JP2021130348A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire configured so that a sealant is prevented from flowing during travelling, while making a sealant layer exert excellent sealability.SOLUTION: The pneumatic tire comprises a sealant layer 10 made of an adhesive sealant material on an inner surface of a tread part 1, where a thickness T1 of the tread part 1 and a thickness S1 of the sealant layer 10, in a tire equator position satisfy a relation of 0.15<S1/T1<0.35, and a thickness T2 of the tread part 1 and a thickness S2 of the sealant layer 10, in an end part position of a belt layer 7 satisfy a relation of 0.20<S2/T2<0.40.SELECTED DRAWING: Figure 1

Description

The present invention relates to a self-sealing type pneumatic tire provided with a sealant layer on the inner surface of the tire.

In a pneumatic tire, it has been proposed to provide a sealant layer inside the inner liner layer in the tread portion in the tire radial direction (see, for example, Patent Document 1). In such a pneumatic tire, when a foreign substance such as a nail pierces the tread portion, the sealant material constituting the sealant layer flows into the through hole to suppress a decrease in air pressure and maintain running. Will be possible.

In the self-sealing type pneumatic tire described above, if the sealant material has a low viscosity, the sealant material can be expected to improve the sealing property in that the sealant material easily flows into the through hole. If the sealant material flows toward the tire center side due to the influence, and as a result, the through hole deviates from the tire center region, the sealant material may be insufficient and sufficient sealing property may not be obtained. On the other hand, if the viscosity of the sealant material is high, the above-mentioned flow of the sealant material can be prevented, but the sealant material is less likely to flow into the through holes, and the sealing property may be deteriorated. Therefore, when providing the sealant layer on the inner surface of the tire, it is required to balance the suppression of the flow of the sealant material with running and the securing of good sealing property in a well-balanced manner.

Japanese Unexamined Patent Publication No. 2006-152110

An object of the present invention is a pneumatic tire provided with a sealant layer on the inner surface of the tire, and it is possible to prevent the sealant from flowing during traveling while exhibiting good sealing performance by the sealant layer. The purpose is to provide pneumatic tires.

The pneumatic tire of the present invention that achieves the above object has a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a tire of these sidewall portions. A pair of bead portions arranged inside in the outer radial direction, a carcass layer mounted between the pair of bead portions, and at least one layer of belt arranged on the outer peripheral side of the carcass layer in the tread portion. In a pneumatic tire having a reinforcing layer including a layer and at least an inner surface of the tread portion provided with a sealant layer made of an adhesive sealant material, the thickness T1 of the tread portion at the tire equatorial position and the sealant layer. The thickness S1 of the above satisfies the relationship of 0.15 <S1 / T1 <0.35, and the thickness T2 of the tread portion and the thickness S2 of the sealant layer at the end position of the belt layer are 0.20. It is characterized in that the relationship of <S2 / T2 <0.40 is satisfied.

The pneumatic tire of the present invention exhibits a sealing property by providing the sealant layer as described above, and at that time, the thickness of the sealant layer is treaded at each part (the position of the equator of the tire and the position of the end of the belt layer). Since it is set in an appropriate range with respect to the thickness of the portion, it is possible to suppress the flow of the sealant during traveling without impairing the sealing property. That is, the thickness of the tread portion affects the deformability of the tire, and the more easily the tire is deformed, the more easily the sealant flows during running. By setting it in an appropriate range, it becomes possible to suppress the flow during running.

In the present invention, regarding the tread rubber arranged on the outer peripheral side of the reinforcing layer, when the thickness of the tread rubber at the tire equatorial position is T3 and the thickness of the tread rubber at the end position of the belt layer is T4, the tread rubber The thickness T3 and the thickness S1 of the sealant layer satisfy the relationship of 0.20 <S1 / T3 <0.40, and the thickness T4 of the tread rubber and the thickness S2 of the sealant layer are 0.25 <S2 /. It is preferable to satisfy the relationship of T4 <0.45. As a result, the ratio of the thickness of the tread portion (tread rubber) to the thickness of the sealant layer is set in a more appropriate range, which is advantageous for suppressing the flow during running while maintaining the sealing property.

In the present invention, it is preferable that the thickness T4 of the tread rubber and the loss tangent tan δ (60 ° C.) of the tread rubber at 60 ° C. satisfy the relationship of T4 × tan δ (60 ° C.) ≦ 5. With such a setting, the heat generation of the tread portion can be suppressed, and the heat generation of the sealant layer in contact with the tread portion can also be suppressed accordingly, which is advantageous in suppressing the flow of the sealant.

