JP2006103458A - Run flat tire and method of manufacturing the run flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a run flat tire with excellent productivity and durability and to provide a method for manufacturing a run flat tire with excellent productivity and uniformity. <P>SOLUTION: The run flat tire is provided with a pair of bead parts 1; side wall parts 2 extending from the bead parts 1 to the outside in a tire radial direction respectively; a carcass layer 4 comprising a carcass ply 14 laid between the bead parts 1 and rolled up by the bead 1a; reinforcement rubber layer 9 arranged on the side wall parts 2; and an annular swelling part 10 swelling from at least one bead part 1 to the outside in a tire width direction and having an annular bead 1b. The run flat tire is provided with an annular rubber body 13 arranged from the bead part 1 to the annular swelling part 10 and integrated with a bead filler 12. An end 15 of the rolled up carcass ply 14 is arranged at a position of 95% or lower of tire radial height h to a tire inner peripheral side end of the bead 1b taking a tire outer peripheral side end of the bead 1a as a reference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a run flat tire and a method for manufacturing the run flat tire.

  A run-flat tire is a tire that can safely travel a certain distance even when the air pressure inside the tire is reduced due to a failure such as puncture. As one of the tire structures for enabling such run-flat running, a run-flat tire having a reinforcing rubber layer on a sidewall portion is known. According to such a run-flat tire, when the air pressure inside the tire decreases, the reinforcing rubber layer supports the tire and prevents it from being completely flattened, and run-flat traveling is possible.

  However, in a state where the air pressure inside the tire is reduced, the pressure on the rim of the bead portion is weakened, so that the fitting force with the rim is reduced and the bead portion is easily detached from the rim. For this reason, a so-called double bead type run-flat tire is proposed in which a bead is arranged in an annular bulging portion bulging outward in the tire width direction of the bead portion separately from the bead arranged on the outer peripheral side of the rim bead seat portion. (See Patent Documents 1 to 3 below). According to such a structure, the annular bulging portion having high elasticity by the bead can hold the rim flange and prevent the rim from coming off during run flat running.

  FIG. 4 is a tire meridian cross-sectional view showing a conventional double bead type run flat tire. The bead portion 1 is provided with a bead 1a and a bead filler 12, and the carcass ply 14 is wound up from the inside to the outside so as to sandwich them. In the sidewall portion 2, a sidewall rubber 11 is disposed on the outer side, and a reinforcing rubber layer 9 having a substantially crescent cross section is disposed on the inner side. The annular bulging portion 10 bulges outward in the tire width direction of the bead portion 1 and has an annular bead 1b. The reinforcing layer 16 is disposed along the inner peripheral surface of the annular bulging portion 10, and the rim strip rubber 17 is disposed in a portion that directly contacts the rim 8.

  In such a run flat tire, since the annular bulging portion 10 is configured by bonding a large number of rubber members, there is a problem that the manufacturing process becomes complicated and the productivity is lowered. Further, during run-flat running, stress from the bead 1b toward the outer side in the tire radial direction is generated along with the stress acting on the annular bulging portion 10 from the rim flange 8a, and the winding end portion 15 of the carcass ply 14 is distorted. There was a problem of concentrating and deteriorating durability. In particular, when the winding end 15 of the carcass ply 14 is disposed in the vicinity of the maximum bending portion B of the reinforcing rubber layer 9, when the reinforcing rubber layer 9 is bent during run-flat running, stress is applied to the winding end 15. There was a tendency for cracks to occur easily.

