JP2021167170A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire improved in durability against high inner pressure, while achieving high load bearing capability and space-saving.SOLUTION: An outside diameter OD of a pneumatic tire 10 is 350 mm or more and 600 mm or less, and a width SW of the tire is 125 mm or more and 255 mm or less. Oblateness of the pneumatic tire 10 is 40% or more and 75% or less, and a rim diameter RD of a rim wheel is 10 inches or more and 22 inches or less, and a rim width RW of the rim wheel is 3.8 inches or more and 8 inches or less, which satisfy relational expressions of 0.78≤RW/SW≤0.99 and 0.56≤RD/OD≤0.75. A first cord of a first belt 51 is provided along a tire circumferential direction, and a second cord of a second belt 52 is provided to incline with respect to the tire circumferential direction. A diameter of the first cord is same as a diameter of the second cord or larger than the diameter of the second cord.SELECTED DRAWING: Figure 3

Description

The present invention relates to a small diameter pneumatic tire having an enhanced load bearing capacity.

Conventionally, pneumatic tires having a smaller diameter while increasing the load-bearing capacity (maximum load capacity) have been known (see Patent Document 1). It is said that such pneumatic tires can save space for small vehicles and secure a large riding space.

JP-A-2018-138435

In recent years, a new small shuttle bus has been proposed that focuses on the transportation of people and goods in the city. Such a small shuttle bus has a total length of about 5 m and a total width of about 2 m, and it is assumed that the gross vehicle weight may exceed 3 tons. Space saving is also required for pneumatic tires mounted on such small shuttle buses.

Further, it is assumed that a high internal pressure is set for the pneumatic tire mounted on such a small shuttle bus, and sufficient durability against a high internal pressure is required.

In particular, such a pneumatic tire has a problem that the shoulder portion of the tread near the end of the belt layer tends to grow in the tire radial direction due to the high internal pressure.

Therefore, the following disclosure is made in view of such a situation, and aims to provide a pneumatic tire having improved durability against a high internal pressure while achieving high load-bearing capacity and space saving. ..

One aspect of the present disclosure is a pneumatic tire (pneumatic tire 10) provided with a belt layer (for example, a belt layer 50) inside the tread (tread 20) in contact with the road surface in the tire radial direction. The outer diameter OD is 350 mm or more and 600 mm or less, the tire width SW of the pneumatic tire is 125 mm or more and 255 mm or less, and the flatness ratio of the pneumatic tire is 40% or more and 75% or less. The rim diameter RD of the rim wheel (rim wheel 100) assembled to the pneumatic tire is 10 inches or more and 22 inches or less, and the rim width RW of the rim wheel is 3.8 inches or more and 8 inches or less. , 0.78 ≦ RW / SW ≦ 0.99, and 0.56 ≦ RD / OD ≦ 0.75, and the belt layer is a first belt having a plurality of first cords (first belt 51). ) And a second belt (second belt 52) having a plurality of second cords (second code 52a, second code 52b), and the first cord is provided along the tire circumferential direction. The second cord is provided so as to be inclined with respect to the tire circumferential direction, and the diameter of the first cord is the same as the diameter of the second cord or larger than the diameter of the second cord.

According to the above-mentioned pneumatic tire, durability against high internal pressure can be enhanced while achieving high load bearing capacity and space saving.

FIG. 1 is an overall schematic side view of the vehicle 1 on which the pneumatic tire 10 is mounted. FIG. 2 is a cross-sectional view of the pneumatic tire 10 and the rim wheel 100. FIG. 3 is a cross-sectional view of the pneumatic tire 10. FIG. 4 is a partially enlarged cross-sectional view of the belt layer 50. FIG. 5 is a partially exploded plan view of the carcass 40 and the belt layer 50. FIG. 6 is a partially enlarged cross-sectional view of the belt layer 50A according to the first modification. FIG. 7 is a partially enlarged cross-sectional view of the belt layer 50B according to the second modification.

Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

(1) Schematic configuration of a vehicle on which a pneumatic tire is mounted FIG. 1 is an overall schematic side view of a vehicle 1 on which the pneumatic tire 10 according to the present embodiment is mounted. As shown in FIG. 1, in the present embodiment, the vehicle 1 is a four-wheeled vehicle. The vehicle 1 is not limited to four wheels, and may have a six-wheel configuration or an eight-wheel configuration.

The vehicle 1 is equipped with a predetermined number of pneumatic tires 10 according to the wheel configuration. Specifically, the pneumatic tire 10 assembled to the rim wheel 100 is mounted on the vehicle 1 at a predetermined position.

Vehicle 1 belongs to a new small shuttle bus that focuses on the transportation of people and goods in the city. In the present embodiment, the new small shuttle bus is assumed to be a vehicle having a total length of 4 m to 7 m, a total width of about 2 m, and a gross vehicle weight of about 3 tons. However, the size and the gross vehicle weight are not necessarily limited to the relevant range, and may be out of the relevant range to some extent.

Further, the small shuttle bus is not necessarily limited to the transportation of people, but may be used for the transportation of goods, mobile stores, mobile offices, and the like.

Furthermore, since the small shuttle bus focuses on the transportation of people and goods in the city, it assumes a relatively low traveling speed range (maximum speed of 70 km / h or less, average speed of about 50 km / h). .. Therefore, hydroplaning measures do not have to be emphasized. However, the small shuttle bus may be used for transportation between cities and may have a high speed traveling range (for example, a maximum speed of 100 km / h).

In the present embodiment, it is assumed that the vehicle 1 is an electric vehicle having an automatic driving function (assuming level 4 or higher), but the automatic driving function is not essential and does not have to be an electric vehicle. No.

When the vehicle 1 is an electric vehicle, it is preferable to use an in-wheel motor (not shown) as a power unit. The entire unit of the in-wheel motor may be provided in the inner space of the rim wheel 100, or a part of the unit may be provided in the inner space of the rim wheel 100.

Further, when an in-wheel motor is used, it is preferable that the vehicle 1 has an independent steering function in which each wheel can be independently steered. As a result, it is possible to turn on the spot and move in the lateral direction, and since a power transmission mechanism is not required, the space efficiency of the vehicle 1 can be improved.

As described above, the vehicle 1 is required to have high space efficiency. Therefore, the pneumatic tire 10 preferably has a small diameter as much as possible.

On the other hand, since it is mounted on the vehicle 1 having a gross vehicle weight corresponding to the vehicle size and application, a high load capacity (maximum load capacity) is required.

The pneumatic tire 10 has a load-bearing capacity corresponding to the gross vehicle weight of the vehicle 1 while reducing the outer diameter OD (not shown in FIG. 1, see FIG. 2) in order to satisfy such a requirement.

Further, when the vehicle 1 is provided with an in-wheel motor and an independent steering function, it is preferable that the flatness ratio of the pneumatic tire 10 is low from the viewpoint of improving responsiveness, and considering the accommodation space of the in-wheel motor or the like, the pneumatic tire The rim diameter RD of 10 (not shown in FIG. 1, see FIG. 2) is preferably large.

(2) Configuration of Pneumatic Tire FIG. 2 is a cross-sectional view of the pneumatic tire 10 and the rim wheel 100. Specifically, FIG. 2 is a cross-sectional view of the pneumatic tire 10 assembled to the rim wheel 100 along the tire width direction and the tire diameter direction. Note that in FIG. 2, the hatching display of the cross section is omitted (the same applies to FIGS. 3 and later).

The pneumatic tire 10 has a relatively small diameter, but is wide. Specifically, the rim diameter RD, which is the diameter of the rim wheel 100 assembled to the pneumatic tire 10, is 10 inches or more and 22 inches or less. The rim diameter RD may be 12 inches or more and 17.5 inches or less in consideration of other numerical ranges.

As shown in FIG. 2, the rim diameter RD is the outer diameter of the rim body portion of the rim wheel 100, and does not include the portion of the rim flange 110.

