JP4411928B2 - Tire molding method - Google Patents

Description

  The present invention relates to a tire molding method for molding a portion arranged on the inner peripheral side of a green tire in the manufacture of a radial tire capable of so-called run-flat running.

Conventionally, when manufacturing this type of tire, an inner liner is wound around the outer peripheral surface of the forming drum, and a reinforcing layer is formed by winding a belt-shaped reinforcing material around both ends of the inner liner in the width direction. A carcass material is wound around the layer, a bead is assembled to this layer, transferred to another forming drum, and then bulged in a toroidal shape in the radial direction to form an inner peripheral side green tire, which is then belt material, tread material, etc. (See, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-309789

  By the way, in the conventional example, when the reinforcing material is wound on the inner liner, the reinforcing drum and the inner liner in the width direction central portion are enlarged by expanding the diameter of the central portion in the width direction of the forming drum by the thickness of the reinforcing material. However, in this case, since the carcass material and the inner liner wound on the inner liner are in close contact with each other without any gap, the air between the reinforcing layer and the carcass material, or the reinforcing layer The air between the inner liner and the inner liner cannot be discharged to the center side in the width direction of the inner liner. For this reason, there is a problem in that air accumulation occurs between the reinforcing layer and the carcass material, or between the reinforcing layer and the inner liner, causing separation between the reinforcing layer and the carcass material or the inner liner and a decrease in uniformity. there were.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a tire that does not cause air accumulation between the reinforcing layer and the carcass material or between the reinforcing layer and the inner liner. It is to provide a molding method.

In order to achieve the above object, according to the present invention, an inner liner is wound around the outer peripheral surface of a molding drum, and a reinforcing layer is formed by winding a belt-shaped reinforcing material around both ends of the inner liner in the width direction. In the tire molding method of molding the inner peripheral side green tire before bulging in the radial direction by winding the carcass material around the liner and the reinforcing layer, the both ends in the width direction corresponding to the reinforcing layer are outer diameters than the center side in the width direction. A small-diameter forming drum is used, an air vent hole is formed at least in the width direction center side of the carcass material, and the carcass material and the reinforcing layer are sequentially formed from the both ends in the width direction toward the width direction center side. is crimped to the side, as the difference of the radius of the widthwise center side and the small diameter portion of the forming drum is molded into a 90% to 70% of the thickness of the reinforcing layer That.

As a result, a gap is formed between the center side in the width direction of the carcass material and the inner liner, so the air between the reinforcing layer and the carcass material or the air between the reinforcing layer and the inner liner is the carcass material. Is discharged to the outside through the air vent hole from between the center side in the width direction and the inner liner .

According to the tire molding method of the present invention , the air between the reinforcing layer and the carcass material or the air between the reinforcing layer and the inner liner is discharged to the outside through the air vent hole between the carcass material and the inner liner. Therefore, there is no air accumulation between the reinforcing layer and the carcass material, or between the reinforcing layer and the inner liner, and the peeling between the reinforcing layer and the carcass material or the inner liner is surely prevented. It is possible to improve the uniformity.

  1 to 4 show an embodiment of the present invention, FIG. 1 is a front view of a forming drum, FIG. 2 is a partially sectional front view showing an inner peripheral side green tire formed by the forming drum, and FIG. 4 is a front cross-sectional view of the main part showing the molding process.

  In the tire molding method shown in the present embodiment, in manufacturing a radial tire capable of so-called run-flat running, an inner peripheral side green tire 5 including an inner liner 1, a reinforcing material 2, a carcass material 3 and a bead 4 is formed with a molding drum 10. It is used to mold.

  That is, the inner liner 1 is wound around the outer peripheral surface of the forming drum 10, and the reinforcing layer 2a is formed by winding the belt-shaped reinforcing material 2 on both ends of the inner liner 1 in the width direction, so that the inner liner 1 and the reinforcing layer 2a are formed. A carcass material 3 is wound on the bead 4 and a bead 4 is assembled thereto to form an inner peripheral side green tire 5.

  The forming drum 10 used in the present embodiment is formed in a cylindrical shape so that each member can be wound around the surface, and portions other than the shapes described in detail below have a known configuration.

  That is, the molding drum 10 includes a large diameter portion 11 formed on the center side in the width direction of the outer peripheral surface, a small diameter portion 12 formed on each side in the width direction, and the large diameter portion 11 and the small diameter portion 12. The taper portion 13 is formed, and is rotatably supported by a molding apparatus main body (not shown) via a rotation shaft 14. Although not shown, the outer peripheral surface of the forming drum 10 is composed of a plurality of segments divided in the circumferential direction, and by moving each segment in the radial direction of the forming drum 10, the outer diameter of the outer peripheral surface is enlarged or It is configured so that it can be reduced.

