JPH11241282A - Steel cord and steel radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a steel cord having excellent fatigue resistance by using at least one wire not having a straight line portion of a flat surface and comprising only smoothly continuously curved portions, and to produce a steel radial tire having good durability. SOLUTION: This steel cord comprises a signal wire or twisted (1+N) (N is 2-12) wires which preferably comprise flat high tension steel wires having a carbon content of 0.07-1.00 wt.% Therein, at least one of the wires does not have a straight line portion on a flat surface, comprises only smoothly continuously curved portions, and is shaped in a two-dimensional wave form having a wave pitch 2-10 mm and a wave height of 0.02-10 mm. The steel cords are embedded in a rubber molded product in the form of belt plies or carcass plies to produced a steel radial tire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel cord used for reinforcing a rubber molded product such as a steel radial tire or a conveyor belt, and a vehicle radial tire using the steel cord.

[0002]

2. Description of the Related Art A stranded steel cord used for reinforcing a steel radial tire must be sufficiently filled with rubber up to the core. If there is a void that is not filled with rubber inside the steel cord, water penetrates there and corrodes the wire, and the corroded wire separates from the surrounding rubber. When the wire separates from the rubber, the wire moves around in the rubber due to vibration and deformation, and fretting wear occurs between the wires, so that the cord life is significantly shortened.

Therefore, conventional (N + M) twisting and (1+
N) In the case of a twisted steel cord (where M and N are integers), the rubber is penetrated into the cord core by corrugating at least one wire and increasing the distance between the corrugated wire and an adjacent wire. Improve the quality. Such corrugations (preforms) include a three-dimensional shape and a two-dimensional shape. The corrugation of the three-dimensional shape is described in, for example, FIG.
As shown in (a) and (b), a spiral wire 2S is formed using a spiral processing machine (spiral type preformer).

[0004]

However, since such a spiral corrugated wire 2S rises greatly from the other wire when twisted with another straight wire, it is difficult to maintain the shape of the entire cord, and the shape of the cord is lost. Easy to wake up.
Further, the spiral processing machine has a lower productivity than other types of preformers, and therefore has a higher manufacturing cost.

Conventional two-dimensional corrugation is performed, for example, using a gear crimping machine (gear crimp type preformer) as shown in FIGS. 11A and 11B. Wire 2K. However, since such a gear crimping wire 2K has an angular discontinuous shape in which the bent portions 3 and the linear portions 4 alternately appear, local stress concentration is likely to occur in the bent portion 3. For this reason, the gear crimp corrugated wire 2K has insufficient fatigue resistance and has a relatively short cord life.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a steel cord which is hardly deformed, has excellent fatigue resistance, and has a large elongation, and a steel radial tire using the same. And

[0007]

(1) A steel cord according to the present invention is a single-wire or 1 × N steel cord embedded and used in a rubber molded product, wherein at least one wire is used. It is characterized in that a two-dimensional corrugation consisting of only smoothly continuous curved portions not including a straight portion in one plane is provided.

(2) The steel cord according to the present invention comprises:
× N (where N is 2 to 12) steel cords, of which one or two wires are a combination of smoothly continuous arcs that do not include a straight portion in one plane. It is characterized by two-dimensional corrugation.

In a 1 × N twisted steel cord, the upper limit of N is set to 12 wires. The reason for this is that if N exceeds 12, twisting at once becomes unstable. That is, one core consisting of three core wires and nine peripheral wires
This is because twisting can be performed stably at a time up to × 12 steel cord, but twisting becomes unstable with 1 × 13 steel cord.

(3) The steel cord according to the present invention comprises:
A single-wire steel cord made of a book wire, characterized in that the wire is two-dimensionally corrugated consisting of a combination of smoothly continuous arcs that do not include a straight portion in one plane.

(4) Further, in the above (1), it is preferable that the corrugated pitch P is in the range of 2 to 10 mm and the corrugated height h is in the range of 0.02 to 10 mm. If the corrugated height h is less than 0.02 mm, the rubber hardly penetrates into the cord core. Also, the corrugated height h is 1
This is because if it exceeds 0 mm, the cord is likely to lose its shape.

(5) The corrugated wire is not limited to a round wire and may be flat.

(6) The steel radial tire according to the present invention is a cord having a single wire or 1 × N twist structure, wherein at least one wire has a smoothly continuous curved portion that does not include a straight portion in one plane. It is characterized in that a two-dimensional corrugated steel cord made of only steel is embedded in a rubber molded body as a belt ply or a carcass ply.

Since the steel cord of the present invention does not cause local stress concentration, the steel cord has better fatigue resistance than the conventional gear crimp corrugated cord. In addition, since the corrugation is formed in a two-dimensional shape, it does not easily collapse when twisted with another straight wire. Further, since the corrugation is a shape consisting of only a smooth continuous curve, the portability of the cord is increased, and the cord is greatly expanded.

The steel cord according to the present invention is manufactured as follows.

