JPH07279067A - Steel cord for rubber-reinforcement and its production - Google Patents

Abstract

PURPOSE:To produce a single-layered steel cord for rubber-reinforcement having good impregnating property of rubber to the core part of the cord, high adhesivity to rubber and strong compressive strength in the axial direction of the cord and exhibiting excellent fatigue resistance. CONSTITUTION:This steel cord has a 1Xn structure produced by twisting three or more element wires in the same twisting direction and equal twisting pitch. Parts (a) free from crossing wires and parts (b) containing crossed wires are sporadically distributed in the longitudinal direction of the cord. An I-shaped opening (c) is formed by the crossing of the element wires and the cross-section perpendicular to the longitudinal direction of the cord is gradually varied to sporadically form opened contours.

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 for reinforcing rubber products such as automobile tires and belts and a method for producing the same.

[0002]

2. Description of the Related Art Generally, a steel cord has a structure in which a plurality of strands (filaments) are twisted together, is covered with a rubber material, and is used as a reinforcing material for rubber products such as tires and belts. . There are various types of steel cords, but a so-called 1xn bunched cord in which multiple strands are twisted in the same twisting direction and the same twisting pitch is often used because of its cost advantages. It is in. By the way, in order for such a steel cord to sufficiently fulfill its role as a reinforcing material, it must be a complete composite with rubber. For example, in an automobile tire, if the steel cord and the rubber are not completely adhered to each other, a peeling phenomenon between the steel cord and the rubber occurs during running. In addition, water entering from the outside causes rust on the steel cord, which significantly reduces the cutting load of the steel cord and accelerates the peeling from the rubber, which is a cause of significantly impairing the tire function. In order to deal with such a problem, it is necessary to infiltrate the rubber to the center of the steel cord and to make the rubber adhere well to the outer circumference of the wire, but in the ordinary bunched cord, it is necessary to Unless preformed, the strands have a compact form in which the wires do not intersect and are arranged in parallel. For this reason,
There is a problem that rubber penetration and rubber adhesion tend to be insufficient. As measures against this, conventionally, a plurality of strands are twisted loosely, a core strand is increased in diameter to form a minute gap between the side strands, and a side strand It is proposed that the number is reduced and a large gap is formed.

However, even if such prior art is theoretically disregarded, when actually manufacturing a steel cord, there are many situations where one wire is in contact with another wire at only one point, and twisting occurs. There are many places where the rubber becomes instable, the gap between the individual wires is not constant, and there is a biased state on one side, which lowers the mechanical properties of the wire assembly, or the rubber penetration is poor. It has been found that there is a problem in efficiency as a reinforcing material such as existing. Furthermore, in the prior art, when a compressive force acts in the axial direction of the cord, the mutual restraining force of the strands against the compressive force cannot be expected, so that a plurality of strands presents a so-called birdcage shape that opens in all directions. There is a problem that it is easy and the buckling property is poor. Also, in the calendering process for forming the carcass layer, belt layer, chafer layer, etc., if the steel cord is cut to the required length, the strands are likely to come apart, making it difficult to handle or embedded in the rubber layer. There is also a problem that when the wire of the cord is broken, there is a risk that the broken wire breaks through the rubber layer and sticks out.

A steel cord having 9 or more strands is usually made by a two-step twisting method in which a core strand is twisted and the outer strands are twisted around this.
Japanese Examined Patent Publication No. 4-13473 discloses two layers (3 + 9 structure) and three layers.
A bunched code of a multi-layer steel cord such as a layer (3 + 9 + 15 structure) has been proposed. In this prior art, the diameter of the coil formed by the individual strands is changed along the cord center line in order to prevent the strands of the core, that is, the center layer from coming off. Or it is designed to be on the outer layer. However, although this prior art can increase the pull-out resistance of the central layer to some extent, it is a so-called closed contour type in which the cross section perpendicular to the cord longitudinal direction is specified as a polygonal shape, and the cord does not open to the outside. Therefore, there is a problem that the rubber permeability is deteriorated. Also, since it is a multi-layer structure, the strand lengths of the central layer and the outer layer are quite different, and therefore, when a tensile load is applied, a large load is applied to the strands of the central layer,
There was a problem that the fatigue property was reduced.

