KR100693082B1 - Cellulose-Steel hybrid Cord for Tire Reinforcement - Google Patents

Abstract

The present invention relates to a cellulose steel hybrid cord for reinforcing tires, which is positioned on a carcass of a tire so that the tire can support an external load while maintaining the internal air pressure, and a screw in which cellulose fiber is twisted to a predetermined pitch A core filament 10 having a shape and a side wire filament 20 having a carbon content of 0.7 to 0.9% by weight of carbon steel wrapped around the core tube 10 at a predetermined pitch; Has a 1 + 6 structure in which six sideline filaments 20 wrap around the core tube 10; The core portion 10, the screw pitch is 5 ~ 8mm, the screw rotation direction is characterized in that it is formed so as to be two directions with the twisting direction of the side line filament (20).

Therefore, when a frit occurs due to long-term use of the tire, only the core portion and the side filaments are not worn, so that the steel cord portion maintains sufficient reinforcing performance and the tire durability is increased.

Tires, hybrid steel cords, filaments, cores, frets, durability, screws

Description

Cellulose-Steel Hybrid Cord for Tire Reinforcement

1 is a configuration diagram showing various structures of a conventional steel cord.

2 is a perspective view showing a cellulose steel hybrid cord for tire reinforcement according to the present invention.

3 is a cross-sectional view of the cellulose steel hybrid cord for tire reinforcement of the present invention.

4 is a cross-sectional view showing the carcass of the tire to which the cellulose steel hybrid cord for tire reinforcement of the present invention is applied.

<Description of Symbols for Main Parts of Drawings>

10: core portion 20: side filament

30: carcass

The present invention relates to a reinforcement cord inserted into an elastic body such as rubber to increase strength. Particularly, the present invention relates to a cellulose steel for tire reinforcement, which is positioned at a carcass portion of a tire so that the tire can support an external load while maintaining the internal air pressure. It's about hybrid code.

As the problem of global environmental pollution has emerged as an important issue all over the world, research is being conducted in the automobile industry to improve the fuel efficiency of automobiles as well as the long-term use and regeneration of tires. Long-term use and reproducibility of a tire for an automobile is affected by the durability of the tire. In general, a reinforcement portion called a carcass is provided inside the tire to improve the durability of the tire. Carcass is basically essential for long-term use and to ensure that the cutting strength in use is maintained above a certain strength.

Therefore, steel cords are used in the carcass area, which is one of the major components of radial tires. Steel cord is widely used for reinforcing rubber products such as tires, high pressure hoses and conveyor belts because it has superior strength, modulus, heat resistance, and fatigue resistance compared to other inorganic and organic fibers.

Typically, steel cords used in tires are made by twisting a plurality of strands of metal filament, and coating a rubber layer thereon. Steel cord is usually coated with 0.1 ~ 0.4㎛ thick brass to improve adhesion to rubber on the surface of carbon steel with 0.6 ~ 0.95% by weight of carbon steel. It is made by twisting into a structure.

Figure 1 shows a number of steel cord structures, wire rods 1x3, 1x4, 2 + 2, 2 + 7, 1 + 6, 2 + 5, 2 + 6, 2 + 7, 3 + 6, 3 + 8 The cross section of the steel cord twisted by the structure of 3 + 9 and 3 + 9 + 15 is shown. The structure of such a steel cord is known through several existing patents, and each structure has different characteristics.

US Patent No. 3,032,963 discloses a commonly used steel cord two-layer lead 3 + 6 structure, and US Patent No. 3,336,774 discloses a steel cord two-layer lead 2 + 6 structure. However, the steel cord of the two-layered lead structure has a structure in which there is little gap between each side filament constituting the steel cord, so that the rubber layer does not penetrate into the steel cord. Therefore, when the steel cord having a two-layered lead structure is applied to a tire, there is a problem in that the steel cord is corroded due to moisture or salt penetrated into the tire, or the durability of the tire is rapidly reduced due to abrasion between the filaments.

