A bending-resistant medium-voltage power cable

Abstract

The present invention relates to the technical field of power cables, and specifically to a bending-resistant medium-voltage power cable, wherein a plurality of cable cores are installed at equal angles inside the outer sheath along the circumferential direction, a plurality of support pads are evenly and equidistantly installed inside the outer sheath, a protective tube is installed in the middle of the side end face of the support pad, a plurality of convex plates are installed at equal angles along the circumferential direction on the edge of the side end face of the support pad, and a plurality of concave plates are evenly and equidistantly installed on the side end face of the convex plate. The present invention can achieve equal unloading of external bending stress and external impact pressure, and realize internal and external double pressure relief, so that the stress borne by various parts of the cable is more balanced, and can dynamically adjust the minimum bending radius of the cable, so as to realize comprehensive adjustment of the bending toughness and bending flexibility of the cable, effectively take into account the needs of different usage scenarios, and improve the application flexibility of the cable while improving the effective utilization rate of the internal load pressure of the cable, thereby increasing the effective service life of the cable.

Description

Technical Field

[0001] The invention relates to the technical field of power cables, in particular to a bending-resistant medium-voltage power cable. Background Art

[0002] ‌Bending-resistant medium-voltage power cables are an important component of the power system. They have excellent bending resistance and moderate voltage levels. They are widely used in industrial automation systems, construction sites, water conservancy and power engineering, shipbuilding and marine engineering, etc., providing stable power support for equipment in these fields. At the same time, due to their flexibility and durability, they are particularly suitable for powering mobile equipment, such as electric forklifts, cranes, etc.;

[0003] However, current cables usually adjust the bending resistance and compression resistance of the cables by adjusting the thickness of the outer sheath of the cable core. This fails to effectively take into account both the bending resistance and compression resistance of the cables. In addition, the minimum bending radius of the cables is not controlled, and the bending toughness and bending flexibility of the cables cannot be flexibly adjusted. The mechanical properties of the cables cannot be fully utilized during use, and it is difficult to flexibly take into account the needs of different scenarios. This not only narrows the application scope of the cables, but also reduces the effective service life of the cables, making the use of the cables unsafe and unreliable. Summary of the invention

[0004] The present invention provides a bending-resistant medium-voltage power cable, which can effectively solve the problem that the current cables proposed in the above background technology usually adjust the bending resistance and compression resistance of the cables by adjusting the thickness of the outer sheath of the cable core, and cannot effectively take into account the bending resistance and compression resistance of the cables. The minimum bending radius of the cable is not controlled, and the bending toughness and bending flexibility of the cable cannot be flexibly adjusted. During use, the mechanical properties of the cable cannot be fully utilized, and it is difficult to flexibly take into account the requirements of different scenarios, which not only narrows the application scope of the cable, but also reduces the effective service life of the cable, resulting in unsafe and unreliable use of the cable.

[0005] To achieve the above object, the present invention provides the following technical solution: a bending-resistant medium-voltage power cable, comprising an outer sheath, a plurality of cable cores are installed at equal angles in the circumferential direction inside the outer sheath, and an active bending-resistant mechanism is installed inside the outer sheath at a position outside the cable core;

[0006] The active bending resistance mechanism includes a support pad;

[0007] A number of support pads are evenly and equidistantly installed inside the outer sheath, a protective tube is installed in the middle of the side end surface of the support pad, a number of convex plates are installed at equal angles along the circumferential direction on the edge of the side end surface of the support pad, a number of concave plates are evenly and equidistantly installed on the side end surface of the convex plate, a guide head is installed at the end of the protective tube, a number of connecting tubes are installed at equal angles along the circumferential direction on the outer curved surface of the guide head, an airbag block is installed at the end of the connecting tube, both side end surfaces of the airbag block are clamped with elastic clamps, a delivery tube is installed on the outer curved surface of the airbag block, a ring box is installed at the end of the delivery tube, and a number of inclined tubes are installed at equal angles along the circumferential direction on the side end surface of the ring box;

[0008] A piston is symmetrically and slidably installed inside the support pad, a spherical plug is rollingly installed inside the protective tube, a number of clamping ears are evenly and equidistantly installed at the corners of the outer curved surfaces of the support pad and the convex plate, and reinforcing ribs are embedded and installed at the ends of the clamping ears. A clamping tube is installed on the outer curved surface of the airbag block, and a number of balls are rollingly installed at equal angles along the circumferential direction at the inner curved surface of the elastic clamp corresponding to the position of the cable core, and a clamping sleeve is sleeved on the outer side of the cable core;

[0009] An air valve is embedded and installed on one side of the outer curved surface of the ring box, a plurality of cables are installed at equal angles along the circumferential direction on the edge of the side end face of the guide head located outside the protective tube, a ring plate is rotatably installed inside the guide head, an arc plate is installed on the edge of the side end face of the ring plate, and a sealing ring is installed on the side end face of the arc plate.

