JP2019051935A - tire - Google Patents

Abstract

To provide a tire that can acquire acoustic absorption effect for cavernous resonance for a long time by suppressing heat generation and deterioration in an acoustic absorption material due to use.SOLUTION: A tire 10 is arranged with an acoustic absorption material 1 at a tire inner cavity surface F. The acoustic absorption material 1 is encapsulated in a sheet 2 and forms an acoustic absorption member 3. The acoustic absorption member 3 is attached to the tire inner cavity surface F, accordingly, the acoustic absorption material 1 is disposed at the tire inner cavity surface F without being bonded to other members. The acoustic absorption material is a nonwoven fabric containing inorganic fibers.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire, and more particularly to an improvement in technology for reducing cavity resonance noise of a pneumatic tire.

  Generally, in a pneumatic tire mounted on a rim and attached to a vehicle, the surface of the tread portion is in contact with a step on the road surface and vibrates while the vehicle is running, so that it is formed by air filled in the tire lumen. Cavity resonance occurs due to the air column. This cavity resonance is a main cause of so-called road noise, and the resonance frequency thereof is, for example, about 200 Hz, and many exist in the range of 180 to 300 Hz. When road noise is transmitted to the passenger compartment, it is sharp and has a high peak value, unlike noise in other frequency bands, and it is annoying noise for passengers in the passenger compartment. .

  In order to reduce the road noise by suppressing the cavity resonance of such a tire, there is a technology for reducing the noise by arranging a member having a sound absorbing property on the tire inner surface and absorbing the cavity resonance sound by this member. Are known. For example, in Patent Document 1, a pneumatic structure in which a sound damper made of an inorganic fiber porous material in which inorganic fibers are entangled is arranged in a tire lumen formed by a rim and a pneumatic tire attached to the rim. A tire and rim assembly is disclosed.

Japanese Patent Laying-Open No. 2005-1428 (Claims, FIG. 5)

  When a non-woven fabric made of organic fibers is used as the sound-absorbing member, there is a problem that the thickness is reduced due to deformation due to thermal deterioration. In contrast, non-woven fabrics made of inorganic fibers such as rock wool and glass wool are superior in heat resistance compared to organic fibers and have the advantage of preventing thermal degradation due to high-speed running.

  However, when such an inorganic fiber is directly installed on the tire cavity surface, the elasticity of the fiber is small, so that the fiber is destroyed by the deformation of the tire on the contact surface, and there is a problem that the sound absorption is likely to be lowered. In particular, when a non-woven fabric made of inorganic fibers is directly attached to a tire, there are cases where a large number of inorganic fibers are broken inside the non-woven fabric due to deformation of the tire and cannot function as a non-woven fabric.

  Accordingly, an object of the present invention is to provide a tire capable of obtaining a sound absorbing effect of cavity resonance sound over a long period of time by suppressing heat generation and deterioration of the sound absorbing material accompanying use.

  As a result of intensive studies, the present inventor has found that the above problem can be solved by using a method of attaching the sound absorbing material to the tire cavity surface using a sheet, and has completed the present invention.

That is, the tire of the present invention is a tire in which a sound absorbing material is disposed on the tire lumen surface,
The sound-absorbing material is encapsulated in a sheet to form a sound-absorbing member, and the sound-absorbing member is attached to the tire lumen surface so that the sound-absorbing material is not bonded to other members. The sound-absorbing material is a non-woven fabric containing inorganic fibers.

  In the tire of the present invention, it is preferable that the sheet has liquid permeability.

  Moreover, it is also preferable that the said sheet | seat has an aperture part and the average aperture diameter of this aperture part is smaller than the average fiber diameter of the fiber which comprises the said nonwoven fabric. Further, the melting point of the sheet is preferably 180 ° C. or higher.

  According to the present invention, with the above-described configuration, it is possible to suppress the heat generation and deterioration of the sound absorbing material that accompanies use, and to realize a tire that can obtain the sound absorption effect of cavity resonance sound over a long period of time. became.

It is a width direction sectional view showing an example of the tire of the present invention. It is sectional drawing of the width direction which shows the other example of the tire of this invention. It is width direction sectional drawing which shows the other example of the sound-absorbing material which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The present invention relates to an improvement in a tire in which a sound-absorbing material is disposed on a tire lumen surface. 1 and 2 are sectional views in the width direction of an example of the tire of the present invention. The illustrated tires 10 and 20 include a pair of bead portions 21, a pair of sidewall portions 22 extending outward in the tire radial direction, and a tread portion 23 extending between both sidewall portions 22. Become. The illustrated tires 10 and 20 have a skeleton of one or more carcass plies 25 extending in a toroid shape between a pair of bead cores 24 embedded in both bead portions 21, and a crown portion of the carcass ply 25. One or more, in the illustrated example, two inclined belt layers 26 are provided on the outer side in the tire radial direction.

