JP7498391B2 - Pneumatic tires - Google Patents

Description

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

It has been proposed to provide a sealant layer on the radially inner side of the inner liner layer in the tread portion of a pneumatic tire (see, for example, Patent Document 1). In such a pneumatic tire, when a foreign object such as a nail penetrates the tread portion, the sealant material constituting the sealant layer flows into the through hole, suppressing the decrease in air pressure and making it possible to maintain driving.

In the above-mentioned self-sealing type pneumatic tire, if the viscosity of the sealant is low, the sealant can be expected to improve sealing performance in that it can easily flow into the through holes. However, if the sealant flows toward the tire center due to the heat and centrifugal force applied during driving, and as a result, if the through holes are outside the tire center region, there is a risk that the sealant will be insufficient and sufficient sealing performance will not be obtained. On the other hand, if the viscosity of the sealant is high, the flow of the sealant can be prevented, but the sealant will not easily flow into the through holes, and there is a risk that the sealing performance will be reduced. Therefore, when providing a sealant layer on the inner surface of the tire, it is necessary to achieve a good balance between suppressing the flow of the sealant during driving and ensuring good sealing performance.

JP 2006-152110 A

The object of the present invention is to provide a pneumatic tire with a sealant layer on the inner surface of the tire, which exhibits good sealing properties due to the sealant layer while preventing the sealant from flowing during driving.

The pneumatic tire of the present invention for achieving the above object includes a tread portion extending in a circumferential direction of the tire to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed radially inward of the sidewall portions, the pneumatic tire having a carcass layer mounted between the pair of bead portions, and a reinforcing layer including at least one belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and a sealant layer made of an adhesive sealant material is provided at least on an inner surface of the tread portion, the pneumatic tire being characterized in that a thickness T1 of the tread portion and a thickness S1 of the sealant layer at a tire equator position satisfy a relationship of 0.15<S1/T1<0.35, and a thickness T2 of the tread portion and a thickness S2 of the sealant layer at end positions of the belt layer satisfy a relationship of 0.20<S2/T2<0.40, and further comprising a thickness T3 of the tread portion and a thickness S4 of the sealant layer at end positions of the belt layer satisfy a relationship of 0.20<S2/T2<0.40 on the outer peripheral side of the reinforcing layer. Regarding the arranged tread rubber, when the thickness of the tread rubber at the tire equator position is T3 and the thickness of the tread rubber at an end position of the belt layer is T4, the thickness T3 of the tread rubber 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 satisfy the relationship of 0.25<S2/T4<0.45, the thicknesses T1, T2, T3, T4 have the relationships of T1>T2 and T3>T4, the width Ws of the sealant layer is equal to or greater than the width Wb of the belt layer, and with regard to the vertical distance between the outer surface of the tire and a plane measured at the end position of the belt layer when the tire is filled with normal internal pressure and placed vertically on a plane, a 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 .

The pneumatic tire of the present invention exhibits sealing properties by being provided with a sealant layer as described above, but in this case, the thickness of the sealant layer at each portion (the tire equator position and the end positions of the belt layer) is set within an appropriate range relative to the thickness of the tread portion, so it is possible to suppress the flow of the sealant during driving without impairing the sealing properties. In other words, the thickness of the tread portion affects the ease with which the tire deforms, and the more easily the tire deforms, the more likely the sealant will flow during driving, so by setting the ratio of the thickness of the tread portion to the thickness of the sealant layer within an appropriate range, it is possible to suppress flow during driving.

In the present invention, for the tread rubber disposed on the outer periphery of the reinforcing layer, when the thickness of the tread rubber at the tire equator is T3 and the thickness of the tread rubber at the end of the belt layer is T4, the thickness T3 of the tread rubber 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 satisfy the relationship of 0.25<S2/T4<0.45. This allows the ratio of the thickness of the tread portion (tread rubber) to the thickness of the sealant layer to be set in a more appropriate range, which is advantageous for suppressing flow during driving while maintaining sealing properties.

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 T4 × tan δ (60°C) ≦ 5. Setting it in this way makes it possible to suppress heat generation in the tread portion, which in turn suppresses heat generation in the sealant layer in contact with the tread portion, and is therefore advantageous in suppressing the flow of the sealant.

In the present invention, the width Ws of the sealant layer is equal to or larger than the width Wb of the belt layer, and the difference L1-L2 between the vertical distance L1 under no load and the vertical distance L2 under normal load measured at the end position of the belt layer when the tire is filled with normal internal pressure and placed vertically on a flat surface and between the outer surface of the tire and a flat surface is within 15 mm. This makes it possible to keep the deformation amount of the tire at the end position of the belt layer small, and to suppress the flow of the sealant caused by the deformation of the tire.