The tire width SW of the pneumatic tire 10 is 125 mm or more and 255 mm or less. As shown in FIG. 2, the tire width SW means the cross-sectional width of the pneumatic tire 10, and when the pneumatic tire 10 includes a rim guard (not shown), the rim guard portion is not included.

Further, the flatness of the pneumatic tire 10 is 40% or more and 75% or less. The flatness is calculated using Equation 1.

Flatness (%) = tire cross-section height H / tire width SW (cross-section width) x 100 ... (Equation 1)
The outer diameter OD, which is the outer diameter of the pneumatic tire 10, is 350 mm or more and 600 mm or less. The outer diameter OD is preferably 500 mm or less.

When the outer diameter OD is such a size and the rim width of the rim wheel 100 assembled to the pneumatic tire 10 is RW, the pneumatic tire 10 satisfies the relationship of (Equation 2) and (Equation 3). .. The rim width RW is 3.8 inches or more and 8 inches or less.

0.78 ≤ RW / SW ≤ 0.99 ... (Equation 2)
0.56 ≤ RD / OD ≤ 0.75 ... (Equation 3)
The pneumatic tire 10 preferably satisfies 0.78 ≦ RW / SW ≦ 0.98, and more preferably 0.78 ≦ RW / SW ≦ 0.95. Further, the pneumatic tire 10 preferably satisfies 0.56 ≦ RD / OD ≦ 0.72, and more preferably 0.56 ≦ RD / OD ≦ 0.71.

The pneumatic tire 10 satisfying such a relationship can secure the air volume necessary for supporting the gross vehicle weight of the vehicle 1 while having a small diameter. ^{Specifically, the air volume needs to be 20,000 cm 3} or more in consideration of the load bearing performance. Further, considering space saving, it is necessary that the ^{size is 80,000 cm 3 or less.}

The rim width RW is not particularly limited as long as the above relationship is satisfied, but it is preferable that the rim width RW is as wide as possible from the viewpoint of ensuring the air volume. For example, the rim width can be 3.8 to 7.8 J.

Similarly, from the viewpoint of securing the air volume, it is preferable that the ratio of the rim diameter RD to the outer diameter OD is small, that is, the flatness is high. However, as described above, the flatness is preferably low from the viewpoint of responsiveness, and the rim diameter RD is preferably large in consideration of the accommodation space of the in-wheel motor or the like. Therefore, the flatness and the rim diameter RD Is a trade-off between air volume and responsiveness and accommodation space such as in-wheel motors.

An example of a suitable size for the pneumatic tire 10 is 205 / 40R15. The compatible rim width is about 7.5J. In addition, 215 / 45R12 is mentioned as another example of a suitable size. In this case, the compatible rim width is about 7.0J.

Further, although not particularly limited, the set internal pressure (normal internal pressure) of the pneumatic tire 10 is assumed to be 400 to 1,100 kPa, and in reality, 500 to 900 kPa. In Japan, for example, the normal internal pressure is the air pressure corresponding to the maximum load capacity of JATTA (Japan Automobile Tire Association) in the YearBook, and the regular load is the maximum load capacity (maximum) corresponding to the maximum load capacity in the JATMA YearBook. Load). ETRTO in Europe, TRA in the United States, and tire standards of other countries are supported.

Further, it is assumed that the load borne by the pneumatic tire 10 is 500 to 1,500 kgf, and in reality, about 900 kgf.

FIG. 3 is a cross-sectional view of the pneumatic tire 10. Specifically, FIG. 3 is a cross-sectional view of the pneumatic tire 10 and the rim wheel 100 along the tire width direction and the tire radial direction.

As shown in FIG. 3, the pneumatic tire 10 includes a tread 20, a tire side portion 30, a carcass 40, a belt layer 50, and a bead portion 60. As shown in FIG. 3, the cross-sectional shape of the pneumatic tire 10 is symmetrical with respect to the tire equatorial line CL as a reference.

The tread 20 is a portion in contact with the road surface. A pattern (not shown) is formed on the tread 20 according to the usage environment of the pneumatic tire 10 and the type of vehicle to be mounted.

