Molded coil and reactor, method for manufacturing a molded coil, and method for manufacturing a reactor

Abstract

To provide molded coils and reactors, as well as methods for manufacturing molded coils and reactors, that reduce the number of parts and improve production efficiency. [Solution] The molded coil 5 comprises a sensor bracket 72 to which the sensor 4 is attached and installed on the coil 2, and a coil mold resin 91 that covers at least the coil 2 and a part of the sensor 4. The sensor bracket 72 has a fitting groove 76 into which the sensor 4 is inserted. The fitting groove 76 has an opening 77 that surrounds the entire circumference of the body of the sensor 4, and a pair of clamping surfaces 81, 82 that sandwich the sensor 4 from both sides within the fitting groove 76. One of the clamping surfaces 81, 82 is an elastic plate piece 83 that extends along the depth direction of the fitting groove 76, with one end fixed and the other end free. In the installation process, the sensor 4 is press-fitted into the fitting groove 76 while the elastic plate piece 83 is elastically deformed.

Description

Technical Field

[0001] The present invention relates to a molded coil coated with resin, a reactor provided with this molded coil, a method for manufacturing this molded coil, and a method for manufacturing a reactor.

Background Art

[0002] A coil generates magnetic flux according to the number of turns by being energized. Therefore, a coil is used as an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it. A coil is also called a reactor and is used in a wide variety of applications. Fields of use of a coil, also called a reactor, include step-up reactors, series reactors, parallel reactors, current-limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc-extinguishing reactors.

[0003] A step-up reactor is incorporated into an in-vehicle step-up circuit such as a drive system of a hybrid vehicle or an electric vehicle. A series reactor is connected in series to a motor circuit to limit the current at the time of a short circuit. A parallel reactor stabilizes the current sharing between parallel circuits. A current-limiting reactor limits the current at the time of a short circuit. A starting reactor is connected in series to a motor circuit that protects a machine to limit the starting current. A shunt reactor is connected in parallel to a transmission line to compensate for leading reactive power and suppress abnormal voltage. A neutral point reactor is used to connect between a neutral point and the ground to limit the ground fault current flowing at the time of a ground fault accident in a power system. An arc-extinguishing reactor automatically extinguishes the arc generated at the time of a single-phase ground fault in a three-phase power system.

[0004] Reactors are often required to be equipped with sensors that detect physical quantities such as the reactor's temperature. Lead wires extend from the sensors. Connectors are attached to the ends of the lead wires, and the sensors are electrically connected to external devices via the connectors and lead wires. The lead wires consist of a metal wire and a covering made of an insulating material that covers the metal wire. These sensors are protected either by being molded as a standalone unit or by being mounted on a separate sensor cover. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-124267 [Patent Document 2] Japanese Patent Publication No. 2020-035844 [Overview of the project] [Problems that the invention aims to solve]

[0006] Coils may be coated with resin. Coating the coil with resin electrically insulates the core on which the coil is mounted from the coil itself. A coil coated with resin is called a molded coil. The resin surrounding the coil is formed by molding to improve adhesion between the coil and the resin.

[0007] When a sensor is mounted on a coil, the sensor may be coated with resin along with the coil during the molding process used to create the molded coil. The injection pressure of the resin used to mold the coil may cause the lead wires extending from the sensor to be blown over, potentially causing them to break. Additionally, the heat from the resin may melt the coating on the lead wires.

[0008] Therefore, by having the sensor molded together with the lead wires as a single unit, or by mounting the lead wires together with the lead wires in a separate sensor cover, the sensor can be protected from breakage of the lead wires due to the injection pressure of the resin and melting of the lead wire coating due to the heat of the resin.

[0009] However, if the sensor is molded individually or attached to a separate sensor cover, the number of parts in the product increases. Furthermore, the process of molding the sensor individually and attaching the sensor cover to the sensor becomes an additional step.

[0010] The present invention was made to solve the above-mentioned problems, and its objective is to provide molded coils and reactors, as well as methods for manufacturing molded coils and reactors, that reduce the number of parts and improve production efficiency. [Means for solving the problem]

[0011] To solve the above-mentioned problems, the molded coil according to this embodiment comprises a coil, a sensor bracket installed on the coil, a sensor attached to the sensor bracket, and a molded resin covering at least a part of the coil and the sensor. The sensor bracket has a fitting groove into which the sensor is inserted, the fitting groove having an opening that surrounds the entire circumference of the sensor and a pair of clamping surfaces that sandwich the sensor from both sides within the fitting groove, and one of the pair of clamping surfaces is an elastic plate piece that extends along the depth direction of the fitting groove, with one end fixed and the other end of the plate free.

[0012] The sensor is configured such that a lead wire extends from the end opposite to the insertion end into which the sensor is inserted into the fitting groove, and the sensor may be positioned so that the opposite end protrudes from the fitting groove.

[0013] The sensor may have an engaging projection that catches on the free end of the elastic plate piece, and the free end of the elastic plate piece may be pressed against the base of the engaging projection.

[0014] The other of the pair of clamping surfaces may have a curved recess that guides the tip of the sensor into the depth of the fitting groove.

[0015] The sensor bracket has a space extending along the elastic plate piece on the side opposite to the fitting groove, with the elastic plate piece in between, and the space may be larger in volume than the space defined by the curved recess and the sensor.

