JPH07133598A - Production of metal cord and apparatus therefor - Google Patents

Abstract

PURPOSE:To produce a metal cord consisting of 2-3 metal filaments suitable for reinforcement having a structure effective in improving durability of rubber articles without causing breakage of the metal filament and lowering of flexural fatigue. CONSTITUTION:A wavy curl having wave pitch (p1) being 0.45-1.70 times longer than cord twist pitch P and having 1.5d-5.0d (d=diameter of metal filament) wave height is applied to the all of metal filaments 1 having n (n=2 or 3) numbers, whose surfaces are subjected to metal plating, by a curl-providing device 5 and further, the filaments are twisted and then untwisted in a pitch (P2) of 0.25P-0.80P by a double false twister 6 and continuously passed through a capstan device 17 provided with groove into twister 7 twice and twisted together in a state keeping helical wavy curl in a normal cord twist pitch P. By this method, lowering of flexural fatigue in the case when wave height for applying curl is enlarged and metal filaments having thick diameter is suppressed and space between filaments through which a rubber is penetrated can also be spread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal cord used for reinforcing rubber articles such as automobile tires, conveyor belts and high pressure hoses, and more particularly, a structure effective for improving the durability of rubber articles. The present invention relates to a method for manufacturing a metal cord having a groove and a manufacturing apparatus used for implementing this method.

[0002]

2. Description of the Related Art Metal cords for reinforcing rubber articles are plated with brass, copper, zinc or other metal on the surface of the material (JISG3502 piano wire) in order to provide adhesion with rubber. Is usually around 0.2 μm, so if there is a part that is not covered with rubber, moisture in the rubber,
When the damage caused on the rubber reaches the metal cord, it will be corroded in a short period of time due to the permeated water from the outside, and the cutting load and fatigue resistance at that location will be reduced. Further, the adhesiveness between the cord and the rubber is deteriorated and peeled off, which may cause quality trouble due to so-called separation of the tire when used for reinforcing an automobile tire. Therefore, in order to improve the rubber coverage of each metal filament composing the metal cord, for example, in Japanese Examined Patent Publication No. 63-63293, each metal filament is separately twisted with a rotating shaving device in which a plurality of shaving pins are alternately arranged. A method and apparatus for manufacturing steel cords have been proposed in which a fixed habit is attached at a pitch smaller than the pitch, and by twisting this twice with a twisting and twisting machine, a gap is created between each metal filament to improve the penetration of rubber. ing.

Further, in Japanese Patent Laid-Open No. 2-307994, one or more filaments among three or more metal filaments constituting a metal cord are passed between a pair of gears to be staggered in a zigzag shape, and the other is There has been proposed a method for manufacturing a steel cord in which a gap that improves the rubber permeability by twisting with a metal filament is created between the filaments.

[0004]

The former two proposals have been developed for the purpose of compensating for the disadvantages of the use of an open cord having a twisted structure and an unstable structure. The former method of squeezing with the squeeze pin is because the squeeze is performed for each individual metal filament,
Equipment costs are high. The tension of the supplier of each metal filament easily influences the size of the habit,
It is difficult to apply uniform slack to each metal filament.
Since the filament is squeezed with the curling pin, it is easy to break the wire. There is a problem that the twisting becomes unstable because the misaligned phase of each filament is likely to shift at the gathering port of the double twisting and twisting machine.

In the latter method in which the gears are squeezed, since the squeezing is a two-dimensional corrugation along the tooth surface, when the corrugations are applied to all the filaments and twisted, the twists are not uniform. However, there is a concern that the bending fatigue property may be deteriorated, and it is difficult to apply it to the reinforcement of a portion requiring bending fatigue performance such as a breaker portion and a carcass portion of an automobile tire.

The present invention has the above-mentioned manufacturing or quality,
An object of the present invention is to provide a manufacturing method and a manufacturing apparatus of a metal cord which can eliminate the cost problem and at the same time prevent the deterioration of bending fatigue property and improve the rubber coverage of each metal filament.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has n (n = 2 or n) diameters d of 0.25 mm to 0.35 mm with metal plating on the surface. 3) In the method for producing a metal cord formed by twisting metal filaments, as a pretreatment, the wave pitch p ₁ is 0.45 to 1.70 times the cord twist pitch P for all the metal filaments before twisting, Wave height is 1.5d
~ 5.0d wavy habit, then, this quirky metal filament is passed through a double false twisting device, twisted and untwisted at a pitch p ₂ = 0.25P to 0.80P, and held here. After that, the metallic filaments whose habit has changed into a spiral wave shape are continuously passed through a double twisting and twisting machine to be twisted together at a regular cord twist pitch P so as to maintain the spiral wave habit.

