JP2013039695A - Method of manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a tire having superior productivity and quality.SOLUTION: The method for manufacturing the tire includes: a step of obtaining unvulcanized first combinational member 26 by combining a plurality of members to compose the carcass, the belt, the bead, and the sidewall; a stitching step of stiching the tread member 12 to the first combinational member 26; and a vulcanization step in which a low cover obtained by the stitching step is vulcanized and formed. In this stitching step, this tread member 12 is located outside of radial of belt members 28 and 30. This tread member 12 includes grooves 18 and 20 in the outer peripheral surface. These grooves 18 and 20 extend to the tire circumferential direction. Ends 28a and 30a of the belt members 28 and 30 are located at the positions of the inner circumferential surface corresponding to the positions to which these grooves 18 and 20 extend, and this tread member 12 is stitched.

Description

  The present invention relates to a method for manufacturing a pneumatic tire.

  In the method for manufacturing a pneumatic tire, a plurality of members constituting a tread, a sidewall, an inner liner, and the like are combined to obtain an unvulcanized raw cover (green tire). The raw cover is placed in a mold and vulcanized at a predetermined temperature and pressure. A pneumatic tire is obtained through this vulcanization molding.

  6A and 6B show a part of the process of obtaining a raw cover by combining a plurality of members. The left-right direction in this figure is the tire axial direction, the up-down direction is the tire radial direction, and the direction perpendicular to the paper surface is the tire circumferential direction. FIG. 6A shows a first combination in which an inner liner member 2 constituting an inner liner, a carcass member 4 constituting a carcass, a sidewall member 6 constituting a sidewall, and a bead member 8 constituting a bead are combined. A member 10 and a tread member 12 placed on the first combination member 10 are shown.

  The stitching roller 14 presses the tread member 12 against the first combination member 10. The stitching roller 14 is pressed while moving from the axial center to the axial end. In FIG. 6B, one end portion of the tread member 12 is stitched to the first combination member 10. From one end of the tread member 12 to the other end is stitched to the first combination member 10, and the inner peripheral surface of the tread member 12 is joined to the outer peripheral surface of the first combination member 10. In this way, a raw cover is obtained. The obtained raw cover is put in a mold and vulcanized to obtain a tire.

JP 2010-89262 A

  In stitching with the first combination member in which the belt member is laminated on the outer peripheral surface, it takes time to sufficiently adhere the first combination member and the tread member. This stitching reduces tire productivity.

  An object of the present invention is to provide a method for manufacturing a tire excellent in productivity and quality.

The tire manufacturing method according to the present invention includes:
A step of combining a plurality of members for forming a carcass, a belt, a bead, and a sidewall to obtain an unvulcanized first combination member, and stitching for stitching an unvulcanized tread member to the first combination member A process and a vulcanization process in which the raw cover obtained in the stitching process is vulcanized.
In the stitching step, the tread member is located on the radially outer side of the belt member. The tread member has a groove on the outer peripheral surface. This groove extends in the tire circumferential direction. The end portion of the belt member is located at the position of the inner peripheral surface corresponding to the position where the groove extends, and the tread member is stitched.

  Preferably, in this manufacturing method, a groove is formed in an outer portion in the axial direction of the tread member. The end of the belt member is located on the curved surface of the first combination member that is bent in the radial direction from the axial direction. Preferably, the thickness T2 of the outer portion in the axial direction of the tread member is made thicker than the thickness T1 of the central portion.

  In the tire manufacturing method according to the present invention, stitching defects at the end of the belt member are suppressed. In this manufacturing method, the tread member can be efficiently stitched to the first combination member.

