JP2010143348A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire reducing road noise on the basis of adoption of a carcass including a pair of side plies separately disposed in right and left, inner and outer center plies embracing an outer end of each side ply from inside and outside in the tire radial direction, and high damping rubber disposed between cords of the side plies and the center plies. <P>SOLUTION: The carcass 6 includes a first side ply 6a extending from an outer end E1 in a tread section 2 to a bead section 4 through one side wall section 3a, a second side ply 6b extending from an outer end E2 positioned separating from the outer end E1 of the first side ply 6a to the other side wall section 3b side to the bead section through the other side wall section 3b, the inner center ply 6c extending in the axial direction in the tread section 2 with both ends respectively extending inside of outer end sections 6ae, 6be that include respective outer ends E1, E2 of the first and the second side plies 6a, 6b, and the outer center ply 6d disposed outside the inner center ply 6c with both ends respectively extending outside the outer end sections 6ae, 6be of the first and the second side plies 6a, 6b. The high damping rubber 9 with 0.4 or higher tanδ is disposed between the cords of the center plies 6c, 6d and the cords of the side plies 6a, 6b in the outer end sections 6ae, 6be. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire that can reduce road noise.

  With the recent quietness of vehicles, reduction of noise generated by tires is also desired. Generally, a passenger car has a resonance frequency around 125 Hz. In order to prevent the vibration generated in the tire from being transmitted to the passenger compartment sensitively, it is effective to improve the structure of the tire and lower the vibration level in the vicinity of 125 Hz.

  In the following Patent Document 1, in order to exhibit excellent handling performance and uniform wear characteristics, the carcass ply on the vehicle outer side and the carcass ply on the vehicle inner side are arranged to overlap each other in the tread portion. A pneumatic tire having a carcass is disclosed.

Further, in Patent Document 2 below, in order to improve the ride comfort, a tread rubber composed of an outer rubber layer and an inner rubber layer in the tire radial direction is provided, and the loss tangent tan δ is 0.40 or more in the outer rubber layer. A pneumatic radial tire using a rubber composition is described.
JP 2000-343908 A JP-A-1-160705

  The present invention includes a pair of side plies arranged separately on the left and right sides, an inner center ply between the inner and outer sides of the outer side of the tire in the tire radial direction, and a side ply and a center ply. The main object is to provide a pneumatic tire capable of reducing road noise on the basis of employing a carcass including a high damping rubber disposed between cords.

  The present invention is a pneumatic tire having a carcass extending in a toroidal shape between a pair of bead parts, and a belt layer disposed on the outer side in the tire radial direction of the carcass and on the inner side of the tread part. Is a first side ply composed of a cord array body folded from the outer end in the tire radial direction located in the tread portion through one sidewall portion by a bead core of the bead portion, and the first side of the tread portion A cord array that is folded at the bead core of the bead portion from the outer end in the tire radial direction provided at a position spaced from the outer end of the portion ply to the other sidewall portion side. The two side plies and the tread portion extend in the tire axial direction, and both ends include the outer ends of the first side ply and the second side ply, respectively. An inner central ply formed of a cord array extending inward in the tire radial direction of the end portion, an outer side of the inner central ply in the tire radial direction extending in the tire axial direction, and both ends thereof are the first side ply and the first side ply, respectively. An outer central ply comprising a cord array extending outward in the tire radial direction of the outer end portion of the two side plies, and a cord between the central ply and the side ply cord facing in the tire radial direction at the outer end portion And a high attenuation rubber having a loss tangent tan δ of 0.4 or more.

  The belt layer is formed by overlapping two belt plies made of steel cords inclined at an angle of 10 to 40 ° with respect to the tire equator in a direction in which the steel cords cross each other, and each side portion It is preferable that both ends of the outer end of the ply, the inner central ply, and the outer central ply are provided in an inner region in the tire radial direction of the belt layer.

  The cords of the side plies are inclined at an angle θ2 of 65 to 90 ° with respect to the tire circumferential direction, and the cords of the inner and outer central plies are at the angle θ2 with respect to the tire equator. It is desirable that the cords are inclined at a smaller angle θ3 and arranged in directions in which the cords cross each other.

  Further, the high damping rubber is arranged between the cords of the side plies and the cord of the inner central ply, and between the cords of the side plies and the cord of the outer central ply, respectively. desirable.

