Pneumatic tire

Abstract

To provide a pneumatic tire in which an electronic component is arranged, which is configured so that a carcass cord is suppressed from being damaged at a portion where the electronic component is arranged, while being reduced in weight.SOLUTION: A pneumatic tire according to the present invention includes a tread part 2, a pair of side wall parts 3, a pair of bead parts 4, a toroidal-shape carcass 6, an inner liner layer 10 and an electronic component 21. The carcass 6 includes a plurality of carcass cords 15 and a carcass ply 6A. The inner liner layer 10 includes a butyl-system rubber layer 11 and an insulation rubber layer 12. The butyl-system rubber layer 11 is arranged to form an inner cavity surface of the tire. The insulation rubber layer 12 is locally arranged with a length in a radial direction smaller than a length of the butyl-system rubber layer 11. The electronic component 21 is arranged between the butyl-system rubber layer 11 and the insulation rubber layer 12 so as not to contact a topping rubber layer 16.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in order to reduce the weight of tires, tires have been proposed in which an inner liner is joined to a carcass without using a tie gum layer (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-147024 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned tire, if an electronic component such as an RFID tag is embedded between the inner liner and the carcass, the electronic component may come into contact with the carcass cord, which may cause fatigue failure of the carcass cord during driving.

[0005] The present invention has been devised in consideration of the above-described circumstances, and has as its main objective to reduce the weight of a tire in which electronic components are arranged, while suppressing damage to the carcass cords in the areas where the electronic components are arranged. [Means for solving the problem]

[0006] The present invention provides a pneumatic tire including a tread portion, a pair of sidewall portions, a pair of bead portions each having a bead core embedded therein, a toroidal carcass extending between the bead cores of the pair of bead portions, a toroidal inner liner layer extending between the pair of bead portions on the inside of the carcass, and at least one electronic component disposed between the carcass and the inner liner layer, the carcass including a carcass ply including a plurality of carcass cords and a topping rubber layer covering the plurality of carcass cords, and the inner liner layer includes a braided rubber layer. a butyl-based rubber layer and an insulation rubber layer made of a rubber having a higher adhesive strength to the topping rubber layer than the butyl-based rubber layer, the butyl-based rubber layer being arranged so as to form a tire inner cavity surface, the insulation rubber layer being arranged between the butyl-based rubber layer and the topping rubber layer and being locally arranged with a radial length smaller than that of the butyl-based rubber layer, and the electronic component being arranged between the butyl-based rubber layer and the insulation rubber layer so as not to come into contact with the topping rubber layer. Effect of the Invention

[0007] By adopting the above-described configuration, the pneumatic tire of the present invention can be made lighter and damage to the carcass cords in the areas where electronic components are arranged can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a pneumatic tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of the carcass ply and the inner liner layer of FIG. [Diagram 3] FIG. 2 is an enlarged view of a bead portion in FIG. [Figure 4] FIG. 4 is an enlarged perspective view of the electronic module of FIG. 3. [Diagram 5] FIG. 4 is an enlarged cross-sectional view of the carcass, inner liner layer, and electronic module of FIG. 3. [Figure 6]FIG. 2 is a cross-sectional view of a pneumatic tire according to another embodiment of the present invention. [Figure 7] FIG. 2 is a cross-sectional view of a pneumatic tire according to another embodiment of the present invention. [Figure 8] FIG. 2 is a cross-sectional view of a pneumatic tire according to another embodiment of the present invention. [Figure 9] FIG. 2 is a cross-sectional view of a pneumatic tire of Comparative Example 1. [Figure 10] FIG. 4 is a cross-sectional view of a pneumatic tire of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, some embodiments of the present invention will be described with reference to the drawings. Although the drawings are described to include the features of the present invention, in order to facilitate understanding of the present invention, exaggerated expressions and expressions different from the dimensional ratios of the actual structure may be included. Furthermore, the same or common elements are given the same reference numerals throughout the embodiments, and duplicated explanations are omitted. FIG. 1 is a cross-sectional view showing a cross section of a pneumatic tire 1 (hereinafter, sometimes simply referred to as a "tire") of this embodiment in a normal state. Note that FIG. 1 is a diagram showing a cross section of the tire 1 when the tire 1 extending in an annular shape is cut by a virtual plane that passes through the tire rotation axis and is perpendicular to the tire circumferential direction. The tire 1 of this embodiment is suitably used for passenger cars, for example.

