CN104036873B - Shielded data cable suitable for repeated bending - Google Patents

Abstract

The invention discloses a shielded data cable suitable for repeated bending, which comprises eight copper conductor units and an aramid fiber reinforcing member, wherein each copper conductor unit comprises an aramid fiber, an inner conductive layer and an outer conductive layer which are positioned in the center; four symmetrical insulated wire pairs are twisted on the outer surface of the aramid fiber reinforcement to form a cable core; a second polytetrafluoroethylene layer longitudinally wraps the outer surface of the cable core, and a plurality of cotton yarns are filled in gaps between the second polytetrafluoroethylene layer and the four symmetrical insulating line pairs; a cotton fiber wire is wound on the outer surface of the second polytetrafluoroethylene layer to form a buffer sliding layer, the winding direction of the cotton fiber wire is opposite to the twisting direction of the four symmetrical insulated wire pairs, and a plurality of metal wires are wound on the outer surface of the buffer sliding layer side by side to form a metal shielding layer; a plurality of metal wires twine side by side in buffer sliding layer outer surface forms the metal shielding layer, and the metal wire surface all winds the third polytetrafluoroethylene area in this metal shielding layer. The data cable has the advantages of small friction coefficient, flexibility, stretch resistance, no friction static generation and stable structure and electrical performance after frequent movement.

Description

Shielded data cable suitable for repeated bending

technical field

The invention relates to a data cable, in particular to a shielded data cable suitable for repeated bending.

Background technique

The structure of the traditional shielded data cable is composed of 4 sets of symmetrical signal wire pairs, wrapped with a layer of polyester tape, and then wrapped with a layer of aluminum-plastic composite tape for shielding, and the outer layer is extruded with PVC or other plastic coatings. . Symmetrical signal pairs are formed by the assembly of two copper conductors with an insulated wire covered by a layer of high-density polyethylene. Product performance conforms to the specification requirements of TIA/EIA568B.2. In order to solve the problem of electrical performance attenuation and electromagnetic interference at lower frequencies, some products are designed to braid a layer of copper wire shielding on the outer layer of the aluminum-plastic composite tape. For shielded data cables that require movement, the conductors of the symmetrical signal pairs are replaced with multiple copper stranded conductors. The data cable with this structure can guarantee the transmission performance when it is used in fixed laying and mobile occasions. However, for environments with frequent movements such as robotic arms and relatively harsh environmental conditions, the performance reliability of this type of product cannot meet the requirements. After hundreds of movements, problems such as conductor breakage, increased attenuation, and decreased anti-interference performance will occur. . In the process of moving, there is friction between the insulation, the insulation and the outer tape, and the shield. On the one hand, it is easy to generate static electricity and cause signal interference. At the same time, frequent friction will also cause the mechanical and physical properties of the insulation material to decline. A general mechanical arm will require more than 100,000 movements. If the influence of the sliding of the cable core structure cannot be solved, the problems of product fatigue resistance and shielding stability cannot be solved, and the signal transmission requirements of the mechanical arm cannot be guaranteed. At this point, it is difficult for the traditional cable structure to meet the requirements.

How to design a data cable that can ensure stable signal transmission during more than 100,000 frequent reciprocating movements has become the direction of efforts of those skilled in the art.

Contents of the invention

The invention provides a shielded data cable suitable for repeated bending. The shielded data cable suitable for repeated bending has a small friction coefficient, is soft and stretch-resistant, has no frictional static electricity generation, and can still ensure a stable structure of the data cable after frequent movement. The tensile strength of the cable is increased by 50%, the number of times of bending resistance is increased by 300-500%, and the attenuation change value of 10,000 times of bending is less than 2%.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a shielded data cable suitable for repeated bending, including: eight copper conductor units and aramid fiber reinforcements, and the outer surface of the copper conductor units is covered with an insulating polypropylene layer , the copper conductor unit includes an aramid fiber at the center, an inner conductive layer composed of several first copper wires twisted on the outer surface of the aramid fiber, and a plurality of second copper wires twisted outside the inner conductive layer An outer conductor layer is formed on the surface;

The eight copper conductor units are twisted in pairs to form the first, second, third and fourth symmetrical insulated wire pairs, and the outer surfaces of each are wrapped with a first polytetrafluoroethylene tape, and the first, second , the third and fourth symmetrical insulated wire pairs are twisted on the outer surface of the aramid fiber reinforcement to form a cable core;

