KR100264408B1 - Wire rope having an independent wire rope core - Google Patents

Abstract

(여기서, T1은 접촉단면의 원주 성분의 길이를 표시하며, C는 코아 로우프의 외접원의 원주의 길이를 나타냄)이며, 비접촉율

(여기서, 여기서 n은 가닥의 수를 표시함)은 코아 로우프의 외접원 원주의 20% 이하이다.The wire rope comprises a core rope each having a plurality of strands of a plurality of wires and a plurality of outer strands wrapped around the core rope. Each strand of the core rope has a contact section in contact with the outer strand in which two or more wires of the core rope strand are wrapped. Overall contact section rate

(Where T1 denotes the length of the circumferential component of the contact section, and C denotes the length of the circumference of the circumferential circle of the core rope).

Where n represents the number of strands is less than 20% of the circumferential circumference of the core rope.

Description

Wire rope with separate wire rope cores

The present invention relates to a wire rope having a wire rope, in particular a separate wire rope core (hereinafter referred to as "core rope"), which is suitable as a driving rope.

Drive ropes require high strength and high flexibility. As such a drive rope, so-called IWRC rope has generally been used. IWRC wire ropes use an independent wire rope core (IWRC) with a given number of strands wrapped around.

The verb “strand” in this specification means “twisting multiple wires into one strand” and “close” means “twisting multiple strands into one wire rope”. to be.

5 (a) to 5 (d) show the construction of a typical IWRC wire or IWRC 6 × Fi (25) JIS Type-14. This IWRC wire rope comprises one core rope 11 and six outer strands 14. Each outer strand 14 comprises one center wire, six intermediate wires, six filling wires and twelve outer wires. As shown in FIG. 5 (a), in particular the core rope 11 is formed by seven twisted strands 12, each strand having seven twisted wires 13. Six outer strands 14 surround the core rope 11. These IWRC wire ropes are used as drive ropes for use in construction machinery, cranes, oil well drilling machines, and the like.

However, the conventional IWRC wire rope has the following problems. In operation, the outer strand 14 and the core rope 11 are in friction with each other and the wires of the outer strand 14 or the core rope 11 resemble or bend so that the wire is finally broken. To this. In addition, when a high tensile force or other external force is applied to the wire rope, the strands 12 of the core rope 11 or the wires 13 of the strands 12 are changed from one another by heavy loads, and the outer strands 14 ) Moves into the space between the strands of the core rope 11, resulting in cutting of the wire or deformation of the core rope 11. These problems inevitably reduce the life of the wire rope.

The following can be considered as the cause of this problem. As shown in FIG. 5 (a), the core rope 11 formed by seven strands 12 twisted with seven twisted wires 13 each has six vertex shapes in its cut state. (vertex-like) protrusions and six large recesses. As shown in FIG. 5 (b) and FIG. 5 (d), the outer strand 14 twisted around the core rope 11 is in point contact with the core rope 11. When a large load acts on the wire rope, the peaked protrusion or outermost wire 13 of the strand 12 is subjected to the largest load. Furthermore, the core rope 11 has a large recess in its outer circumference. Therefore, the strands 12 and the wire 13 are moved between each other due to the large load, the outer strand 14 is consequently moved into the recess between the strands 12, as shown in Figure 5 (c) . In addition, the strands 12 constituting the core rope 11 generally have a rounded cross section, and the wires 13 constituting the strand 12 have a generally rounded cross section so that they are easy to move.

In view of these problems in typical IWRC wire ropes, there is an urgent need for new IWRC wire ropes with longer resistance and high resistance to damage such as cutting and deformation of wires.

It is an object of the present invention to provide a wire rope that solves the problems of the prior art.

According to one aspect of the present invention, there is provided a core rope comprising: a core rope comprising a predetermined number of strands each having a predetermined number of wires; A wire rope is provided that includes a predetermined number of outer strands twisted on the core rope; Here, each strand of the core rope has a flat outside to provide a contact cross section when two or more wires of the strand come into contact with the stranded outer strand.

According to another aspect of the present invention, there is provided a method comprising: twisting a predetermined number of wires and flexible core members into strands; Twisting a certain number of strands with core rope; Twisting a certain number of wires into the outer strands; Reducing the diameter of the core rope such that at least two respective strands of the core rope can act in contact with the outer strand; A wire rope manufacturing method is provided that includes twisting a predetermined number of outer strands into a core rope of reduced diameter.

