JPH05178002A - Tire for vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a vehicle tire having the following characteristics. Does not increase rolling resistance. The puncture resistance can be improved. It is possible to prevent the side portion from being damaged by foreign matter. [Structure] A vehicle tire is provided with a carcass layer having cord-shaped strips. The cords forming the cord-shaped strip are cover yarns. The cover yarn 10 is
The sheath yarn 12 made of high-strength fiber having higher tensile strength than the fibers forming the core yarn 11 is wound around the core yarn 11 to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle tire provided with a carcass layer having cord-shaped strips, and more particularly, it has improved puncture resistance and is resistant to side damage due to foreign matter on the rim or road. The present invention relates to a prevented vehicle tire.

[0002]

2. Description of the Related Art In recent years, vehicle tires have been required to be stable and capable of running at high speed and to be lightweight. Various methods have been conventionally used to reduce the weight of tires. Hereinafter, a wire-type bicycle tire will be described as an example of a vehicle tire.

As shown in FIGS. 3 and 4, a wire-type bicycle tire has a carcass layer 1 formed by providing vulcanizable rubber layers on both sides of a cord-shaped belt, and the cord of the cord-shaped belt has a cord. The carcass layers 1 are overlapped with each other, the tread rubber 2 is provided on the outer peripheral portion of the ground side of the carcass layer 1, and the tube 3 is provided inside the carcass layer 1. The cord-shaped strip is also called a so-called cord cloth, and is formed by aligning a plurality of cords.

Such wire-type bicycle tires are usually
It is manufactured as follows.

First, a cord-shaped strip having a rubber layer is cut into a bias shape and folded back at a portion corresponding to a tire bead 4 to form a carcass layer 1. Both ends of the cord-shaped strip whose both sides are folded back are overlapped with each other on the ground contact side of the tire to form an overlapped portion 5 made up of a total of 3 plies. The cord-shaped strips that are folded and overlapped are arranged so that the cords cross each other, and a raw case of the tire is created.
Next, tread rubber 2 on the ground side of the upper part of this raw case
The tire is obtained by vulcanization and molding under a predetermined condition.

When the thickness of the tread rubber 2 is reduced in order to reduce the weight of such a tire, there is a drawback that tire puncture due to sharp foreign matters such as nails and glass shards significantly increases during traveling on a road. When the thickness of the side portion 6 is reduced, the side portion 6 is likely to be damaged by foreign matter, and the side portion 6 is likely to be broken (cord is broken) due to friction between the rim and the cord.

As shown in FIG. 4, the tread rubber 6 and the carcass layer 1 are provided in order to prevent puncture at the ground contact portion of the tire.
A method of inserting a breaker 7 formed of a woven fabric or a knitted fabric using an aromatic polyamide fiber or a polyester fiber between the two is used. However, this method has drawbacks that the weight of the tire is increased by the amount of the breaker 7, running resistance is increased, and delamination between the breaker 7 and the tread rubber 2 is likely to occur. ..

To prevent damage to the cord due to friction with the rim, a method of attaching a bead chafer to the side portion 6 is used. With this method, damage to the side portion 6 is prevented. Nothing useful.

In order to solve the above-mentioned drawbacks, it was considered to use a cord obtained by interlacing aromatic polyamide fiber yarn and nylon filament one by one as a cord.
Since the aromatic polyamide fiber has a small elongation, it has a drawback that it is instantly cut when a strong impact acts on the cord-shaped strip, and the fiber has poor adhesiveness with rubber, which causes delamination. There is.

In Japanese Utility Model Application Laid-Open No. 60-168604, as shown in FIG. 5, a cord 15 constituting a cord-shaped strip is formed.
Around the core yarn 13 with excellent durability and impact resistance,
A technique of using a core yarn formed by winding a fiber 14 having excellent adhesiveness with a rubber composition is disclosed. Aromatic polyamide fiber yarn is used as the core yarn 13,
Cotton or aliphatic polyamide fiber is used as the fiber 14 having excellent adhesiveness with the rubber composition.

[0011]

According to the above publication, since the fiber having excellent adhesiveness with the rubber composition is used for the outer layer of the cord 15, the adhesiveness between the cord-shaped strip and the rubber composition is improved. However, since high-strength fibers such as aromatic polyamide fibers are used for the core yarn 13,
Although it has excellent puncture resistance in the early stages,
In particular, a bicycle tire used at a high internal pressure has a drawback that the core yarn is cut during repeated running.

