JP6575342B2 - Pneumatic tire manufacturing method and rubber strip - Google Patents

Description

  The present invention relates to a method for manufacturing a pneumatic tire including a step of forming a rubber member for a tire by spirally winding a belt-shaped rubber strip, and a rubber strip used in the manufacturing method.

  2. Description of the Related Art Conventionally, a method for manufacturing a pneumatic tire including a step of forming an annular rubber member for tires such as tread rubber and sidewall rubber by spirally winding an unvulcanized belt-like rubber strip has been proposed. However, such a manufacturing method has a problem that when air remains between the rolled rubber strips, the quality of the rubber member for tire after vulcanization is deteriorated.

  For example, in the method for manufacturing a pneumatic tire described in Patent Document 1 below, an inclined groove is provided on the outer surface of the rubber strip in order to discharge air between the rubber strips. However, even with the method for manufacturing a pneumatic tire disclosed in Patent Document 1, there is room for further improvement in the discharge of air from the rolled-up portion of the rubber strip.

JP 2006-051711 A

  The present invention has been devised in view of the above problems, and it is a main object of the present invention to provide a method for manufacturing a pneumatic tire and the like that can effectively discharge air between the rubber strips that are wound. It is said.

  The present invention is a method of manufacturing a pneumatic tire including a step of forming a rubber member for a tire by spirally winding a belt-shaped rubber strip, wherein the rubber strip includes a first outer surface and a first outer surface. A plurality of first inclined grooves in the longitudinal direction of the rubber strip, and the second outer surface has second inclined grooves in the longitudinal direction. When the rubber strip is seen through from the first outer surface, a plurality of the first inclined grooves and the second inclined grooves are inclined in directions opposite to each other.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the first inclined groove and the second inclined groove have an angle of 30 to 70 ° with respect to the longitudinal direction.

  In the method for manufacturing a pneumatic tire according to the present invention, it is desirable that when the rubber strip is seen through from the first outer surface, an intersection angle between the first inclined groove and the second inclined groove is 120 ° or less.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that each of the first inclined groove and the second inclined groove has a width of 0.5 to 2.0 mm.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that each of the first inclined groove and the second inclined groove has a depth of 0.10 to 0.45 times the thickness of the rubber strip.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the pitch P1 of the first inclined grooves and the pitch P2 of the second inclined grooves are 20 to 100 mm, respectively.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the pitch P1 of the first inclined groove is larger than the pitch P2 of the second inclined groove.

  According to a second aspect of the present invention, there is provided an unvulcanized rubber strip for forming a rubber member for a tire, which has a first outer surface and a second outer surface opposite to the first outer surface, The first outer surface is provided with a plurality of first inclined grooves in the longitudinal direction of the rubber strip, and the second outer surface is provided with a plurality of second inclined grooves in the longitudinal direction. When viewed through the first outer surface, the first inclined groove and the second inclined groove are inclined in directions opposite to each other.

  In the method for manufacturing a pneumatic tire of the present invention, a plurality of first inclined grooves are provided on the first outer surface of the rubber strip in the longitudinal direction of the rubber strip. A plurality of second inclined grooves are provided in the longitudinal direction on the second outer surface opposite to the first outer surface. When the rubber strip is seen through from the first outer surface, the first inclined groove and the second inclined groove are inclined in directions opposite to each other.

  When such a rubber strip is wound spirally, the first inclined groove provided on the first outer surface and the second inclined groove provided on the second outer surface intersect each other to generate a more complicated exhaust flow. A path is formed. Thus, during vulcanization molding, air between the rolled rubber strips is discharged to the outside through the first inclined groove or the second inclined groove, and an excellent quality tire member can be formed.

