Pneumatic tire

Abstract

To provide a pneumatic tire which can effectively suppress uneven wear, while achieving high load resistance capability and space saving.SOLUTION: An outer diameter of a pneumatic tire (10) is 350 mm or more and 600 mm or less, when a rim width of a rim wheel (100) assembled with the pneumatic tire (10) is represented by RW and a tire width of the pneumatic tire (10) is represented by SW, they satisfy a relation of 0.78≤RW / SW≤0.99, and a tread is formed with at least two circumferential main grooves extending in a tire circumferential direction. The circumferential main grooves are formed on a side closer to a tire equator line (tire equator line CL) than a tire width direction outer end of a belt layer.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a small diameter pneumatic tire having an increased load-bearing capacity. [Background technology]

[0002] Conventionally, pneumatic tires that have a small diameter while increasing the load-bearing capacity (maximum load capacity) are known (see Patent Document 1). It is said that such pneumatic tires can save space, particularly in small vehicles, and ensure a large passenger space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-138435 A Summary of the Invention

[0004] However, small-diameter pneumatic tires as described above have a short contact length and a small contact area relative to the load they must support, which means that they are prone to uneven contact pressure. Such uneven contact pressure can cause uneven wear.

[0005] In recent years, new small shuttle buses have been proposed that are primarily intended for transporting people and goods within cities. These small shuttle buses are expected to be about 5m long and 2m wide, with a total vehicle weight exceeding 3t. Space-saving pneumatic tires are also required for these small shuttle buses.

[0006] Therefore, the present invention has been made in consideration of the above circumstances, and has an object to provide a pneumatic tire that can effectively suppress uneven wear while achieving high load-bearing capacity and space saving.

[0007] One aspect of the present invention is a pneumatic tire (pneumatic tire 10) that is fitted to a vehicle (vehicle 1) and includes a tread (tread 20) that contacts a road surface and a belt layer (belt layer 50) that is provided on the radially inward side of the tread, the pneumatic tire having an outer diameter of 350 mm or more and 600 mm or less, and satisfying a relationship of 0.78≦RW / SW≦0.99, where RW is the rim width of a rim wheel (rim wheel 100) that is mounted to the pneumatic tire and SW is the tire width of the pneumatic tire, and at least two circumferential main grooves (circumferential main grooves 21, 22) that extend in the circumferential direction of the tire are formed in the tread, and the circumferential main grooves are formed closer to a tire equator line (tire equator line CL) than the outer end of the belt layer in the tire width direction. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic overall side view of a vehicle 1 on which a pneumatic tire 10 is mounted. [Diagram 2] FIG. 2 is a cross-sectional view of the pneumatic tire 10 and the rim wheel 100. [Diagram 3] FIG. 3 is a cross-sectional view of the pneumatic tire 10 alone. [Figure 4] FIG. 4 is a partially developed plan view of the tread 20. As shown in FIG. [Diagram 5] FIG. 5 is a diagram showing typical tire size positioning based on the combination of tire shape (tire outer diameter OD and tire width SW) and rim wheel shape (rim diameter RD and rim width RW). [Figure 6] FIG. 6 is a cross-sectional view of a pneumatic tire 10A according to a modified example. [Figure 7] FIG. 7 is a cross-sectional view of a pneumatic tire 10B according to another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and the description thereof will be omitted as appropriate.

[0010] (1) General configuration of a vehicle on which pneumatic tires are installed Fig. 1 is a schematic overall side view of a vehicle 1 on which a pneumatic tire 10 according to this embodiment is mounted. As shown in Fig. 1, in this embodiment, the vehicle 1 is a four-wheeled automobile. Note that the vehicle 1 is not limited to having four wheels, and may have six or eight wheels, for example.

[0011] A predetermined number of pneumatic tires 10 are mounted on the vehicle 1 according to the wheel configuration. Specifically, the pneumatic tires 10 assembled to rim wheels 100 are mounted on the vehicle 1 at predetermined positions.

