Steel cord for high-rubber-permeability engineering tire

Abstract

The invention discloses a steel cord for a rubber high-permeability engineering tire in the technical field of steel cord manufacturing, and the steel cord comprises a core strand, at least six outer-layer strands and outer wrapping wires, the outer-layer strands are uniformly woven and twisted on the periphery of the core strand in the circumferential direction, the outer wrapping wires are wound on the periphery of the outer-layer strands, and the outer wrapping wires are uniformly woven and twisted on the periphery of the outer-layer strands in the circumferential direction. The core strand comprises a first core strand monofilament and at least six second core strand monofilaments which are twisted around the first core strand monofilament, the outer-layer strand comprises a first outer-layer strand monofilament and at least five second outer-layer strand monofilaments which are twisted around the first outer-layer strand monofilament, and no gap exists between the outer-layer strand and the outer-layer strand. And gaps exist between the second outer-layer strand monofilaments. According to the steel cord, the gaps between the outer-layer stranded wire monofilaments are increased through the structural design, the performance of well improving the rubber permeability is achieved, meanwhile, under the condition that the number of the outer-layer stranded wire monofilaments is reduced, the breaking force of the steel cord is kept, and a tire has higher bearing capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of steel cord manufacturing, and in particular relates to a steel cord for rubber high-permeability engineering tires. Background Art

[0002] OTR radial tires operate in harsh environments, requiring high load-bearing capacity and fatigue resistance. Large-scale construction and mining operations can easily accelerate the wear of steel cords, even causing them to delaminate from the rubber. Therefore, steel cords must exhibit higher load-bearing capacity, fatigue resistance, and adhesion penetration.

[0003] Traditional OTR tires often use steel cord with the same core and outer strands, with identical filament diameters. This creates point contact between the core and outer strands, and the steel filaments are closely packed, resulting in small gaps between the filaments. This makes it difficult for rubber to penetrate, resulting in insufficient adhesion between the steel cord and rubber, and can easily lead to delamination. Summary of the Invention

[0004] The purpose of the present invention is to provide a steel cord for engineering tires with high rubber permeability. The gaps between the monofilaments of the outer layer strands are increased through structural design, thereby improving the bonding and penetration performance. At the same time, while reducing the number of steel wires in the outer layer strands, the breaking force of the steel cord is maintained, the bearing capacity remains unchanged, and the comprehensive performance of engineering machinery radial tires is improved.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A steel cord for a rubber high-permeability engineering tire comprises a core strand, an outer layer strand and an outer wrapping wire, wherein the outer layer strand is provided with at least six strands, which are uniformly twisted around the outer periphery of the core strand in a circumferential direction, and the outer wrapping wire is wound around the outer periphery of the outer layer strand. The core strand comprises a first core strand monofilament and at least six second core strand monofilaments twisted around the first core strand monofilament, and the outer layer strand comprises a first outer layer strand monofilament and at least five second outer layer strand monofilaments twisted around the first outer layer strand monofilament, no gaps exist between the outer layer strands, and gaps exist between the second outer layer strands and the second outer layer strands.

[0006] Furthermore, the gap distance between the second outer layer monofilaments is 0.010 to 0.060 mm.

[0007] Furthermore, the diameter of the first core strand monofilament is greater than the diameter of the second core strand monofilament, and the diameter of the first outer layer strand monofilament is greater than the diameter of the second outer layer strand monofilament.

[0008] Furthermore, the diameter d1 of the first core strand monofilament and the diameter d2 of the second core strand monofilament satisfy d1-d2≥0.005mm; the diameter d3 of the first outer layer strand monofilament and the diameter d4 of the second outer layer strand monofilament satisfy d3-d4≥0.005mm.

[0009] Furthermore, the twist direction of the second core strand monofilament in the core strand yarn is the same as the twist direction of the second outer layer strand monofilament in the outer layer strand yarn, the twist direction of the outer layer strand yarn and the core strand yarn is opposite to the twist direction of the second core strand monofilament, and the twist direction of the outer winding yarn is the same as the twist direction of the second core strand monofilament.

