A torsion-resistant wind energy cable

Abstract

The utility model provides a kind of torsion-resistant wind energy cable, including cable core, cable core includes talcum powder coating, insulating layer, isolation layer one and metal conductor;Metal conductor is made of copper wire bundle silk after with aramid yarn strand twist and form;The outer surface of metal conductor is longitudinally packed with isolation layer one, and the outer surface of isolation layer one is extruded and packed with insulating layer;The outer surface of insulating layer is coated with talcum powder to form talcum powder coating;Multiple cable core center is equipped with filling strip, and multiple cable core and filling strip outer surface are around isolation layer two;The outer surface of isolation layer two is woven with total shielding layer;The outer surface of total shielding layer is around with inner liner, and the outer surface of inner liner is extruded and packed with sheath layer.The utility model its metal conductor has high softness and tensile resistance;Cable core outer layer and inner layer are same direction twisted, so when cable is subjected to torsion, its outer twisted layer pitch circle and inner twisted layer pitch circle can be synchronous expansion or shrinkage, still can maintain close contact, so transverse relative displacement does not occur.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, specifically to an anti-torsion wind power cable. Background Technology

[0002] Due to the unique characteristics of wind power cables, such as long-term outdoor operation, vertical suspension laying, frequent torsion, contact with oil, and seawater corrosion, wind power cables have special performance requirements. These include sufficient mechanical strength, excellent electrical performance, and resistance to oil, ultraviolet radiation, and low temperatures. In particular, the requirements for torsional resistance are higher. This is because the better the flexibility, tensile and seismic performance, and torsional resistance of the wind power cable, the longer its service life will be.

[0003] Currently, most wind power control cables lack specialized conductor specifications and reinforced components. This makes them prone to internal stress during frequent torsion, leading to conductor breakage and even core breakage. This can cause short circuits or open circuits, and the difference in torsional force between the stranded core layers causes relative displacement, accelerating insulation wear. Furthermore, the metal shielding layer of most wind power control cables frequently experiences the same phenomenon of broken or fractured metal wires. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a torsion-resistant wind power cable that can solve the existing problems.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: This utility model is achieved through the following technical solution: an anti-torsion wind power cable, comprising a cable core, the cable core comprising a talc coating, an insulation layer, an isolation layer, and a metal conductor; the metal conductor is formed by twisting copper wire bundles with aramid yarn strands; an isolation layer is longitudinally wrapped around the outer surface of the metal conductor, and an insulation layer is extruded around the outer surface of the isolation layer; the outer surface of the insulation layer is coated with talc to form a talc coating; A filler strip is provided at the center of multiple cable cores, and an isolation layer two is wrapped around the outer surface of the multiple cable cores and the filler strip; a total shielding layer is woven on the outer surface of the isolation layer two; an inner lining layer is wrapped around the outer surface of the total shielding layer, and a sheath layer is extruded on the outer surface of the inner lining layer.

[0006] Furthermore, the metal conductor is made of aramid yarn strands and copper wire strands arranged in a 1+6 twisted direction, the diameter of the copper wire is 0.15mm or 0.20mm, and the aramid yarn is 1000D or 1500D; the bundles and twists of the metal conductor are in the same direction.

[0007] Furthermore, the first isolation layer includes an electrical insulating paper layer with a thickness of 0.020 mm to 0.040 mm; the second isolation layer includes a reinforced nonwoven fabric layer with a thickness of 0.10 mm to 0.20 mm; and the inner lining layer includes a thin polyester nonwoven fabric layer with a thickness of 0.10 mm to 0.20 mm.

[0008] Furthermore, the cable cores are arranged in a ring array with multiple layers from the inside out, and the multiple layers of cable cores are twisted together in the same direction within the second isolation layer.

[0009] Furthermore, the overall shielding layer is made by first twisting tin-plated copper wire and aramid yarn together and then weaving them together, with a weaving angle of 40° to 55°.

[0010] Furthermore, it also includes connector one and connector two, which are rotatably connected, and the other ends of connector one and connector two are respectively connected to the cables to be connected.

