JP5961431B2 - Tire reinforcement and pneumatic tire - Google Patents

Description

  The present invention relates to a tire reinforcing material and a pneumatic tire, and in particular, both side areas have a cord braided structure, and the central area has a cord overlapping structure to improve durability. The present invention relates to a tire reinforcing material and a pneumatic tire using the tire reinforcing material.

  As a reinforcing layer for a belt or a carcass itself of a pneumatic tire or a belt, a carcass or a bead portion, a belt-like tire in which a plurality of cord layers formed by rubber coating a cord group in which a plurality of cords are arranged in parallel with each other Reinforcing materials are known. In this tire reinforcing material, the extending directions of the cords are different between the laminated cord layers, that is, between the laminated cord groups, that is, the cords cross each other. As described above, when the reinforcing material for a tire is applied to the tire by causing the cords to cross each other, the cord may bear the force even when forces in various directions are applied to the pneumatic tire. Therefore, the reinforcement effect by the tire reinforcing material can be enhanced (see, for example, Patent Document 1).

  However, in the above-described tire reinforcing material, since the cords are overlapped between the stacked cord groups, the restraint force of the cords is weak and shear strain is likely to occur. In general, in the case of a tire reinforcing material, when shear strain occurs, separation occurs with the surrounding rubber starting from the end face of the cord having weak adhesive strength with the rubber. Therefore, in the tire reinforcing material described above, separation is likely to occur between the rubber and the cord, particularly in the side area. Therefore, the durability performance of the pneumatic tire to which the tire reinforcing material is applied is not sufficient.

  Therefore, a method has been proposed in which cords are knitted (matched) between the laminated cord groups over the entire surface of the tire reinforcing material. In the tire reinforcing material, since the entire surface has a braided structure, the binding force of the cord is increased between the cord groups. Therefore, generation | occurrence | production of the separation in the side area of the reinforcing material for tires can be suppressed, and the durability performance of the said conventional pneumatic tire can be improved by extension (for example, refer patent document 1).

Japanese Patent No. 4357092

  However, in the conventional tire reinforcing material, since the cord is knitted between the laminated cord groups over the entire surface of the tire reinforcing material including the central region of the tire reinforcing material, the cord is laminated. It has a wave shape that swells in the direction. Here, the corrugated cord moves in the direction in which the cord is linearized with respect to tension, that is, in the laminating direction, and therefore has a larger displacement in the laminating direction than the linear cord. Therefore, when the input of tension is repeated with internal pressure filling and rolling for the pneumatic tire to which the conventional tire reinforcing material is applied, the input amount is such that the cord becomes a linear shape. It becomes larger compared to a pneumatic tire to which a reinforcing material for a tire in which groups are laminated is applied. Then, the deformation of the rubber contained in the tire reinforcing material and the accompanying heat generation become relatively large, and the rubber is oxidized and easily cured. Since the cured rubber lowers the durability of adhesion to the cord, separation between the rubber and the cord tends to occur. Therefore, the durability performance of the conventional pneumatic tire to which the above-mentioned conventional tire reinforcing material having a knitted structure is applied has not been sufficient.

  Therefore, the present invention provides a strip-shaped tire reinforcing material in which cords intersecting each other between cord groups in which a plurality of cords are arranged in parallel to each other are used only for separation in a side region of the tire reinforcing material. It aims at suppressing the separation in the center area of the reinforcing material for tires, and improving the durability performance of the pneumatic tire using this reinforcing material for tires.

  The inventors of the above-described conventional tire reinforcing material repeat the tension and compression in the cord extending direction while suppressing the separation in the side section by increasing the cord restraining force between the cord groups. We studied how to reduce the heat generation generated in the central area by suppressing the separation in the central area. And the knowledge which it was effective to distinguish the center area and side part area of the reinforcing material for tires, and to optimize the structure of the laminated | stacked cord group came to complete this invention.

