JP3708379B2 - High rigidity steel cord for rubber reinforcement - Google Patents

Description

【００１９】
第１表において、コード直径はコードを平面に配し、平面よりコード高さを測定したものである。従来例２のコード直径も同様に測定したものである。
「剛性」は供試スチールコードを１００ｍｍの間隔で固定し、それら両側の固定部の接線が１５°になるようにスチールコードを曲げたときの曲げモーメントを測定したものである。
「ゴム浸透性」は引き剥ぎ法によって測定した結果である。
【００２０】
第１表から明らかなように、実施例１，２，３は従来例１に比べて剛性が１４〜１５％向上しており、従来例２にほぼ匹敵する高剛性が実現されている。一方、コード径については、実施例のものは従来例２よりも小さく、従来例１とほぼ同等である。
【００２１】
【発明の効果】
以上説明した本発明によるときには、Ｎ（Ｎ＝２〜５）＋Ｍ（Ｍ＝１〜３）構造でしかもワイヤ本数がＮ≧Ｍのスチールコードにおいて、第１のワイヤ束は相互に撚り合わされずに集合され全体として長手方向に螺旋状を呈しており、この束に第２のワイヤ束が巻き付けられ、コード長手方向と直角の断面において常にコード外接円の中心が略直線上に存するので、第１束の突出しが抑制されるとともに、剛性が高くしかもそれでいてコード径が同本数の１×ｎあるいはｎ＋ｍのコードよりも小さいものとなり、それによりベルト層などのゴムシートに埋設したときのゴム複合体厚さを薄くすることができ、乗り心地や操縦安定性がよく軽量なラジアルタイヤ類を得ることができ、ことに、前記第１ワイヤ束は、上下方向と左右方向に同一高さで波付けされ、上下と左右の波付けピッチは半ピッチ位相がずれていることによって構成され、各ワイヤの波ピッチは１２．０＜Ｐ＜２０．００ｍｍ、波付け高さは０．７０ｄ＜Ｈ＜１．２０ｄ（ｄはワイヤの直径ｍｍ）であるので、剛性の向上とコード外径のコンパクト化を確実に実現できるというすぐれた効果が得られる。
【図面の簡単な説明】
【図１】（ａ）は本発明によるスチールコードの一例を拡大して示す側面図、（ｂ）は（ａ）におけるａ−ａ，ｂ−ｂ，ｃ−ｃ，ｄ−ｄ，ｅ−ｅの各位置の断面図である。
【図２】（ａ）は本発明における第１束のワイヤの側面図、（ｂ）は同じくその平面図、（ｃ）は同じくその正面図である。
【図３】（ａ）ないし（ｄ）は本発明によるスチールコードの他の例を異なる位置で切断した断面図である。
【図４】本発明のスチールコードの製造装置と製造方法を模式的に示す説明図である。
【図５】図４における波加工装置部分の詳細図である。
【符号の説明】
１ 第１束
２ 第２束
１０ａ，１０ｂ，１０ｃ 第１束のワイヤ
２０ａ，２０ｂ，２０ｃ 第２束のワイヤ
Ｃ コードの中心
ＣＬ コード中心線
Ｄ コード外接円
１０１ 波[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steel cord for reinforcing rubber, particularly a steel cord having high rigidity.
[0002]
[Prior art]
Steel cords are used as reinforcing materials in rubber products such as tires for vehicles such as trucks. Conventionally, as this type of steel cord, a 1 × n structure such as 1 × 5 in which a plurality of wires with plating are twisted at the same time is widely used. However, in recent years, from the aspect of ride comfort and handling stability, etc. There is a need for a more rigid steel cord.
[0003]
In addition, an N + M structure steel cord has been proposed as a steel cord. This steel cord has a relatively high rigidity as compared with a steel cord having a 1 × N structure in which flexibility is obtained by twisting.
However, in this steel cord, bundles of multiple steel wires that make up the core are not twisted together, so there is a problem that so-called tension occurs and separation phenomenon occurs, and the center of the core wire bundle is corded. Since the second wire bundle is wound around the outer periphery in alignment with the center, the irregularities on the outer periphery are larger than those of the 1 × n cord, and as a result, when embedded in the rubber sheet, the rubber composite, for example, the belt layer There was a problem that the thickness was increased, and the weight reduction and cost reduction were impaired.
