Pneumatic tires with sealant

Abstract

To provide a pneumatic tire having a sealant agent layer which has self-sealing characteristics and supports improved riding comfort and improved handling characteristics.SOLUTION: A pneumatic tire comprising a tread portion 10 having circumferential grooves 9 and circumferential ribs 8 or rows of tread blocks; an inner surface defining a tire cavity 6; and a sealant agent layer 5 at least partially covering the inner surface radially below the tread portion 10 within the tire cavity 6. The sealant agent layer 5 comprises raised portions 19 of a sealant agent, where the raised portion 19 of the sealant agent is provided radially below each of at least two of the circumferential grooves 9, and where the sealant agent layer 5 has larger radial thickness in the raised portions 19 than that in areas 18 radially below the circumferential ribs 8 or the rows of the tread blocks.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates in particular to pneumatic tires, and more specifically to pneumatic tires having on their inner surface a sealing layer that optionally supports at least one foamed member.

Background Art

[0002] Self-sealing pneumatic tires typically delay or prevent the loss of air pressure and the resulting shrinkage of the tire after it has been punctured by a sharp object such as a nail or screw. For puncture-sealing pneumatic tires, a plurality of methods, sealants, and tire structures have been proposed. However, most of these approaches have drawbacks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Sealants often help to efficiently seal puncture holes, but often result in added weight and insulation. As a result, ride comfort and handling performance may be limited and / or an undesirable heat distribution within the tire may occur. Such drawbacks can be even more severe when additional noise damping members are attached radially inside the sealant layer. In particular, such noise damping members can further adversely affect the temperature distribution within the tire.

[0005] Furthermore, attaching a noise-damping component to the sealant could potentially negatively affect the sealing performance of the sealant due to interaction with the noise-damping component.

[0006] Therefore, it is desirable to provide an improved tire that has good sealing performance and / or limited heat generation, along with low noise generation as a result of tire cavity resonance.

[0007] The first object of the present invention is to provide an advanced pneumatic tire having self-sealing properties.

[0008] Another object of the present invention is to provide an advanced pneumatic tire equipped with a sealant layer that supports improved ride comfort and handling characteristics.

[0009] Another object of the present invention is to provide an advanced pneumatic tire that is particularly fast, has improved high-speed characteristics and / or improved temperature behavior.

[0010] Another object of the present invention is to provide a sealant tire that is lightweight and preferably has limited tire cavity noise.

[0011] Another object of the present invention is to provide a cost-effective sealant tire, in particular a sealant tire with sufficient sound wave attenuation and sealing characteristics. [Means for solving the problem]

[0012] The present invention is defined by independent claim 1. Preferred embodiments are specified in the dependent claims and in the summary of the invention described below.

[0013] Accordingly, a first aspect of the present invention provides a pneumatic tire comprising a tread portion having i) circumferential grooves and ii) rows of circumferential ribs or tread blocks; two optionally provided bead portions; two sidewalls extending between the tread portions and each bead portion; an inner surface defining a tire cavity; and a sealant layer at least partially or completely covering the radially downward inner surface of the tread portion within the tire cavity. The sealant layer comprises sealant ridges, the sealant ridges being located radially downward of each of at least two circumferential grooves, and the sealant layer having a radial thickness greater in the ridges than in the radially downward region of the rows of circumferential ribs or tread blocks.

[0014] The arrangement of the sealant according to the present invention helps reduce heat generation below relatively thick tread ribs or tread blocks, but the thickness of the sealant is greater below at least two circumferential grooves (optionally below all circumferential grooves), particularly below the main circumferential grooves. In the groove regions, the tread has less rubber material than in the regions below the rows of ribs or tread blocks, and as a result, heat generation is limited in these regions below the grooves. Because the rubber thickness below the radial grooves is relatively thin, these sections are more easily punctured than areas with thicker rubber, such as below the tread ribs. A greater thickness of the sealant layer below the grooves helps reduce the higher risk of puncture in these groove regions. Providing a relatively thick sealant layer across the entire axial width of the tread would be undesirable, as it would result in higher heat generation below the entire tread section.