  The large diameter portion 11 has an outer diameter that is uniformly formed in the width direction, and its width A1 is 40% to 60% of the total width A2 of the forming drum 10.

  The outer diameter of the small diameter portion 12 is uniformly formed in the width direction, and the radius R1 of the small diameter portion 12 is such that the difference R3 with the radius R2 of the large diameter portion 11 is 70% to 90% of the thickness B of the reinforcing layer 2a. Is formed. In this case, it is preferable that the outer diameter of the large diameter portion 11 is formed to be larger by 3% to 4% than the outer diameter of the small diameter portion 12.

  The taper portion 13 is formed so that the outer diameter gradually decreases from the large diameter portion 11 toward the small diameter portion 12, and is formed to have a width substantially equal to the width of the small diameter portion 12 in the figure. The width is preferably 1 to 1.5 times the width of the tapered portion 13.

  Next, with reference to FIGS. 3 and 4, a method of forming the inner peripheral side green tire 5 using the forming drum 10 will be described.

  First, as shown in FIG. 3A, the inner liner 1 having a width wider than that of the molding drum 10 is wound around the surface of the molding drum 10. In this case, a slight tension is applied to the inner liner 1 in the circumferential direction of the forming drum 10 or the winding is performed without applying a tension.

  Next, as shown in FIG. 3 (b), the diameter of the forming drum 10 is expanded to extend the peripheral length of the inner liner 1 by approximately 4%, and then the reinforcing member 2 is attached to the small diameter portion 12 and the taper of the forming drum 10. The reinforcing layer 2 a is formed by winding the inner liner 1 so as to correspond to the portion 13. In this case, the reinforcing material 2 is wound around the inner liner 1 so that the circumferential tension is increased by 0.5% to 1%.

  Subsequently, a carcass material 3 wider than the inner liner 1 is wound around the inner liner 1 and the reinforcing material 2 as shown in FIG. At this time, the step R3 with respect to the large diameter portion 11 of the forming drum 10 is formed to be 70% to 90% of the thickness B of the reinforcing layer 2a. A gap R4 of 30% to 10% of the thickness B of the reinforcing layer 2a is formed in between. A large number of air vent holes (not shown) are formed in advance at least in the center in the width direction of the carcass material 3, for example, by cutting the carcass material 3 with a sharp tool or the like. In this case, if the air vent hole is provided at the position 3a corresponding to the inner end of the reinforcing layer 2a in the carcass material 3, the air can be easily discharged to the outside.

  Thereafter, as shown in FIG. 4 (b), both ends of the inner liner 1 and the carcass material 3 in the width direction are folded back to the center in the width direction so as to wrap the beads 4, and the folded portion of the carcass material 3 is reinforced by the stitcher 20 The inner periphery side green tire 5 before bulging in the radial direction is formed by pressure bonding to the 2a side. At that time, the carcass material 3 is sequentially crimped to the reinforcing layer 2a side while the stitcher 20 is moved from both ends in the width direction of the carcass material 3 toward the center in the width direction, and at the same time, the reinforcing layer 2a and the inner liner 1 are also crimped. As a result, the air between the reinforcing layer 2a and the carcass material 3 and the air between the reinforcing layer 2a and the inner liner 1 are discharged into the gap R4 between the center side in the width direction of the carcass material 3 and the inner liner 1. . The crimping process by the stitcher 20 can also be performed when the carcass material 3 is wound on the inner liner 1 and the reinforcing material 2 as shown in FIG.

  The inner periphery side green tire 5 molded as described above is removed from the molding drum 10 and transferred to another molding drum by a conveying device (not shown), and then swelled in a toroidal shape in the radial direction. A finished green tire is formed by assembling this to an outer peripheral side green tire (not shown) made of a belt material, a tread material or the like. At that time, the air between the reinforcing layer 2a and the carcass material 3 and the air between the reinforcing layer 2a and the inner liner 1 are between the inner side of the carcass material 3 and the inner liner 1 as described above. Since the air is discharged into the gap R4, no air pool is generated between the reinforcing layer 2a and the carcass material 3 and between the reinforcing layer 2a and the inner liner 1. In addition, the air existing in the gap R4 between the carcass material 3 and the inner liner 1 is discharged to the outside through the air vent hole of the carcass material 3 when the inner peripheral side green tire 5 is expanded in the radial direction. Is done.

