JPH05171579A - Apparatus and method for producing metallic cord for reinforcement of rubber article - Google Patents

Abstract

PURPOSE:To produce a reinforcing metal cord having a structure effective for improving the durability of a rubber article without causing the breakage of metallic filament, the lowering of flexural fatigue resistance and the increase of elongation in the low load range. CONSTITUTION:A plurality of non-twisted metal filaments are passed through a double twisting apparatus 4 to apply a false-twisting at a pitch corresponding to 0.25-0.80 times the twisting pitch of cord. The false-twisted filaments are untwisted to obtain filaments having spiral form. The formed metal filaments 2 and metal filaments 1 free from the forming treatment are guided to a collection dies 5 and passed through a double-twisting machine 6 to twist at a regular cord-twisting pitch. The small spiral form applied to the filament 2 is uniformly stabilized in the longitudinal and radial directions of the cord. The cord is resistant to the phase shift of the formed filament, contains uniform gap between filaments and has excellent impregnation property of rubber, stable twist and low elongation under a low load. There is no lowering of the flexural fatigue resistance caused by the stress concentration on the filament because the formed filament has spiral form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing 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. And a manufacturing method using the same.

[0002]

2. Description of the Related Art Metal cords for reinforcing rubber articles have a metal (JISG3502 piano wire) surface plated with brass, copper, zinc or the like 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, water in the rubber,
When the rubber damage reaches the metal cord, it penetrates from the outside and is corroded in a short period of time, and the cutting load and fatigue resistance of the area are reduced. Further, the adhesiveness between the cord and the rubber is deteriorated and the rubber is peeled off, and when it is used for reinforcing an automobile tire, there is a possibility of causing quality trouble due to so-called separation of the 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 constant habit is attached at a pitch smaller than the pitch and twisted twice with a twisting and twisting machine to create a gap 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, which is then attached to another. There has been proposed a method for manufacturing a steel cord in which a gap that improves the rubber penetration is created between the filaments by twisting the filament with a metal filament.

[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 a squeeze pin is because squeeze is done for each individual metal filament,
Equipment costs are high. The tension of each metal filament is easily influenced by the tension of the supplier,
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 misalignment phase of each filament is apt to shift at the gathering port of the double twisting and twisting machine, and the twisting becomes unstable.

Further, in the latter method in which the gear is squeezed, since the squeezing is a two-dimensional corrugation along the tooth surface, the stress concentration in the tooth profile is remarkable and the bending fatigue property is greatly reduced. Therefore, there is a problem that it is difficult to apply it to 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 apparatus and a manufacturing method of a metal cord for reinforcing a rubber article, 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 problems, the present invention provides n (n) metal platings on the surface.
≧ 2) In the method for producing a metal cord for reinforcing a rubber article by twisting metal filaments, a plurality of metal filaments before being twisted are passed through a double false twisting device to obtain a cord twist pitch of 0.25 to 0. This s metal filament (n ≧ s ≧ 2) and non-crimped (n−s) metal filaments, which have been false twisted and then untwisted at a pitch of 80 times, and then have a spiral wavy habit. Is passed through a double twisting and twisting machine at a regular cord twisting pitch, and the twisted metal filaments are twisted after twisting, separately from the twisting twist, 0.20 to 0.45 times the cord twisting pitch, filament radial direction Height is 0.02-0.15mm
It is designed to be twisted in such a manner as to hold the spiral wave-like habit.

In this method, when s = n, the number of metal filaments which are not stiffened is 0, and only the stiffened metal filaments are twisted together.

The manufacturing apparatus of the present invention used for carrying out this method is naturally equipped with a double false twisting apparatus in front of the double twisting and twisting machine for twisting n (n ≧ 2) metal cords. It will be what was made.