In the present invention, the width Ws of the sealant layer is equal to or greater than the width Wb of the belt layer, and the outside of the tire is measured at the end position of the belt layer when the normal internal pressure is applied and the sealant layer is placed vertically on a flat surface. Regarding the vertical distance between the surface and the flat surface, it is preferable that the difference L1-L2 between the vertical distance L1 when no load is applied and the vertical distance L2 when a normal load is applied is within 15 mm. As a result, the amount of deformation of the tire at the end position of the belt layer can be suppressed to be small, and the flow of the sealant due to the deformation of the tire can be suppressed.

In the present invention, it is preferable that the adhesive sealant material is crosslinked. By forming the sealant layer with a pre-crosslinked adhesive sealant material in this way, deformation of the sealant material in the tire width direction and the tire circumferential direction when the sealant layer (sealant material) is pressed against the inner surface of the tire is prevented. Can be prevented.

Further, in the present invention, when measuring the above-mentioned vertical distances L1 and L2, the tire is rim-assembled on a regular rim and the above-mentioned internal pressure is applied. A "regular rim" is a rim defined for each tire in a standard system including a standard on which a tire is based. For example, a standard rim for JATTA, a "Design Rim" for TRA, or ETRTO. If so, it is set to "Measuring Rim". "Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which the tire is based. If it is JATTA, it is the maximum air pressure, and if it is TRA, it is the table "TIRE ROAD LIMITED AT VARIOUS". The maximum value described in "COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO, but 180 kPa when the tires are for passenger cars. "Regular load" is the load defined for each tire in the standard system including the standard on which the tire is based. If it is JATTA, it is the maximum load capacity, and if it is TRA, it is the table "TIRE ROAD LIMITED AT VARIOUS". The maximum value described in "COLD INFLATION PRESSURES" is "LOAD CAPACITY" in the case of ETRTO, but when the tire is for a passenger car, the load is equivalent to 88% of the above load.

It is a meridian cross-sectional view which shows an example of the pneumatic tire of this invention. It is explanatory drawing which enlarges and shows the vicinity of the end position of the belt layer of the pneumatic tire of this invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, for example, the pneumatic tire of the present invention (self-sealing type pneumatic tire) is arranged on a tread portion 1 extending in the tire circumferential direction to form an annular shape and on both sides of the tread portion 1. It includes a pair of sidewall portions 2 and a pair of bead portions 3 arranged inside the sidewall portion 2 in the tire radial direction. In FIG. 1, the reference numeral CL indicates the tire equator. Although FIG. 1 is a cross-sectional view of the meridian, the tread portion 1, the sidewall portion 2, and the bead portion 3 each extend in the tire circumferential direction to form an annular shape, whereby the pneumatic tire is formed. The toroidal basic structure of is constructed. Further, unless otherwise specified, other tire components in the meridian cross-sectional view extend in the tire circumferential direction to form an annular shape.

In the example of FIG. 1, a carcass layer 4 is mounted between the pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inside to the outside of the vehicle around the bead core 5 and the bead filler 6 arranged in each bead portion 3. The bead filler 6 is arranged on the outer peripheral side of the bead core 5, and is wrapped by a main body portion and a folded portion of the carcass layer.

A plurality of layers (two layers in FIG. 1) of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. Among these plurality of belt layers 7, the layer having the smallest belt width is referred to as the minimum belt layer 7a, and the layer having the largest belt width is referred to as the maximum belt layer 7b. Each belt layer 7 includes a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to intersect each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in the range of, for example, 10 ° to 40 °. A belt reinforcing layer 8 is provided on the outer peripheral side of the belt layer 7 in the tread portion 1. In the illustrated example, two belt reinforcing layers 8 are provided, one is a full cover layer covering the entire width of the belt layer 7, and the other is an edge cover layer arranged on the outer peripheral side of the full cover layer and covering only the end portion of the belt layer 7. ing. The belt reinforcing layer 8 includes an organic fiber cord oriented in the tire circumferential direction, and the angle of the organic fiber cord with respect to the tire circumferential direction is set to, for example, 0 ° to 5 °.

