Ultrahigh-ductility steel cord for engineering radial tire

Abstract

The invention discloses an ultrahigh ductility engineering radial tire steel cord, which comprises a plurality of spirally wound basic plied yarns, each basic plied yarn comprises a central monofilament and a plurality of outer monofilaments, the plurality of outer monofilaments are uniformly twisted on the periphery of the central monofilament along the circumferential direction, and the outer monofilaments are uniformly twisted on the periphery of the central monofilament along the circumferential direction. And gaps are formed between the plurality of basic strands and between the plurality of outer-layer monofilaments. The impact resistance, loading capacity and wear resistance of the tire can be improved, the service life of the tire is prolonged, and safe and efficient operation of engineering equipment is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel cords, and particularly relates to a steel cord with super-high ductility for engineering radial tires. BACKGROUND

[0002] The steel cord with super-high ductility for engineering radial tires is a high-performance framework material for engineering machinery tires, and is mainly applied to tires of various engineering machinery equipment, such as mine trucks in mine exploitation, loaders on construction sites, excavators and the like. These devices usually work in complex road conditions and heavy load environments, and have extremely high requirements for the performance of the tires, and higher requirements for the improvement of the ductility of the steel cord for engineering radial tires. SUMMARY

[0003] The application aims to overcome the deficiencies in the prior art, and provides a steel cord with super-high ductility for engineering radial tires, which improves the impact resistance, load capacity and wear resistance of the tire, prolongs the service life of the tire, and guarantees the safe and efficient operation of the engineering equipment.

[0004] To achieve the above technical purposes, the application adopts the following scheme: The application provides a steel cord with super-high ductility for engineering radial tires, which comprises a plurality of spiral-wound basic strands, each of the basic strands comprises a center monofilament and a plurality of outer monofilaments, the plurality of outer monofilaments are uniformly twisted on the outer periphery of the center monofilament in the circumferential direction, and gaps exist between the plurality of basic strands and between the plurality of outer monofilaments.

[0005] Further, the number of the basic strands is 4.

[0006] Further, the number of the outer monofilaments is 4, 5, 6, 7, 8 or 9.

[0007] Further, the basic strands are not located at the center position of the steel cord.

[0008] Further, the diameter of the center monofilament is greater than the diameter of the outer monofilament.

[0009] Further, the diameter da of the center monofilament and the diameter db of the outer monofilament satisfy db+0.001~0.030mm=da.

[0010] Further, the diameter of the center monofilament ranges from 0.15mm to 0.45mm, and the diameter of the outer monofilament ranges from 0.15mm to 0.45mm.

[0011] Further, the gap distance between the plurality of basic strands is 0.30mm to 0.60mm, and the gap distance between the plurality of outer monofilaments is 0.005mm to 0.015mm.

[0012] Further, the twist pitch of the single filament in the basic strand is 2.5-12 mm, and the twist pitch of the multiple basic strands is 10-30 mm.

[0013] Further, the helical winding of the basic strand and the twisting of the single filament in the basic strand are in the same direction S or Z. Advantages

[0014] The present application is composed of multiple helically wound basic strands, each of which includes a single center filament and multiple outer layer filaments, the multiple outer layer filaments are uniformly twisted around the periphery of the center filament in the circumferential direction, and there are gaps between the multiple basic strands and between the multiple outer layer filaments, when plastic deformation occurs under stress, the gaps between the multiple basic strands and between the multiple outer layer filaments become larger, thereby being able to withstand great tension without breaking, having high ductility, and the existence of the gaps makes the steel cord and the rubber have strong permeability, so that it can repeatedly withstand stress such as extrusion and tension, reduce the risk of breaking, and improve the durability and safety of the tire.

[0015] The present application can better adapt to the continuous expansion and contraction of the tire during rolling and turning, reduce fatigue damage, and in combination with its high strength characteristics, can significantly prolong the wear period and overall service life of the tire, and reduce the frequency and cost of tire replacement of engineering vehicles.

