JP2006327321A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of simultaneously enhancing high speed durability and driving stability. <P>SOLUTION: A belt layer 20 comprises: a reinforcement layer 21 including a 0-degree internal cord 22 arranged horizontal to the tire circumferential direction; a 90-degree reinforcement layer 24 including a cord 25 arranged perpendicular to the tire circumferential direction; and an external reinforcement layer 27 having a 0-degree external cord 28 arranged horizontal to the tire circumferential direction, and arranged in this order from the inside toward the outside in the tire radial direction. This can enhance tensile rigidity in the tire circumferential direction for the high durability and in-plane bending rigidity for the reinforcement layer 24, to enhance the high speed durability and operational stability simultaneously. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire. In particular, the present invention relates to a pneumatic tire having a plurality of belt layers.

  Conventional pneumatic tires are required to improve safety when the vehicle travels as the performance of the vehicle increases, and some of them are designed to improve braking performance and steering stability accordingly. For example, in Patent Document 1, two carcasses are provided so as to overlap each other, and further, the cords of both carcasses cross each other while inclining within a range of 74 to 84 degrees with respect to the tire circumferential direction. Provided. Further, the cords of the belt layer located on the outer side in the tire radial direction than the carcass are formed so as to be substantially parallel to the tire circumferential direction. As a result, the two carcasses are constrained to each other, and further, the braking performance and the handling stability are improved by the tagging effect of the belt layer in which the cord parallel to the tire circumferential direction is formed.

JP 2004-155379 A

  However, in the pneumatic tire described above, the cord of the belt layer is formed so as to be substantially parallel to the tire circumferential direction. Therefore, when the load acting on the pneumatic tire is mainly in the tire circumferential direction, braking is performed. However, when a load is applied also in the tire width direction such as cornering, there is a possibility that the rigidity cannot be secured. In this case, there is a possibility that the steering stability is difficult to improve due to insufficient rigidity. In recent years, the performance of high-speed traveling has been remarkably improved, and it has been necessary to further improve the performance during high-speed traveling, such as the durability during high-speed traveling even for pneumatic tires.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can improve both high-speed durability and steering stability.

  In order to solve the above-described problems and achieve the object, the pneumatic tire according to the present invention is provided with at least one pneumatic tire outward in the tire radial direction from the carcass and substantially in the tire circumferential direction. An inner 0 degree reinforcing layer having an inner 0 degree cord formed at an angle of 0 degree, and at least one piece on the outer side in the tire radial direction of the inner 0 degree reinforcing layer, and with respect to the tire circumferential direction A 90-degree reinforcing layer having a 90-degree cord formed at an angle of substantially 90 degrees, the 90-degree cord being held by an elastic member, and at least one on the radially outer side of the 90-degree reinforcing layer in the tire radial direction. And an outer 0-degree reinforcing layer having an outer 0-degree cord formed at an angle of substantially 0 degrees with respect to the tire circumferential direction.

  In the present invention, the 90-degree reinforcing layer is sandwiched between the inner 0-degree reinforcing layer and the outer 0-degree reinforcing layer. Among these, the inner 0 degree reinforcing layer and the outer 0 degree reinforcing layer have an inner 0 degree cord or an outer 0 degree cord which is a cord formed at an angle of substantially 0 degrees in the tire circumferential direction. The tensile rigidity in the tire circumferential direction is high. As a result, even when a large tensile load acts in the tire circumferential direction, such as during high-speed driving, the load can be received by the inner 0 degree reinforcing layer and the outer 0 degree reinforcing layer. Is hard to break. In addition, since the 90-degree reinforcing layer is sandwiched between the inner 0-degree reinforcing layer and the outer 0-degree reinforcing layer, the compression rigidity of the elastic member that is a rubber or elastomer located between the cords of the 90-degree cord included in the 90-degree reinforcing layer. And in-plane bending rigidity can be ensured. As a result, when a load acts simultaneously in the tire circumferential direction and the tire width direction, such as during cornering, the load can be received by the in-plane bending rigidity of the 90-degree reinforcing layer, thereby improving steering stability. it can. As a result, both high speed durability and steering stability can be improved.

