JP4018413B2 - Manufacturing method of pneumatic radial tire - Google Patents

Description

試験の結果から、本発明の適用された実施例の空気入りラジアルタイヤは、空気残量不良率と騒音性能とを両立していることが分かる。
【００７４】
【発明の効果】
以上説明したように、本発明の空気入りラジアルタイヤの製造方法によれば、空気残留不良率と騒音性能とを両立した空気入りラジアルタイヤを効率的に製造できる、という優れた効果を有する。
【００７５】
【図面の簡単な説明】
【図１】 本発明による空気入りラジアルタイヤの左半分の断面図である。
【図２】 ベルト補強層の断面図である。
【図３】 形成途中のベルト補強層、及びストリップの断面図である。
【図４】 他の実施形態に係るストリップの断面図である。
【図５】 更に他の実施形態に係るストリップの断面図である。
【図６】 従来の螺旋巻きベルト補強層とトレッドゴムの断面図である。
【符号の説明】
１０ 空気入りラジアルタイヤ
１６ トレッド
１８ カーカス
２０ ビードコア
２１ ベルト
２２ ベルト補強層
２６ 補強コード
３０ 補強ゴムストリップ
３２ 被覆ゴム[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a pneumatic radial tire, and more particularly to a manufacturing method of a pneumatic radial tire having a spiral wound belt reinforcing layer on the belt.
[0002]
[Prior art]
In recent years, as a means for improving the wear resistance, high-speed durability, etc. of pneumatic radial tires, a spirally wound belt reinforcement layer using a reinforcing rubber strip in which a plurality of reinforcing cords are embedded in rubber in parallel in the width direction has been developed. A technique of arranging the crossing belt on the outer side or the inner side in the tire radial direction is known.
[0003]
For example, as a method of manufacturing a pneumatic radial tire in which a spirally wound belt reinforcing layer is disposed on the outer side in the tire radial direction of the crossing belt, a reinforcing rubber strip is spirally wound around the outer side in the radial direction of the crossing belt member formed in an annular shape, Further, a method of winding a tread strip on the outer side in the radial direction is generally applied.
[0004]
In the above manufacturing method, conventionally, a reinforced rubber strip having a cord driving density uniform in the width direction has been generally used.
[0005]
Further, with emphasis on the effect of suppressing the growth of the tire diameter of the spirally wound belt, the reinforcing rubber strip is wound in a spiral manner tightly in the width direction or with overlapping side edges.
[0006]
By the way, a tire having a spiral wound belt reinforcing layer in which a reinforcing rubber strip whose cord driving density is almost uniform in the width direction is wound tightly in the width direction or in a spiral shape with overlapping side edges, Although effective in improving high-speed durability, etc., since the rigidity as a belt package is increased, for example, cavity resonance easily occurs, which is disadvantageous in terms of noise improvement and the like.
[0007]
[Problems to be solved by the invention]
As a countermeasure, a method of optimizing the rigidity of the belt package by concentrating the gap between the side edges of the reinforced rubber strip in a spiral manner is conceivable . However, as shown in FIG. There is a problem that when the tread rubber 102 is wound around 100, air tends to remain in the gap 104 formed between the reinforcing rubber strip 100 and the reinforcing rubber strip 100.
[0008]
In view of the above facts, an object of the present invention is to provide a method for manufacturing a pneumatic radial tire that achieves both an air residual defect rate and noise performance.
[0009]
[Means for Solving the Problems]
[0010]
[0011]
[0012]
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
According to the first aspect of the present invention, there is provided a reinforcing rubber strip forming step in which a plurality of reinforcing cords are arranged in parallel to each other and covered with rubber to form a belt-shaped reinforcing rubber strip having a constant thickness in the width direction, and the reinforcing rubber A spiral wound belt reinforcing layer forming step of forming a spiral wound belt reinforcing layer by spirally winding the strip around at least one of the outer peripheral surface of the carcass and the outer peripheral surface of the belt, and forming a tread on the outermost surface by winding the tread rubber. A pneumatic radial tire manufacturing method having a tread forming step, wherein, in the reinforcing rubber strip manufacturing step, a driving density of the reinforcing cord in at least a part in a width direction of the reinforcing rubber strip is set to be higher than that of other portions. In the step of forming the spirally wound belt reinforcing layer, the reinforcing rubber strip is placed on the same side edge. Was close contact wound helically, is characterized by.
