JP6699107B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire provided with a reinforcing member used for a reinforcing layer represented by a belt layer, and more specifically, it has an in-plane bending rigidity while maintaining good flexibility against out-of-plane deformation of the reinforcing member. The present invention relates to a pneumatic tire that can be increased and, in turn, has increased cornering power and reduced rolling resistance.

  In a pneumatic tire, a carcass layer is mounted between a pair of bead portions, and a belt layer is arranged on the outer peripheral side of the carcass layer in the tread portion. As the belt layer, a reinforcing member including a plurality of reinforcing cords inclined with respect to the tire circumferential direction is used, and the reinforcing cords are arranged so as to intersect each other between the layers of the belt layer (for example, Patent Documents 1 to 1). 3).

  Here, by increasing the in-plane bending rigidity of the reinforcing member used for the belt layer, it is possible to increase the cornering power and reduce the rolling resistance. However, in the conventional reinforcing member, since the binding between the reinforcing cords is weak, it is not always possible to exhibit sufficient in-plane bending rigidity. Although it is possible to increase the in-plane bending rigidity by making the reinforcing cord itself rigid, in that case, the flexibility of the reinforcing member against out-of-plane deformation is impaired.

  On the other hand, a reinforcing member having a net-like structure in which two reinforcing cords are joined to each other at an intersection has been proposed (for example, see Patent Document 4). However, the effect of increasing the in-plane bending rigidity of the reinforcing member is hardly obtained by simply joining the two reinforcing cords that intersect with each other, and the effect of increasing the cornering power and the effect of reducing the rolling resistance cannot be expected.

JP 61-1505 A Japanese Patent Laid-Open No. 1-501382 JP-A-6-211003 International Publication No. WO2015-8547

  An object of the present invention is to increase the in-plane bending rigidity while maintaining good flexibility of the reinforcing member against out-of-plane deformation, and, in turn, to increase cornering power and reduce rolling resistance. It is to provide a pneumatic tire made possible.

The pneumatic tire of the present invention for achieving the above-mentioned object, a tread portion which extends in the tire circumferential direction and forms an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions. And a pair of bead portions arranged on the inner side in the tire radial direction , a carcass layer is mounted between the pair of bead portions, and a pneumatic tire in which a belt layer is arranged on the outer peripheral side of the carcass layer in the tread portion In, a plurality of reinforcing cords oriented in at least three directions are included, and a reinforcing member having a mesh structure in which at least three reinforcing cords having different orientation directions are joined to each other at at least a part of intersections of these reinforcing cords , The reinforcing member having the mesh structure is used as the belt layer, and the density of the joint portion of the reinforcing cord in the reinforcing member is increased toward the outer side in the tire width direction .

  In the present invention, the reinforcing member includes a plurality of reinforcing cords oriented in at least three directions, and has a net-like structure in which at least three reinforcing cords having different orientation directions are joined to each other at an intersection of at least a part of these reinforcing cords. Since it has, the in-plane bending rigidity can be increased while maintaining good flexibility against the out-of-plane deformation.

  Therefore, in a pneumatic tire in which a carcass layer is mounted between a pair of bead portions, and a belt layer is arranged on the outer peripheral side of the carcass layer in the tread portion, when a reinforcing member having the above-mentioned mesh structure is used as the belt layer, The cornering power can be increased and the rolling resistance can be reduced. Moreover, since the reinforcing member exhibits good flexibility against out-of-plane deformation, the durability of the belt layer can be maintained well.

  In the present invention, at least three reinforcing cords are preferably joined to each other at at least 30% of the intersecting points where at least three reinforcing cords intersect. Thereby, the effect of increasing the in-plane bending rigidity can be sufficiently obtained.

  Further, it is preferable that the intersecting angle of at least three reinforcing cords joined at the intersecting point is 15° or more. Thereby, the effect of increasing the in-plane bending rigidity can be sufficiently obtained.

