Pneumatic tire

Abstract

To provide a pneumatic tire which improves abrasion resistant performance and riding comfort performance in a specific tire size.SOLUTION: A rim diameter RD of a rim R of a pneumatic tire is 12-17 inches. A ratio SH / SW of a cross section height SH of the tire to a cross section width SW of the tire is 0.30-0.45. A ratio RW / SW of a rim width RW of the rim to the cross section width SW of the tire is 0.78-0.99. A complex elastic modulus E*1 (MPa) of a cap rubber layer 15 is higher than a complex elastic modulus E*2 (MPa) of a base rubber layer 16. In a belt ply, a plurality of belt cords 7c having flexural rigidity M (g cm) are arranged with the number n of driven-in cords per ply width 5 cm. The complex elastic modulus E*1, the complex elastic modulus E*2, the flexural rigidity M, and the number n of driven-in cords satisfy the following formula (1): M×n<(E*1 / E*2)×3,000 ...(1)SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] In recent years, various small buses have been proposed for the purpose of transporting people and goods in urban areas (for example, see Patent Document 1 below). Such vehicles are required to have a large interior space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-075088 Summary of the Invention [Problem to be solved by the invention]

[0004] The tires installed on such small buses need to have a small outer diameter in order to maximize the interior space of the vehicle. On the other hand, since these tires are subjected to high loads, they are required to have excellent wear resistance. Furthermore, from the viewpoint of improving passenger comfort, the tires are also required to have an excellent ride comfort.

[0005] The present invention has been devised in view of the above-mentioned circumstances, and has as its main object to provide a pneumatic tire having improved wear resistance and ride comfort for a specific tire size. [Means for solving the problem]

[0006] The present invention provides a pneumatic tire that is mounted on a rim for use, the rim having a rim diameter RD of 12 to 17 inches, a ratio SH / SW of a tire's section height SH to a tire's section width SW of 0.30 to 0.45, and a ratio RW / SW of a tire's rim width RW to a tire's section width SW of 0.78 to 0.99, the pneumatic tire having a tread portion, the tread portion including a tread rubber and a belt layer consisting of two belt plies arranged on the tire radially inward side of the tread rubber, the tread rubber being a joining layer. The pneumatic tire includes a cap rubber layer that forms the ground and a base rubber layer disposed radially inward of the cap rubber layer, the complex modulus E*1 (MPa) of the cap rubber layer is greater than the complex modulus E*2 (MPa) of the base rubber layer, the belt ply has a plurality of belt cords having a bending rigidity M (g·cm) and is arranged with a thread count n (pieces) per 5 cm of ply width, and the complex modulus E*1, the complex modulus E*2, the bending rigidity M and the thread count n satisfy the relationship of the following formula (1): M×n<(E*1 / E*2)×3000 …(1) Effect of the Invention

[0007] By adopting the above-described configuration, the pneumatic tire of the present invention can improve wear resistance and ride comfort. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a pneumatic tire according to one embodiment of the present invention. [Diagram 2] 1 is a perspective view of a vehicle on which a tire according to the present invention is mounted. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of the tread portion of FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of an end of the belt ply of FIG. 3. [Diagram 5] FIG. 4 is an enlarged cross-sectional view of the groove and tread rubber of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described based on the drawings. The drawings are described to include the features of the present invention, but may contain exaggerated expressions or expressions different from the dimensional ratios of the actual structure in order to facilitate understanding of the present invention. In addition, the same or common elements are given the same reference numerals throughout each embodiment, and duplicated explanations are omitted. In addition, well-known configurations can be appropriately adopted for configurations not described in this specification.

[0010] Fig. 1 shows a cross-sectional view of a pneumatic tire 1 (hereinafter, may be simply referred to as "tire 1") showing one embodiment of the present invention. Fig. 2 is a perspective view conceptually showing a vehicle Ve on which the tire 1 of the present invention is mounted. As shown in Figs. 1 and 2, the tire 1 of this embodiment is mounted on a rim R and used, and is suitably used as a pneumatic tire for a vehicle Ve such as a small bus or a small shuttle bus.

[0011] As shown in Fig. 2, the vehicle Ve described above is a four-wheeled vehicle. Note that the vehicle Ve is not limited to having four wheels, and may have six or eight wheels. In addition, a predetermined number of tires 1 are mounted on the vehicle Ve according to the wheel configuration.