That is, the gist of the present invention is as follows.
(1) a plurality of code group that has been arranged parallel to one another code, and code group plural are arranged parallel to one another in the cords extending in a direction intersecting the chord extending direction of the code group is rubber coated The band-shaped body has a knitted structure in which cords are mistaken between the cord groups from both ends in the width direction of the belt-shaped body at both sides of 30% of the entire width of the belt-shaped body. A tire reinforcing material, characterized in that a central area continuously provided in a longitudinal direction of the body and sandwiched between both side areas has a laminated structure in which cords are stacked between the cord groups.

  (2) The tire reinforcing material according to (1), wherein both ends in the width direction have the braided structure.

  (3) The tire reinforcing material according to (1) or (2), wherein the width of the region of the braided structure is 1% or more of the total width.

  (4) The tire reinforcing material according to any one of (1) to (3), wherein a cord extending direction between the cord groups has a line-symmetric relationship with respect to the longitudinal direction.

  (5) A pneumatic tire using the tire reinforcing material according to any one of (1) to (4).

  According to the pneumatic tire of the present invention, a belt-shaped tire reinforcing material in which cords intersecting each other between cord groups in which a plurality of cords are arranged in parallel to each other is knitted. In addition to the separation at, the separation in the central region of the tire reinforcing material can also be suppressed, and as a result, the durability performance of the pneumatic tire using the tire reinforcing material can be improved.

It is a figure which shows a part of reinforcement material for tires according to this invention. It is a figure which expands and shows the center area and side part area of the reinforcing material for tires according to this invention. It is tire width direction sectional drawing represented about the tire half part of the pneumatic tire according to this invention. It is a figure which shows a part of conventional reinforcing material for tires.

  A part of the tire reinforcing material according to the present invention is shown in FIG. The tire reinforcing material according to the present invention is a belt-like body, and the belt-like body has a certain width and continuously extends in a direction orthogonal to the width direction (hereinafter referred to as “longitudinal direction”).

  As shown in FIG. 1, in the tire reinforcing material according to the present invention, a first cord group in which a plurality of cords are arranged in parallel to each other in a predetermined direction (represented by the x direction in FIG. 1), and the first cord This is a belt-like body formed by coating a rubber with a second cord group in which a plurality of cords extending in a direction crossing the cord extending direction of the group (represented by the y direction in FIG. 1) are arranged in parallel to each other (see FIG. 1 shows only the cord of the tire reinforcing material and omits the rubber display).

  Here, the first cord group and the second cord group are basically stacked, and the cords of both cord groups intersect when viewed in the stacking direction (the direction from the front to the back in FIG. 1). , Have an intersection.

FIG. 2 shows an enlarged view of the central area and the side area of the tire reinforcement shown in FIG. In this reinforcing material, the first cord group consisting of cords C _{1 to} C _m and the second cord group consisting of cords C ′ _{1 to} C ′ _n intersect each other. For example, the cord C ₃ of the first cord group is knitted (staggered) with the cords C ′ _{1 to} C ′ _{3 of} the second cord group vertically and alternately in the stacking direction, and the second cord Overlaid in the stacking direction with the group codes C ′ ₄ and C ′ ₅ .

