JP2022067277A - Inflated tire - Google Patents

Abstract

To provide an inflated tire capable of suppressing a separation at the end portion of a belt ply.SOLUTION: An inflated tire includes: a carcass; and first, second and third belt plies laminated in sequence on the outer circumference of the carcass at a tread from the internal side relative to a tire diameter direction to the external side relative to such a direction. The end portion of the third belt ply is located inwardly relative to the end portion of the second belt ply in the tire widthwise direction, and is located so as to be apart from the outer circumferential surface of the second belt ply in the tire diameter direction. Further provided are an inter-belt rubber placed between the end portion of the third belt ply and the outer circumferential surface of the second belt ply, and an under-belt rubber placed between the end portions of the first and second belt plies and the outer circumferential surface of the carcass. The inter-belt rubber has a higher rubber rigidity than that of the under-belt rubber, and the under-belt rubber has a smaller loss tangent tanδ than that of the inter-belt rubber.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to pneumatic tires.

As a pneumatic tire used for a truck or a bus, a tire in which three or more belt plies are provided on the outer circumference of a carcass in a tread is known. For example, Patent Document 1 discloses a pneumatic tire provided with four belt plies.

By the way, at the end of the belt ply, distortion is concentrated and separation is likely to occur.

Japanese Unexamined Patent Publication No. 2019-99077

An object of the present disclosure is to provide a pneumatic tire capable of suppressing separation at the end of a belt ply.

The pneumatic tires of the present disclosure include a carcass and first, second, and third belt plies that are sequentially laminated from the inner side to the outer side in the tire radial direction on the outer periphery of the carcass in the tread.
The end of the third belt ply is located inside the end of the second belt ply in the tire width direction and is located away from the outer peripheral surface of the second belt ply in the tire radial direction. Ori,
Inter-belt rubber arranged between the end of the third belt ply and the outer peripheral surface of the second belt ply, and the end of the first and second belt plies and the outer peripheral surface of the carcass. With rubber under the belt placed between,
The interbelt rubber has a higher rubber hardness than the underbelt rubber, and the underbelt rubber has a smaller loss tangent tan δ than the interbelt rubber.

A half cross-sectional view showing one side of a cut surface of a pneumatic tire according to an embodiment on the tire meridional surface. Enlarged view of the II region of the pneumatic tire shown in FIG. Enlarged view of the III region of the pneumatic tire shown in FIG.

Hereinafter, an embodiment of a pneumatic tire will be described with reference to FIGS. 1 to 3. In each drawing, the dimensional ratio of the drawings and the actual dimensional ratio do not always match, and the dimensional ratios between the drawings do not necessarily match.

In each figure, the first direction D1 is the tire width direction D1 parallel to the tire rotation axis which is the rotation center of the pneumatic tire (hereinafter, also simply referred to as “tire”) 1, and the second direction D2 is. , The tire radial direction D2, which is the tire radial direction. The tire circumferential direction (not shown) is the direction around the tire rotation axis.

In the tire width direction D1, the inside is the side closer to the tire equatorial plane S1 and the outside is the side far from the tire equatorial plane S1. Further, in the tire radial direction D2, the inner side is on the side closer to the tire rotation axis, and the outer side is on the side far from the tire rotation axis.

The tire equatorial plane S1 is a plane orthogonal to the tire rotation axis and located at the center of the tire width direction D1 of the tire 1, and the tire meridional plane is a plane including the tire rotation axis and the tire equatorial line. It is a plane orthogonal to the plane S1. The tire equatorial line is a line where the outer surface of the tire 1 in the tire radial direction D2 (described later, the tread surface 3a) and the tire equatorial surface S1 intersect.

As shown in FIG. 1, the tire 1 according to the present embodiment has a pair of beads (not shown) having a bead core (not shown) and a sidewall 2 extending outward from each bead in the tire radial direction D2. The tread 3 is connected to the outer end of the pair of sidewalls 2 in the tire radial direction D2, and the outer surface of the tire radial direction D2 is in contact with the road surface. In the present embodiment, the tire 1 is a pneumatic tire 1 in which air is introduced and is mounted on the rim.

Further, the tire 1 includes a carcass 4 that is bridged between a pair of bead cores and an inner liner 5 that is arranged inside the carcass 4 and has an excellent function of blocking gas permeation in order to maintain air pressure. There is. The carcass 4 and the inner liner 5 are arranged along the inner circumference of the tire over the bead, the sidewall 2, and the tread 3.