[0016] As the "skeleton" of the radial tire, the ductility of the steel cord can relieve the connection stress of the tire body and the bead, the tread and other components, reduce the delamination and cracking problems caused by the difference in material deformation, and enhance the integrity of the overall structure of the tire, especially suitable for heavy load and high load requirements of giant engineering tires (such as loader and dump truck tires).

[0017] The present application enables the steel cord to absorb more energy through its own deformation when the tire is subjected to severe impact (such as the instantaneous stress of the engineering vehicle under bumpy and heavy load on rough road), reduces the risk of local stress concentration and the rupture of the steel cord or the collapse of the tire body, and is especially suitable for heavy load and harsh working conditions in mines and infrastructure. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structure schematic diagram of a super-high-ductility steel cord for engineering radial tires, i.e., 4x(0.315+6x0.30) SHE steel cord, provided by an embodiment of the present application; Figure 2 is a structure schematic diagram of a high-ductility steel cord for engineering radial tires, i.e., a traditional 4x6x0.25 HE steel cord, provided by an embodiment of the present application; Figure 3 is a load-strain curve diagram of the 4x(0.315+6x0.30) SHE steel cord and the traditional 4x6x0.25 HE steel cord, provided by an embodiment of the present application. DETAILED DESCRIPTION

[0019] The application will be further described below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application. Example 1

[0020] The present embodiment provides a kind of super high ductility engineering radial tire steel cord, it is 4 × (1+M) structure: by 4 basic strands I group, each basic strand I is by 1+M structure double-layer silk rope, double-layer silk rope includes center monofilament a and outer layer monofilament b, the number of center monofilament a is 1, the number of outer layer monofilament b is M=4, 5, 6, 7, 8 or 9, center monofilament a is located in the middle of outer layer monofilament b, outer layer monofilament b is uniformly twisted in the periphery of center monofilament a along the circumferential direction, forms basic strand I, 4 basic strands I are assembled by twisting, and super high ductility engineering tire steel cord is formed by spirally winding 4 basic strands I, and it does not have one or more basic strands I in the center position of steel cord.

[0021] The diameter da of the center monofilament is greater than the diameter db of the outer layer monofilament. The diameter da of the center monofilament and the diameter db of the outer layer monofilament satisfy db+0.001~0.030mm=da, preferably db+0.015mm=da. The diameter da of the center monofilament ranges from 0.15 to 0.45 mm, preferably from 0.25 to 0.35 mm. The diameter db of the outer layer monofilament ranges from 0.15 to 0.45 mm, preferably from 0.25 to 0.35 mm.

[0022] The gap distance between the plurality of basic strands I is 0.30~0.60mm, and there is also a gap between the plurality of outer layer monofilaments b, and the gap distance is 0.005~0.015mm.

[0023] The twisting pitch of the monofilament in the basic strand I is 2.5~12mm, preferably 6~9mm, and the twisting pitch of the plurality of basic strands I is 10~30mm, preferably 12.5~18.5mm. The 4 basic strands I are twisted according to the set twisting pitch and the same twisting direction. During the twisting process, the twisting point only has a limiting effect, and there is no fixed position tight winding and twisting effect. The inner layer of the basic strand I 1+M and the outer layer of the plurality of basic strands I are spirally wound together to form two same-twisting-direction shaft layers. The spiral winding of the basic strand I and the twisting of the monofilament in the basic strand are in the same direction S or Z.

[0024] The super high ductility engineering radial tire steel cord with the 4 × (1+M) structure has the characteristics of super high ductility. The rubber in the steel cord reinforced tire belt is filled with the steel cord, and the rubber penetrates into the space between the strands and the filaments as much as possible to avoid insufficient penetration of the rubber, which leads to poor mechanical properties of the steel cord and the strands in the tire, causes corrosion and accelerates the fatigue process. Example 2

[0025] The present embodiment provides a super-high ductility steel cord for engineering radial tire, which is a 4x(1+M) structure: composed of 4 basic strands I, each basic strand I is composed of a double-layer wire rope of 1+M structure, the double-layer wire rope includes a center filament a and an outer layer filament b, the number of the center filament a is 1, the number of the outer layer filament b is M=4, the center filament a is located in the middle of the outer layer filament b, the outer layer filament b is uniformly twisted on the periphery of the center filament a in the circumferential direction to form the basic strand I, 4 basic strands I are assembled by twisting, and the super-high ductility steel cord for engineering tire is formed by spirally winding the 4 basic strands I, and neither one nor more basic strands I are located at the center position of the steel cord.