[0010] In the case of a pneumatic tire for which various standards are established, the normal state refers to a state in which the tire is mounted on a normal rim, inflated to a normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established, the normal state refers to a standard usage state according to the intended use of the tire, and a state in which no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal state. In addition, the dimensions of components that cannot be measured in the normal state (for example, the internal materials of tire 1) are values ​​measured with tire 1 in a state as close as possible to the normal state.

[0011] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0012] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0013] 1, a tire 1 of this embodiment includes a tread portion 2, a pair of sidewall portions 3, and a pair of bead portions 4. A bead core 5 is embedded in each of the bead portions 4. The tire 1 also includes a carcass 6, an inner liner layer 10, and at least one electronic component 21.

[0014] The carcass 6 extends in a toroidal shape between the bead cores 5 of the pair of bead portions 4. The carcass 6 of this embodiment is, for example, composed of one carcass ply 6A. The carcass ply 6A includes, for example, a main body portion 6a and a turn-up portion 6b. The main body portion 6a extends, for example, between the two bead portions 4. As a result, the main body portion 6a extends from at least the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. The turn-up portion 6b is, for example, connected to the main body portion 6a and turned up around the bead core 5 from the inner side in the tire axial direction to the outer side. Between the main body portion 6a and the turn-up portion 6b, a bead apex 8 extending from the bead core 5 to the outer side in the tire radial direction is disposed, and the bead portion 4 is appropriately reinforced.

[0015] The inner liner layer 10 extends in a toroidal shape between the pair of bead portions 4 inside the carcass 6 .

[0016] Fig. 2 shows an enlarged cross-sectional view of the carcass ply 6A and the inner liner layer 10. Fig. 2 is a cross-sectional view of the carcass ply 6A and the inner liner layer 10 at a position avoiding the electronic component 21. In Fig. 2, the rubber member on the tire outer surface side of the carcass ply 6A is omitted. As shown in Fig. 2, the carcass ply 6A includes a plurality of carcass cords 15 and a topping rubber layer 16 that covers the plurality of carcass cords 15.

[0017] For example, organic fiber cords such as aramid, rayon, etc. are used as the carcass cords 15. The carcass cords 15 are desirably arranged at an angle of 70 to 90° with respect to the tire equator C, for example.

[0018] Examples of the rubber component of the topping rubber layer 16 of the carcass 6 include diene rubbers such as isoprene rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). These may be used alone or in combination of two or more. Among these, isoprene rubber, SBR, and BR are preferred.

[0019] The above-mentioned configuration of the carcass ply 6A is an example, and a known configuration can be applied to the carcass 6 in the present invention. In addition, as shown in FIG. 1, in the tread portion 2 of the tire 1 of this embodiment, a belt layer 7 including a metallic belt cord is provided on the tire radially outer side of the carcass 6. The belt layer 7 includes, for example, two belt plies 7A and 7B. Each of the two belt plies 7A and 7B has a plurality of belt cords arranged at an angle of 15 to 45° with respect to the tire circumferential direction. The belt cords of one belt ply 7A and the belt cords of the other belt ply 7B are inclined in opposite directions with respect to the tire circumferential direction. This effectively reinforces the tread portion 2.

[0020] The electronic component 21 is disposed between the carcass 6 and the inner liner layer 10. In this embodiment, one electronic component 21 is disposed in one of the pair of bead portions 4 (the left side in FIG. 1 ). However, the present invention is not limited to this embodiment, and the electronic component 21 may be provided in, for example, the sidewall portion 3 or the tread portion 2.

[0021] Fig. 3 shows an enlarged cross-sectional view of the bead portion 4 in which the electronic component 21 is disposed. Fig. 4 shows an enlarged perspective view of an electronic module 20 including the electronic component 21. The outer surface of the electronic module 20 in Fig. 4 is dotted. As shown in Figs. 3 and 4, the electronic component 21 is covered with a cover rubber 22, and hereinafter in this specification, a member consisting of the electronic component 21 and the cover rubber 22 is referred to as the electronic module 20. In another embodiment, the electronic component 21 may be directly disposed between the carcass 6 and the inner liner layer 10.

