Tendon rope and preparation method and application thereof

Abstract

The invention belongs to the technical field of robot precision transmission, and particularly relates to a tendon rope and a preparation method and application thereof. The tendon rope comprises a rope body formed by weaving a plurality of strands of polymer fibers, and further comprises a creep-resistant reinforcing structure which is integrally formed in the rope body and used for inhibiting the polymer fibers from moving under a load.

Description

Technical Field

[0001] This invention belongs to the field of precision transmission technology for robots, and particularly relates to a tendon ligament, its preparation method, and its application. Background Technology

[0002] With the rapid development of robotics and artificial intelligence, high-performance automated equipment, represented by bionic robots, medical robots, and precision collaborative robots, is evolving towards miniaturization, lightweighting, and high dynamic response. Among these advanced devices, the drive system, as its core functional unit, directly determines the robot's motion accuracy, load capacity, and long-term reliability. Traditional drive solutions, such as rigid transmissions based on motors and reducers, while mature, suffer from complex structures, large inertia, and transmission backlash, increasingly limiting their application in space-constrained, high-dynamic-performance micro-joint scenarios (such as dexterous hands and endoscopic surgical instruments). Therefore, chordal drive systems, using high-performance fiber optic cables as the core force transmission element, have become a research hotspot and mainstream development direction in the field of micro-precision transmission due to their unique advantages such as light weight, high flexibility, smooth and backlash-free transmission, and the ability to achieve long-distance drive.

[0003] To meet the stringent requirements of the aforementioned application scenarios, an ideal drive chord must simultaneously possess ultra-high strength, extremely fine outer diameter, excellent flexibility and flexural fatigue life, and, crucially, long-term dimensional stability. In existing technologies, traditional metal microfilament ropes (such as micro-steel wire ropes) exhibit good dimensional stability, i.e., creep resistance, but their high density and rigidity make them prone to metal fatigue fracture under frequent small-radius bending. Furthermore, their high coefficient of friction poses a challenge to the efficiency and lifespan of the entire drive system. As an alternative, ropes made from high-performance polymer fibers such as ultra-high molecular weight polyethylene (UHMWPE), aramid, or PBO offer unparalleled advantages in strength-to-weight ratio and flexibility, but as drive components, they also face a fundamental technical bottleneck. The inherent creep characteristics of polymer materials—that is, under continuous tensile loads, the material undergoes slow and irreversible plastic deformation, resulting in a continuous, minute elongation of the chord length. This creep phenomenon is fatal in robot applications that require maintaining precise posture or outputting stable force for a long time. It causes the robot joints to gradually lose positioning accuracy, resulting in "position drift" and seriously affecting the long-term working accuracy and reliability of the system.

[0004] While existing technologies recognize the aforementioned problems, their solutions are incomplete. Most high-performance fiber ropes are designed for macroscopic applications such as shipbuilding and hoisting. Their multi-strand core-sheath structures struggle to maintain structural uniformity and dimensional consistency at the micrometer level, and their optimization primarily targets impact loads, failing to fundamentally address the microscopic creep problem. Current technologies generally lack a fundamental means to effectively suppress creep under long-term static or quasi-static loads at the microstructural level of the tendon rope while maintaining the core advantages of polymer fibers, such as lightweight, high strength, and flexibility. Therefore, there is an urgent need in this field for a novel technical solution to fundamentally suppress creep caused by microscopic relative slippage between polymer fibers in miniaturized, high-precision tendon rope drive systems, thereby eliminating the long-term drift problem in robot motion accuracy. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a tendon rope, its preparation method, and its application.

[0006] Firstly, a tendon ligament employs the following technical solution: A tendon cord comprising a cord body woven from multiple strands of polymer fibers, the tendon cord further comprising an anti-creep reinforcement structure integrally formed within the cord body for inhibiting the movement of the polymer fibers under load.

[0007] Furthermore, the creep-resistant reinforcement structure is an inorganic metal wire coaxially woven together with the polymer fiber; the volume fraction of the inorganic metal wire in the rope is 20% to 80%; the inorganic metal wire is selected from one or more of stainless steel wire, tungsten wire or its alloy wire, and molybdenum wire or its alloy wire.

[0008] Furthermore, the creep-resistant reinforcement structure is a permanent orientation structure formed by pre-stretching the molecular chains of the polymer fiber.

[0009] Furthermore, the creep-resistant reinforcement structure is a spot-welded network formed by interfacial crosslinking and curing of the crosslinking agent at the intersection and adjacent regions of the polymer fibers; the crosslinking agent is selected from one or more of epoxy resin, isocyanate prepolymer and thermotropic liquid crystal polymer.

[0010] Furthermore, the creep-resistant reinforcement structure is a stabilized microstructure formed in the rope body through thermomechanical shaping treatment.

[0011] Secondly, a method for preparing a tendon ligament, employing the following technical solution: A method for preparing a tendon ligament includes the following steps: Step (1): Provide multiple strands of polymer fibers; Step (2): Weave the polymer fibers into a rope; Step (3) Integrating an anti-creep reinforcement structure into the rope body to suppress the relative slippage of the polymer fibers under load.

