JPH07166485A - Production of metal cord and apparatus therefor - Google Patents

Abstract

PURPOSE:To obtain a metal cord having required initial elongation and formability necessary as a metal cord, especially a steel tire cord for automobile. CONSTITUTION:This metal cord is produced by twisting plural metal strands together, clamping a part of the twisted cord and applying a rotation to the twisted cord in a direction same or reverse to the twisting direction. The initial elongation and formability of the metal cord can be adjusted by the application of rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of steel tire cords used for reinforcing radial tires for automobiles and metal cords used for general industrial ropes.

[0002]

2. Description of the Related Art As a metal cord, as shown in FIG. 4 (a), four metal wires 1 are twisted together to form a metal strand 2.
The metal cord 3 is typically formed by forming 7 cords and twisting 7 more.

And as a method of manufacturing this metal cord,
A method using a tubular twisting machine as shown in FIG. 5 is well known.

The machine winds a plurality of metal strands 2 around a bobbin 4 as shown in the figure and attaches it to a rotating supply device 5 to supply it. The center of each of the plurality of metal strands 2 goes straight as it is, and the other metal strands 2 are preformed through the modeled portion 6 and twisted at the gathering portion 7.

The twisted wires pass through a straightening device 8 for ironing by a plurality of rollers and are wound up by a winding device 9 to complete a metal cord 3.

[0006]

Now, taking steel tire cords, which are important uses of metal cords, as examples, the quality requirements for metal cords have become extremely severe with the improvement of tire quality in recent years. In particular, the twisting of cords from the viewpoint of compatibility as a composite of cords and rubber, such as the uniformity of rubber entry inside the cords (between strands) in tires (in rubber) and the uniformity of cord spacing during cord arrangement. Matching stability is becoming very important.

[0007] As an index for the stability of twisting, the shaping ratios described in the "Wire Rope Handbook" (published on October 15, 1942 by Chira Shobo) and the initial values used in the steel tire cord industry Elongation (tightness),
It has moldability (flexibility).

On the other hand, in the tubular type twisting machine, the tension control of the metal strands constituting the metal cords is performed by the supply device 5, and the spiral deformation process (preform) is applied to the metal strands. The adjustment of residual torsion and straightness (test items described in JIS G 3510) is performed only by the straightening device 8 which removes residual stress by ironing the twisted wires with a plurality of rollers. Absent.

Therefore, since the shaping section 6 is constructed as shown in FIG. 4B, the degree of the preform, that is, the shaping rate can be adjusted by adjusting the position of the shaping pin 10. However, there is a problem in that the initial elongation and the formability cannot be adjusted arbitrarily to a predetermined twisted state because there is no adjusting device that directly acts.

[0010]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and its purpose is to improve the initial elongation and formability without affecting the adjustment of residual torsion and straightness. It is an object of the present invention to provide a method and a device that can be arbitrarily adjusted.

The first feature of the present invention is that a twisted wire is twisted by twisting the twisted wire in the same direction as the twisted wire by holding a part of the twisted wire or in the opposite direction. ) Or untwisting (untwisting) to change the tightness of the twisted wire and adjust the initial elongation and formability.

The second feature is that the twisting and untwisting are performed by giving a rotation speed of 1.2 to 15.0%, preferably 1.5 to 10.0% of the cord twisting rotation speed.

The third feature is that the rotation of the twisted wire is
The wire is gripped by a plurality of rollers, and the support base of the gripping roller is rotated in the same direction as the twisting direction or in the opposite direction.

[0014]

In FIG. 1, reference numeral 3 denotes a metal cord which is twisted by the twisting portion 7 and is sent in the direction of the straightening device 8 as shown by the arrow A. And the rotation is given. The arrow B corresponds to the twisting direction in the rotation direction.

Although the gripping method will be described later, the gripping suppresses and fixes rotation of the metal cord in the circumferential direction (residual torsion) caused by residual strain after twisting of the metal wires constituting the metal cord, Further, in that state, by twisting or untwisting the metal cord, the whole is rotated from the grip portion.
By this addition, the degree of tightness of the metal wire forming the metal cord is changed, and thereby the initial elongation and the formability are adjusted.

By rotating in the direction B shown in the drawing, the twisting is performed between the inlet side of the metal cord 3, that is, between the twisting portion 7 and the adjusting device 11, and the twisting is performed between the outlet side, that is, between the adjusting device 11 and the straightening device 8. Will be. In this way, once twisted at the inlet side, untwisted at the outlet side,
The double twist effect is produced, and the cord that is untwisted and fed is adjusted to a stable loose twist.

When the rotation is in the opposite direction to B, that is, in the twisting direction, the twisting conditions on the inlet side and the outlet side are opposite to those described above, and the metal cord fed from the outlet side is twisted and stabilized. It will be adjusted to the one that has disappeared.

Therefore, the initial elongation increases as the gap between the metal wires forming the cord increases, and the elongation increases. Therefore, the twist of the cord is tightened and reduced by selecting the rotation direction of the adjusting device. By loosening, it can be adjusted freely as much as possible.

The formability is determined by the frictional resistance between the metal wires forming the cord and the shape retention. Therefore, when the metal cord is tightened, the frictional resistance is increased and it is difficult to return to the deformation received. Therefore, the metal cord can be tightened to reduce the size, and the metal cord can be increased to increase the size.

The rotation of this adjusting device causes residual strain in the metal cord, but if the rotation speed is within the range of 1.2 to 15% of the twisting rotation speed of the metal cord, the conventional straightening device 8 is allowed to pass. It is fully adjustable. Further, as for the finish of the metal cord, if there is no restriction on the residual torsion, there is no concern about the rotation speed, and the adjusting device can be provided between the straightening device and the winding device.