[0010] Furthermore, the twist direction of the second core strand monofilament in the core strand yarn and the twist direction of the second outer layer strand monofilament in the outer layer strand yarn are both S twist, the twist direction of the outer layer strand yarn and the core strand yarn is Z twist, and the twist direction of the outer winding yarn is S twist.

[0011] Furthermore, the twist direction of the second core strand monofilament in the core strand yarn and the twist direction of the second outer layer strand monofilament in the outer layer strand yarn are both Z twist, the twist direction of the outer layer strand yarn and the core strand yarn is S twist, and the twist direction of the outer winding yarn is Z twist.

[0012] Furthermore, the twist pitch of the second core strand in the core strand is the same as the twist pitch of the second outer strand in the outer layer strand, and the twist pitch of the outer layer strand and the core strand is greater than the twist pitch of the second core strand.

[0013] Furthermore, the twist pitch of the second core strand monofilament in the core strand yarn and the twist pitch of the second outer layer strand monofilament in the outer layer strand yarn are 7.0 to 16.0 mm, the twist pitch of the outer layer strand yarn and the core strand yarn is 1.05 to 2.30 times the twist pitch of the second core strand monofilament, and the twist pitch of the outer winding yarn is 4.0 to 6.0 mm.

[0014] Furthermore, the diameters of the core strand monofilament and the outer layer strand monofilament are in the range of 0.200 to 0.400 mm, preferably 0.200 to 0.300 mm.

[0015] Furthermore, the diameter of the outer winding wire ranges from 0.150 to 0.250 mm, preferably from 0.150 to 0.200 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention changes the structure of the steel cord. The core strands are composed of a first core strand monofilament and at least six second core strand monofilaments, and the outer layer strands are composed of a first outer layer strand monofilament and at least five second outer layer strand monofilaments. The core strands and the outer layer strands adopt the same twist direction, and the outer layer strands and the core strands adopt different twist directions. The diameter of the first core strand monofilament of the core strands is greater than the diameter of the second core strand monofilament, and the diameter of the first outer layer strand monofilament of the outer layer strands is greater than the diameter of the second outer layer strand monofilament. The gaps between the outer layer strands are increased. When applied to tires, the steel cord has the performance of greatly improving the rubber permeability. At the same time, when the number of outer layer strands is reduced, the breaking force of the steel cord can still be maintained, so that the tire has a higher load-bearing capacity, the glue penetration performance, impact resistance and fatigue resistance of the steel cord are improved, and the comprehensive performance of engineering machinery radial tires is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the cross-sectional structure of a steel cord for a rubber high-permeability engineering tire according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of a steel cord for an engineering tire in the prior art.

[0018] In the figure, 1, core strand; 2, outer strand; 3, outer wrapping wire; 101, first core strand monofilament; 102, second core strand monofilament; 201, first outer strand monofilament; 202, second outer strand monofilament. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] Source of terms and definitions: GB / T 30830-2014 Steel cord for engineering radial tires Monofilament: A steel wire that is a separate element in a strand or cord; Outer wrap: a single filament wrapped around the steel cord in a spiral form; Strand: A structure formed by twisting a group of monofilaments together into one or more layers of spirals; Core: One or more monofilaments or strands that serve as the axis of twisting and around which other units can be wound.

[0021] like Figure 1 As shown, a steel cord for a rubber high-permeability engineering tire of the present invention comprises a core strand 1, an outer layer strand 2 and an outer wrapping 3.

[0022] The outer layer strands 2 are provided with at least six strands, which are evenly twisted around the outer periphery of the core strands 1 along the circumferential direction, and the outer winding wires 3 are wound around the outer periphery of the outer layer strands 2 .

[0023] There is no gap between the outer layer strands 2 .

