JP4718215B2 - Pneumatic tire manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a pneumatic tire in which lines, characters, and the like of a color different from that of a main rubber are formed on a sidewall portion.

  Conventionally, for the purpose of improving fashionability, pneumatic tires in which characters such as lines of different colors from the main body rubber and manufacturer logos are formed on the sidewall portions are known. Such a pneumatic tire can be manufactured using, for example, a green tire as shown in FIG. In FIG. 8, a white rubber layer 8 having a color different from that of the main rubber is disposed on the sidewall portion 31 of the raw tire, and a thin cover rubber layer 9 having the same color as the main rubber is formed on the outer periphery of the white rubber layer. It is arranged. After this raw tire is vulcanized, a predetermined region of the cover rubber layer 9 is scraped off to expose the white rubber layer 8 so that lines, letters, etc. can be formed (see Patent Document 1 below). Further, there is known a method of vulcanizing using a mold having a predetermined inner surface shape so that a portion where the cover rubber layer 9 is scraped off does not become a groove shape, and protruding a predetermined region as shown in FIG. According to this method, by cutting off the protruding portion 32, a line, a character, or the like can be formed on a substantially flat surface (see Patent Document 2 below).

  On the other hand, as a method for forming a sidewall member constituting the sidewall portion, conventionally, a method by extrusion molding and a method by ribbon winding are known. The formed sidewall member is affixed together with other rubber members on the carcass ply wound around the drum. A raw tire can be formed by deforming the carcass ply along the tire shape and attaching a tread member.

  In the former method, it can be formed by extruding the rubber composition into a cross-sectional shape of the sidewall portion using an extruder and a molding die and cutting the rubber composition at a predetermined length. However, in this method, it is necessary to prepare a large number of sidewall members of each width dimension in order to correspond to each tire size. Further, in order to correspond to each size of a different color part such as a line, each width is required. It was necessary to prepare a sidewall member having a white rubber layer of a size. As a result, there is a problem that the number of parts of the sidewall member increases. In addition, every time the tire size is changed, it is necessary to change the position such as position adjustment, which decreases productivity. In addition, since a step or the like is generated at the joint portion of the rubber member, the uniformity of the tire is reduced.

In the latter method, a rubber ribbon (rubber strip) is spirally stacked in the tire circumferential direction and wound to form a sidewall member (see, for example, Patent Documents 3 to 5 below). Alternatively, a rubber ribbon is wound around the outer peripheral side of a molded product obtained by extrusion molding to form a sidewall member (see Patent Document 6 below). Subsequently, a rubber ribbon is wound around the outer periphery of the sidewall member to form a white rubber layer and a cover rubber layer, respectively. However, with this method, it is difficult to form the cover rubber layer thin with a constant thickness. As a result, when the cover rubber layer after vulcanization is scraped off with a buff or the like, there is a problem that the white rubber layer is not uniformly exposed and distortion occurs on the buff surface. This problem is remarkable when a predetermined region of the cover rubber layer 9 is projected as shown in FIG. In addition, since the rubber ribbon having a small cross-sectional dimension is wound many times, it takes time to form a tire and there is a problem that productivity is lowered.
JP-A-9-1694 JP 10-2222070 A JP 2002-79590 A JP 2002-200767 A International Publication No. 02/060676 Pamphlet Japanese Patent No. 3370282

  The present invention has been made in view of the above circumstances, and its purpose is a method for manufacturing a pneumatic tire in which lines and characters of a color different from that of the main body rubber are formed on the side wall, Another object of the present invention is to provide a method for manufacturing a pneumatic tire that can reduce the number of parts, is excellent in tire uniformity and productivity, and does not cause distortion on the surface on which lines, letters, and the like are formed.

The above object can be achieved by the present invention as described below. That is, the method for manufacturing a pneumatic tire according to the present invention is a method for manufacturing a pneumatic tire in which a portion having a color different from that of the main rubber is formed on the sidewall portion, and a different color rubber layer having a color different from that of the main rubber. Forming a band-shaped rubber member having a constant thickness on the surface of the different color rubber layer and a thin rubber layer having the same color as the main rubber, and forming the band-shaped rubber member on the outer periphery of a cylindrical molding drum. And a step of winding the ribbon in a spiral shape along the tire circumferential direction on both sides in the width direction of the position where the belt-shaped rubber member is disposed.