[0012] Vehicle 1 belongs to a new type of small shuttle bus that is primarily intended for transporting people and goods within cities. In this embodiment, the new small shuttle bus is assumed to be a vehicle with an overall length of 4 m to 7 m, an overall width of about 2 m, and a total vehicle weight of about 3 tons. However, the size and total vehicle weight are not necessarily limited to these ranges, and may deviate from these ranges to some extent.

[0013] Furthermore, the small shuttle bus is not necessarily limited to being used for transporting people, but may also be used for transporting goods, as a mobile store, a mobile office, etc.

[0014] Furthermore, since small shuttle buses are primarily intended for transporting people and goods within cities, they are expected to operate at a relatively low speed range (maximum speed 70 km / h or less, average speed around 50 km / h). For this reason, measures against hydroplaning do not need to be given much importance.

[0015] In this embodiment, the vehicle 1 is assumed to be an electric vehicle equipped with an autonomous driving function (assuming level 4 or higher), but the autonomous driving function is not essential, and the vehicle does not have to be an electric vehicle.

[0016] When the vehicle 1 is an electric vehicle, it is preferable to use an in-wheel motor (not shown) as the power unit. The in-wheel motor may be provided as a whole unit 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.

[0017] Furthermore, when using in-wheel motors, it is preferable that the vehicle 1 has an independent steering function that allows each wheel to be steered independently. This allows the vehicle 1 to turn around on the spot and move laterally, and also eliminates the need for a power transmission mechanism, improving the space efficiency of the vehicle 1.

[0018] Thus, high space efficiency is required in the vehicle 1. For this reason, it is preferable that the pneumatic tire 10 has as small a diameter as possible.

[0019] On the other hand, since the vehicle 1 will have a total vehicle weight appropriate for the vehicle size and use, a high load-bearing capacity (maximum load capacity) is required.

[0020] In order to satisfy these requirements, the pneumatic tire 10 has a small tire outer diameter OD (not shown in FIG. 1, see FIG. 2) and a load-bearing capacity corresponding to the total vehicle weight of the vehicle 1.

[0021] Furthermore, when the vehicle 1 is equipped with an in-wheel motor and an independent steering function, it is preferable for the aspect ratio of the pneumatic tire 10 to be low from the viewpoint of improving responsiveness, and in consideration of the storage space for the in-wheel motor, etc., it is preferable for the rim diameter RD (not shown in FIG. 1, see FIG. 2) of the pneumatic tire 10 to be large.

[0022] (2) Structure of pneumatic tires 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 along the tire width direction and tire radial direction of the pneumatic tire 10 mounted on the rim wheel 100. Note that hatching of the cross section is omitted in Fig. 2 (the same applies to Fig. 3 and subsequent figures).

[0023] The pneumatic tire 10 has a relatively small diameter but is wide. Specifically, the rim diameter RD of the rim wheel 100 is preferably 12 inches or more and 17.5 inches or less. However, the rim diameter RD may be 10 inches or more and 22 inches or less as long as other numerical ranges are satisfied.

[0024] As shown in FIG. 2, the rim diameter RD is the outside diameter of the rim body portion of the rim wheel 100 and does not include the rim flange 110 portion.

[0025] Moreover, the tire width SW of the pneumatic tire 10 is preferably 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 does not include the rim guard portion when the pneumatic tire 10 includes a rim guard (not shown).

[0026] Furthermore, it is preferable that the aspect ratio of the pneumatic tire 10 is 35% or more and 75% or less.

[0027] Aspect ratio (%) = tire section height H / tire width SW (section width) x 100 ... (Formula 1) The tire outer diameter OD of the pneumatic tire 10 is 350 mm or more and 600 mm or less. The tire outer diameter OD is preferably 500 mm or less.

[0028] When the tire outer diameter OD is of this size and the rim width of the rim wheel 100 mounted on the pneumatic tire 10 is taken as the rim width RW, the pneumatic tire 10 satisfies the relationships of (Equation 2) and (Equation 3).

[0029] 0.78≦RW / SW≦0.99…(Formula 2) 0.56≦RD / OD≦0.75…(Formula 3) The pneumatic tire 10 preferably satisfies 0.78≦RW / SW≦0.98, and more preferably satisfies 0.78≦RW / SW≦0.95. The pneumatic tire 10 preferably satisfies 0.56≦RD / OD≦0.72, and more preferably satisfies 0.56≦RD / OD≦0.71.

