JP2006188017A - Method for producing reinforcing member for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity by preventing the entrance of air and the confusion of cords with regard to the production of a reinforcing member which can make durability during runflat traveling and riding comfortableness performance coexistent when used in a pneumatic radial tire, especially a runflat tire. <P>SOLUTION: The reinforcing member 16 is constituted by arranging reinforcing member elements 14 obtained by cutting at least one cord 10, after being coated with a rubber, in a prescribed length to make its longitudinal direction be inclined to the arrangement direction and arranging the reinforcing member elements so that the closest cord interval WC between the adjacent reinforcing member elements 14 is 2-10 times in relation to the diameter W of the cord. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a tire reinforcing member used for a sidewall portion of a tire or the like.

  In small pneumatic radial tires that are mounted on vehicles with large mass and are used in a high deflection state exceeding 25% even during normal use, and pneumatic radial tires that are used under special usage conditions (for example, run-flat tires) In order to improve the durability of the bead portion, a reinforcing layer having a metal or organic fiber cord is disposed on the bead portion or the sidewall portion.

The arrangement location is, for example, on the inner side or the outer side of the carcass ply in the tire axial direction, and when the carcass ply is wound up at the bead portion and has the turned-up portion, on the inner side or the outer side of the turned-up portion in the tire axial direction. Yes (see Patent Document 1).
Japanese Patent Laid-Open No. 11-334326

  However, the reinforcing layer having the organic fiber cord cannot secure the rigidity for the increase in thickness, and the reinforcing layer having the metal cord can secure the rigidity. There was a problem that a failure occurred from the part.

  Even if sufficient bead rigidity and durability can be ensured, a pneumatic radial tire having such a structure generally has poor vibration absorption during running and poor ride comfort performance. It was.

  As a result of studying the above problems by the inventors of the present application, the tire in the high deflection state has a large amount of shear deformation in the tire circumferential direction due to the sidewall portion bulging greatly in the tire width direction as the bead portion collapses, In particular, it has been found that the tire circumferential shear deformation concentrates on the end portion of the high-rigidity reinforcing layer in the bead portion, leading to failure at an early stage.

  Therefore, in order to suppress the deformation due to the bead portion falling, rigidity in the tire radial direction is required, but the rigidity against circumferential shear needs to be suppressed to some extent.

  Therefore, a treat (reinforcing member) in which steel cords are arranged at wider intervals and covered with rubber was devised, and when used in a pneumatic radial tire used in a high deflection state, ride comfort and durability are improved. It is effective to make it compatible, but because the distance between steel cords is several times the cord diameter and is very sparse, when trying to manufacture with the conventional calendar method using a comb roll and a rolling roll, Before rolling, the rubber was in close contact with the air, and it was difficult to control the tension for each steel cord, resulting in disturbance. Furthermore, since the rubber part is wide, there is a problem that it is easily distorted and it is difficult to perform a cutting operation.

  In consideration of the above facts, the present invention provides a reinforcing member capable of achieving both durability during run-flat running and riding comfort during normal use when used in a pneumatic radial tire, particularly a run-flat tire. The purpose of manufacturing is to prevent air entry and cord disturbance and improve productivity.

  According to the first aspect of the present invention, the reinforcing member elements having a predetermined length in which at least one cord is covered with unvulcanized rubber are arranged such that the longitudinal direction thereof is inclined with respect to the arranging direction, and at this time, adjacent to each other The reinforcing member elements are arranged such that the closest cord interval between the reinforcing member elements is 2 to 10 times the diameter of the cord, and the reinforcing member elements are joined together to form a reinforcing member.

  Here, the lower limit of the distance between the nearest cords is set to twice the diameter of the cord because the crack generated from the end portion of the cord as a reinforcing material propagates between adjacent cords along the cord. This is because, as the distance between cords (closest cord distance) becomes narrower, the crack growth speed becomes faster, and in the case of a tire used for high deflection, the distance between the cords becomes narrower and the rigidity becomes higher. This is because the stress and strain are concentrated at the end of the cord, and the initial cracking is accelerated.

  The reason why the upper limit is set to 10 times the diameter of the cord is that if the nearest cord interval is too wide, the rigidity of the reinforcing member is reduced and the durability improving effect is lost.

  In the method for manufacturing a tire reinforcing member according to claim 1, at least one (for example, several) cords are rubber-coated by an insulation method to manufacture a reinforcing member element, which is inclined with respect to the arrangement direction. A reinforcing member can be manufactured by arranging in a state.

