A low-voltage power cable with breakage prevention

Abstract

The application relates to the technical field of low-voltage power cables, and discloses a low-voltage power cable capable of preventing breakage, which comprises a cable main body, a plurality of fixed connection nodes are arranged on the outer periphery of the cable main body at intervals along the axial direction, each fixed connection node is fixed to the cable main body, and at least one movable ring capable of being deflected relative to the fixed connection node is arranged on each fixed connection node, the movable ring is connected with the fixed connection node through an elastic connecting piece, so that the movable ring can be deflected relative to the fixed connection node when the movable ring is subjected to external force and can be reset after the external force is removed; the movable ring abuts against the fixed connection node when reaching a limit deflection position; when the cable is bent, the connecting cord on the outer bending side is first tensioned, the movable ring continues to be deflected, then the stop portion abuts against the deflection limiting surface, and the included angle between the adjacent fixed connection nodes is limited to continue to increase.

Description

Technical Field

[0001] This invention relates to the field of mechanical protection technology for power cables, specifically to a low-voltage power cable that is resistant to breakage. Background Technology

[0002] Low-voltage power cables are used for power transmission between distribution equipment, electrical equipment, and mobile mechanisms. Cables often need to change their routing at equipment inlets, cable chain outlets, cabinet corners, narrow cable trays, and mobile power supply locations, and may be subjected to repeated lateral swinging, dragging, or localized compression. The cable conductor core is formed by multiple strands of metal wire twisted together, with an insulation layer, filler structure, and sheath sequentially arranged on the outside. When the cable bends within its permissible bending radius, each structural layer experiences recoverable tension and compression. When the bend is concentrated within a shorter axial length, the tensile strain of the conductor and sheath on the outside of the bend, as well as the compressive deformation on the inside of the bend, increases with increasing curvature. Repeated alternating strain at the same location during cyclic bending can easily lead to conductor fatigue, insulation cracking, or sheath creases; therefore, it is necessary to control the minimum bending radius in high-risk sections.

[0003] Chinese utility model patent CN215342108U discloses a wear-resistant and easily bendable cable. It features a wear-resistant sleeve fitted onto the outside of the cable shell, with adjacent sleeves connected by a movable chamber, a fixed cylinder, a locking block, and a compression spring, enabling small-angle deflection between the sleeves. The patent also includes a first buffer block, a second buffer block, filler, and an elastic rod inside the cable shell to provide springback after bending. This structure buffers bending deformation between the wear-resistant sleeves and inside the cable shell.

[0004] Chinese utility model patent CN212137236U discloses a submarine cable bending limiter, which is formed by symmetrically joined half-tubes. Each half-tube includes a first half-tube and a second half-tube, which are coaxially arranged and have different inner diameters, forming a bending space between them. The limiter is provided with a positioning pin and a positioning hole at its end to connect multiple limiter segments. Each limiter segment limits the bending range of the cable through its internal bending space.

[0005] The aforementioned structures constrain cable bending through elastic connectors, internal elastic supports, or rigid space-limiting mechanisms. Low-voltage power cables that frequently change direction need to retain the small-angle bends required for installation and operation, while also limiting further increases in curvature when the bending radius approaches the lower allowable limit. When the outer sheath stiffness is high, the deformation resistance required during cable installation increases, potentially affecting the cable's adaptability to changing direction. When adjacent rigid sections are limited only by end-face contact, the bending deformation before contact may be concentrated in one section. When only flexible cables are used to limit the distance on the outer bending side, the tension of the flexible cable, the compression distance on the inner side of the bend, and the sway range of the movable connection need to be matched; otherwise, the limiting parts cannot be sequentially stressed within the set bending angle. Summary of the Invention

[0006] This invention provides a breakage-resistant low-voltage power cable to solve the problems in the prior art where an excessively small bending radius of the cable leads to conductor fatigue fracture, insulation layer cracking, and sheath creases.

