Connecting wire assembly with good insulativity and manufacturing method

Abstract

The invention relates to the field of electrical connection, and discloses a connecting wire assembly with good insulativity and a manufacturing method, the assembly comprises a conductive wire core and a prefabricated insulating sleeve; the prefabricated insulating sleeve is formed by winding a composite film with a polyester surface facing inwards and an aramid fiber surface facing outwards, and a hard longitudinal welding ridge is formed at the lap joint through ultrasonic welding. The welding ridge forms a rigid support, a heat dissipation gap is constructed in the sleeve, and the non-lubrication smooth penetration of the conductive wire core is realized by matching with the low friction characteristic of the inner layer; and when the terminal is crimped, the welding ridge is passively collapsed to fill the internal gap of the terminal, so that alignment-free airtight blind pressing is realized. According to the invention, the defects of material burn-through, thickness reduction or surface wiredrawing caused by direct contact of a high-temperature heat source with the insulating layer are avoided; meanwhile, the prefabricated continuous compact welding ridge structure replaces a net structure of a traditional braided wire, so that the physical integrity of the insulating sleeve on the whole length is ensured, and the risk of electric leakage caused by structural gaps is effectively eliminated.

Description

Technical Field

[0001] This invention relates to the field of electrical connection technology, and in particular to a connecting wire assembly with good insulation and its manufacturing method. Background Technology

[0002] In electrical connection systems for motor winding leads, automotive wiring harnesses, and various industrial electrical equipment, insulated connection wire assemblies are crucial components ensuring safe operation. As modern industry increasingly demands higher production efficiency and product quality, the manufacturing of connection wire assemblies is gradually shifting from manual operation to fully automated assembly lines. This presents even more stringent challenges to the structural characteristics, material properties, and processing technology of insulating sleeves.

[0003] Currently, the widely used insulating sleeves in the industry mainly include heat shrink tubing, braided tubing, and film sleeves made of wound insulating film. Among them, film sleeves are widely used due to their lightweight and cost advantages. However, existing film sleeve manufacturing typically uses an online hot-pressing process (hot-pressing method) to fix the overlap seam. This high-temperature contact processing method has significant inherent defects: on the one hand, the continuous high-temperature heat source can easily cause excessive softening, thinning, or even carbonization of the insulating material at the overlap, destroying the original dielectric strength of the material, making the sleeve prone to leakage and breakdown in humid or salt spray environments; on the other hand, the joint formed by hot pressing lacks sufficient mechanical rigidity, causing the flexible film sleeve to easily collapse and flatten under gravity. This flattened structure causes a large area of ​​contact friction between the inner wall and the conductor core when it is inserted into the sleeve, resulting in a sharp increase in threading resistance. To solve this problem, existing processes often have to rely on spraying lubricants such as talcum powder or silicone oil, which not only pollutes the working environment but may also affect the electrical contact reliability of subsequent terminals.

[0004] Furthermore, to meet the high-speed requirements of automated production, connector assemblies typically require terminal crimping and wire harness bundling during assembly. However, existing insulating films (such as PET film) generally have smooth surfaces and low coefficients of friction, making it difficult for nylon cable ties to form effective frictional locking on the sleeve surface during subsequent bundling. This makes them prone to axial slippage or detachment under vibration or stress, forcing manufacturers to add additional heat-shrink or adhesive bonding processes, thus reducing production efficiency. Simultaneously, for sleeves made of harder materials or with thicker seams to address collapse issues, their rigid structure often interferes with the terminal crimping process. This necessitates the addition of additional visual recognition or mechanical positioning devices in automated crimping processes to adjust the circumferential angle (phase) of the sleeve to avoid the seam position. This alignment operation limits the implementation of blind crimping processes, becoming a bottleneck restricting the improvement of production speed.

[0005] In summary, how to solve multiple technical problems in the field of electrical connection technology, such as the difficulty of wire threading due to easy collapse of insulating sleeves, the difficulty of fixing due to slippery surfaces, and the difficulty of blind pressing due to hardness interference, while ensuring excellent leakage protection performance, is an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a connector assembly with good insulation and a manufacturing method thereof. This invention solves the problems of existing insulated connector assemblies, such as high resistance to wire threading and difficulty in automated production due to the easy collapse of the insulating sleeve during manufacturing, easy slippage of the bundled fixing due to the smooth outer surface, and poor insulation and sealing performance of traditional hot-stamping or braided structures, which leads to easy leakage.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A first aspect of the present invention provides a connecting wire assembly with good insulation.

[0008] The core of this component lies in its use of a pre-formed tubular insulation structure instead of the traditional in-line wrapping structure. Specifically, the component includes a conductive core and a pre-formed insulating sleeve covering it. Unlike conventional extruded tubes, this insulating sleeve is made by winding an insulating film, and a longitudinal weld ridge is introduced at the film overlap using an ultrasonic welding process.

[0009] Regarding the structural mechanism of longitudinal welded ridges: The longitudinal weld ridge is a product of the film material melting and then solidifying under ultrasonic energy, resulting in a higher physical density and hardness than the unwelded area. Mechanically, this weld ridge acts as a rigid skeleton on the flexible sleeve wall. This skeleton structure resists radial pressure, preventing the film sleeve from collapsing or adhering to the conductive core surface under natural conditions. This creates and maintains a physical gap (micro-air gap) between the inner wall of the insulating sleeve and the conductive core. The presence of this gap not only blocks capillary action but also significantly reduces the contact area between them, providing a structural basis for lubricant-free threading.

[0010] Regarding collaborative design at the material level: In the preferred technical solution, the insulating sleeve is made of a PNT composite material film with an asymmetric hierarchical structure. The design fully utilizes the anisotropy of the composite material. Inner interface: The inner surface of the sleeve is made of polyester (PET). Utilizing the low surface energy and smooth surface properties of polyester, a low-friction sliding interface is constructed, allowing the conductive core to overcome only minimal dynamic friction when inserted.