[0015] In one embodiment, each ridge (or ridge) has an axial width ranging from 70% to 130% of the axial width of the bottom of the circumferential groove located radially above the ridge. Thus, one ridge covers at least a substantial axial width of the groove radially above or outside the ridge. Having a smaller or larger width is undesirable, as it impairs either sealing or thermal conductivity.

[0016] In other embodiments, the raised portion of the sealant is provided radially below each of the circumferential grooves. Such arrangement provides the preferred effects of the present invention to all circumferential grooves.

[0017] In one embodiment, the pneumatic tire includes at least two (preferably at least three, more preferably at least four, or even more preferably at least five) circumferential grooves and at least three (preferably at least four, more preferably at least five, or even more preferably at least six) rows of circumferential ribs or tread blocks. The circumferential grooves may also be described as circumferential main grooves.

[0018] In other embodiments, the protrusions extend circumferentially over at least 95% of the inner circumference or inner surface of the tire (particularly at the axial position of each protrusion).

[0019] In other embodiments, the maximum radial thickness of the ridge, measured from the inner surface of the tire to the innermost radial surface of each ridge, is in the range of 3 mm to 9 mm (preferably 3 mm or 4 mm to 8 mm). Generally, the radial inner surface, or in other words, the inner surface, is preferably formed by the inner liner of the tire.

[0020] In yet another embodiment, the radial thickness of the sealant layer is in the range of 2 mm to 6 mm (preferably 3 mm to 5 mm) at an axial position midway between two adjacent ridges. Unless otherwise specified herein, the two adjacent ridges are understood to be axially adjacent ridges.

[0021] In yet another embodiment, the radial thickness of the sealant layer between two adjacent raised portions is, on average, in the range of 2 mm to 6 mm. In particular, the surface of the sealant may have a certain roughness resulting from the manufacturing method, such as the application of sealant strips.

[0022] In still other embodiments, i) the radial thickness of the sealant layer at the middle between two adjacent ridges (or the average of the radial thicknesses of the sealant between two adjacent ridges), and ii) the maximum radial thickness of one of the adjacent ridges, have a difference of at least 0.5 mm, preferably at least 0.8 mm, more preferably at least 1 mm, still more preferably at least 1.5 mm. In addition or alternatively, the difference may be at most 3 mm, preferably at most 2 mm, or at most 1.6 mm. When two adjacent ridges have different maximum radial thicknesses, the ridge having the smaller maximum radial thickness is considered here.

[0023] In still other embodiments, the sealant layer extends over at least 90% of the width of the tread portion, i.e., the tread measured in the axial direction of the tire. In still other embodiments, the tire includes a belt portion below the tread portion in the radial direction, the belt portion includes a plurality of belt plies arranged one above the other in the radial direction, and the sealant layer extends over at least 95% of the width, measured in the axial direction, of the largest belt ply in the axial direction.

[0024] In still other embodiments, the radial thickness of one of the ridges of two adjacent ridges, measured from the inner surface of the tire (e.g., inner liner) to the innermost surface in the radial direction or the tip of each ridge, is one or both of the following. (i) It is at least 15% greater, preferably at least 20% greater, than the radial thickness of the sealant layer at the middle between two adjacent ridges or the average radial thickness between these adjacent ridges. (ii) It is at most 100% greater, preferably at most 50% greater, than the radial thickness of the sealant layer at the center between two adjacent ridges or the average radial thickness of the sealant layer between the adjacent ridges. In particular, very thick regions of the sealant may not be very desirable even at the positions of the grooves.

[0025] For example, the radial thickness of the raised portion can be 15% to 100%, 20% to 90%, 30% to 80%, or 40% to 70% greater than the radial thickness of the sealant layer at the middle between two adjacent raised portions, or the average radial thickness between these adjacent raised portions.

[0026] In still another embodiment, the sealant layer (i) an axially adjacent sealant strip that extends basically circumferentially along the inner surface of the tire (e.g., on the inner liner of the tire) about the axis of the tire (e.g., at an angle of 0° to 0.5° or 0° with respect to the equatorial plane of the tire) (ii) one or more sealant strips wound spirally along the inner surface of the tire, e.g., the inner liner, about the axis of the tire (e.g., at an angle of less than 5° or even less than 2° with respect to the equatorial plane of the tire) and includes one of them.

[0027] In particular, such a sealant layer can be efficiently attached to the tire after the tire is cured.