[0010] Preferably, the outer curved surface of the cable core is covered with an insulating sleeve, a shielding sleeve is embedded and installed on the outer side of the insulating sleeve at the inner side of the ferrule, a track groove is provided on the outer curved surface of the ferrule at the position corresponding to the ball, and the concave plate and the ball are both in line with the ferrule.

[0011] Preferably, the inclined tube is axially inclined relative to the cable core, and both ends of the inclined tube are connected to the inner cavities of two adjacent ring boxes, the inner cavity of the airbag block is connected to the inner cavity of the ring box through the conveying tube, and the inner cavities of two adjacent airbag blocks are connected through the clamping tube.

[0012] Preferably, the inner cavity of the protective tube is directly connected to the inner cavity of the support pad, annular ribs are symmetrically installed on the inner curved surface of the guide head, and the inner diameter of the annular ribs is smaller than the outer diameter of the spherical plug, the piston fits with the support pad, the spherical plug fits with the protective tube, the interior of the protective tube is filled with helium at a position between the spherical plug and the piston, and the inner cavity of the support pad is filled with helium at a position between the two pistons.

[0013] Preferably, the number of the convex plates is the same as the number of cable cores, the concave plates and the convex plates together form a hollow support structure, and the concave plates and the convex plates are integrally formed, and the concave plates fit with the ferrules.

[0014] Preferably, the sealing ring is rotatably connected to the end surface on the other side of the guide head in a sealing manner, and the width of the arc plate is greater than the diameter of the connecting pipe.

[0015] Preferably, a parallel heat exchange mechanism is installed on the outer side of the protective tube, and the parallel heat exchange mechanism includes a special-shaped frame;

[0016] A special-shaped frame is installed inside the support pad at a position between the two pistons, an inner spacer is installed in the middle of the side end surface of the special-shaped frame, a shaft rod is installed in the middle of the side end surface of the piston, and a movable plug is installed at the end of the shaft rod located inside the inner spacer. A groove is opened in the middle of the outer curved surface of the support pad at a position corresponding to the cable core, a connecting hole is opened at the outer curved surface of the inner spacer at a position corresponding to the groove, and a plurality of striped grooves are opened at equal angles along the circumferential direction on the side end surface of the groove;

[0017] The outer side of the protective tube is filled with a strip bag at the inner side of the convex plate, non-woven fabrics are embedded in the middle of the end faces of both sides of the strip bag, a square tube is installed in the middle of the outer curved surface of the strip bag, the outer side of the airbag block is sleeved with an inner sleeve at the inner side of the ring box, the outer side of the inner sleeve is sleeved with an outer sleeve, and the inner side of the outer sleeve is filled with moisture-proof cotton at the outer side of the inclined tube;

[0018] The outer curved surface of the outer sleeve is located at the inner side of the outer sleeve and is evenly and evenly installed with a number of ring shells. The outer curved surface of the outer sleeve is located at the inner side of the ring shell and is provided with a number of strip openings at equal angles along the circumferential direction. The outer curved surface of the outer sleeve is located at the outer side of the ring shell and is provided with a number of strip ribs at equal angles along the circumferential direction. The side end surface of the ring shell is provided with a number of inlets and outlets at equal angles along the circumferential direction.

[0019] Preferably, the difference between the length of the inner spacer and the inner diameter of the connecting hole is twice the length of the shaft rod, and the length of the shaft rod is the maximum distance between the piston and the special-shaped frame.

[0020] Preferably, the inner cavity of the strip-shaped bag is connected to a chamber enclosed by the square tube and the inner sleeve and the outer sleeve, and the length of the strip-shaped bag is the same as the length of the protective tube.

[0021] Preferably, the chamber enclosed by the inner sleeve and the outer sleeve is connected to the annular shell through a strip opening, the position of the annular shell corresponds to the end of the square tube, the strip ribs and the inlet and outlet are adjacent to each other, and the strip ribs are spiral, and the strip ribs and the outer curved surface of the annular shell are connected to the inner curved surface of the outer sleeve.

[0022] Compared with the prior art, the invention has the following beneficial effects: the invention has a scientific and reasonable structure and is safe and convenient to use;

[0023] 1. An active bending resistance mechanism is provided. Through the cooperation of the support pad, protective tube, guide piston and spherical plug, an elastic limit structure can be formed to obtain sufficient dispersed force unloading space during the use of the cable. In cooperation with the airbag block, clamping tube, ring box and inclined tube, it can achieve equal unloading of external bending stress and external impact pressure, and realize internal and external double pressure relief. While greatly improving the pressure relief threshold, the bending resistance and pressure resistance of the cable are improved simultaneously, and the compatibility of the pressure resistance and bending resistance of the cable is effectively improved. At the same time, the stress carried by each part of the cable can be more balanced, effectively avoiding damage caused by local stress imbalance of the cable, and greatly improving the pressure resistance and effective service life of the cable;

[0024] In conjunction with the gas valve, a helium flow passage can be constructed, the bending performance of the cable can be conveniently adjusted according to actual needs, the minimum bending radius of the cable can be dynamically adjusted, and the comprehensive regulation of the bending toughness and bending flexibility of the cable can be achieved. It effectively takes into account the needs of different usage scenarios and greatly expands the effective application range of the cable. While improving the application flexibility of the cable, it can more fully and stably utilize the bending toughness at the same internal load pressure, effectively avoid the pressure waste of the cable internal load caused by the bending toughness being greater than the demand, improve the effective utilization rate of the cable internal load pressure, and further increase the effective service life of the cable in disguise.