Here, in the tire reinforcing material according to the present invention, an intersection generated by the intersection of the cord C _r of the first cord group and the cord C ′ _s of the second cord group is represented by P _rs . In addition, the vertical relationship of the cord group at a certain intersection and the vertical relationship in the stacking direction of the cord group at at least one of the other intersections formed by the cords forming the intersection are opposite to each other. In this case, this intersection is called a knitting point. An intersection other than the knitting point is referred to as a overlapping point.
For example, focusing on the intersection P _33, are located at the intersection P _33, code C ₃ of the first code group C _'3 stacking direction lower side of the second code group (verso side). The other intersections P ₃₁ , P ₃₂ , P ₃₄ , P ₃₅ , P ₁₃ , P ₂₃ , P ₄₃ formed by the code C ₃ of the first code group and the C ′ ₃ of the second code group forming the intersection P ₃₃ are formed. , P ₅₃ , the intersections adjacent to the intersection P ₃₃ are P ₃₂ , P ₃₄ , P ₂₃ , and P ₄₃ . Here, at the intersection P ₃₂ , the first code group C ₃ is located on the upper side (the front side in the drawing) of C ′ ₂ of the second code group, and at the intersection P ₃₄ , the first code group C ₃ is the second code group C ₃ . Located at the lower side of the cord group C ′ _{4 in} the laminating direction (the back side in the drawing), and at the intersection P ₂₃ , the first cord group C ₂ is on the upper side of the second cord group C ′ _{3 in} the laminating direction (the front side in the drawing). position, and the intersection P _43, the first code group C ₄ is positioned at the C _'3 stacking direction lower side of the second code group (verso side). That is, vertical relationship in the stacking direction of the code groups in the intersection P ₃₃ is the light of a vertical relationship in the stacking direction of the code groups in the intersection P _32, P _23, are reversed. Therefore, the intersection _{P 33} is a weaving point.
Similar to the above, the intersection P ₃₂ is a weaving point.
On the other hand, paying attention to the intersection P _34, it is located at the intersection P _34, code C ₃ of the first code group C _'4 in the lamination direction above the second code group (near side). The other intersections P ₃₁ , P ₃₂ , P ₃₃ , P ₃₅ , P ₁₄ , P ₂₄ , P ₄₄ formed by the code C ₃ of the first code group and the C ′ ₄ of the second code group forming the intersection P ₃₄ of, the intersection adjacent to the intersection _{P 34,} which is _{P 33, P 35, P 24} , P 44. Here, the intersection P _33, the first code group C ₃ located in C _'3 stacking direction lower side of the second code group (verso side), the intersection P _35, the first code group C ₃ first Located at the lower side (back side of the drawing) of C ′ ₅ of the second cord group, and at the intersection P ₂₄ , the first code group C ₂ is lower (the rear side of the page) of C ′ ₄ of the second code group. located in), the intersection P _44, the first code group C ₄ is positioned at the C _'4 stacking direction lower side of the second code group (verso side). That is, the vertical relationship in the stacking direction of the cord group at the intersection P ₃₄ is the same regardless of the vertical relationship in the stacking direction of the cord group at the intersections P ₃₃ , P ₃₅ , P ₂₄ , and P ₄₄ . Therefore, the point _{P 34} is a heavy match point.
According to the above definition, the intersections P ₁₃ , P ₂₂ , P ₃₁ , P ₁₄ formed by the codes C _{1 to} C ₅ of the first code group and the codes C ′ _{1 to} C ′ _{5 of} the second code group shown in FIG. , P ₂₃ , P ₃₂ , P ₁₅ , P ₂₄ , P ₃₃ , P ₄₂ , P ₂₅ , P ₃₄ , P ₄₃ , P ₃₅ , P ₄₄ , P ₅₃ , P ₁₃ , P ₂₂ , P ₃₁ , P _{53 14} , P ₂₃ , P ₃₂ , P ₁₅ , P ₂₄ , P ₃₃ , P ₄₂ , P ₃₄ are knitting points, and P ₂₅ , P ₄₃ , P ₃₅ , P ₄₄ , P ₅₃ are overlapping points. is there.

  In the tire reinforcing material according to the present invention, a structure having a knitting point is called a knitting structure, and a structure having a overlapping point is called a overlapping structure.

Moreover, in the tire reinforcing material according to the present invention, it is necessary that the both sides of the tire reinforcing material, which is a belt-like body, have knitting points continuously in the longitudinal direction, that is, a knitted structure is provided. Here, the side area of the tire reinforcing material refers to the entire width of the tire reinforcing material from both ends in the width direction of the tire reinforcing material (SE in the case of the tire reinforcing material according to the present invention shown in FIGS. 1 and 2). In FIG. 1 and FIG. 2, it refers to the area up to a position of 30% of the distance W).
As described above, by providing the braided structure in the both side regions of the tire reinforcing material, the binding force of the cords between the cord groups is increased in the both side regions, and shear strain is hardly generated. Therefore, when shearing distortion occurs, separation that occurs with the surrounding rubber starting from the end face of the cord having weak adhesive strength with the rubber is suppressed. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material can be improved.