  On the other hand, the run flat tire as described above has been manufactured through the following manufacturing process. That is, as shown sequentially in FIGS. 5A to 5C, first, the outer peripheral surface of the molding drum is the surface 20 to be formed, and the reinforcing rubber member 18 that becomes the reinforcing rubber layer 9 on the outer peripheral side, the inner liner layer. 5, inner liner rubber 19, rim strip rubber 17 and sidewall rubber 11 are disposed. Further, the carcass ply 14 is disposed on the outer peripheral side, and the bead 1a and the bead filler 12 are extrapolated at predetermined positions. Subsequently, the central portion (left side in FIG. 5) is expanded by a diameter expanding mechanism such as shaping or bladder. And it arrange | positions so that the carcass ply 14 may be rolled up and the bead 1a and the bead filler 12 may be inserted | pinched. The rubber member 22 and the bead 1b constituting the annular bulging portion 10 are disposed outside the wound carcass ply 14, and the rim strip rubber 17 and the sidewall rubber 11 are further wound. Thereafter, the tread portion 3 is formed and the process proceeds to the vulcanization process.

As described above, the method for manufacturing the run flat tire requires a large number of man-hours and the number of parts for forming the bead portion 1 and the annular bulging portion 10 and deteriorates productivity. In addition, since a large number of members are bonded to each other to cause manufacturing variations in the molded product, the tire uniformity tends to decrease.
JP 51-116507 A JP-A-53-138106 JP 2002-178725 A

  Accordingly, an object of the present invention is to provide a run flat tire excellent in productivity and durability and to provide a method of manufacturing a run flat tire excellent in productivity and uniformity.

  The above object can be achieved by the present invention as described below. That is, the run-flat tire of the present invention includes a pair of bead portions each having an annular first bead and a bead filler disposed on the tire outer periphery of the first bead, and sidewalls extending outward from the bead portion in the tire radial direction. A carcass layer formed of a carcass ply spanned between a portion and a bead portion and wound up by the first bead, a reinforcing rubber layer disposed on the sidewall portion, and at least one of the bead portions A run-flat tire having an annular bulging portion that bulges outward in the width direction and has an annular second bead, and is disposed from the bead portion toward the annular bulging portion, and is integrated with the bead filler. And an end portion of the rolled up carcass ply with respect to a tire outer peripheral side end of the first bead. In which it arranged on 95 percent or less of the position in the tire radial direction height to the tire inner peripheral side end of the bead.

  According to the run-flat tire according to the present invention, the formation of the annular bulge portion can be simplified by including the annular rubber body that is disposed from the bead portion toward the annular bulge portion and integrated with the bead filler. As a result, productivity can be improved, and the occurrence of separation can be suppressed and durability can be secured against impacts repeatedly transmitted from the rim flange during traveling. Further, the end of the carcass ply that has been wound up (hereinafter sometimes referred to as the wound-up end) is adjusted to the height of the second bead to the tire inner peripheral end with respect to the tire outer peripheral end of the first bead. By disposing at a position of 95% or less, the winding-up end portion is hardly affected by the stress from the second bead toward the outer side in the tire radial direction or the bending of the reinforcing rubber layer. As a result, it is possible to prevent the concentration of distortion at the winding end and to improve the durability more effectively. Further, by setting the carcass ply winding height lower than the conventional height, the riding comfort performance is improved and the weight of the tire can be reduced.

  In the above, it is preferable that at least one of the first bead and the second bead is integrated with a member in which the bead filler and the annular rubber body are integrated.

  According to the said structure, the man-hour and number of parts which are required for formation of a bead part or a cyclic | annular bulge part can be reduced, work can be simplified and productivity can be improved more.

  In the method for manufacturing a run-flat tire according to the present invention, a predetermined member is disposed on the outer peripheral side of the surface to be formed on the cylindrical shape, and is disposed on the outer periphery of the annular first bead and the tire of the first bead. In the method of manufacturing a run-flat tire, the surface to be formed includes a step of forming a bead portion having a bead filler and an annular bulging portion having an annular second bead bulging outward in the tire width direction of the bead portion. A rim strip rubber is disposed on the outer circumferential side of the rim strip rubber along the tire circumferential direction, and a carcass ply is disposed on the outer circumferential side of the surface to be formed. Disposing the first bead on the outer peripheral side of the portion near the end of the carcass ply, and arranging the bead filler on the outer peripheral side of the surface to be formed through the first bead. And disposing an annular rubber body integrated with the bead filler and the second bead on the outer side in the tire width direction of the bead filler, and an end of the carcass ply at the first bead. And a step of winding up the rim strip rubber.

