JPS591790A - Steel cord - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly applies to hard filaments used as tire reinforcing materials.
This is a book about steel cords composed of multiple i-wires.

Generally, this type of steel cord is made up of a single wire or a plurality of twisted wires. A plurality of these steel cords are then lined up in parallel and covered with a rubber material to be used as a reinforcing material for tires.

Thus, when a steel cord is used as a reinforcing material, the essential requirements are good adhesion with the chemical Nicom material and good penetration of the rubber material into the interior of the steel cord. In other words, in order for the steel cord to fully fulfill its role υ as a reinforcing material, it is necessary that the steel cord and the rubber material form a complete composite.

However, as shown in FIGS. 1(A), 2(B), and 1(C), conventional steel cords are constructed by twisting a plurality of wires 2 or strands 5 together.

The above steel cord 1 has each strand 2 or strand 3
When the comrades are piled up and covered with a rubber material, the rubber material will not penetrate into the space inside the steel cord 1, and a space A will be created inside the steel cord 1 where no rubber will penetrate.
There was a drawback that the rubber material did not wrap around the entire circumference of the wire 2 or strand 3, resulting in insufficient adhesion to the rubber.

For this reason, recently, steel cords have been considered in which the rubber material penetrates up to the inside S of the steel cord and the rubber material adheres to the entire circumference of the strands.

This steel cord is as shown in Figure 2 B) (B).
Each element I! This is a steel cord 1 with a soft twist, which is twisted together with a gap t't between the two.

However, even if the above-mentioned steel cord achieves the purpose of rubber infiltration, it is not easy to twist, as shown in Fig. 3.
As shown in Figure 2, the initial elongation of the cord under tension at low loads is larger than in Figure a, the apparent modulus of elasticity at low loads is extremely small, and the elongation rate changes sequentially with changes in load, making workability extremely difficult. It has the disadvantage of being bad. In other words, in tire molding work, when hundreds of steel cords aligned with σ1 are fed out in the calender sheeting process, it is difficult to keep the initial elongation of each steel cord constant using normal tension control, so it is difficult to keep the initial elongation of each steel cord constant. After the steel cord is coated and the tension is loosened, the amount of contraction of the steel cord becomes unbalanced, which impairs the smoothness of the calender sheet, which greatly impedes the quality and workability of the tire. Also, the tension applied to each steel cord causes a kink change due to the loose tension. This has the drawback that when the sheet is cut after being coated with a rubber material, the cut end springs up or twists, which is a major hindrance to the recent automation that requires precision of the sheet.

The present invention was made in order to eliminate the above-mentioned drawbacks, and by arranging a core wire with a high elastic modulus strand, a hot wire, or an untwisted wire bundle, the initial elongation under low load is minimized,
Provides a steel cord that improves workability and improves fatigue resistance by arranging solid wires or twisted hard steel wires on the outside almost concentrically so that they do not touch each other to prevent rubber penetration. It is something to do.

That is, the present invention constructs an open cord by twisting three or more single wires or strands so that they are located on substantially concentric circles with gaps between them, and inside the open cord, there is no contact with the open cord as a general rule. , the elastic modulus is higher and the breaking strength is lower than that of the open cord, and if necessary, the elastic modulus is 65001 f/- or more, and the breaking strength is 2% or more and 20% of the breaking strength of the open cord. This steel cord is characterized by having core wires such as solid wires, twisted wires, or untwisted wire bundles arranged therein.

An embodiment of the present invention will be described below based on the drawings. Figures 4(a), (b), and (c) are cross-sectional views showing embodiments of the steel cord of the present invention, and FIG. 5(b) is a sectional view of the steel cord of the present invention. FIG.

Example 1 As shown in Fig. 4 K) and Fig. 5, five strands Is2 each having a diameter of 0.25 strands were put into a twisting machine and twisted while combing each strand 2. A soft open cord with a twist configuration of 1 x 5 x 0.25 is formed, and at the same time as the formation of this open cord, the core @4 is formed ([lL17
5M elastic modulus 21000 rf/a+2, breakage strength cuff K
IXo, 175+5X0.
25 steel cords 5 are formed.

Example 2 As shown in Fig. 4, the lX6
Form a sweet open cord of X0.3B, core @4
The breaking strength is 28, and the elastic modulus is 6s o o Q/rn.
Glass fiber 115o-4/24.0z with m2 (
1 +6XOj using
8 steel cord 5 is formed.

Example 6 As shown in FIG. 4(C), a 4 x 4 x O, 22 sweet open cord was formed using the strand 3 in the same manner as in Example 1, and the core [4] was 17
KF' - 1+4 using aramid 1000 d/1'fc with modulus 12000Q/7ftm2 t-
Form a steel cord of X4X0.22.

In each of the above embodiments, the number of open cords that constitute the open cord is 6 or more that requires a gap between each other, and the upper limit of the number may be any number depending on the properties of the target steel cord, but experimentally 4~ Nine is the most economically practical.

