Steel wire rope for tire belt reinforcement

Abstract

The present invention relates to a steel cord for reinforcing a tire belt, characterized in that it comprises a cord formed by n wires twisted periodically, said n wires being compressed by calendering, said wires being compressed by calendering and at least one of said n wires being compressed into a non-circular shape, wherein, when n is odd, the cross section of one of said n wires is circular due to the calendering and the cross section of n-1 wires is non-circular, and when n is even, the cross section of two of said n wires is circular due to the calendering and the cross section of n-2 wires is non-circular.

Description

Technical Field

[0001] The present invention relates to a steel wire rope for reinforcing tire belt layers, and more specifically, to a steel wire rope for reinforcing tire belt layers, wherein a rope formed by periodically twisting n wires is rolled to produce wires having circular and non-circular cross-sections, and the number of wires having circular cross-sections varies depending on the number of wires. Background Technology

[0002] Among the various reinforcing materials used to strengthen various rubber products, including vehicle tires and industrial belts, steel cord used for tire reinforcement possesses excellent properties such as strength, modulus, heat resistance, fatigue resistance, and rubber adhesion. Based on these properties, steel cord is widely used as a tire reinforcement material to meet the required functions of tires, and its usage is showing a continuous increasing trend.

[0003] With the world significantly tightening regulations on CO2 emissions, there has been a rapid shift towards electric vehicles. In the case of electric vehicles, energy consumption is high due to tire rotational resistance, necessitating the development of a steel cable that can reduce this resistance.

[0004] In addition, in order to reduce CO2 emissions, it is necessary to improve tire life, so a steel wire rope that can improve tire durability, fatigue characteristics and other properties is needed. Summary of the Invention

[0005] Technical issues

[0006] The present invention addresses the aforementioned problems, and more specifically, relates to a steel wire rope for reinforcing tire belt layers, wherein a rope formed by periodically twisting n wires is rolled to produce wires with circular and non-circular cross-sections, and the number of wires with circular cross-sections varies depending on the number of wires.

[0007] Technical solution

[0008] To solve the above problems, the present invention for reinforcing tire belt layers is characterized by comprising a rope formed by periodically twisting n wires, the n wires being compressed by a rolling process, wherein at least one of the n wires is compressed into a non-circular shape, wherein when n is odd, the cross-section of one of the n wires is circular due to the rolling process, and the cross-section of n-1 wires is non-circular; when n is even, the cross-section of two of the n wires is circular due to the rolling process, and the cross-section of n-2 wires is non-circular.

[0009] In the steel wire rope for reinforcing the tire belt layer of the present invention, which aims to solve the above-mentioned problems, when a wire whose cross-section is circular due to rolling is referred to as a first wire, and a wire whose cross-section is non-circular due to rolling is referred to as a second wire, the value of the minor axis of the second wire relative to the diameter of the first wire can be from 0.70 to 0.98.

[0010] To solve the above problems, the number (n) of the wire rope for reinforcing the tire belt layer of the present invention can be 3 to 9.

[0011] To solve the above problems, the diameter of the first wire of the steel wire rope for reinforcing the tire belt layer of the present invention can be from 0.1 mm to 0.6 mm.

[0012] In the steel wire rope for reinforcing tire belt layers of the present invention, which aims to solve the above-mentioned problems, when the diameter of the wire before rolling is referred to as d (mm), the first strength (normal tensile strength, NT) can be defined as 3,200-2,000×d (mm) ± 200 (MPa), the second strength (high tensile strength, HT) can be defined as 3,500-2,000×d (mm) ± 200 (MPa), the third strength (very high tensile strength, ST) can be defined as 3,850-2,000×d (mm) ± 200 (MPa), the fourth strength (ultra tensile strength, UT) can be defined as 4,200-2,000×d (mm) ± 200 (MPa), and the fifth strength (mega tensile strength, Mega Tensile Strength) can be defined as 4,200-2,000×d (mm) ± 200 (MPa). Tensile (MT) is defined as 4,600-2,000 × d (mm) ± 200 (MPa), wherein the tensile strength of the wire prior to calendering can have any one of the second strength, the third strength, the fourth strength, and the fifth strength.

[0013] In the steel wire rope for reinforcing the tire belt layer of the present invention, which aims to solve the above-mentioned problems, the wire having a tensile strength of the nth strength before calendering can be processed by calendering to have a tensile strength of the (n-1)th strength.