[0024]
Next, in the method for manufacturing a pneumatic radial tire according to claim 1 ,
First, in the reinforcing rubber strip forming step, a plurality of reinforcing cords are arranged in parallel to each other and covered with rubber to form a belt-like reinforcing rubber strip. In the reinforcing rubber strip manufacturing process, the reinforcing rubber strip is formed so that the reinforcing cord driving density in at least a part of the reinforcing rubber strip in the width direction is smaller than the other parts.
[0025]
In the spiral-wound belt reinforcing layer forming step, the reinforcing rubber strip is spirally wound with at least one of the side edges closely attached to the outer circumferential surface of the carcass and the outer circumferential surface of the belt to form a spiral-wound belt reinforcing layer. The
[0026]
In the tread forming step, tread rubber is wound to form a tread on the outermost surface.
[0027]
Here, when the spirally wound belt reinforcing layer is formed on the outer peripheral surface of the belt, the belt reinforcing layer is formed by winding the reinforcing rubber strip in a spiral shape with the side edges closely adhered to each other, so that air is interposed. Tread rubber can be wrapped without causing
[0028]
The same applies to the case where the belt is formed on the belt reinforcing layer, and the belt can be wound without interposing air.
[0029]
The reinforcing rubber strip has a reinforcing cord driven density in at least a part of the width direction set smaller than that of the other parts. Therefore, the reinforcing rubber strip is formed by spirally winding the reinforcing rubber strip with the side edges closely attached to each other. In the layer, a plurality of low density regions in which the density of the reinforcing cord in the tire width direction is partially reduced are provided at intervals in the tire width direction.
[0030]
Therefore, the rigidity of the belt reinforcing layer is appropriately reduced, the rigidity as the belt package can be optimized, and a pneumatic radial tire that can suppress the occurrence of cavity resonance is obtained.
[0031]
[0032]
Further, in the reinforcing rubber strip forming step, the reinforcing rubber strip is formed with a constant thickness in the width direction, so that a belt reinforcing layer having a constant thickness in the tire width direction can be formed. When the tread rubber is wound on the belt, or when the belt is wound on the spirally wound belt reinforcing layer, air can be surely not interposed in the tire.
[0033]
The invention of claim 2 is a method of manufacturing a pneumatic radial tire according to claim 1, in the reinforcing rubber strip forming process, the density of the reinforcing cords in the vicinity of at least one side edge of the other portion The reinforcing rubber strip is formed to be smaller than the driving density.
[0034]
3. The method of manufacturing a pneumatic radial tire according to claim 2, wherein in the reinforcing rubber strip forming step, the reinforcing rubber strip is formed such that the density of the reinforcing cords near at least one side edge is smaller than the driving density of the other part. Therefore, the low-density region in which the density of the reinforcing cord in the tire width direction is partially reduced by forming the reinforcing rubber strip in a spiral shape with the side edges closely contacting each other is reduced in the tire width direction. A plurality of places are provided at intervals.
[0035]
According to a third aspect of the present invention, in the method for manufacturing a pneumatic radial tire according to the second aspect, in the reinforcing rubber strip forming step, the density of the reinforcing cords near both side edges is higher than the driving density near the center. The reinforcing rubber strip is formed to be small.
[0036]
In the pneumatic radial tire manufacturing method according to claim 3 , in the reinforcing rubber strip forming step, the reinforcing rubber strip is formed so that the density of the reinforcing cords near the side edges is smaller than the driving density near the center. The reinforcing rubber strip is formed by spirally winding the side edges closely to each other, so that the low-density region in which the density of the reinforcing cord in the tire width direction is partially reduced is spaced apart in the tire width direction. Multiple places will be provided.
[0037]
According to a fourth aspect of the present invention, in the pneumatic radial tire manufacturing method according to the first or second aspect, in the reinforcing rubber strip forming step, the density of the reinforcing cords in the vicinity of the center is in the vicinity of both side edges. The reinforcing rubber strip is formed to be smaller than the driving density.