A special preformer having a large number of pins is used for corrugating. The wire is bitten between a pair of upper and lower large rollers, and the wire is alternately bent by a small-diameter pin. Since the small-diameter pin is arranged without a gap around the outer periphery of the large roller, the wire is continuously corrugated in an arc shape that is vertically inverted without generating a discontinuous portion. The diameter D of the pin needs to be sufficiently larger than the wire diameter d. If the diameter D of the pin is too small, the corrugated wire will not have a continuous arc shape but will have a bent portion or a straight portion. In order to prevent the wire from having a bent portion where local stress concentration is likely to occur, the diameter D of the pin should be equal to the wire diameter d.
Is preferably in the range of 5 to 50 times.

The two-dimensional corrugated shape includes, in addition to the combination curve of the continuous circular arcs, a sinusoidal curve, a cycloid (spiral curve) continuous arc, a cardioid (heart-shaped curve) continuous arc, A continuous arc of tractrics (suspended linear curve) may be employed. Further, a wire that has been three-dimensionally corrugated by a spiral processing machine may be flattened to change its shape from three-dimensional to two-dimensional.

Here, “corrugation (preform)” means
It means that the wire is plastically formed in advance by applying a stress higher than the elastic limit to the wire.

The constituent wire has a tensile strength of 280.
It is desirable to use a high-strength steel wire of up to 450 kgf / mm2. This is because, in order for the steel cord to obtain a desired breaking strength, the tensile strength of the wire needs to be 280 kgf / mm2 or more. On the other hand, if the tensile strength of the wire exceeds 450 kgf / mm2, the wire becomes brittle and the wire is likely to break.

The constituent wire has a carbon content of 0.7.
It is desirable to use a high-tensile steel wire of 0 to 1.00% by weight. This is because in order for the steel cord to obtain a desired breaking strength, the carbon content of the wire needs to be 0.70% by weight or more. On the other hand, if the carbon content of the wire exceeds 1.00% by weight, the wire becomes brittle and the wire is likely to break.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, three supply reels 5 are provided on the upstream side of the steel cord production line.
The round wire 2 is continuously fed from each reel 5 to the stranding machine 10 via the head plate 7 and the voice 8. For example, USP
A buncher-type twisted wire machine disclosed in JP-A-5-319915 or JP-A-9-31876 is used. Such a buncher type stranded wire machine 10 includes a plurality of turn rollers 11, a pair of fryers 12, and a cradle 13
, A capstan 14, and a winding drum 15.

A corrugating machine (preformer) 6 is provided between one supply reel 5 and the end plate 7 so that the corrugating machine 6 corrugates the wire 2 into a continuous arc shape. Has become.

As shown in FIGS. 2 and 3, a pair of upper and lower large rollers 62a, 62a,
62b are stored. The housing 61 has an entrance guide 65 and an exit guide 66. The wire 2 is introduced into the housing 61 via the entrance guide 65, passes between the large rollers 62 a and 62 b, and from the housing 61 via the exit guide 66. It is being sent out.

As shown in FIG. 4, the large rollers 62a, 62
The holders 67a and 67b are provided at equal pitches on the outer periphery of the holder b.
a and 63b are respectively attached. The pins 63a (63b) and 63a (63b) which are adjacent to each other are attached so that there is almost no gap.
The upper roller 62a is coaxially connected with the gear 64a, and the lower roller 62b is coaxially connected with the gear 64b. The upper and lower gears 64a, 64b mesh with each other. Double gear 6
The upper and lower rollers 62a and 62b are reliably rotated synchronously without causing slippage between the upper and lower rollers 62a and 62b due to 4a and 64b.

When the wire 2 is bitten between the large rollers 62a and 62b, it is bent by the pins 63a and 63b,
As shown in FIGS. 7 (b), 8 (b) and 9 (b), it is corrugated into a smoothly continuous arc shape. In this case, the diameter D of the pins 63a and 63b needs to be sufficiently larger than the wire diameter d. The diameter D of each of the pins 63a and 63b is preferably in the range of 5 to 50 times the wire diameter d.

Next, the flattening machine 70 will be described with reference to FIGS.

The flattening machine 70 flattens the round wire 2 into flat wires 2a, and has grooves 71a, 72a.
A pair of upper and lower rolling rolls 71 and 72 are provided.
The rolling rolls 71, 72 are mounted on shafts 73, 74, respectively, and the shafts 73, 74 are rotatably supported by blocks 73b, 74b via bearings 73a, 74a, respectively. A gear 76 is attached to the lower shaft 74,
This gear 76 meshes with a drive gear 774 of a motor 78. When the driving gear 77 is rotated by the motor 78, the rotational driving force is transmitted to the lower roll 72 via the gear 74. A jack bolt 75 is attached to the blocks 73b and 74b.
5, the distance between the upper and lower rolls 71 and 72 can be adjusted.

Table 1 shows sample numbers 1 to 15 (Examples 1 to 15).
6 and Comparative Examples 1 to 9) were also described for the configuration and various characteristics (performance) of the steel cords. Table 2 shows sample numbers 16 to 24 (Examples 7 to 12 and Comparative Examples 10 to 1).
The configuration and various characteristics (performance) of the steel cord of 2) were also compared and described. Cord configuration, wire shape, wire type, cord type, corrugated height, corrugated pitch,
The outer diameter of the cord and the unit weight of the cord are displayed.