The pattern formed on the tread 20 is not particularly limited, but in the present embodiment, a plurality of circumferential grooves are formed on the tread 20. Specifically, the tread 20 is formed with a plurality of circumferential main grooves 21. The tread 20 may be formed with a groove (lug groove) in the width direction (not shown).

The tire side portion 30 is connected to the tread 20 and is located inside the tread 20 in the tire radial direction. The tire side portion 30 is a region from the outer end of the tread 20 in the tire width direction to the upper end of the bead portion 60. The tire side portion 30 is sometimes called a sidewall or the like.

The carcass 40 is an annular member that forms the skeleton (tire skeleton) of the pneumatic tire 10. The carcass 40 has a radial structure in which carcass cords 41 (not shown in FIG. 3, see FIG. 5) arranged radially along the tire radial direction are covered with a rubber material. However, the structure is not limited to the radial structure, and a bias structure in which the carcass cords 41 are arranged so as to intersect in the tire radial direction may be used.

The material of the carcass cord 41 is not particularly limited, but is preferably formed of any of aromatic polyamide fibers, carbon fibers, and steel in consideration of the use of the pneumatic tire 10 as described above.

The belt layer 50 is provided inside the tread 20 in the tire radial direction. Specifically, the belt layer 50 is an annular shape provided between the tread 20 and the carcass 40 and extending along the tire circumferential direction.

The belt layer 50 is composed of a plurality of layers. Specifically, the belt layer 50 is composed of a first belt 51 and a second belt 52.

In the present embodiment, the first belt 51 is provided outside the tire radial direction with respect to the second belt 52.

The bead portion 60 is connected to the tire side portion 30 and is located inside the tire side portion 30 in the tire radial direction. The bead portion 60 is an annular shape extending in the tire circumferential direction, and the carcass 40 is folded back from the inside in the tire width direction to the outside in the tire width direction via the bead portion 60.

(3) Configuration of Belt Layer 50 Next, a specific configuration of the belt layer 50 will be described. FIG. 4 is a partially enlarged cross-sectional view of the belt layer 50. FIG. 5 is a partially exploded plan view of the carcass 40 and the belt layer 50.

As shown in FIGS. 4 and 5, the first belt 51 has a plurality of first cords 51a. Specifically, in the present embodiment, the first belt 51 is formed by coating the first cord 51a with a resin material.

That is, the first belt 51 is a single-layer spiral belt formed by winding the first cord 51a coated with the resin material along the tire circumferential direction. The specific configuration of the spiral belt is described in, for example, Japanese Patent Application Laid-Open No. 2018-65526.

As the resin material, a rubber material constituting the tire side portion 30 and a resin material having a higher tensile elastic modulus than the rubber material constituting the tread 20 are used. As the resin material, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. Considering the elasticity during running and the moldability during manufacturing, it is desirable to use a thermoplastic elastomer.

Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic elastomer (TPC). , Dynamic crosslinked thermoplastic elastomer (TPV) and the like.

Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, and polyamide resin. Further, as the thermoplastic resin material, for example, the deflection temperature under load (at 0.45 MPa load) specified in ISO 75-2 or ASTM D648 is 78 ° C. or higher, and the tensile yield strength specified in JIS K7113 is high. Those having a tensile fracture elongation of 10 MPa or more, a tensile fracture elongation of 50% or more specified in JIS K7113, and a Bikat softening temperature (method A) specified in JIS K7206 of 130 ° C. or more can be used.

Further, the cord itself of the first cord 51a is preferably formed of any of aromatic polyamide fibers, carbon fibers and steel.

The second belt 52 has a plurality of second cords. Specifically, the second belt 52 has a plurality of second cords 52a and a plurality of second cords 52b.

Specifically, in the present embodiment, the second belt 52 is formed by covering the second cord 52a and the second cord 52b with a resin material, similarly to the first belt 51.

As shown in FIG. 5, the first cord 51a is provided along the tire circumferential direction. On the other hand, the second cord 52a and the second cord 52b are provided so as to be inclined with respect to the tire circumferential direction.