[0016] The coils have a circular or rounded cross-section that extends perpendicular to the axis, and at least two are provided, arranged side by side with their circumferential surfaces facing each other. The sensor bracket is installed such that the sensor fits into the gap between the two coils, and has a support plate that extends along the axial direction of the coils and is inserted into the gap between the coils. The support plate has a fitting groove and an elastic plate piece, which is cut out along the axial direction of the coils, and the upper part of the plate may be thicker than the lower part of the plate.

[0017] The support plate may have a thickness that increases along the outer circumference of the coil.

[0018] The aforementioned sensor may be a temperature sensor.

[0019] Furthermore, in order to solve the above-mentioned problems, the reactor according to this embodiment comprises the molded coil and an annular core containing a magnetic material and mounted on the molded coil.

[0020] Also, in order to solve the above problems, a method for manufacturing a mold coil according to the present embodiment is a method for manufacturing a mold coil including a coil, a sensor, a sensor bracket for attaching the sensor and arranging it on the coil, and a mold resin for covering at least a part of the sensor and the coil, the method including: an attachment step of attaching the sensor to the sensor bracket; an installation step of installing the sensor bracket on the coil; and a mold molding step of installing the coil with the sensor bracket installed therein into a mold and injecting the mold resin, wherein the sensor bracket has a fitting groove into which the sensor is inserted, the fitting groove having an opening surrounding the entire circumference of the sensor body and a pair of clamping surfaces for clamping the sensor from both sides within the fitting groove, the sensor having a lead wire led out at an end opposite to the insertion-side tip where the sensor is inserted into the fitting groove, and in the attachment step, while elastically deforming the elastic plate piece, the sensor is press-fitted into the fitting groove, and the opposite end from which the lead wire is led out is protruded from the fitting groove and arranged.

[0021] Also, in order to solve the above problems, a method for manufacturing a reactor according to the present embodiment includes an assembly step of attaching the mold coil to a core containing a magnetic material after passing through the method for manufacturing this mold coil.

Advantages of the Invention

[0022] According to the present invention, it is possible to obtain a mold coil and a reactor with a reduced number of parts and good production efficiency, as well as a method for manufacturing the mold coil and the reactor.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view extracting the main configuration of the reactor. [Figure 2] It is a perspective view of a mold coil equipped with a sensor. [Figure 3] It is a perspective view of a mold coil with the coil mold resin omitted. [Figure 4] It is an exploded view of the mold coil. [Figure 5] This is a top view of the top cover. [Figure 6] This is a magnified perspective view of the sensor bracket to which the sensor is attached. [Figure 7] This is a cross-sectional view of the sensor bracket cut to pass through the fitting groove and wiring groove. [Figure 8] This is a perspective view of the sensor bracket from the back. [Figure 9] This is a cross-sectional view of the sensor bracket, cut along the direction perpendicular to the winding shaft. [Figure 10] This shows the first small step of installing the sensor, a cross-sectional view of the sensor bracket cut along the winding shaft so that it passes through the fitting groove and wiring groove. [Figure 11] This shows a second step in installing the sensor, a cross-sectional view of the sensor bracket cut along the winding shaft so that it passes through the fitting groove and wiring groove. [Figure 12] This shows a third sub-step for installing the sensor, a cross-sectional view of the sensor bracket cut along the winding shaft so that it passes through the fitting groove and wiring groove. [Figure 13] This is a perspective view of the sensor bracket and sensor from the back during the molding process. [Figure 14] This is a cross-sectional view of the sensor bracket and coil cut along the entire length of the sensor. [Figure 15] This is a perspective view of a reactor coated with coil mold resin and core mold resin. [Modes for carrying out the invention]

[0024] Hereinafter, molded coils and reactors according to embodiments of the present invention, as well as methods for manufacturing them, will be described with reference to the drawings. In each drawing, thickness, dimensions, positional relationships, ratios, or shapes may be emphasized for ease of understanding, and the present invention is not limited to such emphasis.

[0025] Figure 1 is a perspective view showing the main components of reactor 1. Reactor 1 comprises a coil 2 and a core 3. Coil 2 is fitted into core 3. Coil 2 is a cylindrical wound body from which a conductive wire 21 is drawn. It is an inductor that generates magnetic flux according to the number of turns when current is passed through the conductive wire 21 from the circuit into which reactor 1 is incorporated, thereby introducing inductive reactance into the circuit. Core 3 is a ring-shaped body containing a magnetic material and forms a closed magnetic path that allows the magnetic flux generated by coil 2 to pass through with a permeability higher than that of a vacuum. Therefore, reactor 1 is an electromagnetic component that converts core electrical energy into magnetic energy, stores it, and releases it.

[0026] Coil 2 is formed by winding a conductive wire 21, which is coated with an insulating coating such as enamel, into a rounded rectangular shape. Coil 2 is formed by winding the conductive wire 21 spirally along the winding shaft 22, shifting the winding position of the conductive wire 21 with each turn. The conductive wire 21 of coil 2 is, for example, a flat rectangular wire, and coil 2 is, for example, an edgewise coil. The wide surface of the conductive wire 21 of coil 2 extends in a direction perpendicular to the winding shaft 22 of coil 2. There are no limitations on the type of conductive wire 21; other types of wires such as round wires may also be used. A flatwise coil can also be used as coil 2.