The symbol LD in the table indicates the major axis of the flat wire, and the symbol SD indicates the minor axis of the flat wire. The flatness of the wire is a value obtained by dividing the short diameter by the long diameter (SD / L
D). Furthermore, the results of examining each item of the breaking load, breaking elongation, shochu fatigue (RF), and rubber permeability (RCPR) as various characteristics (performance) of the cord are displayed.

In Table 1, sample numbers 1 and 2
Nos. 4, 7 are round wire without corrugation (Comparative Examples 1, 3, 5)
Sample Nos. 10, 12, and 14 used flat wires without corrugation (Comparative Examples 7, 8, and 9), and Sample Nos.
8 is a round wire with a gear crimp wave (Comparative Example 2,
Sample Nos. 3, 6 and 9 are round wires (Examples 1, 2 and 3) each having an arc-shaped corrugated wire.
Numerals 1, 13, and 15 are intended for flat wires (Examples 4, 5, and 6) each having a corrugated shape. Also,
In Table 2, sample numbers 16, 19, and 22 correspond to twisted wire cords (Comparative Examples 10, 11, and 12) including round wires with gear crimping, and sample numbers 17, 20, and 2, respectively.
No. 3 shows a stranded wire cord (Examples 7, 9, 11) including a round wire with a corrugated arc, and sample numbers 18, 21, 24.
Are for stranded wire cords (Examples 8, 10, and 12) each including a flat wire corrugated with an arc.

Next, each embodiment and each comparative example will be described with reference to the drawings. [Examples 1, 2, 3] (Table 1) A round wire 2 having a tensile strength of 330 kgf / mm ² was obtained by using the preformer 6 shown in FIGS.
The continuous arc corrugated cord 2A shown in FIGS. The single wire cords 2A (sample numbers 3, 6, 9) of Examples 1, 2, and 3 have a diameter d1 of 0.25 mm, respectively.
0.30 mm and 0.35 mm, and the corrugated height h1 is 0.
239 mm, 0.352 mm, 0, 400 mm, and the corrugation pitch P1 is 3.330 mm, 3.319 mm, 3,
259 mm. The wires 2A of Examples 1, 2 and 3 had breaking strengths of 14.0 kgf and 20.0 kgf, respectively.
kgf and 24.2 kgf.

Further, the single wire cord 2 of each of the embodiments 1, 2, 3
A was embedded in a rubber member 81, respectively, to give a test piece 80 shown in FIGS. 27 and 28, which was used as a sample for a fatigue resistance test. Each of the fatigue resistance tests was evaluated using a belt durability tester 90 shown in FIG. As a result, the average value of the number of breaks (NBP) of each cord 2A was 16.8, 13.1 and 11.5, respectively. [Examples 4, 5, 6] (Table 1) FIGS. 16 (b), (c) and FIG. 25 (a) show a round wire 2 having a tensile strength of 330 kgf / mm ² using the apparatus shown in FIG. 16 (a). ) And (b) shown in FIG. Single wire cord 2C of each of Examples 4, 5, and 6
(Sample Nos. 11, 13, and 15) each have a long diameter W
3 (LD) is 0.27mm, 0.32mm, 0.37m
m, the minor axis D3 (SD) is 0.22 mm, 0.26 m
m, 0.31mm, corrugated height F3 is 0.234m
m, 0.362 mm, 0.387 mm, and corrugation pitch P3 is 3.299 mm, 3.291 mm, 3.288 m
m. In addition, the single wire cord 2C of each of the embodiments 4, 5, and 6
Has a breaking strength of 13.9 kgf and 20.6 kg, respectively.
f, 24.7 kgf.

Further, the single wire cord 2 of each of the embodiments 4, 5, and 6
C was embedded in a rubber member 81, respectively, to obtain a test piece 80 shown in FIGS. 27 and 28, which was used as a sample for a fatigue resistance test. Number of breaks of each cord 2C (NB
The average values of P) were 21.3 and 15.3, respectively.
It was 14.6 places. [Comparative Examples 1, 3, 5] (Table 1) Round wire 2 with a tensile strength of 330 kgf / mm ² class
(No corrugations) were taken as Comparative Examples 1, 3, and 5. Round wire 2 of each of Comparative Examples 1, 3, and 5 (sample numbers 1, 4, and 7)
Have diameters d of 0.25 mm, 0.30 mm, 0.
35 mm and breaking strength of 15.5 kgf, 22.7
kgf and 27.5 kgf.