[0012] The vehicle Ve belongs to the category of small shuttle buses used for transporting people and goods within a city, for example. The small shuttle bus is assumed to be a vehicle with a total length of 4 m to 7 m, a total width of about 2 m, and a total vehicle weight of about 3 tons. However, the tire 1 of the present invention is not limited to being used on vehicles in the above-mentioned range, but can be used on various vehicles.

[0013] Furthermore, the vehicle Ve 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, and the like. It is preferable that the vehicle Ve is, for example, an electric vehicle equipped with an automatic driving function. Furthermore, since the vehicle Ve is primarily intended for transporting people and goods within cities, it is assumed that the vehicle will travel at a relatively low driving speed range (average speed of about 50 km / h). For this reason, wet performance may not be emphasized. However, the vehicle Ve is not limited to such an embodiment.

[0014] If the vehicle Ve is an electric vehicle, it is preferable that the motor is disposed inside the rim. In this case, it is also preferable that the vehicle Ve has an independent steering function that allows each wheel to be steered independently. This makes it easier to turn on the spot and increases the interior space of the vehicle Ve.

[0015] The tire 1 of this embodiment used on such a vehicle Ve is required to have high space efficiency. Therefore, the tire 1 is required to have a small rim diameter and a small tire cross-sectional height. On the other hand, since the vehicle Ve has a certain weight, the tire 1 is also required to have high wear resistance. In addition, the vehicle Ve is also required to have excellent ride comfort.

[0016] FIG. 1 is a cross-sectional view including the axis of rotation of a tire 1 in a normal state. In the case of a pneumatic tire for which various standards are established, the "normal state" refers to a state in which the tire is mounted on a normal rim, inflated to a normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established, the normal state refers to a standard use state according to the intended use of the tire, in which the tire is not mounted on a vehicle and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal state. In addition, the dimensions of components that cannot be measured in the normal state (for example, the internal materials of the tire 1) are values ​​measured with the tire 1 in a state as close as possible to the normal state.

[0017] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0018] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0019] The tire 1 includes a tread portion 2, a pair of sidewall portions 3, and a pair of bead portions 4. The sidewall portions 3 are connected to the axially outer side of the tread portion 2 and extend in the radial direction of the tire. The bead portions 4 are connected to the radially inner side of the sidewall portions 3. The tire 1 also includes a carcass 6. The carcass 6 extends between the pair of bead portions 4. In other words, the carcass 6 extends from one bead portion 4 through one sidewall portion 3, the tread portion 2, and the other sidewall portion 3 to the other bead portion 4.

[0020] The carcass 6 is composed of, for example, two carcass plies 6A and 6B. These carcass plies include, for example, a main body portion 6a and a turned-up portion 6b. The main body portion 6a extends, for example, between the pair of bead portions 4. The turned-up portion 6b is, for example, continuous with the main body portion 6a and is turned up around the bead core 5 from the inner side to the outer side in the tire axial direction.

[0021] The carcass plies 6A, 6B include a plurality of carcass cords and a topping rubber covering the carcass cords (not shown). The carcass cords are made of organic fiber such as aramid or rayon. The carcass cords are desirably arranged at an angle of 70 to 90° with respect to the tire equator C. However, the tire 1 of the present invention is not limited to this embodiment.

[0022] In the present invention, the rim diameter RD of the rim R is 12 to 17 inches. Furthermore, the ratio SH / SW of the tire's section height SH to the tire's section width SW is 0.30 to 0.45. The ratio RW / SW of the rim width RW of the rim R to the tire's section width SW is 0.78 to 0.99. The section width SW is, for example, 150 to 250 mm.

[0023] The rim diameter RD is the outer diameter of the rim body portion that is fitted by the bead core 5 of the bead portion 4. The cross-sectional width SW of the tire 1 corresponds to the width excluding any protrusions (not shown) indicating patterns or letters on the sidewall of the tire 1. The cross-sectional height SH of the tire 1 corresponds to half the difference between the outer diameter of the tire and the rim diameter RD. In other words, the cross-sectional height SH corresponds to the distance in the tire radial direction from the bead baseline BL to the outer end of the tire 1 in the tire radial direction. The bead baseline BL refers to the tire axial line that passes through the rim diameter position.