[0026] The diameter da of the center filament is greater than the diameter db of the outer layer filament. The diameter da of the center filament and the diameter db of the outer layer filament satisfy db+0.001~0.030mm=da, preferably db+0.015mm=da. In the present embodiment, the diameter da of the center filament is 0.275mm. The diameter db of the outer layer filament is 0.26mm.

[0027] The gap distance between the multiple basic strands I is 0.30mm, and there is also a gap between the multiple outer layer filaments b, and the gap distance is 0.005mm.

[0028] The twisting pitch of the filaments in the basic strand I is 6mm, and the twisting pitch of the multiple basic strands I is 12.5mm. The 4 basic strands I are twisted at the set twisting pitch and the same twist direction, and the twisting point only has a limiting effect during the twisting process, and there is no fixed position tight winding twisting effect. The inner layer of the basic strand I 1+M and the outer layer of the multiple basic strands I are spirally wound together to form two same-twist-direction axial layers, and the spiral winding of the basic strand I and the twisting of the filaments in the basic strand are in the same direction S or Z.

[0029] The super-high ductility steel cord for engineering radial tire with the 4x(1+M) structure has the characteristics of super-high ductility, the rubber in the steel cord reinforced tire belt is filled, and the rubber penetrates into the space between the strands and the filaments as much as possible, avoiding insufficient rubber penetration, leading to poor mechanical properties of the steel cord and the strands in the tire, causing corrosion and accelerating the fatigue process. Example 3

[0030] The embodiment provides a kind of super high ductility engineering radial tire steel cord, it is 4 × (1+M) structure: by 4 basic strands I group, each basic strand I is by the double-layer silk rope of 1+M structure, double-layer silk rope includes center monofilament a and outer layer monofilament b, the number of center monofilament a is 1, the number of outer layer monofilament b is M=9, center monofilament a is located in the middle of outer layer monofilament b, outer layer monofilament b is uniformly twisted on the periphery of center monofilament a along the circumferential direction, forms basic strand I, 4 basic strands I are assembled by twisting, and super high ductility engineering tire steel cord is formed by spirally winding 4 basic strands I, and it does not have one or more basic strands I in the center position of steel cord.

[0031] The diameter da of the center monofilament is greater than the diameter db of the outer layer monofilament. The diameter da of the center monofilament and the diameter db of the outer layer monofilament satisfy db+0.001~0.030mm=da, preferably satisfy db+0.015mm=da. The diameter da of the center monofilament is 0.295mm. The diameter db of the outer layer monofilament is 0.28mm.

[0032] The gap distance between the plurality of basic strands I is 0.60mm, and there is also a gap between the outer layer monofilament b and the center monofilament a in the basic strand I, and the gap distance is 0.015mm.

[0033] The monofilament winding pitch in the basic strand I is 9mm, and the winding pitch of the plurality of basic strands I is 18.5mm. The 4 basic strands I are twisted according to the set pitch and the same twist direction, and the twisting point is only a limiting action during the twisting process, and there is no fixed position tight hoop twisting action. The inner layer of the basic strand I 1+M and the outer layer of the plurality of basic strands I are spirally wound together to form two same-twist-direction shaft layers. The spiral winding of the basic strand I and the monofilament twisting in the basic strand are wound in the same direction S or Z.

