JP2018103856A - Pneumatic tire and carcass ply member thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carcass ply member which makes improvements with respect to reduced rigidity caused by unevenly arranged cords in a side part and insufficient durability caused by separation occurring at a ply end, and also to provide a pneumatic tire with such a carcass ply member wound up inwardly from the outside in a tire width direction.SOLUTION: The present invention relates to a pneumatic tire, in which a carcass ply member 6 for the pneumatic tire is made up by covering with rubber two carcass cords 61 including a first carcass cord 70 and a second carcass cord 80, and the first carcass cord and the second carcass cord are arranged to go back and forth between both ends 60A, 60B of the carcass ply member in a lateral direction X1 for meandering in a longitudinal direction Y1, such that intersections 65 of the first carcass cord and the second carcass cord are disposed at an even interval in the longitudinal direction Y1 in a lateral central region C and folding back portions 72, 82, 74, 84 and the intersections 65 form rhombic regions E, F disposed adjacent to each other in the longitudinal direction Y1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a carcass ply member used for a pneumatic tire and a pneumatic tire using the same.

  In a pneumatic tire, a carcass ply as a reinforcing material embedded therein is generally configured to wind up from the inner side in the tire width direction to the outer side so as to wrap the bead core.

  On the other hand, in a pneumatic tire having a pair of left and right beads including a bead core and a carcass ply bridged between the pair of bead cores, the carcass ply surrounds the bead core from the outer side in the tire width direction to the tire width direction. A pneumatic tire having a configuration wound up inward has been proposed.

  With this configuration, the distribution of the tension applied to the carcass ply is changed, the tension at a position that easily contributes to the tire rigidity is increased, and the steering stability performance can be improved.

   However, the configuration in which the carcass ply is wound from the outer side in the tire width direction to the inner side is the winding in the direction in which the circumferential length is narrowed. It becomes a factor of a fall, or a separation arises in a winding end part, and becomes a factor which reduces durability.

  In the following Patent Document 1, a pneumatic tire having a configuration in which the carcass ply is wound inward from the outer side in the tire width direction by providing notches at a plurality of locations in the tire circumferential direction at the end of the rolled-up portion of the carcass ply. There is shown a pneumatic tire that suppresses generation of wrinkles during winding and has improved durability.

  However, in order to suppress the occurrence of wrinkles at the time of winding up and improve durability, notches are provided at a plurality of locations in the tire circumferential direction at the end of the winding up portion of the carcass ply. Processing is required.

  The following Patent Document 2 includes a tread portion, a sidewall portion, and a bead portion, and each bead reinforcement layer disposed in each bead portion and continuous in the circumferential direction, and toroidally between the bead reinforcement layers. A carcass ply that extends and reinforces each part described above, and the carcass ply is constituted by a continuous cord that sequentially repeats reciprocation between the respective bead reinforcement layers via a folded part positioned along the circumference of the bead part. In addition, by arranging two or more carcass plies and interposing a rubber sheet between the carcass plies, a bead portion is required under a carcass ply structure that facilitates automatic molding of green tires. Ensuring sufficient strength and rigidity to effectively prevent the carcass cord from being pulled out, increasing the bead durability A pneumatic radial tire was above is shown.

  The following Patent Document 3 includes a pair of bead cores, and a carcass ply in which the vicinity of one end in the width direction is folded by one bead core and the vicinity of the other end in the width direction is folded by the other bead core, The carcass ply includes one or more carcass cords that are folded back at both ends in the width direction and extend while meandering in the tire circumferential direction, and the number of turns of the carcass cord is at least two and the number of turns is different. The carcass cords cross each other in the vicinity of the widthwise end of the carcass ply, and the folded ends of the carcass cord are non-uniformly arranged in the tire radial direction at both ends in the widthwise direction of the carcass ply. Pneumatic tires that have high anchoring effects and that can ensure the rigidity of the bead without requiring additional members are shown. There.

  In Patent Document 4 below, in a pneumatic tire in which a belt is disposed between a tread and a carcass extending in a toroidal shape between both bead cores, the belt includes a reinforcing member and a covering rubber that covers the belt. And at least one layer of metal wire planar bundles in which a plurality of untwisted metal wires are arranged in a plane in the circumferential direction. In contrast, the metal linear surface is formed by turning the front and back of both sides of the belt ply and folding it back so that both sides of the belt ply are not thickened and are cut at both sides of the belt ply. A pneumatic tire is shown having a belt reinforced with an endless metal reinforcement.