The present invention has been made to solve this drawback, and its object is to prevent the increase of running resistance and to prevent the breaker from being used as in the case of using a conventional breaker. An object of the present invention is to provide a vehicle tire capable of improving puncture resistance due to foreign matter on the road and improving cut resistance of a side portion of the tire without causing delamination from the tread rubber.

[0013]

A vehicle tire according to the present invention is a vehicle tire provided with a carcass layer having a cord-shaped strip, wherein the cords forming the cord-shaped strip are around the core yarn. A cover yarn formed by winding a sheath yarn made of a high-strength fiber having a higher tensile strength than the fiber forming the core yarn, by which the above object is achieved.

When the cord 10 used in the vehicle tire of the present invention is a cover yarn, the tensile strength around the core yarn 11 is higher than that of the fibers forming the core yarn 11, as shown in FIG. It is formed by winding a sheath yarn 12 made of high-strength fiber. As the core yarn 11, a synthetic fiber filament can be used. Examples of the synthetic filaments include polyamide type (nylon filament), polyvinyl alcohol type (vinylon filament), and polyester type (polyester filament). In particular, aliphatic polyamide fiber or polyester fiber is preferable. The core yarn 11 may be untwisted, or 100 to
The inclusion may be improved by adding twists at a twist number of about 500 turns / m.

The sheath yarn 12 wound around or covered with the core yarn 11 is formed of a fiber having a higher tensile strength than the fibers forming the core yarn 11. Examples of such high-strength fiber include aromatic polyamide fiber, aromatic polyester fiber, ultrahigh molecular weight polyethylene, and a combination of two or more thereof. In particular, the sheath yarn 12 is preferably a short fiber of para-aramid or meta-aramid.

The core yarn 11 is preferably made of a fiber having a higher impact resistance than the fiber forming the sheath yarn 12.

When the cord 10 is formed of a cover yarn, the sheath yarn preferably has a single yarn twist coefficient of 2.0 to 5.0. If the twist coefficient of the single yarn is less than 2.0, the fibers may come off, and if it exceeds 5.0, the warp may occur.

However, the twist coefficient K was determined according to the following equation.

Twisting coefficient T = K × N ^1/2 T: Number of twists (times / inch) K: Twisting coefficient N: English cotton count Further, the twisting coefficient of the cover yarn is preferably 3.0 to 10.0. .. When the twist coefficient of the cover yarn is less than 3.0 and exceeds 10.0, the strength is weak, the elongation is large,
Moreover, the peel strength tends to increase.

Further, the spindle rotational speed at the time of manufacturing the cover yarn is preferably 200 to 1200 rpm. At that time, the twist number of the cover yarn is 5 to 50 times / inch. The coverage is preferably 50% or more.

The following cords are particularly preferable as the cords used in the present invention. 6-nylon filament (420d /
70f), a para-aramid yarn (Ne45 / 1) is twisted (S twist, twist coefficient 2 to 5), and a para-aramid yarn (Ne45 / 1) is twisted (Z twist, twist coefficient 2). ~ 5) Cover yarn.

A large number of cords having such a configuration are aligned to form a cord-shaped strip. For example, the warp of the cord-shaped band can be about 44 threads / inch, and the weft can be about 2 threads / inch. The cord-shaped strip used in the present invention can be used by subjecting the cord-shaped strip having the above-mentioned constitution to an adhesion treatment with a so-called RFL resin or the like made of resorcin-formaldehyde resin-latex, or without treatment. When the cord-shaped strip is used without treatment, if the high-strength fiber forming the sheath yarn is a staple-cut fiber in advance, the high-strength fiber causes fluffing, and the rubber layer is created by the anchor effect. It is possible to improve the adhesion between the cord-shaped strip and the cord.

A vehicle tire can be manufactured by using the above cord-shaped strip in the same manner as the conventional method shown in FIGS. 3 and 4.

The vehicle in which the tire of the present invention is used is not particularly limited, and examples thereof include a bicycle, a motorcycle, a passenger car and the like.

[0025]

[Function] By forming a cord by winding a sheath yarn formed of high-strength fiber around the core yarn, the stress acting on the cord is mainly supported by the core yarn, and the stress greatly acts on the sheath yarn. And thus prevent the high strength fibers from breaking. Furthermore, since the periphery of the core yarn can be covered and protected with the high-strength fiber, the puncture resistance and the cut resistance of the side portion can be remarkably improved. That is, by using a fiber made of an aliphatic polyamide or polyester, which has been widely used as a vehicle tire cord for many years, as a core yarn, and by using a cord around which high-strength fiber yarn is wound, puncture resistance and cut resistance can be obtained. At the same time as improving the property, it is possible to prevent cutting of the high-strength fiber during use.

