JP7829632B2 - Reactor manufacturing method - Google Patents

Description

This invention relates to a reactor and a method for manufacturing a reactor.

A reactor is a passive element consisting of a coil and a core that converts electrical energy into magnetic energy for storage and release. Reactors are used in a wide variety of applications. Typical reactors include boost reactors, series reactors, parallel reactors, current-limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc-extinguishing reactors.

Boost reactors are incorporated into boost circuits for automotive applications such as the drive systems of hybrid and electric vehicles. Series reactors are connected in series with motor circuits to limit current during short circuits. Parallel reactors stabilize current distribution between parallel circuits. Current-limiting reactors are connected to limit current during short circuits. Starting reactors are connected in series with motor circuits to protect machinery and limit starting current. Shunt reactors are connected in parallel with transmission lines to compensate for leading reactive power and suppress abnormal voltages. Neutral point reactors are connected between the neutral point and ground to limit ground fault current during ground faults in power systems. Arc extinguishing reactors automatically extinguish arcs that occur during single-line ground faults in three-phase power systems.

In this reactor, the core is coated with a core coating resin, and the coil is attached to the core via the core coating resin. Furthermore, the reactor body, which consists of the core and coil, is also coated with molding resin, at least on the coil. The core coating resin and molding resin provide insulation between the core and coil, and between the coil and external components. They also protect the core and coil from direct physical contact, preventing damage to, for example, the enamel coating on the coil.

For molded resins, injection molding is frequently used, in which the reactor body is housed in a mold and resin is injected into the mold. For example, there are reactors where a portion of the coil is left uncovered by resin, leaving a portion of the coil exposed. Exposing a portion of the coil allows for visual inspection of the coil's condition and ensures proper heat dissipation. In such reactors, the mold is pressed against the coil surface, or a frame is pressed against the coil surface, to prevent resin from entering the area intended for exposure (see, for example, Patent Documents 1 to 3).

The coil is created by spirally winding conductive wire along a winding axis, shifting the winding position with each turn, resulting in a cylindrical shape with an alternating configuration of four flat surfaces and four curved surfaces. Due to manufacturing precision requirements, the coil surface is not always perfectly smooth, and twists occur on the surface. Therefore, even when attempting to tightly seal the mold or frame to the coil, gaps may form between the mold/frame and the coil surface. This gap can allow resin to penetrate, potentially causing burrs to form on the exposed surface.

To address this problem, the mold or frame is pressed firmly against the coil surface to correct any irregularities or twists. The reason for pressing the coil through the frame is that pressing the coil directly with the mold to correct these irregularities would damage the coil, for example, causing the enamel coating to break.

Here, a connecting coil may be arranged in the reactor. To obtain a high inductance value in the high-current region, the connecting coil is formed by arranging two coils in parallel and connecting them so that the direction of the current flowing through each coil is opposite to that of the other coil. This connecting coil may be formed from a single conductive wire. That is, the first coil is formed using one region of a single conductive wire, and the second coil is formed using the other region of the same conductive wire. The remaining portion of the conductive wire between the regions used to form the two coils becomes the connecting portion that links the two coils (see, for example, Patent Document 4).

When two separate coils are mounted on a reactor, four terminals are required, increasing the material cost of the reactor. Furthermore, when two separate coils are connected, the ends of the two coils must be welded, increasing the labor costs. On the other hand, a connected coil requires only two terminals and does not require welding of the ends of the two coils.

Patent No. 5869518 Japanese Patent Publication No. 2015-130410 Japanese Patent Publication No. 2018-011019 Patent No. 4812641

The conductive wire used as the material for coils is flat rectangular wire. One method of winding coils is edgewise winding. In edgewise winding, the conductive wire is wound so that its wide surface extends perpendicular to the coil's winding axis. Compared to flatwise winding, edgewise winding has the advantage of shortening the winding axis direction for the same number of turns.

In a connected coil, when flat rectangular wire is used for the conductive wire and edgewise winding is employed, the wire extends perpendicular to the winding axis. The connecting portion between two coils, when stretched straight from one end of each coil to the other, expands to a wide surface perpendicular to the winding axis. On the other hand, when forming molded resin, to suppress resin leakage, the surface of the coil is strongly pressed with a mold or frame to correct surface irregularities and twists. The direction in which the mold or frame presses the coil is also perpendicular to the winding axis.