As for the manufacturing apparatus for carrying out this method, a squeezing apparatus and a double false twisting apparatus in which a plurality of pins are alternately arranged are provided, and the squeezing apparatus is provided in the preceding stage of the double false twisting apparatus. It is provided between a metal filament supply reel and an out-in type double twisting and twisting machine.

The spiral direction of the spiral wave applied to the metal filament by the double false twisting device is preferably the same as the regular twisting direction of the cord. This can be realized by making the rotation directions of the double false twisting device and the double twisting wire machine the same.

Further, it is desirable that the average twist pitch of the temporary metal cords formed immediately after the double false twisting device is in the range of 2.1 to 4.0 times the finally obtained cord twist pitch P. Therefore, the distance between the untwisting side second turn roller of the double false twisting device and the grooved capstan device is set to Li,
Let Lo be the distance between the grooved capstan device and the first turn roller of the double-twisting wire machine, and let P be the finally obtained cord twist pitch, and Li> Lo and Li + Lo ≧
It is recommended to meet the 30P relationship.

[0011]

[Function] When manufacturing various metal cords with a double twisting and twisting machine, the shape of the wave obtained, especially the height of the wave, can be obtained by pretwisting and then untwisting to give a small spiral wave-like habit to the metal filament as a pretreatment. There is a limit to the size, which is not preferable. Therefore, in the manufacturing method and the manufacturing method of the present invention, a curling device is arranged immediately before the false twisting device so that the wave height can be controlled on the large side.

To further describe this point, the inventors of the present invention have disclosed in Japanese Patent Laid-Open No. 5-171579 that maintenance of the twist of a metal cord after twisting with a double twisting wire twisting machine and adjustment of residual twist. It has been proposed to use a double false twisting device, which is a device for further improving false twisting for the purpose. According to this method, a spiral wave-like habit with a pitch of 0.25 to 0.8 times the twist pitch (preferably a constant pitch), which is much finer than the habit of a twist pitch that is conventionally performed, is very fine. Since the wires are twisted after being twisted, the fine curl shape given to each metal filament is determined by the diameter of the filament, the number of false twists, and the false twist pitch. There is no deviation. Therefore, a cord having a uniform gap between filaments and a stable twist can be obtained, and there is no filament breakage, and a cord having a high rubber coverage can be easily obtained. Also,
Since the eccentric shape imparted to each metal filament is a three-dimensional spiral wave shape, there is no decrease in bending fatigue performance due to stress concentration.

Further, the false twisting device used for the squeezing is a conventional false twisting device (for squeezing each filament along the twist pitch and the radial direction of the cord and for removing residual stress inherent in each filament). If a double false twisting device that can obtain twice the false twist is used, an increase in equipment cost can be suppressed. That is, if the false twisting device used is the same as before,
For example, in order to make a fine curl to a filament around 0.5 times the cord twist pitch, the number of revolutions of the false twisting device must be 4 times the number of revolutions of the double twisting and twisting wire machine. With a twisting device, the same purpose can be achieved with twice the number of rotations, and many advantages can be obtained, such as easy facilitation of fine curling with inexpensive equipment.

It should be noted that the pitch of the spiral wave-like habit added in advance is limited to 0.25P to 0.80P (P = cord twist pitch) because the tendency that the habit disappears when the main twist is made if this pitch is too large. On the contrary, if it is too small, the twisting amount of the metal filament becomes large and the cord strength is reduced, and the area between the obtained filament gaps is too small to sufficiently increase the rubber coverage. The twisting pitch is adjusted by controlling the rotation speed of the double false twisting device.

However, in the case of the metal cord to which the present invention is directed, the number of the metal filaments is 2 to 3 and which meets the demand for weight reduction, it is necessary to make the diameter of the metal filament large in order to secure the cord strength. Occurs, that much,
There is concern about deterioration in bending fatigue resistance. In order to compensate for this, it is necessary to control the height of the wave to a large side, but since the technique of the prior application alone has a limit in this point, new invention was added to arrive at the present invention.

