pneumatic tires

Abstract

To provide a tire that can improve the overall performance of the sound-absorbing layer's durability and its ability to suppress the absorption of puncture repair fluid. [Solution] A pneumatic tire comprising an inner liner and a sound-absorbing layer disposed on the inner surface of the tire formed by the inner liner, wherein the sound-absorbing layer includes a sound-absorbing member and an adhesive member, and the density D of the sound-absorbing member c 50 kg / m 3 The above is true, and the thickness of the inner liner is T i (mm), the maximum thickness of the sound-absorbing layer is T c If (mm), then D c ×(T c / T i Pneumatic tires with a voltage of less than 7500.

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] Conventionally, in order to suppress the running noise of pneumatic tires, a pneumatic tire has been proposed in which a sound-absorbing material formed in a ring shape by a porous material is fixed to the inner peripheral surface of the tire (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a method for repairing a punctured pneumatic tire, a method of filling a tire inner cavity with a puncture repair liquid for filling a puncture hole is known. In such a repair method, in order to allow the repair liquid to penetrate into the puncture hole, it is necessary to position the puncture hole downward (ground side) prior to filling the puncture repair liquid. However, when the puncture repair liquid is filled into the pneumatic tire of Patent Document 1, the sound-absorbing material near the puncture hole may absorb the puncture repair liquid more than necessary. In that case, even if the pneumatic tire is rotated after filling the puncture repair liquid, the puncture repair liquid does not uniformly distribute in the tire circumferential direction, so there is a concern that the uniformity of the pneumatic tire after puncture repair deteriorates and the running noise increases (here, the “uniformity” refers to the uniformity of the weight including the pneumatic tire, the sound-absorbing material, and the puncture repair liquid).

[0005] In addition, the inner liner repeatedly deforms during tire running. Therefore, in order to prevent damage to the sound-absorbing material, etc., the sound-absorbing material is required to have a performance of deforming flexibly following the deformation of the inner liner.

[0006] An object of the present invention is to provide a tire capable of improving the overall performance of the durability performance of a sound absorption layer and the absorption suppression performance of a puncture repair liquid.

Means for Solving the Problems

[0007] The present invention is a pneumatic tire including an inner liner and a sound absorption layer disposed on the inner cavity surface of the tire formed by the inner liner. The sound absorption layer includes a sound absorption member and an adhesive member, and the density D of the sound absorption member c is 50 kg / m 3 or more, and when the thickness of the inner liner is T i (mm) and the maximum thickness of the sound absorption layer is T c (mm), it relates to a pneumatic tire in which D c ×(T c / T i ) is less than 7500.

Advantages of the Invention

[0008] According to the present invention, there is provided a tire capable of improving the overall performance of the durability performance of a sound absorption layer and the absorption suppression performance of a puncture repair liquid.

Brief Description of the Drawings

[0009] [Figure 1] It is a cross-sectional view of a pneumatic tire according to an embodiment of the present invention. [Figure 2] It is an enlarged cross-sectional view near the inner cavity surface of the tire.

Mode for Carrying Out the Invention

[0010] A pneumatic tire according to an embodiment of the present invention is a pneumatic tire including an inner liner and a sound absorption layer disposed on the inner cavity surface of the tire formed by the inner liner. The sound absorption layer includes a sound absorption member and an adhesive member, and the density D of the sound absorption member c is 50 kg / m 3 or more, and the thickness of the inner liner is T i(mm), the maximum thickness of the sound-absorbing layer is T c If (mm), then D c ×(T c / T i These are pneumatic tires with a voltage of less than 7500.

[0011] While not intended to be constrained by theory, the mechanism by which the overall performance of the sound-absorbing layer's durability and the puncture repair fluid absorption suppression performance is improved in the tire of the present invention can be considered as follows, for example.

[0012] (1) Density D of sound-absorbing material c 50 kg / m 3 By doing so, it is believed that the absorption of tire repair fluid into the sound-absorbing material can be suppressed.

[0013] (2) On the other hand, T c / T i If the size increases, the inner liner may not be able to adequately absorb the deformation during driving, and there is a concern that the durability of the sound-absorbing layer placed on the inner surface of the tire formed by the inner liner will decrease. Therefore, D c ×(T c / T i ) is set to less than 7500, T c / T i If the value is large, then D c By reducing the size of the sound-absorbing material, it is thought that the sound-absorbing material itself can absorb deformation during driving, thereby suppressing its destruction.

[0014] The combined effect of (1) and (2) above allows the sound-absorbing layer, which uses relatively high-density sound-absorbing material, to have a certain degree of flexibility. This is thought to achieve a remarkable effect in which the overall performance of the sound-absorbing layer, including its durability and its ability to suppress the absorption of tire repair fluid, is improved.

[0015] The aforementioned D c ×(T c / T i From the viewpoint of suppressing the absorption of puncture repair fluid, it is preferable that the value be 1500 or higher.

[0016] Density D of the sound-absorbing member c From the perspective of the durability performance of the sound-absorbing layer, 240 kg / m 3 The following is preferable:

[0017] The sound-absorbing member is fixed to the inner surface of the tire along the tire circumferential direction via the adhesive member, and the maximum thickness T of the adhesive member is a The maximum thickness T of the sound-absorbing layer is c Preferably, the amount is between 1.5% and 10.0%.

[0018] From the viewpoint of the effects of the present invention, the sound-absorbing member is preferably composed of one or more materials selected from the group consisting of sponge material and cork.

[0019] The adhesive member preferably contains an acrylic resin or a butyl rubber.

[0020] In this specification, numerical values ​​accompanied by "greater than or equal to," "greater than," "less than or equal to," or "less than" relating to the boundaries of a numerical range can be arbitrarily combined to constitute a numerical range, as long as it does not contradict the spirit of the present invention. Furthermore, these numerical values ​​can also be combined with the numerical values ​​in the examples as their upper or lower limits to constitute a numerical range. When a numerical range thus constructed is shown as including a boundary value, it can be interpreted, as long as it does not contradict the spirit of the present invention, to simultaneously show a numerical range that does not include that boundary value, in an arbitrarily selectable manner. Therefore, for example, a numerical range shown as including both boundary values ​​at both ends can be interpreted, as long as it does not contradict the spirit of the present invention, to show a numerical range that does not include either one of the boundary values, or a numerical range that does not include either boundary value. Also, a numerical range shown as including only one boundary value and not including the other boundary value can be interpreted, as long as it does not contradict the spirit of the present invention, to show a numerical range that does not include either boundary value.

[0021] [Definition] "Standard condition" refers to a state of no load where the tire is mounted on a standard rim and filled with air at the standard internal pressure. Unless otherwise specified, tires in the standard condition should be used.

[0022] Unless otherwise specified, the "dimensions of each part of the tire" refer to values ​​that are determined in the normal state for those visible on the outer surface of the tire, while those located inside the tire or on the cut surface of the tire refer to values ​​that are determined, for example, by cutting the tire in a plane including the tire's axis of rotation and holding the cut tire piece within the rim width of the normal rim.

[0023] A "standard rim" refers to the rim specified for each tire within the standards system that the tire is based on. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," for ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." Refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. In the case of a tire not specified in the above standards, it refers to the narrowest rim width among the smallest diameter rims that can be mounted on that tire and that can maintain internal pressure (i.e., do not cause air leakage between the rim and tire).

[0024] "Regular internal pressure" refers to the air pressure specified for each tire in the standards system, including the standard on which the tire is based. For example, for JATMA it refers to "maximum air pressure," for ETRTO it refers to "INFLATION PRESSURE," and for TRA it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims, refer to JATMA, ETRTO, and TRA in that order, and if there is an applicable size at the time of reference, follow that standard. In the case of tires not specified in the above standards, it refers to the regular internal pressure (but at least 250kPa) of another tire size (but specified in the standard) that is listed with the aforementioned regular rim as the standard rim. If multiple regular internal pressures of 250kPa or higher are listed, refer to the lowest value among them.