  Patent Document 5 listed below is an intermediate material in which cords are arranged in a zigzag manner between extended bodies arranged side by side, and the extended body can be deformed in the longitudinal direction, and the cords are folded back. By having a configuration in which engagement portions are periodically provided in the longitudinal direction, and by engaging the cords in a zigzag manner between the engagement portions, it is possible to manufacture them in advance and store them until use. Used for intermediate materials that can significantly reduce the molding time of composite materials and can easily change the cord interval and cord angle during use, for example, the carcass layer (composite materials) of pneumatic tires The reinforcements to be made are shown.

  In the above Patent Documents 2 to 5, there is a decrease in rigidity due to uneven arrangement of the carcass cords in the side portion of the carcass ply and insufficient durability due to separation generated at the end of the carcass ply.

JP2015-105000A JP 2000-301912 A JP 2004-224072 A JP 2011-51451 A JP 2003-252006 A

  In view of the above points, the present invention provides a carcass ply member that has improved rigidity reduction due to uneven arrangement of carcass cords at the side portion of the carcass ply and insufficient durability due to separation occurring at the end of the carcass ply, and a carcass ply used for the carcass ply. An object of the present invention is to provide a pneumatic tire having a configuration in which a carcass ply is wound up from the outside in the tire width direction to the inside.

  Embodiment of this invention consists of a sheet | seat which has the longitudinal direction arrange | positioned along a tire circumferential direction first, and the horizontal direction arrange | positioned along a tire meridian direction, and is a 1st carcass cord and a 2nd carcass cord. In the carcass ply member for a pneumatic tire formed by covering two carcass cords with rubber, the first carcass cord is disposed while being inclined from one end side to the other end side in the lateral direction. The second carcass cord is arranged so as to meander in the longitudinal direction by reciprocating between both ends in the horizontal direction by repeating the arrangement while inclining toward the one end side after being folded in a curved shape at the end, The first carcass cord is arranged adjacent to the first carcass cord, is inclined while being inclined from one end portion in the lateral direction to the other end portion, and is bent back at the other end portion, and then to the one end portion. Repeat the arrangement while tilting. The sheet is arranged so as to meander in the longitudinal direction by reciprocating between both ends in the lateral direction by forming a crossing portion between the first carcass cord and the second carcass cord in the lateral central region of the seat. A region surrounded by a line connecting the folded portion of the first carcass cord, the folded portion of the second carcass cord facing the first carcass cord, and the adjacent intersecting portion of the first carcass cord and the second carcass cord. A carcass cord having a rhombus shape, and a first gap in the rhombic shape of the carcass cord having the rhombus shape, and a gap between the carcass cord having the rhombus shape adjacent to the carcass cord having the rhombus shape. The carcass plastic for a pneumatic tire is arranged such that the second interval in the vertical direction is such that the first interval on the same vertical direction line in the central region is larger than the second interval. In the member.

  Secondly, in the embodiment of the present invention, the carcass for a pneumatic tire is arranged such that the first interval on the same vertical line at a predetermined distance from the central region in the direction of the folded portion is larger than the second interval. Located on the ply member.

  The third embodiment of the present invention is a carcass ply member for a pneumatic tire that is arranged such that the first interval on the same vertical line is equal to or smaller than the second interval in the folded portion.

  Fourth, the embodiment of the present invention resides in a carcass ply member for a pneumatic tire that is disposed so that the first interval and the second interval on the same vertical line are equal in the folded portion.

  Fifth, the embodiment of the present invention includes a pair of left and right beads including a bead core and a carcass ply spanned between the pair of bead cores, and the carcass ply surrounds the pair of bead cores in the tire width direction. The pneumatic tire is wound from the outside to the inside in the tire width direction, and the carcass ply is in the pneumatic tire formed by the carcass ply member.

