A cable

Abstract

The present invention discloses a cable, which relates to the field of cable technology, to solve the problem of external high-frequency electromagnetic interference signals when the cable is long. A cable includes: a first cable core and a second cable core distributed in sequence from the inside to the outside, the second cable core is coated on the outer surface of the first cable core, the resistance of the first cable core is less than the resistance of the second cable core, and the surface of the second cable core away from the first cable core is provided with grooves distributed at intervals along the circumferential direction, and the extension direction of the grooves is parallel to the axial direction of the cable core. Since the resistance of the second cable core is greater than the resistance of the first cable core, the second cable core coated on the outside of the first cable core can suppress the flow of high-frequency current. At the same time, the grooves on the second cable core limit high-frequency eddy currents, effectively avoiding interference from high-frequency electronic signals.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a cable. Background Art

[0002] At present, the communication frequency is 100KHz. In order to maintain the integrity of the waveform, it is necessary to cover the frequency of 10~1000KHz. The existing cable core usually uses a copper core, which can pass signals of all frequencies. When the frequency increases, due to the skin effect, the high-frequency signal will be concentrated on the surface of the cable core. In the existing cable core used for high-frequency signals, the current is mainly in the outer layer of the cable core. In order to reduce costs, a low-cost iron core is usually used in the center of the cable core, and only a layer of high-conductivity copper coating is coated on the outside. When the cable is long, high-frequency interference signals such as external electromagnetic interference and internal ringing will appear. At the same time, because it is powered by the power grid, it will also be interfered by low-frequency signals of 50Hz. Summary of the invention

[0003] An object of the present invention is to provide a cable for suppressing signal interference.

[0004] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a cable, comprising: a first cable core and a second cable core distributed in sequence from the inside to the outside, the second cable core is coated on the outer surface of the first cable core, the resistance of the first cable core is smaller than the resistance of the second cable core, and the surface of the second cable core away from the first cable core is provided with grooves distributed at intervals along the circumferential direction, and the extension direction of the grooves is parallel to the axial direction of the cable core.

[0005] Optionally, in the above cable, the cross-sectional shape of the groove includes a rectangle, a triangle or a hemisphere.

[0006] Optionally, in the above cable, the cross-sectional shape of the first cable core is circular, and both the first cable core and the second cable core can conduct the low-frequency signal f 1 and / or intermediate frequency signal f 2 , and the second cable core is used to suppress high-frequency signals f 3 , the material radius R of the first cable core and the material thickness D of the second cable core 2 The following conditions are met:

[0007] ;

[0008] ;

[0009] ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core, is the resistivity of the second cable core.

[0010] Optionally, in the above cable, the cross-sectional shape of the first cable core is a ring, and both the first cable core and the second cable core can conduct the intermediate frequency signal f 2 , and the second cable core is used to suppress high-frequency signals f 3 , the material thickness D of the first cable core 1 and the material thickness D of the second cable core 2 The following conditions are met:

[0011] ;

[0012] ;

[0013] ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core, is the resistivity of the second cable core.

[0014] Optionally, in the above cable, a ratio of a cross-sectional width a of the groove to a groove depth h of the groove is 0.9-1.1.

[0015] Optionally, in the above cable, the groove depth ,in, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core and the second cable core.

[0016] Optionally, in the above cable, a ratio of a length b of the groove extending along the axial direction of the first cable core to a cross-sectional width a of the groove is 8-12.

[0017] Optionally, in the above cable, the angle between two adjacent grooves and the first cable core on the same cross section is 20°~45°.

[0018] Optionally, in the above cable, the material of the first cable core includes silver, copper, gold or aluminum.

[0019] Optionally, in the above cable, the material of the second cable core includes nickel-chromium alloy, iron-chromium-aluminum alloy or aluminum-nickel-iron alloy.

[0020] Optionally, in the above cable, the first cable core and the second cable core are an integrated structure;

[0021] Alternatively, the first cable core and the second cable core are welded.

