JP2017109701A - Sound absorption member and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorption member and a pneumatic tire capable of achieving both of weight saving and reduction of cavernous resonance.SOLUTION: A sound absorption member of the invention is provided on a lumen of a tire. The sound absorption member comprises a thin film part and a porous part having a cell number which is 5-30/25 mm, and having 25% hardness which is 20-200 N. A pneumatic tire of the invention is configured so that, the sound absorption member is provided on a surface on the lumen side of the tire.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound absorbing member and a pneumatic tire.

  In pneumatic tires, it is required to reduce noise during vehicle travel and to improve quietness. As noise during vehicle running, resonance vibration of air (cavity resonance) occurring in the inner cavity of the tire is known. In recent years, in the tire inner cavity formed by a rim and a pneumatic tire attached to the rim. In addition, it has been proposed to suppress the cavity resonance by disposing a sound damper made of a porous material (see, for example, Patent Document 1).

JP-A-2005-001428

  By the way, in the above-mentioned conventional sound damper for placement in the lumen of a pneumatic tire, the sound absorption coefficient of the sound damper at the peak frequency (200 Hz to 250 Hz) of the cavity resonance sound is not necessarily high enough. Further, when trying to increase the sound absorption coefficient of the sound damping body, it is necessary to increase its volume, which may increase the weight significantly.

  Accordingly, an object of the present invention is to provide a sound absorbing member and a pneumatic tire that can achieve both weight reduction and reduction of cavity resonance noise.

The sound absorbing member of the present invention is a sound absorbing member disposed in the inner cavity of a tire, and the sound absorbing member has a thin film portion, 5 to 30 cells / 25 mm, and a 25% hardness of 20 to 20%. And a porous portion that is 200 N.
According to the sound absorbing member of the present invention, both weight reduction and reduction of cavity resonance sound can be achieved.
In the present invention, “number of cells” is measured according to JIS K 6400-1 Annex 1: 2012, and “25% hardness” is measured according to JIS K 6400-2: 2012. It shall be.

In the sound absorbing member of the present invention, it is preferable that the thin film portion covers at least a part of the surface of the porous portion.
According to this configuration, cavity resonance can be effectively reduced.

In the sound absorbing member of the present invention, it is preferable that the porous portion has a thickness of 10 to 50 mm.
According to this configuration, the weight of the sound absorbing member can be reduced while maintaining the strength of the sound absorbing member.
In the present invention, “the thickness of the porous portion” refers to the length measured along the thickness direction of the thin film portion of the porous portion.

In the sound absorbing member of the present invention, it is preferable that the thin film portion has a thickness of 5 to 30 μm.
According to this configuration, cavity resonance can be effectively reduced.

The pneumatic tire of the present invention is characterized in that the above-described sound absorbing member is disposed on the surface of the tire on the lumen side.
According to the pneumatic tire of the present invention, both weight reduction and reduction of cavity resonance noise can be achieved.

In the pneumatic tire according to the present invention, a plurality of the sound absorbing members are disposed on the surface on the lumen side of the tire so as to be spaced apart from each other in the tire circumferential direction, and the side surface of the sound absorbing member positioned in the tire circumferential direction. Further, it is preferable that at least a part of the thin film portion is formed.
According to this configuration, the cavity resonance can be effectively reduced without increasing the weight.

In the pneumatic tire of the present invention, the area of the thin film portion included in one sound absorbing member in the direction perpendicular to the tire circumferential direction is perpendicular to the tire circumferential direction of the tire lumen. The cross-sectional area in the direction is preferably 50% or more.
According to this configuration, cavity resonance can be effectively reduced.

In the present invention, the “area in the direction perpendicular to the tire circumferential direction” of the thin film portion and the porous portion means that the thin film portion and the porous portion are in a plane perpendicular to the tire circumferential direction. On the other hand, it refers to the area when projected along the tire circumferential direction, and only the area of the shape projected on the surface is included in the area, and the thin film portion and the porous portion are relative to the surface. Even if an overlapping portion is generated by projection, the area of the overlapping portion is not counted as an overlapping number (for example, when a thin film portion having two layers in the tire circumferential direction is provided in the sound absorbing member).
Further, in the present invention, “the cross-sectional area of the tire lumen in a direction perpendicular to the tire circumferential direction” means that the tire is assembled to an applicable rim and an internal pressure of 50 kPa is applied to the tire in an unloaded state. It refers to the cross-sectional area of the lumen (region surrounded by the inner surface of the tire and the surface of the rim).
“Applicable rim” is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European Tire and Rim). STANDARDDS MANUAL of Technical Organization, RM (The TIRE and Rim Association, Inc.) YEAR BOOK of the TRA in the United States, etc. Rim). The purpose of setting the internal pressure to 50 kPa is that the bead portion of the tire is assembled to the applicable rim to make the rim width, and the internal pressure is low enough to maintain the shape of the tire case line. In addition, the application of the internal pressure here may be performed by using an inert gas such as nitrogen gas in addition to air.