Further, the wires 2 of Comparative Examples 1, 3, and 5 were embedded in rubber members 81, respectively, as shown in FIGS.
The test piece 80 shown in FIG. 8 was used as a sample for a fatigue resistance test. The average value of the number of breaks (NBP) of each wire 2 was 16.0, 11.2, 10.0, respectively.
It was a place. [Comparative Examples 2, 4, and 6] (Table 1) The tensile strength was 330 using a general-purpose gear crimping machine.
kgf / mm ² class round wire 2 is crimped,
The single-wire cords (not shown) of Comparative Examples 2, 4, and 6 were used. Single line code of each of Comparative Examples 2, 4, and 6 (sample numbers 2, 3,
8) means that the diameter d is 0.25 mm, 0.30 mm,
0.35 mm and the corrugated height h is 0.244 mm, 0,
363 mm, 0.421 mm, and the corrugation pitch P is 3,
204 mm, 3,169 mm, and 3,180 mm.
The single wire cords of Comparative Examples 2, 4, and 6 had breaking strengths of 13.4 kgf, 19.0 kgf, and 22.8 k, respectively.
gf.

Further, the single-wire cords of Comparative Examples 2, 4, and 6 were embedded in rubber members 81, respectively, to obtain test pieces 80 shown in FIGS. 27 and 28, which were used as samples for a fatigue resistance test. The average value of the number of break points (NBP) of each cord was 27.6, 22.7, and 21.3, respectively.
It was a place. [Comparative Examples 7, 8, 9] (Table 1) Flat wire 2C having a tensile strength of 330 kgf / mm ² class
(No corrugations) were taken as Comparative Examples 7, 8, and 9. The flat wire 2C of each of Comparative Examples 7, 8, and 9 (sample numbers 10, 1)
No. 2, 14) has the same cross section as that of the above Examples 4, 5, and 6. Wire 2C of each of Comparative Examples 7, 8, and 9
Has a breaking strength of 14.7 kgf and 21.7 kg, respectively.
f, 26.1 kgf.

Further, the wires 2C of Comparative Examples 7, 8, and 9 were embedded in rubber members 81, respectively, to obtain test pieces 80 shown in FIGS. 27 and 28, which were used as samples for a fatigue resistance test. Number of break points of each wire 2C (NBP)
Are 18.2, 13.4 and 1 respectively.
It was 3.0 places. [Examples 7, 9, 11] (Table 2) Three round wires having a tensile strength of 330 kgf / mm ² were simultaneously fed to the apparatus shown in FIG. 1, and one of the wires was continuously arcuated. This continuous arc waved wire 2
A is twisted with the other two wires 2 to form a wire 1 shown in FIG.
A steel cord 3 having a × 3 (with one circular wave) twist structure was manufactured. The steel cords 3 (sample Nos. 17, 20, and 23) of Examples 7, 9, and 11 have diameters d1 of 0.27 mm, 0.27 mm, and 0.27 mm, respectively, and a corrugated height h1 of 0.30 mm. 0.33mm, 0.320m
m, the corrugated pitch P1 is 3.20 mm, 3.28 m
m, 3.30 mm. In addition, each of the embodiments 7, 9, 11
Has a unit weight of 1,340 g / m,
1,785 g / m and 2,233 g / m.

Further, the stranded wire cords 3 of Examples 7, 9, and 11 are embedded in rubber members 81, respectively, as shown in FIG.
A test piece 80 shown in FIG. 28 was used as a sample for a fatigue resistance test. The average value of the number of break points (NBP) of each of Examples 7, 9, and 11 was 3.0 and 0.8, respectively.
And 0.2 places. In addition, rubber permeability (RCP
As a result of examining R), the values were 95%, 95%, and 95% for the stranded wire cords 3 of 7, 9, and 11, respectively. [Examples 8, 10, 12] (Table 2) A round wire having a tensile strength of 330 kgf / mm ² was flattened by the device shown in FIG. , (B) was used as a flat wire 2C with a continuous arc wave. This continuous circular corrugated flat wire 2C is twisted with the other two round wire wires 2 and
The steel cord 3G having a 1 × 3 (1 circular wave corrugated flat wire) stranded structure shown in FIG. Examples 8, 10, 12
Each of the flat wires 2C of continuous arc corrugations (sample numbers 18, 21, 24) has a major axis W3 (LD) of 0.29.
mm, 0.29 mm, 0.29 mm and the minor diameter D3 (S
D) is 0.24mm, 0.24mm, 0.24mm,
Corrugation height F3 is 0.28mm, 0.31mm, 0.3
1 mm, the corrugated pitch P3 is 3.33 mm, 3.33
mm and 3.33 mm. In addition, each of Examples 8 and 1
The codes 3G of 0 and 12 each have a unit weight of 1.34.
0 g / m, 1.784 g / m, 2.234 g / m, breaking strength 53.3 kgf, 72.1 kgf, 89.3 k
gf.

Further, the stranded wire cords 3G of Examples 8, 10, and 12 were embedded in rubber members 81, respectively, to obtain test pieces 80 shown in FIGS. 27 and 28, which were used as samples for a fatigue resistance test. did. The average value of the number of break points (NBP) of each of Examples 8, 10, and 12 was 2.0, respectively.
There were 0.5 spots and 0.2 spots.

