Polyimide electromagnetic flat wire preparation device and method
The device addresses adhesion and pore issues in polyimide electromagnetic flat wire production by preheating and using exhaust holes to reduce air intake, achieving improved insulation and simplified production.
Patent Information
- Application Number
- CN202411260774.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2024-12-13
AI Technical Summary
Existing methods for preparing polyimide electromagnetic flat wires face issues of insufficient adhesion of the insulation layer and the presence of pores, which affect the insulation performance and quality, while being complex and costly due to the need for multiple process steps and equipment.
A device comprising a preheating unit, extrusion unit with exhaust holes, and a straightening unit is used to preheat the conductor to match the extrusion temperature, control the temperature difference, and utilize negative pressure to reduce air intake, ensuring uniform coating and adhesion of the polyimide insulation layer.
The solution improves adhesion of the insulation layer and reduces pores, resulting in a smoother, higher-quality electromagnetic flat wire with enhanced insulation performance and simplified production processes.
Smart Images
Figure CN119116316A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field related to a device and method for preparing an electromagnetic wire, and in particular to a device and method for preparing a polyimide electromagnetic flat wire. Background Art
[0002] Electromagnetic wire is an insulated wire used to make coils or windings in electrical products. It is formed by coating an insulating layer on a conductor (such as copper wire) and is mainly used in motors, electrical appliances, instruments, transformers, etc. Common electromagnetic wires are divided into round wires and flat wires according to the different wire specifications. The slot fill rate of flat wires is about 30% higher than that of round wires. Under the premise of unchanged space, more copper wires can be filled to generate stronger magnetic field strength and improve power density.
[0003] However, during the coating process, the insulating paint of electromagnetic flat wire will shrink unevenly due to the surface tension of the liquid, which is easy to deform, resulting in thinning of the four corners and affecting the insulation. It is necessary to improve the coating thickness at the R corner. On the other hand, it is difficult to coat the paint film at the R corner of the flat wire, and it is difficult to ensure the uniformity of the insulation layer. After the flat wire is bent, the stress is concentrated at the R corner, which is easy to cause damage to the coating layer. Therefore, the accuracy and quality requirements of the copper wire and its coating are very high. It can be seen that the traditional process of using the traditional insulating paint coating + baking (repeatedly) to produce electromagnetic flat wire is not only complicated and difficult to operate, but also the quality of the finished product is not high, especially the uneven paint film leads to low insulation strength, which makes the PDIV (partial discharge initiation voltage) value not high. Therefore, the traditional insulating paint coating + baking process is not a good process choice for the preparation of electromagnetic flat wire.
[0004] Tongling Jingda Special Electromagnetic Wire Co., Ltd. has proposed a processing technology for PEEK electromagnetic wire (application number: 202010228659.8), the main processing flow is painting → baking → extrusion. The painting and baking processes directly use the existing enameled wire production line and processing technology, and the extrusion process is directly cooled and formed after one coating. With the introduction of extrusion technology into the preparation of electromagnetic wire, the problem of uneven paint film of electromagnetic flat wire in traditional processes has been effectively solved.
[0005] In addition, Jiateng Electric (Ganzhou) Co., Ltd. proposed an insulated wire and its preparation method, coil and electronic / electrical equipment (application number: 202410851553.1). The patent uses an extrusion process to extrude thermoplastic polyimide (PI material) to form an insulating layer on the core material, which can significantly improve production efficiency compared to the traditional multiple coating process; by optimizing the preparation process of the adhesive layer and the extrusion process of the insulating layer, a specific adhesive layer formula is used to prepare the adhesive layer, and then the insulating layer is extruded under specific negative pressure conditions, so that the prepared thermoplastic polyimide insulating layer has fewer bubbles and the bubble size is also smaller, ensuring that the insulating layer has a higher breakdown voltage.
[0006] However, although the problem of uneven paint film of electromagnetic flat wire can be solved by coating the insulating layer on the conductor through the extrusion process, it also faces the problem of insufficient adhesion of the insulating layer. As an important parameter of electromagnetic wire, the adhesion of the insulating layer directly affects the insulation performance of the electromagnetic wire. Therefore, when using the extrusion process to prepare electromagnetic wire, how to improve the adhesion of the insulating layer is the first problem that needs to be solved.
