JP4316524B2 - Pneumatic tire manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a pneumatic tire provided with a belt-reinforcement layer having a jointless structure. More specifically, the present invention greatly increases productivity and prevents deterioration of radial force variation (RFV). The present invention relates to a method for manufacturing a pneumatic tire.

  In some pneumatic tires, a belt reinforcing layer having a jointless structure in which a strip material including a plurality of reinforcing cords is spirally wound in the tire circumferential direction is provided on the outer peripheral side of the belt layer in the tread portion.

  When forming a belt reinforcing layer having such a jointless structure, a strip material is supplied from a winding head onto a forming drum, and the tightening force by the belt reinforcing layer is set based on the laminated structure of the strip material. For example, the strip material is double wound in the central region of the tread portion, while triple winding is performed in the edge region of the belt layer.

  In general, the strip material is wound by a single winding head. In this case, however, the winding process requires a lot of time and has a disadvantage of poor productivity. For this reason, it has been proposed that two strip members are simultaneously wound around a forming drum using two winding heads (see, for example, Patent Document 1 and Patent Document 2).

  However, when a belt reinforcing layer with a jointless structure is formed using two winding heads and the laminated structure of the strip material is changed according to the position in the tire width direction, the overlapping condition of the strip material is complicated on the tire circumference. Will change. For example, the strip material is slightly inclined with respect to the tire circumferential direction, but such an inclination slightly affects the overlapping state of the strip materials. And, if the portion where the strip material is triple wrapped is unevenly present on the tire circumference, the fluctuation of the rigidity of the belt reinforcing layer on the tire circumference will increase, and the radial force variation will deteriorate. There is.

For this reason, when forming a jointless belt reinforcement layer using two winding heads, the radial force variation can be made worse by making the portion where the strip material is triple wound uniform on the tire circumference. It is desired to prevent it.
Japanese Patent No. 2639703 JP-A-8-142226

An object of the present invention is to provide a method for manufacturing a pneumatic tire that significantly increases productivity and prevents deterioration of radial force variation.

In order to achieve the above object, a pneumatic tire manufacturing method according to the present invention includes a strip material including a plurality of reinforcing cords spirally wound in the tire circumferential direction on the outer peripheral side of a belt layer in a tread portion. In the method of manufacturing a pneumatic tire provided with a belt-reinforcing layer having a jointless structure in which the material is double-wound in the center region of the tread portion and triple-wound in the edge region of the belt layer,
When forming the belt reinforcing layer on the forming drum, the two strip materials are respectively supplied from the individual winding heads to the forming drum, and the belt is reinforced by the ½ width of the strip material from both edge positions of the belt reinforcing layer. Starting from the position shifted to the center side of the layer, the strip material is simultaneously wound around the forming drum toward the center side of the belt reinforcing layer, and these strip materials are crossed with each other at the center of the belt reinforcing layer to further reinforce the belt. A method of controlling the amount of wrapping rotation of the strip material at the folded portion at both edge positions of the layer,
When the total width of the belt reinforcing layer is divisible by the width of the strip material, the winding rotation amount θ of the strip material at the folded portion is in a range of 360 ° × n + 150 ° ≦ θ ≦ 360 ° × n + 210 ° (n: (Integer).

  In the present invention, when forming the belt reinforcing layer on the forming drum using two winding heads, the belt reinforcing layer is formed by removing the two strip members from the both edge positions of the belt reinforcing layer by ½ width of the strip member. Wrapped around the forming drum at the same time toward the center of the belt reinforcement layer, starting from the position shifted to the center of the belt, crossing each other at the center of the belt reinforcement layer, and further the positions of both edges of the belt reinforcement layer Use a winding method that wraps in the opposite direction. Thereby, productivity can be significantly improved compared with the case where a belt reinforcement layer is shape | molded using a single winding head.

