JP4507920B2 - Method for manufacturing run-flat tires - Google Patents

Description

  The present invention relates to a method for manufacturing a side-reinforced run-flat tire in which a second bead is disposed on an annular bulging portion that bulges outward in the tire width direction of a bead portion.

  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. 9 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, there is a problem that when the side reinforcing portion is bent and tension is generated in the carcass during the run-flat running, the bead toe is easily lifted, and therefore the bead is easily detached. In order to avoid this, if the tightening force of the bead is increased or the amount of deflection of the tire is decreased, excessive reinforcement is required, which causes a problem of difficulty in assembling the rim and an increase in weight.

  On the other hand, the run flat tire as described above has been manufactured through the following manufacturing process. That is, as sequentially shown in FIGS. 10A to 10C, first, the outer peripheral surface of the molding drum is the surface 20 to be formed, and the inner liner rubber 19 that becomes the inner liner layer 5 on the outer peripheral side, and the reinforcing rubber. Reinforcing rubber members 18 to be the layers 9 are respectively disposed. And the carcass ply 14 is arrange | positioned in the outer peripheral side, and the bead 1a and the bead filler 12 are extrapolated to a predetermined position. Subsequently, the carcass ply 14 is wound up and disposed so as to sandwich the bead 1a and the bead filler 12. Next, the bead 1a, the bead filler 12 and the carcass ply 14 are brought close to each other by means such as slightly expanding the forming surface 20 of the molding drum. On the outer peripheral side of the carcass ply 14, a reinforcing layer, rim strip rubber, sidewall rubber, and the like are disposed in addition to the rubber member 22 and the second bead 1 b that constitute the annular bulging portion 10. As the second bead 1b, a bead wire spirally wound and separately produced as an assembly of bead wires is used. Thereafter, the molded product is deformed along the tire shape, the tread portion 3 is formed, and the process proceeds to the vulcanization process.

  However, the manufacturing method described above requires a mechanism for attaching the annular second bead 1b so as not to be eccentric with respect to the tire shaft. In addition, when producing an assembly of bead wires in advance, there is a problem that a winding support mechanism and a device for converging the assembly become large. Furthermore, since the second bead 1b is disposed before the molded product is expanded / deformed into a tire shape, the second bead 1b is likely to be eccentric or deformed in cross-section when the molded product is expanded / deformed. There is a problem of becoming.

On the other hand, in a normal pneumatic tire that is not a run-flat tire, a tire manufacturing method is known in which a bead wire is spirally wound on a molded product to form a bead (corresponding to a first bead) (for example, Patent Documents). 4-5). However, these manufacturing methods employ a construction method in which an annular core having the same outer shape as the inner surface shape of the tire is used, and components are sequentially disposed (pasted) on the tire. Such a construction method is not adopted. Therefore, in the method of manufacturing a run flat tire, a method for forming a bead by spirally winding a bead wire on a molded product has not been known so far.
JP 51-116507 A JP-A-53-138106 JP 2002-178725 A JP-T-2004-501815 Special table 2003-514706 gazette

  Accordingly, an object of the present invention is to provide a method for producing a run flat tire that can produce a run flat tire having good uniformity with simple equipment and processes because eccentricity is less likely to occur than in the conventional method. It is in.

  The above object can be achieved by the present invention as described below.

  That is, the method for producing a run-flat tire according to the present invention includes a step of disposing an inner liner rubber, a reinforcing rubber member that reinforces both side wall portions, and a carcass ply at predetermined positions on the outer periphery of the molding drum, and a pair of first tires. A step of disposing one bead and a bead filler and deforming the inside of the first bead into a toroidal shape, a step of winding and attaching the end of the carcass ply before or after the deformation, and a toroidal molding A step of affixing a rubber member constituting an annular bulge to the side of the bead filler of the object, and a cord is helically affixed to the rubber member while rotating the formed product around the axis And forming a second bead.