If the connecting portion of the connecting coils is not somewhat flexible in the direction in which the mold or frame presses against the coil surface, the force will not be transmitted to the coil, and the unevenness and twisting of the coil surface cannot be corrected. However, the connecting portion has a wide surface aligned with the direction in which the mold or frame presses against the coil surface. When considering the force pressing on one coil, the connecting portion can be considered as a cantilever beam with the end of that coil as the point of application of force. The second moment of area of this connecting portion is proportional to the product of the cube of the width of the wide surface and the width of the narrow surface.

Therefore, in reactors employing connected coils made by edgewise winding a single conductive wire, the connecting section acts as a rigid beam, reducing the effect of correcting surface irregularities and twists in the coil. This makes it impossible to eliminate the risk of resin leakage between the coil and the mold or frame during molding, potentially causing burrs to form on the exposed surface.

This invention was made to solve the above-mentioned problems, and its objective is to provide a reactor and a method for manufacturing the same in which burr generation is suppressed even when a connecting coil is used.

To solve the above-mentioned problems, the present invention provides a method for manufacturing a reactor, comprising: a coil manufacturing step of creating a connecting coil by winding multiple spaced locations in a single conductive wire using edgewise winding; and a molding step of mounting the connecting coil onto a core and then covering at least the connecting coil with resin, wherein in the coil manufacturing step, a first coil and a second coil are created within the connecting coil, the first coil and the second coil are arranged with their winding axes parallel to each other, a connecting portion connecting the first coil and the second coil is extended between the first coil and the second coil, and the connecting portion is... The method includes a bending step in which the wide surface of the connecting portion is bent in a direction parallel to the winding shaft, the connecting portion has a first excess portion extending from the end of the first coil as its base, a second excess portion extending from the end of the second coil as its base, and an overhead wire portion connecting the first excess portion and the second excess portion, the molding step involves correcting the twist of the first coil and the second coil while covering at least the connecting coil with resin , and the overhead wire portion is characterized in that, after the bending step is completed, it is the same length as the end-to-end distance, which is the straight-line distance between the end of the first coil and the end of the second coil .

According to the present invention, it becomes easier to correct irregularities and twists in the coils within the connecting coil during the molding of the molded resin, thereby suppressing the generation of burrs.

This is a perspective view of the reactor body. This is a perspective view showing the core section, where (a) shows the core inside the core section and (b) shows the core coating resin outside the core section. This is a first perspective view of the connecting coil. This is a second perspective view of the connecting coil. This is a perspective view showing the state in which the first coil and the second coil are held down by the first plate and the second plate, with (a) showing the side of the first plate and (b) showing the side of the second plate. This shows the state in which the first coil and the second coil are held in place by the first plate and the second plate, and is a cross-sectional view taken along a direction perpendicular to the winding shaft. This is a perspective view showing a reactor with the reactor body covered in molded resin. This is an enlarged side perspective view of the connecting section and the yoke covering section. This is a magnified view of a portion of the first plate.

A reactor and its manufacturing method according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a perspective view showing the configuration of the reactor body 6. The reactor body 6 is used as a boost reactor incorporated into an in-vehicle boost circuit, and is also used as a series reactor, parallel reactor, current-limiting reactor, starting reactor, shunt reactor, neutral point reactor, and arc-extinguishing reactor, among others. This reactor body 6 comprises a molded core 3 and a connecting coil 1.

The molded core 3 is fitted with a connecting coil 1. This molded core 3 is an annular body that acts as a closed magnetic circuit, allowing the magnetic flux generated by the connecting coil 1 to pass through with a permeability higher than that of a vacuum. The molded core 3 includes the core 31 shown in Figure 2(a). The core 31 is a magnetic material such as a ferrite core, laminated steel sheet, compacted magnetic core, or metal composite. A metal composite core is a core formed by mixing and molding magnetic powder and resin.

This core 31 has a ring shape comprising two leg portions 311 to which the connecting coil 1 is attached, and a yoke portion 312 connecting the two leg portions 311. This core 31 is formed by, for example, joining the ends of two U-shaped blocks together. The U-shaped blocks may be joined by bonding their end faces with adhesive or by wrapping them with tape. A gap may be placed within the U-shaped block to increase the magnetic resistance of the core 31.