[0012] Furthermore, in step (2), during the weaving process, the weaving angle is 30°~60° and the weaving tension is 0.8N~5N.

[0013] Furthermore, in step (3), the specific steps for forming the creep-resistant reinforced structure are as follows: during the weaving process in step (2), inorganic metal wires and polymer fibers are mixed and coaxially woven to form an integrated composite structure.

[0014] Furthermore, step (3) is performed after step (2) and includes at least one of the following processes: Pre-stretching treatment: At a temperature of 20℃~50℃, a constant tension of 60%~85% of the breaking tensile force is applied to the rope and the treatment is continued for 10min~30min to achieve the permanent orientation structure of the polymer fiber molecular chain. Interface cross-linking curing treatment: The rope is immersed in a cross-linking agent solution with a concentration of 5wt%~20wt% and cured at a temperature of 50℃~160℃ for 5min~25min to form a spot welding network between the intersections and adjacent areas of the polymer fibers. Thermomechanical shaping treatment: A constant tension of 15% to 50% of the breaking tensile force is applied to the rope body, and heat treatment is carried out in an inert atmosphere at a temperature of 50℃ to 220℃. The wire speed is 0.50 m / min to 3.00 m / min, and the treatment time is 2 min to 15 min, so as to form a stable microstructure in the rope body.

[0015] Thirdly, regarding the application of a tendon ligament, the following technical solution is adopted: Application of a tendon ligament as described above in the drive system of a bionic robotic hand, mechanical joint, or medical robot.

[0016] The beneficial effects of this invention are: This invention provides a tendon rope that fundamentally alters the internal stress and deformation mechanism by integrating an anti-creep reinforcement structure within a rope body woven from multiple strands of polymer fibers. In traditional pure fiber ropes, long-term load transmission primarily relies on inter-fiber friction, and the rearrangement of fiber molecular chains and microscopic slippage between fiber bundles are unavoidable, which is the root cause of macroscopic creep. In this invention, the integrated internal reinforcement structure constructs a stable mechanical constraint system or high-modulus skeleton within the rope body. When the tendon rope is subjected to long-term tensile loads, this structure firmly "locks" each polymer fiber in its relative position or directly assumes most of the function of maintaining dimensional stability, thereby significantly suppressing relative slippage between fibers at its source. Based on this inherent stabilization mechanism, the tendon rope prepared by this invention exhibits a creep variation consistently below 0.5% after bearing its rated working load and undergoing continuous testing for 100 hours, representing a performance improvement of tens of times compared to untreated similar fiber ropes. At the same time, this integrated internal structure greatly improves the structural integrity and wear resistance of the rope, enabling it to exceed 600,000 cycles of bending fatigue life. Thus, without sacrificing the lightweight and high-strength advantages of polymer materials, it endows the tendon rope with unprecedented long-term dimensional stability and ultra-high reliability. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the following is a further detailed description of this application. The described embodiments should not be regarded as limitations on this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] In the following description, references to "some embodiments" refer to a subset of all possible embodiments; however, it is understood that "some embodiments" may be the same or different subsets of all possible embodiments and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the invention have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the invention pertain. The terminology used in the embodiments of the invention is for the purpose of describing the embodiments of the invention only and is not intended to limit the invention.

[0019] Those skilled in the art should understand that, in the following description of the embodiments of the present invention, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0020] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0021] Those skilled in the art will understand that the numerical ranges in the embodiments of the present invention should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value and an intermediate value within the stated range, as well as any other stated value or an intermediate value within the stated range, is also included within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in embodiments or test cases of the invention. All references to this specification are generally incorporated herein by reference to disclose and describe methods and / or materials associated with said references. In the event of any conflict with any incorporated reference, the contents of this application shall prevail.

[0023] It should be noted that all raw materials and / or reagents in the embodiments of the present invention were purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0024] Example Example 1 This embodiment 1 provides a tungsten alloy wire / UHMWPE composite tendon rope and its preparation method, including the following steps: Material preparation and pretreatment: Prepare high-strength tungsten alloy wire bundles with a diameter of 0.10 mm (tensile strength of a single tungsten wire is 5500 MPa) and 150 denier ultra-high molecular weight polyethylene (UHMWPE) fiber filaments. Wind the UHMWPE fibers onto an I-beam and place them in a vacuum plasma treatment device for low-temperature plasma treatment at a power of 300 W for 3 minutes to improve their surface energy.

[0025] Plying: Two tungsten alloy wires and four UHMWPE fibers are plyed together using a co-directional twisting machine, with a twist rate of 150 twists / meter, to form a composite ply yarn.

[0026] Weaving: Load 12 strands of the above composite yarn onto a 12-spindle precision braiding machine, set the braiding angle to 48° (corresponding to a pitch of about 1.4mm), and keep the braiding tension constant at 1.1N to form a dense single-core rope.