[0024] The core strand yarn 1 includes a first core strand monofilament 101 and at least six second core strand monofilaments 102. The first core strand monofilament 101 is located in the middle of the second core strand monofilament 102. The second core strand monofilament 102 is evenly twisted around the outer periphery of the first core strand monofilament 101 along the circumferential direction to form a 1×d1+6×d2 structure, where d1 and d2 are the diameters of the first core strand monofilament 101 and the second core strand monofilament 102, respectively.

[0025] The diameter d1 of the first core monofilament 101 is greater than the diameter d2 of the second core monofilament 102 .

[0026] As a preferred embodiment, the diameter d1 of the first core monofilament 101 and the diameter d2 of the second core monofilament 102 satisfy d1-d2≥0.005 mm.

[0027] The outer layer strand 2 includes a first outer layer strand monofilament 201 and at least five second outer layer strand monofilaments 202. The first outer layer strand monofilament 201 is located in the middle of the second outer layer strand monofilament 202. The second outer layer strand monofilament 202 is evenly twisted around the first outer layer strand monofilament 201 along the circumferential direction to form a 1×d3+5×d4 structure, where d3 and d4 are the diameters of the first outer layer strand monofilament 201 and the second outer layer strand monofilament 202, respectively.

[0028] The diameter d3 of the first outer layer monofilament 201 is greater than the diameter d4 of the second outer layer monofilament 202 .

[0029] As a preferred embodiment, the diameter d3 of the first outer layer monofilament 201 and the diameter d4 of the second outer layer monofilament 202 satisfy d3-d4≥0.005 mm.

[0030] There are gaps between the second outer layer monofilaments 202 .

[0031] In a preferred embodiment, the gap distance dx between the second outer layer strand filaments 202 is 0.010 mm to 0.060 mm.

[0032] In a specific embodiment, the gap distance dx between the second outer layer monofilaments 202 is 0.043 mm.

[0033] The diameter of the monofilament suitable for the steel cord core strand 1 and the outer strand 2 is generally in the range of 0.200 to 0.400 mm, preferably 0.200 to 0.300 mm. Examples of the monofilament diameter are 0.220 mm, 0.230 mm, 0.250 mm, 0.280 mm, and 0.300 mm.

[0034] The diameter of the outer wrapping filament 3 suitable for the steel cord is generally in the range of 0.150 to 0.250 mm, preferably 0.150 to 0.200 mm. Examples of the diameter of the monofilament are 0.150 mm, 0.175 mm, and 0.200 mm.

[0035] The core strands 1 and the outer strands 1 are twisted in the same direction, and at least six outer strands 2 are twisted with one core strand 1 in different directions.

[0036] More specifically, the twist direction of the second core strand 102 in the core strand 1 is the same as the twist direction of the second outer layer strand 202 in the outer layer strand 2, the twist direction of at least six outer layer strands 2 twisted with the core strand 1 is opposite to the twist direction of the second core strand 102 in the core strand 1, and the twist direction of the outer winding wire 3 is the same as the twist direction of the second core strand 102 in the core strand.

[0037] In one embodiment, the twist direction of the second core strand 102 in the core strand 1 and the twist direction of the second outer layer strand 202 in the outer layer strand 2 are both S twist, the twist direction of the outer layer strand 2 and the core strand 1 is Z twist, and the twist direction of the outer winding wire 3 is S twist.

[0038] In another embodiment, the twist direction of the second core strand 102 in the core strand 1 and the twist direction of the second outer layer strand 202 in the outer layer strand 2 are both Z twist, the twist direction of the outer layer strand 2 and the core strand 1 is S twist, and the twist direction of the outer winding wire 3 is Z twist.

[0039] The core strands 1 and the outer strands 2 have the same lay length, and the lay length of the outer strands 1 and the core strands 1 is greater than the lay length of the core strands.