[0024] The rim width RW of the rim R corresponds to the distance in the tire axial direction from the inner surface of one rim flange Rf to the inner surface of the other rim flange Rf. If the inner surface is inclined, the distance is measured at the center position in the tire radial direction of the bead core 5 when the tire 1 is mounted on the rim R.

[0025] As described above, the tire 1 of the present invention has a relatively small rim diameter RD and section height SH, and a relatively large rim width RW relative to the tire section width SW. Such a tire 1 increases the space efficiency in the vehicle space when mounted on the above-mentioned vehicle Ve (shown in FIG. 2), and can ensure sufficient storage space for a motor in a vehicle in which the motor is disposed inside the rim. In addition, such a tire 1 can hold a sufficient air volume to support the total weight of the vehicle.

[0026] Fig. 3 shows an enlarged cross-sectional view of the tread portion 2 of the tire 1 of Fig. 1. As shown in Fig. 3, the tread portion 2 includes a tread rubber 2G and a belt layer 7 consisting of two belt plies arranged on the inner side of the tread rubber 2G in the tire radial direction.

[0027] The belt layer 7 of this embodiment is composed of a first belt ply 11 adjacent to the carcass 6 and a second belt ply 12 arranged on the tire radially outer side of the first belt ply 11. FIG. 4 shows an enlarged cross-sectional view of the end of these belt plies. As shown in FIG. 4, the belt ply includes a plurality of belt cords 7c arranged at an angle of 15 to 45 degrees with respect to the tire circumferential direction, and a topping rubber 7g covering these. The belt cords of the first belt ply 11 and the belt cords of the second belt ply 12 are inclined in opposite directions to each other with respect to the tire circumferential direction. This effectively reinforces the tread portion 2.

[0028] In the first belt ply 11 and the second belt ply 12, a plurality of belt cords 7c having a bending stiffness M (g cm) are arranged with a count n (pieces) per 5 cm of the ply width. As a desirable aspect, in this embodiment, a plurality of belt cords 7c having substantially the same bending stiffness M are arranged in the first belt ply 11 and the second belt ply 12. Moreover, in the first belt ply 11 and the second belt ply 12, the belt cords 7c are uniformly arranged.

[0029] The "bending stiffness M" is measured by cutting the belt cord 7c to a length of 70 mm so as not to untwist the cord, and taking a test piece, using, for example, a stiffness tester (Model 150-D) manufactured by Taba Corporation, USA. Specifically, one end of the test piece is fixed, and a force F is applied to the other end of the test piece extending 50 mm from the fixed end, and the resistance (bending stiffness) is measured when the opening angle at the other end of the test piece becomes 15°.

[0030] As shown in Fig. 3, the tread rubber 2G includes a cap rubber layer 15 constituting the ground contact surface 2s, and a base rubber layer 16 disposed radially inward of the cap rubber layer 15. In the present invention, the complex modulus E*1 (MPa) of the cap rubber layer 15 is greater than the complex modulus E*2 (MPa) of the base rubber layer 16. In this specification, the complex modulus is a value measured using a viscoelasticity spectrometer under the following conditions in accordance with the provisions of JIS-K6394. Initial distortion: 10% Amplitude: ±2% Frequency: 10Hz Deformation mode: tension Measurement temperature: 30℃

[0031] In the pneumatic tire 1 of the present invention, the complex modulus E*1 of the cap rubber layer 15, the complex modulus E*2 of the base rubber layer 16, the bending rigidity M of the belt cord 7c, and the end count n of the belt cord 7c satisfy the relationship of the following formula (1). As a result, the pneumatic tire of the present invention can improve wear resistance and ride comfort. The reason is as follows. M×n<(E*1 / E*2)×3000 …(1)

[0032] The inventors have found that the product of the bending rigidity M and the number of threads n of the belt cords 7c in the belt layer 7 is greatly related to the rigidity of the tread portion 2, and has a large effect on the wear resistance and ride comfort. The inventors have also found that the larger the ratio (E*1 / E*2) of the complex modulus of elasticity of the cap rubber layer 15 and the base rubber layer 16, the more the vibration absorbing properties of the tread portion 2 are improved, contributing to improved ride comfort. Furthermore, the inventors have focused on the relationship between these parameters, and as a result of various experiments, have identified the relationship of the above-mentioned formula (1). By satisfying this relationship, the vibration absorbing properties of the tread portion 2 are sufficiently ensured against the restraining force of the tread portion 2 by the belt layer 7, and the wear resistance and ride comfort can be improved.