[0025] 2. Through the coordination of the convex plate and the concave plate, a hollow support structure can be constructed. While giving the cable core a stable elastic support force, it can cooperate with the elastic clamp, ball and ferrule to make full use of the internal air pressure of the protective tube, inclined tube and airbag block to dynamically limit and fix the cable core. While improving the density inside the cable and greatly enhancing the bending resistance of the cable, it can effectively improve the fullness of the cable's appearance, fully maintain the stability of the cable's mechanical properties, improve the cable's anti-interference ability, and effectively avoid the cable core dislocation of the cable;

[0026] The hollow design can reduce material loss and make the cable lighter. At the same time, the fluidity of helium can be used to promote internal circulation heat exchange in the cable, improve the internal heat balance of the cable, and achieve gas insulation equivalently. The insulation performance of the cable can be superimposed and compensated, which can fully improve the reliability of the insulation performance of the cable. Through the coordination of the ears, reinforcing ribs and ropes, the bending resistance of the cable can be further limited while the tensile strength of the cable is improved, thereby improving the bending resistance of the cable. Through the coordination of the ring plate, arc plate and sealing ring, the cable end can be double-sealed to block the flow, which can reduce the impact pressure shared at the cable joint while retaining the pressure relief performance of the cable end, thereby greatly improving the stability of the cable joint.

[0027] 3. A parallel heat exchange mechanism is provided. The special-shaped frame, inner spacer, shaft rod and movable plug cooperate with each other to construct a synchronous conversion structure. The internal supporting air pressure of the cable can be fully utilized to transform the external impact pressure and bending stress into driving force, promote the heat exchange between the inside and outside of the cable, and transform the passive heat dissipation into active heat exchange. The internal and external heat exchange capacity of the cable can be effectively enhanced, and the temperature inside the cable can be more balanced and stable, so that the cable can work more efficiently, continuously and stably, and improve the safety of the cable. At the same time, the heat dissipated during the working process of the cable can be used to maintain the temperature stability of the cable skin, effectively adapt to the influence of different ambient temperatures on the bending performance of the cable, and effectively ensure the integrity and reliability of the mechanical properties of the cable;

[0028] Cooperating with grooves, connecting holes, striped grooves, square tubes, inner sleeves, outer sleeves, ring shells, strip mouths, strip ribs and inlets and outlets, the internal and external heat exchange airflows can be diverted and guided, making the heat exchange of the cable more uniform and improving the comprehensiveness of the heat exchange of the cable. At the same time, it can promote the heat exchange at the cable joints, make the temperature at the joints more stable, and further improve the working stability of the cable. With the purification and dehumidification function of strip capsules, non-woven fabrics and moisture-proof cotton, it can make full use of the heat dissipated during the operation of the cable to improve the dryness inside the cable, and can fully prevent the cable from being eroded by external moisture, thereby improving the safety of the cable.

[0029] To sum up, this cable improves the bending resistance of the cable without affecting the pressure resistance and heat dissipation performance, and the minimum bending radius of the cable can be adjusted, which can effectively meet the different requirements of the bending toughness and bending flexibility of the cable in different usage environments, improve the flexibility of cable use, and can more fully and effectively exert the mechanical properties of the cable, thereby increasing the effective service life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0031] In the attached picture:

[0032] Figure 1 It is a schematic diagram of the structure of the present invention;

[0033] Figure 2 It is a schematic diagram of the cable core installation structure of the present invention;

[0034] Figure 3 It is a schematic diagram of the elastic clamp installation structure of the present invention;

[0035] Figure 4 It is a schematic diagram of the structure of the active bending resistance mechanism of the present invention;

[0036] Figure 5It is a schematic diagram of the support pad installation structure of the present invention;

[0037] Figure 6 It is a schematic diagram of the structure of the parallel heat exchange mechanism of the present invention;

[0038] Figure 7 It is a schematic diagram of the installation structure of the special-shaped frame of the present invention;

[0039] Numbers in the figure: 1, outer sheath; 2, cable core; 3, insulation sleeve; 4, shielding sleeve;

[0040] 200, active bending resistance mechanism; 201, support pad; 202, protective tube; 203, convex plate; 204, concave plate; 205, guide head; 206, connecting tube; 207, air bag block; 208, elastic clamp; 209, conveying tube; 210, ring box; 211, oblique tube; 212, piston; 213, spherical plug; 214, clamp ear; 215, reinforcing rib; 216, clamp tube; 217, ball; 218, clamp sleeve; 219, air valve; 220, cable band; 221, ring plate; 222, arc plate; 223, sealing ring;