[0007] Tongling Jingda Special Electromagnetic Wire Co., Ltd. adopts a combination of paint film + extrusion coating, taking advantage of the advantages of the two processes to solve the problems of uneven paint film and insufficient adhesion to a certain extent. Jiateng Electric (Ganzhou) Co., Ltd. prepared an adhesive layer on the wire before the extrusion process to improve the adhesion of thermoplastic polyimide. However, whether it is Tongling Jingda Special Electromagnetic Wire Co., Ltd. or Jiateng Electric (Ganzhou) Co., Ltd., the preparation process they adopt uses a variety of process superposition methods compared to traditional processes. The entire preparation process is cumbersome, the procedures are complicated, and there are many equipment involved, which leads to an increase in overall production energy consumption. It is only suitable for large-scale operations and it is not easy to change specifications.
[0008] In addition, in the extrusion process, another major factor affecting the adhesion of the insulating layer is that the temperature difference between the insulating layer and the metal conductor should not be too large during the process of coating the insulating layer on the surface of the metal conductor. In other words, it is necessary to preheat the metal conductor before the extrusion process. If the metal conductor is not preheated, when the metal conductor enters the extruder and comes into contact with the high-temperature rubber, the metal conductor will exchange heat with the rubber, and the rubber close to the surface of the metal conductor will cool down and shrink rapidly, resulting in a significant reduction in the adhesion between the rubber and the metal conductor, and even the phenomenon of separation from the metal conductor.
[0009] The preparation process used by Tongling Jingda Special Electromagnetic Wire Co., Ltd. does not preheat the conductor before the extrusion step. Therefore, the adhesion between the insulation layer and the paint film cannot meet expectations, which may cause the insulation layer and the conductor paint film to separate. The preparation process used by Jiateng Electric (Ganzhou) Co., Ltd., although there is a step of preheating the core material to 200-320°C during the extrusion process, there is still a large difference between the preheating temperature and the actual extrusion temperature. In addition, when the core material after preheating enters the extruder, if the distance in the middle is large, there will be a large amount of heat loss, which will further increase the temperature difference between the core material and the rubber, increase the heat exchange between the two, and reduce the adhesion of the final insulation layer.
[0010] At the same time, the use of extrusion technology to prepare electromagnetic wires also requires solving the problem of bubbles in the insulation layer. The preparation process adopted by Jiateng Electric (Ganzhou) Co., Ltd. is to evacuate the extruder before the extrusion process to reduce the contact between oxygen and the material, and avoid the reaction between the material and oxygen to produce small molecular gases. However, since the wire inlet and outlet of the extruder are always in an open state, in order to ensure that the extruder can achieve the expected vacuum effect, the entire equipment needs to be placed in a sealed environment for the vacuum step, which will greatly increase the production cost. In actual production, it is difficult to implement this method to ensure the vacuum environment of the extruder. Moreover, even if this vacuuming method is adopted, it is difficult to discharge the air between the rubber particles entering the hopper and the barrel, and the air between the rubber particles will also be difficult to discharge from the extruder, so that after the extrusion process is completed, tiny pores will still be produced in the insulation layer, resulting in quality defects. Summary of the invention
[0011] The object of the present invention is to provide a polyimide electromagnetic flat wire preparation device and method, aiming to solve the problems of insufficient adhesion of the electromagnetic flat wire insulation layer and the presence of pores in the insulation layer by using a simpler device and operation method.
[0012] In order to solve the above technical problems, the present invention provides a polyimide electromagnetic flat wire preparation device, including an extrusion device, a preheating device, and a straightening device. The polyimide electromagnetic flat wire includes a conductor and a polyimide insulation layer coated on the surface of the conductor; the extrusion device includes a screw barrel, a hopper and a head; the screw barrel is provided with a first exhaust hole, and the first exhaust hole is used to discharge the gas generated in the extrusion process.
[0013] Furthermore, there are a plurality of first exhaust holes which are evenly distributed on the screw barrel, and the first exhaust holes are connected to a negative pressure device.
[0014] Furthermore, the hopper is arranged at one end of the screw barrel, and the hopper includes a material holding section and a connecting section, the material holding section is used to hold polyimide particles, and the connecting section is used to connect the material holding section and the screw barrel; the connecting section is provided with an anti-blocking metering device, and the anti-blocking metering device includes a feeding gear and a reduction motor, the feeding gear is driven by the reduction motor, and the reduction motor and the feeding gear can control the polyimide particles to enter the screw barrel at a preset rate.
