JPH07309103A - Radial tire - Google Patents

Abstract

PURPOSE:To prevent the separation of the rubber by mixing the part where the strands of the steel cord are not crossed with each other with the part where the strands are crossed with each other to form the opening of eye-shape through the crossing of the strands, and consecutively changing the square section in the longitudinal direction of the cord and providing open contours at various parts to improve the impregnation and adhesiveness of the rubber. CONSTITUTION:Three or more strands 1-4 constituting the belt are stranded with the same stranding direction and pitch to form a steel cord 10. The part (a) where the arbitrary strands are arranged in parallel without being crossed with each other and the part (b) where the arbitrary strands are crossed with each other are provided in the longitudinal direction of the cord, an opening of the eye shape is formed at the crossed part (b) to form a clearance (c) communicating with the axial center of the cord, and the parts (a) and (b) are repeatedly and alternately provided in the longitudinal direction to form the open contour. The impregnation of the rubber and the adhesivity to the rubber are excellent to provide the excellent set of strands, and the separation from the rubber due to the shear strain at thc edge of the belt can be prevented because the steel cord which is highly resistant against the fatigue and the compression in the axial direction of the cord.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a pneumatic radial tire reinforced with a steel cord.

[0002]

2. Description of the Related Art As is well known, radial tires are provided with a plurality of reinforcing portions called belt layers provided between a tread and a carcass so as to tighten the carcass in the radial direction. A steel cord formed by twisting a plurality of strands (filaments) is used for such a belt layer. There are various types of steel cords, but so-called 1 × n, in which a plurality of strands are twisted in the same twisting direction and the same twisting pitch, especially the number of strands is 6
Bunched cords below this book tend to be used more often because of their cost advantages. By the way, the strain generated in the tire is a combination of static strain generated by applying internal pressure and dynamic strain generated in the ground contact portion when the tire is moving. Looking at the belt layer, the static strain of the steel cord is the largest at the center of the crown, and the strain is zero at the shoulder because it is the free end. Correspondingly, the shear strain is the largest at the end of the cord. . That is, the interlayer shear strain is the largest at the belt edge, and the separation phenomenon between the cord and the rubber is likely to occur. Further, the dynamic strain is mainly bending strain, and this bending strain causes expansion and compression strain of the cord and the rubber, and also generates concentrated strain at the belt edge and the like. Then, the tire is distorted by the cornering force and the driving braking force, and the distortion is particularly affected by the lateral force due to cornering, and the belt is bent in the plane by the lateral force. No compressive strain
(Compression force in the code axis direction) is added.

In order to deal with such a situation, the first
In addition, the steel cord must be a composite that is firmly integrated with the rubber. Secondly, the strand assembly must be cohesive and have good mechanical properties such as high rigidity and resistance to a niverd cage when compressed. As for the former, if the adhesion state between the steel cord and the rubber is not perfect, the above-mentioned shear strain and bending strain easily cause the peeling phenomenon between the steel cord and the rubber, and intrusion from the outside through scratches on the tread. The generated moisture causes rust on the steel cord, which significantly reduces the cutting load of the steel cord and accelerates separation. In order to deal with this, it is necessary to allow the rubber to permeate to the center of the steel cord and to make the rubber adhere well to the outer circumference of the wire. But,
A normal bunched cord has a compact form in which the individual wires are arranged in parallel without intersecting each other unless special preforming is performed. For this reason, rubber permeability 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.

Regarding the latter, when the strand assembly has poor integrity and poor mechanical properties, shear strain,
Repeated stretching strains and compression strains cause the cord ends to come apart, and fatigue causes bending, resulting in insufficient function as a reinforcing material. However, this function is difficult to be compatible with the former function (rubber permeability and adhesive force), and as described above, making the twist of the steel cord loose so as to make the gap between the strands large makes The strands are grouped together to diminish the property of acting as a strength member. That is, although the above-mentioned gap forming technology is theoretically aside, in the steel cords actually applied, there are many cases where a certain wire is in contact with another wire at only one point, and the twisting is unstable. However, there is a problem in that the gap between the individual strands is not constant, and a state in which the strands are biased to one side occurs and uniform rubber permeability decreases. In addition, when a compressive force acts in the axial direction of the cord, the mutual restraining force of the wires cannot be expected, so it is easy for multiple wires to open in four or eight directions, a so-called birdcage-like shape, which causes buckling and breakage. The problem is that it becomes easier. Further, since the binding force between the wires is weak, there is a risk that the wire-breaking end breaks through the rubber layer and sticks out when the wires are broken.