  According to the run-flat tire manufacturing method of the present invention, an annular second bead is disposed to spirally attach the cord to the rubber member while rotating the toroidal molded product around the axis. Eccentricity prevention mechanism like the conventional apparatus becomes unnecessary. In addition, as compared with the conventional method, eccentricity is less likely to occur at the time of pasting, and eccentricity at the time of expansion / deformation of the molded product, deformation of the cross-sectional shape, and the like are less likely to occur, and the uniformity is improved. In addition, since it is not necessary to prepare an assembly of bead wires in advance and it can be manufactured by adding only a cord attaching device, a tire can be manufactured with simple equipment and processes.

  In the above, the inner liner rubber and the reinforcing rubber member that reinforces the side wall portions are disposed at predetermined positions on the outer periphery of the molding drum, and the cords are further extended outward from the vicinity of the outer end of each reinforcing rubber member in the drum width direction. Each of which arranges carcass plies arranged in the width direction, a step of arranging a pair of first beads and bead filler slightly outside the inner end in the drum width direction of the carcass ply, and Forming the toroid-shaped molded product by a step of deforming the inner side of the first bead into a toroidal shape and a step of winding and sticking the outer end of each carcass ply on the outer peripheral side of the deformed molded product. It is preferable to do.

  According to this manufacturing method, after the carcass ply is disposed outside the reinforcing rubber member, the pair of first beads and the bead filler are disposed slightly outside the inner end, and then the inner side from the first bead is formed in a toroidal shape. Therefore, the inner winding portion of the carcass ply can be easily disposed inside the bead. Further, since the outer end of the carcass ply is wound up and attached to the outer peripheral side of the molded product thus obtained, the carcass ply can be easily crimped to the reinforcing rubber member after shaping. As a result, it is possible to manufacture a run-flat tire with excellent bead removal durability without increasing the weight with good productivity. In addition, since one end of the carcass ply is a tire wound from the outside of the first bead to the inside, when the side reinforcing portion is bent and a tension is applied to the carcass during run flat running, a moment is generated around the bead and a bead toe is generated. Is pressed against the bead sheet of the rim, so that the bead is less likely to come off.

Further, the cord is a cord coated with unvulcanized rubber, and the cord is spirally attached to the same surface, and then the cord is spirally formed on the upper surface of the surface formed by the attached cord. It is preferable to repeat the process of attaching to the substrate. When a cord coated with unvulcanized rubber is used, adhesion between the cords is facilitated, and a second bead composed of a plurality of layers can be formed by repeating the above steps.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a tire meridian cross-sectional view showing an example of a run-flat tire obtained by the manufacturing method of the present invention, and FIG. 2 is a main part cross-sectional view schematically showing the bead portion. Moreover, FIGS. 3-5 is process drawing which shows an example of the manufacturing method of this invention.

  The method for producing a run-flat tire according to the present invention includes a step of disposing an inner liner rubber, a reinforcing rubber member that reinforces both sidewall portions, and a carcass ply at predetermined positions on the outer periphery of the molding drum, and a pair of first beads. And a step of disposing the bead filler to deform the inside of the first bead into a toroid shape, and a step of winding and attaching the end portion of the carcass ply before or after the deformation, thereby forming a toroid shape. To obtain a molded product. Further, the present invention provides a step of attaching a rubber member constituting an annular bulging portion to the side of the bead filler of the toroid-like molded product, and while rotating the molded product after the attachment around the axis, Forming a second bead by affixing a cord to the rubber member in a spiral shape.

  In the present embodiment, as shown in FIGS. 3 to 5, an inner liner rubber 19 and a reinforcing rubber member 18 that reinforces both side wall portions are disposed at predetermined positions on the outer periphery of the molding drum 20, and the respective reinforcements are provided. A step of disposing a carcass ply 14 in which cords are arranged in the width direction on the outer side from the vicinity of the outer end of the rubber member 18 in the drum width direction, and a pair of first steps slightly outside the inner end of the carcass ply 14 in the drum width direction A step of disposing one bead 1a and a bead filler 12, a step of deforming the inner side of the obtained molded product from the first bead 1a into a toroid, and the respective carcass on the outer peripheral side of the molded product after the deformation. An example in which the toroid-shaped molded product is formed by the step of winding and attaching the outer end 14b of the ply 14 will be described.