[0033] In the present invention, in order to allow for variation in the above-mentioned parameters (the complex elastic modulus E*1, the complex elastic modulus E*2, the bending rigidity M, and the number of threads n), it is desirable to apply the average value of each parameter to the formula (1). Note that the "average value of each parameter" is calculated, for example, by dividing the measurement object into a number of micro-areas of appropriate size, measuring the corresponding parameters for each micro-area, and dividing the sum of the obtained parameters for each micro-area by the number of divided micro-areas.

[0034] A more detailed configuration of this embodiment will be described below. Each configuration described below shows a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the tire of the present invention having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0035] From the viewpoint of achieving a balanced improvement in wear resistance and ride comfort, the left side of formula (1), "M×n," is desirably 40% or more, and more desirably 50% or more, of the right side of formula (1), "(E*1 / E*2)×3000," and is desirably 80% or less, and more desirably 70% or less.

[0036] Each of the belt cords 7c (shown in FIG. 4) is preferably a steel cord. The bending rigidity M of the belt cords 7c is preferably 100 g·cm or more, more preferably 120 g·cm or more, even more preferably 130 g·cm or more, and is preferably 300 g·cm or less, more preferably 200 g·cm or less, and even more preferably 190 g·cm or less. This improves abrasion resistance and ride comfort in a well-balanced manner.

[0037] The end count n (pieces) of the belt cord 7c per 5 cm of the ply width of the belt ply is, for example, 10 to 30 pieces, and preferably 23 to 27 pieces.

[0038] Each of the belt cords 7c has a tensile strength T (N). The tensile strength T is preferably 1000N or more, more preferably 1300N or more, and preferably 2000N or less, more preferably 1700N or less. This improves abrasion resistance and ride comfort in a well-balanced manner. The "tensile strength T" is the maximum load required to break a test piece measured at a tensile speed of 5 cm / min in accordance with the tensile test of the breaking load and total elongation at break (section 6.4) in the "Test Method for Steel Tire Cords" of JIS G3510.

[0039] In a more preferable embodiment, the complex elastic modulus E*1, the complex elastic modulus E*2, the tensile strength T, and the thread count n satisfy the relationship of the following formula (2). By satisfying this relationship, ride comfort performance can be reliably improved. T×n<(E*1 / E*2)×35000 …(2)

[0040] From the viewpoint of achieving a well-balanced improvement in wear resistance and ride comfort, the left side of formula (2), "T×n," is desirably 40% or more, more desirably 50% or more, of the right side of formula (2), "(E*1 / E*2)×35000," and is desirably 80% or less, and more desirably 70% or less.

[0041] The complex elastic modulus E*1 of the cap rubber layer 15 is preferably 8.0 MPa or more, more preferably 9.0 MPa or more, and preferably 15.0 MPa or less, and more preferably 12.0 MPa or less. The complex elastic modulus E*2 of the base rubber layer 16 is preferably 4.0 MPa or more, more preferably 4.5 MPa or more, and preferably 9.0 MPa or less, and more preferably 7.0 MPa or less. This provides sufficient wear resistance.

[0042] The complex elastic modulus E*1 of the cap rubber layer 15 is preferably 1.5 to 2.5 times, and more preferably 1.8 to 2.2 times, the complex elastic modulus E*2 of the base rubber layer 16. This makes it possible to suppress peeling between the cap rubber layer 15 and the base rubber layer 16 while achieving the above-mentioned effects.

[0043] The average thickness t2 of the cap rubber layer 15 is preferably 70% to 95% of the average thickness t1 of the tread rubber 2G. The average thickness t3 of the base rubber layer 16 is preferably 5% to 30% of the average thickness t1 of the tread rubber 2G. This improves the balance between wear resistance and ride comfort. The average thickness t1 of the tread rubber 2G corresponds to the value obtained by dividing the cross-sectional area of ​​the tread rubber 2G in a region radially inward of the contact surface 2s of the tread portion 2 by the axial length of the tread rubber 2G in said region. The same applies to the average thickness t2 of the cap rubber layer 15 and the average thickness t3 of the base rubber layer 16.

