JP2008297686A - Steel cord for reinforcement of rubber goods, and method for production of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel cord for reinforcement of rubber goods, which has a single layered structure and has excellent rubber intrusion property, fatigue resistance, and small low load elongation. <P>SOLUTION: All element wires 11 are formed to have a helical shape and then pressed to have a kink with a small pitch for being twisted into a sine wave shape, twisting these element wires to form a single layer twisted structure, pressing them from a direction perpendicular to the longitudinal direction of the cord to obtain the cord 10 in which the cavity in the center of cord communicates with exterior through a space 12 between element wires 11, and at least a pair of the adjacent element wires 11 are mutually and substantially contacting each other at any point of the longitudinal direction of the cord, and partially, substantially and parallelly contacting at a non-continuous position of the longitudinal direction of the cord. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a steel cord for reinforcing rubber products (hereinafter sometimes simply referred to as “cord”) used as a reinforcing material for rubber products such as automobile tires and conveyor belts.

  Conventionally, as a steel cord for reinforcing a rubber product of a single layer structure used as a rubber product reinforcing material for an automobile tire, a conveyor belt or the like, a single layer twist of a 1 × 3, 1 × 5 structure or the like is used. A so-called closed twisted cord in which the wires are tightly twisted and brought into close contact is generally used. However, this closed twisted cord has a closed cavity at the center of the cord, and when the composite sheet is formed by sandwiching the cord between two rubber sheets to form a composite sheet, the rubber material is centered on the cord. A so-called perfect composite in which the rubber and cord are integrated by the rubber material completely entering the cavity in the center of the cord without entering the cavity and simply wrapping the cord with a rubber sheet I can't become a body For this reason, when a composite sheet obtained by heating and compressing a conventional closed twisted cord between rubber sheets is incorporated into an automobile tire, for example, the adhesion between the rubber material and the cord is insufficient, and the rubber material peels off from the cord when the automobile is running. In other words, when the moisture that has entered the rubber material reaches the cavity in the center of the cord, the moisture propagates along the cavity and in the longitudinal direction of the cord. There is the problem that it will corrode, resulting in a significant reduction in the mechanical strength of the cord.

  Moreover, as shown in FIG. 6, with the cord 30 having a single-layer stranded structure, excessively squeezing for twisting to be performed on all of the plurality of strands 31, the strands 31 can be connected to each other. A cord having an open twist structure is also known in which a gap 32 is formed in the rubber member so that a rubber material can easily enter. However, cords with an open twisted structure are not in contact with each other, are easily deformed, and have a large elongation in an extremely low load region (hereinafter referred to as “low load elongation”), so handling workability is high. bad. Furthermore, the gap 32 may be reduced due to the extremely low load tension applied when the composite sheet is formed, and the rubber material may not sufficiently enter the cord.

  Further, as shown in FIG. 7, the cord 40 having a single-layer twisted structure has a small spiral comb different from the twist for twisting a part of the strands 41 of the strands 41. It has been proposed to be used (see, for example, Patent Document 1). This cord consists of an element wire (hereinafter referred to as “spiral element wire”) provided with a small helix that is different from the one used for twisting and an element wire (hereinafter referred to as a “helix element wire”). , "Non-spiral strands"), which are tightly twisted together, and the strands are in close contact with each other and twisted together. A gap 42 is formed between the spiral strands and the rubber material enters.

  However, a single layer twisted structure cord in which only a part of the strands are provided with a spiral warp tends to concentrate the tensile load on the non-spiral strand when a tensile load is applied to the cord. .

  Therefore, as shown in FIG. 8, it is also conceivable that all the strands 51 are spiral strands with a cord 50 having a single-layer twisted structure. By doing so, a gap 52 in which the rubber material enters between the strands 51 is formed, and the tensile load is shared by all the strands, so that the fatigue resistance is not lowered due to the concentration of the tensile load. However, when all the strands 51 are spiral strands as described above, the low load elongation of the cord 50 increases.

Japanese Patent Laid-Open No. 5-140882

  Accordingly, it is an object to obtain a steel cord for reinforcing rubber products having a single-layer twist structure that has good rubber penetration, excellent fatigue resistance, and low low load elongation.

  The above problem is that a steel cord having a single layer twist structure of 1 × n (n = 3 to 6) in which n strands having the same wire diameter are twisted together is a habit for all the strands to be twisted together. In addition, a cord having a pitch smaller than the twist for twisting, the cavity at the center of the cord communicates to the outside through a gap between the strands, and at least at any location in the longitudinal direction of the cord The problem can be solved by configuring such that any one set of adjacent strands are substantially in contact with each other.