[0027] Core 3 contains a magnetic material such as a powder core, a ferrite core, a metal composite core, or laminated steel sheet. A powder core is made by annealing a powder compact formed by compressing magnetic powder. Magnetic powders mainly consist of iron and include pure iron powder, permalloy (Fe-Ni alloy) mainly consisting of iron, Si-containing iron alloy (Fe-Si alloy), Sendust alloy (Fe-Si-Al alloy), amorphous alloy, nanocrystalline alloy powder, or a mixture of two or more of these powders. A metal composite core is a core formed by kneading and molding magnetic powder and resin.

[0028] The reactor 1 comprises multiple coils 2, for example, two coils 2. The multiple coils 2 are arranged side by side, with their circumferential surfaces facing each other, extending parallel to the winding shaft 22. The reactor 1 is equipped with a sensor 4. The sensor 4 is, for example, a temperature sensor, but is not limited to this as long as it can detect a physical quantity of the reactor 1. That is, the sensor 4 may be an element that detects other physical quantities such as magnetism, electricity, position, vibration, or humidity. When the reactor 1 comprises multiple coils 2, the sensor 4 is inserted, for example, between adjacent coils 2.

[0029] Sensor 4 is shaped by a flat, rectangular cover with flat surfaces on each side, enclosing the element. Lead wires 41 extend from each side of sensor 4, from the end opposite to the insertion end that is inserted into the space between coils 2. Lead wires 41 transmit the output signal of sensor 4 to an external device. A connector 42 is attached to one end of lead wire 41, and sensor 4 is connected to the external device via this connector 42.

[0030] Figure 2 is a perspective view of a molded coil 5 equipped with a sensor 4. As shown in Figure 2, the coil 2 is covered with resin 51 and then fitted into the core 3. Multiple coils 2 may be covered together with resin 51 and then fitted into the core 3. The coil 2 covered with resin 51 is called a molded coil 5. By being covered with this resin 51, the coil 2 is protected from mechanical shock and electrically insulated from the core 3. The sensor 4 is also embedded in the resin 51. However, the sensor 4 is provided by the molded coil 5 and not by the reactor 1. The lead wires 41 are exposed from the resin 51 and are arranged in wiring grooves 73 formed in the resin 51.

[0031] The resin 51 is an insulating material. Examples of insulating materials include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), or composites thereof, and may contain a thermally conductive filler.

[0032] A portion of the resin 51 is formed in the molding process. In the molding process, the coil 2 is placed in a mold, molten resin is injected into the mold, and the molten resin is solidified. The solidified molten resin is the coil mold resin 91. The coil mold resin 91 formed in the molding process has high adhesion to the coil 2. In the molding process, damage to the coil 2 by the mold and peeling of the enamel coating of the conductive wire 21 must be prevented. In addition, in the molding process, irregularities in the coil 2 may be corrected by pressing the mold, or the coil 2 may be compressed by the injection pressure of the molten resin. Furthermore, in the molding process, parts of the coil 2 that are to be exposed may be isolated from the molten resin.

[0033] Therefore, the resin 51 other than the coil mold resin 91 is various covers 61 to 64, as shown in Figures 3 and 4, and the surface of the coil 2 is covered with these covers 61 to 64 in an installation process prior to the molding process.

[0034] Figure 3 is a perspective view of the molded coil 5 with the coil mold resin 91 omitted, and Figure 4 is an exploded view of the molded coil 5. As shown in Figures 3 and 4, the coil 2 is fitted with a top cover 61, an end cover 62, an inner circumferential cylinder 63, and a side cover 64 during the installation process.

[0035] Here, the coil 2 has a pair of end faces 23 perpendicular to the winding shaft 22 and belonging to the circumference of the beginning or end of the winding of the conductive wire 21. The coil 2 also has an inner circumferential surface 24 and, extending along the winding shaft 22, a bottom surface 25, an top surface 26, and side surfaces 27. The four corners corresponding to the boundary between the top surface 26 and the side surfaces 27, and the boundary between the bottom surface 25 and the side surfaces 27, are curved surfaces 28, so that the top surface 26 and the side surfaces 27 are connected by curved surfaces, and the bottom surface 25 and the side surfaces 27 are connected by curved surfaces.

[0036] The side surface 27 is the surface on which two adjacent coils 2 face each other, and the surface located on the opposite side of the coil's winding shaft 22 from these opposing surfaces. The bottom surface 25 is one of the surfaces sandwiched between the pair of side surfaces 27, and the top surface 26 is the surface sandwiched between the pair of side surfaces 27 that is opposite to the bottom surface 25, with the coil's winding shaft 22 in between. The terms "up" and "down" refer to the up and down of the coil 2 within the mold during the molding process, and do not refer to the positional relationship or orientation when the reactor 1 or molded coil 5 is installed in the actual machine.

[0037] The top cover 61 is placed on the top surface 26 of the coil 2. The sensor 4 is attached to the top cover 61 in advance during the installation process. After the sensor 4 is attached, the top cover 61 is placed on the top surface 26 of the coil 2 during the installation process. The end cover 62 is placed on each of the end faces 23 of the coil 2. The inner circumferential cylinder 63 is placed on the inner circumferential surface 24 of the coil 2. The side cover 64 is placed on each side 27 of the coil 2.

[0038] Furthermore, each end face cover 62 and each side cover 64, which are positioned on one end face 23 of each coil 2, are integrally molded products that are connected seamlessly. Each end face cover 62 and the inner circumferential cylinder 63, which are positioned on the other end face 23 of each coil 2, are integrally molded products that are connected seamlessly. The process of fitting the coils 2 into the inner circumferential cylinder 63 is a coil arrangement process in which multiple coils 2 are arranged side by side with their circumferential surfaces facing each other.