  First, the run flat tire obtained by this embodiment will be described.

[Run-flat tire of this embodiment]
As shown in FIGS. 1 to 2, the run-flat tire of the present embodiment is provided between a pair of bead parts 1, a sidewall part 2 that extends outward from the bead part 1 in the tire radial direction, and the sidewall part 2. Provided tread portion 3. 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, and a cross-section is formed in the tire radial direction on the tire outer periphery of the bead 1a. 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 carcass plies 14 in which cords are arranged at an angle of about 90 ° with respect to the tire equator line C, and is provided for each of the pair of bead portions 1. The carcass ply 14 has one end 14 a wound up from the outside of the first bead 1 a and the other end 14 b arranged inside the belt layer 6.

  In the present invention, the other end 14 b of the carcass ply 14 is preferably disposed in a range of 60 to 90% of the width on both outer sides of the widest layer (usually the innermost layer) of the belt layer 6. As a result, the tire reinforcement effect in cooperation with the belt layer 6 can be maintained, the weight of the tire can be reduced, and the rolling resistance and riding comfort can be improved.

  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 for reinforcing by the effect of the hoop on the inner peripheral side of the tire of the tread portion 3 and if necessary The belt reinforcing layer 7 is disposed. 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.

  In the present embodiment, as shown in FIG. 2, an annular bulging portion 10 that bulges outward from at least one bead portion 1 in the tire width direction and has a second bead 1b is further provided. The annular bulging portion 10 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. It is preferable that the annular bulging portions 10 are respectively formed on the bead portions 1 on both sides.

  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 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.

  As shown in FIG. 2, the carcass ply 14 is wound up from the outside to the inside by a bead 1 a, and one end 14 a thereof is disposed in the vicinity of the bottom side of the bead filler 12. The height H of the bead filler 12 can vary, for example, in the range of 15 to 65 mm, but the height P of the one end 14a of the carcass ply 14 with respect to the tire outer peripheral side end of the bead 1a is in the range of 10 to 20 mm. From the viewpoint of bead durability and weight reduction, it is preferable.

  In addition, the cross-sectional shapes of the annular bulging portion 10, the annular rubber body 13, and the bead filler 12 of the run flat tire obtained by the present invention are not limited to the shapes shown in the present embodiment.

[Production method of run-flat tire]
Next, a method for manufacturing the run flat tire of this embodiment will be described with reference to FIGS.

  First, a cylindrical forming drum 20 is prepared. The forming drum 20 has a conventionally known diameter-reducing / expanding mechanism, and includes a bladder for shaping or a diameter-enlarging mechanism having a similar function at the center. In addition, a bladder mechanism for winding up the outer end of the carcass is provided as necessary.

  Next, as shown in FIG. 3A, an inner liner rubber 19, a reinforcing rubber member 18 that reinforces both side wall portions, and a carcass ply 14 are disposed at predetermined positions on the outer periphery of the molding drum 20, respectively. The process to perform is implemented. Specifically, the center of the inner liner rubber 19 is disposed at the center of the outer periphery of the molding drum 20, and the reinforcing rubber members 18 are disposed on both sides at an interval of the tread width from the center. In addition, the carcass ply 14 is arranged on the outer side from the vicinity of the outer end of each reinforcing rubber member 18 in the drum width direction. At this time, the cords constituting the carcass ply 14 are arranged in the drum width direction.

  In the present embodiment, an example in which the rim strip rubber 17 and the reinforcing layer 16 are disposed on the outer side in the width direction of the inner liner rubber 19 is shown. The rim strip rubber 17 is preferably disposed so that the end surface of the inner liner rubber 19 abuts or the end portion overlaps.

  Next, as shown in FIG. 3B, a step of arranging a pair of first beads 1a and bead fillers 12 slightly outside the inner end in the drum width direction of the carcass ply 14 is performed. The first bead 1a and the bead filler 12 may be sequentially extrapolated, but it is preferable to dispose the first bead 1a and the bead filler 12 integrally.