[0027] End treatment and winding: A high-power laser (50W power, scanning speed 2mm / s) is used to instantly scan both ends of the rope, melting and sealing the surface fibers. Then, under a low tension of less than 5N, it is wound onto a constant tension reel at a speed of 3 m / min.

[0028] Performance characterization: The tendon cord has an outer diameter of 0.50±0.03mm and a breaking tensile strength ≥400N. After 100 hours of continuous loading at 230N, the creep rate is 0.15%. Bending fatigue life tests (bending radius 30-60mm, load 100-200N) show it can withstand over 600,000 cycles.

[0029] Example 2 This embodiment 2 provides a full PBO fiber tendon rope and its preparation method, including the following steps: Material preparation and weaving: 250 denier PBO fiber is selected, and a 12-spindle weaving machine is used to control the weaving angle at 45° (pitch of about 2.0mm) and the weaving tension at 1.4N to weave a dense rope with an outer diameter of 0.8mm.

[0030] Pre-stretching treatment: Apply a constant tension of 70% of the rope's breaking tensile force to the rope and continue the treatment for 20 minutes at room temperature (25℃).

[0031] Impregnation and crosslinking: The rope is passed through an impregnation tank containing a 10% solid content multifunctional epoxy resin solution at a speed of 2 m / min for about 5 minutes.

[0032] Scraping and curing: Excess resin is scraped off with a precision mold (0.85 mm aperture), and then cured in stages by passing it through a curing oven at 90°C (5 min) and 150°C (15 min).

[0033] End treatment and winding: The treated tendon rope is sealed with resin and wound up under low tension (<5N).

[0034] Performance characterization: The tendon cord has an outer diameter of 0.82±0.02mm and a breaking tensile strength ≥1100N. After being tested under a continuous load of 400N for 100 hours, the creep deformation is only 0.30%. Bending fatigue life tests (bending radius 30-60mm, load 300-400N) show that it can withstand more than 800,000 cycles.

[0035] Example 3 Example 3 provides a fully aramid fiber tendon rope and its preparation method, including the following steps: Material preparation and weaving: 1000 denier para aramid fiber is selected and a 12-spindle weaving machine is used to control the weaving angle at 50° (pitch of about 2.4mm) to weave a rope with an outer diameter of 1.7mm.

[0036] Thermomechanical shaping treatment: Under tension of 25% of its breaking tensile force, the rope is passed through a nitrogen-protected heat treatment furnace at 180°C, with the rope speed controlled at 1.5 m / min and the treatment time at 8 min.

[0037] End treatment and winding: Laser melting is used for end sealing, followed by winding under low tension (<5N).

[0038] Performance characterization: The outer diameter of this tendon rope is 1.72±0.03mm, and the breaking tensile strength is ≥2100N. After being tested under a continuous load of 600N for 100h, the creep deformation is 0.35%.

[0039] Example 4: Example 4 provides a molybdenum wire / LCP composite tendon rope and its preparation method, including the following steps: Material preparation and pretreatment: Prepare molybdenum wire with a diameter of 0.15mm (tensile strength not less than 2000MPa) and liquid crystal fiber (LCP) precursor with a diameter of 2000 denier. Perform plasma surface activation treatment on the LCP fiber (power 500W, time 1min).

[0040] Plying: A plying machine is used to combine one molybdenum wire with one LCP fiber to make the final rope have a metal volume fraction of 50%.

[0041] Weaving: Load 16 strands of the above-mentioned composite yarn onto a 16-spindle braiding machine, set the braiding angle to 40°, control the braiding tension at 2.5 N, and braid into a large-diameter rope.

[0042] End treatment and winding: The end treatment is performed by metal brazing to ensure that the metal wire and fiber ends are completely fixed. Then, it is wound up under low tension (<5N).

[0043] Performance characterization: The tendon rope has an outer diameter of 2.80±0.05mm and a breaking tensile strength ≥5500N. After being tested under a continuous load of 1500N for 100h, the creep deformation was 0.07%, demonstrating extremely high dimensional stability.

[0044] Example 5 Example 5 provides a full PI fiber tendon rope and its preparation method, including the following steps: Material preparation and weaving: 100 denier polyimide (PI) fiber is selected, and an 8-spindle weaving machine is used to control the weaving angle at 60° and the weaving tension at 0.8N to weave an extremely fine rope with an outer diameter of 0.35mm.

[0045] Pre-stretching treatment: Under moderate heating (50°C) conditions, a constant tension of 85% of the breaking tensile force is applied to the braided tendon rope for 30 minutes to achieve maximum permanent orientation and stress relaxation of the fiber molecular chains.

[0046] End treatment and winding: The ends are sealed with resin and then wound up under low tension (<5N).

[0047] Performance characterization: The outer diameter of this tendon rope is 0.35±0.03mm, and the breaking tensile strength is ≥180N. After being tested under a continuous load of 50N for 100 hours, the creep deformation is 0.40%.

[0048] Example 6 Example 6 provides a full UHMWPE fiber tendon rope and its preparation method, including the following steps: Material preparation and weaving: 400 denier UHMWPE fiber is selected and woven into a rope with an outer diameter of 1.0 mm using a 12-spindle weaving machine and a weaving angle of 50°.