In the tread portion 1, the tread rubber layer R1 is arranged on the outer peripheral side of the above-mentioned tire constituent members (carcass layer 4, belt layer 7, belt cover layer 8). The tread rubber layer R1 may have a structure in which two types of rubber layers (cap tread layer and under tread layer) having different physical properties are laminated in the tire radial direction. A side rubber layer R2 is arranged on the outer peripheral side (outside in the tire width direction) of the carcass layer 4 in the sidewall portion 2, and a rim cushion rubber layer R3 is arranged on the outer peripheral side (outside in the tire width direction) of the carcass layer 4 in the bead portion 3. Have been placed.

An inner liner layer 9 is provided on the inner surface of the tire along the carcass layer 4. The inner liner layer 9 is a layer for preventing the air filled in the tire from permeating to the outside of the tire. The inner liner layer 9 is composed of, for example, a rubber composition mainly composed of butyl rubber having an air permeation prevention property. Alternatively, it may be composed of a resin layer having a thermoplastic resin as a matrix. In the case of the resin layer, the elastomer component may be dispersed in the matrix of the thermoplastic resin.

The present invention relates to the thickness of the sealant layer 10 and the tread portion 1, which will be described later, provided on the inner surface of such a pneumatic tire. Therefore, as long as the pneumatic tire of the present invention is provided with the sealant layer 10 described later, the basic structure excluding the characteristics relating to the thickness of the tread portion 1 described later is not limited to the above-mentioned structure. The sealant layer 10 is attached to the inner surface of a pneumatic tire having the above-mentioned basic structure. For example, when a foreign substance such as a nail pierces the tread portion 1, the sealant layer 10 is inserted into the through hole. By inflowing the sealant material constituting the tire and sealing the through hole, it is possible to suppress the decrease in air pressure and maintain the running.

As shown in FIG. 1, a sealant layer 10 is provided inside the inner liner layer 9 in the tread portion 1 in the tire radial direction. The sealant layer 10 is provided on the inner surface of the tire corresponding to a region where foreign matter such as a nail may pierce during traveling, that is, a ground contact region of the tread portion 1. Preferably, the width Ws of the sealant layer 10 is equal to or larger than the width Wb of the belt layer 7 (the width of the widest belt layer (maximum belt layer 7b in the case of the illustrated example)). Further, the amount w of the sealant layer 10 protruding from the normal line of the carcass line passing through the widthwise end of the widest belt layer (maximum belt layer 7b in the case of the illustrated example) is preferably 20 mm or less.

As shown in FIG. 1, the thickness of the tread portion 1 at the position of the tire equatorial line CL is T1, the thickness of the sealant layer 10 at the position of the tire equatorial line CL is S1, and the thickness of the tread portion 1 at the end position of the belt layer 7. Assuming that the thickness is T2 and the thickness of the sealant layer 10 at the end position of the belt layer 7 is S2, in the present invention, the thicknesses T1 and S1 satisfy the relationship of 0.15 <S1 / T1 <0.35, and The thicknesses T2 and S2 satisfy the relationship of 0.20 <S2 / T2 <0.40. By setting the thickness of the sealant layer 10 in each portion (the position of the tire equator CL and the end position of the belt layer 7) to an appropriate range with respect to the thickness of the tread portion 1 in this way, the sealing property is impaired. It is possible to suppress the flow of the sealant during running. That is, the thickness of the tread portion 1 affects the deformability of the tire, and the more easily the tire is deformed, the more easily the sealant flows during traveling. Therefore, the thickness of the tread portion 1 and the thickness of the sealant layer 10 By setting the ratio of to an appropriate range, it becomes possible to suppress the flow during running.

At this time, if the ratio S1 / T1 is 0.15 or less, the sealant layer 10 is too thin, and it becomes difficult to sufficiently secure the sealing property. When the ratio S1 / T1 is 0.35 or more, the sealant layer 10 is too thick, so that the weight of the sealant layer 10 (the amount of the sealant material used) increases, the flow tends to occur, and the uniformity decreases. Is a concern. When the ratio S2 / T2 is 0.20 or less, the sealant layer 10 is too thin, and it becomes difficult to sufficiently secure the sealing property. When the ratio S2 / T2 is 0.40 or more, the sealant layer 10 is too thick, so that the weight of the sealant layer 10 (the amount of the sealant material used) increases, the flow tends to occur, and the uniformity decreases. Is a concern.