  Next, as shown in FIG. 3C, a step of deforming the inner side of the obtained molded product from the first bead 1a into a toroid shape is performed. This deformation can be performed by the forming drum 20. At this time, a bead lock mechanism may be provided in the molding drum 20 and the bead 1a may be clamped from the tire inner peripheral side via the rim strip rubber 17 and the carcass ply 14 and the like. Thereby, deformation can be performed with high accuracy. Due to this deformation, one end 14a of the carcass ply 14 is sandwiched between the inner liner rubber 19 and the first bead 1a. FIG. 3C shows an example in which both side surfaces of the enlarged diameter portion of the forming drum 20 are substantially flat. Both side surfaces of the enlarged diameter portion are curved surfaces that are convex outward as in the shape of the tire inner surface. It is preferable to form it.

  Next, as shown in FIG. 4A, a step of winding and sticking the outer end (other end 14b) of each carcass ply 14 around the outer peripheral side of the deformed molded product is performed. By this step, a toroid-shaped molded product is formed.

  At that time, the carcass ply 14 can be wound up manually or collectively in a state where the bead 1a is fixed using a bead lock mechanism if necessary. Moreover, the carcass ply 14 can be easily wound up by setting a rubber bag called a bladder and applying an internal pressure. At this time, since the reinforcing layer 16 and the rim strip rubber 17 are wound up at the same time, a separator is interposed between them and the carcass ply 14, and the reinforcing layer 16 and the like are peeled off and then the next step is performed. Good.

  As shown in FIG. 4B, the present invention includes a step of attaching a rubber member 13 constituting an annular bulging portion to the side of a bead filler 12 of a toroid-shaped molded product. The annular rubber body 13 is composed of the same or two or more types of rubber members 13a and 13b. 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 attached to the outside of the bead filler 12 in the tire width direction with the carcass ply 14 interposed.

  In the present invention, as shown in FIG. 4 (c), the second bead 1b is formed by affixing the cord BW to the rubber member 13 in a spiral shape while rotating the formed product around the axis. Process. FIGS. 5A to 5B show this process in more detail. In the illustrated example, as shown by the arrow, the cord BW is first attached spirally from the inner periphery side to the outer periphery side, but may be applied in the opposite direction.

  One or a plurality of cords BW can be attached at the same time, but it is preferable to attach them one by one from the viewpoint of uniformity, strength, productivity, and the like. As a material of the cord BW, steel wires, steel cords, organic fibers such as polyester, rayon, nylon, and aramid can be used. In other words, in the conventional method, since an annular bead is prepared in advance, it was difficult to maintain an annular shape with organic fibers. become.

  Further, from the viewpoint of facilitating adhesion between the cords, it is preferable to use a cord coated with unvulcanized rubber. Examples of the unvulcanized rubber include those used when the first bead is manufactured. For example, rubber having a rubber viscosity of 50 to 80 is used. Here, the rubber viscosity is a value measured according to the “Mooney Viscosity Test” in the “Unvulcanized Rubber Physical Test Method” of JIS K6300.

  In the present invention, it is sufficient that the code BW is affixed in a spiral shape, and the code BW may circulate at random (this is also included in a spiral shape). As shown in FIG. The cord BW is preferably affixed spirally on the same surface. Further, it is preferable to subsequently repeat the process of attaching the cord BW to the upper surface in a spiral shape.

  In the present embodiment, an example is shown in which the cord BW is affixed in a spiral shape with 5 turns on the first face, 4 turns on the next face, 3 turns, and 2 turns. By gradually reducing the number of turns in this way, the shape of the second bead 1b can be easily maintained after the vulcanization step. Moreover, it becomes easy to maintain the shape of the 2nd bead 1b similarly after a vulcanization | cure process by sticking the uppermost layer to 2 rounds or more. After the cord BW is affixed spirally on the same surface, the cord BW is affixed spirally along the recess formed by the two cords by turning it and then affixing it spirally on the top surface. Can be attached.