  In the pneumatic tire according to the present invention, at least one of the inner 0 degree cord and the outer 0 degree cord is composed of a composite cord in which a low elastic fiber and a high elastic fiber are combined. .

  In the present invention, at least one of the inner 0 degree cord and the outer 0 degree cord is formed by the composite cord in which the low elastic fiber and the high elastic fiber are combined, so that the lift is followed when the pneumatic tire is molded. be able to. Further, by using the composite cord, the tensile rigidity in the tire circumferential direction of the inner 0 degree reinforcing layer or the outer 0 degree reinforcing layer is improved, and the performance against tensile fatigue is improved. As a result, the tensile load in the tire circumferential direction during high-speed traveling can be more reliably received. As a result, high-speed durability can be further improved, and a pneumatic tire that can improve both high-speed durability and steering stability can be easily manufactured.

  In the pneumatic tire according to the present invention, the 90-degree cord is a steel cord.

  In the present invention, since the 90-degree cord is formed of a steel cord, the compression rigidity of the elastic member that holds the 90-degree cord can be used more reliably. As a result, the steering stability can be improved more reliably.

  In the pneumatic tire according to the present invention, the 90-degree reinforcing layer has an end portion in the tire width direction that is folded back outward in the tire radial direction or inward in the tire radial direction. .

  In this invention, since the end portion of the 90-degree reinforcing layer is folded, the folded portions can be overlapped to further improve the rigidity of the portion. Further, since the end portion is folded back, the edge of the end portion of the 90-degree reinforcing layer is eliminated, so that damage such as occurrence of separation starting from the edge portion of the reinforcing layer can be suppressed. As a result, the steering stability can be further improved and the durability can be improved.

  The pneumatic tire according to the present invention is characterized in that the width of the 90-degree reinforcing layer in the tire width direction is narrower than the width of the inner 0-degree reinforcing layer and the outer 0-degree reinforcing layer in the tire width direction. To do.

  In this invention, since the width in the tire width direction of the 90 degree reinforcing layer is narrower than the width in the tire width direction of the inner 0 degree reinforcing layer and the outer 0 degree reinforcing layer, the entire 90 degree reinforcing layer is reinforced at the inner 0 degree. It can be sandwiched between the layer and the outer 0 degree reinforcing layer. Thereby, the compressive rigidity of the 90-degree reinforcing layer can be used more reliably, and a load acting during cornering can be more reliably received by the in-plane bending rigidity of the 90-degree reinforcing layer. As a result, the steering stability can be improved more reliably.

  The pneumatic tire according to the present invention has an effect that both high-speed durability and steering stability can be improved.

  Hereinafter, an embodiment of a pneumatic tire according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

(Embodiment)
In the following description, the tire width direction refers to a direction parallel to the rotation axis of the pneumatic tire, the inner side in the tire width direction refers to the direction toward the equator in the tire width direction, and the outer side in the tire width direction refers to the tire. The direction opposite to the direction toward the equatorial plane in the width direction. Further, the tire radial direction refers to a direction orthogonal to the rotation axis, and the tire circumferential direction refers to a direction rotating around the rotation axis as a center of rotation. FIG. 1 is a meridional cross-sectional view showing a main part of a pneumatic tire according to the present invention. The pneumatic tire 1 shown in the figure has a tread portion 5 provided at the outermost portion in the tire radial direction when viewed in a meridional section. Further, a sidewall portion 7 is provided from the end portion of the tread portion 5 in the tire width direction, that is, from the vicinity of the shoulder portion 8 to a predetermined position on the inner side in the tire radial direction. A bead portion 16 is provided on the inner side in the tire radial direction of the portion 7. The bead portions 16 are provided at two locations of the pneumatic tire 1 and are also provided on the opposite side of the equator plane 3 so as to be symmetrical about the equator plane 3. A bead core 17 is provided on the bead portion 16, and a bead filler 18 is provided on the outer side of the bead core 17 in the tire radial direction.