[0022] Examples of the electronic component 21 include an RFID tag, a pressure sensor, a temperature sensor, an acceleration sensor, and a magnetic sensor. The electronic component 21 of this embodiment is an RFID tag. As shown in FIG. 4, the RFID tag is a small and lightweight electronic component composed of a metallic main body 21a equipped with an IC chip including a transmission / reception circuit, a control circuit, a memory, and the like, and an antenna 21b. When the RFID tag receives a query radio wave, it uses the received radio wave as electric energy and transmits various data in the memory as a response radio wave. This RFID tag employs a known configuration, and detailed description thereof will be omitted in this specification.

[0023] A known rubber having excellent adhesiveness is appropriately used for the cover rubber 22. For the cover rubber 22, the same rubber as that for the topping rubber layer 16 (shown in FIG. 2) of the carcass ply 6A described above may be used.

[0024] As shown in FIG. 1, the inner liner layer 10 includes a butyl-based rubber layer 11 and an insulation rubber layer 12. In each drawing in this specification, dots are applied to the insulation rubber layer 12. The butyl-based rubber layer 11 is disposed so as to form the tire inner cavity surface 1i side. The butyl-based rubber layer 11 has extremely low air permeability and can maintain the tire internal pressure. The butyl-based rubber layer 11 contains, for example, 80% or more of butyl rubber or halogenated butyl rubber.

[0025] The insulation rubber layer 12 is made of a rubber having a higher adhesive strength to the topping rubber layer 16 (shown in FIG. 2) of the carcass ply 6A than the butyl-based rubber layer 11. The insulation rubber layer 12 is preferably made of an elastomer composition containing, for example, natural rubber or styrene-butadiene rubber. The insulation rubber layer 12 is disposed between the butyl-based rubber layer 11 and the topping rubber layer 16 of the carcass ply 6A. The insulation rubber layer 12 is locally disposed with a radial length smaller than that of the butyl-based rubber layer 11. Here, "locally" means that the insulation rubber layer 12 is not disposed over the entire area of ​​the tire cavity surface. For this reason, in the present invention, the insulation rubber layer 12 may be disposed partially in the bead portion 4 as in the embodiment shown in FIG. 1, or may be disposed over the bead portion 4 and the sidewall portion 3 as described later.

[0026] 5 shows an enlarged cross-sectional view of the carcass ply 6A, the inner liner layer 10, and the electronic components 21. In FIG. 5, each layer has a constant thickness and the carcass cords 15 are arranged at equal intervals to make the invention easier to understand, but the actual tire 1 may include deformations and distortions that are unavoidable in rubber products. As shown in FIG. 5, the electronic components 21 are arranged between the butyl-based rubber layer 11 and the insulation rubber layer 12 so as not to come into contact with the topping rubber layer 16. This allows the tire 1 of the present invention to be lightweight while suppressing damage to the carcass cords 15 at the locations where the electronic components are arranged. The reason for this is as follows.

[0027] In the present invention, the insulation rubber layer 12 for increasing the adhesive strength between the butyl-based rubber layer 11 and the carcass ply 6A is arranged locally, so that the volume of the inner liner layer 10 can be reduced and the weight can be reduced compared to conventional tires (tires in which a tie gum layer for adhering the butyl-based rubber layer extends in a toroidal shape over the entire tire).

[0028] Furthermore, the electronic component 21 of the present invention is disposed between the butyl-based rubber layer 11 and the insulation rubber layer 12 so as not to come into contact with the topping rubber layer 16. Therefore, even if the area in which the electronic component 21 is disposed (the bead portion 4 in this embodiment) is repeatedly deformed as the tire 1 is used, the electronic component 21 is less likely to come into contact with the carcass cord 15, and damage to the carcass cord 15 in the area in which the electronic component 21 is disposed can be suppressed.