[0022] Compared with the prior art, when the above technical solution is adopted, since the resistance of the second cable core is greater than the resistance of the first cable core, the second cable core wrapped around the outside of the first cable core can suppress the flow of high-frequency current. At the same time, when the external high-frequency electromagnetic field penetrates the cable, it will cause eddy currents on the surface of the cable, interfering with the normal communication signal. The grooves on the second cable core prevent the eddy currents from forming a loop on the surface of the second cable core, further limiting the high-frequency eddy currents. Compared with the traditional single-core cable passing through non-magnetic pipes to reduce eddy currents, the first cable core and the second cable core in the present application are both made of metal and the two layers of metal are in direct contact and conduction. The interference of high-frequency electronic signals is effectively avoided through different resistivities and different radial thicknesses of the two. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 This is a schematic structural diagram of a cable provided in an embodiment of the present invention, in which the cross-sectional shape of the first cable core is circular;

[0025] Figure 2 for Figure 1 A cross-sectional view of a

[0026] Figure 3 This is a schematic structural diagram of a cable provided in an embodiment of the present invention, in which the cross-sectional shape of the first cable core is a circular ring;

[0027] Figure 4 for Figure 3 Cross-sectional view of .

[0028] Reference numerals:

[0029] 1-first cable core; 2-second cable core; 3-groove. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0033] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] like Figure 1-Figure 4 As shown, a cable provided by an embodiment of the present invention includes: a first cable core 1 and a second cable core 2.

[0036] Among them, the first cable core 1 and the second cable core 2 are distributed in sequence from the inside to the outside, the second cable core 2 is coated on the outer surface of the first cable core 1, the resistance of the first cable core 1 is smaller than the resistance of the second cable core 2, and the surface of the second cable core 2 away from the first cable core 1 is provided with grooves 3 distributed at intervals along the circumferential direction, and the extension direction of the grooves 3 is parallel to the axial direction of the cable core.

[0037] When implementing it, Figure 1As shown, since the resistance of the second cable core 2 is greater than that of the first cable core 1, the second cable core 2 wrapped around the outside of the first cable core 1 can suppress the flow of high-frequency current. At the same time, when the external high-frequency electromagnetic field penetrates the cable, it will cause eddy currents on the surface of the cable, interfering with the normal communication signal. The groove 3 on the second cable core 2 prevents the eddy currents from forming a loop on the surface of the second cable core 2, further limiting the high-frequency eddy currents. Compared with the traditional single-core cable passing through a non-magnetic pipe to reduce the eddy current, the first cable core 1 and the second cable core 2 in the present application are both made of metal and the two layers of metal are in direct contact and conduction. Through different resistivities and different thicknesses along the radial direction, and the eddy current penetration depth in the metal conductor is usually The groove 3 can prevent the eddy current from forming a complete loop on the surface of the second cable core 2, effectively avoiding the interference of high-frequency electronic signals.

[0038] Specifically, in this embodiment, the cross-sectional shape of the groove 3 includes a rectangle, a triangle or a hemisphere. Of course, the cross-sectional shape of the groove 3 can also be other shapes, which are not specifically limited here, as long as the groove 3 can limit the high-frequency eddy current.

[0039] like Figure 1 As shown, specifically, in this embodiment, the cross-sectional shape of the first cable core 1 is circular, and both the first cable core 1 and the second cable core 2 can conduct the low-frequency signal f 1 and / or intermediate frequency signal f 2 , and the second cable core 2 is used to suppress the high-frequency signal f 3 , the material radius R of the first cable core 1 and the material thickness D of the second cable core 2 2 The following conditions are met:

[0040] ;

[0041] ;