  According to the carcass ply member of the present embodiment, the rigidity reduction due to the uneven arrangement of the carcass cords at the side portion of the carcass ply and the lack of durability due to the separation generated at the end of the carcass ply are improved. Further, by using the carcass ply using the carcass ply member for a pneumatic tire having a configuration in which the carcass ply is wound from the outer side to the inner side in the tire width direction, a reduction in rigidity due to uneven arrangement of the carcass cords at the side portion of the carcass ply Durability deficiency due to separation at the edge is improved.

The half sectional view of the pneumatic tire concerning one embodiment. FIG. 2 is an enlarged sectional view around a bead portion in FIG. 1. The partial top view with a partial enlarged view which expressed typically the carcass ply member concerning one embodiment.

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

  The pneumatic tire T of the embodiment shown in FIG. 1 is a pneumatic radial tire for passenger cars, and includes a tread portion 1 that constitutes a ground contact surface and a pair of left and right side portions 2.

  The side portion 2 includes a bead portion 30 on the inner peripheral side in the tire radial direction, and a sidewall portion 20 interposed between the bead portion 30 and the tread portion 1. In the bead portion 30, a bead 33 including an annular bead core 31 made of a bead wire and a bead filler 32 joined and integrated on the outer peripheral surface of the bead core 31 is embedded. The bead filler 32 is made of hard rubber and has a triangular cross-section that is narrower toward the tip side.

  In the tire T, a carcass ply 4 is buried between a pair of left and right bead cores 31. The carcass ply 4 extends from the tread portion 1 to the side portions 2 on both sides, and both end portions thereof are wound and locked by the bead core 31. Therefore, the carcass ply 4 includes a toroid-shaped main body portion 41 straddling between the pair of bead cores 31 and a winding portion 42 wound around the bead core 31 at both end portions of the main body portion 41. The carcass ply 4 is formed by covering the carcass cord with rubber and disposed so that the carcass cord is substantially perpendicular to the tire circumferential direction. In this example, the carcass ply 4 has a single-layer structure including one ply. .

  As shown in FIG. 2, both ends of the carcass ply 4 are wound around the bead core 31 from the outside in the tire width direction X to the inside through the tire outer surface side of the bead filler 32, that is, turned up. . The winding portion 42 extends outward in the tire radial direction Y inside the tire 33 in the tire width direction X of the bead 33. In this example, a winding end portion (outer end portion in the tire radial direction Y) 43 that is an end portion of the winding portion 42 extends beyond the outer peripheral surface 31A of the bead core 31 to the bead filler 32. The bead filler 32 is terminated at the inner side in the tire radial direction Y from the outer end 32A in the tire radial direction Y.

  An inner liner 5 is provided as a gas barrier rubber layer on the inner surface of the tire. The inner liner 5 is disposed on the inner peripheral side of the carcass ply 4. Both ends of the inner liner 5 are wound around the bead core 31 from the inner side to the outer side in the tire width direction X. Both end portions of the inner liner 5 extend between the bead core 31 and the carcass ply 4 around the bead core 31.

  As shown in FIG. 1, a belt 11 is disposed on the outer peripheral side of the carcass ply 4 in the tread portion 1. The belt 11 is composed of one or a plurality of belt layers in which a belt cord is inclined at a constant angle with respect to the tire circumferential direction. In this example, the belt 11 is composed of two belt layers. A tread rubber 13 is provided on the outer peripheral side of the belt 11 via a belt reinforcing layer 12.

  Sidewall rubber 21 is provided on the tire outer surface side of the carcass ply 4 in the sidewall portion 20. The bead portion 30 is provided with a rubber chacher 34 around the bead core 31 so as to cover the carcass ply 4 and the inner liner 5.

  The structure of the carcass ply member 6 forming the carcass ply 4 is shown in FIG. The carcass ply member 6 has a longitudinal direction Y1 disposed along the tire circumferential direction and a seat 60 having a lateral direction X1 disposed along the tire meridian direction (a direction perpendicular to the tire circumferential direction on the tire surface). This is a belt-like member having the horizontal direction X1 as the width direction and the vertical direction Y1 as the length direction. The carcass ply member 6 is provided with a carcass cord 61 having two configurations of a first carcass cord 70 and a second carcass cord 80. In this embodiment, the driving density of the carcass cord 61 is 30 in one inch. Of course, the driving density may be slightly increased or decreased. The carcass cord 61 is made of, for example, an organic fiber cord, and is covered with unvulcanized rubber, and is embedded in a sheet 60 made of unvulcanized rubber to constitute the carcass ply member 6.

