JP7687941B2 - Coil device - Google Patents

Description

The present invention relates to a composite coil device having three or more winding sections.

There is a demand for a composite coil device, such as a composite transformer, that has three or more winding sections and functions as both a transformer and an inductor. A conventional composite coil device has been proposed in which an E-E core is used to form a transformer section, and an E core is added to the back of one of the E cores, resulting in a structure using three E cores, and the winding section placed on the added E core has the function of an inductor (see Patent Document 1, etc.).

However, in conventional coil devices such as those shown in Patent Document 1, the three E-cores are stacked in three stages, making it difficult to shorten the axial length and creating problems in terms of making the device smaller and thinner. In addition, with a structure in which the E-cores are stacked in three stages, the assembly process for the cores and bobbins is complicated.

JP 2012-54549 A

The present invention was made in consideration of these circumstances, and relates to a composite coil device having three or more winding sections, which can be assembled in a simple process and is advantageous for making the device smaller and thinner.

A coil device according to a first aspect of the present invention comprises:
a core having a pair of core base portions extending in a first direction and arranged substantially parallel to each other with a predetermined interval in a second direction perpendicular to the first direction, and core legs protruding from at least one side of the pair of core base portions to the other side, the core legs having a first core leg, a second core leg, a third core leg, a fourth core leg and a fifth core leg arranged at intervals from each other in order along the first direction from one end of the core base portions to the other end in the first direction;
a first winding having a first winding portion that passes through a first gap formed between the first core leg and the second core leg and a third gap formed between the third core leg and the fourth core leg and that is wound so as to surround the second core leg and the third core leg;
a second winding having a second winding portion that passes through a second gap formed between the second core leg and the third core leg and the third gap and is wound so as to surround the third core leg;
a third winding having a third winding portion that passes through a fourth gap formed between the fourth core leg and the fifth core leg and the third gap and is wound so as to surround the fourth core leg;
and a bobbin around which the first winding portion, the second winding portion, and the third winding portion are wound.

In the coil device according to the first aspect of the present invention, a core having first to fifth core legs is used, and the first to third winding parts of the winding are arranged in predetermined positions among the first to fourth gaps, thereby realizing a coil device that can be assembled in a simple process and is advantageous for making the coil device small and low-profile. For example, since all of the first to fifth legs are arranged between one core base part, the coil device can be assembled in a simple process, which is advantageous for making the coil device small and low-profile. In addition, since the first winding part, the second winding part, and the third winding part all pass through the third gap of the core, this is advantageous in terms of making the core small and shortening the winding length.

Also, for example, the second winding and the third winding may be electrically connected.

By electrically connecting the second winding and the third winding, the coil device forms a composite coil device having a third winding as a resonant coil connected in series with the second winding of the transformer portion. However, the electrical connection between the second winding and the third winding may alternatively be made outside the coil device, for example, via a substrate on which the coil device is mounted.

Also, for example, the bobbin may have a first bobbin portion around which the first winding portion is wound, a second bobbin portion around which the second winding portion is wound, and a third bobbin portion around which the third winding portion is wound, and the first bobbin portion, the second bobbin portion, and the third bobbin portion may be separable from one another.

Since the three bobbins are molded separately, the first to third winding parts can be formed separately for each bobbin, and then these can be assembled to manufacture the coil device, making this type of coil device easy to assemble.

Also, for example, the second bobbin portion may have a second hollow cylinder portion through which the third core leg portion is inserted,
The first bobbin portion may have a first hollow cylinder portion through which the second bobbin portion and the second core leg portion are inserted,
The third bobbin portion may have a third hollow cylinder portion through which the fourth core leg portion is inserted.

A coil device having such a bobbin can be easily assembled by arranging the first to third hollow cylinder parts in the corresponding core leg parts. In addition, the bobbin and the first to third winding parts are arranged with good accuracy relative to the core.

Also, for example, the first bobbin portion and the third bobbin portion may be adjacent to each other at the third gap.

In this type of coil device, the transformer portion and the resonant coil portion (inductor portion) are arranged adjacent to each other, which is advantageous in terms of miniaturization.