Incidentally, Japanese Patent Publication No. 4-13473 discloses that
A bunched code of a multi-layer steel cord such as a two-layer (3 + 9 structure) or a three-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, this prior art is not suitable for a belt layer because the cord diameter becomes large, and although it is possible to increase the pullout resistance of the central layer, rubber permeability is not taken into consideration, and the cord longitudinal direction is not considered. It is a so-called closed contour type in which the cross section perpendicular to is always specified as a polygonal shape, and since the cord does not open outward, rubber permeability deteriorates. Further, since the core layer has a multi-layered structure, the lengths of the strands of the central layer and the outer layer are considerably different. Therefore, when a tensile load is applied, a large load is applied to the strands of the central layer, and the fatigue property is deteriorated. Therefore, it is practically difficult to satisfy the above two characteristics.

The present invention was devised to solve the above-mentioned problems. The purpose of the present invention is to allow the rubber to penetrate well into the center of the cord and to have good adhesion to the rubber. It is to provide a radial tire capable of accurately preventing the above, yet having good mechanical properties as a wire aggregate and having good mechanical properties, and being able to withstand dynamic and static strains well. .

[0007]

In order to achieve the above object, the present invention is at least partially reinforced by a 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. In the radial tire described above, the steel cord has a portion where the strands do not intersect and a portion where the strands intersect in the longitudinal direction of the cord, and an eye-shaped opening is created by the intersection of the strands, which is perpendicular to the longitudinal direction of the cord. The cross-section of is changed sequentially and has an open contour everywhere. Suitably the steel cord is used in the belt layer. In this case, the number of strands is 3 or more and 7 or less, and the strand crossing frequency F is 0.5 ≦ (F × P) / L ≦ 4 in the relationship between the cord length L and the twist pitch P. 0
The range of 0.5 ≦ (F × P) /L≦2.0 is more preferable. 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 are a large number of intersecting portions at a predetermined frequency such that they move to the outer diameter side and move again to the center side of the cord, or the adjacent outer diameter wire is exchanged. 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. The other one
This includes the case where it intersects with more than one strand. The steel cord is preferably made by periodically changing the arrangement of the individual strands supplied to the stranding machine in the twisting area, and replacing one or more adjacent strands. The method of periodically changing the arrangement of each wire in the twisting area is preferably such that a plurality of holes are formed in the same circle through a roll eccentric to the axis while keeping the supply length of the wire substantially constant. It is to pass the wiring board arranged on the circumference.

[0008]

In the present invention, in the steel cord, 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 adjacent strands are arranged in parallel in the portions where the strands do not intersect. Therefore, it is tight and stable, 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, the separation phenomenon with rubber and rusting due to invading water are prevented, and when applied to the belt layer, the durability against the belt edge shearing strain generated at the time of cornering can be greatly improved. Despite having the above characteristics, the strands are constrained to each other at the intersecting portions of the strands, so they are well organized as a strand aggregate, and when compressive force acts in the cord axial direction. The buckling performance can be improved without expanding. Further, even if the wires in the cord are broken, the restraining action of the intersecting portion prevents the broken wires from being released, so that the cord does not come apart and the rubber layer does not penetrate. Moreover, since the individual strands have substantially the same length, the individual strands evenly bear the tensile load, and therefore the fatigue property is also improved. In particular, when the wire crossing frequency F is set within a certain range, properties such as rubber permeability, fretting, buckling performance, and fatigue can be achieved in a well-balanced manner. Therefore, according to the present invention, it is possible to improve durability against strain due to internal pressure filling, strain at the time of load due to running, and extension / compression strain due to lateral force.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a radial tire to which the present invention is applied. 11 is a carcass, 12 is a tread, 13a, 13
Reference numerals b, 13c and 13d denote a plurality of (four in this example) belts arranged between the carcass 11 and the tread 12. The belts 13a, 13b, 13c, 13d are made by topping rubber from both sides of the steel cords 10 arranged in parallel to form a rubber layer 14 and vulcanizing it.
The rubber may be natural rubber or synthetic rubber, but in terms of separation and cord durability, 50% modulus is 10
It is preferably ˜40 kg / cm ² . The characteristic of the present invention resides in the steel cord 10. FIG. 3 shows 1 × in the present invention.
The single-layer steel cord 10 having four structures is partially shown. Nos. 1 to 4 are wires and have a diameter of 0.10 to 0.45 mm
The surface is plated with brass and zinc, which has a good affinity with rubber. 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. 3, 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 has a peculiar shape that exhibits an open contour everywhere as shown in FIGS.