[0049] Pre-stretching treatment: Apply a constant tension of 60% of the rope's breaking tensile force to the rope at room temperature for 10 minutes.

[0050] Thermomechanical shaping treatment: After pre-stretching, the rope is immediately passed through an inert atmosphere heat treatment furnace at 100℃ under a tension of 15% of its breaking tensile force, with a line speed of 4 m / min and a treatment time of 2 min.

[0051] End treatment and winding: After laser sealing, the ends are wound up under low tension (<5N).

[0052] Performance characterization: The outer diameter of this tendon rope is 1.01±0.02mm, and the breaking tensile strength is ≥1040N. After being tested under a continuous load of 350N for 100h, the creep deformation is 0.40%.

[0053] Example 7 Example 7 provides a fully aramid fiber tendon rope and its preparation method, comprising the following steps: Material preparation and weaving: 200 denier para aramid fiber is selected and woven into a rope with an outer diameter of 0.6 mm using a 16-spindle weaving machine and a weaving angle of 45°.

[0054] Impregnation and crosslinking: The rope is passed through an impregnation tank containing a 20% (w / w) solid content isocyanate prepolymer solution at a speed of 0.5 m / min for 10 min.

[0055] Scraping and curing: After liquid control by a precision mold, curing is carried out at 160℃ for 25 minutes.

[0056] End treatment and winding: After sealing the ends with resin, wind up under low tension (<5N).

[0057] Performance characterization: The tendon rope has an outer diameter of 0.63±0.02mm and a breaking tensile strength ≥500N. After being tested under a continuous load of 200N for 100h, the creep deformation is 0.25%, demonstrating excellent creep resistance.

[0058] Example 8 Example 8 provides a molybdenum wire / aramid composite tendon rope and its preparation method, including the following steps: Material preparation and pretreatment: Prepare molybdenum wire with a diameter of 0.08 mm and para-aramid fiber with 800 denier. Perform plasma treatment on the aramid fiber (power 200W, time 5min).

[0059] Plying: One molybdenum wire is twisted together with two strands of aramid fiber to a twist of 200 twists / meter.

[0060] Weaving: Load 12 strands of the above composite yarn onto the braiding machine, set the braiding angle to 55°, and the braiding tension to 3N.

[0061] End treatment and winding: Laser melting is used for end sealing, and winding is performed at a speed of 2 m / min.

[0062] Performance characterization: The outer diameter of this tendon rope is 2.0±0.04mm, and the breaking tensile strength is ≥2500N. After being tested under a continuous load of 800N for 100h, the creep deformation is 0.20%.

[0063] Example 9 Example 9 provides a fully aramid fiber tendon rope and its preparation method, comprising the following steps: Material preparation and weaving: 600 denier para aramid fiber is selected, and a 12-spindle weaving machine is used to control the weaving angle at 52° and the weaving tension is kept constant at 3N to weave a rope with an outer diameter of about 1.2mm.

[0064] Pre-stretching treatment: Apply a constant tension of 75% of the rope's breaking tensile force and continue to treat it at 40°C for 15 minutes to fully achieve the orientation of the molecular chains.

[0065] Impregnation and crosslinking: The pre-stretched rope is passed through an impregnation tank containing a 15% (w / w) solid content thermotropic liquid crystal polymer (TLCP) solution at a speed of 1.0 m / min.

[0066] Scraping and curing: After liquid control by a precision mold, the product is cured in a programmed temperature curing oven at 120°C for 10 minutes, and then heated to 180°C for 15 minutes, so that TLCP forms a strong "spot weld" network between the fibers.

[0067] Thermomechanical stabilization treatment: Finally, under a tension of 20% of its breaking tensile force, the rope is passed through an inert atmosphere heat treatment furnace at 220°C for final structural stabilization and internal stress release treatment.

[0068] End treatment and winding: Laser melting is used for end sealing, followed by low-tension winding.

[0069] Performance characterization: The tendon cord has an outer diameter of 1.21±0.03mm and a breaking tensile strength ≥1200N. After 100 hours of continuous loading at 500N, the creep variation was as low as 0.45%. This example demonstrates that combining multiple post-stabilization processes can achieve exceptional creep resistance.

[0070] Example 10 Example 10 provides an ultra-micro tungsten wire / UHMWPE composite tendon rope and its preparation method, including the following steps: Material preparation and pretreatment: Prepare ultrafine tungsten wires with a diameter of 0.03mm (tensile strength ≥5000MPa) and 100 denier UHMWPE fibers, and perform plasma pretreatment on the UHMWPE fibers with a power of 100W and a time of 5min.

[0071] Plying: One ultra-fine tungsten wire is plyed with two strands of UHMWPE fiber and slightly twisted (80 twists / meter) to form an ultra-fine composite ply yarn.

[0072] Weaving: Load 6 strands of the above composite yarn onto a 6-spindle precision weaving machine, set the weaving angle to 45°, the weaving tension to 1N, and weave to form an ultra-miniature rope with an outer diameter of 0.3mm.