[0011] Furthermore, the first connector includes a sleeve, a socket, a protrusion, an elastic sealing ring, and a sealing ring; the sleeve connects to a cable, and a socket is provided inside the sleeve; the socket connects to the cable core; a sealing ring and an elastic sealing ring are fixed at the end of the sleeve, and a protrusion is provided on the inner side of the sleeve; the second connector includes an extension rod, a second protrusion, a pin, and a second sleeve; the second sleeve connects to a cable, and a pin is provided inside the sleeve; one end of the pin connects to the cable core, and the other end of the pin connects to the socket; a second protrusion is provided on the outer side of the second sleeve; the second protrusion connects to a groove on the inner wall of the first sleeve, and the first protrusion connects to a groove on the outer wall of the second sleeve; the sealing ring connects to the groove on the outer wall of the second sleeve.

[0012] Furthermore, the cross-section of the sealing ring adopts an inverted "E" shape, and the cross-section of the elastic sealing ring adopts an arc shape.

[0013] Furthermore, the second connector also includes an extension rod, the end of the pin adopts a spherical structure, and the side of the pin extends outward to form an extension rod; the end of the socket is adapted to the pin and the extension rod.

[0014] Compared with the prior art, the beneficial effects of this utility model include: This utility model discloses an anti-torsion wind power cable, in which the metal conductor is made of aramid yarn strands and copper wire strands arranged in a 1+6 pattern and twisted in the same direction. The conductor has high flexibility and tensile strength. When the metal conductor strands are re-twisted, an untwisting device is used to fully untwise the conductor during re-twisting. The conductor strands will not twist and there is no torsional internal stress in the strands, so there is no tendency to spring back and loosen. After re-twisting, the metal conductor structure is stable, soft and round.

[0015] The insulation layer of this invention can effectively prevent the conductor wires from puncturing the insulation during cable torsion, and the highly flexible ethylene propylene rubber also gives the cable high flexibility; the talc coating on the outside of the insulation layer can enhance the relative slippage ability of the insulated cores and improve the torsion resistance of the cable.

[0016] In this invention, the outer and inner layers of the cable core are twisted in the same direction. When the cable is subjected to torque, the pitch circle of the outer twisted layer and the pitch circle of the inner twisted layer will expand or shrink synchronously, maintaining close contact and preventing lateral relative displacement.

[0017] The overall shielding layer of this invention is made of tin-plated copper wire and aramid yarn, which are pre-twisted together and then woven. The aramid yarn has high strength and high modulus, and the combination of the two can effectively prevent the tin-plated copper wire from breaking when the cable is twisted. The weaving density is not less than 90%, which reduces the transfer impedance of the cable and improves the cable's electromagnetic interference resistance. Two layers of thin polyester non-woven fabric are wrapped around the overall shielding layer, which not only prevents the tin-copper wire braided overall shielding layer from retreating when the rubber sheath is extruded, but also reduces the weaving marks on the sheath surface, achieving two benefits at once.

[0018] The connector of this utility model adopts a composite contact structure of ball pin + extension rod to cooperate with the socket, which converts axial torsional force into rotational motion, realizes free rotation, completes dynamic torsion elimination, effectively solves the problem of early failure of traditional cable connectors under torsional conditions, and is particularly suitable for dynamic laying occasions. Attached Figure Description

[0019] The disclosure of this utility model is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings, the same reference numerals are used to refer to the same parts. Wherein: Figure 1 This is a schematic diagram of the overall structure of an anti-torsion wind power cable according to the present invention; Figure 2 This is a schematic diagram of the cable core structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the connector structure in an embodiment of the present invention.