[0025] "Regular load (kg)" refers to the load specified for each tire in the standard system that the tire is based on. For example, for JATMA it is "Maximum Load Capacity," for ETRTO it is "LOAD CAPACITY," and for TRA it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." As with regular rims and regular in-tire pressure, refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. For tires not specified in the above standards, the maximum load capacity (kg) is calculated separately. L This is considered the normal load.

[0026] "Maximum load capacity W L The weight (kg) is calculated using the following formula: "V" is the virtual volume of the tire (mm²). 3), "Dt" is the outer diameter of the tire in the normal state (mm), "Ht" is the height of the tire's cross-section in the radial direction in a plane containing the tire's axis of rotation (mm), and "Wt" is the width of the tire's cross-section in the normal state (mm). Ht can be calculated by (Dt-R) / 2, where R is the rim diameter of the tire. Wt is the value obtained by removing any patterns or letters on the tire's sidewall. Note that the maximum load capacity is synonymous with the normal load mentioned above.

[0027]

number

[0028] "Tread contact point Te" refers to the outermost contact point in the tire's axial direction when a tire in a normal state is subjected to a normal load, has a camber angle of 0 degrees, and is in contact with a flat surface.

[0029] "Tread contact width" refers to the distance between the tread contact edges Te in the tire's axial direction.

[0030] "Maximum thickness of sound-absorbing layer T" c " is the maximum thickness of the sound-absorbing layer measured along the normal to the inner surface of the tire in a cross-section obtained by cutting the tire in a plane containing the tire's axis of rotation.

[0031] "Inner liner thickness T i This is the thickness measured along the aforementioned normal where the sound-absorbing layer has its maximum thickness.

[0032] "Maximum thickness T of adhesive material" a This refers to the maximum thickness of the adhesive member measured along the normal to the inner surface of the tire, in a cross-section obtained by cutting the tire in a plane containing the tire's rotation axis. Note that the normal at which the adhesive member has its maximum thickness may differ from the normal at which the sound-absorbing layer has its maximum thickness, as shown in Figure 2.

[0033] The procedure for manufacturing a pneumatic tire, which is one embodiment of the present invention, will be described in detail below. However, the following description is illustrative for explaining the present invention and is not intended to limit the technical scope of the present invention to this scope only.

[0034] <Air-filled tires> The pneumatic tire according to this embodiment comprises an inner liner and a sound-absorbing layer disposed on the inner surface of the tire cavity formed by the inner liner. A tire according to one embodiment of the present invention will be described below with reference to the drawings, but the drawings are for illustrative purposes only. Furthermore, the embodiments described below are merely examples.

[0035] Figure 1 is a cross-sectional view of a tire as shown by a plane passing through the tire's axis of rotation, showing only the right side as it is divided by the tire's centerline CL. The tire in Figure 1 comprises a tread 1, a pair of sidewalls 31 arranged on both sides of the tread, an inner liner 32, a sound-absorbing layer 6 arranged on the inner surface 7 of the tire formed by the inner liner 32, a pair of bead portions having a bead core 21, at least one carcass 33 anchored to the bead core 21, at least one belt 2 arranged on the radially outer side of the carcass 33, and a band 3 reinforcing the belt 2.

[0036] The sound-absorbing layer 6 is preferably a long, strip-shaped piece having a bottom surface that is fixed to the inner surface of the tire 7. The sound-absorbing layer 6 can be formed in a substantially annular shape by butting its outer ends together in the circumferential direction, or the outer ends may be spaced apart in the circumferential direction.

[0037] The sound-absorbing layer 6 has substantially the same cross-sectional shape at all circumferential positions except for the outer end. To prevent tilting or deformation during driving, a flat, elongated cross-sectional shape with a height smaller than the width in the tire axial direction is preferred. The specific cross-sectional shape is not particularly limited; various shapes such as rectangular, trapezoidal, triangular, and semicircular can be used. Furthermore, multiple sound-absorbing layers 6 may be arranged spaced apart in the tire axial direction.

