JPH09291488A - Steel cord for reinforcing rubber article, and method and apparatus for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a steel cord for reinforcing a rubber article to be used as a reinforcing material for the rubber article, having improved corrosion resistance and workability on producing the rubber article. SOLUTION: This steel cord is composed of a central part prepared by parallelly arranging two element wires (a), (b) without twisting and an outer layer part prepared by winding 6-8 element wires (a), (b) wound around the central part. If a residual twist of the group of element wires of the center part is B (turn/5m) and that of the outer layer part is A (turn/5m) regarding the obtained steel cord for reinforcing a rubber article, the following relations are satisfied: 0.5<=A<=3 and 2<=A+B<=5. In the figure, (a) is an element wire of the outer layer part, (b) is an element wire of the central part, 1 is a spool, 2 is a wave-imparting apparatus for giving waves on the element wire (b), 3 is a roll having a small diameter, 4 is a tubular-type twisting machine, 5 is a rotor, 6 is a spiral-imparting apparatus for element wires on the outer layer, 7 is a twisting port, 8 is a steel cord winder and 9 is an oil applying apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel cord used as a reinforcing material for rubber articles such as pneumatic tires and conveyor belts, and more particularly to improving the corrosion resistance of the steel code and workability during rubber article production. The present invention relates to a steel cord for reinforcing a rubber article, a method for producing the same, and an apparatus for producing the same.

[0002]

2. Description of the Related Art Steel used for conventional pneumatic tires
In order to increase the cord tensile strength per cord diameter and to obtain good fatigue resistance, the rucor is a layered twist in which the wires are arranged so as to have a close-packed structure as shown in FIG. Steel cords are known. However, in the case of the close-packed code as described above, the gap between the wires of the outer layer is small and the rubber does not sufficiently enter the inside of the code. Therefore, if the code comes into contact with moisture, the inside of the code Moisture easily penetrates into the cord and corrodes the cord.

Therefore, it is possible to improve the permeability of rubber by making the wire diameter of the central part of the cord larger than the wire diameter of the close-packed structure so as to leave a gap between the wire wires of the outer layer. 56-10
No. 3092, or conversely, it is possible to reduce the number of wires in the outer layer portion so that a gap is provided between the wires in the outer layer portion.
No. 223503 has been proposed respectively. Further, Japanese Patent Application Laid-Open No. 4-304319 proposes to give two-dimensional unevenness to a rubber-reinforcing metal filament by a gear roll.

However, in order to improve the penetration of rubber into the inside of the cord by making the diameter of the wire in the central portion larger than the diameter of the wire in the outer layer portion, a step of preparing wires having different diameters is required. So it's not economical. In addition, when the diameter of the strand is increased, the tensile strength per cross-sectional area of the strand tends to decrease, which adversely affects the weight reduction of the article. Further, in a code in which the number of strands in the outer layer portion is reduced so that rubber easily enters the inside of the code, the strength of the code may be insufficient, which causes a problem in reinforcing the rubber article.

On the other hand, the layer-twisted cord in which the strands in the central portion are aligned in parallel without being twisted and the strands of the outer layer are wound around the strands tend to cause residual twist in the strands in the central portion.
FIGS. 2A to 2C show a case where the composite 12 which has been subjected to the calendering process in which a large number of cords are aligned in parallel and coated with rubber is cut into strip-shaped composites 13. The strip-shaped composite 13 using the steel cord is shown in FIG.
The curved portion 14 is generated at the corner portion shown in (c).
The strip-shaped composite bodies 13 are connected to each other to form a belt layer of a tire, for example, but since the warped portion is generated, workability of connecting the strip-shaped composite bodies 13 and tire molding is deteriorated.

[0006]

It is to be noted that the cord in which the core wire of the layer-twisted cord is corrugated and the core portions are not twisted, the rubber penetrates to the center portion. Although the corrosion resistance of the alloy is remarkably improved, residual twisting is more likely to occur in the central portion, and the warp of the corner portion of the strip-shaped composite material becomes remarkable, and by connecting this, a long sheet-like joint is formed. It was found that there is a problem in the work of manufacturing the sheet and the accuracy of joining the sheets. INDUSTRIAL APPLICABILITY The present invention reduces the warp of the corner portion of the strip-shaped composite, facilitates the work of joining the strip-shaped composite to manufacture a long sheet, and always maintains the joining accuracy of the sheet. The purpose is to raise it.