The present invention was devised to solve the above-mentioned problems, and its purpose is to have good rubber penetration into the center of the cord and good adhesion to the rubber. It is an object of the present invention to provide a single-layer type steel cord for rubber reinforcement which is strong against compression pressure in the axial direction of the cord and has good fatigue resistance. Another object of the present invention is to provide a method by which a steel cord having the above characteristics can be manufactured easily, efficiently and economically.

[0006]

In order to achieve the above object, the present invention provides a single-layer steel cord having a 1 × n structure in which three or more wires are twisted at the same twist direction and at the same twist pitch. The cords that do not intersect each other and those that intersect each other coexist in the longitudinal direction of the cord, and the intersection of the strands creates an eye-shaped opening, and the cross section at right angles to the cord longitudinal direction changes sequentially, forming open contours everywhere. It is configured. In the steel cord according to the present invention, in addition to the portion in which the wires are arranged in parallel, the wires move from the cord outer diameter side to the cord center side and move again to the cord outer diameter side, or from the cord center side to the cord. There is a predetermined frequency of intersecting portions such that the wires move to the outer diameter side and move again to the center side of the cord, or adjacent wires on the outer diameter side are exchanged with each other. In the relationship between the cord length L and the twist pitch P, the number of strands n is 3 ≦ 3.
When n ≦ 6, the range of 0.5 ≦ (F × P) /L≦4.0,
More preferably, it is in the range of 0.5 ≦ (F × P) /L≦2.0. When the number of strands n is 7 ≦ n ≦ 19, 0.5 ≦
From the range of (F × P) /L≦15.0, 1.0 ≦
It is in the range of (F × P) /L≦10.0. The number of strands may be 20 or more, for example 27 or 36. However, as the number of strands increases, an open contour region is less likely to be formed in a cross section perpendicular to the cord longitudinal direction, and rubber permeability deteriorates. Therefore, 19 or less is preferable. The crossing of the strands includes crossing of the cord outer diameter side strands and crossing of the cord outer diameter side strands and the cord center side strands, and two or more adjacent strands are parallel to each other. This includes the case where the wire still intersects with one or more other wires. Further, the present invention has a 1 × n structure in which three or more strands are twisted at the same twist direction and at the same twist pitch, and a portion where the strands do not intersect and a portion where the strands intersect are mixed in the cord longitudinal direction, An eye-shaped opening is created by the intersection of the strands, and the cross section at right angles to the longitudinal direction of the cord changes sequentially, and in order to obtain a single-layer steel cord with an open contour everywhere, it is supplied to each stranding machine. This is a method in which the arrangement of the strands is periodically changed in the twisted area to replace one or more adjacent strands. The method of periodically changing the arrangement of the individual strands in the twisting area is preferably performed by passing a roll eccentric with respect to the axis while keeping the supply length of the strands substantially constant, and then forming a large number of holes. It is to pass the wiring boards arranged on the circumference.

[0007]

