pneumatic tires

Abstract

Pneumatic tires, comprising: an annular tread portion (1) extending in the tire circumferential direction; a pair of sidewall portions (2) arranged on both sides of the tread portion (1); a pair of bead portions (3) arranged inwardly of the sidewall portions (2) in the tire radial direction; a carcass portion disposed between a pair of tire bead portions (3); a plurality of belt layers (7) arranged on an outer periphery of the carcass layer (4) in the tread portion (1); a band-shaped noise absorbing member (10) attached to an inner surface of the tread portion (1) along the tire circumferential direction; at least one complete cover layer (8f) arranged on an outer peripheral side of the plurality of belt layers (7) and covering an entire width of the plurality of belt layers (7); and a middle cover layer (8c) arranged on an outer peripheral side of the complete cover layer (8f) and covering a central region of the plurality of belt layers (7) in the tire width direction in places; wherein the belt cover layers (8, 8c, 8f) each contain organic fiber cords oriented in an angular range of 0° to 5° inclusive to the tire circumferential direction; wherein a width SW of the band-shaped sound absorbing element (10) and a width BW of the plurality of belt layers (7) satisfy a ratio SW / BW = 0.3 to 0.8, wherein a width CW of the middle cover layer (8c) and the width SW of the band-shaped sound-absorbing element (10) satisfy a ratio CW / SW = 0.05 to 0.35, - wherein a mounting direction is given with respect to a vehicle; - wherein an outer side of a tire equator (CL) with respect to the vehicle is a vehicle outer side when the pneumatic tire is mounted on the vehicle, and wherein an inner side of the tire equator (CL) with respect to the vehicle is a vehicle inner side when the pneumatic tire is mounted on the vehicle; and - where a width SW OUT a section of the band-shaped noise-absorbing element (10) on the vehicle exterior, a width SW IN a section of the band-shaped noise-absorbing element (10) on the vehicle interior, and the width CW of the middle cover layers (8c) the ratios SW IN / CW < 5, SW OUT / CW < 8, and SW IN / SWOUT < 0.9.

Description

Technical area

[0001] The present invention relates to a pneumatic tire equipped with a tire noise reduction device, and more particularly, to a pneumatic tire that can achieve sufficient quietness by means of a band-shaped noise absorbing member attached to a tire inner surface and prevent a reduction in high-speed durability caused by accumulation of heat in the band-shaped noise absorbing member at high speeds. State of the art

[0002] One source of noise is cavity resonance, which is caused by vibration of the air in the cavity (tire cavity) when the tire is mounted on a rim. When a vehicle is driving, uneven road surfaces cause a tread portion to vibrate PS:mo upon contact with the road surface, generating cavity resonance. A certain frequency range of cavity resonance is perceived as noise, so to reduce tire noise, it is important to reduce the sound pressure level (noise level) in this frequency range.

[0003] As a method for reducing noise, it has been proposed to incorporate a sound-absorbing member made of a porous material such as sponge or the like into the tire cavity. For example, in the pneumatic tire described in JP 5267288 B2, it has been proposed to provide a band-shaped sound-absorbing member bonded to an inner peripheral surface of the tread portion with an adhesive. However, with such a structure, the sound-absorbing member is directly attached to the tire's inner surface, so that heat can easily build up in the tread portion at high speeds. This accumulated heat can lead to a reduction in high-speed durability. Other prior art documents include DE 11 2014 006 241 T5, DE 10 2012 214 866 A1, and CN 1 02 001 263 A. Brief description of the invention

[0005] Technical problem

[0004] It is an object of the present invention to provide a pneumatic tire incorporating a tire noise reduction device, the pneumatic tire being capable of achieving sufficient quietness by means of a band-shaped noise absorbing member attached to the tire inner surface and preventing any reduction in high-speed durability caused by the accumulation of heat in the band-shaped noise absorbing member at high speeds.