Specifically, the second code 52a and the second code 52b are provided so as to intersect each other in the tread plane view. The second code 52a is inclined to one side with respect to the tire circumferential direction, and the second code 52b is inclined to the other side with respect to the tire circumferential direction.

By interlacing the second cord 52a and the second cord 52b, the second belt 52 constitutes the interlaced belt.

In the present embodiment, the angle θ1 formed by the second code 52a in the tire width direction is 15 degrees or more and 70 degrees or less. Similarly, the angle θ2 formed by the second code 52b in the tire width direction is also 15 degrees or more and 70 degrees or less.

The diameter φ1 of the first cord 51a is preferably larger than the diameter φ2 of the second cord. However, the diameter φ1 may be the same as the diameter φ2, but the diameter φ2 is preferably not larger than the diameter φ1.

Further, in the present embodiment, the width of the first belt 51 along the tire width direction is narrower than the width of the second belt 52 along the tire width direction. That is, the end portion of the first belt 51 in the tire width direction does not have to reach the shoulder region SH (see FIG. 3).

The shoulder region SH is a region (most in the tire width direction) outside the tire width direction from the circumferential main groove 21 formed on the outermost side in the tire width direction among the plurality of circumferential main grooves 21 formed on the tread 20. It may include the region of the circumferential main groove 21 formed on the outside).

(4) Action / Effect According to the above-described embodiment, the following action / effect can be obtained. The pneumatic tire 10 can be used for a new small shuttle bus that focuses on the transportation of people and goods in the city, like the vehicle 1 described above.

Specifically, the outer diameter OD of the pneumatic tire 10 is 350 mm or more and 600 mm or less, and the tire width SW is 125 mm or more and 255 mm or less. The flatness of the pneumatic tire 10 is 40% or more and 75% or less.

The rim diameter RD of the rim wheel 100 assembled to the pneumatic tire 10 is 10 inches or more and 22 inches or less, and the rim width RW is 3.8 inches or more and 8 inches or less.

The pneumatic tire 10 having such a size further satisfies the following relationship.

0.78 ≤ RW / SW ≤ 0.99, and 0.56 ≤ RD / OD ≤ 0.75
Therefore, the diameter is sufficiently smaller than the size of the vehicle 1, which can contribute to space saving of the vehicle 1.

Further, according to the pneumatic tire 10, in order to satisfy the relationship of 0.78 ≦ RW / SW ≦ 0.99, the rim width RW is wide with respect to the tire width SW, that is, a wide tire can be configured, and a high load capacity is possible. It is easy to secure the air volume required to exert the effect. If the rim width RW becomes too wide, the tire width SW also widens, the space efficiency decreases, and the bead portion 60 easily comes off from the rim wheel 100.

Further, according to the pneumatic tire 10, since the relationship of 0.56 ≦ RD / OD ≦ 0.75 is satisfied, the rim diameter RD with respect to the outer diameter OD is large, and it is easy to secure a storage space for an in-wheel motor or the like. If the rim diameter RD becomes too small, the diameter size of the disc brake or the drum brake becomes small. Therefore, the effective contact area of the brake becomes small, and it becomes difficult to secure the required braking performance.

That is, according to the pneumatic tire 10, when it is mounted on a new small shuttle bus or the like, it is possible to achieve high space efficiency while having a higher load capacity.

Further, since the rim diameter RD of the pneumatic tire 10 is 10 inches or more and 22 inches or less, it is possible to secure a necessary and sufficient storage space for an air volume and an in-wheel motor while maintaining a small diameter. In addition, braking performance and driving performance can be ensured.

Further, the tire width SW of the pneumatic tire 10 is 125 mm or more and 255 mm or less, and the flatness of the pneumatic tire 10 is 40% or more and 75% or less. Storage space can be secured.

In this embodiment, the belt layer 50 includes a first belt 51 and a second belt 52. Further, the first code 51a is provided along the tire circumferential direction, and the second code 52a and the second code 52b are provided so as to be inclined with respect to the tire circumferential direction. Further, the diameter φ1 of the first cord 51a is larger or the same as the diameter φ2 of the second cord 52a and the second cord 52b.

