JP2012040780A - Method of manufacturing pneumatic tire, and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a pneumatic tire excelling in moldability, and a pneumatic tire.SOLUTION: The method of manufacturing a pneumatic tire includes processes of: wrapping, around an outer peripheral surface of a cylindrical molding drum 21, a composite sheet 16 formed by combining an inner liner 13 formed of sheet-like and air nonpermeable rubber with chafers 14 each having a fibrous material, and a sheet-like carcass ply 6P; and externally fitting at least a pair of bead cores 5 into the outer peripheral surface of the carcass ply 6P to be shaped into a toroidal form. The composite sheet 16 is composed of: a sheet-like first inner liner 13A; a pair of chafers 14 respectively arranged at a distance L3 of 5.0-20.0 mm from both axial side edges of the first inner liner 13A; and a sheet-like second inner liner 13B arranged in the outside in the tire radial direction of the first inner liner 13A and the chafers 14 and stuck by straddling the chafers 14 on both the sides.

Description

  The present invention relates to a method for manufacturing a pneumatic tire excellent in moldability, and a pneumatic tire.

  In a general pneumatic tire manufacturing method, a composite sheet in which an inner liner made of a sheet-like and air-impermeable rubber and a chafer having a fiber material are combined on the outer peripheral surface of a cylindrical molding drum, and a sheet-like And a step of extrapolating at least a pair of bead cores on the outer peripheral surface of the carcass ply and shaping the toroidal shape.

  Further, as shown in FIG. 6A, the conventional composite sheet a is joined to both side edges be of the inner liner b in the axial direction by abutting the side edges ce of the chafer c. Related documents include the following (see Patent Document 1 below).

Japanese Patent Laid-Open No. 2005-199916

  However, in the composite sheet a, as shown in FIG. 6B, the inner liner b and the chafer c may overlap and be joined due to variations in manufacturing. In such a case, since a step is generated in the overlapping portion f, when the composite sheet a is rolled up and stocked, or when the carcass ply is attached and shaped, wrinkles or the like occur in the inner liner, There was a problem that moldability deteriorated.

  The present invention has been devised in view of the above circumstances, and a pair of outer peripheral surfaces of the molding drum is separated from both side edges in the axial direction of the sheet-like first inner liner by a predetermined distance. The main object is to provide a pneumatic tire manufacturing method and a pneumatic tire excellent in formability, based on the arrangement of the chafer.

  The invention according to claim 1 of the present invention is a composite sheet in which an inner liner made of a sheet-like and air-impermeable rubber and a chafer having a fiber material are combined on the outer peripheral surface of a cylindrical molding drum, and a sheet A pneumatic tire manufacturing method comprising: a step of winding a carcass ply, and a step of extrapolating at least a pair of bead cores to an outer peripheral surface of the carcass ply and shaping the bead core into a toroid shape, wherein the composite sheet is a sheet First inner liner, a pair of chafers spaced from each side edge in the axial direction of the first inner liner by a distance of 5.0 to 20.0 mm, and tires of the first inner liner and chafer It consists of the sheet-like 2nd inner liner which was distribute | arranged to the radial direction outer side, and was affixed across the said chafers of both sides And wherein the door.

  The invention according to claim 2 is the method for producing a pneumatic tire according to claim 1, wherein the distance is 7.0 to 13.0 mm.

The invention according to claim 3 includes a carcass having a carcass ply extending from the tread portion to the bead core of the bead portion through the sidewall portion,
An inner liner made of air-impermeable rubber disposed inside the carcass and extending in a toroidal manner between the bead portions of the tire cavity surface;
A pneumatic tire including a chafer having a fiber material including an upright portion extending from a bead toe and extending from the bead toe to the tire inner surface in a radial direction of the tire.
The inner liner includes a first inner liner on the tire lumen surface side and a second inner liner stacked on the outer side thereof, and an inner end of the first inner liner in the tire radial direction is an upright portion of the chafer. The outer end of the tire in the radial direction of the tire in the radial direction of the tire, and spaced apart from the outer end of the raised portion by 2.0 to 23.0 mm along the tire lumen surface, and the second inner The liner is a pneumatic tire characterized in that it extends at least to the bead core through the tire axially outer side of the upper portion of the chafer.