  The first carcass cord 70 and the second carcass cord 80 constituting the carcass cord 61 are constituted by continuous cords that reciprocate while being folded at both lateral end portions 60A and 60B of the seat 60 and extend in the longitudinal direction Y1.

  That is, the first carcass cord 70 extends in a straight line while being inclined toward the other end 60B from one end 60A in the lateral direction X1 of the seat 60 (in the drawing, to the lower left). , And after passing through the folded-back portion 72 that is folded back at the other end 60B, the side extends linearly while being inclined (downward to the right in the drawing) from the other end 60B toward the one end 60A. A folded portion 74 that is bent in a curved shape is formed at one end 60A via the direction extending portion 73, and by repeating this, it is arranged so as to meander between the both ends 60A and 60B in the lateral direction X1 in the longitudinal direction Y1. Has been.

  On the other hand, the second carcass cord 80 is arranged adjacent to the first carcass cord 70 and symmetrically with the first carcass cord 70, and is arranged from the other end 60 </ b> B in the lateral direction X <b> 1 of the seat 60 to the one end 60 </ b> A. After passing through a laterally extending portion 81 that extends in a straight line while being inclined toward the right (downward in the drawing in the figure), through a folded portion 82 that is bent back at one end 60A, the other end 60A A folded portion 84 is formed that is folded in a curved shape at one end 60B via a laterally extending portion 83 that extends in a straight line while being inclined from the first end 60B toward the left end 60B. Is repeated so as to meander between the two end portions 60A and 60B in the horizontal direction X1 in the vertical direction Y1.

  Therefore, the first and second carcass cords 70, 80 have their folded portions 74, 82 (60A side), 72, 84 (60B side) along the longitudinal direction Y1 in the end region P in the lateral direction X1 of the sheet 60. The folded portions 72, 74, 82, 84 are each formed in a curved shape by an arc, and in this example, have a semicircular shape. Further, the first and second carcass cords 70 and 80 intersect each other in the central region C in the lateral direction X1 of the seat 60 so that the intersecting portions 65 are formed at equal intervals in the longitudinal direction Y1.

  Then, the folded portion 72 of the first carcass cord 70, the folded portion 82 of the second carcass cord 80 facing the first folded portion 70, and the upper and lower intersecting portions 65 adjacent to each other between the first carcass cord 70 and the second carcass cord 80 are connected. The region E surrounded by the line is configured to have a rhombus shape (in the figure, a horizontally long rhombus shape), and similarly, the folded portion 74 of the first carcass cord 70 and the folded portion 84 of the second carcass cord 80 facing each other. A region F surrounded by a line connecting the adjacent upper and lower intersecting portions 65 of the first carcass cord 70 and the second carcass cord 80 is configured to form a rhombus shape (a horizontally long rhombus shape in the figure). The shape regions E and F are alternately arranged in parallel in the vertical direction Y1.

  With respect to the interval between the carcass cords, the first interval A in the longitudinal direction in the rhombus shape of the carcass cord 61 having a rhombus shape and the vertical distance in the gap between the carcass cord 61 having a rhombus shape adjacent to the carcass cord 61 having the rhombus shape. The second interval B in the direction is arranged so that the first interval A on the same vertical line in the central region C is larger than the second interval B. Further, the first interval A on the same vertical direction line in the left and right intermediate portion D at a predetermined distance from the central region C in the direction of the folded portions 72, 74, 82, 84 is arranged to be larger than the second interval B. Furthermore, in the folding | returning parts 72, 74, 82, 84, it arrange | positions so that the 1st space | interval A and the 2nd space | interval B on the same vertical direction line may become equal. Note that the first interval A on the same vertical line in the folded portions 72, 74, 82, 84 may be arranged smaller than the second interval B. In this state, the rubber coating is performed to form an integrated carcass cord as a whole, and the intersection portion 65 is formed as an integrated carcass cord by being rubber-coated in a state where the cords are crossed.