  The belt layer may be formed by winding a reinforcing member having a net-like structure one or more turns along the tire circumferential direction, or by forming the reinforcing member having a net-like structure into an endless annular shape. It may be. In the former case, the tire is easy to manufacture, and in the latter case, the tire has good durability.

  The reinforcing cord preferably contains a chemical fiber cord having a knot strength of 1.5 (cN/dtex) or more. In the case of a chemical fiber cord, a reinforcing member having a network structure can be easily formed, and a chemical fiber cord having the above knot strength is suitable as a tire reinforcing material.

  Further, it is preferable that the reinforcing member having the mesh structure is covered with rubber. Thereby, the integrity of the reinforcing cord can be secured and the in-plane bending rigidity of the reinforcing member can be increased.

It is a meridian sectional view showing a pneumatic tire which consists of an embodiment of the present invention. It is a top view showing an example of the reinforcing member used for the belt layer of the pneumatic tire of the present invention. It is explanatory drawing which shows the deformation|transformation mechanism of the reinforcing member which has the net-like structure which joined together the at least 3 reinforcing cords from which the orientation directions differ at the intersection of a reinforcing cord. It is explanatory drawing which shows the deformation|transformation mechanism of the reinforcing member which has the net-like structure which joined two reinforcing cords from which the orientation directions differ at the intersection of reinforcing cords mutually. It is a top view which shows the modification of the reinforcing member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows the other modification of the reinforcement member used for the belt layer of the pneumatic tire of this invention. It is a top view which shows an example of the junction part of the reinforcement member used by this invention. It is a top view which shows the modification of the joint part of the reinforcement member used by this invention. It is a top view which shows the other modification of the joining part of the reinforcement member used by this invention. It is a top view which shows the other modification of the joining part of the reinforcement member used by this invention. It is a top view which shows the other modification of the joining part of the reinforcement member used by this invention. It is a perspective view which shows the other modification of the joining part of the reinforcing member used by this invention. It is a top view which shows the other modification of the joining part of the reinforcement member used by this invention. It is a top view which shows the other modification of the joining part of the reinforcement member used by this invention. It is a perspective view which shows the other modification of the joining part of the reinforcing member used by this invention. It is a perspective view which shows the other modification of the joining part of the reinforcing member used by this invention. It is a perspective view which shows the other modification of the joining part of the reinforcing member used by this invention. It is a perspective view which shows the other modification of the joining part of the reinforcing member used by this invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 1, the pneumatic tire of the present embodiment has a tread portion 1 extending in the tire circumferential direction and forming an annular shape, and a pair of sidewall portions 2 and 2 arranged on both sides of the tread portion 1. And a pair of bead portions 3 disposed inside the sidewall portion 2 in the tire radial direction.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the tire inner side to the outer side around the bead core 5 arranged in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross section is arranged on the outer periphery of the bead core 5.

  On the other hand, a belt layer 7 is embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. The belt layer 7 is composed of a reinforcing member 10 having a specific net-like structure described later. On the outer peripheral side of the belt layer 7, for the purpose of improving high-speed durability, there is arranged at least one belt cover layer 8 in which reinforcing cords are arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction. There is. As the reinforcing cord of the belt cover layer 8, a chemical fiber cord such as nylon or aramid is preferably used. The belt cover layer 8 is not always necessary.

  FIG. 2 shows an example of a reinforcing member used in the belt layer of the pneumatic tire of the present invention. As shown in FIG. 2, the reinforcing member 10 having a net-like structure includes a plurality of reinforcing cords 11 to 14 oriented in four directions. That is, the reinforcement cord 11 extends parallel to the tire circumferential direction C, the reinforcement cord 12 extends parallel to the tire width direction W, and the reinforcement cord 13 is inclined to one side with respect to the tire circumferential direction C. The reinforcing cord 14 extends so as to incline to the other side with respect to the tire circumferential direction C. At the intersections of the reinforcing cords 11 to 14, a plurality of reinforcing cords 11 to 14 having different orientations are joined to each other to form a plurality of joints 15 and 16. More specifically, at a crossing point where at least three reinforcing cords 11 to 14 intersect, at least three reinforcing cords 11 to 14 are integrally joined to form a plurality of joints 15, and two joining cords 15 are formed. At the intersection where the reinforcing cords 13 and 14 intersect, the two reinforcing cords 13 and 14 are integrally joined to form a plurality of joint portions 16.

