JP2003236949A - Method for manufacturing pneumatic tire and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a pneumatic tire having excellent drainage while inflating at a manufacturing time is prevented. <P>SOLUTION: A method for manufacturing the pneumatic tire comprises the steps of laminating an unvulcanized tread 12 on a outer peripheral surface of a band assembly 24, then first pressing the bottom of a first groove 26 and the bottom of a second groove 28 by a groove bottom stitcher roll 30, and pushing out air near the bottom of the groove between the tread 12 and the assembly 12. The method further comprises the steps of pressing the entire tread by using a wide stitcher roll, and pushing out the air of a part except the bottom of the groove between the tread 12 and the assembly 12. The method also comprises the steps of then charging a green tire in which the tread 12 is integrated with the assembly 12 in a mold, and vulcanizing to mold the tire. Thus, a skeleton provided on the inner peripheral surface of the mold is pressed to the first groove 26 and the second groove 28 to form a circumferential main groove for draining of a product tire. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire manufacturing method and a pneumatic tire, and more particularly to a pneumatic tire manufacturing method having a groove in a tread extending in a circumferential direction, and a pneumatic tire.

[0002]

2. Description of the Related Art In recent years, there is a great need for improving drainage performance, and as a technical measure, drainage grooves are relatively wide and deep and are arranged linearly in the tire circumferential direction.

[0003]

When the groove width is widened, in the conventional relatively flat molded green tread, the groove pattern (also referred to as rib or bone) of the mold presses the molded green tread during vulcanization. Therefore, the belt and the carcass just below the groove bottom may be wavy, which may impair the basic performance such as the ground contact performance of the tire.

In order to improve the corrugation of the belt and the carcass, there has been a technique of using a grooved raw tread in which a groove is previously formed in a portion of the mold where the groove type hits, but in the conventional production process of a raw tire, When the raw tread is attached to the tire case (band assembly), the raw tread is pressed with a relatively flat and wide pressing stitcher, so pressure does not act on the groove of the raw tread, and the gap between the raw tread and the tire case There was a problem that the air intervening in the groove could not come out just below the groove.

As a method for dealing with this defective air entry,
In the past, this was dealt with by devising the shape of the groove of the raw tread with groove, but in the end, the groove depth is made shallower to enhance the pressing effect by the pressing stitcher, and it is possible to prevent the corrugation of the belt and carcass. It was difficult to achieve both.

In view of the above facts, the present invention provides a pneumatic tire having excellent drainage property and a pneumatic tire capable of producing a pneumatic tire having excellent drainage property while preventing air from entering during raw tire production. It is an object to provide a manufacturing method.

[0007]

The invention according to claim 1 is provided with at least a pair of bead cores, a carcass extending over one bead core and the other bead core, and a reinforcing layer provided on an outer peripheral surface of the carcass. On the outer peripheral surface of the band assembly, a green tire is formed by pasting an unvulcanized belt-shaped tread member having a groove extending in a direction corresponding to the tire circumferential direction, to form a raw tire, and a tread of a product tire so as to face the groove. A method for manufacturing a pneumatic tire in which the raw tire is vulcanized by using a vulcanizing mold having a bone portion for forming a circumferential groove in an inner peripheral surface thereof, wherein the band-shaped tread member is the band assembly. After sticking to a three-dimensional shape, while pressing a groove bottom stitcher roll having a width dimension equal to or less than the width of the groove bottom of the groove, the groove bottom of the groove is pressed along the longitudinal direction. It is.

Next, the operation of the method for manufacturing a pneumatic tire according to claim 1 will be described.

The green tire is formed on the outer peripheral surface of a band assembly having at least a pair of bead cores, a carcass extending over one bead core and the other bead core, and a reinforcing layer provided on the outer peripheral surface of the carcass, in the tire circumferential direction. It is formed by adhering an unvulcanized belt-shaped tread member having a groove extending in the corresponding direction.

Here, after the band-shaped tread member is attached to the band assembly, the groove bottom is pressed along the longitudinal direction while rotating the groove bottom stitcher roll having a width dimension equal to or less than the width of the groove bottom. As a result, the air in the vicinity of the groove bottom between the band-shaped tread member and the band assembly can be reliably pushed out.

The green tire thus formed is loaded into a vulcanization mold, and the bladder provided in the vulcanization mold expands as in the conventional case, so that the outer peripheral surface of the raw tire becomes the inner peripheral surface of the vulcanization mold. The product tire is pressed and vulcanized at a predetermined temperature for a predetermined time to form a product tire.

Further, the ribs of the belt and the carcass can be prevented by making the skeleton of the vulcanization mold face and press the groove formed in the raw tread.

According to a second aspect of the present invention, in the method of manufacturing a pneumatic tire according to the first aspect, after pressing the groove bottom of the groove with the groove bottom stitcher roll, a portion other than the groove is pressed. , Is characterized.

Next, the operation of the pneumatic tire manufacturing method according to claim 2 will be described.