Since the pneumatic tire 10 has the size as described above, the air volume filled in the internal space of the pneumatic tire 10 assembled to the rim wheel 100 is reduced, and the internal pressure is increased to support a high load. Set.

Therefore, in particular, the shoulder portion of the tread 20 on which the belt layer 50 is not provided tends to grow in the tire radial direction due to the high internal pressure, but the tread 20 is provided along the tire circumferential direction and has a first cord 51a having a large diameter. By combining the first belt 51 and the second belt 52 having the second cord 52a and the second cord 52b provided so as to be inclined with respect to the tire circumferential direction, a portion other than the shoulder region SH (called a center region). By suppressing the growth in the tire radial direction, the growth (diameter growth) of the shoulder region SH in the tire radial direction can be further suppressed as a result.

That is, according to the pneumatic tire 10, it is possible to improve the durability against a high internal pressure while achieving a high load-bearing capacity and space saving.

In the present embodiment, the first belt 51 is formed by coating the first cord 51a with a resin material. Further, the second belt 52 is also formed by coating the second cord 52a and the second cord 52b with a resin material. Therefore, the first belt 51 and the second belt formed of a resin material having a high tensile elastic modulus. According to 52, the diameter growth can be effectively suppressed even when the pneumatic tire 10 is set to a high internal pressure.

In the present embodiment, the angle θ1 and the angle θ2 formed by the second code 52a and the second code 52b in the tire width direction are 15 degrees or more and 70 degrees or less. Therefore, the diameter growth can be achieved by combining the first cord 51a provided along the tire circumferential direction with the second cord 52a and the second cord 52b having an angle formed with the tire width direction of 15 degrees or more and 70 degrees or less. Can be effectively suppressed. In particular, in the present embodiment, since the second code 52a and the second code 52b are provided so as to intersect with each other, it is more effective in suppressing the diameter growth.

In the present embodiment, the first belt 51 is provided outside the tire radial direction with respect to the second belt 52. Further, the width of the first belt 51 along the tire width direction is narrower than the width of the second belt 52 along the tire width direction. Therefore, the belt durability can be enhanced by the combination of the first belt 51 and the second belt 52.

If the belt has the same width as the first belt 51, it is effective in suppressing the diameter growth, but the rigidity of the shoulder region SH becomes excessive, which may adversely affect the belt durability and the like.

(5) Other Embodiments Although the embodiments have been described above, it is obvious to those skilled in the art that various modifications and improvements are possible without being limited to the description of the embodiments.

FIG. 6 is a partially enlarged cross-sectional view of the belt layer 50A according to the first modification. As shown in FIG. 6, the belt layer 50A is composed of the first belt 51 and the second belt 52, similarly to the belt layer 50. However, in the belt layer 50A, the first belt 51 is provided inside the tire radial direction with respect to the second belt 52.

Further, in the belt layer 50A, the width of the first belt 51 along the tire width direction is wider than the width of the second belt 52 along the tire width direction.

Further, a reinforcing member 53 is provided inside the first belt 51 in the tire radial direction. The reinforcing member 53 reinforces the shoulder region SH (see FIG. 3) of the first belt 51 in the tire width direction.

The reinforcing member 53 is provided only in the shoulder region SH. Specifically, the reinforcing member 53 is separately provided in one shoulder region SH and the other shoulder region SH in the tire width direction (in FIG. 6, only one shoulder region SH is shown).

The reinforcing member 53 has a plurality of reinforcing cords 53a. The reinforcing cord 53a may be provided along the tire circumferential direction in the same manner as the first cord 51a. However, the reinforcing cord 53a does not necessarily have to be along the tire circumferential direction. That is, the reinforcing cord 53a may be inclined with respect to the tire circumferential direction.

Further, the reinforcing member 53 may be formed by covering the reinforcing cord 53a with a resin material, similarly to the first belt 51. The diameter of the reinforcing cord 53a is not particularly limited, but may be the same as the diameter φ2 of the second cord 52a and the second cord 52b, that is, smaller than the diameter φ1 of the first cord 51a.