[0011] Outer interface: The outer surface of the sleeve is made of aramid material. The high wear resistance and surface roughness of aramid material create a high-friction engagement interface. When the outer binding wire is wound around this layer, the rough surface effectively restricts the axial movement of the binding wire, preventing the wire bundle from loosening.

[0012] Regarding the mating mechanism of terminal crimping: The terminals of this component are fixed by mechanical crimping. In the crimped area, the longitudinal weld ridges exhibit hard and tough mechanical properties. When the crimping flanges of the terminal's insulation layer close, regardless of the angle of the weld ridge in the circumferential direction, the radial closing force applied to the terminal is sufficient to cause plastic collapse of the weld ridge. This passive compressive deformation allows the weld ridge material to fill the microscopic gaps inside the terminal, avoiding damage to the crimping mold due to excessive local hardness, and ensuring the circumferential tightness of the terminal to the insulating sleeve, achieving a reliable connection without alignment.

[0013] A second aspect of the present invention provides a method for manufacturing a connector assembly with good insulation.

[0014] This manufacturing method changes the traditional process of wrapping and fixing at the same time, and establishes a process route of first making the tube, then threading the wire, and then crimping.

[0015] Regarding prefabrication and threading processes: In the pre-formed sleeve molding step, by controlling the ultrasonic welding energy and overlap width (e.g., less than 1.5 mm), the aforementioned longitudinal weld ridge is formed while creating the sealed tube body. In the subsequent tube insertion step, the core of the process lies in utilizing the supporting effect of the weld ridge on the tube body and the lubricating properties of the inner polyester material to achieve low-resistance and rapid insertion of the conductive core without adding liquid lubricant.

[0016] Regarding crimping and bundling processes: In the terminal crimping step, a blind crimping strategy is adopted. Utilizing the crushable characteristics of the longitudinal welding ridges, the manufacturing process eliminates the need for a rotating sleeve to align at a specific angle; the connection is directly completed using the impact force of the crimping die, thus improving the automated production cycle. In the wire bundling step, the wires are directly bundled onto the outer surface of the aramid material. The material's inherent physical roughness replaces the traditional method of fixing the wires by hot-melting the insulation layer, eliminating the potential risk of damage to the insulation layer from high-temperature heat sources and preventing wire pulling and burn-through.

[0017] In summary, the present invention has at least one of the following beneficial technical effects: 1. This invention utilizes the longitudinal welding ridges formed by ultrasonic welding to impart radial stiffness to the flexible thin-film sleeve, preventing the tube from collapsing and maintaining the micro-air gap in the inner wall. Combined with the low friction characteristics of the inner polyester material, it enables the conductive wire core to be inserted quickly with low resistance under lubricant-free conditions. At the same time, by utilizing the high surface roughness of the outer aramid material, the binding wire is directly locked by physical friction in the subsequent bundling process, preventing axial slippage of the binding wire without the need for auxiliary heat treatment.

[0018] 2. This invention utilizes the compressible deformation characteristics of the longitudinal welding ridge under the crimping force of the terminal, enabling the high-hardness welding ridge to undergo plastic collapse and fill the internal gap of the terminal during the crimping process. This eliminates the interference of the welding ridge hardness on the closure of the crimping mold, thereby allowing the alignment process for the circumferential phase of the sleeve to be omitted during the manufacturing process. This enables blind crimping operations at any angle, simplifying the manufacturing process, improving production cycle time, and ensuring connection reliability.

[0019] 3. This invention uses ultrasonic welding prefabrication process to replace the traditional online hot-fixing process, avoiding material burn-through, thinning, or surface wire drawing defects caused by direct contact of high-temperature heat source with the insulation layer; at the same time, the prefabricated continuous dense welded ridge structure replaces the traditional braided wire mesh structure, ensuring the physical integrity of the insulating sleeve along its entire length and effectively eliminating the risk of leakage caused by structural gaps. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the components of the present invention; Figure 2 This is a cross-sectional view of the wiring terminals of the present invention; Figure 3 This is a schematic diagram of the conductive wire core equipped with an insulating sleeve according to the present invention; Figure 4 This is a cross-sectional view of the insulating sleeve of the present invention.

[0021] Among them, 10 is the conductive core; 20 is the insulating sleeve; 21 is the longitudinal welding ridge; 40 is the terminal block; 41 is the core crimping part; 42 is the insulation layer crimping part; and 50 is the binding wire. Detailed Implementation

[0022] See attached document Figure 1 To be continued Figure 4 The present invention provides a connecting wire assembly with good insulation, which mainly includes a conductive core 10 and an insulating sleeve 20 covering the conductive core 10.

[0023] The conductive core 10 is a metallic conductor, such as copper or aluminum wire. The conductive core 10 is located within the internal cavity of the insulating sleeve 20, and the two are coaxially or nearly coaxially distributed. The outer diameter of the conductive core 10 is smaller than the inner diameter of the insulating sleeve 20, thus creating a gap between the outer surface of the conductive core 10 and the inner surface of the insulating sleeve 20.

[0024] The insulating sleeve 20 is a prefabricated tubular component. It is not directly coated onto the surface of the conductive core 10 through an extrusion process, but is made by winding an insulating film and then ultrasonically welding it. The insulating sleeve 20 has a longitudinal welded ridge 21 extending axially on its tube wall. This longitudinal welded ridge 21 is located in the overlapping area after the insulating film is wound, and is formed by ultrasonically fusing and solidifying the overlapping portion of the insulating film.

[0025] The longitudinal weld ridges 21 are continuously distributed along the axial direction of the insulating sleeve 20, extending throughout its entire length. In cross-section, the thickness of the longitudinal weld ridges 21 is greater than the wall thickness of the non-welded area of ​​the insulating sleeve 20. The material density of the longitudinal weld ridges 21 is higher than that of the non-welded area of ​​the insulating sleeve 20.

[0026] The insulating film used in the insulating sleeve 20 is a composite material film. After being wound into a tubular structure, the wall of the insulating sleeve 20 exhibits an asymmetrical hierarchical structure, specifically including an inner surface layer and an outer surface layer. The inner surface layer constitutes the inner wall of the insulating sleeve 20, directly facing the conductive core 10; the outer surface layer constitutes the outer wall of the insulating sleeve 20, facing the external environment.

