Flat cable for drag chain system and preparation method thereof

Abstract

The invention relates to the technical field of wires and cables, in particular to a flat cable for a drag chain system and a preparation method thereof.The flat cable comprises a cable core, an elastic filler and an outer sheath, the outer sheath forms a cable cavity on the outer side of the cable core and the elastic filler, the cable cavity is arranged on the single side of the axis of the outer sheath in an offset mode, and the elastic filler is arranged in the cable cavity. The outer sheath comprises a first sheath layer and a second sheath layer on the two sides of the cable cavity respectively, and the thickness of the first sheath layer is smaller than that of the second sheath layer; the cable core is arranged on one side of the bent center of the cable in an offset mode, the thickness of one side of the bent center of the sheath is smaller than that of the other side of the bent center of the sheath, and the elastic layer is arranged on the outer side of the cable core, so that the cable core has a larger activity space under the condition that the cable is bent, and pressure of the cable core on the sheath in the bent state is relieved. And when the sheath is in a bending state, the extrusion stress of one side of the bending center is reduced, and the thickness of the other side is relatively large, so that the wear resistance can be enhanced, and the overall service life of the cable sheath is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of electric wires and cables, and in particular to a flat cable for a drag chain system and a preparation method thereof. Background Art

[0002] Flat cable is a highly flexible flat cable specially used in drag chain systems. It has special design and manufacturing requirements. It uses ultra-fine oxygen-free bare copper wire finely twisted bundled cable conductors to ensure the cable's high softness and bending resistance to adapt to the frequent reciprocating movement and bending applications in drag chain systems.

[0003] The cable cores in existing flat cables are generally arranged in parallel at the center, and the outer sheath is directly covered on the outside of the cable core. The thickness of the sheath on the inside and outside of the cable core is basically the same. The cable is bent to one side in the drag chain system, and the sheath material on the inner side of the bend is squeezed, while the sheath material on the outer side of the bend is stretched. In addition, the outer side of the sheath will also rub against the drag chain, causing this part of the sheath to be easily broken and damaged, thereby reducing the overall service life of the cable. Summary of the invention

[0004] In view of the shortcomings of the prior art designs, the first aspect of the present invention provides a flat cable for a drag chain system, comprising:

[0005] The cable core comprises cable cores arranged parallel to each other and linearly;

[0006] Elastic filling, arranged on both sides of the cable core along the cable thickness direction;

[0007] An outer sheath, extruded and wrapped around the outer side of the cable core and the elastic filler;

[0008] The outer sheath forms a cable cavity on the outside of the cable core and the elastic filling. Along the thickness direction of the cable, the cable cavity is offset to a single side of the axis of the outer sheath, so that the outer sheath includes a first sheath layer and a second sheath layer on both sides of the cable cavity, and the thickness of the first sheath layer is less than the thickness of the second sheath layer. When the cable is bent, the core can move along the thickness direction of the cable in the cable cavity to reduce the pressure of the cable core on the outer sheath.

[0009] Preferably, a plurality of cavities are provided in the second sheath layer along the width direction of the cable, so that the second sheath layer can squeeze the cavities to deform in a bent state.

[0010] Preferably, the cross-section of the cavity is set to be rectangular, circular, oval or rounded triangle, and the multiple cavities are arranged in parallel with the cable core or the multiple cavities are alternately distributed along both sides of the parallel line of the cable core.

[0011] Preferably, a braided layer is provided inside the first sheath layer, and the braided layer includes a glass fiber braided mesh or an aramid fiber braided mesh.

[0012] Preferably, the thickness ratio of the second sheath layer to the first sheath layer is set to 2-3.

[0013] Preferably, a steel wire rope is provided at the junction of the first sheath layer and the second sheath layer, and the steel wire rope is symmetrically distributed on both sides of the cable core.

[0014] Preferably, the elastic filler includes a first elastic filler arranged between the cable core and the first sheath layer and a second elastic filler arranged between the cable core and the second sheath layer, and the thickness of the second elastic filler is greater than the thickness of the first elastic filler.

[0015] Preferably, the first elastic filler and the second elastic filler both comprise elastic filler strips, and the cross-section of the elastic filler strips is configured to be circular, elliptical or rounded triangle.

