274results about "Encapsulation/impregnation" patented technology

The invention discloses a vacuum pressure impregnation mold assembly process and a mold. The process comprises the following steps: mounting bottom hard molds on a plurality of independent supporting platforms, and then positioning superconducting coils; descending the platform in sections to lay a bottom soft mold and a flow guide component to ensure uniform gaps; the side edge soft mold, the side edge hard mold, the top flow guide net and the soft and hard mold are sequentially installed, and finally the soft mold is subjected to segmented welding and the hard mold is reinstalled. The mold is assembled through the method, and modular assembly is achieved by lifting the independent supporting platform in stages. According to the process, the load of a single platform is reduced through sectional assembly, precision deviation and equipment damage are avoided, and meanwhile, the use of a lifting appliance is reduced to protect the dimensional stability of the coil; a soft and hard mold layered assembly mode is adopted, the machining difficulty of a large-size mold is simplified, the manufacturing cost is reduced, and the size control precision is improved; the step-by-step assembly process effectively reduces the wrong assembly risk, avoids the problem of glue injection port blockage, and ensures the success rate of the vacuum pressure impregnation process.

The invention discloses an inductance device and a preparation method thereof.The method comprises the steps that aluminum oxide and epoxy resin are mixed according to a preset proportion, and an injection molding raw material is obtained; the injection molding raw materials are added into a charging barrel of injection molding equipment, and the target magnetic core is placed into a cavity of an injection mold; the injection mold is moved to injection molding equipment for mold locking; injection molding equipment is controlled to pour injection molding raw materials into an injection molding cavity, and the injection molding raw materials enter a cavity of the injection mold through a nozzle; when a cavity of the injection mold is filled with the injection molding raw material, the injection molding raw material is subjected to pressure maintaining for first preset time; cooling for a second preset time through a cooling system arranged in the injection mold; and demolding to obtain the inductive device with the plastic shell formed on the surface of the target magnetic core. The problems that the consistency and the yield of the inductor device cannot be well guaranteed in an existing magnetic core shell mounting mode, the production cost of the inductor device is high due to manual participation of magnetic core shell mounting, and the market competitiveness is insufficient are solved.

A coil component includes an exterior body, a coil, and a pair of terminal electrodes. The coil is disposed inside the exterior body. The pair of terminal electrodes are electrically connected to the coil and are disposed on the exterior body. The exterior body includes a first portion that covers the coil and is made of a resin, and a second portion including a side surface on which the pair of terminal electrodes are disposed. The second portion includes a material having a relative permittivity lower than a relative permittivity of the resin and is disposed between the coil and the pair of terminal electrodes.

A molded inductor includes a winding having leads configured for attaching leads of the winding to pads on a package substrate, having a magnetic core with a body disposed within the winding, wherein the magnetic core has at least one mold flow enhancing feature that enhances a filling of a magnetic mold material as compared to a filling provided by a uniform cylindrical body. The magnetic mold material encases the winding and the magnetic core to form either a standalone discrete inductor component, or the magnetic component of an output filter of an integrated switching power converter module.

A casting type power inductor includes a base, a hollow coil, and a casting. The base includes a flange and a central column. The central column is fixedly arranged at the center of the flange. The hollow coil is tightly wound on the central column. The casting is used for wrapping the base and the hollow coil. The preparation method for the casting type power inductor includes blank preparation, coil winding, combined body arrangement, slurry casting, curing treatment, and post-treatment that are sequentially performed. According to the casting type power inductor, pressureless forming can be implemented by casting a magnetic slurry, so that a short circuit, an open circuit, or deviation to the edge of the inductor, of the coil caused by excessive pressure is avoided.

The application relates to the technical field of inductor production equipment, and discloses a common-mode inductor glue dispensing and assembling machine, which comprises a machine base, an inductor material bin device, an inductor material taking and feeding device, an inductor glue dispensing device and a common-mode magnetic sleeve loading and pressing device. The inductor material bin device comprises a material bin box and a material disc, and the inductor material taking and feeding device transfers the material disc to the inductor glue dispensing device. The inductor glue dispensing device comprises a second movable seat and a third movable seat, the second movable seat is provided with a second conveying mechanism, the third movable seat is provided with a glue dispensing mechanism, a first industrial camera mechanism and a grabbing mechanism. The common-mode magnetic sleeve loading and pressing device comprises a common-mode magnetic sleeve loading vibrating disc mechanism, a fourth movable seat and a fifth movable seat, the fourth movable seat is provided with a third conveying mechanism, and the fifth movable seat is provided with a pressing mechanism. The common-mode inductor glue dispensing and assembling machine has the advantages of high integration, high automation and strong continuous working capacity, and can effectively improve the production efficiency and product quality.

