JP4333839B2 - Method for manufacturing carcass material for pneumatic tire and pneumatic tire - Google Patents

Description

表１から、本発明タイヤの方法で得られたカーカス材を用いた空気入りタイヤは、ＬＦＶとＲＦＶを共に改善することができ、ユニフォミティを向上できることがわかる。
【００３６】
【発明の効果】
上述したように本発明は、補強コードをタイヤ周方向に対して９０°より小さい角度で配列したカーカス層に使用する空気入りタイヤ用カーカス材を製造する際に、上述した式を満足する幅を有するストリップ材を用いて製造することにより、多品種少量生産を可能にし、かつカーカス材のストックスペースを削減することができ、更にユニフォミティの向上が可能になる。
【図面の簡単な説明】
【図１】本発明の空気入りタイヤ用カーカス材の製造方法で得られたカーカス材を用いて製造した空気入りタイヤの一実施形態を示すタイヤ子午線要部断面図である。
【図２】本発明の空気入りタイヤ用カーカス材の製造方法を示す説明図である。
【図３】図２で得られたカーカス材の正面図である。
【図４】カーカス材に使用するストリップ材の断面図である。
【符号の説明】
１ トレッド部 ２ サイドウォール部
３ ビード部 ４ カーカス層
１５ 成形ドラム １６ ストリップ材
１６ａ 端面 １６ｂ 巻き付け開始端
１６ｃ 巻き付け終端 １７ 筒状カーカス材
２０ カーカス材 Ｆ ドラム軸
Ｌ カーカス材の長さ Ｗ 成形ドラムの周長
Ｙ カーカス材の幅 ｆ 補強コード
ｋ 未加硫ゴム ｘ ストリップ材の幅
α 巻き付け角度 α’所望の巻き付け角度[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for manufacturing a carcass material for a pneumatic tire and a pneumatic tire, and more particularly, manufacturing a carcass material for a pneumatic tire that is suitable for high-mix low-volume production and can reduce the stock space of the carcass material. The present invention relates to a method and a pneumatic tire manufactured using a carcass material manufactured by the method.
[0002]
[Prior art]
For a pneumatic radial tire provided with a carcass layer in which reinforcing cords extending in the tire width direction in the rubber layer are arranged at 90 ° with respect to the tire circumferential direction, a so-called full radial tire, the reinforcing cord is arranged in the tire circumferential direction. On the other hand, there is a so-called half-radial tire provided with a carcass layer arranged at an angle smaller than 90 °.
[0003]
The carcass material used for the carcass layer of such a half-radial pneumatic tire has a length corresponding to the width of the carcass layer of a long strip-like sheet material in which a number of aligned reinforcing cords are covered with rubber through a calendar roll. Bias cutting is performed sequentially, and the bias-cut sheet pieces are sequentially joined in the width direction (see, for example, Patent Document 1).
[0004]
The carcass material joined and formed in the shape of a long belt is wound and stocked on a winding roll, and is unwound from the winding roll and cut into a predetermined length when in use.
[0005]
[Patent Document 1]
JP-A-4-182119
[Problems to be solved by the invention]
The carcass material manufacturing method described above is suitable for mass production of tires by producing a long strip-shaped carcass material in advance and cutting and using it at the time of use. . In addition, there is a problem that a large space for stocking the carcass material wound on the winding roll is required.
[0007]
An object of the present invention is to provide a method for manufacturing a carcass material for a pneumatic tire and a pneumatic tire that are suitable for high-mix low-volume production and can reduce the stock space of the carcass material.
[0008]
[Means for Solving the Problems]
The method for producing a carcass material for a pneumatic tire according to the present invention that achieves the above object includes a reinforcing cord extending in the tire width direction at an angle smaller than 90 ° with respect to the tire circumferential direction in the rubber layer along the tire circumferential direction. A method of manufacturing a carcass material for a pneumatic tire used for a carcass layer arranged at a predetermined interval, wherein the reinforcing cord is not added on a forming drum having a circumferential length W corresponding to the width of the carcass material. While the strip material coated with vulcanized rubber is brought into contact with the end surfaces of adjacent strip materials at a winding angle α smaller than 90 ° with respect to the drum circumferential direction, only a predetermined length corresponding to the length L of the carcass material is obtained. When forming a cylindrical carcass material by winding it spirally, the cylindrical carcass material is formed using a strip material having a width x satisfying the following formulas (1) and (2), and then the cylindrical carcass material is formed. The scan material through the winding starting end of the strip material, and characterized by being cut along a line parallel to the drum axis.
