Transformer components and methods for manufacturing the same transformer components

Abstract

A transformer component (1) comprising at least one winding (2) in which a conductor (5) having an insulating coating (6) is wound once, and a molded body (4) in which the conductor (5) having an insulating coating (6) is at least partially embedded.

Description

Technical Field

[0001] The present invention relates to transformer components, particularly to transformer components for low voltage. The primary winding and / or secondary winding of the component may be composed of one turn using a single wire.

Background Art

[0002] Transformer components in which a coil formed from a solid copper bar is embedded in a molded body are known for ensuring galvanic insulation, mechanical and electrical safety, and coil positioning. To meet the electrical insulation standards for high voltages with the risk of electric shock, the molded body requires a predetermined minimum wall thickness. The wall thickness and the position of the coil need to be strictly controlled during injection molding and / or during inspection after molding. This is because even a slight movement or deformation of the copper bar during injection molding may cause the minimum wall thickness not to be met.

[0003] Also, cracks and air bubbles in the molded body may reduce the insulation performance. To prevent cracks and air bubbles in the molded body, the process parameters must be strictly controlled. For example, setting the injection pressure appropriately, preheating the injection tool and the copper bar, and appropriately setting the injection position and the number of injection points to optimize the molding flow. Further, by fixing the copper bar with an adhesive or a fixture in the mold device, the movement of the copper bar during injection molding can be prevented. The fixture is removed from the injection molding die device at the end of the injection molding process. As a result, flow lines remain and cracks may occur in the molded body. To insulate such weak points, additional bonding points may be provided. Also, structural auxiliary materials such as tapes, caps, or positioning members may be used to separate the winding from the core and / or other windings.

[0004] Alternatively, a wall thickness larger than the required wall thickness may be provided so as to meet the standards even when there is a slight displacement or deformation of the copper bar.

[0005] Each of these methods requires additional steps and may increase the dimensions of the transformer components. Inspection of the molded resin components also requires additional steps, such as X-ray inspection to verify the winding position and measure the minimum wall thickness of the molded body around the windings. [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide transformer components with improved quality. [Means for solving the problem]

[0007] In one aspect, the transformer component comprises at least one winding in which an insulating wire is wound once, and a molded body in which the wire is at least partially embedded.

[0008] The winding may be a primary winding and / or a secondary winding. For example, one of the multiple windings may be formed with one turn of conductor wire, and the other with multiple turns of conductor wire. The conductor forming one turn may have a larger diameter than the conductor forming multiple turns.

[0009] Transformer components may be suitable for low-voltage applications, for example. Transformer components may also be used for overload detection.

[0010] When using wires with insulating coatings instead of bare wires, galvanic insulation is ensured by the insulating coatings. Therefore, the molded body does not need to have the required insulation properties, and it simply serves to mechanically position the wires and protect them from damage during handling or core assembly, for example.

[0011] This allows for a reduction in the wall thickness of the molded part. In one example, the wall thickness may be minimized to, for example, 0.2 mm. Furthermore, since setting the minimum wall thickness is not a critical factor, additional measures to prevent movement or bending of the lead wire during injection molding, and inspection of the molded part after molding, are not required. In addition, it is not necessary to precisely position the lead wire within the mold.

[0012] As the conductor, at least double-insulated or triple-insulated wire may be used. Each sheath can be formed by an extrusion process around the wire core. For example, a double-insulated wire may comprise a first layer containing ETFE as the material and a second layer containing FEP as the material. A triple-insulated wire may comprise a first layer containing ETFE as the material, a second layer containing FEP as the material and a third layer containing PFA as the material. Generally, any type of insulated conductor is acceptable as long as it meets safety standards.

[0013] The material used for the molded body does not need to have any special insulating properties. Therefore, the material can be selected based on factors such as cost and mechanical properties. For example, it may be a thermoplastic or thermosetting material.

[0014] In one embodiment, the conductor may be held by a retaining member to ensure a stable position during injection molding. The retaining member may remain inside the transformer component after injection molding. For example, the conductor may be inserted into the retaining member, and the retaining member may be fixed to the mold before injection molding.