Furthermore, as shown in Figure 2(b), the molded core 3 is equipped with a core coating resin 32. The core coating resin 32 is a molded product that maintains a certain shape and coats the core 31. The connecting coil 1 is wound around the core 31 via the core coating resin 32. This core coating resin 32 insulates the connecting coil 1, which is fitted into the core 31, from the core 31. The core coating resin 32 is made of materials such as epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephosphate), or a composite thereof.

The core coating resin 32 has an annular shape that follows the shape of the core 31, comprising a leg coating portion 321 that covers the two leg portions 311 and a yoke coating portion 322 that covers the yoke portion 312. The core coating resin 32 covers the core 31 by injection molding the resin into the two U-shaped blocks of the core 31 placed in a mold. The molded core 3 may have an annular shape with two leg portions 311, a θ-shape with three leg portions 311, or even a shape with four or more leg portions 311, consisting of connected annular shapes.

Returning to Figure 1, the connecting coil 1 is a cylindrical winding made of conductive wire 10 such as enamel-coated copper wire. Current flows through it, generating magnetic flux according to the number of turns. To obtain a high inductance value in the high-current region, this connecting coil 1 is formed by arranging multiple coils in parallel, connected so that the direction of the current flowing through each coil is opposite to that of the other. For example, the connecting coil 1 comprises a first coil 11 and a second coil 12. The first coil 11 and the second coil 12 are arranged parallel to each other, along a direction 13B perpendicular to the winding axis 13A. The first coil 11 and the second coil 12 are then fitted into the two legs 311 of the molded core 3 via the leg covering portion 321 of the core covering resin 32.

The first coil 11 and the second coil 12 are connected by a connecting portion 2 extending from one end face, with lead wires 11b and 12b extending from the other end faces for current input and output to the outside. When current flows through the lead wires 11b and 12b to the connected coil 1, the coil 1 generates magnetic flux according to its number of turns. The molded core 3 forms a closed magnetic path, allowing the magnetic flux generated by the connected coil 1 to pass through with a permeability higher than that of a vacuum. Therefore, the reactor body 6 becomes an electromagnetic component that converts electrical energy into magnetic energy, storing and releasing it.

Here, the connecting portion 2 extends between the first coil 11 and the second coil 12 and is bent so as to collapse toward the surface 323 of the yoke covering portion 322 of the core covering resin 32. The detailed configuration of this connecting coil 1 is shown in Figures 3 and 4.

Figures 3 and 4 are perspective views of the connecting coil 1 from various directions. As shown in Figures 3 and 4, the bodies 11a and 12a of the connecting coil 1 are wound bodies formed by spirally winding the conductive wire 10 along the winding shaft 13A, shifting the winding position with each turn. The first coil 11 and the second coil 12 are spiral edgewise coils. The spiral edgewise coil is formed by winding the conductive wire 10 such that the wide surface 26a of the flat rectangular conductive wire 10 expands in the direction perpendicular to the winding shaft 13A, and the narrow surface 26b expands along the winding shaft 13A.

The first coil 11, the second coil 12, and the connecting portion 2 are formed by shaping a single conductive wire 10. The first coil 11 is formed by winding the first winding range 10a of the single conductive wire 10. The second coil 12 is formed by winding the second winding range 10b, which is opposite to the first winding range 10a of the single conductive wire 10. Furthermore, a third connecting range 10c, between the first winding range 10a and the second winding range 10b of the single conductive wire 10, is formed at the connecting portion 2.

The connecting section 2 comprises an excess length 22 extending from the end 11c of the first coil 11 as its base, an excess length 22 extending from the end 12c of the second coil 12 as its base, and an overhead wire section 21 connecting both excess length sections 22. The overhead wire section 21 extends across the first coil 11 and the second coil 12, connecting both excess length sections 22. This overhead wire section 21 has the same length as the end-to-end distance 13C, which is the straight-line distance between the end 11c of the first coil 11 and the end 12c of the second coil 12.

The base end of the excess length 22 extending from the first coil 11 is drawn out in a direction perpendicular to the winding shaft 13A and different from the direction of the end 12c of the second coil 12. The excess length 22 has a bent section 23 in the middle, and from the middle of the excess length 22, the side facing the overhead wire section 21 is bent in the direction of the yoke section 312 (hereinafter referred to as the yoke direction 24), which is opposite to the body 11a of the first coil 11 and the body 12a of the second coil 12. The extended tip of the excess length 22 extending from the first coil 11 is connected to the overhead wire section 21 at a right angle.