[0039] Figure 5 is a top view of the top cover 61. As shown in Figure 5, the top cover 61 comprises a circumferential cover 71 that covers the top surface 26 of one coil 2, a circumferential cover 71 that covers the top surface 26 of the adjacent coil 2, and a sensor bracket 72 positioned between these two coils 2. The top cover 61 is a single molded product in which the two circumferential covers 71 and the sensor bracket 72 are seamlessly connected. Therefore, the installation process of setting the top cover 61 on the coils 2 can also be considered the installation process of setting the sensor bracket 72.

[0040] The sensor bracket 72 extends along the winding shaft 22 and is positioned between the two coils 2. The sensor bracket 72 is equipped with a wiring groove 73. The wiring groove 73 is provided in the sensor bracket 72 and extends along the space between the two coils 2, i.e., along the winding shaft 22. The wiring groove 73 is a wiring path for routing the lead wires 41 and is recessed from the surface of the sensor bracket 72 and has a bottom.

[0041] This wiring groove 73 is defined by a bottom plate 75 and a pair of side wall plates 74 that rise from both sides of the bottom plate 75, i.e., the sides along the winding shaft 22, and connect to the surface of the sensor bracket 72. The height of the side wall plates 74 and the width of the bottom plate 75 are the same as, or greater than, the diameter of the lead wire 41 leading from the sensor 4, and greater than the diameter of that wire.

[0042] A fitting groove 76 is formed within the wiring groove 73. The fitting groove 76 is formed in the bottom plate 75 of the wiring groove 73 and extends deeply from the upper surface 26 to the lower surface 25 of the coil 2, in other words, it extends deeply into the gap between the coils 2. This fitting groove 76 is a hole into which the sensor 4 is inserted.

[0043] The opening 77 of the fitting groove 76, that is, the entrance into which the sensor 4 is inserted, or the bottom plate 75 side of the wiring groove 73, has a tapered shape that gradually narrows in the direction from the wiring groove 73 through to the sensor bracket 72. The narrowest part of the opening 77 of the fitting groove 76 has the same shape and size as the cross-section of the sensor 4, and is large enough to insert the sensor 4. This fitting groove 76 is formed at the end of the wiring groove 73 that is closer to the center of the coil 2 in the direction of the winding shaft 22 of the coil 2.

[0044] Furthermore, the sensor bracket 72 is equipped with a hook 78 near the wiring groove 73 for hooking the lead wire 41 led out from the sensor 4. The hook 78 is positioned on the extension of the wiring groove 73, spaced apart from the wiring groove 73, and on the opposite side from the fitting groove 76, i.e., off the sensor bracket 72. This hook 78 is positioned in a U-shaped gate form that opens in the opposite direction to the recessed shape of the wiring groove 73.

[0045] Figure 6 is an enlarged perspective view of the sensor bracket 72 with the sensor 4 attached. As shown in Figure 6, prior to the installation step of installing the top cover 61 on the coil 2, an installation step of attaching the sensor 4 to the sensor bracket 72 is performed. In the installation step, the sensor 4 is inserted into the fitting groove 76 through the opening 77. The fitting groove 76 is shallower than the total length of the sensor 4, and the end of the sensor 4 fits in with protruding from the fitting groove 76.

[0046] The opening 77 of the fitting groove 76 is tapered. Therefore, when the sensor 4 is slid into the opening 77 of the fitting groove 76, the entire circumference of the body of the sensor 4 is completely enclosed by the opening 77 of the fitting groove 76. The ends of the lead wires 41 of the sensor 4 are left inside the wiring groove 73.

[0047] The lead wire 41 is routed along the bottom plate 75 of the wiring groove 73 toward the hook 78. After the lead wire 41 exits from the end of the wiring groove 73 opposite the mating groove 76, it is hooked onto the hook 78. Since the mating groove 76 is closed by the sensor 4, there is no gap between the sensor 4 and the opening 77 of the mating groove 76. Therefore, the wiring groove 73 and the mating groove 76 through which the lead wire 41 runs are separated by the sensor 4.

[0048] Figure 7 is a cross-sectional view of the sensor bracket 72 cut through the fitting groove 76 and the wiring groove 73, and Figure 8 is a perspective view of the sensor bracket 72 from the back. As shown in Figures 7 and 8, the sensor bracket 72 is equipped with a support plate 8 on the back side of the wiring groove 73.

[0049] The support plate 8 extends in conjunction with the bottom plate 75 of the wiring groove 73. The flat surface 8a of the support plate 8 extends downward from the upper surface 26 to the lower surface 25 of the coil 2, and in the direction along the winding shaft 22. The thickness direction along the short side of the side surface 8b of the support plate 8 is perpendicular to the downward direction from the upper surface 26 to the lower surface 25 of the coil 2.

[0050] The support plate 8 has a U-shaped space 88 formed in it. The U-shaped space 88 starts at the opening 77 of the fitting groove 76 and extends along the plate plane 8a, cutting out a section of the support plate 8. The fitting groove 76 forms part of this U-shaped space 88. In addition to the fitting groove 76, the U-shaped space 88 is composed of opposing parallel space sections 86a and a U-shaped bottom section 88a.