In the wire rope thus constructed, the stranded outer strands come into contact with two or more wires of each strand constituting the core rope. Therefore, the strand of the core rope can stably contact or support the stranded outer strand more stably than the normal wire rope in which the single wire of the strand constituting the core rope contacts the stranded outer wire, thereby preventing the movement of the wire or strand. .

Moreover, the extended contact cross section more reliably prevents the outer strands from moving into the spaces between the strands of the core rope by large loads.

The above objects, features and advantages of the present invention and other objects, features and advantages will become more apparent by reading the following detailed description and the accompanying drawings.

1 (a) is a sectional view of an IWRC wire rope according to the present invention.

Fig. 1 (b) is a cross-sectional view of the core rope for IWRC wire rope before the diameter is reduced.

Fig. 1 (c) is a cross-sectional view of the IWRC wire rope core rope after the diameter is reduced.

Figure 2 (a) is a view showing a state of contact between the core rope and the outer strand is not reduced in diameter.

Figure 2 (b) is a view showing a state of contact between the core rope and the outer strand is reduced in diameter.

Figure 3 (a) is a developmental view in the longitudinal direction showing the contact state between the core rope and the outer strand of reduced diameter in the IWRC wire rope of the present invention.

Figure 3 (b) is a cross-sectional view showing the contact state between the core rope and the outer strand of reduced diameter in the IWRC wire rope.

4 (a) to 4 (c) are diagrams showing the relationship between strands constituting a reduced core rope, individual contact cross-section and individual non-contact cross-section.

4 (d) is a graph showing the relationship between the total contact cross section, the non-contact cross section and the number of strands of the core rope serving as a parameter.

Figure 5 (a) is a cross-sectional view of a conventional IWRC wire rope.

FIG. 5 (b) shows the contact between core rope and outer strands in a conventional IWRC wire rope.

FIG. 5 (c) shows another contact between core rope and outer strands in a conventional IWRC wire rope.

5 (d) is a view in which the contact between the core rope and the outer strand in the conventional IWRC wire rope is developed in the longitudinal direction.

Preferred embodiments of the invention are described with reference to the drawings. Figure 1 (a) shows an IWRC wire rope implementing the present invention. FIG. 1 (b) shows the core rope of which the diameter of the IWRC wire rope is not reduced, and FIG. 1 (c) shows the IWRC core rope of which the diameter is reduced.

The IWRC rope is IWRC 6 × Fi (25) JIS Type-14, and is formed by twisting six outer strands 5 on the core rope 1. The core rope 1 consists of four strands 2 twisted together. Each strand 2 consists of one fiber core 4 and seven wires 3 twisted in the fiber core 4. Each outer strand 5 consists of one center wire, six intermediate wires, six filling wires and twelve outer wires.

The core rope 1 twists four strands to form the initial core rope 1 ', and then the diameter of the initial core rope 1' as shown in the first (b) and 1 (c) diagrams. Is made by compressing the outside of the twisted four strands (2) to reduce from D to d. This reduction in diameter brings the outer surface of the strand 2 closer to the circumscribed circle of the core rope 1.

In particular, as shown in FIG. 2 (a), the core rope 1 ′ and the outer strand 5 when the outer strands 5 are enclosed in an initial core rope 1 ′ whose diameter is not reduced. Are in contact with each other at points P along the circumscribed circle of the initial core rope 1 '. However, when the outer strands 5 are enclosed in the core rope 1 having a reduced diameter as shown in FIG. 2 (b), the core rope 1 and the outer strand 5 are the core rope 1. In contact with each other (Tz) extending along the circumscribed circle of. In other words, two or more wires 3 of the strands 2 come into contact with the outer strands 5 twisted at the contact end face Tz. In summary, the former is in point contact while the latter is in line contact. Thus, the core rope 1 is in contact with the outer strands 5 at an increased area and is subjected to a reduced load per unit area because the load is distributed over a larger area.

