A highly flexible drag chain cable

Abstract

The present invention relates to a highly flexible drag chain cable, the structure of which from inside to outside comprises: an insulating wire core, an inner sheath (6), a shielding layer (7), and an outer sheath (8); the insulating wire core comprises a conductor layer and an insulating layer (4) from inside to outside, the insulating wire core is at least two, and a plurality of the insulating wire cores are twisted bodies; the conductor layer is composed of a plurality of regularly twisted braided conductors and an isolation tape layer (3) wrapped around the plurality of braided conductors, and the braided conductor is composed of an intermediate reinforcing core (1) and a conductor braided layer (2) braided outside the intermediate reinforcing core (1). The drag chain cable of the present invention has a highly flexible, anti-bending, and anti-tensile wire core, which can greatly reduce the problem of core breakage, and achieve the high comprehensive requirements of the drag chain cable such as high flexibility, anti-tensile, high-intensity load, and excellent electrical performance (data transmission).

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a highly flexible drag chain cable. Background Art

[0002] In recent years, with the continuous advancement of Industry 4.0 and the large-scale application of industrial robots, the drag chain cable industry has also ushered in a broader market prospect and unprecedented new opportunities. As an important part of the high-end equipment manufacturing industry, the drag chain cable has the characteristics of high technical content, strict use conditions, and high added value. It is widely used in ports, mining, steel, chemicals, automobiles, logistics, petrochemicals, packaging and other industries. As a connecting cable of the reel system in various underground mining mobile equipment, large lifting equipment, gantry cranes, portal, cantilever, bridge, rocker lifting equipment, marine grabs, garbage grabs, conveying and transportation equipment, collection machines, overhead cranes and mobile cranes. The relevant reel reel series requires frequent cable winding and cable release, and the drag chain cable laid in it has been in a dynamic winding state of continuous and frequent reciprocation. Under the condition of tens of thousands of reciprocations and friction, the cable is prone to problems such as conductor core breakage and sheath cracking. With the innovation of technology, the demand for developing a drag chain cable with high-strength tensile conductor is very urgent.

[0003] Since the conventional soft conductor structure of mobile cables has a great influence on the reliability of the cables and has a poor lifespan in actual use, the present invention is aimed at the actual application environment of existing drag chain cable conductors, with the aim of proposing a drag chain cable with high flexibility, anti-bending and anti-tensile properties, to solve the problem of core breakage that frequently occurs in the use of current mobile curved soft cables, and to achieve high comprehensive requirements such as high flexibility, tensile resistance, high-strength load, and excellent electrical performance (data transmission) of the cable. Summary of the invention

[0004] In order to solve the problem of frequent core breakage in drag chain cables, a highly flexible drag chain cable is provided. The drag chain cable of the present invention has a highly flexible, anti-bending and tensile-resistant core, which can greatly reduce the problem of core breakage and achieve the high comprehensive requirements of the drag chain cable such as high flexibility, tensile resistance, high-intensity load, and excellent electrical performance (data transmission).

[0005] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0006] A highly flexible drag chain cable, the structure of which from inside to outside includes: an insulating core, an inner sheath, a shielding layer, and an outer sheath;

[0007] The insulated wire core includes a conductor layer and an insulating layer from the inside to the outside, the number of the insulated wire cores is at least two, and the plurality of the insulated wire cores are twisted bodies;

[0008] The conductor layer is composed of a plurality of regularly twisted braided conductors and an isolation tape layer wrapped around the plurality of braided conductors, and the braided conductor is composed of a middle reinforcing core and a conductor braided layer braided outside the middle reinforcing core.

[0009] Furthermore, the intermediate reinforcing core is made of steel, and the conductor braided layers are all made of copper.