The tread 3 includes a tread rubber 30 having a tread surface 3a that is in contact with the road surface, and a belt 6 that is arranged between the tread rubber 30 and the carcass 4. The tread surface 3a has a ground contact surface that actually touches the road surface, and the outer end of the ground contact surface in the tire width direction D1 is referred to as a ground contact end 3b. In addition, as the ground contact surface, the tire 1 is rim-assembled on the regular rim, the tire 1 is placed vertically on a flat road surface with the regular internal pressure charged, and the tread surface 3a that touches the road surface when a regular load is applied is provided. Point to.

A regular rim is a rim defined for each tire 1 in a standard system including a standard on which the tire 1 is based. For example, a standard rim for JATTA and "Measuring Rim" for TRA and ETRTO. ..

The regular internal pressure is the air pressure defined for each tire 1 in the standard system including the standard on which the tire 1 is based. The maximum value described in "INFLATION PRESSURES" is "INFRATION PRESSURE" in the case of ETRTO, but 180 kPa when the tire 1 is for a passenger car, but the tire described as Extra Load or Reinforced. In the case, it is set to 220 kPa.

The normal load is the load defined for each tire 1 in the standard system including the standard on which the tire 1 is based. If it is JATTA, the maximum load capacity, and if it is TRA, the maximum described in the above table. If the value is ETRTO, it is "LOAD CAPACITY", but if the tire 1 is for a passenger car, it is 85% of the corresponding load of an internal pressure of 180 kPa.

The tread rubber 30 has a cap rubber 30a having a tread surface 3a and a base rubber 30b provided inside the tire radial direction D2 of the cap rubber 30a. The cap rubber 30a includes a plurality of main grooves 31a extending in the tire circumferential direction. The main groove 31a extends continuously in the tire circumferential direction. The main groove 31a may be provided with a portion having a shallow groove, that is, a so-called tread wear indicator (not shown) so that the degree of wear can be known by being exposed as the main groove 31a is worn. Further, for example, the main groove 31a may have a groove width of 5 mm or more. The number of main grooves 31a is not particularly limited, but is two in the present embodiment.

The tread rubber 30 includes a plurality of land 3c and 3d partitioned by a plurality of main grooves 31a and a pair of ground contact ends 3b. The number of land 3c and 3d is not particularly limited, but in the present embodiment, the number is three.

The land 3c partitioned by the main groove 31a and the ground contact end 3b is referred to as a shoulder land 3c, and the land 3d partitioned by a pair of adjacent main grooves 31a is referred to as a center land 3d. The shoulder land 3c includes an auxiliary groove 31b extending in the tire circumferential direction. Further, the center land 3d includes a pair of auxiliary grooves 31c extending in the tire circumferential direction. The groove width of the sub-grooves 31b and 31c is narrower than the groove width of the main groove 31a, and is, for example, 5 mm or less.

A belt 6 for reinforcing the carcass 4 is provided on the outer periphery of the carcass 4 in the tread 3. The belt 6 includes four belt plies 61 to 64 that are laminated in order from the inside to the outside of the tire radial direction D2. All of the four belt plies 61 to 64 are continuously arranged on both sides in the tire width direction D1 with the tire equatorial plane S1 interposed therebetween.

The four belt plies 61 to 64 each include a plurality of cords arranged in parallel in a bamboo blind shape, and are formed by coating them with rubber. The cord is preferably a steel cord.

Of the four belt plies 61 to 64, the cord of the first belt ply 61, which is the first from the carcass 4 toward the outer circumference, extends at an angle of 35 to 75 ° with respect to the tire circumferential direction. There is. In the present embodiment, the cord of the first belt ply 61 is inclined at an angle of 55 ° with respect to the tire circumferential direction.

Of the four belt plies 61 to 64, the cords of the second belt ply 62 and the third belt ply 63, which are the second from the carcass 4 toward the outer circumference, are the cords of the third belt ply 63 with respect to the tire circumferential direction. They are inclined in opposite directions and intersect. Further, the cords of the second belt ply 62 and the third belt ply 63 are inclined at the same angle with respect to the tire circumferential direction. The second belt ply 62 and the third belt ply 63 are also collectively referred to as a working belt. The cords of the second belt ply 62 and the third belt ply 63 extend at an angle of 10 to 30 ° with respect to the tire circumferential direction. In the present embodiment, the cords of the second belt ply 62 and the third belt ply 63 are inclined at an angle of 20 ° with respect to the tire circumferential direction. Further, the cord of the second belt ply 62 is inclined in the same direction as the cord of the first belt ply 61 with respect to the tire circumferential direction.