FIG. 3 (a) is an exploded view showing the contact state between the four strands 2 and the six outer strands of the core rope 1 having a reduced diameter. This figure clearly shows that the strands 2 and the outer strands 5 are in contact with each other over a considerable length (contact section T) in the longitudinal direction of the wire rope. The non-contact cross section through which the core rope 1 cannot contact the outer strand 5 is indicated by G. It can be seen that the contact cross section T is significantly wider than the non-contact cross section G.

In other words, as shown in FIG. 3 (b), as the outer surface of the strand 2 becomes closer to the circumscribed circle, the recesses between the strands 2 become smaller, and the non-contact section G becomes smaller. The spacing between each support point of the adjacent strands 2 also becomes smaller. This in turn reduces the bending stress at the outer strands 5 and also prevents the outer strands 5 from moving into the recesses between the strands 2.

Furthermore, the reduction in diameter not only changes the cross section of each strand 2 from circular to a substantially triangular shape, but also makes the internal space of the core rope 1 smaller. As a result, even if a large load is applied, sliding movement between the individual strands 2 and the wires 3 of the strands 2 is reduced, thus reducing the possibility of the outer strands 5 moving to the recesses between the strands 2. Let's do it. In this way, the pressure on the wire is reduced by preventing the movement of the outer strand into the recess, and wear on the wire is reduced by preventing the movement of the wire and the strands, thereby preventing breakage of the wire or irregularities of the rope shape. do.

The contact state between the core rope 1 and the outer strand 5 is determined by the ratio of the length of the contact section to the circumference of the circumscribed circle of the core rope 1 or the inscribed circle of the outer strand 5 as follows.

In FIG. 2 (b), the contact cross section defined by equation (1) is represented by Tz.

Here, T1 denotes the length of the circumferential component of the contact cross section, and C denotes the circumferential length of the circumscribed circle of the core rope 1 or the inscribed circle of the enclosed outer strand 5.

In addition, the non-contact sectional rate defined by Formula (2) is represented by Gz.

Where n represents the number of strands.

4 (a) to 4 (c) show the relationship between the number of strands (n), the contact cross section (Tz) and the non-contact cross section (Gz) constituting the core rope of which diameter is reduced.

As shown in FIGS. 4 (a) to 4 (c), the contact cross section Tz and the non-contact cross section Gz vary depending on the number of strands of the reduced core rope, even if the diameter is equally reduced. 4 (d) is a graph showing the relationship between the total contact cross section ratio Tz, the noncontact cross section ratio Gz, and the number of strands n of the core rope serving as a parameter.

When the number of strands is small, for example n = 3, the non-contact cross-section is relatively high, for example higher than 27%, even if the overall contact cross-section is, for example, lower than 20%. The higher the non-contact section ratio, the larger the spacing between the supports of adjacent strands, which in turn increases the bending stress at the outer strands and also increases the likelihood of breakage of the outer strands.

Therefore, the conditions for obtaining the above-mentioned advantageous effects of the core rope having a reduced diameter can be determined by terms of the total contact cross section and the non-contact cross section. In particular, the overall contact cross-sectional rate is 20% or more, and each non-contact cross-sectional rate may be preferably 20% or less.

Next, the characteristic of the IWRC wire rope of this invention is demonstrated in detail compared with the conventional IWRC wire rope.

The IWRC wire rope of the present invention was made as follows. As shown in Figure 1 (b), the initial core rope 1 'is made by twisting four strands with one fiber core 4 and seven wires 3, respectively. The initial core rope 1 'has a diameter of 5.8 mm. The initial core rope 1 'passed through a die to form a core rope 1 having a diameter of 5.4 mm as shown in FIG. 1 (c). It is also possible to reduce the diameter of the core rope by swaging. The six outer strands 5 are then twisted around the core rope 1 to form a wire rope having a diameter of 14.7 mm and a rope pitch of 87 mm. The outer strand 5 has one center wire, six intermediate wires, six filling wires and twelve outer wires.

The reduction die has a reduction rate of about 13%. The reduced core rope 1 has a total cross-sectional contact ratio Tz of about 56% and a non-contact cross-sectional ratio Gz of about 11%. The wire rope of the present invention has a breaking strength of 137 kN.

