Green bending-resistant power cable

Abstract

The application provides a kind of green bending-resistant power cable, belongs to cable technical field, the green bending-resistant power cable, including conductor, the outer surface of conductor is fixedly connected with insulating layer, the outer surface of insulating layer is provided with filling layer, the outer surface of filling layer is provided with physical protection layer;Engaging structure is arranged between insulating layer and filling layer, and insulating layer and filling layer are engaged with each other through engaging structure, and engaging structure is used to prevent insulating layer and filling layer from sliding with each other.The application is provided with conductor, insulating layer, filling layer and engaging structure, when the cable is bent and deformed, the insulating layer and the filling layer are constrained by the engaging structure, and the relative sliding between the two does not occur;When the cable is bent, it needs to adapt to the deformation requirement with a larger bending radius, the engaging structure increases the actual bending radius of the cable, reduces the bending stress of the material at the bending part, effectively relieves the material fatigue problem, and improves the service life of the cable.

Description

Technical Field

[0001] This invention belongs to the field of cable technology, specifically relating to a green, bend-resistant power cable. Background Technology

[0002] Power cables are mainly used for the transmission and distribution of electrical energy. They generally consist of a conductor, an insulation layer, a filler layer, and an outer sheath. The conductor carries electrical energy or signals; the insulation layer covers the outside of the conductor, providing electrical isolation between conductors and from the outside; the filler layer is placed outside the insulation layer, serving as a buffer against stress; the outermost sheath protects the inner conductor from external friction, compression, moisture, oil, and other environmental damage.

[0003] Currently, in industrial equipment such as tank chains, overhead crane trolleys, and robotic arms, power cables need to continuously reciprocate with the equipment, enduring repeated bending over long periods. Traditional cables lack a restraining structure between their insulation and filler layers. During bending, these layers are prone to relative slippage, resulting in an excessively small bending radius. This increases the burden on the material covering the conductor, and prolonged repeated bending can easily cause cable material fatigue, potentially leading to internal conductor breakage and shortening the overall lifespan of the cable.

[0004] Therefore, in order to solve the problem of material fatigue caused by reciprocating bending during cable use, a green, bend-resistant power cable is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a green, bend-resistant power cable, which aims to solve the problem of material fatigue caused by reciprocating bending during cable use in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A green, bend-resistant power cable includes a conductor, an insulation layer fixedly connected to the outer surface of the conductor, a filler layer disposed on the outer surface of the insulation layer, and a physical protective layer disposed on the outer surface of the filler layer; an interlocking structure is provided between the insulation layer and the filler layer, the insulation layer and the filler layer are interlocked with each other through the interlocking structure, the interlocking structure is used to prevent the insulation layer and the filler layer from sliding against each other.

[0007] As a further aspect of the present invention: the meshing structure includes a groove formed on the outer surface of the insulating layer and a protrusion fixedly disposed on the inner sidewall of the filling layer. The protrusion of the filling layer is embedded in the groove of the insulating layer to realize the meshing of the insulating layer and the filling layer.

[0008] As a further aspect of the present invention: the filling layer and the protrusion are integrally manufactured and both are made of shape memory material.

[0009] As a further aspect of the present invention: after the protrusion and the groove engage, a deformation gap is reserved between the inner bottom wall of the groove and the top surface of the protrusion.

[0010] As a further aspect of the present invention: the physical protective layer includes an inner layer, an armor layer, and a woven outer sheath.

[0011] As a further aspect of the present invention: a plurality of radial tubes are fixedly connected in the radial direction within the filling layer, the bottom end of the radial tubes is connected to the groove, and the top end of the radial tubes passes through the inner layer and is connected to the armor layer.

[0012] As a further aspect of the present invention: both the groove and the protrusion are spirally arranged along the length direction, and the end face of the filling layer is provided with a plurality of longitudinal grooves along the length direction. The longitudinal grooves are all connected to each spiral groove, and the bottom end of the radial tube is connected to the corresponding longitudinal groove.

[0013] As a further aspect of the present invention: the armor layer is made of ultra-thin stainless steel sheets interlaced and woven together, with a gap reserved at the top of the radial tube for passage.

[0014] As a further aspect of the present invention: the woven outer sheath is made of a mixture of breathable polyester fiber and wear-resistant polypropylene fiber, and the woven structure is breathable.