[0010] Furthermore, the middle reinforcing core is a steel wire with a diameter of 0.1 to 0.2 mm. Since the cable is subjected to more than 10 million times of drag chain tests, the cable itself must have sufficient strength. In addition to requiring sufficient mechanical strength for the raw materials constituting the cable, the overall insulation of the insulating core must also be designed to have good mechanical strength. The braided conductor of the present invention is designed with a fine steel wire reinforcing core in the middle, and the outer insulation of each core is designed with a fiber reinforcement layer woven from glass fiber fibers. Combined with the bulletproof wire braiding in the middle of the double-layer extruded sheath of the overall cable, on the one hand, the single and overall tensile strength of the cable is improved, and on the other hand, core slippage is avoided. Since the middle core is the part of the cable core that needs to withstand the most tension during the drag chain process, the possibility of the cable being broken is reduced.

[0011] Furthermore, the preparation method of the conductor layer is:

[0012] ① Using a braiding device, the steel wire is used as the intermediate reinforcing core and fixed as a lead wire, and multiple copper wires are divided into two parts of wire strands and introduced into the braiding device, so that the two parts of the wire strands make a cross sinusoidal motion on the periphery of the steel wire to braid to obtain the conductor braid layer, forming a braided conductor;

[0013] ② After obtaining a plurality of the braided conductors, the plurality of the braided conductors are twisted together according to the required number, and during the twisting process, they are subjected to multiple over-molding and compacting processes, and then wrapped and tied with a tape to form an isolation tape layer, and finally a conductor layer is obtained. There is an intermediate reinforcing core in the middle of the braided conductor. In order to prevent the central gap of the wire strand from being free during production, a steel wire is used as the intermediate core material of the braided conductor during the braiding process to play a role of reinforcement and tensile resistance. The intermediate reinforcing core can effectively ensure that the two parts of the wire strands are braided and attached to the outer layer of the intermediate reinforcing core; after multiple braided conductors are made, the multiple braided conductors are twisted into a complex body with a customized pitch of 25-35 times, and then wrapped and tied with an isolation tape. The complex body is molded and pressed during twisting. After pressing, the density of the conductor layer is guaranteed to form a high-strength tensile conductor; it can effectively avoid uneven force on the conductor when it moves and bends, and the force can be well transferred, decomposed and released, which greatly improves the conductor's high mechanical properties such as resistance to radial and longitudinal tension, and ensures the high flexibility and stability of the conductor while meeting the requirements of tensile strength and elongation, providing significant advantages for special torsion and bending tests of cables.

[0014] Furthermore, each of the insulating wire cores further includes a fiber reinforcement layer, wherein the fiber reinforcement layer is made by weaving glass fiber outside the insulating wire core. The fiber reinforcement layer has a protective function, strengthens the strength of the conductor layer, and meets the use environment of the drag chain.

[0015] Furthermore, the insulating layer, the inner protective layer and the outer protective layer are all made of elastomeric materials, which are coated by extrusion. The elastomeric materials may be POE, SEBS, TPE, TPO, TPV and the like.

[0016] Furthermore, the isolation tape layer is a polyester tape structure, which has the function of tightening and isolating the twisted braided conductors.

[0017] Furthermore, the shielding layer is a copper foil braided structure, and the structure of the copper foil is composed of a strip of copper foil and a bulletproof wire, and the strip of copper foil is evenly wrapped around the outer periphery of the bulletproof wire. The bulletproof wire is softer and has higher strength, which contributes to the high flexibility of the drag chain cable. The shielding layer of this structure protects the internal structure and can also play a role in cable shielding and anti-interference; the three-layer structure braided with the conductor and the insulation can meet the requirements of high radial and longitudinal tension resistance in special environments, and also meet the elasticity, softness and bending strength required by the cable during movement, greatly improving the service life of the cable's reciprocating motion.

[0018] Beneficial technical effects:

[0019] The present invention uses a braided conductor with an intermediate reinforcing core, which is twisted and then wrapped with a tape to form a conductor layer, and an insulating layer and a fiber reinforcing layer are extruded outside the conductor layer to form an insulated wire core. Multiple insulated wire cores are twisted and then an inner sheath is extruded to form a cable, and then a shielding layer is coated and an outer sheath is extruded to form a drag chain cable. The twisted conductor layer and the twisted insulating wire core of the present invention can effectively avoid uneven stress on the cable when it moves and bends, and can well transfer, decompose and release stress, greatly improve the high flexibility and stability of the cable, and enable the cable conductor to operate without trouble for a long time under the condition of a small bending radius, thereby ensuring stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the drag chain cable of Example 1.