Meanwhile, as a comparative example, a conventional IWRC wire rope having the same diameter (= 14.7 mm) and the same rope pitch (= 87 mm) was manufactured. However, this comparison wire rope has a core rope 11 as shown in FIG. 5 (a) and does not have a core rope 1 with a reduced diameter as shown in FIG. 1 (a). . This comparative wire rope has a breaking strength of 141 kN.

The following bending fatigue test was performed on the fabricated inventive and conventional IWRC wire ropes.

Diameter of rope pulley for bending test: 240 mm

-Ratio of bending diameter to rope diameter: 18

Tensile force on rope: 27 kN

Factor of safety: 5

-Bend form: S bend

Contact angle: 180 ° × 2

Stroke: 1,200 mm

Number of bends: 12,000

Table 1 shows the number of cut wires and Table 2 shows the diameter of the wire rope before and after the test.

It can be seen from Table 1 that the wire rope of the present invention is superior to the comparison wire in terms of the number of cutting wires and the cutting position. In particular, it can be seen that the wire rope of the present invention is remarkably superior to the comparison wire rope in terms of the cutting position, i.e. the number of cut wires of the wire rope of the present invention in the core and inner wire of the outer strands is comparable. Is much less than the number of cut wires.

In addition, it can be seen from Table 2 that the diameter reduction of the rope of the present invention is smaller than the diameter reduction of the comparison wire rope not only under the unloaded condition but also under the loaded condition.

Therefore, it can be concluded that the wire rope of the present invention has excellent resistance to wire cutting and wire movement.

The above embodiment is a core rope having four strands each consisting of one fiber core and seven wires, and six cores each consisting of one center wire, six intermediate wires, six filling wires and twelve outer wires. An IWRC 6 × Fi (25) JIS Type-14 wire rope comprising an outer strand. However, the present invention is not limited to the IWRC 6 × Fi (25) JIS Type-14 wire rope, and the outer surface of the strands constituting the core rope is in close contact with the circumferential circle of the core rope, thereby increasing the contact cross section and reducing the non-contact cross section. It can be applied to various kinds of wire rope as long as the diameter of core rope can be reduced.

Moreover, the present invention produces new wire ropes with higher strength and flexibility by changing the core rope configuration, e.g. wire diameter, number of wires, number of strands, diameter reduction rate, to increase the contact cross-section. Makes it possible.

It should be noted that the diameter reduction rate of the above-described embodiment is exemplified as a preferred example in consideration of the number of strands. According to the present invention, the advantages of the present invention can be obtained as long as the reduction ratio of the diameter ensures an overall contact cross-sectional ratio of 20% or more. However, in order to keep the bending stress of the outer strands small, especially when the number of strands of the core rope may be desirable to adjust the diameter reduction rate so that the specific contact ratio (Gz) is 20% or less.

Moreover, in the above embodiment, the fiber core 4 is used as the center of the strand 2 of the core rope 1. However, according to the present invention, other materials besides fiber cores can be used as the center of the strand, for example, fiber ropes and rubber cores as long as the diameter thereof can be reduced so that the diameter thereof can be reduced.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, various modifications and adaptations will be readily apparent to those skilled in the art. Therefore, it will be understood that such variations and modifications are included in the present invention unless they depart from the scope of the present invention.

Claims (4)

A core rope comprising a plurality of strands each having a plurality of wires; A plurality of outer strands enclosed over the core rope; Wherein each strand of the core rope has a flat exterior that provides a contact cross section when two or more wires contact the stranded outer strand. The wire rope according to claim 1, wherein the core rope has a plurality of strands in total contact cross section in a state in which a total contact cross section ratio Tz defined by the following formula (1) is 20% or more of the circumferential circumference of the core rope.

Here, T1 denotes the length of the circumferential component of the contact section, and C denotes the circumferential length of the core rope circumscribed circle. 3. The core rope does not come into contact with the outer strand in which the core rope strands are twisted under the condition that the non-contact cross section Gz defined by the following formula (2) is 20% or less of the circumferential circumference of the core rope. Wire rope with non-contact cross section.

Where n represents the number of strands. Stranding a plurality of wires and a flexible core member; Twisting the plurality of strands into core rope; Twisting the plurality of wires into one outer strand; Reducing the diameter of the core rope such that at least two respective strands of the core rope can operate in contact with the outer strand; A method of making a wire rope comprising twisting a plurality of outer strands in a reduced core rope.

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