[0007] To solve the above-mentioned technical problems, the present invention provides a breakage-resistant low-voltage power cable, comprising a cable body, with multiple fixed connection nodes spaced axially around the outer periphery of the cable body. Each fixed connection node is fixed to the cable body and has at least one movable ring capable of deflecting relative to the fixed connection node. The movable ring is connected to the fixed connection node through an elastic connector, allowing it to deflect relative to the fixed connection node when subjected to external force and to reset after the external force is released. When the movable ring reaches its limit deflection position, it abuts against the fixed connection node to limit further deflection. A bending-limiting section is formed between two adjacent fixed connection nodes. Two movable rings located at opposite ends of the same bending-limiting section are connected by multiple connecting cables spaced circumferentially. Each adjacent fixed connection node also has a stop portion facing the bending-limiting section. The connecting cables are used to tension the outer side of the bending-limiting section and limit the outer distance between the two movable rings, while the stop portions abut against each other on the inner side of the bending-limiting section and limit the inner distance between the two fixed connection nodes.

[0008] When the first and second mating rings are screwed together, the clamping part, along with the axial feed of the threaded pair, pushes the circumferentially distributed pressure plates radially inward. The pressure plates clamp the cable body and keep the fixed connection node in the set axial position. When the cable bends within the allowable angle, the connecting cable has not yet reached its effective load-bearing length. The movable ring can tilt relative to the mating ring using the swing gap, and the elastic connector generates different compression amounts as the movable ring tilts. After the bending angle increases, the connecting cable on the outer bend side is tensioned first, limiting the distance between the outer sides of adjacent movable rings from continuing to increase, while simultaneously pulling the movable ring to continue to swing. The remaining swing of the movable ring allows the stop on the inner bend side to continue to approach. When the set angle range is reached, the stop on the inner bend side abuts, the swing limiting surface abuts, and the connecting cable on the outer bend side remains tensioned, respectively limiting the inner distance of adjacent nodes, the swing angle of the movable ring, and the outer distance of adjacent movable rings from continuing to change. After the included angle of a limited bending section is restricted, adjacent sections can still bend using the connecting cable stroke and the swing of the movable ring, so that the total rotation angle of the cable is distributed across multiple axial sections.

[0009] Furthermore, the fixed connection node includes a first connector and a second connector; the first connector includes a first mating ring, and the second connector includes a second mating ring; the movable ring includes a first movable ring sleeved on the outer periphery of the first mating ring and a second movable ring sleeved on the outer periphery of the second mating ring; the first mating ring and the second mating ring are threadedly engaged, the first mating ring is provided with a plurality of pressure plates along the circumferential direction, and the second mating ring is provided with a pressing part, which pushes the pressure plates to retract radially inward as the first mating ring and the second mating ring are engaged.

[0010] Furthermore, the first connecting member also includes a first limiting ring fixed to the first docking ring, and the second connecting member also includes a second limiting ring fixed to the second docking ring; the first limiting ring is used to limit the axial installation position of the first movable ring, and the second limiting ring is used to limit the axial installation position of the second movable ring, and respectively form a space between them and the corresponding movable ring that allows the movable ring to swing; the first movable ring and the second movable ring are respectively clearance-fitted with the corresponding docking ring, and respectively have an axial distance between them and the corresponding limiting ring that allows the movable ring to swing.

[0011] Furthermore, multiple elastic connectors are provided circumferentially between the movable ring and the corresponding limiting ring; the elastic connectors include a screw, a spring and a nut, one end of the screw is connected to the limiting ring, the other end passes through the movable ring in a clearance fit and is connected to the nut, and the spring is sleeved on the screw and abuts between the limiting ring and the movable ring.

[0012] Furthermore, each bend-limiting section has at least four connecting cables, which are evenly distributed along the circumference of the movable ring; two opposing movable rings are respectively provided with anchor seats at the same circumferential position, and the two ends of the same connecting cable are respectively fixedly connected to the corresponding anchor seats.

[0013] Furthermore, the effective length of the connecting cable is set to be tensioned before the opposing stops come into contact with each other, and the swing range of the movable ring relative to the fixed connecting node is set to allow the movable ring to continue to swing in the direction of the force on the connecting cable after the connecting cable is tensioned.

[0014] Furthermore, the inner edge of the movable ring and the outer periphery of the corresponding mating ring are provided with mutually cooperating swing limiting surfaces, which abut against each other when the movable ring reaches the extreme swing position.