In the present invention, it is preferable that the adhesive sealant material is cross-linked. In this way, by forming the sealant layer from a pre-cross-linked adhesive sealant material, deformation of the sealant material in the tire width direction and tire circumferential direction can be prevented when the sealant layer (sealant material) is pressure-bonded to the inner surface of the tire.

In addition, in the present invention, when measuring the above-mentioned vertical distances L1 and L2, the tire is mounted on a regular rim and inflated to the above-mentioned internal pressure. The "regular rim" is a rim that is determined for each tire by the standard system including the standard on which the tire is based, for example, the standard rim for JATMA, the "Design Rim" for TRA, or the "Measuring Rim" for ETRTO. The "regular internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standard on which the tire is based, for example, the maximum air pressure for JATMA, the maximum value listed in the table "TIRE ROAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "INFLATION PRESSURE" for ETRTO, but is 180 kPa when the tire is for a passenger car. "Normal load" is the load determined for each tire by each standard, including the standard on which the tire is based. For JATMA, it is the maximum load capacity, for TRA, it is the maximum value listed in the table "TIRE ROAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and for ETRTO, it is the "LOAD CAPACITY". However, if the tire is for passenger cars, it is a load equivalent to 88% of the above load.

1 is a meridian cross-sectional view showing an example of a pneumatic tire of the present invention. FIG. 2 is an explanatory diagram showing an enlarged view of the vicinity of an end position of a belt layer of the pneumatic tire of the present invention.

The configuration of the present invention will be described in detail below with reference to the attached drawings.

As shown in FIG. 1, the pneumatic tire of the present invention (self-sealing type pneumatic tire) has a tread portion 1 that extends in the tire circumferential direction to form a ring, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged on the tire radial inner side of the sidewall portions 2. In FIG. 1, the symbol CL indicates the tire equator. Note that although not depicted in FIG. 1 because it is a meridian cross section, the tread portion 1, sidewall portions 2, and bead portions 3 each extend in the tire circumferential direction to form a ring, thereby forming the basic toroidal structure of the pneumatic tire. In addition, other tire components in the meridian cross section also extend in the tire circumferential direction to form a ring, unless otherwise specified.

In the example shown in FIG. 1, a carcass layer 4 is mounted between a pair of left and right bead portions 3. The carcass layer 4 includes multiple reinforcing cords extending in the tire radial direction, and is folded from the inside to the outside of the vehicle around the bead cores 5 and bead fillers 6 arranged in each bead portion 3. The bead fillers 6 are arranged on the outer periphery of the bead cores 5, and are enclosed by the main body and folded portions of the carcass layer.

A plurality of belt layers 7 (two layers in FIG. 1) are embedded on the outer periphery of the carcass layer 4 in the tread portion 1. Of these belt layers 7, the layer with the smallest belt width is called the smallest belt layer 7a, and the layer with the largest belt width is called the largest belt layer 7b. Each belt layer 7 includes a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set to, for example, a range of 10° to 40°. A belt reinforcing layer 8 is provided on the outer periphery of the belt layer 7 in the tread portion 1. In the illustrated example, two belt reinforcing layers 8 are provided: a full cover layer that covers the entire width of the belt layer 7, and an edge cover layer that is arranged further outward from the full cover layer and covers only the ends of the belt layer 7. The belt reinforcing layer 8 includes organic fiber cords oriented in the tire circumferential direction, and the angle of the organic fiber cords with respect to the tire circumferential direction is set to, for example, 0° to 5°.

In the tread portion 1, a tread rubber layer R1 is disposed 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) with different physical properties are laminated in the tire radial direction. A side rubber layer R2 is disposed 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 disposed on the outer peripheral side (outside in the tire width direction) of the carcass layer 4 in the bead portion 3.

An inner liner layer 9 is provided on the inner surface of the tire along the carcass layer 4. This inner liner layer 9 is a layer that prevents 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 made of butyl rubber that has air permeation prevention properties. Alternatively, it can be composed of a resin layer with a thermoplastic resin as a matrix. In the case of a resin layer, an elastomer component may be dispersed in a thermoplastic resin matrix.