[0030] The pneumatic tire 10 that satisfies such a relationship can ensure the air volume necessary to support the total weight of the vehicle 1, even though it has a small diameter. Specifically, the air volume is 20,000 cm3, taking into account the load support performance. 3 In addition, if space saving is taken into consideration, 80,000 cm is required. 3 The following is required:

[0031] As long as the above relationship is satisfied, the rim width RW is not particularly limited, but from the viewpoint of ensuring air volume, it is preferable that the rim width is as wide as possible. For example, the rim width may be 3.8 to 7.8J.

[0032] Similarly, from the viewpoint of ensuring air volume, it is preferable that the ratio of the rim diameter RD to the tire outer diameter OD is small, that is, the aspect ratio is high. However, as described above, from the viewpoint of responsiveness, a low aspect ratio is preferable, and considering the accommodation space for an in-wheel motor, etc., a large rim diameter RD is preferable, so the aspect ratio and the rim diameter RD are in a trade-off relationship between the air volume, and the responsiveness and the accommodation space for an in-wheel motor, etc.

[0033] An example of a suitable size for the pneumatic tire 10 is 205 / 40R15. The suitable rim width is about 7.5J. Another example of a suitable size is 215 / 45R12. In this case, the suitable rim width is about 7.0J.

[0034] Furthermore, 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 more realistically, 500 to 900 kPa. Note that the normal internal pressure is, for example, the air pressure that corresponds to the maximum load capacity in the YearBook of the Japan Automobile Tire Manufacturers Association (JATMA) in Japan, the ETRTO in Europe, the TRA in the United States, and tire standards of other countries.

[0035] The load borne by the pneumatic tire 10 is assumed to be 500 to 1,500 kgf, and realistically, approximately 900 kgf.

[0036] 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 taken along the tire width direction and the tire radial direction.

[0037] 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.

[0038] The tread 20 is the portion that comes into contact with the road surface. The tread 20 has a pattern (see FIG. 4) formed thereon according to the environment in which the pneumatic tire 10 is used and the type of vehicle on which it is mounted.

[0039] In this embodiment, two circumferential main grooves extending in the tire circumferential direction are formed in the tread 20. Note that more circumferential grooves may be formed in the tread 20, and widthwise grooves extending in the tire width direction may be formed. In addition, the circumferential grooves and the widthwise grooves may form blocks that come into contact with the road surface. The shape of the blocks in the tread surface view is not particularly limited.

[0040] Specifically, a circumferential main groove 21 and a circumferential main groove 22 are formed in the tread 20. The circumferential main groove 21 and the circumferential main groove 22 are formed closer to the tire equator line CL than an outer end 50e of the belt layer 50 in the tire width direction.

[0041] Furthermore, if the distance between the inner end of the circumferential main groove 21 in the tire width direction and the outer end of the circumferential main groove 22 in the tire width direction is W, and the thickness (rubber gauge) of the tread 20 at the position of the tire equator line CL is H, it is preferable to satisfy 1.5≦W / H≦6.0, and it is more preferable to satisfy 2.0≦W / H≦4.0.

[0042] The tire side portion 30 is continuous with the tread 20 and is located on the inner side in the tire radial direction of the tread 20. 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 also called a sidewall or the like.

[0043] The carcass 40 forms the framework of the pneumatic tire 10. The carcass 40 has a radial structure in which carcass cords (not shown) arranged radially along the tire radial direction are covered with a rubber material. However, the carcass 40 is not limited to a radial structure, and may have a bias structure in which the carcass cords are arranged to cross each other in the tire radial direction.

[0044] The belt layer 50 is provided on the tire radial direction inner side of the tread 20. In this embodiment, the belt layer 50 is a three-belt configuration, but may be a four-belt configuration. Specifically, the belt layer 50 includes a pair of interlaced belts in which cords interlace. The configuration of such a belt layer 50 is generally similar to the configuration of a belt layer of a general truck / bus tire.