[0041] 2051, annular rib; 2181, track groove;

[0042] 300, parallel heat exchange mechanism; 301, special-shaped frame; 302, inner spacer; 303, shaft; 304, movable plug; 305, groove; 306, connecting hole; 307, striped groove; 308, strip capsule; 309, non-woven fabric; 310, square tube; 311, inner sleeve; 312, outer sleeve; 313, moisture-proof cotton; 314, ring shell; 315, strip mouth; 316, strip rib; 317, inlet and outlet. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0044] Example: Figure 1-7 As shown, the present invention provides a technical solution, a bending-resistant medium-voltage power cable, comprising an outer sheath 1, a plurality of cable cores 2 are installed at equal angles along the circumferential direction inside the outer sheath 1, and an active bending-resistant mechanism 200 is installed inside the outer sheath 1 at the outer side of the cable core 2;

[0045] The active bending resistance mechanism 200 includes a support pad 201, a protective tube 202, a convex plate 203, a concave plate 204, a guide head 205, a connecting tube 206, an air bag block 207, an elastic clamp 208, a delivery tube 209, a ring box 210, an oblique tube 211, a piston 212, a spherical plug 213, a clamp ear 214, a reinforcing rib 215, a clamp tube 216, a ball 217, a clamp sleeve 218, an air valve 219, a cable 220, a ring plate 221, an arc plate 222 and a sealing ring 223;

[0046] A plurality of support pads 201 are evenly and equidistantly installed inside the outer sheath 1, a protective tube 202 is installed in the middle of the side end face of the support pad 201, a plurality of convex plates 203 are installed at equal angles along the circumferential direction on the edge of the side end face of the support pad 201, a plurality of concave plates 204 are evenly and equidistantly installed on the side end face of the convex plate 203, a guide head 205 is installed at the end of the protective tube 202, a plurality of connecting tubes 206 are installed at equal angles along the circumferential direction on the outer curved surface of the guide head 205, an airbag block 207 is installed at the end of the connecting tube 206, both side end faces of the airbag block 207 are clamped with elastic clamps 208, a delivery tube 209 is installed on the outer curved surface of the airbag block 207, a ring box 210 is installed at the end of the delivery tube 209, and a plurality of inclined tubes 211 are installed at equal angles along the circumferential direction on the side end face of the ring box 210;

[0047] A piston 212 is symmetrically slidably installed inside the support pad 201, a spherical plug 213 is rollingly installed inside the protective tube 202, the inner cavity of the protective tube 202 is directly connected to the inner cavity of the support pad 201, an annular rib 2051 is symmetrically installed on the inner curved surface of the guide head 205, and the inner diameter of the annular rib 2051 is smaller than the outer diameter of the spherical plug 213, the piston 212 fits with the support pad 201, the spherical plug 213 fits with the protective tube 202, the position between the spherical plug 213 and the piston 212 in the protective tube 202 is filled with helium, and the position between the two pistons 212 in the inner cavity of the support pad 201 is filled with helium, so as to disperse and unload the external interference pressure;

[0048] A plurality of clamping ears 214 are evenly and evenly installed at the corners of the outer curved surfaces of the support pad 201 and the convex plate 203, and a reinforcing rib 215 is embedded and installed at the end of the clamping ear 214. A clamping tube 216 is installed on the outer curved surface of the airbag block 207. The inclined tube 211 is axially inclined relative to the cable core 2, and the two ends of the inclined tube 211 are connected to the inner cavities of the two adjacent ring boxes 210. The inner cavity of the airbag block 207 is connected to the inner cavity of the ring box 210 through the conveying tube 209, and the inner cavities of the two adjacent airbag blocks 207 are connected through the clamping tube 216 to guide the helium.

[0049] A plurality of balls 217 are installed at equal angles in a rolling manner along the circumferential direction on the inner curved surface of the elastic clamp 208 corresponding to the position of the cable core 2. A ferrule 218 is sleeved on the outer side of the cable core 2. The outer curved surface of the cable core 2 is covered with an insulating sleeve 3. A shielding sleeve 4 is embedded and installed on the outer side of the insulating sleeve 3 located at the inner side of the ferrule 218. A track groove 2181 is provided on the outer curved surface of the ferrule 218 corresponding to the position of the ball 217. The concave plate 204 and the ball 217 are both matched with the ferrule 218 to avoid the eccentric core misalignment inside the cable. The number of convex plates 203 is the same as the number of cable cores 2. The concave plate 204 and the convex plate 203 together form a hollow support structure, and the concave plate 204 and the convex plate 203 are integrally formed. The concave plate 204 is matched with the ferrule 218 to improve the internal density of the cable.

[0050] An air valve 219 is embedded and installed on one side of the outer curved surface of the ring box 210, and a number of straps 220 are installed at equal angles along the circumferential direction on the side end face edge of the guide head 205 located outside the protective tube 202, and a ring plate 221 is rotatably installed inside the guide head 205, and an arc plate 222 is installed on the side end face edge of the ring plate 221. A sealing ring 223 is rotatably connected to the other side end face of the guide head 205, and the width of the arc plate 222 is greater than the diameter of the connecting tube 206 to improve the stability of the joint, and a sealing ring 223 is installed on the side end face of the arc plate 222.