[0006] Solution to the problem

[0005] In order to achieve the above-described object, a pneumatic tire according to an embodiment of the present invention is a pneumatic tire including: an annular tread portion extending in the tire circumferential direction; a pair of sidewall portions arranged on both sides of the tread portion; a pair of bead portions arranged inboard of the sidewall portions in the tire radial direction; a carcass portion disposed between a pair of tire bead portions; a plurality of belt layers arranged on an outer periphery of the carcass layer in the tread portion; a band-shaped noise absorbing member attached to an inner surface of the tread portion along the tire circumferential direction; at least one complete cover layer arranged on an outer peripheral side of the plurality of belt layers and covering an entire width of the plurality of belt layers; and a middle cover layer disposed on an outer circumferential side of the entire cover layer and partially covering a central region of the plurality of belt layers in the tire width direction; wherein the belt cover layers each include organic fiber cords oriented at an angular range of 0° to 5° inclusive to the tire circumferential direction. A width SW of the band-shaped sound-absorbing member and a width BW of the plurality of belt layers satisfy a ratio SW / BW = 0.3 to 0.8, and a width CW of the middle cover layer and the width SW of the band-shaped sound-absorbing member satisfy a ratio CW / SW = 0.05 to 0.35;wherein a mounting direction is given with respect to a vehicle, and wherein an outer side of a tire equator with respect to the vehicle is a vehicle outer side when the pneumatic tire is mounted on the vehicle, and wherein an inner side of the tire equator with respect to the vehicle is a vehicle inner side when the pneumatic tire is mounted on the vehicle; and wherein a width SWOUT of a portion of the band-shaped sound absorbing member on the vehicle outer side, a width SWIN of a portion of the band-shaped sound absorbing member on the vehicle inner side, and the width CW of the middle cover layers satisfy the relationships SWIN / CW < 5, SWOUT / CW < 8, and SWIN / SWOUT < 0.9; Advantageous effects of the invention

[0006] The present invention includes a middle cover layer whose width CW corresponds to the width BW of the belt layers and the width SW of the sound-absorbing member. Consequently, swelling of the belt layers at high speed can be effectively reduced, and even in a state where heat buildup is likely to occur when the sound-absorbing member is directly attached, a reduction in high-speed durability as a result of this heat buildup can be prevented. In particular, the width SW of the sound-absorbing member is set within an appropriate range with respect to the width BW of the belt layers, so that the sound-absorbing effect is effectively exhibited while maintaining sufficient durability of the sound-absorbing member itself.Furthermore, the width CW of the middle cover layer is set within a reasonably small range with respect to the width SW of the noise-absorbing member, so that the increase in rigidity resulting from the addition of the middle cover layer is reduced, and ride comfort and quietness can be maintained to an appropriate degree. As a result, the deterioration of high-speed durability can be effectively prevented while maintaining excellent quietness.

[0007] In this way, for vehicles on which the tires are mounted for intended high-speed driving with a negative camber, the heat build-up on the vehicle interior where the build-up is easy to occur is effectively reduced relatively easily, and the effect of improving high-speed durability by the middle cover layer can be successfully demonstrated.

[0008] In one embodiment of the present invention, a mounting direction is determined with respect to a vehicle; and when the pneumatic tire is mounted on the vehicle, an outer side of a tire equator with respect to the vehicle is a vehicle outer side, and when the pneumatic tire is mounted on the vehicle, an inner side of the tire equator with respect to the vehicle is a vehicle inner side. Preferably, a cross-sectional area SA OUT a section of the band-shaped noise absorbing element on the vehicle interior, and a cross-sectional area SA IN a portion of the band-shaped noise absorbing member on the vehicle interior, and a cross-sectional area T of a tire cavity satisfy the relationships 0 ≤ SA IN / t ≤ 0.2 and 0.1 ≤ SA OUT / t ≤ 0.4 (t = T / 2). In this way, for vehicles on which tires are installed for intended high-speed driving with negative camber, the heat buildup on the vehicle interior, where buildup is prone to occur, is effectively reduced relatively easily, and the effect of improving high-speed durability by the middle cover layer can be successfully demonstrated.

[0009] In one embodiment of the present invention, the middle cover layer is preferably made of organic fiber cords in which nylon fibers and aramid fibers are interwoven. In this way, durability can be effectively improved due to the properties of the composite fiber cords made of nylon fibers and aramid fibers.

[0010] In one embodiment of the present invention, the band-shaped sound-absorbing member preferably includes a recessed portion at least at a portion in the tire circumferential direction. This enables the band-shaped sound-absorbing member to withstand tire deformation (tire expansion) during inflation and shear strain of the gripping surface due to ground rolling over a long period of time.