[0021] Among them, 1-middle reinforcement core, 2-conductor braided layer, 3-isolation tape layer, 4-insulation layer, 5-fiber reinforcement layer, 6-inner sheath, 7-shielding layer, 8-outer sheath.

[0022] Figure 2 It is a schematic diagram of the conventional twisted wire core and the wire core of the present invention after bending. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0025] Conventional cables use soft Category 5 and Category 6 conductors for re-twisting to ensure the softness of the conductors. The thinner the conductor monofilament, the better the flexibility of the cable. However, if the conductor monofilament is too thin, it is easy to break. This type of conductor still has defects in high-intensity drag chains, movement, bending and other occasions. In order to increase the softness and flexibility of the cable, the cable core with a larger cross-section is generally made of multiple smaller diameter wires twisted together. The core of multiple twisted wires is relatively soft and has greater flexibility. As the cable is used in different occasions, the requirements for the flexibility of the core are also different. Special mobile drag chain cables are always in a dynamic winding state of continuous and frequent reciprocation. In the laying environment of thousands of reciprocating movements and back and forth friction, the requirements for the flexibility of the core are the highest.

[0026] Example 1

[0027] A highly flexible drag chain cable, the structure from inside to outside is as follows Figure 1 As shown, it includes in sequence: an insulating core, an inner sheath 6, a shielding layer 7, and an outer sheath 8;

[0028] The insulating wire core includes a conductor layer, an insulating layer 4, and a fiber reinforcement layer 5 from the inside to the outside. The number of the insulating wire cores can be as follows: Figure 1 The conventional 3 cores shown can also be up to 10 cores or more, and the most suitable number of cores can be designed according to actual needs; the plurality of insulated cores are twisted bodies;

[0029] The conductor layer is composed of a plurality of regularly twisted braided conductors and an isolation tape layer 3 wrapped around the plurality of braided conductors. The braided conductor is composed of a middle reinforcing core 1 and a conductor braided layer 2 braided outside the middle reinforcing core 1 .

[0030] The intermediate reinforcing core 1 is a steel wire with a diameter of 0.1 to 0.2 mm, and the conductor braided layer 2 is made of copper. The preparation method of the conductor layer is as follows:

[0031] (1) Using an 8-spindle braiding device, the steel wire is fixed as a lead wire, and 3 thin copper wires (single wire diameter 0.05 mm) are used as a spindle wire strand (in some embodiments, more thin copper wires may be used as a spindle wire strand), which are divided into upper 4 spindle wire strands and lower 4 spindle wire strands and introduced into the braiding device, and the braiding angles are set to 30° and 150°, so that the two parts of the wire strands make a cross sinusoidal motion on the periphery of the steel wire to braid the conductor braid layer 2, thereby forming a braided conductor;

[0032] (2) After obtaining a plurality of the braided conductors, seven of the braided conductors are twisted according to the required number (in some embodiments, the number of braided conductors may be 19 or 37, depending on the actual performance of the cable). This embodiment uses a 30-fold twisting pitch, and during the twisting process, multiple over-molding and pressing are performed to achieve the purpose of paralleling, forming, and pressing. Then, a polyester tape is used to wrap and bind the twisted plurality of braided conductors to form a conductor layer.

[0033] The fiber reinforcement layer 5 is made of glass fiber woven outside the insulating core. The fiber reinforcement layer has a protective effect and also plays an insulating role, strengthening the strength of the conductor layer to meet the use environment of the drag chain.

[0034] Among them, the materials of the insulating layer 4, the inner protective layer 6, and the outer protective layer 8 are all elastomeric materials, which are coated by extrusion. Specifically, in this embodiment, the material of the insulating layer 4 is TPO elastomer material, and the inner protective layer 6 and the outer protective layer 8 are both TPU elastomer material extruded sheaths.

