JP4939853B2 - Holing equipment - Google Patents

Description

  The present invention relates to a holing device suitable for manufacturing a tire in which a plurality of sheet-like rubber members are laminated.

  The tire is obtained from a green tire. In this green tire, a large number of rubber members are laminated. Specific examples of the rubber member include an inner liner, a carcass ply, a sidewall rubber sheet, a belt ply, and a tread rubber sheet. The green tire is pressurized and heated in a mold. The rubber composition of a green tire flows by pressurization and heating. By heating, a crosslinking reaction occurs in the rubber composition. This process is called a vulcanization process.

  When green tires are molded, air may be caught in the green tires. This air exists between the rubber member and another rubber member. The air moves due to the flow of the rubber composition in the vulcanization process. By this movement, air can be discharged out of the green tire. However, if the movement is insufficient, air remains in the tire. In particular, air tends to remain in a tire in which the carcass ply includes a steel cord.

  Residual air hinders tire quality. For example, if air remains between the carcass ply and the sidewall, wrinkles are generated on the sidewall. Sidewalls with scissors are repaired. Repair takes time and effort. In addition, the residual air impairs the tire uniformity.

  Japanese Patent Application Laid-Open No. 2003-154579 discloses a holing device. This holing device includes a large number of cones. FIG. 7A shows the cone 2 and the carcass ply 4. As the cone 2 descends, the cone 2 penetrates the carcass ply 4 as shown in FIG. A hole 6 is formed in the carcass ply 4 by the penetration. The carcass ply 4 is laminated with another rubber member to obtain a green tire. In the vulcanization process, air is discharged from the holes 6.

JP 2003-154579 A

  As shown in FIG. 7B, at the stage where the cone 2 has penetrated the carcass ply 4, the carcass ply 4 has a warp 8 along with the hole 6. After the cone 2 is removed, as shown in FIG. 7C, the warp 8 may be restored and the hole 6 may disappear. When the cone 2 is pulled out, warping may occur upward, and the hole 6 may disappear due to restoration of the upward warping. In the carcass ply 4 that does not have the holes 6, it is difficult for air to be discharged.

  An object of the present invention is to provide a holing device capable of obtaining a high-quality tire.

  The holing device according to the present invention includes a cone having a streak groove and a land on the outer peripheral surface thereof, and a moving means capable of moving the cone forward and backward toward a rubber member for a tire.

The tire manufacturing method according to the present invention includes:
(1) a step of forming a hole in the sheet-like first rubber member by a cone having a streak groove and a land on its outer peripheral surface;
(2) A step in which a sheet-like second rubber member is laminated on the first rubber member to obtain a green tire, and (3) a step in which the green tire is pressurized and heated in a mold.

  When the first rubber member is a carcass ply, the thickness of the cone is 3.0 mm or more and 5.0 mm or less, the axial width of the streak is 4.0 mm or more and 6.0 mm or less, and the axial width of the land Is preferably 4.0 mm or more and 6.0 mm or less. The axial length of the tip of the cone is preferably 11.0 mm or more and 18.0 mm or less.

  When the first rubber member is a rubber sheet for a sidewall, the thickness of the cone is 2.0 mm or more and 8.0 mm or less, the axial width of the streak groove is 2.0 mm or more and 10.0 mm or less, The axial width is preferably 2.0 mm or more and 10.0 mm or less. The axial length of the tip of the cone is preferably 8.0 mm or greater and 20.0 mm or less.

  In the holing device according to the present invention, the muscle groove passes through the rubber member when the cone is advanced and retracted. The muscle groove suppresses warping. The hole device prevents the hole from disappearing. With this holing device, a tire with no remaining air can be obtained.

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

  FIG. 1 is a front view showing a holing device 10 according to an embodiment of the present invention together with a carcass ply 12. The holing device 10 includes an elevating unit 14, a driving unit 16, a table 18, and a conveyor 20. The carcass ply 12 is a sheet-like rubber member. The carcass ply 12 includes a large number of cords. The cord is made of steel or organic fiber. The carcass ply 12 is placed on the table 18 and the conveyor 20.