In the steel cord of the present invention, the portions where the strands do not intersect and the portions where the strands intersect are mixed in the longitudinal direction of the cord, and the portions where the strands do not intersect are tightened because the adjacent strands are arranged in parallel. It is in a stable and twisted state, and there is almost no gap between adjacent wires. However, a large eye-shaped gap is formed at the portion where the strands intersect with each other due to the intersection of the adjacent strands. However, in the crossed strands, the strands and strands bind to each other and move to the next parallel twisted portion, so the size and position of the gap are firmly fixed and even if external force is applied I do not. Therefore, when the steel cord is embedded in the rubber layer, the rubber smoothly enters the center of the cord through a large gap and is filled without a gap, and the surface of each strand can be reliably covered. The strands are separated from each other at the intersections of the strands, and such an intersection is repeated by changing the combination of the strands in the longitudinal direction of the cord, so that the cross section perpendicular to the longitudinal direction of the cord forms a specific shape. Instead, it has an open contour shape and is formed everywhere in the longitudinal direction of the cord. For this reason, the surface area of the cord is substantially increased, the adhesive force with the rubber is improved, and the cord is integrated with the rubber. Therefore, peeling phenomenon and rusting due to invading water are prevented, and durability is improved. Further, since the wires are restrained to each other at the intersecting portions of the wires, the buckling performance can be improved without expanding even when a compressive force acts in the cord axial direction. Further, even if the wire in the cord causes a wire breakage, the restraint action of the crossing portion prevents the wire breakage wire from being released.
The rubber layer does not penetrate, and the cord does not scatter even when the cord is cut to length before the calendering process, making it easy to handle. Moreover, in the cord of the present invention, since the individual strands have substantially the same length, the respective strands evenly bear the tensile load, and therefore the fatigue property is also improved. Further, when the frequency F of the wire intersections is set within a certain range, properties such as rubber permeability, fretting, buckling performance, and fatigue can be achieved in a well-balanced manner.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 partially shows a 1 × 4 structure single-layer steel cord to which the present invention is applied. Reference numerals 1 to 4 are strands, the diameter of which is 0.10 to 0.45 mm and the surface of which is plated with a good affinity with rubber such as brass and zinc. The strands 1, 2, 3 and 4 are twisted at once in the same twisting direction and at the same twisting pitch, as is the case with a normal collectively twisted steel cord. However, in the present invention, the twist is not intentionally disturbed by the incorporation of cross twist, rather than the regular twist which is normally formed by parallel twist like a general twisted cord. That is, as shown in FIG. 1, in the cord longitudinal direction, there are a portion a in which arbitrary strands are arranged in parallel without intersecting each other and a portion b in which arbitrary strands intersect each other. An eye-shaped opening is created, thereby forming a gap c communicating with the center of the cord axis. The parallel portions a and the intersecting portions b are alternately repeated in the cord longitudinal direction, and the positions of the strands are variously changed by the intersection. Therefore, the cord does not have a uniform cross-sectional shape at right angles to the longitudinal direction, and becomes a peculiar one that exhibits an open contour everywhere as shown in FIGS. 3 to 8 described later.

FIG. 2 is an enlarged view of a portion of the length range L of the steel cord shown in FIG. 1, showing a state in which the phases are shifted by 90 degrees in the circumferential direction and visually observed. 3 appear in this length range L.
That is, although the strands are arranged in parallel in FIG. 2 (a),
On a surface that is 90 degrees out of phase with this, for example, the wires 2 and 3 intersect, as shown in FIG. 2B, thereby forming an eye-shaped gap c having an open mouth. In addition, 90
As shown in FIG. 2 (c), for example, the strands 3 and 4 cross each other on the surfaces whose phases are shifted from each other, thereby forming a gap c. 2 (d) on the surface that is 90 degrees out of phase
Thus, for example, the gap c is formed by intersecting the wires 4 and 1. As described above, in the present invention, in a region of a certain length, the portion b where the strands intersect in the cord circumferential direction and the portion a where the strands are parallel are mixed.

FIG. 3 schematically shows a cross section obtained by cutting the cord of FIG. 1 into predetermined lengths. (a) is a parallel part a, and the strands 1, 2, 3, 4 are arranged in parallel in the clockwise direction. (b)
While the strands 1 fall to the center of the cord, the strands 4 move to the outer peripheral side and the intervals between the strands 2, 3, 4 are widened. In (c), the wire 1 again moves from the center of the cord to the outer peripheral side and cuts between the wires 2 and 3, thereby forming an intersecting portion. In (d), the wire 4 is depressed at the center of the cord. In (e), the strands 4 move to the outer peripheral side again and are arranged in the order of 1, 3, 4, 2 in the clockwise direction to form the parallel portion a.

FIG. 4 shows a steel cord having a 1 × 3 structure to which the present invention is applied. (a) shows the parallel part in which the strands 1, 2, 3 are arranged in the clockwise direction, (b) shows the parallel part in which the strand 1 is dropped into the center of the cord, and (c) shows the strand 1 in the outer circumference. On the other hand, the wire 2 moves to the side and shows the intersection where the wire 2 falls into the center of the cord so as to divide the wires 1 and 3, and (d) shows the wire 2 moving to the outer peripheral side while the wire 3 is It shows the intersection that fell into the center of the cord so as to divide lines 1 and 2. FIG. 5 shows a steel cord having a 1 × 5 structure to which the present invention is applied. (a) shows the parallel part where the strands 1, 2, 3, 4, 5 are arranged in a clockwise direction, and (b) shows the state where the strand 1 has fallen to the center of the cord,
(c) shows the intersection where the wire 1 has moved to the outer circumference side and the wire 2 has fallen to the center of the cord. (d) shows the wire 2 moved to the outer circumference and the wire 3 has been crossed. The crossing portion is shown centered on the center, and (e) shows the crossing portion where the wire 3 has moved to the outer peripheral side and the wire 4 has fallen to the center of the cord.