  In the tire T of the present embodiment, the carcass cord 4 has the center region C of the carcass ply member 6 disposed in the tread portion 1 in FIG. 1, and the left and right intermediate portion D is the side portion 2 including the shoulder portion 14 and the sidewall portion 20. The bead core portion BC included in the left and right intermediate portion D is disposed around the bead core 31, and both end region P forms a winding portion 42 in which the carcass cord 4 is wound from the outside in the tire width direction X to the inside. It will be. In this bead core portion BC, it is appropriate that the first interval A is 1.0 to 2.0 times the second interval B.

  The manufacturing method of the pneumatic tire T according to the present embodiment can be manufactured by a known method except that the carcass ply member 6 is used as the carcass ply member that forms the carcass ply 4. For example, as disclosed in Japanese Patent Application Laid-Open No. 2014-125120, the inner liner 5 is attached on the tire molding drum, the bead 33 is placed on the inner liner 5, and the carcass ply member 6 is attached thereon. After attaching the side wall rubber 21 and the like, both ends of the carcass ply member 6 are folded back to the inner peripheral side of the bead 33 to produce a primary molded body. At this time, the carcass ply member 6 may be attached on the inner liner 5 with the longitudinal direction Y1 being disposed in the tire circumferential direction and the lateral direction X1 being in the tire meridian direction. Thereafter, the primary molded body is expanded in the radial direction, and then the belt 11 and the tread rubber 13 are attached, and then both end portions of the carcass ply member 6 are wound up inside the bead 33 and pressed. A pneumatic tire T is obtained by vulcanization molding of the green tire thus obtained.

  According to the present embodiment as described above, the carcass ply 4 has a structure in which both ends thereof are wound around the bead core 31 from the outside in the tire width direction X to the inside through the tire outer surface side of the bead filler 32. In the tire T, the carcass ply 4 is formed by arranging the two first carcass cords 70 and the second carcass cords 80, and the first carcass cords 70 and the second carcass cords 80 are respectively arranged at both lateral ends of the seat 60. The following functions and effects are exhibited by configuring the cords to be continuous while being bent at 60A and 60B and arranging the first carcass cord 70 and the second carcass cord 80 in a rhombus shape.

(1) Because of the two configuration, it becomes uniform in the tire width direction and contributes to improving rigidity by making the tension distribution uniform.

(2) The tread portion 1 in which the central region C of the carcass ply 4 is located, and the side located in the left and right intermediate portion D at a predetermined distance from the central region C of the carcass ply 4 in the direction of the folded portions 72, 74, 82, 84. Since the intervals A and B of the carcass cord 61 in the portion 2 change, it is possible to secure rigidity while reducing the weight.

(3) Since the carcass cord 61 in the side portion 2 is inclined and disposed along the peripheral surface of the side portion, the rigidity in the tire circumferential direction is improved.

(4) Since the carcass ply 4 has a structure in which the carcass ply 4 is wound from the outside in the tire width direction X to the inside, the carcass cords 61 of the side portions 2 come close. By increasing the distance between the carcass cords 61 of the side portions 2, the rigidity is improved. In this case, normally, the carcass ply in the carcass ply becomes too dense, so that wrinkles occur at the winding end 43 and some carcass cords do not contribute to the rigidity of the winding end 43, but the durability deteriorates. In the aspect, since the generation of wrinkles is prevented by providing a gap between the carcass cords 61 at the winding end portion 43, since the gaps of the carcass cords 61 are uniform, all the carcass cords 61 contribute to rigidity and are durable. The force can be improved, and the number of carcass cords 61 can be reduced to reduce the weight.

  Further, since the first interval A and the second interval B of the carcass cord 61 are arranged around the bead core 31 so that the first interval A is larger than the second interval B, the carcass ply 4 is arranged in the tire width. By winding up from the outer side in the direction X to the inner side of the carcass ply 4 from the tread part 1 where the carcass ply 4 is located to the bead part 30, the carcass cord gradually becomes dense and the bead part from the shoulder part 14 is utilized. The rigidity distribution can be changed by gradually increasing the density of the carcass cord 61 over 30. In the bead core portion BC, it is appropriate that the first interval A of the carcass cord 61 is disposed at intervals of 2.0 times or less exceeding 1.0 of the second interval B, and the following both end portions from the bead core portion BC. Durability can be ensured by providing an interval to the region P.