[0038] In Figure 1, the sound-absorbing layer 6 is provided with grooves 9 that extend continuously in the circumferential direction on the inner surface in the radial direction of the tire, but the configuration is not limited to this. Providing grooves 9 is thought to increase the surface area of ​​the sound-absorbing layer 6, allowing it to absorb more resonance energy, and also to improve heat dissipation, making it easier to suppress the temperature rise of the sound-absorbing layer. Electronic components such as wireless tags equipped with sensors for detecting the internal state of the tire, such as tire pressure, and recording units for unique tire identification information, may be fixed to the grooves 9.

[0039] The sound-absorbing layer 6 is preferably located within 120% of the tread contact width, centered on the tire centerline CL, and more preferably within 110%. The width of the sound-absorbing layer 6 in the tire axial direction (or the sum of the widths of multiple sound-absorbing layers 6 spaced apart in the tire axial direction) is preferably 30% or more of the tread contact width, preferably 40% or more, and more preferably 50% or more. The width of the sound-absorbing layer 6 in the tire axial direction may also be 100% of the tread contact width, and is preferably 90% or less.

[0040] The sound-absorbing layer 6 according to this embodiment includes a sound-absorbing member 5 and an adhesive member 4. Figure 2 is an enlarged cross-sectional view near the inner surface of the tire. In Figure 2, the sound-absorbing member 5 is fixed to the inner surface of the tire 7 along the circumferential direction of the tire via the adhesive member 4, but the embodiment is not limited to this, and the sound-absorbing layer may be formed, for example, by embedding the sound-absorbing member in the adhesive member.

[0041] The thickness of the adhesive member 4 may be uniform or non-uniform in the tire axial direction. Furthermore, multiple adhesive members 4 may be arranged within a single sound-absorbing layer 6, spaced apart in the tire axial direction. Figure 2 illustrates a case where the thickness of the adhesive member 4 is non-uniform in the tire axial direction.

[0042] Maximum thickness T of adhesive member 4 a From the viewpoint of ensuring adhesion of the sound-absorbing member 5, the thickness is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. Also, the maximum thickness T of the adhesive member 4. aThe thickness is preferably 5.0 mm or less, more preferably 3.0 mm or less, and even more preferably 1.8 mm or less.

[0043] Maximum thickness T of adhesive member 4 a The maximum thickness T of the sound-absorbing layer c Preferably, it is 1.5% or more, more preferably 2.0% or more, even more preferably 2.5% or more, and particularly preferably 3.0% or more. Also, the maximum thickness T of the adhesive member 4. a The maximum thickness T of the sound-absorbing layer c Preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 6.0% or less.

[0044] The adhesive member 4 may be formed solely from an adhesive, or it may be a double-sided tape or the like having an adhesive and a base material.

[0045] The adhesives that can be used for the adhesive member 4 are not particularly limited, but examples include inorganic adhesives such as sodium silicate, cement, and ceramics; natural adhesives such as starch, protein, natural rubber, and asphalt; thermoplastic resin adhesives such as vinyl acetate resin, polyvinyl acetal resin, ethylene vinyl acetate resin, vinyl chloride resin, acrylic resin, polyamide resin, cellulose resin, and α-olefin resin; thermosetting resin adhesives such as urea resin, melamine resin, phenolic resin, resorcinol resin, epoxy resin, and polyester resin; and elastomer adhesives such as styrene-butadiene rubber, butyl rubber, chloroprene rubber, nitrile rubber, silicone rubber, and acrylic rubber, with acrylic resin or butyl rubber being preferred.

[0046] The substrate that can be used for the adhesive member 4 is not particularly limited, but examples include plastic films such as polyethylene, polypropylene, polyvinyl chloride, and polyester; rayon, pulp, synthetic fibers, woven fabrics, nonwoven fabrics, and cotton fabrics.