FIG. 6 shows a steel cord having a 1 × 7 structure to which the present invention is applied. (a) shows strands 1, 2, 3, 4,
5, 6 and 7 are parallel to each other, (b) shows the intersection where the wire 1 at the center moves to the outer circumference side and the wire 7 is replaced and moves to the center, (c) Is the wire 7 is the wire 3
4 shows an intersection where the wire 5 moves to the outer periphery so as to cut in between 4 and 4, and the wire 5 is moving to the center, and (d) shows an intersection where the wire 5 moves to the center. FIG. 7 shows one twist pitch of a steel cord of 1 × 6 structure to which the present invention is applied divided into 14 equal parts. In FIG. 7A, the wire 1 is located in the central portion. 1 is a wire, adjacent to 3, 4 (f) or
As shown in (h), the wires gradually move to the outer diameter side, and as shown in (i) to (m), the wire 4 moves to the center of the cord. The wire 2 is rotating in the counterclockwise direction adjacent to the wire 1, but when the wire 1 moves to the outer diameter side, it is cracked as shown in (f) to (n). Also, although the wire 4 is initially located on the outer diameter side, it moves to the center as shown in (i) to (n), and the wire 5
Are adjacent to the strands 4 and 6 as shown in (a) to (g), but are separated from the strands 6 as the strands 4 fall into the central portion. As a result, the three strands are interchanged as shown in (a) and (n), and the cross section at right angles to the longitudinal direction of the cord is not a specific shape but has an open contour that changes everywhere. FIG. 8 shows one twist pitch of a steel cord having a 1 × 9 structure to which the present invention is applied.
It is shown divided into 5 equal parts. In (a), the wire 1 is located at the center, but the wire 1 cuts between the wires 2 and 9 as in (b) to (i). And so on, with wire 7 being wire 1
While moving to the center side while adjoining, the wire 1 moved to the outer circumference in (j), and the wire 8 that was on the outer circumference side until then (k) to (q)
, And then the wire 8 interrupts again between the wires 3 and 5, and the wire 1 adjacent to the wire 8 as in (s) to (w) is coded again. It moved to the center, and the wire 2 started to fall like (w) to (y). (a) and (y)
As is clear from the comparison, the strands 1 to 9 are moved counterclockwise and are completely exchanged between the twist pitches, and the gaps c are everywhere.
Is formed.

In any case, in the steel cord of the present invention, each strand moves in any order between the center side and the outer periphery of the cord and on the outer diameter side, or adjacent strands on the outer diameter side are exchanged. The crossing cycle is repeated, and a crossing portion is formed in the process of the movement of the strands, and the strands of the other party forming the parallel twist change depending on the strand interruption position at the time of the movement. When the strands intersect, the strands on the outer peripheral side may intersect with each other, or the strands on the outer diameter side and the center side may intersect with each other. In addition, when the number of strands is 5 or more, the strands of two or more parallel strands may intersect with one or more other strands. Therefore, the position of the wire when it is moved to the outer peripheral side is not limited to the position shown in FIGS. However, in any case, unlike ordinary single-layer steel cords, the twists are tightly twisted, but as is clear from FIGS. 4 to 8, the mouth opening is created by the intersection of the wires. In the example of FIG. 8 in which nine strands are used, the open contour shape portion having a gap leading to the center of the cord is not one in which all the strands are adjacent shapes (closed contour shape).
There are also 19 places formed in the twist pitch.