  The elevating unit 14 includes a piston 22, an elevating plate 24, a slider 26, a jaw 28, and a cone 30. The piston 22 extends in the vertical direction. The lower end of the piston 22 is connected to the upper surface of the lifting plate 24. The slider 26 has a rod shape. The slider 26 extends in the vertical direction. The lower end of the slider 26 is connected to the upper surface of the elevating plate 24. The jaws 28 are fixed to the bottom surface of the elevating plate 24. A large number of jaws 28 are arranged at predetermined intervals. The rear end of the cone 30 is inserted into the jaw 28. By tightening the jaw 28, the cone 30 is connected to the lifting plate 24. Although not shown, a large number of cones 30 are also arranged in the direction perpendicular to the paper surface.

  The drive unit 16 includes a cylinder 32, a base plate 34, and a guide 36. The cylinder 32 is fixed to the base plate 34. The guide 36 is fixed to the base plate 34. The guide 36 is cylindrical. A slider 26 is passed through the guide 36.

  The table 18 is located directly below the elevating unit 14. A number of holes 40 are formed in the top plate 38 of the table 18. The hole 40 is located immediately below the cone 30. The inner diameter of the hole 40 is slightly larger than the outer diameter of the cone 30.

  Two conveyors 20 are arranged with the table 18 in between. As the conveyor 20 rotates, the carcass ply 12 is conveyed in the direction of the arrow A1. Conveying means other than the conveyor 20 may be provided. An example of the other conveying means is a roller.

  As shown in FIG. 1, the piston 22 is inserted into the cylinder 32. As the piston 22 slides with respect to the cylinder 32, the elevating unit 14 moves up and down. When moving up and down, the slider 26 slides on the guide 36. By this rubbing, the elevating part 14 moves up and down while the elevating plate 24 is kept horizontal. By moving up and down, the cone 30 moves forward and backward toward the carcass ply 12. The cylinder 32 and the piston 22 constitute moving means. Other moving means may be provided. As another moving means, a motor is exemplified.

  FIG. 2 shows the holing device 10 in a state where the elevating unit 14 is lowered. By descending, the cone 30 penetrates the carcass ply 12. The cone 30 further passes through the hole 40 (see FIG. 1) of the top plate 38. After the elevating unit 14 is raised, the carcass ply 12 is conveyed by the conveyor 20. The carcass ply 12 includes a large number of holes (see FIG. 3).

  FIG. 3 is an enlarged view showing the cone 30 of the holing device 10 of FIG. 2 together with the carcass ply 12. In FIG. 3, the cone 30 penetrates the carcass ply 12. The cone 30 includes a main body 42 and a tip 44. The main body 42 has a spiral streak 46 on the outer peripheral surface thereof. A portion of the outer peripheral surface other than the streak groove 46 is a land 48. There is a step between the streak 46 and the land 48. The tip 44 is tapered. The groove 44 does not exist in the tip 44. A hole 50 is formed in the carcass ply 12 by the penetration of the cone 30.

  When the cone 30 moves forward and backward, the groove 46 and the land 48 alternately pass through the carcass ply 12. When the land 48 passes, the rubber composition of the carcass ply 12 is pulled to the land 48. The rubber composition is deformed and warps. After that, when the streak 46 passes, the warp is restored to some extent. Since deformation and restoration are repeated, a large warp is not generated. In this holing device 10, the sled does not block the hole 50 after the cone 30 is removed.

  FIG. 4 is a perspective view showing the carcass ply 12 in which the hole 50 is formed by the holing device 10 of FIG. In FIG. 4, what is indicated by an arrow A2 is the axial direction of the tire. The carcass ply 12 can be distinguished into both end portions 52 and a central portion 54. As is apparent from FIG. 4, the hole 50 is formed in the end portion 52. There is no hole 50 in the central portion 54. A hole 50 may be formed in the central portion 54.

  The carcass ply 12 is supplied to the former. Other sheet-like rubber members are also supplied to the former. Examples of the other rubber member include an inner liner, another carcass ply, a sidewall rubber sheet, a belt ply, and a tread rubber sheet. These rubber members are assembled in the former to obtain a green tire. At the time of assembly, another rubber member is laminated on the carcass ply 12.