[0045] The bead portion 60 is continuous with the tire side portion 30 and is located on the tire radially inner side of the tire side portion 30. The bead portion 60 has an annular shape extending in the tire circumferential direction, and the carcass 40 is folded back via the bead portion 60 from the inner side in the tire width direction to the outer side in the tire width direction.

[0046] In addition, a bead filler may be provided on the bead portion 60 radially outside of the bead core, and a chafer may be provided to prevent the carcass 40, which is folded over at the bead portion 60, from rubbing against the rim wheel 100 and becoming worn.

[0047] (3) Position and shape of circumferential main groove 4 is a partially developed plan view of the tread 20. As shown in FIG 4, in the tread 20, a plurality of blocks are formed by the circumferential main grooves 21 and the circumferential main grooves 22.

[0048] Specifically, the tread 20 is formed with a center block 23 , a shoulder block 24 and a shoulder block 25 .

[0049] The central block 23 is formed in an area including the tire equator line CL. A circumferential main groove 21 and a circumferential main groove 22 are formed at ends of the central block 23 in the tire width direction.

[0050] Shoulder blocks 24 are formed on the outer side in the tire width direction of the circumferential main groove 21. Shoulder blocks 25 are formed on the outer side in the tire width direction of the circumferential main groove 22.

[0051] In this embodiment, the circumferential main grooves 21 and 22 are formed in a range of 25% to 95% of the width from the tire equator line CL to the tire width direction outer end 50e of the belt layer 50, assuming that the width is 100%. The circumferential main grooves 21 and 22 are preferably formed in a range of 35% to 85%, and more preferably formed in a range of 40% to 70%.

[0052] The circumferential main groove 21 and the circumferential main groove 22 may have any specific shape, such as a straight groove, a zigzag groove, or a curved groove, as long as they extend in the tire circumferential direction.

[0053] In addition, since the traveling speed range of the vehicle 1 is low, there is no need to increase the groove area as a countermeasure against hydroplaning, but on the other hand, it is necessary to improve the wear performance, so the negative ratio of the tread 20 is preferably 5% or more and 25% or less. The negative ratio of the tread 20 is more preferably 7% or more and 20% or less, and further preferably 9% or more and 15% or less.

[0054] In order to achieve both braking performance on wet road surfaces and wear performance, it is preferable to form sipes in the central block 23 defined by the circumferential main groove 21 and the circumferential main groove 22. The interval between the sipes in the tire circumferential direction is preferably 1.5 to 5.0 times the sipe depth, and more preferably 2.0 to 4.0 times the sipe depth.

[0055] Furthermore, in order to achieve both braking performance on wet roads and wear performance, the number of circumferential main grooves is preferably 2 to 4. The groove width of the circumferential main groove is preferably 2 to 20 mm, and more preferably 3 to 15 mm.

[0056] (4) Actions and Effects Next, a description will be given of the operation and effect of the above-mentioned pneumatic tire 10. Fig. 5 is a diagram showing the positioning of typical tire sizes based on the combination of the tire shape (tire outer diameter OD and tire width SW) and the rim / wheel shape (rim diameter RD and rim width RW).

[0057] Specifically, the horizontal axis of the graph shown in Fig. 5 indicates the ratio (RW / SW) between the rim width RW and the tire width SW, and the vertical axis indicates the ratio (RD / OD) between the rim diameter RD and the tire outer diameter OD. In Fig. 5, the positions of typical tire sizes are plotted according to the values ​​of RW / SW and RD / OD.

[0058] As shown in Figure 5, the areas of truck and bus tires are lower in both RW / SW and RD / OD. The areas of passenger car or light truck tires are higher than truck and bus tires in both RW / SW and RD / OD.

[0059] The above-mentioned 215 / 45R12, which is an example of a suitable size for the pneumatic tire 10, is included in the region A1. As described above, the region A1 is in the range of 0.78≦RW / SW≦0.99 and 0.56≦RD / OD≦0.75. Such region A1 is positioned as the region for tires for new small shuttle buses that are primarily intended for transporting people and goods within cities, such as the above-mentioned vehicle 1.