Accordingly, U.S. Patent No. 4,586,324 proposed a 2 + 5 structure having a smaller number of sideline filaments than the existing 2 + 6 structure, and Japanese Patent Laid-Open No. 63-256782 compared a sideline filament with a conventional 3 + 9 structure. A small number 3 + 8 structure is proposed. However, the method of using the number of side filaments less than the conventional method is difficult to maintain the spacing between filaments uniformly in the stretching process of twisting the side filaments, so that the wide and narrow areas between the filaments are unevenly present. have.

In Japanese Patent Laid-Open Nos. 5-279973 and 8-13363, a spiral deformation is applied to one of three filaments constituting a core wire in a steel cord having a 3 + 6 structure in advance, and then together with the other two strands. The steel cord which improves rubber penetration force by extending the space | interval between sideline filaments by providing a twist and increasing the diameter of a core wire cord is proposed.

However, in this case, excessive stress is applied to the filament of one strand to which the spiral strain is applied among the core filaments, and thus the breakage of the filament is likely to occur, and only one strand of the core filaments is given the spiral deformation to give the gap between the side filaments Since the effect of widening is small, it does not have a significant effect on improving the rubber penetration.

The steel cord for tire reinforcement is formed in a multi-layered structure by obtaining a fresh material of carbon steel when applied to the carcass part, and in order to improve durability, it is to prevent abrasion due to fritting between the filaments forming the steel cord. It is important. That is, when the tire is used for a long time, fritting may occur between the filaments constituting the steel cord, and when the freting occurs, the filament may be corroded or disconnected, thereby weakening the strength of the steel cord. Accordingly, the strength of the carcass portion reinforced with the steel cord is weakened, and the durability of the tire is weakened.

In order to minimize this freting phenomenon, research is being conducted to disperse contact stresses between filaments while changing the contact between filaments into point contact, line contact, and surface contact. Methods of improving the penetrating force of rubber penetrated between sideline filaments when forming steel cords, which are disclosed in the above patents, correspond to the research results.

 However, the above method has a lot of difficulties in eliminating the wear phenomenon generated between the filaments. In other words, the frit between the core filament and the side filament of the side filament constituting a conventional steel cord can be alleviated to some extent, but has no effect on the frit between the core filament and the side filament.

In other words, the conventional steel cord has a problem in that the core filament and the side filament are formed of the same carbon steel, so that when the frit occurs between the core filament and the side filament, the side filament is abraded and the durability of the tire is weakened.

The present invention has been made to solve the above-described problems, to provide a cellulose steel hybrid cord for reinforcing tires that can minimize the frit between the side filament by forming the core and the side line made of a material of different strength. There is this.

That is, according to the present invention, the core portion is made of a cellulose material of low strength, and the side filament made of carbon steel is twisted around, thereby minimizing frets between the side filaments that substantially determine the strength of the cord, thereby improving tire durability. It is an object of the present invention to provide an improved cellulose steel hybrid cord for tire reinforcement.

In addition, the present invention is to form a core portion in a screw shape to reduce the contact area between the core portion and the side line filament and to allow more rubber to penetrate between the core portion and the side line filament, thereby reducing the friction between the core portion and the side line filament to improve durability It is an object of the present invention to provide a cellulose steel hybrid cord for tire reinforcement.

According to the cellulose steel hybrid cord for tire reinforcement of the present invention for achieving the above object, a screw-shaped core tube portion cellulose fiber (Cellulose Fiber) is twisted at a predetermined pitch, carbon steel material 0.7 ~ 0.9% by weight The wire rod of the side wraps around the core portion and includes a side filament of the twisted at a predetermined pitch; It has a 1 + 6 structure in which six side filaments wrap around the core portion, wherein the core portion has a screw pitch of 5 to 8 mm, and a screw rotation direction is formed in two directions with a twisting direction of the side line filament. It is done.

In addition, according to the cellulose steel hybrid cord for tire reinforcement of the present invention, the core portion is characterized in that the long axis and short axis is formed in an ellipse shape having a ratio of 8: 2.

