JP4415469B2 - Tire manufacturing method and molding drum for manufacturing the tire - Google Patents

Description

【００３８】
上記のＲＲＯの比較波形及びＲＦＶの比較波形と、表１から明らかなように、この発明ドラムは、タイヤの均一性を表す指標となるＲＲＯ、ＲＦＶが改善され、均一性を向上できることがわかる。
【００３９】
【発明の効果】
この発明は、上記のように構成したので、インナーライナー層の外周側に配設されるカーカス層の部分的変動を抑制することができるため、チューブレスタイヤの均一性を改善することが出来る効果がある。
【図面の簡単な説明】
【図１】この発明の第１実施形態を示すタイヤ成形用ドラムの斜視図である。
【図２】この発明の第２実施形態を示すタイヤ成形用ドラムの斜視図である。
【図３】図２のタイヤ成形用ドラムにインナーライナー層とカーカス層を巻き付けた状態を示す断面図である。
【図４】この発明の第３実施形態を示すタイヤ成形用ドラムの斜視図である。
【図５】従来のタイヤ成形用ドラムにインナーライナー層とカーカス層を巻き付けた状態を示す断面図である。
【図６】（ａ）は図５のＸ−Ｘ断面図、（ｂ）は図５のＹ−Ｙ断面図である。
【図７】従来の成形ドラムを使用した場合と、本発明の成形ドラムを使用した場合のタイヤ１周におけるＲＲＯの波形を示した説明図である。
【図８】従来の成形ドラムを使用した場合と、本発明の成形ドラムを使用した場合のタイヤ１周におけるＲＦＶの波形を示した説明図である。
【符号の説明】
１，１’，１'' タイヤ成形用ドラム ２，２Ａ セグメント
２ａ ドラム幅方向端面 ２ｂ 外周面
３ 切り欠き部 ４ 切り欠き溝
１１ インナーライナー層 １１ａ 端部
１１Ｘ スプライス部 １２ カーカス層
１３ ビードコア ａ ドラム幅方向長さ
ｂ 深さ ｃ ドラム周方向長さ
ｄ ドラム周方向幅[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire manufacturing method and a molding drum for manufacturing the tire, and more specifically, a tire manufacturing method for improving uniformity of a tubeless tire and a molding drum for manufacturing the tire. It is about.
[0002]
[Prior art]
A conventional tire-forming drum is formed in a cylindrical shape from a plurality of segments divided in the drum circumferential direction. Each segment has the same curvature and drum width, and is attached to be freely expandable.
[0003]
In order to form a tubeless tire with such a tire molding drum, first, an inner liner layer that prevents air permeation is wound around the molding drum, and the ends are spliced together.
[0004]
Subsequently, after the carcass layer is wound around the outer peripheral side, the bead core is set. However, as shown in FIG. 5, the end 11a of the inner liner layer 11 is spliced onto the molding drum 10, so that The splice portion 11X protrudes to the outer peripheral side, and the carcass layer 12 bonded to the outer peripheral side also has a convex portion.
[0005]
[Problems to be solved by the invention]
Therefore, as shown in FIG. 6B, the carcass widths Wa and Wb after setting the bead core 13 are different between the splice part 11X and other parts, and the carcass width Wa of the splice part 11X is the inner liner layer. It becomes longer by an amount corresponding to the thickness of 11, and partially fluctuates.
[0006]
Also in the drum circumferential direction of the carcass layer 12, only the portion where the splice portion 11 </ b> X exists protrudes outward, causing partial fluctuation. Such partial variations have contributed to adverse effects on tire uniformity, and improvements have been demanded.
[0007]
An object of the present invention is to provide a tire manufacturing method capable of improving the uniformity of a tubeless tire and a molding drum for manufacturing the tire.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the tire manufacturing method according to the present invention is a tubeless structure in which the notch portion has a drum width direction length wound around a drum for forming a tire on both end surfaces of one segment in the drum width direction. When a tire is formed by winding a sheet-shaped inner liner that has been cut into a length on a tire molding drum, each of which has a notch portion set to correspond to the thickness of the inner liner layer of the tire, Wrapping so that the end joint portion of the liner is positioned at the notch, and forming the shape so that the thickness at the joint portion of the inner liner is absorbed by the notch and does not protrude outside It is.