[0047] The material of the sound-absorbing member 5 is not particularly limited, but examples include sponge material, glass wool, rock wool, cork, polystyrene foam, felt, nonwoven fabric, loop pile fabric, etc. In this embodiment, the sound-absorbing member is preferably composed of one or more selected from the group consisting of sponge material, rock wool, and cork.

[0048] The sponge material is a porous structure, and its cells (pores) may be interconnected or closed, but interconnected pores are preferable.

[0049] As the porous structure, foamed synthetic resin or synthetic rubber is preferably used, but a web-like structure in which animal fibers, plant fibers, or synthetic fibers are intertwined and linked together may also be used.

[0050] The material of the foam is not particularly limited, but examples include synthetic resins such as polyurethane, polystyrene, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer (EVA); and synthetic rubbers such as ethylene-propylene-diene rubber (EPDM), silicone rubber, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butyl rubber, chloroprene rubber, acrylic rubber, and epichlorohydrin rubber (ECO). Among these, polyurethane is preferred from the viewpoint of sound dampening, lightness, controllability of foaming, and durability.

[0051] For example, when polyurethane foam is used as a sponge material, the polyurethane foam can be manufactured using polyurethane raw materials such as polyols, polyisocyanates, catalysts, foam stabilizers, and blowing agents by known methods.

[0052] If the sponge material is a foam, its density can be adjusted as appropriate by changing the type and amount of catalysts, foam stabilizers, blowing agents, etc., that are blended into the raw materials.

[0053] From the viewpoint of sufficient conversion of air vibration energy, the volume of the sound-absorbing layer is preferably 1% or more, preferably 3% or more, and more preferably 5% or more of the total volume of the tire cavity. Furthermore, the volume of the sound-absorbing layer is preferably 30% or less, preferably 25% or less, and more preferably 20% or less of the total volume of the tire cavity.

[0054] Here, the volume of the sound-absorbing layer refers to the apparent total volume of the sound-absorbing layer, which is determined from the external shape including the internal air bubbles. In this specification, the total volume Vi of the tire cavity is to be approximately determined by the following formula (1) in an unloaded, normal state with the tire mounted on a normal rim and filled with normal internal pressure. Below, A refers to the area enclosed by the line segment connecting the inner radial endpoints of the tire and the surface of the tire cavity and the pair of bead portions. Vi=A×{(Di-Dr) / 2+Dr}×π ···(1) A: Cross-sectional area (mm) of the tire cavity obtained by CT scanning a tire-rim assembly in a normal state. Di: Maximum outer diameter of the inner surface of the tire in its normal state (mm) Dr: Rim diameter (mm)

[0055] Density D of sound-absorbing material c From the perspective of suppressing the absorption of tire repair fluid, the limit is 50 kg / m³. 3 That is all. 55 kg / m 3 The above is preferable, and 60 kg / m 3 The above is more preferable: 70 kg / m 3 The above is even more preferable, 80 kg / m 3 The above is even more preferable, 90 kg / m 3 The above is particularly preferable. On the other hand, the density D of the sound-absorbing member c From the perspective of the durability of the sound-absorbing layer, 300 kg / m 3 The following is preferable: 280 kg / m 3 The following is more preferable: 260 kg / m 3 The following is even more preferable: 240 kg / m 3 The following are particularly preferable.

[0056] Maximum thickness T of the sound-absorbing layer cFrom the viewpoint of noise suppression performance, a thickness of 10 mm or more is preferable, 15 mm or more is more preferable, 20 mm or more is even preferable, and 25 mm or more is particularly preferable. On the other hand, the maximum thickness T of the sound-absorbing layer c From the viewpoint of the effects of the present invention, a length of 50 mm or less is preferred, 45 mm or less is more preferred, 40 mm or less is even more preferred, and 35 mm or less is particularly preferred.

[0057] Inner liner thickness T i The thickness of the inner liner T is preferably 0.5 mm or more, more preferably 0.6 mm or more, even more preferably 0.7 mm or more, even more preferably 0.8 mm or more, and particularly preferably 0.9 mm or more. i The thickness is preferably 2.0 mm or less, more preferably 1.8 mm or less, even more preferably 1.6 mm or less, even more preferably 1.4 mm or less, and particularly preferably 1.2 mm or less.