In addition, the flat gap t between the single wires or strands constituting the open cord is determined to facilitate the penetration of rubber, and the lower limit is determined from the vulcanization conditions and rubber quality of the rubber.
The upper limit can be determined freely as it has been improved to prevent workability from being hindered by excessive elongation at low loads, as with conventional Amayoshi open cords, but in reality it depends on the thickness of the core and the side cords. The decision was made based on the number of wires, the apparent diameter of the hood, and the workability of the twisting process! 11.0.015m5-0.04MtM degree is suitable.

Keep in mind that whether the core wire is a solid wire, stranded wire, or untwisted wire bundle depends on the material, core thickness, and strength settings.
However, when glass or special, organic, or inorganic fibers are used, twisted wires or #i untwisted wire bundles are used, and when metal is used, single wires are appropriate from the economic point of view. However, in the case of thick steel cords, gold) jt4 is used to maintain its flexibility.
! [J stranded wire may be used in some cases.

The material of the core wire is important for suppressing initial elongation under low load, and the elastic modulus must be at least 6500/mytr2 or more. In addition, it fits in the limited space in the center of the open cord, and the 2 to 20
% breaking strength, suitable materials include steel wire, fiberglass, aramid, carbon fiber, and amorphous alloys; conventional organic fibers such as polyester, polyamide, and rayon are unsuitable.

Next, the breaking strength of the core wire is 2 times the breaking strength of the open cord.
~20% is appropriate. That is, since most of the tension applied during normal steel cord handling operations is applied to the core due to the large difference in apparent modulus of elasticity, it is necessary to apply a lower limit to the core so that it does not break with such force.

In addition, due to the function of the core, higher breaking strength is desired in order to reduce the elongation deformation during initial loading, but from the viewpoint of actual workability, the desired level is to reduce the initial elongation by about 1/2. For this purpose, a chord strength of 20- is sufficient.

Also, even if you want more than this, it will be difficult to place the core without touching the wire oven cord, which has a large diameter.
There is a risk that the steel cord will lose its flexibility.

The steel cord of the present invention and the first
Comparison examples with the conventional steel cord shown in Figure 2) and the conventional soft twisted open cord shown in Figure 2 are shown in Table 0. The steel cord has the advantages that the conventional slightly twisted open cord has over the conventional steel cord, that is, it maintains the penetrability and fatigue resistance of the rubber material, and it also has the advantage of maintaining the penetrability and fatigue resistance of the conventional soft twisted open cord. The elongation rate due to the initial load, which was the biggest drawback of the previous model, has been greatly reduced, and at the same time, the change in kink has been suppressed.
It has the excellent effect of solving problems such as smoothness, twisting, and bulging of the cut edges of the calendar sheet that occur during the calendar sheet making process.

[Brief explanation of the drawing]

Figure 1 B) (B) and (C) are cross-sectional views showing conventional tightly twisted steel cords, and Figure 2 (A) and (B) respectively.
(C) is a cross-sectional view showing the conventional twisted steel cord, FIG. 3 is a curve diagram showing the relationship between tensile load and initial elongation, and FIG. FIG. 5 is a side view of No. 5NK). 2...Elementary wire 3...Strand 4...Core wire Patent applicant Hiroshi Kanai, agent Kiyoshi Hayashi',',l・Moe,）゛ShiSom・% Figure C'r )
(1 ml Figure 8 Procedural Amendment LP Layer 4 G-I October 22, 1920 Showa G, Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1 To Gansho Temple/-/Tsume θ 2, Invention Name Steel Code 3, Relationship with the person making the amendment Patent applicant Address 21-6 Higashiyama-cho, Ashiya City, Hyogo Prefecture Name Hiroyuki Kanai 4, Agent Showa (July 78, 1976, 6, Inventions increased by amendment) Number (1) Specification No. 11, lines 11 to 18 (last page)
) amend the brief description of the drawing as follows. [4. Brief explanation of the drawings

Claims (1)

[Claims] (1) An open cord is constructed by twisting six or more single wires or strands so that they are located on concentric circles with gaps between each other, and the above-mentioned open cord is formed inside the cord. It is characterized by having a core wire such as a single wire, a twisted wire, or an untwisted wire bundle, which is in contact with the cord as a general rule, and has physical properties such as a higher elastic modulus and lower breaking strength than the open cord. Steel cord. ) As a core wire, the elastic modulus is 6500 Kl/Ijd or more, the breaking strength is 2 times the breaking strength of the open cord, and the breaking strength is 2
The steel cord according to claim 1, characterized in that the steel cord has physical properties of ~20%. (3) Claims tffi characterized in that the open cord is constituted by a strand having a long-gauge cord formed by twisting a plurality of strands together.
@ Steel cord described in item 1. (4) 8I as a core wire! , 7 eyeglass, aramid, carbon fiber, or an amorphous alloy.