[0027] The inner surface layer is made of polyester (PET). Polyester has a first coefficient of friction and a smooth surface. The inner surface layer provides a contact interface for the insertion of the conductive core 10. The outer surface layer is made of aramid material, such as aramid paper or an aramid fiber composite layer. Aramid material has a second coefficient of friction and a rough surface. The first coefficient of friction is less than the second coefficient of friction.

[0028] In a specific embodiment, the insulating sleeve 20 is made of PNT composite material, wherein the polyester layer is located on the inner side and the aramid layer is located on the outer side. The roughness Ra value of the outer surface layer is greater than that of the inner surface layer.

[0029] The length of the conductive core 10 is greater than the length of the insulating sleeve 20. The conductive core 10 passes through the insulating sleeve 20, and its end extends beyond the end face of the insulating sleeve 20. The length of the conductive core 10 extending beyond the end face of the insulating sleeve 20 is between 0.5 mm and 2.0 mm. This extension length is used for subsequent electrical connection with the conductive parts of the terminal block.

[0030] The overlap width of the insulating film at the joint is less than 1.5 mm. Except for the longitudinal weld ridge 21, the insulating sleeve 20 retains the original physical properties of the insulating film, with a smooth surface and no signs of heat-induced wire drawing. The insulating sleeve 20 maintains its tubular shape through the longitudinal weld ridge 21 and does not collapse when naturally placed.

[0031] See attached document Figure 1 To be continued Figure 4 During the forming process of the insulating sleeve 20, the insulating film is wound along its long axis, causing the two sides of the insulating film to form an overlap area in the circumferential direction. The width of the overlap area is controlled to be less than 1.5 mm. The welding head of the ultrasonic welding equipment acts on this overlap area, applying high-frequency vibration energy. This high-frequency vibration energy causes the polymer molecular chains at the contact interface of the insulating film in the overlap area to generate heat through friction, melt, and recrystallize. Specifically, the polyester material of the inner surface layer undergoes thermoplastic flow under the action of ultrasound, interpenetrates and fuses with the insulating film layer on the opposite side, and forms an integrated longitudinal welded ridge 21 after cooling and solidification.

[0032] The microstructure of the longitudinal weld ridge 21 is a dense, molten solidified body. Compared to the insulating film area that has not undergone ultrasonic welding, the longitudinal weld ridge 21 has a higher Young's modulus and hardness. The thickness of the longitudinal weld ridge 21 is 1.5 to 2.0 times the thickness of a single layer of insulating film (depending on the melt compression ratio). This thickness increase, combined with the material hardening effect, makes the longitudinal weld ridge 21 a rigid reinforcing unit on the wall of the insulating sleeve 20 in terms of mechanical properties.

[0033] like Figure 4 As shown, the longitudinal welded ridges 21 form the supporting framework of the insulating sleeve 20. Since the insulating film itself is a flexible material, without the support of the longitudinal welded ridges 21, the wound tube would naturally collapse and flatten under its own weight. In this embodiment, the longitudinal welded ridges 21 utilize their high bending stiffness to provide a shape-retaining force along the axial direction to the insulating sleeve 20, resisting radial collapse deformation. This shape-retaining force allows the insulating sleeve 20 to maintain a predetermined circular or near-circular cross-sectional shape in its free state.

[0034] Thanks to the shape-retention properties of the insulating sleeve 20, a heat dissipation gap is formed between the inner surface layer of the insulating sleeve 20 and the outer surface of the conductive core 10. This heat dissipation gap is an air layer continuously distributed along the axial direction. When the conductive core 10 is inserted into the insulating sleeve 20, since the insulating sleeve 20 does not collapse, the contact between the conductive core 10 and the inner surface layer is a line contact or partial point contact, rather than a fully enclosed surface contact. The existence of the heat dissipation gap reduces the frictional contact area during insertion and provides an air insulation layer and a heat convection channel for the module.

[0035] When subjected to external radial pressure less than a predetermined threshold, the insulating sleeve 20 maintains its tubular structure by relying on the rigidity of the longitudinal weld ridge 21; when subjected to external radial pressure exceeding the predetermined threshold (e.g., in the terminal crimping process), the longitudinal weld ridge 21 has the characteristic of being compressible and deformable, and can undergo plastic collapse to adapt to the external spatial shape.

[0036] See attached document Figure 1 To be continued Figure 4 This invention provides a method for manufacturing a connector assembly with good insulation, the method comprising the following steps: S1. Pre-fabricated sleeve forming steps: In step S1, a roll of insulating film raw material is first provided. The selected insulating film is a double-layer or multi-layer composite film with a polyester side and an aramid side. The insulating film is conveyed longitudinally and wound into a tubular structure using an automated winding device. During the winding process, the layer orientation of the insulating film is strictly controlled by a guiding fixture: the smooth polyester side is controlled to face the inside of the pre-fabricated insulating sleeve 20, forming the inner surface layer; the rough and wear-resistant aramid side is controlled to face the outside of the pre-fabricated insulating sleeve 20, forming the outer surface layer.

[0037] The two edges of the insulating film overlap after winding, with the overlap width controlled within the range of 0.5 mm to 1.5 mm by a limiting device. The horn of the ultrasonic welding equipment, in conjunction with the anvil, applies mechanical vibration and pressure at a frequency of 20 kHz to 40 kHz to the continuously conveyed overlap area. Ultrasonic energy acts only on a localized area of ​​the overlap width, causing the thermoplastic polyester layers to melt and bond, forming a continuous longitudinal weld ridge 21. After welding, the continuous tube is cut into prefabricated single-unit insulating sleeves 20 of predetermined length using a cutting device. During this process, the energy output of the ultrasonic welding is set to a threshold sufficient to fuse the polyester layers but insufficient to damage the aramid layer structure, ensuring the physical integrity of the sleeve's outer surface.