  According to this manufacturing method, it is possible to manufacture a reinforcing member without causing a problem in the case of manufacturing by a calendar method, and by using the reinforcing member for reinforcing a sidewall portion of a run flat tire, for example, run flat running It is possible to achieve both durability during riding and ride comfort during normal driving.

  According to a second aspect of the present invention, in the method for manufacturing a tire reinforcing member according to the first aspect, the amount of the unvulcanized rubber in the radial direction of the cord is greater in the width direction than in the thickness direction of the reinforcing member element. The reinforcing member elements are formed so as to increase in number, and the adjacent reinforcing member elements are joined at the rubber portion at the end in the width direction.

  In the manufacturing method of the tire reinforcing member according to claim 2, since the adjacent reinforcing member elements are joined at the rubber portion at the end in the width direction, the treat-like reinforcing member is the same as that manufactured by the calendar method. It can be.

  According to a third aspect of the present invention, in the method for manufacturing a tire reinforcing member according to the first or second aspect, the reinforcing member element is disposed on a rubber sheet.

  In the method for manufacturing a tire reinforcing member according to claim 3, for example, a reinforcing member element can be directly disposed on a sidewall portion at the time of a raw tire in a manufacturing process of a run flat tire to form a reinforcing member. It is possible to manufacture a run-flat tire having both durability at the time and ride comfort performance during normal use.

  According to a fourth aspect of the present invention, in the method for manufacturing a reinforcing member for a tire according to any one of the first to third aspects, a bead core and a carcass are assembled on a cylindrical former to form a green case. The reinforcing member element is arranged in the structure.

  In the method for manufacturing a tire reinforcing member according to claim 4, for example, by arranging the reinforcing member elements directly on the outer peripheral surface of the green case before expansion or on the side wall surface of the green case after expansion, A reinforcing member (reinforcing layer) that performs reinforcement can be easily configured.

  As described above, according to the method for manufacturing a tire reinforcing member of the present invention, when used in a pneumatic radial tire, particularly a run-flat tire, durability during run-flat travel and ride comfort performance during normal use are achieved. With respect to the manufacture of a reinforcing member that can be made compatible, there is an excellent effect that air entry and cord disturbance can be prevented and productivity can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the method for manufacturing a tire reinforcing member according to the present embodiment, first, at least one (1 in FIG. 1, 2 in FIG. 2, 3 in FIG. 3, 4 in FIG. 4) is obtained by an insulation method. After the steel cords 10 are aligned substantially in parallel, the unvulcanized rubber 12 is coated while the cords 10 are pulled out, and then cut into a predetermined length to obtain a strip-shaped reinforcing member element 14.

  Specifically, the cord 10 is passed through a base (not shown), and at the same time, the unvulcanized rubber 12 is extruded together, and the cord 10 is embedded by pressing the unvulcanized rubber 12.

  The reinforcing member element 14 is formed so that the amount of the unvulcanized rubber 12 in the radial direction of the cord is larger in the width direction than in the thickness direction of the reinforcing member element 14.

  Then, as shown in FIG. 5, the reinforcing member elements 14 are arranged so as to be inclined with respect to a predetermined arrangement direction. At this time, the nearest cord interval WC between the adjacent reinforcing member elements 14 is the diameter W of the cord 10. The reinforcing member element 14 is disposed so as to be 2 to 10 times the size of the reinforcing member element 14 and further joined at the rubber portion of the end portion 14A in the width direction to constitute a treat-like reinforcing member 16.

  As shown in FIGS. 2 to 4, when a plurality of cords 10 are used in one reinforcing member element 14, the interval WI between the cords 10 in each reinforcing member element 14 is also different from that of the cord 10. It is desirable that the diameter is 2 to 10 times the diameter W. This is because the arrangement density of the cords 10 is sparse, which is advantageous in terms of riding comfort.

  As shown in FIG. 4, two cords 10 may be used as a pair of cord pairs, and the interval WI between adjacent cord pairs may be 2 to 10 times the diameter W of the cord 10. In this case, the code interval in the code pair may be narrow.

  As shown in FIG. 1, when the reinforcing member element 14 is flattened with a rectangular cross section, the end portions 14A in the width direction of the adjacent reinforcing member elements 14 are butt-joined.

  As shown in FIGS. 2 to 4, when the thickness of the reinforcing member element 14 is gradually reduced toward the width direction end portion 14A, the adjacent width direction end portions 14A are slightly overlapped with each other. You may join.