Further, of the four belt plies 61 to 64, the cord of the fourth belt ply 64, which is the fourth from the carcass 4 toward the outer circumference, is inclined at an angle of 10 to 30 ° with respect to the tire circumferential direction. It is extended. In the present embodiment, the cord of the fourth belt ply 64 is inclined at an angle of 20 ° with respect to the tire circumferential direction. Further, the cord of the fourth belt ply 64 is inclined in the same direction as the cord of the third belt ply 63 with respect to the tire circumferential direction.

The end portion 62a of the second belt ply 62 is located outside the end portion 61a of the first belt ply 61 in the tire width direction D1. Further, the end portion 63a of the third belt ply 63 is located outside the tire width direction D1 from the end portion 61a of the first belt ply 61, and is inside the tire width direction D1 from the end portion 62a of the second belt ply 62. Located in. Further, the end portion 64a of the fourth belt ply 64 is located inside the tire width direction D1 with respect to the end portion 61a of the first belt ply 61. Therefore, in the first to fourth belt plies 61 to 64, the width of the tire width direction D1 becomes wider in the order of the fourth belt ply 64, the first belt ply 61, the third belt ply 63, and the second belt ply 62. ..

The end portion 61a of the first belt ply 61, the end portion 62a of the second belt ply 62, and the end portion 63a of the third belt ply 63 are located outside the auxiliary groove 31b in the tire width direction D1. Further, the end portion 64a of the fourth belt ply 64 is located outside the main groove 31a in the tire width direction D1 and inside the sub groove 31b in the tire width direction D1.

The outer peripheral surface of the first belt ply 61 is in close contact with the second belt ply 62 without a gap. On the other hand, on the inner peripheral surface of the first belt ply 61, the inner portion in the tire width direction D1 is in contact with the carcass 4 without a gap, and the outer portion in the tire width direction D1 is arranged so as to be separated from the carcass 4. The outer peripheral surface of the first belt ply 61 in the tire width direction D1 is covered with the edge tape 65. The edge tape 65 is for improving the adhesiveness between the members.

An inter-belt rubber 71 is arranged between the end portion 63a of the third belt ply 63 and the outer peripheral surface of the second belt ply 62. The portion of the rubber between the belts 71 inside the tire width direction D1 is sandwiched between the inner peripheral surface of the third belt ply 63 and the outer peripheral surface of the second belt ply 62. On the other hand, the portion of the rubber between the belts 71 on the outer side of the tire width direction D1 is in contact with the base rubber 30b and is sandwiched between the inner peripheral surface of the base rubber 30b and the outer peripheral surface of the second belt ply 62. Further, the portion of the inter-belt rubber 71 outside the tire width direction D1 extends along the outer peripheral surface of the second belt ply 62 and reaches the end portion 62a. The end portion 62a of the second belt ply 62 and the end portion 63a of the third belt ply 63 are each wrapped with the edge tape 65.

A rubber under the belt 72 is arranged between the end portion 61a of the first belt ply 61 and the end portion 62a of the second belt ply 62 and the outer peripheral surface of the carcass 4. The inner portion of the rubber under the belt 72 in the tire width direction D1 is sandwiched between the inner peripheral surface of the first belt ply 61, the inner peripheral surface of the second belt ply 62, and the outer peripheral surface of the carcass 4. On the other hand, the portion of the rubber under the belt 72 outside the tire width direction D1 is in contact with the base rubber 30b and is sandwiched between the inner peripheral surface of the base rubber 30b and the outer peripheral surface of the carcass 4. Further, the portion of the rubber under the belt 72 outside the tire width direction D1 extends beyond the end portion 62a of the second belt ply 62 to the sidewall 2 and has a sidewall rubber 21 arranged on the outer surface of the sidewall 2. I'm in contact.

By the way, the third belt ply 63 is a belt ply outside the tire radial direction D2 in the working belt, and strain is particularly concentrated at the end 63a of the third belt ply 63, and separation is likely to occur. According to the configuration according to the present embodiment, since the end portion 63a of the third belt ply 63 is separated from the end portion 62a of the second belt ply 62, the distortion applied to the end portion 63a of the third belt ply 63 is reduced. , Separation at the end 63a of the third belt ply 63 is suppressed.