[0058] T c / T i From the viewpoint of the durability performance of the sound-absorbing material, a value of 100 or less is preferred, 80 or less is more preferred, 60 or less is even more preferred, 50 or less is even more preferred, 45 or less is even more preferred, and 40 or less is particularly preferred. On the other hand, T c / T i The lower limit is not particularly restricted, but it is preferably 10 or more, more preferably 15 or more, even more preferably 20 or more, and particularly preferably 25 or more.

[0059] D c ×(T c / T i ) is less than 7500 from the viewpoint of the durability performance of the sound-absorbing material, preferably 7200 or less, more preferably less than 6000, even more preferably less than 5000, even more preferably less than 4000, even more preferably 3000 or less, and particularly preferably less than 2000. On the other hand, D c ×(T c / T i From the viewpoint of suppressing the absorption of tire repair fluid, a value of 900 or higher is preferable, 1100 or higher is more preferable, 1300 or higher is even preferable, and 1500 or higher is particularly preferable.

[0060] The pneumatic tire according to this embodiment can be manufactured by conventional methods using the inner liner and sound-absorbing layer described above. That is, an unvulcanized tire can be formed by bonding the inliner together with other tire components on a tire molding machine and molding it in a conventional method, and a pneumatic tire can be manufactured by heating and pressurizing this unvulcanized tire in a vulcanizing machine. The sound-absorbing layer is formed, for example, by fixing a sound-absorbing member to the inner surface of the tire cavity along the circumferential direction of the tire via the adhesive member described above.

[0061] <Application> The tire according to this embodiment can be a general-purpose tire such as a passenger car tire, a truck / bus tire, or a motorcycle tire, but it can also be a tire for an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. A passenger car tire refers to a tire intended for use on a four-wheeled vehicle, with a maximum load capacity of 1000 kg or less. Furthermore, the tire according to this embodiment can be used as an all-season tire, a summer tire, or a winter tire such as a studless tire. [Examples]

[0062] The following describes examples (examples) that are considered preferable for implementation, but the scope of the present invention is not limited to these examples. Each pneumatic tire for testing, having the basic structure shown in Figure 1 and the specifications in the table below, was examined, and the results calculated based on the evaluation method described below are shown in Tables 1 and 2.

[0063] (Examples and Comparative Examples) An unvulcanized tire is produced by bonding the inner liner together with other tire components on a tire molding machine, and then vulcanized at 170°C to obtain the pneumatic tires (size: 245 / 45R18) for each test as described in Tables 1 and 2. Then, a sound-absorbing layer is formed by fixing the sound-absorbing material to the inner surface of the tire cavity along the tire circumferential direction via an adhesive material. The adhesive material is made only from acrylic resin, the width of the sound-absorbing layer in the tire axial direction is 80% of the tread contact width, and the volume of the sound-absorbing layer is 20% of the total volume of the inner cavity of the tire.

[0064] <Durability of the sound-absorbing layer> Each test tire is mounted on a standard rim, the internal pressure is adjusted to 230 kPa, and the durability of the sound-absorbing layer is evaluated using a drum testing machine. The load is set to a load equal to or greater than the standard load. The vehicle is driven at a speed of 80 km / h, and the distance until the sound-absorbing layer and its vicinity are damaged is measured. The results are expressed as an index with the value of the reference comparative example (Comparative Example 2 in Table 1, Comparative Example 5 in Table 2) set to 100. A higher index indicates better durability of the sound-absorbing layer.

[0065] <Absorption inhibition performance of tire repair fluid> Each test tire is mounted on the rim described above and punctured by a nail. Then, each tire is repaired using tire repair fluid (main component: rubber latex), and the time required for repair is measured. The results are expressed as an exponential value, with the reciprocal of the measured time set to 100, representing the value of the reference comparative example (Comparative Example 2 in Table 1, Comparative Example 5 in Table 2). A larger exponential value indicates a shorter repair time and suppressed absorption of the tire repair fluid into the sound-absorbing layer.