  The invention according to claim 4 is the pneumatic tire according to claim 3, wherein the second inner liner is folded around a bead core.

  The invention according to claim 5 is the pneumatic tire according to claim 3 or 4, wherein the chafer is a canvas chafer in which a canvas made of organic fibers is topped with rubber.

  In the present specification, unless otherwise specified, the size of each part of the tire is a value specified in a normal state with no load loaded with a normal rim and filled with a normal internal pressure.

  The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA and “Design Rim” for TRA. "If ETRTO," Measuring Rim ".

  Furthermore, “regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. “JAMATA” is the “highest air pressure”, TRA is the table “TIRE LOAD” Maximum value described in “LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” for ETRTO.

  In the method for producing a pneumatic tire of the present invention, a composite sheet in which an inner liner made of a sheet-like and air-impermeable rubber and a chafer having a fiber material are combined on the outer peripheral surface of a cylindrical molding drum, and a sheet-like shape A step of winding the carcass ply, and a step of extrapolating at least a pair of bead cores on the outer peripheral surface of the carcass ply and shaping the bead core into a toroid shape. The composite sheet includes a sheet-like first inner liner, a pair of chafers disposed at a distance of 5.0 to 20.0 mm from each side edge in the axial direction of the first inner liner, The inner liner and the chafer are arranged on the outer side of the tire in the radial direction of the tire, and are formed of a sheet-like second inner liner pasted on both sides of the chafer.

  In such a manufacturing method, since the first inner liner and the chafer are attached to the molding drum in a state of being reliably separated without overlapping in the tire radial direction, a step is generated due to the overlap between the chafer and the first inner liner. Can be suppressed. Accordingly, when the carcass ply is attached and shaped into a toroid shape, wrinkles and the like can be prevented from being generated on the inner liner, and the moldability of the tire can be improved.

  In addition, since the separation distance between the first inner liner and the chafer is limited to the above range, molding defects due to insufficient rubber flow during vulcanization molding can be suppressed, and the second inner liner is pasted over the two. Therefore, the internal pressure retention of the tire is not deteriorated.

It is sectional drawing which shows the pneumatic tire of this embodiment. It is the elements on larger scale of the bead part of FIG. (A), (b) is sectional drawing explaining the process of winding a composite sheet and a carcass ply. It is sectional drawing explaining a shaping process. (A) is a side view which shows a roll body and a composite sheet, (b) is the elements on larger scale of (a). (A) is a perspective view which shows the conventional composite sheet, (b) is a perspective view which shows the composite sheet which has a level | step difference.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows, for example, a tire for SUV (Sports Utility Viechle) as a pneumatic tire (hereinafter, simply referred to as “tire”) formed by the manufacturing method of the present invention. The tire 1 includes a carcass 6 that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and a tread reinforcing layer 7 that is disposed inward of the tread portion 2 and radially outward of the carcass 6. Is provided.

  The carcass 6 has one or more radial structures in which carcass cords are arranged at an angle of, for example, 80 to 90 degrees with respect to the tire equator C, and in this embodiment, two carcass plies 6P (first carcass ply 6A and second carcass ply 6A). Carcass ply 6B). As the carcass cord, for example, an organic fiber cord such as polyester, nylon, rayon, aramid, or a steel cord is used if necessary.

  The first and second carcass plies 6A and 6B include main body portions 6a1 and 6b1 extending from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, and the bead cores extending from the main body portions 6a1 and 6b1. 5 are folded back portions 6a2 and 6b2 that are folded back from the inner side to the outer side in the tire axial direction, and the outer ends of the turned back portions 6a2 and 6b2 are provided so as to be displaced from each other in the tire radial direction. Between the main body portions 6a1 and 6b1 and the folded portions 6a2 and 6b2 of the first and second carcass plies 6A and 6B, a bead apex 8 made of hard rubber extends from the bead core 5 outward in the tire radial direction. The bead part 4 is appropriately reinforced.