  According to the present invention, it is possible to provide a sound absorbing member and a pneumatic tire that can achieve both weight reduction and reduction of cavity resonance noise.

A part in the tire equatorial plane showing a sound absorbing member and a pneumatic tire according to an embodiment of the present invention in a state where a pneumatic tire in which the sound absorbing member is disposed on the inner surface of the tire is mounted on a rim. It is sectional drawing. FIG. 2 is a cross-sectional view in a direction perpendicular to the tire circumferential direction, showing the sound absorbing member and pneumatic tire of FIG. 1 in the same state as in FIG. 1. It is a perspective view which shows an example of the sound absorption member shown in FIG. It is a partial cross section figure in the tire equator surface which shows the modification of the sound-absorbing member and pneumatic tire of FIG. 1 in the same state as FIG. A direction perpendicular to the tire circumferential direction, showing the example in which the sound absorbing member shown in FIG. 1 is disposed on the rim surface of the pneumatic tire and rim assembly, with the pneumatic tire mounted on the rim. FIG. FIG. 6 is a partial cross-sectional view of the tire equatorial plane showing another modification of the sound absorbing member and the pneumatic tire of FIG. 1 in the same state as in FIG. 1. FIG. 7 is a cross-sectional view in a direction perpendicular to the tire circumferential direction, showing the sound absorbing member and pneumatic tire of FIG. 6 in the same state as in FIG. 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a tire in which a sound absorbing member 1 and a pneumatic tire (hereinafter also referred to as a tire) 2 according to an embodiment of the present invention are disposed on a surface TS of the tire 2 on the lumen I side. FIG. 2 is a partial cross-sectional view of the tire equatorial plane C, showing a state where 2 is mounted on the rim R. 2 is a cross-sectional view in a direction perpendicular to the tire circumferential direction, showing the sound absorbing member 1 and the tire 2 of FIG. 1 in a state similar to that of FIG.

First, the sound absorbing member 1 of the present embodiment will be described with reference to the drawings.
The sound absorbing member 1 is disposed in the lumen I of the tire 2, and specifically, for example, as shown in FIGS. 1, 2, 4, 6, and 7, the surface of the tire 2 on the lumen I side. (Hereinafter also referred to as the inner surface of the tire 2), or disposed on the surface RS of the rim R to which the tire 2 is mounted, as shown in FIG. Can be set up.

  The shape of the sound absorbing member 1 is not particularly limited, but can be a rectangular parallelepiped as shown in FIGS. In addition, the shape of the sound absorbing member 1 can be, for example, a polyhedron such as a cube, a hemisphere, or the like. The shape of the sound absorbing member 1 is, for example, an annular shape (as shown in FIG. 6) when the sound absorbing member 1 is disposed in the lumen I of the tire 2 in a sectional view on the tire equatorial plane C. Of the inner surface TS of the tire 2), an inverted T-shape, etc., and in a cross-sectional view in a direction perpendicular to the tire circumferential direction, for example, matched to the shape of the lumen I of the tire 2 It can be shaped.

  The sound absorbing member 1 includes a thin film portion 3 and a porous portion 4 having a cell count of 5 to 30 cells / 25 mm and a 25% hardness of 20 to 200 N. Specifically, the thin film portion 3 of the sound absorbing member 1 can have a thickness of, for example, 5 to 30 μm, and the porous portion 4 can have a thickness of 10 to 50 mm.

As shown in FIG. 1, the thin film portion 3 of the sound absorbing member 1 covers at least part of the surface of the porous portion 4. In the illustrated example, the thin film portion 3 is a planar surface of the porous portion 4. Has a first thin film portion 31 covering the surface along the surface. In the illustrated example, the thin film portion 3 further includes a second thin film portion 32 substantially parallel to the first thin film portion 31 inside the porous portion 4, and has a two-layer structure here. ing.
In the illustrated example, the thin film portion 3 has a two-layer structure. However, the thin film portion 3 can be only one of the first thin film portion 31 and the second thin film portion 32, or still another layer. Three or more layers can be formed by providing the thin film portion on the surface of the porous portion 4 opposite to the first thin film portion 31 or inside the porous portion 4. Furthermore, the thin film portion 3 can be provided as one or more small piece portions dispersed inside or on the surface of the porous portion 4.