[0051] A parallel heat exchange mechanism 300 is installed outside the protective tube 202, and the parallel heat exchange mechanism 300 includes a special-shaped frame 301, an inner spacer 302, a shaft 303, a movable plug 304, a groove 305, a connecting hole 306, a stripe groove 307, a strip capsule 308, a non-woven fabric 309, a square tube 310, an inner sleeve 311, an outer sleeve 312, a moisture-proof cotton 313, a ring shell 314, a strip port 315, a strip rib 316 and an inlet and outlet 317;

[0052] A special-shaped frame 301 is installed inside the support pad 201 at a position between the two pistons 212, an inner spacer 302 is installed in the middle of the side end surface of the special-shaped frame 301, a shaft rod 303 is installed in the middle of the side end surface of the piston 212, and a movable plug 304 is installed at the end of the shaft rod 303 at a position inside the inner spacer 302. A groove 305 is opened at the middle of the outer curved surface of the support pad 201 corresponding to the position of the cable core 2, and a connecting hole 306 is opened at the outer curved surface of the inner spacer 302 corresponding to the groove 305. The difference between the length of the inner spacer 302 and the inner diameter of the connecting hole 306 is twice the length of the shaft rod 303. The length of the shaft rod 303 is the maximum distance between the piston 212 and the special-shaped frame 301, so as to convert the driving force. A plurality of striped grooves 307 are opened at equal angles along the circumferential direction on the side end surface of the groove 305.

[0053] The outer side of the protective tube 202 is filled with a strip capsule 308 at the inner side of the convex plate 203, non-woven fabrics 309 are embedded in the middle of the end faces of both sides of the strip capsule 308, a square tube 310 is installed in the middle of the outer curved surface of the strip capsule 308, the outer side of the airbag block 207 is sleeved with an inner sleeve 311 at the inner side of the ring box 210, and an outer sleeve 312 is sleeved on the outer side of the inner sleeve 311. The inner cavity of the strip capsule 308 is connected through the square tube 310 and the chamber surrounded by the inner sleeve 311 and the outer sleeve 312. The length of the strip capsule 308 is the same as that of the protective tube 202 for drainage guidance, and the inner side of the outer sleeve 312 is filled with moisture-proof cotton 313 at the outer side of the oblique tube 211;

[0054] The outer curved surface of the outer sleeve 312 is located at the inner side of the outer sleeve 1 and is evenly and evenly installed with a number of annular shells 314. The outer curved surface of the outer sleeve 312 is located at the inner side of the annular shell 314 and is provided with a number of strip openings 315 at equal angles along the circumferential direction. The outer curved surface of the outer sleeve 312 is located at the outer side of the annular shell 314 and is provided with a number of strip ribs 316 at equal angles along the circumferential direction. The side end surface of the annular shell 314 is provided with a number of inlets and outlets 317 at equal angles along the circumferential direction. The chamber enclosed by the inner sleeve 311 and the outer sleeve 312 is connected to the annular shell 314 through the strip openings 315. The annular shell 314 is positioned corresponding to the end of the square tube 310. The strip ribs 316 and the inlets and outlets 317 are adjacently distributed, and the strip ribs 316 are spirally shaped. The strip ribs 316 and the outer curved surface of the annular shell 314 are connected to the inner curved surface of the outer sleeve 1 to improve the comprehensiveness and balance of the heat exchange work.

[0055] Working principle and use process of the present invention: When the bending-resistant medium-voltage power cable is actually used, firstly, a cable of corresponding length is selected according to actual needs. During the wiring process of the cable, the cable length can also be trimmed and fine-tuned for a second time according to actual needs. During the trimming process of the cable, the position corresponding to the end of the guide head 205 is the best trimming position. After the length of the cable is trimmed, the corresponding parameters of the cable can be adaptively adjusted according to actual needs.

[0056] First, the opening of the guide head 205 at the end is blocked, and the external inflation device is connected to the air valve 219 on a ring box 210 at the end of the cable, and helium is injected into the ring box 210 through the air valve 219 by the external inflation device. Under the conduction effect of the inclined tube 211, the helium will flow into each ring box 210 in turn through each inclined tube 211, and will flow into each air bag block 207 synchronously under the conduction of the delivery tube 209. Then, the helium inside each ring box 210 will flow into the corresponding guide head 205 under the guidance of each connecting tube 206, and finally flow into the protective tube 202, squeezing the spherical plug 213, forcing the spherical plug 213 to roll along the protective tube 202 under the action of air pressure;