[0029] A more detailed configuration of this embodiment will be described below. The configuration described below shows a specific embodiment of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the tire of the present invention having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0030] As shown in Fig. 1, the electronic module 20 including the electronic component 21 is preferably positioned at a distance of 3 mm or more from the outer surface of the bead core 5 in the tire radial direction outward in the tire radial direction. Also, the electronic module 20 is preferably positioned at a distance of 3 mm or more from the outer end of the belt layer 7 in the tire axial direction inward in the tire radial direction. This allows the electronic module 20 to be positioned away from the metal members included in the bead core 5 and the belt layer 7, thereby suppressing malfunctions of the electronic module 20 such as radio interference. The distance is specified as the distance in a direction parallel to the tire radial direction from the outer surface of the bead core 5 or the outer end of the belt layer 7 to the center of gravity of the electronic component 21 (shown in Fig. 4) included in the electronic module 20.

[0031] 3, the electronic module 20 is desirably disposed in the bead portion 4, and in this embodiment, is disposed axially inside the bead apex 8. This allows deformation around the electronic module 20 to be suppressed by the bead apex 8, further improving the durability of the tire.

[0032] From the viewpoint of obtaining the above-mentioned effects while ensuring a sufficient distance between the electronic component 21 and the bead core 5, it is preferable that the distance L1 in the tire radial direction from the inner end of the electronic module 20 in the tire radial direction to the outer surface of the bead core 5 is 50% to 60% of the height h1 in the tire radial direction of the bead apex 8. Also, it is preferable that the distance L2 from the outer end of the electronic module 20 in the tire radial direction to the outer end of the bead apex 8 in the tire radial direction is 25% to 35% of the height h1 of the bead apex 8.

[0033] More specifically, when the height h1 of the bead apex 8 is 35 mm or more, it is desirable that the distance L1 is 5 mm or more and the distance L2 is 7 mm or more. On the other hand, when the height h1 of the bead apex 8 is less than 35 mm, it may be difficult to sufficiently secure both the distance L1 and the distance L2. For this reason, when the height h1 is less than 35 mm, the distance L1 may be preferentially secured to be 5 mm or more, and the distance L2 may be less than 7 mm.

[0034] As shown in Fig. 4, in electronic component 21 of this embodiment, antenna 21b extends in a spiral shape around main body 21a. Such electronic component 21 can exhibit excellent durability because main body 21a is protected by antenna 21b. Helical outer diameter A1 (shown in Fig. 5) of antenna 21b is, for example, 1.5 to 2.5 mm, and preferably 1.8 to 2.0 mm. Total length of electronic component 21 (total length including antenna 21b) is, for example, about 35 to 50 mm.

[0035] On the other hand, the cover rubber 22 has a total length greater than the total length of the electronic component 21 so as to completely cover the electronic component 21. Specifically, the cover rubber 22 is configured in a horizontally elongated and flattened rectangular parallelepiped shape having a first length La, a second length Lb, and a thickness ta. The first length La is a length in the tire circumferential direction, and is, for example, 45 to 70 mm. The second length Lb is a length in a direction perpendicular to the first length La, and corresponds to a length along the carcass ply 6A of the electronic module 20 in the tire cross section. The second length Lb is smaller than the first length La, and is, for example, 8 to 15 mm. The thickness ta is a thickness in a direction perpendicular to the first length La and the second length Lb. The thickness ta is smaller than the first length La and the second length Lb, and is, for example, 2.0 to 3.0 mm, and preferably 2.2 to 2.4 mm. In this specification, unless otherwise specified, the thickness of each part means the average thickness of each part. The "average thickness of each portion" is calculated by, for example, dividing the symmetrical portion into a number of equal microregions and dividing the sum of the thicknesses of the microregions by the number of the microregions.

[0036] The cover rubber 22 of this embodiment includes an inner layer 26 in contact with the butyl-based rubber layer 11 (shown in FIG. 5) and an outer layer 27 in contact with the insulation rubber layer 12 (shown in FIG. 5). In this embodiment, the electronic component 21 is disposed between the inner layer 26 and the outer layer 27 of the cover rubber 22. The thickness t1 of the outer layer 27 and the thickness t2 of the inner layer 26 are each preferably 0.8 to 1.5 mm, and more preferably 1.0 to 1.3 mm. This further improves durability.