[0004]
[Problems to be solved by the invention]
The present invention was devised to solve the above-described problems, and the object of the present invention is to provide a cord having high rigidity, less first wire bundle tension and an outer diameter of 1 × n structure. The object is to provide a high-strength steel cord for reinforcing rubber capable of reducing the thickness of a rubber sheet that is as compact as possible.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a steel cord having an N (N = 2 to 5) + M (M = 1 to 3) structure and a number of wires N ≧ M, the first wire bundles are twisted together. The second wire bundle is wound around this bundle and the center of the cord circumscribing circle is always on a substantially straight line in the cross section perpendicular to the cord longitudinal direction. The first wire bundle is corrugated at the same height in the vertical direction and the horizontal direction, and the vertical and horizontal corrugation pitches are configured by a half-pitch phase shift, and the wave pitch of each wire is It is characterized in that 12.0 <P <20.00 mm and the corrugation height is 0.70d <H <1.20d (d is the diameter of the wire mm).
[0006]
[Action]
In the conventional N + M structure, the center of the wire bundle composed of a plurality of wires that are not twisted together is arranged on the center line of the cord, and the wire bundle composed of the plurality of wires is wound around the outer periphery of the wire bundle. there were.
The present invention changes this idea, the first wire bundle is spirally formed in the longitudinal direction of the cord, and the center of the first wire bundle is intentionally shifted from the center of the cord, and in this state, the second wire bundle is I am trying to wind it around. As a result, the center of the circumscribed circle at each cross-sectional position perpendicular to the longitudinal direction of the cord always exists on a substantially straight line, and the second wire bundle abnormally protrudes in the radial direction to form irregularities on the cord. The circumscribed circle diameter is prevented from becoming large, and a high rigidity can be realized while having a cord outer diameter substantially equal to that of the 1 × n structure.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows an example of a steel cord according to the present invention, in which (a) shows an enlarged side surface thereof, and (b) shows different sections in (a).
The steel cord A has a 3 + 2 structure with a first bundle 1 composed of three wires 10a, 10b, and 10c and a second bundle 2 composed of two wires 20a and 20b wound around the wire. All wires are drawn from high carbon steel and plated on the surface with good adhesion to rubber such as brass.
The wire diameter is preferably 0.20 to 0.45 mm. This is because the strength and rigidity are balanced. When the wire diameter is 0.20 mm or less, the tensile strength is good, but the rigidity is low. When the wire diameter is 0.45 mm or more, the rigidity is high, but the tensile strength is low.
[0008]
The wires 10a, 10b, and 10c in the first bundle 1 are not twisted with each other and are aligned in parallel. Similarly, the wires 20a and 20b in the second bundle are not twisted with each other and are aligned in parallel.
The first bundle 1 undulates so as to exhibit a gentle spiral shape as a whole, and the second bundle 2 is spirally wound around the outer periphery of the first bundle 1 in such a undulated state. ), The phase of the first bundle 1 changes so as to sequentially rotate around the center C of the cord, and the center C of the circumscribed circle D of each cross section exists on a substantially straight line CL. Accordingly, the diameter of the circumscribed circle D is almost the same at any cross-sectional position, and the diameter of the circumscribed circle is increased as a result of the wires of the second bundle 2 projecting in the radial direction, or the diameter of the circumscribed circle is increased. However, unevenness does not occur due to changes in the position of each surface. c is the center of the first bundle.
[0009]
Specifically, the undulation that exhibits the spiral shape is a continuous corrugation with the same wave height H on the top, bottom, left, and right of each of the wires 10a, 10b, and 10c as shown in FIGS. In addition, the vertical wave and the horizontal wave are shifted by a half pitch. 101 is a wave.
The wave pitch P of each wire is preferably 12.0 <P <20.00 mm. This is because if the wave pitch is too short, the productivity is lowered, and if it is 20.00 mm or more, the shape is close to a straight line, so that when the cord is used, the shape is easily broken and the shape retention is lowered.
The wave height H is preferably 0.70d <H <1.20d in relation to the diameter d of the wire. The reason is that if the wave height H is too low, the second bundle protrudes from the circumscribed circle to increase the unevenness of the cord, and if it is too high, the diameter of the circumscribed circle of the cord increases.