  A plurality of belt layers 20 are provided on the inner side of the tread portion 5 in the tire radial direction. A carcass 10 is continuously provided on the inner side in the tire radial direction of the belt layer 20 and on the equatorial plane 3 side of the sidewall portion 7. The carcass 10 is folded back outward in the tire width direction along the bead core 17 at the bead portion 16. An inner liner 15 is formed along the carcass 10 on the inner side of the carcass 10 or on the inner side of the carcass 10 in the pneumatic tire 1.

  Among the plurality of belt layers 20, the belt layer 20 that is located closest to the inner side in the tire radial direction and is adjacent to the carcass 10 on the outer side in the tire radial direction of the carcass 10 is an inner 0-degree reinforcing layer 21. . Of the plurality of belt layers 20, the belt layer 20 provided adjacent to the inner 0 degree reinforcing layer 21 and outside the inner 0 degree reinforcing layer 21 in the tire radial direction is a 90 degree reinforcing layer 24. Among the plurality of belt layers 20, the belt layer 20 provided adjacent to the 90-degree reinforcement layer 24 and outside the 90-degree reinforcement layer 24 in the tire radial direction is an outer 0-degree reinforcement layer 27. Of these belt layers 20, the width in the tire width direction of the 90-degree reinforcing layer 24 is narrower than the width in the tire width direction of both the inner 0-degree reinforcing layer 21 and the outer 0-degree reinforcing layer 27. The width of the inner 0 degree reinforcing layer 21 in the tire width direction is narrower than the width of the outer 0 degree reinforcing layer 27 in the tire width direction.

  FIG. 2 is a cross-sectional view taken along the line AA of FIG. Each belt layer 20 has a cord that forms the belt layer 20. Among these, the cord that the inner 0 degree reinforcement layer 21 has is the inner 0 degree cord 22, and the cord that the outer 0 degree reinforcement layer 27 has is the outer 0 degree cord 28. Both the inner 0 degree cord 22 and the outer 0 degree cord 28 are formed at an angle of substantially 0 degree with respect to the tire circumferential direction, and the cords formed at this angle are arranged in the tire width direction. It is wound in a spiral. Further, the 90-degree cord 25 that is the cord included in the 90-degree reinforcing layer 24 is formed to be inclined in the tire width direction at an angle of substantially 90 degrees with respect to the tire circumferential direction. 90 ° cords 25 are arranged in the tire circumferential direction. Further, the plurality of 90 degree cords 25 arranged in the tire circumferential direction are held by a rubber 26 that is an elastic member. The rubber 26 covers the 90 degree cord 25 and is located between adjacent 90 degree cords 25. positioned. In addition, as long as it has elasticity and can hold | maintain the 90 degree | times code | cord 25, you may use things other than rubber | gum 26, such as an elastomer, for example.

  The inner 0 degree cord 22 and the outer 0 degree cord 28 do not have to be formed at an angle of exactly 0 degrees with respect to the tire circumferential direction, and are within a range of 0 degree ± 5 degrees with respect to the tire circumferential direction. What is necessary is just to be formed so that it may become. Similarly, the 90-degree cord 25 does not need to be formed at an angle of 90 degrees accurately with respect to the tire circumferential direction, and may be formed within a range of 90 degrees ± 5 degrees.

  Similarly to the belt layer 20, the carcass 10 also has a cord, and the cord of the carcass 10, that is, the carcass cord 11 is substantially 90 degrees with respect to the tire circumferential direction like the 90-degree cord 25. It is formed at an angle, and a plurality of carcass cords 11 formed at this angle are arranged in the tire circumferential direction.

  The inner 0 degree cord 22 and the outer 0 degree cord 28 are both formed by a composite cord in which a low elastic fiber and a high elastic fiber are combined. Of the low and high elastic fibers formed by the inner 0 degree cord 22 and the outer 0 degree cord 28, the low elastic fiber is, for example, nylon having low elastic modulus, such as nylon 66 or nylon 46, PET (Polyethylene Terephthalate), rayon or the like, and the high elastic fiber is made of aramid, PEN (Polyethylene Naphthalate), POK (Polyolefine Ketone) or the like having a high elastic modulus. The 90 degree cord 25 is formed of a steel cord.