  Next, as shown in FIG. 4C, the reinforcing layer 16 and the rim strip rubber 17 are rolled up and pasted at predetermined positions. Further, the sidewall rubber 11 is disposed from the annular bulging portion 10 toward the sidewall portion 2 along the outer peripheral surface of the annular rubber body 13. 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, a toroidal shape in which the other end of each carcass ply is wound up from the outside to the inside by using two carcass plies and winding up and sticking the outer ends of the respective carcass plies. Although the example which forms a molding was shown, the run flat tire which has the same carcass structure as the conventional one as shown in FIG. 6 can be manufactured using one carcass ply. Even in this case, the step of forming the second bead 1b by affixing the cord BW to the rubber member 13 in a spiral shape while rotating the molded product around the axis center in the same manner as in the above-described embodiment. it can.

  That is, according to the present invention, as shown in FIGS. 7A to 7C, the inner liner rubber 19, the reinforcing rubber member 18 that reinforces both side wall portions, and the carcass ply 14 at a predetermined position on the outer periphery of the molding drum 20. , A step of disposing a pair of first beads 1a and bead fillers 12 to deform the inside of the first beads 1a in a toroid shape, and the carcass ply 14 before or after the deformation. What is necessary is just to include the process of winding up and sticking the edge part of.

  Specifically, the cylindrical forming drum 20 as described above is prepared, and as shown in FIG. 7A, the inner liner rubber 19 and both side wall portions are provided at predetermined positions on the outer periphery of the forming drum 20. A reinforcing rubber member 18 to be reinforced and a carcass ply 14 are disposed. At this time, the center of the inner liner rubber 19 is disposed at the center of the outer periphery of the molding drum 20, the reinforcing rubber members 18 are disposed on both sides at an interval of the tread width from the center, and further at the center. The carcass ply 14 is disposed so that the center of the carcass ply 14 is located. At this time, the cords constituting the carcass ply 14 are arranged in the drum width direction.

  Although not shown, the rim strip rubber 17 and the reinforcing layer 16 may be disposed outside the inner liner rubber 19 in the width direction. The rim strip rubber 17 is preferably disposed so that the end surface of the inner liner rubber 19 abuts or the end portion overlaps.

  Next, a step of arranging a pair of first beads 1 a and bead fillers 12 at the position of the first beads 1 a in the carcass ply 14 is performed. The first bead 1a and the bead filler 12 may be sequentially extrapolated, but it is preferable to dispose the first bead 1a and the bead filler 12 integrally.

  Next, as shown in FIG. 7B, a step of winding and attaching the end portion of the carcass ply 14 is performed, but this step may be performed after the step of deforming the molded product into a toroid shape. By this affixing step, the first bead 1a and the bead filler 12 are sandwiched by the carcass ply 14 that has been wound up.

  Subsequently, as shown in FIG.7 (c), the process of transforming the inner side from the 1st bead 1a of the obtained molded object to a toroid form is implemented. By this step, a toroid-shaped molded product is formed. This deformation can be performed by the forming drum 20. At this time, a bead lock mechanism may be provided in the molding drum 20 and the bead 1a may be clamped from the tire inner peripheral side via the rim strip rubber 17 and the carcass ply 14 and the like. Thereby, deformation can be performed with high accuracy.

  Next, as shown in FIG. 7C, the rubber member 13 constituting the annular bulging portion is attached to the side of the bead filler 12 of the toroid-shaped molded product. This process is the same as in the above-described embodiment. Can be done.

  Further, as shown in FIG. 7 (d), the second bead 1b is formed by affixing the cord BW to the rubber member 13 in a spiral shape while rotating the molded product after pasting around the axis. This step can also be performed in the same manner as in the previous embodiment.

  (2) In the above-described embodiment, when the cord is affixed in a spiral shape, an example is shown in which the first surface is affixed 5 times, the next surface is affixed 4 times, a further 3 laps, and a second affix. When forming the second bead 1b by sticking the cord BW in a spiral shape, various forms can be taken as shown in FIG.