Further, in the tire reinforcing material according to the present invention, the central area (CR in FIGS. 1 and 2) sandwiched between both side areas (SR in FIGS. 1 and 2) has overlapping points on the entire surface. That is, it is necessary to consist of overlapping structures.
In this way, by making the central area sandwiched between the two side areas of the tire reinforcing material to have a overlapping structure, in the central area, it is avoided that the cord has a corrugated shape that undulates in the stacking direction. be able to. Therefore, compared to conventional tire reinforcements that have overlapping structures over the entire surface including the central area, the input amount of tension in the direction of extension of the cord that occurs due to internal pressure filling and rolling for the tire Becomes smaller. Accordingly, the deformation of the rubber contained in the tire reinforcing material and the heat generation associated therewith are reduced, and the rubber becomes difficult to be oxidized, and as a result, hard to harden. And the fall of the durability of adhesion between rubber and a cord is controlled and it becomes difficult to produce the separation of a cord. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material of the present invention can be improved.

Here, in the tire reinforcing material according to the present invention, in the side section SR, the region closer to the center section side than the braided structure section provided in the side section SR also has a overlapping structure, that is, both side sections. It is preferable that all the regions sandwiched between the braided structures provided in the section SR have a overlapping structure.
In this way, by making the entire region sandwiched between the braided structures provided in the both side areas to have the overlapping structure, the cord tension generated in the entire tire reinforcing material is further reduced, and as a result The durability performance of the pneumatic tire using the tire reinforcing material of the invention can be further improved.

In the tire reinforcing material according to the present invention, it is preferable that both end portions in the width direction have a knitted structure. Specifically, in the tire reinforcing material according to the present invention shown in FIG. 2, for example, the intersection P ₃₁ formed by the cord C ₃ of the first cord group and the cords C ′ _{1 to} C ′ _{5 of} the second cord group, When attention is paid to P ₃₂ , P ₃₃ , P ₃₄ , and P ₃₅ , the intersection P ₃₁ closest to the width direction end SE is a knitting point. Similarly, for the other cords C ₁ (and C ₂ ) of the first cord group, the intersection P ₁₃ closest to the width direction end SE is a knitting point.
Thus, by making the width direction both ends have a braided structure, the cords can be constrained between the cord layers at the width direction ends of the tire reinforcing material. Therefore, when shear strain is generated in the tire reinforcing material, separation between the rubber and the cord, which is generated from the end surface of the cord having a weak adhesive force with the rubber, can be suppressed. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material can be further improved.

Furthermore, in the tire reinforcing material according to the present invention, it is preferable that the region of the braided structure continuously spreads inward in the width direction from both ends SE in the width direction. Specifically, in the tire reinforcing material according to the present invention shown in FIG. 2, for example, the intersection P ₃₁ formed by the cord C ₃ of the first cord group and the cords C ′ _{1 to} C ′ _{5 of} the second cord group, When paying attention to P ₃₂ , P ₃₃ , P ₃₄ , and P ₃₅ , the intersection P ₃₁ closest to the width direction end SE is a knitting point. Hereinafter, the knitting points P ₃₂ and P ₃₃ continue, The indentation points continue inward in the width direction from both ends SE in the width direction. Similarly, the other cords C ₁ (and C ₂ ) of the first cord group have the width of the knitting point from the intersections P ₁₃ to P ₁₅ (from P ₂₂ to P ₂₄ ) closest to the width direction end SE. Continuous in the direction. That is, the braided structure continuously spreads inward in the width direction from the width direction end SE.
In this way, the region of the braided structure is knitted until it reaches the widthwise end of the tire reinforcement in the side area of the tire reinforcement by allowing the region of the braided structure to continuously expand from the widthwise ends to the widthwise inside. Can be provided. Therefore, the cord restraint force between the cord layers in the side area of the tire reinforcing material becomes stronger, and when shear strain occurs in the tire reinforcing material, the starting point is the end surface of the cord with weak adhesive strength to rubber. The resulting separation between rubber and cord can be suppressed. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material can be further improved.