In addition, according to the cellulose steel hybrid cord for reinforcing tires of the present invention, the side filament is a wire rod of 0.18 ~ 0.22mm in diameter, brass-plated to a thickness of 0.1 ~ 0.4㎛, and is produced through wet drawing. .

Further, according to the cellulose steel hybrid cord for tire reinforcement of the present invention, the side filament has a twist pitch of 10 to 12 mm; The core portion has a diameter in the range of 130-175% of the sideline filament diameter.

The above features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are based on the principle that the inventor can appropriately define the concept of the term in order to explain the invention in the best way. It should be interpreted as meanings and concepts corresponding to

2 is a perspective view showing a cellulose steel hybrid cord for tire reinforcement according to the present invention, Figure 3 is a cross-sectional view of the cellulose steel hybrid cord for tire reinforcement of the present invention, Figure 4 is a cellulose steel hybrid cord for tire reinforcement of the present invention Is a cross-sectional view of the carcass to which the tire is applied.

The cellulose steel hybrid cord for tire reinforcement according to the present invention includes a screw-shaped core tube portion 10 in which cellulose fibers are twisted at a predetermined pitch, and a carbon steel wire wraps around the core tube portion 10. And it comprises a side filament 20 of the form twisted at a constant pitch; It is formed in a 1 + 6 structure in which six side line filaments 20 wrap around the core barrel 10.

Here, the core portion 10 is formed in an elliptic shape with a long axis and a short axis having a ratio of 8: 2. In addition, it is preferable that the core part 10 has a screw pitch of 5 to 8 mm, and the screw rotation direction is two directions, in particular, a reverse direction to the twist direction of the side filament 20.

In addition, the side filament 20 is installed in a form in which a carbon steel wire having a carbon content of 0.7 to 0.9% by weight is twisted at a pitch of 10 to 12 mm while surrounding the core barrel portion 10. Moreover, the said side filament 20 is carbon steel of 0.20 mm in diameter, and the said core part 10 is a cellulose fiber of 0.35 mm.

At this time, the side line filament 20 may have a diameter of 0.18 ~ 0.22㎜, is brass-plated to a thickness of 0.1 ~ 0.4㎛, it is manufactured through a wet drawing (伸 線). In addition, the core portion 10, the outer diameter of the screw preferably has a diameter in the range of 130 ~ 175% of the diameter of the side line filament (20).

The cellulose steel hybrid cord for tire reinforcement of the present invention configured as described above does not reduce the reinforcing performance of the entire steel cord part because only the core tube is worn out when a frit occurs due to long-term use of the tire.

As the tire is used for a long time, the spacing between the steel cords of the carcass portion 30 becomes narrow, and friting occurs in the steel cords. At this time, the frit does not occur between the side filaments 20 formed of carbon steel, and the frit occurs only between the core tube 10 and the side filaments 20. In addition, when the freting occurs, when the core cell portion 10 made of cellulose and the side line filament 20 made of carbon steel are rubbed, only the core tube portion 10 made of cellulose fiber material, which is relatively hard, is worn out and the side line filament ( 20, the wear phenomenon does not appear.

At this time, since the core tube portion 10 is formed in a screw shape having an elliptical cross section, the contact area between the core tube portion 10 and the side line filament 20 is reduced, as well as the core tube portion 10 and the side line filament 10. More rubber penetrates in between, reducing friction between the core portion 10 and the sideline filaments 20. Therefore, the abrasion degree of the core part 10 is reduced, and the durability of the steel cord part is improved. And the side filament 20 which maintains the strength of a steel cord part hardly wears out, and the reinforcement performance of a steel cord part does not fall.

In addition, since the outer diameter of the screw of the core portion 10 is about 130 to 175% larger than the diameter of the outer side line filament 20, the core migration phenomenon that occurs in a steel cord for general tire reinforcement can be greatly improved. In addition, the interval between the sideline filament 20 is widened to improve the permeability of the rubber during tire production.