[0051] Of the U-shaped space 88, the fitting groove 76 continues from the opening 77. The fitting groove 76 is formed straight, cutting diagonally into the support plate 8. The end of the fitting groove 76 opposite to the opening 77 does not reach the outer edge of the support plate 8. The total length of the fitting groove 76 is shorter than the total length of the sensor 4. The fitting groove 76 extends diagonally downward from the upper surface 26 to the lower surface 25 of the coil 2, and also diagonally with the winding shaft 22.

[0052] The opposing parallel running space portion 86a is formed to run parallel to the fitting groove 76 at a predetermined distance from it. The U-shaped bottom portion 88a is formed at the end of the opposing parallel running space portion 86a and the fitting groove 76, connecting the extended end of the fitting groove 76 to the opposing parallel running space portion 86a.

[0053] Thus, the U-shaped space 88 first extends straight from the opening 77 of the fitting groove 76 along the plate surface 8a of the support plate 8 as a fitting groove 76. The U-shaped space 88 then bends at the tip opposite the opening 77 of the fitting groove 76 to become a U-shaped bottom 88a, and as a U-shaped bottom 88a, it extends along the plate surface 8a of the support plate 8.

[0054] Then, the U-shaped space 88 bends at the end of the U-shaped bottom portion 88a to become the opposing parallel space portion 86a, which is formed straight along the plate surface 8a of the support plate 8, cutting diagonally upward from the support plate 8. The opposing parallel space portion 86a runs diagonally upward from the lower surface 25 to the upper surface 26 of the coil 2, and extends in a direction diagonally to the winding shaft 22, while running parallel to the fitting groove 76.

[0055] Here, the extended tip of the opposing parallel space 86a does not reach the upper surface of the sensor bracket 72. Also, the opposing parallel space 86a and the fitting groove 76 are in communication at the U-shaped bottom 88a. Furthermore, at least the area near the extended tip of the fitting groove 76 opposite to the opening 77, the U-shaped bottom 88a, and the area near the connection portion of the opposing parallel space 86a with the U-shaped bottom 88a are formed by hollowing out the support plate 8, and the support plate 8 penetrates in the thickness direction.

[0056] Therefore, an elastic plate piece 83 remains between the fitting groove 76 and the opposing parallel space 86a. The elastic plate piece 83 extends along the fitting groove 76. The base of the elastic plate piece 83, which is on the opening 77 side of the fitting groove 76, extends from the support plate 8 and becomes a fixed end 83a, while the end facing the U-shaped bottom 88a, which is the extended tip of the elastic plate piece 83, becomes a free end 83b.

[0057] When this support plate 8 is divided, an elastic plate piece 83 extends between the fitting groove 76 and the opposing parallel space 86a. On the opposite side of the fitting groove 76 from the elastic plate piece 83, a fixed plate piece 84 that cannot be elastically deformed extends. A closing plate piece 87 extends at the end of the fitting groove 76.

[0058] In other words, the fitting groove 76 extends between the fixed plate piece 84 and the elastic plate piece 83. The sensor 4 is held between the gripping surface 81 of the fixed plate piece 84 facing the elastic plate piece 83 and the gripping surface 82 of the elastic plate piece 83 facing the fixed plate piece 84. The gripping surface 82 of the elastic plate piece 83 is along the side of the sensor 4. On the other hand, the imaginary line La in Figure 8 is the side of the sensor 4, and the gripping surface 81 of the fixed plate piece 84 is carved out deeper than this imaginary line La, forming a curved recess 85. The curved recess 85 has a steep incline on the opening 77 side of the fitting groove 76 and gradually becomes shallower towards the extending end of the fitting groove 76.

[0059] When the sensor 4 is fully inserted, that is, when the sensor 4 reaches the closing plate piece 87, the sensor 4 is not in contact with the curved recess 85, and an arc-shaped space 86b is defined between the sensor 4 and the curved recess 85. In comparison with the opposing parallel space 86a and the arc-shaped space 86b, the opposing parallel space 86a is bulging and cut out to have a larger volume than the arc-shaped space 86b.

[0060] Figure 9 is a cross-sectional view of the sensor bracket 72 cut along a direction perpendicular to the winding shaft 22. As shown in Figure 9, when such a support plate 8 is inserted between cylindrical or rounded-corner coils 2, the lower part 8c of the plate is narrower and thinner than the upper part 8d of the plate to match the gap between the coils 2 where the depth is narrower, and the upper part 8d of the plate is wider and thicker than the lower part 8c of the plate to match the gap between the coils 2 where the shallow part is wider. The lower part 8c of the plate is on the deeper side of the gap between the coils 2. The upper part 8d of the plate is on the opening 77 side of the fitting groove 76.

[0061] The process of attaching the sensor 4 to such a sensor bracket 72 will now be described. Figure 10 shows the first sub-step of attaching the sensor 4, and is a cross-sectional view of the sensor bracket 72 cut along the winding shaft 22 through the fitting groove 76 and the wiring groove 73.

[0062] As shown in Figure 10, the tip corner of the sensor 4 is inserted into the opening 77 of the fitting groove 76, and the tip of the sensor 4 is pressed against the curved recess 85. Then, the sensor 4 is pushed in so that its corner scoops out the curved recess 85. The curved recess 85 is a recess that follows the trajectory traced by the tip of the sensor 4 as it moves from a vertical state when the sensor 4 is inserted into the opening 77 to a state where the engaging projection 43 of the sensor 4 engages with the elastic plate piece 83 and is held at an angle in the fitting groove 76. Therefore, the sensor 4 can be easily inserted into the fitting groove 76.

