Power transmission wire for a robot resistant to twisting and swinging and method of manufacturing the same
By designing composite stress conductors, gradient sliding insulation layers, and spiral reinforced sheaths, and combining them with fiber optic sensing monitoring, the problems of conductor breakage and insulation cracking in robot cables under high-frequency torsion and multi-axis oscillation have been solved. This has enabled self-repair and condition monitoring, meeting the long-cycle and high-reliability application requirements of high-end robots.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FAR EAST CABLE
- Filing Date
- 2026-05-13
- Publication Date
- 2026-06-09
AI Technical Summary
Existing robot cables are prone to problems such as conductor breakage, sudden increase in resistance, insulation cracking, and short circuit failure under high-frequency torsion and multi-axis swing conditions. Furthermore, they cannot achieve conductor self-repair and condition monitoring, making it difficult to meet the application requirements of high-end robots for long cycles, high reliability, and precision.
It adopts an inside-out structural design, including a composite stress conductor, a gradient sliding insulation layer, and a spiral reinforcement sheath. The internal fiber optic sensing unit is integrated, and self-healing is achieved by using a hollow spiral magnesium-aluminum alloy skeleton, ultra-fine silver-plated copper wire, and gallium-based liquid metal. The PTFE micro-nano texture and graphene TPV stress buffer layer reduce friction loss. The outer nickel-plated LCP spiral reinforcement belt and elastic damping wire disperse torsional stress, and the outer layer is covered with a wear-resistant ceramic micro-coating, integrating fiber optic sensing and monitoring.
It achieves the self-healing capability of the conductor, increases the torsional fatigue life to more than 15 million cycles, increases the dynamic crack life of the insulation layer by 3 times, reduces the weight by 25%, adapts to complex industrial environments, and realizes the integration of conductivity and monitoring.
Smart Images
Figure CN122177553A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of special cables for robots, and in particular to a torsion-resistant and sway-resistant power transmission wire for robots and its preparation method. Background Technology
[0002] The rapid development of collaborative robots, AGV / AMR mobile robots, surgical robots, and industrial articulated robots has placed stringent demands on the dynamic lifespan of power transmission cables used in joints, cable chains, and end effectors, requiring over a million torsional cycles without cracking or breakage. Traditional robot cables, using bare copper stranded wires as conductors and covered with thermoplastic elastomers such as TPU and PVC, are prone to conductor breakage, sudden increases in resistance, insulation cracking, and short-circuit failure under high-frequency torsion exceeding ±180° and multi-axis oscillation conditions.
[0003] Existing improvement solutions optimize performance by increasing the number of conductor strands, using ultra-fine copper wires, and improving insulation flexibility. While these solutions slightly improve dynamic performance, they suffer from drawbacks such as increased outer diameter, excessive weight, and conflict with the goal of making robots lightweight. Furthermore, they cannot achieve conductor breakage self-repair, uniform distribution of torsional stress, or real-time monitoring of operating status, making it difficult to meet the application requirements of high-end robots for long cycles, high reliability, and precision.
[0004] Based on this, the present invention addresses the technical pain points of conductor breakage, insulation cracking, torsion kinking, and unpredictable state by starting from four dimensions: structural innovation, material composite, functional integration, and process optimization. It provides a precision lightweight power transmission conductor that is anti-torsion, resistant to swaying, self-healing, and monitorable. Summary of the Invention
[0005] The technical problem to be solved by this invention is that conductors are prone to breakage, insulation is prone to cracking, torsion is prone to kinking, and the state is unpredictable.
[0006] The technical solution adopted by this invention to solve its technical problem is: a torsion-resistant and sway-resistant power transmission wire for robots, comprising, from the inside out, a composite stress conductor, a gradient sliding insulation layer, and a spiral reinforcing sheath; the composite stress conductor integrates an optical fiber sensing unit; the composite stress conductor comprises a hollow spiral magnesium-aluminum alloy skeleton, ultra-fine silver-plated copper wire, and gallium-based liquid metal doped with carbon nanotubes; the gradient sliding insulation layer has a three-layer gradient structure; and the spiral reinforcing sheath is embedded with a nickel-plated spiral reinforcing strip and an elastic damping wire.
[0007] The innermost layer of the composite stress conductor is provided with a polyimide buffer liner, the hollow spiral magnesium-aluminum alloy skeleton is located outside the buffer liner, the ultrafine silver-plated copper wire is spirally twisted along the skeleton, and the gallium-based liquid metal is vacuum-filled in the gaps between the copper wires.
[0008] The gradient sliding insulation layer consists of, from the inside out, a PTFE micro-nano textured super-slippery inner layer, a graphene TPV stress buffer layer, and an irradiated cross-linked TPU tear-resistant outer layer, with a silane coupling agent transition layer between the layers.