  According to the method for manufacturing a pneumatic tire of the present invention, a belt-like rubber member having a different color rubber layer different from the main rubber is formed, and rubber ribbons are wound around both sides in the width direction where the belt-like rubber member is disposed. Thus, a sidewall member can be formed. For this reason, by adjusting the winding of the rubber ribbon, the width dimension of the sidewall member and the position of the different color rubber layer can be changed. As a result, there is no need to prepare a sidewall member corresponding to each tire size, and the number of parts can be reduced. When changing the tire size, it is not necessary to change the position such as position adjustment, so that productivity can be improved. In addition, the configuration in which the rubber ribbon is wound can suppress generation of a step in the joint portion of the rubber member, and fine adjustment of the cross-sectional shape can be performed, so that excellent uniformity can be obtained. In addition, by using the belt-like rubber member, it is not necessary to wrap the rubber ribbon around the entire area, and the tire can be formed in a relatively short time. The thin rubber layer is formed with a constant thickness on the outer periphery of the different color rubber layer, and can form different color parts such as lines and characters without generating distortion on the surface of the side wall part. In the present invention, the main rubber refers to a rubber constituting most of the tire, excluding the different color rubber layer.

  In the above, it is preferable that the belt-like rubber member has a side rubber layer of the same color as that of the main rubber, which is disposed on both sides in the width direction of the different color rubber layer.

  With the above configuration, the rubber ribbon wrapping region can be reduced, so that the time required for tire molding can be effectively shortened and productivity can be improved.

  In the above, the step of forming the belt-like rubber member is obtained by rolling and forming the surface of the molded product obtained by the extrusion molding step and the extrusion molding step while joining the different color rubber layer and the side rubber layer. It is preferable that the thin rubber sheet is attached to form the thin rubber layer.

  According to the said structure, while being able to form a strip | belt-shaped rubber member easily, a thin rubber layer can be made thin and can be made into constant thickness with sufficient precision. Therefore, it is possible to expose the different color rubber layer without generating distortion on the surface and to suitably form lines, characters, and the like.

  In addition, it is preferable that both side surfaces of the belt-shaped rubber member have an inclined surface that extends downward, and an air vent groove is formed on the inclined surface. According to this configuration, since both side surfaces of the belt-like rubber member are inclined surfaces that expand downward, a gap is hardly formed when the rubber ribbon is wound, and the adhesion is also increased. At this time, since the air vent groove is formed on the inclined surface, defects due to air mixing can be effectively prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a raw tire. The raw tire T includes a bead portion 10 in which a bead 1a and a bead filler 1b, which are bead wire converging bodies, are disposed, a sidewall portion 30 extending from the pair of bead portions 10 outward in the tire radial direction, and a sidewall portion. And a tread portion 20 provided between 30. The carcass layer 7 is disposed between the pair of bead portions 10. An inner liner layer is disposed on the inner peripheral side of the carcass layer 7 in order to maintain air pressure, and a belt layer 6 that reinforces by the effect of the effect is disposed on the outer peripheral side of the carcass layer 7. The raw tire T is composed of a plurality of rubber members. In the example of FIG. 1, the raw tire T is composed of a tread member 2, a sidewall member 3, a rim strip member 4, and an inner liner member 5. The tire structure is the same as that of a general tire, and the present invention can be applied to any tire having the sidewall portion 30.

  The side wall member 3 has a white rubber layer 8 (corresponding to the different color rubber layer) of a color different from that of the main rubber on at least the outer side (right side in FIG. 1) when the vehicle is mounted. The white rubber layer 8 is continuously arranged with a constant width along the tire circumferential direction. A cover rubber layer 9 (corresponding to the thin rubber layer) having the same color as the main rubber is disposed on the outer periphery of the white rubber layer 8. The cover rubber layer 9 is thin and has a constant thickness. The other part of the sidewall member 3 is a black rubber layer 11 of the same color as the main rubber. After the tire T is vulcanized, a predetermined region of the cover rubber layer 9 is scraped off to expose the white rubber layer 8, whereby lines, letters, and the like can be formed on the sidewall portion 30.