[0014] Beneficial effects

[0015] This invention relates to a steel wire rope for reinforcing tire belt layers, wherein the steel wire rope is manufactured by rolling, which can improve rigidity in the direction of tire rotation axis, thereby having the advantage of improving the durability and fatigue characteristics of the steel wire rope.

[0016] In addition, the present invention improves the permeability of the rubber through calendering, thereby preventing the durability of the wire rope from deteriorating due to the penetration of moisture or salt. Furthermore, by improving the permeability of the rubber, the present invention enhances the initial adhesion of the wire rope.

[0017] Furthermore, the present invention manufactures steel wire ropes through calendering, thereby having the advantage of reducing the thickness of the rubber when embedding the steel wire rope into the rubber sheet. Attached Figure Description

[0018] Figure 1 The diagram illustrates a steel wire rope with two circular cross-sections when n is an even number, as shown in the embodiment of the invention.

[0019] Figure 2 The diagram illustrates a steel wire rope with a circular cross-section when n is odd, as shown in an embodiment of the invention.

[0020] Figure 3 A diagram illustrating the short axis according to an embodiment of the present invention.

[0021] Figure 4 A diagram of the first and second lines is shown for an embodiment of the present invention when n is 6.

[0022] Figure 5 According to embodiments of the present invention, the conditions of Examples 1, 2, and 3 are shown where the value of the minor axis d2 of the second line relative to the diameter d1 of the first line is in the range of 0.70 to 0.98 when n is odd, and the conditions of Comparative Examples 1, 2, and 3 where the value of the minor axis d2 of the second line relative to the diameter d1 of the first line exceeds the range of 0.70 to 0.98.

[0023] Figure 6 To show that Figure 5 A graph comparing the initial adhesion of Comparative Examples 1, 2 and 3 with that of Examples 1, 2 and 3.

[0024] Figure 7 To show that Figure 5 A graph comparing the fatigue cycles of Comparative Examples 1, 2, and 3 with those of Examples 1, 2, and 3.

[0025] Figure 8 According to embodiments of the present invention, the conditions of Examples 1, 2, and 3 are shown where the value of the minor axis d2 of the second line relative to the diameter d1 of the first line is in the range of 0.70 to 0.98 when n is an even number, and the conditions of Comparative Examples 1, 2, and 3 where the value of the minor axis d2 of the second line relative to the diameter d1 of the first line exceeds the range of 0.70 to 0.98.

[0026] Figure 9 To show that Figure 8 A graph comparing the initial adhesion of Comparative Examples 1, 2 and 3 with that of Examples 1, 2 and 3.

[0027] Figure 10 To show that Figure 8 A graph comparing the fatigue cycles of Comparative Examples 1, 2, and 3 with those of Examples 1, 2, and 3.

[0028] Figure 11 According to embodiments of the present invention, the straightness of Examples 1 and 2 is shown in which the value of the minor axis d2 of the second line relative to the diameter d1 of the first line is in the range of 0.70 to 0.98, and the straightness of Comparative Examples 1 and 2 is shown in which the value of the minor axis d2 of the second line relative to the diameter d1 of the first line exceeds the range of 0.70 to 0.98. Detailed Implementation

[0029] This specification clarifies the scope of the invention, explains the principles of the invention, and discloses embodiments, enabling those skilled in the art to implement the invention. The disclosed embodiments can be implemented in various forms.

[0030] Expressions such as "comprising" or "may include," which may be used in various embodiments of the invention, indicate the presence of a corresponding function, operation, or constituent element of the invention, but do not limit the addition of one or more additional functions, operations, or constituent elements. Furthermore, in various embodiments of the invention, terms such as "comprising" or "having" should be understood as intended to indicate the presence of features, numbers, steps, operations, constituent elements, components, or combinations thereof described in the specification, and do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, constituent elements, components, or combinations thereof.

[0031] When a component is described as "connected and combined" to another component, the component can be directly connected or combined to the other component, but it should be understood that another new component can also exist between the component and the other component. Conversely, when a component is described as "directly connected" or "directly combined" to another component, it should be understood that another new component does not exist between the component and the other component.

[0032] Terms such as “first” and “second” used in this specification may be used to describe various constituent elements, but the constituent elements are not limited by the terms. The terms are only used to distinguish one constituent element from another.

[0033] This invention relates to a steel wire rope for reinforcing tire belt layers, wherein a rope formed by periodically twisting n wires is rolled to produce wires with circular and non-circular cross-sections, and the number of wires with circular cross-sections varies depending on the number of wires.