  As shown in FIG. 1, in the tire 10 according to the first embodiment of the present invention, a sound absorbing material 1 is encapsulated in a sheet 2 to form a sound absorbing member 3, and the sound absorbing member 3 is a tire lumen. By being attached to the surface F, the sound absorbing material 1 is arranged on the tire lumen surface F without being bonded to other members. Here, the tire lumen surface means a surface formed by the tire inner surface and the rim.

  In other words, in the present invention, the sound-absorbing material 1 having sound-absorbing properties is attached not directly to the tire cavity surface F but via the seat 2, in other words, the sound-absorbing material 1 is bonded to any other member. Instead, it is arranged on the tire cavity surface F in a state where it is only in contact. As a result, even when the tire is deformed, the deformation is not directly transmitted to the sound absorbing material 1. Therefore, even when the sound absorbing material 1 made of a low elastic material such as an inorganic fiber is used, the sound absorbing material 1 There will be no damage or deterioration. On the other hand, since the sound absorbing material 1 is fixed to the tire cavity surface F by the seat 2, the sound absorbing material 1 does not move inside the tire and can appropriately obtain the sound absorbing effect of the cavity resonance sound. It is.

As shown in FIG. 2, in the tire 20 according to the second embodiment of the present invention, the sound absorbing material 1 is a tire lumen surface from the inner side in the tire radial direction by a seat 2 attached to the tire lumen surface F. By being pressed against F, it is arranged on the tire lumen surface F without being directly attached to the tire lumen surface F.

  Also in this case, the sound-absorbing material 1 having sound-absorbing properties is attached to the tire cavity surface F using the seat 2 instead of directly. In other words, the sound-absorbing material 1 is not bonded to any other member. , It is arranged on the tire cavity surface F only in contact. As a result, even when the tire is deformed, the deformation is not directly transmitted to the sound absorbing material 1. Therefore, even when the sound absorbing material 1 made of a low elastic material such as an inorganic fiber is used, the sound absorbing material 1 There will be no damage or deterioration. On the other hand, since the sound absorbing material 1 is fixed to the tire cavity surface F by the seat 2, the sound absorbing material 1 does not move inside the tire and can appropriately obtain the sound absorbing effect of the cavity resonance sound. It is.

  In the present invention, the sound-absorbing material 1 having a sound-absorbing property is not directly attached to the tire cavity surface F, but is only in contact with the sound-absorbing material 1, and the movement of the sound-absorbing material 1 is restricted. The seat 2 may be used as long as it is disposed on the tire cavity surface F, whereby the desired effect of the present invention can be obtained.

  As the sound-absorbing material 1 used in the present invention, any material may be used as long as it is a material conventionally used for absorbing the cavity resonance sound of a tire. Specific examples include nonwoven fabrics, sponges, and other porous materials made of organic fibers and inorganic fibers. Here, the non-woven fabric means a material in which fibers are combined without being woven, and the production method and the types of fibers are not limited. The sponge means a so-called porous structure, and includes, for example, a so-called natural sponge of animal or vegetable nature in addition to a so-called synthetic sponge formed by foaming rubber or synthetic resin.

  Examples of fibers used in the nonwoven fabric include rayon, polyethylene terephthalate, polyethylene naphthalate, polybenzimidazole, polyphenylene sulfide, polyvinyl alcohol, aliphatic polyamide, aromatic polyamide (aramid), aromatic polyimide, and the like. Examples of the inorganic fiber include carbon fiber, fluorine fiber, glass fiber, and metal fiber, and examples of the unemployed cloth made of inorganic fiber include rock wool and glass wool. The length and thickness of the fibers constituting the nonwoven fabric can be arbitrarily set, and different types of fibers may be mixed to form the nonwoven fabric, or the nonwoven fabric may be formed using hollow filaments. It is. Among them, in the present invention, it is useful when the sound absorbing material is a non-woven fabric containing inorganic fibers because an effect that heat deterioration or the like hardly occurs even if the sound absorbing material is made of a low elastic material. is there.