The following Table 1 shows the structure and fatigue resistance of the conventional general steel cord (comparative example) and the cellulose steel hybrid cord (invention example) for tire reinforcement of the present invention by using a RBT (Rotating Beam Tester, manufactured by Beaker) tester. Test result.

The cellulose steel hybrid cord for reinforcing tires used in the test used a screw outer diameter of the core portion 10 of 0.35 mm and a diameter of the side filament 20 of 0.20 mm, and in the case of a general steel cord of 0.20 mm of diameter. Was used.

division Comparative example Inventive Example rescue 1 + 6x0.20 1x0.35 + 6x0.20 Fatigue Life Cycle Test load: 90㎏ / ㎠ More than 2 million times More than 2 million times Test load: 130㎏ / ㎠ 65,000 More than 1.8 million times

Referring to Table 1, both the invention example and the comparative example had a fatigue life cycle of 2 million times or more at the test load of 90 kg / mm 2, but the fatigue life cycle of the comparative example was only 65,000 times at the test load of 130 kg / mm 2. On the other hand, the invention shows excellent fatigue resistance compared to conventional steel cords, such as showing a fatigue life cycle of more than 1.8 million times.

Therefore, it can be seen that the cellulose steel hybrid cord for reinforcing tires of the present invention exhibits more excellent effects in tires of a large vehicle such as a truck or a bus.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to such specific embodiments, and those of ordinary skill in the art are appropriately within the scope described in the claims of the present invention. Changes will be possible.

As described above, according to the cellulose steel hybrid cord for reinforcing tires of the present invention, when the frit occurs due to long-term use of the tire, only the core tube 10 is worn out and the sideline filaments 20 are not worn. The addition maintains sufficient reinforcement performance and has the effect of increasing the durability of the tire.

In addition, according to the cellulose steel hybrid cord for tire reinforcement of the present invention, the core tube portion 10 is formed in a screw shape, the contact area between the core tube portion 10 and the side line filament 20 is reduced, and the core tube portion 10 and the side line More rubber penetrates between the filaments 20, thereby reducing the friction between the core portion 10 and the sideline filament 20, thereby improving the durability.

In addition, according to the cellulose steel hybrid cord for tire reinforcement of the present invention, the outer diameter of the screw of the core tube portion 10 is large, which can improve core migration phenomenon, and the gap between the sideline filaments 20 is increased, whereby rubber penetration is improved. It works.

In addition, according to the cellulose steel hybrid cord for reinforcing tire of the present invention, even if the load is increased, it is possible to effectively extend the life of the tire when applied to the tire of a large vehicle, such as trucks or buses to maintain excellent fatigue characteristics.

Claims (6)

A screw-shaped core tube portion 10 in which cellulose fibers are twisted at a predetermined pitch, and a wire rod made of carbon steel having a carbon content of 0.7 to 0.9% by weight wraps around the core tube portion 10 at a constant pitch. Comprising a sideline filament 20 of twisted form; Has a 1 + 6 structure in which six sideline filaments 20 wrap around the core tube 10; The core barrel 10, the screw pitch is 5 ~ 8mm, the screw rotation direction is formed cellulose steel hybrid cord for tire reinforcement, characterized in that formed in two directions with the twisting direction of the side filament (20). The method of claim 1, The core barrel portion (10), cellulose steel hybrid cord for tire reinforcement, characterized in that formed in an ellipse shape having a long axis and a short axis of 8: 2. delete The method of claim 1, The side filament 20 is a wire rod having a diameter of 0.18 to 0.22 mm, brass-plated to a thickness of 0.1 to 0.4 μm, and cellulose steel hybrid cord for tire reinforcement, characterized in that is manufactured through wet drawing. . The method according to claim 1 or 4, The said side filament 20 has a twist pitch of 10-12 mm, The cellulose steel hybrid cord for tire reinforcement characterized by the above-mentioned. The method of claim 1, The core portion 10, the outer diameter of the screw cellulose steel hybrid cord for reinforcing tires, characterized in that the outer side has a range of 130 ~ 175% of the diameter of the side filament (20).

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