[0038]
According to the method for manufacturing a pneumatic radial tire according to claim 4 , in the reinforcing rubber strip forming step, the reinforcing rubber strip is formed so that the density of the reinforcing cord in the vicinity of the center is smaller than the driving density in the vicinity of both side edges. By doing so, a plurality of low density regions in which the density of the reinforcing cord in the tire width direction is partially reduced are provided at intervals in the tire width direction.
[0039]
According to a fifth aspect of the present invention, in the method for manufacturing a pneumatic radial tire according to any one of the first to fourth aspects, the tensile strength per reinforcing cord is 98 N or more. The reinforcing cord driving density in a portion having a high arrangement density is 30 to 60/50 mm.
[0040]
When the reinforcing cord driving density is less than 30/50 mm in the portion where the reinforcing cord is disposed at a high density, the hoop effect of the belt reinforcing layer of the pneumatic radial tire that is the product is insufficient.
[0041]
On the other hand, if the reinforcement cord driving density exceeds 60/50 mm in the portion where the reinforcement cord is disposed at a high density, the cord spacing is too narrow and adhesion between the cords by the coating rubber cannot be secured.
[0042]
Further, when the tensile strength per reinforcing cord is less than 98 N, even if the reinforcing cords are arranged densely, the hoop effect of the belt reinforcing layer is insufficient.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0044]
In FIG. 1, reference numeral 10 denotes a pneumatic radial tire. The pneumatic radial tire 10 includes a pair of bead portions 12 (one side is omitted in FIG. 1) and sides extending from the bead portions 12 toward the outside in a substantially radial direction. The wall portion 14 and a substantially cylindrical tread 16 that connects the outer ends in the radial direction of the sidewall portions 14 are provided.
[0045]
The pneumatic radial tire 10 is reinforced by a substantially toroidal carcass 18 extending from one bead portion 12 to the other bead portion 12, and both side portions in the width direction of the carcass 18 are bead portions 12. Are folded from the axially inner side toward the axially outer side around the bead cores 20 embedded therein.
[0046]
The carcass 18 is composed of at least one carcass ply, and a number of cords such as steel extending in a substantially radial direction are embedded in the carcass ply.
[0047]
A belt 21 is provided outside the carcass 18 in the radial direction. The belt 21 is formed by laminating at least one, in this case, two belt plies 21A and 21B each having a plurality of cords such as steel embedded therein. It is configured.
[0048]
The cords embedded in the belt plies 21A and 21B extend substantially linearly and incline so as to intersect the tire equatorial plane CL at a substantially constant angle A of 15 to 35 degrees. 21A and 21B are inclined in the opposite direction with respect to the tire equatorial plane CL and intersect each other.
[0049]
A belt reinforcement layer 22 that covers the belt 21 over its entire width is provided on the outer side in the tire radial direction of the belt 21.
[0050]
As shown in FIG. 2, the belt reinforcing layer 22 has a reinforcing cord 26 embedded in a covering rubber 24 that is continuous in the tire width direction and has a constant thickness in the tire width direction (arrow A direction). .
[0051]
Inside the belt reinforcing layer 22 of the present embodiment, a cord bundle 28 composed of a plurality of (four in the present embodiment) reinforcing cords 26 arranged in parallel with each other at regular intervals is spirally arranged.
[0052]
Here, the distance L ₂ between the cord bundles 28 is set sufficiently larger than the distance L ₁ between the reinforcing cords 26 inside the cord bundle 28.
(Manufacturing process of belt reinforcement layer)
Next, the manufacturing process of this belt reinforcement layer 22 is demonstrated. In addition, since it is a manufacturing process as usual about parts other than the belt reinforcement layer 22, the description is abbreviate | omitted.
[0053]
For example, the belt reinforcing layer 22 is formed in a spiral shape without gaps while a belt-shaped reinforcing rubber strip 30 having a constant width and thickness having a cross-sectional structure as shown in FIG. It is formed by winding.
[0054]
The reinforcing rubber strip 30 is formed by arranging a plurality of reinforcing cords 26 (four in this embodiment) 26 at a predetermined interval (L ₁ ) to form a cord bundle 28, and then covering rubber 32 by a conventionally known method. Is coated.