[0015] In another aspect, the method for manufacturing a transformer component comprises the steps of preparing a conductor having an insulating coating and forming a single turn, and embedding the insulating conductor at least partially within a molded body by injection molding. The transformer component may have any of the aforementioned structural and / or functional characteristics.

[0016] The conductor may be housed in a retaining member fixed within the mold to ensure a stable position during injection molding.

[0017] The above method may further include the steps of removing the insulating coating from the wire end and / or bending the wire end. The step of removing the insulating coating may be performed after injection molding. The step of bending the wire end may be performed after the removal of the insulating coating. Alternatively, the steps of removing the insulating coating from the wire end and / or bending can be performed before injection molding. Other windings may be provided in the winding portion of the molded body.

[0018] This disclosure relates to multiple aspects of the invention. Each component described in relation to one of the multiple aspects is disclosed herein as applicable to the other aspects, even if that component is not explicitly described in the other aspects.

[0019] Further features, improvements, and innovations will become apparent from the following description of exemplary embodiments, which will be explained with reference to the drawings. [Brief explanation of the drawing]

[0020] [Figure 1] Figure 1A is a perspective view of a transformer component according to one embodiment. Figure 1B shows the conductors forming the windings in the transformer component shown in Figure 1A. Figure 1C is a cross-sectional view of the conductors located within the molded body of the transformer component shown in Figure 1A. [Figure 2] Figures 2A to 2D show the manufacturing process of a transformer component according to one embodiment. [Figure 3] Figure 3 is a longitudinal cross-sectional view of the transformer components in the state shown in Figure 2B. [Figure 4] Figures 4A to 4C show the manufacturing process of transformer components according to another embodiment. [Modes for carrying out the invention]

[0021] In drawings, elements having the same structure and / or function may be given the same reference numeral. Please understand that the embodiments shown in the drawings are schematic diagrams for illustrative purposes and do not necessarily accurately represent actual dimensions or scale.

[0022] Figure 1A shows a transformer component 1 including a winding 2. The winding 2 may be a primary winding or a secondary winding. At least a part of the winding 2 is encapsulated within a molded body 4. The molded body 4 has an opening 7 for inserting a magnetic core such as a ferrite core. The molded body 4 may be referred to as a bobbin. The molded body 4 has a winding portion 3 for applying a secondary winding. The secondary winding may be formed from a plurality of turns of a conducting wire such as a copper wire having an insulating coating conforming to safety standards, or an enamel-coated copper wire (such as Polyurethan G2). The molded body 4 includes an insulating material such as resin.

[0023] The transformer component 1 may be configured for low voltage or medium voltage. As an example, the operating voltage may be in the range of 300 to 1200V. The frequency range may typically be 50 to 500 kHz. The transformer component 1 may be used, for example, for overload detection.

[0024] The winding 2 is formed by one turn of an insulated conducting wire 5. The conducting wire 5 terminates with two pins 8 and 9 for electrically connecting the winding 2.

[0025] The conducting wire 5 has its own insulating coating 6, and the insulating coating 6 covers the conducting wire 5 in at least a part of the molded body 4. The insulating coating 6 provides galvanic insulation and safety insulation for the conducting wire 5. In particular, the winding 2 is galvanically insulated from the magnetic core and the secondary winding by the insulating coating 6. The molded body 4 positions the conducting wire 5 and mechanically protects the conducting wire 5 from damage that may occur during operation, during core assembly, and / or due to environmental factors, and further physically separates it from the magnetic core and other windings.

[0026] However, it is not necessary to ensure the required galvanic insulation by the molded body 4. Therefore, it is not necessary to set a minimum wall thickness for the molded body 4 to ensure galvanic insulation and meet safety requirements in accordance with standards related to electrical safety such as IEC standards (such as IEC61558). Also, it is not necessary to use special materials for the molded body 4.

[0027] Conventionally, when using bare conductors without insulating coatings, it was necessary to provide the molded body 4 with a minimum wall thickness, for example, 2 mm at an operating voltage of 1000 V, in order to meet the highest safety standards for reinforced insulation compliant with safety standards such as IEC61558. Achieving such insulation is difficult and also leads to an increase in the size of the transformer component 1. Since the conductor protrudes from the molded body 4 at its end, the minimum wall thickness is determined not by the conductor end but by the wall thickness around the conductor turn.