Here, the operation and effect of the sound absorbing member according to the embodiment of the present invention will be described.
When the tire 2 rolls, a cavity resonance sound, which is a sound wave standing in the tire circumferential direction, is generated in the inner cavity I of the tire 2, but the sound absorbing member 1 of the present embodiment has the thin film portion 3 and the porous sound. Since the sound absorbing member 1 is disposed in the inner cavity I of the tire 2, the thin film portion 3 absorbs the cavity resonance sound, and the porous portion 4 supports the thin film portion 3 to support the thin film. Absorbs the vibration of part 3. Therefore, the cavity resonance can be reduced by the combination of the thin film portion 3 and the porous portion 4. Moreover, since the porous part 4 of the sound absorbing member 1 of the present embodiment has 5 to 30 cells / 25 mm and 25% hardness of 20 to 200 N, the porous part 4, and hence the sound absorbing member 1. Can be reduced in weight.
Therefore, according to the sound absorbing member 1 of the present embodiment, both weight reduction and reduction of cavity resonance noise can be achieved.
If the number of cells of the porous portion 4 of the sound absorbing member 1 is less than 5/25 mm or the 25% hardness is less than 20 N, the strength of the sound absorbing member 1 may be reduced. Further, when the number of cells of the porous portion 4 of the sound absorbing member 1 exceeds 30 cells / 25 mm or the 25% hardness exceeds 200 N, the weight of the sound absorbing member 1 increases or the expected effect of reducing the cavity resonance noise is sufficient. There is a possibility that it cannot be obtained. Further, when the sound absorbing member 1 is composed only of the porous portion 4, it is necessary to make the sound absorbing member 1 having a large volume in order to sufficiently absorb it, and the weight of the sound absorbing member 1 is increased.

  In the sound absorbing member 1, the number of cells of the porous portion 4 is 15 to 25 / from the viewpoint of reducing the weight of the sound absorbing member 1 and sufficiently reducing the cavity resonance sound while maintaining the strength of the sound absorbing member 1. More preferably, it is 25 mm. From the same viewpoint, the 25% hardness of the porous portion 4 is more preferably 20 to 100N. Furthermore, from the same viewpoint, the thickness of the porous portion 4 is preferably 10 to 50 mm, and more preferably 30 to 50 mm.

  The thin film portion 3 preferably has a thickness of 5 to 30 μm, and more preferably 5 to 15 μm, from the viewpoint of effectively reducing the cavity resonance sound by absorbing it. If the thickness of the thin film portion 4 is less than 5 μm, the strength may be reduced.

Further, as shown in FIG. 1, the thin film portion 3 preferably covers at least a part of the surface of the porous portion 4. According to this configuration, since the thin film portion 3 covers the surface of the porous portion 4, the thin film portion 3 located on the surface of the sound absorbing member 1 is directly exposed to the cavity resonance sound. Thus, cavity resonance can be reduced. Also, the contact with the porous part 4 is only on one side of the thin film part 3 and both sides are in contact with the porous part 4 (when the thin film part 3 is inside the porous part 4). The thin film portion 3 can more effectively absorb the cavity resonance sound and vibrate, thereby reducing the cavity resonance sound.
From the same viewpoint, it is more preferable to cover all of at least one of the side surfaces of the porous portion 4 as shown in FIG.

Here, the porous portion 4 is not particularly limited as long as it is a porous structure. For example, a foam (so-called sponge) having open cells in which rubber or a synthetic resin (for example, polyurethane) is foamed, and Including animal fibers, plant fibers, synthetic fibers or the like intertwined and connected together. When the “porous structure” is a foam, it is preferably an open cell, but also includes a cell having closed cells.
In addition, the porous part 4 can also be formed with one or more types of materials.

  In addition, from the viewpoint of efficiently absorbing the cavity resonance sound, the porous portion 4 is preferably formed of rubber or a synthetic resin (for example, an ether-based polyurethane such as polyether urethane), and more preferably 80 ° C. or higher. It is a synthetic resin having heat resistance.

Furthermore, the thin film portion 3 is not particularly limited as long as it is in the form of a film, but for example, a rubber or synthetic resin formed into a thin film, animal fibers, plant fibers, or synthetic fibers are closely intertwined and integrated. Includes connected and film-like materials. From the viewpoint of efficiently absorbing the cavity resonance sound, the thin film portion 3 is preferably formed of a synthetic resin such as rubber or polyethylene, more preferably a synthetic resin having a heat resistance of 80 ° C. or higher.
In addition, the thin film part 3 can also be formed with one or more types of materials.