  In this cord, all the strands have a smaller pitch than the twisted strands apart from the twisted strands, and the cavity in the center of the cord is connected to the outside via the gap between the strands. Because it communicates with the rubber material, rubber material easily enters.

  Also, this cord has all the strands with a smaller pitch than the twist for twisting, and when a tensile load is applied to the cord, the load is applied equally to all the strands. There is no decrease in fatigue resistance due to the concentration of the load on the strands of steel, and the fatigue resistance is excellent.

  Furthermore, in this cord, at least any one set of adjacent strands are substantially in contact with each other at any location in the longitudinal direction of the cord, whereby the cord elongation becomes small and low load elongation can be suppressed.

  In addition, the above-described problem is that a steel cord having a single layer twist structure of 1 × n (n = 3 to 6) obtained by twisting n strands having the same wire diameter is used for twisting all strands. Apart from the habit, it has a habit with a smaller pitch than the habit for twisting, the hollow part of the cord center communicates to the outside through the gap between the strands, and the adjacent strands are the cord center The problem can be solved by configuring such that the portions that are in contact with each other in substantially parallel so as to be substantially parallel to the shaft are partially present in a discontinuous arrangement in the longitudinal direction of the cord.

  In this cord, all the strands have a smaller pitch than the twisted strands apart from the twisted strands, and the cavity in the center of the cord is connected to the outside via the gap between the strands. Because it communicates with the rubber material, rubber material easily enters.

  Also, this cord has all the strands with a smaller pitch than the twist for twisting, and when a tensile load is applied to the cord, the load is applied equally to all the strands. There is no decrease in fatigue resistance due to the concentration of the load on the strands of steel, and the fatigue resistance is excellent.

  Furthermore, this cord has a small cord elongation due to the discontinuous arrangement in the cord longitudinal direction where the adjacent strands are in contact with each other so as to be substantially parallel to the cord central axis. Thus, low load elongation can be suppressed.

The above-mentioned problem is a steel cord having a single layer twist structure of 1 × n (n = 3 to 6) in which n strands having the same wire diameter are twisted, and all the strands are twisted together. In addition to the habit for twisting, it has a habit with a smaller pitch than the habit for twisting, and the cavity at the center of the cord communicates to the outside via the gap between the strands, and any cord longitudinal direction At least one pair of adjacent strands is also in contact with each other at the location, and the locations where the adjacent strands are in contact with each other in parallel so that the strands are substantially parallel to the cord central axis are not in the longitudinal direction of the cord. The problem can be solved by configuring to be partially present in a continuous arrangement.

  In this cord, all the strands have a smaller pitch than the twisted strands apart from the twisted strands, and the cavity in the center of the cord is connected to the outside via the gap between the strands. Because it communicates with the rubber material, rubber material easily enters.

  Also, this cord has all the strands with a smaller pitch than the twist for twisting, and when a tensile load is applied to the cord, the load is applied equally to all the strands. There is no decrease in fatigue resistance due to the concentration of the load on the strands of steel, and the fatigue resistance is excellent.

  Further, in this cord, at any location in the longitudinal direction of the cord, at least any one pair of adjacent strands are substantially in contact with each other, and the adjacent strands are substantially parallel to the cord central axis. Since the portions that are in contact with each other in parallel are partially present in a discontinuous arrangement in the longitudinal direction of the cord, the cord elongation is reduced and low load elongation can be suppressed.

  In the cord having the above-described configuration, the habit having a smaller pitch than the habit for twisting is preferably a habit obtained by pressing a strand after forming a helical habit on the strand. Even if a wire is passed between a pair of gears whose teeth have been processed into a desired shape, a small wrinkle can be obtained by bending the wire into a zigzag shape. The degree of work becomes greater than the part where there is not, stress remains in the bent part where the degree of work is large, and stress due to external force is added to this, so that the stress at the bent part becomes excessive and the fatigue resistance decreases. On the other hand, the wrinkle obtained by applying a pressing process after a helical wrinkle has a uniform degree of processing at any location, so that excessive stress does not act on it and it has excellent fatigue resistance. Become.