The present invention is applied to a collectively twisted steel cord having three or more strands. In addition to the above-mentioned example, 1
X8, 1x9, 1x10, 1x11, 1x12, 1x1
3, 1 × 15, 1 × 17, etc. are included. However, if the number of strands exceeds 19, there is a possibility of a multilayer structure in which an open contour shape portion is not formed, and in that case, the amount of rubber intruding into the central portion of the cord decreases, which is not appropriate. In the present invention, the frequency F at which the strands cross each other at a certain cord length L (mm) as described above is changed in relation to the number of strands n (≦ 3) and the cord twist pitch P (mm). The following formula should be satisfied. 1) When the number of strands n is 3 ≦ n ≦ 6 0.5 ≦ (F × P) /L≦4.0 2) When the number of strands n is 7 ≦ n ≦ 19 0.5 ≦ (F × When P) /L≦15.0 (F × P) / L is less than 0.5, the number of strands crossing is small and the number of eye-shaped openings is small, so the amount of rubber permeation into the center of the cord is reduced. However, it is not suitable because the binding force between the wires is insufficient. However, when (F × P) / L is less than 6 strands, it exceeds 4.0, and when the number of strands is 7 or more, 19
If the number is more than 15.0 in the case of less than or equal to this number, the rubber permeability and the restraining force are good, but the length of the strands twisted into the cord is unbalanced and fatigue resistance is reduced. This is also unsuitable as it tends to decrease and fretting wear tends to occur. Within the specified range, properties such as rubber permeability, binding force, fatigue resistance and fretting wear resistance can be achieved in a well-balanced manner. A more preferable range is 0.5 ≦ (F × P) / L ≦ in the case of 1)
2.0, and in the case of 2) 1.0 ≦ (F × P) / L ≦ 1
It is 0.0. The present invention is basically based on the fact that the wires constituting the cord have the same thickness, but the thickness may be different depending on the case.

Next, a method for manufacturing a steel cord according to the present invention will be described. The steel cord according to the present invention can be manufactured by either a buncher twisting machine or a tubular twisting machine, but when using any twisting machine, the arrangement of the individual strands supplied to the twisting machine Is periodically changed in the twisting area. FIG. 9 shows an example in which a double twist type buncher type twisting machine is used. Reference numeral 15 is a main body, which has a cradle 152 and hollow shafts 151 and 151 ′ driven and rotated by a prime mover 150, and is coaxial with the cradle 152. Above the bow 153, which rotates integrally with the hollow shafts 151, 151 '.
A winding bobbin 156, a capstan 155 is provided upstream of the winding bobbin 156, and a supertwisting machine 154 is provided upstream of the winding bobbin 156. A voice 16 that collects a plurality of three or more strands is provided upstream of the hollow shaft 151 on the inlet side, and the strand length including the voice 16 makes the supply length of the strands substantially constant. A control device 17 is provided for periodically changing the wire array while maintaining the same. As shown in FIG. 11, the control device 17 is composed of a wiring board 18 having a large number of holes 175 through which the wires are inserted on the same circumference, and a group of rolls upstream thereof. A plurality of supply bobbins (not shown) are provided, and each of the supply bobbins is led out so that the supply length is kept substantially constant. The control device 17 has an eccentric roll 17a, and the eccentric roll 17a is rotatably supported by a shaft at a predetermined level higher than that of the wiring board 18. Before and after this eccentric roll 17a, free rolls 17b and 17b 'are arranged at a height level almost equal to that of the wiring board 18, and the eccentric roll 17a is provided downstream of the upstream free roll 17b'.
Is provided with a guide roll 17c having a slightly different height level and a guide roll 17c 'having a level almost equal to that of the free roll 17b. Freeroll 17
b'and 17b are provided with a plurality of rolls each having a short body length on a shaft so as to be individually rotatable through bearings, and grooves are provided to guide the strands to each roll. On the other hand, each of the guide rolls 17c and 17c 'is composed of a single roll, and is provided with a large number of grooves for guiding the strands in parallel. After being wound, it is guided to the guide roll 17b ', wound once, and then guided to the free roll 17b.

FIG. 10 shows two examples of the eccentric roll 17a. FIG. 9 (a) shows a body 1 having a predetermined diameter D.
12 grooves 173 of the same depth are formed at 72 at equal intervals,
In addition, the body portion 172 is eccentrically cranked with respect to the center line CL for each predetermined length, and the six eccentric roll portions 170a, 1
70b, 170c, 170d, 170e, 170f are formed. Similarly, FIG. 9B shows that four eccentric roll portions 170a, 170b, 170c, 170d are formed. When the number of strands is more than 12, the number of grooves is naturally increased, and the number of eccentric roll parts is arbitrary as long as it is two or more. For example, three eccentric roll parts, 5
It may have one eccentric roll portion, or one having seven or eight eccentric roll portions. It is necessary that the holes 175 of the wiring board 17d be arranged at equal intervals and on the same circumference in a number equal to or larger than the number of strands of the cord to be manufactured. If the holes 175 are arranged on two or more concentric circles, the positions of the strands are fixed, and a unique code as intended by the present invention cannot be obtained. The wiring board 17d may have different numbers of holes depending on the number of strands of the cord to be manufactured, or the number of holes corresponding to the maximum number of strands of the cord to be manufactured may be used. The wire may be inserted by appropriately selecting the hole.