The rubber between the belts 71 has a higher rubber hardness than the rubber under the belt 72. By increasing the rubber hardness of the inter-belt rubber 71, the movement of the end portion 63a of the third belt ply 63 is suppressed, so that the separation at the end portion 63a of the third belt ply 63 is effectively suppressed. The rubber hardness of the present invention is the rubber hardness measured at 25 ° C. by the durometer hardness test (type A) of JIS K6253. In the present embodiment, for example, the rubber hardness of the interbelt rubber 71 is 65 to 75 °, and the rubber hardness of the rubber under the belt 72 is 50 to 60 °.

The rubber hardness of the inter-belt rubber 71 is higher than the rubber hardness of the base rubber 30b. According to this configuration, by arranging the rubber having high hardness on the rubber between the belts 71, it is possible to suppress the movement of the end portion 63a of the third belt ply 63 and prevent the separation. For example, the rubber hardness of the base rubber 30b is 60 to 65 °.

Further, the rubber hardness of the rubber under the belt 72 is lower than the rubber hardness of the base rubber 30b. According to this configuration, by arranging the high hardness rubber on the base rubber 30b which is a member close to the tread surface 3a, the movement of the end portion 62a of the second belt ply 62 and the end portion 63a of the third belt ply 63 can be performed. It can be suppressed and separation can be prevented.

Further, the rubber hardness of the rubber under the belt 72 is lower than the rubber hardness of the sidewall rubber 21. According to this configuration, by arranging the rubber having a low hardness on the rubber under the belt 72, it is possible to absorb the strain applied to the end portion 62a of the second belt ply 62 and prevent the separation. For example, the rubber hardness of the sidewall rubber 21 is 60 to 65 °.

The rubber under the belt 72 has a smaller loss tangent tan δ than the rubber between the belts 71. That is, the rubber under the belt 72 has lower heat generation than the rubber between the belts 71. By reducing the loss tangent tan δ of the rubber under the belt 72 (having low heat generation), heat generation at the end 62a of the second belt ply 62 can be suppressed, and heat generation at the end 62a of the second belt ply 62 can be suppressed. Separation is suppressed. The loss tangent tan δ of the present invention is obtained by measuring the loss coefficient tan δ under the conditions of a frequency of 50 Hz, a static distortion of 10%, a dynamic strain of 2%, and a temperature of 0 ° C. using a leospectometer E4000 manufactured by USM. In the present embodiment, for example, when the loss tangent tan δ of the base rubber 30b is “100”, the loss tangent tan δ of the rubber under the belt 72 is “60” and the loss tangent tan δ of the interbelt rubber 71 is “130”. be.

The loss tangent tan δ of the base rubber 30b is smaller than the loss tangent tan δ of the interbelt rubber 71. According to this configuration, by arranging the low heat generation rubber on the base rubber 30b, it is possible to prevent the generation of separation due to heat generation at the end portion 62a of the second belt ply 62 and the end portion 63a of the third belt ply 63. Can be done. For example, when the loss tangent tan δ of the base rubber 30b is “100”, the loss tangent tan δ of the interbelt rubber 71 is “130”.

Further, the loss tangent tan δ of the rubber under the belt 72 is smaller than the loss tangent tan δ of the base rubber 30b. According to this configuration, by arranging the rubber having low heat generation on the rubber under the belt 72, it is possible to prevent the generation of separation due to heat generation at the end portion 62a of the second belt ply 62. For example, when the loss tangent tan δ of the base rubber 30b is “100”, the rubber under the belt 72 is “60”.

Further, the loss tangent tan δ of the rubber under the belt 72 is smaller than the loss tangent tan δ of the sidewall rubber 21. According to this configuration, by arranging the rubber having low heat generation on the rubber under the belt 72, it is possible to prevent the generation of separation due to heat generation at the end portion 62a of the second belt ply 62. For example, when the loss tangent tan δ of the base rubber 30b is “100”, the loss tangent tan δ of the sidewall rubber 21 is “170”.

Like the edge tape 65, the inter-belt rubber 71 is made of rubber having excellent adhesiveness. As a result, in the unvulcanized tire before vulcanization molding, the adhesiveness between the second belt ply 62 and the third belt ply 63 can be enhanced, and air entry during unvulcanization tire molding can be suppressed.