[0044] The tread portion 2 includes at least one groove 17. FIG. 5 shows an enlarged cross-sectional view of the groove 17 and the tread rubber 2G. As shown in FIG. 5, the groove 17 provided in the tread portion 2 includes a groove bottom 17d and a treadwear indicator 18 that protrudes locally from the groove bottom 17d. The treadwear indicator 18 is a minute protrusion that indicates the limit of wear of the tread portion 2, and has a height of, for example, 1.6 mm. For ease of understanding, in FIG. 5, a dot is applied to the treadwear indicator 18. Note that the treadwear indicator 18 is omitted in FIG. 1 and FIG. 3.

[0045] In a desirable embodiment, the outer surface 16s in the tire radial direction of the base rubber layer 16 is located radially inward of the outer surface 18s in the tire radial direction of the treadwear indicator 18. More specifically, the entire outer surface 16s of the base rubber layer 16 is located radially inward of an imaginary line 19 that passes through the outer surface 18s of the treadwear indicator 18 and extends along the contact surface 2s of the tread portion 2. As a result, the cap rubber layer 15 forms the outer surface of the tread portion 2 until the end of wear of the tread portion 2, so that excellent wear resistance performance is exhibited for a long period of time.

[0046] Although the pneumatic tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-mentioned specific embodiment and can be modified and implemented in various aspects. EXAMPLES

[0047] A pneumatic tire of size 205 / 40R15 having the basic structure shown in FIG. 1 was prototyped based on the specifications in Table 1. In addition, a tire not satisfying the above formula (1) was prototyped as a comparative example. The comparative tire was substantially the same as the example tire except for the above points. The ride comfort performance and wear resistance performance of each test tire were tested. The common specifications and test methods of each test tire are as follows: Rim: 15×7.0J Tire pressure: 520kPa Test vehicle: e-Pallet manufactured by Toyota Motor Corporation

[0048] <Ride comfort performance> The ride comfort performance when the test vehicle equipped with the test tires was driven was evaluated by the driver's senses. The results are rated based on the ride comfort performance of the comparative example being 100, with a higher value indicating a better ride comfort performance.

[0049] <Wear resistance> The wear energy was measured when each test tire was run on a GPS tester. The results are expressed as an index with the reciprocal of the wear energy of the comparative example being 100, and the larger the value, the smaller the wear energy and the more excellent the wear resistance. The test results are shown in Table 1.

[0050] [Table 1]

[0051] [Table 2]

[0052] When the ratio C / A shown in Tables 1 and 2 is smaller than 1, the relationship of the above formula (1) is satisfied. Also, when the ratio D / B shown in Tables 1 and 2 is smaller than 1, the relationship of the above formula (2) is satisfied. As shown in Tables 1 and 2, the tires of each example have significantly improved wear resistance and ride comfort. In other words, it was confirmed that the present invention improves wear resistance and ride comfort in a specific tire size.

[0053] [Note] The present invention includes the following aspects.