  The shapes shown in the figure are shapes (trapezoids or triangles) in which the number of turns decreases as the upper layer, but shapes such as a quadrangle where the number of turns of each layer is equal, or a shape that decreases after increasing the number of turns (one end) ( It may be a hexagon or octagon).

  Among the above, the trapezoid is most preferable as the shape of the second bead from the viewpoints of preventing bead disengagement, rim assembly, workability, and weight reduction.

  (3) In the above-described embodiment, an example in which molding is performed using a single sheet or plate-like material as an inner liner rubber, a reinforcing rubber member, a rim strip rubber, a sidewall rubber, a tread rubber, etc. has been shown. Any of these members can be disposed by winding a continuous rubber strip in a spiral shape to obtain a predetermined shape (so-called strip method).

  Specifically, by rotating the molding drum or molding around the axis, discharging the rubber band from the rubber extrusion device and moving the pasting position while pasting, the arrangement of the members by the strip method Is possible. As this strip method, various methods are known and any of them can be adopted.

  (4) In the above-described embodiment, the example in which the rim strip rubber and the reinforcing layer are disposed in advance on the outer side in the width direction of the inner liner rubber of the molding drum has been shown. After the rubber member constituting the bulging portion is attached, the rim strip rubber and the reinforcing layer may be disposed and then rolled up.

  According to this manufacturing method, the winding process of the carcass ply and the winding process of the rim strip rubber and the reinforcing layer can be sequentially performed using a rubber bag called a bladder.

Tire meridian cross-sectional view showing an example of a run-flat tire obtained in the present invention Sectional drawing of the principal part which showed typically an example of the bead part of the run flat tire obtained by this invention Process drawing which shows an example of the manufacturing method of the run flat tire of this invention Process drawing which shows an example of the manufacturing method of the run flat tire which concerns on this invention Process drawing which shows an example of the manufacturing method of the run flat tire which concerns on this invention Tire meridian cross-sectional view showing another example of a run-flat tire obtained in the present invention Process drawing which shows the other example of the manufacturing method of this invention The principal part figure which shows the other example of the run flat tire obtained by this invention Tire meridian cross-sectional view showing an example of a conventional run-flat tire Process drawing explaining the manufacturing method of the conventional run flat tire

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead part 1a 1st bead 1b 2nd bead 9 Reinforcement rubber layer 10 Annular bulging part 11 Side wall rubber 12 Bead filler 13 Annular rubber body 14 Carcass ply 14a One end (inner side)
14b The other end (outside)
18 Reinforcing rubber member that reinforces the sidewall portion 19 Inner liner rubber 20 Molding drum C Tire equator line BW cord

Claims (3)

  A step of disposing an inner liner rubber, a reinforcing rubber member that reinforces both side wall portions, and a carcass ply at a predetermined position on the outer periphery of the molding drum; a pair of first beads and a bead filler; A step of deforming the inner side of one bead into a toroidal shape, a step of winding and attaching the end of the carcass ply before or after the deformation, and an annular bulging portion on the side of the bead filler of the toroidal shaped product And a step of forming a second bead by spirally attaching a cord to the rubber member while rotating the attached molded product around an axis. A method for manufacturing a flat tire.   An inner liner rubber and a reinforcing rubber member that reinforces both side wall portions are arranged at predetermined positions on the outer periphery of the molding drum, and the cord extends in the width direction further from the outer end in the drum width direction of each reinforcing rubber member. Each of the carcass plies arranged on the inner side, a step of disposing a pair of first beads and bead filler slightly outside the inner end of the carcass ply in the drum width direction, and the first of the obtained molded product. The step of deforming the inner side of the bead into a toroidal shape, and the step of winding and attaching the outer end of each carcass ply to the outer peripheral side of the deformed molded product, forming the toroidal molded product. A method for producing a run-flat tire according to claim 1. The cord is a cord coated with unvulcanized rubber, and the cord is spirally attached to the same surface, and then the cord is spirally attached to the upper surface of the surface formed by the pasted cord. The method for producing a run-flat tire according to claim 1 or 2, wherein the attaching step is repeated.

Images