A second polytetrafluoroethylene layer longitudinally covers the outer surface of the cable core, and the gaps between the second polytetrafluoroethylene layer and the first, second, third and fourth symmetrical insulated wire pairs are filled with several cotton yarns ;

A cotton fiber wire is wound on the outer surface of the second polytetrafluoroethylene layer to form a buffer sliding layer, and the winding direction of the cotton fiber wire is opposite to the twisting direction of the first, second, third and fourth symmetrical insulated wire pairs;

A plurality of metal wires are wound side by side on the outer surface of the buffer sliding layer to form a metal shielding layer, and the outer surface of the metal wires in the metal shielding layer is wrapped with a third polytetrafluoroethylene tape, and the third polytetrafluoroethylene tape is wound The direction is opposite to the winding direction of the cotton fiber thread;

An outer sheath coats the outer surface of the third polytetrafluoroethylene layer.

Further improvement technical scheme in above-mentioned technical scheme is as follows:

In the above solution, the cotton fiber thread is sparsely wound on the outer surface of the second polytetrafluoroethylene layer.

Due to the use of the above-mentioned technical solutions, the present invention has the following advantages compared with the prior art:

1. The present invention is suitable for shielded data cables that are repeatedly bent, and the outer surfaces of the first, second, third and fourth symmetrical insulated wire pairs are wrapped with a first polytetrafluoroethylene tape and twisted to form a cable core. The second polytetrafluoroethylene layer longitudinally wraps the outer surface of the cable core, and in the frequent bending process, it overcomes the distance and pitch between the first, second, third and fourth symmetrical insulated wires and their respective copper conductor units. The distance changes, thereby causing changes in electrical performance; and in the frequent bending process, the first, second, third and fourth symmetrical insulated wire pairs are wrapped with the first polytetrafluoroethylene tape on their respective outer surfaces, and the second The two polytetrafluoroethylene layers cover the symmetrical insulated wire pairs with four first polytetrafluoroethylene tapes by longitudinal wrapping, because the first polytetrafluoroethylene tape and the second polytetrafluoroethylene layer have low friction coefficient and high strength High, corrosion resistance, good insulation performance, the friction coefficient of the strip is 0.04, which is the material with the lowest friction coefficient among solid materials at present, and it is covered by longitudinal wrapping in front of the metal shielding layer to reduce the friction caused by the wrapping structure. The increase of friction caused by lap joints minimizes the impact of structural changes in the cable core during frequent bending; secondly, due to the reduction of friction and the fact that the PTFE tape is not easy to generate static electricity, it also greatly reduces the generation of static electricity and improves performance. reliability and security.

2. The present invention is suitable for repeatedly bending shielded data cables, the gaps between the second polytetrafluoroethylene layer and the first, second, third and fourth symmetrical insulated wire pairs are filled with several cotton yarns, one cotton The fiber wire is wound on the outer surface of the second polytetrafluoroethylene layer to form a buffer sliding layer. The winding direction of the cotton fiber wire is opposite to the twisting direction of the first, second, third and fourth symmetrical insulated wire pairs. The wire is wound on the outer surface of the buffer sliding layer to form a metal shielding layer. In this metal shielding layer, the metal wires are wound side by side and opposite to the cotton fiber thread, so as to ensure that the copper wire has enough moving position without stretching when bending. The wire is broken, and at the same time, it is easier to slide between the copper wire and the insulating sliding layer without electrostatic interference. This structure can not only ensure the softness of the cable, but also ensure the shielding effect after frequent bending.

3. The present invention is suitable for repeatedly bending shielded data cables, a second polytetrafluoroethylene layer is sequentially arranged between the cable core and the outer sheath layer, and a cotton fiber thread is wound on the second polytetrafluoroethylene layer The outer surface forms a buffer sliding layer, and several metal wires are wound side by side on the buffer sliding layer to form a metal shielding layer. The outer surface of the metal wires in the metal shielding layer is wrapped with a third polytetrafluoroethylene tape. The winding direction of the vinyl fluoride tape is opposite to the winding direction of the cotton fiber wire; it avoids electrostatic interference between the outer sheath and the shielding layer during the reciprocating movement of the cable, and improves the electrical performance; at the same time, the performance of the polytetrafluoroethylene tape It is relatively soft and smooth, and will not affect the softness of the cable. The smooth surface makes it easy to slide between the cable core, metal shielding layer and outer sheath during bending, reducing the stretching of the cable by external force and prolonging the service life. life.