  Thus, according to the tire molding method of the present embodiment, the difference R3 between the radius R1 of the small diameter portion 12 and the radius R2 of the large diameter portion 11 corresponding to the reinforcing layer 2a is 70% of the thickness B of the reinforcing layer 2a. Since a gap R4 is formed between the center side in the width direction of the carcass material 3 and the inner liner 1 by using the molding drum 10 formed 90% from the inner side, the reinforcing layer 2a and the carcass material 3 The air between the reinforcing layer 2a and the inner liner 1 can be discharged into the gap R4 between the carcass material 3 and the inner liner 1. As a result, air accumulation does not occur between the reinforcing layer 2a and the carcass material 3 and between the reinforcing layer 2a and the inner liner 1, so that the separation between the reinforcing layer 2a and the carcass material 3 or the reinforcing layer 2a While peeling from the inner liner 1 can be prevented reliably, the uniformity can be improved. It was confirmed that air accumulation occurred when the level difference R3 was between 100% and 90% of the thickness B1 of the reinforcing layer 2a, and air accumulation also occurred when the level difference R3 was 70% or less.

  In addition, after the inner liner 1 is wound around the forming drum 10, the diameter of the forming drum 10 is expanded to extend the circumference of the inner liner 1 and wind the reinforcing material 2. When the reinforcing material 2 is wound, the inner liner 1 is not loosened, and the winding work of the reinforcing material 2 can be easily performed.

  In this case, the diameter of the molding drum is expanded so that the peripheral length of the inner liner 1 is extended by approximately 4%, and the tension in the circumferential direction of the reinforcing member 2 is increased from 0.5% to 1% with respect to the inner liner 1. Thus, even after the diameter expansion of the forming drum is released and the inner liner 1 and the reinforcing material 2 are contracted, the contracting force of the reinforcing material 2 can be made larger than that of the inner liner 1, and the inner liner Peeling between 1 and the reinforcing material 2 can be reliably prevented. If the elongation rate of the inner liner 1 is larger than 4% in a state where the tension of the reinforcing material 2 is smaller than 0.5%, no wrinkles of the inner liner 1 are generated, but the air pool is increased with the increase in the elongation rate. It was confirmed that, when the elongation rate was made smaller than 4% in a state where the tension of the reinforcing material 2 was larger than 1%, no air accumulation occurred but wrinkles of the inner liner 1 increased.

  In addition, after the carcass material 3 is wound on the inner liner 1 and the reinforcing layer 2a, the carcass material 3 is sequentially crimped to the reinforcing layer 2a side from the both ends in the width direction by the stitcher 20 toward the center in the width direction. Therefore, the air between the reinforcing layer 2a and the carcass material 3 and the air between the reinforcing layer 2a and the inner liner 1 are surely discharged into the gap R4 between the center side in the width direction of the carcass material 3 and the inner liner 1. Therefore, it is possible to more reliably prevent the occurrence of air accumulation between the reinforcing layer 2a and the carcass material 3 and between the reinforcing layer 2a and the inner liner 1.

  Furthermore, since the air vent hole is formed at least in the width direction center side of the carcass material 3, not only between the reinforcing layer 2a and the carcass material 3 and between the reinforcing layer 2a and the inner liner 1, but also the carcass material 3 The air between the inner liner 1 and the inner liner 1 can also be reliably discharged to the outside, and the occurrence of air accumulation can be prevented throughout the inner peripheral side green tire 5.

  In the above embodiment, the carcass material 3 has a single layer, but the same effect can be obtained even when the carcass material 3 has two or more layers.

The front view of the forming drum which shows one Embodiment of this invention Partially sectional front view showing an inner periphery side green tire formed by a forming drum Front sectional view of the main part showing the molding process Front sectional view of the main part showing the molding process

  DESCRIPTION OF SYMBOLS 1 ... Inner liner, 2 ... Reinforcement material, 2a ... Reinforcement layer, 3 ... Carcass material, 5 ... Inner peripheral side green tire, 10 ... Molding drum, 11 ... Large diameter part, 12 ... Small diameter part.

Claims (1)

An inner liner is wound around the outer peripheral surface of the molding drum, and a reinforcing layer is formed by winding a belt-shaped reinforcing material around both ends of the inner liner in the width direction, and a carcass material is wound around the inner liner and the reinforcing layer, thereby expanding in the radial direction. In the tire molding method of molding the inner periphery side green tire before letting out,
Using a forming drum consisting of a small-diameter portion whose outer diameter is smaller than the center side in the width direction at both ends in the width direction corresponding to the reinforcing layer,
An air vent hole is formed at least in the width direction center side of the carcass material,
The carcass material and the reinforcing layer are sequentially crimped to the reinforcing layer and the inner liner side from the both ends in the width direction toward the center in the width direction,
A tire molding method comprising molding so that the difference in radius between the center side in the width direction of the molding drum and the small diameter portion is 70% to 90% of the thickness of the reinforcing layer.

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