[0009] The PTFE micro-nano textured super-smooth inner layer has a micro-nano pit array on its surface, a friction coefficient ≤0.05, and a thickness of 0.03~0.08mm; the graphene TPV stress buffer layer has a Shore hardness of 70~85A and a thickness of 0.2~0.5mm.
[0010] The spiral reinforced sheath has a nickel-plated LCP spiral reinforced strip inside, which is double-wound in both directions with a spiral angle of 35°~55° and a winding pitch of 5~15 times the outer diameter of the sheath.
[0011] The outer surface of the spiral reinforced sheath is covered with a wear-resistant ceramic micro-coating, and the sheath has an oval-shaped cross-section.
[0012] The ultrafine silver-plated copper wire has a diameter of 0.03~0.05mm, and the multi-walled carbon nanotube doping content in the gallium-based liquid metal is 1~3wt%.
[0013] A method for preparing a torsion-resistant and sway-resistant power transmission wire for robots includes the following steps: S1 is used to prepare a hollow spiral magnesium-aluminum alloy skeleton with an inner wall composite polyimide buffer liner; S2 involves spirally twisting ultra-fine silver-plated copper wires along a skeleton and vacuum-infusing gallium-based liquid metal doped with carbon nanotubes. S3 uses plasma etching to form a micro-nano texture in the inner layer of PTFE, and co-extrudes it to form a gradient sliding insulating layer. S4 is formed by double-wound nickel-plated LCP reinforcing strip and elastic damping wire, and co-extruded into a spiral reinforcing sheath. The S5 integrated fiber optic sensing unit is used to obtain the finished conductor through microwave cross-linking.
[0014] The liquid metal injection process is vacuum injection, with a vacuum degree ≤ -0.095MPa and an injection temperature of 40~60℃.
[0015] After molding, the sheath is cross-linked by microwave irradiation, with a cross-linking degree of 60%~85%.
[0016] The beneficial effects of this invention are: (1) The hollow spiral magnesium-aluminum alloy skeleton of the present invention provides stable mechanical support for the conductor. The gallium-based liquid metal doped with carbon nanotubes fills the gaps between the copper wires. When the copper wire breaks locally, a bypass conductive channel can be quickly formed to achieve conductive self-repair. The ultra-fine silver-plated copper wire combined with the buffer liner greatly reduces the friction and wear of the single wire. The conductor torsional fatigue life exceeds 15 million times, which is far higher than that of traditional wires.
[0017] (2) The PTFE micro-nano textured super-smooth inner layer realizes the interface decoupling between the conductor and the insulation layer, eliminating torsional friction loss; the graphene TPV stress buffer layer effectively dissipates bending stress, and the silane coupling agent transition layer avoids interlayer peeling, thus improving the dynamic crack life of the insulation layer by more than 3 times.
[0018] (3) The double-layer wound nickel-plated LCP spiral reinforcement belt, combined with the elastic damping wire, transforms the concentrated torsional deformation into uniformly dispersed deformation, completely eliminating the problems of kinking and necking; the outer layer is covered with a wear-resistant ceramic micro coating, which improves the surface wear resistance, oil resistance and weather resistance by 2 times, making it suitable for complex industrial environments.
[0019] (4) The built-in fiber optic sensing unit can monitor the torsion angle, temperature and wire breakage status of the wire in real time, realizing the integration of conductivity and monitoring; the oval irregular cross section is adapted to the narrow space of the robot joint, and the hollow skeleton and optimized structure reduce the weight of the wire by 25% compared with traditional products of the same specification, which is in line with the trend of robot lightweighting.
[0020] (5) The process parameters such as vacuum infusion, plasma etching, and microwave irradiation crosslinking are precisely controllable, ensuring the consistency of the performance of the conductor batches. The preparation method is adapted to industrial continuous production and meets the needs of batch application. Attached Figure Description
[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0022] Figure 1 This is a schematic diagram of the structure of the present invention.
[0023] In the figure: 1. Composite stress conductor; 11. Polyimide buffer liner; 12. Hollow spiral magnesium-aluminum alloy skeleton; 13. Ultrafine silver-plated copper wire; 14. Doped carbon nanotube gallium-based liquid metal; 2. Gradient sliding insulating layer; 21. PTFE micro-nano textured super-slippery inner layer; 22. Graphene TPV stress buffer layer; 23. Irradiated cross-linked TPU tear-resistant outer layer; 24. Silane coupling agent transition layer; 3. Spiral reinforcing sheath; 31. Nickel-plated LCP spiral reinforcing tape; 32. Elastic damping wire; 33. Wear-resistant ceramic micro-coating; 4. Fiber optic sensing unit. Detailed Implementation
[0024] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.