  When this pneumatic tire 1 is mounted on a vehicle (not shown) and travels, a large load acts on the surface of the tread portion 5, that is, the tread surface 6 that is a surface that contacts the road surface due to the weight of the vehicle. Further, when the vehicle travels, the pneumatic tire 1 rotates in the tire circumferential direction around the rotation axis, and therefore, a load in the tire circumferential direction acts on the pneumatic tire 1. In particular, the larger the vehicle speed, the greater the load acts on this load. However, the belt layer 20 formed on the pneumatic tire 1 includes an inner 0 degree reinforcing layer 21 and an outer 0 degree reinforcing layer 27. Have. The inner 0 degree reinforcement layer 21 and the outer 0 degree reinforcement layer 27 are both an inner 0 degree cord 22 or an outer 0 degree cord 28 which is a cord formed at an angle of substantially 0 degrees with respect to the tire circumferential direction. have. For this reason, both the inner 0 degree reinforcement layer 21 and the outer 0 degree reinforcement layer 27 have high tensile rigidity in the tire circumferential direction, and even when a large tensile load acts in the tire circumferential direction such as when the vehicle is traveling at high speed, The load can be received by the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27. Thereby, even when a large tensile load acts in the tire circumferential direction, the load can be received by the inner 0-degree reinforcing layer 21 and the outer 0-degree reinforcing layer 27. Even in such a case, the belt layer 20 is It becomes difficult to break, and durability during high-speed running can be improved.

  Further, the 90-degree reinforcing layer 24 has a plurality of 90-degree cords 25 that are formed at an angle of substantially 90 degrees with respect to the tire circumferential direction, and the plurality of 90-degree cords 25 are in the tire circumferential direction. And are held by the rubber 26. Further, the 90 degree reinforcing layer 24 is provided in a state sandwiched between the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 in the tire radial direction. Thereby, even when a load is applied to the 90-degree reinforcing layer 24, the rubber 26 located between the 90-degree cords 25 does not deform in the tire radial direction, so that the compression rigidity of the rubber 26 can be utilized. The in-plane bending rigidity of the reinforcing layer 24 can be ensured. Therefore, when a load in the tire circumferential direction and a load in the tire width direction act simultaneously on the pneumatic tire 1 such as during cornering, the load is received by the in-plane bending rigidity of the 90-degree reinforcing layer 24. As a result, steering stability can be improved. As a result, both high-speed durability and steering stability can be improved.

  In addition, since the inner 0 degree cord 22 and the outer 0 degree cord 28 are formed of a composite cord in which a low elastic fiber and a high elastic fiber are combined, it is easy to manufacture the pneumatic tire 1 excellent in high speed durability. can do. That is, by using low elastic fibers for the inner 0 degree cord 22 and the outer 0 degree cord 28, it is possible to follow the lift when the pneumatic tire 1 is molded. Further, by using high elastic fibers for the inner 0 degree cord 22 and the outer 0 degree cord 28, the tensile rigidity in the tire circumferential direction between the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 is improved. Performance against tensile fatigue is improved. Therefore, the tensile load in the tire circumferential direction during high-speed traveling can be more reliably received. As a result, the high-speed durability can be further improved, and the pneumatic tire 1 that can improve both the high-speed durability and the steering stability can be easily manufactured.

  In addition, since the 90 degree cord 25 is formed of a steel cord, the 90 degree cord 25 can be held and the compression rigidity of the rubber 26 positioned between the 90 degree cords 25 can be used more reliably. The in-plane bending rigidity of the strength reinforcing layer 24 can be improved. As a result, the steering stability can be improved more reliably.

  Further, since the width in the tire width direction of the 90-degree reinforcing layer 24 is narrower than the width in the tire width direction of both the inner 0-degree reinforcing layer 21 and the outer 0-degree reinforcing layer 27, the 90-degree reinforcing layer 24. The whole can be sandwiched between the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27. Thereby, the compression rigidity of the rubber 26 included in the 90-degree reinforcing layer 24 can be used more reliably, and the in-plane bending rigidity of the 90-degree reinforcing layer 24 can be improved more reliably. Therefore, the load acting on the pneumatic tire 1 during cornering of the vehicle can be more reliably received by the in-plane bending rigidity of the 90-degree reinforcing layer 24. As a result, the steering stability can be improved more reliably.