[0015] Furthermore, the connecting section is provided with a second exhaust hole, and the second exhaust hole is used to exhaust excess air during the feeding process; there are a plurality of second exhaust holes, which are evenly distributed on the connecting section, and the second exhaust holes are connected to a negative pressure device.
[0016] Furthermore, the die head is arranged at one end of the screw barrel away from the hopper, and the die head includes a wire inlet and a wire outlet.
[0017] Furthermore, the preheating device is connected to one end of the straightening device, and the other end of the straightening device is connected to the wire inlet of the machine head. After being preheated by the preheating device, the wire enters the straightening device for straightening, and the straightened wire enters the machine head from the wire inlet of the machine head.
[0018] Furthermore, the preheating device includes a heating element, which is used to heat the wire in the preheating device to a preset temperature; the preheating device is provided with a protective gas inlet for introducing a protective gas, and the protective gas is used to prevent the wire from being oxidized during the preheating process.
[0019] Furthermore, the preset temperature is 370°C-440°C.
[0020] Furthermore, the distance between one end of the straightening device connected to the preheating device and one end connected to the wire inlet of the machine head is no more than 15 mm.
[0021] Furthermore, a heat-insulating structure is provided on the outer periphery of the straightening device, and the heat-insulating structure is used to reduce heat loss of the wire when passing through the straightening device.
[0022] In addition, the present invention also provides a method for preparing polyimide electromagnetic flat wire using the above-mentioned polyimide electromagnetic flat wire preparation device, comprising the following steps:
[0023] S1: Preheating the wire: introducing the prepared wire into the preheating device for preheating, the preheating temperature is 370°C-440°C;
[0024] S2: Wire straightening: introducing the preheated wire into the straightening device for straightening, and introducing the straightened wire into the handpiece through the wire inlet of the handpiece;
[0025] S3: extrusion of polyimide insulation layer: the polyimide particles enter the screw barrel through the hopper for melt extrusion and enter the die. Inside the die, the extruded polyimide material coats the wire to form a uniform polyimide insulation layer on the outer surface of the wire. The wire coated with the polyimide insulation layer is led out through the wire outlet of the die.
[0026] S4: Cooling and coiling: A cooling system cools the wire coated with the polyimide insulation layer that is led out through the wire outlet of the machine head, and coils it through a coiling device to form a final electromagnetic flat wire product.
[0027] Furthermore, in step S3, the melting temperature of the polyimide particles is adapted to the preheating temperature of the wire in step S1 and is set to 370°C-440°C.
[0028] Furthermore, in step S3, during the entire feeding and extrusion process, the first exhaust hole and the second exhaust hole are respectively connected through an external negative pressure device to timely exhaust the gas in the feeding and extrusion processes.
[0029] Furthermore, in step S3, the polyimide particles are first dried before entering the hopper, and the drying process refers to drying at 200° C. for not less than 8 hours.
[0030] Furthermore, in step S1, before the preheating of the wire, the wire is unwound through a unwinding device, and sequentially passes through the preheating device, the straightening device, the machine head and the cooling system to be connected to the winding device, and the pre-tensioning of the wire before the preparation of the polyimide electromagnetic flat wire is achieved through a tension control system.
[0031] Implementing the embodiments of the present invention will have the following beneficial effects:
[0032] 1. The present application preheats the conductor, and the conductor preheating temperature is matched with the extrusion temperature of the polyimide particles, that is, the temperature is set within the range of 370°C-440°C, so that the temperature difference between the outer surface of the conductor after preheating and the extruded polyimide material is small, and the polyimide material close to the conductor surface will not cool and shrink rapidly, which greatly improves the overmolding effect and effectively improves the adhesion of the polyimide insulation layer; in addition, by controlling the length of the straightening device located between the preheating device and the machine head to within 15 mm, and providing an insulation structure on the periphery of the straightening device, the preheated conductor can enter the machine head faster, reducing the heat loss of the conductor before entering the machine head, further reducing the temperature difference between the outer surface of the conductor and the extruded polyimide material, and improving the adhesion of the polyimide insulation layer.