  This green tire is subjected to a vulcanization process. In the vulcanization process, a green tire is put into a mold. The green tire is pressurized and heated with a mold and a bladder. The rubber composition flows by pressurization and heating. The rubber causes a crosslinking reaction by heating, and a tire is obtained. In the initial stage of the vulcanization process, air existing between the carcass ply 12 and the other rubber member is discharged from the green tire through the hole 50. Thereafter, the holes 50 are closed by the flow of the rubber composition.

  In the green tire using the carcass ply 12 shown in FIG. 4, the end portion 52 is located in the vicinity of the bead. Residual air near the bead extends along the cord and weakens the adhesion between the cord and the topping rubber. In particular, in a radial tire using a steel cord, insufficient adhesion tends to occur. By forming the hole 50 in the end portion 52, air remaining in the vicinity of the bead is suppressed. The width W1 of the end portion 52 is preferably 150 mm or greater and 250 mm or less, and more preferably 170 mm or greater and 230 mm or less. The number of holes 50 in one carcass ply 12 is preferably 200 or more and 500 or less. The pitch P between adjacent holes 50 is preferably 5 mm or greater and 300 mm or less.

  In FIG. 3, what is indicated by a double arrow φ is the thickness of the cone 30. Thickness φ is preferably 3.0 mm or greater and 5.0 mm or less. The disappearance of the holes 50 is suppressed by the cones 30 having a thickness φ of 3.0 mm or more. In this respect, the thickness φ is more preferably 3.5 mm or more. Damage to the carcass cord is suppressed by the cone 30 having a thickness φ of 5.0 mm or less. In this respect, the thickness φ is more preferably equal to or less than 4.5 mm. By this cone 30, a hole 50 having an inner diameter of 90% to 110% of the thickness φ can be formed.

  In FIG. 3, what is indicated by a double arrow WG is the axial width of the muscle groove 46. The width WG is preferably 4.0 mm or greater and 6.0 mm or less. The disappearance of the holes 50 is suppressed by the cones 30 having a width WG of 4.0 mm or more. From this viewpoint, the width WG is more preferably 4.5 mm or more. Cord damage is suppressed by the cone 30 having a width WG of 6.0 mm or less. From this viewpoint, the width WG is more preferably 5.5 mm or less.

  In FIG. 3, what is indicated by a double arrow WL is the axial width of the land 48. The width WL is preferably 4.0 mm or greater and 6.0 mm or less. The disappearance of the holes 50 is suppressed by the cones 30 having a width WL of 4.0 mm or more. In this respect, the width WL is more preferably 4.5 mm or more. Damage to the cord is suppressed by the cone 30 having a width WL of 6.0 mm or less. In this respect, the width WL is more preferably equal to or less than 5.5 mm.

  A double arrow D in FIG. 3 indicates the depth of the muscle groove 46. From the viewpoint of suppressing the disappearance of the holes 50, the ratio (D / φ) of the depth D to the thickness φ is preferably 0.10 or more, and more preferably 0.15 or more. In light of suppression of cord damage, the ratio (D / φ) is preferably equal to or less than 0.35, and more preferably equal to or less than 0.30.

  In FIG. 3, what is indicated by a double arrow L1 is the length of the tip 44. The length L1 is preferably 11.0 mm or greater and 18.0 mm or less. The cone 30 having a length L1 of 11.0 mm or more suppresses cord damage. In this respect, the length L1 is more preferably 13.0 mm or more. The disappearance of the holes 50 is suppressed by the cones 30 having the length L1 of 18.0 mm or less. In this respect, the length L1 is more preferably 16.0 mm or less.

  In FIG. 3, what is indicated by a double-headed arrow L2 is the protruding length of the cone 30 in a state in which the cone 30 is most advanced. The length L2 is preferably 60 mm or greater and 90 mm or less. By setting the length L2 to 60 mm or more, the disappearance of the holes 50 is suppressed. In this respect, the length L2 is more preferably equal to or greater than 65 mm. By setting the length L2 to 90 mm or less, damage to the cord is suppressed. In this respect, the length L2 is more preferably equal to or less than 85 mm.