Furthermore, as a result of examining the rubber permeability (RCPR), the stranded wire cord 3G of each of Examples 8, 10, and 12 was used.
Were 95%, 100%, and 95%. [Comparative Examples 10, 11, 12] (Table 2) The tensile strength was 330 using a general-purpose gear crimping machine.
The kgf / mm ² grade round wire wire was attached crimped waves.
A crimped corrugated wire is twisted together with the other two round wires 2 by a general-purpose puncher-type twisted wire machine, and a 1 × 3 (1-gear crimped corrugated wire) twisted steal cord of Comparative Examples 10, 11, and 12 is used. (Not shown). The codes (sample numbers 16, 19, and 22) of Comparative Examples 10, 11, and 12 have a diameter d of 0.27 mm, respectively.
0.27mm, 0.27mm, height of corrugation h is 0.2
They are 9 mm, 0.29 mm, and 0.25 mm, and the corrugated pitch P is 3.37 mm, 3.31 mm, and 3.36 mm. The cords of Comparative Examples 10, 11, and 12 have unit weights of 1.339 g / m and 1.784 g / m, respectively.
2.234 g / m, breaking strength 52.5 kgf, 7
It was 1.0 kgf and 88.0 kgf.

Further, the cords of Comparative Examples 10, 11, and 12 were embedded in rubber members 81, respectively, to obtain test pieces 80 shown in FIGS. 27 and 28, which were used as samples for a fatigue resistance test. The average value of the number of break points (NBP) of each of Comparative Examples 10, 11, and 12 was 6.4, 2.2, respectively.
And 0.6 places. In addition, rubber permeability (RCP
As a result of examining R), it was found to be 95%, 93%, and 83% for the codes of Examples 10, 11, and 12, respectively. [Evaluation of Fatigue Resistance] The fatigue resistance of each steel cord was evaluated using a test piece 80 shown in FIGS. 27 and 28 by a belt durability tester 90 shown in FIG. The test piece 80 has five steel cords 2 (2A, 2A)
B, 2C, 2D, 3, 3F, 3G, 3H) are buried in a line at equal pitch intervals to form a sample layer, and a stranded wire cord 83 having a 2 + 2 × 0.25 configuration is provided on the back side of the rubber member 81 at five pitches. It is embedded evenly in a line at intervals, and this is used as the spine eyebrows. Incidentally, the dimensions of each part of the test piece 80 are such that the thickness T is 6 mm, the width W is 12 mm, and the length L3 is 400 mm.

The belt durability tester 90 has a roller 91, and its diameter is 20 mm. A test piece 80 is wound around the roller 91 so that the sample layer in which the single-wire steel cord 2A is embedded is on the abdominal side (inside), and weights 92 are attached to both ends, respectively, and a load of 60 kgf is applied to the test piece 80. I did it. The stroke of the test piece 80 was set to 50 mm, the direction was switched at a cycle of 60 times per minute, and this was repeated 2000 times.

After completion of the test, the sample layer of the test piece 80 was irradiated with soft X-rays to take an X-ray transmission photograph. Observing the X-ray radiograph, the number of breaks (NB
P) was counted for each sample. As for the number of tests, five lots were regarded as one lot, and the average value was entered in the numerical value columns of Tables 1 and 2, respectively. Further, the fatigue resistance of the comparative example cord without corrugation was defined as a reference value of 100%, and the ratio to this was entered in the column of percentage in Tables 1 and 2, respectively. As is clear from Table 1, Examples 1, 2, 3, 4, 5, and 6 exhibited higher fatigue resistance than Comparative Examples 2, 4, and 6. Further, as is apparent from Table 2, Examples 7, 8, 9, 10, 1
Samples Nos. 1 and 12 had higher fatigue resistance than Comparative Examples 10, 11 and 12. It was also found that the longer the corrugated pitch P and the lower the corrugated height h, the better the fatigue resistance of the steel cord. [Evaluation of Rubber Permeability] Stranded Steel Cord (Example 7)
-12 and Comparative Examples 10-12) were evaluated for rubber permeability. As is clear from Table 2, the rubber permeability of Examples 7 to 12 was comparable to that of Comparative Examples 10 to 12.

Next, various steel radial tires and a method of manufacturing the same will be described with reference to FIGS. [First Tire] The single-wire steel cords 2A are sandwiched between green sheets (raw rubber sheets) so that the intervals between the single-wire steel cords 2A are substantially constant. After calendering, the sheet is cut into a predetermined size. In the case of a tire belt layer, the cord 2A is cut so as to be oblique to the four sides of the sheet, a plurality of cut sheets 24A are wound around the outer periphery of the tire, and a rubber for the outermost layer is formed on which a tread 28 is formed. The sheet 26 is attached. Steel cord 2
The composite comprising A and rubber is heated and pressurized to finally form a tire having a desired shape. As a result, FIG.
The steel radial tire 20A having the tire belt layer 24A shown in FIG. [Second Tire] A high-tensile steel wire having a carbon content of 0.70 to 1.00% by weight is prepared (Step S1), quenched under predetermined conditions (Step S2), and plated with a Cu—Zn alloy. (Step S3). Furthermore, the plated steel wire was drawn to finally obtain a round wire 2 having a tensile strength of 330 kgf / mm2 class (step S4). The round wire 2 is subjected to continuous arc corrugation by the apparatus shown in FIG. 12A (step S5), and further flattened (step S6), and the single-wire steel cord 2B is wound around a winder 9. Code 2B has a major axis W2 of 0.37
mm, the minor axis D2 is 0.31 mm, and the corrugated height F2 is 0.3 mm.
The corrugation pitch P is 3288 mm (see FIG. 20). The cord 2B is sandwiched between green sheets (raw rubber sheets) such that the interval between the cords 2B is substantially constant (step S7). In the calendering step S7, the cords 2B are arranged so that the corrugations are in the thickness direction of the rubber sheet. The cord 2B is cut so as to be oblique with respect to the four sides of the rubber sheet (step S8), a plurality of cut sheets 24B are wound around the outer periphery of the tire, and a rubber sheet 26 for the outermost layer, on which a tread 28 is formed, is wound thereon.
(Step S9). The composite made of the steel cord 2A and the rubber is heated and pressed to finally form a tire having a desired shape (step S10). As a result, FIG.
A steel radial tire 20B having the tire belt layer 24B shown in (b) was obtained. [Third Tire] A high-tensile steel wire having a carbon content of 0.70 to 1.00% by weight is prepared (Step S21), and quenched under predetermined conditions (Step S22), and Cu—Zn alloy plating is performed. (Step S23). Further, the plated steel wire was drawn to finally obtain a round wire 2 having a tensile strength of 330 kgf / mm2 class (step S24).