[0020] The diagram is labeled as follows: 1. Cable core; 11. Talc coating; 12. Insulation layer; 13. Insulation layer one; 14. Metal conductor; 2. Insulation layer two; 3. Overall shielding layer; 4. Inner lining layer; 5. Sheath layer; 6. Filler strip; 7. Connector one; 71. Sleeve one; 72. Socket; 73. Protrusion one; 74. Elastic sealing ring; 75. Sealing ring; 8. Connector two; 81. Outer rod; 82. Protrusion two; 83. Pin; 84. Sleeve two. Detailed Implementation

[0021] It is readily understood that, based on the technical solution of this utility model, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this utility model. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative descriptions of the technical solution of this utility model and should not be considered as the entirety of this utility model or as limitations or restrictions on the technical solution of this utility model.

[0022] Example 1 This utility model proposes a torsion-resistant wind power cable, such as Figure 1 As shown, the cable includes a cable core 1, which comprises a talc coating 11, an insulation layer 12, an insulating layer 13, and a metal conductor 14; as Figure 2 As shown, The metal conductor 14 is formed by twisting copper wire bundles with aramid yarn strands. Specifically, the metal conductor 14 is formed by first bundling multiple extra-soft, uniformly elongated tin-plated copper wires or bare copper wires, then twisting them with twisted aramid yarn strands in a 1 (aramid yarn strand) + 6 (copper wire strand) arrangement. The diameter of the copper wires is 0.15mm or 0.20mm, the aramid yarn specification is 1000D or 1500D, the number of aramid yarn strands is 4 to 16, the pitch ratio of the bundled strands is controlled at 15 to 18 times, and the pitch ratio of the outermost layer of the twisted strands is controlled at 6 to 10 times. The bundled strands and the twisting direction are consistent; for example, all are twisted to the left. The equipment used for twisting must be a de-twisting device, such as a cage twister. The metal conductor 14 of this invention, formed by twisting aramid yarn strands and copper wire strands in a 1+6 arrangement in the same direction, possesses high flexibility and tensile strength. When the 14 strands of the metal conductor are re-stranded, an untwisting device is used to ensure that the conductor is fully untwisted during re-stranding. The conductor strands will not twist and there will be no torsional internal stress in the strands, so there will be no tendency to spring back and loosen. With the use of a fully untwisting device, the structure of the 14 strands of the metal conductor is stable, soft and round after re-stranding.

[0023] An insulating layer 13 is longitudinally wrapped around the outer surface of the metal conductor 14. The insulating layer 13 is made of electrical insulating paper and has a thickness of 0.020 mm to 0.040 mm.

[0024] An insulating layer 12 is extruded onto the outer surface of the insulating layer 13. The insulating layer 12 is made of high-strength, highly flexible, and low-temperature resistant ethylene propylene rubber. The original tensile strength of the insulating layer 12 is not less than 8.5 MPa, and the elongation at break is not less than 350%. The insulating layer 12 is aged in an air oven at 135℃±3℃ for 168 hours. The retention rate of tensile strength is not less than 80% of the original tensile strength, and the retention rate of elongation at break is not less than 80% of the original elongation at break. The insulating layer 12 undergoes low-temperature tensile testing at -40℃ for 4 hours, with a minimum elongation of not less than 100%. The insulating layer 12 is also tested for ozone resistance; with an ozone concentration (by volume) of 0.025%–0.030%, the duration of the crack-free test is not less than 30 hours. The thickness of the insulating layer 12 is 0.6 mm–1.2 mm.

[0025] The outer surface of the insulation layer 12 is coated with talc powder to form a talc powder coating 11. The insulation layer 12 of this invention uses high-strength, highly flexible, and low-temperature resistant ethylene propylene rubber. The high strength of the ethylene propylene rubber insulation effectively prevents the conductor wires from puncturing the insulation during cable torsion, while the highly flexible ethylene propylene rubber gives the cable high flexibility. The talc powder coating 11, formed by uniformly coating sufficient talc powder onto the outside of the insulation layer 12, enhances the relative slippage ability of the insulated cores and improves the cable's torsion resistance.