Here, in the tire reinforcing material according to the present invention, it is preferable that there are three or more knitting points in the width direction from both ends SE in the width direction of the tire reinforcing material. In the tire reinforcing material according to the present invention shown in FIG. 2, the intersections P ₃₁ and P ₃₂ between the cord C ₃ of the first cord group and the cords C ′ _{1 to} C ′ _{3 of} the second cord group knitted to the cord C _3. , three points P ₃₃ is a knitted point, also, is the same for other codes in the first code group. Therefore, in the tire reinforcing material of this example, there are three knitting points in the width direction from both ends SE in the width direction of the tire reinforcing material. In the tire reinforcing member according to the present invention shown in FIG. 2, although the weaving point P ₃₁ overlaps with the widthwise end SE of the reinforcing material for a tire, P ₃₁ is also included in the weaving point.
As described above, if three or more braiding points are provided in the width direction from the end portion of the tire reinforcing material, the cord restraining force between the cord groups in the side region of the tire reinforcing material can be increased. . Therefore, even when shear strain occurs in the tire reinforcing material, separation between the rubber and the cord in the side region of the tire reinforcing material can be suppressed. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material of the present invention can be improved. If there are two knitting points, the effect of increasing the binding force of the cords between the cord groups is not sufficient, and the above separation cannot be sufficiently suppressed.

Furthermore, in the tire reinforcing material according to the present invention, the width of the region of the braided structure is preferably 1% or more of the total width W of the tire reinforcing material. Here, the width of the region of the braided structure refers to the distance in the width direction between the cords located on both outer sides in the width direction, among the braided cords belonging to the same cord group. Specifically, in FIG. 2, the cord C ′ located on both outer sides in the width direction among the cords C ′ _{1 to} C ′ ₃ of the second cord group knitted with respect to the cord C ₃ of the first cord group. The width direction distance d between ₁ and C ′ ₃ is defined as the width of the region of the braided structure.
Here, if the width of the region of the braided structure is less than 1% of the total width of the tire reinforcing material, the size of the region of the braided structure is not sufficient, and in the side area of the tire reinforcing material. The effect of suppressing the separation between the rubber and the cord is not sufficient. Therefore, the durability performance of the pneumatic tire using the tire reinforcing material of the present invention cannot be sufficiently improved.

  Further, in the tire reinforcing material according to the present invention, the width of the braided structure region is more preferably 1 to 10% of the total width of the tire reinforcing material. The effect of setting the width of the region of the braided structure to less than 1% of the total width of the tire reinforcing material is the same as described above. If it exceeds 10%, the area of the braided structure increases in the side area, and in the side area of the tire reinforcing material, the cord lamination direction occurs due to internal pressure filling and rolling with respect to the tire. The input amount of tension and compression of the tire increases, and as a result, the improvement of the durability performance of the pneumatic tire using the tire reinforcing material of the present invention is suppressed.

In the tire reinforcing material according to the present invention, the cord extending direction (x direction in FIG. 2) of the first cord group and the cord extending direction (y direction in FIG. 2) of the second cord group are mutually long. It is preferable to have a line-symmetric relationship with respect to the direction. For example, in FIG. 2, the code C ₃ and the code C ₃ ′ are parallel to the longitudinal direction through a point P ₃₃ where the code C ₃ of the first code group and the code C ₃ ′ of the second code group intersect. With respect to the straight line L, the relationship is axisymmetric.
Thus, if the cord extending directions of the first and second cord groups have a line-symmetric relationship, the reinforcing effect of the tire reinforcing material can be obtained symmetrically with respect to the longitudinal direction of the tire reinforcing material. This is convenient when the reinforcing material is used for a pneumatic tire.
The tire reinforcing material of the present invention is not limited to the above configuration, and the cord extending directions of the first and second cord groups may not be in a line-symmetric relationship with respect to the longitudinal direction.