[0026]

EXAMPLES The present invention will be described in detail below based on examples.

(Example 1) A yarn in which a staple fiber of aromatic polyamide is spun is wound around a spiral around a 420-denier multifilament single yarn which is a normal nylon tire cord (aliphatic polyamide cord), and twisted yarn. I made a cover yarn. 90 pieces of the cover yarns are aligned in parallel with each other within a distance of 5 cm to form cord-shaped strips, which are dipped in an ordinary RFL resin aqueous solution,
The adhesive treatment was performed by heating at 5 ° C. for 40 minutes. A vulcanizable rubber composition was evenly rubbed on both sides of the treated cord-shaped strip with a topping roll.

The cord-shaped strip having the rubber layer thus obtained was cut into a bias shape, and both ends thereof were folded back at portions corresponding to tire beads to form a carcass layer.

The folded back end portions of the cord-shaped strip form a lap portion of a total of 3 plies on the ground side of the tire. A large number of cord-shaped strips were arranged such that the cords were folded and overlapped in this manner so that the cords intersect with each other to prepare a raw case for a tire. Next, a tread rubber was attached to the grounding side of the upper part of the green case, and vulcanization molding was performed under predetermined conditions to prepare a wire type tire.

(Comparative Example 1) A wire type tire was prepared in the same manner as in Example 1 except that the cover yarn used in Example 1 was replaced with a nylon yarn of 420 denier multifilament single. did.

(Comparative Example 2) A raw case was prepared in the same manner as in Example 1 except that the cover yarn used in Example 1 was replaced by a nylon yarn of 420 denier multifilament single. In the center of the obtained case, a breaker made of woven polyester fiber,
The wire tire was prepared by arranging the tire over the entire circumference thereof, further adhering a tread rubber on the grounding side of the tire, and vulcanizing the tire under the same conditions as in Example 1.

COMPARATIVE EXAMPLE 3 Instead of the cover yarn used in Example 1, an aromatic polyamide fiber was used as a core yarn, and a nylon yarn of 105 denier multifilament single was twisted around the core yarn to form a cover yarn. Wire tires were prepared in the same manner as in Example 1 except that

(Comparative Example 4) A wire-type tire was prepared in the same manner as in Example 1, except that the cover yarn used in Example 1 was replaced by the spun-twisted yarn shown in Comparative Example 7 below. did.

Next, in order to see the usefulness of the tire according to the present invention, the tires obtained in Example 1 and Comparative Examples 1 to 4 were subjected to the following conditions: a load of 50 kg and a running speed of 20 km.
/ H, inclination angle 0 °, side slip angle 0 °, a road surface characteristic experiment was conducted to measure the rolling resistance value.

On the other hand, the tires of the same as JIS-K-63
On the basis of No. 02, the drum running test machine was run, and the separation condition of the tread part, the damage condition of the cord and the damage condition of the side part due to the rim were visually observed.

Each of the above tires was set in a tensile tester, and the force (puncture resistance) when the tire punctured with a razor blade having a blade length of 25 mm was measured for the tread portion and the side portion. The tread portion is shown as puncture resistance, and the side portion is shown as a side damage force due to foreign matter. The above results are shown in Table 1.

[0037]

[Table 1]

Example 2 <Structure of yarn> (1) Core yarn: 6-nylon 420d / 70f (untwisted) (2) Single yarn for sheath yarn: Para yarn aramid fiber (manufactured by Nippon Aramid Co., Ltd., trade name : Twaron, 1.5d, fiber length 40m
m) was spun by a known method to obtain a spun yarn of 45 count (English cotton count). This was twisted 23.5 times / inch in the Z twist direction (single yarn) to obtain a yarn having a twist coefficient of 3.5.

<Manufacturing Method of Cover Yarn> Using a double covering machine, the core yarn was run at 40 m / min in a spindle, and the sheath yarn single yarn was used as an intermediate layer for 21.0 times in the S twist direction. / Inch (spindle rotation about 800r.
p. m), and the outermost layer as the pressing yarn is further twisted at 15.0 times / inch (spindle rotation speed: about 560 rpm) in the Z twist direction, and 7. A No. 0 double covering thread was obtained.

The coverage of the aramid fiber of the obtained cover yarn was 60%. The twist coefficient of the cover yarn was as follows. Middle layer (floating yarn): 7.6, outermost layer (pushing yarn): 5.3.

The tenacity, elongation and peel strength of the cover yarn were measured and the results were as follows. Powerful: 4
550 g, elongation: 19.0%, peel strength: 240 g.

