Composite shielded temperature resistant cable for inductive sensors

Abstract

The utility model relates to wire and cable technical field, more particularly to the composite shielding signal temperature resistant cable for inductor, include: a plurality of mutually twisted wire core, each wire core includes a pair of twisted pair line structure and the shielding layer that covers outside the twisted pair line structure, total shielding layer, cover in a plurality of mutually twisted outside, total shielding layer includes first shielding layer and second shielding layer, sheath layer, cover the outer wall of total shielding layer, the utility model discloses a composite shielding structure that adopts PETT base aluminium foil tape and variable pitch ratio spiral braid copper wire are combined, effectively disperses the thermal stress that produces because of temperature cycle change, and variable pitch ratio design avoids stress concentration, prevents the metal fatigue fracture that traditional single pitch ratio braiding layer appears easily in fixed node, makes total shielding layer still can keep structural integrity under high temperature, effectively prevents the electromagnetic interference that leads to because of shielding layer cracking.

Description

Technical Field

[0001] This utility model relates to the field of wire and cable technology, and more specifically to composite shielded signal heat-resistant cable for sensors. Background Technology

[0002] In the field of high-temperature industrial sensing, such as monitoring of aero-engine test benches, internal sensing of nuclear reactors, continuous temperature measurement of metallurgical furnaces, and high-temperature chemical reactors, high-temperature resistant signal cables are used to transmit sensing signals. These signal cables need to stably transmit microvolt-level electrical signals in harsh environments ranging from 200 to 1000°C. These cables are typically composed of a conductor, an inorganic insulation layer, a shielding layer, and an outer sheath.

[0003] However, after repeated and drastic temperature changes, cracks often appear at the longitudinal overlap of the metal wrapping tape of the cable shield, resulting in physical separation. When such cracks appear in the shield, the weak electrical signal at the microvolt level transmitted by the sensor will be subject to severe external electromagnetic interference, leading to distortion of monitoring data or complete loss of signal. Utility Model Content

[0004] To address the technical problems existing in high-temperature resistant signal cables in the prior art, this utility model proposes a composite shielded high-temperature resistant signal cable for sensors, comprising:

[0005] Multiple twisted wire cores, each wire core including a pair of twisted wire structures and a shielding layer covering the twisted wire structures;

[0006] The overall shielding layer covers the multiple intertwined strands, and the overall shielding layer includes a first shielding layer and a second shielding layer;

[0007] Sheath layer, covering the outer wall of the total shielding layer;

[0008] The first shielding layer is a PETT-based aluminum foil wrapping structure layer, and the PETT-based aluminum foil wrapping structure layer has a PETT-based aluminum foil wrapping overlap rate of 40-50%. The second shielding layer is a copper wire braided structure layer, and the copper wire braided structure layer includes a variable pitch ratio spiral braided copper wire structure layer.

[0009] The variable pitch ratio spiral braided copper wire structure layer includes a first pitch ratio section and a second pitch ratio section along the cable axis, wherein the braiding pitch ratio of the copper wire in the second pitch ratio section is greater than that in the first pitch ratio section.

[0010] Preferably, the braiding pitch ratio of the variable pitch ratio spiral braided copper wire structure layer varies periodically along the cable axis.

[0011] Preferably, the lengths of the first and second diameter ratio segments are the same.

[0012] Preferably, the braiding pitch ratio of the copper wires in the copper wire braided structure layer is 8 to 12.

[0013] Preferably, the twisted pair structure includes two twisted conductors, each conductor including a conductor and an insulating layer, wherein the insulating layer is configured to have a temperature coefficient gradient distribution from the inner layer to the outer layer.

[0014] Preferably, the insulating layer includes an inner insulating layer, a middle insulating layer, and an outer insulating layer. The inner insulating layer includes a mica tape wrapping layer, the middle insulating layer includes a polyimide composite tape longitudinal wrapping layer, and the outer insulating layer includes a ceramicized silicone rubber insulating layer.

[0015] Preferably, the shielding layer includes an inner annealed copper foil longitudinally wrapped shielding layer and an outer glass fiber cloth longitudinally wrapped reinforcing layer. The high CTE soft metal foil expands first when heated, and its flexibility can fit well with the inner insulating layer, providing basic and continuous shielding. The low CTE high-temperature alloy acts as a mechanical skeleton, and its expansion is less than that of the inner layer, thereby forming a mild clamping effect on the inner layer at high temperature, preventing the inner layer from expanding excessively or wrinkling.