  Further, the pitch P1 is P1 = 0.2Pc to 0.5Pc (where Pc is the pitch of twisting) and the wave height h is h = 0.2d to It is preferably 2.0d (where d is the wire diameter). If the pitch P1 is smaller than 0.2 Pc, excessive plastic deformation is applied to cause excessive stress at the time of soldering, so that the strands are easily broken and the productivity is lowered, and the pitch P1 is less than 0.5 Pc. If it is large, the gap between the wires decreases due to the tensile force caused by the flow of the rubber material during molding of the rubber product or the ironing force applied to the surface of the cord, and the rubber material does not sufficiently penetrate. Also, if the wave height h is less than 0.2d, the gap between the wires becomes too small, and even if a rubber material with good fluidity is used, the rubber material can sufficiently penetrate into the interior during pressure vulcanization. If the wave height h is larger than 2.0d, the twist stability is deteriorated and the fatigue resistance is deteriorated. Note that the values of the pitch P1 and the wave height h, which have a smaller pitch than the twists for twisting, coincide with those of the strands obtained by untwisting the cord.

  The steel cord for reinforcing a rubber product having a single layer twist structure of 1 × n (n = 3 to 6) in which n strands having the same wire diameter of the present invention are twisted together is spirally attached to all the strands. After pressing, the steel cord having a single-layer twist structure is formed by twisting the strands having a substantially smaller two-dimensional wave shape than the twist for twisting and twisting the strands having the substantially two-dimensional wave shape. It can be manufactured by forming and pressing the steel cord from a direction perpendicular to the longitudinal direction of the cord.

  In this way, by applying a pressing process from a direction orthogonal to the longitudinal direction to a steel cord of a single-layer twisted structure made of strands having a substantially two-dimensional wavy comb, all the strands are a twist for twisting together. Separately, it has a pitch smaller than that for twisting, the gap between the strands communicates with the outside, and at least one set of adjacent strands at any location in the longitudinal direction of the cord The cords are substantially in contact with each other, and the portions where the adjacent strands are in contact with each other in parallel so that the strands are substantially parallel to the cord central axis are partially present in a discontinuous arrangement in the cord longitudinal direction. It becomes.

  In this manufacturing method, the strands are wound with a helical bevel and then processed by pressing to form a substantially two-dimensional wavy beak on a reel, etc. It may be set and twisted together, or it may be subjected to a squeezing process from the feeder of the twisting machine to the twisting opening.

  According to the present invention, it is possible to obtain a steel cord for reinforcing a rubber product having a single-layer twist structure that has good rubber penetration, excellent fatigue resistance, and low low load elongation. By using it as a material, a tire excellent in rubber penetration and fatigue resistance can be produced without deteriorating handling workability at the time of tire production, and the life of the tire can be greatly extended.

  In addition, this cord is made by applying a twisting of the strands of the wire to the one obtained by press working, so that the degree of processing becomes uniform, excessive stress does not act, and fatigue resistance It can be made excellent.

  Also, this cord is in the state of the strand after untwisting, and the pitch P1, which is smaller than the twist for twisting, is P1 = 0.2Pc to 0.5Pc (where Pc is twisted) (Pitch), it is possible to avoid unreasonable plastic deformation and increase productivity. Also, the tensile force caused by the flow of rubber during molding of rubber products, or the ironing force applied to the cord surface Thus, the gap between the strands can be prevented from decreasing, and the rubber material can sufficiently penetrate. In addition, by setting the wave height h of the substantially two-dimensional wavy habit to h = 0.2d to 2.0d (where d is the wire diameter), the rubber material can sufficiently penetrate into the inside and the fatigue resistance is deteriorated. You can avoid it.

  Hereinafter, a steel cord for reinforcing rubber products according to an embodiment of the present invention (hereinafter referred to as “steel cord” or simply “cord”) will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional structure of a 1 × 3 steel cord as an example of an embodiment of a 1 × n (n = 3 to 6) single-layer twisted structure.

  The cord (steel cord) 10 shown in FIG. 1 is a 1 × 3 single-layer stranded structure composed of three strands 11 having the same wire diameter, and is pressed after all the strands 11 are provided with a helical wrinkle. Processed and twisted with a sinusoidal shape with a pitch smaller than the twist for twisting, and the single layer twisted cord thus formed is pressed from the direction perpendicular to the cord longitudinal direction .

  In the cord 10, all the strands 11 have a pitch and a wave height smaller than the twist for twisting apart from the twist for twisting. The habit having a smaller pitch and wave height than the habit for twisting is a habit obtained by applying a helical helix to the strands and then pressing the strands. It is.