[0011] In the present invention, each dimension and cross-sectional area of ​​the tire are measured when the tire is mounted on a regular rim and inflated with air to the normal internal pressure. Specifically, in each case, the width of each element is the length in the width direction between the two ends of the elements in this state. Note that the "width BW" of the belt layers is the width of the belt layer located on the outermost circumferential side among the plurality of belt layers. Furthermore, the "cross-sectional area of ​​the tire cavity" is the cross-sectional area in a meridian cross section of the cavity portion formed between the tire and the rim in this state.A "regular rim" is a rim defined by a standard for each tire according to a system of standards that includes standards on which tires are based, and refers to a "standard rim" in the case of the Japan Automobile Tire Manufacturers Association (JATMA), a "design rim" in the case of the Tire and Rim Association (TRA), and a "measuring rim" in the case of the European Tire and Rim Technical Organization (ETRTO)."Normal internal pressure" is the air pressure defined by standards for each tire according to a system of standards that includes standards on which tires are based, and refers to a "maximum air pressure" in the case of JATMA, the maximum value in the "TIRE ROAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" table in the case of TRA, and the "INFLATION PRESSURE" in the case of ETRTO. However, the air pressure marked on the vehicle is used if the tire is an original equipment tire.A "regular load" is a load defined by a standard for each tire according to a system of standards that includes standards on which tires are based and refers to a "maximum load capacity" in the case of JATMA, to the maximum value in the table "TIRE ROAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA and to a "LOAD CAPACITY" in the case of ETRTO. Brief description of the drawings Fig. 1 is a perspective cross-sectional view of a pneumatic tire according to an embodiment of the present invention. Fig. 2 is a meridian cross-sectional view showing the pneumatic tire of Fig. 1 represents. Fig. 3 is a meridian cross-sectional view showing Fig. 2 to describe the cross-sectional area of ​​each part. Fig. 4 is a cross-sectional view of a pneumatic tire according to an embodiment of the present invention, taken from an equatorial line. Description of embodiments

[0012] The configuration of the present invention will be explained in detail below with reference to the accompanying drawings.

[0013] The reference symbol CL in Fig. 1 denotes a tire equator. The pneumatic tire according to one embodiment of the present invention includes an annular tread portion 1 extending in the tire circumferential direction, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged inwardly of the sidewall portions 2 in the tire radial direction.

[0014] A carcass layer 4 is interposed between the pair of left-right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction and is folded back from a vehicle inner side to a vehicle outer side around a bead core 5 disposed in each of the bead portions 3. Furthermore, bead fillers 6 are disposed on the periphery of the bead cores 5, and each bead filler 6 is enclosed by a main body portion and a folded-back portion of the carcass layer 4. In the tread portion 1, a plurality of belt layers 7 (two layers in the illustrated example) are embedded on an outer circumferential side of the carcass layer 4.These belt layers 7 each include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the directions of the reinforcing cords of the different layers overlap each other.

[0015] In one embodiment of the present invention, in this typical pneumatic tire, a belt cover layer 8 is provided on the outer peripheral side of the belt layers 7, as described later, and a band-shaped sound absorbing member 10 is mounted on a tire inner surface, as described later. The basic structure of the pneumatic tire without the belt cover layer 8 and the band-shaped sound absorbing member 10 is not limited to the structure described above.

[0016] In the present invention, a plurality of belt cover layers 8 are provided on the outer peripheral side of the belt layers 7, as described above. However, this plurality of belt cover layers 8 must include at least one (in the illustrated example, there is one layer) complete cover layer on the belt layer 7 side so as to cover the entire width of the belt layers 7, and a center cover layer 8c arranged on the outer peripheral side of the complete cover layer 8f, which locally covers a central region in the tire width direction of the belt layers 7. Note that in the illustrated example, edge cover layers 8e are also provided, which are arranged on the outer peripheral side of the complete cover layer 8f and locally cover two end portions in the tire width direction of the belt layers 7.The belt cover layers 8 each include organic fiber cords oriented in the tire circumferential direction, and the organic fiber cords are oriented at an angle of, for example, 0° to 5° with respect to the tire circumferential direction. Note that there is no particular limitation on the type of organic fiber cords, but at least for the middle cover layer 8c, organic fiber cord obtained by interlacing nylon fibers and aramid fibers is preferably used in order to effectively reduce the swelling of the belt layers 7 at high speeds at locations greatly affected by heat buildup, as described later.

[0017] In one embodiment of the present invention, the band-shaped sound-absorbing member 10 is provided on the tire inner surface as described above. The band-shaped sound-absorbing member 10 is made of a porous material with open cells and has predetermined sound absorption properties based on the porous structure. For example, polyurethane foam can be used as the porous material of the band-shaped sound-absorbing member 10. The band-shaped sound-absorbing member 10 is bonded to a region of the tire inner surface corresponding to the tread portion 1 by means of, for example, an adhesive layer 11. For example, double-sided adhesive tape is preferably used as the adhesive layer 11.