[0034] The wire rope according to embodiments of the present invention can be used to reinforce the tire belt layer of a vehicle, and can also be used as another component when needed. Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings.

[0035] Reference Figure 1 and Figure 2 According to an embodiment of the present invention, the steel wire rope for reinforcing the tire belt layer includes a rope 110 formed by periodically twisting n wires 120.

[0036] The rope 110 is formed by periodically twisting n wires 120, and the number (n) of the wires 120 is preferably 3 to 9. The steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention is manufactured by rolling the rope 110, which is formed by periodically twisting n wires 120.

[0037] The n wires 120 can be positioned within a virtual first circle 130 where they contact each other before the rolling process. For example... Figure 1 and Figure 2 As shown, n lines 120 are set in a virtual first circle 130 where the n lines 120 are in contact at the same time, and then rolling processing is performed.

[0038] When the n wires 120 are compressed by calendering, the wires 120 are compressed by calendering, and at least one of the n wires 120 is compressed into a non-circular shape.

[0039] like Figure 1 As shown, when n is an even number (n = 4, 6, 8, 10), due to the rolling process, the cross-sections of two of the n wires 120 can be circular, and the cross-sections of the n-2 wires can be non-circular. For example... Figure 2 As shown, when n is an even number (n = 3, 5, 7, 9, 11), due to the rolling process, the cross-section of one of the n wires 120 can be circular, and the cross-section of the n-1 wires can be non-circular. Here, the non-circular cross-section can be a symmetrical or asymmetrical ellipse.

[0040] The steel wire ropes used to reinforce the tire belt layer of a vehicle have a uniform distance between them to prevent rope overlap, thereby reducing the rotational resistance of the tire. For this purpose, it is preferable that the ropes extend uniformly in a certain direction.

[0041] As described above, before the rolling process, the n wires 120 can be arranged in a virtual first circle 130, and the direction of rolling can be represented by various points outside the virtual first circle 130. However, when the rolling process is performed in the wrong direction, there is a risk of wire misalignment and the wires not extending uniformly in a certain direction.

[0042] In the steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention, when the rope 110 formed by periodically twisting n wires 120 is rolled, since the direction of the rolling process is set to a specified direction, the rope 110 can be manufactured to extend uniformly in a certain direction.

[0043] Specifically, according to an embodiment of the present invention, when n is an even number (n = 4, 6, 8, 10), the rolling processing direction is determined such that the cross-sections of two of the n wires 120 remain circular, while the other wires have non-circular cross-sections. When n is an odd number (n = 3, 5, 7, 9, 11), the rolling processing direction is determined such that the cross-section of one of the n wires 120 remains circular, while the other wires have non-circular cross-sections.

[0044] When the calendering direction is determined by the above method, ropes that extend uniformly in a certain direction can be manufactured, thus preventing rope overlap and making the distance between ropes uniform.

[0045] According to an embodiment of the present invention, the rolling strength during rolling can be adjusted by the ratio of the diameter of the wire having a circular cross-section to the minor axis of the wire having a non-circular cross-section. When the wire whose cross-section is circular by rolling is referred to as the first wire 121, and the wire whose cross-section is non-circular by rolling is referred to as the second wire 122, the value of the minor axis d2 of the second wire 122 relative to the diameter d1 of the first wire 121 is preferably 0.70 to 0.98 (0.70 ≤ d2 / d1 ≤ 0.98).

[0046] Here, the minor axis d2 of the second line 122 can be Figure 1 and Figure 2 The length shown. However, when a non-circular cross-section is not formed as shown... Figure 3 When the ellipse is shown, the minor axis d2 of the second line 122 can be defined as the shortest distance from one side to the other from the center of the circle passing through the major axis d3, whose diameter is a non-circular cross section.

[0047] When the value of the minor axis d2 of the second thread 122 relative to the diameter d1 of the first thread 121 is too small (when the d2 / d1 value is less than 0.70), thread breakage may occur due to excessive calendering strength. In addition, when the second thread 122 is over-compressed, the rubber permeability may decrease due to insufficient space for rubber to permeate, which may actually reduce fatigue properties.

[0048] Conversely, when the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is too large (when the d2 / d1 value is greater than 0.98), the effect of calendering may not be expected, and the gap between the lines widens, thus increasing the possibility of moisture penetration, leading to concerns that durability and fatigue properties may be reduced.