[0009]
x = W · tan (90−α) (1)
L / x = integer (2)
The pneumatic tire according to the present invention is manufactured using the carcass material manufactured by the method for manufacturing a pneumatic tire carcass material.
[0010]
According to the present invention described above, by forming the carcass material as described above using the strip material having the width x satisfying the expressions (1) and (2), the uniformity is not adversely affected. Since a variety of products can be produced in small quantities and can be manufactured as needed, the stock space can be reduced.
[0011]
In addition, the conventional carcass material that has been joined and formed into a long band shape is joined by overlapping the ends of the sheet pieces that have been bias-cut, so there are a number of places where there are steps in rigidity, and when joining Due to the joining accuracy of the equipment used for the above, it is inevitable that there will be some deviation in the width direction, and it is inevitable that the uniformity will be reduced. However, the carcass material formed by winding the strip material as described above is Since there is no place, it is possible to improve uniformity.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of a pneumatic tire manufactured using a carcass material manufactured by the method of the present invention, where 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion.
[0013]
On the inner side of the tire, a carcass layer 4 is mounted between the left and right bead portions 3, and both end portions thereof are folded back from the inner side of the tire so that bead fillers 6 are sandwiched around bead cores 5 embedded in the bead portion 3. It is.
[0014]
In the carcass layer 4, reinforcing cords (not shown) that are inclined at an angle smaller than 90 ° with respect to the tire circumferential direction and extend in the tire width direction are arranged in the rubber layer at predetermined intervals along the tire circumferential direction. It has a structure. A belt layer 7 is provided on the outer peripheral side of the carcass layer 4 of the bead portion 1.
[0015]
A cap tread rubber layer 9 is disposed on the outer peripheral side of the belt layer 7 via an undertread rubber layer 8, and an inner liner layer 11 is provided on the inner side of the carcass layer 4. Outside the carcass layer 4, a bead cushion rubber layer 12 is disposed in the bead portion 3, and a side rubber layer 13 is disposed in the sidewall 2.
[0016]
The method for producing a carcass material for a pneumatic tire according to the present invention produces a carcass material used for the carcass layer 4 and will be described below with reference to FIGS.
[0017]
In manufacturing the carcass material, as shown in FIG. 2, the circumference W corresponding to the width Y of the carcass material 20 (see FIG. 3) corresponding to one layer of the carcass layer 4 (W = πD: where D is A forming drum 15 having a drum diameter) is used. As the molding drum 15, an expansion / contraction molding drum that can change the circumferential length W is preferably used, whereby various carcass materials 20 having different sizes can be manufactured by one molding drum.
[0018]
As shown in FIG. 4, a strip material 16 in which a reinforcing cord f is coated with unvulcanized rubber k as shown in FIG. 4 is adjacent to the molding drum 15 at a winding angle α smaller than 90 ° with respect to the drum circumferential direction. The cylindrical carcass material 17 is molded by spirally winding the molding drum 15 while rotating the molding drum 15 by a predetermined length corresponding to the length L of the carcass material 20 while contacting the end surfaces 16a of the materials 16 without gaps.
[0019]
At that time, a cylindrical carcass material 17 is formed using a strip material 16 having a width x that satisfies the following expressions (1) and (2).
[0020]
x = W · tan (90−α) (1)
L / x = integer (number of windings) (2)
The method of determining the width x of the strip material 16 according to the above formula is performed as follows. First, a desired winding angle α ′ is set in advance, and the width x of the strip material 16 is calculated by the equation (1) with the desired winding angle α ′ as the winding angle α. Next, when the value obtained by the expression (2) using the calculated value of the width x is an integer, the value calculated by the expression (1) is set as the width x of the strip material 16 and a desired winding angle is obtained. Let α ′ be the winding angle α.
[0021]
When the value obtained by equation (2) becomes a decimal, the first decimal place is rounded down or adjusted to an integer, and the value obtained from equation 2 using equation (2) is stripped. The width x of the material 16 is set, and the winding angle α is calculated from the value of the obtained width x using the formula (1), and the winding is performed at the winding angle α.