In manufacturing the steel cord of the present invention, n wires (however ≧ 3) are fed from each supply bobbin in the same manner as in the normal bunched cord manufacturing, and these wires are the wiring board 17d. From the guide roll 157 to the bow 15 through the hollow shaft 151.
3 through the other guide roll 158 to the hollow shaft 15
1'to the overtwisting machine 154 and the capstan 155
It is guided to the winding bobbin 156 via the, and in this state, the hollow shafts 151 and 151 ′ are driven to rotate the bow 153. The strands are continuously sent to the voice 16 to be bundled, enter the hollow shaft 151 in that state, and in the process of reaching the guide roll 157, the first twist is put in and the guide roll 15
In the process from 8 to the hollow shaft 151 ′, the second twist is put into a steel cord, and while passing through the overtwisting machine 154, the twist is adjusted and wound on the winding bobbin 156.

At this time, the strands of wire pass through the controller 17 in advance and are wound around the guide rolls 17c 'and 17c one or more times respectively, and then pass through the eccentric roll 17a and the free roll 1 respectively.
It is led from 7b to each hole of the wiring board 18. In the case where the number of strands is 12, for example, the strands from the free roll 17b to the grooves 1 of the eccentric roll 17a illustrated in FIGS. 10 (a) and 10 (b) are used.
73 are arranged in parallel with each other. When the number of strands is smaller than this, eccentric roll portions are appropriately selected and arranged in arbitrary numbers. For example, when the number of strands is 3, the eccentric roll portions 170a to 170c or 170a to 170f
It is sufficient to select one of the above and arrange one in each groove of different eccentric roll portions. When the number of strands is 4, select one of the eccentric rolls 170a to 170f and place one in each groove of the different eccentric rolls, or use 3 eccentric rolls for a 2: 1 ratio. : 1,1: 2:
It may be arranged as 1, 1: 1: 2, or the like. The same applies to the case of five or more wires, and each wire may be arranged one by one on different eccentric rolls, or the wires may be divided into groups and arranged on different eccentric rolls by an arbitrary number. This is most true when the number of eccentric rolls is less than the number of strands. For example, in the case of 9 strands and when FIG. 9 (a) is used as an eccentric roll, 2 strands are applied to the 3 eccentric rolls, and 1 to the other 3 eccentric rolls. You can just apply the wire. When Fig. 9 (b) is used as an eccentric roll, the number of wires hanging on any of the eccentric rolls is set to three, for example, it is arranged in two: 2: 2: 3 or It is optional to set the number of strands of the eccentric roll portion to be 1, for example, 1: 2: 3: 3. Then, the strands downstream of the eccentric roll 17a are guided to the wiring board 17d via the free roll 17b, and the holes 175 on the same circumference are arbitrarily selected and inserted. This wiring passes clockwise or counterclockwise such that the wire located at the end of the eccentric roll 17a is passed through an arbitrary hole at the north pole position and the next wire is passed from the end to the hole next to the north pole position. It may be permuted, or a wire located at the end of the eccentric roll 17a is passed through a hole at an arbitrary position, for example, the North Pole, and the next wire from the end is passed through a hole at the South Pole in a diagonal or diagonal relationship. You may pass. It is possible to freely adjust the exchange of the strands depending on such a wiring condition and how to hang it on the eccentric roll 17b.