  The raw tire T can be molded, for example, in the following manner. First, the inner liner member 5 is attached to the outer periphery of a cylindrical forming drum, and the carcass ply constituting the carcass layer 7 is attached to the outer periphery thereof. Next, the side wall member 3 and other rubber members are disposed at predetermined positions of the carcass ply, and an annular bead 1a is extrapolated in the vicinity of the end of the carcass ply, and the end is wound back through the bead 1a. Then, the central portion is inflated and deformed along the tire shape, and the tread member 2 is attached to the tread surface portion.

  Next, the sidewall member 3 will be described. FIG. 2 is a cross-sectional view of the sidewall member according to the present embodiment. The side wall member 3 shown in FIG. 2 includes a belt-like rubber member 12 and rubber ribbons 13 wound around both sides of the belt-like rubber member 12 in the width direction. Further, the belt-like rubber member 12 is provided with a white rubber layer 8, a side rubber layer 14 that is disposed on both sides of the white rubber layer 8 in the width direction and has the same color as the main rubber, and an outer periphery of the white rubber layer 8. The cover rubber layer 9 having a thickness and the cushion rubber layer 15 (adhesive rubber layer) disposed on the inner periphery of the white rubber layer 8 are formed. The cushion rubber layer 15 is provided to enhance the adhesiveness between the belt-like rubber member 12 and the carcass ply.

  The side rubber layer 14 and the rubber ribbon 13 are preferably made of the same rubber composition, thereby suppressing the occurrence of cracks. On the other hand, the cover rubber layer 9 is preferably made of a rubber composition having a so-called migration preventing effect that prevents migration of the oil and anti-aging agent of the white rubber layer 8. A well-known thing can be used for the rubber | gum composition for having the said transition prevention effect, and the mixing | blending for obtaining the rubber | gum composition. In the present invention, the side rubber layer 14, the cover rubber layer 9, and the rubber ribbon 13 may be made of the same rubber composition.

  In the present embodiment, a separation distance d (for example, 5 to 10 mm) is provided between the end of the cover rubber layer 9 and the end of the outer peripheral surface of the side rubber layer 14. Thus, in this invention, what the edge part of the cover rubber layer 9 and the outer peripheral surface edge part of the side rubber layer 14 located in the width direction outer side spaced apart is preferable. If the cover rubber layer 9 is disposed over the width direction of the outer peripheral surface of the belt-like rubber member 12 and its end is joined to the rubber ribbon 13, the cover rubber layer 9 is made of a rubber composition different from that of the rubber ribbon 13. In some cases, cracks may occur at the interface, which is not preferable.

  The belt-like rubber member 12 can be formed by, for example, the apparatus shown in FIG. The apparatus includes a molding die 21, a plurality of extruders 22 and 23 connected to the molding die 21, calendar rolls 24 and 25, and a guide roller 26. Each of the extruders 22 and 23 kneads and feeds the rubber composition to be the white rubber layer 8 and the rubber composition to be the side rubber layer 14 into the molding die 21. The molding die 21 is molded into a predetermined cross-sectional shape while bonding the side rubber layers 14 to both sides of the white rubber layer 8 in the width direction. On the other hand, in the calendar roll 24, the rubber composition which becomes the cover rubber layer 9 is rolled to form the rubber sheet 16. The rubber sheet 16 is thin and has a constant thickness, for example, a thickness of 0.2 to 1.6 mm. The rubber sheet 16 is guided by the guide roller 26 and attached to the outer periphery of the molded product 18 extruded from the molding die 21. Similarly, in the calender roll 25, the rubber composition to be the cushion rubber layer 15 is rolled and formed into a rubber sheet 17 having a certain thickness and is attached to the inner periphery of the molded product 18. Since the molded product 18 immediately after extrusion is in a hot state, the rubber sheets 16 and 17 are effectively attached.

  Here, the rubber composition is prepared by kneading a rubber material and its compounding material by a conventional method. The rubber material is not particularly limited, and general-purpose rubbers such as natural rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR) can be used. Moreover, well-known things can be used for the extruders 22, 23, the molding die 21, and the like.

