A toroidal coil arrangement and method of manufacture thereof

Abstract

This invention belongs to the field of airborne sensor technology and discloses a ring coil device and its manufacturing method. The ring coil device includes a ring-shaped iron core, at least two sets of enameled wires wound on it, an insulating curing layer, an encapsulation shell, and an elastic potting compound. The end of each set of enameled wires is formed by twisting the enameled wire with multiple auxiliary wires to form a reinforced lead segment, which is then segmentally impregnated and cured with insulating varnish before being encapsulated in the shell by the elastic potting compound. The manufacturing method includes steps such as winding, reinforcing and twisting the lead segments, segmentally impregnating with insulating varnish, and potting molding. This invention solves the processing problems of easy breakage and difficult splicing of ultra-fine enameled wires through a twisted and thickened structure; by combining segmented impregnation with elastic potting, it provides the coil with excellent insulation, buffering, and temperature resistance, enabling it to operate stably for a long time in high-temperature and high-vibration environments. This makes the ring coil device structurally reliable and suitable for airborne speed sensors in aero engines that require high-reliability multi-channel signal output.

Description

Technical Field

[0001] This invention belongs to the field of airborne sensor technology, and specifically relates to a ring coil device and its manufacturing method. Background Technology

[0002] Accurate measurement of aircraft engine speed is crucial for the stable operation of its control system and is typically accomplished by an airborne speed sensor. To achieve high reliability and safety margin, the airborne speed sensor uses an isolated multi-output structure to measure engine speed. This structure features a primary coil at the front end of the sensor and a secondary loop coil at the rear end to perform a secondary conversion on the speed signal before outputting the signal.

[0003] However, due to the limited installation space on the engine, the size of the sensing element at the front end of the sensor is usually extremely compressed, resulting in a very weak raw electrical signal generated by the primary coil. To meet the sensor's high requirements for output signal amplitude, as many turns as possible must be wound within the limited space of the rear-end ring coil, which usually means using extremely fine enameled wire (approximately 0.1 mm). But this presents a significant technical challenge: Low processing reliability: The thin enameled wire is prone to bending and breakage during winding, lead-out, and welding processes. Furthermore, due to its fragile physical form, it is not easy to perform secondary transfers, which seriously threatens the manufacturing yield and long-term reliability of the sensor.

[0004] High environmental adaptability requirements: Airborne speed sensors operate in extreme environments with high temperature and strong vibration for extended periods. This not only requires the internal coil itself to have excellent vibration resistance and high temperature tolerance, but also imposes stringent requirements on insulation, heat dissipation, and structural integrity.

[0005] Currently, conventional coil processing and packaging technologies, such as current transformer solutions used in the instrumentation field, are insufficient to meet the aforementioned specific requirements. For example: Chinese patent application number 202210953099.1 discloses a secondary lead structure and packaging process for a miniature current transformer. It uses a copper sleeve to fix the enameled wire and laser / ultrasonic welding for connection. However, it has insufficient ability to withstand vibration stress and is prone to solder joint fatigue or lead wire breakage under continuous vibration.

[0006] Chinese patent application number 201611007743.7 discloses a current sensor, its coil packaging method and electronic current transformer. It uses foam filler for packaging. Although the process is simple and the weight is light, the foam material will expand severely or even fail in long-term high temperature environment exceeding 150°C, resulting in a sharp decline in coil reliability.

[0007] Chinese patent application number 201210544754.4 discloses a current transformer and its packaging manufacturing method. It relies on the structural cooperation between the coil and the heat shrink tubing, which requires high assembly accuracy. It also relies on the tightening force of the heat shrink tubing for fixation, which also has the problems of unreliable fixation and poor vibration resistance under strong vibration environment.

[0008] In summary, existing technologies generally suffer from limitations in achieving a balance between high-temperature resistance, strong vibration resistance, and good processing adaptability (especially for ultra-fine enameled wires), making them unsuitable for direct application in airborne speed sensors for aero-engines, where reliability and environmental adaptability are extremely critical. Therefore, there is an urgent need for a novel ring coil device and its manufacturing method to fundamentally solve the long-term reliability problems of ultra-fine enameled wires in processing, transfer, and harsh environments, while ensuring high sensor sensitivity and multi-output functionality. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a toroidal coil device and its manufacturing method.

[0010] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a toroidal coil device, comprising: toroidal iron core; At least two sets of enameled wire are wound on the toroidal iron core. A reinforced lead segment is provided at the end of each group of enameled wires and is formed by twisting together the head end and tail end of the enameled wires and multiple auxiliary wires. An insulating and curing layer is wrapped around the outer surface of the toroidal iron core on which the enameled wire is wound and in the gaps of the enameled wire to form a coil semi-finished product. A packaging shell having a receiving cavity; An elastic potting compound is filled into the receiving cavity, and the coil semi-finished product is encapsulated in the packaging shell.