  The overlapping length of the side ply cord and the central ply cord in the tire axial direction is 5 to 30% of the maximum width of the belt layer, and the high damping rubber has a thickness of 2 mm or more. It is desirable to have.

  The cords of the side ply and the central ply are preferably organic fiber cords.

  In the pneumatic tire of the present invention, the vibration level near 125 Hz is reduced by improving the carcass structure. Therefore, road noise during vehicle travel is reduced. Moreover, when the angle of the cords of the side ply and the central ply is regulated as in the invention described in claim 3, the vibration level in the vicinity of 315 Hz can be reduced while preventing the deterioration of riding comfort, and road noise is further reduced. Reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional view of a normal state of the pneumatic tire 1 of the present embodiment, and FIG. 2 shows a development view of the internal structure of the tread portion 2 thereof. Here, the normal state is a state in which the tire is assembled to a normal rim (not shown) and filled with a normal internal pressure and is in a no-load state. Specified by state.

  The “regular rim” is a rim determined by each standard for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA and “Design Rim” for TRA. "If ETRTO," Measuring Rim ".

  Further, the “regular internal pressure” is the air pressure defined by each standard for each tire in the standard system including the standard on which the tire is based. The maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” is “INFLATION PRESSURE” if it is ETRTO.

  A pneumatic tire 1 according to this embodiment includes a tread portion 2, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends thereof, and bead cores 5 provided at inner ends of the sidewall portions 3. Is shown for a passenger car having a bead portion 4 embedded therein. The pneumatic tire 1 includes a carcass 6 extending between the pair of bead portions 4 and 4 in a toroidal shape, and a belt layer 7 disposed on the outer side in the tire radial direction of the carcass 6 and on the inner side of the tread portion 2. Have

  As shown in FIGS. 1 and 2, the belt layer 7 of this embodiment is composed of two belt plies 7 </ b> A and 7 </ b> B that overlap each other in the tire radial direction. Each belt ply 7A, 7B is arranged with a plurality of steel cords 7s inclined at an angle θ1 of 10 to 40 ° with respect to the tire equator C, for example. The two belt plies 7A and 7B are overlapped with each other so that the center lines of the respective widths are aligned and the steel cords 7s intersect each other.

  The belt ply 7A on the inner side in the tire radial direction has a larger width than the outer belt ply 7B. Therefore, the edge of the inner belt ply coincides with the outer ends 7e, 7e of the belt layer 7, and the distance in the tire axial direction between the outer ends 7e, 7e is defined as the maximum width BW of the belt layer 7. In order to ensure the rigidity of the tread portion 2 to improve wear resistance and to exert a large cornering force during turning, the maximum width BW of the belt layer 7 is desirably, for example, 85 to 110% of the tread ground contact width TW.

  The tread ground contact width TW is a tire between the grounding ends 2e and 2e that is grounded on the outermost side of the tread portion 2 when a normal load is applied to a tire in a normal state and is grounded on a flat surface with a camber angle of 0 °. Defined as the axial distance.

  The “regular load” is a load determined by each standard for each tire in a standard system including the standard on which the tire is based. “JATMA” is “maximum load capacity”, and TRA is a table. The maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” in the case of ETRTO. However, when the tire is for a passenger car, the load is equivalent to 88% of each load.

  The carcass 6 includes a first side ply 6a, a second side ply 6b, an inner central ply 6c, and an outer central ply 6d.

  The first side ply 6a is folded from the inner side to the outer side by the bead core 5 of the inner bead part 4 from the outer end E1 in the tire radial direction located in the tread part 2 through one side wall part 3a. And an array of code 6A.

  The outer end E1 of the first side ply 6a is in the inner area in the tire radial direction of the belt layer 7, and is preferably provided in the vicinity of one outer end 7e of the belt layer 7. Therefore, the first side ply 6a and the belt layer 7 overlap each other with a predetermined length S in the tire axial direction. In addition, the first side ply 6a has the other end E3 that is folded back at the bead core 5 and then is cut off at a position beyond the bead apex rubber 8 that extends from the bead core 5 outward in the tire radial direction. In the present embodiment, the other end E3 is provided at a position not exceeding the outer end E1.