FIG. 4 is an enlarged view of a portion of the length range L of the steel cord shown in FIG. 3, showing a state in which the phases are shifted by 90 degrees in the circumferential direction and visually observed, and an intersecting portion b where a gap c is formed. 3 appear in this length range L.
That is, in FIG. 4 (a), the strands are arranged substantially parallel to each other, but on the surface 90 ° out of phase with this, for example, strands 2 and 3 intersect as shown in FIG. 4 (b). As a result, a gap c having an open mouth is formed in an eye shape. Further, for example, as shown in FIG. 4 (c), the strands 3 and 4 cross each other on the surface 90 ° out of phase with each other, thereby forming a gap c. Furthermore, in the plane that is 90 degrees out of phase from now on,
As shown in (d), a gap c is formed, for example, by intersecting the wires 4 and 1. As described above, in the present invention, in a region of a certain length, a portion b where the strands intersect and a portion a where the strands are parallel are mixed even in the cord circumferential direction.

FIG. 5 schematically shows a cross section of the cord of FIG. 1 cut into a predetermined length. (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. 6 shows a steel cord 10 of 1 × 3 structure according to the present invention. (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. 7 shows the present invention 1
A steel cord 10 having a × 5 structure is shown. (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. In each of the steel cord 10 and the other, as in the case of FIG. 3 described above, in the cord longitudinal direction, a portion a in which the arbitrary strands are arranged in parallel without intersecting each other and the arbitrary strands are mutually Has a portion b intersecting with each other, and an eye-shaped opening is created in the intersecting portion b, thereby forming a gap c communicating with the center of the cord axis, and the parallel portion a and the intersecting portion b are formed.
Are alternately repeated in the longitudinal direction of the cord, and the position of the strand changes variously due to the intersection. Further, as in FIG. 4, in a region of a certain length, a portion b where the strands intersect and a portion a where the strands are parallel are mixed in the cord circumferential direction, and at a certain phase in the circumferential direction, A gap c with an open mouth is formed in the shape of an eye by intersecting the three to three strands, and on a surface with a further phase shift, two or more strands that are different from or part of the strands are common. The strands intersect, thereby forming a gap c. Further, even on a surface whose phase is shifted from this, a gap c is formed by intersecting two or more strands which are different from or partially common to the strand of the phase.