[0060] The RD / OD of the new small shuttle bus tire area is not significantly different from the RD / OD of the passenger car or small truck tire area, and there is some overlap, while the RW / SW of the new small shuttle bus tire area is higher than the RW / SW of the passenger car or small truck tire area.

[0061] As described above, the tire outer diameter OD of the pneumatic tire 10 is equal to or greater than 350 mm and equal to or less than 600 mm. Therefore, the tire outer diameter OD is sufficiently small compared to the size of the vehicle 1, and can contribute to space saving of the vehicle 1.

[0062] Furthermore, according to the pneumatic tire 10 of the size included in the region A1, the relationship of 0.78≦RW / SW≦0.99 is satisfied, so the rim width RW is wide relative to the tire width SW, meaning that a wide tire can be constructed, making it easy to ensure the air volume necessary to exhibit a high load-bearing capacity. However, if the rim width RW becomes too wide, the tire width SW also widens, reducing the space efficiency, and the bead portion 60 becomes more likely to come off the rim wheel 100.

[0063] Furthermore, according to the pneumatic tire 10 having a size included in the region A1, the relationship of 0.56≦RD / OD≦0.75 is satisfied, so that the rim diameter RD is large relative to the tire outer diameter OD, and it is easy to secure the space to accommodate an in-wheel motor, etc. However, if the rim diameter RD becomes too small, the diameter size of the disc brake or drum brake becomes small. As a result, the effective contact area of ​​the brake becomes small, making it difficult to secure the required braking performance.

[0064] That is, the pneumatic tire 10 can achieve high space efficiency while having a higher load-bearing capacity when mounted on a new small shuttle bus or the like.

[0065] The rim diameter RD of the pneumatic tire 10 is preferably 12 inches or more and 17.5 inches or less. This makes it possible to secure a necessary and sufficient air volume and a space for accommodating an in-wheel motor, etc., while maintaining a small diameter. In addition, braking performance and driving performance can be secured.

[0066] The tire width SW of the pneumatic tire 10 is preferably 125 mm or more and 255 mm or less. Furthermore, the aspect ratio of the pneumatic tire 10 is preferably 35% or more and 75% or less. This makes it possible to ensure a necessary and sufficient air volume and storage space for an in-wheel motor, etc.

[0067] Furthermore, in this embodiment, as described above, the circumferential main grooves 21 and 22 extending in the tire circumferential direction are formed, and the circumferential main grooves 21 and 22 are formed closer to the tire equator line CL than the tire width direction outer end 50e of the belt layer 50.

[0068] That is, the circumferential main grooves 21 and 22 are formed in an area where the ground pressure is particularly high in the small-diameter, wide pneumatic tire 10. This ensures an "escape route" for the rubber forming the tread 20 in the area where the ground pressure is high. This makes it possible to effectively suppress uneven wear in that area.

[0069] That is, the pneumatic tire 10 can effectively suppress uneven wear while achieving high load-bearing capacity and space-saving.

[0070] In this embodiment, the circumferential main grooves 21 and 22 are formed in a range of 25% to 95% of the width from the tire equator line CL to the tire width direction outer end 50e of the belt layer 50, assuming that the width is 100%. Therefore, the circumferential main grooves 21 and 22 are formed in an area where the ground pressure is particularly high. This makes it possible to more effectively suppress uneven wear in that area.

[0071] (5) Other embodiments The present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and it will be obvious to those skilled in the art that various modifications and improvements are possible.

[0072] For example, the configuration of the pneumatic tire 10 may be modified as follows: Fig. 6 is a cross-sectional view of a pneumatic tire 10A according to a modified example.

[0073] 6, the pneumatic tire 10A includes a belt layer 50A. The belt layer 50A is composed of a core belt 51 and a sheath vest 52.

[0074] The core belt 51 is a belt in which a cord (not shown) inclined at a low angle with respect to the tire width direction is rubber-coated. The sheath vest 52 is a tape-like belt including a cord, and is wound around the entire circumference of the core belt 51. The belt layer 50A provides the same function as the intersecting belt layer.

