JP2010159527A - Steel cord for reinforcing rubber product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel cord for reinforcing a rubber product used as a reinforcement of the rubber product such as a vehicular tire or an industrial belt with an ultraflat shape and excellent fatigue resistance. <P>SOLUTION: The steel cord of an N+N structure or N+(N+1) structure in which N or N+1 wires to be a side are twisted together around the core having N (N=3-4) wires is arranged so that all the wires (1-3) of the core are mutually nearly parallel and arranged in one direction in a nearly linear state in a cord cross section to thereby provide an ultraflat cord cross-sectional shape. Furthermore, the wires (1-3) of the core assume a waveform in which phases are mutually uniform in the cord longitudinal direction, and the amplitude d of the waveform and the wire diameter D satisfy 1.1&le;d/D&le;2.4. Thereby, the wires (1-3) of the core readily extend to disperse a tensile load in the wires (1-3) of the core and wires (4-6) of the side. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a steel cord for reinforcing rubber products used as a reinforcing material for rubber products such as vehicle tires and industrial belts.

  As a steel cord for reinforcing rubber products (hereinafter, also simply referred to as steel cord or cord) used as a reinforcing material for rubber products such as tires and belts, the side around the core (core) consisting of a plurality of strands ( There is a steel cord in which multiple strands that form a sheath are twisted together. For example, in a steel cord having a 2 + 2 structure with two core wires and two side wires, the two core wires are substantially parallel and do not twist each other. It has been conventionally known that the two strands of wire are twisted with each other in the same direction and pitch as the twisting direction and pitch of the core and the side (see, for example, Patent Document 1).

  In this way, the steel cord of the 2 + 2 structure is such that the two strands that become the core are substantially parallel and do not twist each other, and the two strands that are the sides are in the direction of twisting between the core and the side and By twisting each other in the same direction and pitch as the pitch, rubber penetration can be ensured, and two strands that are substantially parallel and have no twists in the core are crossed in the cord cross section. It is arranged in one direction, and the two strands on the side are twisted together, so that the cord cross-section is thin and flat in the height direction. For example, a rubber sheet with a plurality of cords aligned in parallel with each other When it is embedded in a tire as a reinforcing material for a tire, the thickness of the rubber sheet can be reduced, and the degree of freedom in forming the tire is increased.

  When a plurality of strands that are cores are substantially parallel and are not twisted with each other, and the plurality of strands that become the cores are arranged in one direction in the cross section of the cord, the plurality of strands on the side thereof It is not limited to a steel cord having a 2 + 2 structure that the cord cross-section becomes thin and flat in the height direction by being twisted together. Even in the case of a steel cord with a 3 + 3 structure with three core wires and two side wires, or a 4 + 5 structure steel cord with four core wires and five side wires When the three or four strands are substantially parallel and are not twisted with each other, the three or four core strands are arranged in a straight line in one direction in the cord cross section. The cross-sectional shape of the cord is increased by twisting three strands (when there are three core wires) or five strands (when there are four core wires). It becomes a relatively thin super flat shape. That is, a steel cord of N + N structure or N + (N + 1) structure in which N or (N + 1) strands on the side are wound around a core made of N (N = 3 to 4) strands is A steel cord having a super-flat cross-sectional shape can be obtained by adopting a configuration in which all of the N strands serving as the core are substantially parallel to each other and arranged in one direction in a substantially straight line in the cord cross-section.

  Separately, for example, in a steel cord of 3 + 3 structure, a virtual line connecting the centers of three strands that become cores in the cross section of the cord is arranged side by side in a straight line or an obtuse triangular shape, and the three cores that become the core It is known that at least one strand is corrugated to promote the penetration of rubber into the core (for example, see Patent Document 2).