  The material of the reinforcing cords 11 to 14 is not particularly limited, and chemical fiber cords or steel cords can be used as the reinforcing cords 11 to 14. For example, a structure using chemical fiber cords for all the reinforcing cords 11 to 14, a structure using chemical fiber cords for the reinforcing cords 11, 13, and 14 while using a steel cord for the reinforcing cords 12, steel for the reinforcing cords 11 Examples of the structure include a cord using chemical fiber cords for reinforcing cords 12 to 14, and a steel cord for reinforcing cords 11 and 12 while using chemical fiber cords for reinforcing cords 13 and 14. it can.

  The method of joining the reinforcing cords 11 to 14 is not particularly limited, and various methods can be adopted. In the case of a chemical fiber cord, the joint portions 15 and 16 are formed so that the cords form a knot, or the cords are joined so that both fiber bundles (yarns) intersect each other without forming a knot. The portions 15 and 16 can be formed, the joint portions 15 and 16 can be formed by welding the cords together, and the joint portions 15 and 16 can be formed by adhering the cords together. In the case of a steel cord, the joints 15 and 16 are formed so that the filaments of the cords intersect each other without forming a knot, or the joints 15 and 16 are formed by welding the cords together. The bonding portions 15 and 16 can be formed by bonding the cords together. In any case, it is necessary that the cords are integrally connected at the intersection so as to regulate the positions of the cords.

  The reinforcing member 10 configured as described above includes a plurality of reinforcing cords 11 to 14 oriented in at least three directions, and at least three different oriented directions at intersections of at least a part of these reinforcing cords 11 to 14. Since it has a net-like structure in which the reinforcing cords 11 to 14 are joined to each other, it is possible to increase the in-plane bending rigidity while maintaining good flexibility against the out-of-plane deformation.

  FIG. 3 shows a deformation mechanism of a reinforcing member having a mesh structure in which at least three reinforcing cords having different orientations are joined to each other at the intersection of the reinforcing cords, and FIG. FIG. 3 shows a deformation mechanism of a reinforcing member having a net structure in which the reinforcing cords of FIG. As shown in FIG. 4, a reinforcing member 10A having a mesh structure in which two reinforcing cords 11 and 12 having different orientations are joined to each other at the intersection of the reinforcing cords 11 and 12 has a pantograph when a force acts in the plane direction. It transforms like. On the other hand, as shown in FIG. 3, the reinforcing member 10 having a net-like structure in which at least three reinforcing cords 11 to 14 having different orientations are joined to each other at intersections of the reinforcing cords 11 to 14 has a planar structure. It has a truss structure, is hard to be deformed even when a force is applied to its surface direction, and has high in-plane bending rigidity.

  Therefore, in the pneumatic tire in which the carcass layer 4 is mounted between the pair of bead portions 3 and 3 and the belt layer 7 is arranged on the outer peripheral side of the carcass layer 4 in the tread portion 1, the above net-like structure is used as the belt layer 7. When the reinforcing member 10 included therein is used, cornering power can be increased and rolling resistance can be reduced. In addition, since the reinforcing member 10 exhibits good flexibility against out-of-plane deformation, the durability of the belt layer 7 can be maintained well.