[0010]

According to the apparatus of the present invention and the method using the same, when manufacturing various metal cords with a double twisting and twisting machine, the target filaments are once gathered, false twisted, untwisted, and then separated and separated. In order to introduce it to the double-twisting wire machine, in more detail, the double-twisting wire machine was further devised for temporary twisting for the purpose of maintaining the evenness of the twist of the metal cord after twisting and adjusting the residual twist. Using a false false twisting device, give a spiral wave-like habit with a pitch of 0.25 to 0.8 times the twist pitch, which is much finer than the habit of the conventional twist pitch. For matching, the finely curled shape imparted to each metal filament is determined by the diameter of the filament, the number of false twists, and the false twist pitch, and is uniform and stable in both the cord longitudinal direction and the diametrical direction, and no phase shift occurs. 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 shape, there is no decrease in bending fatigue performance due to stress concentration.

Further, the false twisting device used for the curling is a conventional false twisting device (for the purpose of eliminating the curling of each filament along the twist pitch and the radial direction of the cord and removing residual stress inherent in each filament). If the double false twisting device that can obtain double the false twist is used, the increase in the equipment cost can be suppressed. That is, if the false twisting device used is the same as before,
For example, in order to make the fine curl to the filament about 0.5 times the cord twist pitch, the number of revolutions of the false twisting device must be set to 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 fine curling can be easily performed with inexpensive equipment.

The metal cord produced by the method of the present invention preferably has two or more of the n metal filaments to be stiffened. Even if only one stiffened metal filament penetrates the rubber into the cavity at the center of the cord, in order to improve the rubber permeability and increase the rubber coverage, the number of stiffened filaments should be two or more. It is advantageous to allow the rubber to enter from different directions.

In addition, if the peculiar pitch is equal to or greater than the twist pitch of the cord, the peculiarity disappears due to resistance with various guides during double twisting, and the filament interval necessary for rubber penetration cannot be maintained. If the twist pitch of the cord is less than 0.2 times, the twist amount of the metal filament becomes large, and when the cord is formed into a cord, not only the strength of the cord is remarkably decreased, but also the clearance area between the filaments becomes small and the rubber becomes smaller. It is not preferable because it hardly penetrates and the rubber coverage is lowered. As a result of examining the appropriate value,
The gap between filaments required for rubber penetration is 0 at the maximum.
It is more than 02mm, and the range of the fine curl pitch that can easily hold it is 0.25 of the cord twist pitch.
It was found to be 0.8 times. It is even better to keep the habit pitch constant within this range. The false twist pitch is adjusted by controlling the rotation speed of the double false twist device.

[0014]

[Examples] With respect to the manufacturing method of the present invention, a metal cord in which three metal filaments with small wavy habits and two metal filaments with no quirks are twisted with respect to a 1 × 5 single twist structure are illustrated. The details will be described by taking as an example the case of manufacturing using the manufacturing apparatus of the present invention shown in FIG.

As shown in the figure, three metal filaments are false-twisted by a double false-twisting device 4 and then untwisted to obtain a filament 2 having a small wavy habit in a three-dimensional spiral form. At this time, the double false twisting device 4 is rotated in the same direction as the double twisting and twisting machine 6 in order to suppress an increase in the number of rotations, and the winding direction of the wave of the filament 2 is matched with the twisting direction of the cord. is important. These metal filaments 2 with a habit and two metal filaments 1 without a habit are guided to a collecting die 5, and then introduced into a double twisting and twisting machine 6 and twisted in a tight twisted state.

Before being guided to the collecting die 5, the metal filaments 2 which have been stiffened at 4 are once completely separated by the separating / dividing device 12 and then twisted together. This is a particularly effective process when the number of metal filaments to be struck is large.

When twisting the stiffened metal filament 2 and the non-stiffened metal filament 1, the metal filaments 1 and 2 are passed through a positioning device 14 before being guided to the assembly die 5, and this device is used. It is desirable that the fibers are appropriately dispersed and positioned at 14 and then twisted together. This dispersive positioning improves the dispersibility of the gap formed between the stiffened metal filament 2 and the adjacent filament, and facilitates rubber penetration into the inside of the cord at each portion in the cord longitudinal direction. When the number of metal filaments to be twisted together is large (4 or more), the effect of the gap distribution by the dispersion positioning is remarkable.