  The second side ply 6b has a tire radial outer end E2 of the tread portion 2 provided at a position spaced from the outer end E1 of the first side ply 6a toward the other sidewall portion 3b. And an array of cords 6B that are folded back by the bead core 5 of the inner bead portion 4 through the other side wall portion 3b. Therefore, the second side ply 6b is arranged separately from the first side ply 6a without overlapping.

  The outer end E2 of the second side ply 6b is in the inner area in the tire radial direction of the belt layer 7, and is preferably provided in the vicinity of the other outer end 7e of the belt layer 7. Therefore, the second side ply 6b and the belt layer 7 overlap each other with a predetermined length S in the tire axial direction. Further, the second side ply 6b also has the other end E3 that is folded back by the bead core 5 and ends at a position beyond the bead apex rubber 8 (a position not exceeding the outer end E2).

  In the present embodiment, in the tire meridian cross section shown in FIG. 1, the outer end E2 and the other end E3 of the second side ply 6b are related to the tire equator C, respectively, and the outer end E1 of the first side ply 6a and It is provided at a position substantially symmetrical with the other end E3.

  The inner central ply 6c extends outside the tread portion 2 in the tire axial direction, and both end portions include outer ends E1 and E2 of the first side ply 6a and the second side ply 6b, respectively. It consists of an array of cords 6C extending inward in the tire radial direction of 6ae and 6be. That is, both ends 6ce of the inner central ply 6c are located at positions beyond the outer end E1 of the first side ply 6a and the outer end E2 of the second side ply 6b outward in the tire axial direction. As a result, the inner central ply 6c overlaps the outer end portions 6ae and 6be, respectively. In the present embodiment, both ends 6ce and 6ce of the inner central ply 6c are provided at symmetrical positions with respect to the tire equator C.

  The outer central ply 6d is disposed on the outer side in the tire radial direction of the inner central ply 6c, extends in the tire axial direction of the tread portion 2, and both end portions thereof are the first side ply 6a and the second side ply, respectively. The outer end portions 6ae and 6be of the ply 6b are composed of an array of cords 6D extending outward in the tire radial direction. That is, both ends 6de of the outer central ply 6d are also in positions beyond the outer end E1 of the first side ply 6a and the outer end E2 of the second side ply 6b to the outside in the tire axial direction. As a result, the outer central ply 6d also overlaps the outer end portions 6ae and 6be. In the present embodiment, both ends 6de and 6de of the outer central ply 6c are also provided at symmetrical positions with respect to the tire equator C.

  As described above, the carcass 6 of the present embodiment has a pair of side plies 6a and 6b arranged separately on the right and left sides, and outer end portions 6ae and 6be of the side plies 6a and 6b from the inside and outside of the tire radial direction. A toroidal shape is formed by including the outer central plies 6c and 6d having both ends sandwiched therebetween. Such a carcass 6 effectively increases the rigidity of both end portions of the belt layer 7, particularly the torsional rigidity, because the cords overlap in three layers at the outer end portions 6 ae and 6 be of the side plies 6 a and 6 b. it can. And it has been confirmed by the inventors' experiments that such a pneumatic tire 1 effectively reduces the vibration level in the frequency band near 125 Hz.

  Further, the carcass 6 of the present embodiment is provided between the cord 6C or 6D of the central ply and the cord 6A or 6B of the side ply facing each other in the tire radial direction at the outer end portions 6ae and 6be of the side plies 6a and 6b. A high-damping rubber 9 having a loss tangent tan δ of 0.40 or more is disposed on at least a part thereof.

The regions where the high-damping rubber 9 can be disposed are the following regions A1 to A4 as schematically shown in FIG.
A1: Between the cord 6A of the first side ply 6a and the cord 6C of the inner central ply 6c A2: Between the cord 6A of the first side ply 6a and the cord 6D of the outer central ply 6d A3: Between the cord 6B of the second side ply 6b and the cord 6C of the inner central ply 6c A4: Between the cord 6B of the second side ply 6b and the cord 6D of the outer central ply 6d In the entering tire 1, the high-damping rubber 9 may be disposed in at least one region of the regions A1 to A4. In the present embodiment, the high-damping rubber 9 is disposed in all four areas. Moreover, in each area | region A1 thru | or A4, the high attenuation | damping rubber | gum 9 has extended continuously in the tire circumferential direction.