[0028] By using an insulated conductor 5 embedded within the molded body instead of an uninsulated conductor, the transformer component 1 can be miniaturized while ensuring or exceeding the required insulation characteristics. In particular, the insulation necessary to prevent electric shock is already ensured by the insulating coating 6, and the molded body 4 only needs to protect the insulated conductor from damage during core assembly, etc., and hold the conductor in place when mounted on a PCB, for example, via a through-hole. As an example, the wall thickness of the molded body, i.e., the minimum distance from the outside of the conductor 5 to the outside of the molded body 4, can be 0.4 mm instead of the conventional 2 mm. Additional components such as tape, housing, sealant, or cap to mechanically protect the insulating coating of the winding 2 are unnecessary.

[0029] Furthermore, cracks or bubbles in the molded material do not cause the insulation voltage between the transformer winding and the other winding to fall below the required level, nor do they reduce the partial discharge withstand capability. Therefore, even if there are air gaps or bubbles around the insulated conductor, the electrical insulation standards are met. For this reason, detailed inspection of cracks or bubbles in the molded material is unnecessary. Transformer component 1 does not require structural auxiliary members such as tapes, caps, or positioning devices to separate the windings from each other.

[0030] Furthermore, since it is not necessary to inspect the thickness and the precise position of the insulated conductor 5 during or after manufacturing, the manufacturing process can be simplified.

[0031] Figure 1B shows the conductor 5 as it is arranged inside the molded body 4. For ease of explanation, the molded body 4 is not shown here. The conductor 5 is U-shaped. This shape can also be described as bracket-shaped. Inside the molded body 4, the conductor 5 has its own insulating coating 6. Pins 8 and 9 protrude from the molded body 4 and do not have the insulating coating 6. Part of the insulating coating 6 may also be present on the outside of the molded body 4.

[0032] Figure 1C shows a cross-sectional view of the conductor 5 and its surroundings within the molded body 4. The wire core 7 is surrounded by an insulating sheath 6. The insulating sheath 6 may be triple-insulated, i.e., a three-layer insulating sheath. The wire core 7 may be Litz wire, as long as the outer insulating sheath meets the required safety standards. The material of the insulating sheath 6 may differ from the material of the molded body 4.

[0033] To obtain the same required insulation properties, the minimum thickness of the insulating coating 6 can usually be made significantly thinner than in the case of a solid molded body 4. Because the required insulation properties are obtained by the insulating coating 6, the entire component can be miniaturized.

[0034] Figures 2A to 2D show the manufacturing process of transformer component 1, in particular the transformer component shown in Figure 1A.

[0035] As shown in Figure 2A, in the first step, a conductor 5 is prepared to form the winding 2. The conductor 5 may also form a secondary winding. The conductor 5 is equipped with an insulating coating 6. The insulating coating 6 extends along the entire length of the conductor 5. The conductor 5 is U-shaped.

[0036] In Figure 2B, the conductor 5 is placed inside the mold device, and a portion of it is embedded in the molded body 4 by injecting the material for the molded body 4 into the mold device. As an example, one-shot injection molding may be used. The conductor 5 may be completely covered by the molded body 4, except for the conductor ends 11 and 12. The conductor ends 11 and 12 protrude from the molded body 4 and remain insulated along their entire length.

[0037] In the same process, for example, pins for secondary windings may be placed in the mold device and partially embedded by injection molding. The secondary pins may take the form of, for example, a lead frame.

[0038] In the process shown in Figure 2C, the insulating coating 6 is removed from the wire ends 11 and 12, thereby forming the non-insulated pins 8 and 9 for the electrical connection of the winding 2. As an example, laser stripping may be used to remove the insulating coating 6.

[0039] In the process shown in Figure 2D, pins 8 and 9 are bent into an L-shape, for example. Similarly, the pins for the secondary winding may also be L-shaped. The wire ends of the secondary winding may be connected to each pin. For example, the wire ends of other windings may be wrapped around each pin and secured by soldering or adhesive. Transformer component 1 may be mounted on the PCB, for example, by surface mounting or through-hole mounting.