FIG. 1 is an explanatory view showing a part of a tread member used in a tire manufacturing method according to an embodiment of the present invention. FIG. 2 is an explanatory view showing a cross section of a part of the tread member of FIG. 1. FIG. 3 is a partially enlarged view indicated by an arrow II in FIG. FIG. 4 is an explanatory view showing a state where the tread member of FIG. 1 is stitched. FIG. 5 is an explanatory view showing a part of a tread member and a first combination member used in a tire manufacturing method according to another embodiment of the present invention. FIG. 6 is an explanatory view showing conventional stitching.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 shows a part of a tread member 16 used in the tire manufacturing method according to the present invention. The tread member 16 is made of unvulcanized rubber. The shape of the tread member 16 is a long band shape. The direction of arrow Y in FIG. 1 is the longitudinal direction of the tread member 16. The direction of arrow Z is the thickness direction of the tread member 16. An arrow X is the width direction of the tread member 16.

  The tread member 16 includes a central portion 16a located at the center in the width direction and a pair of end portions 16b located outside the center portion 16a in the width direction. The tread member 16 includes a groove 18 and a groove 20. The groove 18 and the groove 20 are located at the end 16b. The groove 18 and the groove 20 extend in the longitudinal direction of the tread member 16. The groove 18 and the groove 20 extend in parallel. The groove 20 is located outside the groove 18 in the width direction.

  A double-headed arrow T1 in FIG. 2 indicates the thickness of the central portion 16a of the tread member 16. A double-headed arrow T2 indicates the thickness of the end 16b of the tread member 16. This thickness T2 is the maximum thickness at the end 16b. The central portion 16a is formed with a constant thickness T1. The thickness of the end portion 16b gradually increases from the central portion 16a toward the outer side in the width direction and reaches the thickness T2. Thereafter, the thickness gradually decreases from the thickness T2 toward the outer side in the width direction.

  A point P1 in FIG. 2 indicates the deepest position of the groove 18 in the cross section. A one-dot chain line L1 is a straight line in the thickness direction passing through the point P1. A point P2 indicates the deepest position of the groove 20 in the cross section. A one-dot chain line L2 is a straight line in the thickness direction passing through the point P2. Point P3 is an intersection of the inner peripheral surface 22 of the top tread 16 and the straight line L1. This point P3 is the position of the inner peripheral surface 22 corresponding to the position where the groove 18 extends. Point P4 is an intersection of the inner peripheral surface 22 of the top tread 16 and the straight line L2. This point P4. This is the position of the inner peripheral surface 22 corresponding to the position where the groove 20 extends. In the portion of the inner peripheral surface 22 corresponding to the position where the groove 18 and the groove 20 extend, no groove or dent is formed. The portion of the inner peripheral surface 22 is made flat.

  A double-headed arrow D1 in FIG. 3 indicates the depth of the groove 18. A double-headed arrow D2 indicates the depth of the groove 20. The depths D1 and D2 are measured in the thickness direction. Depths D1 and D2 indicate the depths of the grooves 18 and 20 at the deepest positions. A double-headed arrow W1 indicates the width of the groove 18. The width W1 is measured as a linear distance from one ridge where the outer peripheral surface 24 of the top tread 16 and the wall surface of the groove 18 intersect to the other ridge. A double-headed arrow W2 indicates the width of the groove 20. The width W2 is measured as a linear distance from one ridge where the outer peripheral surface 24 of the top tread 16 and the wall surface of the groove 20 intersect to the other ridge. The depths D1 and D2 and the widths W1 and W2 are measured in the belt-like form of FIG. 1 before being placed on the first combination member 26.

  The tire manufacturing method includes a step of obtaining a first combination member 26 including an unvulcanized rubber member (STEP 1), and stitching an unvulcanized tread member 16 to the first combination member 26 to obtain a raw cover. A vulcanization step (STEP 2) and a vulcanization step (STEP 3) for obtaining a tire by vulcanizing and molding the raw cover with a mold at a predetermined temperature and pressure.