[0015] Furthermore, the stop portion is formed by the corresponding mating ring protruding axially towards the bending limit section, and the end of the stop portion is set as an arc abutment surface, with the arc abutment surfaces on adjacent fixed connection nodes facing each other.

[0016] Furthermore, the end of the first mating ring is provided with multiple axial partition grooves along the circumferential direction, and a pressure plate is formed between adjacent axial partition grooves; a pressure guiding slope that cooperates with the pressing part is provided on the side of the pressure plate away from the cable body, and an arc-shaped clamping surface is provided on the side of the pressure plate facing the cable body.

[0017] Furthermore, the connecting cable is a high-strength fiber cable or a flexible metal cable, and the flexible metal cable is provided with an insulating sheath on the outside.

[0018] Beneficial effects: When the fixed connection node is subjected to the tension of the connecting cable, the movable ring deflects relative to the mating ring. The compression of the elastic connector changes with the direction of deflection, and the movable ring still retains a certain deflection stroke after the connecting cable is tensioned. After the stop and the deflection limiting surface come into contact, the included angle of the bending limit section is restricted.

[0019] Multiple fixed connection nodes are spaced apart along the axial direction of the cable body, forming bending-limiting sections between adjacent nodes. Once a bending-limiting section reaches a set angle, external directional displacement causes adjacent bending-limiting sections that have not reached the set angle to continue bending, resulting in cable bending deformation distributed across multiple sections. The axial spacing of each section, the effective length of the connecting cable, the protrusion of the stop, and the sway clearance are set according to the corresponding allowable bending angle. Attached Figure Description

[0020] Figure 1 A schematic diagram of the overall structure with multiple fixed connection nodes on the outer periphery of the cable body.

[0021] Figure 2 This is an isometric structural diagram of a fixed connection node and connecting cable.

[0022] Figure 3 A schematic diagram of the isometric structure from another perspective of the fixed connection node.

[0023] Figure 4 This is a schematic diagram of the axial cross-sectional structure of the first and second docking rings, with part A shown in the figure.

[0024] Figure 5 for Figure 4 A magnified structural diagram of point A in the middle.

[0025] Figure 6 This is a schematic diagram of the structure of adjacent fixed connection nodes and connecting cables when the main body of the cable is bent.

[0026] Reference numerals: 1. Cable body; 2. Fixed connection node; 21. First connector; 211. First mating ring; 212. First movable ring; 213. First limiting ring; 2131. Swing limiting surface; 214. Pressure plate; 2141. Pressure guiding slope; 22. Second connector; 221. Second mating ring; 2211. Pressing part; 222. Second movable ring; 223. Second limiting ring; 23. Elastic connector; 231. Screw; 232. Spring; 233. Nut; 24. Anchor seat; 25. Stop part; 3. Connecting cable. Detailed Implementation

[0027] like Figures 1-6As shown, a breakage-resistant low-voltage power cable includes a cable body 1 and multiple fixed connection nodes 2 disposed on the outer periphery of the cable body 1. The multiple fixed connection nodes 2 are arranged at intervals along the axial direction of the cable body 1, and a bending-limiting section is formed between two adjacent fixed connection nodes 2. A connecting cable 3 is disposed on the outer periphery of the bending-limiting section.

[0028] The cable body 1 includes conductor cores, insulation layer, filler layer, and sheath. The conductor cores are multi-strand stranded metal conductors, each covered by an insulation layer. Multiple insulated conductor cores are stranded together to form the cable core. The filler layer fills the gaps around the cable core, maintaining its round shape. The sheath continuously covers the outside of the filler layer. Fixed connection nodes 2 are clamped onto the outer surface of the sheath, without altering the electrical connection between the conductor cores and the insulation layer.

[0029] The fixed connection node 2 includes a first connector 21 and a second connector 22. The first connector 21 and the second connector 22 are arranged opposite each other along the axial direction of the cable body 1, and are formed integrally by screwing them together. The clamping force generated by the screwing positions the fixed connection node 2 at a predetermined axial position on the cable body 1. Adjacent fixed connection nodes 2 are not directly connected by threads, and their opposing sides retain the axial spacing required for the bending limit section. The fixed connection node 2 is formed by screwing together the first connector 21 and the second connector 22, and two adjacent fixed connection nodes 2 together define the bending limit section between them.