により定義したとき、多孔度Φが０．９５以上であり、繊維間の平均距離ｄが０．５０δ〜４．００δの範囲内であることが好ましい。このような不織布を用いることで、タイヤ重量の増加を抑制し、かつ、吸音材の体積増加を抑制しつつ、空洞共鳴を効果的に抑制することが可能となる。繊維間の平均距離ｄが０．５０δ未満の場合には、繊維周辺の吸音を効果的に発揮する領域が過剰に重なってしまい、繊維自体が占有する体積が大きくなって、かえって吸音効果が低下してしまう。一方、繊維間の平均距離ｄが４．００δを超える場合には、前記繊維周辺の吸音を効果的に発揮する範囲ではない領域が増加し過ぎるため、吸音効果が低下してしまう。また、不織布の多孔度Φが０．９５以上であることから、空洞共鳴音の原因となる振動エネルギを有する音波が不織布に有効に透過し、不織布がかかる振動エネルギを充分に吸収して、気体の空洞共鳴に起因するロードノイズを低減することが可能となる。なお、ここでいう「繊維周りの充填気体の表皮厚さ」とは、空洞共鳴した振動エネルギを有する気体が不織布を構成する繊維に接触した際に、かかる気体がニュートンの粘性法則により繊維周りにトラップされ、振動エネルギが吸収される繊維周りの領域の主たる部分をいうものとする。また、ここでいう「気体」とは、空気、窒素ガス等の不活性ガスなど、一般にタイヤに充填されるものをいう。 Further, as the nonwoven fabric used for the sound absorbing material 1, the density of the gas filled in the tire is ρ _a (kg / m ³ ), and the cavity resonance of the filling gas in the tire lumen when the tire and rim assembly is unloaded. Is the natural natural frequency ω (rad / s), the viscosity coefficient of the filling gas is η (Pa · s), the density of the nonwoven fabric is ρ _b (kg / m ³ ), and the density of the fibers constituting the nonwoven fabric is ρ _f (Kg / m ³ ), where the average cross-sectional radius of the fibers constituting the nonwoven fabric is r (μm), the skin thickness δ (μm) of the filling gas around the fibers, the average distance d (μm) between the fibers, and the porosity of the nonwoven fabric Degree Φ (−) is expressed by the following formulas (1) to (3),

It is preferable that the porosity Φ is 0.95 or more and the average distance d between the fibers is in the range of 0.50δ to 4.00δ. By using such a nonwoven fabric, it is possible to effectively suppress cavity resonance while suppressing an increase in tire weight and an increase in volume of the sound absorbing material. When the average distance d between the fibers is less than 0.50δ, the area that effectively absorbs the sound around the fibers is excessively overlapped, and the volume occupied by the fibers itself is increased, and the sound absorbing effect is reduced. Resulting in. On the other hand, when the average distance d between the fibers exceeds 4.00 δ, since the area outside the range where the sound absorption around the fibers is effectively exhibited increases too much, the sound absorbing effect is lowered. Further, since the porosity Φ of the nonwoven fabric is 0.95 or more, the sound wave having vibration energy that causes the cavity resonance sound is effectively transmitted to the nonwoven fabric, and the nonwoven fabric sufficiently absorbs the vibration energy applied to the gas. It becomes possible to reduce road noise caused by cavity resonance. The “skin thickness of the filling gas around the fiber” as used herein means that when a gas having vibration energy that resonates with the cavity comes into contact with the fiber constituting the nonwoven fabric, the gas is placed around the fiber by Newton's law of viscosity. The main part of the area around the fiber that is trapped and absorbs vibrational energy. In addition, “gas” as used herein refers to what is generally filled in a tire, such as air or an inert gas such as nitrogen gas.

  Specific examples of the sponge include polyurethane foam, foamed silicone, foamed rubber, foamed polypropylene, and polystyrene foam.

  As the material of the sound absorbing material 1, it is preferable to use a material having a glass transition temperature of 90 ° C. or higher, for example, 90 to 300 ° C. By increasing the thermal stability of the sound absorbing material 1 itself, it is possible to more effectively suppress a decrease in the thickness of the sound absorbing material 1 in the tire radial direction during traveling.

  In addition, the sound-absorbing material 1 can be used by laminating a plurality of types of different materials in two or more layers, for example, 2 to 8 layers in the tire radial direction.