FIG. 7 is a partially enlarged cross-sectional view of the belt layer 50B according to the second modification. As shown in FIG. 7, the belt layer 50B is composed of the first belt 51 and the second belt 52, similarly to the belt layer 50A according to the first modification. Even in the belt layer 50B, the first belt 51 is provided inside the tire radial direction with respect to the second belt 52.

A reinforcing member 54 is provided inside the first belt 51 in the tire radial direction. The reinforcing member 54 reinforces the shoulder region SH (see FIG. 3) of the first belt 51 in the tire width direction, similarly to the reinforcing member 53 according to the first modification.

The reinforcing member 54 is not separated like the reinforcing member 53 according to the first modification, and is provided from one end to the other end of the tread 20 (see FIG. 3) in the tire width direction.

The reinforcing member 54 has a plurality of reinforcing cords 54a. The structure and material of the reinforcing member 54 may be the same as that of the reinforcing member 53.

Similar to the belt layer 50, the belt layer 50A and the belt layer 50B can also improve the durability against a high internal pressure while achieving high load bearing capacity and space saving.

Further, in the above-described embodiment, both the first belt 51 and the second belt 52 are formed by using a resin material, but at least one of the first belt 51 and the second belt 52 is necessarily made of a resin material. It may not be formed using, for example, it may be formed using a rubber material.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure may be implemented as an amendment or modification without departing from the purpose and scope of the present disclosure, which is determined by the description of the scope of claims. Therefore, the description of the present disclosure is for the purpose of exemplary explanation and does not have any limiting meaning to the present disclosure.

1 Vehicle 10 Pneumatic tire 20 Tread 21 Circumferential main groove 30 Tire side part 40 Carcus 41 Carcus cord 50, 50A, 50B Belt layer 51 1st belt 51a 1st code 52 2nd belt 52a 2nd code 52b 2nd code 53 Reinforcing member 53a Reinforcing cord 54 Reinforcing member 54a Reinforcing cord 100 Rim wheel 110 Rim flange

Claims (7)

A pneumatic tire with a belt layer inside the tread that contacts the road surface in the radial direction.
The outer diameter OD of the pneumatic tire is 350 mm or more and 600 mm or less.
The tire width SW of the pneumatic tire is 125 mm or more and 255 mm or less.
The flatness of the pneumatic tire is 40% or more and 75% or less.
The rim diameter RD of the rim wheel assembled to the pneumatic tire is 10 inches or more and 22 inches or less.
The rim width RW of the rim wheel is 3.8 inches or more and 8 inches or less.
0.78 ≤ RW / SW ≤ 0.99, and 0.56 ≤ RD / OD ≤ 0.75
Meet the relationship,
The belt layer is
A first belt with multiple first cords and
Including at least a second belt having a plurality of second cords,
The first cord is provided along the tire circumferential direction and is provided.
The second cord is provided so as to be inclined with respect to the tire circumferential direction.
A pneumatic tire in which the diameter of the first cord is the same as or larger than the diameter of the second cord. The pneumatic tire according to claim 1, wherein the first belt is formed by coating the first cord with a resin material. The pneumatic tire according to claim 1 or 2, wherein the angle formed by the second cord in the tire width direction is 15 degrees or more and 70 degrees or less. The pneumatic tire according to any one of claims 1 to 3, wherein the second belt is formed by coating the second cord with a resin material. The first belt is provided outside the tire radial direction with respect to the second belt.
The pneumatic tire according to any one of claims 1 to 4, wherein the width of the first belt along the tire width direction is narrower than the width of the second belt along the tire width direction. The first belt is provided inside the tire radial direction with respect to the second belt.
The pneumatic tire according to any one of claims 1 to 4, wherein a reinforcing member for reinforcing the shoulder region in the tire width direction of the first belt is provided inside the tire radial direction of the first belt. The first belt is provided inside the tire radial direction with respect to the second belt.
The pneumatic tire according to any one of claims 1 to 4, wherein the width of the first belt along the tire width direction is wider than the width of the second belt along the tire width direction.

Images