  The bead apex 8 is made of, for example, a hard rubber having a rubber hardness of 65 to 98 degrees, and increases the bending rigidity of the bead portion 4 to suppress the longitudinal deflection of the tire 1. In addition, in this specification, rubber hardness shall be the hardness by durometer type A in a 23 degreeC environment based on JIS-K6253.

  The tread reinforcing layer 7 includes a belt layer 9 disposed on the outer side of the carcass 6 in the tire radial direction and a band layer 10 disposed on the outer side of the belt layer 9 in the tire radial direction.

  The belt layer 9 has two belt plies 9A and 9B arranged with the belt cord inclined with respect to the tire equator C at, for example, about 10 to 35 degrees so that the belt cords intersect each other. . As the belt cord, a steel cord, or a highly elastic organic fiber cord such as aramid or rayon is appropriately employed.

  The band layer 10 is formed of, for example, one or more band plies in which band cords made of highly elastic organic fiber cords such as aramid and nylon are arranged at an angle of 5 degrees or less with respect to the tire circumferential direction. In the present embodiment, a pair of left and right edge band plies 10A that covers both ends of the belt layer 9 and a full band ply 10B that covers substantially the entire width of the belt layer 9 outside the edge band ply 10A and the belt layer 9 in the tire axial direction. Are combined.

  Such a band layer 10 restrains the belt layer 9 and improves steering stability and the like. Note that the band layer 10 may be composed of the edge band ply 10A or the full band ply 10B alone.

  Further, in the tire 1 of the present embodiment, as shown in FIGS. 1 and 2, an inner liner 13 that is arranged inside the carcass 6 and extends between the bead portions 4 of the tire lumen surface 12 in a toroid shape, And a chafer 14 having a raised portion 14A extending from the bead toe 4t and extending from the bead toe 4t to the tire lumen surface 12 in the tire radial direction.

  The inner liner 13 of this embodiment is configured by combining a first inner liner 13A disposed on the tire lumen surface 12 side and a second inner liner 13B stacked on the outer side. These first and second inner liners 13A and 13B are made of air-impermeable rubber such as butyl rubber including butyl rubber or a halogenated butyl rubber which is a derivative thereof, for improving the internal pressure retention of the tire. Useful.

  The first inner liner 13A straddles the bead portions 4 and 4 in a toroidal shape, and the inner end 13Ai in the tire radial direction is more in the tire radial direction than the outer end 14Ao in the tire radial direction of the rising portion 14A of the chafer 14. Terminates outside.

  On the other hand, the second inner liner 13B is disposed between the bead portions 4 and 4 in a toroidal shape outside the first inner liner 13A. The second inner liner 13B extends further inward in the tire radial direction than the inner end 13Ai of the first inner liner 13A.

  The chafer 14 includes the upright portion 14A, a base portion 14B extending over the bead bottom surface 4b of the bead portion 4, and a turn-up portion 14C that rises outward in the tire radial direction on the bead heel 4h side of the bead portion 4. Such a chafer 14 is useful for preventing rim displacement and increasing the rigidity of the bead portion 4.

  The chafer 14 is made of a fiber material or a rubberized body thereof. The fiber material is preferably a canvas made of highly elastic organic fibers such as aramid and nylon. The chafer 14 of this embodiment is formed by topping this canvas with rubber. Such a chafer 14 can improve the wear resistance of the bead portion 4 and can preferably suppress damage such as toe chipping.

  In the present embodiment, the inner end 13Ai of the first inner liner 13A and the outer end 14Ao of the raised portion 14A of the chafer 14 are separated from each other by a distance L1 of 2.0 to 23.0 mm along the tire lumen surface 12. Arranged. Further, the second inner liner 13 </ b> B extends to at least the bead core 5 through the outer side in the tire axial direction of the rising portion 14 </ b> A of the chafer 14.

