JP3180324B2 - Steel code, method for producing the same, and tire using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel cord for reinforcing tires and the like, and more particularly to a steel cord having a 2 + 3 structure.
The present invention relates to a steel cord having a controlled code and excellent fatigue resistance and a method for producing the same.

[0002]

2. Description of the Related Art Steels used as reinforcing materials for tires are known.
The records are aligned in parallel in the calendaring process of tire manufacturing, coated with a sheet of rubber to form a composite with rubber (hereinafter referred to as trie), and then in a cutting process. The above-mentioned trie is cut obliquely with respect to the longitudinal direction of the cord at a predetermined interval to obtain a triat member.
The belt member is used as a belt-shaped strip material in which the side faces of the strip member are joined to each other and the steel cord is arranged obliquely to the length direction of the strip.

[0003] The steel cord used here usually has a residual torsion, so that if the restraint of the cord at the end of the trie is released at the time of cutting, the code is not used. It generates a force that tries to rotate in the circumferential direction of the cross section, and as a result
The jumping of the end of the member occurs. There is a problem that the side faces cannot be joined to each other in the next joining step in the case of the triangular member having such a shape in which the end portions are jumped up. If the degree of the bounce is not large, the bounce can be corrected manually for joining. However, there is a problem in that it takes time and effort to correct the bounce manually, and there is a problem in that a cord is driven into the joint (correction part). Disturbance is inevitable, and there is a problem in that the appearance is poor and the durability of the tire belt portion is reduced due to the poor appearance.

Normally, in a steel reinforcing steel cord, in particular, a 1 × n closed-type or open-type code, or an m + n-structured code is particularly provided on a belt portion of a passenger car tire. Is conventionally used. The latter cord having the m + n structure has the advantage of being excellent in rubber permeability even in a closed type, and has conventionally been manufactured with a buncher type twisting machine from the viewpoint of productivity.

[0005] A steel cord manufactured using a buncher type twisting machine has a high cordation because a twist is applied to a metal wire constituting the cord. Conventionally, as a method of reducing the codetion, based on the hysteresis loop theory shown in FIG.
A turbine 5 as shown in FIG. 2 has been used. FIG. 1 is a hysteresis loop showing the relationship between the input and output portions of a code, and FIG. 2 is a conceptual diagram of a buncher type twisting machine. In FIG.
"e" indicates the hysteresis at each step of the buncher-type twisted wire machine shown in FIG.

In this m + n structure code, the unwinding of the metal strands m which are not mutually twisted is installed outside the buncher flyer, and the unwinding of the other twisted metal strands n is unrolled. By installing it inside, an m + n structure is obtained. In FIG. 2, a metal wire m is unwound from a bobbin 1 outside a flyer, twisted with a first flyer 2, and then a second wire together with a metal wire n unwound from a bobbin 3 inside the flyer. By twisting with a flyer-4, the metal wire m is untwisted. On the other hand, by twisting the metal wire n, an m + n structure is formed. The twist is set by the turbine 5 and wound around the bobbin 7. Will be done.

In the case of this figure, the metal wire n unwound from the inside of the buncher flyer follows a conventionally known hysteresis loop, but the metal wire unwound from the outside of the buncher flyer. Line m is the first flyer
By (2), the twist is twisted at the same pitch in the direction opposite to the final code, and the twist is released again by the second flyer (4), so that the hysteresis loop has the shape as shown in FIG. In the figure, A is a hysteresis loop of the metal wire n unwound from the inside of the buncher flyer, and B is a loop of the metal wire m unwound from the outside.

That is, a metal wire n unwound from the inside of the buncher flyer and a metal wire m unwound from the outside are tarred.
When the same untwisting is applied using a bin, the hysteresis loop becomes as shown in FIG. 1, and the metal wire n unwound from the inside of the flyer and the metal wire m unwound from the outside by the Bauschinger effect. Has a large torsion difference. This is a fundamental problem in manufacturing and cannot be avoided as long as a m + n structure code is manufactured using a buncher type twisting machine.

For this reason, m + n cords manufactured using a buncher-type twisting machine are constituted by metal wires having greatly different tors. That is, the m + n code tones manufactured by the above-described method are in an extremely unstable state because they are formed by balancing metal wires having greatly different tones. For this reason, it is difficult to stabilize the code, and the problem that the end of the trim jumps up in the cutting process is likely to occur.