[0038] S2. Conductive core preparation steps: Provide raw metal wires, use a wire cutting and stripping machine to cut the conductive wire core 10 to a predetermined length, and remove the original insulation (if any) at both ends of the wires to expose the bare metal conductor portion.

[0039] S3. Pipe threading procedure: The cut conductive core 10 is inserted axially and passes through the internal cavity of the prefabricated insulating sleeve 20. In this step, the insulating sleeve 20 is fixed or held as a separate rigid or semi-rigid component, and the conductive core 10 is pushed in as a moving part.

[0040] The dynamic characteristics of the tube insertion process depend on the structural stiffness and inner wall friction characteristics of the insulating sleeve 20. Utilizing the radial support force provided by the longitudinal welding ridge 21, the prefabricated insulating sleeve 20 maintains its cylindrical shape and does not collapse. The designed inner diameter of the prefabricated insulating sleeve 20 is larger than the designed outer diameter of the conductive core 10, forming a clearance fit between them.

[0041] During insertion, due to the presence of heat dissipation gaps, the outer surface of the conductive core 10 and the inner surface layer of the prefabricated insulating sleeve 20 are primarily in a non-contact or intermittent line contact state, rather than a full-circumferential surface contact state. This significant reduction in contact area lowers sliding resistance. Simultaneously, because the inner surface layer is made of polyester, its first coefficient of friction (dynamic coefficient of friction) is at a low level (e.g., less than 0.3). This combination of a low-friction surface and a micro-gap structure allows the conductive core 10 to smoothly pass through the entire length of the prefabricated insulating sleeve 20 with low resistance without being coated with any liquid lubricant (such as talc, silicone oil, etc.).

[0042] The insertion process continues until the end of the conductive core 10 protrudes from the end face of the prefabricated insulating sleeve 20. Using an axial limiting stop on the tooling, the relative axial position of the prefabricated insulating sleeve 20 on the conductive core 10 is calibrated, precisely controlling the exposed length of the conductive core 10 end to be between 0.5 mm and 2.0 mm, thus reserving a defined electrical connection area for subsequent terminal crimping steps.

[0043] S4. Terminal crimping procedure: After the conduit is inserted, the exposed end of the conductive core 10 is crimped and fixed with terminals. The terminal 40 is made of engineering plastic and its structure includes a core crimping part 41 at the front end and an insulation layer crimping part 42 at the rear end. The exposed part of the conductive core 10 is placed inside the core crimping part 41, and the end of the insulating sleeve 20 is placed inside the insulation layer crimping part 42.

[0044] The terminal crimping die applies radial closing pressure. At the core crimping portion 41, the metal flaps curl inward and pierce the oxide layer (if present) on the surface of the conductive core 10, achieving electrical connection and mechanical locking between the conductive core 10 and the terminal 40. At the insulation layer crimping portion 42, the metal flaps (typically an F-type or O-type crimping structure) surround and cover the outer surface layer of the insulating sleeve 20.

[0045] In this step, a blind pressing process without alignment is implemented. Because the prefabricated insulating sleeve 20 is not aligned at a specific circumferential angle during insertion, the longitudinal weld ridges 21 are randomly distributed circumferentially within the insulating layer crimping portion 42 (e.g., located at the top closed gap, bottom, or side). The material hardness of the insulating layer crimping portion 42 is higher than the polymer material hardness of the longitudinal weld ridges 21. Under the strong radial impact force of the crimping die, forced plastic deformation occurs regardless of the position of the longitudinal weld ridges 21.

[0046] Specifically, when the longitudinal welding ridge 21 is located at the wing-closed gap of the insulating layer crimping portion 42, the longitudinal welding ridge 21 is squeezed and collapsed by the end of the wing, and its material volume flows to both sides to fill the cavity below the gap; when the longitudinal welding ridge 21 is located at the bottom or side wall of the insulating layer crimping portion 42, the longitudinal welding ridge 21 is flattened and thinned, and its protruding volume is compressed into the gap inside the insulating sleeve 20, forcing the inner surface layer of the insulating sleeve 20 to tightly adhere to the conductive core 10. This crimping using the crushable characteristic of the longitudinal welding ridge 21 eliminates the interference of the rigid spine on the terminal closure shape, ensuring that the insulating layer crimping portion 42 forms a mechanically encapsulated structure with good airtightness, and the pull-out force meets industrial standards.

[0047] S5. Bundling and binding steps After the terminal crimping is completed, the wire bundling step is performed. Multiple pre-prepared wire assemblies are gathered and organized according to electrical wiring requirements to form a wire harness assembly. Binding wires 50 (such as nylon cable ties, polyester binding ropes, or acetate cloth tape) are used to wrap and secure the pre-fabricated insulating sleeve 20.

[0048] The binding wire 50 directly contacts and secures itself to the outer surface layer of the prefabricated insulating sleeve 20. Because the outer surface layer is made of aramid fiber, its surface has microscopic fibrous protrusions and a high secondary coefficient of friction. When a radial tightening force is applied to the binding wire 50, a high-friction mechanical engagement interface is formed between the inner surface of the binding wire 50 and the outer surface layer. This mechanical engagement interface provides sufficient axial static friction without requiring a hot air gun or heating equipment to heat-melt the insulating sleeve 20, thus limiting the binding wire 50 from sliding or loosening along the axial direction of the insulating sleeve 20. The entire bundling process is completed at room temperature, maintaining the physical structural integrity of the insulating sleeve 20 and avoiding thickness reduction or carbonization damage to the insulating film caused by high-temperature heat sources.

[0049] The foregoing detailed embodiments illustrate the overall structure of the connector assembly of the present invention, the microscopic forming mechanism of the longitudinal welding ridge, and the related manufacturing process. Given that the technical effects of the present invention—particularly the leakage prevention performance of the insulating sleeve, the low resistance characteristics during tube insertion, and the structural adaptability during terminal crimping—deeply depend on the physicochemical properties of the selected polymer composite material and the specific process parameters of ultrasonic welding, in order to further fully disclose the technical details of the present invention and verify the feasibility and superiority of the above structure in practical applications using experimental data, the following provides a further quantitative explanation and verification of the technical solution of the present invention, combining specific raw material specifications, preparation parameters, examples, comparative examples, and corresponding performance test results.