In the pneumatic tire manufacturing method according to the second aspect of the present invention, after the groove bottom of the groove of the belt-shaped tread member which is difficult to apply the stitcher is pressed by the groove bottom stitcher roll, the portion other than the groove of the belt-shaped tread member is pressed. Therefore, the air between the band-shaped tread member and the band assembly can be efficiently pushed out.

According to a third aspect of the present invention, there is provided the pneumatic tire manufacturing method according to the first or second aspect, wherein:
When the groove depth of the groove is d and the gauge of the belt-shaped tread member is T, the groove depth d is 10 to 10 mm of the gauge T.
The feature is that it is set within the range of 80%.

Next, the operation of the method for manufacturing a pneumatic tire according to claim 3 will be described.

If the depth d of the groove of the belt-shaped tread member is less than 10% of the gauge T of the belt-shaped tread member, the corrugation of the belt and the carcass just below the groove bottom cannot be eliminated.

On the other hand, if the groove depth d of the belt-shaped tread member exceeds 80% of the gauge T of the belt-shaped tread member, the groove bottom gauge of the belt-shaped tread member becomes too thin and the workability during molding is deteriorated. The invention according to claim 4 is the method for manufacturing the pneumatic tire according to any one of claims 1 to 3, wherein the strip-shaped tread member has: An air vent hole penetrating the belt-shaped tread member is formed in the groove bottom of the groove.

Next, the operation of the pneumatic tire manufacturing method according to claim 4 will be described.

When an air vent hole penetrating the belt-shaped tread member is formed in the groove bottom of the belt-shaped tread member, the air vent hole between the belt-shaped tread member and the band assembly when the groove bottom is pressed by the groove bottom stitcher roll. It becomes easy to discharge via the.

According to a fifth aspect of the present invention, in the method of manufacturing a pneumatic tire according to any one of the first to fourth aspects, the groove bottoms of the grooves are substantially flat, and the groove bottoms are substantially flat. The stitcher roll is characterized by having a constant diameter in the axial direction.

Next, the operation of the pneumatic tire manufacturing method according to claim 5 will be described.

By pressing the substantially flat groove bottom while rotating the groove bottom stitcher roll having a constant diameter in the axial direction, the entire groove bottom can be pressed uniformly.

A pneumatic tire according to a sixth aspect is characterized by being manufactured by the method for manufacturing a pneumatic tire according to any one of the first to fifth aspects.

Since the pneumatic tire according to claim 6 is manufactured by the method for manufacturing a pneumatic tire according to any one of claims 1 to 5, the belt and the carcass have no waviness, High drainage is obtained by the directional groove.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the pneumatic tire manufacturing method of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the tread 12 of the pneumatic tire 10 of this embodiment is provided with a circumferential main groove 14 and a circumferential main groove 16 which linearly extend along the tire circumferential direction. .

The tread 12 of this embodiment has a so-called cap-base structure composed of a tread side cap rubber 12A and a base rubber 12B arranged inside the cap rubber 12A in the tire radial direction.

On the inner side of the tread 12 in the tire radial direction, a belt 18 composed of a plurality of belt plies and a carcass 2 are provided.
0 and an inner liner 22 are provided.

Next, a method of manufacturing the pneumatic tire 10 will be described.

Reference numeral 24 shown in FIG. 2 is a belt 18, a pair of bead cores (not shown), a carcass 20 extending over one bead core and the other bead core, and an inner liner 2.
It is a band assembly consisting of 2 etc.

The unvulcanized tread 12 has a lower unvulcanized base rubber 12B and an upper unvulcanized cap rubber 12A.
Is.

The unvulcanized tread 12 is formed with a first groove 26 and a second groove 28 extending in the circumferential direction.

The groove bottom of the first groove 26 and the groove bottom of the second groove 28 are preferably flat.

As shown in FIG. 3, the unvulcanized tread 12
Is attached to the outer peripheral surface of the band assembly 24.

The unvulcanized tread 12 is attached to the band assembly 24.
After sticking to the outer peripheral surface of the first groove 26, first, while rotating the groove bottom stitcher roll 30, the groove bottom of the first groove 26 and the groove bottom of the second groove 28 are sequentially pressed in the groove longitudinal direction. Go.

As a result, the air near the groove bottom between the unvulcanized tread 12 and the band assembly 24 is pushed out.

The groove bottom stitcher roll 30 has a constant diameter in the axial direction, and the width t (see FIG. 3) is the groove bottom width w.
Is set within the range of 30 to 100%.

The groove depths d of the first groove 26 and the second groove 28 are 10 to 8 of the gauge T of the unvulcanized tread 12.
It is preferably set within the range of 0%.

As shown in FIG. 2, the unvulcanized tread 12
The groove bottom of the first groove 26 and the groove bottom of the second groove 28 of
A plurality of air vent holes 29 that penetrate the unvulcanized tread 12 are formed along the longitudinal direction of the groove.

The air vent hole 29 has a diameter of 0.5 to 1.5 m.
It is preferable to set the pitch m in the longitudinal direction of the groove to 5 to 50 mm.