[0042] ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core 1, is the resistivity of the second cable core 2. Where, ; Different materials have different magnetic permeabilities. Since the first cable core 1 and the second cable core 2 are made of metal conductors, , and then according to the imported low-frequency signal f 1 and / or intermediate frequency signal f 2 , the suppressed high frequency current f 3 And the resistivity of the first cable core 1 and the resistivity of the second cable core 2 Substituting the above three formulas respectively, the material radius R of the first cable core 1 and the material thickness D of the second cable core 2 can be calculated. 2 , when the material thickness of the first cable core 1 and the second cable core 2 meets the above requirements, the second cable core 2 located in the outer layer can suppress the passage of high-frequency current, and the first cable core 1 located in the center can only conduct medium-frequency current or conduct low-frequency current, or the first cable core 1 located in the center can conduct medium-frequency current and low-frequency current at the same time, so as to achieve the cable's suppression of interference with high-frequency electronic signals. Among them, the cross-sectional shape of the first cable core 1 can be circular, square or other shapes, which are not specifically limited here. The preferred solution is that the cross-sectional shape of the first cable core 1 is circular. When the first cable core 1 does not have a hollow structure, a material with a larger impedance can be selected to reduce the interference caused by low-frequency signals (such as 50Hz signals brought by the power grid).

[0043] It should be noted that according to It can be seen that the signal transmitted in the cable gradually distributes to the outer surface of the cable as the frequency increases (i.e., the second cable core 2 is distributed on the side away from the first cable core 1). At this time, when high frequency is passed, the depth distribution is shallow, i.e., on the outer surface of the second cable core; when medium frequency is passed, the distribution depth is moderate, i.e., on the area on the first cable core close to the second cable core; when low frequency is passed, the distribution depth is deep, i.e., located in the center area of ​​the first cable core. Similarly, low impedance is beneficial to the passage of signals, and high impedance inhibits the passage of signals. When the outer layer impedance of the cable is high, high frequencies are inhibited; when the middle layer impedance of the cable is low, medium frequencies are conducted; and when the inner layer impedance of the cable is high, low frequencies are inhibited.

[0044] like Figure 2 As shown, specifically, in this embodiment, the cross-sectional shape of the first cable core 1 is a ring, and both the first cable core 1 and the second cable core 2 can conduct the intermediate frequency signal f 2 , and the second cable core 2 is used to suppress the high-frequency signal f 3 , the material thickness D of the first cable core 1 1 and the material thickness D of the second cable core 2 2 The following conditions are met:

[0045] ;

[0046] ;

[0047] ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core 1, is the resistivity of the second cable core 2. Where, ; Different materials have different magnetic permeabilities. Since the first cable core 1 and the second cable core 2 are made of metal conductors, , and then according to the imported intermediate frequency signal f 2 And the resistivity of the first cable core 1 and the resistivity of the second cable core 2 Substituting the above three formulas respectively, the material radius R of the first cable core 1 and the material thickness D of the second cable core 2 can be calculated. 2 , when the material thickness of the first cable core 1 and the second cable core 2 meets the above requirements, the second cable core 2 located at the outer layer can suppress the passage of high-frequency current, and the first cable core 1 located in the center can only conduct medium-frequency current or low-frequency current, or the first cable core 1 located in the center can conduct medium-frequency current and low-frequency current at the same time, so as to achieve the cable's suppression of high-frequency electronic signal interference. Among them, the inside of the ring is hollow, and since the impedance of the air is much greater than the impedance of the first cable core 1, according to the formula It can be seen that the higher the impedance of the inner layer of the cable, the more complete the suppression of low frequencies can be achieved.

[0048] like Figure 2 and Figure 4 As shown, specifically, in this embodiment, the ratio of the cross-sectional width a of the groove 3 to the groove depth h of the groove 3 is 0.9 to 1.1. The ratio of the cross-sectional width a of the groove 3 to the groove depth h of the groove 3 is a:h, wherein the ratio of the two can be 0.9, 1.0, 1.05, 1.1, etc., and the ratio between the cross-sectional width a of the groove 3 and the groove depth h of the groove 3 is not specifically limited.

[0049] like Figure 2 and Figure 4 As shown, specifically, in this embodiment, the groove depth ,in, is the relative magnetic permeability of the conductor, When the groove depth h of the groove 3 satisfies the requirement of being greater than the eddy current depth h, the penetration depth of the eddy current in the metal conductor cannot reach the bottom surface of the groove 3, so that a circulation cannot be formed on the surface of the second cable core. At this time, the eddy current can be completely blocked.