[0022]
More specifically, in the case of manufacturing the carcass material 20 having the desired winding angle α ′ of the strip material 16 of 82 °, the width Y of 595 mm, and the length L of 1540 mm, the winding angle α is first set to 82 °. From (1) x = 595 × tan (90-82)
= 83.6mm (rounded to the first decimal place)
Therefore, the value of the width x of the strip material 16 is 83.6 mm. Substituting this value into equation (2) gives
1540 / 83.6 = 18.4 (rounded to the first decimal place)
The value of equation (2) indicates the number of windings of the strip material 16, and when this value becomes a decimal number instead of an integer, when the winding start end 16b and the winding end 16c of the strip material 16 are viewed from the drum axis F direction. The resulting carcass material 20 is not in the shape of a parallelogram as shown in the figure and is partially missing, which adversely affects the tire uniformity. Therefore, the number of windings must be an integer.
[0023]
Therefore, when the number becomes decimal as described above, the first decimal place is rounded down or rounded up to make an integer. Rounding off or rounding up is selected so that the difference between the calculated winding angle α and the desired winding angle α ′ is within 1 °. Either of them may be selected as long as the difference is within 1 °, but it is preferable to select the one having a smaller difference.
[0024]
In the above example, it is rounded down to 18 (the number of windings after adjustment). When the width x of the strip material 16 is obtained from the value 18 using the formula (2),
x = 1540/18 = 85.6 mm (rounded to the first decimal place)
This obtained value of 85.6 mm is taken as the width x (adjusted width) of the strip material 16. The winding angle α is obtained from the value of the width x using the formula (1).
[0025]
85.6 = 595 × tan (90−α)
tan (90−α) = 85.6 / 595
α = 81.8 ° (rounded to one decimal place)
This obtained angle is defined as a winding angle α.
[0026]
After forming the cylindrical carcass material 17 as described above, the cylindrical carcass material 17 is cut along a line parallel to the drum axis F through the winding start end 16 b of the strip material 16. Thereby, the carcass material 20 shown in FIG. 3 can be obtained.
[0027]
The carcass material 20 formed in this way is wound on an inner liner material wound on a tire forming drum in the same manner as a conventional carcass material by a conventionally known tire manufacturing method, and finally. A green tire shown in FIG. 1 can be manufactured by molding a green tire and vulcanizing the green tire.
[0028]
According to the above-described present invention, the carcass material 20 is formed as described above using the strip material 16 having the width x satisfying the expressions (1) and (2) without adversely affecting the uniformity. Since it can cope with small-lot production of various varieties and can be manufactured as necessary, it may cause a problem that requires a large space for stocking the carcass material wound up on the winding roll. Absent.
[0029]
In addition, the conventional carcass material that has been joined and formed into a long band shape has many parts that have steps in rigidity because the ends of bias-cut sheet pieces are overlapped and joined. It is joined in a state slightly deviated in the width direction due to the mechanical accuracy at the time, and a decrease in uniformity due to it is inevitable, but the carcass material 20 formed by winding the strip material 16 as described above is not joined, There is no reduction in uniformity due to joining, and therefore uniformity can be improved.
[0030]
In the present invention, the winding angle α is preferably in the range of 70 ° to 88 °. When the winding angle α is greater than 88 °, the performance as a half radial tire cannot be obtained. Conversely, if it is smaller than 70 °, the difference between the winding angle α calculated after the adjustment and the desired winding angle α ′ becomes large, which is not preferable.
[0031]
In the embodiment described above, the peripheral length W of the forming drum is made to correspond to the width Y of the carcass material 20 in order to manufacture the carcass material 20 corresponding to one carcass layer 4. However, the carcass material 20 may correspond to a plurality of carcass layers. In this case, the carcass material has a width corresponding to the plurality of carcass layers, and thus has a circumferential length W corresponding to the width. Use a drum.
[0032]
【Example】
Table 1 shows a desired wrapping angle α ′ using a molding drum having a width Y of 600 mm, a length L of 1500 mm, and a circumferential length W of 600 mm (drum diameter: 191.1 mm). Twenty pieces of each of the changed carcass materials (Examples 1, 2, and 3) were produced from the strip materials having the width x obtained by the above procedure. Table 1 also shows the width x, the number of windings, and the winding angle α of the strip material obtained by the procedure. In addition, a 30 m long strip-shaped carcass material (21 joining locations) is manufactured by joining the sheet pieces bias-cut by the conventional method, and 20 carcass materials (conventional example) are obtained by cutting the strip. It was.