A cross section of the metal cord 3 obtained by this method is shown in FIG. 2 (c). Curled metal filament 2
Is inscribed in the small circle a while drawing a small spiral in the longitudinal direction of the filament, and in this state is inscribed in the great circle A and drawn in a large spiral in the longitudinal direction of the cord. Therefore, a gap is formed between the adjacent filaments due to the diameter difference between the small circle a and the metal filament 2 (this is the residual amount of the stiffened height), and the rubber permeability is improved. Further, since the habit imparted to the metal filament 2 has a small spiral wave shape, the bending fatigue property does not deteriorate. The shape of the peculiar shape can be freely set depending on the size of the peculiarity of the double false twisting device 4 and the manufacturing conditions at the location of the double twisting and twisting wire machine 6, but for the reason described above, the peculiar pitch is 0. 25 to 0.8 P (P = cord twist pitch). Also, the curl height is set so that 0.02 mm or more remains after twisting the cords.

A more detailed embodiment will be described below.

Example 1 Three brass-plated metal filaments having a diameter of 0.28 mm, one of which was not squeezed, and the other two were passed through a double false twisting device to give a false twisting pitch of 0. After making a straitjacket at .45P and once separating and dividing, both are guided to the collecting port of the double twisting and twisting machine and twisted at a twisting pitch P = 15mm,
A 1 × 3 × 0.28 semi-compact cord (SC) having a cross-sectional shape as shown in (a) was obtained.

Example 2 Four brass-plated metal filaments having a diameter of 0.25 mm, two of which were not squeezed, and the other two were passed through a double false twisting device to give a false twisting pitch of 0. After the straightening with 53P and the separation / segmentation, the two are alternately rearranged, guided to the collecting port and twisted with P = 12 mm, and the cross-sectional shape as shown in FIG. 2 (b) is 1 × 4 × 0. 25 S, C, C were obtained.

Example 3 Five brass-plated metal filaments having a diameter of 0.25 mm were not struck, and the remaining three were squeezed at a false twisting pitch of 0.58 P by a double false twisting device. Separation / segmentation, and the two are alternately rearranged and led to the collecting port P = 10
1 of the cross-sectional shape as shown in FIG.
S × C × C of × 5 × 0.25 was obtained.

-Example 4-Three brass-plated metal filaments having a diameter of 0.28 mm are passed through a three-fold double false-twisting device to be bent at a false-twisting pitch of 0.50 P, and once separated and separated. Then, these were led to a collecting port and twisted at P = 15 mm to obtain a 1 × 3 × 0.28 semi-compact cord (S · C · C) having a cross-sectional shape as shown in FIG. 3 (a).

Example 5-Five of brass-plated metal filaments having a diameter of 0.25 mm are passed through a co-double false-twisting device with a false-twisting pitch of 0.61.
After habituation at P and separation line, lead to the collecting port and P = 1
By twisting at 0 mm, 1 × 5 × 0.25 S · C · C having a cross-sectional shape as shown in FIG. 3B was obtained.

-Comparative Example-For comparison with the codes of the above-mentioned examples, conventional closed codes (C / C) and open codes (O / C) having the construction shown in Table 1 were prepared. In addition, a corrugated cord (WC) which was twisted in a zigzag pattern through a metal filament between a pair of intermeshing tooth surfaces each having a tooth profile having a pitch and height of 3 mm was also prepared as a comparative example. In all the comparative examples, the twist pitch is P = 10 mm.

For each of the above metal cords, the rubber coverage inside the cord, which is a substitute characteristic of corrosion resistance, the elongation at low load region and the bending fatigue property were investigated. The results are also shown in Table 1.

As can be seen from the table, in all of Examples 1 to 5, the rubber coverage determined by the quality of the rubber penetration is large and the low load range elongation is small, as compared with the comparative example. Further, the bending fatigue resistance has been obtained at the same level as that of the closed cord (C / C).