[0018] By providing the belt cover layer 8 and the band-shaped noise absorbing member 10 in this manner, as shown in Fig.2, a width of the belt layer 7 is BW, a width of the middle cover layer 8c between the cover layers 8 is CW, and a width of the band-shaped sound absorbing members 10 is SW, and the width BW of the belt layers 7 is set to from 0.3 to 0.8, and the ratio CW / SW of the width CW of the middle cover layer 8c and the width SW of the band-shaped sound absorbing member 10 is set to from 0.05 to 0.35.

[0019] In this way, in a tire in which the band-shaped sound-absorbing member 10 is directly attached to the tire inner surface in a manner that is prone to heat buildup, the center cover layer 8c is provided so that the swelling of the belt layers 7 at high speed can be reduced and the reduction in high-speed durability due to heat buildup can be prevented. In this case, the width SW of the band-shaped sound-absorbing member 10 is set corresponding to the width BW of the belt layers 7, and in addition, the width CW of the center cover layer 8c is set corresponding to the width SW of the band-shaped sound-absorbing member 10.As a result, high-speed swelling is effectively reduced by the middle cover layer 8c, while the band-shaped sound-absorbing member 10 demonstrates good low noise performance, so that a reduction in high-speed durability caused by heat buildup can be prevented. Specifically, the width SW of the band-shaped sound-absorbing member 10 is set within an appropriate range with respect to the width BW of the belt layers 7, so that the sound-absorbing effect of the band-shaped sound-absorbing member 10 is effectively exhibited while maintaining sufficient durability of the band-shaped sound-absorbing member 10 itself.Furthermore, the width CW of the middle cover layer 8c is set within a reasonably small range with respect to the width SW of the belt-shaped sound-absorbing member 10, so that the increase in rigidity resulting from the addition of the middle cover layer 8c is reduced, and ride comfort and quietness can be maintained to an appropriate extent. As a result, the deterioration of high-speed durability can be effectively prevented while maintaining excellent quietness.

[0020] If the SW / BW ratio is less than 0.3, sufficient mass of the band-shaped sound-absorbing member 10 cannot be provided, thus reducing the sound-absorbing performance and making it difficult to achieve sufficient low noise. It should be noted that, in conjunction with these ratios regarding widths, in a case where the thickness of the band-shaped sound-absorbing member 10 is increased, sufficient mass of the band-shaped sound-absorbing member 10 can be provided, but the band-shaped sound-absorbing member 10 becomes larger (bulkier) in terms of adhesion area, thereby reducing durability. If the SW / BW ratio is greater than 0.8, peeling is likely to occur from both ends in the width direction of the band-shaped sound-absorbing member 10, thereby reducing durability.In order to provide better quietness while maintaining sufficient durability of the belt-shaped noise absorbing member 10 itself, the SW / BW ratio can be set within a range, for example, from 0.5 to 0.7. If the CW / SW ratio is less than 0.05, the center cover layer 8c is too small, so that a sufficient reinforcing effect cannot be achieved by the center cover layer 8c, and the effect of reducing the swelling of the belt layer 7 at high speeds is limited. In other words, the deterioration of durability at high speeds cannot be sufficiently prevented. If the CW / SW ratio is greater than 0.35, the rigidity of the tread portion 1 is excessively high, and ride comfort and quietness are adversely affected.In order to more effectively prevent swelling of the belt layer 7 at high speeds without excessively increasing the rigidity of the tread portion 1, the ratio CW / SW may be set, for example, in the range of 0.1 to 0.25.

[0021] For vehicles designed for high-speed travel, tires are typically mounted with negative camber. When the mounting direction is designed for this purpose, the heat buildup of the tread portion at high speeds tends to differ between the side on an outer side of the tire equator when mounted on the vehicle (vehicle outside) and the side on the inner side of the tire equator when mounted on the vehicle (vehicle inside). Specifically, heat buildup occurs more easily on the vehicle inside than on the vehicle outside. As a result, the band-shaped sound-absorbing member 10, which is likely to cause heat buildup, is shifted toward the vehicle outside, so that the heat buildup element (band-shaped sound-absorbing member 10) on the side where heat buildup is more likely to occur is reduced.