[0050] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a standard prefabricated insulating sleeve.

[0051] The polyester / aramid composite insulating film (total thickness 0.25 mm) from the aforementioned raw materials was selected and cut into strips with a width of 12 mm using a slitting machine. This strip was then introduced into the forming mold cavity of an automatic winding and welding equipment. Guide rollers controlled the polyester side of the strip to face inwards and the aramid side to face outwards. The forming mold was adjusted so that the two edges of the strip met at the top of the circumference, and the overlap width was controlled to 1.0 mm using a limit gauge. The ultrasonic welding system was started, with the working frequency set to 35 kHz, the welding head pressure to 0.35 MPa, the amplitude to 25 μm, and the traction speed to 5 m / min. The welding head was pressed against the overlap, and the high-frequency vibration melted and then solidified the inner polyester material at the overlap, forming a continuous longitudinal welding ridge. After cutting, a prefabricated insulating sleeve A1 with a length of 100 mm and an inner diameter of approximately 3.5 mm was obtained.

[0052] Preparation Example 2: This preparation example provides a prefabricated insulating sleeve with a narrow overlap width.

[0053] Except for adjusting the limiting gauge of the molding die to control the overlap width to 0.5 mm, all other raw materials and process parameters remained the same as in Preparation Example 1. Due to the reduced overlap area, the welding amplitude was fine-tuned to 28 μm to ensure welding strength. Pre-fabricated insulating sleeve A2 was obtained through this process. Upon inspection, the longitudinal weld ridge of insulating sleeve A2 was relatively narrow, but the roundness of the tube body was still maintained, and no cracking occurred.

[0054] Preparation Example 3: This preparation example provides a prefabricated insulating sleeve with a wide overlap width.

[0055] Except for adjusting the limiting gauge of the molding die to control the overlap width to 1.5 mm, all other raw materials and process parameters were consistent with those in Preparation Example 1. Due to the wider overlap layer, the molten area increased, resulting in a prefabricated insulating sleeve A3. Measurements showed that the longitudinal weld ridge of the insulating sleeve A3 was wider, the tube body was more rigid, and its shape retention was better than that in Preparation Example 1 when placed vertically.

[0056] Preparation Example 4: This preparation example provides a prefabricated insulating sleeve with a high-hardness welded ridge.

[0057] The raw materials and overlap width (1.0 mm) used were consistent with those in Preparation Example 1. In the welding process, the ultrasonic energy output was increased, and the welding head pressure was set to 0.50 MPa with an amplitude of 35 μm. Under this high energy, the polyester layer at the overlap melted more fully, the compression ratio increased, and the aramid layer structure became more compact. A pre-fabricated insulating sleeve A4 was thus obtained.

[0058] Comparative preparation examples 1-3: Comparative Preparation Example 1: This comparative preparation example provides an insulating sleeve made using a traditional hot stamping process, used to compare insulation performance and structural stiffness.

[0059] The same polyester / aramid composite insulating film as in Example 1 was selected, and the winding method was the same, with the overlap width controlled at 1.0 mm. Instead of ultrasonic welding, a constant-temperature metal iron set to 320°C was used to press and iron the overlap. Heat was conducted through the aramid layer to the polyester layer, softening and bonding it. This resulted in the heat-pressed insulating sleeve D1. Observation revealed that due to high-temperature conduction, the aramid layer on the surface of sleeve D1 showed slight yellowing discoloration, and the hardness at the bonding point did not increase significantly. The sleeve also exhibited a flattened shape when laid flat.

[0060] Comparative Preparation Example 2: This comparative preparation example provides an insulating sleeve made of all-polyester material for comparing surface friction characteristics.

[0061] A single-layer polyester film (PET film, 0.25 mm thick, with smooth inner and outer surfaces) from the aforementioned raw materials was selected to replace the composite film. The same ultrasonic welding process and parameters (overlap width 1.0 mm) as in Preparation Example 1 were used for fabrication. Due to the different energy absorption efficiency of PET materials, the amplitude was fine-tuned to 20 μm to prevent burn-through. A fully polyester insulating sleeve D2 was obtained. The friction coefficients of the inner and outer surfaces of this sleeve are the same, both exhibiting a low-friction state.

[0062] Comparative Preparation Example 3: This comparative preparation example provides an insulating sleeve made using an adhesive bonding process, used to compare the supporting effect of the welded ridge.

[0063] The same polyester / aramid composite insulating film as in Example 1 was selected. During the winding process, ultrasonic welding was not used; instead, a layer of polyurethane adhesive, approximately 1.5 mm wide, was applied to the overlap using a dispensing needle. After UV curing, a tubular shape was formed. This yielded adhesive-bonded insulating sleeve D3. Inspection revealed that the adhesive-bonded joint was relatively soft and possessed a certain degree of elasticity, failing to form a rigid spine. Under gravity, the sleeve completely collapsed and closed.

[0064] Examples 1-4: Example 1: This embodiment provides a connector assembly with good insulation and its manufacturing method, using the prefabricated insulating sleeve A1 from Preparation Example 1. The manufacturing and assembly of this assembly includes the following steps: Conductor preparation: Select multi-strand stranded tinned copper wire with a cross-sectional area of ​​2.5 square millimeters as the conductive core and cut it to a total length of 150 millimeters. Use a wire stripper to remove the original insulation at one end of the conductor, or use bare copper stranded wire directly, ensuring that the conductor end is clean and free of oxidation.