  The sound absorbing material 1 in the example shown in FIGS. 1 and 2 has a rectangular cross-sectional shape, but the cross-sectional shape of the sound absorbing material is not limited to this, and may be a trapezoid or the like in addition to a quadrangle such as a rectangle. In addition, as shown in FIG. 3, the cross-sectional shape in a cross section perpendicular to the longitudinal direction has two peak portions 11 having a large thickness, and a valley portion having a small thickness provided between the two peak portions 11. 12 can also be used. In this case, the skirt side of the peak portion 11 is the side disposed on the tire lumen surface. Furthermore, it is also possible to increase the surface area by providing an uneven shape on the surface of the sound absorbing material or by providing grooves. By appropriately changing the shape of the sound absorbing material and increasing its surface area, the effect of suppressing cavity resonance can be further enhanced, and the effect of suppressing heat deterioration can be obtained by improving heat dissipation.

  As the sheet 2 used in the present invention, as long as the sound absorbing material 1 can be encapsulated or pressed and fixed to the tire cavity surface F, the material, structure, and the like are not particularly limited. Specifically, for example, a mesh-like sheet made of a synthetic resin such as polyester, nylon, Teflon (registered trademark), or polypropylene can be suitably used. As such a mesh sheet, for example, a sheet having an opening of 1 to 4000 μm can be used.

  As the sheet 2, it is preferable to use a sheet having a melting point of 180 ° C. or higher, for example, 180 to 400 ° C. Use of the sheet 2 having a melting point of 180 ° C. or higher is preferable because the sheet itself has heat resistance, so that the thermal stability and durability of the sound absorbing material can be further improved.

  Further, as the sheet 2, it is preferable to use a sheet having liquid permeability. By using the sheet 2 having liquid permeability, the puncture repair liquid can permeate the sheet 2 when the tire is punctured, which makes it possible to repair the puncture in the portion where the sound absorbing material 1 is disposed.

  Furthermore, when using a nonwoven fabric as the sound absorbing material 1 and using a sheet 2 having an aperture, the average aperture diameter of the aperture of the sheet 2 is larger than the average fiber diameter of the fibers constituting the nonwoven fabric. Small is preferable. If the sheet 2 has an aperture, the liquid permeability can be ensured. However, if the diameter of the aperture is too large, the nonwoven fabric fibers constituting the sound absorbing material 1 may fall off the sheet 2. is there. By setting the average aperture diameter of the aperture portion of the sheet 2 to be smaller than the average fiber diameter of the fibers constituting the nonwoven fabric, the sound absorbing material 1 is reliably arranged on the tire lumen surface F by the sheet 2, It is possible to prevent the fibers from dropping and to repair the puncture with the puncture repair liquid.

  In the present invention, the sound absorbing material may be disposed in any part of the tire lumen surface F. In the illustrated example, the sound absorbing material is disposed on the tire inner surface of the tread portion 23 in the tire lumen surface F, but may be disposed on the tire inner surface of the sidewall portion 22, for example. Further, it is also possible to arrange the tires close to the shoulder side of the tread portion 23 so as to cross a tire radial direction line passing through the ground contact end TE of the tread portion 23.

  Further, the sound absorbing material can be continuously arranged over the entire circumference in the tire circumferential direction, and even if one long sound absorbing material is used, a plurality of sound absorbing materials divided in the tire circumferential direction are used. May be. In this case, in the embodiment shown in FIG. 1, one long sound absorbing material is encapsulated by a sheet, or a plurality of sound absorbing materials are collectively or individually encapsulated by a sheet, What is necessary is just to arrange | position continuously in a tire peripheral direction. In the embodiment shown in FIG. 2, one sound absorbing material or a plurality of sound absorbing materials are continuously pressed in the tire circumferential direction while being pressed by a sheet and continuously arranged in the tire circumferential direction. That's fine. Furthermore, the sound absorbing material can be arranged in a spiral shape in the tire circumferential direction by the same method as described above.

  Here, the sound absorbing material may be formed in an annular shape by abutting the end faces of the long sound absorbing material arranged along the tire circumferential direction. This abutting surface can take various configurations. For example, the abutment surface can be substantially flat, can be parallel to a reference plane that forms part of the tire meridian cross section including the tire rotation axis, and is inclined relative to the reference plane. It can also be assumed. Furthermore, you may form the discontinuous part in which the sound-absorbing material is not arrange | positioned in a part of the tire circumferential direction, without abutting the end surface of the elongate sound-absorbing material arrange | positioned along the tire circumferential direction.