[0037] As shown in Fig. 5, the cover rubber 22 has an interface 28 between the inner layer 26 and the outer layer 27. The electronic module 20 of this embodiment is arranged so as to ensure a first distance d1, which is the shortest distance from the interface 28 to an imaginary carcass cord reference plane 30. The imaginary carcass cord reference plane 30 means an imaginary plane connecting the surfaces of the multiple carcass cords 15, and specifically, is a plane or a smoothly curved surface passing through the ends of the carcass cords 15 on the tire cavity surface 1i side. In Fig. 5, the imaginary carcass cord reference plane 30 is indicated by a two-dot chain line.

[0038] Moreover, the electronic module 20 of this embodiment is disposed so as to ensure a second distance d2, which is the shortest distance from the interface 28 to the butyl-based rubber layer 11. The first distance d1 is, for example, 2.0 to 3.0 mm. The second distance d2 is, for example, 1.0 to 1.3 mm. If the second distance d2 is large, air may be trapped around the electronic module 20, resulting in a loss of durability. From this viewpoint, in a desirable embodiment, the ratio d1 / d2 of the first distance d1 to the second distance d2 is 1.8 to 2.2. This suppresses peeling at the interface 28.

[0039] The thickness t3 of the insulation rubber layer 12 is, for example, 0.2 to 1.5 mm, and preferably 0.4 to 1.1 mm. This can reliably prevent the electronic components 21 from coming into contact with the carcass cords 15.

[0040] If the shortest distance d3 from the carcass cord 15 to the electronic component 21 is small, the electronic component 21 and the carcass cord 15 are likely to come into contact with each other. On the other hand, if the shortest distance d3 is large, the tire weight increases and the tire uniformity may deteriorate. For this reason, the shortest distance d3 is preferably 0.5 mm or more, more preferably 0.7 mm or more, and is preferably 1.8 mm or less, more preferably 1.6 mm or less.

[0041] The shortest distance d4 from the butyl-based rubber layer 11 to the electronic component 21 is, for example, 0.1 to 0.4 mm. This makes it possible to prevent the electronic component 21 from coming into contact with the butyl-based rubber layer 11.

[0042] As shown in FIG. 1, in this embodiment, the insulation rubber layer 12 is disposed only in one of the pair of bead portions 4, and the insulation rubber layer 12 is not disposed in any other portion. However, as described later, the insulation rubber layer 12 may be disposed in other regions. From the viewpoint of reducing the weight of the tire, the total radial length of the insulation rubber layer 12 is preferably 50% or less of the total radial length of the tire cavity surface 1i, and more preferably 30% or less. In addition, from the viewpoint of suppressing peeling damage of the butyl-based rubber layer 11, the total radial length of the insulation rubber layer 12 is preferably 5% or more of the total radial length of the tire cavity surface 1i.

[0043] As shown in Fig. 3, the inner end 12i of the insulation rubber layer 12 in the tire radial direction is located at a position 5 mm or more away from the outer surface of the bead core 5 in the tire radial direction. In addition, in the tire cross section, the radial length L3 of the insulation rubber layer 12 is preferably 5 mm or more longer than the radial length of the cover rubber 22 (corresponding to the second length Lb shown in Fig. 4). Specifically, the length L3 of the insulation rubber layer 12 is preferably 4.0 to 6.0 times the length of the cover rubber 22. This reliably improves the durability of the tire.

[0044] The loss tangent tan δ of the insulation rubber layer 12 is desirably 0.16 or less in order to reliably suppress peeling damage and fatigue failure of the butyl-based rubber layer 11. The loss tangent tan δ is measured under the following conditions using a viscoelasticity spectrometer in accordance with the provisions of JIS-K6394. Initial distortion: 10% Amplitude: ±2% Frequency: 10Hz Deformation mode: tension Measurement temperature: 30℃

[0045] From the same viewpoint, the complex modulus E* of the insulation rubber layer 12 is desirably 4.0 MPa or more. The complex modulus E* is a value measured using a viscoelasticity spectrometer under the following conditions in accordance with the provisions of JIS-K6394. Initial distortion: 10% Amplitude: ±2% Frequency: 10Hz Deformation mode: tension Measurement temperature: 30℃

[0046] As shown in Fig. 5, the thickness t4 of the topping rubber layer 16 (the maximum thickness from the imaginary carcass cord reference plane 30 to the outer surface of the carcass ply 6A in the region in contact with the outer layer 27) is smaller than the thickness t1 (shown in Fig. 4) of the outer layer 27 and smaller than the thickness t3 of the insulation rubber layer 12, for example. Specifically, the thickness t4 of the topping rubber layer 16 is 0.10 to 0.30 mm. This allows the thickness of the carcass 6 to be reduced while ensuring durability, and allows the tire weight to be reduced.