[0066] <Overall Performance> The sum of the sound-absorbing layer's durability performance index and the tire repair fluid's absorption suppression performance index is displayed as the overall performance index.

[0067] [Table 1]

[0068] [Table 2]

[0069] <Embodiment> Examples of embodiments of the present invention are shown below. [1] A pneumatic tire comprising an inner liner and a sound-absorbing layer disposed on the inner surface of the tire formed by the inner liner, wherein the sound-absorbing layer includes a sound-absorbing member and an adhesive member, and the density D of the sound-absorbing member c 50 kg / m 3 The above is true, and the thickness of the inner liner is T i (mm), the maximum thickness of the sound-absorbing layer is T c If (mm), then D c ×(T c / T i Pneumatic tires with a voltage of less than 7500. [2] D c ×(T c / T i A pneumatic tire as described in [1] above, wherein the ratio is less than 4000. [3] D c ×(T c / T i A pneumatic tire as described in [1] above, wherein the ratio is less than 2000. [4] The above D c ×(T c / T i A pneumatic tire as described in any of the above [1] to [3], having a value of 1500 or more. [5] Density D of the sound-absorbing member c 240 kg / m 3 A pneumatic tire as described in any of the above [1] to [4]. [6] The sound-absorbing member is fixed to the inner surface of the tire along the tire circumferential direction via the adhesive member, with the maximum thickness T of the adhesive member. a The maximum thickness T of the sound-absorbing layer is c A pneumatic tire as described in any of the above [1] to [5], having a percentage of 1.5% or more and 10.0% or less. [7] The pneumatic tire according to any one of [1] to [6] above, wherein the sound-absorbing member is composed of one or more selected from the group consisting of sponge material and cork. [8] The pneumatic tire according to any one of [1] to [6] above, wherein the bonding member contains an acrylic resin or a butyl rubber.

Explanation of Signs

[0070] 1 Tread 2 Belt 3 Band 4 Bonding member 5 Sound-absorbing member 6 Sound-absorbing layer 7 Inner surface of tire cavity 9 Groove 21 Bead core 31 Sidewall 32 Inner liner 33 Carcass CL Tire center line Te Tread grounding end T a Maximum thickness of bonding member T c Maximum thickness of sound-absorbing layer T i Thickness of inner liner

Claims

1. A pneumatic tire comprising an inner liner and a sound-absorbing layer disposed on the inner surface of the tire cavity formed by the inner liner, The sound-absorbing layer includes a sound-absorbing member and an adhesive member. Density D of the sound-absorbing member c 50 kg / m 3 That's all. The thickness of the inner liner is T i (mm), the maximum thickness of the sound-absorbing layer is T c If we use (mm), then D c × (T c / T i A pneumatic tire with a voltage of less than 7500.

2. Said D c × (T c / T i ) is less than 4000, the pneumatic tire according to claim 1.

3. The aforementioned D c × (T c / T i The pneumatic tire according to claim 1, wherein the coefficient of force is less than 2000.

4. The aforementioned D c × (T c / T i The pneumatic tire according to claim 1, wherein the coefficient of force is 1500 or more.

5. Density D of the sound-absorbing member c 240 kg / m 3 The following is the pneumatic tire according to claim 1.

6. The sound-absorbing member is fixed to the inner surface of the tire cavity along the tire circumferential direction via the adhesive member. The maximum thickness T of the adhesive member a The maximum thickness T of the sound-absorbing layer is c A pneumatic tire according to claim 1, wherein the amount is 1.5% or more and 10.0% or less.

7. The pneumatic tire according to any one of claims 1 to 6, wherein the sound-absorbing member is composed of one or more selected from the group consisting of sponge material and cork.

8. The pneumatic tire according to any one of claims 1 to 6, wherein the adhesive member comprises an acrylic resin or a butyl rubber.

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