  Such a tire 1 can prevent the inner end 13Ai of the first inner liner 13A and the outer end 14Ao of the chafer 14 from overlapping each other on the tire lumen surface 12 side, thereby forming a step in the bead portion 4. The formability of the tire can be improved. Further, it is possible to suppress the formation of a butt portion where the inner end 13Ai of the first inner liner and the outer end 14Ao of the chafer 14 are inferior to each other. Thereby, it can suppress that the butt | matching part of inner end 13Ai of the 1st inner liner and outer end 14Ao of the chafer 14 peels by the distortion at the time of driving | running | working, and can improve the durability of the bead part 4. FIG.

  Further, the second inner liner 13B can reliably cover the separation portion 15 between the first inner liner 13A and the chafer 14 through the outer side in the tire axial direction. Therefore, even if the inner end 13Ai of the first inner liner and the outer end 14Ao of the chafer 14 are separated as in the present embodiment, the internal pressure retention of the tire is not deteriorated.

  In order to effectively exhibit the above action, the distance L1 between the inner end 13Ai of the first inner liner 13A and the outer end 14Ao of the chafer 14 is preferably 7.0 mm or more, more preferably 10.0 mm or more. desirable. If the distance L1 is too small, the above effects may not be expected sufficiently. Conversely, if the distance L1 is too large, the internal pressure retention may not be sufficiently improved. From such a viewpoint, the distance L1 is preferably 17.0 mm or less, and more preferably 13.0 mm or less.

  The second inner liner 13 </ b> B may extend at least up to the bead core 5, but is preferably folded around the bead core 5. Thereby, the 2nd inner liner 13B can cover tire inner cavity surface 12 more certainly, and can improve the internal pressure maintenance nature of a tire effectively. The folded portion 13Bb of the second inner liner 13B extends on the inner side in the tire axial direction of the folded portion 14C of the chafer 14.

  The distance L2 between the outer end 13Bo in the tire radial direction of the folded portion 13Bb of the second inner liner 13B and the outer end 14Co of the folded portion 14C of the chafer 14 is preferably 5.0 mm or more, and more preferably 7.0 mm. The above is desirable. When the distance L2 is too small, a large rigidity step is generated in the bead portion 4 and the durability may be lowered.

Next, a method for manufacturing the tire 1 will be described.
In this manufacturing method, as shown in FIGS. 3A and 3B, a sheet-like composite sheet 16 in which an inner liner 13 and a chafer 14 are combined with a cylindrical molding drum 21, and a sheet-like carcass. A step of winding the ply 6P (hereinafter referred to as “winding step”), a step of extrapolating the bead core 5 to the outer peripheral surface of the carcass ply 6P shown in FIG. 4 (hereinafter referred to as “shaping step”), and including.

  In the winding step, after the composite sheet 16 is wound around the molding drum 21, the carcass ply 6P is wound.

  As shown in FIG. 3A, the composite sheet 16 includes a sheet-like first inner liner 13A disposed on the outer peripheral surface side of the molding drum 21 and a pair of sheets disposed on both sides in the axial direction thereof. And the first inner liner 13A and the second inner liner 13B disposed on the outer side in the tire radial direction of the chafer 14.

  In the present embodiment, in the winding step, the inner liner 13 and the chafer 14 are combined in advance on the outer peripheral surface of the molding drum 21, and the composite sheet 16 stocked in a roll shape is cut into a predetermined length. To be used. For example, as shown in FIGS. 5A and 5B, the composite sheet 16 includes a first inner liner 13A, a pair of sheet-shaped chafers 14 and 14 disposed on both sides thereof, and a first inner liner. When the liner 13A and the second inner liner 13B arranged outside the chafer 14 are respectively supplied to the calendar roller 24 at predetermined positions, as shown in FIG. 5B, the members 13A, 13B, and 14 Are integrated and formed continuously. The composite sheet 16 is wound and stored as a roll-like body 23 via a release sheet 25, for example.