Also, for example, the distance along the first direction from the one end of the core base portion to the third core leg may be shorter than the distance along the first direction from the other end to the third core leg.

In this type of coil device, the core is asymmetric with respect to the third core leg, and the space required for the transformer section and the space required for the resonant coil section can be allocated without excess or deficiency, which is advantageous in terms of miniaturization.

Also, for example, the third gap may be wider than the second gap in terms of width along the first direction.

Of the first to third winding parts, only the second winding part passes through the second gap, and only the first to third winding parts pass through the third gap. Therefore, by making the third gap wider than the second gap, it is possible to form a gap through which the winding parts can pass without being too large or too small, which is advantageous in terms of miniaturization.

Furthermore, for example, the first core leg and the fifth core leg may be substantially equal in length in a third direction perpendicular to the first direction and the second direction.

This type of core is advantageous in terms of miniaturizing the core, as it is easy to form the first and fifth core legs with the right size to allow magnetic flux to pass through.

Furthermore, for example, with respect to the length in a third direction perpendicular to the first direction and the second direction, the third core leg may be shorter than any of the first core leg, the second core leg, the fourth core leg, and the fifth core leg.

By shortening the length of the third core leg in the third direction, the core base can be made narrow in the center in the first direction. Therefore, in a coil device having such a core, the lead-out portions of the first to third windings can be positioned in the narrowed portion of the core base, which is advantageous in terms of making the coil device smaller and lower-profile.

Furthermore, for example, the first core leg and the fifth core leg may be substantially equal in cross-sectional area in a section perpendicular to the second direction, and the third core leg may be substantially equal to the sum of the first core leg and the fifth core leg.

This type of core is advantageous in terms of miniaturizing the core, as it is easy to form the first core leg, third core leg, and fifth core leg with the right size to allow magnetic flux to pass through.

Also, for example, a second gap may be formed in the second core leg, a third gap may be formed in the third core leg, and a fourth gap may be formed in the fourth core leg, and the length of the third gap in the second direction may be shorter than the lengths of the second gap and the fourth gap in the second direction.

By forming such a gap, a composite coil device that produces a relatively large predetermined leakage can be obtained.

Moreover, a coil device according to a second aspect of the present invention includes a core that extends in a first direction and has a pair of core base portions arranged substantially parallel to each other at a predetermined interval in a second direction perpendicular to the first direction, and a first core leg, a second core leg, a third core leg, a fourth core leg and a fifth core leg that protrude from at least one side of the pair of core base portions to the other side and are arranged at a predetermined interval from each other in order from one end of the core base portions in the first direction to the other end thereof along the first direction, and is separable into a first core portion including at least one of the core base portions and a second core portion including at least the other core base portion;
The bobbin is arranged between one of the core base parts and the other of the core base parts, and has a first bobbin part around which a first winding part of a first winding is wound, a second bobbin part around which a second winding part of a second winding is wound, and a third bobbin part around which a third winding part of a third winding is wound, and the first bobbin part, the second bobbin part and the third bobbin part are separable from each other.

The coil device according to the second aspect of the present invention has a structure in which the first to fifth core leg portions are arranged in a first direction, the core is separable into a first core portion and a second core portion, and the first to third bobbin portions, which are separable from each other, are arranged between two core base portions. Such a coil device can be assembled in a simple process, and is advantageous for making it small and low-profile.

FIG. 1 is an external view of a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil device shown in FIG. FIG. 3 is a perspective view showing a portion of the coil device shown in FIG. 1 excluding the core. FIG. 4 is a top view showing a portion of the coil device shown in FIG. 1 excluding the core. FIG. 5 is a perspective view showing a bobbin in the coil device shown in FIG. FIG. 5 is an exploded perspective view of the bobbin shown in FIG. FIG. 7 is a cross-sectional view of the coil device shown in FIG. FIG. 8 is a conceptual diagram showing a winding structure of the coil device shown in FIG. FIG. 9 is a conceptual diagram showing the flow of magnetic flux in the coil device shown in FIG. FIG. 10 is a conceptual diagram showing a circuit of the coil device shown in FIG.

The present invention will now be described with reference to the embodiments shown in the drawings.