[0057] In the above process, as helium is filled into each ring box 210 and the inclined tube 211, the inclined tube 211 will be further tightened under the action of air pressure, and cooperate with the ring box 210 to provide circumferential support force to the outer sheath 1, so that the outer surface of the outer sheath 1 is fuller. As helium is filled into each airbag block 207, each airbag block 207 will expand accordingly under the action of air pressure, and elastically support the inner sleeve 311, so that the inner sleeve 311, the outer sleeve 312, the moisture-proof cotton 313, the ring shell 314 and the strip ribs 316 form The protective heat dissipation structure is more closely fitted to the outer sheath 1, and sufficient elastic support force is given to the elastic clamp 208, forcing the ball 217 to fit with the track groove 2181 on the clamping sleeve 218, and the cable core 2 is squeezed toward the concave plate 204, so that the concave plate 204 and the support pad 201 are both in contact with the clamping sleeve 218. In addition, the hollow support structure composed of the convex plate 203 and the concave plate 204 provides support for the clamping sleeve 218, and the cable core 2 can be buckled and limited, so that the internal structure of the cable is more closely fitted;

[0058] As the spherical plug 213 rolls along the protective tube 202, the helium between the spherical plug 213 and the piston 212 will be squeezed, causing the pressure of this part of the helium to rise synchronously with the pressure on the other side of the spherical plug 213, that is, to rise synchronously with the pressure inside the ring box 210. In actual use, the air pressure can be adjusted according to actual needs. Under the action of this air pressure, the oblique tube 211 and the protective tube 202 will tend to be in a straight state, that is, the greater the air pressure, the less likely the oblique tube 211 and the protective tube 202 are to be bent, and the bending radius of the cable will be correspondingly reduced, that is, after being bent, it will obtain more sufficient reset pressure, and can achieve rapid reset more efficiently, resulting in a synchronous increase in the toughness of the cable. For the convenience of description, this pressure is referred to as toughness air pressure here;

[0059] The increase of toughness air pressure will also make the elastic support force of the airbag block 207 given to the inner sleeve 311 and the elastic clamp 208 increase accordingly, so that the fitting force of each structure inside the cable increases synchronously, and give the outer sheath 1 more sufficient support force, thereby increasing the resistance threshold of the outer sheath 1 to external pressure, so that the outer sheath 1 will not be deformed under greater external pressure. It should be noted here that in actual use, in the process of adjusting the toughness air pressure, in addition to the use requirements, the maximum safety air pressure of the cable of this specification should also be referred to, that is, the helium pressure between the two pistons 212 inside the support pad 201 when they are in contact with the special-shaped frame 301 at the same time. The size of the toughness air pressure should be lower than the maximum safety air pressure. In the process of selecting cable specifications, the maximum safety air pressure given by the manufacturer and the required cable length can be comprehensively selected;

[0060] After completing the above work, rotate the sealing ring 223 on the guide head 205 at the end of the cable so that the arc plate 222 blocks the connecting pipe 206, further seals the end, and semi-isolates the protective tube 202 closest to the end. While retaining its pressure relief performance, it no longer accepts the shared air pressure transmitted from the airbag block 207, reducing the external pressure shared during use, thereby improving the overall pressure resistance and reducing the external interference pressure borne by the end. Then, the corresponding wiring work can be carried out, and it can be put into normal use after the wiring is completed;

[0061] During the use of the cable, when the cable is subjected to external pressure impact, when the external pressure exceeds the toughness air pressure, the oblique tube 211 and the airbag block 207 will both produce corresponding deformations under the external pressure impact, so that the air pressure inside the oblique tube 211 and the airbag block 207 at the pressure position rises. Here, when the air pressure is not greater than the maximum safety air pressure, they are all in normal working state. The helium inside the oblique tube 211 and the airbag block 207 at the pressure position will diffuse to the pressure points on both sides under the action of the air pressure. Under the conduction action of the clamping tube 216, it will diffuse to each airbag block 207 and be conducted along the helium flow path in the aforementioned process of adjusting the toughness air pressure, so as to preliminarily disperse and buffer the external impact pressure. For the convenience of description, the passage is uniformly referred to as the airflow passage below;

[0062] Finally, the air pressure will act on each spherical plug 213, forcing the spherical plug 213 to roll under the action of the air pressure, squeezing the helium between the spherical plug 213 and the piston 212, forcing the piston 212 to slide accordingly under the action of the helium, compressing the helium between the two pistons 212, and applying the air pressure to the other piston 212, which in turn squeezes the helium on the other side and applies the pressure to the spherical plug 213 adjacent thereto, thus dispersing and transmitting the external impact pressure to the pistons 212 and spherical plugs 213 inside each support pad 201 and protective tube 202 along the cable axis, and further dispersing and buffering the external impact pressure;

[0063] Similarly, after the cable is subjected to bending stress, when the external bending stress exceeds the toughness gas pressure, the helium inside the inclined tube 211 and the protective tube 202 will be compressed as the cable bends and deforms, causing the helium gas pressure to rise and diffuse from the bend to both sides. Under the conduction of the air flow path, the pressure is finally dispersed and applied to the pistons 212 and spherical plugs 213 inside each support pad 201 and the protective tube 202, and the bending stress is dispersed and converted into the helium internal pressure inside each protective tube 202. The helium internal pressure is superimposed on the toughness gas pressure to jointly resist the stress that forces the cable to bend.