FIG. 8 shows a steel cord 10 having a 1 × 6 structure according to the present invention, in which one twist pitch is divided into 14 equal parts. In FIG. 8A, the wire 1 is located at the center. The strand 1 is moved to the outer diameter side sequentially as shown in (f) to (h) while being adjacent to the strands 3, 4 and the strand 4 as shown in (i) to (m).
Is moving to the center of the code. 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, (i)
Or (n) moves to the center, and the wire 5 is adjacent to the wires 4 and 6 as shown in (a) to (g), but the wire 4 falls to the center. Accordingly, it is separated from the wire 6. 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. 9 shows a steel cord of 1 × 7 structure according to the present invention. (A) shows the strands 1, 2, 3, 4, 5,
6 and 7 show parallel parts, (b) shows an intersecting part in which the wire 1 at the center moves to the outer peripheral side and the wire 7 is replaced and moves to the center, (c) shows Wire 7 is wires 3 and 4
The wire 5 moves to the outer circumference so as to be interrupted, and the wire 5 is moving to the center, and (d) shows the wire 5 moving to the center. The steel cords of FIGS. 3 to 9 are the most suitable cord structures for the belts 13a, 13b, 13c and 13d. However, FIGS.
Steel cords are not necessarily limited to all belts. For example, farthest from the carcass
A cord having a large cutting elongation may be used for the belt 13d (close to the tread). FIG. 10 shows one twist pitch of a steel cord of 1 × 9 structure divided into 25 equal parts. In FIG. 10A, the wire 1 is located in the central portion.
Moves so as to interrupt between the wires 2 and 9 as in (b) to (i), and the wire 7 moves to the center side while adjoining the wire 1, and in (j), The wire 1 moves to the outer circumference, and the wire 8 that was on the outer circumference side until then falls to the center side as shown in (k) to (q), and then the wire 8 is again between the wires 3 and 5. Interrupt, strand 1 that was adjacent to strand 8 as in (s) to (w) has moved to the center of the cord again, and strand 2 is beginning to fall as in (w) to (y) . As is clear from comparison between (a) and (y), the strands 1 to 9 are moved counterclockwise and completely interchanged between one twist pitch to form gaps c everywhere.
This cord is suitable for carcass reinforcement.

In any case, the steel cord 1 of the present invention
0 means that each strand moves in an arbitrary order between the cord center side and the outer circumference side and on the outer diameter side, or the adjacent strands on the outer diameter side are exchanged, and a repeating cycle repeats.
Intersections are formed in the process of movement of the strands, and the strands of the other party forming the parallel twist change depending on the strand interruption position during 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 when the wire is moved to the outer peripheral side is not limited to the position shown in FIGS. 6 to 10. However, in any case, unlike ordinary single-layer steel cords, although the wires are tightly twisted, as is clear from FIGS. 6 to 10, the mouth opening is created by the crossing of the wires. The feature is that, even in the example of FIG. 10 using nine strands, all strands are adjacent (closed contour shape)
There are also 19 open contour-shaped portions having a gap leading to the center of the cord within one twist pitch.

In the present invention, the frequency F at which the wires cross each other at a certain cord length L (mm) as described above is replaced by
The relationship between the number of strands n (≦ 3) and the cord twist pitch P (mm) should satisfy the following equation. 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 ≦ 14 0.5 ≦ (F × When P) /L≦15.0 (F × P) / L is less than 0.5, the number of crossing of the strands is small,
Since the number of eye-shaped openings is reduced, the amount of rubber penetrating into the center of the cord is reduced, and the binding force between the wires is insufficient, which is not suitable. However, when (F × P) / L is less than 7 strands, it exceeds 4.0, and when the number of strands is 8 or more, 1
If the number is more than 15.0 when the number is 4 or less, rubber penetration and binding force are good, but the length of the strands twisted into the cord is unbalanced and fatigue resistance Is also unsuitable because it tends to decrease and fretting wear easily occurs. Within the specified range,
Properties such as rubber permeability, binding force, fatigue resistance, and fretting wear resistance can be realized 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. For the carcass, in addition to the above examples, 1 × 8, 1 × 9, 1 × 10, 1 × 11, 1
It includes x12, 1x13, 1x14 and the like. However, when the number of strands exceeds 15, there is a possibility that a multilayer structure in which the open contour shape portion is not formed is formed, and in that case, the amount of rubber intruding into the central portion of the cord is reduced, which is not appropriate. The steel cord for reinforcing the carcass using the present invention is made by twisting 8 or more and 14 or less strands of wire together, and each strand enters from the cord outer diameter side to the cord center side and again to the cord outer diameter side. The wires intersect with each other by moving, moving from the cord center side to the cord outer diameter side and entering the cord center side again, or by exchanging adjacent outer diameter side strands, the strands intersect each other. The frequency F is 0.5 ≦ (F × P) / L ≦ 1 in the relation between the length L and the twist pitch P.
5.0 range, preferably 1.0 ≦ (F × P) / L ≦ 10.
A configuration in the range of 0 is suitable.

