JPH08209566A - Steel cord for reinforcing rubber and its production - Google Patents

Abstract

PURPOSE: To provide a technique capable of enhancing the corrosion resistance and productivity of a steel cord used for reinforcing a rubber product. CONSTITUTION: In a flat open steel cord having a structure of 1×n (n is 2-5) and used for reinforcing rubber, the twisting pitch of the cord is >=55 times the diameter of an element wire, and when the steel cord is untwisted, the respective element wires have spiral shapes formed by the twisting, and deformed shapes different from the spiral shapes. The steel cord can be processed into a steel cord excellent in the penetration of rubbers thereinto and improved in corrosion resistance. Further, the productivity of the twisted wire can be improved, because the twisting pitch of the cord is >=55 times the diameter of the element wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a technique for improving the corrosion resistance and productivity of a steel cord used for reinforcing rubber products.

[0002]

2. Description of the Related Art In order to enhance the corrosion resistance of a steel cord having a 1 × n structure used for reinforcing rubber products, twisted open strands are formed so that there is a gap between adjacent strands of rubber. Structural steel cords are known. Further, at least one of the strands constituting the steel cord is provided with a bent portion and twisted so as to have a close-packed structure, and in this bent portion, there is a gap between adjacent strands, A steel cord in which rubber is allowed to enter the gap has also been proposed (JP-A-5-163687).

[0003]

In the former steel cord, since it has an open structure, that is, a twist structure having a gap between the steel cords, the steel cord has a slight There is a problem that it stretches even when a load is applied, and there is a problem in shape stability of rubber products. And an open structure style
In order to stabilize the properties of the rucode, the pitch of twisting must be 40 times or less the diameter of the strand, and there is a problem in the productivity of the strand. In the latter case, in the steel cord made of a wire provided with a bent portion, the properties of the cord are disturbed and the rubber is hard to enter unless the twisting pitch is 50 times or less the diameter of the wire. Become.

[0004]

The present invention was developed to overcome these drawbacks of conventional steel cords, the first of which is 1.times.n (n = 2-5). ) In a flat open steel cord having a structure, the twist pitch is 55 times or more the diameter of the strands, and when the strands of the steel cord are untwisted, each strand is twisted into a spiral shape. A rubber-reinforcing steel cord having a pattern and a habit different from this, preferably having a twist pitch of not more than 100 times the diameter of the wire.

[0005] The shape of the steel wire of the steel cord is a wavy shape or a spiral shape, and this wire has a tensile elongation of all the wires up to an elastic modulus of about 20,000 kgf / mm ^2. Different ones are effective.

A second aspect of the present invention is that two to five strands of wire are given different habits, and twisted by a twisting machine to form an open wire.
After being made into a puncode, the rollers at both ends have grooves and the remaining at least three rollers have a smooth surface, and the rollers are staggered to form a flattened shape. A rubber-reinforced steel cord with a flat cross section by passing through a device.
The present invention relates to a manufacturing method of a cord.

[0007]

The steel cord, which is formed by twisting a straight strand as described above with a twisted spiral type having an open structure and twisted at a twist pitch of 55 times or more the strand diameter, is If the binding force is weak and a slight pulling force is applied, the diameter of the steel cord cross section becomes small, and there is no gap between the strands, which prevents rubber from entering. In addition, if the side of an open-structure steel cord with a large twist pitch is pressed to increase the restraint of the wires, the gap between the wires is reduced during pressing, and the steel cord has good rubber penetration. Can't get

In the present invention, since all the strands constituting the steel cord are provided with a habit other than the twisted spiral type, the contact between the strands increases and the above problem occurs. It is now possible to prevent. The reason why the twist pitch is 55 times or more the strand diameter is to improve the productivity of the twisted wire. The larger the twist pitch, the more the productivity of the twisted wire is improved, but 100 times or more. When this is set, the restraint between the strands due to the twisted wire becomes poor, and the rubber penetration is deteriorated.