[0055]
In this reinforced rubber strip 30, portions (cord non-arranged portions) of only a 1/2 L ₂ width covering rubber 32 are provided on both sides of the cord bundle 28.
[0056]
Thus, the belt reinforcing layer 22 is formed by spirally winding the reinforcing rubber strip 30 having a constant width and a constant thickness on the belt 21 with the side edges closely contacting each other, so that the surface of the belt reinforcing layer 22 is formed. The tread 16 can be attached without leaving any air between the belt reinforcing layer 22 and the high-quality pneumatic radial tire 10 having no unnecessary air in the tread.
[0057]
The number of reinforcement cords 26 driven in the cord bundle 28 is preferably 30 to 60/50 mm. When the number of reinforcement cords 26 driven in the cord bundle 28 is less than 30/50 mm, the tagging effect as a spiral material is weakened. On the other hand, if the number of reinforcement cords 26 driven in the cord bundle 28 exceeds 60/50 mm, the cord spacing is too narrow and adhesion between the cords by the coating rubber cannot be secured.
[0058]
The ratio of the total width (L ₂ ) of the portion other than the cord bundle 28 (the rubber-only portion) to the width W of the reinforcing rubber strip 30 is preferably 20 to 70%.
[0059]
When the ratio of the total width (L ₂ ) of portions other than the cord bundle 28 to the width W of the reinforcing rubber strip 30 is less than 20%, the vibration damping effect is insufficient.
[0060]
On the other hand, if the ratio of the total width (L ₂ ) of the portion other than the cord bundle 28 to the width W of the reinforcing rubber strip 30 exceeds 70%, the tagging effect as a spiral material is weakened.
[0061]
Since the material of the reinforcing cord 26 is lightweight while ensuring strength, organic fibers, particularly nylon, aramid, PET, PEN, and the like are suitable.
[0062]
In the pneumatic radial tire 10 of the present embodiment, the reinforcing cord 26 of the belt reinforcing layer 22 is spirally wound, and the reinforcing cord 26 with respect to the tire circumferential direction extends substantially along the tire circumferential direction. Is strong, the elongation of the belt 21 during tire rotation can be suppressed, and the high-speed durability can be improved.
[0063]
Further, since a plurality of portions of the reinforcing cord 26 having a low arrangement density in the tire width direction are provided at intervals in the tire width direction of the belt reinforcing layer 22, a conventional belt reinforcement in which the arrangement density is set uniformly in the tire width direction. It is harder to vibrate than the layer, and the occurrence of cavity resonance can be suppressed.
(Other embodiments)
In the reinforcing rubber strip 30 of the above embodiment, the cord bundle 28 is disposed at the center in the width direction of the reinforcing rubber strip 30, but may be disposed closer to one side as shown in FIG. As such, it may be divided into left and right.
[0064]
[0065]
Further, the number of the reinforcing cords 26 included in the reinforcing rubber strip 30 may be other than four.
(Test example)
In order to confirm the effect of the present invention, two types of pneumatic radial tires (conventional examples 1 and 2) manufactured by the conventional method and one type of pneumatic radial tire (example) manufactured by the method of the present invention are prepared. Comparison of the residual air failure rate in the tread and the noise performance were performed.
[0066]
Air residual defect rate: This is the rate of occurrence determined by tire appearance inspection, and at the time of tire appearance inspection, the air accumulation occurrence part was visually inspected and touched (touched by hand). Tires with air pockets at one location were evaluated as defective.
[0067]
Noise performance: A 195 / 65R15 tire was mounted on a 6JJ × 15 rim, and was run on a 6m diameter drum (the outer circumference was a pseudo rough road) at an internal pressure of 200kPa, a load of 4.0kN, and a speed of 60km / h. The tire axial force at the time was measured.
[0068]
The tire axial force is a test method that can be evaluated as synonymous with tire indirect sound, and 180 to 280 Hz, which is the same band, was evaluated.
[0069]
A value with a minus sign indicates that the noise is reduced with reference to Conventional Example 2.
-Example tire: The pneumatic radial tire described in the above embodiment. The reinforced rubber strip had a width of 6 mm and a thickness of 0.72 mm. In the reinforcing rubber strip, four reinforcing cords were arranged at the central portion with an interval (L ₁ ) of 0.5 mm. The reinforcing rubber strip was spirally wound on the belt with the side edges closely attached.