[0073] End treatment and winding: Due to the extremely thin rope, high-precision laser (20W power, scanning speed 5mm / s) is used for end sealing to prevent fraying. It is then precisely wound up under extremely low tension (<1N).

[0074] Performance characterization: The tendon rope has an outer diameter of 0.30±0.03mm and a breaking tensile strength ≥200N. After being tested under a continuous load of 140N for 100 hours, the creep deformation was 0.20%. This embodiment demonstrates that the technical solution of the present invention is fully applicable to micro-drive scenarios with extremely stringent space requirements.

[0075] Example 11 Example 11 provides a full LCP fiber tendon rope and its preparation method, including the following steps: Material preparation and weaving: 1500 denier liquid crystal (LCP) fiber is selected and a 12-spindle weaving machine is used to control the weaving angle at 48° to weave a rope with an outer diameter of 1.5mm.

[0076] Impregnation and crosslinking: In this embodiment, only interfacial crosslinking and curing treatment is used. The woven rope is impregnated in a 12% (w / w) isocyanate prepolymer solution for 8 minutes.

[0077] Scraping and curing: After liquid control by precision mold, heat curing is carried out in an oven at 140℃ for 20 minutes.

[0078] End treatment and winding: The ends are sealed with resin glue and then wound up under low tension (<5N).

[0079] Performance characterization: The tendon cord has an outer diameter of 1.52±0.03mm and a breaking tensile strength ≥1100N. After being tested under a continuous load of 550N for 100 hours, the creep deformation was 0.50%. This example demonstrates that the interfacial cross-linking curing method of the present invention exhibits excellent creep resistance for different types of high-performance fibers (such as LCP) and different types of cross-linking agents (such as isocyanates), and has wide applicability.

[0080] Standard Example This embodiment provides a conventional high-performance braided UHMWPE tendon cord and its preparation method, including the following steps: Material preparation and pretreatment: 400 denier ultra-high molecular weight polyethylene (UHMWPE) fiber filaments are selected, and no plasma or surface activation treatment is performed.

[0081] Plying and braiding: Multiple raw filaments are joined together by a plying machine, and then the 12-ply ply is loaded onto a 12-spindle precision braiding machine. The braiding angle is set to 45° and the braiding tension is controlled at 1.5N to braid a regular rope with an outer diameter of about 1.0mm.

[0082] Post-treatment: No pre-stretching, interfacial cross-linking, or thermomechanical stabilization treatments are performed.

[0083] End treatment and winding: Laser is used to melt and seal both ends of the rope, and it is then wound up under low tension (<5N).

[0084] Performance characterization: The tendon ligament has an outer diameter of 1.0 ± 0.03 mm and a breaking tensile force of approximately 1040 N. After 100 hours of continuous loading at 350 N (approximately 32% of the breaking tensile force), the creep variation is as high as 2.5%. The bending fatigue life (bending radius 40 mm, load 150 N) is approximately 500,000 cycles.

[0085] Comparative Example Comparative Example 1 Comparative Example 1 provides a full PBO fiber tendon rope without any post-stabilization treatment and a method for its preparation, comprising the following steps: Material preparation and weaving: The rope was prepared using the same 250 denier PBO raw material and weaving parameters (12-spindle weaving machine, weaving angle 45°, weaving tension 1.4N) as in Example 2 of this invention.

[0086] Post-processing: All post-stabilization steps are omitted. That is, no pre-stretching treatment, nor impregnation crosslinking and curing treatment are performed.

[0087] End treatment and winding: The ends of the woven rope are directly sealed with resin and then wound up under low tension.

[0088] Performance characterization: After 100 hours of continuous load at 375 N, the creep variation was as high as 5.4%, which is 18 times that of Example 2 of this invention (creep variation 0.30%). Its bending fatigue life was also significantly reduced, only able to withstand about 300,000 cycles.

[0089] Comparative Example 2 Comparative Example 2 provides an aramid core rope reinforced with external metal wire winding and its preparation method, comprising the following steps: Material preparation and core rope preparation: 800 denier para aramid fiber is selected and 8-spindle braiding machine is used to braid an aramid core rope with a diameter of about 1.5mm.

[0090] Metal wire reinforcement treatment: Prepare stainless steel wire with a diameter of 0.15mm. Using a winding machine, tightly wrap two stainless steel wires around the outside of the aramid core rope at a certain pitch to form an outer metal reinforcement layer.

[0091] Post-treatment: The composite rope is subjected to a simple heat treatment at 120°C to release some of the stress.

[0092] End treatment and winding: The ends are sealed by metal brazing, followed by winding.

[0093] Performance characterization: The rope has an outer diameter of approximately 1.8 mm. After 100 hours of continuous loading at 600 N, the creep variation was approximately 4.07%. In bending fatigue testing, due to significant relative sliding and frictional wear between the inner and outer layers during bending, its fatigue life was less than 150,000 cycles, and the stainless steel wire broke.