[0033] 2. During the unloading process, even if the polyimide raw material is vacuumed and sealed and transferred to the hopper, there is still a small amount of air between the polyimide particles. When the material is accumulated in the hopper, it is difficult for the air between the polyimide particles to escape upward, so it will enter the screw barrel with the polyimide particles. This application sets a unloading gear in the connecting section of the hopper and drives it through a reduction motor. On the one hand, it can achieve uniform and metered unloading of polyimide particles and prevent material accumulation during the unloading process. On the other hand, due to the rotation of the unloading gear, the polyimide particles in the hopper are always in a dynamic motion state. A small amount of air between the polyimide particles will partially escape from the hopper upward, reducing the amount of air entering the screw barrel, thereby reducing the number of pores in the insulating layer.
[0034] 3. The present application evenly arranges exhaust holes on the connecting section of the hopper and the screw barrel, and connects them through an external negative pressure device. During the entire feeding and extrusion process, exhaust is continuously discharged to the outside, and the gas entering the connecting section and the screw barrel can be discharged in sections, further reducing the amount of air in the screw barrel, greatly reducing the size and number of pores in the insulating layer, reducing the flaws and defects on the surface of the insulating layer, making the surface of the formed electromagnetic flat wire smoother and more uniform, and improving the appearance quality. At the same time, the high-density insulating layer can be more tightly filled around the conductor, which helps to better combine the insulating layer and the conductor and enhance the adhesion between the insulating layer and the conductor. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0036] Figure 1 This is a schematic structural diagram of an extrusion device according to an embodiment of the present invention;
[0037] Figure 2 It is an overall schematic diagram of the electromagnetic flat wire preparation device according to an embodiment of the present invention;
[0038] Figure 3 This is a schematic diagram of an anti-blocking metering device according to an embodiment of the present invention;
[0039] Figure 4 This is a flow chart of the method for preparing electromagnetic flat wire according to an embodiment of the present invention.
[0040] Among them: 1. Hopper; 2. Screw barrel; 3. Machine head; 4. First exhaust hole; 5. Second exhaust hole; 6. Wire outlet; 7. Preheating device; 8. Heating element; 9. Protective gas inlet; 10. Straightening device; 11. Unloading gear; 12. Reducer motor. DETAILED DESCRIPTION
[0041] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.
[0042] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.
[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0044] Please refer to Figure 1-Figure 4 The embodiment of the present invention provides a polyimide electromagnetic flat wire preparation device, including an extrusion device, a preheating device 7, and a straightening device 10. The polyimide electromagnetic flat wire includes a conductor and a polyimide insulation layer coated on the surface of the conductor; the extrusion device includes a screw barrel 2, a hopper 1 and a head 3; the screw barrel 2 is provided with a first exhaust hole 4, and the first exhaust hole 4 is used to discharge the gas generated in the extrusion process.
[0045] In a possible implementation, the wire is a metal wire, preferably a copper wire or an aluminum wire.
[0046] In a possible implementation, there are a plurality of first exhaust holes 4 evenly distributed on the screw barrel 2, and the first exhaust holes 4 are connected to a negative pressure device or a vacuum device (not shown in the figure). Preferably, the first exhaust holes 4 are evenly arranged in the axial direction and circumferential direction of the screw barrel 2.
[0047] By arranging a first exhaust hole 4 on the screw barrel 2 and connecting it through an external negative pressure device or a vacuum device, the gas is continuously exhausted to the outside during the entire extrusion process, so that the gas in the screw barrel can be discharged in time, further reducing the amount of air in the screw barrel 2, greatly reducing the size and number of pores in the insulating layer, reducing the flaws and quality defects on the surface of the insulating layer, making the surface of the formed electromagnetic flat wire smoother and more uniform, and improving the appearance quality. At the same time, the high-density insulating layer can be more tightly filled around the conductor, which helps to better combine the insulating layer and the conductor and enhance the adhesion between the insulating layer and the conductor.
[0048] In a possible implementation, a heating unit (not shown) is provided on the screw barrel 2, and the heating unit is evenly arranged along the axial direction and circumferential direction of the screw barrel 2. The heating unit is used to heat the polyimide particles in the screw barrel 2 into a molten fluid state, and the heating temperature is controlled between 370°C and 440°C. The molten polyimide particles are continuously transported to the front of the screw, and enter the die head for molding through the filter screen and the diverter plate.