[0063] Next, Figure 11 shows a second step in installing the sensor 4, which is a cross-sectional view of the sensor bracket 72 cut along the winding shaft 22, passing through the fitting groove 76 and the wiring groove 73. When the sensor 4 is inserted toward the back of the fitting groove 76, the elastic plate piece 83 has a fixed end 83a on the opening 77 side of the fitting groove 76 and a free end 83b on the back side of the fitting groove 76, so as the sensor 4 is pressed in, the fitting groove 76 expands due to the elastic deformation.

[0064] Next, Figure 12 shows a third sub-step for mounting the sensor 4, which is a cross-sectional view of the sensor bracket 72 cut along the winding shaft 22 through the fitting groove 76 and the wiring groove 73.

[0065] In the fitting groove 76, the sensor 4 abuts against the closing plate piece 87 and stops. An engaging projection 43 is installed at the tip of the sensor 4, protruding from the side of the body of the sensor 4. When the sensor 4 abuts against the closing plate piece 87, the elastic plate piece 83 returns to its original position, tightening around the sensor 4 due to its elasticity. As the elastic plate piece 83 catches on the engaging projection 43, the risk of the sensor 4 being pushed back out of the fitting groove 76 by the gripping force of the fitting groove 76 is suppressed, and the gripping by the fitting groove 76 can be made stronger.

[0066] In the installation process, which is a later process than the mounting process, the top cover 61 including the sensor bracket 72, the end cover 62, the inner circumferential cylinder 63, and the side cover 64 are installed on the coil 2. After this, the coil 2 is housed in a mold for the molding process.

[0067] In the molding process, molten resin is injected into the mold from the injection gate. However, the sensor 4 is tightly fitted into the opening 77 of the fitting groove 76, reducing the risk of molten resin leaking into the wiring groove 73 from between the opening 77 of the fitting groove 76 and the body of the sensor 4. Therefore, no coil mold resin 91 is formed in the wiring groove 73. The lead wires 41 are exposed from the coil mold resin 91. During the molding process, the lead wires 41 are not strongly buffeted by the injection pressure of the molten resin. As a result, the lead wires 41 can be arranged in the wiring groove 73 without, for example, covering them with resin, and the number of parts in the sensor 4 is reduced by the amount by which the lead wires 41 are exposed.

[0068] Furthermore, since the sensor 4 is tightly fastened to the gripping surfaces 82 and 81 of the fitting groove 76, the molten resin is prevented from rising to the vicinity of the opening 77 of the fitting groove 76. The engagement between the engaging projection 43 and the elastic plate piece 83 causes the sensor 4 to be displaced in the direction of being pushed out of the fitting groove 76 by the molten resin, and the risk of the tightening by the gripping surfaces 82 and 81 of the fitting groove 76, as well as the tightening by the opening 77 of the fitting groove 76, loosening is reduced.

[0069] Figure 13 is a perspective view of the sensor bracket 72 and sensor 4 from the back during the molding process. As shown in Figure 13, the opposing parallel space 86a has a larger volume than the arc-shaped space 86b defined by the sensor 4 and the curved recess 85. Therefore, more molten resin enters the opposing parallel space 86a than the arc-shaped space 86b. As a result, the molten resin in the opposing parallel space 86a strongly adheres the elastic plate piece 83 to the sensor 4. The free end 83b of the elastic plate piece 83 bites firmly into the base of the engaging projection 43 and presses against it, making it even more difficult for the sensor 4 to come off the fitting groove 76.

[0070] Figure 14 is a cross-sectional view of the sensor bracket and coil cut along the entire length of the sensor. As shown in Figure 14, the lower part 8c of the support plate 8 is the same thickness as or slightly thicker than the width of the sensor 4. Therefore, when the sensor 4 is inserted into the fitting groove 76, the surface of the sensor 4 and the surface of the support plate 8 are flush, or the surface of the sensor 4 is positioned slightly lower than the surface of the support plate 8 and hidden from the surface of the support plate 8.

[0071] Therefore, the sensor 4 can be hidden by the support plate 8, and the injection pressure applied to the sensor 4 is reduced. As a result, the injection pressure of the molten resin applied to the sensor 4 is reduced, which suppresses the sensor 4 from being pushed around and shifting position due to the injection pressure. If the positional shift of the sensor 4 is suppressed, the risk of molten resin leaking into the wiring groove 73 from between the opening 77 of the fitting groove 76 and the body of the sensor 4 is further reduced.

[0072] On the other hand, as shown in Figure 14, the upper part 8d of the support plate 8 is thicker towards the top so as not to increase the distance between the curved surface 28 of the coil 2 and the flat surface 8a of the support plate 8. Therefore, the molten resin does not forcefully eject between the coil 2 and the support plate 8, but slowly fills the space between the coil 2 and the support plate 8. Consequently, leakage of the molten resin from between the coil 2 and the support plate 8 into the wiring groove 73 and contact with the lead wires 41 is suppressed.