Further, as shown in FIG. 1, regarding the tread rubber layer R1, the thickness of the tread rubber layer R1 at the position of the tire equatorial CL is T3, and the thickness of the tread rubber layer R1 at the end position of the belt layer 7 is T4. The thicknesses S1 and S2 of the above-mentioned sealant layer 10 have a relationship of 0.20 <S1 / T3 <0.40 and 0.25 <S2 / T4 <0.45 with respect to the thicknesses T3 and T4. It is preferable to meet. As a result, the ratio of the thickness of the tread portion 1 (tread rubber layer R1) to the thickness of the sealant layer 10 is set in a more appropriate range, which is advantageous for suppressing the flow during traveling while maintaining the sealing property. become.

At this time, if the ratio S1 / T3 is 0.20 or less, the sealant layer 10 is too thin, and it becomes difficult to sufficiently secure the sealing property. When the ratio S1 / T3 is 0.40 or more, the sealant layer 10 is too thick, so that the weight of the sealant layer 10 (the amount of the sealant material used) increases, the flow tends to occur, and the uniformity decreases. Is a concern. When the ratio S2 / T4 is 0.25 or less, the sealant layer 10 is too thin, and it becomes difficult to sufficiently secure the sealing property. When the ratio S2 / T4 is 0.45 or more, the sealant layer 10 is too thick, so that the weight of the sealant layer 10 (the amount of the sealant material used) increases, the flow tends to occur, and the uniformity decreases. Is a concern.

In the present invention, the thicknesses T1, T2, T3, T4, S1 and S2 are all measured along the normal of the carcass line (the contour line of the outer peripheral side of the carcass layer 4 in the meridian cross section). Specifically, the thicknesses T1, T3, and S1 are tread portions 1, which are measured along the normal line of the carcass line (which basically coincides with the tire equatorial CL) passing through the intersection of the carcass line and the tire equator CL, respectively. This is the thickness of the tread rubber layer R1 and the sealant layer 10. The thicknesses T2, T4, and S2 are the tread portion 1 and the tread rubber layer R1 measured along the normal line of the carcass line passing through the end portion of the widest belt layer 7 (the end portion of the maximum belt layer 7b), respectively. , The thickness of the sealant layer 10.

In the present invention, if the thickness of the sealant layer 10 and the ratio of the tread portion 1 (tread rubber layer R1) have the above-mentioned relationship, the thickness of the sealant layer 10 is not particularly limited, but in a general pneumatic tire, the thickness of the sealant layer 10 is not particularly limited. The thickness of the sealant layer 10 can be set to, for example, 0.5 mm to 5.0 mm. By having such a thickness, it is possible to suppress the flow of the sealant during running while ensuring good sealing performance. Further, the workability when the sealant layer 10 is attached to the inner surface of the tire is also improved. If the thickness of the sealant layer 10 is less than 0.5 mm, it becomes difficult to secure sufficient sealing properties. If the thickness of the sealant layer 10 exceeds 5.0 mm, the tire weight increases and the rolling resistance deteriorates. The thickness of the sealant layer 10 is an average thickness.

In the tread portion 1 of a general pneumatic tire, the thickness tends to gradually decrease from the tire equator CL toward the outside in the tire width direction. That is, the thicknesses T1, T2, T3, and T4 often have a relationship of T1> T2 and T3> T4. Therefore, in consideration of the change in the thickness of the tread portion 1 (tread rubber layer R1) in the width direction, in setting the relationship of the above-mentioned ratios S1 / T1, S2 / T2, S1 / T3, S2 / T4, It is preferable that the thickness of the sealant layer 10 is uniform over the entire tire width direction so as to satisfy the above range. By making the thickness of the sealant layer 10 uniform in this way, excellent sealing properties can be exhibited in the entire area in the tire width direction. On the other hand, even if the thickness of the sealant layer 10 is uniform, the above-mentioned ratio S1 / T1, S2 / T2, S1 / T3, S2 / T4 can be satisfied, so that the flow of the sealant is also effective. Can be suppressed.

The physical properties of the rubber constituting the tread rubber layer R1 (hereinafter referred to as tread rubber) are not particularly limited, but the product T4 × of the loss tangent tan δ (60 ° C.) of the tread rubber at 60 ° C. and the thickness T4 of the tread rubber layer R1. It is preferable that tan δ (60 ° C.) satisfies the relationship of T4 × tan δ (60 ° C.) ≦ 5. With such a setting, the heat generation of the tread portion 1 can be suppressed, and the heat generation of the sealant layer 10 in contact with the tread portion 1 can also be suppressed accordingly, which is advantageous in suppressing the flow of the sealant. When the product T4 × tan δ (60 ° C.) exceeds 5, the heat generating property of the tread portion 1 deteriorates and the above-mentioned effect cannot be expected. “Tan δ” is a value measured using a viscoelastic spectrometer under the conditions of a temperature of 60 ° C., an elongation deformation distortion rate of 10% ± 2%, and a frequency of 20 Hz in accordance with JIS K6394.