  Thus, the high-damping rubber 9 having a large tan δ can attenuate vibrations by converting more vibration energy into heat energy. Therefore, most of the vibration input to the tread portion 2 during traveling is efficiently converted into heat by shear deformation of the high damping rubber 9 when it is transmitted from the central plies 6c, 6d to the side plies 6a, 6b. Attenuated. This helps to reduce the overall vibration level of the pneumatic tire 1.

  Here, with a rubber having a loss tangent tan δ less than 0.4, vibration cannot be reliably reduced. In a particularly preferred embodiment, a rubber composition having a loss tangent tan δ of 0.5 or more is employed for the high damping rubber 9. On the other hand, if the loss tangent tan δ of the high-damping rubber 9 is excessively large, heat generation at the tread portion 2 is increased, which may reduce durability, and is preferably 0.8 or less, more preferably 0.7 or less. Is desirable.

  The loss tangent tan δ of the high-damping rubber 9 is a value measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho according to JIS-K6394 and the following conditions.

Initial strain: 10%
Amplitude: ± 1%
Frequency: 10Hz
Deformation mode: Tensile Measurement temperature: 70 ° C
The high damping rubber 9 is only required to be disposed between the cords of the central ply and the side plies facing each other in the outer end portions 6ae and 6be. Therefore, in this embodiment, the high damping rubber 9 is not disposed in the region other than the above.

  The high damping rubber 9 is preferably arranged symmetrically with respect to the tire equator C. That is, the aspect arrange | positioned to area | region A1 and area | region A3, or the aspect distribute | arranged to area | region A2 and area | region A4 is desirable. In the most preferable aspect, the high damping rubber 9 is disposed in all the regions A1 to A4 as in the present embodiment.

  As shown in FIG. 2 or FIG. 4, the high damping rubber 9 of the present embodiment is a rubber sheet that is disposed between the plies in the carcass molding process. That is, as shown in an enlarged view in FIG. 4, the side ply 6b and the central plies 6c, 6d are both covered with a topping rubber 6t, and a sheet-like high height is provided between the topping rubbers 6t, 6t. A damping rubber 9 is arranged.

  Further, as shown in FIG. 5, the high damping rubber 9 forms part of the topping rubber 6t that covers the cords of the side plies 6a and 6b or the central plies 6c and 6d. Thru | or A4 may be arrange | positioned. For example, in the embodiment of FIG. 5, only a part of the topping rubber 6t of the side ply 6b, more specifically, only the topping rubber 6t of the outer end portion 6be is formed of the high damping rubber 9, and the side ply 6b The other part of the topping rubber 6t is formed of a normal rubber 11 having a loss tangent tan δ of less than 0.40. The high damping rubber 9 may be used as a topping rubber that covers the cords at both ends of the central ply, for example.

  Further, in each of the areas A1 to A4, the maximum thickness t of the high-damping rubber 9 is not particularly limited, but if it is too small, the vibration absorption effect may be lowered. Preferably it is 2 mm or more. On the other hand, if the maximum thickness t of the high-damping rubber 9 becomes excessively large, the energy loss increases and there is a risk of causing deterioration of rolling resistance and excessive internal heat generation. From such a viewpoint, the thickness t of the high damping rubber 9 is preferably 5 mm or less, more preferably 4 mm or less.

  Further, the overlap length L in the tire axial direction between the cord 6A or 6B of the side ply and the cord 6C or 6D of the center ply is not particularly limited, but if the length L becomes small, the belt layer There is a possibility that it is difficult to sufficiently increase the rigidity of both ends of the belt 7, and there is a possibility that the road noise cannot be sufficiently reduced. On the contrary, when the overlap length L is excessively large, the rigidity of the tread portion 2 is excessively increased, and the ride comfort may be remarkably deteriorated. From such a viewpoint, the overlapping length L between the inner and outer central plies 6c and 6d and the side plies 6a and 6b is 5% or more of the maximum width BW of the belt layer 7, more preferably 10%. The above is desirable, and preferably 30% or less, more preferably 20% or less.

  The overlap length L is preferably determined symmetrically with respect to the tire equator C. The inner central ply 6c and the outer central ply 6d are preferably overlapped with the side plies with the same overlap length L.

  The width of the high-damping rubber 9 in the tire axial direction is preferably 50% or more, more preferably 60% or more, and still more preferably substantially 100% of the overlap length L. If the width of the high-damping rubber 9 in the tire axial direction is less than 50% of the overlap length L, the vibration absorption effect may be reduced.