[0015] As a further aspect of the present invention, thermally conductive silicone grease is applied to the inner bottom wall of the groove.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, by setting up a conductor, an insulation layer, a filler layer, and an interlocking structure, ensures that when the cable undergoes bending deformation, the insulation layer and the filler layer are mutually constrained by the interlocking structure, preventing relative slippage between them. When the cable bends, a larger bending radius is required to accommodate the deformation. The interlocking structure increases the actual bending radius of the cable, reduces the bending stress on the material at the bending point, effectively alleviates material fatigue problems, and improves the service life of the cable.

[0017] 2. By setting up an insulation layer, a filling layer, a protrusion, a radial tube, and a braided outer sheath, the present invention creates a negative pressure when the cable is in continuous reciprocating bending applications. The gap between the protrusion and the groove increases, creating negative pressure. Outside air passes through the braided outer sheath into the radial tube, and then into the gap between the protrusion and the groove. When the gap between the protrusion and the groove decreases, the air between the protrusion and the groove is squeezed into the radial tube and escapes to the outside through the braided outer sheath, thus achieving the function of heat dissipation of the cable. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the right-side structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the braided outer sheath in this invention; Figure 4 This is a schematic diagram of the internal three-dimensional structure of the inner layer and the filling layer of the present invention; Figure 5 For the present invention Figure 4 A magnified schematic diagram of the structure at point A in the diagram.

[0019] In the diagram: 1. Conductor; 2. Insulating layer; 3. Filling layer; 4. Groove; 5. Protrusion; 6. Deformation gap; 7. Inner layer; 8. Armor layer; 9. Braided outer sheath; 10. Radial tube; 11. Longitudinal groove; 12. Chamfer; 13. Thermal grease; 14. Semiconductor layer. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 — Figure 5 The present invention provides the following technical solution: a green bend-resistant power cable, comprising a conductor 1, an insulation layer 2 fixedly connected to the outer surface of the conductor 1, a filling layer 3 disposed on the outer surface of the insulation layer 2, and a physical protective layer disposed on the outer surface of the filling layer 3; an interlocking structure is provided between the insulation layer 2 and the filling layer 3, the insulation layer 2 and the filling layer 3 interlocking with each other through the interlocking structure, the interlocking structure being used to prevent the insulation layer 2 and the filling layer 3 from sliding against each other, so as to increase the bending radius of the cable when it is bent.

[0022] In cable applications, such as cable routing on tank tracks, lateral reciprocating movement of overhead crane trolleys, and robotic arm movements, cables need to be continuously bent back and forth with the equipment. Long-term repeated bending can easily cause fatigue of the cable material and even lead to the fracture and failure of the internal conductor.

[0023] In the technical solution of this application, when the cable undergoes bending deformation, the insulation layer 2 and the filler layer 3 are mutually constrained by an interlocking structure, preventing relative slippage between them. When the cable bends, a larger bending radius is required to accommodate the deformation. This interlocking structure increases the actual bending radius of the cable, reduces the bending stress on the material at the bending point, effectively alleviates material fatigue problems, and improves the service life of the cable.

[0024] In this embodiment, the meshing structure includes a groove 4 formed on the outer surface of the insulating layer 2 and a protrusion 5 fixedly disposed on the inner sidewall of the filling layer 3. The protrusion 5 of the filling layer 3 is embedded in the groove 4 of the insulating layer 2 to achieve meshing between the insulating layer 2 and the filling layer 3 and prevent the insulating layer 2 and the filling layer 3 from sliding relative to each other.

[0025] When the cable is bent, the insulation layer 2 and the filler layer 3 cannot slide relative to each other, increasing the bending radius of the cable. However, this also increases the shear stress between the insulation layer 2 and the filler layer 3. If the insulation layer 2 and the filler layer 3 are too firmly fixed, the interlayer shear stress cannot be released, resulting in stress concentration at the bending point and causing material cracking. To solve this problem, in this embodiment, the filler layer 3 and the protrusion 5 are integrally manufactured using shape memory material, which is halogen-free modified foamed EPDM, also known as ethylene propylene diene monomer (EPDM) rubber. EPDM rubber is composed of EPDM matrix, halogen-free flame retardants (aluminum hydroxide, magnesium hydroxide), foaming agent (azodicarbonamide), and plasticizer (epoxidized soybean oil). It has a Shore hardness of 30-40, a foaming ratio of 3-5 times, an elongation at break ≥400%, is halogen-free and low-smoke, and has bending fatigue resistance ≥3×10⁻⁶. 6 Secondly, EPDM rubber has excellent high elasticity, which allows the protrusion 5 to flexibly engage with the groove 4 of the insulation layer 2. During bending, it adapts to the bending action of the cable through its own slight deformation, which significantly reduces the shear stress between the insulation layer 2 and the filler layer 3.