[0007]

The first aspect of the present invention relates to a structure of a steel cord for reinforcing a rubber article, which comprises a central portion in which two strands of wire are arranged in parallel without being twisted together. A steel cord consisting of an outer layer portion in which 6 to 8 strands are wound around the central portion, wherein the residual twist of the strands in the central portion is B (turns / 5 m), If the residual twist of the part is A (turns / 5 m), 1 ≦ A ≦ 3, 2 ≦ A + B ≦ 5
The steel cord is characterized by having the following relationship. Further, it is preferable that all the strands have the same diameter, and at least one of the strands in the central portion is two-dimensionally corrugated.

The second aspect of the present invention relates to a method for manufacturing a steel cord for reinforcing rubber articles, the first of which is to form a two-dimensional waveform by passing two strands of wire used in the center through a waveform imparting device. After being applied, it is wound around one supply spool, and then when 6 to 8 wires constituting the outer layer portion are wound around the center portion, a wire group in the center portion is moved from the supply spool to a flyer. It is characterized in that when it is led to the twisting wire machine, it is fed out so that the twisting direction of the wire group in the central part is opposite to the twisting direction of the outer layer part, and the wire of the outer layer part is wound around it at the twist opening. In the present invention, it is preferable that the central wire is drawn from each of the two supply spools and a waveform is imparted to the two wires by one corrugating device.

In addition, the second is that after the two strands used for the central portion are corrugated to the two strands by the corrugating device,
When winding the central wire around a small diameter roll and guiding it to the twisting machine, the twisting machine is operated after the wire located between the small diameter roll and the corrugating device is pre-twisted. The present invention relates to a method for producing a steel cord in which a wire for the outer layer is wound around the wire at the center at the twist opening.

In the second aspect of the invention, it is preferable that the strand of the outer layer is unwound from the supply spool disposed inside the stranding machine, and the strand is wound around the strand of the center at the twisting opening. .

Further, a third aspect of the present invention relates to an apparatus for manufacturing a steel cord for reinforcing a rubber article, comprising a central portion 2
Two feeders for feeding out two strands of wire, one corrugating device for shaping the two strands respectively, and the length of the twisting opening can be adjusted around the twisting machine 1 This is a manufacturing apparatus in which a set of small-diameter rolls, then a rotor containing a wire for the outer layer portion, a spiral forming device for the outer layer portion, a twisting port, and a winding device for the cord are sequentially arranged.

[0012] Further, the second is that two feeders for feeding out the two central wires, and corrugating the central wires 2
Table corrugating device, 2 sets of small-diameter rolls with the length of the twisting hole adjustable around the twisting machine, a rotor with a built-in outer layer wire, and an outer layer spiral This is a manufacturing device in which a shaping device, a twisting port, and a cord winding device are sequentially arranged.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The first steel cord of the present invention has two wires in the central portion and six to eight wires in the outer layer portion as shown in FIG. The reason is that when the number of strands in the central portion is two, it is possible to eliminate the formation of a gap through which moisture is transmitted. Furthermore, by imparting a waveform to the strands in the central portion, the frequency of contact between the strands can be reduced, so that the transmission of moisture is further suppressed. Since the strands in the central portion are not twisted, the twisting step in the central portion can be omitted, and the productivity of the twisted wire can be improved. Further, if the diameters of the wires forming the steel cord are all the same, the wire drawing process becomes simple and the steel cord can be manufactured economically.

When a large number of steel cords arranged in parallel are coated with rubber, the steel cord is rolled by a roll.
The composite material cut into strips and strips will be warped. This warping often occurs when the center part of the steel cord is not twisted, and when the center part is not twisted and the center wire is wavy, the center wire is The occurrence of curl of the composite is further increased due to the greater mobility.

In the present invention, in order to prevent warping of the composite, the residual twist A of the outer layer is
The range of 0.5 ≦ A ≦ 3 is set, and the residual twist of the entire steel cord is slightly affected by the residual twist B of the central portion. Therefore, A + B is set to the range of 2 ≦ A + B ≦ 5. This has led to the present invention by finding that warping of the composite can be prevented.