[0030] The first connector 21 includes a first mating ring 211, a first movable ring 212, and a first limiting ring 213. The first mating ring 211 is sleeved on the outer periphery of the cable body 1, the first movable ring 212 is sleeved on the outer periphery of the first mating ring 211, and the first limiting ring 213 is fixedly connected to the side of the first mating ring 211 near the bending limit section. The end of the first mating ring 211 away from the bending limit section has an annular wall that maintains circumferential rigidity, and an external thread section is disposed on the outer periphery of this rigid annular wall. The first limiting ring 213 is fixedly connected to the first mating ring 211, and the first movable ring 212 is located at the installation position defined by the first limiting ring 213 and the first mating ring 211.

[0031] The second connector 22 includes a second mating ring 221, a second movable ring 222, and a second limiting ring 223. The second mating ring 221 is sleeved on the outer periphery of the cable body 1, the second movable ring 222 is sleeved on the outer periphery of the second mating ring 221, and the second limiting ring 223 is fixedly connected to the side of the second mating ring 221 near the adjacent bending section. The second mating ring 221 is provided with an internal thread section that mates with the external thread section of the first mating ring 211, and a clamping part 2211 is provided on the inner side of the second mating ring 221. After the first mating ring 211 and the second mating ring 221 are screwed together, the first limiting ring 213 and the second limiting ring 223 are located on both axial sides of the fixed connection node 2, and the first movable ring 212 and the second movable ring 222 face the adjacent bending sections on both sides.

[0032] The pressure plate 214 extends axially from the external threaded end of the first mating ring 211, and the portion where the pressure plate 214 is located is a threadless section. This threadless section has multiple axially spaced grooves along its circumference, with a pressure plate 214 formed between every two adjacent axially spaced grooves. The root of the pressure plate 214 is continuously connected to the rigid annular wall of the first mating ring 211, and its free end extends towards the direction of the second mating ring 221. The axially spaced grooves provide circumferential space for the pressure plate 214 to undergo elastic deformation radially inward towards the cable body 1. The inner surfaces of each pressure plate 214 together form a clamping hole adapted to the outer circumference of the sheath; when the pressure plate 214 retracts radially, the diameter of the external threaded section and its engagement with the internal threaded section remain unchanged.

[0033] A pressure-guiding slope 2141 is provided on the unthreaded outer area of ​​the pressure plate 214. The pressure-guiding slope 2141 gradually slopes outward along the screwing direction of the first mating ring 211 and the second mating ring 221. When the external thread section of the first mating ring 211 is screwed into the second mating ring 221, the second mating ring 221 is axially fed relative to the first mating ring 211. The clamping part 2211 moves along the pressure-guiding slope 2141 and applies a radial component force toward the cable body 1 to each pressure plate 214. Each pressure plate 214 synchronously retracts inward, and the axial feed is converted into a circumferentially distributed radial clamping amount.

[0034] The material and root thickness of the pressure plate 214 are determined according to the required radial deformation, so that the pressure plate 214 maintains elastic deformation within the clamping range. When the first mating ring 211 and the second mating ring 221 are loosened in opposite directions, the clamping part 2211 exits the pressure guide slope 2141, and each pressure plate 214 recovers outward by its own elasticity, and the diameter of the clamping hole increases.

[0035] Each pressure plate 214 has an arc-shaped clamping surface on the side facing the sheath, the curvature of which matches the curvature of the outer surface of the sheath. Multiple arc-shaped clamping surfaces are arranged circumferentially around the outside of the sheath. As the engagement depth of the first mating ring 211 and the second mating ring 221 increases, the arc-shaped clamping surfaces of each pressure plate 214 simultaneously approach the sheath and apply clamping force to the sheath at multiple circumferential positions.

[0036] The inner diameter of the first movable ring 212 is larger than the outer diameter of the corresponding mounting section of the first mating ring 211, forming an annular sway gap between them. The first movable ring 212 is located on the side of the first limiting ring 213 away from the middle of the fixed connection node 2, and an axial gap is maintained between the first movable ring 212 and the first limiting ring 213. When the first movable ring 212 is subjected to the eccentric tension of the connecting cable 3, the first movable ring 212 tilts relative to the first mating ring 211 using the radial gap and the axial gap.