The present invention relates to the sealant layer 10 and the thickness of the tread portion 1, which are provided on the inner surface of such a pneumatic tire. Therefore, as long as the pneumatic tire of the present invention has the sealant layer 10, which is described below, the basic structure of the tire is not limited to the above-mentioned structure, except for the characteristics related to the thickness of the tread portion 1, which is described below. The sealant layer 10 is attached to the inner surface of a pneumatic tire having the above-mentioned basic structure, and when a foreign object such as a nail penetrates the tread portion 1, the sealant material constituting the sealant layer 10 flows into the through hole and seals the through hole, thereby suppressing the decrease in air pressure and enabling the tire to continue running.

As shown in FIG. 1, a sealant layer 10 is provided on the radially inner side of the inner liner layer 9 in the tread portion 1. The sealant layer 10 is provided on the inner surface of the tire corresponding to the area where a foreign object such as a nail may be stuck during running, i.e., the ground contact area of the tread portion 1. Preferably, the width Ws of the sealant layer 10 is equal to or greater than the width Wb of the belt layer 7 (the width of the widest belt layer (maximum belt layer 7b in the illustrated example)). In addition, the protrusion amount w of the sealant layer 10 from the normal line of the carcass line passing through the widthwise end of the widest belt layer (maximum belt layer 7b in the illustrated example) is preferably within 20 mm.

As shown in FIG. 1, if the thickness of the tread portion 1 at the position of the tire equator CL is T1, the thickness of the sealant layer 10 at the position of the tire equator CL is S1, the thickness of the tread portion 1 at the end position of the belt layer 7 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. In this way, by setting the thickness of the sealant layer 10 at each part (the position of the tire equator CL and the end position of the belt layer 7) to a suitable range with respect to the thickness of the tread portion 1, it is possible to suppress the flow of the sealant during driving without impairing the sealing property. That is, the thickness of the tread portion 1 affects the ease of deformation of the tire, and the more easily the tire deforms, the more easily the sealant flows during driving, so by setting the ratio of the thickness of the tread portion 1 to the thickness of the sealant layer 10 to a suitable range, it is possible to suppress the flow during driving.

In this case, if the ratio S1/T1 is 0.15 or less, the sealant layer 10 is too thin, making it difficult to ensure sufficient sealing. If the ratio S1/T1 is 0.35 or more, the sealant layer 10 is too thick, raising concerns that the weight of the sealant layer 10 (amount of sealant material used) will increase, making it easier for flow to occur, and that uniformity will decrease. If the ratio S2/T2 is 0.20 or less, the sealant layer 10 is too thin, making it difficult to ensure sufficient sealing. If the ratio S2/T2 is 0.40 or more, the sealant layer 10 is too thick, raising concerns that the weight of the sealant layer 10 (amount of sealant material used) will increase, making it easier for flow to occur, and that uniformity will decrease.

Furthermore, as shown in FIG. 1, if the thickness of the tread rubber layer R1 at the tire equator CL is T3 and the thickness of the tread rubber layer R1 at the end of the belt layer 7 is T4, it is preferable that the thicknesses S1 and S2 of the sealant layer 10 described above satisfy the relationships of 0.20<S1/T3<0.40 and 0.25<S2/T4<0.45 with respect to the thicknesses T3 and T4. This allows the ratio of the thickness of the tread portion 1 (tread rubber layer R1) to the thickness of the sealant layer 10 to be set in a more appropriate range, which is advantageous for suppressing flow during driving while maintaining sealing properties.

In this case, if the ratio S1/T3 is 0.20 or less, the sealant layer 10 is too thin, making it difficult to ensure sufficient sealing. If the ratio S1/T3 is 0.40 or more, the sealant layer 10 is too thick, raising concerns that the weight of the sealant layer 10 (amount of sealant material used) will increase, making it easier for flow to occur, and that uniformity will decrease. If the ratio S2/T4 is 0.25 or less, the sealant layer 10 is too thin, making it difficult to ensure sufficient sealing. If the ratio S2/T4 is 0.45 or more, the sealant layer 10 is too thick, raising concerns that the weight of the sealant layer 10 (amount of sealant material used) will increase, making it easier for flow to occur, and that uniformity will decrease.

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

In the present invention, the thickness of the sealant layer 10 is not particularly limited as long as the ratio between the thickness of the sealant layer 10 and the tread portion 1 (tread rubber layer R1) is in the above-mentioned relationship, but in a typical pneumatic tire, the thickness of the sealant layer 10 can be set to, for example, 0.5 mm to 5.0 mm. By having a thickness of this order, it is possible to suppress the flow of the sealant during driving while ensuring good sealing properties. In addition, the processability when attaching the sealant layer 10 to the inner surface of the tire is also good. If the thickness of the sealant layer 10 is less than 0.5 mm, it is difficult to ensure 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 the average thickness.

