JPS6366959B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a steel cord for reinforcing rubber structures used as reinforcing materials for tires, conveyor belts, etc., and particularly relates to a multilayer steel cord for thick objects. Generally, this type of steel cord is constructed by twisting a plurality of wires together to form a strand, and then twisting a plurality of these strands together. A plurality of steel cords configured as described above are arranged in parallel and covered with a rubber material, and are used as reinforcing materials for tires, conveyor belts, and the like. In this way, when steel cord is used as a reinforcing material for rubber structures, the essential requirements are first of all that it has good chemical adhesion to the rubber material, and secondly, that it has good chemical adhesion to the rubber material. The rubber material penetrates well and the steel cord has elasticity in the longitudinal direction when embedded in the rubber material. That is, in order for the steel cord to fully fulfill its role as a reinforcing material for the rubber structure, it is important that the steel cord and the rubber material form a complete composite. For example, when a steel cord is used in a tire, if the adhesion between the steel cord and the rubber material and the penetration of the rubber material into the steel cord are poor,
When the car is running, the so-called separation phenomenon occurs, in which the steel cord and the rubber material separate, which significantly impedes the function of the tire and also causes moisture in the rubber,
Moisture that has entered through the cuts in the rubber causes rust in the wires of the steel cord, which has the drawback of significantly reducing the strength of the steel cord and accelerating the separation phenomenon. In addition, if the elasticity of the steel cord is low, the rubber material itself is a highly elastic material, so when the tire runs over a stone on the road surface, the steel cord will not follow the elastic deformation of the rubber material and will break. . However, in the conventional steel cord, as shown in Fig. 1 A and B, a plurality of wires 1 are twisted together to form a strand 2, and a plurality of these strands 2 are twisted together to form a steel cord 3. . In the above-mentioned steel cord 3, the strands 2 and each strand 1 are in close contact with each other, so when the steel cord 3 is covered with a rubber material, the rubber material does not penetrate to the center of the steel cord 3, and the inside of the steel cord 3 is A space A is created, and a space B is created inside the strand 2. In this way, since the rubber material did not enter the inside of the steel cord 3, the rubber material did not wrap around the entire circumference of the strand 1, and the adhesion between the steel cord and the rubber material was incomplete. Furthermore, the steel cord 3 was not fully satisfactory in terms of elasticity. The present invention was made to eliminate the above-mentioned drawbacks, and includes a group of wires made by twisting two wires together,
By twisting the above-mentioned wires and single wires with different wire diameters together to form a strand, and by twisting at least three or more of these strands together to form a steel cord, the three wires constituting the strand can be twisted together. The present invention provides a steel cord that allows the rubber material to penetrate without adhesion, and has elasticity in the longitudinal direction. Hereinafter, one embodiment of the present invention will be described based on the drawings. Example 1 As shown in Figure 2 A or B, the diameter is 0.175 mm.
Two strands 4 of diameter φ are twisted together to form an S twist with a twist pitch of 6.5 mm to form a strand group 5, and the above strand group 5 and a single wire 6 with a diameter of 0.25 mmφ are twisted to have a twist pitch of 13.0. mm, and are twisted together to form an S twist to form a strand 7 as shown in FIG.
Three or four of these strands 7 are twisted together to form a Z twist with a twist pitch of 13.0 mm to form the steel cord 8 shown in Figure 2 A and B. Next, Table 1 shows a comparison of the physical properties of the steel cord of the present invention in which the above strands are twisted together and a conventional steel cord having the cross-sectional shape shown in FIG. 1A.

【table】

[Table] As shown in Table 1, the steel cord of the present invention has a rubber penetration rate {(rubber penetration cross-sectional area/rubber penetration possible cross-sectional area) x 100}, compared to the conventional steel cord.
It is excellent in both fatigue resistance and elastic modulus. Example 2 As shown in FIG. 4A, seven strands 7 formed in the same manner as in Example 1 were used to adjust the twist pitch.
The steel cord 9 is constructed by twisting the 13.0 mm wires together to form a Z-twist. Next, Table 2 shows a comparison of physical properties conducted in the same manner as in Example 1.