  Here, when the total width of the belt reinforcing layer is divisible by the width of the strip material, the winding rotation amount θ of the strip material at the folded portion is set in a range of 360 ° × n + 150 ° ≦ θ ≦ 360 ° × n + 210 °. That is, the number of rotations of the strip material wound at the folded portion is substantially n + 1/2. By carrying out such control, the portion where the strip material is triple wrapped is made uniform on the tire circumference, the fluctuation of the rigidity of the belt reinforcement layer on the tire circumference is minimized, and the radial force variation is deteriorated. Can be prevented.

  The above control method is most effective when the remainder when the total width of the belt reinforcing layer is divided by the width of the strip material is 0, but the remainder is not more than 0.05 times the width of the strip material or 0. The present invention can also be applied to the case of 95 times or more. The width of the strip material referred to here is a width measured in the drum axis direction (tire axis direction) in a state where the strip material is wound.

  In the present invention, it is preferable that the winding start positions of the two strip members are different from each other in the drum circumferential direction, and the deviation amount of the winding start positions is set in a range of 30 ° to 60 ° around the drum shaft. When the winding start positions of the two strip materials are set as described above, the overlapping state of the strip materials can be optimized.

  According to the present invention, by the above manufacturing method, a strip material including a plurality of reinforcing cords is spirally wound in the tire circumferential direction on the outer peripheral side of the belt layer in the tread portion, and the strip material is wound in the central region of the tread portion. Then, a pneumatic tire is provided that includes a belt-reinforcing layer having a jointless structure in which double winding is performed while triple winding is performed in the edge region of the belt layer, and the strip material is provided with a predetermined winding structure. Such a pneumatic tire has excellent productivity and good uniformity.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a pneumatic tire according to an embodiment of the present invention. In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A carcass layer 4 is mounted between the pair of left and right bead portions 3 and 3, and an end portion of the carcass layer 4 is folded around the bead core 5 from the inside to the outside of the tire. On the outer peripheral side of the carcass layer 4 in the tread portion 1, two belt layers 6 are disposed over the entire circumference of the tire. These belt layers 6 include reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged such that the reinforcing cords cross each other between the layers. On the outer peripheral side of the belt layer 6, a strip material including a plurality of reinforcing cords arranged in the longitudinal direction is spirally wound in the tire circumferential direction, and the strip material is wound twice in the central region of the tread portion 1. On the other hand, in the edge region of the belt layer 6, a belt-reinforcing layer 7 having a jointless structure with triple winding is disposed.

  2 and 3 schematically show a belt reinforcing layer forming apparatus. 2 and 3, the forming drum 11 is configured so as to be expandable / contractable in the radial direction and to rotate around the central axis. Two winding heads 12 and 12 are disposed in the vicinity of the forming drum 11. The winding heads 12 and 12 are arranged at positions shifted from each other in the circumferential direction of the forming drum 11 and are configured to reciprocate in the axial direction of the forming drum 11. The configuration of the winding heads 12 and 12 is not particularly limited as long as the strip material S including a plurality of reinforcing cords is continuously supplied onto the forming drum 11. The belt-reinforcing layer 7 having a jointless structure is formed by forming the belt layer 6 on the forming drum 11 and then winding the strip material S on the belt layer 6 and winding the strip material S according to the position in the drum axial direction. It is molded by changing

  FIG. 4 shows a method of winding a strip material according to an embodiment of the present invention. FIG. 4 shows a state in which a belt reinforcing layer for one round of the tire (0 ° to 360 °) is developed and stretched in the drum axial direction in order to facilitate understanding of the present invention.