[0009]
Further, in another tire manufacturing method of the present invention, a thickness of an inner liner layer of a tubeless tire wound around a drum for forming a tire is formed in a notch groove that traverses one outer peripheral surface of the segment along the drum width direction. When forming a tire by winding a sheet-shaped inner liner that has been cut into a tire-forming drum that has been set to correspond, the end joint portion of the inner liner is positioned in the notch groove. The gist is to absorb the thickness of the coiled portion at the joint portion of the inner liner with the cutout groove so as not to protrude outside.
[0010]
Furthermore, according to another tire manufacturing method of the present invention, notch portions are respectively formed on one end surface in the drum width direction of the segment, and a notch groove that crosses the outer peripheral surface of the segment along the drum width direction is formed. When forming a tire by winding a sheet-shaped inner liner that has been cut into a fixed length around the formed tire molding drum, the end joint portion of the inner liner is positioned at the notch and the notch groove. The gist is that the thickness of the winding and the inner liner is absorbed by the notch and the notch groove so as not to protrude to the outside.
[0011]
Further, in the molding drum for manufacturing the tire of the present invention, a notch portion is formed on each end surface of one segment in the drum width direction, and the length of the notch portion in the drum width direction is defined as the tire molding drum. set to correspond to the thickness of the wound inner liner layer of a tubeless tire is rotated, it is an Abstract that it has narrow rather up the segment width between the notch portion.
[0012]
Further, in the molding drum for producing another tire of the present invention, a notch groove that traverses along the drum width direction is formed on one outer peripheral surface of the segment, and the depth of the notch groove The gist is that the thickness is set to correspond to the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum .
[0013]
Further, in the molding drum for producing another tire of the present invention, a notch portion is formed on each end face in the drum width direction of the segment, and the segment width between the notch portions is narrowed, while the outer circumference The gist is that a notch groove is formed on the surface so as to cross between the notch portions along the drum width direction.
[0014]
Since the present invention is configured as described above and has cutout portions on both end surfaces in the drum width direction of one segment, one end portion of the splice portion of the inner liner layer wound around the tire molding drum is cut out. It can be arranged in the part. Therefore, it becomes possible to make the carcass width of the splice part after setting the bead core the same as the carcass width of the part other than the splice part, and it is possible to suppress partial fluctuations of the carcass width. The uniformity of the tubeless tire can be improved.
[0015]
Further, by providing a notch groove on the outer peripheral surface of one segment, it is possible to arrange one end portion of the splice portion of the inner liner layer wound around the tire molding drum in the notch groove. For this reason, the outer peripheral surface of the inner liner layer has no protrusion due to the splice portion, so that the carcass layer wound around the outer periphery does not partially change in the drum circumferential direction. Therefore, the uniformity of the tubeless tire can be improved.
[0016]
Furthermore, the uniformity of the tubeless tire can be further improved by providing both the above-described notch and notch groove in one segment.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0018]
FIG. 1 is a perspective view showing a first embodiment of a molding drum for manufacturing a tire according to the present invention, where 1 is a tire molding drum and 2 is each segment constituting the tire molding drum 1.
[0019]
The tire molding drum 1 is formed in a cylindrical shape composed of a plurality of segments 2 divided in the drum circumferential direction. An expansion / contraction mechanism (not shown) is incorporated in the molding drum 1 so that each segment 2 can be expanded / contracted in synchronization with the drum radial direction.
[0020]
One segment 2A of the segments 2 is provided with a notch 3 on each end surface 2a in the drum width direction. The notch 3 is formed so as to reach from the outer peripheral surface 2b to the inner peripheral surface 2c of the segment 2A, and has a substantially rectangular shape when viewed from the drum radial direction and the drum width direction.
[0021]
The bottom surface 3a of the notch 3 is formed in a plane parallel to the drum circumferential direction, and the segment width between the notches 3 is narrow. The drum width direction length a of the notch 3 from the drum width direction end surface 2a to the bottom surface 3a is a length corresponding to the thickness of the inner liner layer of the tubeless tire wound around the forming drum 1.
[0022]
In this way, by providing the notches 3 in the drum width direction both end surfaces 2a of one segment 2A, the end 11a of one inner liner layer 11 in the splice 11X shown in FIG. Therefore, the carcass width Wa after setting the bead core 13 can be made the same as the carcass width Wb of the portion other than the splice portion 11X. Therefore, since the partial fluctuation of the carcass width can be prevented, the uniformity of the tubeless tire can be improved.