According to the present invention, the false twisting pitch p ₂ (0.25P) by the double false twisting device is first applied to all the metal filaments before they are twisted together by using the curling device in which a plurality of pins are arranged in a staggered pattern. .About.0.80P) and a pitch p ₁ (0.45P-1.70P) which is about twice as high as the wave height 1.
A large habit of 5d to 5.0d is added, and then, as shown in the prior application, the product is passed through a double false twisting device and 0.25P to 0.
False twisting is performed at a pitch p ₂ of 80P.

In FIG. 1, the reason why the peculiar pitch p ₁ by the peculiar setting device is about twice the false twist pitch p ₂ is as follows.
The double false twisting device 6 is added from the exit of the curling device 5 (excess)
The false twist pitch up to the first turn roller 11 on the twist side is still in the middle of false twist, and is about twice the final false twist pitch. Therefore, the false twist pitch (p≈2p ₂ ) is set to a value corresponding to that, and the upper and lower limits are set. I chose a range where there is no twist. Also, the wave height is maximum when only the double false twisting device is used, 1.0d when n = 2 and 1.15d when n = 3.
However, it is necessary to consider the bending fatigue resistance especially in the structure of a single twist of 2 or 3 strands. Therefore, consider the frictional resistance of various guide rollers after the double false twisting device, and twist them together. Later, it was set to the above range as a value capable of maintaining a corrugated shape of an appropriate size.

Next, the reason why the spiral wave winding direction to be false-twisted by the double false-twisting device and applied to the metal filament is preferably the same as the regular twisting direction of the cord is as follows. First, it is extremely important that the direction of the spiral wave habit is the same as the twisting direction. In the opposite direction, the spiral wave-like habit is returned at the time of twisting and the peculiar peculiar pitch becomes large.Therefore, it is necessary to add a finer wavy peculiarity in advance to obtain the desired peculiar peculiar pitch after the final twist. As a result, not only the manufacturing becomes difficult, but also the wavy curl return is likely to be uneven, and the twisting is difficult to stabilize particularly in the double-twisting machine.

In the same direction, a spiral wave-like habit is added at the time of twisting and the peculiar pitch is reduced. Therefore, a spiral wave peculiarity larger than the peculiar peculiar pitch in the twisted state may be added to facilitate the production. The twist is also stable. To do so, the double false twisting device and the double twisting and twisting machine may be rotated in the same direction. This is because the habit attached on the addition (over) twisting side of the double false twisting device is used.

Further, regarding the average twist pitch of the metal cord located between the double false twisting device and the double twisting wire twisting machine.2.
The reason why the range of 1P to 4.0P is desirable is as follows.

Assuming that there is no double-twisting wire machine after the double false-twisting device, the metal cord false-twisted on the additional (over) twisting side is unrolled in FIG. Since the twist is untwisted on the twisted side as a matter of course, the shape of the cord is not retained and the metal filament is in a stiffened state. However, in reality, the double false twisting device and the double twisting twisting machine are arranged in series via the grooved capstan device, and the double twisting twisting machine is installed on the untwisting side immediately after the double false twisting device. Backlash propagation of the twist is moderated by the grooved capstans, which creates a temporary metal cord.

If the average twist pitch of this temporary metal cord is too small, the backflow propagation of the twist reaches the holding roller portion of the above twist sufficiently, so that the friction between the two turn rollers 15 and 16 on the untwisting side is correspondingly increased. The resistance increases, and the corrugation tends to disappear. On the other hand, if the average twist pitch of the temporary cord is too large, twist formation is insufficient, and pitch unevenness is likely to occur. As a result of studying in consideration of both of these phenomena, the range of 2.1P to 4.0P described above was found as an appropriate value.