  The hole 50 may be drilled in another rubber member by the holing device 10 shown in FIG. FIG. 5 shows a sidewall rubber sheet 56 having holes 50 formed therein. In FIG. 5, what is indicated by an arrow A3 is the circumferential direction of the tire. The rubber sheet 56 has an upper end 58 and a lower end 60. In the green tire, the upper end 58 is located near the tread, and the lower end 60 is located near the bead. In the rubber sheet 56, a clinch portion 64 is between the boundary line 62 and the lower end 60.

  The green tire using the rubber sheet 56 is subjected to a vulcanization process. In the initial stage of the vulcanization process, air existing between the rubber sheet 56 and the other rubber member is discharged from the green tire through the hole 50. Thereafter, the holes 50 are closed by the flow of the rubber composition. Since the hole 50 is closed, no bear is generated on the surface of the sidewall.

  As apparent from FIG. 5, the hole 50 is not present in the clinch portion 64. Since the holes 50 are not provided in the clinch portion 64 having a high hardness, generation of cracks starting from the holes 50 is prevented. The ratio of the width W3 of the region where the hole 50 is formed to the width W2 of the rubber sheet 56 is preferably 60% or more and 80% or less. The number of holes 50 in one rubber sheet 56 is preferably 150 or more and 800 or less. The pitch P between adjacent holes 50 is preferably 5 mm or greater and 300 mm or less.

  When the hole 50 is formed in the sidewall rubber sheet 56, the thickness φ of the cone 30 is preferably 2.0 mm or greater and 8.0 mm or less. The disappearance of the holes 50 is suppressed by the cones 30 having a thickness φ of 2.0 mm or more. In this respect, the thickness φ is more preferably 3.0 mm or more. If the thickness φ exceeds 8.0 mm, even if the rubber composition flows into the holes 50 in the vulcanization process, the holes 50 are not completely blocked. Due to the remaining holes 50, bears are generated on the surface of the sidewalls. In light of suppression of bears, the thickness φ is more preferably 7.0 mm or less.

  When the hole 50 is formed in the rubber sheet 56, the axial width WG of the muscle groove 46 is preferably 2.0 mm or greater and 10.0 mm or less. The cones 30 suppress the disappearance of the holes 50. From this viewpoint, the width WG is more preferably 3.0 mm or more. The width WG is more preferably 9.0 mm or less.

  When the hole 50 is bored in the rubber sheet 56, the axial width WL of the land 48 is preferably 2.0 mm or greater and 10.0 mm or less. The cones 30 suppress the disappearance of the holes 50. In this respect, the width WL is more preferably 3.0 mm or more. The width WL is more preferably 9.0 mm or less.

  When the hole 50 is formed in the rubber sheet 56, the ratio of the depth D to the thickness φ (D / φ) is preferably 0.10 or more from the viewpoint that the disappearance of the hole 50 is suppressed. .15 or more is more preferable. In light of suppression of bear, the ratio (D / φ) is preferably 0.35 or less, and more preferably 0.30 or less.

  When the hole 50 is formed in the rubber sheet 56, the length L1 of the tip 44 is preferably 8.0 mm or greater and 20.0 mm or less. Bears are suppressed by the cone 30 having a length L1 of 8.0 mm or more. In this respect, the length L1 is more preferably 10.0 mm or more. The disappearance of the holes 50 is suppressed by the cones 30 having a length L1 of 20.0 mm or less. In this respect, the length L1 is more preferably 18.0 mm or less.

  When the hole 50 is formed in the rubber sheet 56, the length L2 is preferably 60 mm or more and 90 mm or less. By setting the length L2 to 60 mm or more, the disappearance of the holes 50 is suppressed. In this respect, the length L2 is more preferably equal to or greater than 65 mm. By setting the length L2 to 90 mm or less, bear is suppressed. In this respect, the length L2 is more preferably equal to or less than 85 mm.