  The run-flat tire manufacturing method of the present invention is configured to wind up the portion near the end of the carcass ply and the rim strip in a state where the members constituting the bead portion and the annular bulging portion are disposed at predetermined positions. Therefore, the number of steps can be reduced as compared with the conventional case, and the formation of the bead portion and the annular bulge portion can be simplified to improve the productivity. In addition, as compared with a manufacturing method in which a large number of members are bonded, manufacturing variation is reduced and uniformity is improved. Further, since the annular rubber body constituting the annular bulging portion is integrated with the bead filler, the formation of the annular bulging portion can be further simplified, and the number of parts can be reduced.

  In the above, when the portion in the vicinity of the end of the carcass ply is arranged on the outer peripheral side of the rim strip rubber, the end of the rolled up carcass ply is the second on the basis of the tire outer peripheral end of the first bead. What adjusts the position of the edge part so that it may be arranged in the position of 95% or less of the tire radial direction height to the tire inner peripheral side edge of a bead is preferred.

  With the above configuration, the winding end of the carcass ply is not easily affected by the stress from the second bead toward the outer side in the tire radial direction or the bending of the reinforcing rubber layer, and the concentration of strain on the winding end is suppressed, and durability Can be improved.

  In the above, it is preferable that at least one of the first bead and the second bead is integrated with a member in which the bead filler and the annular rubber body are integrated.

  According to the said structure, the man-hour and number of parts which are required for formation of a bead part or an annular bulging part can be reduced effectively, work can be simplified and productivity can be improved more.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of run-flat tires]
FIG. 1 is a tire meridian cross-sectional view showing an example of a run-flat tire according to the present invention. The run flat tire shown in FIG. 1 includes a pair of bead portions 1, a sidewall portion 2 extending from the bead portion 1 outward in the tire radial direction, and a tread portion 3 provided between the sidewall portions 2. The bead portion 1 is provided with a bead 1a (corresponding to the first bead) in which a converging body of bead wires forms an annular shape in the tire circumferential direction. A bead filler 12 having an extending triangular shape is disposed. Further, a rim strip rubber 17 having excellent wear resistance is disposed at a portion that directly contacts the rim 8.

  The carcass layer 4 includes a carcass ply 14 in which cords are arranged in parallel at an angle of approximately 90 ° with respect to the tire equator line C, and is arranged so as to be bridged between the pair of bead portions 1. An inner liner layer 5 for maintaining air pressure is disposed on the inner peripheral side of the carcass layer 4, and a belt layer 6 and a belt reinforcing layer 7 for reinforcing by the effect of the shell are provided on the outer peripheral side of the carcass layer 4. Arranged. The belt layer 6 is composed of a belt ply in which cords are arranged in parallel at a predetermined angle with respect to the tire equator line C.

  A steel wire or the like is used as the bead wire, and steel, organic fibers such as polyester, rayon, nylon, or aramid are used as the cords constituting the carcass layer 4 and the belt layer 6. These cords are usually subjected to surface treatment, adhesion treatment, or the like in order to improve adhesion to rubber.

  In the sidewall portion 2, a sidewall rubber 11 is disposed on the outer side, and a reinforcing rubber layer 9 having a substantially crescent cross section is disposed on the inner side. As a result, when the air pressure inside the tire decreases, the deformation of the tire is suppressed, and run-flat traveling is possible. The reinforced rubber layer 9 is composed of, for example, a rubber layer having a rubber hardness (rubber hardness measured according to JIS K6253 type A durometer hardness test, the same shall apply hereinafter) of 65 to 90 °. The reinforcing rubber layer 9 included in the run-flat tire of the present invention can be applied to any reinforcing rubber layer used in a conventional side-reinforcing type run-flat tire without being particularly limited in terms of hardness and thickness. Can do. The reinforcing rubber layer 9 is not limited to a single rubber layer, and may be composed of a plurality of rubber layers having different physical properties such as hardness.