[0073] As described above, the molded coil 5 comprises a coil 2, a sensor bracket 72 installed on the coil 2, a sensor 4 attached to the sensor bracket 72, and a coil mold resin 91 covering at least the coil 2 and a portion of the sensor 4. The sensor bracket 72 has a fitting groove 76 into which the sensor 4 is inserted. The fitting groove 76 has an opening 77 that surrounds the entire circumference of the body of the sensor 4, and a pair of clamping surfaces 81 and 82 that sandwich the sensor 4 from both sides within the fitting groove 76. One of the pair of clamping surfaces 81 and 82 extends along the depth direction of the fitting groove 76, with one end fixed and the other end of the plate being a free elastic plate piece 83.

[0074] In this molded coil 5, the opening 77 of the fitting groove 76 into which the sensor 4 is inserted surrounds the entire circumference of the sensor 4, with the aim of suppressing the leakage of molten resin into the area where the lead wire 41 is located during the molding process. Therefore, in the installation process during the manufacturing of this molded coil 5, the elastic plate piece 83 is elastically deformed while the sensor 4 is inserted into the fitting groove 76, and the opposite end from which the lead wire 41 is led out is positioned to protrude from the fitting groove 76. This ensures that the sensor 4 is more securely surrounded by the opening 77 of the fitting groove 76, and even if the circumference of the sensor 4 is tightened more firmly in the fitting groove 76, the presence of the elastic plate piece 83 allows the sensor 4 to be inserted into the fitting groove 76.

[0075] Therefore, with this molded coil 5, leakage of molten resin into the area where the lead wire 41 is located during the molding process is more reliably suppressed. As a result, the sensor 4 can be protected from breakage of the lead wire 41 due to resin injection pressure and melting of the coating of the lead wire 41 due to the heat of the resin, without the need to mold the lead wire 41 or attach it to a separate sensor cover. Furthermore, the molding of the lead wire 41 and a separate sensor cover can be eliminated, reducing the number of parts and increasing production efficiency.

[0076] Furthermore, the sensor 4 has an engaging projection 43 that catches on the free end 83b of the elastic plate piece 83, and the free end 83b of the elastic plate piece 83 is pressed against the base of the engaging projection 43. This makes it difficult for the sensor 4 to come out of the fitting groove 76. Therefore, even if the force required to press-fit the sensor 4 is increased, the sensor 4 is less likely to return to the direction of disengaging from the fitting groove 76, and the risk of a gap forming between the body of the sensor 4 and the opening 77 of the fitting groove 76 can be reduced.

[0077] Furthermore, the other of the pair of clamping surfaces 81 and 82 has a curved recess 85 that guides the tip of the sensor 4 to the back of the fitting groove 76. As a result, even if the opening 77 and the fitting groove 76 are narrowed and the force required to insert the sensor 4 is increased, it becomes easier to press-fit the sensor 4 into the fitting groove 76. Consequently, the body of the sensor 4 can be more tightly gripped by the opening 77 of the fitting groove 76, and leakage of molten resin into the area where the lead wire 41 is located during the molding process can be more reliably suppressed.

[0078] Furthermore, the sensor bracket 72 has an opposing parallel space portion 86a that extends along the elastic plate piece 83 on the side opposite to the fitting groove 76, with the elastic plate piece 83 in between. This opposing parallel space portion 86a has a larger volume than the arc-shaped space portion 86b defined by the curved recess 85 and the sensor 4.

[0079] As a result, the amount of molten resin flowing in during the molding process is greater in the opposing parallel space 86a than in the arc-shaped space 86b. Therefore, the molten resin in the opposing parallel space 86a presses the elastic plate piece 83 towards the sensor 4, allowing the free end 83b of the elastic plate piece 83 to bite more firmly into the base of the engaging projection 43 and make contact.

[0080] Furthermore, the coil 2 has a rounded cross-section that extends perpendicularly along the winding shaft 22. At least two coils 2 are provided and arranged side by side with their circumferential surfaces facing each other. In this case, the sensor bracket 72 is installed so that the sensor 4 fits into the gap between the two coils 2. The sensor bracket 72 has a support plate 8 that extends along the direction of the winding shaft 22 of the coil 2 and is inserted into the gap between the coils 2. The support plate 8 has a fitting groove 76 and an elastic plate piece 83, which are cut out along the direction of the winding shaft 22 of the coil 2, and the upper part 8d of the plate is thicker than the lower part 8c of the plate.

[0081] As a result, the distance between the support plate 8 and the circumferential surface of the coil 2 does not increase, and the molten resin slowly fills the space between the coil 2 and the support plate 8. This prevents the molten resin from leaking out from between the coil 2 and the support plate 8 into the wiring groove 73 and coming into contact with the lead wire 41.

[0082] Although coil 2 is shown as a rounded-square tube, it may also be cylindrical. Even in the case of a cylindrical coil 2, the upper part 8d of the support plate 8 should be made thicker towards the top so that the distance between the curved surface 28 of coil 2 and the flat surface 8a of the support plate 8 does not increase. In addition, coil 2 may be cylindrical, rounded-square tube, or square tube.

[0083] The support plate 8 is thicker on the upper 8d side than on the lower 8c side, and the change in thickness should increase along the outer shape of the coil 2. However, even if it does not perfectly follow the outer shape of the coil 2, it will prevent the molten resin from leaking from between the coil 2 and the support plate 8 into the wiring groove 73 and coming into contact with the lead wires 41.

[0084] Such a molded coil 5 can be used in the assembly process of the reactor 1. Figure 15 is a perspective view of the reactor 1 covered with coil mold resin 91 and core mold resin 92.