  As shown in FIG. 5, when manufacturing the reinforcing member 16, the reinforcing member element 14 may be disposed on a planar rubber sheet 18, for example. Further, as shown in FIG. 6, a bead core and a carcass (not shown) are assembled on a cylindrical former to form a green case 20, and the reinforcing member element 14 is directly disposed on the outer peripheral surface of the green case 20 before expansion. Or you may make it reinforce a bead part, for example by arrange | positioning the reinforcement member element 14 directly to the side wall surface (not shown) of the green case after expansion.

  In addition to this, it may be arranged on a certain table, or may be arranged on a cloth liner, a resin sheet or the like and wound up as it is.

  The method of disposing on the rubber sheet 18 is effective, for example, when reinforcing a sidewall portion (not shown) of a pneumatic radial tire, and the method of disposing it on the green case 20 is, for example, a bead portion of a pneumatic radial tire. This is effective when the reinforcement is performed.

According to the method for manufacturing a reinforcing member for a tire according to the present embodiment, the problem in the case of the calendar method can be solved, and the reinforcing member manufactured by the method is used for a pneumatic radial tire, particularly a run flat tire. Thus, it is possible to achieve both durability during run-flat driving and ride comfort performance during normal use.
(Test example)
Under the conditions shown in Tables 1 and 2, a reinforcing member according to the conventional manufacturing method (Conventional Example 1 to Conventional Example 6) and a reinforcing member according to the manufacturing method of the present application (Example 1 to Example 4) are manufactured, and workmanship and workability are improved. Compared. All cords are steel.

  The conventional manufacturing method is a so-called calendar type manufacturing method in which cords drawn from a plurality of reels are arranged in parallel through comb teeth and slits, and then a cord is embedded by pressing a rubber sheet with a rolling roll or the like.

  The manufacturing method of the present application is a so-called insulation method in which a cord is passed through a base and rubber is extruded together, and the rubber is crimped to embed the cord.

  FIG. 1 corresponds to the first embodiment, FIG. 2 corresponds to the second embodiment, FIG. 3 corresponds to the third embodiment, and FIG. 4 corresponds to the fourth embodiment.

  The code interval variation is a percentage display of the difference between the maximum value and the minimum value of the code interval in the actually manufactured reinforcing member with respect to the designed average code interval.

  According to this test example, both the code interval variation and the air entering area are large in the conventional example, and the cutting workability is various from impossible to excellent, but in the example, the code interval variation and the air entering area are small. The cutting workability is all excellent.

  As described above, the manufacturing method of the present application has higher accuracy of the code interval than the conventional manufacturing method, and has a small air-filled area that causes defects. Moreover, since the shape and rigidity brought into the cutting are appropriate, the workability is excellent, and the superiority as a manufacturing method is high.

It is a perspective view which shows a reinforcement member. It is a perspective view which shows a reinforcement member. It is a perspective view which shows a reinforcement member. It is a perspective view which shows a reinforcement member. It is a top view of the reinforcement member arrange | positioned on a rubber sheet. It is a perspective view of the reinforcement member arrange | positioned at the green case.

Explanation of symbols

10 Code 12 Unvulcanized rubber 14 Reinforcing member element 14A End in width direction 16 Reinforcing member 18 Rubber sheet 20 Green case

Claims (4)

  Reinforcing member elements having a predetermined length, in which at least one cord is covered with unvulcanized rubber, are arranged so that the longitudinal direction thereof is inclined with respect to the arranging direction, and at this time, the most recent reinforcing member elements between adjacent reinforcing member elements are arranged. A method of manufacturing a tire reinforcing member, wherein the reinforcing member elements are arranged so that a contact cord interval is 2 to 10 times as large as a diameter of the cord and are joined to each other. For the amount of the unvulcanized rubber in the radial direction of the cord, the reinforcing member element is formed so that the width direction is greater than the thickness direction of the reinforcing member element,
The method of manufacturing a tire reinforcing member according to claim 1, wherein the adjacent reinforcing member elements are joined at a rubber portion at an end portion in the width direction.   The method for manufacturing a tire reinforcing member according to claim 1 or 2, wherein the reinforcing member element is disposed on a rubber sheet.   The tire reinforcement according to any one of claims 1 to 3, wherein the bead core and the carcass are assembled on a cylindrical former to form a green case, and the reinforcing member element is disposed on the green case. Manufacturing method of member.

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