[0049] Figure 4 The photograph illustrates, according to an embodiment of the present invention, that when n is an even number and its value is 6, the cross-sections of two lines are circular, and the cross-sections of four lines are non-circular. In the following, the effects of the present invention on initial adhesion and fatigue cycles are explained by comparing embodiments of the present invention with comparative examples.

[0050] Figures 5 to 10 The initial adhesion and fatigue cycles of embodiments of the present invention are compared with those of comparative examples based on the ratio of the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121.

[0051] Figure 5 Comparative Examples 1, 2, and 3 are shown where, when n is odd, the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 exceeds the range of 0.70 to 0.98, and Examples 1, 2, and 3 are shown where, when n is odd, the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is within the range of 0.70 to 0.98.

[0052] Figure 6 To show that Figure 5 A graph comparing the initial adhesion of Comparative Examples 1, 2, and 3 with that of Examples 1, 2, and 3. Figure 7 To show that Figure 5 A graph comparing the fatigue cycles of Comparative Examples 1, 2, and 3 with those of Examples 1, 2, and 3.

[0053] Figure 8 Comparative Examples 1, 2, and 3 are shown where, when n is an even number, the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 exceeds the range of 0.70 to 0.98, and Examples 1, 2, and 3 are shown where, when n is an even number, the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is within the range of 0.70 to 0.98.

[0054] Figure 9 To show that Figure 8 A graph comparing the initial adhesion of Comparative Examples 1, 2, and 3 with that of Examples 1, 2, and 3. Figure 10 To show that Figure 8 A graph comparing the fatigue cycles of Comparative Examples 1, 2, and 3 with those of Examples 1, 2, and 3.

[0055] exist Figures 5 to 10 In Comparative Example 2, since the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is less than 0.70, there is a problem that the initial adhesion and fatigue properties are actually reduced. This shows that when the second line 122 is over-compressed, the rubber permeability may decrease due to insufficient space for rubber permeability, which may actually reduce the fatigue properties.

[0056] In addition, Figures 5 to 10 In Comparative Example 2, when the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is less than 0.70, there is a problem that the line may break during the manufacturing process.

[0057] exist Figures 5 to 10 In comparative examples 1 and 3, since the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is greater than 0.98, it can be concluded that the initial adhesion and fatigue characteristics are reduced, and the stiffness coefficient of the major axis d3 has not increased.

[0058] When the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is greater than 0.98, the rolling effect cannot be expected, and when the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is greater than 0.98, the rigidity in the rotational direction cannot be improved, and therefore the durability cannot be improved.

[0059] Furthermore, when the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is greater than 0.98, it can be known that the possibility of moisture penetration increases due to the widening gap between the lines, leading to deterioration of durability and fatigue characteristics. Moreover, when the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is greater than 0.98, it is difficult to expect the effect of reducing the thickness of the rubber when embedding the wire rope into the rubber sheet.

[0060] Reference Figures 5 to 10According to an embodiment of the present invention, it can be seen that when the rolling process is performed such that the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is 0.70 to 0.98, the initial adhesion is improved, the fatigue characteristics are improved, and the stiffness coefficient of the major axis d3 is also increased compared to Comparative Examples 1, 2 and 3.

[0061] According to an embodiment of the present invention, when calendering is performed such that the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is 0.70 to 0.98, the permeability of the rubber becomes excellent, thereby preventing the durability of the wire rope from deteriorating due to the penetration of moisture or salt, and simultaneously improving the initial adhesion of the wire rope.

[0062] Furthermore, according to an embodiment of the present invention, when calendering is performed such that the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is 0.70 to 0.98, the durability and fatigue characteristics of the wire rope can be improved because the rigidity of the tire in the rotational direction is increased (the stiffness coefficient of the major axis d3 increases), and when the wire rope is embedded in the rubber sheet, the thickness of the rubber can be reduced without reducing the strength compared to a circular wire rope.

[0063] Therefore, according to an embodiment of the present invention, the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is preferably 0.70 to 0.98.

[0064] According to an embodiment of the present invention, calendering can be performed such that the tensile strength of the wire 120 changes before and after calendering. When the diameter of the wire 120 before calendering is referred to as d (mm), the first strength (Normal Tensile, NT) can be defined as 3,200-2,000×d (mm) ± 200 (MPa), the second strength (High Tensile, HT) can be defined as 3,500-2,000×d (mm) ± 200 (MPa), the third strength (Super Tensile, ST) can be defined as 3,850-2,000×d (mm) ± 200 (MPa), the fourth strength (Ultra Tensile, UT) can be defined as 4,200-2,000×d (mm) ± 200 (MPa), and the fifth strength (Mega Tensile, MT) can be defined as 4,600-2,000×d (mm) ± 200 (MPa). Here, the diameter d of the line 120 is the diameter of the line before the rolling process, which can be the same as the diameter d1 of the first line 121.