[0021]

EXAMPLE To construct the metal cord 3 shown in FIG. 4, seven metal strands 2 obtained by twisting four metal wires (steel wires) 1 having a diameter of 0.175 mm were used, with one center line and six surrounding wires. ,
They were twisted together by the tubular type twisting wire device shown in FIG. The rotation speed of the supply device 5 for supplying the metal strand 2 with the bobbin 4 was 2000 rpm.

Reference numeral 11 denotes an adjusting device of the present invention provided between the collecting portion 7 and the correction device 8. An example of the structure is shown in FIG. 12
Is a rotary support plate that supports a plurality of rollers 13 that are in contact with the metal cord 3 that is twisted and advancing from the axial center vertical direction, and the support plate holds the metal cord by the rollers 13 and The core is rotated in the same direction as the twist direction of the metal cord or in the opposite direction, and the metal cord is rotated to tighten or untwist the cord.

FIGS. 6 and 7 show that the cord 3 is twisted in the twisting direction and in the opposite direction to the twisting speed of 50, 100, and
It is a figure which shows the initial elongation of the metal cord manufactured by giving rotation of 150,200 rpm, and the relationship of formability.

The respective values are values after the final residual torsion is adjusted to 0 (times / 6 m) for each rotational speed, and the initial elongation and the formability are arbitrarily set without affecting the residual torsion. It shows that it is adjustable. Also, for straightness, all are in the range of 5 to 30 (mm / 500mm),
I confirmed that it had no effect.

The value at the rotational speed (rpm) 0 indicates the value of the metal cord according to the conventional method. The relationship between the initial elongation up to 200 rpm and the formability by giving the rotational speed is as follows.
When the rotating direction is the same as the twisting direction, a positive correlation is shown, and when the rotating direction is opposite to the twisting direction, a negative correlation is shown.

In order to further confirm the effect of the number of revolutions on the initial elongation and the formability, as shown in Table 1, other metal wire diameters and metal cords depending on the number of twists have the same values as those obtained by the conventional method. The values of the examples are shown in contrast.

[0027]

[Table 1]

When a plurality of rollers 13 are used to grip and rotate the metal cord 3 as shown in FIG. 3, the diameter of the roller 13 is preferably 10 to 15 times the diameter of the metal cord. However, the surface of the roller that contacts the metal cord is appropriately selected from cermet, metal, rubber, and the like.

Although the roller type adjusting device is easy to design and operate and suitable for industrial production, it is provided with a plurality of guide rings and guide pins made of a material having a high frictional resistance such as hard rubber, and is provided with a metal. Of course, other adjusting devices may be used, such as a cord gripping structure.

Further, as described above, in the embodiment of FIG. 2, the adjusting device is shown installed between the collecting portion 7 and the straightening device 8, but it may be provided after the straightening device 8.

[0031]

EFFECTS OF THE INVENTION According to the present invention, a cord having a required initial elongation and formability without being affected by a shaping ratio or a residual torsion, which is particularly required as a steel tire cord used for reinforcing an automobile tire, is provided. It can be manufactured selectively. Moreover, since the manufacturing is performed by adding an adjusting device to a conventional twisting machine and applying a rotation to the twisted wire, the device is simple, the operation is easy, and it is economical.

[Brief description of drawings]

FIG. 1 is a schematic side view illustrating the operation of the method of the present invention.

FIG. 2 is a schematic side view illustrating the configuration of the device of the present invention.

FIG. 3 is a perspective view illustrating an embodiment of an adjusting device in the device of the present invention.

FIG. 4A is a cross-sectional view of a metal cord, and FIG. 4B is an explanatory diagram showing a configuration of a shaping unit of a twisting machine.

FIG. 5 is a schematic side view illustrating a configuration of a conventional tubular twisting machine.

FIG. 6 is a chart showing the relationship between the initial elongation of the metal cord and the rotation speed.

FIG. 7 is a chart showing the relationship between the formability of a metal cord and the rotation speed.

[Explanation of symbols]

1 metal wire 2 strand 3 metal cord 4 bobbin 5 supply device 6 shaping part 7 collecting part 8 straightening device 9 winding device 10 shaping pin 11 adjusting device 12 rotation support plate 13 roller A metal cord advancing direction B adjusting device Direction of rotation

Claims (5)

[Claims] 1. A plurality of metal strands are twisted together, and then a part of the twisted wire is gripped, and the twisting rotation speed of 1.2 to
A method for manufacturing a metal cord, characterized in that rotation is given at a rotation speed of 15.0%. 2. A metal cord manufactured by the method according to claim 1. 3. A device for twisting a plurality of metal strands, comprising an adjusting device for holding and twisting the twisted wire provided between the twisted portion and the winding portion with a plurality of rollers. A metal cord manufacturing apparatus characterized by the above. 4. In a tubular type twisting machine for twisting a plurality of metal strands, between a gathering unit and a straightening device after twisting, or between the straightening device and a winding device,
An apparatus for manufacturing a metal cord, comprising an adjusting device for rotating the twisted wire by gripping it with a plurality of rollers. 5. The diameter of the plurality of rollers is 10 to 15 times the diameter of the metal cord, and the rotation of the adjusting device is 1.2 to 15.0% of the twisting rotation speed in the same direction as the twisting direction or the opposite direction. The metal cord manufacturing apparatus according to claim 3 or 4, wherein