A super-fine multi-strand film-wrapped stranded wire and its manufacturing method

Abstract

The present invention discloses a manufacturing method for a super-fine and multi-strand film-coated stranded wire, which includes the following steps: Stranding 3,000 to 5,000 enameled single wires with a diameter of 0.02 mm to 0.03 mm into a round stranded wire; A self-adhesive layer is coated on the outer surface of each enameled single wire; Performing untwisting treatment on the round stranded wire to reduce or eliminate the torsional stress generated by the stranding of the enameled single wires; Performing square pressing and heat setting treatment on the round stranded wire: During the extrusion process, blowing high-temperature gas onto the round stranded wire so that each single wire is bonded and shaped to each other through the self-adhesive layer to obtain a rectangular wire; Coating the rectangular wire with a film, and baking the rectangular wire before the finished product is wound up, so that the single wires bonded together in the rectangular wire are de-bonded and dispersed to obtain a film-coated rectangular wire; Performing fine shaping processing on the film-coated rectangular wire through a shaping die. The present invention can effectively prevent phenomena such as enameled single wire breakage, wire twisting, excessive finished product resistance, film wear, and film tearing during the stranding, film coating, and square pressing processes of multi-strand ultra-fine wire materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of wire production, and particularly relates to an ultra-fine and multi-strand film-covered stranded wire and a manufacturing method thereof. Background Art

[0002] At present, round stranded wire, also known as Litz wire, is widely used in electronic components in high-frequency application fields such as high-frequency transformers and high-frequency coils. It is an electromagnetic wire formed by stranding multiple enameled single wires. Round stranded wire can effectively reduce the "skin effect" in high-frequency applications and reduce high-frequency current loss. Compared with a single-strand wire of the same cross-sectional area, round stranded wire can reduce impedance, increase conductivity, improve efficiency and reduce heat generation, and also has better flexibility.

[0003] For high-frequency inductance components used in charging piles, for future electric vehicles, the industry is developing technologies with charging powers up to 450 kW based on a voltage of 800 V. The most advanced electronic technologies make it possible to reach a voltage level of 1000 V. At this high voltage level, faster and more efficient charging is allowed. These development trends pose high requirements on the insulation ability of high-frequency Litz wire in the inductors and transformers of chargers. Compared with in-vehicle chargers, external DC chargers can provide higher charging powers because their available space is not restricted. The power of the vehicle is limited by the weight and space of components. However, after the round stranded wire is wound into a coil, its slot fill factor and space volume ratio are relatively low, which directly affects the performance of the coil, heat dissipation ability, and the volume and weight of the overall motor or transformer.

[0004] To overcome the problem of relatively low slot fill factor and space volume ratio, a rectangular wire design is proposed in the prior art, that is, the round stranded wire after being coated with a film is flattened into a rectangular wire. And for such wires with the same cross-sectional area, the more the number of conductor strands of the wire, the better its performance. However, in the actual manufacturing process, for ultra-fine and multi-strand wires (such as: the number of strands exceeds 3000, and the conductor diameter is less than or equal to 0.03 mm), enameled single wires are prone to breakage during the stranding process, and the more the number of strands, the more likely it is to cause stress concentration in the wire, resulting in wire twisting; when the rectangular wire needs to be flattened to a width-to-thickness ratio greater than 1.5, problems such as single wire breakage, film wear, and film tearing will also occur. Summary of the Invention

[0005] The purpose of the present invention is to provide a manufacturing method for an ultra-fine and multi-strand film-covered stranded wire, which can effectively prevent phenomena such as enameled single wire breakage, wire twisting, excessive finished product resistance, film wear, and film tearing during the stranding, film coating, and square pressing processes of multi-strand ultra-fine wires.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A manufacturing method for an ultra-fine and multi-strand film-covered stranded wire, which includes the following steps:

[0008] Step 1: Stranding 3,000 to 5,000 enameled single wires into a round stranded wire; wherein, the diameter of the conductor of each enameled single wire is 0.02 mm to 0.03 mm, and the outer surface of each enameled single wire is coated with a self-adhesive layer;