[0011] Preferably, the at least two sets of enameled wires constitute electrically insulated independent windings.

[0012] Preferably, the auxiliary line and the enameled wire are made of the same material.

[0013] Preferably, the insulating curing layer is formed by repeatedly impregnating and curing insulating varnish.

[0014] Preferably, the encapsulation shell is made of a high-temperature resistant polymer material.

[0015] Preferably, the elastic potting compound is silicone.

[0016] Preferably, the portion of the reinforced lead segment extending beyond the elastic potting compound and the encapsulation shell is fitted with a protective sleeve.

[0017] The present invention also provides a method for manufacturing a toroidal coil device, for manufacturing the toroidal coil device as described above, the method comprising the following steps: Winding: The enameled wire is wound into at least two sections on the toroidal iron core to form electrically insulated independent windings; Reinforcement: At the beginning and end of the enameled wire of each winding, multiple auxiliary wires are twisted together to form a reinforced lead segment; Impregnation: The toroidal iron core wound with the enameled wire is impregnated with insulating varnish multiple times and cured to form an insulating and cured layer, thus obtaining a coil semi-finished product; Encapsulation molding: The coil semi-finished product is placed in the encapsulation shell, and elastic potting compound is injected into the receiving cavity, so that the elastic potting compound is cured to form an elastic potting compound encapsulating the coil semi-finished product.

[0018] Preferably, in the impregnation step, the process of repeatedly impregnating and curing the insulating varnish includes at least one medium-temperature curing stage and at least one high-temperature curing stage.

[0019] Preferably, in the potting molding step, before or after pouring the elastic potting compound, a protective sleeve is fitted onto the reinforced lead segment so that one end of the protective sleeve extends into the elastic potting compound.

[0020] Compared with the prior art, the present invention has the following advantages: 1. This invention involves thickening the head and tail ends of extremely fine enameled wire (approximately 0.1 mm) by twisting multiple strands of the same material auxiliary wire together, forming a reinforced lead segment without welding. This effectively solves the problem of bending and breakage that easily occurs during the winding and lead-out process of enameled wire. The reinforced lead segment has a doubled cross-sectional area and significantly improved mechanical strength, which not only enhances its own resistance to bending and tensile stress and disperses environmental vibration stress, but also makes it easier and more reliable to weld or crimp to external terminals. This fundamentally overcomes the core processing problem of "easy breakage and difficult splicing" of ultra-fine enameled wire, ensuring a high yield rate.

[0021] 2. This invention uses a toroidal iron core in conjunction with multiple independently wound enameled wire windings to form an isolated multi-output structure. This structure can not only efficiently convert weak primary induction signals into secondary signals and enhance the output, but also achieve signal shunting. Even if a single winding fails, the other windings can still work normally, thereby greatly improving the measurement reliability and system safety margin of the entire airborne speed sensor.

[0022] 3. This invention employs a synergistic protection strategy of segmented impregnation insulation and elastic potting compound. First, the segmented impregnation insulation varnish fully fills all gaps between the enameled wires, eliminating air and solidifying the loose coil into a whole, greatly improving internal insulation strength, mechanical rigidity, and heat dissipation efficiency. Second, highly elastic, high-temperature resistant silicone is used for potting within a high-temperature resistant shell, providing the coil with a protective layer that combines excellent buffering, high dielectric strength, good thermal conductivity, and wide temperature stability. The synergy of these two methods provides a double barrier for the internal coil, significantly improving the coil's environmental stability, operational reliability, and service life.

[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A top view schematic diagram of the toroidal coil device of the present invention is shown; Figure 2 A cross-sectional schematic diagram of the annular coil device of the present invention is shown; Figure 3 A flowchart illustrating the manufacturing method of the toroidal coil device of the present invention is shown.

[0026] In the diagram: 1. Enamelled wire; 2. Toroidal core; 3. Insulation curing layer; 4. Auxiliary wire; 5. Protective sleeve; 6. Elastic potting compound; 7. Encapsulation shell. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0029] This invention provides an innovative toroidal coil device.