  The substantially sinusoidal habit of the strands 11 before twisting is as shown in FIG. 3, and the pitch means the length (period) P1 from the valley of the wave to the valley or from the peak to the peak. The height (amplitude) h from the valley of the wave to the mountain is meant. On the other hand, the small pitch having a different pitch from the twist for twisting the strands 11 in the state of the cord 10 after twisting is substantially the same as that remaining on the strand 11 that is untwisted from the cord 10 and taken out. Thus, it has a shape in which a habit for twisting and a habit for twisting, which are different from the habit for twisting, are synthesized. And for twisting based on the habit for twisting in the habit of the strand 11 in the state of the cord 10 after twisting (substantially the same as the habit remaining in the strand 11 taken out by twisting) The shape of the small spider with a different pitch from that of the spear is a substantially two-dimensional wavy habit that approximates the substantially sinusoidal wrinkle of the strands 11 before twisting. , P1 = 0.2Pc to 0.5Pc (where Pc is the twisting pitch), and the wave height h is h = 0.2d to 2.0d (where d is the wire diameter). In addition, it is preferable that the strand diameter d is 0.15-0.40 mm. If it is less than 0.15 mm, the strength of the steel cord is lowered, and if it exceeds 0.40 mm, the flexibility is deteriorated. The twist pitch Pc is usually 8.0 to 18.0 mm.

  The cord 10 has a gap 12 as shown in FIG. 1 between at least one pair of adjacent strands 11 at any location in the longitudinal direction of the cord, and a hollow portion at the center of the cord is formed. As shown in FIG. 1, at least any one pair of adjacent strands 11 communicates with the outside and is substantially in contact with each other at any location in the longitudinal direction of the cord.

  In addition, as shown in FIG. 4, the cord 10 is contacted in approximately parallel so that adjacent strands 11 are discontinuously arranged in the longitudinal direction of the cord and partially parallel to the central axis of the steel cord, The twist angle α of the strand 11 is 0 (zero) at a location (range) A that contacts in parallel.

  When three strands 11 having a small sine wave shape are twisted to form a cord, and this cord is pressed from a direction perpendicular to the longitudinal direction of the cord, the three strands 11 are arranged in the longitudinal direction of the cord. As shown in FIG. 1, at least any one pair of adjacent strands 11 at any location is substantially in contact with each other, and is periodically blended with an interval in the longitudinal direction of the cord and a predetermined twist angle α. And a portion that contacts each other in a substantially parallel manner, and a twisted structure as shown in FIG. 4 is obtained.

  In this cord 10, all the strands 11 have a smaller pitch than the twist for twisting apart from the twist for twisting, so that the cavity at the center of the cord has a gap 12 between the strands 11. It becomes the structure which communicates outside via. Therefore, the rubber material easily enters.

  Further, the cord 10 has all the strands 11 having a smaller pitch than the twist for twisting, and when a tensile load is applied to the cord, the load is applied equally to all the strands 11. The fatigue resistance does not decrease due to the concentration of the load on some of the strands 11, and the fatigue resistance is excellent.

  Further, in this cord 10, at least any one pair of adjacent strands 11 is substantially in contact with each other at any location in the longitudinal direction of the cord, and the adjacent strands 11 are substantially parallel to the cord central axis. Since the portions in contact with each other in a substantially parallel manner are partially present in a discontinuous arrangement in the longitudinal direction of the cord, the cord elongation is reduced and low load elongation can be suppressed.

  FIG. 2 shows a cross-sectional structure of a steel cord having a 1 × 5 structure as another example of an embodiment having a single-layer twisted structure of 1 × n (n = 3 to 6).

  The cord (steel cord) 20 shown in FIG. 2 is a 1 × 5 single-layer twisted structure composed of three strands 21 having the same wire diameter, and is pressed after all strands 21 are provided with a helical crinkle. Processed and twisted with a sinusoidal shape with a pitch smaller than the twist for twisting, and the single layer twisted cord thus formed is pressed from the direction perpendicular to the cord longitudinal direction .

  In the cord 20, all the strands 21 have a pitch and a wave height smaller than the twist for twisting apart from the twist for twisting. The habit having a smaller pitch and wave height than the habit for twisting is a habit obtained by applying a helical helix to the strands and then pressing the strands. It is.