A method for manufacturing a reactor includes a bonding process of joining molded cores with a molded coil with an adhesive, and a welding process of connecting, by welding, the lead wire of a coil to a busbar fixed to the molded core. The coils are attached to respective leg portions. The bonding process includes an applying process of applying the adhesive to the joining surfaces of the respective leg portions of each of the core members, and the inner circumferential surfaces of the respective yoke portions of the core members, a depressing process of spreading the applied adhesive by depression, and a curing process of curing the adhesive.

The application discloses a manufacturing method of an involute transformer core, which comprises the following steps: S1, cutting a stainless steel silicon steel sheet to obtain a silicon steel sheet blank; S2, using a rolling tool to manufacture the silicon steel sheet blank into an involute silicon steel sheet; S3, stacking a plurality of the involute silicon steel sheets on the periphery of a base cylinder, and tightly holding the involute silicon steel sheets and the base cylinder by using a plurality of stainless steel hoops to form a holding piece, and annealing the holding piece as a whole; S4, bundling; S5, preheating the bundled piece; S6, immersing the preheated bundled piece into insulating paint; S7, solidifying the bundled piece; S8, surface treatment; and S9, gluing, coating epoxy glue on the outer surface of the component which has been surface treated in the step S8, and firmly bonding the component with an epoxy cylinder. The manufacturing method of the involute transformer core provided by the application has single specification of the involute silicon steel sheet, avoids a plurality of specifications of the width of the radial silicon steel sheet, is convenient to manage, and reduces storage devices.

The present invention provides a power module and a manufacturing method thereof. The power module includes a substrate, an electronic component, a magnetic component, and a plastic encapsulation component. The substrate includes a first surface, a second surface, and an operating area, wherein the first surface and the second surface are opposite to each other, and the operating area is disposed on the first surface or the second surface; the electronic component is disposed on the substrate; the magnetic component is disposed in the operating area of ​​the substrate and has a side periphery; and the plastic encapsulation component is disposed on the substrate, covering the electronic component and at least partially surrounding the side periphery of the magnetic component, wherein the projections of the plastic encapsulation component and the operating area on the first surface of the substrate do not overlap, and a gap is formed between the plastic encapsulation component and the side periphery of the magnetic component.

The application discloses an inductor, which comprises a packaging shell, an input pole, an output pole and a metal shielding layer. The inductor is characterized in that the inductor is internally packaged with an inductive component; the input pole is exposed on the surface of the packaging shell and used for receiving an alternating voltage; the output pole is exposed on the surface of the packaging shell and used for outputting a direct current voltage; the metal shielding layer is asymmetrically covered on the surface of the packaging shell and electrically connected with the output pole; and the metal shielding layer still keeps the input pole and the output pole electrically isolated. The application further provides an inductor manufacturing method and a power supply circuit comprising the inductor, solves the problems of small electromagnetic shielding range, poor effect and unstable inductor potential in the prior art, and realizes better electromagnetic shielding effect and stable inductor potential.

The application discloses a paraffin solid sealing furnace for a vehicle-mounted superconducting magnet coil, wherein the melting paraffin cabin and the solid sealing cabin are combined into one, and the structure is compact; the paraffin groove is arranged in the solid sealing furnace, the original paraffin pipeline exposed to the environment can be cancelled, the temperature reduction, solidification, blockage and injection of paraffin in the pipeline due to flow can be avoided, the pouring process is smooth and controllable, and a good solid sealing effect is achieved. In terms of temperature control, mainly using air convection to conduct heat transfer, scientifically arranging the electric heating pipe and the turbulence fan, effectively eliminating the temperature gradient inside the coil and the paraffin, and improving the uniformity of the temperature distribution. In terms of pouring control, the vibration exciter arranged below the superconducting coil tray can effectively accelerate the discharge of bubbles inside the coil. In terms of vacuum control, only slight negative pressure in the furnace needs to be maintained, which greatly reduces the performance of the vacuum pump, the sealing requirement of the furnace body, the manufacturing difficulty and the cost.