Further, for the above reasons, since the metal wires of the m + n code have greatly different torsions, flare is easily generated, and workability in the calendar process is very poor. When twisting with a buncher type,
There is also a problem that the amount of processing is larger than that of the blur type, and since the contact between the strands at the time of twisting is large, the metal strand is easily damaged and the fatigue property is reduced.

[0011]

The problem to be solved by the present invention is a typical one of the m + n-structured codes having a form in which the code is greatly reduced and which has excellent fatigue resistance. An object of the present invention is to provide a code having a simple 2 + 3 structure, a method for producing the same, and a tire using the code.

[0012]

The first aspect of the present invention is 2 + 3.
The code of the structure is such that the arrangement of the metal wires constituting 2 is such that the direction of the line connecting the center points of the metal wires in the code cross section does not change in the length direction of the code. And the arrangement of the metal wires constituting 3 is such that the rectangular circumscribed curve formed by the metal wires in the code cross section has a cross-sectional shape that does not change in the length direction of the code. The present invention relates to a characteristic steel code. Here, the above-mentioned cross-sectional shape can be obtained by making the molding rate of 2 smaller than the molding rate of 3 (1 or less). Further, by using a tuber type twisting machine, the cord is of the above-mentioned 2 + 3 structure having no residual torsion in the metal strand.

On the other hand, the second aspect of the present invention is a method for producing a steel cord having a 2 + 3 structure to be twisted by using a tuber twisting machine. The unwinding of the metal strands, which is located outside the brassier and which constitutes 3, is in the tuber, and then, when the metal strands are molded with a molding jig, Type 3
Is made smaller than the mold of the metal wire constituting
Are twisted together. Here, more uniform molding can be performed by attaching oil to the metal wires constituting the second wire. Then, the present invention provides a method of producing a steel code, wherein the twisted 2 + 3 structure code is passed through a straightness correction roller group while applying a high tension.

A third aspect of the present invention is a tire in which a steel cord having a 2 + 3 structure having the above-described features is used as a reinforcing material embedded in rubber, and is particularly applied to a belt layer of the tire. is there.

[0015]

According to the first aspect of the present invention, a cord having an m + n structure is produced by using a tuber type stranded wire machine, thereby reducing scratches entering a metal wire. Can, and
Since no twist is applied to the metal wire, the cordation can be further reduced.

In a tuber type twisting machine, when twisting a cord whose cross section is not symmetrical like the m + n structure, the arrangement of the m or n metal wires in the cross section of the cord is normal. It is not possible to place it in a non-uniform place, and it will be unevenly arranged in the length direction, and replacement of metal wires will occur,
Although a code having a normal m + n structure cannot be obtained, in the present invention, since the type of the metal wires of m is made smaller than that of n, the arrangement of the metal wires of each of m and n is arranged. Can be maintained in a normal position stably in the length direction.

In the code cross section, the arrangement of the metal wires corresponding to m is such that the direction of the line connecting the center points of the two wires in the code cross section changes in the length direction of the code. Therefore, the morphological and physical characteristics of the code such as straightness are excellent in the two strands. Accordingly, when the tire is buried in the tire belt portion, the driving interval is not disturbed, so that the uniformity of the tire is excellent.

On the other hand, in the metal wires constituting the wire 3, the rectangular circumscribed curve formed by the metal wires constituting the wire 3 in the code section does not change in the length direction of the cord. The metal wire of No. 3 has a normal spiral form, the tension load on each metal wire 3 can be made uniform, stress is not concentrated on a part of the metal wire, and the Since a gap can be provided between the metal wires, the contact force between the metal wires is reduced as compared to a compact cord having no gap made by buncher twist, and the durability during tire running is reduced. Will be improved. Further, in the twisted shape according to the present invention, the arrangement of the cords 2 and 3 in the cord cross section is obtained by making the molding ratio of 2 smaller than the molding ratio of 3. A gap is provided between the metal strands of the groups 3 and 3 and the rubber penetrates into the cord to eliminate the gap. Therefore, even if the tire is exposed to a moisture environment, rust is not generated. Does not occur.