[0064] After the impact pressure and bending stress applied externally disappear, the support of the external impact pressure and bending stress is lost, and the protective tube 202, the airbag block 207, the inclined tube 211, the piston 212 and the spherical plug 213 will all be reset under the action of the internal helium pressure, and the shape of the cable will also be reset accordingly. It is worth noting that: during the use of the cable, the presence of the piston 212 and the spherical plug 213 can disperse and buffer the external impact pressure, which can improve the pressure resistance and bending stress resistance of the cable. The compressibility of helium makes the pressure value superimposed by the toughness pressure after the external pressure disturbance higher than the maximum safety pressure for a short time, but it should be avoided that it is greater than the maximum safety pressure for a long time;

[0065] Similarly in the above process, that is, as the piston 212 moves, the shaft 303 will push the movable plug 304 to slide correspondingly inside the inner spacer 302. When the two movable plugs 304 approach each other, they will press the air inside the inner spacer 302 into the groove 305 through the connecting hole 306, and disperse into the gap between the convex plate 203 and the concave plate 204 through the strip groove 307, pass through the non-woven fabric 309 into the strip capsule 308, and enter the space between the inner sleeve 311 and the outer sleeve 312 through the square tube 310, and then enter the annular shell 314 through the strip opening 315, enter the gaps between the strip ribs 316 through the inlet and outlet 317, and flow along the gaps between the strip ribs 316 along the axial direction of the outer sheath 1 around the outer sheath 312, and finally flow out from the opening surrounded by the outer sheath 312, the strip ribs 316 and the outer sheath 1 at the end of the cable;

[0066] When the two movable plugs 304 move away from each other, the external airflow will flow into the inner partition tube 302 along the aforementioned passage direction, that is, when the cable is subjected to external bending stress and extrusion stress, as the cable is deformed and reset, the external stress can be further consumed and transformed, while reducing the impact force on the cable. At the same time, the external stress can be used to promote airflow exchange inside and outside the cable. The intersection of the internal and external airflows is located at the end of the cable, which can simultaneously promote heat exchange at the joint. At the same time, the heat dissipated during the use of the cable can be used to maintain the temperature stability of the cable surface to ensure the physical properties of the cable.

[0067] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bending-resistant medium-voltage power cable, comprising an outer sheath (1), characterized in that: A plurality of cable cores (2) are installed at equal angles in the circumferential direction inside the outer sheath (1), and an active bending resistance mechanism (200) is installed inside the outer sheath (1) at a position outside the cable core (2); The active bending resistance mechanism (200) comprises a support pad (201); A plurality of support pads (201) are evenly and equidistantly installed inside the outer protective sleeve (1); a protective tube (202) is installed in the middle of the side end surface of the support pad (201); a plurality of convex plates (203) are installed at equal angles along the circumferential direction on the edge of the side end surface of the support pad (201); a plurality of concave plates (204) are evenly and equidistantly installed on the side end surface of the convex plate (203); a guide head (205) is installed at the end of the protective tube (202); and the outer curved surface of the guide head (205) is arranged along the circumferential direction. A plurality of connecting tubes (206) are installed at equal angles in the circumferential direction, an airbag block (207) is installed at the end of the connecting tube (206), both side end surfaces of the airbag block (207) are clamped with elastic clamps (208), a delivery tube (209) is installed on the outer curved surface of the airbag block (207), a ring box (210) is installed at the end of the delivery tube (209), and a plurality of inclined tubes (211) are installed at equal angles along the circumferential direction on the side end surface of the ring box (210); A piston (212) is symmetrically and slidably mounted inside the support pad (201), a spherical plug (213) is rollingly mounted inside the protective tube (202), a plurality of clamping ears (214) are evenly and equidistantly mounted at the corners of the outer curved surfaces of the support pad (201) and the convex plate (203), a reinforcing rib (215) is embedded and mounted at the end of the clamping ear (214), a clamping tube (216) is mounted on the outer curved surface of the airbag block (207), a plurality of balls (217) are rollingly mounted at equal angles along the circumferential direction at the inner curved surface of the elastic clamp (208) corresponding to the position of the cable core (2), and a clamping sleeve (218) is sleeved on the outer side of the cable core (2); An air valve (219) is embedded and installed on one side of the outer curved surface of the ring box (210); a plurality of cables (220) are installed at equal angles along the circumferential direction at the edge of the side end surface of the guide head (205) located outside the protective tube (202); a ring plate (221) is rotatably installed inside the guide head (205); an arc plate (222) is installed on the edge of the side end surface of the ring plate (221); and a sealing ring (223) is installed on the side end surface of the arc plate (222).

2. A bending-resistant medium voltage power cable according to claim 1, characterized in that: The outer curved surface of the cable core (2) is coated with an insulating sleeve (3), a shielding sleeve (4) is embedded and installed on the outer side of the insulating sleeve (3) at a position inside the ferrule (218), a track groove (2181) is provided on the outer curved surface of the ferrule (218) at a position corresponding to the ball (217), and the concave plate (204) and the ball (217) are both fitted with the ferrule (218).