[0028] In still another embodiment, the sealant strip forms a region radially below the raised portion and / or the circumferential ribs or rows of tread blocks of the sealant layer, and the sealant strip is optionally one or both of the following. - In the region radially below the circumferential groove, it is thicker radially than the region radially below the row of circumferential ribs or tread blocks so as to form a raised portion in the sealant layer. <​​​Thus, sealant strips, or in other words, beads, can only be arranged so that they overlap each other vertically in the raised areas. Alternatively, the region between two adjacent raised areas may contain multiple layers of strips arranged radially vertically. In such cases, the raised areas can typically have more layers of sealant strips.

[0030] In other embodiments, the sealant strip may have, for example, one of the following cross-sections: basically rectangular, basically polygonal, basically circular, or basically elliptical.

[0031] In yet another embodiment, the maximum radial thickness of the sealant strip corresponds to the maximum radial thickness of the raised portion, thereby forming a raised portion in the sealant layer.

[0032] In yet another embodiment, the sealant layer includes a plurality of sealant strips having different radial thicknesses, such as strips having a radial height greater than the strips forming the raised portions, and strips having a radial height less than the strips forming the raised portions, so as to form regions of the sealant layer between the raised portions.

[0033] In yet another embodiment, the raised portion has an axial width in the radially upward direction of the raised portion that is in the range of 80% to 120%, preferably 90% to 110%, of the axial width of the bottom of each groove.

[0034] In other embodiments, each ridge is essentially centered in the axial direction with respect to the axial center of the bottom of each groove located radially above the ridge.

[0035] In yet another embodiment, the tread section comprises two shoulder sections and an intermediate, or central, section positioned axially between the two shoulder sections, with each shoulder section including a circumferential shoulder rib, or a circumferential row of shoulder tread blocks. In addition, or instead, the central section includes at least three circumferential ribs and at least four circumferential grooves. Each shoulder rib may optionally be demarcated by one of the at least four circumferential grooves, particularly the outermost circumferential groove in each axial direction. Such rib and groove arrangements are typically found in relatively wide high-performance tires, especially UHP summer tires.

[0036] In yet another embodiment, i) raised portions of the sealant layer and ii) regions of the sealant layer having a radial thickness less than the radial thickness of the raised portions are alternately located along the axial direction of the tire. Preferably, the tire has at least three such regions and four such raised portions that are alternately arranged along the axial direction.

[0037] In one embodiment, the sealant layer has at least three raised portions formed between adjacent regions of the sealant, having a radial thickness smaller than the raised portions when viewed in the axial direction. The region between two axially adjacent raised portions of the sealant may also be generally described as a valley in the sealant layer.

[0038] In yet another embodiment, the region of the sealant layer having a radial thickness less than the radial thickness of the raised portion has an axial width in the radially upward direction, within the range of 60% to 120% of the radially outermost surface of each row of each rib or tread block.

[0039] In further embodiments, the sealant is one or more of the following: butyl rubber compositions, polyisoprene compositions, natural rubber compositions, polyurethane compositions, polybutene compositions, emulsion styrene-butadiene rubber compositions, EPDM compositions, and silicone compositions. For example, the sealant may be a blend of butyl rubber and polyisobutylene, as described in U.S. Patent No. 4,895,610. In other embodiments, the sealant may consist of a foamed solid containing foamed graphene structures and microspheres, as described in U.S. Patent No. 9,802,446. In other embodiments, the sealant composition may consist of at least one non-halogenated butyl rubber and 2,2'-dibenzamide-disulfide diphenyl, and the sealant composition has a viscosity that allows the sealant composition to be incorporated into the tire during the tire assembly process, and can be reduced to a lower viscosity so that the reduced sealant composition flows into and seals the tire puncture hole. This sealant composition is described in detail in U.S. Patent No. 8,360,122.