The twist pitch of the temporary metal cord depends on the backflow propagation speed of the twist from the double twist wire machine. There are two main factors that influence the backflow velocity: the regular twist pitch of the cord and the length of the temporary metal cord. Therefore, when the relationship between the length of the temporary metal cord and the regular twist pitch of the cord was also examined, the length of the temporary metal cord,
That is, the distance between the second turn roller 16 of the untwisting side of the double false twisting device and the first turn roller 18 of the double twisting and twisting machine is 30 times or more of the finally obtained cord twisting pitch P. The design in which the grooved capstan installed between them is arranged closer to the double twisting and twisting machine side than the intermediate point between the two is preferable because it is easy to maintain the average twisting pitch of the temporary metal cord in the above-mentioned appropriate range.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the metal cord manufacturing apparatus of the present invention. Reference numeral 8 in the drawing is a supply reel for feeding out the non-settling metal filament 1, 5 is a stapling device having staggered staggering pins 9, 10 is a collective die,
6 is a double false twisting device, 7 is a double twisting and twisting wire machine, 17 is Li
> Lo and Li + Lo ≧ 30P (P is the twist pitch of the cord finally obtained) and the grooved capstan arranged between the double false twisting device 6 and the double twisting and twisting machine 7 is satisfied. is there.

The double false twisting device 6 includes the first (first) on the additional (over) twisting side.
It has a turn roller 11 and a second turn roller 12, a twist holding roller 14 installed in a cradle 13, a first turn roller 15 and a second turn roller 16 on the untwisting side. The double twisting and twisting machine 7 includes a first twisting first turn roller 18, a second twisting turn roller 19, and a flyer 2.
0, a single false twisting device 21, a take-up capstan 22, and a take-up reel 23.

A detailed description will be given below by taking as an example a case where the metal cord 3 having a 1 × 2 single twist structure shown in FIG. 2 is manufactured by using this exemplified manufacturing apparatus.

First, the metal filament 1 that has not been laid out and is fed from the reel 8 is passed through the lining device 5 to form a substantially two-dimensional wavy habit. (The waveform immediately after this is a spiral shape due to the backflow of the twist from the double false twisting device.) This habit is that the pitch of the wave is false twisted by the double false twisting device 6 in the next stage. About 2 of the pitch
And the height of the wave was about 3 times the filament diameter d. Next, the metal filaments 2 that have been stiffened are assembled into a die 10.
Are collected and sent to the double false twisting device 6, where they are twisted and then untwisted to obtain a regular spiral wave-like habit. At this time, as shown in the figure, when the double false twisting device 6 is rotated in the same direction as the double twisting and twisting machine 7, the spiral direction of the spiral wave attached to the metal filament 2 is in the normal direction of the cord. Match the twist direction. The effect (facilitation of manufacturing and improvement of twist stability by reducing the number of rotations) has been described in detail above.

The metal filament passing through the double false twisting device 6 is fed from the double twisting and twisting machine 7 to the grooved capstan device 1.
The twisted wires 7 are appropriately controlled by the twisted wires 7 and are twisted with each other by the back-propagating twisted wires, so that the temporary metal cord 4 is obtained. This temporary metal cord 4 is introduced into the double twisting and twisting machine 7,
Twist in a tight twist with a regular twist pitch,
Further, when the twist is fixed, a desired metal cord is finished.

The appearance of the metal cord 3 obtained by this method is shown in FIG. 2 (a), and its cross section is shown in FIGS. 2 (b) and 2 (c).

The filament 2 is inscribed in the small circle A and is in a state of drawing a large spiral in the longitudinal direction of the filament. Therefore, a gap due to the diameter difference between the small circle A and the metal filament diameter d (this is the residual amount of the stiffening height) is generated between the opposing filaments, the rubber penetration is improved, and the rubber coverage is increased. . Further, the metal filament 2 has a small spiral wave and has a margin of elongation and a spring effect for relaxing an external force, which leads to maintenance or improvement of bending fatigue property.

The shape of the curling can be freely set depending on the size of the curling applied by the curling device 5 and the double false twisting device 6 and the manufacturing conditions at the location of the double twisting and twisting machine 7, but the pitch of the wave. p ₂ is 0.25 because of the reason described above.
~ 0.80P (P; cord twist pitch),
The height of the wave is determined so that it remains at least 0.05 mm after the cords are twisted together.