[0040] When the wire ends 11 and 12 are used as pins 7 and 8, creepage distance and clearance are ensured by stable positioning within the molded body. As a result, tolerances and dimensions for the wire ends can be reduced compared to winding pins, which require additional space for winding and soldering. This allows for overall miniaturization.

[0041] Furthermore, the wire ends 11 and 12 may be cut to make pins 8 and 9 the desired length. The bending and / or cutting steps are optional and may not be necessary depending on the transformer design.

[0042] Figure 3 is a longitudinal cross-sectional view of the transformer components in the process shown in Figure 2B. The minimum wall thickness from the outer surface of the insulated conductor 5 to the surface of the molded body 4 is, for example, 1 mm or less. As an example, the minimum wall thickness may be 0.2 mm. The minimum wall thickness a may be the distance to the surface adjacent to the magnetic core of the molded body 4. The thickness of the conductor may be, for example, about 1 mm. In this figure as well, multiple pins 10 for the secondary winding are shown.

[0043] Figures 4A to 4C show the manufacturing process of transformer component 1 according to another embodiment. The conductor 5 can have the configuration described above and is equipped with an insulating coating 6.

[0044] As shown in Figure 4A, a retaining member 13 is used to reliably position the conductor 5, which has an insulating coating 6, within the mold. The retaining member 13 may be made of resin.

[0045] As shown in Figure 4B, the wire 5 is inserted into the retaining member 13, and then positioned together with the retaining member 13 within the mold. The retaining member 13 may be fixed to the mold. The retaining member 13 can also be fixed to the mold when inserting the wire 5 into the retaining member 13. After that, a molded body 4 is formed around the wire 5 and the retaining member 13 by injection molding.

[0046] Figure 4C shows the obtained transformer component 1, in which the retaining member 13 is part of the transformer component 1. The conductor ends 11 and 12 protrude from the molded body 4, and the insulating coating of the conductor ends 11 and 12 may be removed before or after injection molding. The bending process is also the same as in other embodiments. [Explanation of Symbols]

[0047] 1. Transformer components 2 windings 3. Winding section for other windings 4 Molded body 5 conductor 6. Insulating coating 7 Conductor core 8. Pin 1 9. Pin 2 10 Other winding pins 11 Conductor end 12 Conductor end 13 Retaining member a Minimum wall thickness

Claims

1. A winding (2) is formed by winding a conductor (5) having an insulating coating (6) around it once, A molded body (4) in which the conductor (5) having the insulating coating (6) is at least partially embedded, A transformer component (1) equipped with [a specific feature].

2. The transformer component (1) according to claim 1, wherein the minimum wall thickness (a) from the outside of the insulating coating (6) to the surface of the molded body (4) is 1 mm or less.

3. The transformer component (1) according to any of the above claims, wherein the conductor (5) is at least a double-insulated wire or a triple-insulated wire.

4. The transformer component (1) according to any of the above claims, wherein the material of the molded body (4) includes a thermoplastic material or a thermosetting material.

5. The transformer component (1) according to any of the above claims, wherein the winding (2) is a primary winding and / or a secondary winding.

6. The transformer component (1) according to any of the above claims, wherein the winding (2) is U-shaped.

7. The transformer component (1) according to any of the above claims, wherein the conductor (2) is installed on the retaining member (13), and the retaining member (13) and the conductor (2) are at least partially embedded in the molded body (4).

8. A method for manufacturing a transformer component (1) according to any of the above claims, A) A step of preparing a conductor (5) having an insulating coating (6) and forming one turn, B) The step of embedding the conductor (5) in the molded body (4) at least partially by injection molding, A manufacturing method that includes the following features.

9. In the manufacturing method described in claim 8, C) Step of removing the insulating coating (6) from the conductor (5) at the conductor ends (11, 12), A manufacturing method that further enhances this feature.

10. In the manufacturing method described in claim 8 or 9, D) A step of bending the ends (11, 12) of the conductor, A manufacturing method that further enhances this feature.

11. The manufacturing method according to any one of claims 8 to 10, wherein the conductor (5) is held by a holding member (13) in order to ensure a stable position within the mold during injection molding.

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