[0035] Among them, the material of the shielding layer 7 is copper foil wire, and the structure of the copper foil wire is composed of strip copper foil and bulletproof wire. The strip copper foil is evenly wrapped around the outer periphery of the bulletproof wire. Compared with the copper foil wire obtained by general fiber wrapping, the bulletproof wire is softer and has higher strength, which contributes to the high flexibility of the drag chain cable.

[0036] The braided conductor of the present embodiment has an intermediate reinforcing core in the middle. In order to prevent the central gap of the wire strand from being free during production, a steel wire is used as the intermediate core material of the braided conductor during the braiding process to play a role of reinforcement and tensile resistance. The intermediate reinforcing core can effectively ensure that the two parts of the wire strands are braided and attached to the outer layer of the intermediate reinforcing core; after a plurality of braided conductors are made, the plurality of braided conductors are twisted into a complex body with a customized pitch and then wrapped and tied with an isolation tape. The complex body is molded and pressed during twisting. After pressing, the density of the conductor layer is ensured to form a high-strength tensile conductor; it can effectively avoid uneven force on the conductor when it moves and bends, and the force can be well transferred, decomposed and released, which greatly improves the mechanical properties of the conductor such as high resistance to radial and longitudinal tension, and further ensures that the conductor is highly flexible and stable while meeting the requirements of tensile strength and elongation, providing significant advantages for special torsion and bending tests of cables.

[0037] Embodiments 2 to 7

[0038] The drag chain cables of Examples 2 to 7 have the same structure as that of Example 1, except for the copper wire diameter and the number of braided strands of the conductor braided layer 2, as shown in Table 1. Examples 1-3 are braided using an 8-spindle braiding device; Examples 4-7 are braided using a 16-spindle braiding device.

[0039] Table 1 Differences in braided conductors of Examples 1-7

[0040]

[0041] Comparative Example 1

[0042] The cable structure of this comparative example is the same as that of Example 1, except that it does not have an intermediate reinforcing core 1, and the braided conductor is directly braided with copper wires.

[0043] Comparative Example 2

[0044] The cable structure of this comparative example is the same as that of Example 1, except that a braided conductor is not used, and conventional Category 6 conductors are twisted to form an insulated core.

[0045] Comparative Example 3

[0046] The cable structure of this comparative example is the same as that of Example 1, except that the shielding layer 7 is a conventional copper wire braided shielding layer.

[0047] Comparative Example 4

[0048] The cable structure of this comparative example is the same as that of Example 1, except that it does not have the fiber reinforcement layer 5 .

[0049] The cable performances of the above Examples 1-2 and Comparative Examples 1-4 are shown in Table 2. The tests in Table 2 were conducted in accordance with the current national standards for the cable industry.

[0050] Table 2 Cable properties of Examples 1-2 and Comparative Examples 1-4

[0051]

[0052] As can be seen from Table 1, the present invention can prevent the central gap of the wire strand from being free during production by adding an intermediate reinforcing core to the braided conductor. In the braiding process, steel wire is used as the intermediate core material of the braided conductor to play a role of reinforcement and tensile resistance. The intermediate reinforcing core can effectively ensure that the two parts of the wire strand are braided and attached to the outer layer of the intermediate reinforcing core; after multiple braided conductors are made, the multiple braided conductors are twisted into a complex body with a customized pitch and then wrapped and tied with an isolation tape. The complex body is molded and pressed during twisting. After pressing, the density of the conductor layer is ensured to form a high-strength tensile insulation core. In order to further strengthen the conductor strength to meet the use requirements of the drag chain environment, a fiber reinforcement layer of glass fiber braiding is coated on the outside of each insulating core; the inner and outer protective materials are extruded, and there is a shielding layer of strip copper foil wrapped with bulletproof wire between the inner and outer protective layers, so that the cable can meet the requirements of high radial and longitudinal tensile resistance in special environments, and can also meet the required elasticity, softness and bending strength of the cable during movement, greatly improving the service life of the cable reciprocating motion. The cable of the present invention can withstand torsional force of more than 10 million times (±180°) and has high strength; its flexibility can reach more than 30,000 reciprocating times and its bendability can reach more than 3 million times (±90°) bending.