[0026] A filler strip 6 is provided at the center of multiple cable cores 1. The cable cores 1 are arranged in a ring array with multiple layers from the inside out, and the multiple layers of cable cores 1 are twisted in the same direction within the second insulating layer 2. The outer surfaces of the multiple cable cores 1 and the filler strip 6 are wrapped around the second insulating layer 2. For example, 34 cable cores are used, with the number being 6, 12, and 18 from the inside out. The twisting direction is right-handed, and there is a filler strip 6 at the center of each cable core 1. The pitch ratio of the outermost layer of the cable is controlled at 8 to 10 times. When the cable is twisted and subjected to torque, if the outer layer of the adjacent twisted layer has a twisting direction opposite to the torque direction, and the inner layer has a twisting direction in the same direction as the torque direction, the pitch circle of the outer layer will expand outward, and the pitch circle of the inner layer will shrink inward, thereby causing loosening between the outer and inner layers. The insulated cores of the outer layer will loosen and shift. In another scenario, when the cable is subjected to torque during twisting, if the outer layer of an adjacent stranded layer is twisted in the same direction as the torque, while the inner layer is twisted in the opposite direction, the pitch circle of the outer layer will shrink inward, and the pitch circle of the inner layer will expand outward, causing the inner insulation core to bulge and crack. Therefore, only when the outer and inner layers of the stranded layer are twisted in the same direction can the pitch circles of the outer and inner stranded layers expand or shrink synchronously when the cable is subjected to torque, maintaining close contact and preventing lateral relative displacement. Therefore, this invention employs a right-hand twisting direction for each layer.

[0027] The second insulating layer 2 includes a reinforced nonwoven fabric layer with a thickness of 0.10mm to 0.20mm; the wrapping overlap rate is 15% to 40%, and the polyester side of the reinforced nonwoven fabric faces inward during wrapping. Using reinforced nonwoven fabric as the insulating layer outside the cable core, with the polyester film facing inward (towards the cable core) during wrapping, enhances the relative slippage capability between the insulation layer and the tinned copper wire braided overall shielding layer, thus giving this invention excellent torsional resistance.

[0028] The outer surface of the second isolation layer 2 is woven with a total shielding layer 3. The total shielding layer 3 is made by pre-twisting tin-plated copper wire and aramid yarn together before weaving, with a weaving angle of 40° to 55°. The weaving density is not less than 90%. The total shielding layer 3 is made by pre-twisting tin-plated copper wire and aramid yarn together. Aramid yarn has high strength and high modulus; the combination of the two effectively prevents the tin-plated copper wire from breaking when the cable is twisted. The weaving density of not less than 90% reduces the cable's transfer impedance and improves the cable's electromagnetic interference resistance.

[0029] The outer surface of the total shielding layer 3 is wrapped with an inner lining layer 4, which includes a thin polyester non-woven fabric layer with a thickness of 0.10mm to 0.20mm. The inner lining layer 4 is wrapped with two overlapping layers in a left-right direction, with an overlap rate of 15% to 40%. The tin-copper wire braided total shielding layer 3 is wrapped with two layers of thin polyester non-woven fabric, which not only prevents the tin-copper wire braided total shielding layer from shifting backward during the extrusion of the rubber sheath, but also reduces the braiding marks on the sheath surface, achieving two benefits in one step.

[0030] The outer surface of the inner liner 4 is extruded with a sheath layer 5. The sheath layer 5 is made of high-strength, high-flexibility, low-temperature resistant chlorosulfonated polyethylene compound, chloroprene rubber compound, or chlorinated polyethylene compound. The original tensile strength of the sheath layer is not less than 12.0 MPa, and the elongation at break is 350%. The sheath layer is aged in an air oven at 120℃±3℃ for 168 hours, retaining at least 70% of its original tensile strength and at break at least 70% of its original elongation at break. The sheath layer undergoes low-temperature tensile testing at -40℃ for 4 hours, with a minimum elongation at break of not less than 100%. The sheath layer is tested for mineral oil resistance at 100℃±2℃ for 24 hours, retaining at least 70% of its original tensile strength and at break at least 70% of its original elongation at break. The thickness of the sheath layer is 1.4 mm to 4.6 mm. The sheath layer 5 is made of high-strength, high-softness, low-temperature resistant chlorosulfonated polyethylene compound, neoprene rubber compound, or chlorinated polyethylene compound, which has good properties such as aging resistance, UV resistance, oil resistance, moisture resistance, tear resistance, wear resistance, flame retardancy, and resistance to sunlight aging.