[0094] Comparative Example 3 Comparative Example 3 provides a fully aramid tendon rope reinforced with surface coating and a method for its preparation, comprising the following steps: Material preparation and weaving: Using the same aramid fibers and weaving parameters as Comparative Example 1, an untreated aramid rope was prepared.

[0095] Surface coating treatment: The woven rope is passed through an impregnation tank containing a 25% polyurethane solution. Excess liquid is then scraped off using a mold, leaving only a thin protective coating on the rope surface. It is then dried at 80°C.

[0096] End treatment and winding: After the coating dries, end sealing and winding are performed.

[0097] Performance characterization: After 100 hours of continuous load at 400N, the creep variable was still as high as 3.7%.

[0098] Comparative Example 4 Comparative Example 4 provides a composite tendon rope using ordinary polymer monofilament as the reinforcing core and its preparation method, including the following steps: Material preparation and pretreatment: Prepare 150 denier UHMWPE fiber and 0.12mm diameter PET (polyethylene terephthalate) polymer monofilament. Although PET monofilament has high stiffness, it is still a polymer material and has creep characteristics.

[0099] Plitting and braiding: Using a process similar to that in Example 1, two PET monofilaments are plitting together with four UHMWPE fibers, and then the 12 strands of this composite yarn are braided.

[0100] End treatment and winding: After laser sealing, the ends are wound up.

[0101] Performance characterization: The outer diameter of this tendon cord is approximately 0.55 mm. After being tested under a continuous load of 230 N for 100 hours, the creep deformation was 7.9%.

[0102] Comparative Example 5 Comparative Example 5 provides a conventional miniature steel wire rope and its preparation method, comprising the following steps: Materials and Structure: Medical-grade 304 stainless steel microwires are used, with a single wire diameter of 0.05mm.

[0103] Preparation process: Using conventional wire rope twisting process, firstly, 7 single filaments are twisted into one strand, and then the 7 strands are twisted into a 7x7 structure miniature wire rope.

[0104] Post-processing: The prepared wire rope is pre-tensioned to eliminate some of the structural stress.

[0105] End treatment: The two ends are fastened with metal sleeves.

[0106] Performance Characterization: The outer diameter of this wire rope is 0.5 mm, comparable to that of Example 1. Under a continuous load of 230 N for 100 hours, the creep was extremely low, approximately 0.08%, demonstrating excellent dimensional stability. However, during bending fatigue life testing (bending radius 30 mm, load 100 N), due to the stress concentration and fatigue characteristics of the metal material itself, multiple filaments broke in less than 150,000 cycles, far below the lifespan of over 600,000 cycles achieved by the composite tendon rope of this invention. Furthermore, its mass per unit length is more than twice that of Example 1, and it exhibits extremely high bending stiffness but poor flexibility.

[0107] Comparative Example 6 Comparative Example 6 provides a core-sheath structure tendon cord with a metal wire as the straight core and a method for preparing the same, comprising the following steps: Materials and Structure: A 0.2mm diameter tungsten wire is selected as the straight core wire, and 150 denier UHMWPE fiber is selected as the sheath material.

[0108] Preparation process: Using the tungsten wire as the core, UHMWPE fibers are directly woven into a sheath layer on its outside using a 12-spindle braiding machine to form a core-sheath structure.

[0109] End treatment: The ends are sealed with resin glue.

[0110] Performance characterization: The rope has an outer diameter of approximately 0.55 mm. Under low loads, its creep performance is acceptable. However, during bending fatigue testing (bending radius 40 mm), due to the extreme stress concentration at the bending point caused by the rigid straight tungsten wire core, the core wire fractured from the outermost part of the bend in less than 80,000 cycles.

[0111] Comparative Example 7 Comparative Example 7 provides a fully aramid fiber tendon rope, which undergoes tension-free heat treatment, including the following steps: Material preparation and weaving: Using the same 1000 denier aramid fiber and weaving parameters as in Example 3, an untreated rope was prepared.

[0112] Post-treatment: The rope is placed in a 180°C oven for heat treatment for 8 minutes under no tension (relaxed state).

[0113] End treatment and winding: After cooling, the ends are sealed and wound up.

[0114] Performance characterization: The tendon rope has an outer diameter of approximately 1.7 mm. After being tested under a continuous load of 600 N for 100 hours, the creep deformation was 3.6%, which is a very limited improvement compared to the untreated rope.

[0115] Comparative Example 8 Comparative Example 8 provides a conventional braided tendon rope using higher modulus PBO fibers and a method for its preparation, comprising the following steps: Materials and Structure: High-modulus PBO fiber (HM-PBO) with a denier number of 250 is selected from commercially available fibers with a higher modulus than conventional PBO fibers.

[0116] Preparation process: Using the same conventional weaving process as in Example 1, 12 strands of HM-PBO fibers were woven into a rope with an outer diameter of approximately 0.8 mm.

[0117] Post-processing: All post-stabilization steps are omitted.

[0118] End treatment and winding: Perform routine laser end sealing and winding.