[0049] In a possible implementation, the hopper 1 is disposed at one end of the screw barrel 2, and the hopper 1 includes a material holding section and a connecting section, the material holding section is used to hold polyimide particles, and the connecting section is used to connect the material holding section and the screw barrel. The connecting section is provided with an anti-blocking metering device, and the anti-blocking metering device includes a feeder gear 11 and a reduction motor 12, the feeder gear 11 is driven by the reduction motor 12, and the reduction motor 12 and the feeder gear 11 can control the polyimide particles to enter the screw barrel 2 at a preset rate.
[0050] By setting an anti-blocking metering device at the connection section of the hopper, on the one hand, the uniform and metered feeding of polyimide particles can be achieved to prevent material accumulation during the feeding process. On the other hand, due to the rotation of the feeding gear 11, the polyimide particles in the hopper 1 are always in a dynamic motion state, and a small amount of air between the polyimide particles will partially escape from the hopper upward, reducing the amount of air entering the screw barrel 2, thereby reducing the number of pores in the insulating layer. This also means that the present solution does not require the polyimide particle material to be pre-vacuumed and sealed and transferred to the hopper for feeding, which greatly reduces the difficulty of operation, simplifies the production process, and reduces production costs.
[0051] At the same time, by the rotation of the unloading gear 11, the polyimide particles that are bonded into a mass can be prevented from directly entering the screw barrel 2, causing blockage and material interruption, which is not conducive to the uniform and continuous melt extrusion of the polyimide material. The bonding of polyimide particles into a mass is largely caused by insufficient drying. Therefore, this scheme allows the polyimide particles to be bonded into a mass for unloading to a certain extent, which also means that this scheme puts forward lower requirements for the drying treatment before unloading the polyimide particles, and even for the situation where the dryness of the raw materials of the polyimide particles is not bad (there is no obvious caking situation), it can be exempted from the drying treatment and directly unloaded, which further simplifies the production process and reduces production costs.
[0052] In a possible embodiment, the reduction motor 12 is controlled by a control unit, and the control unit determines the feeding rate of the polyimide particles according to product parameters (such as wire type, wire diameter, wire feeding speed, thickness of the insulation layer after molding, etc.), and then obtains the rotation rate of the feeding gear 11 and the output power of the reduction motor 12.
[0053] In a possible implementation, a photoelectric sensor is provided at the lower inner part of the material holding section, and an audible and visual alarm is provided at the upper outer part of the material holding section, and the photoelectric sensor and the audible and visual alarm are in communication connection with the control unit. The photoelectric sensor is used to detect whether the polyimide material in the material holding section is lower than the lowest line of material unloading, and when the polyimide material in the material holding section is lower than the lowest line, the audible and visual alarm sounds an alarm, indicating that polyimide material needs to be added to prevent interruption of unloading.
[0054] It is necessary to set the photoelectric sensor and the sound and light alarm on the material holding section. Since the present solution does not carry out the unloading and extrusion process in a completely sealed environment, when the polyimide particles in the material holding section are unloaded but the polyimide material is not added in time, a large amount of air will enter the screw barrel from the hopper. The air that is not discharged through the exhaust hole in time will form pores inside and on the surface of the insulation layer, affecting the final molding quality.
[0055] In a possible implementation, the connecting section is provided with a second exhaust hole 5, and the second exhaust hole 5 is used to exhaust excess air during the material feeding process; there are a plurality of second exhaust holes 5, which are evenly distributed on the connecting section, and the second exhaust holes 5 are connected to a negative pressure device or a vacuum device (not shown in the figure), and the negative pressure device or the vacuum device can be shared with the first exhaust hole 4. Preferably, the second exhaust holes 5 are evenly arranged in the axial direction and circumferential direction of the connecting section.
[0056] By setting a second exhaust hole 5 at the connecting section of the hopper 1 and connecting it through an external negative pressure device or a vacuum device, during the entire feeding process, the air that does not have time to escape upward can be discharged through the second exhaust hole 5, further reducing the amount of air entering the screw barrel 2, greatly reducing the size and number of pores in the insulating layer, reducing the flaws and defects on the surface of the insulating layer, making the surface of the formed electromagnetic flat wire smoother and more uniform, and improving the appearance quality. At the same time, the high-density insulating layer can be filled more tightly around the conductor, which helps to better combine the insulating layer and the conductor and enhance the adhesion between the insulating layer and the conductor.