[0031] The maximum long-term operating temperature of this invention reaches 90℃, and the minimum operating temperature reaches -40℃. Torsional resistance: At room temperature, the cable should withstand 10,000 cycles (±4 cycles per cycle); at -40℃, the cable should withstand 2,000 cycles (±4 cycles per cycle); at +60℃, the cable should withstand 10,000 cycles (±4 cycles per cycle); under load torsion, with current applied during torsion to bring the conductor temperature to the maximum operating temperature of 90℃, the cable should withstand 10,000 cycles (±4 cycles per cycle). After the above torsion tests, the cable surface should show no cracks or twisting; the cable should undergo an AC withstand voltage test of 2.5kV / 5min (rated voltage 450 / 750V) or 3.5kV / 5min (rated voltage 0.6 / 1kV) without insulation breakdown.

[0032] This invention not only possesses excellent resistance to low temperatures, torsion, heat aging, mineral oil, ultraviolet radiation, and salt spray, but more importantly, it also meets RoHS environmental protection standards and has flame-retardant properties. It is particularly suitable for applications with high environmental requirements.

[0033] Example 2 To prevent the transmission of torsional force when the cable is twisted, thus affecting all cables, and to prevent the joint from breaking due to torsional force, this utility model is designed with a special anti-torsion joint.

[0034] like Figure 3 As shown, it also includes connector 7 and connector 8, which are rotatably connected, and the other ends of connector 7 and connector 8 are respectively connected to the cables to be connected.

[0035] The first connector 7 includes a sleeve 71, a socket 72, a protrusion 73, an elastic sealing ring 74, and a sealing ring 75; the sleeve 71 is used to connect a cable, and the socket 72 is provided inside the sleeve 71; the socket 72 is connected to the cable core 1; the end of the sleeve 71 is fixed with a sealing ring 75 and an elastic sealing ring 74, and the inner side of the sleeve 71 is provided with a protrusion 73; the second connector 8 includes an extension rod 81, a protrusion 82, a pin 83, and a sleeve. 84; the second sleeve 84 is used to connect the cable, and the second sleeve 84 has a pin 83 inside; one end of the pin 83 is used to connect the cable core 1, and the other end of the pin 83 is used to connect the socket 72; the outer wall of the second sleeve 84 has a second protrusion 82; the second protrusion 82 is used to connect the groove opened in the inner wall of the first sleeve 71, and the first protrusion 73 is used to connect the groove in the outer wall of the second sleeve 84; the sealing ring 75 is used to connect the groove in the outer wall of the second sleeve 84. The connection between the first sleeve 71 and the second sleeve 84, and between the pin 83 and the socket 72, are rotatable. The sealing ring 75, the elastic sealing ring 74, and the protrusion are used to enhance the sealing performance of the joint connection.

[0036] The cross-section of the sealing ring 75 adopts an inverted "E" shape, and the cross-section of the elastic sealing ring 74 adopts an arc shape.

[0037] The connector 8 further includes an extension rod 81. The end of the pin 83 has a spherical structure, and the side of the pin 83 extends outward to form the extension rod 81. The end of the socket 72 is adapted to the pin 83 and the extension rod 81.

[0038] When connecting two cables, one cable is inserted into sleeve 2 84, with its inner core entering and contacting pin 83; the other cable is inserted into sleeve 1 71, with its inner core entering socket 72. The connection between the cable and the sleeve can be reinforced and sealed using one or more methods such as locking clamps, glue, or tape. If either cable twists, the connector can be rotated to eliminate the twist.

[0039] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0040] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "several" means two or more, unless otherwise explicitly specified.

[0042] The technical scope of this utility model is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this utility model, and all such modifications and variations should fall within the protection scope of this utility model.