4. The shielded data cable suitable for repeated bending of the present invention has a copper conductor unit comprising an aramid fiber at the center, an inner conductive layer composed of several first copper wires twisted on the outer surface of the aramid fiber, and a plurality of first copper wires twisted on the outer surface of the aramid fiber. The second copper wire is stranded on the outer surface of the inner conductive layer to form an outer conductor layer, which improves the tensile strength and ensures the stability of the aramid fiber in the center of the cable structure; the first, second, third and fourth symmetrical insulation The wire pairs are twisted on the outer surface of an aramid fiber reinforcement to form a cable core; the cable structure is guaranteed to be stable, the tensile strength of the product is increased by 50%, the number of bending resistance is increased by 300~500%, and the attenuation change value of 10,000 bending times is less than 2 %.

5. The present invention is suitable for shielded data cables that are repeatedly bent. The direction of the cable core, the direction of the buffer layer, and the direction of the shielding layer are reversed in turn, forming relatively parallel circular surfaces. The relative sliding between the layers reduces the tensile force of the cable core and improves the bending resistance. The wrapping direction of different PTFE tapes is opposite to that of the inner layer's cable or wire winding direction, which can ensure the roundness of the structure. The sliding friction between different layers is reduced to the minimum, and the damage to the cable structure is reduced when the cable is bent, thereby improving the bending resistance and reducing the attenuation change rate during frequent bending.

Description of drawings

Accompanying drawing 1 is the structure diagram of the shielded data cable suitable for repeated bending of the present invention;

Accompanying drawing 2 is the structure schematic diagram of buffer sliding layer and metal shielding layer of the present invention;

Accompanying drawing 3 is A-A sectional structure schematic diagram in accompanying drawing 2;

Accompanying drawing 4 is the structural representation of metal wire of the present invention and the 3rd polytetrafluoroethylene layer;

Accompanying drawing 5 is the structural diagram of copper conductor unit of the present invention.

In the above drawings: 1. Copper conductor unit; 2. Insulated polypropylene layer; 3. The first symmetrical insulated pair; 4. The second symmetrical insulated pair; 5. The third symmetrical insulated pair; 6. The fourth symmetrical Insulated wire pair; 7. First polytetrafluoroethylene tape; 8. Cable core; 9. Second polytetrafluoroethylene layer; 10. Cotton yarn; 12. Buffer sliding layer; 13. Metal wire; 14. Metal shielding layer; 15. The third polytetrafluoroethylene layer; 16. The outer sheath layer; 17. Cotton fiber thread; 20. Aramid fiber; 21. Aramid reinforcement; 22. The first copper wire; 23. The second copper wire.

detailed description

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Embodiment: A shielded data cable suitable for repeated bending, including: eight copper conductor units 1 and aramid fiber reinforcement 21, the outer surface of the copper conductor units 1 is covered with an insulating polypropylene layer 2, and the copper conductor units 1 includes an aramid fiber 20 at the center, an inner conductive layer composed of several first copper wires 22 twisted on the outer surface of the aramid fiber 20, and a plurality of second copper wires 23 twisted on the outer surface of the inner conductive layer Form the outer conductor layer;

The eight copper conductor units 1 are twisted in pairs to form the first, second, third and fourth symmetrical insulated wire pairs 3, 4, 5, 6, and the outer surfaces of each are wrapped with a first polytetrafluoroethylene tape 7. The first, second, third and fourth symmetrical insulated wire pairs 3, 4, 5, 6 are stranded on the outer surface of the aramid fiber reinforcement 21 to form a cable core 8;

A second polytetrafluoroethylene layer 9 longitudinally wraps the outer surface of the cable core 8, and the second polytetrafluoroethylene layer 9 is connected to the first, second, third and fourth symmetrical insulated wire pairs 3, 4, 5 The gap between 6 and 6 is filled with several cotton yarns 10;

In the frequent bending process, the distance and pitch between the first, second, third and fourth symmetrical insulated wires and the respective copper conductor units are changed, thereby causing changes in electrical performance; and the frequent bending process Among them, the outer surfaces of the first, second, third and fourth symmetrical insulated wire pairs are wrapped with a first polytetrafluoroethylene tape, and the second polytetrafluoroethylene layer is wrapped with four fourth A symmetrical insulated pair of polytetrafluoroethylene tapes, because the first polytetrafluoroethylene tape and the second polytetrafluoroethylene layer have low friction coefficient, high strength, corrosion resistance, and good insulation performance, the friction coefficient of the tape is 0.04, which is the material with the lowest friction coefficient among solid materials at present, and it is covered by longitudinal wrapping in front of the metal shielding layer to reduce the increase of friction caused by the lap joint caused by the wrapping structure, so that the cable core will The impact of structural changes is minimized; secondly, due to the reduction of friction and the PTFE belt is not easy to generate static electricity, it also greatly reduces the generation of static electricity, improving performance reliability and safety;