[0050] like Figure 1 and Figure 3 As shown, specifically, in this embodiment, the ratio of the length b of the groove 3 extending along the axial direction of the first cable core 1 to the cross-sectional width a of the groove 3 is 8 to 12. The ratio of the length b of the groove 3 extending along the axial direction of the first cable core 1 to the cross-sectional width a of the groove 3 is b:a, wherein the ratio of the two can be 8, 9.2, 10, 11.5, 12, etc., and the ratio between the length b of the groove 3 extending along the axial direction of the first cable core 1 and the cross-sectional width a of the groove 3 is not specifically limited.

[0051] like Figure 2 and Figure 4As shown, specifically, in this embodiment, the angle between two adjacent grooves 3 and the first cable core 1 on the same cross section includes 20°~45°. Among them, the angle θ between two adjacent grooves 3 and the first cable core 1 can be 20°, 25°, 30°, 36°, 45°, etc., and the angle θ between two adjacent grooves 3 and the first cable core 1 is not specifically limited, as long as the multiple grooves 3 are evenly arranged along the circumferential direction.

[0052] Specifically, in this embodiment, the material of the first cable core 1 includes silver, copper, gold or aluminum. The material of the first cable core 1 can also be other low-resistance metals, which are not specifically limited here, as long as the first cable core 1 can conduct medium-frequency current and / or low-frequency current.

[0053] Specifically, in this embodiment, the material of the second cable core 2 includes nickel-chromium alloy, iron-chromium-aluminum alloy or aluminum-nickel-iron alloy. The material of the second cable core 2 can also be other high-resistance metals, which are not specifically limited here, as long as the resistance of the second cable core 2 is greater than the resistance of the first cable core 1 and can suppress high-frequency current.

[0054] Specifically, in this embodiment, the first cable core 1 and the second cable core 2 are an integrated structure; or, the first cable core 1 and the second cable core 2 are welded. Of course, the connection between the first cable core 1 and the second cable core 2 can also be achieved by bonding or other methods that can achieve fixed connection, which is not specifically limited here, as long as the two layers of metal materials of the first cable core 1 and the second cable core 2 are in direct contact and conduction.

[0055] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A cable, characterized in that: include: A first cable core and a second cable core are sequentially distributed from the inside to the outside, the second cable core is coated on the outer surface of the first cable core, the resistance of the first cable core is smaller than the resistance of the second cable core, and the surface of the second cable core away from the first cable core is provided with grooves spaced apart in the circumferential direction, and the extension direction of the grooves is parallel to the axial direction of the cable core; The material of the first cable core includes silver, copper, gold or aluminum, and the material of the second cable core includes nickel-chromium alloy, iron-chromium-aluminum alloy or aluminum-nickel-iron alloy; The cross-sectional shape of the first cable core is circular, the first cable core and the second cable core can both conduct low-frequency signals f1 and / or medium-frequency signals f2, and the second cable core is used to suppress high-frequency signals f3, and the material radius R of the first cable core and the material thickness D2 of the second cable core meet the following conditions: ； ； ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core, is the resistivity of the second cable core; Alternatively, the cross-sectional shape of the first cable core is a ring, the first cable core and the second cable core can both conduct the intermediate frequency signal f2, and the second cable core is used to suppress the high frequency signal f3, and the material thickness D1 of the first cable core and the material thickness D2 of the second cable core meet the following conditions: ； ； ,in, is the magnetic permeability constant, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core, is the resistivity of the second cable core.

2. The cable according to claim 1, characterized in that: The cross-sectional shape of the groove includes a rectangle, a triangle or a hemisphere.

3. The cable according to claim 1, characterized in that: The ratio of the cross-sectional width a of the groove to the groove depth h of the groove is 0.9-1.

1.

4. The cable according to claim 3, characterized in that: The groove depth ,in, is the relative magnetic permeability of the conductor, is the resistivity of the first cable core and the second cable core.

5. The cable according to claim 3, characterized in that: The ratio of the length b of the groove extending along the axial direction of the first cable core to the cross-sectional width a of the groove is 8-12.

6. The cable according to claim 3, characterized in that: The included angle between two adjacent grooves and the first cable core on the same cross section is 20° to 45°.

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