Claims

1. A torsion-resistant wind power cable, characterized in that: The cable core (1) includes a talc coating (11), an insulation layer (12), an isolation layer (13), and a metal conductor (14). The metal conductor (14) is formed by twisting copper wire bundles with aramid yarn strands. The outer surface of the metal conductor (14) is longitudinally wrapped with an isolation layer (13), and the outer surface of the isolation layer (13) is extruded with an insulation layer (12). The outer surface of the insulation layer (12) is coated with talc to form a talc coating (11). A filler strip (6) is provided at the center of a plurality of cable cores (1), and an isolation layer (2) is wrapped around the outer surface of the plurality of cable cores (1) and the filler strip (6); a total shielding layer (3) is woven on the outer surface of the isolation layer (2); an inner lining layer (4) is wrapped around the outer surface of the total shielding layer (3), and a sheath layer (5) is extruded on the outer surface of the inner lining layer (4).

2. The anti-torsion wind power cable according to claim 1, characterized in that: The metal conductor (14) is made of aramid yarn strands and copper wire strands twisted in the same direction. The diameter of the copper wire is 0.15mm or 0.20mm, and the aramid yarn is 1000D or 1500D.

3. The anti-torsion wind power cable according to claim 1, characterized in that: The first isolation layer (13) includes an electrical insulating paper layer, and the thickness of the first isolation layer (13) is 0.020mm to 0.040mm; the second isolation layer (2) includes a reinforced nonwoven fabric layer, and the thickness of the second isolation layer (2) is 0.10mm to 0.20mm; the inner lining layer (4) includes a thin polyester nonwoven fabric layer, and the thickness of the inner lining layer (4) is 0.10mm to 0.20mm.

4. The anti-torsion wind power cable according to claim 1, characterized in that: The cable core (1) is arranged in a ring array with multiple layers from the inside to the outside, and the multiple layers of cable core (1) are twisted together in the same direction in the second isolation layer (2).

5. The anti-torsion wind power cable according to claim 1, characterized in that: The total shielding layer (3) is made by first twisting tin-plated copper wire and aramid yarn together and then weaving them together, with a weaving angle of 40° to 55°.

6. The anti-torsion wind power cable according to claim 1, characterized in that: It also includes connector one (7) and connector two (8), which are rotatably connected, and the other ends of connector one (7) and connector two (8) are respectively connected to the cables to be connected.

7. The anti-torsion wind power cable according to claim 6, characterized in that: The first connector (7) includes a sleeve (71), a socket (72), a protrusion (73), an elastic sealing ring (74), and a sealing ring (75); the sleeve (71) is used to connect a cable, and the socket (72) is provided inside the sleeve (71); the socket (72) is connected to the cable core (1); the end of the sleeve (71) is fixed with a sealing ring (75) and an elastic sealing ring (74), and the inner side of the sleeve (71) is provided with a protrusion (73); the second connector (8) includes a protrusion (82), a pin (83), and a sleeve. (84); the second sleeve (84) is used to connect the cable, and the second sleeve (84) is provided with a pin (83); one end of the pin (83) is used to connect the cable core (1), and the other end of the pin (83) is used to connect the socket (72); the second sleeve (84) is provided with a second protrusion (82) on the outside; the second protrusion (82) is used to connect the groove opened in the inner wall of the first sleeve (71), and the first protrusion (73) is used to connect the groove in the outer wall of the second sleeve (84); the sealing ring (75) is used to connect the groove in the outer wall of the second sleeve (84).

8. The anti-torsion wind power cable according to claim 7, characterized in that: The cross-section of the sealing ring (75) adopts an inverted "E" shape, and the cross-section of the elastic sealing ring (74) adopts an arc shape.

9. A torsion-resistant wind power cable according to claim 8, characterized in that: The connector 2 (8) also includes an extension rod (81), the end of the pin (83) adopts a spherical structure, and the side of the pin (83) extends outward to form an extension rod (81); the end of the socket (72) is adapted to the pin (83) and the extension rod (81).

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