[0009] Step 2: Untwisting the round stranded wire to reduce or eliminate the torsional stress generated by the stranding of the enameled single wires;

[0010] Step 3: Square pressing and heat setting the round stranded wire: First, extruding the round stranded wire in the up and down directions through upper and lower pressing rollers, and then extruding the round stranded wire in the left and right directions through left and right pressing rollers; during the up and down extrusion and left and right extrusion processes, spray heads are respectively arranged at the rear sides of the upper and lower pressing rollers and the left and right pressing rollers to blow high-temperature gas to the round stranded wire, heating the round stranded wire to 130 °C to 180 °C, so that each single wire is bonded and shaped to each other through the self-adhesive layer to obtain a rectangular wire;

[0011] Step 4: Coating the rectangular wire and baking the rectangular wire before finished product take-up, heating to 120 °C to make the single wires bonded together in the rectangular wire unbond and disperse to obtain a film-coated rectangular wire;

[0012] Step 5: Performing sizing and fine processing on the film-coated rectangular wire through a sizing die to obtain a film-coated rectangular wire finished product with precise dimensions, completing the production of ultra-fine and multi-strand film-coated stranded wires.

[0013] As a preferred solution of the present invention, in Step 1, when paying off 3,000 to 5,000 enameled single wires, a constant tension pay-off stand and an inlet mesh plate perforation method are used for pay-off.

[0014] As a preferred solution of the present invention, in Step 1, each enameled single wire is untwisted before stranding 3,000 to 5,000 enameled single wires into a round stranded wire.

[0015] As a preferred solution of the present invention, in Step 1, the round stranded wire has a composite stranding structure.

[0016] As a preferred solution of the present invention, in Step 1, the single wire is sequentially provided with a conductor, an insulating layer, and a self-adhesive layer from the inside to the outside.

[0017] As a preferred solution of the present invention, the material of the self-adhesive layer is polyamide.

[0018] As a preferred solution of the present invention, the material of the conductor is one of copper, silver, aluminum, aluminum alloy, copper-clad aluminum, and tin-plated copper.

[0019] As a preferred solution of the present invention, the material of the insulating layer is one of polyurethane, polyesterimide, and polyamideimide.

[0020] As a preferred embodiment of the present invention, in the fourth step, the process used for the coating is winding coating; the material used for the coating is one of polyimide, polyethylene naphthalate, and polyethylene terephthalate.

[0021] In addition, the present invention also provides an ultra-fine multi-strand film-coated stranded wire, which is made by the manufacturing method of the ultra-fine multi-strand film-coated stranded wire described in the above items.

[0022] Implementing an ultra-fine multi-strand film-coated stranded wire and its manufacturing method provided by the embodiments of the present invention, compared with the prior art, the beneficial effects are as follows:

[0023] The manufacturing method of the ultra-fine multi-strand film-coated stranded wire of the present invention reduces or eliminates the torsional stress generated by the twisting of the enameled single wires due to stranding by performing a untwisting treatment on the round stranded wire before squaring the round stranded wire, effectively preventing the wire from twisting, preventing conductor fatigue or damage, improving the flexibility of the round stranded wire, making it easier to perform subsequent processing, and helping to maintain the tight stranding structure of the conductor, ensuring uniform resistance of the conductor, thereby improving the electrical performance; secondly, by coating a self-adhesive layer on the outer surface of the enameled single wire, using the heat-bonding characteristic of the self-adhesive layer, each single wire in the round stranded wire is bonded to each other during the extrusion process to form a shape, thereby further preventing the occurrence of breakage when the enameled single wire is squared; furthermore, since the coating process is set after the squaring process, the outer coating of the rectangular wire will not have problems such as wear and tear caused by extrusion; finally, heating the ultra-fine multi-strand film-coated stranded wire before the finished product is wound up, so that the single wires bonded together in the ultra-fine multi-strand film-coated stranded wire are de-bonded and dispersed to ensure the softness of the finished wire, which is more conducive to the subsequent processing of the wire; in addition, the present invention also performs fine shaping processing on the film-coated rectangular wire through a shaping die, ensuring the accuracy of the finished product size of the film-coated rectangular wire and improving the yield rate.