[0016] Preferably, the cable core comprises a first cable core and a second cable core which are arranged linearly in the width direction of the cable, wherein

[0017] The first cable core comprises at least two first cores distributed in parallel and a first coating layer coated on the outside of the first cores, and the first elastic filling / second elastic filling is distributed at any adjacent joints of two first cores and is located on the outside of the first coating layer;

[0018] The second cable core comprises at least two second cores distributed in parallel and a second coating layer coated on the outside of the second cores, and the first elastic filling / second elastic filling is distributed at the joints of any two adjacent second cores and is located on the outside of the second coating layer;

[0019] Preferably, the first elastic filler / the second elastic filler is distributed outside the joint between the first cable core and / or the second cable core.

[0020] A second aspect of the present invention provides a method for preparing a flat cable for a drag chain system, comprising the following steps:

[0021] Step 1: Prepare the cable core:

[0022] Step 1.1, preparing a first cable core, twisting annealed oxygen-free copper wires to form a first wire core, and coating the outer side of the first wire core with a first coating layer including insulation and / or shielding to form the first cable core;

[0023] Step 1.2, preparing a second cable core, twisting annealed oxygen-free copper wires to form a second wire core, and coating the outer side of the second wire core with a second coating layer including insulation and / or shielding to form a second cable core;

[0024] Step 1.3, arranging the first cable core and the second cable core in parallel on the same horizontal plane to form the cable core;

[0025] Step 2, preparing elastic filling, using an extruder to extrude elastic filling strips with a circular, elliptical or rounded triangle cross section to form the elastic filling;

[0026] Step 3: pre-positioning, placing the prepared elastic filling in parallel on the upper and lower sides of the cable core along the seam of the cable core, and arranging two steel wire ropes in parallel on both sides of the cable core, and arranging a glass or aramid fiber braided net in parallel on the lower side of the cable core;

[0027] Step 4: prepare an outer sheath by using an extruder to extrude a polyurethane (PUR / TPU) material to cover the cable core, elastic filling, steel wire rope and the outer side of the braided layer to form the outer sheath.

[0028] Compared with the prior art, the flat cable for a drag chain system and the preparation method thereof of the present invention have the following significant advantages:

[0029] The flat cable for a drag chain system of the present invention and the preparation method thereof bias the cable core to one side of the bend center of the cable bend, so that the thickness of the sheath on one side of the bend center is smaller than that on the other side, and an elastic layer is arranged on the outer side of the cable core, so that when the cable is bent, the cable core has a larger movable space to relieve the pressure of the cable core on the sheath in the bent state, and the extrusion stress of the sheath itself on one side of the bend center in the bent state is reduced, while the thickness of the other side is arranged to be relatively thick, which can enhance the wear resistance and extend the overall life of the cable sheath. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0031] Figure 1 1 is a schematic diagram of the end structure of a flat cable used in a drag chain system shown in an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the hierarchical structure of a flat cable used in a drag chain system shown in an embodiment of the present invention;

[0033] Figure 3 is a schematic cross-sectional structure diagram of a flat cable used in a drag chain system shown in an embodiment of the present invention;

[0034] Figure 4is a schematic cross-sectional structure diagram of a flat cable used in a drag chain system in a bent state as shown in an embodiment of the present invention;

[0035] 10. First cable core; 11. First wire core; 12. First covering layer; 20. Second cable core; 21. Second wire core; 22. Second covering layer; 30. Elastic filling; 31. First elastic filling; 32. Second elastic filling; 40. Outer sheath; 401. Cable cavity; 402. Cavity; 41. First sheath layer; 42. Second sheath layer; 50. Steel wire rope; 60. Braided layer. DETAILED DESCRIPTION

[0036] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0037] Since the flat cable is repeatedly bent and straightened only in the length direction (i.e., the axial direction of the cable), and the outer sheath of the current cable is tightly attached to the outside of the cable core, and the cable cores are also closely arranged, under frequent bending conditions, the bent outer edge of the cable sheath will be stretched and subjected to the outward squeezing force of the internal cable core, and the sheath will also continue to contact and rub against the drag chain. Therefore, the outer edge of the cable sheath is often damaged first, thereby reducing the service life of the entire cable. In order to improve the problem of easy damage to the sheath of the flat cable, the first aspect of the present invention proposes a flat cable for a drag chain system.

[0038] like Figure 1 As shown, the flat cable mainly includes a core, an elastic filler 30 and an outer sheath 40 .

[0039] The cable core includes parallel and linearly arranged cable cores, and the arrangement direction is the width direction of the cable.

[0040] In some embodiments, the cable core includes a first cable core 10 and a second cable core 20 arranged linearly in the width direction of the cable, wherein the first cable core 10 can be set as a signal cable core or a control cable core for transmitting electrical signals, and the first cable core 10 includes at least two parallel distributed first wire cores 11 and a first coating layer 12 coated on the outside of the first wire core 11.