[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0026] Figure 1 As shown, the conductor of the present invention consists of an optical fiber sensing unit 4, a composite stress conductor 1, a gradient sliding insulation layer 2, and a spiral reinforcing sheath 3 from the inside out. The overall cross-section is an oval irregular structure, which is suitable for the narrow installation space of robot joints.
[0027] The composite stress conductor 1 is centered on the optical fiber sensing unit 4. The innermost layer is a polyimide buffer liner 11. The outer side of the polyimide buffer liner 11 is a hollow spiral magnesium-aluminum alloy skeleton 12. The outer side of the hollow spiral magnesium-aluminum alloy skeleton 12 is a spirally twisted ultrafine silver-plated copper wire 13 with a diameter of 0.03~0.05mm. The gaps of the ultrafine silver-plated copper wire 13 are filled with vacuum-doped carbon nanotube gallium-based liquid metal 14. The multi-walled carbon nanotube doping amount is 1~3wt%. The liquid metal completely fills the gaps to form a parallel conductive network, realizing the self-repair of broken wires.
[0028] A gradient sliding insulating layer 2 is wrapped around the outside of the composite stress conductor 1. From the inside to the outside, it consists of a PTFE micro-nano textured super-lubricating inner layer 21, a silane coupling agent transition layer 24, a graphene TPV stress buffer layer 22, and an irradiated cross-linked TPU tear-resistant outer layer 23. The surface of the PTFE micro-nano textured super-lubricating inner layer 21 is provided with a micro-nano pit array, the coefficient of friction is ≤0.05, and the thickness is 0.03~0.08mm. The graphene TPV stress buffer layer 22 has a Shore hardness of 70~85A and a thickness of 0.2~0.5mm. The irradiated cross-linked TPU tear-resistant outer layer 23 has a cross-linking degree of 60%~85% and a thickness of 0.1~0.3mm. The interlayers are weakly bonded and decoupled at the interface through the silane coupling agent transition layer 24.
[0029] The spiral reinforced sheath 3 is wrapped around the outside of the gradient sliding insulation layer 2. The substrate is made of TPV or TPU material with a thickness of 0.3~0.8mm. The inside is embedded with nickel-plated LCP spiral reinforcing strips 31 wound in both directions, with a spiral angle of 35°~55° and a winding pitch of 5~15 times the outer diameter of the sheath. Elastic damping wires 32 are evenly distributed between the nickel-plated LCP spiral reinforcing strips 31. The outer surface of the sheath 3 is sprayed with a wear-resistant ceramic micro coating 33 to improve wear resistance and weather resistance.
[0030] The specific steps of the method for preparing the conductor of the present invention are as follows: S1 uses an extrusion stretching process to prepare a hollow spiral magnesium-aluminum alloy skeleton 12. A polyimide buffer liner 11 is composited on the inner wall of the hollow spiral magnesium-aluminum alloy skeleton 12 through a thermal composite process to ensure that the hollow spiral magnesium-aluminum alloy skeleton 12 and the buffer liner 11 are tightly bonded. S2 The ultra-fine silver-plated copper wire 13 is spirally twisted along the hollow spiral magnesium-aluminum alloy skeleton 12. The twisted conductor is placed in a vacuum infusion device, and the vacuum degree is controlled to be ≤-0.095MPa and the infusion temperature is 40~60℃. The gallium-based liquid metal 14 doped with carbon nanotubes is vacuum infused and cured to form a composite stress conductor 1. S3 uses plasma etching to treat the surface of PTFE material, prepares a micro-nano pit array to form a PTFE micro-nano textured super-slippery inner layer 21, and sequentially forms a silane coupling agent transition layer 24, a graphene TPV stress buffer layer 22, and an irradiated crosslinked TPU tear-resistant outer layer 23 through a multi-layer co-extrusion process to obtain a gradient sliding insulating layer 2. S4 involves double-winding the nickel-plated LCP spiral reinforcing belt 31 and the elastic damping wire 32 in opposite directions at a pitch of 35°~55° and 5~15 times the outer diameter of the sheath, simultaneously co-extruding and coating the TPV or TPU matrix, and spraying a wear-resistant ceramic micro coating 33 onto the outer surface of the sheath 3 to form the spiral reinforcing sheath 3. S5 integrates an optical fiber sensing unit 4 at the center of the composite stress conductor 1, performs microwave irradiation cross-linking treatment on the entire conductor, controls the cross-linking degree to 60%~85%, and obtains a finished product of a torsion-resistant and sway-resistant power transmission conductor for robots after shaping.
