JP2003039571A - Pneumatic tire manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize both of the improvement of uniformity and the enhancement of steering stability. SOLUTION: A narrow strip-like ribbon is arranged on the high rigidity core of a split mold almost in a tire widthwise direction, and the arranging direction of the narrow strip-like ribbon is almost reversed in both respective beads and transited in a tire periphery direction to be continuously wound to form a carcass ply. The narrow strip-like ribbon is spirally wound in the tire peripheral direction almost over the width of a tread surface on the outer peripheral side of the crown part of a carcass to form a belt layer, a narrow strip-like ribbon comprising a thin-walled rubber is spirally wound to form a rubber reinforcing layer, and the narrow strip-like ribbon comprising a rubber is spirally wound to form side wall parts and the tread surface part. A constituent part other than the above mentioned tire constituent part is formed if necessary by spirally winding the narrow strip-like ribbon, and a green tire is vulcanized by the vulcanizing mold of the split mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and particularly, it is an object of the invention to improve both uniformity and steering stability.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional pneumatic tire includes a tread portion 11, sidewall portions 12 extending inward in a radial direction from side portions of the tread portion 11, and sidewall portions. And a bead portion 13 provided on the inner peripheral side of 12 and extending toroidally between the bead cores 14 disposed in the respective bead portions 13 so that the side end portions are wound radially outward around the bead core 14. A carcass 15 including at least one returned carcass ply 15a, 15b with a rubber reinforcing layer, and a carcass 1
5 and at least one sheet located between the tread tread surface, and in the figure, a belt including a belt layer 16 with a rubber reinforcing layer.

[0003]

However, when manufacturing such a pneumatic tire, a sheet-like carcass ply 15a, 15b with a rubber reinforcement layer and a rubber reinforcement layer to which a rubber reinforcement layer (not shown) is attached in advance. Layer (not shown)
Sheet-like belt layer with rubber reinforcement layer 1
Since a green tire is molded using No. 6, a joint portion is formed in the carcass ply 15a, 15b with a rubber reinforcing layer, etc. over almost the entire area in the tire width direction, and the thickness of the joint portion is larger than the thickness of other portions. There was a problem that the tire uniformity would be deteriorated due to the inevitable consequence of becoming considerably large.

Further, in the conventional method for manufacturing a pneumatic tire, carcass plies with a rubber reinforcing layer 15a, 15a, 15a, 15 are provided on a molding drum having a diameter smaller than the inner surface shape of the product tire.
b and 16 were pasted to mold a green tire, and after the green tire was incorporated into a vulcanization mold having an inner surface shape that is approximately similar to the outer shape of the product tire and the diameter was expanded, vulcanization molding was performed. Carcass ply with rubber reinforcement layer, etc. 1
The rubber reinforcing layers in 5a, 15b and 16 are provided between the carcass plies and between the belt layers in the product tire (see FIG. 2).
In the example shown in, there is no corresponding part), or where it is to be located between the carcass ply and the belt layer, this rubber reinforcing layer, when the diameter is expanded, the carcass ply that sandwiches the rubber reinforcing layer, etc. In the product tire, the wall thickness of the rubber reinforcing layer is 0.
It is difficult to set the thickness to 5 mm or more, and therefore, it is impossible to achieve the excellent steering stability in the product tire because the rigidity of the tire crown portion cannot be adjusted in a wide range by the rubber reinforcing layer. There was also a problem. It should be noted that when the rubber reinforcing layer is crushed, it is also possible to achieve excellent steering stability in the product tire due to the fact that the belt rigidity distribution of the belt layer adjacent to the rubber reinforcing layer is disturbed and the belt rigidity distribution is not uniformed. There was a problem that it was not possible to realize sex.

The present invention is intended to solve such problems of the prior art, and its object is to prevent the occurrence of joints such as carcass plies during green tire molding. And improve tire uniformity, and between carcass plies,
The thickness of the rubber reinforcing layer located between the belt layers and between the carcass ply and the belt layer is 0.5 in the product tire.
It is to provide a pneumatic tire that achieves excellent steering stability by a new manufacturing method by setting the thickness to be equal to or greater than mm and preventing the belt layer cords from being disordered in arrangement.