[0022] More precisely, as in Fig.2, the width of the section of the band-shaped noise absorbing element 10 on the vehicle outer side SW OUT , and the width of the section of the band-shaped sound absorbing member 10 on the vehicle interior is SW IN , and the ratio SW IN / CW of width SW IN and the width CW of the middle cover layer 8c is less than 5 (SW IN / CW < 5), the ratio SW OUT / CW of width SW OUT and the width CW of the middle deck view 8c is less than 8 (SW OUT / CW < 8), and the ratio SW IN / SW OUT the width SW IN and the width SW OUT is less than 0.9 (SW IN / SW OUT< 0.9). By setting the width of each section of each element within the appropriate range in this way, for vehicles on which tires intended for high-speed travel are mounted with negative camber, the heat build-up on the vehicle interior, where build-up is likely to occur, is effectively reduced relatively easily, and the effect of improving high-speed durability by the middle cover layer 8c can be successfully demonstrated. If the ratio SW IN / CW is greater than 5, the width of the portion of the band-shaped sound absorbing member 10 on the vehicle interior is too large relative to the middle cover layer 8c, and the band-shaped sound absorbing member 10 located on the vehicle interior where heat buildup is likely to occur in the case of negative camber cannot be sufficiently reduced, whereby a sufficient effect of reducing heat buildup cannot be achieved. If the ratio SW OUT / CW is greater than 8, the width of the portion of the band-shaped sound-absorbing member 10 on the vehicle exterior side is too large relative to the middle cover layer 8c, so that peeling is likely to occur from the end portions of the band-shaped sound-absorbing member 10 on the vehicle exterior side, and it is difficult to achieve sufficient durability. If the ratio SW IN / SW OUTis greater than 0.9, the width of the band-shaped sound-absorbing element 10 on the vehicle interior and the width of the section on the vehicle exterior are substantially the same, and a sufficient effect by shifting the band-shaped sound-absorbing element 10 toward the vehicle exterior cannot be achieved. The ratios of the respective sections are preferably 0 < SW IN / CW < 2,2, 3 < SW OUT / CW < 7, and 0 < SW IN / SW OUT < 0.5.

[0023] Furthermore, as in Fig. 3, the cross-sectional area of ​​the portion of the band-shaped noise absorbing member 10 on the vehicle interior side SA OUT (the section hatched with a line in Fig. 3), the cross-sectional area of ​​the section on the vehicle interior side of the band-shaped noise absorbing member 10 is SA IN (the section hatched with two lines in Fig.3), the cross-sectional area of ​​the tire cavity formed between the tire and a rim is T (all in Fig. 3 sections drawn with a continuous line), and half of the cross-sectional area T is t (t = T / 2), and the ratio SA IN / t of the cross-sectional area SA IN and t is from 0 to 0.2 (0 ≤ SA IN / t ≤ 0.2), and the ratio SA OUT / t of SA OUT and t is from 0.1 to 0.4 (0.1 ≤ SA OUT / t ≤ 0.4). By setting the cross-sectional area of ​​each section of each element in this way within the appropriate range, in vehicles on which tires intended for high-speed travel are mounted with a negative camber, the heat build-up on the vehicle interior, where the build-up is likely to occur, is effectively reduced relatively easily, and the effect of improving high-speed durability by the middle cover layer 8c can be successfully demonstrated. When the ratio SA IN / t is greater than 0.2, the portion of the band-shaped sound absorbing member 10 on the vehicle interior cannot be sufficiently reduced, and the band-shaped sound absorbing member 10 located on the vehicle interior where heat buildup is likely to occur due to negative camber cannot be sufficiently reduced, whereby a sufficient effect of reducing heat buildup cannot be achieved. If the ratio SA OUT / t is greater than 0.1, the portion of the band-shaped sound absorbing member 10 on the vehicle exterior cannot be sufficiently increased, so that the portion of the band-shaped sound absorbing member 10 on the vehicle exterior cannot be sufficiently provided relative to the portion on the vehicle interior, and a sufficient effect by shifting the band-shaped sound absorbing member 10 to the vehicle exterior cannot be achieved. If the ratio SWOUT / t is larger than 0.4, the portion of the band-shaped sound absorbing member 10 on the vehicle outer side is too large, so that peeling is easy to occur from the end portions of the band-shaped sound absorbing member 10 on the vehicle outer side and it is difficult to obtain sufficient durability.