  The formed belt-like rubber member 12 is arranged on the outer peripheral surface of a cylindrical molding drum or is attached to a carcass ply on the molding drum, and rubber ribbons 13 are wound around both sides in the width direction. Known devices are used for the winding device and the winding method of the rubber ribbon 13. For example, in a state where the winding start end of the rubber ribbon 13 is fixed to the end of the belt-like rubber member 12, the rubber drum 13 is moved in the tire circumferential direction by rotating the molding drum in a predetermined direction and moving the rubber ribbon 13 in the drum axial direction. It can be wound in a spiral. At that time, by appropriately adjusting the rotational speed of the forming drum or the moving speed of the rubber ribbon 13 in the drum axial direction, a desired width dimension and cross-sectional shape of the sidewall member 3 can be obtained, and the white rubber layer 8 can be placed at a predetermined position. Can be arranged.

  Here, as shown in FIG. 2, it is preferable that the end of the belt-like rubber member 12 (in the present embodiment, the end of the side rubber layer 14) is inclined and has a skirt. Thereby, it becomes easy to continue the rubber ribbon 13 and it is possible to suitably suppress the occurrence of a step in the joint portion. The rubber ribbon 13 shown in FIG. 2 is conceptually described, and is actually finer and has a complicated cross-sectional shape.

  The rubber ribbon 13 is made of an unvulcanized rubber composition having a relatively small width dimension and thickness dimension, and each dimension can be variously changed according to the tire size and the like. In addition, the cross-sectional shape of the rubber ribbon 13 is not particularly limited, and a preferable shape can be adopted according to the cross-sectional shape of the member, such as a horizontally long rectangle, a trapezoid, or a crescent shape. The rubber ribbon 13 may be continuously wound, but may be discontinuous. Furthermore, you may change the cross-sectional shape or dimension of the rubber ribbon 13 in the middle of winding. The rubber ribbon 13 may be supplied while being unwound from a fabric once wound up by extrusion, or may be supplied as it is after being extruded.

  Here, the width of the belt-like rubber member 12 is preferably 40 to 150 mm. If the width of the belt-like rubber member 12 is less than 40 mm, the winding region of the rubber ribbon 13 becomes large, and it takes time to form the tire. On the other hand, if it exceeds 150 mm, the effect of improving uniformity by winding the rubber ribbon 13 is small. In addition, the thing corresponding to display areas, such as a line formed in the sidewall part 30, and a character, is used for the strip | belt-shaped rubber member 12. FIG. That is, the side wall member 3 corresponding to each tire size can be formed only by preparing the belt-like rubber member 12 having the white rubber layer 8 (for example, 20 to 70 mm) of each width dimension. Reduce.

  After the molded raw tire T is vulcanized in the mold, a predetermined region of the cover rubber layer 9 is scraped off by a buff or the like. As a result, the white rubber layer 8 is exposed from the buff surface, and lines, characters, and the like are formed. In addition, the number of lines to be formed, the width, the interval, and the like are not particularly limited, and characters and patterns such as a manufacturer logo can be formed in addition to the lines. Further, the different color rubber layer is not limited to the white rubber layer 8, and may be any color different from that of the main rubber (generally black).

[Another embodiment]
(1) In the above-described embodiment, the example of the belt-like rubber member 12 in which the side rubber layers 14 are disposed on both sides in the width direction of the white rubber layer 8 is shown. However, in the present invention, as shown in FIG. The rubber layer 8 may be thin and embedded in the side rubber layer 14. Thereby, the adhesiveness of the sidewall member 3 and the carcass ply can be improved.

  In the above-described embodiment, the example in which the boundary between the white rubber layer 8 and the side rubber layer 14 is parallel to the thickness direction of the belt-like rubber member 12 is shown. However, in the present invention, as shown in FIG. Alternatively, the boundary may be inclined with respect to the thickness direction of the belt-like rubber member 12. Thereby, it is possible to ensure a large display area such as a line while improving the adhesiveness of the belt-like rubber member 12. The band-shaped rubber member 12 shown in FIGS. 4A and 4B can be formed, for example, by using a molding die 21 that can obtain each cross-sectional shape in the apparatus of FIG.

  (2) This invention is not specifically limited about the formation method of rubber members other than a side wall member. Moreover, although the example which provided the cushion rubber layer 15 in the strip | belt-shaped rubber member 12 was shown in above-mentioned embodiment, this invention is not limited to this.