[0057] In a possible implementation manner, the head 3 is disposed at an end of the screw barrel 2 away from the hopper 1 , and the head 3 includes a wire inlet and a wire outlet 6 .
[0058] In a possible embodiment, the preheating device 7 is connected to one end of the straightening device 10, and the other end of the straightening device 10 is connected to the wire inlet of the head 3. After being preheated by the preheating device 7, the wire enters the straightening device 10 for straightening. After being straightened, the wire enters the head 3 from the wire inlet of the head 3.
[0059] In a possible embodiment, the preheating device 7 includes a heating element 8, which is used to heat the wire in the preheating device 7 to a preset temperature, and the preset temperature is 370°C-440°C; the preheating device 7 is provided with a protective gas inlet 9 for introducing a protective gas, and the protective gas is used to prevent the wire from being oxidized during the preheating process.
[0060] In a possible implementation manner, the distance between one end of the straightening device 10 connected to the preheating device 7 and one end connected to the wire inlet of the handpiece 3 is no more than 15 mm.
[0061] In a possible implementation manner, a heat-insulating structure (not shown in the figure) is disposed on the outer periphery of the straightening device 10 , and the heat-insulating structure is used to reduce heat loss of the wire when passing through the straightening device 10 .
[0062] By controlling the length of the straightening device 10 located between the preheating device 7 and the head 3 to within 15 mm, and providing a heat preservation structure on the periphery of the straightening device 10, the preheated wire can enter the head 3 faster, thereby reducing the heat loss of the wire before entering the head 3, further reducing the temperature difference between the outer surface of the wire and the extruded polyimide material, and improving the adhesion of the polyimide insulation layer.
[0063] By setting the preheating temperature of the conductor to match the extrusion temperature, the temperature difference between the outer surface of the conductor after preheating and the extruded polyimide material is small, and the polyimide material close to the conductor surface will not cool and shrink rapidly, thereby improving the overmolding effect and effectively improving the adhesion of the polyimide insulation layer.
[0064] In addition, the present invention also provides a method for preparing polyimide electromagnetic flat wire using the above-mentioned polyimide electromagnetic flat wire preparation device, comprising the following steps:
[0065] S1: Preheating the wire: introducing the prepared wire into the preheating device 7 for preheating, the preheating temperature is 370°C-440°C;
[0066] S2: Wire straightening: the preheated wire is introduced into the straightening device 10 for straightening, and the straightened wire is introduced into the handpiece 3 through the wire inlet of the handpiece 3;
[0067] S3: extrusion of polyimide insulation layer: the polyimide particles enter the screw barrel 2 through the hopper 1 for melt extrusion, and enter the die 3. Inside the die 3, the extruded polyimide material coats the wire, forming a polyimide insulation layer on the outer surface of the wire. The wire coated with the polyimide insulation layer is led out through the wire outlet 6 of the die 3.
[0068] S4: Cooling and coiling: A cooling system cools the wire coated with the polyimide insulation layer that is led out through the wire outlet 6 of the machine head 3, and coils it through a coiling device to form a final electromagnetic flat wire product.
[0069] In a possible implementation, in step S3, the melting temperature of the polyimide particles is adapted to the preheating temperature of the wire in step S1, and is set to 370°C-440°C.
[0070] In a possible implementation, in step S3, during the entire feeding and extrusion process, the first exhaust hole 4 and the second exhaust hole 5 are respectively connected through an external negative pressure device or a vacuum device to timely exhaust the gas in the feeding and extrusion processes.
[0071] In a possible implementation, in step S3, the polyimide particles are first dried before entering the hopper 1, and the drying process refers to drying at 200°C for not less than 8 hours.
[0072] In a possible implementation, in step S1, before the preheating of the wire, the wire is unwound through an unwinding device, and sequentially passes through the preheating device 7, the straightening device 10, the head 3 and the cooling system to be connected to the winding device, and the pre-tensioning of the wire before the preparation of the polyimide electromagnetic flat wire is achieved through a tension control system.
[0073] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.