[0033]
Using each of these carcass materials, 20 test tires each having the configuration shown in FIG. 1 were manufactured with a common tire size of 225 / 60R17.
[0034]
When each of these test tires was subjected to an evaluation test of LFV (Lateral Force Variation) and RFV (Radial Force Variation) by the method shown below, the results shown in Table 1 were obtained. Table 1 also shows the amount of variation in the width dimension of the obtained carcass material (average of 20 sheets).
LFV and RFV
Each test tire was mounted on a rim having a rim size of 17 × 61/2, the air pressure was set to 180 kPa, and LFV and RFV were measured according to JASO 0607 “Automotive Tire Uniformity Test Method”. It was evaluated with the index value. The smaller this value, the smaller the LFV and RFV, and the better the uniformity.
[0035]
[Table 1]

It can be seen from Table 1 that the pneumatic tire using the carcass material obtained by the method of the present invention can improve both LFV and RFV, and can improve uniformity.
[0036]
【The invention's effect】
As described above, the present invention provides a width satisfying the above formula when manufacturing a carcass material for a pneumatic tire used for a carcass layer in which reinforcing cords are arranged at an angle smaller than 90 ° with respect to the tire circumferential direction. By using the strip material, it is possible to produce a variety of products in small quantities, reduce the stock space of the carcass material, and further improve the uniformity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a principal part of a tire meridian showing an embodiment of a pneumatic tire manufactured using a carcass material obtained by the method for manufacturing a carcass material for a pneumatic tire of the present invention.
FIG. 2 is an explanatory view showing a method for producing a carcass material for a pneumatic tire according to the present invention.
FIG. 3 is a front view of the carcass material obtained in FIG. 2;
FIG. 4 is a cross-sectional view of a strip material used for a carcass material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 15 Forming drum 16 Strip material 16a End surface 16b Winding start end 16c Winding end 17 Cylindrical carcass material 20 Carcass material F Drum axis L Length of carcass material W Circumference of molding drum Long Y Carcass material width f Reinforcement cord k Unvulcanized rubber x Strip material width α Winding angle α 'Desired winding angle

Claims (6)

A carcass material for a pneumatic tire used for a carcass layer in which reinforcing cords extending in the tire width direction at an angle smaller than 90 ° with respect to the tire circumferential direction are arranged in the rubber layer at predetermined intervals along the tire circumferential direction. A method of manufacturing comprising:
Strips adjacent to each other at a winding angle α smaller than 90 ° with respect to the drum circumferential direction on a forming drum having a circumferential length W corresponding to the width of the carcass material, with the reinforcing cord covered with unvulcanized rubber. When the cylindrical carcass material is formed by spirally winding a predetermined length corresponding to the length L of the carcass material while contacting the end surfaces of the materials, the following expressions (1) and (2) are satisfied. After the cylindrical carcass material is formed using a strip material having a width x to be formed, the cylindrical carcass material passes through the winding start end of the strip material and is cut along a line parallel to the drum axis. Manufacturing method of tire carcass material.
x = W · tan (90−α) (1)
L / x = integer (2) A desired winding angle α ′ is set in advance, the width x of the strip material is calculated by the equation (1) using the desired winding angle α ′ as the winding angle α, and the value of the width x is used to obtain the equation (2). When the obtained value is an integer, the value calculated by the equation (1) is the strip width x, the desired winding angle α ′ is the winding angle α,
When the value obtained by equation (2) is a decimal, the first decimal place is rounded down or rounded up to obtain an integer, and the value obtained from the integer using equation (2) as the width x of the strip material. The method for producing a carcass material for a pneumatic tire according to claim 1, wherein the winding angle α is calculated from the obtained value of the width x using the formula (1). The carcass for a pneumatic tire according to claim 2, wherein the first decimal point is rounded down or rounded up to an integer so that a difference between the calculated winding angle α and the desired winding angle α 'is within 1 °. A method of manufacturing the material. The method for producing a carcass material for a pneumatic tire according to claim 1, wherein the winding angle α is in a range of 70 ° to 88 °. The carcass for a pneumatic tire according to claim 1, 2, 3, or 4, wherein the carcass material has a width corresponding to a plurality of carcass layers, and a circumferential length W of the forming drum corresponds to a width of the carcass material. A method of manufacturing the material. The pneumatic tire manufactured using the carcass material manufactured by the manufacturing method of the carcass material for pneumatic tires of Claim 1, 2, 3 or 4.

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