Here, the sound absorbing member 1 having the thin film portion 3 and the porous portion 4 can be formed by an arbitrary method. However, the porous portion 4 is bonded at least partially using an adhesive or a double-sided tape. When the thin film portion 3 is attached to the surface, or when the thin film portion 3 is disposed inside the porous portion 4, both sides of the thin film portion 3 are sandwiched between the porous portions 4 and bonded to each other. 4 simply disposing the thin film portion 3 (for example, cutting the porous portion 4 and simply disposing the thin film portion 3 therein to seal the cut opening of the porous portion 4) ) Etc.
The thin film portion 3 is preferably attached to the porous portion 4 without applying tension to the thin film portion 3 (for example, the thin film portion is more than the area of the surface of the porous portion 4 to which the thin film portion 3 is attached). The area of 3 is slightly larger). However, wrinkles can be generated in the thin film portion as a result of stretching without applying tension.

By the way, the sound absorbing member 1 can be formed of a plurality of different materials.
Further, in the illustrated example, the sound absorbing member 1 can include a wireless tag, a sensor, and the like in order to detect the presence or absence of the sound absorbing member 1 and a state such as temperature from the outside of the tire 2.

Then, the pneumatic tire 2 of this embodiment is illustrated and demonstrated, referring drawings.
The tire 2 has the above-described sound absorbing member 1 and is partially omitted in illustration, but is disposed on the outer side in the tire radial direction of the carcass extending in a toroidal shape between the bead portions and the carcass of the tread portion. A belt and a tread rubber disposed on the outer side in the tire radial direction of the belt and forming a tread surface are provided. The internal reinforcement structure of the tire 2 can be the same as that of a general tire.
In addition, as a pneumatic tire, the tire for passenger cars can be mentioned especially. This is because the performance of the cavity resonance sound is normally not required for tires other than passenger car tires, such as heavy duty tires and motorcycle tires.

In the tire 2, the above-described sound absorbing member 1 is disposed in the lumen I of the tire 2. Specifically, the sound absorbing member 1 is arranged on the surface TS of the tire 2 on the inner cavity I side, and in the example shown in FIG. 1, four sound absorbing members 1 (partially omitted) are arranged apart from each other in the tire circumferential direction. It is installed. More specifically, the sound absorbing member 1 is disposed on the surface TS of the inner liner that forms the surface TS on the inner cavity I side of the tire 2, and the plurality of sound absorbing members 1 are arranged at substantially equal intervals with respect to the tire circumference. They are spaced apart in the direction.
Moreover, in the example shown in FIGS. 1 and 2, the sound absorbing member 1 has a rectangular parallelepiped shape, so that the largest surfaces 1 a and 1 b face in the tire circumferential direction, in other words, the surface is in the tire circumferential direction. They are arranged in an inclined posture (orthogonal in this example). When the sound absorbing member 1 has a rectangular parallelepiped shape, the surfaces 1a and 1b inclined in the tire circumferential direction do not have to be the largest surface of the rectangular parallelepiped. For example, as shown in FIG. 3, when the tire circumferential direction length l, the tire radial direction length d, and the tire width direction length w are set, the lengths l, d, and w are expressed as l>w> d. In addition, a thin film can be provided only on the inclined surfaces 1a and 1b in the tire circumferential direction.

Further, as shown in FIG. 1, the thin film portion 3 in the sound absorbing member 1 disposed in the lumen I of the tire 2 is at least partially inclined with respect to the tire circumferential direction, and the thin film portion 3. Covers at least a part of the surface of the porous portion 4. Further, at least a part of the thin film portion 3 is formed on a side surface of the sound absorbing member 1 located in the tire circumferential direction (the largest surfaces 1a and 1b facing in the tire circumferential direction in the drawing).
Specifically, in the illustrated example, as described above, the thin film portion 3 has a two-layer structure of the first thin film portion 31 and the second thin film portion 32, but the first thin film portion 31 is porous. The surface of the portion 4 that is inclined perpendicular to the tire circumferential direction is covered along the surface, and the second thin film portion 32 is inclined inside the porous portion 4 perpendicular to the tire circumferential direction. Are arranged. Therefore, in the illustrated example, the first thin film portion 31 and the second thin film portion 32 in the thin film portion 3 are inclined with respect to the tire circumferential direction, and the first thin film portion 31 is at least on the surface of the porous portion 4. A first thin film portion 31 is formed on the entire side surface 1 a that covers a part and is located on one side of the sound absorbing member 1 in the tire circumferential direction.
Note that “at least a part is inclined with respect to the tire circumferential direction” for the thin film part means that at least a part of the thin film part has a tire radial direction component.