[0041] Preferably, the first wire core 11 is formed by twisting a pair of twisted wires, and the first coating layer 12 includes a shielding layer woven of copper wires and an insulating layer extruded outside the shielding layer.

[0042] Furthermore, the second cable core 20 can be configured as a power cable core for transmitting electric energy. The second cable core 20 includes at least two second wire cores 21 distributed in parallel and a second coating layer 22 coated on the outside of the second wire cores 21 .

[0043] Preferably, the second core 21 is formed by twisting annealed oxygen-free copper wires, and the second coating layer 22 includes an inner lining layer and an insulating layer extruded outside the inner lining layer.

[0044] like Figure 1 and Figure 2 As shown, the elastic filling 30 is arranged on both sides of the cable core along the thickness direction of the cable, and the outer sheath 40 is extruded on the outer side of the cable core and the elastic filling 30. When the cable is bent, the wire core can squeeze the elastic filling 30 and obtain a certain activity space through the compressed elastic filling 30, thereby releasing a certain stress. In this way, the elastic filling 30 is arranged between the outer sheath 40 and the cable core, which can not only reduce the squeezing of the cable core on the outer sheath 40, but also reduce the stress concentration of the cable core in the bending state.

[0045] Since the flat cable is fixedly bent toward one side in the drag chain system, the sheath on the inner side of the bend and the sheath on the outer side of the bend are subjected to different stresses. The sheaths on the inner side of the bend squeeze each other in the length direction, while the sheaths on the outer side stretch each other in the length direction. It can be seen that reducing the thickness of the sheath on the inner side of the bend can reduce the force of mutual squeezing, while increasing the thickness of the sheath on the inner side of the bend can increase the life of the friction between the sheath and the drag chain.

[0046] like Figure 3 and Figure 4 As shown, the outer sheath 40 forms a cable cavity 401 on the outside of the cable core and the elastic filler 30. The shape of the cable cavity 401 is set to a rounded rectangle. The inner wall of the cable cavity 401 in the width direction abuts against the two sides of the cable core, and the cable cavity 401 abuts against the elastic fillers 30 on the upper and lower sides in the thickness direction. In addition, along the thickness direction of the cable, the cable cavity 401 is offset to a single side of the axis of the outer sheath 40. In this way, the outer sheath 40 presents different thicknesses on both sides of the cable core.

[0047] Furthermore, the outer sheath 40 includes a first sheath layer 41 and a second sheath layer 42 on both sides of the cable cavity 401, and the thickness of the first sheath layer 41 is less than the thickness of the second sheath layer 42, that is, the thickness of the sheath on the inner side of the bend is thinner, and the thickness on the other side is relatively thicker. When the cable is bent, the core can move in the cable cavity 401 along the cable thickness direction to reduce the pressure of the core on the outer sheath 40.

[0048] In a preferred embodiment, in order to partially release the tensile stress of the second sheath layer 42 when it is bent, a plurality of cavities 402 are provided in the second sheath layer 42 along the width direction of the cable, so that the second sheath layer 42 can squeeze the cavities 402 and deform when it is bent. In this way, when the second sheath layer 42 is bent outward, it can be compressed and thinned toward the center of the circle, thereby releasing the tensile stress. At the same time, there are support strips of a certain thickness between the cavities 402 (the part between the cavities 402), which can maintain the original thickness after bending.

[0049] Furthermore, the cross-section of the cavity 402 is set to be rectangular, circular, oval or rounded triangle, and multiple cavities 402 are arranged in parallel with the cable core or multiple cavities 402 are alternately distributed on both sides of the parallel lines of the cable core, wherein the thickness of the cavity 402 is set to be less than half the thickness of the second sheath layer 42 and is arranged on the side close to the cable core, so that the second sheath layer 42 has a certain elastic deformation while still having good wear resistance.

[0050] like Figure 3 and Figure 4 As shown, since the thickness of the first sheath layer 41 is relatively thin, it is easy to separate from the surface of the cable core and produce hollowing. In order to strengthen the first sheath layer 41 and limit the shape of the first sheath layer 41, a woven layer 60 is provided inside the first sheath layer 41. Optionally, the woven layer 60 is made of glass fiber woven mesh or aramid fiber woven mesh. The glass fiber woven mesh or aramid fiber woven mesh is embedded in the first sheath layer 41. On the one hand, the tensile strength of the first sheath layer 41 can be enhanced, and the shape of the first sheath layer 41 can be maintained under high-frequency bending conditions, so that the first sheath layer 41 is always attached to the outside of the cable core.