[0085] As shown in Figure 15, the reactor 1 is manufactured through an assembly process in which the molded coil 5, produced by this manufacturing method, is attached to a core 3 covered with core mold resin 92. The annular core 3 is composed of divided parts, and the molded coil 5 is fitted into the parts of the core 3 before the core 3 is assembled into an annular shape. The core mold resin 92 may be formed by molding with the core 3 housed in a mold, or the core 3 and molded coil 5 may be housed in a mold and molded by inserting the core 3 and molded coil 5 to integrate them with the core mold resin 92.

[0086] The embodiments of the present invention described above are merely examples and are not limited to those embodiments. The above embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiments and their variations are included within the scope of the present invention. [Explanation of Symbols]

[0087] 1 Reactor 2 coils 21 Conductive wire 22 reel spindles 23 End face 24 Inner surface 25 Bottom side 26 Top side 27 Side view 28 Curved surface 3 cores 4 sensors 41 Lead wires 42 connectors 43 Engagement protrusion 5 Molded Coils 51 Resin 61 Top cover 62 End face cover 63 Inner cylinder 64 Side cover 71 Peripheral cover 72 Sensor Bracket 73 Wiring groove 74 Side wall panel 75 Bottom plate 76 Fitting groove 77 Aperture 78 hooks 8 Support plate 8a plate plane 8b Plate side 8c lower plate 8d upper part of board 81 Narrow gripping surface 82 Narrow holding surface 83 Elastic plate 83a fixed end 83b free end 84 Fixed plate piece 85 Curved recess 86a Opposing parallel space section 86b Arc-shaped space 87 Occlusion plate piece 88 U-shaped space 88a U-shaped bottom 91 Coil mold resin 92 Core mold resin

Claims

1. Coil and, A sensor bracket installed on the coil, A sensor attached to the aforementioned sensor bracket, A molded resin covering at least the coil and a portion of the sensor, Equipped with, The sensor bracket has a fitting groove into which the sensor is inserted. The aforementioned fitting groove is The aforementioned sensor has an opening that surrounds the entire circumference of its body, A pair of clamping surfaces that sandwich the sensor from both sides within the fitting groove, It has, One of the pair of clamping surfaces extends along the depth direction of the fitting groove, with one end fixed and the other end of the plate being a free elastic plate piece. A molded coil characterized by the following features.

2. The sensor has a lead wire leading out from the end opposite to the insertion end into which the sensor is inserted into the fitting groove. The sensor is positioned such that its opposite end protrudes from the fitting groove. A molded coil according to claim 1, characterized by the following:

3. The sensor has an engaging projection that hooks onto the free end of the elastic plate piece, The free end of the elastic plate piece is pressed against the base of the engaging projection. A molded coil according to claim 1, characterized by the following:

4. The other of the pair of clamping surfaces has a curved recess that guides the insertion-side tip of the sensor to the back of the fitting groove. A molded coil according to claim 1, characterized by the following:

5. The sensor bracket has a space extending along the elastic plate piece on the side opposite to the fitting groove, with the elastic plate piece in between. The aforementioned space has a larger volume than the space defined by the curved recess and the sensor. A molded coil according to claim 4, characterized by the above.

6. The aforementioned coil is The cross-section extending perpendicular to the axis has a circular or rounded shape, At least two are provided, arranged side by side with their circumferential surfaces facing each other, The aforementioned sensor bracket is The sensor is installed so as to fit into the gap between the two coils. The coil has a support plate that extends along the axial direction of the coil and is inserted into the gap between the coils, The aforementioned support plate is The coil is notched along its axial direction, and has the fitting groove and the elastic plate piece. The top of the board is thicker than the bottom of the board. A molded coil according to claim 1, characterized by the following:

7. The support plate has an increasing thickness along the outer circumference shape of the coil. A molded coil according to claim 6, characterized by the above.

8. The aforementioned sensor is a temperature sensor. A molded coil according to claim 1, characterized by the following:

9. A molded coil according to any one of claims 1 to 8, An annular core containing a magnetic material, which is mounted on the molded coil, To be equipped, A reactor characterized by the following.

10. A method for manufacturing a molded coil comprising a coil, a sensor, a sensor bracket for mounting the sensor and placing it on the coil, and a molded resin covering at least a portion of the sensor and the coil, The installation process involves attaching the aforementioned sensor to the sensor bracket, Installation step of installing the sensor bracket on the coil, A molding process in which the coil on which the sensor bracket is installed is placed in a mold and the molding resin is injected, Equipped with, The sensor bracket has a fitting groove into which the sensor is inserted. The aforementioned fitting groove is The aforementioned sensor has an opening that surrounds the entire circumference of its body, A pair of clamping surfaces that sandwich the sensor from both sides within the fitting groove, It has, One of the pair of clamping surfaces is an elastic plate piece that extends along the depth direction of the fitting groove, with one end fixed and the other end of the plate free. The sensor has a lead wire leading out from the end opposite to the insertion end into which the sensor is inserted into the fitting groove. In the mounting process, the elastic plate piece is elastically deformed while the sensor is pressed into the fitting groove, and the opposite end from which the lead wire is led out is positioned to protrude from the fitting groove. A method for manufacturing molded coils characterized by the following.

11. The method for manufacturing a molded coil according to claim 10 includes an assembly step of mounting the molded coil onto a core containing a magnetic material. A method for manufacturing a reactor characterized by the following.

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