The term "residual twist" as used herein means a twist of elastic deformation of each wire group of the central portion and the outer layer portion in a steel cord state, and the outer layer portion or the central portion is removed. A twist that is released by doing.

Further, in the second invention, the above-mentioned steel
The present invention provides a method for manufacturing a rucode, which can be manufactured in one step or two steps.
In any case, the gist of the second invention is to apply two-dimensional wires to the center part in advance through a wave applying device such as a gear to give a two-dimensional waveform, and then to form 6 to 8 external layers. Is wound around the central part, and when it is introduced into the twisting machine, the group of wires in the central part is twisted in advance, and the wires constituting the outer layer part are wound around this.

In one embodiment of the production in two steps,
After corrugating two strands with a corrugating device,
Take up one spool so that the strands of the book are not twisted together. When manufacturing the steel cord, the corrugated wire is rolled out from the spool so that twist is introduced in the same direction as the twist direction of the steel cord or in the opposite direction. By doing so, the amount by which the central wire group is twisted when passing through the twisting machine can be adjusted. Further, the residual twist of the strands of the outer layer portion can be adjusted by adjusting a shaping pin of a shaping device that imparts a spiral shape for winding the strands of the outer layer portion.

In one embodiment of the production in one step,
After pulling out the two strands of wire and corrugating them with a corrugating device, they are led to a twisting machine for winding the outer layer through a roll of small diameter. Here, the central wire group twists with the rotation of the twisting machine, and the twist opposite to that entering from the exit of the twisting machine to the twisting mouth where the outer layer wire is wound is introduced,
The strands of the outer layer are wound around the strands of the center without twisting. And a small diameter roll centering around the twisting machine
The amount of residual twist in the center can be adjusted by changing the distance between the loop and the twisting hole.

Further, according to the third aspect of the invention, for example, in the apparatus manufactured in two steps, when the two corrugated element wires in the central portion are unwound from the spool, the steel cord is twisted. For example, two corrugated strands are fed out from the spool via a flyer so that a twist is introduced in the same direction or in the opposite direction. By doing so, the amount of twisting of the central wire group when passing through the twisting machine can be adjusted. On the other hand, the residual twist of the strands of the outer layer portion can be adjusted by adjusting a shaping pin of a shaping device that imparts a spiral shape for winding the strands of the outer layer portion.

In the apparatus manufactured in one step, the wire in the central portion is guided to the twisting machine for winding the outer layer portion through the roll having a small diameter, but the wire group in the central portion is twisted. Twisting occurs as the wire machine rotates, and a twist opposite to that entering the wire is exited from the wire twisting machine to the twisting opening where the wires of the outer layer are wound.
Then, the amount of residual twist in the central portion can be adjusted by changing the distance between the small diameter roll and the twisting opening. Since a small-diameter roll is intended to prevent backflow due to twisting, a roll diameter that sufficiently restrains the wire is desirable.

[0022]

The present invention will be described in more detail below. First, FIG. 4 shows an apparatus for manufacturing a steel cord for reinforcing a rubber article, which shows a first example (claim 8) of the third invention of the present invention. It is two supply devices (supply spool) for feeding out the two strands b of the part. Reference numeral 2 is a single waveform applying device that applies a waveform to each of the strands b and b. Next, the strand b is provided with a pair of small-diameter rolls 3, and then a rotor 5 as a tuber type twisting machine 4 in which the strand a of the outer layer is built in, and a spiral of the outer layer. This is a manufacturing device in which a shaping device 6, a twisting port 7, and a stilcor winding device 8 are sequentially arranged. In the figure, reference numeral 9 is an oil applying device, and a set of small-diameter rolls 3 can adjust the length D with the twisting port.

FIG. 5 shows an apparatus for manufacturing a steel cord for reinforcing a rubber article showing a second example (claim 9) of the third invention of the present invention, and FIG. 6 is a partially enlarged view thereof. Is. In the figure, reference numerals 1 and 1 denote two supply devices (supply spools) for feeding out two central wires b, b. And 2,
Reference numeral 2 is a pair of gears as a waveform applying device that applies a waveform to each of the wires b. Next, one set of small diameter rolls is provided for each of the wires a.
Rotors 3 and 3 and then a tuber type twisting machine 4 having a built-in outer layer wire a, a spiral forming device 6 for the outer layer, a twisting port 7, and a coil. This is a manufacturing apparatus in which the winding devices 8 of the cords are sequentially arranged.