[0047] Fig. 6 shows a cross-sectional view of a tire 1 according to another embodiment of the present invention. As shown in Fig. 6, in this embodiment, the insulation rubber layer 12 includes a first insulation rubber layer 12A in contact with the electronic module 20 and at least one second insulation rubber layer 12B not in contact with the electronic module 20. In this embodiment, the second insulation rubber layer 12B is provided on each of the pair of sidewall portions 3. This further suppresses peeling damage of the inner liner layer 10.

[0048] In a preferred embodiment, the outer end 12Bo in the tire radial direction of the second insulation rubber layer 12B is preferably located on the tire equator C side, at a distance of 10 mm or more from the outer end 7o in the tire axial direction of the belt layer 7. Also, the inner end 12Bi in the tire radial direction of the second insulation rubber layer 12B is preferably located on the bead core 5 side, at a distance of 5 mm or more from the tire maximum width position 3M of the sidewall portion 3. This ensures that the second insulation rubber layer 12B is disposed in an area of ​​the tire 1 that is easily deformed, thereby improving the durability of the tire.

[0049] Fig. 7 shows a cross-sectional view of a tire 1 according to still another embodiment of the present invention. As shown in Fig. 7, in this embodiment, an electronic module 20 is disposed in the bead portion 4, and an insulation rubber layer 12 in contact with the electronic module 20 extends to the sidewall portion 3. More specifically, an outer end 12o in the tire radial direction of the insulation rubber layer 12 is located closer to the tire equator C than an outer end 7o in the tire axial direction of the belt layer 7. Such an insulation rubber layer 12 can integrally reinforce the sidewall portion 3 and the bead portion 4, and can effectively suppress peeling damage of the butyl-based rubber layer 11.

[0050] In this embodiment, a second insulation rubber layer 12B similar to the embodiment shown in Fig. 6 is disposed on the sidewall portion 3 opposite to the side on which the electronic module 20 is disposed. This is expected to reduce the tire weight and improve durability. However, in yet another modification of the embodiment shown in Fig. 7, the second insulation rubber layer 12B may be disposed across the bead portion 4 and the sidewall portion 3, similar to the insulation rubber layer 12 on which the electronic module 20 is disposed.

[0051] Fig. 8 shows a cross-sectional view of a tire 1 according to still another embodiment of the present invention. As shown in Fig. 8, in this embodiment, an electronic component 21 and an insulation rubber layer 12 are provided in the sidewall portion 3. The sidewall portion 3 opposite to the insulation rubber layer 12 is provided with the second insulation rubber layer 12B of the embodiment shown in Fig. 6. In this embodiment, since the electronic component 21 is provided in the sidewall portion 3, the impact generated when the tire 1 is assembled to the rim is not easily transmitted to the electronic component 21, which helps to suppress damage to the electronic component 21 when assembled to the rim.

[0052] In this embodiment, the electronic component 21 is provided between the outer end 7o of the belt layer 7 and the tire maximum width position 3M. For example, the electronic component 21 may be provided at a position where the electronic module 20 overlaps with the tire maximum width position 3M (not shown).

[0053] Although several embodiments of the present invention have been described in detail above, the present invention is not limited to the above specific embodiments and can be modified and implemented in various aspects. EXAMPLES

[0054] A pneumatic tire for passenger cars having a size of 285 / 65R17 and having the basic structure of FIG. 1 was prototyped based on the specifications of Table 1. As Comparative Example 1, a tire having a cross section shown in FIG. 9 was prototyped. As Comparative Example 2, a tire having a cross section shown in FIG. 10 was prototyped. As shown in FIG. 9, in Comparative Example 1, a tie gum layer c is arranged so as to completely separate the carcass ply a and the butyl-based rubber layer b, and an electronic module d is arranged between the carcass ply a and the tie gum layer c. As shown in FIG. 10, in Comparative Example 2, a tie gum layer or an insulation rubber layer is not arranged between the carcass ply a and the butyl-based rubber layer b, and an electronic module d is arranged between the carcass ply a and the butyl-based rubber layer b. Comparative Examples 1 and 2 are substantially the same as the tires of the examples, except for the above-mentioned matters. The tire weight was measured for each test tire, and the durability of the tire was tested. The common specifications and test methods of the tires are as follows. Rim: 17×8.0 Tire pressure: 250kPa

[0055] <Tire weight> The weight of the tire not including the rim was measured. The results are shown as an index with the reciprocal of the tire weight of Comparative Example 1 set to 100, with a larger index value indicating a smaller tire weight.