[0040] In other embodiments, a foamed material (i.e., a foamed material such as a circumferentially extending foamed strip) is attached to the radially inner surfaces of at least two adjacent ridges, thereby forming at least one air cavity between the adjacent ridges, the radially outer surface of the foamed material (e.g., the foamed strip), and the surface of the sealant layer between the adjacent ridges. In particular, the presence of a foamed material, such as a foamed block or a circumferentially extending foamed strip on the sealant layer, has been found to adversely affect the flow properties and / or sealant properties of the sealant in the event of a puncture. Furthermore, the presence of foam results in a reduction in thermal conductivity toward the tire cavity, and therefore a reduction in the potential for heat generation. Attaching the foamed material (such as a block or a circumferentially extending strip) to adjacent ridges helps to mitigate the aforementioned drawbacks.

[0041] In other embodiments, multiple foam blocks are arranged along the circumferential direction of the tire.

[0042] In yet another embodiment, the foam member is at least one foam strip extending continuously or discontinuously along a circumferential length corresponding to at least 50%, preferably at least 80%, of the inner circumference of the tire as measured along the inner surface at the axial center of the tire.

[0043] In yet another embodiment, the foam strip extends around the (central) axis of the tire.

[0044] In further embodiments, the axial width of the foam member (e.g., foam block or foam strip) is within the range of 20% to 50% of the maximum axial width of the sealant layer. The tire may have multiple foam members, such as the strips or blocks. In particular, it may be desirable to limit the axial width of the foam member to avoid unnecessary heat generation in the area of ​​the tire to which the foam member is attached. Generally, the foam member, especially the foam strip, may have a polygonal, for example, rectangular cross-section in some, but not limited, examples.

[0045] In yet another embodiment, the foam member has an axial width greater than the distance between two adjacent raised portions to which the foam member is attached.

[0046] In yet another embodiment, the foam member has a radially outer portion attached to two adjacent ridges or a radially inner portion having an axial width greater than the outermost surface. Such embodiments result in a relatively large volume of foam with a limited surface area adjacent to the sealant layer.

[0047] In other embodiments, the axial width of each raised portion is less than 50% of the axial width of the foamed material, such as the circumferential foamed strip, preferably less than 30%, and more preferably less than 20%.

[0048] In yet another embodiment, the foamed member, in particular the strip or block, does not include a coating or foil facing the sealant layer.

[0049] In other embodiments, the foamed material may be a noise attenuating material, a porous material, a polymer foam, a polyurethane foam, or 0.01 g / cm³. 3 From 1 g / cm³ 3 It comprises (or consists of) one or more materials having densities within the range. The terms damping and damping are used interchangeably herein.

[0050] In other embodiments, the foamed member comprises or consists of one or more of the following: porous materials and / or polyurethane foams (e.g., polyether-urethane, polyester-urethane), melamine foams, polypropylene foams, foamed rubbers (e.g., EPDM, neoprene foams), natural material foams (e.g., cellulose, chitosan foams), and nonwovens (e.g., felts made of meltblown, spunlaid or electrospun fibers, or natural fibers of polyester, polyamide, PE, PET, PP, cellulose, cotton, wool or silk). In addition, or instead, the foamed member comprises or consists of one or more of the following: polyurethane foams, polyethylene foams, foamed rubbers, etc. Suitable polyurethane foams are usually formed by polymerization of diisocyanates and polyols in the presence of a suitable foaming agent. In the implementation of the present invention, a wide variety of rubber foams can be used, with natural rubber, synthetic polyisoprene rubber, polybutadiene rubber, nitrile rubber, and styrene-butadiene rubber foams being commonly used. Such foamed rubber is typically formed by foaming natural or synthetic rubber latex with a chemical foaming agent. The chemical foaming agent would typically be an azo compound such as azodicarbonamide, a hydrazine compound, a carbazide, a tetrazole, a nitroso compound, and / or a carbonate, such as sodium bicarbonate.

[0051] In yet another embodiment, one or more foam strips are arranged circumferentially (preferably basically parallel). By providing multiple strips, the size of the continuous area covered by the noise damping material can be reduced, and thus the heat generation in the tire radially above the strips can be reduced.

[0052] In other embodiments, the foamed member is formed from an open-cell foam. Preferably, such a material contains 55% to 95% (or preferably 60% to 90%) open cells (of the total cells). An open cell can be understood as a cell having at least one opening. In other words, an open cell is not completely closed, i.e., not completely surrounded by a cell wall. Closed-cell foams do not fall within the above range, as most of the cells in this type of foam are closed. Completely or nearly completely mesh-like foams do not fall within this range either, as they have almost no walls and rather form an open lattice. Whether a cell is open (i.e., closed) can be determined, for example, by optical microscopy, scanning electron microscopy, or NMR. The size of the cells can typically range from 10 μm to 1 mm (maximum diameter).