Figure 1 is a schematic perspective view showing a coil device 10 according to one embodiment of the present invention. The coil device 10 can be used, for example, for an in-vehicle power supply, a charging station, an ESS (Energy Storage System), etc., but the uses of the coil device 10 are not limited to these. As shown in Figure 1, the coil device 10 has a core 20, a first winding 31, a second winding 32 (see Figures 7 and 8), a third winding 33, a bobbin 40, etc.

As shown in FIG. 1, the coil device 10 has an outer shape of a substantially rectangular parallelepiped. As shown in FIG. 2, which is an exploded perspective view, the core 20 of the coil device 10 has a pair of plate-shaped core base portions 21a, 21b. The core 20 also has a first core portion 20a having at least a first core base portion 21a, which is one of the pair of core base portions 21a, 21b, and a second core portion 20b having at least a second core base portion 21b, which is the other of the pair of core base portions 21a, 21b, and the first core portion 20a and the second core portion 20b are separable from each other.

In the description of the coil device 10, as shown in Figures 1 and 2, the direction in which the plate-shaped core base parts 21a, 21b extend and in which the core leg parts 22 described later are arranged is defined as the X-axis direction, the direction perpendicular to the pair of plate-shaped core base parts 21a, 21b arranged approximately parallel to each other is defined as the Z-axis direction, and the direction perpendicular to the X-axis direction and the Z-axis direction is defined as the Y-axis direction. In the description of the coil device 10, the Z-axis direction is defined as the up-down direction, but the coil device 10 may be provided so that the first core part 20a is located at the top as shown in Figure 1, or so that the other directions face upward.

As shown in FIG. 2, the core 20 has a pair of core base portions 21a, 21b and a core leg portion 22 disposed between the pair of core base portions 21a, 21b. The first core base portion 21a, which is one of the pair of core base portions 21a, 21b, and the second core base portion 21b, which is the other, both extend in a first direction parallel to the X-axis direction (see FIG. 2 for the first direction D1). The first core base portion 21a and the second core base portion 21b are disposed approximately parallel to each other with a predetermined gap in a second direction perpendicular to the first direction (parallel to the Z-axis direction, see FIG. 2 for the second direction D2).

The core leg 22 protrudes from at least one side of the pair of core base parts 21a, 21b to the other side. As shown in FIG. 2, the core leg 22 in the coil device 10 is composed of a part protruding from the first core base part 21a to the second core base part 21b and a part protruding from the second core base part 21b to the first core base part 21a. That is, the core 20 is an E-E core in which the first core part 20a having the first core base part 21a and a part of the core leg 22 and the second core part 20b having the second core base part 21b and another part of the core leg 22 have approximately the same shape. However, the core 20 of the coil device 10 is not limited to an E-E core, and may have a shape other than an E-E core, such as an E-I core, one of which is composed only of a core base part.

2, the core leg 22 has a first core leg 22a, a second core leg 22b, a third core leg 22c, a fourth core leg 22d, and a fifth core leg 22e. The first core leg 22a, the second core leg 22b, the third core leg 22c, the fourth core leg 22d, and the fifth core leg 22e are arranged in order from one end 21ac, 21bc of the core base parts 21a, 21b to the other end 21ad, 21bd along a first direction parallel to the X-axis direction.

The first core leg 22a, the second core leg 22b, the third core leg 22c, the fourth core leg 22d, and the fifth core leg 22e are arranged at intervals along the first direction. As a result, as shown in FIG. 2, a first gap 24a is formed between the first core leg 22a and the second core leg 22b, a second gap 24b is formed between the second core leg 22b and the third core leg 22c, a third gap 24c is formed between the third core leg 22c and the fourth core leg 22d, and a fourth gap 24d is formed between the fourth core leg 22d and the fifth core leg 22e.

As described below, the lengths in the first direction of the first to fourth gaps 24a, 24b, 24c, and 24d formed between the first to fifth core legs 22a, 22b, 22c, 22d, and 22e are not all the same. However, it is also possible to configure a coil device using a core in which the first to fifth core legs 22a, 22b, 22c, 22d, and 22e are arranged at equal intervals.