[0010]
FIG. 3 shows a second embodiment of the present invention. In this example, the first bundle 1 is composed of four wires, and the second bundle 2 is composed of two wires. Also in this case, in the cross section perpendicular to the longitudinal direction of the cord, the center C of the circumscribed circle lies on a substantially straight line CL.
[0011]
In the present invention, the number of wires of the first bundle 1 is selected from a range of 2 to 5. The number of wires in the second bundle is selected from a range of 1 to 3. The reason is that the rigidity is excessive when the number of wires of the first bundle 1 is six or more. Further, if the number of wires of the second bundle 2 is three or more, the cord structure becomes unstable.
In general, the number of wires in the first bundle 1 and the number of wires in the second bundle are preferably larger in the former than in the latter, but may be the same in some cases.
It is preferable that the wire diameters of the wires of the first bundle 1 and the second bundle are equal.
Moreover, at least one of the wires of the first bundle 1 may have a two-dimensional small wave from the viewpoint of rubber permeability.
[0012]
FIGS. 4 and 5 show a method of manufacturing the steel cord according to the present invention in one operation. In this example, a steel cord is composed of a first bundle of three wires and a second bundle of two wires. Shows when to do.
In FIG. 4, 3a, 3b and 3c are supply bobbins of the first bundle straight wires 100a, 100b and 100c, and 4 is a voice. On each wire path line between the voice 4 and the supply bobbins 3a, 3b, 3c, the first wave processing device 5 and the second wave processing device 6 are arranged 90 degrees out of phase.
[0013]
The first wave processing device 5 is arranged for forming a circular shape in which a pair of disks 51 and 51 are arranged close to each other in a radial direction on a frame 50 and can be meshed with each other at each peripheral position of the disks 51 and 51. A large number of elements 500 and 501 are arranged. The reason why the shaping elements 500 and 501 are circular is to draw a smooth curvature without the top of the wave being square, so that the shaping elements 500 and 501 can obtain the above-described wave pitch. A predetermined diameter is given, and the pushing amount is set so that the wave height can be obtained.
The shaping elements 500 and 510 may be capable of free rotation around their own axes by bearings.
The second wave processing device 6 has the same configuration as the first wave processing device 5, but the arrangement is changed by 90 degrees and is shifted by a half pitch from the pitch of the upper and lower waves formed by the first wave processing device 5. The position on the pass line is set so that the shaping elements 500 and 501 mesh with each other.
[0014]
7 is a buncher type stranding machine, which is a first guide roll 70 downstream of the voice 4, a second guide roll 71 on the opposite side, and a third guide roll 72 on the same side as the first guide roll 70. A fourth guide roll 73 on the same side as the second guide roll, a bow 74 between the first and second guide rolls, and a bow 75 between the third and fourth guide rolls, Supply bobbins 76 and 77 for the second bundle of wires are arranged, and a voice 78 for winding the second bundle around the first bundle is arranged downstream. 8 is a winding device downstream of the fourth guide roll.
[0015]
The straight wires 100a, 100b, 100c constituting the first bundle are guided to the voice 4 from the supply bobbins 3a, 3b, 3c, respectively, and are corrugated by the first wave processing device 5 and the second wave processing device 6 respectively. Is done. That is, when the first wave processing device 5 is reached, the shaping elements 500 and 501 on the outer periphery of the paired disks 51 and 51 are rotated so that they mesh with each other. Then, when the second wave processing device 6 is reached, since the shaping elements 500 and 501 on the outer circumferences of the paired disks 51 and 51 are rotated so as to be engaged with each other in a relationship where the phases are shifted by 90 degrees, The wires 10a ′, 10b ′, and 10c ′ corrugated in the vertical direction are waved in the left-right direction, for example, with the corrugation being shifted by a half pitch. As a result, each wire is shaped so as to form a spiral.
[0016]
The wires 10a, 10b, and 10c thus waved in the vertical and horizontal directions are collected in the voice 3 to form a bundle, and in this state, are guided to the second guide roll 71 through the rotating bow 74. Can be twisted. Then, while being guided from the second guide roll 71 through the cradle to the third guide roll 72, the wires are supplied around the first bundle from the supply bobbins 76 and 77 of the second bundle of wires. Then, the twist is returned during the period from the third guide roll 72 to the fourth guide roll 73.