In FIG. 4, the two strip materials S _A and S _B have the same width, and are respectively supplied from the individual winding heads onto the forming drum. E _A1 is beginning, E _A2 of the strip material S _A termination, E _B1 of the strip material S _A is the starting end of the strip material S _B, E _B2 is the end of the strip material S _B. Strip material S _A is formed toward the other edge position Y of the belt reinforcing layer position displaced from one edge position X of the belt reinforcing layer in the center side of the one half width belt reinforcing layer of the strip material as a starting point It is wound around the drum and folded back in the opposite direction at the other edge position Y of the belt reinforcing layer. Strip material S _B is formed toward a position displaced from the other edge position Y of the belt reinforcing layer in the center side of the one half width belt reinforcing layer of the strip material at one edge position X of the belt reinforcing layer as a starting point The belt is wound around the drum and folded in the opposite direction at one edge position X of the belt reinforcing layer. The strip materials S _A and S _B are wound simultaneously.

The winding start positions of the two strip materials S _A and S _B are different from each other in the drum circumferential direction, and the deviation amount of the winding start position is set in the range of 30 ° to 60 ° around the drum shaft. . In Figure 4, the deviation amount of winding start position of the strip material S _A for winding start position of the strip material S _B is set to + 60 °.

The strip material S _A, when the winding of S _B, the folded-back portion W _A, the strip material in the W _B S _A, rotating winding amount of S _B is controlled. The folded portions W _A and W _B are portions from when the strip materials S _A and S _B are folded in the opposite direction at the edge position of the belt reinforcing layer to the end. Here, when the total width of the belt reinforcing layer is divisible by the width of the strip materials S _A and S _B , for example, the total width of the belt reinforcing layer is 220 mm and the width of the strip materials S _A and S _B is 10 mm. At a certain time, the winding amount θ of winding of the strip material at the folded portions W _A and W _B is set to a range of 360 ° × n + 150 ° ≦ θ ≦ 360 ° × n + 210 ° (n: integer). However, the integer n is selected from the range of 1-5. In this embodiment, the folded-back portion W _A, the strip material in the W _B S _A, rotational speed winding of S _B has a 2.5 rotation (θ = 900 °).

In FIG. 4, the shaded portion is a portion where the strip materials S _A and S _B are triple-wrapped, the mesh portion is a portion where the strip materials S _A and S _B are a single layer, and the other portions are strips. This is the portion where the materials S _A and S _B are double wound. As described above, the overlapping state of the strip materials S _A and S _B changes in a complicated manner on the tire circumference.

  FIG. 5 shows the total width of the portion of the belt reinforcing layer shown in FIG. 4 where the strip material is triple-rolled and the portion where it is a single layer, added for each position in the tire circumferential direction. As shown in FIG. 5, the total width of the portion where the strip material is wound three times is substantially uniform on the tire circumference. In addition, when the number of rotations of the strip material at the turn-up portion is two, the total width of the portion where the strip material is triple-wound becomes nonuniform on the tire circumference as shown by the broken line in FIG. The strip material winding speed at the turn-up portion does not need to be strictly 2.5 rotations, and a variation in the range of ± 30 ° can be allowed. If it deviates from this allowable range, the uniformity on the tire circumference of the portion where the strip material is triple wound becomes insufficient.

FIG. 6 shows a strip material winding method according to another embodiment of the present invention. FIG. 6 shows a state in which a belt reinforcing layer for one round of the tire (0 ° to 360 °) is developed and stretched in the drum axial direction in order to facilitate understanding of the present invention. In the present embodiment, the winding start positions of the strip materials S _A and S _B are only different from those in the above-described embodiment. Therefore, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted. In Figure 6, the deviation amount of winding start position of the strip material S _A for winding start position of the strip material S _B is set to -60 °.

In this embodiment, the strip material S _A, when the winding of S _B, the folded-back portion W _A, the strip material in the W _B S _A, the rotation amount winding of S _B is controlled. That is, the total width of the strip material S _A of the belt reinforcing layer, when in relation divisible by the width of the S _B, the folded-back portion W _A, 360 ° rotation amount theta winding of strip material in the _{W B × n + 150 ° ≦} θ ≦ 360 The range is ° × n + 210 ° (n: integer). In this embodiment, the folded-back portion W _A, the strip material in the W _B S _A, rotational speed winding of S _B has a 2.5 rotation (θ = 900 °).