[0016] Preferably, the sheath layer includes a ceramicized silicone rubber sheath layer and a carbon fiber woven sheath layer, with the carbon fiber woven sheath layer located on the outer layer of the ceramicized silicone rubber sheath layer.

[0017] Compared with existing technologies, the significant advantages of the composite shielded signal heat-resistant cable for sensors of this invention are:

[0018] This invention relates to a composite shielded signal heat-resistant cable for sensors. The composite shielding structure, combining PETT-based aluminum foil wrapping with variable-ratio spiral braided copper wire, effectively disperses thermal stress caused by temperature cycling. The variable-ratio design of the shielding layer avoids stress concentration and prevents metal fatigue fractures that are common at fixed nodes in traditional single-ratio braided layers. The 40%–50% overlap of the aluminum foil wrapping layer ensures shielding continuity while providing sufficient deformation redundancy, allowing the overall shielding layer to maintain structural integrity at high temperatures and effectively preventing electromagnetic interference caused by shielding layer cracking. Attached Figure Description

[0019] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of the composite shielded signal heat-resistant cable for sensors shown in this utility model.

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of the composite shielded signal heat-resistant cable for sensors shown in this utility model.

[0022] Figure 3 This is a schematic diagram of the conductor core shown in this utility model.

[0023] Figure 4 This is a schematic diagram of the overall shielding layer shown in this utility model. Detailed Implementation

[0024] To better understand the technical content of this utility model, specific embodiments are provided below in conjunction with the accompanying drawings.

[0025] Combination Figure 1 and Figure 2 As shown, the composite shielded signal heat-resistant cable for sensors according to an embodiment of the present invention includes multiple twisted cores 10, a total shielding layer 20 located outside the twisted cores 10, and a sheath layer 30.

[0026] The wire core 10 is usually designed with 2 to 8 strands, such as Figure 1 and Figure 2 The example shown uses four wires, coiled into a perfectly round cross-section. The choice of the number of twisted cores (10 strands) depends on the number of channels for sensor signal transmission, cable flexibility, and electromagnetic compatibility requirements. Twisting multiple cores helps to counteract external electromagnetic interference and improve signal transmission stability.

[0027] Each wire core 10 includes a pair of twisted-pair structures 11 and a shielding layer 12 covering the twisted-pair structures.

[0028] Furthermore, the twisted pair structure 11 includes two twisted conductors, each conductor including a conductor 111 and an insulation layer 112, the insulation layer 112 being configured to have a temperature coefficient gradient distribution from the inner layer to the outer layer.

[0029] By setting the insulation layer 112 to have a gradient distribution of temperature coefficient, it is beneficial to buffer the difference in thermal expansion between material layers with different temperature coefficients, and avoid interlayer peeling or cracking caused by sudden temperature changes.

[0030] Preferably, the inner insulation layer focuses more on insulation performance and thermal stability, while the outer insulation layer takes into account mechanical strength and temperature resistance. In this way, the gradient structure can maintain the integrity and electrical performance of the insulation layer 112 in high-temperature environments.

[0031] In an optional embodiment, combined with Figure 3As shown, the insulating layer 112 includes an inner insulating layer 112a, a middle insulating layer 112b, and an outer insulating layer 112c. The inner insulating layer 112a includes a mica tape wrapping layer, the middle insulating layer 112b includes a polyimide composite tape longitudinal wrapping layer, and the outer insulating layer 112c includes a ceramicized silicone rubber insulating layer.

[0032] In the specific embodiments described above, the mica tape wrapping layer possesses excellent high-temperature insulation performance and thermal stability, as well as a high fire resistance rating. The polyimide composite tape longitudinal wrapping layer exhibits good mechanical strength and chemical resistance, enhancing the overall structural stability of the insulation layer. The ceramicized silicone rubber insulation layer can be ceramicized at high temperatures to form a hard protective layer, further improving fire resistance and insulation performance.