Similarly, the base end of the excess length 22 extending from the second coil 12 is drawn out in a direction perpendicular to the winding shaft 13A and different from the direction of the end 11c of the first coil 11. This excess length 22 has a bend 23 in the middle, and from the middle of the excess length 22 toward the overhead wire section 21, it is bent along the winding shaft 13A toward the yoke direction 24, opposite to the body 11a of the first coil 11 and the body 12a of the second coil 12. The extended tip of the excess length 22 extending from the second coil 12 is connected perpendicularly to the overhead wire section 21.

In general, starting from the first coil 11 and following the connecting section 2, the excess length 22 is first pulled out from the end 11c of the first coil 11 in a direction perpendicular to the winding shaft 13A and different from the direction of the end 12c of the second coil 12. The excess length 22 bends at the bending section 23 along the winding shaft 13A towards the yoke 24. The extended tip of the excess length 22 then connects perpendicularly to the end of the overhead wire section 21.

The overhead wire section 21 extends from the body 11a of the first coil 11 and the body 12a of the second coil 12, at a distance along the winding shaft 13A. The overhead wire section 21 extends toward the second coil 12 perpendicular to the winding shaft 13A by the distance between the ends 13C, which is the straight-line distance between the end 11c of the first coil 11 and the end 12c of the second coil 12. The end of the overhead wire section 21 reaches a position where it overlaps with the end 12c of the second coil 12 in the direction of the winding shaft 13A.

The excess length 22 connected to the second coil 12 extends from the end of the overhead wire section 21 along the winding shaft 13A, approaching the body 12a of the second coil 12. This excess length 22 bends at the bending section 23 in a direction perpendicular to the winding shaft 13A, reaching the end 12c of the second coil 12 from a direction different from the direction of the end 11c of the first coil 11.

As shown in Figure 1, such a connecting coil 1 is attached to the molded core 3. In this case, the connecting portion 2 is bent so as to collapse toward the surface 323 of the yoke covering portion 322 of the core covering resin 32. The connecting coil 1 is made by winding a flat rectangular conductive wire 10 using edgewise winding. Therefore, the overhead wire portion 21 of the bent connecting portion 2 has a wide surface 26a that expands parallel to the winding axis 13A, while the narrow surface 26b is perpendicular to the winding axis 13A. That is, when the connecting coil 1 is covered with resin, the narrow surface 26b of the overhead wire portion 21 of the connecting portion 2 aligns with the direction in which the first coil 11 and second coil 12 are pushed to correct any twisting or unevenness in the connecting coil 1. The wide surface 26a of the overhead wire portion 21 expands in a direction perpendicular to the pushing direction.

Figure 5 is a perspective view showing the state in which the first coil 11 and the second coil 12 are held in place by the first plate 41 and the second plate 42, where (a) shows the side of the first plate 41 and (b) shows the side of the second plate 42. As shown in Figure 5, after assembling the connecting coil 1 and the molded core 3, the first coil 11 and the second coil 12 are sandwiched between the first plate 41 and the second plate 42, which are made of an insulating resin. Furthermore, a sensor 5, such as a thermistor, which detects physical quantities such as the temperature of the reactor body 6, is placed in the gap between the first coil 11 and the second coil 12.

The first plate 41 is placed on the upper surface 14a, and the second plate 42 is laid beneath the first coil 11 and the second coil 12 so as to be in contact with the lower surface 14b. The first coil 11 and the second coil 12 have an external shape formed by alternately connecting four curved surfaces and four flat surfaces parallel to the winding shaft 13A. Of the four flat surfaces, the one parallel to the alignment direction 13B of the first coil 11 and the second coil 12 is called the upper surface 14a, and the back surface of this upper surface 14a is called the lower surface 14b.

The first plate 41 is a solid, flat plate with its entire surface filled. The second plate 42, on the other hand, is a frame with an exposed window 42a inside. This second plate 42 allows a portion of the lower surfaces 14b of the first coil 11 and the second coil 12 to be exposed through the window 42a, making it suitable for heat dissipation of the first coil 11 and the second coil 12. Furthermore, the state of the first coil 11 and the second coil 12 can be visually observed through the exposed window 42a of the second plate 42.