Further, as shown in FIG. 2, the area of the thin film portion 3 included in one sound absorbing member 1 in the direction perpendicular to the tire circumferential direction is equal to the tire circumferential direction of the lumen I of the tire 2. It is 50% or more of the cross-sectional area in the vertical direction.
Specifically, in the illustrated example, the area of the porous portion 4 in the direction perpendicular to the tire circumferential direction is the breakage of the lumen I of the tire 2 in the direction perpendicular to the tire circumferential direction. The thin film portion 3 having an area equivalent to the area of the porous portion 4 is also 50% or more of the cross-sectional area of the lumen I of the tire 2. Further, in the illustrated example, the areas of the first thin film portion 31 and the second thin film portion 32 of the thin film portion 3 are 50% or more of the cross-sectional area of the lumen I of the tire 2, respectively.
The area of the thin film portion 3 may be smaller than the area of the porous portion 4 by providing the thin film portion 3 only on a part of the surface of the porous portion 4 that is inclined with respect to the tire circumferential direction. Alternatively, the porous part 4 in the case where the thin film part 3 protrudes from the porous part 4 or has one or more through holes (larger than the cell area of the porous part 4) in the tire circumferential direction, the tire The area of the thin film part 3 is larger than the area of the porous part 4 by covering with the thin film part 3 having the same area as the surface surrounded by the outer contour of the porous part 4 in the circumferential direction. Also good.

Here, the operation and effect of the pneumatic tire according to the embodiment of the present invention will be described.
In the pneumatic tire according to the embodiment of the present invention, the number of cells is 5 to 30 cells / 25 mm on a predetermined sound absorbing member 1, that is, the surface TS on the inner side of the tire 2, and 25%. Since the sound absorbing member 1 having the porous portion 4 having a hardness of 20 to 200 N is disposed, both weight reduction and reduction of cavity resonance sound can be achieved.

  Moreover, in this tire 2, as shown in FIG. 1, it is preferable that at least a part of the thin film portion 3 is inclined with respect to the tire circumferential direction. According to this configuration, the portion of the thin film portion 3 that is inclined with respect to the tire circumferential direction blocks the cavity resonance sound in the tire circumferential direction and effectively absorbs it, thereby effectively reducing the cavity resonance noise. Can do.

Moreover, in this tire 2, as shown in FIG. 1, it is preferable that the thin film part 3 covers at least a part of the surface of the porous part 4, preferably in a posture inclined with respect to the tire circumferential direction. According to this configuration, since the thin film portion 3 covers the surface of the porous portion 4, the thin film portion 3 located on the surface 1a of the sound absorbing member 1 is directly exposed to the cavity resonance sound. It is possible to effectively reduce the cavity resonance sound by blocking it in the tire circumferential direction.
From the same viewpoint, as shown in FIG. 1, all of the surface (side surface in the tire circumferential direction) of at least one side of the surface of the porous portion 4 that is inclined with respect to the tire circumferential direction is the thin film portion 3. Is more preferably covered with a posture inclined with respect to the tire circumferential direction. Further, from the viewpoint of efficiently reducing the cavity resonance sound by the sound absorbing member 1, the thin film portion 3 covers the surface of the porous portion 4 that is inclined with respect to the tire circumferential direction in a posture perpendicular to the tire circumferential direction. Is more preferable.

In the tire 2, as shown in FIG. 2, the area of the thin film portion 3 included in one sound absorbing member 1 in the direction perpendicular to the tire circumferential direction is the tire circumferential direction of the lumen I of the tire 2. Is preferably 50% or more, more preferably 80% or more of the cross-sectional area in a direction perpendicular to the vertical direction. According to this configuration, the sound absorbing member 1, particularly the thin film portion 3, can largely block the cavity resonance sound existing in the tire circumferential direction in the inner cavity I of the tire 2, and therefore the cavity resonance sound can be sufficiently reduced. can do.
In addition, from the viewpoint of reducing the cavity resonance sound, it is preferable that the area of the thin film portion 3 is large, but from the viewpoint of rim assembling property, it is preferably 90% or less.

Further, in the tire 2, as shown in FIG. 1, a plurality of sound absorbing members 1 are disposed on the surface TS on the inner cavity I side of the tire 2 so as to be spaced apart from each other in the tire circumferential direction. It is preferable that at least a part of the thin film portion 3 is formed on the side surface located in the tire circumferential direction. According to this configuration, since it is not necessary to dispose the sound absorbing member in the inner cavity I of the tire 2 with a large volume, the cavity resonance noise can be effectively reduced without increasing the weight.
From the same viewpoint, it is more preferable to dispose 2 to 8 sound absorbing members 1, and it is particularly preferable to dispose 4 sound absorbing members 1 as illustrated. When a plurality of sound absorbing members 1 are arranged, it is preferable to arrange them at equal intervals in the tire circumferential direction, but the intervals can also be arranged non-uniformly. Further, the arrangement can be determined in consideration of uniformity and the like.

  Further, from the viewpoint of sufficiently reducing the cavity resonance noise, the sound absorbing member 1 has the inner surfaces of the sidewall portions 5 on both sides of the tire 2 in the tire width direction in a cross-sectional view in a direction perpendicular to the tire circumferential direction. Preferably it has the same width as measured along. However, since the sidewall portion 5 is repeatedly bent in the tire radial direction by rolling of the tire 2, the sound absorbing member 1 is measured along the tire width direction from the inner surface of the sidewall portion 5 on both sides of the tire 2 by 10 mm. More preferably, the sound-absorbing member 1 has such a width as to be separated by a certain degree.