[0040] Specifically, the twist pitch of the second core strand 102 in the core strand 1 is the same as the twist pitch of the second outer strand 202 in the outer strand 2, and the twist pitch of the outer strand 1 and the core strand 1 is greater than the twist pitch of the second core strand 102 in the core strand 1.

[0041] In a preferred embodiment, the twist length of the second core strand 102 in the core strand 1 and the twist length of the second outer strand 202 in the outer strand 2 are 7.0 to 16.0 mm, the twist length of the outer strand 2 and the core strand 1 is 1.05 to 2.30 times the twist length of the second core strand 102 in the core strand 1, and the twist length of the outer winding wire 3 is 4.0 to 6.0 mm.

[0042] In a specific embodiment, the twist length of the second core strand 102 in the core strand 1 and the twist length of the second outer strand 202 in the outer strand 2 are both 12.6 mm, the twist length of the outer strand 2 and the core strand 1 is 20.1 mm, and the twist length of the outer winding wire 3 is 5.1 mm.

[0043] Example 1

[0044] The steel cord structure in this embodiment is 0.235+6×0.23+6×(0.235+5×0.23)+0.15ST steel cord. As shown in Table 1, the six outer layer strands 2 are evenly twisted around the outer periphery of the core strand 1 in the circumferential direction, and there is no gap between the outer layer strands 2. The core strand 1 is composed of one first core strand monofilament 101 and six second core strand monofilaments 102, and the outer layer strands 2 are composed of one first outer layer monofilament 201 and five second outer layer monofilaments 202. The diameter of the first core strand monofilament 101 is 0.235 mm, the diameter of the second core strand monofilament 102 is 0.23 mm, and the diameter of the first outer layer monofilament 201 is 0.235 mm. The diameter of strand 201 is 0.235 mm, the diameter of the second outer strand 202 is 0.23 mm, and the diameter of the outer wrapping 3 is 0.15 mm. Both the core strand 1 and the outer strand 2 are twisted in an S-twist pattern. The six outer strands 2 are twisted with the core strand 1 in a Z-twist pattern, while the outer wrapping 3 is twisted in an S-twist pattern. The lay lengths of the core strand 1 and the outer strand 2 are both 12.6 mm, the lay length of the outer strand 2 with the core strand 1 is 20.1 mm, and the lay length of the outer wrapping 3 is 5.1 mm. In the outer strand 2, the gap between the second outer strand 202 is 0.043 mm.

[0045] The existing technical engineering tire steel cord 7×7×0.22+0.15HT steel cord structure is as follows Figure 2 As shown in Table 1, the six outer strands are evenly twisted around the outer periphery of a core strand along the circumferential direction, and there are no gaps between the outer strands. Both the core strand and the outer strand are composed of a single filament in the inner layer and six single filaments in the outer layer. There are also no gaps between the six single filaments in the outer layer of the outer strand. The single filament diameters of the core strand and the outer strand are both 0.22mm, and the diameter of the outer winding wire is 0.15mm; the twist direction of the core strand and the outer strand are both S twist, the twist direction of the six outer strands twisted with the core strand is Z twist, and the twist direction of the outer winding wire is S twist; the twist length of the core strand and the outer strand are both 12.6mm, the twist length of the six outer strands twisted with the core strand is 20.6mm, and the twist length of the outer winding wire is 5.0mm.

[0046] The steel cord of this embodiment was compared with the existing 7×7×0.22+0.15HT steel cord. The test results are shown in Table 1.

[0047] Table 1

[0048] As can be seen from Table 1, compared with the existing 7×7×0.22+0.15HT steel cord, under the condition of equal cord strength: Steel cord penetration rate increased by 90%; The cord strength index increased by 3%; The cord weight index is saved by 5%.

[0049] The present invention increases the gap between the second layer of monofilaments of the outer layer strands through structural design, so that the steel cord has the performance of greatly improving the rubber permeability. At the same time, while reducing the number of monofilaments of the outer layer strands, the breaking force of the steel cord can be maintained, so that the tire has a higher load-bearing capacity and improves the comprehensive performance of the engineering machinery radial tire.