[0024] It should be noted that the ultra-fine multi-strand film-coated stranded wire produced by the manufacturing method of the present invention can meet the design requirements of electronic and electrical products with lower resistance, lower height, smaller volume, lighter weight, and higher power density, and is widely used in multiple fields such as electronics, electrical appliances, motors, network communication, smart home, new energy, automotive electronics, medical electronics, military electronics, and aerospace technology.

[0025] Under the same cross-sectional area, the ultra-fine multi-strand film-coated stranded wire produced by the manufacturing method of the present invention has a larger conductor cross-sectional area than the round stranded wire, further reducing the "skin effect", reducing high-frequency current loss, and being more suitable for high-frequency conduction work.

[0026] In the same winding space, the ultra-fine multi-strand film-coated stranded wire produced by the manufacturing method of the present invention can achieve a higher coil slot fill factor and space volume ratio, effectively reduce the resistance, allow a larger current to pass through, obtain a higher Q value, and be more suitable for working under high current loads.

[0027] The ultra-fine multi-strand film-coated stranded wire produced by applying the manufacturing method of the present invention has a simple structure, good heat dissipation performance, stable performance, and good consistency; it can still maintain good temperature rise current and saturation current in high-frequency and high-temperature environments; it has strong anti-electromagnetic interference (EMI), small vibration, low noise, and can be installed at high density. Specific embodiments

[0028] The following combines examples to further describe in detail the specific embodiments of the present invention. The following examples are used to illustrate the present invention but not to limit the scope of the present invention.

[0029] A preferred embodiment of the present invention provides a manufacturing method for an ultra-fine multi-strand film-coated stranded wire, which includes the following steps:

[0030] Step 1: Stranding 3000 to 5000 enameled single wires into a round stranded wire; wherein, the diameter of the conductor of each enameled single wire is 0.02 mm to 0.03 mm, and a self-adhesive layer is coated on the outer surface of each enameled single wire.

[0031] Step 2: Perform untwisting treatment on the round stranded wire to reduce or eliminate the torsional stress generated by the stranding of the enameled single wires.

[0032] Step 3: Perform square pressing and heat setting treatment on the round stranded wire: first, extrude the round stranded wire in the up and down directions through upper and lower pressing rollers, and then extrude the round stranded wire in the left and right directions through left and right pressing rollers; during the up and down extrusion and left and right extrusion processes, spray heads are respectively arranged behind the upper and lower pressing rollers and the left and right pressing rollers to blow high-temperature gas to the round stranded wire, heating the round stranded wire to 130 °C to 180 °C, so that each single wire is bonded and shaped to each other through the self-adhesive layer to obtain a rectangular wire.

[0033] Step 4: Coating the rectangular wire, and baking the rectangular wire before the finished product is wound, heating it to 120 °C to make the single wires bonded together in the rectangular wire unbond and disperse, obtaining a film-coated rectangular wire.

[0034] Step 5: Perform fine shaping processing on the film-coated rectangular wire through a shaping die to obtain a film-coated rectangular wire finished product with precise dimensions, completing the production of the ultra-fine multi-strand film-coated stranded wire.

[0035] Thus, according to the manufacturing method of the ultra-fine and multi-strand film-coated stranded wire of the embodiments of the present invention, before squaring the round stranded wire, the round stranded wire is untwisted to reduce or eliminate the torsional stress generated by the stranding of the enameled single wire, effectively preventing conductor fatigue or damage, improving the flexibility of the round stranded wire, making it easier to carry out subsequent processing, and helping to maintain the tight stranding structure of the conductor, ensuring the uniform resistance of the conductor, thereby improving the electrical performance; secondly, by coating a self-adhesive layer on the outer surface of the enameled single wire, using the heat-bonding property of the self-adhesive layer, each single wire in the round stranded wire is bonded to each other during the extrusion process to form a shape, thereby further preventing the occurrence of fracture when the enameled single wire is formed into a square shape; furthermore, since the film coating process is set after the squaring process, the outer film coating of the rectangular wire will not have problems such as wear and tear caused by extrusion; finally, before the finished product is wound up, the ultra-fine and multi-strand film-coated stranded wire is heated to make the single wires bonded together in the ultra-fine and multi-strand film-coated stranded wire untie and disperse, so as to ensure the softness of the finished wire material, which is more conducive to the subsequent processing of the wire material; in addition, the present invention also performs fine shaping processing on the film-coated rectangular wire through a shaping die, ensuring the accuracy of the finished product size of the film-coated rectangular wire and improving the yield rate.