[0037] The second movable ring 222 and the second mating ring 221 adopt the same swaying installation relationship. The inner hole of the second movable ring 222 is clearance-fitted with the outer circumference of the second mating ring 221. The second movable ring 222 is located on the side of the second limiting ring 223 away from the middle of the fixed connection node 2. When the second movable ring 222 sways until the edge of its inner hole contacts the outer circumference of the second mating ring 221, it forms a swaying limiting state; after the corresponding limiting structure abuts, the tilt angle of the second movable ring 222 in this direction no longer increases. The first movable ring 212 and the first mating ring 211 adopt the same swaying limiting relationship.

[0038] Multiple elastic connectors 23 are provided between the first movable ring 212 and the first limiting ring 213, and between the second movable ring 222 and the second limiting ring 223. The multiple elastic connectors 23 are evenly arranged along the circumference of the corresponding movable ring, so that the movable ring is constrained in all radial directions. Each elastic connector 23 includes a screw 231, a spring 232, and a nut 233. One end of the screw 231 is connected to the corresponding limiting ring, and the other end of the screw 231 passes through a through hole on the movable ring and is connected to the nut 233.

[0039] The diameter of the through hole on the movable ring is larger than the outer diameter of the portion of the screw 231 that passes through the through hole, and the gap between the two is adapted to the limit deflection angle of the movable ring. A spring 232 is sleeved on the outer circumference of the screw 231 and abuts against the limiting ring and the movable ring. A nut 233 restricts the movable ring from retracting from the screw 231 from the side of the movable ring away from the limiting ring. When the movable ring deflects in a certain direction, the compression of the springs 232 at different circumferential positions varies; each spring 232 acts as a compression spring, and the difference in compression generates a restoring torque opposite to the deflection direction.

[0040] The axial position of nut 233 on screw 231 is used to set the initial compression of spring 232. When multiple nuts 233 are adjusted to the same reference position, the movable ring is close to the center position when the cable body 1 is not subjected to lateral load. When the initial return force of the movable ring is changed, each nut 233 is adjusted equally along screw 231 so that each spring 232 maintains the same initial compression.

[0041] Multiple connecting cables 3 are arranged between the opposing movable rings in two adjacent fixed connection nodes 2. The second movable ring 222 located in the preceding fixed connection node 2 and the first movable ring 212 located in the following fixed connection node 2 are arranged facing each other. One end of the connecting cable 3 is connected to the second movable ring 222, and the other end is connected to the first movable ring 212. This connection allows the connecting cable 3 to cross the bending limit section without connecting two connectors that are already threaded together within the same fixed connection node 2.

[0042] Anchor seats 24 are provided on both the first movable ring 212 and the second movable ring 222, and the anchor seats 24 are evenly distributed along the circumference of the movable rings. The anchor seats 24 on the two opposing movable rings correspond one-to-one in the circumferential position, and the two ends of the same connecting cable 3 are respectively fixedly connected to a set of corresponding anchor seats 24. When the cable body 1 is in a straight state, the connecting cable 3 extends axially along the bending limit section.

[0043] Four connecting cables 3 are installed in each bending-limited section, and the four connecting cables 3 are arranged at the same central angle intervals along the circumference of the movable ring. The connecting cables 3 are flexible cables capable of withstanding tension and allowing bending, and their working length is the effective load-bearing length between two fixed connection positions. When the number of connecting cables 3 increases, each connecting cable 3 is still evenly distributed along the circumference of the movable ring.

[0044] Stops 25 are provided on the mating rings of adjacent fixed connection nodes 2 facing the bending limit section. The stops 25 protrude from the axial end of the corresponding mating ring toward the bending limit section, and the stops 25 at both ends of the same bending limit section face each other. The ends of the stops 25 form arc abutment surfaces, and when the bending limit section bends, the two arc abutment surfaces on the inner bend side move closer to each other.

[0045] The first and second mating rings 211 and 221 are provided with arc-shaped transition portions at the axial edge of the bending-limited section, and the connection position between the stop portion 25 and the main body of the mating ring is also arc-shaped. A radial gap is maintained between the arc-shaped transition portion and the sheath, so that the cable body 1 does not contact the sharp edge of the mating ring when bending within the allowable angle. After the stop portion 25 enters the contact area, the load is transferred to the clamping area of ​​the sheath through the mating ring and the pressure plate 214.