  In the case of the cord 20 as well, the pitch P1 is set to P1 = 0.2Pc to 0 in a small two-dimensional wave-like comb having a small pitch different from the twisting twist based on the twisting twist. 0.5 Pc (where Pc is the twisting pitch) and the wave height h is h = 0.2d to 2.0d (where d is the wire diameter). In addition, it is preferable that the strand diameter d is 0.15-0.40 mm. If it is less than 0.15 mm, the strength of the steel cord is lowered, and if it exceeds 0.40 mm, the flexibility is deteriorated. The twist pitch Pc is usually 8.0 to 18.0 mm.

  The cord 20 has a gap 22 between at least one pair of adjacent strands 21 at any location in the longitudinal direction of the cord as shown in FIG. As shown in FIG. 2, at least any one pair of adjacent strands 21 communicates with the outside and is substantially in contact with each other at any location in the longitudinal direction of the cord.

  Further, as shown in FIG. 5, the cord 20 is contacted in a substantially parallel manner so that adjacent strands 21 are discontinuously arranged in the longitudinal direction of the cord and are partially parallel to the central axis of the steel cord, The twist angle α of the strand 21 is 0 (zero) at a location (range) A that is in contact with the substantially parallel.

  When five strands 21 having small sine wave-like small strands are twisted to form a cord, and this cord is pressed from the direction orthogonal to the cord longitudinal direction, the five strands 21 are arranged in the cord longitudinal direction. As shown in FIG. 2, at least any one pair of adjacent strands 21 in any part is in substantially contact with each other, and is periodically blended with an interval in the longitudinal direction of the cord to have a predetermined twist angle α. And a portion that contacts each other in a substantially parallel manner and has a twisted structure as shown in FIG.

  In the cord 20, all the strands 21 have a smaller pitch than the twist for twisting apart from the twist for twisting, so that the hollow portion in the center of the cord has a gap 22 between the strands 21. It becomes the structure which communicates outside via. Therefore, the rubber material easily enters.

  Further, the cord 20 has all the strands 21 having a smaller pitch than the twist for twisting, and when a tensile load is applied to the cord, the load is applied equally to all the strands 21. The fatigue resistance does not decrease due to the concentration of the load on some of the strands 21, and the fatigue resistance is excellent.

  Further, in this cord 20, at least any one pair of adjacent strands 21 is substantially in contact with each other at any location in the longitudinal direction of the cord, and the adjacent strands 21 are substantially parallel to the cord central axis. Since the portions in contact with each other in a substantially parallel manner are partially present in a discontinuous arrangement in the longitudinal direction of the cord, the cord elongation is reduced and low load elongation can be suppressed.

  As an example, a steel wire having a diameter of 5.5 mm was repeatedly subjected to patenting and wire drawing, and then subjected to brass plating on the surface to form a strand having a wire diameter of 0.25 mm. Single layer stranded steel cords with x3 and 1x5 structures were produced.

  The single-layer twisted cords of the 1 × 3 structure and the 1 × 5 structure in these examples are each formed by forming a helical wrinkle and then pressing the pressing process into a small sinusoidal wrinkle (with a pitch higher than that of the twist for twisting). Manufactured by twisting the strands with small sinusoidal wrinkles, twisting the strands with the small sinusoidal shape, and pressing the single-layer twisted cord thus formed from the direction perpendicular to the longitudinal direction of the cord. It is.

  In any case, the helical wrinkle was applied using a wrinkle device that rotates using the supplied strand as an axis (Japanese Patent Publication No. 63-63293). The comb shape was adjusted by the spacing of the tacking pins, the dimension of the tacking pins, and the number of rotations rotating around the element wire.

  Moreover, the pressing process which processes a helical comb into a substantially sinusoidal pattern and the pressing process after the stranded wire processing were performed by a known pressing device in which a plurality of freely rotating rollers are arranged in a staggered manner. However, the pressing means is not limited to these.

  The cords of the examples thus produced were evaluated for rubber penetration, low load elongation, and fatigue resistance compared to the cords of the conventional examples.

  For rubber penetration, each cord is embedded in a rubber material under a tensile load of 49 N, pressure vulcanized, the cord is taken out, the cord is disassembled and a certain length is observed, and the observed length The ratio of the length of traces in contact with rubber to the percentage was evaluated as a percentage.

  The low load elongation was evaluated by expressing the elongation at a load of 49 N as a percentage.

  For fatigue resistance, a composite sheet is created by embedding a plurality of cords in a rubber material, and this sheet is used to create a composite sheet until the cord breaks through fretting wear, buckling, etc. The number of repetitions was determined, and the index was displayed with the closed twist cord of the conventional example as 100.