A cotton fiber thread 17 is wound on the outer surface of the second polytetrafluoroethylene layer 9 to form a buffer sliding layer 12, and the winding direction of the cotton fiber thread 17 is the same as that of the first, second, third and fourth symmetrical insulated wire pairs 3, 4, 5, and 6 are twisted in opposite directions; when bending, the copper wire has enough moving position without stretching to cause disconnection, and at the same time, it is easier to slide between the copper wire and the insulating sliding layer without generating electrostatic interference. It can not only ensure the flexibility of the cable, but also ensure the shielding effect after frequent bending;

A plurality of metal wires 13 are wound side by side on the outer surface of the buffer sliding layer 12 to form a metal shielding layer 14, and the outer surface of the metal wires 13 in the metal shielding layer 14 is wrapped with a third polytetrafluoroethylene tape 15. The winding direction of the polytetrafluoroethylene tape 15 is opposite to the winding direction of the cotton fiber line 17; it avoids electrostatic interference between the outer sheath and the shielding layer during the reciprocating movement of the cable, and improves the electrical performance; at the same time, the polytetrafluoroethylene The performance of the vinyl tape is relatively soft and smooth, which will not affect the softness of the cable. The smooth surface makes it easy to slip between the cable core, metal shielding layer and outer sheath during the bending process, reducing the pull of the external force on the cable. Stretch, prolong service life;

An outer sheath layer 16 covers the outer surface of the third polytetrafluoroethylene layer 15 . A buffer is formed between the metal shielding layer and the outer sheath to avoid electrostatic interference between the outer sheath and the shielding layer during the reciprocating movement of the cable. At the same time, the performance of the PTFE tape is relatively soft and smooth, which will not affect the softness of the cable. Through the process control of the sheath extrusion, the smooth surface makes it easy to produce friction between the cable core and the sheath during the bending process. Sliding, reducing the stretching of copper conductor and tinned copper wire braid by external force, prolonging the service life.

The above-mentioned cotton fiber thread 17 is sparsely wound on the outer surface of the second polytetrafluoroethylene layer 9 .

The performance test data are shown in Table 1:

Table 1

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (1)

1. A shielded data cable suitable for repeated bending, characterized in that it includes: eight copper conductor units (1) and aramid fiber reinforcement (21), the outer surface of the copper conductor unit (1) is covered with insulating poly The acrylic layer (2), the copper conductor unit (1) includes an aramid fiber (20) at the center, and an inner core composed of several first copper wires (22) twisted on the outer surface of the aramid fiber (20) The conductive layer is formed by twisting a plurality of second copper wires (23) on the outer surface of the inner conductive layer to form an outer conductor layer; The eight copper conductor units (1) are twisted in pairs to form the first, second, third and fourth symmetrical insulated wire pairs (3, 4, 5, 6), and the outer surfaces of each are wrapped with the first poly Tetrafluoroethylene tape (7), the first, second, third and fourth symmetrical insulated wire pairs (3, 4, 5, 6) are twisted on the outer surface of the aramid reinforcement (21) to form a cable core(8); A second polytetrafluoroethylene layer (9) longitudinally wraps the outer surface of the cable core (8), and the second polytetrafluoroethylene layer (9) is connected to the first, second, third and fourth symmetrical insulated wires The gap between the pairs (3, 4, 5, 6) is filled with several cotton yarns (10); A cotton fiber thread (17) is wound on the outer surface of the second polytetrafluoroethylene layer (9) to form a buffer sliding layer (12), and the winding direction of the cotton fiber thread (17) is the same as that of the first, second, third and The twisting direction of the fourth symmetrical insulated wire pair (3, 4, 5, 6) is opposite; Several metal wires (13) are wound side by side on the outer surface of the buffer sliding layer (12) to form a metal shielding layer (14), and the outer surface of the metal wires (13) in the metal shielding layer (14) is wrapped with a third A polytetrafluoroethylene tape (15), the winding direction of the third polytetrafluoroethylene tape (15) is opposite to the winding direction of the cotton fiber thread (17); An outer sheath layer (16) covers the outer surface of the third polytetrafluoroethylene layer (15).