[Table] As shown in Table 2, the steel cord of the present invention is superior to the conventional steel cord in terms of rubber penetration rate, fatigue resistance, and elastic modulus, similar to Example 1. . In the second embodiment, the strands 7 constituting the steel cord were all made of strands and single wires, but the present invention is not limited to this, and as shown in FIG. It is also possible to use a 1×3 structure and configure only the side strands using the strands 7 described above. In addition, the wires used in the present invention suitably have wire diameters in the range of 0.15 mm to 0.5 mm, and if necessary, copper alloy may be added to the surface of the wires for the purpose of improving adhesion to the rubber material. , plating with zinc, etc. By the way, in each of the above embodiments, the wire diameter ratio of the two strands 4 forming the strand group 5 and the single wire 6 twisted with the strand group 5 is set to 1:1.2 to 2.0 because If the wire diameter of the single wire 6 is smaller than 1.2 times the wire diameter of the strands 4, when the strands 5 and 6 are twisted together, the strength of the solid wire will be extremely weaker than that of the strands. However, since the single wire is wrapped around the strands (wrapping), the structure of the strand 7 cannot be obtained, and the tensile strength and elastic performance are poor. On the other hand, if it is larger than 2.0 times, the strength of the strands will be weaker than that of the single wire, resulting in the strands being wrapped around the single wire (wrapping), resulting in inferior tensile strength and elastic performance as described above. This is because there are drawbacks. Furthermore, the twisting direction or twisting pitch of the strands and cords should be selected as appropriate, and the twisting pitch should be the same in the process of twisting the strands → strands → steel cord, or the pitch should be set longer as the process progresses. However, it is preferable that the range is 5.0 mm to 20 mm. Furthermore, it is necessary that the two twisted strands and the single wire forming the strand are always twisted together; for example, one of the strands or the single wire is wound around the other; In other words, it must not be wrapped.
The reason for this is that in the wrapped state, when the steel cord becomes a steel cord, the longitudinal elasticity of the steel cord becomes extremely poor. Next, a method for producing steel cord using a buncher twisting machine will be described. Two strands of wire are introduced from one axis of the flyer of the bunchier wire twisting machine. The introduced strands are twisted together while rotating around the cradle and guided into the cradle from the other axis. At the same time, a single wire is introduced from the other axis and guided directly into the cradle. Since the two wire groups and the single wire twisted together as described above are introduced into the cradle from the axis of the flyer at the same time, both are twisted in the same direction as the wire group and twice as much as the twist direction of the wire group. They are twisted together in pitches to form strands all at once. A desired steel cord is constructed by twisting three or more of the above strands together using a buncher twisting machine. As described above, in the production of strands and steel cords, the use of a buncher twisting machine is extremely efficient, and allows the formation of strands and steel cords with a stable twisted structure. However, the production of strands and steel cords is not limited to the bunchier twisting machine, but also a cylindrical twisting machine, and it is also possible to use a combination of both depending on the occasion. As mentioned above, the steel cord of the present invention is completely different from conventional steel cords in its twist configuration, and has an extremely high rubber penetration rate, so it can be coated with a rubber material and used as a reinforcing material for rubber structures. If the steel cord and rubber material form a complete composite, the function of the steel cord is
Give your 100%. Furthermore, since the occurrence of rust due to moisture in the rubber can be prevented, the strength of the steel cord can be maintained for a long period of time. Furthermore, since it has excellent elasticity, it follows the elastic deformation of the rubber material well, and not only fully satisfies its function as a reinforcing material, but also has a remarkable effect against breakage.

[Brief explanation of drawings]

Figures 1A, 2B and 2C are cross-sectional views of conventional steel cords showing different configurations, and Figure 2 shows an embodiment of the steel cord of the present invention. Cross-sectional views, Figures 3A and 3B show strands in the steel cord of the present invention, A is a front view, and B is A-A in A.
The line sectional view and FIGS. 4A and 4B are sectional views showing other embodiments of the steel cord of the present invention, respectively. 1, 4...Element wire, 2,7...Strand, 3,8,
9...Steel cord, 5...Element wire group, 6...Single wire, 1
0...Core strand.

Claims (1)

[Claims] 1. A strand is formed by twisting together a group of strands formed by twisting two strands and a single wire having a strand diameter different from the wire diameter of the strands, and A steel cord made up of at least three strands twisted together. 2 The strand diameter of the single wire above is approximately 1.2 of the strand diameter of the strand group.
The steel cord according to claim 1, characterized in that the steel cord is increased by ~2.0 times.