[0065] Unlubricated insertion: Use the prefabricated insulating sleeve A1 (overlap width 1.0 mm) prepared in Preparation Example 1. Fix the prefabricated insulating sleeve A1 to the tooling fixture, keeping the sleeve vertical or horizontal. Insert the conductive core directly into the internal cavity of the prefabricated insulating sleeve A1. During insertion, do not coat the conductive core or the inner wall of the insulating sleeve with talcum powder, silicone oil, or any liquid lubricant. Utilize the low coefficient of friction of the inner polyester material and the heat dissipation gaps provided by the longitudinal welded ridges to completely pass the conductive core through the sleeve.

[0066] Position calibration: Adjust the relative axial position of the conductive core and the prefabricated insulating sleeve A1 so that the end of the conductive core extends 1.0 mm beyond the end face of the prefabricated insulating sleeve A1.

[0067] Blind Crimping Connection: Place the above assembly into the die of the terminal crimping machine. Place the protruding portion of the conductive core into the core crimping part of the terminal, and place the end of the prefabricated insulating sleeve A1 into the insulation layer crimping part of the terminal. Without rotating and adjusting the circumferential angle of the prefabricated insulating sleeve A1, start the crimping machine directly. The die applies radial pressure, causing the metal flaps of the terminal to close. During this process, the longitudinal weld ridge undergoes plastic flattening deformation under the pressure of the metal flaps, filling the internal gaps of the insulation layer crimping part, thus completing the mechanical fixation.

[0068] Example 2: This embodiment provides a connector assembly with good insulation and its manufacturing method, using the prefabricated insulating sleeve A2 from Preparation Example 2. The manufacturing and assembly of this assembly includes the following steps: Conductor preparation: Select conductive wire cores of the same specifications as in Example 1 and cut them to a length of 150 mm.

[0069] Unlubricated conduit insertion: The prefabricated insulating sleeve A2 (overlap width 0.5 mm) prepared in Preparation Example 2 was used. The conductive core was inserted into the sleeve without any lubricant. Due to the narrow overlap width, the inner wall of the sleeve was highly uniform, and the insertion resistance remained at a low level.

[0070] Position calibration: Control the length of the end of the conductive core extending out of the prefabricated insulating sleeve A2 end face to be 0.5 mm.

[0071] Blind crimp connection: The assembly is placed into a terminal crimping machine. The ends are crimped and fixed. Due to the narrow overlap and the small material volume of the longitudinal weld ridge, the weld ridge is completely crushed and embedded in the aramid surface fibers under the strong closing of the insulation layer crimping part, resulting in extremely high adhesion between the terminal metal flap and the sleeve surface, forming a tight, airtight covering.

[0072] Example 3: This embodiment provides a connector assembly with good insulation and its manufacturing method, using the pre-fabricated insulating sleeve A3 from Preparation Example 3. The manufacturing and assembly of this assembly includes the following steps: Conductor preparation: Select conductive wire cores of the same specifications as in Example 1 and cut them to a length of 150 mm.

[0073] Unlubricated conduit insertion: The prefabricated insulating sleeve A3 (overlap width 1.5 mm) prepared in Preparation Example 3 was used. The conductive core was inserted into the sleeve. Although the increased overlap width led to a wider longitudinal weld ridge, the longitudinal weld ridge improved the overall radial stiffness of the tube body, resulting in good tube body roundness retention. The contact area between the conductive core and the tube wall remained small, and dry conduit insertion was successfully completed.

[0074] Position calibration: Control the length of the end of the conductive core extending out of the prefabricated insulating sleeve A3 end face to 2.0 mm to increase the conductive contact area.

[0075] Blind crimp connection: Perform terminal crimping operation. Due to the wider and harder longitudinal weld ridge, the pressure setting applied by the crimping die is increased by 5% compared to Example 1. At the moment of crimping, the wider longitudinal weld ridge undergoes forced displacement and compression, and its material flows to both sides, filling the microscopic gaps at the terminal R-corner and effectively preventing the terminal from loosening.

[0076] Example 4: This embodiment provides a connector assembly with good insulation and its manufacturing method, using the prefabricated insulating sleeve A4 from Preparation Example 4. The manufacturing and assembly of this assembly includes the following steps: Conductor preparation: Select conductive wire cores of the same specifications as in Example 1 and cut them to a length of 150 mm.

[0077] Unlubricated conduit insertion: The prefabricated insulating sleeve A4 (high-energy welding, high-hardness ridge) prepared in Preparation Example 4 was used. The conductive wire core was inserted into the prefabricated insulating sleeve A4. Due to the high hardness of the longitudinal welding ridge of the prefabricated insulating sleeve A4, it effectively resisted the collapse of the tube body caused by gravity, maintained a uniform heat dissipation gap along the entire length of the sleeve, and made the wire insertion process smooth.

[0078] Position calibration: Control the length of the end of the conductive core extending out of the prefabricated insulating sleeve A4 end face to be 1.5 mm.

[0079] Blind crimp connection: Terminal crimping is performed. During the crimping process, the high-hardness longitudinal weld ridges undergo fracture-like collapse under the shear and compressive forces of the terminal metal flaps, rather than simple elastic deformation. This collapse mode allows the insulation material to be tightly engaged in the barbed grooves on the inner wall of the terminal, improving the component's pull-out resistance.

[0080] Bundling: The crimped components are bundled together with two other components of the same specification. Nylon cable ties are used to wrap directly around and tighten the aramid outer surface layer in the middle of the prefabricated insulating sleeve A4, with the cable tie tension set to 60N. The high coefficient of friction of the aramid layer prevents axial slippage of the cable ties.

[0081] Comparative Examples 1-4: Comparative Example 1: Compared with Example 1, the difference is that the prefabricated insulating sleeve A1 in Example 1 was replaced with the hot-pressed insulating sleeve D1 (hot-press ironing process) of Comparative Example 1. During the manufacturing process, due to the lack of rigid support at the hot-pressed joint, the tube body is flattened, requiring manual assistance to flare the opening during insertion, and the insulation layer is prone to cracking at the hot-pressed joint during terminal blind pressing. The remaining process steps and raw material specifications are the same as in Example 1.