[0053] In other embodiments, foam is adapted and / or used to attenuate tire cavity noise, particularly in the range of 100 Hz to 300 Hz, or 100 Hz to 200 Hz, or 200 Hz to 300 Hz. As described herein, the term tire cavity is, in particular, a volumetric portion enclosed by the inner surface of the tire (or the inner liner, if one exists) and closed by a (virtual) ring-shaped circumferential surface that contacts the innermost radial edges of both bead portions, when not attached to anything and not inflated.

[0054] In yet another embodiment, the foamed member is (directly) bonded to the sealant. In other words, the boundary between the sealant and the foamed member does not contain any additional adhesive or tack. Rather, it is the tackiness of the sealant that holds the foamed member in place.

[0055] In another aspect of the present invention, a method for manufacturing a pneumatic tire, preferably according to one or more of the embodiments or examples described above, is provided, a) Providing a non-hardened pneumatic tire comprising a tread portion, two optionally provided bead portions, and two sidewalls connecting each bead portion to the tread portion, wherein the tread portion has a plurality of circumferential grooves; b) A step to harden the tires, c) The step of forming a sealant layer on the inner surface of a hardened tire (e.g., the inner liner) by attaching one or more sealant strips to the inner surface, thereby forming raised portions in the sealant layer in the region radially below (i.e., radially inward) of the circumferential grooves of the tread, d) the step of attaching at least one foam member to the radially innermost portion of two adjacent raised sections, and one or more of the above steps.

[0056] In one embodiment, the sealant layer is formed by spirally attaching one or more sealant strips around the axle of the tire and along the inner surface of the tire.

[0057] In other embodiments, the step of forming a sealant layer includes rotating the tire about its axis of rotation and pushing the sealant strip onto the rotating inner surface of the tire.

[0058] In yet another embodiment, the strip is extruded by an extruder head and / or die that is axially movable or moved relative to the tire while the sealant strip is being extruded. As the tire rotates, the circumferential or helical strip may adhere to the inner surface of the tire.

[0059] In other embodiments, the sealant layer is formed by attaching (simultaneously or sequentially) a plurality of axially adjacent sealant strips that extend circumferentially along the inner surface of the tire around the tire axle.

[0060] In yet another embodiment, the strip is extruded or attached to a greater thickness when forming the raised portion.

[0061] In yet another embodiment, multiple layers of the strip (particularly two or three layers) are arranged so as to overlap each other vertically, at least in the raised portions.

[0062] In yet another embodiment, the sealant strip has an axial width in the range of 2 mm to 15 mm, preferably 5 mm to 12 mm, and more preferably 7.5 mm to 12 mm or 8 mm to 15 mm.

[0063] In yet another embodiment, the greater thickness of the sealant in the raised areas is achieved by one or more of the following: extruding the sealant strip at a higher speed than in areas with a smaller radial thickness; extruding the sealant strip at a higher pressure than in areas with a smaller radial thickness; using an extruder die with a larger outlet diameter; using an extruder die with an adjustable, particularly expandable, outlet diameter; and rotating the tire more slowly around its axis of rotation when extruding the strip in the raised areas than when extruding the strip in areas with a smaller radial thickness.

[0064] The application of sealant strips, as described above, is particularly interesting in combination with foam strips, or in other words, noise-attenuating foam strips that extend essentially in the circumferential direction.

[0065] In yet another embodiment, the method further comprises the steps of: applying a first layer of one or more sealant strips over the entire axial width of the sealant layer; and applying at least a second layer of one or more sealant strips (discontinuously or continuously), wherein the second layer of sealant strips forms a raised portion of the sealant.

[0066] In one embodiment, the tire is a passenger car tire, a truck tire, or a bus tire.

[0067] In other embodiments, the tire has a width of at least 225, preferably at least 245.

[0068] In yet another embodiment, the tires are summer tires.

[0069] In other embodiments, the tire is an all-season tire and optionally displays a 3-Peak Mountain Snowflake symbol (3PMSF symbol) on at least one sidewall.