By appropriately providing the air vent hole 29,
Unvulcanized tread 1 by groove bottom stitcher roll 30
When pressing the groove bottom of No. 2, the air near the groove bottom between the unvulcanized tread 12 and the band assembly 24 is removed by the air vent hole 29.
It becomes easy to push it out through the.

After pressing the groove bottom of the first groove 26 and the groove bottom of the second groove 28 while rotating the groove bottom stitcher roll 30, as shown in FIG. 4, the wide stitcher roll 32 is rotated. While pressing, the entire tread 12 is pressed to push out air in a portion between the unvulcanized tread 12 and the band assembly 24 other than the vicinity of the groove bottom.

The outer peripheral surface of the groove bottom stitcher roll 30 and the outer peripheral surface of the stitcher roll 32 are preferably smooth so that unvulcanized rubber does not easily adhere thereto.

As a result, all the air between the unvulcanized tread 12 and the band assembly 24 can be pushed out.

Then, as shown in FIG. 5, the tread 12
A green tire 10 'in which the band assembly 24 and the band assembly 24 are integrated is loaded into a mold 34, and vulcanization molding is performed by a conventional method.

A rib-shaped bone portion 36 for forming the circumferential main groove 14 and a rib-shaped bone portion 38 for forming the circumferential main groove 16 are formed on the inner peripheral surface of the mold 34. Has been done.

In the vulcanization step, the bladder 40 provided inside the raw tire 10 'expands, the outer peripheral surface of the raw tire 10' is pressed against the inner peripheral surface of the mold 34, and a predetermined temperature is set for a predetermined temperature. Is vulcanized.

Since the raw tread 12 is preliminarily formed with the first groove 26 facing the bone portion 36 and the second groove 28 facing the bone portion 38, the bone portion 36 and the bone portion 38 are formed. Even if the raw tread 12 is pressed, the belt 18 and the carcass 20 do not wavy, and a product tire having excellent uniformity can be obtained.

Since the air vent hole 29 is crushed by the pressure during vulcanization and disappears, it does not remain in the product tire.

[0052]

As described above, according to the method for manufacturing a pneumatic tire of the present invention, it is possible to efficiently manufacture a pneumatic tire excellent in drainage and uniformity while preventing air from entering during raw tire manufacturing. It has an excellent effect that it can.

Further, the pneumatic tire of the present invention is excellent in drainage and uniformity.

[Brief description of drawings]

FIG. 1 is a sectional view of a tread of a pneumatic tire obtained by a method for manufacturing a pneumatic tire of the present invention.

FIG. 2 is a cross-sectional view of an unvulcanized tread and a band assembly before being attached.

FIG. 3 is a cross-sectional view of a tread showing a state where a groove bottom portion of a raw tire is pressed by a groove bottom stitcher roll.

FIG. 4 is a cross-sectional view of a tread showing a state in which the tread surface portion of a raw tire is pressed by a stitcher roll.

FIG. 5 is a cross-sectional view of a green tire and a mold.

[Explanation of symbols]

10 pneumatic tires 10 'raw tire 12 treads 14 Belt-shaped tread member 16 circumferential main groove 18 Belt (reinforcing layer) 20 carcass 24 band assembly 26 First groove (groove) 28 Second groove (groove) 29 Air vent hole 30 groove bottom stitcher roll 34 Mold (vulcanization mold)

Claims (6)

[Claims] 1. An outer peripheral surface of a band assembly including at least a pair of bead cores, a carcass extending over one bead core and the other bead core, and a reinforcing layer provided on an outer peripheral surface of the carcass, corresponding to a tire circumferential direction. The unvulcanized band-shaped tread member having a groove extending in the direction to form a raw tire, and a bone portion for forming a circumferential groove in the tread of the product tire so as to face the groove is formed inside. A method for manufacturing a pneumatic tire in which the green tire is vulcanized and formed using a mold for vulcanization provided on a peripheral surface, wherein after the band-shaped tread member is attached to the band assembly, a groove bottom of the groove is formed. A method for manufacturing a pneumatic tire, which comprises pressing a groove bottom stitcher roll having a width dimension equal to or less than the width and rotating the groove bottom stitch along a longitudinal direction. 2. The method for manufacturing a pneumatic tire according to claim 1, wherein after pressing the groove bottom of the groove with the groove bottom stitcher roll, the portion other than the groove is pressed. 3. When the groove depth of the groove is d and the gauge of the belt-shaped tread member is T, the groove depth d is set within a range of 10 to 80% of the gauge T. The method for manufacturing the pneumatic tire according to claim 1, wherein the pneumatic tire is manufactured. 4. The band-shaped tread member is formed with an air vent hole penetrating the band-shaped tread member at the groove bottom of the groove. The method for producing a pneumatic tire according to item. 5. The groove bottom stitcher roll of claim 1, wherein the groove bottom is substantially flat, and the groove bottom stitcher roll has a constant diameter in the axial direction. Manufacturing method for pneumatic tires. 6. A pneumatic tire manufactured by the method for manufacturing a pneumatic tire according to any one of claims 1 to 5.