The round wire 2 is flattened by the apparatus shown in FIG. 16A (step S 25), and is further subjected to continuous arc wave formation (step S 26). The flat wire 2 C with continuous arc wave is wound around the winding machine 9. The wire 2C has a long diameter W3 of 0.3
7 mm, the minor diameter D3 is 0.31 mm, the corrugated height F3 is 0.387 mm, and the corrugated pitch P3 is 3.288 mm (see FIG. 25).

Next, the flat wires 2C, 2C
The round wire 2 was twisted with the buncher-type twisting machine 10 to obtain a steel cord 3G having a 1 × 3 twist structure shown in FIG. 21 (step S27). Code 2C and Code 2
The cord 2C is sandwiched between green sheets (raw rubber sheets) so that the distance between the cords 2C is substantially constant (step S2).
8). In the calendering step S28, the cords 2C are arranged so that the corrugations are in the thickness direction of the rubber sheet. Next, the cord 2C is cut so as to be oblique to the four sides of the rubber sheet (step S29), and a plurality of cut sheets 24 are cut.
C is wound around the outer circumference of the tire, and an outermost layer rubber sheet 26 forming a tread 28 is attached thereon (step S).
30). The composite made of the steel cord 2C and rubber is heated and pressed to finally form a tire having a desired shape (step S31). As a result, a steel radial tire 20C having a tire belt layer 24C shown in FIG.
was gotten. [Fourth tire] A high-tensile steel wire having a carbon content of 0.70 to 1.00% by weight is prepared (Step S41), and quenched under predetermined conditions (Step S42), and Cu—Zn alloy plating is performed. (Step S43). Further, the plated steel wire was drawn to finally obtain a round wire 2 having a tensile strength of 330 kgf / mm2 class (step S44). This round wire 2 is shown in FIG.
A, a first continuous arc wave is applied in the major axis direction (step S45), flattening (step S46), and a second continuous arc wave is applied in the minor axis direction (step S47). The flat steel cord 2 </ b> D with the first and second continuous arc waves is wound around the winder 9. The cord 2D has a major axis W4 of 0.37 mm, a minor axis D4 of 0.31 mm, a first corrugation height F4 of 0.366 mm, a second corrugation height F5 of 0.322 mm, and a corrugation pitch P4. 3.291 mm,
The corrugation pitch P5 is 3.291 mm (see FIG. 26).

The cord 2D is sandwiched between green sheets (raw rubber sheets) so that the intervals between the cords 2D are substantially constant (step S48). In the calendering step S48, the cords 2D are arranged such that the minor axis is in the thickness direction of the rubber sheet. Next, the cord 2D is cut so as to be inclined with respect to the four sides of the rubber sheet (step S4).
9) A plurality of cut sheets 24D are wound around the outer periphery of the tire, and the outermost layer rubber sheet 26 forming the tread 28 is stuck thereon (step S50).

The composite made of the steel cord 2D and rubber is heated and pressed to finally form a tire having a desired shape (step S51). As a result, the steel radial tire 2 having the tire belt layer 24D shown in FIG.
0D was obtained. [Fifth Tire] A steel sheet 3 having a 1 × 3 twisted structure (a circular wire with a circular arc) shown in FIG. 8 and a green sheet (raw rubber sheet) such that the interval between the cords 3 is substantially constant. Between the two. Next, the sheet is cut into a predetermined size. In the case of a tire belt layer, the cord 3 is cut so as to be oblique to the four sides of the sheet,
Wrap a plurality of cutting sheets 24E around the outer circumference of the tire,
Outermost layer rubber sheet 2 on which tread 28 is formed
Attach 6.