[0054] [Invention 1] A pneumatic tire that is mounted on a rim and used, The rim diameter RD of the rim is 12 to 17 inches, The ratio SH / SW of the tire's section height SH to the tire's section width SW is 0.30 to 0.45, a ratio RW / SW of a rim width RW of the rim to a section width SW of the tire is 0.78 to 0.99; The pneumatic tire has a tread portion, The tread portion includes a tread rubber and a belt layer including two belt plies arranged on the inner side of the tread rubber in the tire radial direction, The tread rubber includes a cap rubber layer that forms a ground contact surface, and a base rubber layer that is disposed radially inward of the cap rubber layer, The complex elastic modulus E*1 (MPa) of the cap rubber layer is greater than the complex elastic modulus E*2 (MPa) of the base rubber layer, The belt ply is made up of a plurality of belt cords having a bending rigidity M (g cm) and arranged with a number n (pieces) per 5 cm of ply width, The complex elastic modulus E*1, the complex elastic modulus E*2, the bending rigidity M, and the number of threads n satisfy the relationship of the following formula (1), Pneumatic tires. M×n<(E*1 / E*2)×3000 …(1) [Invention 2] Each of the plurality of belt cords has a tensile strength T(N), The pneumatic tire according to invention 1, wherein the complex modulus E*1, the complex modulus E*2, the tensile strength T, and the number of threads per tire n satisfy the relationship of the following formula (2). T×n<(E*1 / E*2)×35000 …(2) [Invention 3] 3. The pneumatic tire according to claim 2, wherein the tensile strength T is 1000 to 2000 N. [Invention 4] The pneumatic tire according to any one of claims 1 to 3, wherein the average thickness of the base rubber layer is 5% to 30% of the average thickness of the tread rubber. [Invention 5] The tread portion includes at least one groove, the groove includes a groove bottom and a treadwear indicator locally protruding from the groove bottom; The pneumatic tire according to any one of claims 1 to 3, wherein an outer surface in the radial direction of the tire of the base rubber layer is located inward in the radial direction of the tire with respect to an outer surface in the radial direction of the tire of the treadwear indicator. [Invention 6] 4. The pneumatic tire according to any one of claims 1 to 3, wherein the complex modulus E*1 is 8.0 to 15.0 MPa. [Invention 7] 4. The pneumatic tire according to any one of claims 1 to 3, wherein the complex modulus E*2 is 4.0 to 9.0 MPa. [Invention 8] 4. The pneumatic tire according to any one of claims 1 to 3, wherein each of the plurality of belt cords is a steel cord. [The present invention 9] 9. The pneumatic tire according to invention 8, wherein the bending rigidity M is 100 to 300 g·cm. [Explanation of symbols]

[0055] 2 Tread section 2G Tread rubber 7 Belt layer 15 Cap rubber layer 16 Base rubber layer R Rim RD rim diameter SW Tire section width SH Tire section height RW rim width E*1 Complex modulus of the cap rubber layer E*2 Complex modulus of the base rubber layer

Claims

1. A pneumatic tire that is mounted on a rim and used, The rim diameter RD of the rim is 12 to 17 inches, a ratio SH / SW of the tire's section height SH to the tire's section width SW is 0.30 to 0.45; a ratio RW / SW of a rim width RW of the rim to a cross-sectional width SW of the tire is 0.78 to 0.99; The pneumatic tire has a tread portion, The tread portion includes a tread rubber and a belt layer including two belt plies arranged on the inner side of the tread rubber in the tire radial direction, The tread rubber includes a cap rubber layer that forms a ground contact surface, and a base rubber layer that is disposed radially inward of the cap rubber layer, The complex elastic modulus E*1 (MPa) of the cap rubber layer is greater than the complex elastic modulus E*2 (MPa) of the base rubber layer, In the belt ply, a plurality of belt cords having a bending rigidity M (g cm) are arranged with a number n (pieces) per 5 cm of ply width, The complex elastic modulus E*1, the complex elastic modulus E*2, the bending rigidity M, and the number of threads n satisfy the relationship of the following formula (1), Pneumatic tires. M×n<(E*1 / E*2)×3000…(1)

2. Each of the plurality of belt cords has a tensile strength T (N), The pneumatic tire according to claim 1 , wherein the complex modulus E*1, the complex modulus E*2, the tensile strength T, and the number of threads per tire n satisfy the relationship of the following formula (2). T×n<(E*1 / E*2)×35000…(2)

3. 3. The pneumatic tire according to claim 2, wherein the tensile strength T is 1000 to 2000 N.

4. 4. The pneumatic tire according to claim 1, wherein an average thickness of the base rubber layer is 5% to 30% of an average thickness of the tread rubber.

5. The tread portion includes at least one groove, the groove includes a groove bottom and a treadwear indicator locally protruding from the groove bottom; The pneumatic tire according to claim 1 , wherein an outer surface in a radial direction of the base rubber layer is located radially inward of an outer surface in the radial direction of the treadwear indicator.

6. The pneumatic tire according to any one of claims 1 to 3, wherein the complex elastic modulus E*1 is 8.0 to 15.0 MPa.

7. The pneumatic tire according to any one of claims 1 to 3, wherein the complex elastic modulus E*2 is 4.0 to 9.0 MPa.

8. The pneumatic tire according to claim 1 , wherein each of the plurality of belt cords is a steel cord.

9. The pneumatic tire according to claim 8, wherein the bending rigidity M is 100 to 300 g·cm.

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