Since the purpose of giving a habit different from the spiral type for twisting is to increase the constraint between the strands,
The shape is not limited to a two-dimensional shape or a three-dimensional shape as long as the shape increases the constraint between the strands.

1 to 4 are conceptual sectional views of a steel code W of the present invention. FIG. 1 is a 1 × 3, FIG. 2 is a 1 × 4,
In FIG. 3, each 1 × 5 strand w is attached to the waveform. FIG. 4 is a similar sectional view of the 1 × 3 steel cord W in which the wire w is formed in a spiral shape.

FIG. 5 is a side view for explaining the patterning of the wire w when the twist of the steel cord W of the present invention is unraveled.
a ₁ represents the twisted pattern size (wave height), and b ₁ represents the peculiar size (wave height). Further, a ₂ indicates a twist pitch (wavelength), and b ₂ indicates a peculiar pitch (wavelength).

On the other hand, the strand obtained by unraveling the twist of the steel cord has a twisting habit for twisting, and in the tensile test of the strand, it has an elastic modulus depending on the material of the strand. Elongation due to the twisting tendency of the wire is observed up to about 20000 kgf / mm ² . In the present invention, the wire obtained by unraveling the twist of the steel cord is 1.2 kgf / mm ²
20,000 kgf / mm after applying the pre-tension load
^Since the elongation until the elastic modulus of ² is made different for all the strands that compose the steel cord, the contact between the strands is increased and the rubber penetration is improved. .

To impart a habit to the strands that is different from the twisting type, the strands may be passed between a pair of gears or passed through a pin type shaping device before being twisted. Become. Then, in order to make all of the strands have different elongations, changing the number of teeth and the amount of meshing of the gears,
Different habits can be created by adjusting the position of the pins.

FIGS. 6 and 7 are schematic views showing an apparatus for manufacturing a steel cord of the present invention, FIG. 6 shows a buncher twisting machine, and FIG. 7 shows a tuber twisting machine. In the figure, g ₁ ,
Reference numeral g ₂ is a pair of gears which are formed on the wire w, and h is a flattening device for flattening a steel cord twisted by a twisting machine.

In FIG. 6, 1 is a wire supply reel, 2 is a mold attaching device, 3 is a flyer bow, 4 is an overtwist device, 5
Is a take-up capstan, 6 is a traverser, and 7 is a take-up reel. A pair of gears g ₁ and g ₂ are wire supply reels.
Between the take-up capstan 5 and the traverser 6 while the flattening device h is arranged between the take-up capstan 5 and the traverser 6. Further, in FIG. 7, 8 is a tuber, 9 is a cabling die, and others are the same as in the case of FIG. The pair of gears g ₁ and g ₂ are the wire supply reel 1
And the tuber 8 and the flattening device h is arranged between the cabling die 9 and the take-up capstan 5.

FIG. 8 is a perspective view of an example of the flattening device. Grooves are formed in the rollers c at both ends at substantially the center thereof.
The remaining five rollers d have a smooth surface, and passing through each of these rollers causes flattening of the steel code.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, each data in the following comparative examples and examples
The data are as shown in Table 1. (Comparative Example 1) A wire for a steel cord having a carbon content of 0.82% by weight was drawn to have a diameter of 0.30 mm and a strength of 340.
A wire of kgf / mm ² was manufactured. The three strands were subjected to a twisting spiral die having a die-casting ratio of 150%, and then twisted to make a 1 × 3 open cord having a twist pitch of 18 mm. I made it. For this code, the buncher-twisting machine shown in FIG. 6 was used. Of course, the illustrated g
₁ and g ₂ were not used.

[0018] (Example 1) On the other hand, the wave height to wire w ₁ (b
₁ ) 0.43 mm, wavelength (b ₂ ) 2.7 mm, wire w
₂ , wave height (b ₁ ) 0.46 mm, wavelength (b ₂ ) 4 mm
Of the wire w ₃ has a wave height (b ₁ ) of 0.44 mm and a wavelength (b 1
₂ ) After applying a habit of 5.2 mm, each was twisted to prepare a 1 × 3 cord having a twist pitch of 18 mm, which was used as the steel cord of the present invention. In this example, the buncher-twisting machine shown in FIG. 6 was adopted.