[0023]
2 and 3 are a perspective view and a cross-sectional view of a tire molding drum according to a second embodiment of the present invention. The tire molding drum 1 'is a notch in the tire molding drum 1 described above. Instead of the portion 3, a cutout groove 4 is provided on the outer peripheral surface 2 b of the segment 2 </ b> A so as to cross the drum width direction.
[0024]
The notch groove 4 is formed in a substantially rectangular shape when viewed from the outside in the drum radial direction, and is formed so as to reach both end surfaces 2a in the drum width direction. The bottom surface 4a is a curved surface parallel to the drum circumferential direction. The depth b of the notch groove 4 is a length corresponding to the thickness of the inner liner layer of the tubeless tire wound around the molding drum 1 ′.
[0025]
Thus, by providing the notch groove 4 on the outer peripheral surface 2b of one segment 2A, the end portion 11a of one inner liner layer 11 in the splice portion 11X is accommodated in the notch groove 4 as shown in FIG. Therefore, partial fluctuations that have occurred in the tire circumferential direction of the carcass layer 12 can be avoided. Therefore, the uniformity of the tubeless tire can be improved.
[0026]
FIG. 4 shows a perspective view of a tire molding drum according to the third embodiment of the present invention. This tire molding drum 1 '' is a combination of the first embodiment and the second embodiment described above. The notch groove 4 is communicated between the notch grooves 3. By combining the notch groove 3 and the notch groove 4 in this manner, the uniformity of the tubeless tire can be further improved.
[0027]
In each embodiment of the present invention described above, when the length a in the drum width direction of the notch 3 is numerically shown, it can be set in a range of 1 to 2 mm, and is appropriately selected depending on the type of tire. If the length a in the drum width direction is less than 1 mm, it becomes smaller than the thickness of the inner liner layer, so that it is difficult to obtain the effect of improving tire uniformity in any tubeless tire.
[0028]
On the other hand, if it exceeds 2 mm, the thickness of the inner liner layer becomes larger, so the carcass width Wa is undesirably too short in any tire. The depth b of the notch groove 4 can also be set to 1 to 2 mm, similarly to the length a in the drum width direction.
[0029]
The length c of the notch 3 in the drum circumferential direction is preferably 10 to 30 mm. If the drum circumferential length c is smaller than 10 mm, the splice portion 11X of the inner liner layer 11 may not be accommodated in the cutout portion 3 depending on the type of tire. On the other hand, if it exceeds 30 mm, the carcass width is shortened in the portions other than the splice portion 11X, which is counterproductive. The drum circumferential width d of the notch groove 4 can be set to 10 to 30 mm, similarly to the drum circumferential length c.
[0030]
In the above embodiment, the case where only the inner liner layer 11 is provided inside the carcass layer has been described. However, the present invention may be an inner liner layer in which a chafer layer is attached as a reinforcing layer. In that case, the length a of the notch 3 in the drum width direction and the depth b of the notch groove 4 correspond to the total thickness obtained by adding the thickness of the chafer layer to the thickness of the inner liner layer. It becomes the length to do.
[0031]
The present invention can be preferably used particularly for forming a tubeless tire for a passenger car.
[0032]
〔Example〕
The tire size is shown in FIG. 1 in which one of the segments is provided with a notch, and the conventional tire shaping drum without the notch (conventional drum). Produced tubeless tires of 215 / 70R16.
[0033]
The notch in the drum of the present invention has a length in the drum width direction of 2 mm and a drum circumferential length of 20 mm.
[0034]
When both tires were subjected to evaluation tests of RRO (Radial Runnout: maximum value of radial runout) and RFV (Radial Force Variation: maximum value of radial force fluctuation) under the measurement conditions shown below, Table 1 The result shown in was obtained.
[0035]
FIG. 7 shows the waveform of RRO in one round of the tire when the conventional molding drum is used and when the molding drum of the present invention is used. In the present invention, the waveform of RRO in the inner liner splice portion is shown. It was found that the value of was about half that of the prior art.
[0036]
FIG. 8 shows the RFV waveform in one round of the tire when the conventional molding drum is used and when the molding drum of the present invention is used, and the drum 1 mm narrow on one side of the present invention is used. In the case of using a drum that is 2 mm narrow on one side, it was found that the magnitude of the conventional radial force fluctuation is about half in the inner liner splice.