[0082] Comparative Example 2: Compared with Example 1, the difference is that the pre-fabricated insulating sleeve A1 in Example 1 was replaced with the all-polyester insulating sleeve D2 (with smooth PET layers inside and out) from Comparative Example 2. In the bundling step, the nylon cable ties directly contact the smooth PET outer surface. The remaining process steps and raw material specifications are the same as in Example 1.

[0083] Comparative Example 3: Compared with Example 1, the difference is that the prefabricated insulating sleeve A1 in Example 1 was replaced with the adhesive insulating sleeve D3 (bonded with polyurethane adhesive) of Comparative Example 3. Because the adhesive joint is soft and elastic, it cannot form a rigid spine, and the sleeve naturally flattens before threading, resulting in increased threading resistance. The remaining process steps and raw material specifications are the same as in Example 1.

[0084] Comparative Example 4: Compared to Example 1, the difference is that a commercially available PET braided tubing (conventional expansion sleeve) is used instead of the prefabricated insulating sleeve A1 in Example 1. This braided tubing is made of PET monofilaments and has a porous mesh structure. In the terminal crimping step, the ends need to be pre-wrapped with heat shrink tubing to prevent the braided threads from unraveling, adding a step. The remaining process steps and raw material specifications are the same as in Example 1.

[0085] Test example: To verify the technical effectiveness of the insulated connecting wire assembly provided by the present invention in terms of manufacturing process adaptability, electrical safety and structural stability, the following test methods were used to test the embodiments and comparative examples.

[0086] Test items and methods: Test Item 1: Pipe threading resistance test (characterizing automatic threading efficiency) Test objective: To quantify the dynamic frictional resistance when a conductive wire core is inserted into a prefabricated insulating sleeve. A lower resistance value indicates greater suitability for continuous operation of an automated production line.

[0087] Testing equipment: Universal material testing machine (equipped with a 50N micro-range sensor), special pipe fixing clamps.

[0088] Test steps: The prefabricated insulating sleeve to be tested is vertically fixed in the lower clamp, keeping the sleeve naturally straight.

[0089] Clamp the upper end of the conductive wire core onto the fixture on the testing machine and align it with the center of the upper port of the sleeve.

[0090] Set the downward speed of the testing machine to 100 mm / min and push the conductive core into the sleeve.

[0091] Record the maximum thrust (N) during the passage of the conductive wire core. Five samples were tested for each embodiment or comparative example, and the arithmetic mean was taken.

[0092] Test Item 2: Insulation withstand voltage and leakage current test (characterizing electrical insulation integrity) Test objective: To test the insulation tightness of insulating sleeves, especially at longitudinal welded ridges / joints.

[0093] Test standard: Refer to IEC60034 Insulation Specification for Rotating Electrical Machines.

[0094] Test steps: Prepare a 300mm long connector assembly sample with the conductive cores at both ends exposed.

[0095] The middle 250mm of the sample was bent into a U-shape and immersed in a water tank containing a 5% NaCl aqueous solution, with both ends exposed above the water surface.

[0096] A power frequency AC voltage of 3000V is applied between the conductive wire core and the aqueous solution.

[0097] Maintain the voltage for 60 seconds and monitor the leakage current (mA) in the circuit.

[0098] Judgment criteria: If the leakage current exceeds 10mA or a breakdown arc occurs, it is judged as a failure; otherwise, the steady-state value of the leakage current is recorded.

[0099] Test Item 3: Axial Anti-slip Force Test of Binding Wire (Characterizing the Reliability of Bundle Fixation) Test Purpose: To verify the frictional locking ability of the outer surface of the sleeve to the binding material.

[0100] Test steps: Use a standard nylon cable tie (3.6mm wide) to secure the cable in the middle of the connection assembly.

[0101] Apply a radial tightening force of 50N using a constant torque cable tie gun to cut off the excess material.

[0102] Secure the cable assembly and use a thrust gauge to push the cable tie buckle axially.

[0103] Record the axial thrust (N) when the cable tie undergoes initial relative displacement with respect to the outer wall of the sleeve.

[0104] Test Item 4: Terminal Crimping Profile Morphology Scoring (Characterizing Blind Crimping Adaptability) Test objective: To evaluate the deformation and filling of the longitudinal structure inside the terminal.

[0105] Test steps: Transverse wire cutting was performed on the crimped terminal portion to prepare metallographic samples.

[0106] Observe the interior of the insulating layer crimped wing under a microscope.

[0107] Scoring rules: 5 points: The longitudinal ridge is completely collapsed and deformed, with no gaps visible to the naked eye, and the insulation layer is undamaged.

[0108] 3 points: There are tiny gaps, or insufficient longitudinal ridge deformation leading to slight deformation of the terminals.

[0109] 1 point: There is a through gap, the insulation layer is broken, or the terminal flap is not closed.

[0110] Test result data: The test data for each group of samples are summarized in Table 1 below.

[0111] Table 1. Summary of Performance Test Data for Connector Components Results Analysis and Conclusions: Based on the test data in Table 1 and the structural features of the aforementioned technical solutions, the following conclusions are drawn: Comparing the data of Example 1 (1.18N), Comparative Example 4 (5.94N), and Comparative Example 1 (3.65N) to the longitudinal welding ridge, it can be seen that the threading resistance of the present invention is significantly lower than that of adhesive bonding and hot stamping processes.

[0112] Mechanism Analysis: Insufficient joint rigidity formed by adhesive bonding and heat treatment causes radial collapse of the insulating sleeve under gravity, resulting in a large area of ​​the inner wall of the sleeve adhering to the surface of the conductive core. This increased contact area leads to a significant increase in friction. This invention utilizes a hardened longitudinal weld ridge (increasing Young's modulus and hardness) formed by ultrasonic welding to construct a rigid support structure for the sleeve, maintaining the roundness of the sleeve and the heat dissipation gap between the inner wall and the core. This transforms the contact mode from surface contact to line contact or point contact, thereby significantly reducing threading resistance.

[0113] Comparing the data of Example 1 (46.2N) and Comparative Example 3 (11.4N) to the contribution of the composite material hierarchical structure to the bundle stability, it can be seen that under the same clamping force, the axial anti-slip force of the present invention is about 4 times that of the all-PET material.