  3-5 is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. In the pneumatic tire 1 described above, the inner 0 degree reinforcing layer 21, the 90 degree reinforcing layer 24, and the outer 0 degree reinforcing layer 27 are all provided one by one, and the 90 degree reinforcing layer 24 is provided in the tire width direction. The width in the tire width direction of both the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 is narrower, and the width in the tire width direction of the inner 0 degree reinforcing layer 21 is the outer 0 degree reinforcing layer. 27 is narrower than the width in the tire width direction, but the belt layer 20 may be formed in other forms. For example, as shown in FIG. 3, the width in the tire width direction of the inner 0 degree reinforcement layer 21 may be wider than the width in the tire width direction of the outer 0 degree reinforcement layer 27. Thereby, the rigidity of the shoulder part 8 vicinity of the tread part 5 can be improved, and the steering stability can be improved.

  Further, as shown in FIGS. 4 and 5, the outer 0 degree reinforcing layer 27 may be divided into two parts in the tire width direction in the vicinity of the center part in the tire width direction. Even in this case, the width of the outer 0 degree reinforcing layer 27 is wider than the width of the inner 0 degree reinforcing layer 21 as shown in FIG. 4, or conversely, as shown in FIG. The width of the inner 0 degree reinforcing layer 21 may be wider than the width of 27. Thus, by dividing the outer 0 degree reinforcing layer 27 into two, the tensile rigidity in the tire circumferential direction near the shoulder portion 8 can be made higher than the tensile rigidity in the tire circumferential direction near the center in the tire width direction. it can. As a result, even when a large tensile load in the tire circumferential direction acts near the shoulder portion 8, damage near the belt layer 20 can be suppressed, and durability can be improved. Further, since the outer 0 degree reinforcing layer 27 is not provided near the center in the tire width direction, the weight can be reduced accordingly.

  6-8 is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. A plurality of 90-degree reinforcing layers 24 may be provided. For example, as shown in FIG. 6, two 90-degree reinforcing layers 24 may be stacked in the tire radial direction. Thereby, since the in-plane bending rigidity of the 90-degree reinforcing layer 24 can be ensured more reliably, the in-plane bending rigidity can be increased. As a result, the steering stability can be improved more reliably. Moreover, as shown in FIG.7 and FIG.8, one 90 degree reinforcement layer 24 is a tire width direction in the center part vicinity in a tire width direction among the two 90 degree reinforcement layers 24 piled up by the tire radial direction. It may be divided into two. Thereby, the in-plane bending rigidity in the vicinity of the shoulder portion 8 can be improved, and the rigidity can be ensured even when a large load is applied in the vicinity of the shoulder portion 8. As a result, the steering stability can be improved more reliably.

  9 and 10 are schematic views illustrating modifications of the pneumatic tire according to the embodiment. Moreover, the 90 degree | times reinforcement layer 24 may be formed in the folded structure by which the edge part in the tire width direction was return | folded. For example, as shown in FIG. 9, the end portion in the tire width direction of the 90-degree reinforcing layer 24 may be folded outward in the tire radial direction, and as shown in FIG. The end in the tire width direction may be folded back inward in the tire radial direction. As described above, the end of the 90-degree reinforcing layer 24 in the tire width direction is folded, and the folded portions are overlapped, whereby the rigidity of the portion can be further improved. Further, when the 90-degree reinforcing layer 24 is overlapped in the tire radial direction, since the end of one 90-degree reinforcing layer 24 is folded and overlapped, the edge of the end of the 90-degree reinforcing layer 24 in the tire width direction is Disappear. For this reason, it is possible to suppress damage such as the occurrence of separation starting from the edge portion of the end portion of the 90-degree reinforcing layer 24. As a result, the steering stability can be further improved and the durability can be improved.

  Hereinafter, the performance evaluation test performed on the conventional pneumatic tire 1 and the pneumatic tire 1 of the present invention will be described. The performance evaluation test was conducted on two items, high-speed durability and steering stability.