[0024] Furthermore, the ratio SA IN / SA OUT the cross-sectional area SA IN of the section of the band-shaped noise absorbing element 10 on the vehicle interior and the cross-sectional area SA OUT of the section of the band-shaped noise absorbing element 10 on the vehicle outer side is preferably less than 0.9 (SA IN / SA OUT < 0.9), and more preferably in the range of 0 to 0.7 (0 <SA IN / SA OUT < 0.5). Furthermore, the ratio SA / T of the total cross-sectional area of ​​the band-shaped noise-absorbing element is 10 SA (= SAIN + SA OUT ) and the cross-sectional area T of the tire cavity is preferably in the range of 0.05 to 0.4 (0.05 < SA / T < 0.4), and more preferably in the range of 0.1 to 0.3 (0.1 < SA / T < 0.3). By setting the cross-sectional area of ​​each portion in this way, a good balance is possible between the portion of the belt-shaped sound absorbing member 10 on the vehicle inside and the portion on the vehicle outside, which has the advantage that good low noise and high-speed durability can be provided in a compatible manner to a high degree. When the ratio SW IN / SW OUTis equal to or greater than 0.9, the cross-sectional area of ​​the portion of the band-shaped sound-absorbing member 10 on the vehicle interior and the cross-sectional area of ​​the portion on the vehicle exterior are substantially the same, and a sufficient effect cannot be achieved by shifting the band-shaped sound-absorbing member 10 toward the vehicle exterior. If the ratio SA / T is less than 0.05, the band-shaped sound-absorbing member is too small, making it difficult to achieve a sufficient sound-absorbing effect. If the ratio SA / T is greater than 0.4, the effect of reducing cavity resonance becomes constant, that is, the probability of further noise-reducing effect is not exhibited, and on the other hand, there is a problem of weight increase in the band-shaped sound-absorbing member 10.

[0025] The width and cross-sectional area of ​​the band-shaped sound absorbing member 10 are determined as described above, but, as shown in Fig.4, the shape is preferably such that there is a recessed portion 12 where the band-shaped sound absorbing member 10 is not present at least at one circumferential location. By providing the recessed portion 12 in this way, the expansion due to inflation of the tire and the shear strain due to rolling on the ground for long periods of time can be withstood. The recessed portion 12 is preferably provided at one location or at three to five locations on the tire circumference. In other words, if the recessed portion 12 is provided at two locations on the tire circumference, the uniformity of the tire will be significantly reduced due to unbalance, and in a case where it is provided at six or more circumferential locations, the manufacturing cost will be significantly increased. Examples

[0026] Sixteen different pneumatic tires with a tire size of 275 / 35ZR20 were produced, which cover the Fig. 1 to produce Prior Art Example 1, Comparative Examples 1 to 4 (not according to the invention), and Examples 1 to 11, wherein Example 5 is not according to the invention. The following ratios of the widths and cross-sectional areas of each element (belt layer, middle cover layer, and band-shaped sound-absorbing element) were set as shown in Table 1: Ratio SW / BW of the width SW of the band-shaped sound-absorbing element and the width BW of the belt layer; Ratio CW / SW of the width CW of the middle cover layer and the width SW of the band-shaped sound-absorbing element; Ratio SW IN / CW of width SW IN of the section of the band-shaped sound-absorbing element on the vehicle interior and the width of the middle cover layer 8c; ratio SWOUT / CW of the width of the section of the band-shaped sound-absorbing element on the vehicle outer side and the width of the middle cover layer 8c; ratio SW IN / SW OUT the width SW OUT of the section of the band-shaped noise-absorbing element on the vehicle exterior and the width SW IN of the section of the band-shaped sound-absorbing element and the vehicle interior; ratio SA IN / t of the cross-sectional area SA IN of the section of the band-shaped noise-absorbing element on the vehicle interior and half of the cross-sectional area T of the tire cavity (t); ratio SA OUT / t of the cross-sectional area SA OUT of the section of the band-shaped noise-absorbing element on the vehicle outer side and half of the cross-sectional area T of the tire cavity (t); ratio SA IN / SA OUT the cross-sectional area SA INof the section of the band-shaped noise-absorbing element on the vehicle interior and the cross-sectional area SA OUT of the section of the band-shaped sound-absorbing element on the vehicle exterior; and the ratio SA / T of the total cross-sectional area SA (=SA IN + SA OUT ) of the band-shaped noise absorbing element and the cross-sectional area T of the tire cavity.