  In the present invention, the tread pattern formed on the tread portion of the tread portion 23 is not particularly limited, but the location of the sound absorbing material can also be set in relation to the tread pattern. For example, since the sound absorbing material tends to store heat, the position of the sound absorbing material can be considered so that heat is not transmitted to the tire member. Specifically, for example, it is preferable to provide the sound absorbing material and the groove at positions corresponding to each other. Thereby, the heat accumulated in the sound absorbing material can be radiated from the groove.

In the present invention, the sound-absorbing material can also be disposed away from the inclined belt layer 26 or a position corresponding to the end of the belt reinforcing layer (not shown) in the tire width direction. At these ends, separation or the like is likely to occur due to heat storage. Therefore, the durability can be further improved by separating the sound absorbing material from these ends.

  In the present invention, the sound absorbing material is attached to the tire cavity surface using a sheet. The seat can be attached to the tire lumen surface in the present invention using, for example, an adhesive. In particular, when affixing to the tire inner surface, it is possible to affix after partially buffing the inner liner layer.

  Further, the sheet can be attached to the tire cavity surface via a sealant layer. As the sealant liquid for forming the sealant layer, any sticky fluid can be used. For example, a conventionally known sealant for puncture sealing can be used. For example, a silicone compound, a styrene compound, a urethane compound, an ethylene compound, or a gel sheet mainly composed of polybutene and a terpene resin can be used.

  Further, the seat can be attached to the tire lumen surface via a hook-and-loop fastener, and the seat can be attached to the fixing band member and attached to the tire lumen surface by the band member. When the band member is used, the seat may be fixed to the band member, and the band member may be attached to the tire lumen surface. The sheet is fixed to the band member, and the seat is connected to the band member from the tire inner peripheral surface side. May be attached so as to be pressed against the tire lumen surface. In any case, the band member can be fixed to the seat with an adhesive or the like, and both ends in the longitudinal direction can be connected to each other so that the seat can be attached to the tire cavity surface. At this time, the band member and the tire lumen surface may be bonded, or the band member may be formed of an elastic body, and may be elastically detachably attached without bonding. Furthermore, the sheet may be attached to the tire lumen surface via an adhesive tape.

  Furthermore, in the present invention, a wireless tag, a sensor or the like can be attached to the sheet surface.

  In the tire of the present invention, only the point that the sound absorbing material is disposed on the tire inner surface is important, whereby the desired effect of the present invention can be obtained, and The details of the tire structure and the material of each member are not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to examples.
As the sound absorbing material, glass wool having a width of 150 mm, a thickness of 25 mm, and a fiber diameter of 8 μm was used. As the sheet, a commercially available polyester mesh sheet PET6-HD (mesh size 6 μm, melting point 260 ° C., manufactured by Semitec Co., Ltd.) was used. A sound-absorbing material wrapped in a mesh sheet was affixed to the inner surface of the tread portion of a tire having a tire size of 255 / 35R20 with a width of 150 mm and a thickness of 25 mm along the circumferential direction of the tire with a double-sided tape. .

  When the obtained test tire was assembled on a rim having a rim size of 20 × 8.5 J and a high-speed running test was conducted, there was no decrease in sound absorption before and after running. Further, after unraveling the test tire, the sound absorbing material in the seat attached to the tire cavity surface was confirmed. As a result, the glass wool was not destroyed and maintained the same thickness as before the test. As a result, the sound absorbing material can be attached to the tire cavity surface using a sheet rather than directly, thereby suppressing thermal deterioration of the sound absorbing material associated with use and maintaining the sound absorption effect of the cavity resonance sound over a long period of time. Was confirmed.

DESCRIPTION OF SYMBOLS 1 Sound-absorbing material 2 Sheet | seat 3 Sound-absorbing member 10,20 Tire 11 Peak part 12 Valley part 21 Bead part 22 Side wall part 23 Tread part 24 Bead core 25 Carcass ply 26 Inclined belt layer F Tire lumen surface

Claims (4)

A tire in which a sound-absorbing material is disposed on the tire lumen surface,
The sound-absorbing material is encapsulated in a sheet to form a sound-absorbing member, and the sound-absorbing member is attached to the tire lumen surface so that the sound-absorbing material is not bonded to other members. The sound absorbing material is a non-woven fabric containing inorganic fibers.   The tire according to claim 1, wherein the sheet has liquid permeability.   The tire according to claim 1 or 2, wherein the sheet has an aperture portion, and an average aperture diameter of the aperture portion is smaller than an average fiber diameter of fibers constituting the nonwoven fabric. The tire according to any one of claims 1 to 3, wherein the sheet has a melting point of 180 ° C or higher.

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