  The annular bulging portion 10 is formed to bulge outward of the bead portion 1 in the tire width direction. The annular bulging portion 10 of the present embodiment bulges outward in the tire width direction from the rim flange 8a and has an inner circumferential surface along the outer circumferential curved surface of the rim flange 8a. Thereby, the annular bulging portion 10 can effectively hold the rim flange 8a and prevent the rim from coming off. The annular bulging portion 10 is preferably formed on each of the bead portions 1 on both sides. However, the annular bulging portion 10 only needs to be formed on at least one of the bead portions 1, and is formed only on the side that is on the vehicle outer side when mounted, for example. It doesn't matter.

  The run flat tire of the present invention includes an annular rubber body 13 disposed from the bead portion 1 toward the annular bulging portion 10. The annular rubber body 13 preferably has, for example, a rubber hardness of 40 to 75 ° and sufficient rigidity and crack resistance to withstand impacts repeatedly transmitted from the rim 8. The annular rubber body 13 is disposed on the outer side in the tire width direction of the bead filler 12 and is integrated with the bead filler 12. Such an integrated member can be formed, for example, by extruding while joining the rubber materials using a multilayer extruder.

  The annular bulging portion 10 is provided with a bead 1b (corresponding to the second bead) in which a bead wire forms an annular shape in the tire circumferential direction. The bead 1b of the present embodiment is arranged such that the center position of the bead 1b is positioned on the tire outer peripheral side and the tire width direction outer side from the outermost diameter point of the rim flange 8a when the rim is mounted. In the present invention, the position of the bead 1b is not particularly limited. The bead 1b is not limited to the same bead wire converging body as the bead 1a, and may be, for example, an organic fiber converging body or a rubber bead made of fiber reinforced rubber.

  The reinforcing layer 16 is disposed substantially along the inner peripheral surface of the annular bulging portion 10, thereby reinforcing the inner peripheral surface of the annular bulging portion 10 and suppressing wear. Examples of the reinforcing layer 16 include a chafer composed of steel cords and organic fibers such as rayon, nylon, polyester, and aramid. In the present embodiment, an example in which the tire inner peripheral side end of the reinforcing layer 16 is locked on the outer side in the tire width direction of the bead 1a is shown, but the reinforcing layer 16 is wound up from the inner side to the outer side by the bead 1a. It does n’t matter.

  FIG. 2 is a main part sectional view schematically showing an example of a bead part of the run-flat tire of the present invention. The carcass ply 14 is wound up from the inner side to the outer side by a bead 1 a and is disposed along the inner peripheral surface of the annular rubber body 13. The winding end 15 of the carcass ply 14 is disposed at least on the outer side in the tire radial direction from the tire outer peripheral side end of the bead 1a. In the present invention, when the height in the tire radial direction from the bead 1a to the tire inner peripheral end with respect to the tire outer peripheral end of the bead 1a is defined as h, the winding end portion with reference to the tire outer peripheral end of the bead 1a. The tire radial direction height p is set to be 95% or less of the height h. When the height p exceeds 95% of the height h, the winding end portion 15 is easily affected by the stress from the bead 1b toward the outer side in the tire radial direction, and strain is concentrated on the winding end portion 15 to reduce durability. Tend to. In the present invention, the height p is more preferably 85% or less of the height h.

  In the present invention, it is preferable that at least one of the bead 1a and the bead 1b is integrated with a member in which the bead filler 12 and the annular rubber body 13 are integrated. Here, FIG. 2 shows an example in which both the bead 1a and the bead 1b are integrated. Thereby, the man-hour and number of parts required for formation of the bead part 1 and the cyclic | annular bulging part 10 can be reduced significantly, work can be simplified and productivity can be improved. Such an integrated member can be formed, for example, by bonding the bead 1a or the bead 1b to the above-described member in which the bead filler 12 and the annular rubber body 13 are integrated.

  The run flat tire of the present invention has the same structure as a conventional double bead type run flat tire except that the bead portion 1 and the annular bulging portion 10 are configured as described above.