Accordingly, as shown in FIG. 1, the cord is displaced so that the first bundle 1 spirals around the center C of the cord, and the second bundle 2 is wound around the cord, and the center of the circumscribed circle of each cross section C becomes a steel cord existing on a substantially straight line. The steel cord passes through the fourth guide roll 73 and is then wound around the winding device 8.
[0017]
【Example】
Examples of steel cords according to the present invention are shown in Table 1 together with conventional examples and comparative methods. All wires were manufactured using a high carbon steel wire containing carbon content C: 0.82%.
Examples 1, 2 and 3 were produced by the apparatus and method shown in FIGS.
Conventional Example 1 is one in which five strands are collectively twisted by a buncher type twisting machine. Conventional example 2 was manufactured by removing the corrugation device in FIGS. 4 and 5. The first bundle was assembled in the voice without any wave, and the twist was returned in-out with a buncher twister. It is a thing.
[0018]
[Table 1]

[0019]
In Table 1, the cord diameter is obtained by placing the cord on a plane and measuring the cord height from the plane. The cord diameter of Conventional Example 2 was also measured in the same manner.
“Rigidity” is a measurement of the bending moment when the steel cord is fixed at 100 mm intervals and the steel cord is bent so that the tangent of the fixing portions on both sides thereof is 15 °.
“Rubber permeability” is a result measured by a peeling method.
[0020]
As is apparent from Table 1, the rigidity of Examples 1, 2, and 3 is 14 to 15% higher than that of Conventional Example 1, and high rigidity substantially equal to that of Conventional Example 2 is realized. On the other hand, the cord diameter of the example is smaller than that of the conventional example 2 and is almost the same as that of the conventional example 1.
[0021]
【The invention's effect】
According to the present invention described above, in a steel cord having an N (N = 2 to 5) + M (M = 1 to 3) structure and the number of wires N ≧ M, the first wire bundles are not twisted together. The second wire bundle is wound around the bundle, and the center of the cord circumscribing circle is always on a substantially straight line in the cross section perpendicular to the cord longitudinal direction. The thickness of the rubber composite when it is embedded in a rubber sheet such as a belt layer, while suppressing the protrusion of the bundle and having a high rigidity yet a cord diameter smaller than the same number of 1 × n or n + m cords It is possible to reduce the thickness of the tire and to obtain lightweight radial tires with good ride comfort and handling stability. In particular, the first wire bundle has the same height in the vertical and horizontal directions. The corrugation pitch of the upper and lower sides and the right and left is constituted by a half pitch phase shift. The wave pitch of each wire is 12.0 <P <20.00 mm, and the corrugation height is 0.70d < Since H <1.20d (d is the diameter of the wire mm), it is possible to obtain an excellent effect that the rigidity can be improved and the outer diameter of the cord can be reliably reduced.
[Brief description of the drawings]
FIG. 1 (a) is an enlarged side view showing an example of a steel cord according to the present invention, and FIG. 1 (b) is aa, bb, cc, dd, ee in (a). It is sectional drawing of each position.
2A is a side view of a first bundle of wires according to the present invention, FIG. 2B is a plan view thereof, and FIG. 2C is a front view thereof.
FIGS. 3A to 3D are cross-sectional views of another example of a steel cord according to the present invention cut at different positions.
FIG. 4 is an explanatory view schematically showing a steel cord manufacturing apparatus and manufacturing method according to the present invention.
5 is a detailed view of a wave machining device portion in FIG. 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st bundle 2 2nd bundle 10a, 10b, 10c 1st bundle of wires 20a, 20b, 20c 2nd bundle of wire C Code center CL Code center line D Code circumscribed circle 101 Wave

Claims (1)

In a steel cord having an N (N = 2 to 5) + M (M = 1 to 3) structure and the number of wires N ≧ M, the first wire bundles are gathered together without being twisted together and are continuous in the longitudinal direction as a whole. The second wire bundle is wound around this bundle, the center C of the circumscribed circle of the cord is always in a substantially straight line in the cross section perpendicular to the longitudinal direction of the cord, and the first wire bundle is The vertical and horizontal corrugations are corrugated at the same height, and the vertical and horizontal corrugation pitches are configured by a half-pitch phase shift. The wave pitch of each wire is 12.0 <P <20.00 mm. A high-strength steel cord for reinforcing rubber, wherein the corrugation height is 0.70d <H <1.20d (d is the diameter of the wire mm).

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