The composite comprising the steel cord 3 and the rubber is heated and pressed to finally form a tire having a desired shape. As a result, the tire belt layer 24 shown in FIG.
The steel radial tire 20E having E was obtained. [Sixth Tire] A steel cord 3F having a 1 × 3 twisted structure (a flat wire with a circular arc) shown in FIG.
It is sandwiched between green sheets (raw rubber sheets) so that the interval between F and the cord 3F is substantially constant. Next, the sheet is cut into a predetermined size. In the case of a tire belt layer, the cord 3F is cut so as to be oblique to the four sides of the sheet, a plurality of cut sheets 24F are wound around the outer periphery of the tire, and the outermost layer rubber sheet on which a tread 28 is formed is formed. Attach 26.

The composite made of the steel cord 3F and rubber is heated and pressed to finally form a tire having a desired shape. As a result, the tire belt layer 2 shown in FIG.
A steel radial tire 20F having 4F was obtained. [Seventh tire] A steel cord 3G having a 1 × 3 twisted structure (a flat wire with a circular arc) shown in FIG.
It is sandwiched between green sheets (raw rubber sheets) so that the gap between G and the cord 3G is substantially constant. Next, the sheet is cut into a predetermined size. In the case of a tire belt layer, the cord 3G is cut so as to be oblique to the four sides of the sheet, and a plurality of cut sheets 24G are wound around the outer periphery of the tire, and the outermost rubber sheet on which the tread 28 is formed is formed. Attach 26.

The composite made of the steel cord 3G and rubber is heated and pressed to finally form a tire having a desired shape. As a result, the tire belt layer 2 shown in FIG.
A 20G steel radial tire having 4G was obtained. [Eighth tire] A steel cord 3H having a 1 × 3 twisted structure (a flat wire with a circular arc) shown in FIG.
It is sandwiched between green sheets (raw rubber sheets) so that the distance between H and the cord 3H is substantially constant. Next, the sheet is cut into a predetermined size. When the tire belt layer is used, the cord 3H is cut so as to be oblique to the four sides of the sheet, and a plurality of cut sheets 24H are wound around the outer periphery of the tire, and an outermost rubber sheet is formed on which a tread 28 is formed. Attach 26.

The composite made of the steel cord 3H and rubber is heated and pressed to finally form a tire having a desired shape. As a result, the tire belt layer 2 shown in FIG.
A steel radial tire 20H having 4H was obtained.

In the above embodiment, the case where the steel cord of the present invention is used as a belt ply of a tire has been described. However, the present invention is not limited to this, and the steel cord of the present invention can be used as a carcass ply of a tire. Is also good.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

According to the present invention, it is possible to provide a steel cord having better fatigue resistance than the conventional two-dimensional gear crimp corrugated cord.

Further, according to the present invention, it is possible to provide a steel cord which is less likely to lose its shape than a conventional three-dimensional spiral corrugated cord.

Further, according to the present invention, it is possible to provide a steel radial tire having higher durability than conventional products.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a steel cord manufacturing apparatus.

FIG. 2 is a front view showing an outline of a preformer (a special crimping machine for continuous arc wave forming) used for manufacturing a steel cord according to the present invention.

FIG. 3 is a side view of the preformer shown in FIG. 2;

FIG. 4 is a partially enlarged view showing a main part of the preformer shown in FIG. 2;

FIG. 5 (a) is an enlarged view showing a part of a steel cord (a single-wire steel cord subjected to continuous arc corrugation) according to the embodiment of the present invention, and FIG. 5 (b) is a steel according to the embodiment of the present invention. It is a cross-sectional view of a cord.

FIG. 6 is a cross-sectional view of a steel cord (a stranded wire steel cord subjected to continuous arc corrugation) according to the embodiment of the present invention.

FIG. 7A is a schematic external view of a conventional gear crimp corrugated cord (single-wire steel cord; 0.25HT).
(B) is an external appearance schematic diagram of an arc-corrugated cord (single-wire steel cord; 0.25HT) of the present invention.

FIG. 8A is a schematic external view of a conventional gear crimp corrugated cord (single-wire steel cord; 0.30HT);
(B) is an external appearance schematic diagram of an arc-corrugated cord (single-wire steel cord; 0.30HT) of the present invention.

FIG. 9A is a schematic external view of a conventional gear crimp corrugated cord (single-wire steel cord; 0.35HT).
(B) is an external appearance schematic diagram of the arc-corrugated cord (single-wire steel cord; 0.35HT) of the present invention.

10A is a front view schematically illustrating a conventional three-dimensional (spiral) corrugated wire, and FIG. 10B is a schematic diagram schematically illustrating the conventional three-dimensional (spiral) corrugated wire. It is sectional drawing.

11A is a front view schematically illustrating a conventional two-dimensional (gear crimp) corrugated wire, and FIG. 11B is a schematic view schematically illustrating a conventional two-dimensional (gear crimp) corrugated wire. It is sectional drawing.

FIG. 12A is a conceptual diagram schematically illustrating an outline of a production line for producing a steel cord according to an embodiment of the present invention, and FIG. 12B is a conceptual diagram illustrating a change in a wire external shape. FIG. 3C is a conceptual diagram showing a change in the wire cross-sectional shape.

FIG. 13 is a view showing a roll rolling device for flattening a wire.