Japanese Examined Patent Publication No. 2-29408 JP-A-9-175112

  As described above, steel of N + N structure or N + (N + 1) structure in which N or (N + 1) strands are twisted around a core consisting of N (N = 3 to 4) strands. For example, in the case of a cord having a 3 + 3 structure, the cord has a cross-sectional shape in which all three core wires serving as the core are substantially parallel to each other and arranged substantially in a straight line in the cord cross section. Can be a super flat steel cord. However, for example, in the case of a 3 + 3 structure cord, when all of the three core wires that are the cores are substantially parallel to each other, the three core wires that are the cores are generally substantially straight and these three wires A core made of a substantially straight wire is positioned at the center in a state that is substantially straight in the longitudinal direction of the cord, and is twisted so that the strand on the side is wrapped around this substantially straight core It becomes. In this case, the cord is in a state in which the strand on the side is easier to extend than the strand of the core. Therefore, when a tensile load is applied to the cord and the cord is stretched, the tensile load is not evenly distributed and acts on the core strand and the side strand, but is biased toward the core strand (tensile load) Will act, resulting in poor fatigue resistance. That is, it is possible to make a super flat cord with a configuration in which three strands as cores are arranged in one direction in a substantially straight line in the cord cross section, and two strands on the side are twisted around each other. However, the fatigue resistance cannot be sufficiently increased.

  Further, as described above, for example, a steel cord having a 3 + 3 structure, a virtual line connecting the centers of three strands that are cores in the cord cross section is arranged in a side-by-side arrangement in a straight line or an obtuse triangular shape, and the three cores There are some that have been made to promote the penetration of rubber into the core by corrugating at least one of the strands, in which at least one of the core strands is straight However, it is considered that the bias of the tensile load is alleviated for the strands, but even in that case, the tensile load is not necessarily distributed evenly to all of the core strands and the side strands. In addition, the corrugation applied to the core wire to promote the penetration of rubber is preferably such that the direction of the wave height is transverse to the side-by-side direction of the core wires. Wavy , In which case the code cross-sectional shape is not a flat.

  Also, even if the core strand is straight in the state of the strand before twisting the cord, if the cord twist pitch is reduced, the core strand will also be twisted in the cord state, The force applied to the core wire when the tensile load is applied is somewhat relaxed, but there is a limit to this, and if the twist pitch is reduced, the productivity of the cord deteriorates.

  An object of the present invention is to make a steel cord for reinforcing a rubber product used as a reinforcing material for a rubber product such as a vehicle tire or an industrial belt flat and excellent in fatigue resistance.

    The steel cord for reinforcing rubber products of the present invention has an N + N structure or N + in which N or (N + 1) strands are twisted around a core made of N (N = 3 to 4) strands. A steel cord having a (N + 1) structure, in which all the N strands serving as the core are parallel to each other and arranged in one direction in a substantially straight line in the cord cross section, and in phase with each other in the longitudinal direction of the cord It exhibits a waveform, and the amplitude d and the wire diameter D of the waveform satisfy 1.1 ≦ d / D ≦ 2.4.

  In this steel cord, all N (N = 3 to 4) cores are parallel to each other and arranged in one direction in a substantially straight line in the cord cross section, and N or (N + 1) strands on the side around it Are twisted together so that the cross section of the cord becomes flat, and the N strands that are substantially parallel and core have a waveform in which the phases are aligned with each other in the longitudinal direction of the cord, When the amplitude d and the wire diameter D of the waveform satisfy 1.1 ≦ d / D ≦ 2.4, the core wire and the wire on the side when a tensile load is applied to the cord Are stretched together, and the tensile load is appropriately dispersed between the core wire and the side wire, resulting in a cord having high breaking strength and excellent fatigue resistance.

  If d / D> 2.4, the amplitude d of the waveform of the core wire is too large, the core wire tends to be excessively stretched, and the tensile load is biased toward the side wire, so that the cord breaks. Strength decreases and fatigue resistance deteriorates.

  Further, when d / D <1.1, the core wire has a waveform amplitude d that is too small, is nearly straight, is not easily stretched, and the tensile load is sufficiently applied to the core wire. Therefore, the breaking strength of the cord is not sufficiently increased, and the fatigue resistance is not sufficiently improved.