[0119] Performance characterization: The instantaneous breaking tensile strength of this tendon rope is extremely high, exceeding 1600N, and its initial modulus is also excellent. However, during long-term load testing (400N load for 100 hours), due to its unlocked internal microstructure, relative slippage between fibers still occurred, resulting in a final creep deformation of up to 2.9%.

[0120] Comparative Example 9 Comparative Example 9 provides a fully UHMWPE tendon rope reinforced with a plasma cross-linked surface and its preparation method, comprising the following steps: Material preparation and weaving: 400 denier UHMWPE fiber is used and conventionally woven into a rope with an outer diameter of 1.0 mm.

[0121] Post-processing: The woven rope is placed in a vacuum plasma treatment device and subjected to long-term, high-power plasma treatment (800W power, 30min) under a specific atmosphere.

[0122] End treatment and winding: After treatment, the ends are sealed and wound up.

[0123] Performance characterization: The treated rope surface became rough and slightly stiff. However, during long-term load testing (350N load, 100h), since the plasma's penetration depth was only at the nanometer to micrometer level, it could not affect the movement of most fibers inside the rope. The internal fiber slippage remained unimpeded, and the final measured creep was as high as 2.3%, which showed no substantial improvement compared to the untreated conventional example 1.

[0124] Comparative Example 10 Comparative Example 10 provides a composite rope made by simply twisting metal wire and aramid fiber, and a method for preparing the same, comprising the following steps: Materials and structure: The same 0.08mm molybdenum wire and 800 denier aramid fiber as in Example 8 were used.

[0125] Preparation process: Instead of using a braiding machine, a simple twisting machine is used to simply twist 12 strands of material (4 molybdenum wires and 8 strands of aramid fiber) together in the same direction to form a composite twisted rope.

[0126] End treatment: laser end sealing.

[0127] Performance Characterization: The outer diameter of this twisted rope is approximately 2.0 mm. In tensile testing, due to the uneven stress distribution caused by the components being bound only by friction, its breaking tensile strength is less than 1200 N, far lower than the 2500 N of Example 8. During bending, due to structural instability, "detwisting" and a "birdcage effect" (i.e., the wires bulging outwards) occur between the rigid metal wires and the flexible fiber bundles, resulting in a fatigue life of less than 50,000 cycles. Its creep deformation is also as high as 2.9% due to structural instability.

[0128] Performance testing To verify the actual effect of the technical solution of the present invention, the tendon ligament samples prepared in Examples 1-11, Conventional Example 1, and Comparative Examples 1-10 were subjected to the following performance tests.

[0129] I. Test Methods and Performance Indicators Outer diameter and dimensional tolerance testing A high-precision laser diameter gauge was used to measure the outer diameter at 10 different locations on each sample. The average value was calculated as the final outer diameter, and the dimensional tolerance range was determined based on the deviation between the maximum and minimum values.

[0130] Tensile strength test Quasi-static tensile tests were performed on tendon chord samples using a universal testing machine. Sample preparation: Samples with a length of 300 mm were cut, and both ends were sealed with epoxy resin to ensure reliable clamping. Test parameters: The gauge length was set to 150 mm, and the tensile rate was kept constant at 100 mm / min. The maximum load that the sample could withstand before breaking was recorded as its breaking tensile force. Five sets of tests were performed for each type of sample, and the average value was taken.

[0131] Creep performance test The creep testing was conducted using a constant load creep testing machine at room temperature (25℃±2℃). Sample preparation: Samples with an effective length of 300mm were cut and sealed at both ends. Testing procedure: First, a preload of 10N was applied to the sample to fully straighten it, and its initial length L0 was recorded using a high-precision displacement sensor. Then, according to the characteristics of different samples, a specific constant load was applied (as described in the various embodiments and comparative examples in the specification), and timing was started. After 100 hours of continuous loading, the length L of the sample at this point was recorded. 100 The creep variable (%) is calculated using the following formula: Creep variable (%) = [ ( L100 - L0) / L0] × 100%.

[0132] Bending fatigue life test A custom-designed reciprocating bending fatigue testing machine was used for testing. The testing apparatus included multiple pulleys of preset diameters and a linear actuator driven by a servo motor. Testing procedure: The tendon ligament sample was mounted on the testing machine and subjected to a 90° reciprocating bending motion on pulleys with a preset bending radius (e.g., 30-60 mm). Simultaneously, a specific constant tensile load was applied to the sample. The reciprocating motion frequency was set to 2 Hz, and one complete reciprocating motion was recorded as one cycle. The test was continued until the sample fractured, and the total number of cycles at this point was recorded as its bending fatigue life.

[0133] II. Test Results and Data Comparison All samples provided in Examples 1-11, Conventional Example 1, and Comparative Examples 1-10 were tested according to the above method, and the resulting performance data are summarized in Table 1 below.