[0036] It should be noted that the ultra-fine and multi-strand film-coated stranded wire manufactured by the manufacturing method of the present invention can meet the design requirements of electronic and electrical products with lower height, smaller volume, lighter weight, and higher power density, and is widely used in many fields such as electronics, electrical appliances, electric motors, network communication, smart home, new energy, automotive electronics, medical electronics, military electronics, and aerospace technology.

[0037] Under the same cross-sectional area, the ultra-fine and multi-strand film-coated stranded wire manufactured by the manufacturing method of the present invention has a larger conductor cross-sectional area than the round stranded wire, further reducing the "skin effect", reducing high-frequency current loss, and being more suitable for high-frequency conduction work.

[0038] In the same winding space, the ultra-fine and multi-strand film-coated stranded wire manufactured by the manufacturing method of the present invention can make the coil slot fill factor and space volume ratio higher, effectively reduce the resistance, pass a larger current, obtain a higher Q value, and be more suitable for high-current load work.

[0039] The ultra-fine and multi-strand film-coated stranded wire manufactured by applying the manufacturing method of the present invention has a simple structure, good heat dissipation performance, stable performance, and good consistency; it can still maintain good temperature rise current and saturation current in high-frequency and high-temperature environments; it has strong anti-electromagnetic interference (EMI), small vibration, low noise, and can be installed at high density.

[0040] Exemplarily, in step one, when 3,000 to 5,000 strands of enameled single wire are paid out, a constant tension pay-off stand and a wire-inlet mesh perforation method are used for pay-off. Among them, the constant tension pay-off stand is a device used to control the material tension during the pay-off process, which is composed of a pay-off wheel, a drive system, and a braking system, and can ensure that the wire is released with uniform tension; the wire-inlet mesh perforation generally refers to a method of guiding the wire through the holes on the mesh to ensure that the wire moves in the correct direction and path, and prevent the wire from being damaged by friction or impact during movement. Therefore, such a design can effectively solve the problem of wire breakage when ultra-fine (diameter 0.02mm to 0.03mm) enameled single wires are twisted.

[0041] For example, considering that the enameled single wire may twist itself during transportation and generate torsional stress, in order to minimize the internal stress of the wire, in step one, each enameled single wire needs to be detwisted before twisting 3000 to 5000 strands of enameled single wire into round stranded wire.

[0042] Exemplarily, in step 1, the round stranded wire is preferably a double-twisted structure (ie, the inner and outer layers are wound in opposite directions), which can effectively prevent the round stranded wire from loosening due to subsequent extrusion and ensure the tightness between the single wires.

[0043] Exemplarily, in the step 1, the single wire is provided with a conductor, an insulating layer and a self-adhesive layer from the inside to the outside. In this embodiment, the material of the conductor is one of copper, silver, aluminum, aluminum alloy, copper-clad aluminum and tinned copper. The material of the self-adhesive layer is preferably polyamide, commonly known as nylon, which is a type of thermoplastic polymer with excellent strength, toughness, heat resistance and chemical resistance. The main components of polyamide used in self-adhesive paint are nylon 6, nylon 66, etc., which mainly play the role of heat bonding and then softening and debonding. In other words, it will soften when heated, and its bonding performance will increase due to the increased movement of the molecular chain; at 130 degrees Celsius to 180 degrees Celsius, polyamide can achieve a better bonding state, so that the adhesion is increased and the bonding effect is improved. In addition, polyamide has begun to degrade when it is heated to 120 degrees Celsius for the second time. Due to insufficient thermal stability, its performance has decreased, and the adhesion has decreased accordingly, which promotes the debonding and debonding of the bonded single wires. The material of the insulating layer is one of polyurethane, polyesterimide and polyamideimide. The insulating layer increases the rigidity and stability of the single wire, provides independent electrical isolation for each conductor, prevents current leakage between adjacent conductors, thereby avoiding short circuits and crosstalk; and can protect the conductors from friction and wear during the twisting and extrusion processes, and can also prevent the conductors from being corroded by corrosive chemicals, thereby extending the service life of the wire.