  According to the present invention, it is possible to make the steel cord for reinforcing rubber products flat and excellent in fatigue resistance while reducing the production cost by increasing the twist pitch. For example, when a reinforcing material such as a tire is formed by arranging a plurality of cords parallel to each other and embedded in a rubber sheet, the rubber sheet can be thin, strong, and excellent in fatigue resistance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 relates to an example of an embodiment of the present invention, (a) is a plan view of a steel cord, (b) is a side view of the steel cord, (c) is a sectional view of the steel cord, and FIG. It is explanatory drawing which shows the waveform in the cord state of the strand of the core of the steel cord shown in FIG.

  The steel cord of this embodiment is a steel cord for reinforcing rubber products that is used as a reinforcing material for vehicle tires, industrial belts, etc., and is composed of six strands (steel filaments) 1-6. The strands 1 to 6 have the same wire diameter (strand diameter), and the three strands 1 to 3 become cores, and around the core composed of the three strands 1 to 3 This is a steel cord having a 3 + 3 structure in which three strands 4 to 6 on the side are twisted together. The wire diameters of the six strands 1 to 6 are, for example, 0.20 to 0.38 mm. Further, the twist pitch of the cord is, for example, 10 to 20 mm.

  In this steel cord, all of the core wires (three core wires) 1 to 3 are substantially parallel to each other in the cord state as shown in FIGS. 1 (a) and (b), and As shown in FIG. 1 (c), waveforms are arranged in one direction (lateral direction) in a substantially straight line in the cross section of the cord, and in which the phases are aligned in the longitudinal direction of the cord as shown in FIG. 1 (a). Presents.

  The waveforms of the core strands 1 to 3 are as shown in FIG. 2, and the amplitude of the waveform (the apparent wave height of the core in the cord state) d and the strand diameter D are 1.1 ≦ d / D ≦ The relationship of 2.4 is satisfied.

  In this steel cord, all of the three strands 1 to 3 as cores are substantially parallel to each other and arranged in one direction in a substantially straight line in the cord cross section, and the three strands 4 to 6 is twisted together, the cross section of the cord becomes flat, and the three strands 1 to 3 that are substantially parallel and core form a waveform in which the phases are aligned in the longitudinal direction of the cord. When the amplitude d of the waveform and the wire diameter D satisfy 1.1 ≦ d / D ≦ 2.4, when the tensile load is applied to the cord, the wires 1 to 3 and the core that are the core The strands 4 to 6 to be stretched together, and the tensile load is appropriately dispersed in the strands 1 to 3 to be the core and the strands 4 to 6 to be the side, and the fracture strength is large and the fatigue resistance is increased. Excellent code.

  If d / D> 2.4, the amplitude d of the waveform of the core strands 1 to 3 is too large, and the core strands 1 to 3 tend to be excessively stretched. Therefore, the breaking strength of the cord is lowered and the fatigue resistance is deteriorated. Moreover, when d / D <1.1, the core wires 1 to 3 have a waveform amplitude d that is too small, is nearly straight, hardly stretched, and the tensile load is reduced to the core wires 1 to 3. Since it is not possible to sufficiently relax the bias, the cord breaking strength is not sufficiently increased, and the fatigue resistance is not sufficiently improved.

  Moreover, although the example of illustration is embodiment applied to the steel cord of 3 + 3 structure, this invention can be applied also to 3 + 4 structure. In this case, the steel cord (not shown) is composed of seven strands (steel filaments), and these seven strands have the same wire diameter (strand diameter) and three strands are cores ( A steel cord having a 3 + 4 structure in which four strands serving as side strands are twisted around a core composed of the three strands. The wire diameter of the seven strands is, for example, 0.20 to 0.38 mm. Further, the twist pitch of the cord is, for example, 10 to 20 mm.

  Furthermore, the present invention can be applied to a 4 + 4 structure. In this case, the steel cord (not shown) is composed of eight strands (steel filaments), and these eight strands have the same wire diameter (strand diameter), and the four strands are cores ( This is a 4 + 4 steel cord in which four strands serving as side strands are twisted around a core composed of the four strands. The wire diameter of the eight strands is, for example, 0.20 to 0.38 mm. Further, the twist pitch of the cord is, for example, 10 to 20 mm.