[0033] In this way, by designing a gradient temperature coefficient, high temperatures are addressed layer by layer, effectively buffering thermal stress and preventing delamination or cracking of the insulation layer due to thermal expansion mismatch, thus ensuring long-term insulation reliability under extreme temperatures of 200 to 1000°C.

[0034] In other embodiments, the insulating layer 112 may also be a three-layer structure composed of mica tape, polytetrafluoroethylene composite tape and ceramicized silicone rubber.

[0035] Furthermore, the shielding layer 12 includes an inner annealed copper foil longitudinally wrapped shielding layer and an outer glass fiber cloth longitudinally wrapped reinforcing layer.

[0036] Specifically, the annealed soft copper foil has good ductility and adhesion. When heated, it can expand synchronously with the insulation layer to maintain the continuity of the shielding. The longitudinally wrapped glass fiber cloth reinforcement layer has a low coefficient of thermal expansion and high mechanical strength. At high temperatures, it forms a clamping effect on the inner layer to prevent excessive expansion or wrinkling of the inner layer and improve the overall structural stability of the shielding layer.

[0037] Among them, the high CTE soft metal foil expands first when heated, and its flexibility allows it to fit well with the inner insulation layer, providing basic and continuous shielding. The low CTE high-temperature alloy acts as a mechanical skeleton, and its expansion is less than that of the inner layer, thus forming a mild clamping effect on the inner layer at high temperatures, preventing the inner layer from expanding excessively or wrinkling.

[0038] In this way, by utilizing the expansion and adhesion effect of the inner high CTE soft metal foil and the clamping effect of the outer low CTE material, they work together at high temperatures to ensure the continuity of shielding and prevent the shielding layer from wrinkling or loosening, thus ensuring the stable transmission of microvolt-level weak signals in high-temperature environments.

[0039] Furthermore, the total shielding layer 20 covers the multiple twisted wire cores 10, and the total shielding layer 20 includes a first shielding layer 21 and a second shielding layer 22.

[0040] The first shielding layer 21 is a PETT-based aluminum foil wrapping structure layer with a PETT-based aluminum foil wrapping overlap rate of 40-50%. The second shielding layer 22 is a copper wire braided structure layer, which includes a variable diameter spiral braided copper wire structure layer.

[0041] Thus, the first shielding layer 21 provides 100% coverage of static magnetic field shielding, with an overlap rate of 40-50% to ensure longitudinal electrical continuity, while also possessing a certain degree of flexibility and temperature resistance. The second shielding layer 22 provides dynamic electromagnetic shielding, and the variable pitch ratio design can disperse structural stress, avoid periodic fatigue fracture caused by a single pitch ratio, and improve vibration and thermal cycling resistance.

[0042] The first diameter-ratio segment 221 and the second diameter-ratio segment 222 have the same length.

[0043] Furthermore, the braided pitch ratio of the variable pitch ratio spiral braided copper wire structural layer varies periodically along the cable axis. In particular, it is periodically braided using first pitch ratio segments 221 and second pitch ratio segments 222 of the same length. That is, after continuously wrapping the PETT-based aluminum foil tape around the core 10 to form the structural layer, the first pitch ratio segments 221 and second pitch ratio segments 222 of the same length are periodically and continuously braided as a group.

[0044] In an optional embodiment, combined with Figure 4 As shown, the variable pitch ratio spiral braided copper wire structure layer includes a first pitch ratio section 221 and a second pitch ratio section 222 along the cable axis, wherein the braiding pitch ratio of the copper wire in the second pitch ratio section 222 is greater than the braiding pitch ratio of the copper wire in the first pitch ratio section 221.

[0045] Furthermore, the braiding pitch ratio of the copper wires in the copper wire braided structure layer is preferably 8 to 12.

[0046] In a specific embodiment, the braided section diameter ratio of the copper wire in the first section diameter ratio segment 221 is 12, and the braided section diameter ratio of the copper wire in the second section diameter ratio segment 222 is 8.

[0047] In this way, by varying the pitch, the copper wire has room to deform under changing temperature conditions, and gradually forms a smooth and gradual pitch, thus avoiding stress concentration.