  In both end region P of the carcass ply 4 in the lateral direction X1, since the first interval A and the second interval B of the carcass cord 61 are arranged to be equal to each other, the carcass ply 4 is arranged outside the tire width direction X. Can be prevented from being wrinkled due to the distance between the carcass cords 61 when being wound inwardly from the inner side, the separation of the end of the carcass ply 4 can be suppressed by providing a certain distance, and the carcass at the end of the carcass ply 4 can be suppressed. By making the intervals of the cords 61 the same, the arrangement of the carcass cords 61 can be made uniform.

  In the central region C of the carcass ply 4, the first interval A and the second interval B of the carcass cord 61 are arranged such that the first interval A is larger than the second interval B, and the carcass ply intersects the carcass cord 61. 4, the second interval B of the carcass cord 61 is arranged to be 0 at the center in the lateral direction X1. Therefore, in the tread portion 1 where the steel belt is arranged on the belt 11, the carcass is added in consideration of the rigidity of the steel belt. The density of the cord 61 can be reduced and weight reduction can be achieved, and durability can be ensured by arranging the intersecting portion 65 of the carcass cord 61 in the tread portion 1 where the fluctuation of the lower portion of the belt 11 in the tire T is small. .

  In order to show the effect of the above embodiment, pneumatic radial tires for passenger cars (size: 195 / 65R15) of Example 1 and Comparative Examples 1 and 2 were prototyped.

  The tire of Example 1 is the tire of the embodiment shown in FIGS.

  The tire of Comparative Example 1 uses a single carcass ply member in which a large number of carcass cords are aligned in parallel (having cord cut ends at both lateral ends) (carcass cord driving density = 30/25 mm), the tire having a structure in which the carcass ply member is wound around the bead core from the inner side to the outer side in the tire width direction.

  The tire of Comparative Example 2 is a tire having a structure in which a carcass ply member similar to that of Comparative Example 1 is wound up from the outside in the tire width direction to the inside around the bead core, as in Example 1. In each example, the other configurations are the same.

  For each of these tires, steering stability, durability, longitudinal rigidity and lateral rigidity were evaluated. Each evaluation method is as follows.

  -Steering stability: The driver performed sensory evaluation of steering stability on a dry road by running a test vehicle (domestic 2L sedan) equipped with each tire at a speed of 100km / h. Evaluation was made with an index of 100. The larger the index, the better the steering stability.

  Durability: Durability test was performed with a drum tester according to the test method stipulated in the US automobile safety standard FMVSS139, the mileage until the tire failed was measured, and the measurement result of Comparative Example 1 was set to 100 Evaluated by index. The larger the index, the better the durability.

  ・ Longitudinal rigidity: Using a 50t stiffness tester, a tire is assembled to a rim of 15x6.5J at a pressure of 220 kPa on a 50t stiffness tester, and a longitudinal load is between 4.2kN ± 490N with a camber angle of 0 °. The amount of vertical deflection in the vertical direction when increasing or decreasing the load in the vertical direction was measured, and a value obtained by dividing the increased or decreased load amount by the amount of vertical deflection was calculated. The evaluation results are expressed as an index with the result of Comparative Example 1 being 100, and the larger the index, the higher the longitudinal rigidity.

  -Lateral stiffness: Using a 50-t stiffness tester, with a tire internal pressure of 220 kPa and a rim of 15X6.5-J applied with a longitudinal load of 4.2 kPa, further 30% of the longitudinal load was applied to the tire in the lateral direction. The amount of lateral deflection was measured by loading as a force, and a value obtained by dividing the lateral force by the amount of lateral deflection was created. The evaluation result is expressed as an index with the measurement result of Comparative Example 1 as 100, and the larger the index, the higher the lateral rigidity.

結果は、表１に示す通りである。比較例１に対し、カーカスプライの巻き上げ構造をタイヤ幅方向外側から内側の巻き上げに変更した比較例２では、操縦安定性は向上したものの、巻き上げ部に皺が入り、コード間隔が不均等になったことにより、耐久性に劣っており、また、縦横剛性の向上効果も小さいものであった。これに対し、実施例１では、カーカスプライをタイヤ幅方向外側から内側に巻き上げた構成において、２本の連続したカーカスコードを交差部を設けて配し、該交差部が中央領域に位置するように配したことにより、耐久性を向上することができ、また、縦剛性及び横剛性が向上して、操縦安定性が顕著に改善されていた。