  The present invention can also be applied to a 4 + 5 structure. In this case, the steel cord (not shown) is composed of nine strands (steel filaments), and these nine strands have the same wire diameter (strand diameter), and the four strands are cores ( This is a steel cord having a 4 + 5 structure in which five strands serving as side strands are twisted around a core composed of the four strands. The diameter of the nine strands is, for example, 0.20 to 0.38 mm. Further, the twist pitch of the cord is, for example, 10 to 20 mm.

  The steel cord has a waveform in which the core strands are all substantially parallel to each other in the cord state, and are arranged in one direction (lateral direction) in a substantially straight line in the cord cross section, and in phase with each other in the cord longitudinal direction. Presents. The waveform of the core wire is still as shown in FIG. 2, and in this case, the amplitude of the waveform (the apparent wave height of the core in the state of the cord) d and the wire diameter D are 1.1 ≦ d. The relationship of /D≦2.4 is satisfied.

  In the steel cord, all of the N strands (N = 3 or 4) serving as cores are substantially parallel to each other and arranged in one direction in a substantially straight line in the cord cross section, and the strands on the sides around the strands ( N or N + 1) are twisted together so that the cross section of the cord has a flat shape, and the N strands that are substantially parallel to each other in the core have a waveform in which the phases are aligned in the longitudinal direction of the cord. When the cord has a tensile load, the amplitude d and the wire diameter D of the waveform satisfy 1.1 ≦ d / D ≦ 2.4. The strands are stretched together, and a tensile load is appropriately dispersed between the core strand and the side strand, resulting in a cord having high breaking strength and excellent fatigue resistance.

  In this case, if d / D> 2.4, the amplitude d of the waveform of the core wire is too large, the core wire tends to extend excessively, and the tensile load is biased toward the side wire, The breaking strength of the cord is lowered and the fatigue resistance is deteriorated. Further, when d / D <1.1, the core wire has a waveform amplitude d that is too small, is nearly straight, is not easily stretched, and the tensile load is sufficiently applied to the core wire. Therefore, the breaking strength of the cord is not sufficiently increased, and the fatigue resistance is not sufficiently improved.

  Samples (Examples 1-1 to 1-4 and Examples 2-1 to 2-4) to which the present invention was applied were prepared, and fatigue resistance and shape (uniformity) were evaluated. The results are shown in Tables 1 and 2 in comparison with the evaluations of the conventional example and Comparative Examples 1-1 to 1-4 and Comparative Examples 2-1 to 2-4.

  Example 1-1 is a steel cord having a 3 + 3 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned with each other in the longitudinal direction, the wire diameter is 0.25 mm, the twist pitch is 16 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 1.82, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 1-2 is a steel cord having a 3 + 3 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned with each other in the longitudinal direction, the wire diameter is 0.25 mm, the twist pitch is 16 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 2.20, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 1-3 is a steel cord having a 3 + 4 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.23 mm, the twist pitch is 14 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 1.75, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 1-4 is a steel cord having a 3 + 4 structure, in which all three strands of the core are substantially parallel to each other in the cord state, and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.23 mm, the twist pitch is 14 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 2.35, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 2-1 is a steel cord having a 4 + 4 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.28 mm, the twist pitch is 18 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 1.22, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 2-2 is a steel cord having a 4 + 4 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.28 mm, the twist pitch is 18 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 2.35, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 2-3 is a steel cord having a 4 + 5 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned with each other in the longitudinal direction, the wire diameter is 0.25 mm, the twist pitch is 16 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 1.16, which satisfies 1.1 ≦ d / D ≦ 2.4.

  Example 2-4 is a steel cord having a 4 + 5 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned with each other in the longitudinal direction, the wire diameter is 0.25 mm, the twist pitch is 16 mm, the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the strand The relationship of the diameter D is d / D = 2.38, which satisfies 1.1 ≦ d / D ≦ 2.4.