[0048] Furthermore, the sheath layer 30 covers the outer wall of the total shielding layer 20. The sheath layer 30 includes a ceramicized silicone rubber sheath layer 31 and a carbon fiber braided sheath layer 32, with the carbon fiber braided sheath layer 32 located outside the ceramicized silicone rubber sheath layer 31.

[0049] Thus, the ceramicized silicone rubber sheath layer 31 forms a hard protective shell at high temperature, possessing excellent fire resistance, heat insulation and insulation properties. The outer carbon fiber woven sheath layer 32 provides high-strength, wear-resistant and tensile-resistant mechanical protection, while also possessing a certain degree of conductivity, which can assist in static electricity discharge and electromagnetic shielding.

[0050] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. A composite shielded signal heat-resistant cable for sensors, characterized in that, include: Multiple twisted wire cores (10), each wire core (10) includes a pair of twisted wire structures (11) and a shielding layer (12) covering the twisted wire structures; the shielding layer (12) includes an inner annealed copper foil longitudinally wrapped shielding layer and an outer glass fiber cloth longitudinally wrapped reinforcing layer. A total shielding layer (20) covers the multiple intertwined strands of the (10), and the total shielding layer (20) includes a first shielding layer (21) and a second shielding layer (22); A sheath layer (30) covers the outer wall of the total shielding layer (20); The first shielding layer (21) is a PETT-based aluminum foil wrapping structure layer, and the PETT-based aluminum foil wrapping structure layer has a PETT-based aluminum foil wrapping overlap rate of 40-50%. The second shielding layer (22) is a copper wire braiding structure layer, and the copper wire braiding structure layer includes a variable diameter ratio spiral braided copper wire structure layer. The variable pitch ratio spiral braided copper wire structure layer includes a first pitch ratio section (221) and a second pitch ratio section (222) along the cable axis, wherein the braiding pitch ratio of the copper wire in the second pitch ratio section (222) is greater than the braiding pitch ratio of the copper wire in the first pitch ratio section (221).

2. The composite shielded signal heat-resistant cable for sensors according to claim 1, characterized in that, The braided section ratio of the variable section ratio spiral braided copper wire structure layer varies periodically along the cable axis.

3. The composite shielded signal heat-resistant cable for sensors according to claim 1, characterized in that, The length of the first diameter ratio segment (221) is the same as the length of the second diameter ratio segment (222).

4. The composite shielded signal heat-resistant cable for sensors according to any one of claims 1-3, characterized in that, The braiding pitch ratio of the copper wires in the variable pitch ratio spiral braided copper wire structure layer is 8 to 12.

5. The composite shielded signal heat-resistant cable for sensors according to claim 4, characterized in that, In the variable pitch ratio spiral braided copper wire structure layer, the braiding pitch ratio of the copper wire in the first pitch ratio section (221) is 12, and the braiding pitch ratio of the copper wire in the second pitch ratio section (222) is 8.

6. The composite shielded signal heat-resistant cable for sensors according to claim 1, characterized in that, The twisted pair structure (11) includes two twisted conductors, each conductor including a conductor (111) and an insulation layer (112). The insulation layer (112) is configured to have a gradient temperature coefficient from the inner layer to the outer layer to avoid delamination or cracking of the insulation layer due to thermal expansion mismatch.

7. The composite shielded signal heat-resistant cable for sensors according to claim 6, characterized in that, The insulating layer (112) includes an inner insulating layer (112a), a middle insulating layer (112b) and an outer insulating layer (112c). The inner insulating layer (112a) includes a mica tape wrapping layer, and the middle insulating layer (112b) includes a polyimide composite tape longitudinal wrapping layer.

8. The composite shielded signal heat-resistant cable for sensors according to claim 7, characterized in that, The outer insulating layer (112c) includes a ceramicized silicone rubber insulating layer.

9. The composite shielded signal heat-resistant cable for sensors according to claim 7, characterized in that, The insulating layer (112) is a three-layer structure composed of mica tape, polytetrafluoroethylene composite tape, and ceramicized silicone rubber.

10. The composite shielded signal heat-resistant cable for sensors according to claim 1, characterized in that, The sheath layer (30) includes a ceramicized silicone rubber sheath layer (31) and a carbon fiber braided sheath layer (32), with the carbon fiber braided sheath layer (32) located on the outer layer of the ceramicized silicone rubber sheath layer (31).

Images