Tire of Conventional Example 1: The reinforced rubber strip had a width of 6 mm and a thickness of 0.72 mm. Further, six reinforcing cords were embedded in the reinforcing rubber strip with an interval (L ₁ ) of 0.5 mm. The reinforcing rubber strip was spirally wound on the belt while leaving a gap (3 mm) in the tire width direction.
-Tire of Conventional Example 2: A reinforced rubber strip similar to that of Conventional Example 1 was used, and the belt was spirally wound with the side edges closely attached.
[0070]
The pneumatic radial tires of Examples and Conventional Examples 1 and 2 used nylon 66 (1400 dtex / 2) cords as reinforcement cords.
[0071]
In the pneumatic radial tires of Examples and Conventional Examples 1 and 2, two belt plies including steel cords inclined at 24 degrees with respect to the tire circumferential direction are stacked so that the cords cross each other. It has a combined cross belt layer.
[0072]
The air residual failure rate and noise performance of the pneumatic radial tires of Examples and Conventional Examples 1 and 2 are as described in Table 1 below.
[0073]
[Table 1]

From the test results, it can be seen that the pneumatic radial tire according to the embodiment to which the present invention is applied has both a remaining air remaining rate and noise performance.
[0074]
【The invention's effect】
As described above, according to the method for manufacturing a pneumatic radial tire of the present invention, there is an excellent effect that it is possible to efficiently manufacture a pneumatic radial tire having both a residual air defective rate and a noise performance.
[0075]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a left half of a pneumatic radial tire according to the present invention.
FIG. 2 is a cross-sectional view of a belt reinforcing layer.
FIG. 3 is a cross-sectional view of a belt reinforcing layer and a strip that are being formed.
FIG. 4 is a cross-sectional view of a strip according to another embodiment.
FIG. 5 is a cross-sectional view of a strip according to yet another embodiment.
FIG. 6 is a cross-sectional view of a conventional spirally wound belt reinforcing layer and tread rubber.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pneumatic radial tire 16 Tread 18 Carcass 20 Bead core 21 Belt 22 Belt reinforcement layer 26 Reinforcement cord 30 Reinforcement rubber strip 32 Cover rubber

Claims (5)

Reinforcing rubber strip forming step of forming a belt-shaped reinforcing rubber strip having a plurality of reinforcing cords arranged in parallel with each other and covered with rubber to have a constant thickness in the width direction ;
A spirally wound belt reinforcing layer forming step of forming a spirally wound belt reinforcing layer by spirally winding the reinforcing rubber strip around at least one of the outer peripheral surface of the carcass and the outer peripheral surface of the belt;
A tread forming step of winding tread rubber to form a tread on the outermost surface;
A method for producing a pneumatic radial tire having
In the reinforcing rubber strip manufacturing process, the driving density of the reinforcing cord in at least a part of the reinforcing rubber strip in the width direction is set to be smaller than other parts,
In the spiral wound belt reinforcing layer forming step, the reinforcing rubber strip is wound spirally with the side edges closely contacting each other. In the reinforcing rubber strip forming process, according to claim 1, wherein at least the density of the reinforcing cords of one side edge vicinity portion forming the reinforcing rubber strip to be smaller than the driving density of the other portions, it The manufacturing method of the pneumatic radial tire of description . 3. The air according to claim 2, wherein, in the reinforcing rubber strip forming step, the reinforcing rubber strip is formed so that a density of the reinforcing cords near both side edges is smaller than a driving density near the center. A manufacturing method of a radial tire. Wherein the reinforcing rubber strip forming process, the density of the reinforcing cords in the vicinity of the center to form the reinforcing rubber strip to be smaller than the implantation density near both side edges, claim 1 or claim 2, characterized in that The manufacturing method of the pneumatic radial tire of description . The tensile strength per reinforcing cord is 98N or more,
5. The pneumatic radial tire according to claim 1, wherein a driving density of the reinforcing cords in a portion where the reinforcing cords are arranged at a high density is 30 to 60 pieces / 50 mm. Production method.

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