[0034] The super high ductility engineering radial tire steel cord with the 4 × (1+M) structure has the characteristics of super high ductility. The rubber in the steel cord reinforced tire belt is filled with the rubber, and the rubber penetrates into the space between the strands and the filaments as much as possible. Avoid insufficient rubber penetration, which leads to poor mechanical properties of the steel cord and the strands in the tire, causing corrosion and accelerating the fatigue process. Embodiment 4

[0035] As Figure 1As shown, the present embodiment provides a super high extendability steel cord for engineering radial tire, which is a 4x(1+M) structure: composed of 4 basic strands I, each basic strand I is composed of a double-layer wire rope of 1+M structure, the double-layer wire rope includes a center filament a and an outer layer of filaments b, the number of center filaments a is 1, the number of outer layer filaments b is 6, the center filament a is located in the middle of the outer layer filaments b, the outer layer filaments b are uniformly twisted on the periphery of the center filament a in the circumferential direction to form the basic strand I, 4 basic strands I are assembled by twisting, and the super high extendability steel cord for engineering tire is formed by spirally winding the 4 basic strands I, and there is no one or more basic strands I located at the center position of the steel cord.

[0036] The diameter da of the center filament is greater than the diameter db of the outer layer filament. The diameter da of the center filament and the diameter db of the outer layer filament satisfy db+0.001~0.030mm=da, preferably db+0.015mm=da. In the present embodiment, the diameter da of the center filament is 0.315mm. The diameter db of the outer layer filament is 0.30mm.

[0037] The gap distance between the plurality of basic strands I is 0.42mm, and there is also a gap between the plurality of outer layer filaments b, and the gap distance is 0.01mm.

[0038] The twisting pitch of the filaments in the basic strand I is 7.5mm, and the twisting pitch of the plurality of basic strands I is 15.5mm. The 4 basic strands I are twisted at the set twisting pitch and the same twisting direction, and the twisting point only has a limiting effect in the twisting process, and there is no fixed position tight winding twisting effect. The inner layer of the basic strand I 1+M and the outer layer of the plurality of basic strands I are spirally wound together to form two same-twisting-direction axial layers, and the spiral winding of the basic strand I and the twisting of the filaments in the basic strand are in the same direction S or Z.

[0039] The super high extendability steel cord for engineering radial tire with the 4x(1+M) structure has the characteristics of super high extendability, the rubber in the steel cord reinforced tire belt is filled with the steel cord, and the rubber penetrates into the space between the strands and the filaments as much as possible, avoiding insufficient penetration of the rubber, which leads to poor mechanical properties of the steel cord and the strands in the tire, causing corrosion and accelerating the fatigue process.

[0040] As shown in Figure 1 , Figure 2 and Figure 3 , the 4x(0.315+6x0.30)SHE (Super High Extendability) steel cord has the following advantages compared with the traditional 4x6x0.25HE (High Extendability) steel cord (see Table 1 below): Table 1. Comparison of 4×(0.315+6×0.30)SHE steel cord and traditional 4×6×0.25HE steel cord Steel cord structure 4×(0.315+6×0.30)SHE 4×6×0.25HE Diameter (mm) 2.80 1.76 Linear density (g / m) 17.50 11.17 Twist length (mm) 7.5 / 15.5 5.7 / 9.5 twist direction S / S S / S Breaking force(N) 5000 2485 Breaking force elongation (%) ≥8.0 ≥4.0 Elongation at break increased by % 100% / Rubber filling ratio per unit volume of steel cord (%) 70.2 55.3 The rubber filling ratio per unit volume of steel cord is increased by % 26.94% / The stretching principle of ultra-high ductility steel cord is based on the plastic deformation and organizational structure control of the material. The core is to achieve ultra-high ductility through the mechanical action and microstructural changes during the stretching process ( Figure 3 The ultra-high ductility of the steel cord allows the rubber to be completely filled into and around the steel cord, preventing the intrusion of air, moisture, and other harmful substances, and preventing the steel cord from rusting and corroding.

[0041] Compared with traditional high-ductility steel cord, ultra-high ductility steel cord has a higher rubber filling ratio per unit volume of steel cord, as follows: The density of iron is 7.86 g / cm3, and the density of rubber in tires is 1.1 g / cm3; the linear density of SHE steel cord is 17.50 g / m, and the linear density of HE steel cord is 11.17 g / m.