Figure 7 is a cross-sectional view of the coil device 10, taken along a cross section parallel to the XZ plane and passing through the center of the coil device 10. As shown in Figure 7, the second core leg 22b has a second gap 22ba, the third core leg 22c has a third gap 22ca, and the fourth core leg 22d has a fourth gap 22da. The length of the third gap 22ca in the second direction (parallel to the Z axis) is shorter than the lengths of the second gap 22ba and the fourth gap 22da in the second direction. This allows the coil device 10 to set the leakage generated in the transformer portion and the resonant coil portion to an appropriate value, and for example, a choke coil connected to the primary side of the coil device 10 (see Figure 10) can be omitted to reduce the size of the entire circuit.

As shown in FIG. 7, the second to fourth gaps 22ba to 22da are air gaps, but the second to fourth gaps 22ba to 22da are not limited to air gaps, and may be formed of a non-magnetic material. Gaps (first and second gaps) may also be formed in the first core leg 22a and the fifth core leg 22e. In this case, it is preferable that the length in the second direction of the gaps formed in the first core leg 22a and the fifth core leg 22e is shorter than that of the second to fourth gaps 22ba to 22da, in terms of the characteristics of the coil device 10 as a composite transformer.

Figure 8 is a conceptual diagram showing the arrangement of the second core portion 20b, the first winding 31, the second winding 32, and the third winding 33 in the coil device 10, and is a view of these components in the coil device 10 from above. Note that the first core portion 20a and the bobbin 40 are omitted from Figure 8.

As shown in Figures 8 and 7, the distance along the first direction (parallel to the X-axis direction) from one end 21ac, 21bc of the core base portions 21a, 21b to the center of the third core leg 22c is shorter than the distance along the first direction from the other end 21ad, 21bd to the center of the third core leg 22c. In other words, the first to fifth core legs 22a to 22e are not arranged at equal intervals in the first direction, and the core 20 is asymmetric with respect to the first direction. By arranging the core legs 22 in the core 20 as shown in Figures 7 and 8, it is possible to form just the right amount of gaps to allow the first to third windings 31, 32, 33 to pass through, thereby making it possible to miniaturize the coil device 10.

As shown in Figs. 2 and 7, a first gap 24a is formed between the first core leg 22a and the second core leg 22b, and the first winding portion 31a of the first winding 31 passes through the first gap 24a. A second gap 24b is formed between the second core leg 22b and the third core leg 22c, and the second winding portion 32a of the second winding 32 passes through the second gap 24b.

A fourth gap 24d is formed between the fourth core leg 22d and the fifth core leg 22e, and the third winding portion 33a of the third winding 33 passes through the fourth gap 24d. A third gap 24c is formed between the third core leg 22c and the fourth core leg 22d, and the first to third winding portions 31a to 33a of the first to third windings 31 to 33 pass through the third gap 24c.

As shown in FIG. 7, the third gap 24c is wider than the second gap 24b in terms of width along the first direction. Also, the third gap 24c is wider than the first gap 24a and the fourth gap 24d in terms of width along the first direction. By making the width of the third gap 24c, through which all of the first to third winding portions 31a to 33a pass, wider than the first gap 24a, the second gap 24b, and the fourth gap 24d, the first to fourth gaps 24a to 24d formed between the core legs 22 can be made to have a width that is just right for the first to third winding portions 31a to 33a that pass through the first to fourth gaps 24a to 24d, which contributes to the miniaturization of the coil device 10.

As shown in FIG. 8, the first core leg 22a (length L1) and the fifth core leg 22e (length L5) are approximately equal in length in a third direction (parallel to the Y-axis direction, see FIG. 8 for the third direction D3) perpendicular to the first and second directions. In addition, the third core leg 22c (length L3) is shorter than the first core leg 22a, the second core leg 22b (length L2), the fourth core leg 22d (length L4), and the fifth core leg 22e in length in the third direction.

By making the lengths of the first to fifth core legs 22a to 22e in the third direction as shown in FIG. 8, as shown in FIG. 2, recesses 21aa and 21ab are formed in the middle of the first core base 22a in the first direction, which are narrower in the third direction than the one end 21ac and the other end 21ad. The first pull-out groove 41b, the second pull-out groove 42b, and the third pull-out groove 43b of the bobbin 40 shown in FIG. 4 can be arranged in these recesses 21aa and 21ab. In this way, by forming the recesses 21aa and 21ab in the first core base 21a and arranging the first to third pull-out grooves 41b to 43b therein, it is possible to suppress the protrusions of the pull-out portions of the first to third windings 31 to 33, and to miniaturize the coil device 10.