Here, the smaller angle (represented by θ in FIGS. 1 and 2) among the angles formed by the cords of the first cord group and the second cord group is 10 ° to 60 °. preferable.
If the angle is more than 60 °, the rigidity of the tire reinforcing material is lowered, so that the durability performance of the pneumatic tire using the tire reinforcing material of the present invention cannot be sufficiently improved. If the angle is less than 10 °, when the tire reinforcing material is cut in the width direction and used, the phenomenon that the cord escapes from the blade edge of the blade used for cutting tends to occur, and cutting becomes difficult. For this reason, there is an increased possibility of hindering the use of the tire reinforcing material.

  The pneumatic tire of the present invention includes, for example, a tread portion, a pair of sidewall portions extending inward in the tire radial direction from both side portions of the tread portion, and a bead portion extending inward in the tire radial direction from each sidewall portion. A pneumatic tire using the tire reinforcing material of the present invention described above for a pneumatic tire having a carcass extending in a toroidal shape and a belt disposed outward in the tire radial direction of the carcass.

FIG. 3 shows a pneumatic tire according to the present invention in which the tire reinforcing material according to the present invention is used for a belt. In the pneumatic tire 10 according to the present invention, the tire reinforcing material 1 according to the present invention is used as a belt on the tread 2 outward in the tire radial direction of the carcass 3. And the longitudinal direction of the reinforcing material 1 for tires according to this invention is provided so that the width direction may turn to the tire circumferential direction, and the belt of this pneumatic tire is formed.
Thus, since the pneumatic tire of the present invention uses the tire reinforcing material of the present invention, the effects of the tire reinforcing material of the present invention can be obtained, and the durability of the belt is improved. Therefore, the durability performance of the pneumatic tire can be improved.

  The pneumatic tire of the present invention is not limited to the pneumatic tire using the tire reinforcing material of the present invention as a belt, but includes the carcass itself or the reinforcing material of the belt, carcass or bead. Any pneumatic tire used as a member to which a tire reinforcing material can be applied is included. And the method of using the reinforcing material for tires as each member of a pneumatic tire is well-known to those skilled in the art.

Hereafter, the structural member of the reinforcing material for tires of this invention is explained in full detail.
As a cord used for the reinforcing material for tires of the present invention, for example, an organic fiber cord, an inorganic fiber cord, a metal fiber cord, or a combination thereof is used. Here, examples of the organic fiber cord include nylon fiber, aramid fiber, polyethylene terephthalate (PET) fiber and polyethylene naphthalate (PEN) fiber, polyamide fiber, polyparaphenylenebenzoxazole (PBO) fiber, polyketone (PK). ) Fibers, cellulose fibers such as rayon, carbon fibers, and the like, but are not particularly limited. In addition, examples of the inorganic fiber include a glass fiber cord and a metal fiber cord, for example, a steel cord, but are not particularly limited.

  Examples of rubber constituting the tire reinforcing material of the present invention include natural rubber (NR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), and polyisoprene rubber (IR). Although there is a typical rubber component, it is not particularly limited. And these rubber | gum is mix | blended and used for the compounding agent normally used in the rubber industry. Examples of the compounding agent include, but are not particularly limited to, carbon black, softener, zinc white, anti-aging agent, vulcanization accelerator and sulfur.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.

Example 1
A plurality of metal fiber cords (1 × 3 × 0.30 cord) were coated with coating rubber (natural rubber) and cut into a certain length. The coated cords were arranged on the cylindrical drum at a predetermined angle with respect to the circumferential direction and at a predetermined interval to form a first cord layer composed of a first cord group. Similarly, a second cord layer having a cord extension direction different from the cord extension direction of the cord layer was further formed on the first cord layer to produce a superimposed structure. At this time, the angle formed by the cord extending direction of the first cord layer and the cord extending direction of the second cord layer was 40 °. For the tire shown in FIGS. 1 and 2, the cord ends of the first and second cord groups are woven by hand, so that only the side area has a knitted structure, and the central area has a overlapping structure. A reinforcing material was produced. And the following durability evaluation was performed using this reinforcing material for tires.

(Conventional example 1)
Similar to the first embodiment, the first and second cord layers are formed, the overlap structure is formed, and then the entire surfaces of the first and second cord layers are knitted to have a knitted structure over the entire surface. An example tire reinforcement was created. And the following durability evaluation was performed using this reinforcing material for tires.