  The handling operability was evaluated as x for the inferior one compared to the closed twisted cord of the conventional example, Δ for the slightly inferior one, and ○ for the equivalent one.

  In the conventional example, a steel wire having a diameter of 5.5 mm is subjected to patenting and wire drawing, and then the surface is subjected to brass plating to form a strand having a wire diameter of 0.25 mm. Three types of cords, a conventional 1 × 3 structure with a closed structure, an open structure, and a cord with a spiral knotting on all strands, and a closed structure, an open structure with a 1 × 5 structure, In addition, three types of cords having a conventional 1 × 5 structure of cords in which all the strands were spirally kneaded were manufactured.

表１から、実施例のコードは全ての評価で従来コードより優れていることが明らかである。 The evaluation results are shown in Table 1.

From Table 1, it is clear that the code of the example is superior to the conventional code in all evaluations.

It is sectional drawing of the steel cord of the 1 * 3 single layer twist structure of embodiment of this invention. It is sectional drawing of the steel cord of the 1 * 5 single layer twist structure of embodiment of this invention. It is explanatory drawing of the pitch and wave height of the substantially sinusoidal habit which concerns on embodiment of this invention. It is explanatory drawing of the twist structure which concerns on an example of embodiment of this invention. It is explanatory drawing of the twist structure which concerns on the other example of embodiment of this invention. It is sectional drawing of the steel cord of the open structure which made the excess for the twist for the twisting of all the strands by the conventional 1x3 single layer twist structure. FIG. 3 is a cross-sectional view of a steel cord having a conventional 1 × 3 single-layer twisted structure in which one strand has a spiral bend different from the bend for twisting. It is sectional drawing of the steel cord which is a conventional 1x3 single layer twisted structure, and all the strands have a helical habit different from the habit for twisting.

Explanation of symbols

10, 20 cord (steel cord)
11, 21 Wire 12, 22 Clearance

Claims (6)

This is a 1 × n (n = 3-6) single layer twisted steel cord in which n strands having the same wire diameter are twisted, and all the strands are separated from the habit for twisting. It has a habit with a pitch smaller than the habit for twisting, the cavity in the center of the cord communicates to the outside through a gap between the strands, and at least at any location in the longitudinal direction of the cord A steel cord for reinforcing rubber products, characterized in that a pair of adjacent wires are substantially in contact with each other. This is a 1 × n (n = 3-6) single layer twisted steel cord in which n strands having the same wire diameter are twisted, and all the strands are separated from the habit for twisting. Has a pitch smaller than the twist for twisting, the cavity in the center of the cord communicates with the gap between the strands, and the adjacent strands are substantially parallel to the cord center axis The steel cord for reinforcing rubber products is characterized in that the portions that are substantially parallel to each other are partially present in a discontinuous arrangement in the longitudinal direction of the cord. This is a 1 × n (n = 3-6) single layer twisted steel cord in which n strands having the same wire diameter are twisted, and all the strands are separated from the habit for twisting. It has a habit with a pitch smaller than the habit for twisting, the cavity in the center of the cord communicates to the outside through a gap between the strands, and at least at any location in the longitudinal direction of the cord A pair of adjacent strands are substantially in contact with each other, and the portions where the adjacent strands are substantially parallel to each other so as to be substantially parallel to the cord central axis are partially discontinuous in the cord longitudinal direction. Steel cord for reinforcing rubber products, characterized by 4. The steel cord for reinforcing rubber products according to claim 1, 2 or 3, wherein the habit having a smaller pitch than the habit for twisting is a habit obtained by pressing a strand after forming a helical habit on the strands. The pitch smaller than the twist for twisting is that the pitch P1 is P1 = 0.2 Pc to 0.5 Pc (where Pc is the pitch of twisting), and the wave height h is h = 0.2 d to 2 The steel cord for reinforcing rubber products according to claim 1, 2, 3 or 4, wherein the steel cord is 0.0d (where d is a wire diameter). A method of manufacturing a steel cord for reinforcing a rubber product having a single-layer twist structure of 1 × n (n = 3 to 6) in which n strands having the same wire diameter are twisted together, and spirally formed on all the strands Steel with a single-layer twisted structure that is pressed after being subjected to pressing and having a two-dimensional wave shape with a pitch smaller than the twist for twisting, and strands having the two-dimensional wave shape are twisted together A method for producing a steel cord for reinforcing rubber products, comprising forming a cord and pressing the steel cord in a direction perpendicular to the longitudinal direction of the cord.

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