[Production method of run-flat tire]
Hereinafter, the manufacturing method of the run flat tire of this invention is demonstrated. FIG. 3 is a schematic diagram for explaining a method for producing a run-flat tire according to the present invention, in which the arrangement state of each member on the surface to be formed is sequentially shown in (a) to (c). First, a cylindrical forming drum is prepared, and the outer peripheral surface thereof is defined as a forming surface 20. This molding drum is provided with a rubber bag called a bladder at the center (left side in FIG. 3). In addition, a bladder for winding up the carcass ply or the like is provided as necessary. Instead of the bladder, a conventionally known diameter reduction / expansion mechanism having the same function may be adopted.

  Next, the reinforcing rubber member 18 that becomes the reinforcing rubber layer 9 and the inner liner rubber 19 that becomes the inner liner layer 5 are sequentially attached and laminated on the outer peripheral side of the forming surface 20. Subsequently, the rim strip rubber 17 is disposed outside the inner liner rubber 19 in the width direction. The rim strip rubber 17 is disposed so that the end surface of the inner liner rubber 19 abuts or the end portion overlaps.

  The sidewall rubber 11 is preferably disposed outside the rim strip rubber 17 in the width direction. The side wall rubber 11 is arranged so that the end surface of the rim strip rubber 17 is abutted or overlapped. Further, it is preferable that the reinforcing layer 16 is disposed at a predetermined position on the outer peripheral side of the rim strip rubber 17. Examples of the reinforcing layer 16 include those described above.

  Next, the carcass ply 14 is disposed on the outer peripheral side of the surface 20 to be formed. At that time, an end portion vicinity portion 14 a having a predetermined width dimension from the width direction end portion of the carcass ply 14 is disposed on the outer peripheral side of the rim strip rubber 17. Further, in the present invention, when the carcass ply 14 is wound up, the end portion 15 of the carcass ply 14 is the height in the tire radial direction from the tire outer peripheral side end of the bead 1a to the tire inner peripheral end of the bead 1b. It is preferable to adjust the position of the end 15 so that it is disposed at a position of 95% or less of the above.

  Subsequently, an annular bead 1a is extrapolated on the outer peripheral side of the end portion vicinity portion 14a of the carcass ply 14, and the bead filler 12 is disposed on the outer peripheral side of the surface to be formed via the bead 1a. An annular rubber body 13 integrated with the bead filler 12 and a bead 1b are disposed outside the twelve tire width direction. These members are arranged in advance in contact with an annular mold (not shown), and the arrangement work is simplified by extrapolating the annular mold together with the end portion 14a of the carcass ply 14 together with the annular mold. It can be carried out. Such an annular mold is removed before the winding process described later. In the present invention, it is preferable that at least one of the bead 1a and the bead 1b is integrated with a member in which the bead filler 12 and the annular rubber body 13 are integrated. FIG. 3 shows that both the bead 1a and the bead 1b are integrated. An integrated example is shown.

  Then, the bladder provided in the center part of the forming drum is expanded, and the width direction center part (left side in FIG. 3) of the obtained molded product is deformed into a toroid shape. At this time, it is preferable to clamp the bead 1a from the inner peripheral side via the rim strip rubber 17 and the carcass ply 14 by a bead lock mechanism (not shown) embedded in the outer peripheral surface of the molding drum. Thereby, said deformation | transformation can be performed with sufficient precision.

  Further, the bead 1a winds up the vicinity 14a of the end portion of the carcass ply 14 and the rim strip rubber 17, and winds up the reinforcing layer 16 and the side wall rubber 11 together therewith. Such winding operation may be performed manually or collectively, but each member can be easily rolled up by applying internal pressure to the bladder.

  The end portion vicinity portion 14 a of the carcass ply 14, the reinforcing layer 16, and the rim strip rubber 17 are arranged along the inner peripheral surface of the annular rubber body 13 and constitute the inner peripheral surface of the annular bulging portion 10. At this time, the end portion 15 of the carcass ply 14 may be disposed at a position of 95% or less of the height in the tire radial direction to the tire inner peripheral side end of the bead 1b with reference to the tire outer peripheral end of the bead 1a. preferable. Further, the sidewall rubber 11 is arranged along the outer side of the annular rubber body 13 from the annular bulging portion 10 toward the sidewall portion 2.