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

The physical properties of the rubber constituting the tread rubber layer R1 (hereinafter referred to as tread rubber) are not particularly limited, but it is preferable that the product T4 x tan δ (60 ° C) 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 satisfy the relationship T4 x tan δ (60 ° C) ≦ 5. By setting in this way, heat generation in the tread portion 1 can be suppressed, and heat generation in the sealant layer 10 in contact with the tread portion 1 can also be suppressed, which is advantageous for suppressing the flow of the sealant. If this product T4 x tan δ (60 ° C) exceeds 5, the heat generation property of the tread portion 1 deteriorates and the above-mentioned effect cannot be expected. In addition, "tan δ" is a value measured using a viscoelasticity spectrometer in accordance with JIS K6394 under the conditions of a temperature of 60 ° C, an elongation deformation strain rate of 10% ± 2%, and a vibration frequency of 20 Hz.

In a tire with a sealant layer 10, the smaller the deformation of the tire during running, the less the effect on the sealant layer 10 and the more the sealant flow is suppressed. In particular, it is preferable that the deformation of the tire is small near the end of the sealant layer 10. As described above, in the present invention, the end of the sealant layer 10 is located beyond the end position of the belt layer 7, and the protrusion amount w is preferably 20 mm or less, so suppressing the deformation of the tire at the end position of the belt layer 7 is effective in suppressing the flow of the sealant. Therefore, as shown in FIG. 2, it is preferable to set the vertical distance between the outer surface of the tire and the plane measured at the end position of the belt layer 7 when the tire is filled with the normal internal pressure and placed vertically on a plane as follows. That is, when the vertical distance in the tire when no load is applied (solid line in the figure) is L1 and the vertical distance in the tire when a normal load is applied (dashed line in the figure) is L2, it is preferable that the difference between them L1-L2 is within 15 mm. By specifying the vertical distances L1 and L2 in this way, it is possible to keep the amount of tire deformation at the end positions of the belt layer 7 small, and to suppress the flow of the sealant caused by tire deformation. In this case, if the difference L1-L2 exceeds 15 mm, the deformation at the end positions of the belt layer 7 becomes large and the strain increases, which may make it easier for the sealant to flow.

The sealant layer 10 can be formed by later attaching it to the inner surface of a vulcanized pneumatic tire. For example, the sealant layer 10 can be formed by attaching a sealant material molded into a sheet shape around the entire circumference of the inner surface of the tire, or by attaching a sealant material molded into a string or strip shape in a spiral shape to the inner surface of the tire. In this case, it is preferable to use a sealant material that is cross-linked. By using a sealant material that has been cross-linked in advance in this way, it is possible to prevent deformation of the sealant material in the tire width direction and tire circumferential direction when the sealant layer 10 (sealant material) is pressure-attached to the inner surface of the tire.

The present invention will be further explained below 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 the basic structure shown in FIG. 1, and having a sealant layer on the inner surface of the tread portion, the ratio S1/T1 of the thickness S1 of the sealant layer to the thickness T1 of the tread portion at the tire equator, the ratio S2/T2 of the thickness S2 of the sealant layer to the thickness T2 of the tread portion at the end position of the belt layer, the ratio S1/T3 of the thickness S1 of the sealant layer to the thickness T3 of the tread rubber at the tire equator, the ratio S2/T4 of the thickness S2 of the sealant layer to the thickness T4 of the tread rubber at the end position of the belt layer, the product T4 x tan δ (60°C) of the tread rubber thickness T4 and the loss tangent tan δ (60°C) of the tread rubber at 60°C, and the difference L1-L2 between the vertical distance L1 at the end position of the belt layer when no load is applied and the vertical distance L2 when a normal load is applied, were set as shown in Table 1.

In all examples, thicknesses T1, T2, T3, T4, S1, and S2 were measured along the normal to the carcass line (the contour line of the outer peripheral surface of the carcass layer in the meridian cross section). The loss tangent tanδ (60°C) of the tread rubber at 60°C was measured using a viscoelasticity spectrometer in accordance with JIS K6394 under the following conditions: temperature 60°C, elongation deformation rate 10%±2%, and vibration frequency 20Hz. Vertical distances L1 and L2 are the vertical distances between the outer surface of the tire and a plane measured under each load condition at the end position of the belt layer when the tire is filled with normal internal pressure and placed vertically on a flat surface.