FIG. 14 is a view of the roll rolling apparatus of FIG. 13 as viewed from a wire pass line direction.

FIG. 15 is a flowchart illustrating a method for manufacturing a steel radial tire according to an embodiment of the present invention.

FIG. 16A is a conceptual diagram schematically showing an outline of a production line for producing a steel cord according to an embodiment of the present invention, and FIG. 16B is a conceptual diagram showing a change in the wire external shape. FIG. 3C is a conceptual diagram showing a change in a wire cross-sectional shape.

FIG. 17 is a flowchart illustrating a method for manufacturing a steel radial tire according to another embodiment of the present invention.

FIG. 18A is a conceptual diagram schematically showing an outline of a production line for producing a steel cord according to another embodiment of the present invention, and FIG. 18B is a conceptual diagram showing a change in the wire external shape. It is a figure and (c) is a key map showing change of a wire section shape.

FIG. 19 is a flowchart illustrating a method for manufacturing a steel radial tire according to another embodiment of the present invention.

FIG. 20 is a cross-sectional view showing a steel cord (a stranded steel cord) according to the embodiment of the present invention.

FIG. 21 is a cross-sectional view showing a steel cord (a stranded steel cord) according to the embodiment of the present invention.

FIG. 22 is a cross-sectional view showing a steel cord (a stranded steel cord) according to the embodiment of the present invention.

23 (a), (b), (c), and (d) are cross-sectional views each showing a part of a steel radial tire according to an embodiment of the present invention.

24 (e), (f), (g) and (h) are cross-sectional views each showing a part of the steel radial tire according to the embodiment of the present invention.

FIG. 25 (a) is a cross-sectional view showing a steel cord (flat single-wire steel cord) according to another embodiment of the present invention, and FIG. 25 (b) is a schematic external view showing a steel cord of another embodiment. is there.

FIG. 26A is a cross-sectional view showing a steel cord (flat single-wire steel cord) according to another embodiment of the present invention, and FIG. 26B is a schematic external view showing a steel cord of another embodiment. is there.

FIG. 27 is a perspective view showing a belt durability test piece.

FIG. 28 is a cross-sectional view of a belt durability test piece.

FIG. 29 is a schematic diagram of a belt durability tester.

[Explanation of symbols]

2 ... wire (elementary wire), 2A, 2B, 2C, 2D ... arc-corrugated single wire cord, 2K ... gear crimp single wire cord (two-dimensional corrugated wire), 2S ... spiral single wire cord (three-dimensional corrugated wire), 3, 3E, 3F, 3G, 3H: Arc-cored stranded wire cord, 20A, 20B, 20C, 20D, 20E, 20F, 2
0G, 20H: Steel radial tire, 7: End plate, 8: Voice (die), 10: Stranding wire machine, 6: Corrugating machine, 61: Housing, 62a, 62b
... Large roller, 63a, 63b ... Pin, 64a, 64b ... Shaft, 65,6
6: Guide, 67a, 67b: Holder, 70: Flattening machine.

Claims (10)

[Claims] 1. A steel cord having a single wire or a 1 × N structure embedded and used in a rubber molded body, wherein at least one wire has a smoothly continuous curve that does not include a straight portion in one plane. A steel cord characterized by a two-dimensional corrugation consisting only of parts. 2. A steel cord having a 1 × N (where N is 2 to 12) twisted structure, wherein one or two of them are used.
A steel cord characterized in that a book wire is two-dimensionally corrugated consisting of a combination of smoothly continuous arcs that do not include a linear portion in one plane. 3. A single-wire steel cord made of one wire, the wire being two-dimensional corrugated consisting of a combination of smoothly continuous circular arcs that do not include a straight portion in one plane. Characterized by steel cord. 4. A corrugated pitch P of 2 to 10 mm
The steel cord according to any one of claims 1 to 3, wherein the corrugated height h is in a range of 0.02 to 10 mm. 5. The steel cord according to claim 1, wherein the corrugated wire is flat. 6. A steel cord having a single wire or a 1 × N twist structure, wherein at least one wire has a two-dimensional corrugation consisting only of smoothly continuous curved portions not including straight portions in one plane. A steel radial tire comprising a steel cord embedded in a rubber molded body as a belt ply or a carcass ply. 7. A steel cord having a 1 × N (where N is 2 to 12) twisted structure, wherein one or two of the wires have a smooth shape including no straight portion in one plane. A steel radial tire having a two-dimensional corrugated steel cord composed of a combination of continuous arcs embedded in a rubber molded body as a belt ply or a carcass ply. 8. A steel cord having a two-dimensional corrugation comprising a combination of smoothly continuous circular arcs each of which has no straight portion in one plane, wherein the steel cord is a single-wire steel cord. A steel radial tire characterized by being embedded in a rubber molding as a carcass ply. 9. The corrugated pitch P of the steel cord is in the range of 2 to 10 mm, and the corrugated height h is 0.1 mm.
7. The range of from 02 to 10 mm.
9. The steel radial tire according to any one of items 1 to 8. 10. The steel radial tire according to claim 6, wherein the corrugated wire is flat.