  In the step of obtaining the first combination member 26 (STEP 1), the first combination member 26 is obtained by combining a plurality of members. Examples of the plurality of members include an inner liner member for constituting an inner liner, a carcass member for constituting a carcass, a bead member for constituting a bead, and a sidewall member for constituting a sidewall. .

  A part of the first combination member 26 is shown in FIG. Similar to the first combination member 10 of FIG. 6, a radially outer peripheral surface is provided. The first combination member 26 includes a first belt member 28 and a second belt member 30 that constitute a first belt ply and a second belt ply. The first belt member 28 and the second belt member 30 as the belt members are located on the outermost side in the radial direction of the first combination member 26. Here, the first belt member 28 is laminated on the outer side in the radial direction of the second belt member 30.

  In this stitching step (STEP 2), the tread member 12 is disposed radially outside the first belt member 28 and the second belt member 30. Although not shown, the tread member is pressed against the first combination member 26 and stitched by the stitching roller. In this stitching step, the position of the point P3 on the inner peripheral surface 22 of the tread member 12 is located at the end portion 28a of the first belt member. A point P4 on the inner circumferential surface 22 of the tread member 12 is located at the end 30a of the second belt member. The tread member 12 is stitched to the first combination member 26 to obtain a raw cover.

  In this vulcanization step (STEP 3), the raw cover is placed in a mold and vulcanized at a predetermined temperature and pressure. By this vulcanization molding, the unvulcanized rubber member is changed to a crosslinked rubber. In this way, a tire is obtained.

  The end portion 28 a of the first belt member 28 is located at a portion of the inner peripheral surface 22 corresponding to the position of the groove 18 of the tread member 12. The tread member 12 is largely bent at the portion where the end portion 28a is located. Since the tread member 12 includes the groove 18, the tread member 12 is easily bent at a portion where the end portion 28a is located. The inner peripheral surface 22 of the tread member 12 is easily adhered to the outer peripheral surface of the first combination member 26. The adhesion failure of the first belt member 28a is suppressed. The stitching time of the first belt member 28a can be shortened.

  The groove 18 is formed on the outer peripheral surface 24. Even if the position of the end portion 28a is displaced with respect to the groove 18 in the width direction, the tread member 12 is easily bent at the position of the end portion 28a. It is difficult for a gap to be generated between the first combination member 26 and the tread member 16. Compared with the case where a groove is formed on the inner peripheral surface 22, poor adhesion is suppressed even if the position is shifted. This tire manufacturing method is excellent in productivity and quality.

  The raw cover obtained through the stitching process is placed in a mold and vulcanized at a predetermined temperature and pressure. The tread member 12 has a thickness T2 larger than the thickness T1 due to the mold shape. Since the groove 18 and the groove 20 are provided, the thick end portion 16b can be easily bent.

  From the viewpoint of facilitating bending of the tread member 16, the depth D1 of the groove 18 and the depth D2 of the groove 20 are preferably 0.5 mm or more, and more preferably 0.7 mm or more. On the other hand, the tread member 16 having shallow depths D1 and D2 is unlikely to be damaged after vulcanization. In this respect, 2.0 mm or less is preferable, 1.5 mm or less is more preferable, and 1.0 mm or less is particularly preferable.

  The tread member 16 in which the width W1 of the groove 18 and the width W2 of the groove 20 are large is easily bent. In this respect, 3 mm or more is preferable, 4 mm or more is more preferable, and 5 mm or more is particularly preferable. On the other hand, the tread member 16 having the small widths W1 and W2 is less likely to be damaged after vulcanization. In this respect, 9 mm or less is preferable, 8 mm or less is more preferable, and 7 mm or less is particularly preferable.

  Here, although the example provided with the 1st belt member 28 and the 2nd belt member 30 was demonstrated, the number of belt members may be one and may be three or more.

