cylindrical portion 16 and the opening 10b of the resonance box 10 and fixed to the fixed cylindrical portion 16. In this case, the neck portion 20 of the resonance absorber 1 can be easily fixed to the resonance box 10 using the fixed cylindrical portion 16.

[0065] The manufacturing method of the resonance box 10 of the resonance sound absorber 1 includes a step of molding the resonance box 10 by blow molding. In this manufacturing method of the resonance box 10, the resonance box 10 having the opening 10b and the hollow portion R formed therein can be easily manufactured by blow molding.

[0066] The method for manufacturing the resonance sound absorber 1 includes a step of manufacturing the resonance box 10, a step of manufacturing the neck portion 20, and a step of inserting the neck portion 20 into the opening 10b of the resonance box 10 and fixing the neck portion 20 to the resonance box 10. In this method for manufacturing a resonance sound absorber, by assembling the neck portion 20 to the resonance box 10, the resonance sound absorber 1 including the resonance box 10 and the neck portion 20 can be easily manufactured.

[0067] As described above, the resonance box 10 can be molded by blow molding. In blow molding, the farther the air outlet (air hole) for blowing air into the material (parison) of the resonance box 10 is from the center of the resonance box 10 (the greater the eccentricity), the more difficult it is to deliver air throughout the resonance box 10. Specifically, as shown in FIG. 7 , the farther the opening 10b is from the central axis L2 of the top wall 15, the more difficult it is to deliver air throughout the resonance box 10. For this reason, it is conceivable to position the opening 10b at the central axis L2. However, if the opening 10b is positioned at the central axis L2, the neck portion 20 inserted into the opening 10b will be significantly separated from the inner wall surface of the resonance box 10 and will float within the hollow portion R. If centrifugal force is applied to the neck portion 20 in this state, the neck portion 20 will be significantly deformed.

[0068] Therefore, the main body 11 of the resonance box 10 has a shape including a flat portion 14 and a top wall portion 15. In other words, the main body 11 has a substantially D-shaped cross section. The flat portion 14 is located closer to the central axis L2 of the cylindrical surface M along which the top wall portion 15 extends than the top wall portion 15. The opening 10b provided in the first side wall portion 12 is located closer to the flat portion 14. This allows the flat portion 14 to support the neck portion 20 while positioning the opening 10b closer to the central axis L2. Therefore, the resonance box 10 can suppress deformation of the neck portion 20 using the flat portion 14. Furthermore, by positioning the opening 10b closer to the central axis L2, it becomes easier to introduce air into the entire resonance box 10 during blow molding.

[0069] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the resonance sound absorber 1 is not limited to being attached to the mounting surface Ta of the tire T by the support body 5. For example, the resonance sound absorber 1 may be attached directly to the mounting surface Ta of the tire T.

[0070] The gist of the present disclosure is as follows: [1] A resonance sound absorber to be attached to a mounting surface of a tire cavity, the resonance sound absorber comprising: a resonance box having an opening and a hollow portion formed therein; and a hollow neck portion that is inserted into the opening, fixed to the resonance box, and extends into the hollow portion. [2] The resonance box has a cylindrical main body extending along an axis, a first side wall sealing an opening at one end of the main body in the axial direction, and a second side wall sealing an opening at the other end of the main body in the axial direction, the main body having a flat portion facing the mounting surface, and a top wall portion forming the hollow portion between the flat portion and the top wall portion, the both ends of which in an orthogonal direction perpendicular to the axial direction are connected to both ends of the flat portion in the orthogonal direction, when viewed along the axis, the top wall portion has a shape along a cylindrical surface whose axis is a central axis along the axis, and the opening is provided in the first side wall portion and is provided in the first side wall portion adjacent to the flat portion. [3] The resonance sound absorber according to [2] above, wherein the flat portion is provided with a bead extending along the axis. [4] The sound-resonating body according to [3] above, wherein the beads include a first bead and a second bead that extend parallel to each other along the axis and each protrude toward the hollow portion, and the neck portion is located between the first bead and the second bead. [5] The sound-resonating body according to any one of [2] to 4] above, wherein the resonance box is provided on the outer surface of the first side wall portion and includes a cylindrical portion that communicates with the opening, and the neck portion is inserted into the cylindrical portion and the opening and fixed to the cylindrical portion. [6] A method for manufacturing a resonance box for a sound-resonating body according to any one of [1] to [5] above, comprising the steps of: placing a material for the resonance box in a mold having a cavity formed therein that corresponds to the outer shape of the resonance box; and blow-molding the material by injecting gas into the material to form the resonance box.[7] A method for manufacturing a resonance sound absorber according to any one of [1] to [5] above, comprising: a step of manufacturing a resonance box having an opening and a hollow portion formed therein; a step of manufacturing a hollow neck portion; and a step of inserting the neck portion into the opening and fixing the neck portion to the resonance box.

[0071] 1...resonant sound absorber, 10...resonant box, 10b...opening, 11...main body, 12...first side wall, 13...second side wall, 14...flat portion, 14c...first bead (bead), 14d...second bead (bead), 15...top wall, 16...fixed cylinder, 20...neck, L1...axis, L2...central axis, R...hollow portion, S...inner cavity, T...tire, Ta...mounting surface.

Claims

1. A resonant sound absorber to be attached to the mounting surface of the tire cavity, comprising: a resonance box having an opening and a hollow portion formed therein; and a hollow neck portion that is inserted into the opening, fixed to the resonance box, and extends into the hollow portion.

2. The resonance sound absorber according to claim 1, wherein the resonance box has: a cylindrical main body extending along an axis; a first side wall sealing a cylindrical opening at one end of the main body in the axial direction; and a second side wall sealing a cylindrical opening at the other end of the main body in the axial direction; the main body has: a flat portion facing the mounting surface; and a top wall portion forming the hollow portion between itself and the flat portion and having both ends in an orthogonal direction perpendicular to the axial direction connected to both ends of the flat portion in the orthogonal direction, the top wall portion having a shape along a cylindrical surface whose axis is a central axis along the axis when viewed along the axis; and the opening is provided in the first side wall portion and is provided in the first side wall portion at a position adjacent to the flat portion.

3. A resonant sound absorber according to claim 2, wherein the flat portion is provided with a bead extending along the axis.

4. A resonant sound absorber as described in claim 3, wherein the beads have a first bead and a second bead that extend parallel to each other along the axis and each protrude toward the hollow portion, and the neck portion is located between the first bead and the second bead.

5. A resonator sound absorber as described in claim 2, wherein the resonance box is provided on the outer surface of the first side wall portion and has a cylindrical portion that communicates with the opening, and the neck portion is inserted into the cylindrical portion and the opening and fixed to the cylindrical portion.

6. A method for manufacturing a resonance box for a sound-resonating body as claimed in any one of claims 1 to 5, comprising the steps of: placing a material for the resonance box in a mold having a cavity formed therein that corresponds to the external shape of the resonance box; and blow-molding the material by injecting gas into the material to form the resonance box.

7. A method for manufacturing a sound-resonating body according to any one of claims 1 to 5, comprising the steps of: manufacturing a resonance box having an opening and a hollow space formed therein; manufacturing a hollow neck; and inserting the neck into the opening and fixing the neck to the resonance box.

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