  By the way, the sound absorbing member 1 can be disposed on the surface TS on the inner cavity I side of the tire 2 by any method. For example, the sound absorbing member 1 having the thin film portion 3 and the porous portion 4 is provided. It can be attached using an adhesive or an adhesive tape. Moreover, a sealant layer and a hook-and-loop fastener are provided, and the sound absorbing member 1 can be disposed on the inner surface TS of the tire 2 through them. Furthermore, the sound absorbing member 1 is attached to, for example, an adhesive or the like on a fixing band that extends over one circumference of the surface TS of the tire 2 on the inner side of the lumen I, and the fixing band to which the sound absorbing member 1 is attached By attaching on the surface TS on the side, the sound absorbing member 1 can be disposed on the inner surface TS of the tire 2 via a fixed band. The fixing band can be attached to and detached from the inner surface TS of the tire 2 by using an adhesive or the like, or by using the fixing band as an elastic body and restoring force of the fixing band. By attaching, thereby, the sound absorbing member 1 can be detachably fixed on the inner surface TS of the tire 2 and attached.

Further, the position on the surface TS on the inner cavity I side of the tire 2 where the sound absorbing member 1 is disposed can be arbitrarily set. As shown in FIG. 2, the sound absorbing member 1 can be positioned on the surface TS on the inner side I of the tire 2 corresponding to the tread surface, but the imaginary line extends in the tire radial direction through the tread grounding end of the tread surface. It is also possible to position the imaginary line on the outer side in the tire width direction, or to position without straddling (for example, on the inner surface TS of the tire 2 corresponding to the sidewall portion 5 or the shoulder portion). it can.
The sound absorbing member 1 is disposed at a position where the tire 2 is in contact with a tread pattern formed on the tread surface, a tire surface protecting or heat radiating projection or the like which can be formed on the surface of the sidewall portion 5. It can be arbitrarily positioned on the inner surface TS. However, the sound absorbing member 1 tends to store heat while the tire 2 is rolling, and the arrangement position of the sound absorbing member 1 may be determined from the viewpoint of reducing the heat stored in the sound absorbing member 1 from being transferred to the tire member. it can. When the sound absorbing member 1 is located on the inner surface TS of the tire 2 corresponding to the tread surface, a groove is formed at a position on the tread surface corresponding to the arrangement position of the sound absorbing member 1 in order to promote heat dissipation. Preferably it is.

  Furthermore, the arrangement position of the sound absorbing member 1 can be arbitrarily positioned on the inner surface TS of the tire 2 with respect to, for example, the arrangement position of the belt inside the tire 2. However, a position corresponding to the position of the end of a belt (for example, an inclined belt layer or a belt reinforcing layer) on the tire 2 (a virtual line extending in the tire radial direction passing through the end and the inner surface TS of the tire 2 intersects). Position). When the temperature near the end of the belt layer rises, separation or the like may occur at the end, so that the durability of the tire can be improved by separating the sound absorbing member 1 that tends to store heat from the end of the belt layer. Can be improved.

  Here, a modified example of the sound absorbing member 1 and the tire 2 of the present embodiment will be described with reference to FIG. In addition, in the modified example of the sound absorbing member 1 and the tire 2, the description of the same configuration as the sound absorbing member 1 described with reference to FIGS.

The sound absorbing member 1 shown in FIG. 1 is formed of a rectangular parallelepiped porous portion 4 and a thin film portion 3 and is a rectangular parallelepiped as a whole, whereas the sound absorbing member 1 shown in FIG. It is configured as follows. That is, the porous portion 4 of the sound-absorbing member 1 shown in FIG. 4 includes an extending portion 41 extending in an arc shape (circular shape in the drawing), and a radially inner side of the extending portion 41 in the arc (circle). A plurality of rectangular parallelepiped protrusions 42 are provided on the surface. Moreover, the thin film part 3 covers the surface which inclines with respect to the circumferential direction of the extension part 41 among the surfaces of the protrusion part 42 of the said porous part 4, The 1st thin film inclined perpendicularly | vertically with respect to the said circumferential direction It has a two-layer structure having a portion 31 and a second thin film portion 32 inclined perpendicularly to the circumferential direction inside the protruding portion 42 of the porous portion 4. Therefore, the first thin film portion 31 and the second thin film portion 32 in the thin film portion 3 are inclined with respect to the circumferential direction, and the first thin film portion 31 covers at least a part of the surface of the porous portion 4. .
As shown in the figure, in the example of the tire 2 in which the sound absorbing member 1 is disposed on the inner surface TS of the tire 2, the extending portion 41 of the porous portion 4 extends in the tire circumferential direction and has an arc (circle). ) In the radial direction outer side is the inner surface TS side of the tire 2, and the circumferential direction of the extending portion 41 is the tire circumferential direction of the tire 2.