(Durability evaluation)
Using the tire reinforcing material of the present invention and the tire reinforcing material of the conventional example as belts, the pneumatic tires of the present invention and the conventional pneumatic tires of various tire sizes shown in Table 1 were produced. Each of the pneumatic tires was mounted on an applicable rim defined in JATMA standards, and the pneumatic tire was mounted on a passenger car under conditions of a predetermined internal pressure and a predetermined load (Table 1 shows the applicable rim, internal pressure and load). Show). And this passenger car was made to drive | work on the conditions shown in Table 1, and the running time until a pneumatic tire broke down was measured. The ratio (A / B) of the running time (A) until the pneumatic tire of the present invention failed with respect to the running time (B) until the pneumatic tire of the conventional example failed was calculated. It shows that the durability performance of the pneumatic tire which used the reinforcement cord layer of this invention for the belt is so high that this ratio is large.

(Examples 2 to 12, Comparative Example 1)
The durability evaluation was performed in the same manner as in Example 1 except that pneumatic tires having the specifications shown in Table 1 were used.

  By comparing Example 1 with Comparative Example 1, the durability of the pneumatic tire using the tire reinforcing material of the present invention for the belt is the same as the durability of the pneumatic tire using the conventional tire reinforcing material for the belt. The effect of the present invention is shown to be higher than the property. Moreover, it was shown by having compared the Example 1 and Examples 4, 5, 6, and 11 that it has a braided structure in the width direction edge part. Further, by comparing Example 3 with Examples 4, 5, 6, 7, 8, and 11, it was shown that the width of the region of the braided structure is preferably 1% or more of the entire width. And by comparing Example 3 with Examples 4, 5, 6, and 11, it was shown that the width of the region of the braided structure is particularly preferably 1% or more and 10% or less of the entire width. . Further, a comparison between Examples 4, 5, 6, and 11 and Example 12 shows that the cord extending direction is preferably line-symmetric with respect to the longitudinal direction between the cord groups. It was. By comparing Example 3 with Examples 4, 5, 6, 7, 8, and 11, it was shown that the number of knitting points is preferably 3 or more. By comparing Example 11 with Examples 9 and 10, it was shown that the angle formed by the cord group was preferably 10 ° to 60 °.

  According to the pneumatic tire of the present invention, a belt-shaped tire reinforcing material in which cords intersecting each other between cord groups in which a plurality of cords are arranged in parallel to each other is knitted. In addition to the separation at, the separation in the central region of the tire reinforcing material can also be suppressed, and as a result, the durability performance of the pneumatic tire using the tire reinforcing material can be improved.

DESCRIPTION OF SYMBOLS 1 Reinforcing material for tire 2 Tread 3 Carcass 10 Pneumatic tire d Width distance between cords C _{1 to} C _m Cords of first cord group C ′ _{1 to} C ′ _n Cords of second cord group CR Central area L Longitudinal direction Straight line P _rs intersection, braiding point, _overlapping point SE end of tire reinforcement in the width direction SR side area W full width of tire reinforcement

Claims (5)

Strip in which the code group has been arranged parallel to one another a plurality of codes, and code group plural are arranged parallel to one another in the cords extending in a direction intersecting the chord extending direction of the code group is rubber coated Because
In both sides of 30% of the entire width of the band from both ends in the width direction of the band, a braided structure in which the cords are mistaken between the cord groups is continuous in the longitudinal direction of the band. The tire reinforcing material is characterized in that a central area sandwiched between the both side areas has a stacked structure in which cords are stacked between the cord groups.   The tire reinforcing material according to claim 1, wherein both ends in the width direction have the braided structure.   The tire reinforcing material according to claim 1 or 2, wherein a width of the region of the knitted structure is 1% or more of the full width.   The tire reinforcing material according to any one of claims 1 to 3, wherein a cord extending direction between the cord groups has a line-symmetric relationship with respect to the longitudinal direction.   A pneumatic tire using the tire reinforcing material according to any one of claims 1 to 4.

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