It is sectional drawing which shows one Embodiment of the pneumatic tire manufactured by the manufacturing method of this invention. It is sectional drawing of the tread rubber formed by the rubber strip winding up spirally. It is a front view of one embodiment of the rubber strip used for the manufacturing method of the pneumatic tire of the present invention. It is a perspective view of the rubber strip of FIG. (A) is the sectional view on the AA line of the 1st inclination groove | channel of FIG. 3, (b) is the BB sectional view of the 2nd inclination groove | channel of FIG. It is a side view of the groove forming apparatus used for a groove forming process.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a pneumatic tire (hereinafter, also simply referred to as “tire”) 1 manufactured by a method for manufacturing a pneumatic tire according to the present embodiment (hereinafter may be simply referred to as “production method”). It is sectional drawing which shows an example. As shown in FIG. 1, the tire 1 includes, for example, a carcass 6 that forms a skeleton of the tire and a plurality of types of tire rubber members 8 having different rubber blends. Each of these members has a known configuration.

  The tire rubber member 8 includes, for example, a tread rubber 9, a sidewall rubber 10, an inner liner rubber 11, a clinch rubber 12, and the like. The tread rubber 9 is disposed, for example, in the tread portion 2 and constitutes a ground plane. The sidewall rubber 10 is disposed, for example, on the sidewall portion 3 and constitutes the tire outer surface. The inner liner rubber 11 is disposed, for example, inside the carcass 6 and constitutes a tire lumen surface. The clinching rubber 12 is disposed, for example, in the bead portion 4 to prevent rim displacement. However, the tire rubber member 8 is not limited to these configurations.

  In the manufacturing method of the present embodiment, at least one of the above-described tire rubber members 8 is formed by spirally winding a belt-shaped rubber strip 15. FIG. 2 shows, as an example, a tread rubber 9 formed of a rubber strip 15 wound spirally. As shown in FIG. 2, in the manufacturing method of the present embodiment, an unvulcanized rubber strip 15 is applied to a wound body 14 having a cylindrical outer surface 13 along with the rotation of the wound body 14. The position is shifted to and spirally wound. Thereby, the rubber member 8 for tires (tread rubber 9 in FIG. 2) is formed. In addition, a well-known aspect is employ | adopted for the winding method of the rubber strip 15. FIG.

  FIG. 3 shows a front view of the rubber strip 15 of the present embodiment. As shown in FIG. 3, the width W of the rubber strip 15 is preferably 20 to 50 mm, for example. The thickness T (shown in FIG. 4) of the rubber strip 15 is preferably 0.5 to 5.0 mm, for example. However, the rubber strip 15 may be a belt shape and is not limited to the above-described specific mode.

  The rubber strip 15 has a first outer surface 16 and a second outer surface 17 on the opposite side. A plurality of first inclined grooves 21 are provided in the first outer surface 16 in the longitudinal direction of the rubber strip 15. The second outer surface 17 is provided with a plurality of second inclined grooves 22 (indicated by broken lines in FIG. 3) in the longitudinal direction.

  FIG. 4 shows an enlarged perspective view of the rubber strip 15. As shown in FIG. 4, when the rubber strip 15 is seen through the first outer surface 16, the first inclined groove 21 and the second inclined groove 22 are inclined in directions opposite to each other. When such a rubber strip 15 is spirally wound, the first inclined groove 21 provided on the first outer surface 16 and the second inclined groove 22 provided on the second outer surface 17 intersect each other. A more complicated exhaust flow path is formed. Thereby, at the time of vulcanization molding, the air between the rolled rubber strips 15 is discharged to the outside through the first inclined groove 21 or the second inclined groove 22 to form an excellent quality tire member. Can do.

  As shown in FIGS. 3 and 4, in the present embodiment, the first inclined groove 21 and the second inclined groove 22 are provided so as to intersect each other. As a more desirable mode, the first inclined groove 21 and the second inclined groove 22 intersect at the center position in the length direction. In such an embodiment, when the inclined groove is provided in the rubber strip base, the rubber strip base is strongly pressed against the grooved roller without being displaced, so that the productivity of the rubber strip is enhanced.

  The first inclined groove 21 and the second inclined groove 22 may be provided so as to be displaced in the length direction of the rubber strip 15 without crossing each other. Such an aspect serves to increase the durability of the rubber strip 15.