[0019]

The present invention will be described more specifically below with reference to examples. The metal wire constituting the code is JISG 3506
SWRH82A or equivalent is used as the raw material steel, and the tensile strength previously drawn and heat-treated is 3
A wire having a wire diameter of 20 to 330 kg / mm ² and a diameter of 0.23 m was used. The produced codes were twisted at a constant twist pitch in a 2 + 3 structure.

The code is prepared by a tube as shown in FIG.
Bra - using the type of stranding machine 10, two metal wires hitting the m, Ju - unwound from the feeding apparatus 12 ₁ is installed on the outside of the probe 11, aligned drawn by focusing jig 13, This is passed through the tube outer wall 14 and the two metal wires are passed through one molding device 15 and then twisted with the metal wires constituting 3. Metal filaments constituting the 3 (n) is Ju - fed unwinding from the apparatus 12 ₂ is placed in the parts, which Ju - was guided to blanking the outer wall 14, of the individual to the individual metal wires Molding device 1
After passing through No. 6, the wire is twisted with a metal wire constituting No. 2. The twisted 2 + 2 structure and 2 + 3 structure codes are passed through a straightness correction roller group 17 and then wound up by a winding device 19. FIG. 4 is a front view of a molding device used in the present invention.

In the code according to the embodiment, a spindle oil was applied to the metal wire constituting 2 at the location of the focusing jig 13 by the oiling device 18. Next, the arrangement of the molding device 16 including the molding pins arranged in a zigzag pattern is different between 2 and 3, and the molding ratio of 2 is smaller than the molding ratio of 3. In addition, when the fiber was passed through the straightness straightening device 17 after being twisted into a 2 + 3 structure, the straightness was corrected by adding a tensile tension at the time of passing (15 kg / piece).

(Structure of Code) FIG. 5 is a side view showing a steel code according to the present invention.
A code section was observed for every four pitches. That is, the observation sites of the code are the AA line, the BB line, the CC line, and the DD line, and thereafter, this is repeated.

As shown in FIG. 6, in the AA line, two metal strands m are arranged in the vertical direction, and three metal strands n are shaped like a letter. And is located immediately above the metal strand m.

However, the BB line shown in FIG. 7 is located at a position 1/4 pitch ahead of the position of the AA line. There is no change in being located side by side in the direction. On the other hand, although the three metal strands n are in a U-shape, they are rotated by 90 degrees and are located on the right side of the metal strand m.

The line CC shown in FIG. 8 is a position advanced by 1/4 pitch from the position of the line BB. n is located immediately below.

Further, the DD line shown in FIG. 9 is a position which is further advanced by 1/4 pitch than the CC line, and is located on the left side with respect to the metal element wire m. Become.

FIG. 6 shows a metal element wire in the EE line.
Is the same as That is, the steel code of the present invention is characterized in that the positions of the metal wires m and n are different in each cross section, but the arrangement between the wires is the same. Has become.

On the other hand, the cross section of the steel cord shown in FIGS. 10 to 13 is based on Japanese Patent Publication No. 3-23673, and is a cross-sectional view at the same position as in FIGS. . However, in this conventional example, the positional relationship of the two metal wires m does not change, but the three metal wires n change greatly in the shape of a letter or a straight line. You can see that.

(Code Test) Embodiments 1 and 2 are examples of a code in a case where the molding ratio is changed, while Conventional Example 1 is an example of a code having a 2 + 3 structure using a buncher twisting machine. It is. In addition, Example 3 does not apply spindle oil, and Comparative Examples 1 and 2 do not newly add tension tension when passing through a straightness straightening device (7 to 8 kg / kg).
This is an example in which the type ratio is different.

The torsion of the cord was measured by pulling the cord from the reel 6 m with the terminal restrained, and then measuring the rotation of the cord when the terminal was released. Was evaluated. The torsion value was measured with the direction in which the cord was twisted as a positive value. The evaluation of the fatigue property was performed by belt bending according to the compression bending fatigue strength test specified in JIS standard L1017. The jump was measured by measuring the height of the edge when the trim after cutting was placed on a horizontal surface. The results are shown in Table 1 together with the production conditions.