[0046] The limiting bending angle of the bend-limited section is determined by the axial spacing of the fixed connection nodes 2, the axial protrusion and effective contact radius of the stop part 25, the effective length of the connecting cable 3, the sway clearance between the movable ring and the mating ring, and the position of the sway limiting surface. During the design process, the target minimum bending radius is first determined based on the outer diameter of the cable body 1, the structural layer material, and manufacturing requirements. Then, the allowable center angle of a single bend-limited section is determined based on the target minimum bending radius, and the aforementioned geometric quantities are then configured. The sum of the center angles of multiple bend-limited sections constitutes the total allowable turning angle of the protected area.

[0047] The effective length of the connecting cable 3 is set such that the connecting cable 3 on the outer curved side changes from a low-tension state to a taut state before contacting the stop 25. After the connecting cable 3 is taut, its tension acts on the anchor seat 24 and pulls the movable ring to sway. The sway gap between the movable ring and the docking ring retains a certain swaying stroke, so the tensioning of the connecting cable 3 will not immediately rigidly lock the two fixed connection nodes 2. During this continued swaying stroke, the movable ring compresses the springs 232 at different circumferential positions, so that the limiting stiffness gradually increases.

[0048] The position of the stop part 25 is set such that when the movable ring approaches the limit deflection position, the two stop parts 25 on the inner side of the bend in the same limiting bending section enter contact. After the movable ring reaches the limit deflection position, the edge of the inner hole of the movable ring abuts against the deflection limiting surface 2131 on the outer periphery of the corresponding mating ring. The connecting cable 3 first enters the tension transmission, and the movable ring then continues to deflect under the constraint of the elastic connector 23. The stop part 25 and the deflection limiting surface 2131 enter the bearing range in the limit angle range.

[0049] The limit bending angle allows for a small trigger difference due to manufacturing tolerances and spring compression. By selecting a connecting cable 3 of appropriate effective length and a stop 25 with appropriate protrusion, and adjusting the position of the nut 233 to set the initial compression of the spring 232, the stop 25 and the sway limiting surface 2131 enter contact while the connecting cable 3 maintains tension. The connecting cable 3, the stop 25, and the sway limiting surface 2131 are each stressed before the cable body 1 reaches the minimum permissible bending radius.

[0050] The clamping force of the clamping plate 214 at the fixed connection node 2 is set according to the design tension of the connecting cable 3 under extreme bending conditions. When the number of clamping plates 214 increases, the radial load borne by a single clamping plate 214 decreases accordingly. The screw-in depth is used to adjust the inward amount of the clamping plate 214. During assembly, the verification condition is that the fixed connection node 2 does not slip axially under the design tension of the connecting cable and the sheath does not produce irreversible indentations.

[0051] After the first mating ring 211 and the second mating ring 221 are screwed into the set position, the axial slippage of the fixed connection node 2 relative to the sheath is measured. If the axial slippage does not meet the design requirements, the screwing depth of the first mating ring 211 and the second mating ring 221 is adjusted; if irreversible indentations appear on the sheath, the screwing depth is reduced. The same verification conditions are used for each fixed connection node 2.

[0052] The fixed connection node 2 is assembled before the cable termination. During assembly, the first connector 21 and the second connector 22 are sequentially fitted onto the outer periphery of the cable body 1 according to the number of fixed connection nodes 2. After determining the position of each node, the first mating ring 211 and the second mating ring 221 in each node are screwed together so that the pressure plate 214 clamps the sheath. After each node is clamped, the connecting cables 3 are installed one by one between the anchor seats 24 of the opposing movable rings of adjacent nodes.

[0053] Before installing the connecting cable 3, ensure that the axes of adjacent fixed connection nodes 2 coincide and measure the axial distance between opposing anchor seats 24. Both ends of the connecting cable 3 are fixedly connected to the corresponding anchor seats 24. After installation, the connecting cable 3 maintains a low-tension stroke when the cable body 1 is in a straight state.