In FIG. 6, the shaded portion is a portion where the strip materials S _A and S _B are triple wound, the mesh portion is a portion where the strip materials S _A and S _B are a single layer, and the other portions are strips. This is the portion where the materials S _A and S _B are double wound. As described above, the overlapping state of the strip materials S _A and S _B changes in a complicated manner on the tire circumference.

  FIG. 7 shows the total width of the portion of the belt reinforcing layer shown in FIG. 6 where the strip material is triple wound and the portion where the strip material is a single layer added for each position in the tire circumferential direction. As shown in FIG. 7, the total width of the portion where the strip material is wound three times is substantially uniform on the tire circumference. In addition, when the number of rotations of the strip material at the turn-up portion is two, the total width of the portion where the strip material is triple-wound becomes nonuniform on the tire circumference as shown by the broken line in FIG. The strip material winding speed at the turn-up portion does not need to be strictly 2.5 rotations, and a variation in the range of ± 30 ° can be allowed.

  As described above, when forming a belt-reinforcing layer having a jointless structure using two winding heads, the portion where the strip material is wound in three layers is made uniform on the tire circumference, so that Deterioration of force variation can be prevented. Of course, the belt reinforcing layer can be efficiently formed using two winding heads.

It is a meridian half section view showing a pneumatic tire according to an embodiment of the present invention. It is a top view which shows the shaping | molding apparatus of the belt reinforcement layer used by this invention. It is a side view which shows the shaping | molding apparatus of the belt reinforcement layer used by this invention. It is an expanded view which shows the winding method of the strip material which consists of embodiment of this invention. FIG. 5 is a graph showing the total width of a portion where the strip material is triple wound and a portion where the strip material is a single layer in the belt reinforcing layer shown in FIG. 4 for each position in the tire circumferential direction. It is an expanded view which shows the winding method of the strip material which consists of other embodiment of this invention. 7 is a graph showing the total width of a portion in which the strip material is triple wound and a single layer in the belt reinforcing layer shown in FIG. 6 added for each position in the tire circumferential direction.

Explanation of symbols

1 tread portion 2 sidewall portion 3 bead portion 4 carcass layer 5 bead core 6 belt layer 7 belt reinforcing layer 11 forming drum 12 wound head S, S _A, S _B strip material W _A, W _B folded portion X, Y belt reinforcing layer Edge position

Claims (2)

A strip material including a plurality of reinforcing cords is spirally wound in the tire circumferential direction on the outer peripheral side of the belt layer in the tread portion, and the strip material is double-wrapped in the central region of the tread portion, while the belt layer In the method of manufacturing a pneumatic tire provided with a belt-reinforcement layer having a jointless structure that is triple wound in the edge region,
When forming the belt reinforcing layer on the forming drum, the two strip materials are respectively supplied from the individual winding heads to the forming drum, and the belt is reinforced by ½ width of the strip material from both edge positions of the belt reinforcing layer. Starting from the position shifted to the center side of the layer, the strip material is simultaneously wound around the forming drum toward the center side of the belt reinforcing layer, and these strip materials are crossed with each other at the center of the belt reinforcing layer to further reinforce the belt. A method of controlling the amount of wrapping rotation of the strip material at the folded portion at both edge positions of the layer,
When the total width of the belt reinforcing layer is divisible by the width of the strip material, the winding rotation amount θ of the strip material at the folded portion is in a range of 360 ° × n + 150 ° ≦ θ ≦ 360 ° × n + 210 ° (n: A method for producing a pneumatic tire, characterized in that it is an integer).   The pneumatic tire according to claim 1, wherein the winding start positions of the two strip members are different from each other in the drum circumferential direction, and the deviation amount of the winding start position is set in a range of 30 ° to 60 ° around the drum shaft. Production method.

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