As shown in Figure 6, a force is applied to the first coil 11 and the second coil 12 via the first plate 41 in the direction from the upper surface 14a to the lower surface 14b. The first coil 11 and the second coil 12 are pressed against the second plate 42. At this time, the direction of the force applied to the first coil 11 and the second coil 12 is such that the narrow surface 26b of the overhead wire section 21 of the connecting section 2 expands. The direction in which the wide surface 26a of the overhead wire section 21 of the connecting section 2 expands is perpendicular to the direction of this force.

Consequently, the second moment of area of the overhead wire section 21 is proportional to the product of the cube of the width of the narrow surface 26b and the width of the wide surface 26a. In contrast, the second moment of area of the overhead wire section 21 before it is bent at the bending point 23 is proportional to the product of the cube of the width of the wide surface 26a and the width of the narrow surface 26b. That is, in this reactor body 6, the connecting section 2 is bent so that the wide surface 26a of the connecting section 2 tilts in a direction parallel to the winding shaft 13A, making it easier to apply force to the first coil 11 and the second coil 12.

Therefore, it is easier to eliminate the unevenness and twisting of the first coil 11 and the second coil 12. In other words, the first coil 11 and the second coil 12 can be easily pressed against the second plate 42, and the gap between the first coil 11 and the second coil 12 and the second plate 42 can be eliminated.

Furthermore, since the first plate 41 is a solid flat plate, it has higher rigidity than the second plate 42 and is suitable as a pressing plate to eliminate irregularities and twists in the first coil 11 and the second coil 12. This first plate 41 can apply a greater force to the first coil and the second coil 12. In this reactor body 6, the first plate 41 can apply a greater force to the first coil 11 and the second coil 12, and the bending of the connecting portion 2 can transmit a greater force to the first coil 11 and the second coil 12.

As shown in Figure 7, resin is injected into the mold, and the connecting coil 1, including the connecting portion 2, is covered with molded resin 43. When the resin is injected into the mold, the first coil 11 and the second coil 12 are pressed against the second plate 42 by the first plate 41. Therefore, the gap between the second plate 42 and the first and second coils 11 and 12 disappears due to the correction of any irregularities or twists in the first and second coils 11 and 12, and the generation of burrs on the exposed window 42a is suppressed.

Furthermore, the first plate 41, the second plate 42, and the molding resin 43 are made of materials such as epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephosphate), or composites thereof.

Here, Figure 8 is an enlarged side perspective view of the connecting portion 2 and the yoke covering portion 322, with the molded resin 43 removed in the drawing. As shown in Figure 8, the bent portion 23 of the connecting portion 2 is bent at a 90-degree angle, and the overhead wire portion 21 and the surface 323 of the yoke covering portion 322 are parallel. However, the bent portion 23 is positioned at a height distance from the surface 323 of the yoke covering portion 322, and the overhead wire portion 21 and the yoke covering portion 322 have a distance 33D between their opposing surfaces of 0.5 mm to 5.0 mm.

The gap between the overhead wire section 21 and the yoke covering section 322 provides room for the overhead wire section 21 to flex when the first plate 41 presses against the first coil 11 and the second coil 12. However, if the distance between opposing surfaces 33D exceeds 5.0 mm, shrinkage and voids will occur in the molded resin 43 filled between the overhead wire section 21 and the yoke covering section 322. However, if the distance between opposing surfaces 33D is 5.0 mm or less, the occurrence of shrinkage and voids can be suppressed. Therefore, it is possible to prevent the enamel coating from peeling off and the loss of insulation at the exposed shrinkage and void areas of the overhead wire section 21.

Furthermore, if the distance 33D between opposing surfaces exceeds 5.0 mm, there is a risk that the overhead wire section 21 may be buffeted by the resin forcefully entering the gap between the overhead wire section 21 and the yoke covering section 322. However, if the distance 33D between opposing surfaces is 5.0 mm or less, the force that buffets the overhead wire section 21 is weakened, and exposure of the connecting section 2 from the molded resin 43 can be suppressed.