  In the pneumatic tire, at least three reinforcing cords 11 to 14 are joined to each other at all intersections where at least three reinforcing cords 11 to 14 intersect, but at least three reinforcing cords 11 to 14 are joined. It is desirable to join at least three reinforcing cords 11 to 14 to each other at at least 30% of the intersecting points, more preferably at least 50% (most preferably 70% or more) of the intersecting points. .. Thereby, the effect of increasing the in-plane bending rigidity can be sufficiently obtained. If this ratio is too small, the effect of improving the in-plane bending rigidity decreases.

  In the pneumatic tire, the crossing angle of at least three reinforcing cords 11 to 14 joined at the crossing point is 15° or more, and more preferably 20° to 75°. Thereby, the effect of increasing the in-plane bending rigidity can be sufficiently obtained. If this intersection angle is too small, the effect of improving the in-plane bending rigidity will be reduced. In addition, in the embodiment of FIG. 2, the crossing angle of the reinforcing cords 11 to 14 is 45°.

  5 to 8 show modified examples of the reinforcing member used in the belt layer of the pneumatic tire of the present invention. In FIG. 5, at least three reinforcing cords 11 to 14 are integrally joined to each other to form a plurality of joints 15 at intersections where at least three reinforcing cords 11 to 14 intersect, but two joint cords 15 are formed. The joint portion 16 is not formed at the intersection where the reinforcing cords 13 and 14 intersect.

  In FIG. 6, unlike FIG. 5, the reinforcing cords 11 extending in the tire circumferential direction C are not arranged at both end positions of the reinforcing member 10 in the tire width direction W. Unlike FIG. 5, in FIG. 7, the reinforcing cord 11 and the joint portion 15 extending in the tire circumferential direction C are not arranged at both end positions in the tire width direction W of the reinforcing member 10. In contrast to FIG. 5, in FIG. 8, joint portions 16 are selectively formed at the intersections where the two reinforcing cords 13 and 14 intersect at both ends of the reinforcing member 10 in the tire width direction W.

  FIG. 9 shows another modification of the reinforcing member used in the belt layer of the pneumatic tire of the present invention. FIG. 9 shows only one side of the tire center line CL. In FIG. 9, at least three reinforcing cords 11 to 14 are integrally joined to form a plurality of joints 15 at least at some intersections where the at least three reinforcing cords 11 to 14 intersect, and two joining cords 15 are formed. The two reinforcing cords 13 and 14 are integrally joined to each other to form a joint portion 16 at at least a part of the intersection where the reinforcing cords 13 and 14 intersect. When the reinforcing member 10 is divided into four areas A1 to A4 from the tire center line CL toward the outer side in the tire width direction, the density of the joint portions 15 and 16 in these areas A1 to A4 becomes higher toward the outer side in the tire width direction. Is set. With such an arrangement, the cornering power can be increased more effectively and the rolling resistance can be reduced more effectively.

  FIG. 10 shows another modification of the reinforcing member used in the belt layer of the pneumatic tire of the present invention. In FIG. 10, the reinforcing member 10 having a net-like structure includes a plurality of reinforcing cords 11, 13 and 14 oriented in three directions. That is, the reinforcement cord 11 extends in parallel with the tire circumferential direction C, the reinforcement cord 13 extends so as to incline to one side with respect to the tire circumferential direction C, and the reinforcement cord 14 with respect to the tire circumferential direction C. It extends so as to incline to the other side. At the intersection where the three reinforcing cords 11, 13, 14 intersect, the three reinforcing cords 11, 13, 14 are integrally joined to form a plurality of joints 15.

  The belt layer 7 described above can be formed by winding the reinforcing member 10 having a net-like structure one or more times along the tire circumferential direction. In this case, since the reinforcing member 10 having the net-like structure can be handled in the same manner as the conventional belt member, the pneumatic tire can be easily manufactured. Further, it is desirable that the reinforcing member 10 be wound twice or more along the tire circumferential direction. At this time, the positions of the joint portions 15 and 16 may be different for each revolution.