3. A bending-resistant medium voltage power cable according to claim 1, characterized in that: The inclined tube (211) is axially inclined relative to the cable core (2), and two ends of the inclined tube (211) are connected to the inner cavities of two adjacent ring boxes (210), the inner cavity of the airbag block (207) is connected to the inner cavity of the ring box (210) through the delivery tube (209), and the inner cavities of the two adjacent airbag blocks (207) are connected through the clamping tube (216).

4. A bending-resistant medium voltage power cable according to claim 1, characterized in that: The inner cavity of the protective tube (202) is directly connected to the inner cavity of the support pad (201); an annular rib (2051) is symmetrically mounted on the inner curved surface of the guide head (205); the inner diameter of the annular rib (2051) is smaller than the outer diameter of the spherical plug (213); the piston (212) fits with the support pad (201); the spherical plug (213) fits with the protective tube (202); the interior of the protective tube (202) is filled with helium at a position between the spherical plug (213) and the piston (212); and the inner cavity of the support pad (201) is filled with helium at a position between the two pistons (212).

5. A bending-resistant medium voltage power cable according to claim 1, characterized in that: The number of the convex plates (203) is the same as the number of the cable cores (2); the concave plates (204) and the convex plates (203) together form a hollow support structure; the concave plates (204) and the convex plates (203) are integrally formed; and the concave plates (204) fit in with the ferrules (218).

6. A bending-resistant medium voltage power cable according to claim 1, characterized in that: The sealing ring (223) is rotatably connected to the end surface of the other side of the guide head (205) in a sealing manner, and the width of the arc plate (222) is greater than the diameter of the connecting pipe (206).

7. A bending-resistant medium voltage power cable according to claim 1, characterized in that: A parallel heat exchange mechanism (300) is installed outside the protective tube (202), and the parallel heat exchange mechanism (300) comprises a special-shaped frame (301); A special-shaped frame (301) is installed inside the support pad (201) at a position between the two pistons (212), an inner spacer (302) is installed in the middle of the side end surface of the special-shaped frame (301), a shaft (303) is installed in the middle of the side end surface of the piston (212), a movable plug (304) is installed at the end of the shaft (303) at a position inside the inner spacer (302), a groove (305) is opened in the middle of the outer curved surface of the support pad (201) at a position corresponding to the cable core (2), a connecting hole (306) is opened on the outer curved surface of the inner spacer (302) at a position corresponding to the groove (305), and a plurality of striped grooves (307) are opened at equal angles along the circumferential direction on the side end surface of the groove (305); The outer side of the protective tube (202) is filled with a strip-shaped bag (308) at a position located inside the convex plate (203), non-woven fabrics (309) are embedded and installed in the middle of both side end surfaces of the strip-shaped bag (308), a square tube (310) is installed in the middle of the outer curved surface of the strip-shaped bag (308), the outer side of the airbag block (207) is sleeved with an inner sleeve (311) at a position located inside the ring box (210), the outer side of the inner sleeve (311) is sleeved with an outer sleeve (312), and the inner side of the outer sleeve (312) is filled with moisture-proof cotton (313) at a position located outside the inclined tube (211); The outer curved surface of the outer sleeve (312) is located inside the outer protective sleeve (1) and is evenly and evenly provided with a plurality of annular shells (314); the outer curved surface of the outer sleeve (312) is located inside the annular shell (314) and is provided with a plurality of strip-shaped openings (315) at equal angles in the circumferential direction; the outer curved surface of the outer sleeve (312) is located outside the annular shell (314) and is provided with a plurality of strip-shaped ribs (316) at equal angles in the circumferential direction; and the side end surface of the annular shell (314) is provided with a plurality of inlets and outlets (317) at equal angles in the circumferential direction.

8. A bending-resistant medium voltage power cable according to claim 7, characterized in that: The difference between the length of the inner spacer (302) and the inner diameter of the connecting hole (306) is twice the length of the shaft rod (303), and the length of the shaft rod (303) is the maximum distance between the piston (212) and the special-shaped frame (301).

9. A bending-resistant medium voltage power cable according to claim 7, characterized in that: The inner cavity of the strip-shaped capsule (308) is connected to a chamber enclosed by the inner sleeve (311) and the outer sleeve (312) through the square tube (310), and the length of the strip-shaped capsule (308) is the same as that of the protective tube (202).

10. A bending-resistant medium voltage power cable according to claim 7, characterized in that: The chamber enclosed by the inner sleeve (311) and the outer sleeve (312) is connected to the annular shell (314) through the strip opening (315); the annular shell (314) is located corresponding to the end of the square tube (310); the strip rib (316) and the inlet and outlet (317) are adjacently distributed; the strip rib (316) is spiral-shaped; and the outer curved surfaces of the strip rib (316) and the annular shell (314) are both connected to the inner curved surface of the outer sleeve (1).

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