[0114] Mechanism Analysis: The outer surface of the all-PET tubing (C3) is smooth with a low coefficient of friction, which cannot provide sufficient static friction to resist axial loads. This invention utilizes the micro-roughened surface of the outer aramid material (Example 1) to create a mechanical interlocking effect with the binding wire, thereby improving the fixing reliability of subsequent processes without sacrificing the smoothness of the inner threading.

[0115] Comparing the data of Example 1 with Comparative Example 1 (breakdown) and Comparative Example 2 (large leakage current) to ensure insulation safety, it can be seen that the electrical insulation performance of the present invention is optimal.

[0116] Mechanism analysis: Braided tubing has physical pores that cannot prevent intermolecular migration; the hot stamping process causes the insulation film thickness at the overlap to decrease and the material to carbonize due to high-temperature heat conduction, resulting in a loss of pressure resistance. The ultrasonic welding of this invention confines energy to the overlap interface, using the local melting of the polyester layer to achieve a dense connection, which eliminates physical gaps while maintaining the thickness and dielectric strength of the insulation layer, ensuring high pressure resistance in water immersion environments.

[0117] The compressibility of the longitudinal ridge in adapting to the blind crimping process in Examples 1-4 all scored above 4 points, indicating that the longitudinal welding ridge did not negatively interfere with terminal closure. Mechanism analysis: Although the longitudinal welding ridge has the rigidity to support the tube body, under the impact of the terminal crimping machine's ton-level pressure, its polymer matrix undergoes forced plastic flow, which can fill the gap by conforming to the closing trajectory of the terminal flaps, thus achieving a reliable connection under the condition of no-alignment (blind crimping).

Claims

1. A connecting wire assembly with good insulation, comprising a conductive core (10) and an insulating sleeve (20) covering the outside of the conductive core (10), characterized in that, The insulating sleeve (20) is a prefabricated tubular component made by winding an insulating film and ultrasonic welding; The insulating sleeve (20) has a longitudinal welded ridge (21) extending along the axial direction on its wall. The longitudinal welded ridge (21) is formed by ultrasonic welding of the insulating film at the overlap. The conductive core (10) is inserted inside the insulating sleeve (20), and the end of the conductive core (10) extends out of the end face of the insulating sleeve (20).

2. The connecting wire assembly with good insulation according to claim 1, characterized in that, The insulating film is a composite material film, which exhibits an asymmetric hierarchical structure after being wound to form the insulating sleeve (20); The inner surface layer of the insulating sleeve (20) is made of polyester material and has a first coefficient of friction; The outer surface layer of the insulating sleeve (20) is made of aramid fiber and has a second coefficient of friction; Wherein, the first coefficient of friction is less than the second coefficient of friction.

3. The connecting wire assembly with good insulation according to claim 1, characterized in that, The hardness of the longitudinal welded ridge (21) is greater than the hardness of the non-welded area of ​​the insulating sleeve (20), thereby forming a rigid spine on the insulating sleeve (20). The insulating sleeve (20) maintains a cylindrical cross-sectional shape through the rigid spine, so that there is a gap between the inner wall of the insulating sleeve (20) and the conductive wire core (10).

4. The connecting wire assembly with good insulation according to claim 1, characterized in that, The connecting wire assembly also includes a terminal block (40) having an insulating layer crimp portion (42). The insulating layer crimping part (42) wraps around the end of the insulating sleeve (20), and the longitudinal welding ridge (21) of the insulating sleeve (20) is compressed and deformed under the wrapping force of the insulating layer crimping part (42), and is tightly attached to the inner surface of the insulating layer crimping part (42).

5. A connecting wire assembly with good insulation according to claim 1, characterized in that, The overlap width at the joint of the insulating film is less than 1.5 mm; The length of the conductive core (10) extending beyond the end face of the insulating sleeve (20) is between 0.5 mm and 2.0 mm.

6. A method for manufacturing a connector assembly with good insulation, characterized in that, Includes the following steps: Prefabricated sleeve forming steps: Provide an insulating film, roll it up and continuously weld the overlap by ultrasonic welding technology to make a prefabricated insulating sleeve (20) with longitudinal welding ridge (21). Conductive core (10) preparation steps: Provide conductive core (10) cut to a predetermined length; Insertion procedure: Insert the conductive core (10) through the prefabricated insulating sleeve (20) until the end of the conductive core (10) is exposed; Terminal crimping step: Crimping and fixing the exposed end of the conductive core (10) with terminals.

7. A method for manufacturing a connector assembly with good insulation according to claim 6, characterized in that, In the pre-formed sleeve molding step, the selected insulating film is a composite film with a polyester side and an aramid side. During the winding process, the polyester side is controlled to face the inside of the pre-made insulating sleeve (20), and the aramid side is controlled to face the outside of the pre-made insulating sleeve (20).

8. A method for manufacturing a connector assembly with good insulation according to claim 6, characterized in that, In the terminal crimping step, the terminal crimping and fixing includes: Radial pressure is applied to the insulating sleeve (20) using a terminal crimping die, so that the longitudinal welding ridge (21) is crushed and fitted into the terminal (40) regardless of its position in the circumferential direction.

9. A method for manufacturing a connector assembly with good insulation according to claim 6, characterized in that, It also includes the bundled wire binding step; The specific steps of the bundled wire binding step are as follows: multiple connecting wire assemblies that have completed terminal crimping are gathered together and the binding wire (50) is wrapped around the outside of the prefabricated insulating sleeve (20). The binding wire (50) is directly wrapped around and fastened to the outer surface layer of the prefabricated insulating sleeve (20), wherein the outer surface layer is an aramid material layer.

10. A method for manufacturing a connector assembly with good insulation according to claim 6, characterized in that, In the terminal crimping step, the axial position of the pre-made insulating sleeve (20) on the conductive core (10) is calibrated by a tooling fixture before crimping to control the exposed length of the end of the conductive core (10).

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