[0070] In other embodiments, the tire is a winter tire that displays a 3-peak mountain snowflake symbol (3PMSF symbol) on at least one sidewall.

[0071] In general, features of different aspects and embodiments of the present invention can be combined with each other, in addition to the features described below. [Brief explanation of the drawing]

[0072] [Figure 1] A schematic cross-sectional view of a conventional tire including a sealant layer is shown. [Figure 2]A schematic cross-sectional view of one embodiment of a sealant tire according to the present invention is shown. [Figure 3] A schematic cross-sectional view of a conventional tire, including a foaming strip attached to the sealant layer, is shown. [Figure 4] A schematic cross-sectional view of a noise-damping sealant tire according to one embodiment of the present invention is shown. [Modes for carrying out the invention]

[0073] The structure, function, and advantages of the present invention will become clearer upon consideration of the following description in conjunction with the accompanying drawings.

[0074] Figure 1 is a schematic cross-sectional view of a conventional tire 1'. In this example, tire 1' has a tread portion 10, two bead portions 3, and two sidewalls 2 that join the axial outer edges of the tread portion 10 to the respective bead portions 3. The tread portion 10 has a plurality of circumferential grooves 9 and ribs 8. Such a pneumatic tire structure is generally known in the tire industry. Tire 1' has an inner surface defining a tire cavity 6. A sealant layer 5' is provided on the inner surface of tire 1' in the region opposite to the tread portion 10. The thickness of the sealant layer 5' is essentially constant across the axial width and outer circumference of tire 1'. For ease of understanding, reference numerals 2, 3, 6, 8, 9, and 10 are used in the description of Figures 2-4 to refer to the same components described below.

[0075] Figure 2 shows a tire 1 according to a first embodiment of the present invention. Similar to the tire 1' shown in Figure 1, the tire 1 has a sidewall 2, a bead portion 3, a tread portion 10, a tire cavity 6 arbitrarily separated by the inner liner of the tire 1, a circumferential groove 9 (i.e., in other words, a circumferential main groove), and a circumferential rib 8.

[0076] The sealant layer 5 according to the embodiment shown in Figure 2 extends along the inner surface of the tire 1 in the circumferential direction c and the axial direction a. The sealant layer 5 has four raised portions 19, each of which is located radially below the groove 9 in the axial direction. In other words, the sealant layer 5 has a portion that is thicker in the axial position of the groove 9 than the region 18 located radially below the rib 8, where the radial thickness is smaller. As a result, the thicker sealant in the radially inner region of the groove improves the sealing performance of the tire 1 in the region where the tread rubber material is relatively thin compared to the region where the tread rubber material is relatively thick in the axial position of the rib 8. This configuration strikes a good balance between the sealing properties of the sealant and weight impact. In particular, a large amount of sealant can increase the weight of the tire 1, which may lead to a decrease in ride comfort and handling characteristics. Furthermore, as shown in Figure 1, it is more cost-effective compared to tire 1'. Furthermore, having a thinner sealant layer in the radially downward region of the rib 8 improves thermal conductivity and / or avoids heat generation in these regions, particularly for improved high-speed performance and frequent cornering operations. It should be noted that the relative thickness of the illustrated ridges 19, or in other words, the radially inward projections or ridges of the sealant layer, is schematically shown in Figure 1. Preferred absolute and relative thicknesses are described herein. In non-limiting embodiments, the thickness of the sealant layer 5 is approximately 3.6 mm in the region 18 between the ridges 19, while the maximum thickness of the sealant layer 5 in the ridges 19 is approximately 4.5 mm.

[0077] For clarity, the axial direction a, circumferential direction c, and radial direction r are shown in Figure 2, as is commonly used in descriptions of tire geometry. The term "direction" is not limited to specific orientations unless otherwise specified herein. The axial direction a can be understood as the direction parallel to the axis of rotation of tire 1. The circumferential direction c is concentric with the axis of rotation of tire 1, and the radial direction r extends radially from the axis of rotation, as is commonly understood in the tire industry.