[0027] It should be noted that in all examples, the width of the belt layer at the outermost side was 230 mm, and the thickness of the belt-shaped sound-absorbing member was 25 mm. Furthermore, in all examples including the middle belt layer, the middle belt layer was made of organic fiber cords interwoven with nylon fibers and aramid fibers. Prior Art Example 1 was an example that did not include the middle cover layer. Therefore, the value in the CW / SW column is 0, and the middle cover layer (width) column is blank.

[0028] High-speed durability, ride comfort, and low noise were evaluated for these 16 pneumatic tires according to the following evaluation methods, and the results thereof are also shown in Table 1. Durability at high speed

[0029] Each test tire was mounted on a 20x9.5J rim, and driving tests were conducted using a drum tester under conditions of air pressure of 270 kPa, load of 7.5 kN, and camber angle of -2°. Specifically, the initial speed was 250 km / h, and the speed was increased by 10 km / h every 20 minutes. The tire was driven until failure occurred. The speed at which failure occurred was measured. The evaluation results indicate the measured value (speed) for each test tire. Higher index values ​​indicate better high-speed durability. Driving comfort

[0030] Each test tire was mounted on a 20x9.5J rim, inflated to an air pressure of 230 kPa, and mounted on a test vehicle with a displacement of 3000 cc. A driving test was conducted by a test driver driving five laps on a 5-km test track, and ride comfort was evaluated using sensory evaluation. The evaluation results were evaluated in five stages, with the prior art example 1 being designated as "3." Higher values ​​indicate better ride comfort. Low noise

[0031] Each test tire was mounted on a 20x9.5J rim, inflated to an air pressure of 230 kPa, and mounted on a four-wheel drive test vehicle with a displacement of 3000 cc. The test vehicle was driven on a test track with an asphalt road surface at an average speed of 50 km / h. The sound pressure level of the noise was measured by a microphone mounted at the driver's side window, and the reciprocal readings were assigned to five levels, with the prior art example 1 being designated as "3." Higher index values ​​indicate better noise reduction. TABLE 1-II Example of the prior art 1 Example 1 Comparison example 1 Example 2 Example 3 SW / BW 0,7 0,7 0,2 0,3 0,5 CW / SW 0 0,2 0,2 0,2 0,2 SW IN / CW - 2,5 2,5 2,5 2,5 SW OUT / CW - 2,5 2,5 2,5 2,5 SW IN / SW OUT 1 1 1 1 1 on IN / t 0,2 0,2 0,2 0,2 0,2 on OUT / t 0,2 0,2 0,2 0,2 0,2 IN IN / IN OUT 1 1 1 1 1 SA / T 0,25 0,25 0,07 0,11 0,18 Durability at high km / h speed 310 330 340 330 330 Driving comfort 3 3 3 3 3 Low noise 3 3 2 3 3 TABLE 1-I-II Example 4 Comparison example 2 Comparison example 3 SW / BW 0,8 0,9 0,7 CW / SW 0,2 0,2 0,01 SW IN / CW 2,5 2,5 50 SW OUT / CW 2,5 2,5 50 SW IN / SW OUT 1 1 1 on IN / t 0,2 0,2 0,2 on OUT / t 0,2 0,2 0,2 IN IN / IN OUT 1 1 1 SA / T 0,29 0,32 0,25 Durability at high km / h speed 320 300 310 Driving comfort 3 3 3 Low noise 4 4 3 TABLE 1-II-I Example 5 Example 6 Example 7 Example 8 SW / BW 0,7 0,7 0,7 0,7 CW / SW 0,05 0,1 0,25 0,35 SW IN / CW 10 5 2 1,429 SW OUT / CW 10 5 2 1,429 SW IN / SW OUT 1 1 1 1 on IN / t 0,2 0,2 0,2 0,2 on OUT / t 0,2 0,2 0,2 0,2 IN IN / IN OUT 1 1 1 1 SA / T 0,25 0,25 0,25 0,25 Durability at high km / h speed 320 340 340 330 Driving comfort 3 3 3 3 Low noise 3 3 3 3 TABLE 1-II-II Comparison example 4 Example 9 Example 10 Example 11 SW / BW 0,7 0,7 0,7 0,7 CW / SW 0,8 0,2 0,2 0,2 SW IN / CW 0,625 2,4 1,9 0 SW OUT / CW 0,625 2,6 3,1 5 SW IN / SW OUT 1 0,9 0,6 0 on IN / t 0,2 0,12 0,1 0 on OUT / t 0,2 0,38 0,4 0,5 IN IN / IN OUT 1 0,9 0,6 0 SA / T 0,25 0,25 0,25 0,25 Durability at high km / h speed 330 340 350 350 Driving comfort 2 3 3 3 Low noise 2 3 3 3