[0006]

According to the method of manufacturing a pneumatic tire of the present invention, there are provided a tread portion, sidewall portions which extend inward in a radial direction and are continuous with side portions of the tread portion, and inside the sidewall portion. A carcass comprising at least one carcass ply extending substantially parallel to the tire inner contour, and a bead portion provided on the circumferential side, and at least one belt layer disposed between the carcass and the tread tread. Between the belt and the carcass plies, between the belt layers and between the carcass ply and the belt layer,
A method for manufacturing a pneumatic tire having at least a crown portion and a rubber reinforcing layer arranged with a thickness of 0.5 mm or more, the split tire having a surface shape equivalent to an inner surface shape of a product tire. On the core, along the surface shape of the core, a narrow strip ribbon in which one or more bundles of cords are covered with rubber is arranged substantially in the tire width direction, and at each of the bead portions, a small width is arranged. The process of forming a carcass ply by continuously reversing the disposition direction of the belt-shaped ribbon, making a transition in the tire circumferential direction, and forming a carcass ply, and after forming the carcass ply, on the outer peripheral side of the carcass crown portion, over the tread tread width A step of forming a belt layer by spirally winding a narrow strip ribbon in which one or a plurality of bundles of non-stretchable cords are covered with rubber in a substantially circumferential direction of the tire, A step of spirally winding a narrow strip ribbon made of meat rubber to form a rubber reinforcing layer; a step of spirally winding a narrow strip ribbon made of rubber to form a sidewall portion and a tread tread portion; A component other than the component, if necessary, has a step of spirally winding a narrow strip ribbon, and a step of vulcanizing the green tire with a split-type vulcanizing mold. .

In this pneumatic tire manufacturing method, one or a plurality of cords are provided along a surface shape of the split type high-rigidity core having a surface shape equivalent to the inner surface shape of the product tire. The narrow strip ribbon coated with a bundle of rubber is arranged almost in the tire width direction, and the arrangement direction of the narrow strip ribbon is substantially reversed in each of the bead portions to make a transition in the tire circumferential direction for continuous winding. Turn to form a carcass ply, and after forming the carcass ply, on the outer peripheral side of the crown portion of the carcass, a narrow strip ribbon in which one or more bundles of inextensible cords are covered with rubber is spread over the tread width of the tread. By forming a belt layer by spirally winding in the tire circumferential direction, no joint portion is generated in the carcass ply or the like when molding a green tire. , Over the entire circumference region of the tire, since it can be implemented with high accuracy desired the thickness, it is possible to improve the tire uniformity.

Further, in this pneumatic tire manufacturing method,
At the time of vulcanization, since it is not necessary to incorporate the green tire into a vulcanization mold having an inner surface shape that is approximately similar to the outer surface shape of the product tire and to expand the diameter, the rubber reinforcing layer is crushed between carcass plies and the like. In addition, the rubber reinforcing layer in the product tire has a thickness of 0.
It is easy to set the thickness to 5 mm or more, and therefore, due to the fact that the rigidity of the tire crown portion can be adjusted in a wide range by the rubber reinforcing layer, excellent steering stability can be realized in the product tire. Further, since the belt layer cords of the belt layer are not disturbed during the vulcanization, the belt rigidity distribution can be sufficiently uniformed, and thus excellent steering stability can be realized in the product tire. it can.

Therefore, in this method of manufacturing a pneumatic tire, the carcass ply, the rubber reinforcing layer and the belt layer are appropriately molded, and the vulcanization is also properly made.
It is possible to improve both uniformity and steering stability.

More preferably, in the method of manufacturing a pneumatic tire, vulcanization is performed together with the split type high rigidity core during vulcanization. According to this, a product tire can be manufactured with excellent accuracy in its dimensions.

Further, preferably, at the time of vulcanization, the split type high-rigidity core is removed from the green tire and vulcanization is performed using an inflatable bladder for vulcanization. According to such a pneumatic tire manufacturing method, as compared with the case of using a high-rigidity core,
It is possible to shorten the take-out time of the tire after vulcanization, which can improve the productivity.