The invention discloses a magnetic track brake electromagnet coil, a magnetic track brake electromagnet and a preparation method. The magnetic track brake electromagnet coil comprises a winding, a coil frame, an insulating layer, a cover plate and a heat insulation layer. The winding is arranged in a coil groove of the coil rack, and the winding is formed by winding an enameled flat copper wire of which the temperature resistance level is H level or higher; the insulating layer wraps the winding; the cover plate is welded and fixed at the opening of the coil slot and is used for sealing the coil slot; the heat insulation layer is arranged at the position, corresponding to the welding position of the cover plate, in the coil groove and used for blocking heat generated when the cover plate is welded. Damage of welding heat to the coil is effectively avoided, the overall sealing performance and environmental adaptability of the coil are improved, and therefore long-term stable operation of the coil is guaranteed.

A preparation method and composite core for a current transformer, comprising the following steps: separately preparing a silicon steel core, an SMC molded lining, and an amorphous core; embedding the silicon steel core into the SMC molded lining to form a shell; placing the amorphous core into the shell; placing epoxy resin and a curing agent in a blender and stirring and mixing them to obtain a mixture I; pouring the obtained mixture I into the shell, allowing the mixture I to completely penetrate the amorphous core, covering the amorphous core, and then curing; after curing, placing the epoxy resin, curing agent, and silicon powder in a blender and stirring and mixing them to obtain a mixture II; pouring the mixture II into the shell, filling the shell, and curing it to obtain the composite core. The composite core obtained by the above steps of the present invention has improved mechanical properties, protects the silicon steel core and the amorphous core from stress, effectively reduces the composite core buffer layer, increases the effective distance of the main insulation, and improves the power frequency withstand voltage, partial discharge level, measurement accuracy, and protection multiple of the current transformer.

Manufacturing system (1) for the manufacture of a stator (2) and / or a rotor (3) of an electric machine (4), comprising: wherein a holding tool (5) for receiving a plurality of stacked annular disc-shaped electrical steel sheets (6), wherein the holding tool (6) has a clamping mandrel (7) for fixing the electrical steel sheets (6) to the inner diameter (8) of the clamping mandrel (7), and a base plate (10) at a first axial end (9) of the clamping mandrel (7) and a cover plate (12) at a second axial end (11), wherein an axial stress can be introduced into the electrical steel sheets (6) arranged on the clamping mandrel (7) via the base plate (10) and / or the cover plate (11); a baking lacquer tool (20) into which the holding tool (5) equipped with the electrical steel sheets (6) can be inserted and adjusted to a baking lacquer temperature; a transfer molding tool (30) into which the holding tool (5) equipped with the electrical steel sheets (6) can be inserted and adjusted to a molding temperature, characterized in that the holding tool (5) comprises a injection geometry which, in a state inserted into the transfer molding tool (30), influences the shaping and / or the flow of the plastic during the transfer molding process.

The invention discloses a fully automatic winding machine capable of reserving a margin of lead wire, comprising a winding device, a shell insertion device, a margin limiting device, a wire dividing device and a foot wrapping device; the winding device comprises a wire upper assembly, an upper ring assembly and a winding assembly; the winding assembly is used to wind the winding wire on a magnetic ring to form a first workpiece; the shell insertion device is connected to the rear end of the winding device, and is used to load the first workpiece into the shell to form a second workpiece; the margin limiting device is connected to the rear end of the shell insertion device, and is used to limit the lead wire margin of the winding wire on the second workpiece; the wire dividing device is connected to the rear end of the margin limiting device; the foot wrapping device is connected to the rear end of the wire dividing device; through the above structure, the fully automatic production of wire winding, shell insertion, lead wire margin limiting, wire dividing and foot wrapping of the magnetic ring can be realized, which not only greatly improves the production efficiency, but also ensures that in the produced products, there is enough margin between the pins of the magnetic ring and the shell to avoid the situation of lead wire breakage.

A method of fabricating a high-temperature bobbin for a solenoid or other electrical assembly includes the step of providing a bobbin configured for use in the assembly. The bobbin is coated with an anti-oxidation composition and an anti-corrosion composition to produce an oxidation / corrosion resistant bobbin. The oxidation / corrosion resistant bobbin is coated with an electrical insulating composition that is resistant to corona discharge at or below a predetermined voltage threshold to produce an insulated and oxidation / corrosion resistant bobbin. The anti-oxidation composition, the anti-corrosion composition, and the electrical insulating composition can withstand temperatures of subzero up to temperature greater than 1000° F.