[0065] The tensile strength of the wire 120 before rolling can be any one of the first strength (NT), the second strength (HT), the third strength (ST), the fourth strength (UT), and the fifth strength (MT). The tensile strength of the wire 120 before rolling can be changed according to the required tensile strength in the wire rope.

[0066] According to an embodiment of the present invention, calendering can be performed to change the tensile strength of the wire 120. Specifically, calendering can be performed to reduce the tensile strength of the wire 120, and the wire 120, which had a tensile strength of the nth strength before calendering, can be calendered to have a tensile strength of the (n-1)th strength. (Here, n can be a value of 2, 3, 4, or 5.)

[0067] Specifically, when the tensile strength of the wire 120 is the fifth strength (MT) before the calendering process, the tensile strength of the wire 120 becomes the fourth strength (UT) after the calendering process, and when the tensile strength of the wire 120 is the fourth strength (UT) before the calendering process, the tensile strength of the wire 120 becomes the third strength (ST) after the calendering process.

[0068] As described above, the rolling process according to embodiments of the present invention can be performed to change the tensile strength of the wire 120. During rolling, the wire's physical properties can change due to compression. When rolling is performed without considering this factor, the tensile strength of the final manufactured wire rope cannot be accurately determined.

[0069] In order to solve the problems described above, the steel wire rope for reinforcing the tire belt layer according to embodiments of the present invention changes the physical property value (tensile strength) that is affected by the rolling process within a specified range.

[0070] According to an embodiment of the present invention, the wire rope for reinforcing the tire belt layer is rolled so that the wire 120, which had a tensile strength of the nth strength before the rolling process, has a tensile strength of the (n-1)th strength after the rolling process. Since the rolling process is performed to change the tensile strength within a set value, the tensile strength of the finally manufactured wire rope can be accurately known.

[0071] At this time, since the degree of change in the tensile strength of the wire 120 can vary depending on the diameter of the wire 120, the first strength (NT), the second strength (HT), the third strength (ST), the fourth strength (UT), and the fifth strength (MT) can be determined based on the diameter d of the wire 120.

[0072] Here, the wire 120 whose tensile strength is altered by calendering can be the second wire 122, which is compressed during calendering. However, the invention is not limited thereto; if necessary, the wire 120 whose tensile strength is altered by calendering can be both the first wire 121 and the second wire 122.

[0073] The diameter of the first wire 121 of the steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention can be from 0.1 mm to 0.6 mm, but is not limited thereto, and can be changed as needed.

[0074] The steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention is manufactured by rolling, and therefore can have excellent straightness.

[0075] Generally, steel wire ropes used as tire reinforcement materials require several months to be usable in tires. In other words, they are used several months after being wound onto a spool with a certain inner diameter. As mentioned above, due to the characteristic of steel wire ropes being used several months after winding, the straightness of the steel wire rope becomes an important characteristic for steel wire ropes used as tire reinforcement materials.

[0076] Poor straightness can affect the fairness of tire manufacturing operations and cause buckling and tip rising, which can lead to problems during calendering and cutting processes.

[0077] Excellent straightness quality refers to the quality of a straight line formed by the first axis that forms a vertical line from said point and the other end of the wire rope when the wire rope is wound on a spool for two months to one year, with one end of the wire rope fixed to a point and the wire rope lowered vertically by 400 mm. The smaller the gap between the first axis that forms a vertical line from said point and the other end of the wire rope, the better the straightness quality.

[0078] The steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention is manufactured by rolling, and therefore can have excellent straightness.

[0079] Specifically, when the wire rope manufactured according to the embodiments of the present invention is wound on a spool for two months to one year, one end of the wire rope is fixed to a point, and the wire rope is vertically lowered by 400mm, the interval formed by the first axis forming a vertical line from the point and the other end of the wire rope can be 40mm or less.

[0080] Figure 11 The diagram illustrates a comparison of the straightness quality of embodiments of the invention with comparative examples based on the ratio of the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121. Figure 11The diagram illustrates the interval formed by a first axis forming a vertical line from that point and the other end of the wire rope when the wire rope is wound on a spool for two months to one year, with one end of the wire rope fixed to a point and the wire rope lowered vertically by 400 mm.