[0051] Furthermore, the thickness ratio of the second sheath layer 42 to the first sheath layer 41 is set to 2 to 3, that is, the thickness of the second sheath layer 42 is two to three times the thickness of the first sheath layer 41, which can enhance the overall wear resistance of the cable sheath and reduce its own stress concentration during bending, thereby increasing the service life of the sheath.

[0052] Furthermore, in order to enhance the overall tensile strength of the cable and protect the outer sheath 40 and the cable core, a steel wire rope 50 is provided at the junction of the first sheath layer 41 and the second sheath layer 42, and the steel wire rope 50 is symmetrically distributed on both sides of the cable core.

[0053] In some embodiments, the elastic filler 30 includes a first elastic filler 31 arranged between the cable core and the first sheath layer 41 and a second elastic filler 32 arranged between the cable core and the second sheath layer 42, wherein the first elastic filler 31 and the second elastic filler 32 can both adopt elastic filling strips made of polyurethane material, and the cross-section of the elastic filling strip is set to be circular, elliptical or rounded triangle.

[0054] Among them, the elastic filling strips are distributed at the joints of any two adjacent wire cores or cable cores, which can maintain the position of the cable core, and the elastic filling strips can be compressed to give the cable core a larger activity space to reduce the pressure of the cable core on the sheath when the cable core is in a bent state.

[0055] Furthermore, the thickness of the second elastic filler 32 is greater than that of the first elastic filler 31, so that when the cable as a whole is in a bent state, the second elastic filler 32 can still contact the second sheath layer 42 and the cable core part, thereby preventing the second elastic filler 32 from being suspended between the second sheath layer 42 and the cable core and causing the core to shift.

[0056] In combination with the above embodiments, the cable core is biased to the side of the bend center of the cable bend, so that the thickness of the sheath on one side of the bend center is smaller than the other side, and an elastic layer is arranged on the outside of the cable core, so that when the cable is bent, the cable core has a larger activity space to reduce the pressure of the cable core on the outer sheath 40 in the bent state, and the extrusion stress of the outer sheath 40 itself on one side of the bend center in the bent state is reduced, while the thickness of the other side is relatively thick, which can enhance the wear resistance and increase the overall life of the outer sheath 40.

[0057] A second aspect of the present invention provides a method for preparing a flat cable for a drag chain system, comprising the following steps:

[0058] Step 1: Prepare the cable core:

[0059] Step 1.1, prepare the first cable core 10. Taking the first cable core 10 as a signal cable core or a control cable core as an example, annealed oxygen-free copper wires are twisted to form a first core 11, and a first coating layer 12 including insulation and / or shielding is coated on the outside of the first core 11 to form the first cable core 10. The first coating layer 12 includes a shielding layer woven of copper wires and an insulating layer extruded on the outside of the shielding layer. The first cable core 10 is mainly used to transmit electrical signals.

[0060] Step 1.2, prepare the second cable core 20. Taking the second cable core 20 as a power cable core as an example, annealed oxygen-free copper wires are twisted to form a second core 21, and the outer side of the second core 21 is coated with an insulating second coating layer 22 to form the second cable core 20. The second cable core 20 is mainly used to transmit electrical energy.

[0061] Step 1.3: Arrange the first cable core 10 and the second cable core 20 in parallel on the same horizontal plane to form a cable core.

[0062] Step 2: prepare the elastic filler 30 , and use an extruder to extrude polyurethane material to form an elastic filler strip with a circular, elliptical or rounded triangle cross section to make the elastic filler 30 .

[0063] Step 3: pre-positioning, placing the prepared elastic filler 30 in parallel on the upper and lower sides of the cable core along the seam of the cable core, and arranging two steel wire ropes 50 in parallel on both sides of the cable core, and arranging a glass or aramid fiber braided net in parallel on the lower side of the cable core;

[0064] Step 4: prepare the outer sheath 40 , and use an extruder to extrude a polyurethane (PUR / TPU) material to cover the cable core, the elastic filler 30 , the steel wire rope 50 and the braided layer 60 to form the outer sheath 40 .