  The test method was performed by assembling the 225 / 45R17 size pneumatic tire 1 on a rim defined by JATMA, setting the normal air pressure, and applying a normal load. As for the evaluation method of each test item, as for high-speed durability, first, a JIS high-speed durability test is performed according to JIS D-4230 using a drum having a drum diameter of 1707 mm. Thereafter, the drum rotation speed is further accelerated by 10 km / h every 30 minutes, the test is performed until the pneumatic tire 1 is damaged, and the rotation speed of the drum when the pneumatic tire 1 is damaged is measured. This measurement result was shown by the index | exponent which set the measurement result of the pneumatic tire 1 of the prior art example mentioned later as 100. The higher the index, the better the high-speed durability.

  As for steering stability, the vehicle is fitted with a pneumatic tire 1 to be tested and travels on a test course having a flat circuit at 80 km / h to 250 km / h at the time of rail change and cornering. Steerability and stability in straight running are performed by sensory evaluation by three specialized panelists. This evaluation result was shown by the index which set the evaluation result of the pneumatic tire 1 of the prior art example mentioned later as 100. The larger the index, the better the steering stability. In this evaluation test, an index improved in both the two items was considered effective.

  The pneumatic tire 1 to be tested is tested by the above-described method for four types of the present invention, two types of comparative examples to be compared with the present invention, and one type of conventional example. The conventional pneumatic tire has a belt layer of a cross belt structure by two reinforcing layers having cords formed at an angle of 27 degrees with respect to the tire circumferential direction. Both the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 sandwiched in the tire radial direction are provided. Among these, the cross belt having a 27-degree cord is formed of a 1 × 6 steel cord, and both the inner 0-degree cord 22 and the outer 0-degree cord 28 are formed of 66 nylon fibers.

  Further, in Comparative Example 1, which is an example of the comparative example, the 90-degree reinforcing layer 24 and the outer 0-degree reinforcing layer 27 are provided one by one, and the 90-degree cord 25 is formed of 1 × 6 steel cord. The outer 0 degree cord 28 is formed of a composite cord (hereinafter referred to as an aramid / nylon hybrid fiber) obtained by twisting an aramid fiber and a 66 nylon fiber. In Comparative Example 2, only the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 are provided one by one, and the inner 0 degree cord 22 and the outer 0 degree cord 28 are aramid / nylon hybrids. It is formed by fibers.

  On the other hand, the present inventions 1 to 4 all have the inner 0 degree reinforcing layer 21, the 90 degree reinforcing layer 24, and the outer 0 degree reinforcing layer 27, and the 90 degree reinforcing layer 24 is referred to as the inner 0 degree reinforcing layer 21. The outer 0-degree reinforcing layer 27 is provided so as to be sandwiched in the tire radial direction. Of these, the present invention 1 includes the inner 0 degree reinforcing layer 21, the 90 degree reinforcing layer 24, and the outer 0 degree reinforcing layer 27, one by one. The inner 0 degree cord 22 and the outer 0 degree cord 28 are , 66 nylon fiber, and the 90 degree cord 25 is formed of 1 × 6 steel cord. Further, in the present invention 2, the inner 0 degree reinforcing layer 21, the 90 degree reinforcing layer 24, and the outer 0 degree reinforcing layer 27 are all provided one by one, and the inner 0 degree cord 22 and the outer 0 degree cord 28 are The 90 degree cord 25 is formed of an aramid / nylon hybrid fiber, and is formed of a 1 × 6 steel cord.

  Further, according to the third aspect of the present invention, the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 are provided one by one, and the two 90 degree reinforcing layers 24 are provided, and the inner 0 degree cord 22 and the outer 0 degree cord are provided. The cord 28 is formed of an aramid / nylon hybrid fiber, and the 90 degree cord 25 is formed of a 1 × 6 steel cord. In the present invention 4, the inner 0 degree reinforcing layer 21, the 90 degree reinforcing layer 24, and the outer 0 degree reinforcing layer 27 are all provided one by one, and the 90 degree reinforcing layer 24 has a folded structure. . Moreover, in this invention 4, the inner side 0 degree cord 22 and the outer side 0 degree cord 28 are formed of an aramid / nylon hybrid fiber, and the 90 degree cord 25 is formed of a 1 × 6 steel cord.