  Further, the overlapping length S of the side plies 6a, 6b and the belt layer 7 in the tire axial direction is not particularly limited, but if the length S is too small, the tension acting on the internal pressure filling or the like may occur. The side plies 6a and 6b may be displaced from the central plies 6c and 6d. From such a viewpoint, the overlap length S is desirably 5% or more of the maximum width BW of the belt layer 7, more preferably 15% or more. The upper limit of the overlap length S can be determined in the same manner as the overlap length L described above, and is preferably determined symmetrically with respect to the tire equator C.

  Further, a band layer 10 (shown by a broken line in FIG. 1) that covers at least the outer side in the tire radial direction of the belt layer 7 within the range of the overlapping length S may be further provided. The band layer 10 is formed of a band ply in which organic fiber cords are arranged at an angle of 5 ° or less in the tire circumferential direction, and both end portions of the belt layer 7 can be more effectively reinforced and the torsional rigidity can be further increased. As the organic fiber cord, not only a relatively low elastic material such as nylon or rayon but also a high elastic organic fiber cord such as aramid or polyethylene naphthalate can be adopted.

  Further, the carcass 6 of the present embodiment is configured in a toroidal shape by partially overlapping the side plies 6a and 6b and the central plies 6c and 6d. Accordingly, at least one parameter of the cord angle of the ply, the cord material, and / or the number of cords to be driven can be made different from those of the other plies. More preferably, different cord angles, cord materials, and / or cord driving numbers can be employed for the side plies 6a and 6b and the central plies 6c and 6d.

  As shown in FIG. 2, for example, the cords 6A and 6C of the side plies 6a and 6b are preferably inclined at an angle θ2 of 65 to 90 °, more preferably 80 to 90 ° with respect to the tire circumferential direction. . That is, since the side wall portion 3 includes the cords 6A and 6B extending substantially along the radial direction, as in the case of the conventional radial tire, the flexible side portion bendability can be secured and the shock absorption and the riding comfort can be maintained. .

  On the other hand, the cords 6C and 6D of the inner and outer central plies 6c and 6d are preferably inclined with respect to the tire equator C at an angle θ3 smaller than the angle θ2, more preferably 35 to 45 °. . At this time, the cord 6C of the inner central ply 6c and the cord 6D of the outer central ply 6d are arranged so as to cross each other. The central plies 6c and 6d are formed into a so-called low angle in which the cords 6C and 6D approach the tire circumferential direction, so that the rigidity of the tread portion 2 can be further enhanced by a synergistic action with the belt layer 7.

  As in this embodiment, the pneumatic tire in which the tread portion 2 is reinforced by the belt layer and the low-angle cord ply does not impair the ride comfort, and the secondary frequency (about approximately) of the tire cross section. 315 Hz) band noise level can be effectively reduced. Therefore, road noise during vehicle travel can be further reduced.

  Further, the cord angle θ3 of the central plies 6c and 6d is preferably smaller than the angle θ2 but larger than the cord angle θ1 of the belt plies 7A and 7B. Thereby, it is difficult to transmit the vibration from the tread portion 2 inward in the tire radial direction, and as a result, an effect of reducing the vibration level and improving the riding comfort level can be expected. At this time, the cord angle difference (θ3−θ1) is preferably not less than 10 °, more preferably not less than 15 °, and preferably not more than 40 °, in order to exhibit the above action more reliably. Preferably it is 30 ° or less.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above, and can be implemented with various modifications.

  In order to confirm the effects of the present invention, pneumatic tires for passenger cars were prototyped, and various performances were tested for them. The pneumatic tires of the examples all have the basic configuration shown in FIGS. Further, the width in the tire axial direction of the high damping rubber was arranged so as to satisfy substantially the entire region (100%) of the overlapping length of the side ply and the central ply.

  For comparison, as a comparative example 1, a pneumatic tire including a carcass composed of one carcass ply continuous from one bead portion to the other bead portion is shown as a comparative example 2 in FIG. Each pneumatic tire having a basic configuration but no high damping rubber was tested. The parameters other than those shown in Table 1 were substantially the same. The main common specifications are as follows.