[0056] <Tire durability> Each test tire was run at 120km / h on a drum testing machine with a constant vertical load (7.33kN) applied, and the running distance until damage occurred to the electronic module placement portion was measured. The results are shown as an index with the running distance of Comparative Example 1 set to 100, and the higher the value, the higher the durability of the tire. The test results are shown in Table 1.

[0057] [Table 1]

[0058] As shown in Table 1, the tire weight is large in Comparative Example 1, in which a tie gum layer is arranged to completely separate the carcass ply and the butyl-based rubber layer. Also, in Comparative Example 2, in which neither a tie gum layer nor an insulation rubber layer is arranged between the carcass ply and the butyl-based rubber layer, the tire durability is significantly reduced by 50 points.

[0059] In contrast, in Examples 1 to 6, the tire weight was smaller than Comparative Example 1, while the tire durability was maintained at 60 to 120 points, which was better than Comparative Example 2. In other words, it was confirmed that the present invention achieved weight reduction in a tire equipped with an electronic module while improving durability at the location of the electronic module.

[0060] [Note] The present invention includes the following aspects.

[0061] [Invention 1] A pneumatic tire, A tread portion; A pair of sidewall portions; A pair of bead portions each having a bead core embedded therein; a toroidal carcass extending between the bead cores of the pair of bead portions; a toroidal inner liner layer extending between the pair of bead portions on the inside of the carcass; at least one electronic component disposed between the carcass and the inner liner layer; The carcass includes a carcass ply including a plurality of carcass cords and a topping rubber layer covering the plurality of carcass cords, the inner liner layer includes a butyl-based rubber layer and an insulation rubber layer made of a rubber having a higher adhesive strength to the topping rubber layer than the butyl-based rubber layer; The butyl-based rubber layer is disposed so as to form a tire cavity surface, the insulation rubber layer is disposed between the butyl-based rubber layer and the topping rubber layer, and is locally disposed with a radial length smaller than that of the butyl-based rubber layer; the electronic component is disposed between the butyl-based rubber layer and the insulation rubber layer so as not to come into contact with the topping rubber layer; Pneumatic tires. [Invention 2] The electronic component is covered with a cover rubber, The pneumatic tire according to the first aspect of the present invention, wherein the shortest distance from the carcass cord to the electronic component is 0.5 to 1.8 mm. [Invention 3] 3. The pneumatic tire according to claim 2, wherein the shortest distance from the butyl rubber layer to the electronic component is 0.1 to 0.4 mm. [Invention 4] 4. The pneumatic tire according to any one of claims 1 to 3, wherein the insulation rubber layer has a loss tangent tan δ of 0.16 or less. [Invention 5] 5. The pneumatic tire according to any one of claims 1 to 4, wherein the insulation rubber layer has a complex modulus E* of 4.0 MPa or more. [Invention 6] The pneumatic tire according to any one of claims 1 to 5, wherein the electronic component includes a metallic main body having an IC chip, and an antenna extending spirally around the main body. [Invention 7] 7. The pneumatic tire according to claim 6, wherein the antenna has an outer spiral diameter of 1.8 to 2.0 mm. [Invention 8] an electronic module including a cover rubber that covers the electronic components; The bead portion includes a bead apex extending from the bead core outward in a radial direction of the tire, The pneumatic tire according to any one of claims 1 to 7, wherein the distance in the tire radial direction from the inner end of the electronic module in the tire radial direction to the outer surface of the bead core is 50% to 60% of the height of the bead apex in the tire radial direction. [The present invention 9] The pneumatic tire according to invention 9, wherein a distance L2 in the tire radial direction from an outer end of the electronic module in the tire radial direction to an outer end of the bead apex in the tire radial direction is 25% to 35% of the height of the bead apex. [The present invention 10] The carcass includes a plurality of carcass cords and a carcass cord reference surface passing through ends of the plurality of carcass cords on the tire inner cavity surface side, an electronic module including a cover rubber that covers the electronic components; the cover rubber includes an inner layer in contact with the butyl-based rubber layer, an outer layer in contact with the insulation rubber layer, and an interface between the inner layer and the outer layer; The pneumatic tire according to any one of claims 1 to 9, wherein a ratio d1 / d2 of a first distance d1 that is the shortest distance from the boundary surface to the carcass cord reference plane and a second distance d2 that is the shortest distance from the boundary surface to the butyl-based rubber layer is 1.8 to 2.2. [Explanation of symbols]