  Thereafter, the belt layer 6 and the belt reinforcing layer 7 are formed on the tire outer peripheral side of the molded body, and the tread rubber is disposed on the outer peripheral side to form the tread portion 3.

[Another embodiment]
(1) In the above-described embodiment, the example in which the carcass layer 4 is configured by one carcass ply 14 is shown. However, in the present invention, the carcass layer may be configured by a plurality of carcass plies. In such a case, it is preferable that the height p of the winding end portions of all the carcass plies constituting the carcass layer 4 is 95% or less of the height h.

  (2) The run flat tire of the present invention may include a single rubber layer in which the bead filler 12 and the annular rubber body 13 are integrated. The rubber hardness of the single rubber layer is preferably 40 to 75 °. According to the said structure, formation of the annular bulging part 10 is simplified more and productivity can be improved effectively.

  (3) The cross-sectional shapes of the annular bulging portion 10, the annular rubber body 13, and the bead filler 12 are not limited to the shapes shown in the above-described embodiment.

  (4) In the above-mentioned embodiment, although the example which swells the center part of a molding using a bladder was shown, instead of this, bead 1a of both sides is fixed with a bead lock mechanism, for example, and they are made into a center part. You may inflate by shaping by putting air in the center inside.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

(1) Productivity Time required for tire molding was measured to evaluate productivity. The index is evaluated with the conventional example as 100, and the larger the value, the longer the molding time, that is, the higher the productivity.

(2) Uniformity Based on the test method prescribed in JIS D4233, RFV (radial force variation) was measured to evaluate tire uniformity. Specifically, the tire was pressed against the rotating drum so that a predetermined load was applied, and the amount of variation in the reaction force in the radial direction that occurred when the tire was rotated while keeping the distance between both axes constant was measured. The number of samples was 36, and the average value was evaluated. The index is evaluated with the result of the conventional example as 100, and the smaller the index, the smaller the fluctuation amount, that is, the better the uniformity.

(3) Durability test A durability test was performed by the method specified in JIS D4230. In the case where cracks or the like were not confirmed even after completion of the test stage 3, the speed and load were continuously applied to the tire, and the test time until the malfunction was confirmed was measured. In the test, the tire was mounted on a rim having a size of 18 × 8 J, and the tire internal pressure was set to a run flat state of 0 kPa. The index is evaluated with Conventional Example 1 being 100, and the larger the value, the longer the test time, that is, the better the durability.

Conventional Example A run flat tire (size 245 / 40R18) having the structure shown in FIG. 4 was produced by a conventional manufacturing method. That is, as shown in FIG. 5, the carcass ply 14 is wound up so as to sandwich the bead 1a and the bead filler 12, and a large number of members such as the rubber member 22, the reinforcing layer 16, and the bead 1b are attached to the outer peripheral side thereof. A bead portion 1 and an annular bulge portion 10 were formed.

Example A run flat tire (size size 245 / 40R18) having the structure shown in FIGS. 1 and 2 was produced by the production method of the present invention. That is, as shown in FIG. 3, a member in which the bead 1a, the bead filler 12, the annular rubber body 13, and the bead 1b are integrated is disposed on the outer peripheral side of the end portion vicinity 14a of the carcass ply 14, and the bead 1a Then, the bead portion 1 and the annular bulging portion 10 were formed by collectively winding up the vicinity 14a of the end portion of the carcass ply 14 and the rim strip rubber 17 and the like. The results are shown in Table 1.