Tire size: 195 / 65R15
Maximum width of belt layer BW: 160mm
Belt cord material: Steel cord Carcass cord material: Polyester The test method is as follows.
<Road noise>
Each sample tire is fitted to all wheels of a 2000cc domestic FF passenger car with a 6JJ rim and 230kPa air pressure, running smoothly on the road surface at a speed of 50km / h, and 1/3 at the driver's seat left ear position The noise levels (dB) at 80 Hz, 125 Hz and 315 Hz of the octave band analysis were measured, respectively. The results are shown as the sum of the reduction allowances for each channel based on Comparative Example 1. It is preferable that the numerical value is negative.
<Ride comfort>
Using a test vehicle similar to the above, a driver's sensory evaluation was performed on the stepped road on the dry asphalt road surface, the Belgian road, the Bitzmann road, etc. with respect to the rugged feeling, push-up, and damping, and the comparative example 1 was displayed with a score of 100. Yes. The larger the value, the better.
<Rolling resistance>
Using a rolling resistance tester, each tire was mounted on a 6JJ rim, and the rolling resistance was measured at an air pressure of 230 kPa, a speed of 50 km / h, and a load of 4 kN, and displayed as an index when the tire of Comparative Example 1 was taken as 100. The smaller the value, the better.

  The results of the test are shown in Table 1.

テストの結果、実施例の空気入りタイヤは、乗り心地や転がり抵抗を悪化させることなく、ロードノイズを低減させていることが確認できた。

As a result of the test, it was confirmed that the pneumatic tire of the example reduced road noise without deteriorating riding comfort and rolling resistance.

It is sectional drawing of the pneumatic tire which shows embodiment of this invention. It is an expanded view inside the tread part. It is a partial schematic diagram of the carcass of this embodiment. It is the elements on larger scale of the tread part of the pneumatic tire of this embodiment. It is the elements on larger scale of the tread part of the pneumatic tire of other embodiments.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 6a First side ply 6b Second side ply 6c Central ply 6d Outside central ply 7 Belt layer 9 High damping rubber

Claims (6)

A pneumatic tire having a carcass extending in a toroidal shape between a pair of bead parts, and a belt layer disposed on the outer side in the tire radial direction of the carcass and inward of the tread part, wherein the carcass is
A first side ply consisting of a cord array body folded at the bead core of the bead portion from the outer end in the tire radial direction located in the tread portion through one sidewall portion;
Folded at the bead core of the bead portion from the outer end in the tire radial direction provided at a position spaced from the outer end of the first side ply of the tread portion to the other sidewall portion side through the other sidewall portion. A second side ply consisting of a coded coding array;
An inner portion of a cord array that extends in the tire radial direction and has both end portions extending radially inward of the outer end portion including the outer ends of the first side ply and the second side ply, respectively. Central ply,
A cord array in which the outer side in the tire radial direction of the inner central ply extends in the tire axial direction, and both end portions extend in the tire radial direction outside of the outer end portions of the first side ply and the second side ply, respectively. An outer central ply consisting of: and at least part of the outer end portion between the cord of the central ply and the cord of the side ply facing in the tire radial direction, and the loss tangent tan δ is 0.4 or more A pneumatic tire characterized by containing high-damping rubber. The belt layer is formed by overlapping two belt plies made of steel cords inclined at an angle of 10 to 40 ° with respect to the tire equator in a direction in which the steel cords cross each other, and the side portions 2. The pneumatic tire according to claim 1, wherein both ends of the outer end of the ply, the inner central ply, and the outer central ply are provided in an inner region in the tire radial direction of the belt layer. The side ply cord is inclined at an angle θ2 of 65 to 90 ° with respect to the tire circumferential direction, and
The pneumatic tire according to claim 1 or 2, wherein the cords of the inner and outer central plies are inclined at an angle θ3 smaller than the angle θ2 with respect to the tire equator and are arranged in directions in which the cords intersect each other.   The high-damping rubber is disposed between a cord of each side ply and a cord of an inner central ply, and between a cord of each side ply and a cord of an outer central ply, respectively. 4. The pneumatic tire according to any one of 3. The overlapping length of the side ply cord and the central ply cord in the tire axial direction is 5 to 30% of the maximum width of the belt layer, and the high damping rubber has a thickness of 2 mm or more. Item 5. The pneumatic tire according to any one of Items 1 to 4.
  The pneumatic tire according to any one of claims 1 to 5, wherein the cords of the side ply and the central ply are organic fiber cords.

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