Impregnation device (2) for impregnating bodies (4), in particular wound materials, with at least one holding device (6) having at least one holding means (8) on which a body (4), in particular a wound material, can be fixed, with at least one first working area (10) in which at least the body (4) can be fixed on the holding means (8) and in which the body (4) can be released from the holding means (8) again, with at least one second working area (12) in which at least one impregnation container (14) is arranged which is filled with a fluid impregnating the body (4), with at least one transfer device (16) by which the holding means (8) can be transferred from the first working area (10) to the second working area (12) and back, and with at least one electric heating unit (18) comprising at least one contact means (20) fixed in or on the holding means (8),the body (4) can be manually or automatically connected or connected in the arrangement of the body (4) fixed on the holding means (8) with at least one phase connection (22) of the body (4), which can be continuously and without interruption connected or connected to a power supply of the electric heating unit (18) when the holding means (8) is transferred from the first working area (10) to the second working area (12), and by which the body (4) can be electrically heated continuously and without interruption in the first working area (10) and in the second working area (12), wherein the transfer device (16) comprises at least one bearing unit (30) comprising a rotary axis (28), wherein the transfer of the at least one holding means (8) from the first working area (10) to the second working area (12) comprises a rotary or oscillating movement about the rotary axis (28) of the bearing unit (30), characterized by at least one lifting / lowering device (34),comprising at least one first lifting / lowering means (36) in the first working area (10) by which the body (4) is movable, in particular liftable, along a first direction of movement (38) onto the holding means (8), and comprising at least one second lifting / lowering means (40) in the second working area (12) by which the impregnation container (14) is movable, in particular liftable, along a second direction of movement (42) onto the body (4), and the body (4) is arrangable in the fluid, wherein the first direction of movement (38) and the second direction of movement (42) are parallel to the axis of rotation (28) of the bearing unit (30).

The invention relates to a high-frequency thin film magnetic bead and a preparation method and application thereof. The preparation method comprises the steps that a Fe source, a Si source, a B source, a Cu source, a Nb source and a Ga source are smelted into a first alloy ingot according to a formula, then the first alloy ingot and a C source are smelted to prepare a second alloy ingot, the second alloy ingot is prepared into an amorphous alloy strip, and an iron-based nanocrystalline alloy is obtained through magnetic field heat treatment; the method comprises the following steps: mixing an iron-based nanocrystalline alloy and aluminum oxide to form a magnetic mixture, placing the magnetic mixture in a mold provided with a surrounding wire, carrying out pressure forming to obtain a thin-film-shaped magnetic blank, and sintering the thin-film-shaped magnetic blank in an inert gas environment to obtain a magnetic bead blank; and mixing an insulating material with graphite, forming a coating layer on the surface of the magnetic bead blank to obtain a magnetic bead body, and arranging an electrode electrically connected with the surrounding wire on the magnetic bead body to obtain the high-frequency thin-film magnetic bead. According to the invention, the material and the structure of the magnetic bead are optimally designed, so that the high-frequency thin-film magnetic bead with better magnetic performance and smaller volume can be obtained.

The invention belongs to the technical field of transformer processing, and particularly relates to a network transformer varnish dispensing device which comprises a rack, an incoming material belt line is sequentially installed on the rack, a product moving track is installed on one side of the incoming material belt line, and a varnish dispensing mechanism is installed on one side of the product moving track. One side of the varnish dispensing mechanism is provided with a varnish glue amount detection assembly, one side of the varnish glue amount detection assembly is provided with a defective product receiving mechanism, one side of the defective product receiving mechanism is provided with a defective product taking module, and one side of the defective product taking module is provided with a good product tray discharging and moving mechanism. And a full tray moving mechanism and an empty tray receiving lifting mechanism are further mounted on the rack. Automatic continuous feeding is achieved by integrating the incoming material belt line, the product moving track and the like, automatic material carrying is completed in cooperation with the full material disc moving mechanism and the like, and the production efficiency and continuity are improved; and precise operation of the varnish dispensing mechanism is combined with speed regulation control, so that the glue amount of varnish is uniform, and the product consistency is improved.