  In the composite sheet 16, the chafer 14 is disposed at a distance L3 of 5.0 to 20.0 mm from both side edges 13At in the axial direction of the first inner liner 13A. The composite sheet 16 is provided with a second inner liner 13B so as to straddle the chafers 14 on both sides. Thus, the composite sheet 16 can be formed in a state where the first inner liner 13A and the chafer 14 are reliably separated without overlapping in the tire radial direction, so that even when the composite sheet 16 is wound as the roll-like body 23, the inner liner There is no wrinkle in 13.

  The thickness W1 of the first inner liner 13A and the thickness W2 of the second inner liner 13B are preferably 0.7 to 1.1 mm from the viewpoint of ensuring the internal pressure retention of the tire. Further, the thickness W3 of the chafer 14 is preferably 0.5 to 1.2 mm from the viewpoint of securing the rigidity of the bead portion 4.

  Next, as shown in FIG. 3B, a sheet-like first carcass ply 6A on the outer side of the composite sheet 16, and a sheet-like second arranged on the outer side in the tire radial direction of the first carcass ply 6A. The carcass ply 6B is wound around. In the tire 1 shown in FIG. 1, the first carcass ply 6 </ b> A has a larger width than the second carcass ply 6 </ b> B in order to shift the folded portions 6 a 2 and 6 b 2 in the tire radial direction.

  In the shaping step, the bead core 5 and the bead apex 8 are extrapolated to the outer peripheral surface of the carcass ply 6P and the outer region of the chafer 14. Thereafter, as shown in FIG. 4, the carcass ply 6 </ b> P and the like are bulged (shaped) by the bead holding portion 22 that holds the bead core 5 while reducing the axial distance of the bead cores 5 and 5. The carcass ply 6P is pressure-bonded to the inner peripheral surface of the tread ring 18 that has been previously kept on the outside in the radial direction. Thereby, the raw tire 17 is formed.

  The raw tire 17 is vulcanized and molded by a vulcanization mold in the same manner as in the past, whereby the tire 1 shown in FIG. 1 is manufactured. In addition, the level | step difference of the separation | spacing part 15 of 13 A of 1st inner liners and the chafer 14 will be lose | disappeared when the surrounding rubber flows in by being pressed by the bladder at the time of vulcanization | cure, and a molding defect may be suppressed.

  In such a manufacturing method, the first inner liner 13A and the chafer 14 are attached to the molding drum 21 in a state of being reliably separated without overlapping in the tire radial direction, so the chafer 14 and the first inner liner 13A It is possible to suppress the occurrence of a step due to the overlap. Thus, when the carcass ply 6P is attached and shaped into a toroid shape, generation of wrinkles or the like in the inner liner 13 is suppressed, and the moldability of the tire can be improved. Moreover, since the distance L3 between the first inner liner 13A and the chafer 14 is limited within the above range, molding defects due to insufficient rubber flow during vulcanization molding can be suppressed.

  Further, the distance L3 between the first inner liner 13A and the chafer 14 may have an error of 3 mm or less with the distance L1 (shown in FIG. 2) in the tire 1 after manufacture. For this reason, the distance L1 of the tire 1 can be set to 2.0 to 23.0 mm by setting the distance L3 to 5.0 to 20.0 mm. Thereby, the tire 1 formed by the manufacturing method of the present embodiment can improve moldability and durability while maintaining the internal pressure retention of the tire 1.

  In order to effectively exhibit the above action, the distance L3 is preferably 7.0 mm or more, and more preferably 10.0 mm or more. If the distance L3 is too small, the above effects may not be expected sufficiently. On the other hand, if the distance L3 is too large, the internal pressure retention of the tire 1 may not be sufficiently maintained. From such a viewpoint, the distance L3 is preferably 17.0 mm or less, and more preferably 13.0 mm or less.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A pneumatic tire having the basic structure shown in FIGS. 1 and 2 and having the inner liner and the chafer shown in Table 1 was prototyped using the manufacturing method of the present invention, and their performance was tested. The common specifications are as follows.