  11 and 12 show another modification of the reinforcing member used in the belt layer of the pneumatic tire of the present invention. 11, in the structure in which the reinforcing member 10 having a net-like structure is wound twice, the joining portion 15 of the first layer (broken line) on the inner side in the tire radial direction and the second layer (solid line) on the outer side in the tire radial direction are shown. The joint portion 15 and the joint portion 15 are displaced from each other in the tire circumferential direction C. In FIG. 12, in the structure in which the reinforcing member 10 having a net-like structure is wound twice, the joining portion 15 of the first layer (broken line) on the inner side in the tire radial direction and the second layer (solid line) on the outer side in the tire radial direction are The joint portion 15 and the joint portion 15 are displaced from each other in the tire width direction W.

  Alternatively, the belt layer 7 described above can be formed by processing the reinforcing member 10 having a net-like structure into an endless annular shape. That is, the reinforcing member 10 can be formed by braiding in a ring shape. In this case, the durability of the pneumatic tire becomes good. Further, it is possible to form the belt layer 7 by preparing endless annular reinforcing members 10 having different diameters and stacking them. In such a case, the positions of the joint portions 15 and 16 may be different between the layers.

  In the pneumatic tire, the reinforcing cords 11 to 14 have a tensile strength of 1.5 (cN/dtex) or more, a knot strength of 1.5 (cN/dtex) or more, and a hooking strength of 2.5( It is desirable to use a chemical fiber cord having a cN/dtex) or more. In the case of the chemical fiber cord, the reinforcing member 10 having a mesh structure can be easily formed, and the chemical fiber cord having the above physical properties is suitable as a tire reinforcing material.

  Regarding the above physical properties, preferably, the tensile strength is 2.0 (cN/dtex) or more, the knot strength is 2.0 (cN/dtex) or more, and the hooking strength is 3.5 (cN/dtex) or more. More preferably, the tensile strength is 4.0 (cN/dtex) or more, the knot strength is 3.0 (cN/dtex) or more, and the hooking strength is 5.0 (cN/dtex) or more, and most preferable. Has a tensile strength of 5.0 (cN/dtex) or more, a knot strength of 4.0 (cN/dtex) or more, and a hooking strength of 8.0 (cN/dtex) or more. The upper limit is not particularly limited, but the knot strength is 20 (cN/dtex) or less, the hooking strength is 20 (cN/dtex) or less, and the tensile strength is 15 (cN/dtex) or less. Is realistic. The knot strength and the hooking strength are measured according to JIS-L1013 (chemical fiber filament yarn test method) and JIS-L1015 (chemical fiber staple test method), respectively.

  Such chemical fiber cords include aramid fiber, polyketone fiber, polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, high molecular weight polyethylene fiber (Toyobo Dyneema, etc.), poly-paraphenylene benzobisoxazole (PBO). Those containing fibers are preferred. Of course, it is possible to change the material according to the cord extension direction. Further, a composite cord obtained by twisting fibers made of a low elongation material (for example, aramid fiber) and fibers made of a high elongation material (for example, nylon fiber) has a knot strength due to the characteristics of the high elongation material. Is high, and the elastic modulus is high due to the characteristics of the low-elongation material. Therefore, it is suitable as a material for the reinforcing member 10 having a mesh structure. When the chemical fiber cords are tied together, it may be knotted or knotless, but it is preferable to use knotless from the viewpoint of thinning the member.

  The thickness of the reinforcing cords 11 to 14 is preferably 0.5 mm to 1.5 mm. If this thickness exceeds the upper limit value, the rubber layer becomes thicker and the weight of the tire increases, so the rolling resistance deteriorates.If the thickness falls below the lower limit value, it is necessary to increase the number of cords arranged to secure the same strength. As a result, the density of the joining points becomes too high, which makes it difficult to manufacture the reinforcing member 10.

  The reinforcing member 10 forming the belt layer 7 is preferably covered with rubber. As a result, the integrity of the reinforcing cords 11 to 14 can be secured and the in-plane bending rigidity of the reinforcing member 10 can be increased.