[0053] The drag chain cable of the present invention can effectively avoid uneven force on the conductor when it moves and bends, and can transfer, decompose and release the force well, greatly improving the mechanical properties of the conductor such as high resistance to radial and longitudinal tension, and further ensuring the high flexibility and stability of the conductor while meeting the requirements of tensile strength and elongation, providing significant advantages for special torsion and bending tests of the cable.

[0054] Generally, when a metal wire is bent along a certain radius, the part outside the center line circle must be extended, and the part inside the circle must be shortened. If the core is composed of multiple wires twisted in a certain direction, the wires can slide between each other. Therefore, it is much more labor-saving than making the same bend with a single wire of the same cross-section. Figure 2 (a) represents a group of multiple conductors twisted in a certain direction (in Comparative Example 2, 6 types of conductors are twisted to form an insulated core with a cross section of Figure 2 (a)), after bending, it becomes Figure 2 As shown in (b), the thick bent wire is turned into a straight line. Figure 2As shown in (c), when a conventional twisted conductor becomes completely straight, bulges will appear on the surface of the core due to the plastic deformation of the conductor, which will distort the electric field distribution in the cable insulation layer and damage the cable insulation to reduce its stability, making it more likely that the conductor core of the cable will break frequently when used in drag chains, bending, etc.

[0055] In order to maintain the stability of the core structure and reduce the deformation of each conductor when the core is bent, the present invention twists the braided conductor with the middle reinforcing core and then wraps it with a tape to form a conductor layer, and extrudes an insulating layer and a fiber reinforcement layer outside the conductor layer to form an insulated core. The special core structure of the present invention is shown in FIG. Figure 2 As shown in (d), the bent rear piece Figure 2 As shown in (e), the inner and outer parts of the core center line can move and compensate each other, and the wire will not be deformed when bent. In addition, the core of the present invention can be distributed on a section of the core more smoothly when bent, and the cable insulation is not easily damaged when bent. Therefore, the drag chain cable with the core of the present invention has the advantages of high bendability, good flexibility and high stability.

[0056] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A highly flexible drag chain cable, characterized in that: The structure from inside to outside includes: an insulating core, an inner protective layer (6), a shielding layer (7), and an outer protective layer (8); The insulating wire core comprises a conductor layer and an insulating layer (4) in sequence from the inside to the outside, the insulating wire cores are at least two, and the plurality of insulating wire cores are in a twisted body structure; The conductor layer comprises, from the inside to the outside, a plurality of braided conductors and an isolation tape layer (3), the plurality of braided conductors are twisted together, and the structure of each braided conductor, from the inside to the outside, comprises, in sequence, an intermediate reinforcing core (1) and a conductor braided layer (2); The material of the intermediate reinforcing core (1) is steel, and the intermediate reinforcing core (1) is a steel wire with a diameter of 0.1 to 0.2 mm; the material of the conductor braided layer (2) is copper; the isolation tape layer (3) is a polyester tape; The preparation method of the conductor layer is: ① Using a braiding device, the steel wire is used as the intermediate reinforcing core (1) and fixed as a lead wire, and multiple copper wires are divided into two parts of wire strands and introduced into the braiding device, so that the two parts of the wire strands are braided in a cross-sinusoidal motion around the outer periphery of the steel wire to obtain the conductor braided layer (2), thereby forming a braided conductor; ② After obtaining a plurality of the braided conductors, the plurality of the braided conductors are twisted together according to the required number, and during the twisting process, they are pressed by overmolding for multiple times, and then wrapped and tied with a tape to form an isolation tape layer (3), and finally a conductor layer is obtained; The material of the insulating layer (4) is a TPO elastomer material, and the inner protective layer (6) and the outer protective layer (8) are both extruded sheaths made of a TPU elastomer material; Each of the insulating wire cores further comprises a fiber reinforcement layer (5) outside the insulating wire core, wherein the fiber reinforcement layer (5) is made by weaving glass fibers outside the insulating wire core; The shielding layer (7) is a copper foil braided structure, wherein the copper foil structure is composed of a strip-shaped copper foil and a bulletproof wire, and the strip-shaped copper foil is evenly wrapped around the outer periphery of the bulletproof wire.

Images