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. 11 shows an example using a double twist type buncher type twisting wire machine, 15 is a main body,
A cradle 152 and hollow shafts 151 and 151 ′ that are driven and rotated by a prime mover 150, and a bow 15 that rotates integrally with the hollow shafts 151 and 151 ′ coaxially with the cradle 152.
3, 153 are attached, and the cradle 152 has a take-up bobbin 156 and a capstan 155 upstream thereof.
Is provided, and the overtwisting machine 154 is arranged upstream of this. 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. 12, the control device 17 is composed of a wiring board 17d having a large number of holes 175 through which the wires are inserted on the same circumference, and a roll group upstream of the wiring board 17d. 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,
The guide roll 1 having a slight difference in height level from the eccentric roll 17a is provided downstream of the upstream free roll 17b '.
7c and a guide roll 17c 'having substantially the same level as the free roll 17b are provided. Each of the free rolls 17b 'and 17b has a plurality of rolls each having a short body length attached to its shafts via bearings so as to be individually rotatable, and each roll has a groove for guiding a wire. 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 wires in parallel.
After being wound around c'once, it is guided to the guide roll 17b 'and wound once, and then guided to the free roll 17b.

FIG. 12 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. 12B 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 portions is arbitrary as long as it is two or more. For example, three eccentric roll portions,
It may be one having five eccentric rolls, seven or eight eccentric rolls, or the like. 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 wiring boards 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 15
It is guided to the winding bobbin 156 via 5. 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, and then enter the hollow shaft 151 in this state, and then the guide roll 1
During the process of reaching 57, the first twist is applied, and during the process of reaching the hollow shaft 151 ′ from the guide roll 158, the second twist is applied to form a steel cord, which passes through the overtwisting machine 154. The twist is adjusted and wound on the winding bobbin 156.

At this time, the wire passes through the control device 17 in advance and is wound around the guide rolls 17c 'and 17c one or more times respectively, and then passes through the eccentric roll 17a and then the free roll 1a.
7b is led to each hole of the wiring board 17d. When the number of strands is 12, for example, the strands are free rolls 17b.
10 (a) and 10 (b), they are arranged in parallel with the respective grooves 173 of the eccentric roll 17a. 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 17
Any one of 0f may be selected and one groove may be arranged in each groove of different eccentric roll portions. If the number of strands is 4,
Select the eccentric rolls 170a to 170f and place one in each of the grooves of different eccentric rolls, or use 3 eccentric rolls to get 2: 1: 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, 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. 12 (b), the tension of the wire hanging in the groove of the eccentric roll portion 170b is the most relaxed. 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 A steel cord of the present invention having a 1 × 5 structure was produced using the twisting machine shown in FIG. Use a wire with a diameter of 0.35 mm, a twisting pitch P of 18 mm, a twisting direction of S, an eccentric roll with a groove circumference of 94.2 mm, and an eccentricity of 2 mm. Eccentric roll part 170a: 170b: 170c: 170d: 170e
= 1 piece: 1 piece: 1 piece: 1 piece: 1 wire is used, and 5 holes are arranged at equal intervals and on the same circumference as the wiring board. Were sequentially passed through the holes of the wiring board in the clockwise direction to create a bunched cord. As a result, a steel cord having a cord diameter of 1.06 mm and a length of 180 mm, a strand crossing frequency F of 32 times, and a cross section perpendicular to the cord longitudinal direction shown in FIG. 7 was obtained. The properties of this steel cord were measured. As a result, tensile strength: 380kgf / m
m ² , cutting load: 139.4 kgf, rubber adhesion (by peel method): 90%, rubber permeability (air that penetrates in the longitudinal direction inside the cord by applying air pressure of 5 atm to the end of the cord embedded in rubber) Amount of cc / min): 0cc / mi
n, Fatigue property (according to 3-roll method): 18787 times of characteristics were obtained, and the buckling test 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 it has good mechanical properties such as fatigue resistance and buckling resistance. I understand.