[0032]

As described above, according to the manufacturing method of the present invention, in consideration of bending fatigue resistance, in order to obtain the inter-filament gap required for rubber intrusion, all the metal filaments are preliminarily squeezed. A wave with a particularly large height (1.5 to 5.0 times the filament diameter) is attached, and then a predetermined pitch (0.25 to 0.80 times the cord twisting pitch) between the metal filaments by the double false twisting device. ) After untwisting, the average twisting pitch of the temporary metal cord located between the double twisting and twisting machine in order to retain the habit imparted to the filament and to maintain the evenness of the twisting. Is adjusted to an appropriate value (2.1 to 4.0 times the twist pitch obtained at the end), so that there is no manufacturing problem such as filament breakage, and the metal cord has a uniform gap between metal filaments and a stable twist. Obtained, the corrosion resistance is improved by increasing the rubber coverage. At the same time, the uniform spiral wave-like habit of the metal filament enhances the ability to absorb an external force and also improves the bending fatigue resistance.

Further, when the manufacturing apparatus of the present invention is used, the corrugated shape can be easily controlled, and since the pre-curling and the main twist can be continuously performed, it is advantageous in terms of productivity, manufacturing and equipment cost. Become.

Therefore, it is particularly effective when used for the production of reinforcing metal cords for automobile tires, high pressure hoses, conveyor belts, etc., where durability and safety are important.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a manufacturing apparatus and a manufacturing method of the present invention.

FIG. 2A is an external view of a pseudo compact cord obtained by the method of the present invention. FIG. 2B is a cross-sectional view taken along line bb of FIG. 2A. Cross section of

[Explanation of symbols]

 1 Metal filament before curling 2 Curled metal filament 3 Metal cord 4 Temporary metal cord 5 (Primary) Curling device 6 Double false twisting device 7 Double twisting and twisting machine 8 Supply reel 9 Curling pin 10 Assembly Dies 11 Addition (Over) Twisting Side First Turn Roller 12 Twisting Side Second Turn Roller 13 Cradle 14 Twisting Holding Roller 15 Untwisting Side First Turn Roller 16 Untwisting Side Second Turn Roller 17 Grooved Capstan 18-twist first turn roller 19-twist second turn roller 20 Flyer 21 (single) false twisting device 22 Take-up capstan 23 Take-up reel

Claims (6)

[Claims] 1. The diameter d of the metal-plated surface is 0.
N in the range of 25 mm to 0.35 mm (n = 2 or 3)
As a pretreatment for twisting, the wave pitch p ₁ is 0.45 of the cord twist pitch P for all the metal filaments of
1.70 times, wave height of 1.5d ~ 5.0d (d = diameter of metal filament) wavy habit, then, this quirky metal filament is passed through a double false twisting device to pitch. After plying at p ₂ = 0.25P to 0.80P, untwisting is performed, and then the metal filament, which has a habit of changing into a spiral wave shape, is continuously passed through a double twisting and twisting machine to form a regular cord twisting pitch. A method for producing a metal cord, which comprises twisting in a state in which a spiral wave-like habit is held by P. 2. The method for producing a metal cord according to claim 1, wherein the spiral winding direction of the spiral wave applied to the metal filament by the double false twisting device is the same as the regular twisting direction of the cord. 3. The average pitch of twisting of the temporary metal cord formed immediately after the double false twisting device is controlled to 2.1 to 4.0 times the finally obtained cord twisting pitch P.
Alternatively, the method for producing the metal cord according to 2 above. 4. A reel for supplying n (n = 2 or 3) metal filaments, a plurality of pins arranged in a staggered arrangement, and squeezing the metal filaments with the pins to make all of the metal filaments wavy. A quasi-twisting device that changes the habit of each filament into a spiral wave by twisting the metal filament that has passed through the quasi-twisting device, from a double-twisting machine to a double-twisting device. It is equipped with a grooved capstan device that controls the reverse flow of twisting properly, and a double twisting and twisting machine that twists the metal filament after false twisting at a regular twist pitch to hold a small spiral wave habit. Metal cord manufacturing equipment. 5. The apparatus for producing a metal cord according to claim 4, wherein the double false twisting apparatus and the double twisting and twisting machine have the same rotating direction. 6. The distance between the untwisting side second turn roller of the double false twisting device and the grooved capstan device is Li, and the distance between the grooved capstan device and the first turn roller of the double twisting and twisting wire machine. Is defined as Lo and P is the finally obtained cord twist pitch, and the relationship of Li> Lo and Li + Lo ≧ 30P is satisfied.