  FIG. 5 shows a tread member 31 and a first combination member 32 according to another embodiment. The first combination member 32 includes a belt member 34. A point P5 in FIG. 5 indicates the deepest position of the groove 36 of the tread member 31. Point P6 is the position of the inner peripheral surface 38 corresponding to the position of the groove 36. The end 34a of the belt member 34 is located on the curved surface of the first combination member 32 that is bent in the radial direction from the tire axial direction. The point P6 of the tread member 31 is positioned and stitched at the end 34a.

  Even if the end 34 a is located on the curved surface of the first combination member 32, the tread member 31 has the groove 36, so that the first combination member 32 easily adheres along the curved surface. Thus, even when the end portion 34a of the belt member 34 is located on the curved surface of the first combination member 32, the tire manufacturing method is excellent in productivity and quality.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
A raw cover obtained by stitching the tread member having the basic configuration shown in FIG. 1 was obtained. Two grooves are formed at the end of the tread member. The depth D1 of the groove on the inner side in the width direction was 1.0 mm, and the depth D2 of the groove on the outer side in the width direction was 0.7 mm. The width of each groove was 6 mm. The stitching time here was 9.6 seconds. The raw cover includes two belt members. The end portions in the axial direction of the belt member are respectively located on the inner peripheral surface corresponding to the position of the groove of the tread member. This raw cover was vulcanized to obtain a pneumatic tire of Example 1.

[Comparative Example 1]
A raw cover was obtained in the same manner as in Example 1 except that the tread member was not provided with grooves and the stitching time was 14.2 seconds. This raw cover was vulcanized to obtain a pneumatic tire.

[Examples 2 to 4]
Except that the depth D1 of the inner groove in the width direction and the depth D2 of the outer groove are as shown in Table 1 and the stitching time is as shown in Table 1, the same as in Example 1. I got a pneumatic tire. In Examples 3 and 4, the stitching time is longer than that in Example 1 from the viewpoint of preventing appearance scratches.

[Examples 5 to 7]
Pneumatic tires were obtained in the same manner as in Examples 2 to 4 except that the stitching times in Examples 2 to 4 were changed as shown in Table 2.

[quality evaluation]
The remaining air was evaluated for the obtained pneumatic tire. Specifically, the stitching portion was cut, and the remaining air at the belt end portion was visually inspected. The obtained pneumatic tire was inspected for scratches. Specifically, a visual inspection of the appearance was performed to check whether or not scratches such as irregularities remained at the position of the groove of the tread member. The results of the remaining air and the presence or absence of scratches are shown in Tables 1 and 2.

  As shown in Table 1 and Table 2, the manufacturing method of the example has higher evaluation than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present invention is clear.

2 ... Inner liner 4 ... Carcass 6 ... Side wall 8 ... Bead 10 ... First combination member 12, 31 ... Tread member 14 ... Stitching roller 16 ... Tread Member 18, 20 ... Groove 22 ... Inner peripheral surface 24 ... Outer peripheral surface 26 ... First combination member 28 ... First belt member 30 ... Second belt member 32 ... First One combination member 34 ... belt member 36 ... groove 38 ... inner peripheral surface

Claims (3)

Combining a plurality of members for constituting a carcass, a belt, a bead, and a sidewall to obtain a first combination member;
A stitching step of stitching the tread member to the first combination member;
And a vulcanization process in which the raw cover obtained in this stitching process is vulcanized,
In this stitching step, the tread member is located on the outer side in the radial direction of the belt member, the tread member has a groove on the outer peripheral surface, the groove extends in the tire circumferential direction, and the groove extends. A method for manufacturing a tire in which an end portion of a belt member is located at a position of an inner peripheral surface corresponding to the position, and the tread member is stitched. A groove is formed in the axially outer portion of the tread member,
The manufacturing method according to claim 1, wherein an end portion of the belt member is located on a curved surface of the first combination member that is bent in the radial direction from the axial direction.   The manufacturing method according to claim 1 or 2, wherein a thickness T2 of an axially outer portion of the tread member is thicker than a thickness T1 of a central portion.

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