The results are as shown in Table 1. In Comparative Example 2 in which the winding structure of the carcass ply is changed from the outer side in the tire width direction to the inner side in comparison with Comparative Example 1, the steering stability is improved, but the winding portion is wrinkled and the cord interval becomes uneven. As a result, the durability was inferior, and the effect of improving the longitudinal and lateral rigidity was small. On the other hand, in Example 1, in a configuration in which the carcass ply is wound up from the outer side in the tire width direction, two continuous carcass cords are provided with an intersecting portion so that the intersecting portion is located in the central region. As a result, the durability can be improved, and the longitudinal rigidity and the lateral rigidity are improved, and the steering stability is remarkably improved.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

T: Pneumatic tire, 1 ... tread portion, 2 ... side portion, 4 ... carcass ply, 5 ... inner liner, 6 ... carcass ply member, 11 ... belt, 12 ... belt reinforcing layer, 13 ... tread rubber, 14 ... Shoulder part, 20 ... side wall part, 21 ... side wall rubber, 30 ... bead part, 31 ... bead core, 31A ... outer peripheral surface of bead core, 32 ... bead filler, 32A ... radially outer end, 33 ... bead, 34 ... Rubber chacher, 41 ... carcass ply main body, 42 ... winding part, 43 ... winding end part, 60 ... sheet, 60A, 60B ... lateral end part of sheet, 61 ... carcass cord, 65 ... crossing part, 70 ... First carcass cord, 71, 73 ... laterally extending portion, 72, 74 ... folded portion, 80 ... second carcass cord, 81, 83 ... laterally extending portion 82, 84 ... folded portion, X ... tire width direction, Y ... tire radial direction, X1 ... lateral direction, Y1 ... longitudinal direction, C ... central region, BC ... bead core portion, P ... both end regions, D ... left and right intermediate portions , E, F ... diamond-shaped region, A ... first interval, B ... second interval,

Claims (5)

It consists of a sheet having a longitudinal direction arranged along the tire circumferential direction and a transverse direction arranged along the tire meridian direction, and the two carcass cords of the first carcass cord and the second carcass cord are covered with rubber. In the carcass ply member for a pneumatic tire,
The first carcass cord is repeatedly arranged such that the first carcass cord is inclined while being inclined from one end portion side in the lateral direction to the other end portion, folded back at the other end portion, and then inclined while being inclined toward the one end portion side. By arranging so as to meander in the vertical direction by reciprocating between both ends in the horizontal direction,
The second carcass cord is disposed adjacent to the first carcass cord, and is disposed while being inclined from one end portion in the horizontal direction to the other end portion, and is bent in a curved shape at the other end portion. After that, it is arranged so as to meander in the vertical direction by reciprocating between both ends in the horizontal direction by repeating the arrangement while inclining to one end.
Forming a crossing portion of the first carcass cord and the second carcass cord in a lateral central region of the seat;
A region surrounded by a line connecting the folded portion of the first carcass cord, the folded portion of the second carcass code facing the first carcass cord, and the adjacent intersection of the first carcass cord and the second carcass cord is rhombus-shaped Configured to make
A first vertical interval in the rhombus shape of the rhombus-shaped carcass cord and a second vertical interval in the gap between the rhombus-shaped carcass cord adjacent to the rhombus-shaped carcass cord. The carcass ply member for a pneumatic tire is arranged such that the first interval on the same vertical line in the central region is larger than the second interval. The carcass for a pneumatic tire according to claim 1, wherein the first interval on the same vertical line at a predetermined distance from the central region in the direction of the turned-up portion is larger than the second interval. Ply member. The carcass ply member for a pneumatic tire according to claim 1 or 2, wherein the folded portion is arranged such that the first interval on the same vertical line is equal to or smaller than the second interval. The carcass ply member for a pneumatic tire according to any one of claims 1 to 3, wherein the folded portion is disposed so that the first interval and the second interval on the same vertical line are equal. . A pair of left and right beads including a bead core, and a carcass ply spanned between the pair of bead cores, the carcass ply being wound around the pair of bead cores from the outer side in the tire width direction to the inner side in the tire width direction. A pneumatic tire,
A pneumatic tire, wherein the carcass ply is formed of the carcass ply member according to claim 1.

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