表１の結果が示すように、実施例は、部品点数および工数が比較的少なく、ビード部および環状膨出部の形成が容易であることにより、従来例よりも生産性に優れていることがわかる。また、多数の部材を貼り付けて作製した従来例と比べて、ユニフォミティに優れていることがわかる。更に、ビードフィラーと環状ゴム体とを一体化しつつ、巻き上げ端部を所定の高さとすることにより、従来例よりも耐久性に優れていることが分かる。

As shown in the results of Table 1, the example has a relatively low number of parts and man-hours, and it is easier to form the bead part and the annular bulge part. Recognize. Moreover, it turns out that it is excellent in uniformity compared with the prior art example which affixed many members and produced. Furthermore, it turns out that it is excellent in durability rather than a prior art example by making a winding end part into predetermined height, integrating a bead filler and a cyclic | annular rubber body.

Tire meridian cross-sectional view showing an example of a run-flat tire according to the present invention Sectional drawing of the principal part which showed typically an example of the bead part of the run flat tire which concerns on this invention Schematic cross-sectional view illustrating a method for producing a run-flat tire of the present invention Tire meridian cross-sectional view showing an example of a conventional run-flat tire Cross-sectional schematic diagram for explaining a conventional method for producing a run-flat tire

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead part 1a Bead 1b Bead 2 Side wall part 4 Carcass layer 8 Rim 8a Rim flange 9 Reinforcement rubber layer 10 Annular bulging part 11 Side wall rubber 12 Bead filler 13 Annular rubber body 14 Carcass ply 14a End vicinity 15 Carcass ply End portion 16 Reinforcement layer 17 Rim strip rubber C Tire equator line h Tire radial direction height p of bead 1a from tire outer peripheral end of bead 1a to tire inner peripheral end Tire radial height at the end of the carcass ply as a reference

Claims (5)

A pair of bead portions having an annular first bead and a bead filler disposed on the outer periphery of the tire of the first bead, a sidewall portion extending outward in the tire radial direction from the bead portion, and a bridge between the bead portions A carcass layer made of a carcass ply wound up by the first bead, a reinforcing rubber layer disposed on the sidewall portion, and bulges outward in the tire width direction from at least one of the bead portions. In a run flat tire provided with the annular bulging part which has the 2nd bead,
An annular rubber body that is disposed from the bead portion toward the annular bulging portion and integrated with the bead filler is provided, and an end portion of the rolled-up carcass ply is used as a tire outer peripheral side end of the first bead. A run-flat tire characterized by being arranged at a position that is 95% or less of the height in the tire radial direction to the tire inner peripheral side end of the second bead with reference to.   The run flat tire according to claim 1, wherein at least one of the first bead and the second bead is integrated with a member in which the bead filler and the annular rubber body are integrated. A bead portion having a predetermined member disposed on an outer peripheral side of a surface to be formed on a cylindrical shape and having an annular first bead and a bead filler disposed on an outer periphery of the tire of the first bead, and a tire of the bead portion In a method for producing a run-flat tire comprising a step of forming an annular bulging portion having an annular second bead bulging outward in the width direction,
Disposing rim strip rubber along the tire circumferential direction on the outer peripheral side of the surface to be formed;
Disposing a carcass ply on the outer peripheral side of the surface to be formed and disposing a portion near the end of the carcass ply on the outer peripheral side of the rim strip rubber; and
The first bead is disposed on the outer peripheral side in the vicinity of the end portion of the carcass ply, the bead filler is disposed on the outer peripheral side of the formation surface via the first bead, and the bead filler tire is provided. A step of disposing an annular rubber body integrated with the bead filler on the outer side in the width direction and the second bead;
And a step of winding up the rim strip rubber and the vicinity of the end portion of the carcass ply with the first bead.   When the portion near the end of the carcass ply is disposed on the outer peripheral side of the rim strip rubber, the end of the carcass ply that has been rolled up is the tire of the second bead based on the tire outer peripheral side end of the first bead. The method of manufacturing a run-flat tire according to claim 3, wherein the position of the end portion is adjusted so as to be disposed at a position of 95% or less of the height in the tire radial direction to the inner peripheral side end.   The method of manufacturing a run flat tire according to claim 3 or 4, wherein at least one of the first bead and the second bead is integrated with a member in which the bead filler and the annular rubber body are integrated.

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