Since the small-diameter roll 3 is intended to prevent backflow of twisting, a roll diameter that sufficiently restrains the wires b is desirable. For example, the diameter of the wire b is 0.34 mm. If so, the diameter of the roll 3 is preferably 50 mm or less. Further, when the knot of the wire in the central portion is passed, or when the twist flows back to the corrugating device due to the replacement of the roll or the like, the residual twist B cannot be adjusted within the scope of the present invention. After twisting the strand between the small-diameter roll 3 and the corrugating device 6 with an appropriate jig in advance, the twisting may be started. As yet another implementation method, after applying a twist to the strand wire between the corrugating device and the small-diameter roll in the same or opposite direction to the twist direction of the steel cord in advance using an appropriate jig. It is also possible to start the twisted wire, and by doing so, it is possible to adjust the amount B by which the central wire group is twisted when passing through the twisting machine.

(Manufacturing of steel cord according to claim 4) A 2 + 8 structure code having two corrugated wires at the center was manufactured. First, after unwinding the strands b and b from the supply spools 1 and 1 on which the strands are wound, and corrugating the two strands b and b at the same time by one or two corrugating devices 2, respectively. The two strands b, b are wound on one spool 10 so that they are not twisted together. When manufacturing the steel cord, as shown in FIG. 7, when the two corrugated wires b are unwound from the spool 10, the steel cord is used.
The two corrugated strands b, b are fed from the spool 10 via the flyer 11 so that a twist is introduced in the same direction as the twist direction of the cord or in the opposite direction. By doing so, it is possible to adjust the amount B of twisting of the central wire group when passing through the twisting machine 4. Then, the twisting machine 4 shown in FIG.
In particular, the residual twist of the wire group of the outer layer portion is passed by the following, and is retained by adjusting the shaping pin in the shaping device 6 that imparts a spiral shape for winding the wire a of the outer layer portion. The twist A can be adjusted.

(Production of Steel Code According to Claim 5) A 2 + 8 structure code having two corrugated wires at the center was produced. This manufacturing is carried out by the manufacturing apparatus shown in FIG. 4, in which the wires b and b are drawn from the two supply spools 1 and 1 around which the wires b and b at the center are wound, respectively, and one waveform is formed. After corrugating the two strands b, b by the applicator 2, the stranding machine 4 for winding the outer layer portion through the pair of small-diameter rolls 3 through the strands b, b at the central portion. Lead to. The central wire group is twisted as the twisting machine 4 rotates, and exits from the twisting machine 4 and the strands 7 of the outer layer are wound around the twisting port 7.
A twist opposite to that from the beginning is introduced, and the strands b of the central portion are not twisted together, but the strands of the outer layer portion are wound around the central portion. In this case, the twisting machine 4
By changing the distance D between the small-diameter roll 3 and the twisted hole 7 with the center as the center, it is possible to adjust the amount of residual twist of the wires b, b at the center.

(Production of Steel Code According to Claim 5) A 2 + 8 structure code having two corrugated wires at the center was produced. This manufacturing is carried out by the manufacturing apparatus shown in FIG. 5, in which the wires b and b are drawn from the two supply spools 1 and 1 around which the wires b and b at the center are wound, respectively, and two waveforms are provided. After corrugating the two strands b, b by the applying devices 2, 2, the strands b, b at the central portion are passed through the two sets of small-diameter rolls 3, 3 and the twisting machine 4 Before entering, the group of wires in the central part are aligned in parallel and guided to the twisting machine 4, and the strands 7 in the center are twisted by the twisting port 7 and the wires of the outer layer part fed out from the inside of the twisting machine 4 are wound around The wires a and a were wound to form a steel cord.

The twist A of the wire group of the outer layer portion is obtained by pulling the manufactured steel cord a certain length, for example, 5 m from the spool and fixing the end thereof, and then fixing the outer layer portion at the other end. The core wire was pulled out from the gap of the wire group of the outer layer part, and the cord of only the outer layer part from which the center part was removed was allowed to freely rotate to release the residual twist. The evaluation was performed by measuring the rotational direction and the rotational speed of the cord when releasing the residual twist.