[0134] Table 1: Comprehensive Comparison of Performance Data of Examples 1-11, Conventional Example 1, and Comparative Examples 1-10

[0135] Test data from Examples 1 to 11 of this invention show that, regardless of whether the technical approach of integrating inorganic metal wires and polymer fibers (Examples 1, 4, 8, 10) or the technical approach of pre-stretching, interfacial cross-linking, or thermomechanical setting of all polymer fibers (Examples 2, 3, 5, 6, 7, 9, 11) was adopted, the creep variable per 100 hours was successfully controlled at an excellent level of 0.07% to 0.50%, significantly lower than that of conventional untreated rope (2.5%) by an order of magnitude. Simultaneously, it exhibited good bending fatigue life, with some samples reaching over 600,000 cycles. This performance covers a wide outer diameter range from 0.3 mm to 2.8 mm and various high-performance fiber material systems such as UHMWPE, PBO, aramid, LCP, and PI, fully demonstrating the universality and effectiveness of the technical solution of this invention.

[0136] The data from Conventional Example 1 and Comparative Examples 1 to 10, from the opposite perspective, verify the necessity of the technical path of the present invention: the creep of conventionally woven or high-performance fiber ropes without any effective post-treatment (Conventional Example 1, Comparative Examples 1 and 8) is as high as 1.7% to 5.4%, which is several to tens of times higher than that of the embodiments of the present invention; any attempt to improve the creep performance through surface treatment (Comparative Examples 3 and 9), tensionless heat treatment (Comparative Example 7), or the use of reinforcing materials with creep properties (Comparative Example 4) cannot substantially improve the creep performance. At the same time, the samples using pure metal wire (Comparative Example 5) or obviously composite structures such as external winding, straight core, and simple twisting (Comparative Examples 2, 6, and 10) all have significantly lower bending fatigue life than the embodiments of the same specifications of the present invention.

[0137] The data comparison above shows that the core concept of "integrated internal anti-creep enhancement structure" proposed in this invention, through specific technical paths such as distributed metal composite or post-stabilization treatment that penetrates deep into the rope body, has successfully solved the technical contradiction of the difficulty in simultaneously meeting the requirements of high creep and high fatigue in polymer tendon ropes, and achieved excellent technical results.

[0138] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A tendon, characterized in that The tendon rope comprises a rope body woven by a plurality of polymer fibers, and further comprises an anti-creep reinforcing structure integrally formed inside the rope body for inhibiting the polymer fibers from moving under load.

2. The tendon as claimed in claim 1, characterized in that The anti-creep reinforcing structure is inorganic metal wires coaxially woven together with the polymer fibers; the volume fraction ratio of the inorganic metal wires in the rope body is 20% to 80%; and the inorganic metal wires are selected from one or more than two of stainless steel wires, tungsten wires or alloy wires thereof, and molybdenum wires or alloy wires thereof.

3. The tendon as claimed in claim 1, wherein The anti-creep reinforcing structure is a permanent orientation structure formed by pre-stretching the molecular chains of the polymer fibers.

4. The tendon as claimed in claim 1, wherein The anti-creep reinforcing structure is a spot-welding network formed by interfacial cross-linking solidification treatment of a cross-linking agent at the intersection and adjacent regions of the polymer fibers; and the cross-linking agent is selected from one or more than two of epoxy resin, isocyanate prepolymer, and thermotropic liquid crystal polymer.

5. The tendon as claimed in claim 1, wherein, The anti-creep reinforcing structure is a stabilized microstructure formed in the rope body by thermal mechanical setting treatment.

6. A method of manufacturing a tendon, characterized by The method comprises the following steps: Step (1), providing a plurality of polymer fibers; Step (2), weaving the polymer fibers into a rope body; Step (3), integrally forming an anti-creep reinforcing structure in the rope body to inhibit the relative slipping of the polymer fibers under load.

7. The production method according to claim 6, wherein In step (2), the weaving angle is 30° to 60°, and the weaving tension is 0.8 N to 5 N during the weaving process.

8. The preparation method according to claim 6, characterized in that, In step (3), the specific steps of forming the anti-creep reinforcing structure are as follows: during the weaving process of step (2), inorganic metal wires are coaxially woven together with the polymer fibers to form an integrated composite structure.

9. The preparation method according to claim 6, characterized in that, The step (3) is performed after step (2) and comprises at least one of the following treatments: Pre-stretching treatment: applying a constant tension of 60% to 85% of the breaking tension of the rope body to the rope body in a temperature environment of 20°C to 50°C for 10 min to 30 min to achieve a permanent orientation structure of the molecular chains of the polymer fibers; Interfacial cross-linking solidification treatment: immersing the rope body in a cross-linking agent solution with a concentration of 5wt% to 20wt% and performing solidification at a temperature of 50°C to 160°C for 5 min to 25 min to form a spot-welding network between the intersection and adjacent regions of the polymer fibers; Thermal mechanical setting treatment: applying a constant tension of 15% to 50% of the breaking tension of the rope body to the rope body, performing heat treatment in an inert atmosphere at a temperature of 50°C to 220°C, and moving at a speed of 0.50 m / min to 3.00 m / min for 2 min to 15 min to form a stabilized microstructure in the rope body.

10. Use of the tendon rope according to any one of claims 1 to 5 in a driving system of a bionic robot hand, a mechanical joint, or a medical robot.

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