[0050] The present invention has been disclosed above with preferred embodiments, which are not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation solutions fall within the protection scope of the present invention.

Claims

1. A steel cord for rubber high permeability engineering tire, characterized in that: The invention comprises a core strand (1), an outer layer strand (2) and an outer wrapping wire (3), wherein the outer layer strand (2) is provided with at least six strands, which are uniformly twisted around the outer periphery of the core strand (1) in a circumferential direction, and the outer wrapping wire (3) is wound around the outer periphery of the outer layer strand (2). The core strand (1) comprises a first core strand monofilament (101) and at least six second core strand monofilaments (102) twisted around the first core strand monofilament (101), and the outer layer strand (2) comprises a first outer layer strand monofilament (201) and at least five second outer layer strand monofilaments (202) twisted around the first outer layer strand monofilament (201). There is no gap between the outer layer strands (2) and there is a gap between the second outer layer strand monofilaments (202) and the second outer layer strand monofilaments (202).

2. The steel cord for rubber high permeability engineering tire according to claim 1, characterized in that: The gap distance between the second outer layer monofilaments (202) and the second outer layer monofilaments (202) is 0.010 to 0.060 mm.

3. The steel cord for rubber high permeability engineering tire according to claim 1, characterized in that: The diameter of the first core strand monofilament (101) is greater than the diameter of the second core strand monofilament (102), and the diameter of the first outer layer strand monofilament (201) is greater than the diameter of the second outer layer strand monofilament (202).

4. The steel cord for rubber high permeability engineering tire according to claim 3, characterized in that: The diameter d1 of the first core strand monofilament (101) and the diameter d2 of the second core strand monofilament (102) satisfy d1-d2≥0.005mm; the diameter d3 of the first outer layer strand monofilament (201) and the diameter d4 of the second outer layer strand monofilament (202) satisfy d3-d4≥0.005mm.

5. The steel cord for rubber high permeability engineering tire according to claim 1, characterized in that: The twist direction of the second core strand (102) in the core strand (1) is the same as the twist direction of the second outer layer strand (202) in the outer layer strand (2); the twist direction of the outer layer strand (2) and the core strand (1) is opposite to the twist direction of the second core strand (102); and the twist direction of the outer wrapping yarn (3) is the same as the twist direction of the second core strand (102).

6. The steel cord for rubber high permeability engineering tire according to claim 5, characterized in that: The twist direction of the second core strand (102) in the core strand (1) and the twist direction of the second outer layer strand (202) in the outer layer strand (2) are both S twist, the twist direction of the outer layer strand (2) and the core strand (1) is Z twist, and the twist direction of the outer winding yarn (3) is S twist.

7. The steel cord for rubber high permeability engineering tire according to claim 5, characterized in that: The twist direction of the second core strand monofilament (102) in the core strand yarn (1) and the twist direction of the second outer layer strand monofilament (202) in the outer layer strand yarn (2) are both Z twist, the twist direction of the outer layer strand yarn (2) and the core strand yarn (1) is S twist, and the twist direction of the outer winding yarn (3) is Z twist.

8. The steel cord for rubber high permeability engineering tire according to claim 1, characterized in that: The twist pitch of the second core strand (102) in the core strand (1) is the same as the twist pitch of the second outer strand (202) in the outer strand (2), and the twist pitch of the outer strand (2) and the core strand (1) is greater than the twist pitch of the second core strand (102).

9. The steel cord for rubber high permeability engineering tire according to claim 7, characterized in that: The twist pitch of the second core strand (102) in the core strand (1) and the twist pitch of the second outer layer strand (202) in the outer layer strand (2) are 7.0 to 16.0 mm, the twist pitch of the outer layer strand (2) and the core strand (1) is 1.05 to 2.30 times the twist pitch of the second core strand (102), and the twist pitch of the outer winding yarn (3) is 4.0 to 6.0 mm.

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