[0030] like Figure 1 As shown, the toroidal coil device includes: a toroidal core 2, at least two sets of enameled wires 1 wound on the toroidal core 2, an insulating curing layer 3, a reinforcing lead segment, an encapsulation shell 7, and an elastic potting compound 6 filled in the encapsulation shell 7. In this embodiment, the toroidal core 2 is made of a soft magnetic alloy with high permeability. The soft magnetic alloy has the advantages of high permeability, low coercivity and high saturation magnetic induction intensity. Its function is to efficiently conduct magnetic flux, enhance the electromagnetic induction effect of the coil, and significantly improve the output performance of the sensor. Furthermore, at least two sets of enameled wires 1 constitute electrically insulated independent windings, and reinforced lead segments are provided at the ends of each set of enameled wires 1, which are formed by twisting together the head end and tail end of the enameled wires 1 and multiple auxiliary wires 4. In this embodiment, the enameled wire 1 is divided into two or three groups (three groups are shown in the figure), and is wound evenly and independently on the iron core. This can convert a single speed signal source into multiple independent outputs, realize the split output of the speed signal, and significantly improve the safety margin and reliability of signal transmission. At the beginning and end of each enameled wire 1 winding, 3-5 strands of auxiliary wire 4 of the same material are wound and twisted together with the enameled wire 1 body to form a thickened and reinforced lead section. The auxiliary wire 4 and the enameled wire 1 are made of the same material. The process is simple, easy to implement, and has good compatibility. It can locally thicken the extremely thin enameled wire, which greatly enhances the coil lead's resistance to bending, tension, and fatigue under processing and vibration environments. In this embodiment, the stranding length of the reinforced lead segment is 20-50mm, and it is wound about 10 times. After the stranding, the cross-sectional area of ​​the lead end is doubled, realizing the "thickening from thin" of the lead in the non-welding method. This solves the problem that enameled wire is not easy to transfer, and makes it easier to weld and fix the lead to the signal output terminal.

[0031] Furthermore, the insulating curing layer 3 covers the outer surface of the toroidal iron core 2 on which the enameled wire 1 is wound and the gaps in the enameled wire 1, forming a coil semi-finished product; In this embodiment, the insulating curing layer 3 is formed by repeatedly impregnating and curing the insulating varnish. This can fully eliminate air inside the coil, allowing the insulating varnish to fill the gaps in the enameled wire 1 as much as possible, bonding the loose enameled wire 1 into a solid whole. This prevents the problem of short circuits caused by friction and wear of the enameled wire 1, significantly improving the breakdown voltage and insulation of the coil. Furthermore, the thermal conductivity of the insulating varnish is better than that of air, which more effectively conducts and dissipates ambient heat from the enameled wire inside the coil, improving heat dissipation efficiency.

[0032] like Figure 2As shown, the encapsulation shell 7 has a receiving cavity, the elastic potting compound 6 is filled into the receiving cavity, and the coil semi-finished product is encapsulated in the encapsulation shell 7; In this embodiment, the encapsulation shell 7 is made of a high-temperature resistant polymer material, such as PEEK (Polyether EtherKetone), a high-temperature resistant and high-strength engineering plastic. This provides sufficient mechanical strength and dimensional stability for the internal coil, protecting it from external mechanical stress. The elastic potting compound 6 is made of silicone, filling the entire space between the cured coil and the shell. After curing, it forms an elastic protective layer with extremely high dielectric strength (greater than 20KV / mm). Even in humid and hot environments, it ensures that the internal coil will not discharge to the shell or experience inter-turn short circuits. At the same time, it has a large thermal conductivity (greater than 0.6W / m˙K) and moderate Shore hardness (30-60HSA), which can absorb vibration and impact energy from the external environment, protect the internal coil structure, and dissipate the heat generated by the coil, extending its service life.

[0033] Furthermore, a protective sleeve 5 is fitted over the portion of the reinforcing lead segment that extends beyond the elastic potting compound 6 and the encapsulation shell 7; In this embodiment, the exposed leads outside the elastic potting compound 6 are inserted into the Teflon protective sleeve 5 to further improve the tensile and bending resistance of the exposed reinforced lead segments and to provide them with physical isolation and protection.

[0034] The present invention also provides a method for manufacturing a toroidal coil device, for manufacturing the toroidal coil device as described above.

[0035] like Figure 3 As shown, the method includes the following steps: S1 winding: Enamelled wire 1 is wound in at least two sections on toroidal iron core 2 to form independent windings with electrical insulation; In the winding process, each group of enameled wire 1 windings has the same number of turns, forming multiple mutually insulated secondary induction coils on the toroidal iron core 2. When an external alternating magnetic field (generated by the primary coil of the sensor) passes through the iron core, each winding will induce an independent electrical signal due to mutual inductance.

[0036] S2 reinforcement: At the beginning and end of the enameled wire 1 of each winding, multiple auxiliary wires 4 are twisted together to form a reinforced lead segment; In the reinforcement step, at the beginning and end of each winding, 3-5 strands of auxiliary wire 4 of the same material are twisted together with the body of the enameled wire 1 to form a thickened reinforcement lead segment. The twisting length is preferably 20-50mm. Through multi-strand twisting, the original single thin enameled wire is transformed into a strong composite wire with a doubled cross-sectional area, which enhances the tensile, bending and vibration fatigue resistance of the coil lead.