As shown in FIG. 8, in terms of the cross-sectional area of a section perpendicular to the second direction (parallel to the Z-axis), the first core leg 22a (cross-sectional area S1) and the fifth core leg 22e (cross-sectional area S5) are approximately equal, and the third core leg 22c (cross-sectional area S3) is approximately equal to the sum of the first core leg 22a and the fifth core leg 22e (cross-sectional area S1+S3). By achieving such a relationship, the magnetic characteristics of the core 20 can be favorably secured. However, each of the core legs 22a to 22e may be different from the embodiment shown in FIG. 8.

Figure 6 is an exploded perspective view of the bobbin 40 included in the coil device 10 shown in Figure 1. As shown in Figure 6, the bobbin 40 has a first bobbin portion 41, a second bobbin portion 42, and a third bobbin portion 43, and the first bobbin portion 41, the second bobbin portion 42, and the third bobbin portion 43 are separable from each other.

As shown in FIG. 2, the first to third bobbin sections 41 to 43 are disposed between the first core base section 21a, which is one of the core base sections, and the second core base section 21b, which is the other of the core base sections. As can be seen from FIG. 3 and FIG. 7, the first winding section 31a of the first winding 31 is wound around the first bobbin section 41. The second winding section 32a (see FIG. 7) of the second winding 32 is wound around the second bobbin section 42. The third winding section 33a of the third winding 33 is wound around the third bobbin section 43.

As shown in FIG. 8, the first to third winding portions 31a to 33a of the first to third windings 31 to 33 of the coil device 10 are arranged between the first core base portion 21a and the second core base portion 21b so as to wrap around at least one of the second and third core legs 22b to 22c.

As shown in Figures 7 and 8, the first winding portion 31a of the first winding 31 passes through the first gap 24a and the third gap 24c of the core 20, and is wound around the second core leg 22b and the third core leg 22c of the core 20.

The second winding portion 32a of the second winding 32 passes through the second gap 24b and the third gap 24c of the core 20, and is wound around the third core leg 22c of the core 20. The third winding portion 33a of the third winding 33 passes through the fourth gap 24d and the third gap 24c of the core 20, and is wound around the fourth core leg 22d.

Figure 3 is a schematic perspective view of the first to third windings 31 to 33 and the bobbin 40 included in the coil device 10, and Figure 4 is a top view of the first to third windings 31 to 33 and the bobbin 40 as viewed from the positive direction of the Z axis. As shown in Figures 2 to 4, the first winding 31 has a pair of first pull-out portions 31b pulled out from the first winding portion 31a. The first pull-out portions 31b, which are both ends of the first winding 31, pass through the first pull-out groove portion 41b of the first bobbin portion 41 and are pulled out to the outside from the first bobbin portion 41.

The second winding 32 also has a pair of second pull-out portions 32b, 32c pulled out from the second winding portion 32a. The second pull-out portion 32b, which is one of the second pull-out portions 32b, 32c that are both ends of the second winding 32, passes through the second pull-out groove portion 42b of the second bobbin portion 42 and is pulled out to the outside from the second bobbin portion 42. The other second pull-out portion 32c, which is the other of the second pull-out portions 32b, 32c, is connected to the third pull-out portion 33c of the third winding 33, as described below.

As shown in FIG. 4, the third winding 33 has a pair of third lead-out portions 33b, 33c that are drawn out from the third winding portion 33a. One of the third lead-out portions 33b passes through the third lead-out groove portion 43b of the third bobbin portion 43 and is drawn out from the third bobbin portion 43 to the outside. The other third lead-out portion 33c of the third winding 33 passes through the third lead-out groove portion 43b of the third bobbin portion 43 and is connected to the other second lead-out portion 32c of the second winding 32. Therefore, the second winding 32 and the third winding 33 are electrically connected via the other second lead-out portion 32c of the second winding 32 and the other third lead-out portion 33c of the third winding 33.