When the strands are laid on the eccentric roll 17a and the twisting process is performed, a crank motion is generated because the eccentric roll 17a is divided into a plurality of eccentric roll parts, and the eccentric roll part is hung on the eccentric roll part. The tension of the existing wire is changed in a predetermined order and periodically. For example, in FIG.
In the state of (a), the tension applied to the wire hanging in the groove of the eccentric roll portion 170b is the most relaxed.
The tension is loosened in the order of 0d-170e-170f-170c-170a, and in the state of Fig. 10 (b), the tension of the wire hanging in the groove of the eccentric roll portion 170b is the most relaxed, and from this state, the eccentric roll portion 170c-170d-1
The cycle of releasing the tension is repeated in the order of 70a. These strands are passed through the holes 175 of the wiring board 17d in an arbitrary arrangement, guided to the voice 16 and collected, and then guided to the main body 15 and twisted together. In this way, the one or more strands whose tension is relaxed are twisted by being placed instantaneously on the center side of the strand bundle from the state where they were aligned in parallel so that they were in contact with the adjacent strands. Subsequently, the tension is returned to the original tension and the tension of the next strand is relaxed to move toward the center of the bundle of strands, whereby the strands are moved to the outer peripheral side and twisted with the adjacent strands. Further, the wires on the outer peripheral side are also twisted while moving so that adjacent wires are exchanged. The local crossover twist is repeated in a predetermined sequence and periodically according to the movement loci of the outer circumference side-center side-outer circumference side, center side-outer circumference side-center side, and outer circumference side of each of these strands. The local cross twist disturbs the parallel twist to form a gap.

Next, specific examples of the present invention will be shown.

Example 1 Using the twisting machine shown in FIG. 8, a steel cord of the present invention having a 1 × 9 structure was manufactured. The wire used has a diameter of 0.22 mm, the twist pitch P is 12 mm, the twist direction is S, and the eccentric roll has a groove circumference of 94.2 mm and an eccentricity of 2 mm.
0 (a) is used, and the strand is eccentric roll part 170a: 170b: 170c: 17
0d: 170e: 170f = 2 lines: 1 line: 2 lines: 1 line: 2
Book: Use in a relationship of 1 and use 9 holes as a wiring board arranged at equal intervals and on the same circumference, and pass the free-rolled wires through the holes of the wiring board in the clockwise direction. , Created a bunched code. As a result, the cord diameter is 0.828m
The steel cord having a cross-section frequency F of 41 times at m and a length of 120 mm and a cross section perpendicular to the cord longitudinal direction was obtained as shown in FIG. The properties of this steel cord were measured. As a result, cutting load: 93.6 kgf, rubber adhesion (by peeling method): 8 kgf / 90%, rubber permeability (permeating in the longitudinal direction inside the cord by applying air pressure of 5 atm to the end of the cord embedded in rubber) According to the method of measuring the amount of air in cc / min): 0
At cc / min, 0 → 5.0kgf elongation: 0.131%, 0 → 2.0kgf elongation:
Fatigue resistance of 0.072% (according to the three-roll method): 20787 times was obtained, and the buckling test was also good when a load was applied from the axial direction and visually observed. Also, the groove circumference as an eccentric roll
Using Fig. 10 (b) with 94.2mm and eccentricity of 2mm, hang the wires in the relationship of eccentric rolls 170a: 170b: 170c: 170d = 3 rolls: 2 rolls: 2 rolls: 2 rolls. A bunched code was created by using the same sequence as described above. As a result, the cord diameter is 0.856 mm,
A steel cord with a wire crossing frequency F of 35 times at a length of 120 mm was obtained. This steel cord has a cutting load of 93.6kg.
f, rubber adhesion (by peel method): 9kgf / 90%, rubber permeability: 0cc / min, 0 → 5.0kgf elongation: 0.128%, 0 → 2.0kgf elongation: 0.069%, fatigue property: 20882 times Was obtained, and the buckling test, which was visually observed by applying a load from the axial direction, was also good. From these results, the cord of the present invention has good rubber permeability even though it is tightly twisted, and the crossing frequency is appropriate, so that the properties such as elongation, fatigue resistance, and buckling resistance are also good. I understand.

[0021]

As described above, according to the first to fifth aspects of the present invention, the rubber penetration into the center of the cord and the adhesion to the rubber are good, and the fatigue resistance is good, and the cord is in the axial direction. It has an excellent effect of being able to obtain a steel cord for rubber reinforcement having high practicality, which is strong against the compression pressure of (good buckling performance). According to claims 9 and 10, the excellent effect that the steel cord having the characteristics of claims 1 to 5 can be manufactured economically and efficiently in one step is obtained.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a steel cord according to the present invention.