[0065] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A flat cable for a drag chain system, It is characterized in that include: A plurality of cable cores, including cable cores arranged parallel to each other and linearly; Elastic fillers (30) are arranged on both sides of the cable core along the thickness direction of the cable; An outer sheath (40) is extruded and wrapped around the outer sides of the cable core and the elastic filler (30); The outer sheath (40) forms a cable cavity (401) on the outside of the cable core and the elastic filler (30); along the thickness direction of the cable, the cable cavity (401) is offset to one side of the axis of the outer sheath (40), so that the outer sheath (40) includes a first sheath layer (41) and a second sheath layer (42) on both sides of the cable cavity (401), and the thickness of the first sheath layer (41) is smaller than the thickness of the second sheath layer (42); when the cable is bent, the cable core can move in the cable cavity (401) along the thickness direction of the cable, so as to reduce the pressure of the cable core on the outer sheath (40).

2. The flat cable for a drag chain system according to claim 1, It is characterized in that A plurality of groups of cavities (402) are provided in the second sheath layer (42) along the width direction of the cable, so that the second sheath layer (42) can squeeze the cavities (402) to deform in a bent state.

3. The flat cable for a drag chain system according to claim 2, It is characterized in that The cross-section of the cavity (402) is set to be rectangular, circular, oval or rounded triangle, and a plurality of the cavities (402) are arranged in parallel with the cable core or the plurality of the cavities (402) are alternately distributed along both sides of the parallel line of the cable core.

4. The flat cable for a drag chain system according to claim 1, It is characterized in that A braided layer (60) is provided inside the first sheath layer (41), and the braided layer (60) comprises a glass fiber braided mesh or an aramid fiber braided mesh.

5. The flat cable for a drag chain system according to any one of claims 1 to 4, It is characterized in that The thickness ratio of the second sheath layer (42) to the first sheath layer (41) is set to 2-3.

6. The flat cable for a drag chain system according to claim 5, It is characterized in that A steel wire rope (50) is provided at the junction of the first sheath layer (41) and the second sheath layer (42), and the steel wire rope (50) is symmetrically distributed on both sides of the cable core.

7. The flat cable for a drag chain system according to claim 1, It is characterized in that The elastic filler (30) comprises a first elastic filler (31) arranged between the cable core and the first sheath layer (41) and a second elastic filler (32) arranged between the cable core and the second sheath layer (42), and the thickness of the second elastic filler (32) is greater than the thickness of the first elastic filler (31).

8. The flat cable for a drag chain system according to claim 7, It is characterized in that The first elastic filler (31) and the second elastic filler (32) both comprise elastic filling strips, and the cross-section of the elastic filling strips is arranged to be circular, elliptical or rounded triangle.

9. The flat cable for a drag chain system according to claim 7, It is characterized in that The cable core comprises a first cable core (10) and a second cable core (20) which are arranged linearly in the width direction of the cable, wherein The first cable core (10) comprises at least two first wire cores (11) arranged in parallel and a first coating layer (12) coated on the outside of the first wire core (11); the first elastic filler (31) / the second elastic filler (32) is distributed at the joint of any two adjacent first wire cores (11) and is located on the outside of the first coating layer (12); The second cable core (20) comprises at least two second cores (21) arranged in parallel and a second coating layer (22) coated on the outside of the second cores (21); the first elastic filler (31) / second elastic filler (32) is distributed at the joint of any two adjacent second cores (21) and is located on the outside of the second coating layer (22); The first elastic filler (31) / the second elastic filler (32) is distributed outside the joint between the first cable core (10) and / or the second cable core (20).

10. The method for preparing the flat cable for a drag chain system according to claim 1, It is characterized in that The following steps are involved: Step 1: Prepare the cable core: Step 1.1, preparing a first cable core (10), twisting annealed oxygen-free copper wires to form a first wire core (11), and coating the outer side of the first wire core (11) with a first coating layer (12) including insulation and / or shielding to form the first cable core (10); Step 1.2, preparing a second cable core (20), twisting annealed oxygen-free copper wires to form a second wire core (21), and coating the outer side of the second wire core (21) with a second coating layer (22) including insulation and / or shielding to form the second cable core (20); Step 1.3, arranging the first cable core (10) and the second cable core (20) in parallel on the same horizontal plane to form the cable core; Step 2, preparing the elastic filling (30), using an extruder to extrude an elastic filling strip having a circular, elliptical or rounded triangle cross section to form the elastic filling (30); Step 3: pre-positioning, placing the prepared elastic filler (30) in parallel on the upper and lower sides of the cable core along the seam of the cable core, and arranging two steel wire ropes (50) in parallel on both sides of the cable core, and arranging a glass or aramid fiber braided net in parallel on the lower side of the cable core; Step 4: prepare an outer sheath (40), and use an extruder to extrude a sheath material to cover the outer side of the cable core, the elastic filler (30), the steel wire rope (50) and the braided layer (60) to form the outer sheath (40).

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