[0012] Preferably, at least one of the bead core spirals formed by spirally winding the carcass ply before and / or after the formation of the carcass ply on the split high rigidity core is applied to the high rigidity core. Crimping to form a bead core. According to this, productivity can be improved as compared with the case of using the conventional method.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view in the tire width direction showing a pneumatic tire manufactured by a method for manufacturing a pneumatic tire according to the present invention,
In the figure, 1 is a tread portion, 2 is a sidewall portion, 3 is a bead portion, 4 is a bead core, 5 is a carcass, 6 is a belt, and 7 is a rubber reinforcing layer.

As shown in the figure, the pneumatic tire manufactured according to the present invention has a tread portion 1 and a tread portion 1.
Bead cores 4 formed on the respective bead portions 3 and each of which has a side wall portion 2 extending inward in the radial direction and connected to the side portion of the side wall portion 3 and a bead portion 3 provided on the inner peripheral side of the side wall portion 2. And a carcass 5 including at least one, here two, carcass plies 5a and 5b extending between the bead cores 4 substantially parallel to the inner contour of the tire.
And a narrow band-shaped ribbon in which one or more bundles of non-stretchable cords are covered with rubber over the width of the tread tread between the carcass 5 and the tread, and at least one ribbon is spirally wound in the tire circumferential direction. Here, a belt having one belt layer 6 and the carcass plies 5a and 5b and between the carcass ply 5a and the belt layer 6 are provided at least in the crown portion with a thickness of 0.5 mm or more. And rubber reinforcement layers 7a and 7b.

The method of manufacturing the pneumatic tire shown in FIG. 1 will be described below. That is, in manufacturing the pneumatic tire, first, on a split high rigidity core having a surface shape equivalent to the inner surface shape of the product tire,
Along the surface shape of the core, a narrow strip ribbon in which one or more bundles of cords are covered with rubber is arranged substantially in the tire width direction, and the narrow strip ribbon is arranged in each of the bead portions. Almost reverse the installation direction,
A carcass ply is formed by making a transition in the tire circumferential direction and continuously winding it, and then a bundle of one or more non-stretchable cords is covered with rubber around the tread tread width on the outer peripheral side of the carcass crown portion. A narrow strip ribbon formed by spirally winding the formed narrow strip ribbon in a tire circumferential direction to form a belt layer, and a narrow strip ribbon made of thin rubber is spirally wound to form a rubber reinforcing layer, and additionally, a narrow strip ribbon made of rubber. Is spirally wound to form a sidewall portion and a tread tread portion, and constituent parts other than the above tire constituent parts are formed by spirally winding a narrow strip ribbon, and finally a split type is formed. The green tire is vulcanized by the vulcanization mold.

When vulcanizing the green tire with the split type vulcanizing mold, even if the split type high-rigidity core is vulcanized together, the split type high-rigidity core is removed from the green tire. Vulcanization may be performed using an inflatable bladder for vulcanization.

By the way, in the above-described green tire molding step, at least one of bead core spirals formed by spirally winding before and / or after formation of the carcass ply on the split type high rigidity core. Can be pressure bonded to the high-rigidity core to form a bead core. For example, in the example shown in FIG. 1, the bead core helical body 4a is crimp-molded to the core before the crimp molding of the carcass plies 5a and 5b to the split type high-rigidity core, and after the carcass ply crimp molding is performed.
In this example, b is pressure-molded on the core.

According to the above pneumatic tire manufacturing method, when a green tire is molded, the formation of joints in carcass plies is prevented, tire uniformity is improved, and carcass plies, belt layers, and carcass plies are formed. The thickness of the rubber reinforcement layer located between the belt layer and the belt layer is 0.5 mm in the product tire.
With the above and by preventing the arrangement disorder of the belt layer cords, it is possible to provide a pneumatic tire that realizes excellent steering stability.

[0019]

EXAMPLES Next, regarding the tires of the examples actually manufactured by the applicant by the pneumatic tire manufacturing method according to the present invention and the conventional tires manufactured by the conventional manufacturing method, the tire uniformity and steering stability are shown. Each of the above was evaluated, and will be described below.