  As shown in FIG. 3, the first inclined groove 21 is inclined at an angle θ1 with respect to the longitudinal direction. The second inclined groove 22 is inclined at an angle θ2 with respect to the longitudinal direction. When the angles θ1 and θ2 are small, the inclined grooves 21 and 22 become excessively long and the rubber strip 15 may be easily cut. For this reason, the angles θ1 and θ2 are preferably 20 ° or more, more preferably 30 ° or more, and further preferably 40 ° or more. When the angle θ1 and the angle θ2 are large, the first inclined groove 21 and the second inclined groove 22 may not easily intersect when the rubber strip 15 is wound. Therefore, the angles θ1 and θ2 are preferably 80 ° or less, more preferably 70 ° or less, and further preferably 60 ° or less.

  As a more desirable aspect, in the present embodiment, the angle θ1 of the first inclined groove 21 is the same as the angle θ2 of the second inclined groove 22. When the angle θ1 is different from the angle θ2, the rubber strip 15 may be displaced in a specific manner when the rubber strip 15 is wound.

  The intersection angle θ3 between the first inclined groove 21 and the second inclined groove 22 is preferably 150 ° or less, more preferably 120 ° or less. Thereby, the above-described effect can be further enhanced. Note that the intersection angle θ3 is an angle that is convex in the length direction of the rubber strip 15, and corresponds to the sum of the angle θ1 of the first inclined groove 21 and the angle θ2 of the second inclined groove 22. .

  FIG. 5A shows a cross-sectional view taken along line AA of the first inclined groove 21 of FIG. FIG. 5B shows a cross-sectional view taken along the line BB of the second inclined groove 22 of FIG. As shown in FIGS. 5A and 5B, the first inclined groove 21 and the second inclined groove 22 have, for example, a semicircular cross-sectional shape. As a desirable mode, the first inclined groove 21 and the second inclined groove 22 have the same cross-sectional shape.

  The groove width W1 of the first inclined groove 21 and the groove width W2 of the second inclined groove 22 are each preferably 0.5 mm or more, more preferably 1.0 mm or more, preferably 2.0 mm or less, more preferably It is 1.5 mm or less. Such first inclined groove 21 and second inclined groove 22 can effectively exhaust air from the rolled-up portion of the rubber strip while maintaining the durability of the rubber strip 15.

  From the same viewpoint, the depth d1 of the first inclined groove 21 and the depth d2 of the second inclined groove 22 are each preferably 0.10 times or more, more preferably 0.20, the thickness T of the rubber strip 15. It is more than twice, preferably 0.45 times or less, more preferably 0.35 times or less.

  As shown in FIG. 3, the pitch P1 of the first inclined groove 21 and the pitch P2 of the second inclined groove 22 are each preferably 20 mm or more, more preferably 40 mm or more, preferably 100 mm or less, more preferably 80 mm or less. If the pitches P1 and P2 are smaller than 20 mm, the durability of the rubber strip 15 may be reduced. When the pitches P1 and P2 are larger than 100 mm, air may remain in the rolled-up portion of the rubber strip.

  When the pitch P1 of the first inclined groove 21 and the pitch P2 of the second inclined groove 22 are the same, stress concentrates on the inclined groove provided on the outer surface in the tire radial direction of the wound rubber strip 15, and the rubber The strip 15 may be easily cut. For this reason, for example, when the first outer surface 16 is arranged on the outer side in the tire radial direction and the rubber strip 15 is wound, the pitch P1 of the first inclined groove 21 provided on the first outer surface is the same as that of the second inclined groove 22. It is desirable to be larger than the pitch P2. Thereby, the cutting | disconnection of the rubber strip 15 which makes the starting point the 1st inclination groove | channel 21 distribute | arranged to the tire radial direction outer side can be suppressed.