Returning to Figure 7, the molded resin 43 covering the connecting portion 2 has one hole 431a and two holes 431b, exposing the connecting portion 2. These holes 431a and 431b are marks left by an unshown pin used to press down on the connecting portion 2 during the formation of the molded resin 43. Hole 431a is the mark left by pressing down on the overhead wire portion 21, and hole 431b is the mark left by pressing down on the excess length portion 22. Even when a distance 33D between opposing surfaces of 0.5 mm to 5.0 mm is formed, by pressing down on the connecting portion 2, the risk of the resin that has seeped between the overhead wire portion 21 and the yoke covering portion 322 causing the overhead wire portion 21 to be pushed against and the connecting portion 2 being exposed from the molded resin 43 can be further reduced, and damage to the enamel coating of the connecting portion 2 can be further suppressed.

As described above, this reactor is manufactured by including a coil creation process and a molding process. In the coil creation process, a connected coil 1 is created by winding multiple spaced-out points on a single conductive wire 10 using edgewise winding. The connected coil 1 is created in detail as follows: Specifically, a first coil 11 and a second coil 12 adjacent to the first coil 11 are produced. The first coil 11 and the second coil 12 are arranged with their winding axes 13A parallel to each other. A connecting portion 2 connecting the first coil 11 and the second coil 12 is extended between the first coil 11 and the second coil 12.

Furthermore, the coil manufacturing process includes a bending step in which the connecting portion 2 is bent so that its wide surface 26a is parallel to the winding shaft 13A. After the connecting coil 1 is mounted on the core 31, in the subsequent molding step, the twist of the first coil 11 and the second coil 12 is corrected while at least the connecting coil 1 is coated with resin.

As a result, the connecting coil 1 of the reactor body 6 extends between the first coil 11 and the second coil 12, and the connecting portion 2 is bent so that its wide surface 26a is parallel to the winding shaft 13A. This shortens the projected length of the connecting portion 2 along the direction perpendicular to the winding shaft 13A, making it easier to apply force to the first coil 11 and the second coil 12 from that direction. Therefore, it becomes easier to correct any irregularities or twists in the first coil 11 and the second coil 12, and burrs are less likely to occur when molding the molded resin 43.

Furthermore, since the connecting portion 2 is bent so as to tilt in a direction parallel to the winding shaft 13A, the connecting portion 2 does not protrude from the upper surfaces 14a of the first coil 11 and the second coil 12. Therefore, the connecting portion 2 does not interfere with the mold, and the entire upper surfaces 14a of the first coil 11 and the second coil 12 can be pressed by the mold. Consequently, this also makes it easier to apply force to the first coil 11 and the second coil 12.

This connecting section 2 is bent 90 degrees until the wide surface 26a of the overhead wire section 21 is parallel to the winding shaft 13A, and brought closer to the surface 323 of the yoke covering section 322, but is not limited to this. If the projected length of the connecting section 2 along the direction perpendicular to the winding shaft 13A is shortened, it becomes easier to apply force to the first coil 11 and the second coil by the amount of the shortening. However, if the wide surface 26a of the overhead wire section 21 is bent 90 degrees until it is parallel to the winding shaft 13A, the second moment of area is minimized, and the effect of correcting irregularities and twists in the first coil 11 and the second coil 12 is improved. It is preferable to bend it at least 45 degrees or more.

Furthermore, although the connecting portion 2 is bent toward the yoke 24, from the viewpoint of making it easier to apply force to the first coil 11 and the second coil 12, it may also be bent in a direction that overlaps with the body 11a of the first coil 11 and the body 12a of the second coil 12. However, by bending the connecting portion 2 toward the yoke 24, the reactor body 6 can be made lower in the height direction perpendicular to the winding shaft 13A. Also, compared to the case where the connecting portion 2 is bent toward the body 11a or body 12a, the bending jig does not interfere with the sides of the body 11a of the first coil 11 and the body 12a of the second coil 12. Therefore, the position of the bending jig can be freely set, and the accuracy of the bending is improved. In addition, the jig does not scratch or damage the first coil 11 and the second coil 12.

Furthermore, during the bending process of the connecting portion 2, the connecting portion 2 is bent toward the yoke covering portion 322 so as not to contact the surface 323 of the yoke covering portion 322. This prevents the connecting portion 2 from being supported by the yoke covering portion 322 and becoming unable to flex when force is applied to the first coil 11 and the second coil 12 to correct unevenness or twisting.