In a tire provided with the sealant layer 10, the smaller the deformation of the tire during traveling, the less the influence on the sealant layer 10 and the less the flow of the sealant is suppressed. In particular, it is preferable that the deformation of the tire is small near the end of the sealant layer 10. In the present invention, as described above, the end portion of the sealant layer 10 is arranged at a position beyond the end position of the belt layer 7, and the protrusion amount w is preferably 20 mm or less. Suppressing the deformation of the tire is effective in suppressing the flow of the sealant. Therefore, as shown in FIG. 2, the vertical distance between the tire outer surface and the flat surface measured at the end position of the belt layer 7 when the normal internal pressure is applied and the tire is placed vertically on the flat surface is as follows. It is preferable to set to. That is, when the vertical distance of the tire (solid line in the figure) when no load is applied is L1 and the vertical distance of the tire (broken line in the figure) when a normal load is applied is L2, the difference between them is L1-L2. Is preferably within 15 mm. By defining the vertical distances L1 and L2 in this way, the amount of deformation of the tire at the end position of the belt layer 7 can be suppressed to be small, and the flow of the sealant due to the deformation of the tire can be suppressed. .. At this time, if the difference L1-L2 exceeds 15 mm, the deformation at the end position of the belt layer 7 becomes large and the strain increases, so that the sealant may easily flow.

The sealant layer 10 can be formed by later attaching it to the inner surface of the vulcanized pneumatic tire. For example, the sealant layer 10 is formed by attaching a sheet-shaped sealant material over the entire circumference of the inner surface of the tire, or by spirally attaching a string-shaped or band-shaped sealant material to the inner surface of the tire. Can be formed. At that time, it is preferable to use a sealant material that is crosslinked. By using the sealant material crosslinked in advance in this way, it is possible to prevent the sealant material from being deformed in the tire width direction and the tire circumferential direction when the sealant layer 10 (sealant material) is pressed against the inner surface of the tire.

Hereinafter, the present invention will be further described with reference to Examples, but the scope of the present invention is not limited to these Examples.

In a pneumatic tire having a tire size of 235 / 40R18 and having the basic structure shown in FIG. 1 and having a sealant layer on the inner surface of the tread portion, the thickness S1 of the sealant layer relative to the thickness T1 of the tread portion at the tire equatorial position. Ratio S1 / T1, ratio of tread layer thickness S2 to tread thickness T2 at the end of the belt layer S2 / T2, ratio of tread rubber thickness T3 to sealant layer thickness S1 at the tire equatorial position S1 / T3, the ratio of the thickness of the sealant layer S2 to the thickness of the tread rubber T4 at the end position of the belt layer S2 / T4, the thickness of the tread rubber T4 and the loss of the tread rubber at 60 ° C. Table 1 shows the product T4 × tan δ (60 ° C.), the difference L1-L2 between the vertical distance L1 when no load is applied and the vertical distance L2 when a normal load is applied at the end position of the belt layer. The tires of Comparative Examples 1 to 8 and Examples 1 to 6 set as described above were manufactured.

In all the examples, the thicknesses T1, T2, T3, T4, S1 and S2 were measured along the normal of the carcass line (the contour line of the outer peripheral surface of the carcass layer in the meridian cross section). The loss tangent tan δ (60 ° C.) of the tread rubber at 60 ° C. is based on JIS K6394 under the conditions of a temperature of 60 ° C., an elongation deformation strain rate of 10% ± 2%, and a frequency of 20 Hz using a viscoelastic spectrometer. It is a measured value. The vertical distances L1 and L2 are the vertical distances between the outer surface of the tire and the flat surface measured under each load condition at the end position of the belt layer when the normal internal pressure is applied and the vehicle is placed vertically on the flat surface. ..

For these test tires, the sealability, uniformity, and fluidity during running were evaluated by the following test methods, and the results are also shown in Table 1.