[0054] When the fixed connection node 2 is not subjected to lateral load, each movable ring approaches the center position under the action of the circumferential spring 232, and the wobble gap between the movable ring and the mating ring is evenly distributed in each circumferential position. The connecting cable 3 retains a low tension stroke corresponding to the allowable bending angle, and the stop portions 25 maintain an axial spacing. The pressure plate 214 continuously clamps the sheath, so that the position of the fixed connection node 2 does not change with the small wobble of the movable ring.

[0055] When the cable body 1 undergoes a normal slight bend, the axes of adjacent fixed connection nodes 2 form a small angle, the node spacing on the inner bend side decreases, and the node spacing on the outer bend side increases. The low-tension stroke of the connecting cable 3 on the outer bend side gradually decreases, and the movable ring produces a small-angle sway under the slight traction of the connecting cable 3 and the elastic constraint of the spring 232.

[0056] As the bending angle continues to increase, the connecting cable 3 on the outer side of the bend reaches its effective bearing length and forms tension. The connecting cable 3 limits the distance between the outer anchor seats 24 of the adjacent movable ring within its effective length range, while transferring the tension to the movable ring. The movable ring continues to deflect relative to the docking ring, and the compression of the spring 232 at different circumferential positions varies, while the fixed connection node 2 still maintains its clamping of the sheath.

[0057] When the bending section reaches the limit bending angle range, the opposing stop 25 on the inner bending side contacts and restricts the inner distance between the two fixed connection nodes 2 from continuing to shorten, the swing limiting surface of the movable ring abuts and restricts the swing angle at the node from continuing to increase, and the connecting cable 3 on the outer bending side remains taut and restricts the outer distance between the two movable rings from continuing to increase.

[0058] Once a certain bend-limited section reaches its ultimate bearing capacity, the angle between the nodes at both ends of that section is restricted from increasing. When external steering displacement continues to be applied, adjacent bend-limited sections that have not yet reached their ultimate angle continue to experience swaying of the moving ring and changes in the travel of the connecting cables.

[0059] When the bending force decreases, the elastic recovery of the cable body 1 reduces the included angle between adjacent fixed connection nodes 2 and gradually separates the already contacting stop 25. The tension of the connecting cable 3 decreases as the distance to the outer anchor seat 24 decreases, and the compressed spring 232 pushes the movable ring to swing back towards the center position, releasing the abutment from the sway limit surface. The spring 232 is responsible for the return of the movable ring. The separation between the fixed connection nodes 2 and the overall straightening of the cable are mainly achieved by the elastic recovery of the cable body 1 and the change in the direction of external movement.

[0060] When the bending direction is between two adjacent connecting cables 3, the two connecting cables 3 respectively bear the tensile component of the outer bending area and jointly pull the movable ring to deflect in that direction. The circumferentially uniformly arranged elastic connectors 23 apply a restoring force to the movable ring in the opposite direction of deflection, and the arc-shaped contact surfaces on the inner bending side contact at opposite circumferential positions. When the cable body 1 bends around its axis in different directions, the connecting cables 3, elastic connectors 23, and stop portions 25 at corresponding circumferential positions participate in bearing the force.

[0061] The ring of fixed connection node 2 is made of insulating material or surface-insulated material with sufficient compressive strength and wear resistance. The connecting cable 3 is made of high-strength fiber cable or flexible metal cable with an insulating sheath. The spring 232 is made of fatigue-resistant elastic material. The selection of materials is based on the temperature, humidity, oil contamination, and electrical insulation requirements of the operating environment. All conductive material parts are kept insulated from the conductor core.

[0062] Fixed connection nodes 2 are arranged at the equipment inlet, the repeatedly bending section of the mobile power supply cable, or the cable turning transition section. The installation range covers the predetermined concentrated bending position, and bending limit sections are set on both sides of the position. The number of fixed connection nodes 2 is determined according to the protection length and the target total turning angle. The effective length of the connecting cable 3, the protrusion of the stop part 25, and the sway clearance of each bending limit section are set according to the corresponding target bending angle.