Similarly, the residual twist B of the central wire group is
A fixed length of the manufactured steel cord, for example, 5 m is spread.
The winding direction and the number of rotations when the twist of the strand of the outer layer having the one end fixed was removed and the center was allowed to rotate freely and the residual twist was released were recorded. The rotation of the steel cord in the tightening direction was defined as the + direction, and the rotation of the steel cord in the loosening direction was defined as the − direction.

FIG. 8 shows the residual twist of the center portion and the outer layer portion of a steel cord having two strands of the corrugated wire around the center portion and eight strands of wire wound around the center portion. Is plotted on the horizontal axis, and the vertical axis is the sum (A + B) of the residual twist A of the outer layer portion and the residual twist B of the central portion. In the figure, the numbers marked with dots are the steel cords indicated by the experimental numbers shown below.

(Experiment No. 13) Experiment No. 13 is a conventional steel cord, and the structure of such steel cord has two steel strands having a diameter of 0.34 mm used in the central portion. Is unwound from two unwinding devices, and the wave pitch is 4.4 mm and the wave height is 0.55 mm by one wave imparting device.
After being subjected to the corrugation described in (1), it is led to a tuber-type twisting machine that is wound around the center part to form an outer layer part through a roll having a diameter of 70 mm. At this time, the distance (D) between the roll and the twisting hole centering on the twisting machine is 526 cm. Next, eight strands of 0.34 mm diameter steel cord wires arranged in the outer layer portion are guided to a twist forming device having a pin spacing of 13 mm to give a spiral shape for winding. The steel cord having a 2 + 8 structure was formed by winding it around the center with a post-twisting machine.

(Experiment No. 12) With respect to the above-mentioned conventional code (No. 13), the diameter of the roll was 70 mm to 5 mm.
The steel cord manufactured by changing the length to 0 mm was used as Experiment No. 1.
And 2.

(Experiment Nos. 11 to 9) The above-mentioned conventional example
The codes of Experiment Nos. 10 and 11 are those in which the pin spacing of the spiral shaping device was set to 15 mm and 17 mm with respect to the cord (No. 13) to control the residual twist of the outer layer portion. or,
Roll diameter is 50 mm, and the pin interval of the spiral forming device is 15
The code manufactured as mm is Experiment No. 9.

(Experiment Nos. 8 to 5) In addition to the same manufacturing conditions as the above-mentioned conventional code (No. 13), the distance (D) between the roll and the twisting port was changed to manufacture. D (cm) is 518,
507, 502, and 497 are designated as code experiment numbers 8, 7, 6, and 5, respectively.

(Experiment Nos. 4 to 2) Two corrugation shaping devices were used when corrugating two core wires.
Further, two rolls each having a diameter of 50 mm were used, and the distance between the roll and the twisting hole and the pin interval of the spiral forming device were changed. That is, the codes produced with D (cm) of 485, 485, and 502 and pin intervals (mm) of 13, 15, and 15 were designated as experiment numbers 4, 3, and 2.

(Experiment No. 1) In the code of Experiment No. 1, two corrugated strands are wound in a single spool so as not to be twisted. It is produced by feeding it through the flyer shown in FIG. 7 when it is fed, but it is produced by making the rotating direction of the flyer the opposite direction to the twisting direction of the outer layer portion.

As a result, no warped portion was observed in the strip-shaped composite compounded with rubber in the shaded area in the figure.

[0038]

EFFECT OF THE INVENTION The steel cord of the present invention has excellent corrosion resistance because rubber penetrates into the central portion, and since the corrugated wire is imparted to the central wire, the steel cord has a center portion due to repeated strain. Wires do not protrude from the rubber, and when manufacturing a rubber article, the strip-shaped composite of the rubber and the unvulcanized composite has no warp portion, so workability is improved and accuracy is high. Can be a product.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional steel cord.

FIG. 2 is a state diagram when a strip-shaped composite body using a conventional steel cord is cut.

FIG. 3 is a sectional view of a steel cord of the present invention.