  In addition, the conventional example is a steel cord with a 2 + 2 structure, and the two core wires that are cores are substantially parallel and do not twist each other (aligned in one direction in the cord cross section), the wire diameter is 0.25 mm, and the twist pitch 14 mm, and the core wire has a gentle waveform due to the twist of the cord, and the relationship between the amplitude (apparent wave height of the core in the cord state) d and the strand diameter D is d / D = 0.3. It is.

  Comparative Example 1-1 is a steel cord having a 3 + 3 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the strand diameter is 0.25 mm, and the twist pitch is 16 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the cord state) d and the wire diameter D is d / D = 1.04, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 1-2 is a steel cord having a 3 + 3 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the strand diameter is 0.25 mm, and the twist pitch is 16 mm. However, the relationship between the amplitude of the core wire waveform (the apparent wave height of the core in the state of the cord) d and the wire diameter D is d / D = 2.46, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 1-3 is a steel cord having a 3 + 4 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.23 mm, and the twist pitch is 14 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the state of the cord) d and the wire diameter D is d / D = 1.06, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 1-4 is a steel cord having a 3 + 4 structure, in which all three strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.23 mm, and the twist pitch is 14 mm. However, the relationship between the amplitude of the core wire waveform (apparent wave height of the core in the cord state) d and the wire diameter D is d / D = 2.44, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 2-1 is a steel cord having a 4 + 4 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.28 mm, and the twist pitch is 18 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the state of the cord) d and the wire diameter D is d / D = 1.02, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 2-2 is a steel cord having a 4 + 4 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the wire diameter is 0.28 mm, and the twist pitch is 18 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the cord state) d and the wire diameter D is d / D = 2.45, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 2-3 is a steel cord having a 4 + 5 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the strand diameter is 0.25 mm, and the twist pitch is 16 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the state of the cord) d and the wire diameter D is d / D = 1.05, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  Comparative Example 2-4 is a steel cord having a 4 + 5 structure, in which all four strands of the core are substantially parallel to each other in the cord state and arranged in one direction (lateral direction) in a substantially straight line in the cord cross section. It has a waveform in which the phases are aligned in the longitudinal direction, the strand diameter is 0.25 mm, and the twist pitch is 16 mm. However, the relationship between the amplitude of the waveform of the core wire (the apparent wave height of the core in the cord state) d and the wire diameter D is d / D = 2.45, and 1.1 ≦ d / D ≦ 2. Does not satisfy 4.

  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 conventional example of 2 + 2 structure as 100.

  With respect to the shape (uniformity), the conventional example of the 2 + 2 structure was set as a reference (uniform), and the case of better shape was “uniform” and the case of not being “non-uniform”.

  From the evaluation results, the steel cords of Examples 1-1 to 1-4 and Examples 2-1 to 2-4, which are samples to which the present invention is applied, are the conventional examples and Comparative Examples 1-1 to 1-4 and It can be seen that the fatigue resistance is far superior to that of Comparative Example 2-4, and that the shape uniformity is also excellent.

It relates to an example of an embodiment of the present invention, (a) is a plan view of a steel cord, (b) is a side view of the steel cord, (c) is a sectional view of the steel cord. It is explanatory drawing which shows the waveform in the cord state of the strand of the core of the steel cord shown in FIG.

1, 2, 3 strands (core strands)
4, 5, 6 strands (side strands)
d Waveform amplitude D Wire diameter

Claims (1)

A steel cord of N + N structure or N + (N + 1) structure in which N or (N + 1) strands on the side are wound around a core composed of N (N = 3 to 4) strands,
The N core wires that are the cores are all parallel to each other and arranged in one direction substantially linearly in the cord cross section, and exhibit a waveform in which the phases are aligned in the cord longitudinal direction,
A steel cord for reinforcing rubber products, wherein the amplitude d of the waveform and the wire diameter D satisfy 1.1 ≦ d / D ≦ 2.4.