[0075] The specific configuration of the sheath vest 52 is described in, for example, JP 2016-215943 A.

[0076] In the pneumatic tire 10A, the folded end 41 of the carcass 40 folded back at the bead portion 60 is provided so as to be wound around the bead core 61. The folded end 41 is in contact with the outer end of the bead core 61 in the tire radial direction. Although not shown in FIG. 6, the bead portion 60 may be provided with a bead filler.

[0077] Fig. 7 is a cross-sectional view of a pneumatic tire 10B according to another modified example. As shown in Fig. 7, the pneumatic tire 10B includes a belt layer 50B. The belt layer 50B is a spiral belt formed by winding a resin-coated cord coated with a resin material in the tire circumferential direction.

[0078] The pneumatic tires 10A and 10B also have circumferential main grooves 21 and 22 formed therein similar to those of the pneumatic tire 10.

[0079] As in the pneumatic tires 10A and 10B, the configuration of the belt layers and the shape of the folded end portion 41 of the carcass 40 may be changed as appropriate depending on the characteristics of the vehicle 1 and the like.

[0080] In addition, in the above-described embodiment, the pneumatic tire 10 satisfies the relationship 0.56≦RD / OD≦0.75, but this relationship does not necessarily have to be satisfied.

[0081] As described above, the embodiment of the present invention has been described, but the description and drawings forming a part of this disclosure should not be understood as limiting this invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art. [Explanation of symbols]

[0082] 1 vehicle 10, 10A, 10B Pneumatic tires 20 Tread 21, 22 Circumferential main groove 23 Central Block 24, 25 Shoulder Block 30 Tire side 40 Carcass 41 Folded end 50, 50A, 50B belt layer 50e Outer end in tire width direction 51 Core Belt 52 Sheath Vest 60 Bead section 61 Bead core 100 Rim Wheel 110 Rim flange

Claims

1. A pneumatic tire to be mounted on a vehicle includes a tread that contacts a road surface and a belt layer provided on a radially inner side of the tread, The outer diameter of the pneumatic tire is 350 mm or more and 600 mm or less, The rim width of the rim wheel to be mounted on the pneumatic tire is RW, If the tire width of the pneumatic tire is SW, The relationship 0.78≦RW / SW≦0.99 is satisfied. The tread is formed with at least a first circumferential main groove extending in a tire circumferential direction and a second circumferential main groove adjacent to the first circumferential main groove in a tire width direction, A pneumatic tire that satisfies 1.5≦W / H≦6.0, where W is the distance between an inner end of the first circumferential main groove in the tire width direction and an inner end of the second circumferential main groove in the tire width direction, and H is the thickness of the rubber of the tread at the position of the tire equator line.

2. 2. The pneumatic tire according to claim 1, wherein the set internal pressure of the pneumatic tire is 400 to 1,100 kPa.

3. 3. The pneumatic tire according to claim 1, wherein the load borne by the pneumatic tire is 500 to 1,500 kgf.

4. 4. The pneumatic tire according to claim 1, wherein the air volume of the pneumatic tire is equal to or greater than 20,000 cm3 and equal to or less than 80,000 cm3.

5. The number of circumferential main grooves including the first circumferential main groove and the second circumferential main groove is two or more and four or less, The pneumatic tire according to claim 1 , wherein the circumferential main groove has a groove width of 2 mm or more and 20 mm or less.

6. The pneumatic tire according to claim 1 , wherein the negative ratio of the tread is equal to or greater than 5% and equal to or less than 25%.

7. The pneumatic tire according to claim 1 , wherein a sipe is formed in a central block defined by the first circumferential main groove and the second circumferential main groove.

8. 8. The pneumatic tire according to claim 1, wherein, when an outer diameter of the pneumatic tire is OD and a rim diameter of the pneumatic tire is RD, a relationship of 0.56≦RD / OD≦0.75 is satisfied.

9. The pneumatic tire according to claim 1 , wherein the belt layer is constituted by a core belt and a sheath vest.

10. The pneumatic tire according to any one of claims 1 to 9, wherein the pneumatic tire is a tire for a truck or bus.

Images