[0044] Exemplarily, in the fourth step, the process for encapsulation is winding encapsulation; the material used for encapsulation is one of polyimide, polyethylene naphthalate, and polyethylene terephthalate, so as to improve the overall performance and reliability of the wire and meet the diverse requirements in electrical engineering.

[0045] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0046] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the technical principle of the present invention, several improvements and replacements can still be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. A manufacturing method of an ultra-fine multi-strand film-wrapped stranded wire, characterized in that, The steps are as follows: Step 1: First, perform untwisting treatment on each enameled single wire; then stranding 3,000 to 5,000 enameled single wires into a round stranded wire; wherein, the diameter of the conductor of each enameled single wire is 0.02 mm to 0.03 mm, and the outer surface of each enameled single wire is coated with a self-adhesive layer; the material of the self-adhesive layer is polyamide; Step 2: Perform untwisting treatment on the round stranded wire to reduce or eliminate the torsional stress generated by the stranding of the enameled single wires; Step 3: Perform square pressing and heat setting treatment on the round stranded wire: First, extrude the round stranded wire in the up and down directions through upper and lower pressing rollers, and then extrude the round stranded wire in the left and right directions through left and right pressing rollers; during the up and down extrusion and left and right extrusion processes, spray heads are respectively arranged at the rear sides of the upper and lower pressing rollers and the left and right pressing rollers to blow high-temperature gas to the round stranded wire, heating the round stranded wire to 130 °C to 180 °C, so that each single wire is bonded and shaped to each other through the self-adhesive layer to obtain a rectangular wire; Step 4: Perform film coating on the rectangular wire, and bake the rectangular wire before finished product winding, heating to 120 °C to make the single wires bonded together in the rectangular wire untie and disperse, obtaining a film-coated rectangular wire; Step 5: Perform fine shaping processing on the film-coated rectangular wire through a shaping die to obtain a film-coated rectangular wire finished product with precise dimensions, completing the production of the ultra-fine and super-multi-strand film-coated stranded wire.

2. The manufacturing method of the ultra-fine multi-strand film-wrapped stranded wire according to claim 1, characterized in that In the said Step 1, when stranding 3,000 to 5,000 enameled single wires, a constant tension pay-off stand and the perforation method of an inlet mesh plate are used for pay-off.

3. The manufacturing method of the ultra-fine multi-strand film-covered stranded wire according to claim 1, characterized in that, In the said Step 1, the round stranded wire is of a composite stranding structure.

4. The manufacturing method of the ultra-fine multi-strand film-wrapped stranded wire according to claim 1, characterized in that, In the said Step 1, the single wire is successively provided with a conductor, an insulating layer, and a self-adhesive layer from the inside to the outside.

5. The manufacturing method of the super-fine multi-strand film-wrapped stranded wire according to claim 4, characterized in that, The material of the conductor is one of copper, silver, aluminum, aluminum alloy, copper-clad aluminum, and tin-plated copper.

6. The manufacturing method of the superfine multi-strand film-covered stranded wire according to claim 4, characterized in that, The material of the insulating layer is one of polyurethane, polyesterimide, and polyamideimide.

7. The manufacturing method of the ultra-fine multi-strand film-coated stranded wire according to claim 1, characterized in that, In the said Step 4, the process adopted for film coating is winding film coating; the material adopted for film coating is one of polyimide, polyethylene naphthalate, and polyethylene terephthalate.

8. A super-fine and multi-strand film-wrapped stranded wire, characterized in that, It is made by the manufacturing method of the ultra-fine and super-multi-strand film-coated stranded wire according to any one of claims 1 to 7.