[0063] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A break-resistant low-voltage power cable, comprising a cable body, characterized in that: Multiple fixed connection nodes are spaced axially around the outer periphery of the cable body. Each fixed connection node is fixed to the cable body and has at least one movable ring that can deflect relative to the fixed connection node. The movable ring is connected to the fixed connection node through an elastic connector, allowing it to deflect relative to the fixed connection node when subjected to external force and to return to its original position after the external force is released. When the movable ring reaches its limit deflection position, it abuts against the fixed connection node to limit further deflection. A bending limit section is formed between two adjacent fixed connection nodes. Two movable rings located at opposite ends of the same bending limit section are connected by multiple connecting cables spaced circumferentially. Each adjacent fixed connection node also has a stop portion facing the bending limit section. The connecting cables are used to tension the outer side of the bending limit section and limit the outer distance between the two movable rings. The stop portions abut against each other on the inner side of the bending limit section and limit the inner distance between the two fixed connection nodes.

2. The breakage-resistant low-voltage power cable according to claim 1, characterized in that, The fixed connection node includes a first connector and a second connector; the first connector includes a first mating ring, and the second connector includes a second mating ring; the movable ring includes a first movable ring sleeved on the outer periphery of the first mating ring and a second movable ring sleeved on the outer periphery of the second mating ring; the first mating ring and the second mating ring are screwed together, the first mating ring is provided with a plurality of pressure plates along the circumferential direction, and the second mating ring is provided with a pressing part, which pushes the pressure plates to retract radially inward as the first mating ring and the second mating ring are screwed together.

3. The breakage-resistant low-voltage power cable according to claim 2, characterized in that, The first connector further includes a first limiting ring fixed to the first docking ring, and the second connector further includes a second limiting ring fixed to the second docking ring; the first limiting ring is used to limit the axial installation position of the first movable ring, and the second limiting ring is used to limit the axial installation position of the second movable ring, and respectively form a space between them that allows the movable ring to deflect; the first movable ring and the second movable ring are respectively clearance-fitted with the corresponding docking ring, and respectively have an axial distance between them and the corresponding limiting ring that allows the movable ring to deflect.

4. The breakage-resistant low-voltage power cable according to claim 3, characterized in that, The first and second movable rings are respectively provided with multiple elastic connecting members along the circumferential direction between them and the corresponding limiting rings; the elastic connecting members include a screw, a spring and a nut, one end of the screw is connected to the limiting ring, the other end passes through the movable ring in a clearance fit and is connected to the nut, and the spring is sleeved on the screw and abuts between the limiting ring and the movable ring.

5. The breakage-resistant low-voltage power cable according to claim 1, characterized in that, Each bend-limiting section has at least four connecting cables, which are evenly distributed along the circumference of the movable ring. Two opposing movable rings are respectively provided with anchor seats at the same circumferential position, and the two ends of the same connecting cable are respectively fixedly connected to the corresponding anchor seats.

6. The breakage-resistant low-voltage power cable according to claim 5, characterized in that, The effective length of the connecting cable is set to be tensioned before the opposing stops abut against each other, and the swing range of the movable ring relative to the fixed connecting node is set to allow the movable ring to continue to swing in the direction of the force on the connecting cable after the connecting cable is tensioned.

7. The breakage-resistant low-voltage power cable according to claim 3, characterized in that, The inner edge of the movable ring and the outer periphery of the corresponding mating ring are provided with mutually cooperating swing limiting surfaces, which abut against each other when the movable ring reaches the extreme swing position.

8. The breakage-resistant low-voltage power cable according to claim 2, characterized in that, The stop portion is formed by the corresponding mating ring protruding axially towards the bending limit section, and the end of the stop portion is set as an arc abutment surface, with the arc abutment surfaces on adjacent fixed connection nodes facing each other.

9. The breakage-resistant low-voltage power cable according to claim 2, characterized in that, The first docking ring has multiple axial partition grooves circumferentially opened at its end, and the pressure plate is formed between adjacent axial partition grooves; the side of the pressure plate away from the cable body is provided with a pressure guiding slope that cooperates with the pressing part, and the side of the pressure plate facing the cable body is provided with an arc-shaped clamping surface.

10. The breakage-resistant low-voltage power cable according to claim 1, characterized in that, The connecting cable is a high-strength fiber cable or a flexible metal cable, and the flexible metal cable has an insulating sheath on the outside.

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