[0078] Figure 3 shows a conventional tire 1" having members 2, 3, 6, 8, 9, and 10, as previously described in relation to Figures 1 and 2, but including a sealant layer 5" supporting a noise damping member 7". Such a noise damping member 7" may be used to dampen or reduce noise generated in the tire cavity 6 during driving. A drawback of such a configuration is the relatively large amount of heat generated radially above the noise damping member 7" acting together with the sealant layer 5" as an insulator. This can adversely affect the performance and / or stability of the tire. Furthermore, it has been found that such a noise damping member 7" can adversely affect the performance of the sealant by hindering the free flow of sealant to puncture holes in the tread. Therefore, such a configuration typically requires a relatively thick sealant layer 5" which further adversely affects cost, weight, and thermal conductivity, and thus the performance of the tire.

[0079] In a preferred embodiment of the present invention, as shown in Figure 4, using the same reference numerals as previously described in the drawings, a foamed material, such as an adhesive circumferential foam strip 7, is attached to the sealant layer 5 within the structure of the tire 11. In a non-limiting example, the sealant layer 5 has the same shape as in the embodiment of Figure 2, thereby having a raised portion 19 radially below the groove 9 and a region 18 radially below the rib 8 where the sealant is thinner. The foam strip 7 is attached to the two raised portions 19 so as to form an air cavity 16 between the sealant layer 5 and the foam strip 7. Thus, the foam strip 7 does not directly contact the sealant layer 5 over its entire axial width. Heat generation is reduced in the region below the foam strip and in the rib region. Furthermore, because the sealant is relatively thicker where it contacts the foam strip 7, and because of the air cavity 16 in the region covered by the foam strip 7 between two adjacent raised portions 19, the sealant is reliably able to flow into the puncture hole radially above the foam strip 7. Furthermore, safety is improved by the relatively large thickness of the sealant in the radially downward direction of the circumferential main groove 9. To reduce the overall weight and improve thermal conductivity, the sealant is stored in region 18.

[0080] In this embodiment, a foam strip 7 was described as an example of a foam member, but it is also possible to arrange multiple foam strip segments in a row in the circumferential direction, or to arrange multiple foam blocks along the circumferential direction and attach them to at least two adjacent raised portions in the axial direction.

[0081] The circumferential foam strip 7 is preferably positioned at the axial center of the tire 11, or in other words, along the equatorial plane EP of the tire 11, as shown in Figure 4. Such an arrangement improves the balance of the tire.

Claims

1. (i) a tread portion (10) having circumferential grooves (9) and (ii) rows of circumferential ribs (8) or tread blocks, an inner surface defining a tire cavity (6), and a sealant layer (5) that at least partially covers the inner surface radially below the tread portion (10) within the tire cavity (6), wherein the sealant layer (5) includes raised sealant portions (19), the raised sealant portions (19) are provided radially below each of at least two of the circumferential grooves (9), and the sealant layer (5) has a radial thickness greater in the raised portions (19) than in the radially below region (18) of the rows of circumferential ribs (8) or tread blocks. Each of the aforementioned raised portions (19) has an axial width within the range of 70% to 130% of the axial width of the bottom of the circumferential groove (9) located radially above each of the aforementioned raised portions (19). At least one foam member (7) is attached to the radially inner surface of at least two axially adjacent raised portions (19), thereby forming at least one air cavity (16) between the axially adjacent raised portions (19), the radially outer surface of the foam member (7), and the radially inner surface of the sealant layer (5) between the axially adjacent raised portions (19). The pneumatic tire (1, 11) is characterized in that the foam member (7) is optionally a foam strip extending in the circumferential direction (c) along a circumferential length corresponding to at least 50% of the inner circumference of the tire (11), measured along the inner surface at the axial center of the tire (11).

2. The pneumatic tire according to claim 1, wherein the foam member (7) is optionally a foam strip extending in the circumferential direction (c) along a circumferential length corresponding to at least 80% of the inner circumference of the tire (11), measured along the inner surface at the axial center of the tire (11).

3. The pneumatic tire according to claim 1 or 2, characterized in that the radial thickness of one of two adjacent raised portions (19), measured from the inner surface of the tire (1, 11) to the innermost surface in the radial direction of each raised portion (19), is at least 15% greater than the radial thickness of the sealant layer (5) in the middle between the two adjacent raised portions (19), or at most 100% greater than the radial thickness of the sealant layer (5) in the middle between the two adjacent raised portions (19), or both.