However, the distance 33D between the opposing surfaces of the connecting portion 2 and the yoke covering portion 322 was set to be between 0.5 mm and 5.0 mm. This reduces the risk of shrinkage or voids occurring in the molded resin 43 filled between the overhead wire portion 21 and the yoke covering portion 322. Therefore, physical contact with the overhead wire portion 21 through shrinkage or voids can be prevented, thus suppressing damage such as peeling of the enamel coating.

Furthermore, the molding resin 43 has multiple holes 431a, 431b through which the wide surface 26a of the connecting portion 2 is exposed. This allows the wide surface 26a of the connecting portion 2 to be held down with a pin during the molding process before being molded with resin. Therefore, even if there is a gap between the overhead wire portion 21 and the yoke covering portion 322 of the connecting portion 2, the risk of the connecting portion 2 being blown around and deformed, and exposed from the molding resin 43, is reduced. Consequently, the connecting portion 2 is protected by the molding resin 43, reducing the risk of damage to, for example, the enamel coating.

Furthermore, the first plate body 41, which acts as a pressing body for the first coil 11 and the second coil 12 in the molding process, is a solid flat plate with its entire surface filled. This first plate body 41 is highly rigid and can strongly press the first coil 11 and the second coil 12. Therefore, correcting irregularities and twists in the first coil 11 and the second coil 12 becomes even easier. If the correction of irregularities and twists is to be facilitated solely by the bending action of the connecting portion 2, the first plate body 41 may be a frame, similar to the second plate body 42.

Furthermore, while the molding process involves pressing the first coil 11 and the second coil 12 through the first plate 41, this is not the only method. The mold may be pressed against the first coil 11 and the second coil 12 to correct any irregularities or twists in the coils; this correction is facilitated by bending the connecting portion 2.

Furthermore, this reactor features a second plate body 42 with an exposed window 42a, illustrating the generation of burrs within the exposed window 42a due to gaps between the first coil 11 and the second coil 12 and the second plate body 42. However, the bending of the connecting portion 2 can address situations where gaps occur at the burr-cutting points on the surfaces of the first coil 11 and the second coil 12.

In this reactor, the connecting section 2 is composed of a wire section 21 and an excess length section 22. This connecting section 2 not only electrically connects the first coil 11 and the second coil 12, but also serves as an offset section to absorb wire feeding errors during the formation of the first coil 11 and the second coil 12. The excess length section 22 is intentionally made longer to absorb wire feeding errors during the formation of the first coil 11 and the second coil 12, and the juxtaposition position of the first coil 11 and the second coil 12 is adjusted using the length of the excess length section 22. In other words, the excess length section 22 is the remaining portion after absorbing wire feeding errors during the formation of the first coil 11 and the second coil 12.

The connecting section 2 is not limited to this; since the excess length 22 is not pre-specified to be longer, it does not function as an offset section and may simply electrically connect the first coil 11 and the second coil 12. That is, the connecting section 2 may include an overhead line section 21 that starts at the end 11c of the first coil 11 and ends at the end 12c of the second coil 12.

Even with a connecting section 2 that merely electrically connects the first coil 11 and the second coil 12, if the wide surface 26a is positioned perpendicular to the winding shaft 13A, it becomes difficult to apply force to correct any unevenness or twisting in the first coil 11 and the second coil 12. On the other hand, even with such a connecting section 2, bending the wide surface 26a of the connecting section 2 so that it tilts parallel to the winding shaft 13A makes it easier to apply force to the first coil 11 and the second coil 12.

Furthermore, the bent portion 23 that folds the connecting portion 2 toward the yoke covering portion 322 is not limited to the excess length portion 22. The connecting portion 2 may be bent along the length of the overhead wire portion 21, or bent at the boundary portion 25 (see Figures 3 and 4) where it bends from the excess length portion 22 to the overhead wire portion 21. However, if the overhead wire portion 21 is bent along its length, the area requiring bending becomes long, and the boundary portion 25 has already been deformed by edgewise bending to extend the overhead wire portion 21 from the end of the excess length portion 22. Therefore, creating the bent portion 23 in the excess length portion 22 is preferable because it allows for easier and more accurate bending.

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. Furthermore, the embodiments and their variations are included within the scope of the present invention.