[0037]
[Table 1]

[0038]
As is apparent from Table 1 and the RRO comparison waveform and the RFV comparison waveform, it can be seen that the inventive drum can improve RRO and RFV, which are indicators of tire uniformity, and can improve uniformity.
[0039]
【The invention's effect】
Since the present invention is configured as described above, it is possible to suppress partial fluctuations of the carcass layer disposed on the outer peripheral side of the inner liner layer, and therefore, it is possible to improve the uniformity of the tubeless tire. is there.
[Brief description of the drawings]
FIG. 1 is a perspective view of a tire-forming drum showing a first embodiment of the present invention.
FIG. 2 is a perspective view of a tire molding drum showing a second embodiment of the present invention.
3 is a cross-sectional view showing a state in which an inner liner layer and a carcass layer are wound around the tire molding drum of FIG. 2. FIG.
FIG. 4 is a perspective view of a tire molding drum showing a third embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a state in which an inner liner layer and a carcass layer are wound around a conventional tire molding drum.
6A is a cross-sectional view taken along line XX in FIG. 5, and FIG. 6B is a cross-sectional view taken along line YY in FIG.
FIG. 7 is an explanatory diagram showing a waveform of RRO in one circumference of a tire when a conventional molding drum is used and when the molding drum of the present invention is used.
FIG. 8 is an explanatory diagram showing RFV waveforms in one circumference of a tire when a conventional molding drum is used and when the molding drum of the present invention is used.
[Explanation of symbols]
1, 1 ', 1''Tire molding drum 2, 2A Segment 2a Drum width direction end surface 2b Outer peripheral surface 3 Notch portion 4 Notch groove 11 Inner liner layer 11a End portion 11X Splice portion 12 Carcass layer 13 Bead core a Drum width Direction length b Depth c Drum circumferential length d Drum circumferential width

Claims (7)

Cutouts set on one end of each segment in the width direction of the drum so that the length of the cutout in the widthwise direction of the notch corresponds to the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum When a tire is formed by winding a sheet-shaped inner liner that has been cut into a predetermined length on each of the tire molding drums, the end joint of the inner liner is wound so that it is positioned at the notch. A tire manufacturing method in which the thickness at the joint portion of the inner liner is absorbed by the cutout portion so as not to protrude to the outside. In the cylindrical tire molding drum consisting of a plurality of segments divided in the drum circumferential direction,
A notch is formed in each drum width direction end face of the segment, and the drum width direction length of the notch corresponds to the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum. set, a tire molding drum formed by narrow rather up the segment width between the notched section so as to. A tire molding drum in which a notch groove crossing along the drum width direction on one outer peripheral surface of the segment is set so as to correspond to the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum, When a tire is molded by winding a sheet-shaped inner liner that has been cut to a certain length, the inner liner terminal joint is wound so as to be positioned in the notch groove, A tire manufacturing method in which is molded so as to be absorbed by a notch groove and not to protrude outside. In the cylindrical tire molding drum consisting of a plurality of segments divided in the drum circumferential direction,
A notch groove that traverses along the drum width direction is formed on one outer peripheral surface of the segment, and the depth of the notch groove is the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum. Tire molding drum set to correspond to the thickness .   A notched portion is formed on each end face in the drum width direction of the segment, and a notched portion is cut into a tire forming drum in which a notch groove that traverses along the drum width direction is formed on one outer peripheral surface of the segment. When the tire is formed by winding a sheet-like inner liner, the inner liner terminal joint is wound so that it is located in the notch and the notch groove, and the thickness of the inner liner joint is reduced. A tire manufacturing method in which a rubber is absorbed by a notch and a notch groove so as not to protrude outside.   In a cylindrical tire-forming drum composed of a plurality of segments divided in the drum circumferential direction, notches are respectively formed on both end surfaces of one of the segments in the drum width direction, and the segment width between the notches is reduced. On the other hand, a tire-forming drum formed by forming a notch groove that crosses between the notch portions along the drum width direction on the outer peripheral surface.   The length of the notch in the drum width direction and the depth of the notch groove are set so as to correspond to the thickness of the inner liner layer of the tubeless tire wound around the tire molding drum. 9. A tire-forming drum according to 8.

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