Here, each test tire has a size of 150.
/ 70R17 pneumatic tire for two-wheeled vehicle, the carcass is composed of two pieces of carcass ply composed of nylon cord and coated rubber, and the belt is composed of one belt layer composed of aramid fiber cord and coated rubber. did. In addition, regarding the example tire, while adopting the structure shown in FIG. 1, the width of the narrow band ribbon forming the rubber reinforcing layers 7a and 7b was set to 2 mm and the dimension in the tire width direction was set to 15 mm. The structure shown in FIG. 2 was adopted, and the thickness of the sheet-shaped rubber reinforcing layer 17 when attached was 2 mm.

The tire uniformity was measured by measuring RFV (Radial Force Variation), and the steering stability was measured by mounting each of the test tires on an on-road and off-road motorcycle of 1100cc. It was evaluated by the rider's feeling evaluation.

As a result, regarding the tire uniformity, the example tire had an RFV of 30% as compared with the conventional example tire.
Regarding the steering stability, when the conventional example tire was set to control (100), the example tire was 12
It was 0, and it was found that the tire uniformity and the steering stability were excellent.

[0023]

As described above, according to the present invention, both uniformity and steering stability can be improved.

[Brief description of drawings]

FIG. 1 is a tire width direction sectional view of a pneumatic tire manufactured by a manufacturing method according to the present invention.

FIG. 2 is a tire width direction sectional view of a pneumatic tire manufactured by a conventional manufacturing method.

[Explanation of symbols]

1,11 tread section 2,12 Sidewall part 3,13 bead part 4,14 bead core 4a, 4b bead core spiral 5,15 carcass 5a, 5b Carcass ply 6 belt layers 7,7a, 7b Rubber reinforcement layer 15a, 15b Carcass ply with rubber reinforcement 16 Belt layer with rubber reinforcement layer

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Claims (4)

[Claims] 1. A tire inner contour, comprising a tread portion, sidewall portions each extending inward in a radial direction in succession to a side portion of the tread portion, and a bead portion provided on an inner peripheral side of the sidewall portion. A carcass consisting of at least one carcass ply extending substantially in parallel, a belt consisting of at least one belt layer arranged between the carcass and the tread tread, between the carcass plies, between the belt layers. A method for manufacturing a pneumatic tire having a rubber reinforcing layer disposed with a thickness of 0.5 mm or more at least in a crown portion between a carcass ply and a belt layer, the method comprising: On a split high-rigidity core having the same surface shape, a narrow strip ribo in which one or more bundles of cords are covered with rubber along the surface shape of the core. While arranging substantially toward the tire width direction, substantially inverting the arrangement direction of the narrow belt ribbon in each of both bead portions, transition in the tire circumferential direction and continuously winding, to form a carcass ply After forming the carcass ply, a narrow strip ribbon, in which one or more bundles of non-stretchable cords are covered with rubber, is spirally wound substantially in the tire circumferential direction on the outer peripheral side of the crown portion of the carcass over the width of the tread surface. Forming a belt layer, spirally winding a narrow strip ribbon made of thin rubber to form a rubber reinforcing layer, and spirally winding a narrow strip ribbon made of rubber to form a sidewall and a tread. A step of forming a surface portion, and a step of forming a component portion other than the tire component portion as described above by spirally winding a narrow strip ribbon, The split-type vulcanizing mold, characterized by having a step for vulcanization of the green tire, the pneumatic tire manufacturing method. 2. The method of manufacturing a pneumatic tire according to claim 1, wherein the vulcanization is performed together with the split type high rigidity core. 3. The pneumatic tire according to claim 1, wherein the vulcanization is performed by removing the split type high-rigidity core from a green tire and using an expandable vulcanizing bladder. Tire manufacturing method. 4. A high-rigidity core is crimped with at least one bead-core helix that is spirally wound before and / or after formation of a carcass ply on a split-type high-rigidity core. The method for producing a pneumatic tire according to claim 1, wherein the bead core is formed.