(Comparative Example 5) <Yarn structure> (1) Core yarn: 6-nylon 420d / 70f (untwisted) (2) Sheath yarn: Para yarn aramid fiber (1.5d, 40 mm) <Process for producing core yarn A roving aramid fiber is passed through a spinning machine through a back roller, a middle roller, and a front roller in sequence, while the 6-nylon filament yarn is supplied immediately before the front roller, and the 6-nylon filament yarn is bundled with the aramid fiber bundle. By spinning the composite so as to come to the center of the yarn, a 7.0-spun (English cotton count) spun yarn was obtained. This was twisted 10.6 times / inch in the Z twist direction (single yarn) to obtain a yarn having a twist coefficient of 4.0.

The strength, elongation and peel strength of this core yarn were measured and the results were as follows. Powerful: 332
0 g, elongation: 17.53%, peel strength: 180 g.

Comparative Example 6 <Structure of yarn> (1) Core yarn: para-aramid fiber 420d / 140f
(Untwisted) (2) Sheath yarn: 6-nylon 105d / 15f <Cover yarn manufacturing method> Para-aramid fiber 4 as core yarn
A double-covering yarn of 7.0 count in the same manner as in Example 2 except that 20d / 140f multifilament (untwisted) and 6-nylon 105d / 15f multifilament single are used for the sheath yarn single yarn. Got

The tenacity, elongation and peel strength of this cover yarn were measured and the results were as follows. Powerful: 45
60 g, elongation: 3.3%, peel strength: 250 g.

(Comparative Example 7) <Yarn structure> (1) Yarn (I): 6 nylon 420d / 70f (untwisted) (2) Yarn (II): Para yarn Aramid fiber (1.5d, 40m)
m) <Method for producing spun-twisted yarn> A roving aramid fiber is passed through a spinning machine separately to a back roller, a middle roller and a front roller in order, and 6-nylon filament is supplied immediately before the front roller to positively Both were spun separately, and twisted and spun (silospan-like spinning). This is twisted 10.6 times / inch in the Z twist direction (twisted yarn),
A yarn having a twist coefficient of 4.0 was obtained.

The tenacity, the elongation and the peel strength of this spun and twisted yarn were measured and the results were as follows. Powerful: 325
0 g, elongation: 15.3%, peel strength: 120 g.

(Comparative Example 8) <Yarn structure> (1) Yarn (I): 6-nylon, 420d / 70f (2) Yarn (II): Para-yarn aramid fiber (1.5d, 40m)
m) was spun by a known method to obtain 7.0-spun spun yarn. This is twisted 10.6 times / inch in the Z twist direction,
(Single yarn) A yarn having a twist coefficient of 4.0 was obtained.

<Method for producing twisted yarn> Using a ring twisting machine, the above yarn (I) and yarn (II) are twisted 10.0 times / inch in the S twist direction (twisted yarn), and the twist coefficient is 3.5. Got the thread.

The tenacity, elongation and peel strength of this yarn were measured and the results were as follows. Strength: 3668 g, elongation: 14.0%, peel strength: 180 g.

[0051]

As is apparent from the above, the vehicle tire according to the present invention can improve the puncture resistance without increasing the rolling resistance, and the interposition between the tread rubber and the carcass layer due to the arrangement of the breaker. It is clear that peeling does not occur and the cut resistance of the side portion due to foreign matter is significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a cord used in the present invention.

FIG. 2 is a schematic sectional view of a cord.

FIG. 3 is a schematic sectional view of a wire-type bicycle tire.

FIG. 4 is a partially cutaway perspective view of a wire-type bicycle tire.

FIG. 5 is a cross-sectional view of a cord used in a conventional tire.

[Explanation of symbols]

 1 Carcass Layer 2 Tread Rubber 3 Tube 4 Tire Bead 5 Stacking Part 6 Side Part 7 Breaker 10 Cord 11 Core Thread 12 Sheath Thread

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Yoshihide Miyaji, 1006 Kadoma, Kadoma City, Osaka Prefecture National Tire Co., Ltd. (72) Inventor Junzo Hirata 1-21-19 Sugiyamate, Hirakata City, Osaka Prefecture

Claims (1)

[Claims] 1. A vehicle tire having a carcass layer having cord-shaped strips, wherein the cords constituting the cord-shaped strips have a tensile strength around a core yarn as compared with fibers forming the core yarn. A vehicle tire, which is a cover yarn formed by winding a sheath yarn made of high-strength high-strength fiber.