As shown in FIG. 2, the distance D between the cord 631 at the end 63a of the third belt ply 63 and the cord 621 of the second belt ply 62 closest to the cord 631 is 1.8 to 3.8 mm. Is preferable. By setting the distance D to 1.8 to 3.8 mm, durability can be improved while maintaining uneven wear resistance. If the distance D is smaller than 1.8 mm, the ground contact length of the shoulder portion becomes short, so that (ground contact length B of the shoulder portion) / (ground contact length A of the center portion) becomes small, and the durability is improved, but the durability is improved. Uneven wear resistance may worsen. On the other hand, when the distance D is larger than 3.8 mm, the ground contact length of the shoulder portion becomes long, so that (the ground contact length B of the shoulder portion) / (the ground contact length A of the center portion) becomes large, and the uneven wear resistance is improved. However, the durability may deteriorate. The ground contact length B of the shoulder portion is specifically the ground contact length at the ground contact end 3b, and the ground contact length A of the center portion is specifically the ground contact length at the tire equatorial plane S1.

The distance W in the tire width direction D1 from the end portion 63a of the third belt ply 63 to the end portion 62a of the second belt ply 62 is preferably 4 to 17 mm. When the distance W is smaller than 4 mm, air pools occur between the belt 6 and the tread rubber 30, specifically near the end 62a of the second belt ply 62 and the end 63a of the third belt ply 63, resulting in durability. The sex may worsen. On the other hand, if the distance W is larger than 17 mm, strain may be concentrated on the end portion 62a of the second belt ply 62, and the durability may be deteriorated.

Further, the distance W is preferably smaller than the distance X in the tire width direction D1 from the end portion 62a of the second belt ply 62 to the outer surface 2a of the sidewall 2. According to this configuration, the end portion 62a of the second belt ply 62 is not too far from the end portion 63a of the third belt ply 63, and the end portion 62a of the second belt ply 62 is from the outer surface 2a of the sidewall 2. Since it is separated to some extent, the strain is prevented from being concentrated on the end portion 62a of the second belt ply 62, and the separation at the end portion 62a of the second belt ply 62 is suppressed.

As shown in FIG. 3, the distance Y in the tire radial direction D2 from the end portion 63a of the third belt ply 63 to the tread surface 3a is from the end portion 63a of the third belt ply 63 to the outer surface 2a of the sidewall 2. It is smaller than the distance Z in the tire width direction D1. According to this configuration, since the end portion 63a of the third belt ply 63 is separated from the outer surface 2a of the sidewall 2 to some extent, it is possible to prevent strain from concentrating on the end portion 63a of the third belt ply 63, and to prevent the strain from concentrating on the end portion 63a of the third belt ply 63. Separation at the end 63a of the ply 63 is suppressed.

The cross-sectional shape and the positions of the members (distance W, distance X, distance Y, distance Z, etc.) are, for example, in a cut sample prepared by cutting the tire 1 at two points with a length of about 100 mm in the tire circumferential direction. , The bead spacing is measured while holding it by attaching a rubber tape or the like so that the regular rim is attached.

As described above, the pneumatic tire 1 according to the present embodiment is laminated on the outer periphery of the carcass 4 and the carcass 4 in the tread 3 in order from the inside to the outside of the tire radial direction D2, the first, the second, and the first. The third belt ply 63 is provided with the third belt ply 61, 62, 63, and the end portion 63a of the third belt ply 63 is located inside the end portion 62a of the second belt ply 62 in the tire width direction D1 and has a tire diameter. Between the belts located apart from the outer peripheral surface of the second belt ply 62 in the direction D2 and arranged between the end 63a of the third belt ply 63 and the outer peripheral surface of the second belt ply 62. The rubber 71 is provided with an underbelt rubber 72 arranged between the ends 61a and 62 of the first and second belt plies 61 and 62 and the outer peripheral surface of the carcass 4, and the interbelt rubber 71 is a belt. The rubber hardness is higher than that of the lower rubber 72, and the loss tangent tan δ of the under-belt rubber 72 is smaller than that of the inter-belt rubber 71.

According to this configuration, since the end portion 63a of the third belt ply 63 is separated from the end portion 62a of the second belt ply 62, the distortion applied to the end portion 63a of the third belt ply 63 is reduced. Separation at the end 63a of the third belt ply 63 is suppressed. Further, by increasing the rubber hardness of the inter-belt rubber 71, the movement of the end portion 63a of the third belt ply 63 is suppressed, so that the separation at the end portion 63a of the third belt ply 63 is effective. It is suppressed. Further, by reducing the loss tangent tan δ of the rubber under the belt 72, heat generation at the end portion 62a of the second belt ply 62 can be suppressed, and separation at the end portion 62a of the second belt ply 62 can be suppressed. Will be done.