The application belongs to the technical field of soft magnetic material preparation, and particularly relates to a ferrosilicon magnetic material and a preparation method and application thereof. The preparation method comprises the following steps: (1) mixing ferrosilicon magnetic powder and a passivation agent, and then performing primary heat treatment and cooling to room temperature at a speed of not higher than 30 DEG C / h; (2) mixing the magnetic powder obtained in the step (1) with the passivation agent to obtain passivated magnetic powder; (3) adding a first coating agent to the passivated magnetic powder to perform primary coating, and then performing secondary heat treatment; and (4) adding a second coating agent to the magnetic powder obtained in the step (3) to perform secondary coating, pressing, and then performing tertiary heat treatment. The average particle size of the first coating agent is 300 nm-1 mu m; and the second coating agent comprises colloidal particles, and the average particle size of the colloidal particles is not higher than 100 nm. The preparation method can improve the density and effective magnetic permeability of the ferrosilicon magnetic material, so that the ferrosilicon magnetic material has excellent magnetic performance, the loss is greatly reduced, heat generation is reduced, and the device is beneficial to energy saving and high efficiency.

The invention relates to the technical field of magnetic functional materials, in particular to a high-pressure molded copper-iron co-fired inductor and a preparation method thereof. The preparation method comprises the following steps: S1, pretreating a copper sheet; s2, coating an insulating layer; s3, preparing soft magnetic metal powder; s4, preparing a magnetic powder core; and S5, preparing the copper-iron co-fired inductor: performing two-way compression molding on the magnetic powder core through a mold, performing gradient annealing on the magnetic powder core by using a reducing atmosphere, finally soaking the magnetic powder core in an epoxy resin acetone solution under the vacuum degree of 0.05 MPa, washing the magnetic powder core with acetone for three times, and baking the magnetic powder core to obtain the high-pressure molded copper-iron co-fired inductor. Through deep combination of material innovation (passivation / coating / lubrication system) and process optimization (stepped curing-bidirectional pressing-gradient annealing), breakthrough improvement of the high-pressure molded copper-iron co-fired inductor in the aspects of loss, voltage resistance, reliability and the like is realized, meanwhile, the production cost is remarkably reduced, and a core device is provided for upgrading of high-frequency power electronic equipment.

In one example, an integrated circuit (200) includes a substrate (206), a semiconductor die (104), metal interconnects (130, 132, 134, 136), an inductor (202) attached to the substrate, and a magnetic material (208) that encapsulates the semiconductor die, the inductor, and the metal interconnects. The semiconductor die is attached to the substrate via the metal interconnects. The magnetic material includes coated metal particles (510, 512, 514, 520, 522, 524, 526, 528, 530, and 532) that are coated with a first insulating material and a second insulating material (533) in which the coated metal particles are suspended.

The invention discloses a powder filling hot-pressing device for inductor processing, and belongs to the field of hot-pressing devices.The powder filling hot-pressing device comprises a workbench, a bottom die is arranged on the workbench, a plurality of forming cavities are formed in the top face of the bottom die, a mounting frame is arranged on the workbench, a top die is arranged above the bottom die, and a first air cylinder is arranged on the top face of the mounting frame; the bottom end of a piston rod of the first air cylinder is fixed to the bottom face of the top die, a plurality of hot-pressing heads are arranged on the bottom face of the top die and correspond to the multiple forming cavities, a movable base is arranged on one side of the top face of the workbench, two rows of powder conveying pipes are arranged on the bottom face of the movable base, a plurality of powder spraying nozzles are arranged on the powder conveying pipes and correspond to the multiple forming cavities, and the powder spraying nozzles correspond to the multiple forming cavities. The workbench is provided with a driving mechanism used for driving the movable base to move in the length direction of the workbench. The device has the effects that powder can be conveniently added into the forming cavity, and the phenomenon that arms of workers are scalded by a hot-pressing head is reduced.

The invention provides a power module. The power module comprises a substrate, a first electronic component, at least one metal component, a first metal connecting part and a second metal connecting part. The first electronic component and the at least one metal component are arranged on the first side of the substrate. The first metal connecting part and the second metal connecting part are arranged on the second side of the substrate. And the first metal connecting part is electrically connected with the first electronic component to form an input and / or output pin of the power module. And the second metal connecting part is at least electrically connected with the substrate to form a signal pin of the power module. The first side is opposite to the second side.