[0026] Its working principle is as follows: When the cable bends, the outer radius of the bend is larger and the inner radius is smaller. The insulation layer 2 and the filler layer 3 on the outer side of the bend are under tension. The filler layer 3, relying on its high elasticity, generates a rebound force after being stretched, inhibiting further stretching of the outer side of the filler layer 3 (the protrusion 5 has the same function). Meanwhile, the filler layer 3 on the inner side of the bend is subjected to compression and deforms. After being compressed, it generates an outward expansion force, limiting further compression of the inner side of the filler layer 3 (the protrusion 5 has the same function). Thus, the filler layer 3 plays a role in buffering and constraining deformation during cable bending, thereby increasing the bending radius. Compared with a rigid meshing structure, this solution has a limited increase in the cable bending radius, but compared with the structure in ordinary cables where the insulation layer 2 and the filler layer 3 can slip relative to each other, it can still significantly increase the cable bending radius and greatly eliminate the internal shear stress generated during cable bending. The meshing structure is a flexible meshing structure, allowing the protrusion 5 to deform and adapt to the bending during bending. However, because the protrusion 5 has elasticity, it also restricts the bending to a certain extent, resulting in a larger bending radius ratio.

[0027] In this embodiment, the shape memory material is shape memory foamed polyurethane (SMPU), and the triggering temperature is controlled by adjusting the ratio of hard segments (polyurethane segments) and soft segments (polyether and polyester segments) in the SMPU molecular chain. Hard segment ratio 30%-40%: trigger temperature 30-40℃, suitable for medical equipment and low-temperature scenarios; Hard segment ratio 40%-50%: trigger temperature 40-60℃, suitable for mainstream mass production scenarios such as industrial robots and new energy vehicles (fully matched with the working heating temperature of cable conductor 1 35-55℃). Hard segment ratio 50%-60%: trigger temperature 60-80℃, suitable for high-temperature scenarios such as industrial furnaces and metallurgical equipment.

[0028] SMPU remains unchanged after deformation below the trigger temperature, which facilitates winding and transportation. If the elasticity is too high, the cable will not be firmly fixed after winding, and there is a risk of it breaking. During use, the appropriate trigger temperature is selected according to the application environment so that when the cable is in normal use, SMPU reaches the trigger temperature, so that SMPU will automatically recover after deformation. It has the characteristics of halogen-free modified foamed EPDM, so that the protrusion 5 and the groove 4 are flexibly engaged, which plays a role in buffering and restraining deformation.

[0029] In this embodiment, after the protrusion 5 and the groove 4 engage, a deformation gap 6 is reserved between the inner bottom wall of the groove 4 and the top surface of the protrusion 5 to accommodate the deformation of the protrusion 5 and the groove 4.

[0030] In this embodiment, the physical protective layer includes an inner layer 7, an armor layer 8, and a woven outer sheath 9.

[0031] In this embodiment, a plurality of radial tubes 10 are fixedly connected in the radial direction inside the filling layer 3. The bottom end of the radial tube 10 is connected to the groove 4, and the top end of the radial tube 10 passes through the inner layer 7 and is connected to the armor layer 8.

[0032] In applications where the cable undergoes continuous reciprocating bending, the insulation layer 2 and the filler layer 3 repeatedly bend, causing the protrusion 5 to be continuously stretched and compressed. On the outer side of the bend, the protrusion 5 is stretched, increasing the gap between the protrusion 5 and the groove 4; on the inner side of the bend, the protrusion 5 is compressed, decreasing the gap between the protrusion 5 and the groove 4. Therefore, the gap between the protrusion 5 and the groove 4 repeatedly increases and decreases. The internal air communicates with the armor layer 8 through the radial tube 10, and the armor layer 8 is connected to the outside environment through the braided outer sheath 9. The connection creates a circulation between the internal and external air of the cable. The gap between the protrusion 5 and the groove 4 widens, creating a negative pressure. External air passes through the braided outer sheath 9 into the radial tube 10, and then into the gap between the protrusion 5 and the groove 4. The gap between the protrusion 5 and the groove 4 narrows, and the air between them is squeezed into the radial tube 10 and escapes to the outside through the braided outer sheath 9. The heat dissipation capacity of the flowing air is far superior to that of solid materials. The air carries away a large amount of heat from the inside of the cable, thus achieving the function of heat dissipation.