Further, in the pneumatic tire 1 according to the present embodiment, the distance W in the tire width direction D1 from the end portion 63a of the third belt ply 63 to the end portion 62a of the second belt ply 62 is the second belt. The configuration is such that it is smaller than the distance X in the tire width direction D1 from the end portion 62a of the ply 62 to the outer surface of the tire.

According to this configuration, the strain is prevented from being concentrated on the end portion 62a of the second belt ply 62, and the separation at the end portion 62a of the second belt ply 62 is suppressed.

Further, in the pneumatic tire 1 according to the present embodiment, the distance Y in the tire radial direction D2 from the end portion 63a of the third belt ply 63 to the outer surface 3a of the tread 3 is the end of the third belt ply 63. It is smaller than the distance Z in the tire width direction D1 from the portion 63a to the outer surface 2a of the sidewall 2. According to this configuration, since the end portion 63a of the third belt ply 63 is separated from the outer surface 2a of the sidewall 2 to some extent, it is possible to prevent strain from concentrating on the end portion 63a of the third belt ply 63. Separation at the end 63a of the belt ply 63 of 3 is suppressed.

The pneumatic tire 1 is not limited to the configuration of the above-described embodiment, and is not limited to the above-mentioned action and effect. Further, it goes without saying that the pneumatic tire 1 can be modified in various ways within a range that does not deviate from the gist of the present invention. For example, each configuration and each method of the above-mentioned plurality of embodiments may be arbitrarily adopted and combined, and further, one or a plurality of configurations and methods according to the following various modified examples may be arbitrarily selected. Of course, it may be adopted in the configuration and method according to the above-described embodiment.

In the pneumatic tire 1 according to the above embodiment, in the pneumatic tire 1 according to the present embodiment, the tire width direction from the end 63a of the third belt ply 63 to the end 62a of the second belt ply 62. The distance W of D1 is smaller than the distance X of the tire width direction D1 from the end portion 62a of the second belt ply 62 to the outer surface of the tire. However, the pneumatic tire 1 is not limited to such a configuration. For example, the distance W can be made larger than the distance X by appropriately adjusting the physical property value and the thickness of the tread rubber 30.

1 ... pneumatic tire, 2 ... sidewall, 2a ... outer surface of sidewall, 3 ... tread, 3a ... tread surface, 3b ... grounding edge, 3c, 3d ... land, 4 ... carcass, 5 ... inner liner, 6 ... Belt, 21 ... Sidewall rubber, 30 ... Tread rubber, 30a ... Cap rubber, 30b ... Base rubber, 31a ... Main groove, 31b, 31c ... Sub-groove, 61 ... First belt ply, 61a ... End of first belt ply Part, 62 ... 2nd belt ply, 62a ... end of 2nd belt ply, 63 ... 3rd belt ply, 63a ... end of 3rd belt ply, 64 ... 4th belt ply, 64a ... 4th belt ply End, 71 ... rubber between belts, 72 ... rubber under the belt, 621 ... cord, 631 ... cord, D1 ... tire width direction, D2 ... tire radial direction, S1 ... tire equatorial plane

Claims (3)

A carcass and a first, second, and third belt ply that are sequentially laminated from the inner side to the outer side in the tire radial direction on the outer periphery of the carcass in the tread are provided.
The end of the third belt ply is located inside the end of the second belt ply in the tire width direction and is located away from the outer peripheral surface of the second belt ply in the tire radial direction. And
Inter-belt rubber arranged between the end of the third belt ply and the outer peripheral surface of the second belt ply, and the end of the first and second belt plies and the outer peripheral surface of the carcass. With rubber under the belt placed between,
The interbelt rubber has a higher rubber hardness than the underbelt rubber, and the underbelt rubber has a smaller loss tangent tan δ than the interbelt rubber, and is a pneumatic tire. The distance in the tire width direction from the end of the third belt ply to the end of the second belt ply is larger than the distance in the tire width direction from the end of the second belt ply to the outer surface of the tire. The small, pneumatic tire according to claim 1. The tire radial distance from the end of the third belt ply to the outer surface of the tread is smaller than the tire width distance from the end of the third belt ply to the outer surface of the sidewall. The pneumatic tire according to claim 1 or 2.

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