[0032] As shown in Table 1, each of Examples 1 to 11 improved high-speed durability compared to Prior Art Example 1 while maintaining low noise and ride comfort. On the other hand, in Prior Art Example 1, the width of the band-shaped sound-absorbing member was too small, resulting in a deterioration in noise performance. In Comparative Example 2, the width of the band-shaped sound-absorbing member was too large, significantly increasing the heat buildup effect of the sound-absorbing member, and the middle cover layer was unable to sufficiently compensate for the high-speed durability, resulting in a deterioration in high-speed durability. In Comparative Example 3, the middle cover layer was too small, resulting in a failure to achieve an effect of improving high-speed durability.In comparative example 4, the middle surface layer was too large, so that in turn a detrimental effect on driving comfort and low noise was observed. List of reference symbols 1 tread section 2 side wall section 3 bead section 4 carcass layers 5 Bead core 6 bead fillers 7th belt layer 8 Belt cover layer 8f complete top layer 8c middle top layer 8th edge covering layer 10 band-shaped noise-absorbing element 11 Adhesive layer 12 Recessed section CL Tire Equator

Claims

[1] Pneumatic tire, comprising: an annular tread portion (1) extending in the tire circumferential direction; a pair of sidewall portions (2) arranged on both sides of the tread portion (1); a pair of bead portions (3) arranged inwardly of the sidewall portions (2) in the tire radial direction; a carcass portion disposed between a pair of tire bead portions (3); a plurality of belt layers (7) arranged on an outer periphery of the carcass layer (4) in the tread portion (1); a band-shaped noise absorbing member (10) attached to an inner surface of the tread portion (1) along the tire circumferential direction; at least one complete cover layer (8f) arranged on an outer peripheral side of the plurality of belt layers (7) and covering an entire width of the plurality of belt layers (7); and a middle cover layer (8c) arranged on an outer peripheral side of the complete cover layer (8f) and covering a central region of the plurality of belt layers (7) in the tire width direction in places; wherein the belt cover layers (8, 8c, 8f) each contain organic fiber cords oriented in an angular range of 0° to 5° inclusive to the tire circumferential direction; wherein a width SW of the band-shaped sound absorbing element (10) and a width BW of the plurality of belt layers (7) satisfy a ratio SW / BW = 0.3 to 0.8, wherein a width CW of the middle cover layer (8c) and the width SW of the band-shaped sound-absorbing element (10) satisfy a ratio CW / SW = 0.05 to 0.35, - wherein a mounting direction is given with respect to a vehicle; - wherein an outer side of a tire equator (CL) with respect to the vehicle is a vehicle outer side when the pneumatic tire is mounted on the vehicle, and wherein an inner side of the tire equator (CL) with respect to the vehicle is a vehicle inner side when the pneumatic tire is mounted on the vehicle; and - where a width SW OUT a section of the band-shaped noise-absorbing element (10) on the vehicle exterior, a width SW IN a section of the band-shaped noise-absorbing element (10) on the vehicle interior, and the width CW of the middle cover layers (8c) the ratios SW IN / CW < 5, SW OUT / CW < 8, and SW IN / SW OUT< 0.

9. [2] A pneumatic tire according to claim 1, wherein a mounting direction in relation to a vehicle is given; when the pneumatic tire is mounted on the vehicle, an outer side of a tire equator (CL) with respect to the vehicle is a vehicle outer side, and when the pneumatic tire is mounted on the vehicle, an inner side of the tire equator (CL) with respect to the vehicle is a vehicle inner side; and a cross-sectional area SA OUT a section of the band-shaped noise-absorbing element (10) on the vehicle interior, a cross-sectional area SA IN a portion of the band-shaped noise absorbing member (10) on the vehicle interior, and a cross-sectional area T of a tire cavity satisfy the relationships 0 ≤ SA IN / t ≤ 0.2 and 0.1 ≤ SA OUT / t ≤ 0.4 (t = T / 2). [3] A pneumatic tire according to any one of claims 1 to 2, wherein the middle cover layer (8c) is made of organic fiber cords in which nylon fibers and aramid fibers are interwoven. [4] A pneumatic tire according to any one of claims 1 to 3, wherein the band-shaped noise absorbing member (10) comprises a recessed portion (12) at least at a portion in the tire circumferential direction.

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