[0037] S3 Impregnation: The toroidal iron core 2 wound with enameled wire 1 is impregnated with insulating varnish and cured multiple times to form an insulating curing layer 3, thus obtaining a coil semi-finished product. In the impregnation process, the multiple impregnation and curing of insulating varnish includes at least one medium-temperature curing stage and at least one high-temperature curing stage. That is, a segmented impregnation process is adopted. First, a medium-temperature curing stage is carried out: impregnation for 30 minutes, curing at 100°C for 2 hours, and curing at 180°C for 3 hours; then a high-temperature curing stage is carried out: impregnation for 30 minutes, curing at 100°C for 2 hours, and curing at 200°C for 8 hours. This allows the insulating varnish to fully and thoroughly penetrate, fill and cure, forming a dense insulating cured layer on the coil surface. In this embodiment, the segmented, stepped heating curing process allows the insulating varnish to fully and thoroughly penetrate, fill, and cure; the medium-temperature stage allows the varnish to initially penetrate and pre-cur, expelling most of the air and solvent; the high-temperature stage performs deep curing, making the varnish molecules more fully cross-linked and forming a strong insulating layer.

[0038] S4 potting molding: The coil semi-finished product is placed in the encapsulation shell 7, and elastic potting glue is poured into the cavity to allow the elastic potting glue to cure and form an elastic potting glue 6 encapsulating the coil semi-finished product; In the potting molding step, the coil semi-finished product that has been impregnated and cured is placed into the PEEK high-temperature substrate shell 7, and then silicone is injected to fill all the gaps. At the same time, the exposed reinforced lead segment is covered with a Teflon protective sleeve 5, and one end of the sleeve is inserted into the silicone. Finally, the silicone is cured at room temperature for more than 24 hours to form an elastic potting colloid 6. In this embodiment, the PEEK shell, silicone rubber, and Teflon sleeve form the ultimate barrier against harsh environments (high temperature, strong vibration).

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A toroidal coil device, characterized in that, include: Annular iron core (2); At least two sets of enameled wire (1) are wound on the toroidal iron core (2). The reinforcing lead segment is set at the end of each group of enameled wires (1), and is formed by twisting together the head end and tail end of the enameled wires (1) and multiple auxiliary wires (4); An insulating curing layer (3) is applied to the outer surface of the toroidal core (2) on which the enameled wire (1) is wound and to the gaps in the enameled wire (1) through a segmented impregnation process to form a coil semi-finished product. The encapsulation housing (7) has a receiving cavity; An elastic potting compound (6) is filled into the cavity and the coil semi-finished product is encapsulated in the encapsulation shell (7).

2. The toroidal coil device according to claim 1, characterized in that, The at least two sets of enameled wires (1) constitute electrically insulated independent windings.

3. The toroidal coil device according to claim 1, characterized in that, The auxiliary line (4) and the enameled wire (1) are made of the same material.

4. The toroidal coil device according to claim 1, characterized in that, The insulating curing layer (3) is formed by repeatedly impregnating and curing the insulating varnish.

5. A toroidal coil device according to claim 1, characterized in that, The encapsulation shell (7) is made of high-temperature resistant polymer material.

6. A toroidal coil device according to claim 1, characterized in that, The elastic potting compound (6) is silicone.

7. A toroidal coil device according to claim 1, characterized in that, The portion of the reinforced lead segment extending beyond the elastic potting compound (6) and the encapsulation shell (7) is fitted with a protective sleeve (5).

8. A method for manufacturing a toroidal coil device, used to manufacture the toroidal coil device as described in any one of claims 1-7, characterized in that, The method includes the following steps: Winding: The enameled wire (1) is wound into at least two sections on the toroidal iron core (2) to form electrically insulated independent windings; Reinforcement: At the head and tail ends of the enameled wire (1) of each winding, multiple auxiliary wires (4) are twisted together to form a reinforced lead segment; Impregnation: The toroidal iron core (2) wound with the enameled wire (1) is impregnated with insulating varnish and cured multiple times to form an insulating curing layer (3) and obtain a coil semi-finished product; Encapsulation molding: The coil semi-finished product is placed in the encapsulation shell (7), and elastic potting compound is injected into the cavity to cure the elastic potting compound to form an elastic potting compound (6) encapsulating the coil semi-finished product.

9. A method for manufacturing a toroidal coil device according to claim 8, characterized in that, In the impregnation step, the process of repeatedly impregnating and curing the insulating varnish includes at least one medium-temperature curing stage and at least one high-temperature curing stage.

10. A method for manufacturing a toroidal coil device according to claim 8, characterized in that, In the potting molding step, before or after the injection of the elastic potting compound, a protective sleeve (5) is fitted onto the reinforced lead segment so that one end of the protective sleeve (5) extends into the elastic potting compound (6).

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