[0033] In this embodiment, both the groove 4 and the protrusion 5 are spirally arranged along the length direction. The end face of the filling layer 3 is provided with a plurality of longitudinal grooves 11 along the length direction. Each longitudinal groove 11 is connected to each spiral groove 4. The bottom end of the radial tube 10 is connected to the corresponding longitudinal groove 11, thereby achieving the purpose of connecting the bottom end of the radial tube 10 to the groove 4 through the longitudinal groove 11.

[0034] During use, the gap between the protrusion 5 and the groove 4 increases, creating a negative pressure. Outside air passes through the braided outer sheath 9 and enters the radial tube 10, then enters the gap between the protrusion 5 and the groove 4 through the longitudinal groove 11. When the gap between the protrusion 5 and the groove 4 decreases, the air between the protrusion 5 and the groove 4 is first squeezed into the longitudinal groove 11 and then enters the radial tube 10 and escapes to the outside through the braided outer sheath 9, thus achieving the function of heat dissipation.

[0035] In this embodiment, the edge of the groove 4 is chamfered 12 to facilitate the assembly of the filling layer 3 and the insulating layer 2; the filling layer 3 and the protrusion 5 are pre-formed as a whole, and the insulating layer 2 is pre-formed with the groove 4. Then the insulating layer 2 is screwed into the filling layer 3 so that each protrusion 5 engages with the corresponding groove 4.

[0036] In this embodiment, the inner bottom wall of the groove 4 is coated with thermal grease 13, which has the function of heat dissipation. The heat of the conductor 1 is conducted to the insulating layer 2, and the heat of the insulating layer 2 is transferred to the air between the protrusion 5 and the groove 4 through the silicone. Then the air exchanges heat with the outside world to achieve the purpose of heat dissipation.

[0037] In this embodiment, a semiconducting layer 14 is fixedly connected between the conductor 1 and the insulating layer 2. The resistivity of the semiconducting layer 14 is between that of a metal conductor and an insulator. It does not carry current, but can uniformize the electric field, suppress partial discharge, and protect the main insulation.

[0038] In this embodiment, the inner layer 7 is fixedly connected to the outside of the filling layer 3, the armor layer 8 covers the outside of the inner layer 7, and the braided outer sheath 9 covers the outside of the armor layer 8. The inner layer 7 is a halogen-free low-smoke material, specifically a halogen-free flame-retardant polyolefin HFFR, which is a halogen-free low-smoke flame-retardant polyolefin composite material. It does not contain halogens such as chlorine, bromine, and fluorine. It uses polyolefin as the matrix and is compounded with a halogen-free flame-retardant system, which has the three major characteristics of insulation, flame retardancy, and environmental protection.

[0039] In this embodiment, the armor layer 8 is made of ultra-thin stainless steel sheets woven in an alternating manner, with a gap reserved for the top of the radial tube 10 to pass through; ultra-thin 304 stainless steel sheets with a thickness of 0.05-0.1mm are used and cut into rectangles with a width of 5-10mm; they are wrapped around the outside of the cable in an alternating manner, with adjacent sheets overlapping by 1-2mm to form a flexible structure similar to scales; the edges of the sheets are rounded to reduce friction and wear during bending, improve bending resistance, and increase compressive strength; the reserved gap allows for the fixing ring to be fixedly embedded in the stainless steel sheet, and the top of the radial tube 10 is fitted inside the fixing ring.

[0040] The bottom end of the radial tube 10 is connected to the longitudinal groove 11, and the top end of the radial tube 10 is inserted into the gap reserved in the armor layer 8 and is connected to the braided outer sheath 9.

[0041] In cable production, after the armor layer 8 is completed, the radial tube 10 is inserted into the gap reserved in the armor layer 8, then the inner layer 7 is inserted, and then the filler layer 3 is inserted until the bottom end of the radial tube 10 enters the longitudinal groove 11, and then the braided outer sheath 9 is covered.