Figure 10 is a conceptual diagram showing the circuit of coil device 10. As shown in Figure 10, in coil device 10, the part including first winding portion 31a and second winding portion 32a forms a transformer portion, and the part including third winding portion 33a forms a resonant coil (secondary resonant coil) portion. Figure 9 is a conceptual diagram showing the flow of magnetic flux (arrow 61) through the transformer portion formed within core 20 of coil device 10 and the flow of magnetic flux (arrow 62) through the resonant coil portion.

As shown in Figure 9, the coil device 10 has more common magnetic paths between the transformer portion and the resonant coil portion than conventional composite coil devices, which is advantageous in terms of miniaturization. In the coil device 10, even if a magnetic path is not formed between the transformer portion and the resonant coil portion, the gap between the first core leg 22a and the fifth core leg 22e is made smaller than the gaps between the other second to fourth core legs 22b to 22d, making it difficult for magnetic fluxes to intersect with each other, preventing problems with mutual interference with each other's operations.

In addition, in the coil device 10, by adjusting the direction of the current as shown in FIG. 10, there are many parts where the magnetic flux flow (arrow 61) through the transformer portion and the magnetic flux flow (arrow 62) through the resonant coil portion are in opposite directions. In particular, in the first core leg 22a and the fifth core leg 22e of the coil device 10, the magnetic flux flow (arrow 61) through the transformer portion and the magnetic flux flow (arrow 62) through the resonant coil portion are in opposite directions. In the coil device 10, by generating magnetic flux in opposite directions, the magnetic flux is cancelled out, and the cross-sectional area of each part of the core 20 can be narrowed.

However, in the coil device 10, the first core leg 22a and the fifth core leg 22e may be configured so that the flow of magnetic flux through the transformer portion (arrow 61) and the flow of magnetic flux through the resonant coil portion (arrow 62) are in the same direction. The cross-sectional area of each part of the core 20 and the direction of the current can be determined taking into account the operating conditions of the coil device 10 and various losses.

As shown in FIG. 6, the second bobbin portion 42 has a second hollow cylinder portion 42a and a pair of second pull-out groove portions 42b. The second winding portion 32a (see FIG. 7) of the second winding 32 is disposed on the outer periphery of the second hollow cylinder portion 42a. The second bobbin portion 42 has an intermediate flange portion 42d and a second guide portion 42e formed near the lower end portion of the second hollow cylinder portion 42a. The intermediate flange portion 42d and the second guide portion 42e guide the second winding portion 32a, which is a single layer winding, and prevent the second winding portion 32a from shifting in the second direction or becoming unwound.

As shown in FIG. 7, the second hollow cylinder 42a has the third core leg 22c inserted therethrough. As shown in FIG. 9, the third core leg 22c, which passes through the second hollow cylinder 42a, functions as the middle leg of the transformer portion of the coil device 10. Also, as shown in FIG. 7, a second cover portion 42c is attached to a portion of the second hollow cylinder 42a disposed in the second gap 24b, which ensures an insulating distance from the second core leg 22b of the second winding portion 32a.

The first bobbin portion 41 shown in FIG. 6 has a first hollow cylinder portion 41a and a pair of second pull-out groove portions 41b. The first winding portion 31a (see FIG. 3 and FIG. 7) of the first winding 31 is arranged on the outer periphery of the first hollow cylinder portion 41a. The first winding portion 31a is wound in two layers, but the number of turns and layers of the first winding portion 31a are not limited to only the embodiment shown in FIG. 7.

As shown in Figures 5 and 7, the first hollow cylinder 41a of the first bobbin portion 41 allows the second bobbin portion 42 and the second core leg portion 22b to pass through. As shown in Figure 7, the third core leg portion 22c, the second hollow cylinder portion 42a, the second winding portion 32a, and at least a portion of the second core leg portion 22b are housed inside the first hollow cylinder portion 41a.