[0062] 2 Tread section 3 Sidewall 5 Bead Core 4 Bead section 6. Carcass 6A Carcass Ply 10 Inner liner layer 11 Butyl rubber layer 12 Insulation rubber layer 16 Topping rubber layer 15 Carcass Cord 21 Electronic Components

Claims

1. A pneumatic tire, A tread portion; A pair of sidewall portions; A pair of bead portions each having a bead core embedded therein; a toroidal carcass extending between the bead cores of the pair of bead portions; a toroidal inner liner layer extending between the pair of bead portions on the inside of the carcass; at least one electronic component disposed between the carcass and the inner liner layer; The carcass includes a carcass ply including a plurality of carcass cords and a topping rubber layer covering the plurality of carcass cords, the inner liner layer includes a butyl-based rubber layer and an insulation rubber layer made of a rubber having a higher adhesive strength to the topping rubber layer than the butyl-based rubber layer; The butyl-based rubber layer is disposed so as to form a tire cavity surface, the insulation rubber layer is disposed between the butyl-based rubber layer and the topping rubber layer, and is locally disposed with a radial length smaller than that of the butyl-based rubber layer; the electronic component is disposed between the butyl-based rubber layer and the insulation rubber layer so as not to come into contact with the topping rubber layer; Pneumatic tires.

2. The electronic component is covered with a cover rubber, 2. The pneumatic tire according to claim 1, wherein the shortest distance from the carcass cord to the electronic component is 0.5 to 1.8 mm.

3. 3. The pneumatic tire according to claim 2, wherein the shortest distance from the butyl rubber layer to the electronic component is 0.1 to 0.4 mm.

4. The pneumatic tire according to claim 1 or 2, wherein the insulation rubber layer has a loss tangent tan δ of 0.16 or less.

5. The pneumatic tire according to claim 1 or 2, wherein the insulation rubber layer has a complex modulus E* of 4.0 MPa or more.

6. The pneumatic tire according to claim 1 or 2, wherein the electronic component includes a metallic main body having an IC chip, and an antenna extending in a spiral shape around the main body.

7. 7. The pneumatic tire according to claim 6, wherein the antenna has an outer spiral diameter of 1.8 to 2.0 mm.

8. an electronic module including a cover rubber that covers the electronic components; The bead portion includes a bead apex extending from the bead core outward in a radial direction of the tire, 3. The pneumatic tire according to claim 1, wherein a distance in the tire radial direction from an inner end of the electronic module in the tire radial direction to an outer surface of the bead core is 50% to 60% of a height in the tire radial direction of the bead apex.

9. 9. The pneumatic tire according to claim 8, wherein a distance L2 in the tire radial direction from an outer end of the electronic module in the tire radial direction to an outer end of the bead apex in the tire radial direction is 25% to 35% of the height of the bead apex.

10. The carcass includes a plurality of carcass cords and a carcass cord reference surface passing through ends of the plurality of carcass cords on the tire inner cavity surface side, an electronic module including a cover rubber that covers the electronic components; the cover rubber includes an inner layer in contact with the butyl-based rubber layer, an outer layer in contact with the insulation rubber layer, and an interface between the inner layer and the outer layer; 3. The pneumatic tire according to claim 1, wherein a ratio d1 / d2 of a first distance d1 that is the shortest distance from the boundary surface to the carcass cord reference surface and a second distance d2 that is the shortest distance from the boundary surface to the butyl-based rubber layer is 1.8 to 2.2.

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