  (3) In the above-described embodiment, after the belt-shaped rubber member is arranged on the molding drum, the rubber ribbon is wound around both sides in the width direction, and the belt-shaped rubber member is joined to both sides in the width direction. After the rubber ribbon is wound in advance, a belt-like rubber member may be attached and joined (see FIG. 5D).

  (4) In the above-described embodiment, after the belt-shaped rubber member is arranged on the cylindrical molding drum, the rubber ribbon is wound on both sides in the width direction, and thereafter, the molding (shaping) into the tire shape is performed. In the present invention, a rubber ribbon may be wound around the side wall after shaping. In this case, the rubber ribbon can be spirally overlapped in the tire circumferential direction and wound by moving the rubber ribbon in the tire radial direction while rotating the shaped article around the tire axis.

  (5) In the above-described embodiment, the example of the shape of both side surfaces of the belt-like rubber member 12 is shown in FIG. 2, but in the present invention, the shape of both side surfaces of the belt-like rubber member 12 is not particularly limited. For example, the shape shown to Fig.5 (a)-(d) may be sufficient.

  In the example shown in FIG. 5A, both side surfaces of the belt-like rubber member 12 form inclined surfaces that extend downward. Also in this example, the belt-like rubber member 12 is formed of a white rubber layer 8, a side rubber layer 14 that is disposed on both sides of the white rubber layer 8 in the width direction and exhibits the same color as the main rubber, and is disposed on the outer periphery of the white rubber layer 8. It consists of a cover rubber layer 9 having a certain thickness and a cushion rubber layer 15 (adhesive rubber layer) disposed on the inner periphery of the white rubber layer 8. The inclined surface is formed by using the end surface of the side rubber layer 14 as an inclined surface. The rubber ribbon 13 is spirally wound along the tire circumferential direction so as to cover the inclined surface.

  In the example shown in FIG. 5B, both side surfaces of the belt-like rubber member 12 form substantially vertical end surfaces, and the side rubber layer 14 has a rectangular cross section.

  In the example shown in FIG. 5C, one side surface of the belt-like rubber member 12 forms an inclined surface that extends downward, and the other side surface forms an inclined surface that expands upward. In this example, a rubber ribbon to be joined to the inclined surface that spreads upward is wound in advance, and a belt-like rubber member is pasted and joined thereto, and then the rubber ribbon on the other side is wound.

  In the example shown in FIG. 5 (d), both side surfaces of the belt-like rubber member 12 form inclined surfaces that expand upward. In this example, rubber ribbons on both sides are wound in advance, and a belt-like rubber member is attached to the ribbon to join them.

  (6) In the above-described embodiment, an example in which both side surfaces of the belt-like rubber member are formed as flat surfaces has been shown. However, in the present invention, for example, as shown in FIG. An air vent groove may be formed. The air vent groove can be formed by knurling or embossing. The direction and shape of the air bleeding groove may be any, but it is preferable to have a groove with an angle of 0 to 60 ° with respect to the width direction of the belt-like rubber member.

  In order to effectively perform air bleeding during the molding process, the distance between the air bleeding grooves is preferably 2 to 30 mm, the groove width is preferably 0.5 to 2.0 mm, and the groove depth is 0.5 to 2 mm. 0 mm is preferable.

  (7) In the above-described embodiment, an example in which the rubber ribbon is not wound around the lower surface of the belt-shaped rubber member is shown. However, in the present invention, as shown in FIG. A rubber ribbon 13 may be wound around the side in advance. Thereby, when the rubber ribbon 13 is wound around the inclined surface, it is possible to effectively prevent air from being mixed at both ends of the belt-like rubber member 12.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. For the evaluation of the following items, test tires having a tire size of 265 / 70R16 were used.

(1) Molding time When the test tire was manufactured, the time required for forming the sidewall member was measured, and an index evaluation was performed with the result of Comparative Example 1 being 100. The larger the index, the shorter the formation time and the better the productivity.

(2) Uniformity Based on the test method prescribed | regulated to JISD4233, RFV (radial force variation) was measured and the uniformity of the tire was evaluated. Specifically, the tire was pressed against the rotating drum so that a predetermined load was applied, and the amount of variation in the reaction force in the radial direction that occurred when the tire was rotated while keeping the distance between both axes constant was measured. The number of samples was 24. The index is evaluated with the result of Comparative Example 1 being 100, and the larger the index, the better the uniformity.