[0042] In this embodiment, the woven outer sheath 9 is made of breathable polyester fiber with micron-level pores, and polypropylene wear-resistant fiber is mixed in a 2:1 ratio. The weaving structure is a twill breathable weave. The weaving density is controlled at 70%-80%, ensuring both breathability and basic wear resistance and dustproof performance. It covers the outermost layer. Although the woven outer sheath 9 has dustproof performance, its resistance to water vapor is relatively low. To solve this problem, a waterproof and breathable membrane is fixed inside the radial tube 10. The working principle of the waterproof and breathable membrane is as follows: the distance between gas molecules is relatively large, and they can pass through the pores of the waterproof and breathable membrane during diffusion. The distance between liquid molecules is smaller than the distance between the pores, and under the action of surface tension, liquid molecules cannot pass through the waterproof and breathable membrane, thus achieving a waterproof function. During use, it prevents droplets in the outside air from entering the longitudinal groove 11 through the radial tube 10, thus achieving a moisture-proof function. The main types include polytetrafluoroethylene (PTFE) membranes, etc.

[0043] In this embodiment, the insulation layer 2 is made of low-smoke halogen-free XLPO cross-linked polyolefin material. The matrix is ​​a blend of polyethylene, EVA, and POE polyolefin, compounded with a halogen-free flame-retardant metal hydroxide system. It is cross-linked by irradiation to form a three-dimensional network thermosetting structure. The material does not contain halogen elements, has high light transmittance of combustion flue gas, and does not release corrosive halogen acid gas. It has both excellent insulation performance and heat resistance and anti-aging performance. The heavy metal content meets RoHS environmental protection requirements.

[0044] The working principle of this invention is as follows: In applications where the cable undergoes continuous reciprocating bending, the insulation layer 2 and the filling layer 3 continuously bend, and the protrusion 5 is continuously stretched and compressed. On the outer side of the bend, the protrusion 5 is stretched, which increases the gap between the protrusion 5 and the groove 4. On the inner side of the bend, the protrusion 5 is compressed, which decreases the gap between the protrusion 5 and the groove 4. The increased gap between the protrusion 5 and the groove 4 creates a negative pressure, allowing outside air to pass through the braided outer sheath 9 into the radial tube 10, and then into the gap between the protrusion 5 and the groove 4. As the gap between the protrusion 5 and the groove 4 decreases, the air between the protrusion 5 and the groove 4 is forced into the radial tube 10 and escapes to the outside through the braided outer sheath 9. The air carries away a large amount of heat from inside the cable, thus achieving heat dissipation.

[0045] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A green, bend-resistant power cable, characterized in that: It includes a conductor, an insulating layer fixedly connected to the outer surface of the conductor, a filling layer on the outer surface of the insulating layer, and a physical protective layer on the outer surface of the filling layer; an interlocking structure is provided between the insulating layer and the filling layer, and the insulating layer and the filling layer are interlocked with each other through the interlocking structure, which is used to prevent the insulating layer and the filling layer from sliding against each other.

2. The power cable according to claim 1, characterized in that: The meshing structure includes a groove formed on the outer surface of the insulating layer and a protrusion fixedly disposed on the inner sidewall of the filling layer. The protrusion of the filling layer is embedded in the groove of the insulating layer to achieve meshing between the insulating layer and the filling layer.

3. The power cable according to claim 2, characterized in that: The filling layer and the raised part are manufactured as a single piece, both using shape memory material.

4. The power cable according to claim 3, characterized in that: After the protrusion and the groove engage, a deformation gap is reserved between the inner bottom wall of the groove and the top surface of the protrusion.

5. The power cable according to claim 4, characterized in that: The physical protective layer consists of an inner layer, an armor layer, and a woven outer sheath.

6. The power cable according to claim 5, characterized in that: Several radial tubes are fixedly connected in the radial direction within the filling layer. The bottom end of the radial tube is connected to the groove, and the top end of the radial tube passes through the inner layer and is connected to the armor layer.

7. The power cable according to claim 6, characterized in that: Both the grooves and protrusions are spirally arranged along the length direction. The end face of the filling layer has several longitudinal grooves along the length direction. The longitudinal grooves are connected to each spiral groove. The bottom end of the radial tube is connected to the corresponding longitudinal groove.

8. The power cable according to claim 6, characterized in that: The armor layer is made of ultra-thin stainless steel sheets interlaced and woven together, with a gap reserved at the top of the radial tube for passage.

9. The power cable according to claim 5, characterized in that: The woven outer sheath is made of a blend of breathable polyester fiber and abrasion-resistant polypropylene fiber, and the woven structure is breathable.

10. The power cable according to claim 2, characterized in that: The inner bottom wall of the groove is coated with thermal grease.

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