These test tires were evaluated for sealing, uniformity, and fluidity during driving using the following test methods, and the results are shown in Table 1.

Sealing property Each test tire was mounted on a wheel with a rim size of 18 x 8.5J and mounted on a test vehicle, and a nail with a diameter of 4.0 mm was driven into the tread portion under the conditions of an initial air pressure of 250 kPa, a load of 8.5 kN, and a temperature of 23°C (room temperature), and the air pressure was measured after the nail was removed and the tire was left to stand for 1 hour. The evaluation results were shown in the following four stages. The evaluation result of "○" or "◎" means that sufficient sealing property was exhibited, and "◎" means that particularly excellent sealing property was exhibited.
◎: Air pressure after standing is 240 kPa or more and 250 kPa or less. ○: Air pressure after standing is 230 kPa or more and less than 240 kPa. △: 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 mounted on a wheel with a rim size of 18 x 8.5J, and the radial force variation (RFV) was measured using a uniformity measurement test device at an air pressure of 200 kPa. However, the measurement conditions were in accordance with the JASO standard. The results obtained were shown in the "Uniformity" column of Table 1 as an index with the value of Comparative Example 1 being 100. An index value of "90" or more means that good uniformity was maintained.

The test tire was mounted on a wheel with a rim size of 18×8.5J and mounted on a drum test machine, and the tire was driven for 1 hour under the conditions of an air pressure of 220 kPa, a load of 8.5 kN, and a running speed of 80 km/h, and the flow state of the sealant after the run was examined. The evaluation results were obtained by drawing 20×40 squares of 5 mm grid lines on the surface of the sealant layer before the run, and counting the number of squares whose shape was distorted after the run. The results were shown as "○" when no sealant flow was observed (the number of distorted squares was 0), "△" when the number of distorted squares was less than 1/4 of the total, and "×" when the number of distorted squares was 1/4 or more of the total.

As is clear from Table 1, the pneumatic tires of Examples 1 to 6 suppressed flow during driving while ensuring good sealing and uniformity, achieving a good balance between these performance properties. On the other hand, Comparative Examples 1 to 3 could not ensure sufficient sealing because the ratios S1/T1 and S2/T2 were too small. Comparative Example 4, in which the ratios S1/T1 and S2/T2 were too large, could not ensure sufficient uniformity. Furthermore, Comparative Examples 5 to 8, in which only one of the ratios S1/T1 or S2/T2 was too large or too small, also failed to ensure good sealing and uniformity.

Reference Signs List 1 Tread portion 2 Sidewall portion 3 Bead portion 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt reinforcing layer 9 Inner liner layer 10 Sealant layer R1 Tread rubber layer R2 Side rubber layer R3 Rim cushion rubber layer CL Tire equator

Claims (2)

A pneumatic tire comprising a tread portion extending in a circumferential direction of the tire and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side of the sidewall portions in the outer radial direction of the tire, a carcass layer mounted between the pair of bead portions, and a reinforcing layer including at least one belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and a sealant layer made of an adhesive sealant material is provided on at least the inner surface of the tread portion,
a thickness T1 of the tread portion and a thickness S1 of the sealant layer at a tire equator satisfy a relationship of 0.15<S1/T1<0.35, and a thickness T2 of the tread portion and a thickness S2 of the sealant layer at an end position of the belt layer satisfy a relationship of 0.20<S2/T2<0.40,
Furthermore, with respect to a tread rubber disposed on the outer circumferential side of the reinforcing layer, when a thickness of the tread rubber at the tire equator position is T3 and a thickness of the tread rubber at an end position of the belt layer is T4, the thickness T3 of the tread rubber and the thickness S1 of the sealant layer satisfy a relationship of 0.20<S1/T3<0.40, and the thickness T4 of the tread rubber and the thickness S2 of the sealant layer satisfy a relationship of 0.25<S2/T4<0.45,
The thicknesses T1, T2, T3, and T4 have a relationship of T1>T2 and T3>T4,
A pneumatic tire characterized in that a width Ws of the sealant layer is equal to or greater than a width Wb of the belt layer, and with respect to a vertical distance between an outer surface of the tire and a plane measured at an end position of the belt layer when the tire is filled with a normal internal pressure and placed vertically on the plane, a difference L1-L2 between the vertical distance L1 at no load and the vertical distance L2 at a normal load is within 15 mm . 2. The pneumatic tire of claim 1 , wherein the adhesive sealant material is crosslinked.

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