Tire size: 285 / 65R17
Rim size: 17 × 8.5J
Formulation of first and second inner liners: Butyl rubber First inner liner thickness W1: 0.9 mm
Second inner liner thickness W2: 0.9 mm
Chafer: Nylon fiber canvas rubberized body Chafer thickness W3: 1.1 mm
The test method is as follows.

<Moldability>
Each of the 600 test tires was manufactured, and the presence or absence of a step in the bead due to the occurrence of wrinkles in the inner liner and the damage to the bead due to insufficient rubber flow were visually confirmed and displayed as a percentage (%). did. The smaller the number, the better.

<Durability>
Each sample tire was assembled on the rim, filled with an internal pressure of 250 kPa, and run at a load of 14.35 kN and a speed of 100 km / h. The time until the tire was damaged was measured. The result is an index of the travel distance, and is displayed as an index with the value of Comparative Example 1 being 100. The larger the value, the better.

<Internal pressure retention>
Each test tire was assembled on the rim, filled with an internal pressure of 200 kPa and allowed to stand for 30 days, and the rate of decrease in internal pressure (%) was measured. The result is the reciprocal of the rate of decrease in internal pressure, and is expressed as an index with the value of Comparative Example 1 being 100. The larger the value, the better.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the tires and manufacturing methods of the examples were excellent in moldability. Moreover, it has confirmed that the tire and manufacturing method of an Example can improve durability and the internal pressure retention property of a tire.

5 Bead core 6P Carcass ply 13 Inner liner 13A First inner liner 13B Second inner liner 14 Chafer 16 Composite sheet 21 Molding drum L3 Distance

Claims (5)

A step of winding a composite sheet in which an inner liner made of a sheet-like and air-impermeable rubber and a chafer having a fiber material are combined around the outer peripheral surface of a cylindrical molding drum, and a sheet-like carcass ply;
A method of manufacturing a pneumatic tire, including a step of extrapolating at least a pair of bead cores on the outer peripheral surface of the carcass ply and shaping the bead core into a toroid shape,
The composite sheet includes a sheet-like first inner liner;
A pair of the chafers disposed at a distance of 5.0 to 20.0 mm from both side edges in the axial direction of the first inner liner;
A method for manufacturing a pneumatic tire, comprising: a sheet-like second inner liner that is disposed on the outer side in the tire radial direction of the first inner liner and the chafer and is bonded across the chafer on both sides.   The method for manufacturing a pneumatic tire according to claim 1, wherein the distance is 7.0 to 13.0 mm. A carcass having a carcass ply extending from the tread portion to the bead core of the bead portion through the sidewall portion;
An inner liner made of air-impermeable rubber disposed inside the carcass and extending in a toroidal manner between the bead portions of the tire cavity surface;
A pneumatic tire including a chafer having a fiber material including an upright portion extending from a bead toe and extending from the bead toe to the tire inner surface in a radial direction of the tire.
The inner liner includes a first inner liner on the tire lumen surface side and a second inner liner stacked on the outer side thereof,
An inner end in the tire radial direction of the first inner liner terminates on the outer side in the tire radial direction with respect to an outer end in the tire radial direction of the upper portion of the chafer, and a tire lumen surface from the outer end of the upper portion. Along with a distance of 2.0-23.0 mm,
The pneumatic tire according to claim 1, wherein the second inner liner extends at least to the bead core through the tire axially outer side of the upright portion of the chafer.   The pneumatic tire according to claim 3, wherein the second inner liner is folded around a bead core.   The pneumatic tire according to claim 3 or 4, wherein the chafer is a canvas chafer in which a canvas made of organic fibers is topped with rubber.

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