  These conventional examples, comparative example 1 and comparative example 2, and pneumatic tires 1 of the present invention 1 to 4 are subjected to an evaluation test by the above method, and the obtained results are shown in Table 1-1 and Table 1-2. Table 1-1 displays the test results of Conventional Example, Comparative Example 1, and Comparative Example 2, and Table 1-2 displays the test results of Inventions 1 to 4.

  As is clear from the above test results shown in Table 1-1 and Table 1-2, the tire circumferential direction can be obtained only by providing the 90-degree reinforcing layer 24 and the outer 0-degree reinforcing layer 27 one by one. Since the tensile rigidity of is not so high, it is difficult to improve high-speed durability (Comparative Example 1). Further, when the 90-degree reinforcing layer 24 is not sandwiched in the tire radial direction, it is difficult to ensure the inner surface bending rigidity of the 90-degree reinforcing layer 24, and thus it becomes difficult to improve the steering stability (Comparative Example 1). ). Further, when only the inner 0 degree reinforcing layer 21 and the outer 0 degree reinforcing layer 27 are provided, the tensile rigidity in the tire circumferential direction is increased, so that high-speed durability can be improved. Since it becomes difficult to ensure bending rigidity, it is difficult to improve steering stability (Comparative Example 2).

  On the other hand, as in the present inventions 1 to 4, the 90-degree reinforcing layer 24 is sandwiched between the inner 0-degree reinforcing layer 21 and the outer 0-degree reinforcing layer 27 in the tire radial direction, thereby improving the tensile rigidity in the tire circumferential direction. Thus, durability during high-speed traveling can be improved, and in-plane bending rigidity of the 90-degree reinforcing layer 24 can be secured, so that steering stability can be improved. As a result, both high speed durability and steering stability can be improved.

  As described above, the pneumatic tire according to the present invention is useful for a pneumatic tire having a plurality of belt layers, and is particularly suitable for a pneumatic tire used at high speeds.

It is a meridional sectional view showing the main part of the pneumatic tire according to the present invention. It is AA sectional drawing of FIG. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment. It is the schematic which shows the modification of the pneumatic tire which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 3 Equatorial surface 5 Tread part 6 Tread surface 7 Side wall part 8 Shoulder part 10 Carcass 11 Carcass cord 15 Inner liner 16 Bead part 17 Bead core 18 Bead filler 20 Belt layer 21 Inner 0 degree reinforcement layer 22 Inner 0 degree cord 24 90 degree reinforcement layer 25 90 degree cord 26 Rubber 27 Outside 0 degree reinforcement layer 28 Outside 0 degree cord

Claims (5)

An inner 0 degree reinforcing layer having an inner 0 degree cord formed at an angle of substantially 0 degree with respect to the tire circumferential direction, at least one piece being provided radially outward of the carcass;
At least one sheet is provided on the outer side in the tire radial direction of the inner 0 degree reinforcing layer, and has a 90 degree cord formed at an angle of substantially 90 degrees with respect to the tire circumferential direction, and the 90 degrees A 90-degree reinforcing layer in which the cord is held by an elastic member;
The outer 0 degree reinforcing layer having an outer 0 degree cord provided at least one on the outer side in the tire radial direction of the 90 degree reinforcing layer and formed at an angle of substantially 0 degree with respect to the tire circumferential direction. When,
A pneumatic tire characterized by comprising:   2. The pneumatic tire according to claim 1, wherein at least one of the inner 0-degree cord and the outer 0-degree cord is formed of a composite cord in which a low elastic fiber and a high elastic fiber are combined.   The pneumatic tire according to claim 1, wherein the 90-degree cord is made of a steel cord.   The end portion in the tire width direction of the 90-degree reinforcing layer is folded back on the outer side in the tire radial direction or the inner side in the tire radial direction. The described pneumatic tire.   The width in the tire width direction of the 90-degree reinforcing layer is narrower than the width in the tire width direction of the inner 0-degree reinforcing layer and the outer 0-degree reinforcing layer. Pneumatic tire described in 2.

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