[0031] Example 1: Ultrafine silver-plated copper wire 13 with a diameter of 0.04 mm; multi-walled carbon nanotubes in gallium-based liquid metal 14 with a doping amount of 2 wt%; PTFE micro-nano textured super-smooth inner layer 21 with a thickness of 0.05 mm; graphene TPV stress buffer layer 22 with a thickness of 0.3 mm; irradiated cross-linked TPU tear-resistant outer layer 23 with a thickness of 0.2 mm; nickel-plated LCP spiral reinforcing tape 31 with a helix angle of 45°; winding pitch of 10 times the outer diameter of the sheath; sheath 3 with a thickness of 0.5 mm.
[0032] Tested results show that the conductor has a ±180° torsion life of 16.2 million cycles, a reciprocating oscillation life of 12.5 million cycles, and that the liquid metal forms a bypass conduction within 10ms after the conductor breaks. The insulation layer is free of cracks, the sheath is free of wear, and the conductor weight is reduced by 26% compared to traditional conductors of the same specification.
[0033] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A torsion-resistant and sway-resistant power transmission wire for robots, characterized in that, From the inside out, it includes a composite stress conductor (1), a gradient sliding insulation layer (2), and a spiral reinforcing sheath (3); the composite stress conductor (1) integrates an optical fiber sensing unit (4); the composite stress conductor (1) includes a hollow spiral magnesium-aluminum alloy skeleton (12), ultra-fine silver-plated copper wire (13), and gallium-based liquid metal (14) doped with carbon nanotubes; the gradient sliding insulation layer (2) has a three-layer gradient structure; the spiral reinforcing sheath (3) is embedded with a nickel-plated spiral reinforcing strip and an elastic damping wire (32).
2. The conductor according to claim 1, characterized in that, The innermost layer of the composite stress conductor (1) is provided with a polyimide buffer liner (11), the hollow spiral magnesium-aluminum alloy skeleton (12) is located outside the buffer liner (11), the ultra-fine silver-plated copper wire (13) is spirally twisted along the skeleton, and the gallium-based liquid metal (14) is vacuum-filled in the gaps between the copper wires.
3. The conductor according to claim 1, characterized in that, The gradient sliding insulating layer (2) consists of, from the inside out, a PTFE micro-nano textured super-slippery inner layer (21), a graphene TPV stress buffer layer (22), and an irradiated cross-linked TPU tear-resistant outer layer (23), with a silane coupling agent transition layer (24) between the layers.
4. The conductor according to claim 3, characterized in that, The PTFE micro-nano textured super-slippery inner layer (21) has a micro-nano pit array on its surface, a friction coefficient ≤0.05, and a thickness of 0.03~0.08mm; the graphene TPV stress buffer layer (22) has a Shore hardness of 70~85A and a thickness of 0.2~0.5mm.
5. The conductor according to claim 1, characterized in that, The spiral reinforced sheath (3) has a nickel-plated LCP spiral reinforced strip (31) inside, which is double-wound in both directions with a spiral angle of 35°~55° and a winding pitch of 5~15 times the outer diameter of the sheath.
6. The conductor according to claim 1, characterized in that, The outer surface of the spiral reinforced sheath (3) is covered with a wear-resistant ceramic micro-coating (33), and the sheath cross section is an oval irregular structure.
7. The conductor according to claim 1, characterized in that, The ultrafine silver-plated copper wire (13) has a diameter of 0.03~0.05mm, and the multi-walled carbon nanotube doping content in the gallium-based liquid metal (14) is 1~3wt%.
8. A method for preparing a torsion-resistant and sway-resistant power transmission wire for robots, characterized in that, Includes the following steps: S1 prepares a hollow spiral magnesium-aluminum alloy skeleton (12) with an inner wall composite polyimide buffer liner (11). S2 The ultra-fine silver-plated copper wire (13) is spirally twisted along the skeleton and vacuum-injected gallium-based liquid metal (14) doped with carbon nanotubes. S3 performs plasma etching on the inner layer of PTFE to form a micro-nano texture, and co-extrudes to form a gradient sliding insulating layer (2). S4 is formed by double-wound nickel-plated LCP reinforcing strip and elastic damping wire (32) and co-extruded into spiral reinforcing sheath (3). The S5 integrated fiber optic sensing unit (4) is used to obtain the finished conductor through microwave cross-linking.
9. The preparation method according to claim 8, characterized in that, The liquid metal injection process is vacuum injection, with a vacuum degree ≤ -0.095MPa and an injection temperature of 40~60℃.
10. The preparation method according to claim 8, characterized in that, After molding, the sheath is cross-linked by microwave irradiation, with a cross-linking degree of 60%~85%.