Using the above steel cord as a reinforcing cord for the four belts shown in FIG. 1, the tire size is 1000R2.
Zero radial tires were created. The rubber had the following composition (parts by weight) and was vulcanized at 150 ° C. for 25 minutes. Natural rubber: 100 HAF: 50 Stearic acid: 1 ZnO: 5 3 C:
3 Sulfur: 2 Vulcanization accelerator: 1.5 Anti-aging agent: 0.5 Belt thickness was 21 mm, cord spacing was 2.2 mm, and cord angle was 4 degrees for all 4 belts. In the carcass, ordinary steel cords (3 + 9 + 15 × 0.175 + 1) were arranged at a density of 13 / 2.54 cm at an angle of 90 degrees. The radial tire is filled with an internal pressure of 7.5 kg / cm ³ , and a JIS standard load is applied to the radial tire at a speed of 4
A drum test of 0 km / h was performed. For comparison, the wire diameter is 0.
A running test was also conducted on a radial tire in which a compact type steel cord in which five 35 mm strands were twisted together with an 18 mm pitch and an S twist was embedded in a belt under the above conditions. The tire was disassembled when the running time equivalent to the running distance of 25,000 km was reached, and the bending of the steel cord in each belt layer and the cord edge separation were inspected. As a result, in the product of the present invention, the bending of the steel cord and the cord edge separation were zero. On the other hand, the comparative product had 15% of cord breakage and 25% of cord edge separation. From this, it can be seen that the present invention has high durability against shear strain at the edge of the belt and has excellent proof stress against bending strain.

[0024]

As described above, according to the first to third aspects of the present invention, the rubber permeability and the adhesion to the rubber are good, and the strand assembly has a good cohesion, fatigue resistance and cord. Since a steel cord that is strong against axial compression pressure is used, separation phenomenon with rubber due to belt edge shear strain can be reliably prevented, and durability against strain due to lateral force can be improved. That is an excellent effect. Claims 7 and 8
According to the method, the steel cord having the above characteristics can be manufactured economically and efficiently in one step, so that an excellent effect that the belt cost and the tire cost can be reduced can be obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an example of a radial tire according to the present invention.

FIG. 2 is a schematic enlarged view of the belt layer of FIG.

FIG. 3 is a side view showing an example of a steel cord according to the present invention.

FIG. 4 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.

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

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

FIG. 10 is a cross-sectional view showing another example of the steel cord according to the present invention.

FIG. 11 is an explanatory view showing an example of a steel cord manufacturing apparatus according to the present invention.

FIG. 12 is an explanatory view illustrating an eccentric roll used in the apparatus of FIG.

FIG. 13 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 Strands a Parallel parts b Crossing parts C Gap 10 Steel cords 13a, 13b, 13c, 13d Belts

Claims (8)

[Claims] 1. A radial tire at least partially reinforced with a steel cord of 1 × n structure in which three or more strands are twisted at the same twist direction and at the same twist pitch,
In the steel cord, 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 perpendicular to the cord longitudinal direction is sequentially changed. Radial tires with open contours throughout. 2. The number of strands is 3 or more and 7 or less, and the strand crossing frequency F is 0.5 ≦ (F × P) / L ≦ in the relation between the cord length L and the twist pitch P. The radial tire according to claim 1, wherein a steel cord in the range of 4.0 is used for the belt layer. 3. The strand crossing frequency F is 0.5 ≦ (F × P) / L ≦
The radial tire according to claim 2, which is in a range of 2.0. 4. The deviation according to claim 1, wherein 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. Radial tire described in. 5. The radial according to claim 1, wherein the crossing of the strands includes a case where two or more adjacent strands are parallel to each other and intersect one or more other strands. tire. 6. The radial tire according to claim 1, wherein the strand has a diameter of 0.1 to 0.45 mm. 7. A steel cord is produced by periodically changing the arrangement of the individual strands supplied to the stranding machine in the twisting area and replacing one or more adjacent strands. The radial tire according to any one of claims 1 to 6. 8. A periodical change in the twisting area of the array of strands passes through a roll eccentric to the axis while keeping the supply length of the strands substantially constant, and then multiple holes are formed in the same circle. The process is performed by passing a wiring board arranged on the circumference.
Radial tire described in.