Claims
1. A polyimide electromagnetic flat wire preparation device, comprising an extrusion device, a preheating device and a straightening device, wherein the polyimide electromagnetic flat wire comprises a conductor and a polyimide insulating layer coated on the surface of the conductor; the extrusion device comprises a screw barrel, a hopper and a die; Features: The screw barrel is provided with a first exhaust hole, which is used to exhaust the gas generated in the extrusion process. There are a plurality of first exhaust holes, which are evenly distributed on the screw barrel. The first exhaust holes are connected to a negative pressure device or a vacuum device; The hopper is arranged at one end of the screw barrel, and the hopper includes a material holding section and a connecting section, the material holding section is used to hold polyimide particles, and the connecting section is used to connect the material holding section and the screw barrel; the connecting section is provided with an anti-clogging metering device, and the anti-clogging metering device includes a feeding gear and a reduction motor, the feeding gear is driven by the reduction motor, and the reduction motor and the feeding gear can control the polyimide particles to enter the screw barrel at a preset rate.
2. The polyimide flat electromagnetic wire preparation device according to claim 1, Features: The connecting section is provided with a second exhaust hole, and the second exhaust hole is used to exhaust excess air during the feeding process; there are a plurality of second exhaust holes, which are evenly distributed on the connecting section, and the second exhaust holes are connected to a negative pressure device or a vacuum device.
3. The polyimide flat electromagnetic wire preparation device according to claim 1, Features: The die is arranged at one end of the screw barrel away from the hopper, and the die includes a wire inlet and a wire outlet; the preheating device is connected to one end of the straightening device, and the other end of the straightening device is connected to the wire inlet of the die. After being preheated by the preheating device, the wire enters the straightening device for straightening, and the straightened wire enters the die from the wire inlet of the die.
4. The polyimide flat electromagnetic wire preparation device according to claim 1, Features: The preheating device includes a heating element, which is used to heat the wire in the preheating device to a preset temperature, and the preset temperature is 370°C-440°C; the preheating device is provided with a protective gas inlet for introducing a protective gas, and the protective gas is used to prevent the wire from being oxidized during the preheating process.
5. The polyimide flat electromagnetic wire preparation device according to claim 4, Features: The screw barrel is provided with a heating unit, which is evenly arranged along the axial direction and the circumferential direction of the screw barrel. The heating unit is used to heat the polyimide particles in the screw barrel into a molten fluid state, and the heating temperature is 370°C-440°C.
6. The polyimide flat electromagnetic wire preparation device according to claim 3, Features: The distance between one end of the straightening device connected to the preheating device and one end connected to the wire inlet of the handpiece is no more than 15 mm. 7 . The polyimide electromagnetic flat wire preparation device according to claim 6 , wherein a heat preservation structure is provided on the periphery of the straightening device, and the heat preservation structure is used to reduce the heat loss of the wire when passing through the straightening device.
8. A method for preparing a polyimide flat electromagnetic wire using the polyimide flat electromagnetic wire preparation device according to any one of claims 1 to 7, It is characterized in that The following steps are involved: S1: Preheating the wire: introducing the prepared wire into the preheating device for preheating, the preheating temperature is 370°C-440°C; S2: Wire straightening: introducing the preheated wire into the straightening device for straightening, and introducing the straightened wire into the handpiece through the wire inlet of the handpiece; S3: extrusion of polyimide insulation layer: the polyimide particles enter the screw barrel through the hopper for melt extrusion and enter the die. Inside the die, the extruded polyimide material coats the wire to form a polyimide insulation layer on the outer surface of the wire. The wire coated with the polyimide insulation layer is led out through the wire outlet of the die. The melting temperature of the polyimide particles is adapted to the preheating temperature of the wire in step S1, which is set to 370°C-440°C. S4: Cooling and coiling: A cooling system cools the wire coated with the polyimide insulation layer that is led out through the wire outlet of the machine head, and coils it through a coiling device to form a final electromagnetic flat wire product.
9. The method for preparing the polyimide flat electromagnetic wire according to claim 8, Features: In step S3, during the entire feeding and extrusion process, the first exhaust hole and the second exhaust hole are respectively connected through an external negative pressure device or a vacuum device to timely exhaust the gas in the feeding and extrusion processes.
10. The method for preparing the polyimide flat electromagnetic wire according to claim 8, Features: In step S1, before the wire is preheated, the wire is unwound through an unwinding device, and sequentially passes through the preheating device, the straightening device, the machine head and the cooling system to be connected to the winding device, and the pre-tensioning of the wire before the preparation of the polyimide electromagnetic flat wire is achieved through a tension control system.