The invention relates to the technical field of transformer manufacturing, in particular to a laminated transformer preparation method and a laminated transformer. The preparation method of the laminated transformer comprises the following steps: respectively preparing ferrite powder and microcrystalline glass ceramic powder into a first green tape and a second green tape by adopting a tape casting process; forming through holes in the first green tape and the second green tape, and filling the through holes with conductive paste; a primary coil layer and a secondary coil layer are printed on the first hole filling green ceramic tape; laminating a plurality of coil hole-filling green ceramic tapes and a plurality of second hole-filling green ceramic tapes according to a preset sequence to form an intermediate electrode layer; laminating a plurality of first green tapes to form a cover layer; stacking the two cap layers and the intermediate electrode layer together to form a block; and sintering the laminated monomers to obtain the laminated transformer. The problems of interface stress concentration and structure cracking caused by difference of thermal expansion coefficients of different materials are effectively solved, and the product yield and reliability are remarkably improved.

The present invention discloses a packaging mold, a packaging mold assembly and a coil structure packaging system. Among them, the packaging mold includes: a mandrel, which is rod-shaped for extending into the central hole of the coil structure; a flange, which extends outward from the outer periphery of the mandrel, and at least one notch structure is provided on the flange, and the notch structure extends from the outer periphery of the flange towards the mandrel. The present invention solves the technical problem of poor exhaust performance during the packaging of the coil structure in the prior art.

A method for manufacturing a coil (1) comprising the steps of: a. providing a tube (2) with a tube wall (6) made of an electrically conductive material, b. creating a gap (4) in an inductive section (7) of the tube (2), wherein the gap (4) in the inductive section (7) forms the tube wall (6) into a helix, and forming at least two sections of the tube into contact sections (8), wherein in step b. a coil strand is first produced by creating several inductive sections (7) along the tube (2), in each of which a gap (4) is created which forms the tube wall (6) into a helix in the respective inductive section, and wherein a contact section (8) is formed between each of two inductive sections (7), which, after separation of the coil strand, forms an electrical connection to the two adjacent inductive sections (7).

The application discloses a winding inductance heat transfer pouring structure and method, which comprises a substrate, a heat conduction column is vertically arranged on the upper end surface of the substrate, a winding inductance is sleeved on the heat conduction column and located at the bottom of the substrate, a pouring cavity is arranged between the winding inductance and the heat conduction column, a pressing plate is detachably connected to the top of the winding inductance, a plurality of pouring openings are formed in the pressing plate and communicated with the pouring cavity, the winding inductance comprises an inductance magnetic ring, a first insulating film wrapped on the inductance magnetic ring, a second insulating film wrapped on the first insulating film and an inductance winding wound on the inductance magnetic ring, the inductance winding is located between the first insulating film and the second insulating film, and a plurality of pouring holes are formed in the first insulating film and the second insulating film and communicated with the pouring cavity. The application improves the heat dissipation efficiency and heat transfer capacity of the winding inductance and effectively solves the problem of heat accumulation of the winding inductance.

The present application discloses a coil module, a drive board, a camera device, and a preparation method. The coil module includes: two metal brackets and a coil; the coil is fixed to the two metal brackets, and the welding leads at both ends of the coil are respectively welded to the two metal brackets. The coil and the two metal brackets are plastic-encapsulated to form a plastic-encapsulated body, and the end faces of the two metal brackets are exposed on the surface of the plastic-encapsulated body. The coil module, drive board, camera device, and preparation method provided by the present application are used to solve the technical problem in the prior art that soldering the coil to the circuit board easily causes damage to the board and reduces the yield rate. The technical effect of improving the yield rate is achieved.

The invention relates to the technical field of power electronic test equipment, and discloses a flat conductor single-layer vertically-wound inductor and a manufacturing method thereof, and the flat conductor single-layer vertically-wound inductor comprises an upper magnetic plate, a lower magnetic plate and at least one parallel magnetic core arranged between the upper magnetic plate and the lower magnetic plate, two ends of the parallel magnetic core are respectively and magnetically connected with the upper magnetic plate and the lower magnetic plate to form a closed magnetic circuit, the winding unit is wound on the periphery of the parallel magnetic core, and the winding unit is of a spiral winding structure formed by a continuous flat conductor through multiple times of inward bending. And the flat conductor is wound on the parallel magnetic core in a vertical winding manner. The flat conductor is subjected to continuous inward bending, so that the effects of simplifying the process and improving the performance can be achieved, the winding process is simplified by the single-layer vertical winding structure, accurate inward bending only needs to be performed at a specific position, the method is suitable for automatic production, the production efficiency and consistency are remarkably improved, the cost is reduced, and the performance is effectively improved.