  Next, the joint portion of the reinforcing member used in the present invention will be specifically described with reference to FIGS. 13 to 24. FIG. 13 shows an example in which three cords 21 to 23 are joined to each other, but the cords 22 and 23 individually form a nodule so as to be entangled with the cord 21 having no knot. FIG. 14 shows an example in which the three cords 21 to 23 are joined to each other, but the cord 23 forms a knot so as to be entangled with the cords 21 and 22 having no knot. FIG. 15 shows an example in which the three cords 21 to 23 are joined to each other, but the cords 22 and 23 individually form a knot so that they are entangled with the cord 21 having no knot, and the cords 22 and 23 are inclined. Is reversed at the nodule. FIG. 16 shows an example in which three cords 21 to 23 are joined to each other. However, the cord 23 forms a knot so that it is entangled with the cords 21 and 22 having no knot, and the cords 22 and 23 are inclined in the knot direction. It is reversed at the border. FIG. 17 shows an example in which three cords 21 to 23 are joined to each other, but the cords 22 and 23 individually form a knot so that they are entangled with the cord 21 having no knot, and these knots are engaged with each other. The inclination directions of the cords 22 and 23 are reversed at the nodule. FIG. 18 shows an example in which the three cords 21 to 23 are joined to each other, but the cords 22 and 23 integrally form a knot so as to be entangled with the cord 21 having no knot, and the cords 22 and 23 are inclined. The direction is reversed at the nodule.

  FIG. 19 shows an example in which four cords 21 to 24 are joined to each other, but the cord 22 forms a knot so as to be entangled with the cords 21, 23 and 24 having no knot. FIG. 20 shows an example in which four cords 21 to 24 are joined to each other, but the cords 22 and 23 individually form a nodule so as to be entangled with the cord 21 having no knot, and the cords 22 and 23 are inclined. Is reversed at the nodule, and the cord 24 is inserted between these 22 and 23. 13 to 20, for example, the cord 21 having no knot is preferably oriented in the tire circumferential direction. When the cords 21 are arranged in the tire circumferential direction, a large tension is applied to the cords 21, but the tension can be effectively carried by not having the curvature due to the knot.

  FIG. 21 shows an example in which three cords 21 to 23 are joined to each other by welding. When the cords 21 to 23 are chemical fibers and at least a part of the cords is made of a thermoplastic resin, heat welding, ultrasonic welding, or the like may be performed while compressing the intersecting portions of the cords 21 to 23 in the thickness direction. The cords 21 to 23 can be integrated by performing the welding process. FIG. 22 shows an example in which two cords 21 and 22 are joined to each other by welding.

  FIG. 23 shows an example in which two cords 21 and 22 are joined to each other by another welding method. When the cords 21 and 22 are chemical fibers and are composed of a thermosetting resin, a bonding material made of a thermoplastic resin so as to impregnate or wrap the fibers at the intersections of the cords 21 and 22. The cords 21 and 22 can be integrated by arranging 25 and performing a welding treatment such as heat welding or ultrasonic welding on the cord 25.

  FIG. 24 shows an example in which two cords 21 and 22 are joined to each other without knots, and the yarns forming the cords 21 and 22 intersect each other to form a knotless joint. When the joint having the knot is formed, the reinforcing member 10 becomes thick, but when the joint having no knot is formed, the thickness of the reinforcing member 10 can be reduced.

  In the above-described embodiment, the case where the reinforcing member having a specific net-like structure is applied to the belt layer has been described, but the reinforcing member having such a specific net-like structure is applied to various reinforcing layers constituting the pneumatic tire. It is possible. When applied to any of the reinforcing layers, various tire performances can be improved by increasing the in-plane bending rigidity while maintaining good flexibility against out-of-plane deformation.