The above-mentioned two types of cords were embedded in an unvulcanized rubber sheet and pressure-vulcanized, and the extent to which the rubber penetrated inside the cord was measured. It was presumed that almost 90% of the rubber was invaded by the invention cord, while the rubber of the comparative cord was infiltrated by only 60%, and it was estimated that the corrosion resistance was satisfactory.

(Comparative Example 2, Example 2) Further, the above two types of steel cords were flattened by the apparatus shown in FIG. Then, the extent to which the rubber penetrated inside the cord was examined by the above method, but the comparative cord had less restraint between the strands, so that the stranding of the strands became smaller and the rubber due to flattening was reduced. Invasion was only 65%, while the invention code was 1
00% rubber penetration was observed.

(Comparative Example 3 and Example 3) Further, in two types of steel cords similar to the above except that the twist pitch was 20 mm, rubber penetration into the inside of the cord Was 55% in the comparative code, while it was 90% in the invention code.

[0022]

[Table 1]

[0023]

EFFECTS OF THE INVENTION In the steel cord of the present invention, all the strands have a habit different from the twisted type, so that the penetration of the rubber into the steel cord is excellent and the corrosion resistance is high. It is an industrially useful invention that can improve the productivity of the twisted wire because the steel cord can be improved and the twist pitch is 55 times or more the diameter of the wire.

[Brief description of drawings]

FIG. 1 is a 1 × 3 steel wire having a wavy line.
It is sectional drawing of a rucod.

FIG. 2 is a 1 × 4 stylus in which the wires have a wavy shape.
It is sectional drawing of a rucod.

FIG. 3 is a 1 × 5 steel wire having a wavy line.
It is sectional drawing of a rucod.

FIG. 4 is a cross-sectional view of a 1 × 5 steel cord in which an element wire has a spiral shape.

FIG. 5 is a side view of the strand of the steel cord of the present invention when the twist is unraveled.

FIG. 6 is a buncher-twisting machine for manufacturing the steel cord of the present invention.

FIG. 7 shows a tuber twisting machine for producing the steel cord of the present invention.

FIG. 8 is a perspective view of a flattening device.

[Explanation of symbols]

W: Steel cord, w: Steel cord strand, a ₁・ ・ ・ Strand shape of the strand (wave height), a ₂・ ・ ・ Twist pitch (wavelength), b ₁・ ・ ・ Strength of strands (wave height), b ₂・ ・ ・ Pitch (wavelength), c, d ・ ・ ・ Roller of flattening device, g ₁ , g ₂・ ・ ・Gears, h ... Flattening device, 1 ... Strand supply reel, 2 ... Molding device, 3 ... Flyer bow, 4 ... Over twist device, 5 ... Receiving cap Stan, 6 ... traverser, 7 ... take-up reel, 8 ... tuber, 9 ... cabling die.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display part D07B 5/12

Claims (5)

[Claims] 1. In a flat open steel cord having a 1 × n (n = 2 to 5) structure, the twist pitch is 55 times or more the diameter of the wire, and the twist of the steel cord is released. A rubber-reinforced steel cord, wherein each strand has a spiral-shaped pattern formed by twisting and a different pattern. 2. A rubber-reinforced steel cord according to claim 1, wherein the twist pitch is 100 times or less the diameter of the strand. 3. The rubber reinforcing steel cord according to claim 1 or 2, wherein the peculiar shape, which is different from the twisted spiral shape, is a corrugated shape or a spiral shape. 4. The tensile elongation of the strands forming the steel cord until reaching the elastic modulus of about 20,000 kgf / mm ² is different in all the strands. A steel cord for rubber reinforcement as described. 5. Two to five strands are given different habits, and after twisted by a twisting machine to form an open cord, the rollers at both ends have grooves, The remaining at least three rolls have a smooth surface and these rolls are
A rubber-reinforced steel cord having a flat cross section by passing through a flattening device arranged in a staggered manner.