Sealability Each test tire is assembled to a wheel with a rim size of 18 x 8.5J and mounted on a test vehicle, and a tread with a diameter of 4.0 mm is treaded under the conditions of initial air pressure of 250 kPa, load of 8.5 kN, and temperature of 23 ° C (room temperature). After driving into the part, the air pressure was measured after the tire was allowed to stand for 1 hour with the nail removed. The evaluation results are shown in the following four stages. If the evaluation result is "○" or "◎", it means that sufficient sealing property is exhibited, and if it is "◎", it means that particularly excellent sealing property is exhibited.
⊚: Air pressure after standing still is 240 kPa or more and 250 kPa or less ○: Air pressure after standing is 230 kPa or more and less than 240 kPa Δ: Air pressure after standing is 200 kPa or more and less than 230 kPa ×: Air pressure after standing is less than 200 kPa

Uniformity Each test tire was assembled on a wheel having a rim size of 18 × 8.5J, and the radial force variation (RFV) was measured by a uniformity measurement test device at an air pressure of 200 kPa. However, the measurement conditions conformed to the JASO standard. The obtained results are listed in the "Uniformity" column of Table 1 as an index with the value of Comparative Example 1 as 100. If the index value is "90" or more, it means that good uniformity can be maintained.

Sealant fluidity test The tire was assembled to a wheel with a rim size of 18 x 8.5J, mounted on a drum tester, and ran for 1 hour under the conditions of air pressure 220 kPa, load 8.5 kN, and running speed 80 km / h, and the sealant after running. The flow state of was investigated. The evaluation result is that a line of 5 mm grid ruled 20 x 40 squares is drawn on the surface of the sealant layer before running, the number of squares whose shape is distorted after running is counted, and no flow of the sealant is observed (distorted squares). The number of distorted cells is 0) is indicated by "○", the case where the number of distorted cells is less than 1/4 of the total is indicated by "△", and the number of distorted cells is 1/4 or more of the total. Is indicated by "x".

As is clear from Table 1, the pneumatic tires of Examples 1 to 6 suppressed the flow during running while ensuring good sealing performance and uniformity, and achieved both of these performances in a well-balanced manner. On the other hand, in Comparative Examples 1 to 3, sufficient sealing properties could not be ensured because the ratio S1 / T1 and the ratio S2 / T2 were too small. Further, in Comparative Example 4 in which the ratios S1 / T1 and the ratio S2 / T2 were too large, sufficient uniformity could not be secured. Further, even in Comparative Examples 5 to 8 in which only one of the ratio S1 / T1 and the ratio S2 / T2 was excessive or too small, the sealing property and uniformity could not be satisfactorily secured.

1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt reinforcement layer 9 Inner liner layer 10 Sealant layer R1 Tread rubber layer R2 Side rubber layer R3 Rim cushion rubber layer CL Tire equatorial line

Claims (5)

A tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged inside the tire outer diameter direction of these sidewall portions. The tread has a carcass layer mounted between the pair of bead portions and a reinforcing layer including at least one belt layer arranged on the outer peripheral side of the carcass layer in the tread portion. In a pneumatic tire provided with a sealant layer made of an adhesive sealant material on the inner surface of the part.
The tread thickness T1 at the tire equatorial position and the sealant layer thickness S1 satisfy the relationship of 0.15 <S1 / T1 <0.35, and the tread portion at the end position of the belt layer A pneumatic tire characterized in that the thickness T2 and the thickness S2 of the sealant layer satisfy the relationship of 0.20 <S2 / T2 <0.40. Regarding the tread rubber arranged on the outer peripheral side of the reinforcing layer, when the thickness of the tread rubber at the tire equatorial position is T3 and the thickness of the tread rubber at the end position of the belt layer is T4, the tread rubber T3 and the thickness S1 of the sealant layer satisfy the relationship of 0.20 <S1 / T3 <0.40, and the thickness T4 of the tread rubber and the thickness S2 of the sealant layer are 0.25. The pneumatic tire according to claim 1, wherein the relationship of <S2 / T4 <0.45 is satisfied. The first or second claim, wherein the thickness T4 of the tread rubber and the loss tangent tan δ (60 ° C.) of the tread rubber at 60 ° C. satisfy the relationship of T4 × tan δ (60 ° C.) ≦ 5. Pneumatic tires. The width Ws of the sealant layer is equal to or greater than the width Wb of the belt layer, and the tire outer surface is measured at the end position of the belt layer when the normal internal pressure is applied and the sealant layer is placed vertically on a flat surface. Claim 1 is characterized in that the difference L1-L2 between the vertical distance L1 when no load is applied and the vertical distance L2 when a normal load is applied is within 15 mm with respect to the vertical distance from the plane. Pneumatic tire according to any one of ~ 3. The pneumatic tire according to any one of claims 1 to 4, wherein the adhesive sealant material is crosslinked.

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