For example, the first plate 41 functioned as a covering for the first coil 11 and the second coil 12, and as a pressing body for the first coil 11 and the second coil 12. In addition, the first plate 41 can also function as a positioning member for the lead wires 11b and 12b. Figure 9 is a partially enlarged view of the first plate 41 positioned in the second coil 12. The first plate 41 positioned in the first coil 11 has the same shape and function as the first plate 41 positioned in the second coil 12, so its description is omitted.

As shown in Figure 9, the first plate 41 is positioned to overlap each of the leader lines 12b. The first plate 41 has a clamping portion 411 formed at a position overlapping with the leader lines 12b. The clamping portion 411 has a hoe-like shape, which clamps the leader lines 12b and corrects their extensions.

Furthermore, a space 412 is formed at a position overlapping with the lead wire 12b's lead base end 121b. When the lead wire 12b is drawn out from the second coil 12, the lead base end 121b is bent in the direction of drawing. Therefore, the lead base end 121b curves, and a precision error occurs in its size. The space 412 is made large to prevent the first plate body 41 from being unable to be placed or to be unable to be clamped by the clamping portion 411 due to contact with the lead base end 121b with the precision error.

1 Connecting coil 10 Conductive wire 10a First winding range 10b Second winding range 10c Third connecting range 11 First coil 11a Body 11b Lead wire 11c End 12 Second coil 12a Body 12b Lead wire 121b Lead base 12c End 13A Winding shaft 13B Alignment direction 13C Distance between ends 14a Upper surface 14b Lower surface 2 Connecting part 21 Overhead wire part 22 Excess length part 23 Bent part 24 Yoke direction 25 Boundary part 26a Wide surface 26b Narrow surface 3 Molded core 31 Core 311 Leg part 312 Yoke part 32 Core covering resin 321 Leg part covering part 322 Yoke covering part 323 Surface 33D Distance between opposing surfaces 41 First plate body 411 Clamping part 412 Space part 42 Second plate 42a Exposed window 43 Molded resin 431a Hole 431b Hole 5 Sensor 6 Reactor body

Claims (7)

The coil manufacturing process involves creating a connected coil by winding multiple spaced points within a single conductive wire using edgewise winding, and
After attaching the connecting coil to the core, a molding step is performed in which the connecting coil is coated with resin,
Includes,
In the coil fabrication process,
A first coil and a second coil are created within the aforementioned connecting coil.
The first coil and the second coil are arranged with their winding axes parallel to each other.
The connecting portion that connects the first coil and the second coil is extended between the first coil and the second coil,
The process includes bending the connecting portion such that the wider surface of the connecting portion is bent in a direction parallel to the winding shaft,
The connecting portion has a first excess length portion extending from the end of the first coil as its base, a second excess length portion extending from the end of the second coil as its base, and an overhead wire portion connecting the first excess length portion and the second excess length portion.
In the molding process, at least the connecting coil is coated with resin while correcting the twist of the first coil and the second coil.
The overhead wire section, after the bending process is completed, has the same length as the end-to-end distance, which is the straight-line distance between the end of the first coil and the end of the second coil.
A method for manufacturing a reactor characterized by the following. Before attaching the connecting coil to the core, the process includes a core coating step in which a core coating resin, including a yoke coating portion that covers the yoke portion of the ring-shaped core, is applied to the ring-shaped core.
In the bending process, the connecting portion is bent toward the yoke covering portion so as not to come into contact with the surface of the yoke covering portion.
A method for manufacturing a reactor according to claim 1, characterized by the above. The distance between the opposing surfaces of the connecting portion and the yoke covering portion shall be 0.5 mm or more and 5.0 mm or less.
A method for manufacturing a reactor according to claim 2, characterized by the above. In the molding process,
The first coil and the second coil are respectively sandwiched between the first and second plates,
The twist is corrected by pressing the first coil and the second coil through one of the first plate and the second plate.
A method for manufacturing a reactor according to any one of claims 1 to 3, characterized by the above. During the molding process, one of the first plate body and the second plate body that are pressed is a solid plate with its entire surface filled.
A method for manufacturing a reactor according to claim 4, characterized by the above. During the molding process, the other of the first plate and the second plate, against which the first coil and the second coil are pressed, is a frame.
A method for manufacturing a reactor according to claim 4 or 5, characterized by the above. In the molding process, the wide surface of the connecting portion is held in place with a pin before being molded with resin.
A method for manufacturing a reactor according to any one of claims 1 to 6, characterized by the above.