  Next, a groove forming process in which inclined grooves are provided on each outer surface of the rubber strip 15 will be described. In addition, the manufacturing method of this embodiment suitably employs a known aspect except for the groove forming step. FIG. 6 shows a side view of the groove forming apparatus 25 used in the groove forming process. As shown in FIG. 6, the groove forming device 25 includes, for example, a first grooving roller 26 and a second grooving roller 27. In the present embodiment, the first grooving roller 26 and the second grooving roller 27 are provided at positions facing each other through a gap 28 through which the strip base 30 can pass. The first grooving roller 26 and the second grooving roller 27 are provided with ribs 29 a and 29 b for providing inclined grooves on the outer surface of the rubber strip 15, respectively. The rib 29a of the first grooving roller 26 and the rib 29b of the second grooving roller 27 are formed in the same direction with respect to the axial direction of the rollers 26, 27 in order to form the inclined grooves 21, 22 having different directions. Inclined and extended.

  The strip base 30 extruded from the extruder 32 passes between the first grooving roller 26 and the second grooving roller 27, and is formed on each outer surface 16, 17 by the ribs 29 a, 29 b of each roller 26, 27. Inclined grooves 21 and 22 are formed. Thereby, the rubber strip having the above-described inclined groove is obtained.

  As mentioned above, although the manufacturing method of the pneumatic tire of one embodiment of the present invention was explained in detail, the present invention is not limited to the above-mentioned specific embodiment, and is changed and carried out in various modes. The

  A rubber strip having the basic structure of FIG. 4 was molded according to the specifications in Table 1. One thousand pneumatic tires of size 215 / 45R17 were prototyped using each rubber strip. As Comparative Example 1, a rubber strip having no inclined groove on the outer surface was used, and a tire was molded in the same manner. As Comparative Example 2, a rubber strip provided with an inclined groove only on one outer surface was used, and a tire was similarly molded. As Comparative Example 3, a rubber strip provided with a first inclined groove and a second inclined groove inclined in the same direction when seen through from one outer surface was used, and a tire was molded in the same manner. For each of these manufacturing methods, the molding defect rate was measured. The specific test method is as follows.

<Molding defect rate>
The rate of occurrence of molding defects due to residual air in the rolled portion of the rubber strip or strip breakage was measured. A result is an index | exponent which sets the comparative example 1 to 100, and shows that it is so favorable that a molding defect rate is so small that a numerical value is small.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the manufacturing method of the example had a smaller molding defect rate than the manufacturing method of the comparative example.

8 Rubber member for tire 15 Rubber strip 16 First outer surface 17 Second outer surface 21 First inclined groove 22 Second inclined groove

Claims (8)

A method for manufacturing a pneumatic tire, including a step of forming a rubber member for a tire by spirally winding a belt-shaped rubber strip,
The rubber strip has a first outer surface and a second outer surface opposite to the first outer surface;
A plurality of first inclined grooves are provided on the first outer surface in the longitudinal direction of the rubber strip,
A plurality of second inclined grooves are provided in the longitudinal direction on the second outer surface,
A manufacturing method of a pneumatic tire, wherein the first inclined groove and the second inclined groove are inclined in opposite directions when the rubber strip is seen through from the first outer surface.   The method for manufacturing a pneumatic tire according to claim 1, wherein the first inclined groove and the second inclined groove have an angle of 30 to 70 degrees with respect to the longitudinal direction.   The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein when the rubber strip is seen through from the first outer surface, an intersection angle between the first inclined groove and the second inclined groove is 120 ° or less.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein each of the first inclined groove and the second inclined groove has a width of 0.5 to 2.0 mm.   The pneumatic tire according to any one of claims 1 to 4, wherein each of the first inclined groove and the second inclined groove has a depth of 0.10 to 0.45 times the thickness of the rubber strip. Production method.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 5, wherein a pitch P1 of the first inclined grooves and a pitch P2 of the second inclined grooves are 20 to 100 mm, respectively.   The method for manufacturing a pneumatic tire according to claim 6, wherein the pitch P1 of the first inclined grooves is larger than the pitch P2 of the second inclined grooves. An unvulcanized rubber strip for forming a rubber member for a tire,
A first outer surface and a second outer surface opposite to the first outer surface;
The first outer surface is provided with a plurality of first inclined grooves in the longitudinal direction of the rubber strip,
A plurality of second inclined grooves are provided in the longitudinal direction on the second outer surface,
When the rubber strip is seen through from the first outer surface, the first inclined groove and the second inclined groove are inclined in opposite directions to each other.

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