FIG. 4 is an overall view showing a third apparatus for manufacturing a steel cord for reinforcing rubber articles according to the present invention (claim 8).

FIG. 5 is an overall view showing a third apparatus for manufacturing a steel cord for reinforcing rubber articles according to the present invention (claim 9).

6 is a partially enlarged view of the manufacturing apparatus shown in FIG.

FIG. 7 is a view showing an example of a supply spool at the time of manufacturing a steel cord according to claim 4.

FIG. 8 is a steel code of 2 + 8 structure,
FIG. 6 is a diagram in which the residual twist A of the outer layer portion is plotted on the horizontal axis, and the sum (A + B) of the residual twist A of the outer layer portion and the residual twist B of the central portion is plotted on the vertical axis.

[Explanation of symbols]

 a: Outer layer strand, b: Center strand, D: Small diameter roll and twist length, 1 ... Spool, 2 ... Corrugated strand b Waveform imparting device, 3 ... Small diameter roll, 4 ... Tubler type twisting machine, 5 ... Rotor, 6 ... Spiral forming device for strand of outer layer, 7 ... Twisting port, 8 ... Steel cord winding device, 9 ... Oil coating device, 10 ... Spool, 11 ... Flyer, 12 ... Unvulcanized steel cord and rubber Long body, 13 ... Strip-shaped composite body, 14 ... Warping part.

Claims (9)

[Claims] 1. A steel cord comprising a central portion in which two strands are arranged in parallel without twisting, and an outer layer portion in which 6 to 8 strands are wound around the central portion. If the residual twist of the wire group in the central portion is B (turn / 5 m) and the residual twist of the outer layer portion is A (turn / 5 m), then 0.5 ≦ A
A steel cord for reinforcing a rubber article, which has a relationship of ≦ 3, 2 ≦ A + B ≦ 5. 2. The steel cord for reinforcing a rubber article according to claim 1, wherein all the strands have the same diameter. 3. The rubber article reinforcing steel cord according to claim 1 or 2, wherein at least one of the wires in the central portion has a two-dimensional corrugated pattern. 4. A supply spun after applying two-dimensional waveforms to two strands used in the center through a waveform imparting device.
When winding the filament group of 6 to 8 outer layers around the central portion and then guiding the central filament group from the feed spool through the flyer to the stranding machine. A rubber article-reinforcing staple characterized in that the strands of the central portion are unwound so that the twisting direction is opposite to the twisting direction of the outer layer portion, and the strands of the outer layer portion are wound around the twisting opening.
How to make rucode. 5. After applying two-dimensional corrugation to the two strands used for the central portion through a corrugating device, when winding the central strand around a small diameter roll and guiding it to a twisting machine, a small diameter roll is used. -Before twisting the wire group located between the cable and the corrugating device, start the operation of the wire twisting machine, and wind the wire of the outer layer around the center wire at the twisting port. A method for producing a steel cord for reinforcing a rubber article, which comprises: 6. A rubber article-reinforcing steel sheet according to claim 5, wherein the strands at the center are drawn out from the two supply spools, and are corrugated to the two strands by one corrugating device. How to make rucode. 7. The wire according to claim 5, wherein the strand of the outer layer is unwound from a supply spool disposed inside the stranding machine, and is wound around the strand of the center at a twisting opening. A method for producing a steel cord for reinforcing a rubber article as described above. 8. A pair of feeding devices for feeding two strands in the central portion, followed by a corrugating device for shaping a corrugation on each of the two strands, and a stranding machine as a center for twisting. A set of small-diameter rolls that can adjust the length of the mouth, then a rotor with a built-in outer layer wire, a spiral forming device for the outer layer, a twisting port, and a winding device for the cord. An apparatus for manufacturing a steel cord for reinforcing rubber articles, which is characterized by being arranged. 9. A feeding device for feeding out two wires in the central portion, two corrugating devices for corrugating the wires in the central portion, and a length of a twisting wire centering around a twisting machine. , Two sets of small-diameter rolls that are adjustable, a rotor with a built-in wire for the outer layer, a spiral forming device for the outer layer, a twisting port, and a winding device for the cord. An apparatus for manufacturing a steel cord for reinforcing a rubber article, comprising: