JP2008254339A - Method and apparatus for manufacturing tire and sound absorbing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for uniformly and precisely fixing a sound absorbing material in a tire peripheral direction under high productivity in attaching the sound absorbing material to the inner peripheral surface of the tire's tread part, and to stably provide a sound absorbing material-containing tire of high quality by applying the sound absorbing material to the tire. <P>SOLUTION: In attaching the strip of sound absorbing material at least to the inner peripheral surface of the tread part of the tire, as the sound absorbing material, one made stretchable at least in its longitudinal direction is used. This sound absorbing material is formed into such a size that its maximum diameter can pass through the rim hole of the tire to be inserted in the tire from the rim hole. Subsequently, the sound absorbing material is brought into contact with the inner peripheral surface of the tread part while stretched along the inner peripheral surface of the tread in the tire to be fixed to the inner peripheral surface of the tread through an adhesive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire manufacturing method, an apparatus for the same, and a sound absorbing material that reduce cavity resonance generated by vibration of filled air in a tire chamber.

  A pneumatic tire mounted on a vehicle has an internal shape or the like due to vibration of the tire tread portion caused by unevenness of the road surface and vibration of the filled air in the tire while the vehicle is running. The resulting cavity resonance results in noise called road noise in the car cabin.

  In order to avoid such road noise, Patent Document 1 discloses a tire formed by a rim and a pneumatic tire bonded to the rim in order to enhance the suppression effect of cavity resonance and greatly reduce road noise. A non-ring-shaped sound absorbing material using a sponge material is fixed to the inner cavity in the tire circumferential direction, and the sound absorbing material has a ratio S2 / S1 of the volume S2 to the total area S1 of the tire inner cavity of 0. 4% or more, and the sound absorbing material has a specific gravity of 0.005 to 0.06, and the surface of the sound absorbing material facing the tire cavity is an uneven surface, and the uneven surface is a protruding convex portion. There has been proposed an assembly of a pneumatic tire and a rim, in which recesses and recesses are scattered in the tire circumferential direction or the tire axial direction without being aligned and the irregularities are repeated.

  Further, Patent Documents 2 and 3 propose a tire having a sound absorbing material for reducing noise accompanying cavity resonance generated in the tire chamber.

  The tire with the sound absorbing material is usually provided with a sound absorbing material attached to the inner peripheral surface of the tread portion of the product tire. In the above-mentioned Patent Documents 2 and 3, the sound absorbing material having a shape that gives rigidity ( A method is disclosed in which a sponge or the like is manually inserted and then fixed by the restoring force of the sound absorbing material itself.

Patent Document 4 proposes a method in which a narrow-width member (sponge material) is attached in a spiral shape inside a rotating tire while applying an adhesive.
Japanese Patent No. 3622957 JP 2004-276809 A JP 2004-291855 A JP 2002-347418A

  When the sound absorbing material is attached to the inner peripheral surface of the tread portion of the tire, it is preferable to apply the integrally formed sound absorbing material along the inner peripheral surface of the tire at a time. However, in the examples of Patent Documents 2 and 3, when attaching a ring-shaped sound absorbing material having a large width so that sufficient characteristics can be obtained in one round on the inner peripheral surface of the tire, the diameter of the sound absorbing material is reduced, and then expanded. The work of diameter pasting is done manually. Therefore, this work takes time, so the productivity is low.Furthermore, it is difficult to arrange the sound-absorbing material uniformly and accurately in the tire circumferential direction and fix and adhere to it, and the quality is uneven. there were.

  In addition, in the example of Patent Document 4, a method of sticking a sound absorbing material having a narrow width in a spiral shape is proposed. However, in this method, the sound absorbing material is stretched more than necessary, and therefore, a sound absorbing material designed in advance is used. There arises a problem that the characteristics cannot be obtained and the film is easily peeled off. Further, when the sound absorbing material is spirally wound, a gap is generated between adjacent sound absorbing materials, and the sound absorbing effect may vary.

  Therefore, the object of the present invention is to solve the above-described problems, and to attach the sound absorbing material to the inner peripheral surface of the tread portion of the tire, the sound absorbing material is uniform and accurate in the tire circumferential direction, and under high productivity, The object is to stably provide a high-quality sound-absorbing material tire by providing a fixing method and apparatus, and further a sound-absorbing material.

The gist of the present invention is as follows.
(1) When attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
As the sound absorbing material, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
The sound absorbing material is inserted into the tire through the rim hole, with the maximum diameter being a size that can pass through the rim hole of the tire,
Next, in the tire, the sound absorbing material is brought into contact with the inner peripheral surface of the tread while extending the sound absorbing material along the inner peripheral surface of the tread, and the sound absorbing material is fixed to the inner peripheral surface of the tread with an adhesive. A method for manufacturing a tire, characterized in that
Note that, “the sound absorbing material has a size that allows the maximum diameter to pass through the rim hole of the tire” means that the maximum diameter of the sound absorbing material is the rim diameter as well as the maximum diameter of the sound absorbing material is equal to or less than the rim diameter. Even if it is above, when the sound absorbing material passes through the rim hole, for example, the sound absorbing material is compressed by contacting with the edge of the rim hole, and the maximum diameter of the sound absorbing material in a state of being in contact with the edge of the rim hole is This includes cases where the diameter is equal to or smaller than the diameter and passes through the rim hole.
In addition, “the sound absorbing material is brought into contact with the inner peripheral surface of the tread portion while the sound absorbing material is extended along the inner peripheral surface of the tread portion” is not limited to the case where the sound absorbing material is brought into contact with the inner peripheral surface of the tread portion. This includes the case of pressing against the inner peripheral surface.
Furthermore, the rim hole is a hole into which the wheel is inserted through the rim.

(2) In attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
As the sound absorbing material, at least according to the opening and closing of a plurality of slits provided at intervals in the longitudinal direction, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
The sound absorbing material is inserted into the tire through the rim hole, with the maximum diameter being a size that can pass through the rim hole of the tire,
Next, inside the tire, the sound absorbing material is opened along the inner peripheral surface of the tread portion while opening the slit of the sound absorbing material, and the sound absorbing material is extended along the inner peripheral surface of the tread portion, and the inner periphery of the tread portion is contacted with an adhesive. A tire manufacturing method, comprising fixing the sound absorbing material to a surface.

(3) In attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
As the sound absorbing material, at least according to the opening and closing of a plurality of slits provided at intervals in the longitudinal direction, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
A drum whose diameter can be expanded and contracted is reduced to be less than the rim diameter of the tire, and the sound absorbing material is wound around the drum,
The drum around which the sound absorbing material is wound is inserted into the tire from the rim hole of the tire,
Next, in the tire, the drum is expanded radially outward, the sound absorbing material is extended by opening the slit of the sound absorbing material, the sound absorbing material is brought into contact with the inner peripheral surface of the tread portion, and the adhesive is interposed through the adhesive. A method for manufacturing a tire, comprising fixing the sound absorbing material to an inner peripheral surface of a tread portion.

(4) A device for attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
The drum has a drum around which the sound absorbing material is wound, and the drum can be expanded and contracted between a diameter less than the rim diameter of the tire and a diameter larger than the diameter of the inner peripheral surface of the sound absorbing material attached to the inner peripheral surface of the tread portion of the tire. A tire manufacturing apparatus comprising:

(5) The tire manufacturing apparatus according to (4), further comprising an adhesive applicator for applying an adhesive to the inner peripheral surface of the tread portion.

(6) It is a band-shaped sound absorbing material attached to at least the inner peripheral surface of the tread portion of the tire, and can be expanded and contracted at least in the longitudinal direction according to opening and closing of a plurality of slits provided at intervals in the longitudinal direction. Characteristic sound absorbing material.

(7) In the above (6), the slits extend from both sides of the band in a direction crossing the longitudinal direction, and the slits on one side and the other side are alternately arranged in the longitudinal direction. Sound absorbing material.

(8) It has a side slit extending from both sides of the band in a direction crossing the longitudinal direction, and a central slit or a center punched portion arranged alternately in the side slit and the longitudinal direction at the center of the band. The sound-absorbing material as described in (6) above.

According to the present invention, when attaching the sound absorbing material to the inner peripheral surface of the tread portion of the tire, a method and apparatus for fixing the sound absorbing material in the tire circumferential direction uniformly and accurately and with high productivity and the sound absorbing material are provided. Therefore, a tire with a high quality sound absorbing material can be stably provided.
Moreover, in the tire manufacturing method of the present invention, since it is not necessary to stretch the material of the sound absorbing material itself, there is no problem that the sound absorbing material is easily peeled off after being applied to the inner peripheral surface of the tread portion of the tire.

  First, FIG. 1 shows a cross-sectional view in the width direction of a tire to which a sound absorbing material is attached using the method of the present invention. In addition, the structure of the tire to which the sound absorbing material is attached is not particularly limited, and may be a general structure. For example, in the illustrated tire 1, a bead core 3 is embedded in a bead portion 2, and a carcass 4 straddling between both bead portions 2 serves as a skeleton of the tire, and each side portion of the carcass 4 has a bead core 3. Wrapped around and fixed. On the radially outer side of the crown portion of the carcass 4, a belt 5 composed of three belt layers in which a large number of steel cords are covered with rubber is disposed in order from the inner layer side to the outer layer side. Both end portions of such a belt 5 are covered from the outer peripheral side by one or more layers 6 in the figure as a belt auxiliary layer. The tread portion 7 is disposed on the outer side in the radial direction of the belt 5, and there is a pair of sidewall portions 8 extending continuously inward in the radial direction on each side portion of the tread portion 7. E indicates the tire equatorial plane.

  In the tire 1, the sound absorbing material 30 is disposed at least on the inner peripheral surface of the tread portion 7. The end portions of the band-shaped sound absorbing material may be bonded to each other to form a ring shape, or may be used as a shape having a gap between the end portions.

  Here, the sound-absorbing material 30 can be composed of a synthetic resin such as an ether-based polyurethane foam or a foamed material having open cells or closed cells formed by foaming synthetic rubber, organic fibers, inorganic fibers, It can also be constituted by a woven fabric, a nonwoven fabric, a knitted fabric or the like in which animal fibers, plant fibers, synthetic fibers and the like are entangled and integrated.

Hereinafter, a method of attaching the sound absorbing material 30 to the inside of the tire 1 will be described in detail with reference to the drawings.
2 (a) to 2 (e) are diagrams for explaining the tire manufacturing method of the present invention.
First, as shown in FIG. 2A, a sound absorbing material 30 used in the present invention is prepared. The sound absorbing material 30 has a strip shape and a rectangular cross section. In the example shown in FIG. 2, the cross section of the sound absorbing material 30 is rectangular, but the cross section of the sound absorbing material is not particularly limited, such as other polygons such as a triangle or a pentagon, a circle, or a double mountain shape.
In addition, the sound absorbing material 30 has an outer diameter when it is made annular so that it can be inserted into the tire 1 from the rim hole after connecting the end portions in the longitudinal direction and making it annular in the following steps. The length needs to be able to pass through the hole.

Next, as shown in FIG. 2B, the sound absorbing material 30 is subjected to a plurality of slit processing. The strip-shaped sound absorbing material 30 having a rectangular cross section is provided with a plurality of slits 31 extending vertically from both side surfaces in the longitudinal direction. The slits 31 are introduced into the sound absorbing material 30 so as to be alternately arranged in the longitudinal direction on one side surface and the other side surface of the sound absorbing material 30. When the sound absorbing material 30 subjected to slit processing as described above is pulled in the longitudinal direction, the slit 31 is opened, and the sound absorbing material 30 is stretched in the longitudinal direction.
Here, the slit processing can be performed using a cutter, a slitter or the like.

  Next, as shown in FIG. 2 (c), the sound absorbing material 30 having the slits 31 is wound around the drum 10 by connecting the ends in the longitudinal direction into an annular shape. The drum 10 needs to have an outer diameter that allows the drum 10 to pass through the rim hole so that the drum 10 can be inserted into the tire 1 from the rim hole in the next step.

Next, as shown in FIG. 2D, the sound absorbing material 30 whose outer diameter is reduced to less than the rim diameter of the tire 1 in FIG. 2C is wound around the drum 10 from the rim hole 1RH while being wound around the drum 10. 1 Insert inside. Here, it is preferable that the tread portion inner peripheral surface 1IL of the tire 1 at the stage shown in FIG. 2 (d) is subjected in advance to a treatment such as application of an adhesive or application of an adhesive tape. The adhesive or the like may be applied to the entire tread portion inner peripheral surface 1IL of the tire 1 or may be applied partially. The application of the adhesive or the like may be performed using a spray or may be directly applied with a brush or the like.
Alternatively, an adhesive or the like may be applied in advance to the surface of the sound absorbing material 30 in FIG. 2A attached to the tread portion inner peripheral surface 1IL of the tire.

Next, the drum 10 is expanded radially outwardly, and the sound absorbing material 30 is expanded by opening the slit 31 of the sound absorbing material 30, and the outer diameter of the sound absorbing material 30 is reduced as shown in FIG. The diameter is the same as the inner periphery of the tread portion, the tire is brought into contact with the inner surface 1IL of the tread portion of the tire, and is fixed via an adhesive, an adhesive tape, or the like. The sound absorbing material 30 is expanded by opening the slit 31 and becomes a zigzag shape when attached to the tread portion inner peripheral surface 1IL of the tire.
Here, since the sound absorbing material 30 is expanded by opening the slit 31, the expansion and contraction of the material itself of the sound absorbing material 30 is suppressed to a minimum. By opening and closing the slit, a rigid material can be used as the sound absorbing material.
Further, as shown in FIG. 6 described later, it is possible to extend the sound absorbing material not only in the tire radial direction (circumferential direction) but also in the tire radial direction depending on how the slits are inserted.

  The tire 1 used here may be a raw tire before vulcanization molding or a product tire after vulcanization molding. However, when a raw tire is used, since the raw tire is vulcanized and molded after the sound absorbing material is attached, the sound absorbing material needs to be able to withstand pressure and heat during vulcanization molding.

  As described above, the application of the adhesive to the tire tread inner peripheral surface 1IL may be performed manually, but for example, the apparatus shown in FIG. 3 may be used. That is, FIG. 3 shows an example of an adhesive applicator for applying an adhesive to the inner peripheral surface 1IL of the tread portion of the tire. The adhesive applicator 40 is inserted into the tire through the rim hole of the tire, the jet outlet 40N thereof is directed to the inner peripheral surface 1IL of the tread portion, the adhesive 50 is jetted from the jet outlet 40N, and the jet outlet 40N is made of the tire. By rotating in the circumferential direction, the adhesive is applied over the entire circumference of the inner circumferential surface 1IL of the tread portion of the tire 1. In this example, the jet outlet 40N is rotated. However, the tire 1 may be rotated with the jet outlet 40N fixed.

The above-mentioned drum diameter expansion can be realized by a mechanism shown in FIG. 4, for example. That is, the drum 10 is composed of a plurality of segments as shown by the reference numerals 10a, 10b, 10c, 10d and 10e in FIG. Specifically, the expansion / contraction mechanism of the drum 10 will be described using the segments 10a, 10b, 10c, 10d and 10e shown in the drawing.
First, as shown in FIG. 4B, the segments outside the segments arranged in two rows at the time of diameter reduction are moved radially outward. That is, the segments 10b and 10d are moved outward in the radial direction of the drum. At this time, as the segments 10b and 10d move, the sound absorbing material (not shown) wound around the drum expands its diameter by opening the slit. However, the sound absorbing material at this time may not be a smooth ring depending on the material, but may be a polygon corresponding to the number of segments held from the inside of the ring.
Next, as shown in FIG. 4C, the segments 10a, 10c, and 10e also move outward in the radial direction of the drum. At this time, the sound-absorbing material (not shown) wound around the drum is held by the segments 10a, 10c, and 10e, and approaches a smoother ring.
In the description of FIG. 4, the segments are arranged in two rows at the time of diameter reduction, and the segments are moved outward in the radial direction of the drum over two stages to increase the diameter of the drum. Appropriate changes such as four rows are possible.
The width of the drum 10 to be used needs to be slightly narrower than the width of the tread portion so that the drum can be inserted into the tire and the diameter can be increased inside the tire.

5 (a) and 5 (b) show an embodiment of the sound absorbing material of the present invention.
The sound absorbing material 30 of FIG. 5A has a rectangular cross section, and the provided slits 31 are arranged on the opposite side surfaces of the sound absorbing material 30 at equal intervals in the longitudinal direction, with one surface perpendicular to the longitudinal direction. Has been.
FIG. 5B is a diagram in which the sound absorbing material 30 of FIG. 5A is pulled in the longitudinal direction and the slit 31 is opened to extend the sound absorbing material 30.

6 (a) to 6 (d) show another embodiment of the sound absorbing material of the present invention. The number, length, depth, and the like of the slits can be arbitrarily determined, and any of the examples shown below can be suitably used.
FIG. 6A is an example in which the slits 31 are not arranged at equal intervals.
FIG. 6B is an example in which one slit 31 is not formed on one surface but has a staircase shape, or an example in which the slit 31 is inclined rather than perpendicular to the longitudinal direction.
FIG. 6C shows an example in which one slit 31 is not formed by one surface but is formed by one surface of the cut opening and a surface derived from the surface. The illustrated sound absorbing material 30 can extend not only in the longitudinal direction but also in the width direction.
FIG. 6D shows an example in which the slit does not penetrate the two opposing surfaces of the sound absorbing material.
As shown in FIG. 6 (c), the slit may be provided in a direction transverse to the direction in which the sound absorbing material is extended, so that the sound absorbing material is extended not only in the longitudinal direction but also in the width direction, for example. For this purpose, it may be provided in a direction transverse to the width direction.

7 (a) to 7 (d) show another embodiment of the sound absorbing material of the present invention. FIG. 7B shows a state in which the sound absorbing material in FIG. 7A is extended in the longitudinal direction, and FIG. 7D shows a state in which the sound absorbing material in FIG. 7C is extended in the longitudinal direction.
The sound absorbing material in FIG. 7 (a) has a rectangular cross section. The sound absorbing material includes a side slit 31S extending in a direction crossing the longitudinal direction from opposite side surfaces of the sound absorbing material, and a central portion in the width direction of the sound absorbing material. The central slits 31C are arranged alternately in the longitudinal direction with respect to the side slits 31S. FIG. 7B is a diagram in which the sound absorbing material of FIG. 7A is pulled in the longitudinal direction and the sound absorbing material is expanded by opening the side slit 31S and the central slit 31C.
The sound absorbing material in FIG. 7 (c) has a rectangular cross section. The sound absorbing material includes a side slit 31S extending in a direction crossing the longitudinal direction from opposite side surfaces of the sound absorbing material, and a central portion in the width direction of the sound absorbing material. The punching portions 32 are arranged alternately in the longitudinal direction with respect to the side slits 31S. FIG. 7D is a diagram in which the sound absorbing material in FIG. 7C is pulled in the longitudinal direction and the sound absorbing material is expanded by opening the side slits 31 </ b> S and the punching portions 32. 7 (c) and 7 (d), the punched portion 32 has a hollow diamond shape, but may be round and the shape is not limited.
As shown in FIG. 7, by providing a slit on both sides of the band-shaped sound absorbing material and a slit or a punched portion in the central portion, the sound absorbing material can be reduced while suppressing the expansion of the sound absorbing material itself. It can be reliably fixed to the inner peripheral surface of the tread portion of the tire.

  In the above-described example, the sound absorbing material formed in a ring shape by connecting both ends in the longitudinal direction of the band-shaped sound absorbing material has been mainly described. However, the both ends of the band-shaped sound absorbing material are formed into an annular shape by locking them on the drum. You may affix a sound-absorbing material to the tread part inner peripheral surface of a tire. An endless ring-shaped sound absorbing material is more preferable from the viewpoint of tire uniformity. However, the ring-shaped sound absorbing material is difficult to be fixed by a conventional hand-pasting method as compared to the band shape. In addition, it is possible to attach a ring-shaped sound absorbing material.

The width direction sectional view of the tire which attached the sound-absorbing material using the method of the present invention is shown. (A)-(e) is a figure for demonstrating the manufacturing method of the tire of this invention. An example of the adhesive applicator for apply | coating an adhesive agent to the tread part inner peripheral surface of a tire is shown. (A)-(c) is a figure for demonstrating expansion / contraction of the drum which is an example of the manufacturing apparatus of the tire of this invention. (A), (b) shows an embodiment of the sound absorbing material of the present invention. (A)-(d) shows another embodiment of the sound absorbing material of the present invention. (A)-(d) shows another embodiment of the sound absorbing material of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 1IL Tread part internal peripheral surface 1RH Rim hole 2 Bead part 3 Bead core 4 Carcass 5 Belt 6 Layer 7 Tread part 8 Side wall part 10 Drum 10a, 10b, 10c, 10d, 10e Segment 30 Sound absorbing material 31 Slit 31S Side slit 31C Central slit 32 Punched part 40 Adhesive applicator 40N Spout 50 Adhesive E Tire equatorial plane

Claims (8)

In attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
As the sound absorbing material, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
The sound absorbing material is inserted into the tire through the rim hole, with the maximum diameter being a size that can pass through the rim hole of the tire,
Next, in the tire, the sound absorbing material is brought into contact with the inner peripheral surface of the tread while extending the sound absorbing material along the inner peripheral surface of the tread, and the sound absorbing material is fixed to the inner peripheral surface of the tread with an adhesive. A method for manufacturing a tire, characterized in that When attaching the band-shaped sound absorbing material to at least the inner surface of the tread portion of the tire,
As the sound absorbing material, at least according to the opening and closing of a plurality of slits provided at intervals in the longitudinal direction, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
The sound absorbing material is inserted into the tire through the rim hole, with the maximum diameter passing through the rim hole of the tire,
Next, inside the tire, the sound absorbing material is brought into contact with the inner peripheral surface of the tread portion while opening the slit of the sound absorbing material and extending the sound absorbing material along the inner peripheral surface of the tread portion. A tire manufacturing method, comprising fixing the sound absorbing material to a surface. In attaching the band-shaped sound absorbing material to at least the inner peripheral surface of the tread portion of the tire,
As the sound absorbing material, at least according to the opening and closing of a plurality of slits provided at intervals in the longitudinal direction, using a sound absorbing material that can expand and contract at least in the longitudinal direction,
A drum whose diameter can be expanded and contracted is reduced to be less than the rim diameter of the tire, and the sound absorbing material is wound around the drum,
The drum around which the sound absorbing material is wound is inserted into the tire from the rim hole of the tire,
Next, in the tire, the drum is expanded radially outward, the sound absorbing material is extended by opening the slit of the sound absorbing material, the sound absorbing material is brought into contact with the inner peripheral surface of the tread portion, and the adhesive is interposed through the adhesive. A method for manufacturing a tire, comprising fixing the sound absorbing material to an inner peripheral surface of a tread portion. A device for attaching a band-shaped sound absorbing material to at least an inner peripheral surface of a tread portion of a tire,
The drum has a drum around which the sound absorbing material is wound, and the drum can be expanded and contracted between a diameter less than the rim diameter of the tire and a diameter larger than the diameter of the inner peripheral surface of the sound absorbing material attached to the inner peripheral surface of the tread portion of the tire. A tire manufacturing apparatus comprising:   The tire manufacturing apparatus according to claim 4, further comprising an adhesive applicator for applying an adhesive to the inner peripheral surface of the tread portion.   A band-shaped sound absorbing material that is attached to at least an inner peripheral surface of a tread portion of a tire, and is capable of expanding and contracting at least in the longitudinal direction according to opening and closing of a plurality of slits provided at intervals in the longitudinal direction. Sound absorbing material.   The sound absorbing material according to claim 6, wherein the slits extend from both sides of the belt in a direction crossing the longitudinal direction, and the slits on one side and the other side are alternately arranged in the longitudinal direction.   The sound absorbing material according to claim 6, further comprising a side slit extending in a direction crossing the longitudinal direction from both sides of the band, and a center slit or a center punched portion at the center of the band.

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