  FIG. 6 is a front view showing a part of the holing device 66 according to another embodiment of the present invention together with the carcass ply 12. In FIG. 6, the cone 68 of the holing device 66 is shown. The structure of the holing device 66 other than the cone 68 is the same as that of the holing device 10 shown in FIG.

  The cone 68 includes a main body 70 and a tip 72. The main body 70 has an annular stripe groove 74 on its outer peripheral surface. A portion of the outer peripheral surface other than the streak groove 74 is a land 76. There is a step between the streak groove 74 and the land 76. The tip 72 is tapered. The tip 72 has no streak 74. This cone 68 also suppresses warping of the carcass ply 12 and suppresses disappearance of the holes 50. The thickness φ, width WG, width WL, ratio (D / φ), length L1 and length L2 of this cone 68 are equivalent to those of the cone 30 shown in FIG.

  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.

[Experiment 1]
[Example 1]
A carcass ply with a steel cord was prepared. A number of holes were drilled in the carcass ply with the holing device shown in FIGS. The cone of this holing device has a thickness φ of 4 mm, a tip length L 1 of 15 mm, a stripe groove width WG of 5 mm, and a land width WL of 5 mm. The protruding length L2 at the time of drilling is 85 mm. The number of holes per carcass ply is 288. The pitch between adjacent holes is 25 mm. This carcass ply was supplied to the former. In this former, a green tire made of a carcass ply, an inner liner, a sidewall rubber sheet, a belt ply, a tread rubber sheet, and the like was molded. This green tire was pressurized and heated with a mold to obtain a radial tire for trucks. The size of this tire is “225 / 80R17.5”.

[Examples 4 to 7]
A radial tire was obtained in the same manner as in Example 1 except that the cone groove width WG and land width WL were as shown in Table 1 below.

[Examples 2 to 3 and 8 to 9]
A radial tire was obtained in the same manner as in Example 1 except that the cone having the tip length L1 shown in Table 1 below was used.

[Examples 12 to 14]
A radial tire was obtained in the same manner as in Example 1 except that a cone having a thickness φ shown in Table 2 below was used.

[Examples 11 and 15]
A radial tire was obtained in the same manner as in Example 1 except that a holing device having a protrusion distance L2 shown in Table 2 below was used.

[Examples 10 and 16]
A radial tire was obtained in the same manner as in Example 1 except that the number of holes was as shown in Table 2 below.

[Comparative Example 1]
A radial tire was obtained in the same manner as in Example 1 except that a cone having no streak was used.

[Comparative Example 2]
A radial tire was obtained in the same manner as in Example 1 except that no hole was formed.

[Calculation of residual rate of air]
2000 tires were visually observed, and the ratio of tires where residual air was observed was calculated. The results are shown in Tables 1 and 2 below.

[Cord damage]
The cord was visually observed and the degree of damage was rated according to the following criteria.
A: No damage B: Wrinkles are found in the filaments of the cord C: Cuts are found in the filaments of the cord The results are shown in Tables 1 and 2 below.

  As shown in Tables 1 and 2, the defect rate is small in the manufacturing method of the example.

[Experiment 2]
[Example 17]
Sidewall rubber sheets were prepared. A number of holes were drilled in this rubber sheet with the holing device shown in FIGS. The cone of this holing device has a thickness φ of 4 mm, a tip length L 1 of 15 mm, a stripe groove width WG of 5 mm, and a land width WL of 5 mm. The protrusion length L2 at the time of drilling was 85 mm. The number of holes per rubber sheet was 230. The pitch between adjacent holes was 30 mm. A rubber sheet was fed to the former. In this former, a green tire made of the rubber sheet, carcass ply, inner liner, belt ply, tread rubber sheet and the like was molded. This green tire was pressurized and heated with a mold to obtain a radial tire for trucks. The size of this tire is “225 / 80R17.5”.

[Examples 20 to 23]
A radial tire was obtained in the same manner as in Example 17 except that a cone having a width WG of the groove and a width WL of the land as shown in Table 3 below was used.

[Examples 18 to 19 and 24 to 25]
A radial tire was obtained in the same manner as in Example 17 except that the cone having the tip length L1 shown in Table 3 below was used.