[0028]

[Table 1]

In FIG. 1, one double false twisting device 4 is provided and one double twisting and twisting machine is provided. However, one double false twisting device is arranged behind the double false twisting device. Multiple rotating double-twisting and twisting machines are arranged in parallel, and the false-twisting and untwisting metallized filaments are distributed from the double false-twisting device to each of the double-twisting false-twisting devices. It is also possible.

Further, the manufacturing apparatus of FIG. 1 is provided with a separating / dividing device 12 and a positioning device 14, but these are preferable devices and are not an essential element of the present invention.

Further, the apparatus and method of the present invention are not limited to the single twist structure exemplified here, but may be 3 + 6, 3 + 9, 3+.
Multi-layer twist structure such as 9 + 15 or 1x12, 1x19, 1x
It can also be applied to the production of cords having a bunched twist structure such as 27.

[0032]

As described above, by using the manufacturing apparatus of the present invention, it is possible to continuously carry out the preliminary twisting and false twisting by false twisting and untwisting, which is advantageous in terms of productivity and manufacturing cost. become. In addition, according to the manufacturing method of the present invention using this apparatus, the double false-twisting device is used to impart a habit to obtain the inter-filament gap required for rubber penetration, at a predetermined pitch (cord twisting pitch of 0 between metal filaments). .25 to 0.80 times) and then twisting is performed after false twisting, so that a metal cord having a uniform gap between metal filaments and a stable twist can be obtained without causing problems in production such as filament disconnection. The coverage is increased and the corrosion resistance is improved.

Further, there is no decrease in bending fatigue, and
Since the elongation in the low load range is small, quality problems during use can be solved. Therefore, it is particularly effective when used for manufacturing metal cords for reinforcing rubber articles such as 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. 2 is a sectional view of a semi-compact cord obtained by the method of the present invention.

FIG. 3 is a sectional view of a pseudo compact cord obtained by the method of the present invention.

[Explanation of symbols]

 1 Metal filament which is not squeezed 2 Metal filament which is squeezed 3 Metal cord 4 Double false twisting device 5 Assembly die 6 Double twisting and twisting machine 7 Supply reel 8 Twisting side turn roller 9 Untwisting side turn roller 10 Credor 11 Twisting holding roller 12 Separation / dividing device 13, 16 Roller eye plate 14 Positioning device 15 Guide roller 17 Flyer 18 Take-up reel 19 Assembly die

Claims (4)

[Claims] 1. A double false twisting device is provided in front of a double twisting and twisting machine, and of s (n ≧ s ≧ 2) of n (n ≧ 2) metal filaments constituting a cord. Before the metal filament is twisted by the double twisting and twisting machine, it is passed through this double false twisting device, where it is twisted and then untwisted so that a small spiral wave-like habit is added to the s metal filaments. An apparatus for manufacturing a certain metal cord for reinforcing rubber articles. 2. Separation between the double twisting wire machine and the double false twisting device, the metal filament which is false twisted and untwisted by the double false twisting device is once completely separated, and is sent to the double twisting wire machine. An apparatus for manufacturing a metal cord for reinforcing a rubber article according to claim 1, further comprising a branching device. 3. Between the separating / separating device and the double twisting / twisting machine, each of the metallic filaments after separating / separating and (nS) metal filaments which have not been squeezed are more appropriately provided. The apparatus for manufacturing a metal cord for reinforcing a rubber article according to claim 2, further comprising a positioning device for dispersing and positioning. 4. n pieces (n ≧) whose surface is plated with metal.
In the method for producing a metal cord for reinforcing a rubber article, which comprises twisting metal filaments according to 2), a plurality of metal filaments before twisting are passed through a double false twisting device, and a cord twist pitch of 0.25 to 0.80. This s metal filament (n ≧ s ≧ 2) and the non-crimped (n−s) metal filaments which are false-twisted at a double pitch and then untwisted and then spiral-wavy A method for producing a metal cord for reinforcing a rubber article, which comprises passing the resin through a twice-twisting machine and twisting the cords at a regular cord twisting pitch.