  With a tire size of 215/55R17, a tread portion extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a tire radial direction inner side of these sidewall portions are arranged. A pair of bead portions, a carcass layer is mounted between the pair of bead portions, and the belt layer is arranged on the outer peripheral side of the carcass layer in the tread portion, and the belt layer is oriented in at least three directions. And a reinforcing member (FIG. 2, FIG. 5, FIG. 8, FIG. 10) having a net structure in which at least three reinforcing cords having different orientations are joined to each other at intersections of the reinforcing cords. The tires of Examples 1 to 4 used were manufactured.

  For comparison, a pneumatic tire of a conventional example was prepared in which two belt layers in which the reinforcing cords were inclined in different directions with respect to the tire circumferential direction were embedded in the tread portion. In addition, as a belt layer, a comparative example using a reinforcing member including a plurality of reinforcing cords oriented in two directions and having a mesh structure in which two reinforcing cords having different orientations are joined to each other at intersections of the reinforcing cords. Prepared tires.

  The cornering power and rolling resistance of these test tires were evaluated by the following evaluation methods, and the results are shown in Table 1.

Cornering power:
Each test tire was mounted on a wheel with a rim size of 17×7J, mounted on a flat belt tester, run under conditions of an air pressure of 230 kPa, a load of 6.5 kN and a speed of 20 km/h, and a slip angle was ±1.0°. The cornering power at that time was measured. The evaluation results are shown by an index with the conventional example being 100. The larger the index value, the larger the cornering power.

Rolling resistance:
Each test tire was mounted on a wheel with a rim size of 17×7J and mounted on a rolling resistance tester equipped with a drum having a radius of 854 mm. After 30 minutes of preliminary running, the rolling resistance was measured under the same conditions. The evaluation results are shown by an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the smaller the rolling resistance.

  As can be seen from Table 1, in the tires of Examples 1 to 4, the cornering power was increased and the rolling resistance was decreased in comparison with the conventional example. On the other hand, in the tires of the comparative examples, the cornering power and rolling resistance were hardly improved.

DESCRIPTION OF SYMBOLS 1 tread part 2 sidewall part 3 bead part 4 carcass layer 5 bead core 6 bead filler 7 belt layer 8 belt reinforcing layer 10 reinforcing members 11 to 14 reinforcing cords 15 and 16 joint parts

Claims (7)

An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged on the tire radial inner side of these sidewall portions. A pneumatic tire in which a carcass layer is mounted between the pair of bead portions, and a belt layer is arranged on the outer peripheral side of the carcass layer in the tread portion , including a plurality of reinforcing cords oriented in at least three directions. A reinforcing member having a reticulated structure in which at least three reinforcing cords having different orientations are joined to each other at at least a portion of intersection of these reinforcing cords, and the reinforcing member having the reticulated structure is used as the belt layer, A pneumatic tire characterized in that the density of the joint portion of the reinforcing cord in the reinforcing member is increased toward the outer side in the tire width direction . The pneumatic tire according to claim 1, characterized in that the joined together at least three reinforcement cord at least 30% of the intersections of the intersections at least three reinforcing cords of crossed. The pneumatic tire according to any one of claims 1-2 in which the crossing angle of the reinforcing cords of the at least three be joined, characterized in that at 15 ° or more at the intersections. The pneumatic tire according to any one of claims 1 to 3, wherein the belt layer is characterized by being molded by turning the winding reinforcing member one round or along the tire circumferential direction with the network. The pneumatic tire according to any one of claims 1 to 3, wherein the belt layer is characterized in that it has been formed by processing a reinforcing member having the mesh structure of the non-terminal ring. The pneumatic tire according to any one of claims 1 to 5, wherein said reinforcing cords, characterized in that the knot strength comprises a chemical fiber cord is 1.5 (cN / dtex) or more. The pneumatic tire according to any one of claims 1 to 6 the reinforcing member having the mesh structure, characterized in that it is coated with rubber.

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