[Examples 28 to 30]
A radial tire was obtained in the same manner as in Example 17 except that a cone having a thickness φ shown in Table 4 below was used.

[Examples 27 and 31]
A radial tire was obtained in the same manner as in Example 17 except that a holing device having a protrusion distance L2 shown in Table 4 below was used.

[Examples 26 and 32]
A radial tire was obtained in the same manner as in Example 17 except that the number of holes was as shown in Table 4 below.

[Comparative Example 3]
A radial tire was obtained in the same manner as in Example 17 except that a cone having no streak was used.

[Comparative Example 4]
A radial tire was obtained in the same manner as in Example 17 except that no hole was formed.

[Calculation of residual rate of air]
2000 tires were visually observed, and the ratio of tires where residual air was observed was calculated. The results are shown in Tables 3 and 4 below.

[Bear observation]
The tire sidewall was visually observed to determine the presence or absence of a bear. The results are shown in Tables 3 and 4 below.

  As shown in Tables 3 and 4, the defect rate is small in the manufacturing method of the example.

  Holes can be drilled in various rubber members by the holing device according to the present invention.

FIG. 1 is a front view showing a holing device according to an embodiment of the present invention together with a carcass ply. FIG. 2 is a front view showing the holing device of FIG. 1 together with the carcass ply. FIG. 3 is an enlarged view showing the cone of the holing device of FIG. 2 together with the carcass ply. FIG. 4 is a perspective view showing a carcass ply in which holes are formed by the holing device of FIG. 1. FIG. 5 is a perspective view showing a rubber sheet for a sidewall in which holes are formed by the holing device of FIG. FIG. 6 is a front view showing a part of a holing device according to another embodiment of the present invention together with a carcass ply. FIG. 7 is a front view showing a part of a conventional holing device together with a carcass ply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 66 ... Holing apparatus 12 ... Carcass ply 14 ... Elevating part 16 ... Drive part 18 ... Table 20 ... Conveyor 22 ... Piston 30, 68 ... Cone 32. ..Cylinder 42, 70 ... Main body 44, 72 ... Tip 46, 74 ... Muscle groove 48, 76 ... Land 50 ... Hole 56 ... Rubber sheet for sidewall

Claims (6)

A cone having a streak groove and a land on its outer peripheral surface, and a moving means capable of moving the cone forward and backward toward a rubber member not subjected to a crosslinking reaction for a tire ;
When the cone advances and retreats, the groove and land alternately pass through the rubber member, and when the land passes, the rubber member is pulled by the land and deformed to generate warp, A holing device in which a warp is restored when passing, and a hole is formed by repeating this deformation and restoration . A step of forming a hole in the first rubber member that is sheet-like and not cross-linked by a cone having a streak groove and a land on its outer peripheral surface;
A step of obtaining a green tire by laminating a sheet-like second rubber member on the first rubber member;
And a step of the green tire is pressurized and heated in the mold seen including,
When the cone advances and retreats, the groove and land alternately pass through the rubber member, and when the land passes, the rubber member is pulled by the land and deformed to generate warp, A method of manufacturing a tire in which a warp is restored when passing, and a hole is formed by repeating this deformation and restoration .   The first rubber member is a carcass ply, the cone thickness is 3.0 mm or more and 5.0 mm or less, the axial width of the streak is 4.0 mm or more and 6.0 mm or less, and the axial width of the land The manufacturing method according to claim 2, wherein is 4.0 mm or more and 6.0 mm or less.   The manufacturing method according to claim 3, wherein the tip is provided with a tip having a tapered shape, and the axial length of the tip is 11.0 mm or more and 18.0 mm or less.   The first rubber member is a sidewall rubber sheet, the cone thickness is 2.0 mm or more and 8.0 mm or less, the axial width of the streak groove is 2.0 mm or more and 10.0 mm or less, The manufacturing method according to claim 2, wherein the axial width is 2.0 mm or more and 10.0 mm or less.   The manufacturing method according to claim 5, wherein a tip having a tapered cone is provided, and an axial length of the tip is 8.0 mm or more and 20.0 mm or less.

Images