4. The pneumatic tire according to any one of claims 1 to 3, characterized in that the tire (1, 11) includes at least three circumferential grooves (8) and at least four rows of circumferential ribs (9) or tread blocks.

5. The pneumatic tire according to any one of claims 1 to 4, characterized in that the raised portion (19) of the sealant is provided radially below each of the circumferential grooves (9).

6. A pneumatic tire according to any one of claims 1 to 5, characterized in that the maximum radial thickness of the raised portion (19), measured from the inner surface of the tire (1, 11) to the innermost surface in the radial direction of each raised portion (19), is in the range of 3 mm to 9 mm, and / or the radial thickness of the sealant layer (5) in the middle between two adjacent raised portions (19) is in the range of 2 mm to 6 mm.

7. i) the difference between the radial thickness of the sealant layer (5) in the middle between two adjacent raised portions (19) and ii) the maximum radial thickness of one of the adjacent raised portions (19) is at least 0.5 mm, and / or The pneumatic tire according to any one of claims 1 to 6, characterized in that the sealant layer (5) extends axially over at least 90% of the width of the tread portion (10).

8. The pneumatic tire according to any one of claims 1 to 7, characterized in that the sealant agent comprises one or more of the following: a butyl rubber composition, a polyisoprene composition, a natural rubber composition, a polyurethane composition, a polybutene composition, an emulsion styrene-butadiene rubber composition, an EPDM composition, and a silicone composition.

9. The sealant layer is (i) A sealant strip that extends circumferentially along the inner surface of the tire (1, 11) with respect to the axis of the tire (1, 11), and is adjacent to the axial surface of the tire (1, 11), (ii) One or more sealant strips wound spirally along the inner surface of the tire (1, 11) with respect to the axle of the tire (1, 11), A pneumatic tire according to any one of claims 1 to 8, characterized in that it includes one of the following.

10. The sealant strip forms the raised portion (19) and the region of the sealant layer (5) radially below the circumferential rib (9) or the row of tread blocks, At least a number of the sealant strips are In order to form the raised portion in the sealant layer (5), the region radially below the circumferential groove (8) is radially thicker than the region (18) radially below the circumferential rib (9) or the row of tread blocks, The sealant layer (5) is arranged so as to form the raised portion (19) on it, with the layers overlapping each other vertically. The pneumatic tire according to claim 9, characterized by having one or both of the following.

11. The tread portion (10) has two shoulder portions and a central portion between the two shoulder portions in the axial direction, each of the shoulder portions includes a row of circumferential shoulder ribs or shoulder tread blocks, the central portion includes at least three circumferential ribs and at least four circumferential grooves, and each of the shoulder ribs is defined by one of the at least four circumferential grooves. The raised portion (19) of the sealant layer (5) and the region (18) of the sealant layer having a radial thickness smaller than the radial thickness of the raised portion (19) are alternately located along the axial direction (a) of the tire (1, 11). The pneumatic tire according to any one of claims 1 to 10, characterized in that the region (18) of the sealant layer (5), having a radial thickness smaller than the radial thickness of the raised portion (19), has an axial width in the range of 60% to 120% of the radially outermost surface of each row of ribs or tread blocks radially upward.

12. The axial width of the foamed member (7) is within the range of 20% to 50% of the maximum axial width of the sealant layer (5). The pneumatic tire according to any one of claims 1 to 11, characterized in that the foam member (7) does not contain a coating or foil facing the sealant layer (5).

13. The foamed member (7) Noise attenuation material and Polymer foam material, Polyurethane foam material, Strip shape and, Density is 0.01 g / cm³ 3 From 1 g / cm³ 3 Materials within the range, A pneumatic tire according to any one of claims 1 to 12, characterized by including one or more of the following.

14. A method for manufacturing a tire according to any one of claims 1 to 13, The step of hardening the tire (1,11), The steps include: forming a sealant layer (5) on the inner surface of a hardened tire (1, 11) by attaching one or more sealant strips to the inner surface, and forming a raised portion (19) in the sealant layer (5) in the region radially below the circumferential groove (9) of the tire tread portion (10); The optional step of attaching at least one foam member (7) to the innermost radial portion of two adjacent raised portions (19), A method that includes this.

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