[0081] Figure 11 Comparative Examples 1 and 2 show that the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 exceeds the range of 0.70 to 0.98, and Examples 1 and 2 show the straightness of Embodiments 1 and 2 where the value of the minor axis d2 of the second line 122 relative to the diameter d1 of the first line 121 is in the range of 0.70 to 0.98.

[0082] Reference Figure 11 According to embodiments of the present invention, it can be seen that when steel wire rope is manufactured by rolling, as the residual stress of the steel wire rope is eliminated, it can also have excellent straightness over time.

[0083] The steel wire rope for reinforcing the tire belt layer according to the above-described embodiment of the present invention has the following effects.

[0084] The steel wire rope for reinforcing the tire belt layer according to an embodiment of the present invention has the advantage of improving the durability and fatigue characteristics of the steel wire rope because the steel wire rope is manufactured by rolling.

[0085] Furthermore, the steel wire rope for reinforcing the tire belt layer according to embodiments of the present invention has the advantage of preventing the durability of the steel wire rope from deteriorating due to the penetration of moisture or salt by making the rubber permeability excellent. The steel wire rope for reinforcing the tire belt layer according to embodiments of the present invention also has the advantage of improving the initial adhesion and fatigue characteristics of the steel wire rope by making the rubber permeability excellent.

[0086] Furthermore, the steel wire rope for reinforcing the tire belt layer according to the embodiments of the present invention has the advantage of reducing the thickness of the rubber when the steel wire rope is embedded in the rubber sheet because it is manufactured by calendering. The steel wire rope for reinforcing the tire belt layer according to the embodiments of the present invention also has the advantage of improving its straightness through calendering.

[0087] In particular, when the tensile strength of the steel wire rope used to reinforce the tire belt layer according to the embodiment of the present invention after calendering is referred to as the nth strength, the tensile strength before calendering is the (n+1)th strength. Thus, compared with a steel wire rope having a circular shape, it has the advantage that the thickness of the rubber can be reduced without reducing its strength when the steel wire rope is embedded in the rubber sheet.

[0088] Furthermore, since the steel wire rope for reinforcing the tire belt layer according to the embodiments of the present invention is calendered while the value of the minor axis d2 of the second line relative to the diameter d1 of the first line is in the range of 0.70 to 0.98, it has the advantage of being able to manufacture the steel wire rope while preventing the durability and fatigue characteristics of the steel wire rope from deteriorating due to the penetration of moisture or salt, which would otherwise result in the occurrence of short lines or a decrease in rubber penetration.

[0089] As described above, the invention has been illustrated with reference to the embodiments shown in the accompanying drawings; however, this is merely illustrative, and those skilled in the art will understand that various modifications and variations of the embodiments can be made. Therefore, the true scope of protection of this invention should be determined by the technical spirit of the appended claims.

Claims

1. A steel wire cord for reinforcing a tire belt of a vehicle, characterized in that, comprises a rope formed by n number of lines being periodically twisted, the n number of lines are compressed by calendering, the lines are compressed by calendering and at least one of the n number of lines is compressed into a non-circular shape, wherein, when n is an odd number, the cross section of one of the n number of lines is circular and the cross section of n-1 number of lines is non-circular due to the calendering, when n is an even number, the cross section of two of the n number of lines is circular and the cross section of n-2 number of lines is non-circular due to the calendering, when the line whose cross section is circular due to the calendering is referred to as a first line and the line whose cross section is non-circular due to the calendering is referred to as a second line, the value of the minor axis of the second line with respect to the diameter of the first line is 0.70 to 0.98, when the diameter of the line before the calendering is performed is referred to as d (mm), a first strength is defined as 3,200-2,000 x d (mm) ± 200 (MPa), a second strength is defined as 3,500-2,000 x d (mm) ± 200 (MPa), a third strength is defined as 3,850-2,000 x d (mm) ± 200 (MPa), a fourth strength is defined as 4,200-2,000 x d (mm) ± 200 (MPa), a fifth strength is defined as 4,600-2,000 x d (mm) ± 200 (MPa), wherein, the tensile strength of the line before the calendering is performed has any one of the second strength, the third strength, the fourth strength and the fifth strength, the line having the tensile strength of the n-th strength before the calendering is processed into a line having a tensile strength of the n-1-th strength by the calendering.

2. The steel wire rope according to claim 1, characterized in that the number of the lines is 3 to 9.

3. The steel wire rope of claim 1, wherein, the diameter of the first line is 0.1 mm to 0.6 mm.

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