[0042] Volume of 1 meter steel cord: V SHE =6.16 cubic centimeters V HE =2.60 cubic centimeters 1 meter steel cord volume steel cord weight (theoretical full filling): W SHE =6.16×7.86=48.4176 grams W HE =2.60×2.60=20.436 grams Weight of 1 meter steel cord volume rubber: W SHE =(48.4176-17.50) / 7.86×1.1=4.33 grams W HE =(20.436-10.17) / 7.86×1.1=1.44 grams Rubber filling ratio within 1 meter steel cord volume (%): SHE=4.33 / 6.16=70.2% HE=1.44 / 2.60=55.3%.

[0043] In summary, the present invention uses the characteristics of ultra-high ductility engineering tire steel cord to allow rubber to fully penetrate into the spaces between the strands and between the silk threads, avoiding insufficient rubber penetration, which leads to deterioration of the mechanical properties of the steel cord and strands in the tire, causing corrosion and accelerating the fatigue process, eliminating the air content between the strands of the tire steel cord, and improving the service life of the tire. Ultra-high ductility engineering radial tire steel cord is a key upgrade of tire skeleton materials. Its beneficial effects are mainly reflected in improving tire performance, adapting to complex working conditions, and extending service life. Through the combination of "strong toughness + deformation adaptability", it provides core performance support for engineering tires from the aspects of safety, durability, and economy, especially in line with the rigid requirements of engineering vehicles for tires with "heavy load, durable, and long life", as follows: 1. Extend tire life. Traditional steel cords, when insufficiently ductile, are prone to fatigue fracture due to repeated deformation, leading to premature tire damage. Ultra-high-ductility steel cords can better adapt to the tire's continuous expansion and contraction during rolling and steering, reducing fatigue damage. Combined with their high strength, they can significantly extend tire wear cycles and overall service life, reducing the frequency and cost of tire replacements for construction vehicles.

[0044] 2. Optimize tire structural durability. As the "skeleton" of radial tires, the ductility of steel cord can alleviate the stress in the connection between the carcass, bead, tread, and other components, reducing delamination and cracking caused by material deformation differences, and enhancing the integrity of the tire's overall structure. This is particularly suitable for the heavy-duty and high-load requirements of giant engineering tires (such as loader and dump truck tires).

[0045] 3. Enhanced tire impact and fatigue resistance. Ultra-high ductility enables the steel cord to absorb more energy through deformation when the tire is subjected to severe impact (such as the instantaneous stress of construction vehicles on rough roads or under heavy loads). This reduces local stress concentration and the risk of steel cord breakage or tire carcass collapse. This makes it particularly suitable for heavy-load, harsh working conditions such as mining and infrastructure construction.

[0046] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A steel cord for an ultra-high ductility engineering radial tire, characterized in that: It comprises a plurality of spirally wound basic strands, each of which comprises a central monofilament and a plurality of outer monofilaments, the plurality of outer monofilaments being evenly twisted around the central monofilament in a circumferential direction, and gaps existing between the plurality of basic strands and the plurality of outer monofilaments.

2. The ultra-high ductility engineering radial tire steel cord according to claim 1, characterized in that: The number of basic strands is 4.

3. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The number of outer monofilaments is 4, 5, 6, 7, 8 or 9.

4. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The basic strand is not located in the center of the steel cord.

5. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The diameter of the central monofilament is larger than the diameter of the outer monofilament.

6. The ultra-high ductility steel cord for engineering radial tire according to claim 5, characterized in that: The diameter da of the center monofilament and the diameter db of the outer monofilament satisfy db+0.001~0.030mm=da.

7. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The diameter of the central monofilament ranges from 0.15 to 0.45 mm, and the diameter of the outer monofilament ranges from 0.15 to 0.45 mm.

8. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The gap distance between the multiple basic strands is 0.30-0.60 mm, and the gap distance between the multiple outer monofilaments is 0.005-0.015 mm.

9. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The twist pitch of the monofilament in the basic strand is 2.5 to 12 mm, and the twist pitch of the multiple basic strands is 10 to 30 mm.

10. The ultra-high ductility steel cord for engineering radial tire according to claim 1, characterized in that: The helical winding of the basic strands is done in the same direction (S or Z) as the twisting of the monofilaments in the basic strands.

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