FIG. 2 is a side view showing a certain length range of a steel cord according to the present invention with a phase shifted by 90 degrees.

FIG. 3 is a cross-sectional view of each part of the cord shown in FIG.

FIG. 4 is a sectional view showing another example of the steel cord according to the present invention.

FIG. 5 is a cross-sectional view showing another example of the steel cord according to the present invention.

FIG. 6 is a cross-sectional view showing another example of the steel cord according to the present invention.

FIG. 7 is a cross-sectional view showing another example of the steel cord according to the present invention.

FIG. 8 is a cross-sectional view showing another example of the steel cord according to the present invention.

FIG. 9 is an explanatory view showing an example of a method for manufacturing a steel cord according to the present invention.

FIG. 10 is an explanatory view illustrating an eccentric roll used in the present invention.

FIG. 11 is a front view illustrating a wiring board used in the present invention.

[Explanation of symbols]

 1,2,3,4,5,6,7,8,9 Elementary wire a Parallel part b Crossing part c Gap 17 Control device 17a Eccentric roll 17d Wiring board 170a-170n Eccentric roll part 175 hole

Claims (10)

[Claims] 1. In a steel cord having a 1 × n structure in which three or more strands are twisted at the same twisting direction and at the same twist pitch, a portion where the strands do not intersect and a portion where the strands intersect are mixed in the longitudinal direction of the cord. , A steel cord for rubber reinforcement characterized in that an eye-shaped opening is created by the intersection of the strands, and the cross section at right angles to the longitudinal direction of the cord changes sequentially and has an open contour everywhere. 2. The number of strands is 3 or more and 6 or less, and each strand enters from the outer diameter side of the cord to the center side of the cord and moves again to the outer diameter side of the cord to replace adjacent strands with each other. And the strand crossing frequency F is 0.5 ≦ (F × P) in the relation between the cord length L and the twist pitch P.
The steel cord for rubber reinforcement according to claim 1, wherein /L≤4.0. 3. The strand crossing frequency F is 0.5 ≦ (F × P) / L ≦
The steel cord for rubber reinforcement according to claim 2, which is in a range of 2.0. 4. The number of strands is 7 or more and 19 or less,
Each strand enters from the outside diameter side of the cord to the center side of the cord and moves again to the outside diameter side of the cord, or moves from the center side of the cord to the outside diameter side of the cord and enters again to the center side of the cord, or adjacent to the outside diameter side. The strands intersect each other by exchanging the strands, and the strand crossing frequency F is 0.5 ≦ (F × P) / L ≦ 15 in the relation between the length L and the twist pitch P.
The steel cord for rubber reinforcement according to claim 1, which is in a range of 0. 5. The strand crossing frequency F is 1.0 ≦ (F × P) / L ≦
The steel cord for rubber reinforcement according to claim 4, which is in a range of 10.0. 6. The crossing of the strands includes both crossing of the cord outer diameter side strands and crossing of the cord outer diameter side strands and the cord center side strands. Steel cord for rubber reinforcement described in. 7. The method according to claim 1, wherein the intersection of the strands includes a case where two or more adjacent strands are parallel to each other and intersect one or more other strands. Steel cord for rubber reinforcement as described. 8. The rubber-reinforcing steel cord according to claim 1, wherein the number of strands is 3 or more and 19 or less, and the strand diameter is 0.1 to 0.45 mm. 9. A 1 × n structure in which three or more strands are twisted at the same twist direction and at the same twist pitch, and a portion where the strands do not intersect and a portion where the strands intersect are mixed in the cord longitudinal direction, Each element supplied to the stranding machine is used to obtain a single-layer steel cord that has an eye-shaped opening created by the crossing of the strands and the cross section at right angles to the longitudinal direction of the cord changes sequentially and has an open contour everywhere. A method for manufacturing a steel cord for rubber reinforcement, which comprises periodically changing the arrangement of wires in the twisting area to replace one or more adjacent wires. 10. A periodical change in the twisting area of the array of strands passes through a roll eccentric to the axis while keeping the feed length of the strands substantially constant, and then multiple holes are formed in the same circle. The method for manufacturing a rubber-reinforcing steel cord according to claim 9, which is carried out by passing a wiring board arranged on the circumference.