  In addition, although the extending part 41 extends over one circumference of the inner surface TS of the tire 2, it may extend over a part of the inner surface TS of the tire 2.

  Thus, in the modified example of the sound absorbing member 1 and the pneumatic tire 2, the sound absorbing member 1 includes the porous portion 4 having the extending portion 41 and the protruding portion 42, and the thin film portion 3, so that FIG. The cavity resonance noise can be further reduced as compared with the sound absorbing member 1 and the pneumatic tire 2 shown.

  Next, an example in which the above-described sound absorbing member 1 is disposed on the surface RS of the rim R of the assembly of the pneumatic tire 2 and the rim R will be described with reference to FIG. In this example of the assembly, the sound absorbing member 1 described with reference to FIGS. 1 to 4 can be used.

In the example shown in FIGS. 1 and 2, the sound absorbing member 1 is disposed on the surface TS on the inner cavity I side of the tire 2, whereas in the example of the assembly, the sound absorbing member 1 is disposed inside the tire 2. The cavity I is disposed on the surface RS of the rim R on which the tire 2 is mounted.
Specifically, in the example of the assembly shown in FIG. 5, the rectangular parallelepiped sound absorbing member 1 shown in FIG. 1 is disposed on the surface RS of the rim R on the inner cavity I side of the tire 2. The sound absorbing member 1 can be disposed on the surface RS of the rim R in the same manner as the sound absorbing member 1 is disposed on the inner surface TS of the tire 2.
Further, although not shown in the drawings, in another example of the assembly, the sound absorbing member 1 including the porous portion 4 having the extending portion 41 and the protruding portion 42 and the thin film portion 3 shown in FIG. It is disposed on the surface RS. Specifically, in the example illustrated in FIG. 4, the protrusion 42 is disposed on the extending portion 41 on the radially inner surface of the extending portion 41, and the radially outer surface of the extending portion 41 is The sound absorbing member 1 is disposed on the inner surface TS of the tire 2 with the inner surface TS of the tire 2 facing upward. On the other hand, in another example of this assembly, the protrusion 42 is disposed on the extending portion 41 on the radially outer surface, and the radially inner surface of the extending portion 41 is the rim R. The sound absorbing member 1 is disposed on the surface RS of the rim R in a state of facing the surface RS side.

  Thus, in the above example of the assembly, since the sound absorbing member 1 is disposed on the surface RS of the rim R, it is possible to avoid a concern that the sound absorbing member 3 stores the heat generated by the tire 1.

  As mentioned above, although embodiment of this invention was described with reference to drawings, the sound absorption member and pneumatic tire of this invention are not limited to said example, A change can be added suitably to this invention. it can. For example, in the example shown in FIGS. 1 to 5, the thin film portion of the sound absorbing member is perpendicular to the tire circumferential direction, but the thin film portion is used together with the porous portion or only the thin film portion with respect to the tire circumferential direction. It is also possible to make the posture inclined to less than degrees. Moreover, in the example shown in FIGS. 1-5, although the thin film part does not cover the tire width direction side surface and tire circumferential direction side surface of a porous part, it can also cover.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.
The tires of the examples according to the embodiment of the present invention and the tires of the comparative examples were made as prototypes, and the following experiments 1 and 2 were performed.

[Experiment 1]
The tire of Example 1 has a tire size of 205 / 55R16, and has four rectangular parallelepiped sound absorbing members arranged at equal intervals in the tire circumferential direction on the inner surface of the tire as shown in FIG. It is. Each sound-absorbing member is composed of a rectangular parallelepiped polyurethane porous portion having a thickness of 30 mm, 18 cells / 25 mm, and 25% hardness of 70 N, and a polyethylene thin film portion having a thickness of 10 μm. ing. The thin film portion is a single layer and covers the entire side surface in the direction perpendicular to the tire circumferential direction on one side in the tire circumferential direction of the rectangular parallelepiped porous portion. 80% of the cross-sectional area.
In Example 2, the thickness of the porous portion of the tire of Example 1 was changed to 50 mm, and one thin film portion was added to the inside of the sound absorbing member (measured from the side surface of the porous portion covered with the thin film portion). The tire is the same as the tire of Example 1 except that an additional thin film portion is disposed at a distance of 30 mm and the thin film portion has two layers as shown in FIG.
The tire of Comparative Example 1 is the same as the tire of Example 1 except that the sound absorbing member of Example 1 is not provided.
The tire of Comparative Example 2 is the same as the tire of Example 1 except that the sound absorbing member of Example 1 is changed to a sound absorbing member having no thin film part (that is, the thin film part is removed from the sound absorbing member of Example 1). is there.
The tire of Comparative Example 3 is the same as the tire of Example 1 except that the porous portion of the sound absorbing member of Example 1 is changed to one having a cell number of 50/25 mm and a 25% hardness of 500 N.

The performance (weight reduction, reduction of cavity resonance noise) of each test tire was evaluated by the following method.
[Weight saving]
The sound absorbing member was removed from each of the above test tires, and each mass (g) was measured and evaluated.
[Reduction of cavity resonance]
Each of the above test tires was mounted on a rim having a size of 16 × 6.5J, filled with air so that the internal pressure was 250 kPa, and the tire was provided with an iron drum having a steel plate surface with a diameter of 1.7 m. Attached to a replica drum tester, cavity resonance was measured. In the measurement method, each test tire is rolled at a constant speed under conditions of a tire load mass of 5.0 kN and a speed of 60 km / h in the test machine, and a vertical tire axial force (Fz) is measured using a wheel force meter. ) From the frequency spectrum obtained by measuring the peak value of the frequency corresponding to the cavity resonance. A cavity resonance reduction amount (dB), which is a reduction amount of the peak value of cavity resonance generated in the tires of Examples 1 and 2 and Comparative Examples 2 and 3 from the peak value of cavity resonance generated in the tire of Comparative Example 1. Table 1 shows. A larger value means that the cavity resonance is lower than the sound volume generated in the tire of Comparative Example 1.

  From Table 1, it can be seen that the sound absorbing members and tires of Examples 1 and 2 reduce the cavity resonance noise while being lighter than the sound absorbing members and tires of Comparative Examples 1 to 3.

[Experiment 2]
The tire of Example 3 has a tire size of 205 / 55R16, and, as shown in FIGS. 6 and 7, a porous portion that extends on the inner surface of the tire and extends around the inner surface of the tire, A thin film portion covering the entire circumference of the surface of the porous portion on the tire lumen I side (the thin film portion is not inclined in the tire circumferential direction and is perpendicular to the tire radial direction of the porous portion as shown in FIG. The sound absorbing member is disposed only on the surface. The sound-absorbing member is 30 mm in thickness (measured in the tire radial direction), 18/25 mm in number of cells, and a porous portion made of a circular polyurethane having a 25% hardness of 70 N and a polyethylene having a thickness of 10 μm. It consists of a thin film part.
The tire of Comparative Example 4 is the same as the tire of Example 3 except that the sound-absorbing member of Example 3 is changed to one having 50 cells / 25 mm and 25% hardness of 500 N.
The performance (weight reduction, reduction of cavity resonance noise) of each of the above test tires was evaluated by the above method.

  From Table 2, it can be seen that the sound absorbing member and tire of Example 3 are lighter than the sound absorbing member and tire of Comparative Example 4 while reducing cavity resonance noise.

  According to the present invention, it is possible to provide a sound absorbing member and a pneumatic tire that can achieve both weight reduction and reduction of cavity resonance noise.

1: sound absorbing member 1a, 2b: surface of sound absorbing member 2: pneumatic tire (tire)
3: Thin film part 31: First thin film part 32: Second thin film part 4: Porous part 41: Extension part 42: Protruding part 5: Side wall part C: Tire equatorial plane I: Lumen TS: Lumen of tire Side surface (inner surface of tire)
R: Rim RS: Rim surface

Claims (7)

A sound-absorbing member disposed in the inner cavity of the tire,
The sound absorbing member has a thin film portion and a porous portion having a cell number of 5 to 30 cells / 25 mm and a 25% hardness of 20 to 200 N.   The sound absorbing member according to claim 1, wherein the thin film portion covers at least a part of a surface of the porous portion.   The sound absorbing member according to claim 1 or 2, wherein the porous portion has a thickness of 10 to 50 mm.   The sound absorbing member according to claim 1, wherein the thin film portion has a thickness of 5 to 30 μm.   A pneumatic tire, wherein the sound absorbing member according to any one of claims 1 to 4 is disposed on a surface on a lumen side of the tire. A plurality of the sound absorbing members are spaced apart from each other in the tire circumferential direction on the inner surface of the tire,
The pneumatic tire according to claim 5, wherein at least a part of the thin film portion is formed on a side surface of the sound absorbing member located in the tire circumferential direction.   The area of the thin film portion included in one sound absorbing member in the direction perpendicular to the tire circumferential direction is 50% or more of the cross-sectional area of the tire lumen in the direction perpendicular to the tire circumferential direction. The pneumatic tire according to claim 5 or 6, wherein there is a pneumatic tire.

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