[0031]

[Table 1]

As shown in Table 1, the cord according to the embodiment of the present invention has a significantly improved cordation as compared with the comparative example, reduces the jump of the triat, and has a scratch on the surface of the metal wire. And the workability in the calendar process can be improved.

[0033]

Since the cord according to the present invention does not have a residual torsion unlike the conventional cord, it is possible to prevent the end portion from jumping up at the time of trim cutting. It has excellent physical properties of the twisted shapes 2 and 3, and has a gap between the metal strands of the second and third groups, so that it has excellent fatigue resistance and can suppress the generation of rust, and is extremely industrially useful. is there.

[Brief description of the drawings]

FIG. 1 is a hysteresis loop showing a steel cord code made using a buncher type twisting machine.

FIG. 2 is a conceptual diagram of a buncher-type twisting machine.

FIG. 3 is a conceptual diagram of a tuber type twisting machine used in the present invention.

FIG. 4 is a front view of a molding jig.

FIG. 5 is a side view of the code of the present invention.

FIG. 6 is an illustration of the code AA of the present invention shown in FIG.
It is sectional drawing in a line.

FIG. 7 is an illustration of the code BB of the present invention shown in FIG. 5;
It is sectional drawing in a line.

FIG. 8 is a diagram illustrating the CC of the code of the present invention shown in FIG. 5;
It is sectional drawing in a line.

FIG. 9 is a DD of the code of the present invention shown in FIG. 5;
It is sectional drawing in a line.

FIG. 10 is a sectional view of a conventional code according to Japanese Patent Publication No. 3-23673 at the same position as that of FIG. 6;

FIG. 11 is a sectional view of a conventional code according to Japanese Patent Publication No. 3-23673 at the same position as in FIG. 7;

FIG. 12 is a sectional view of a conventional code according to Japanese Patent Publication No. 3-23673 at a position similar to that of FIG.

FIG. 13 is a sectional view of a conventional cord according to Japanese Patent Publication No. 3-23673 at the same position as that of FIG. 9;

[Explanation of symbols]

10 ‥‥ Chu - Bra - type twisted machine, 11 ‥‥ Ju - Bed, 12 _1, 12 ₂ ‥‥ unwinders, 13 ‥‥ focusing jig, 14 ‥‥ Ju - Bed outer wall, 15, 16 ‥ ‥ typed device, 17 ‥‥ straightness correction device (b - La group), 17 _1, 17 ₂ ‥‥ tensioning Russia - la, 18 ‥‥ oiling device, 19 ‥‥ retractor, m ‥‥ metal filaments , N} metal strand.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Saito 800 Shimononakano, Kuroiso City, Tochigi Prefecture Bridgestone Bekaert Steel Co., Ltd.Tochigi Plant In the Tochigi factory of Dedo Co., Ltd. (56) References JP-A-4-370283 (JP, A) JP-A-2-127581 (JP, A) JP-A-62-125083 (JP, A) 128689 (JP, U) Actually open 1986-82995 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) D07B 1/06-1/10 B60C 9/00

Claims (5)

(57) [Claims] 1. A code having a 2 + 3 structure, wherein the arrangement of metal wires constituting 2 is such that the direction of the line connecting the center points of the metal wires in the code cross section is the length of the code. And the arrangement of the metal wires constituting 3 does not change in the longitudinal direction of the cord, because the circumscribed curve of the V-shape formed by the metal wires in the code section does not change. A steel code having a cross-sectional shape. 2. The steel according to claim 1, wherein the molding rate of 2 is smaller than 1 (less than 1).
Record. 3. The steel code according to claim 1, wherein the metal strand has no residual torsion. 4. A method of producing a steel cord having a 2 + 3 structure to be twisted by using a tuber twisting machine, wherein the unwinding of the metal wire constituting 2 is installed outside the tuber. And the unwinding of the metal wire constituting 3 is provided in the tuber, and when shaping the metal wire with the shaping jig, the metal wire forming 2 is replaced by the metal forming 3 Making the strands smaller than the mold, then twisting the two and three metal strands, and then passing the straightened straightening rollers while applying high tension to the twisted 2 + 3 structural code. A method for producing a steel code. 5. A tire using the steel code according to claim 1 as a reinforcing material.