Comparative Example A side wall member formed by forming a test tire having a side wall portion integrally formed by extrusion molding as Comparative Example 1, and winding a rubber ribbon around the molding drum in a spiral shape. Thus, a test tire constituting the sidewall portion was set as Comparative Example 2.

Example A belt-shaped rubber member was formed by the method described above, and a rubber ribbon was wound around both sides in the width direction to form a sidewall member. The thickness of the belt-like rubber member was kept constant at 4 mm, and the above items were evaluated by changing the width of the belt-like rubber member.

表１に示すように、比較例１は、押出成形で得られたサイドウォール部材を貼り付けるだけでよいため、成形時間が最も短い。しかし、ゴム部材のジョイント部において段差等が発生するため、タイヤのユニフォミティが比較的低い。また、評価項目では挙げていないが、各タイヤサイズに対応したサイドウォール部材を多数用意しておく必要があるため、部品点数が多くなってしまうという問題もある。比較例２は、ゴムリボンを巻き付けてサイドウォール部材を形成するものであるため、ユニフォミティに優れているが、ゴムリボンを幾重にも巻き付ける必要があるため、成形時間が比較的長くなる。

As shown in Table 1, Comparative Example 1 has the shortest molding time because it is only necessary to attach the sidewall member obtained by extrusion molding. However, since a step or the like is generated at the joint portion of the rubber member, the tire uniformity is relatively low. In addition, although not listed in the evaluation items, there is a problem that the number of parts increases because it is necessary to prepare a large number of sidewall members corresponding to each tire size. Comparative Example 2 is excellent in uniformity because the side wall member is formed by winding the rubber ribbon, but the molding time is relatively long because the rubber ribbon needs to be wound several times.

  On the other hand, in Examples 1-5, it turns out that it exists in a suitable range, respectively in shaping | molding time and uniformity. Thereby, it is possible to reduce the number of parts while ensuring good productivity and uniformity. In Examples 2 to 4, it can be seen that the balance between molding time and uniformity is more preferable.

Sectional view showing an example of raw tire Cross-sectional view of sidewall member Schematic diagram of an apparatus for forming a belt-shaped rubber member Sectional drawing of the belt-shaped rubber member concerning another form Sectional drawing of the belt-shaped rubber member concerning another form The perspective view of the belt-shaped rubber member concerning another form Sectional drawing of the belt-shaped rubber member concerning another form Sectional view showing the sidewall of a conventional green tire Sectional drawing which shows the side wall part of the conventional vulcanized tire

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Bead 2 Tread member 3 Side wall member 7 Carcass layer 8 White rubber layer 9 Cover rubber layer 10 Bead part 11 Black rubber layer 12 Band-shaped rubber member 13 Rubber ribbon 14 Side rubber layer 15 Cushion rubber layer 16 Rubber sheet 17 Rubber sheet 18 Extrusion product 20 Tread part 21 Die for molding 22 Extruder 24 Calendar roll 25 Calendar roll 30 Side wall part

Claims (4)

A method of manufacturing a pneumatic tire in which a portion of a color different from that of the main body rubber is formed on the sidewall portion,
Forming a belt-like rubber member having a different color rubber layer different from the main rubber, and a thin rubber layer of the same color as the main rubber formed on the surface of the different color rubber layer with a constant thickness;
Arranging the belt-like rubber member on the outer periphery of a cylindrical molding drum;
And a step of winding the ribbon in a spiral shape along the tire circumferential direction on both sides in the width direction of the position where the belt-shaped rubber member is disposed.   2. The method for manufacturing a pneumatic tire according to claim 1, wherein the belt-shaped rubber member has side rubber layers of the same color as that of the main rubber, which are arranged on both sides of the different color rubber layer in the width direction. The step of forming the band-shaped rubber member includes
Extruding while bonding the different color rubber layer and the side rubber layer,
The method for producing a pneumatic tire according to claim 2, further comprising a step of attaching a thin rubber sheet obtained by rolling to the surface of a molded product obtained by the extrusion molding step to form the thin rubber layer.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein both side surfaces of the belt-shaped rubber member form an inclined surface extending downward, and an air vent groove is formed on the inclined surface.

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