As shown in FIG. 4, the center of the second hollow cylinder 42a housed inside the first hollow cylinder 41a does not coincide with the center of the first hollow cylinder 41a when viewed from the Z-axis direction, and is positioned closer to the third bobbin portion 43 than the center of the first hollow cylinder 41a. As a result, a larger gap is formed between the inner wall of the first hollow cylinder 41a and the outer periphery of the second hollow cylinder 42a on the negative X-axis side, farther from the third bobbin portion 43 than the center of the second hollow cylinder 42a. At least a portion of the second core leg 22b is inserted into the gap formed between the inner wall of the first hollow cylinder 41a and the outer periphery of the second hollow cylinder 42a.

As shown in FIG. 9, the second core leg 22b, which passes through the first hollow cylinder 41a, functions as a leakage adjustment leg for the transformer portion of the coil device 10. Reducing the length of the second gap 22ba of the second core leg 22b increases the leakage of the transformer portion, and increasing the length of the second gap 22ba decreases the leakage. As shown in FIG. 7, a first cover portion 41c is attached to a portion of the first hollow cylinder 41a disposed in the first gap 24a to ensure an insulating distance from the first core leg 22a of the first winding portion 31a.

The third bobbin portion 43 shown in FIG. 6 has a third hollow cylinder portion 43a and a pair of third pull-out groove portions 43b. The third winding portion 33a (see FIG. 3 and FIG. 7) of the third winding 33 is arranged on the outer periphery of the third hollow cylinder portion 43a. The third winding portion 33a is wound in two layers, but the number of turns and layers of the third winding portion 33a is not limited to only the embodiment shown in FIG. 7.

As shown in Figs. 4 and 7, the third hollow cylinder 43a of the third bobbin portion 43 allows the fourth core leg 22d to pass through. As shown in Fig. 9, the fourth core leg 22d, which passes through the third hollow cylinder 43a, functions as the middle leg of the resonant coil portion in the coil device 10. As shown in Fig. 7, a third cover portion 43c is attached to a part of the third hollow cylinder 43a arranged in the fourth gap 24d, which ensures an insulation distance from the fifth core leg 22e of the third winding portion 33a. In addition, a third cover portion 43c is attached to another part of the third hollow cylinder 43a arranged in the third gap 24c, which ensures an insulation distance from the first winding 31 of the third winding portion 33a.

As shown in Figures 4 and 7, the first bobbin portion 41 and the third bobbin portion 43 are arranged adjacent to each other in the third gap 24c of the core 20. As shown in Figure 4, the other of the third pull-out groove portion 43b of the third bobbin portion 43 extends toward the first bobbin portion 41 along the first direction. In addition, the second pull-out groove portion 42b and the third pull-out groove portion 43b are both arranged on the negative Y-axis direction side relative to the first core base portion 21a.

The material of the core 20 of the coil device 10 is not particularly limited, but examples thereof include soft magnetic materials such as ferrite and metal. For example, the first core portion 20a and the second core portion 20b can be produced by forming powder of ferrite, metal, or the like into a predetermined shape. The material of the bobbin 40 is not particularly limited, but examples thereof include insulating resin. For example, the first to third bobbin portions 41 to 43 are produced by molding a material such as resin by injection molding or the like.

In the description of the core 20 and bobbin 40 of the coil device 10, "separable" means that they are assembled from a separate state rather than as a single unit during the assembly process of the coil device 10, and is not limited to those that are not fixed to other members of the coil device 10 by adhesive or the like. Components that are in a "separable" relationship also include those that are assembled from a separate state and are fixed to other members by adhesive or the like during or after assembly.

The first to third windings 31 to 33 of the coil device 10 are not particularly limited, but examples include coated conductor wires having a conductor portion made of copper or the like. The first to third windings 31 to 33 may be solid wires or twisted wires such as Litz wires.

The coil device 10 described above can connect the second winding 32 and the third winding 33 compactly inside the coil device 10. However, unlike the embodiment shown in FIG. 8, the second winding 32 and the third winding 33 may not be connected inside the coil device 10. In this case, the second winding 32 and the third winding 33 can be connected via a substrate on which the coil device 10 is mounted, thereby forming a circuit similar to the circuit shown in FIG. 10.

The coil device 10 can be assembled in a simple process by using a core 20 having the first to fifth core legs 22a to 22e and arranging the first to third winding parts 31a to 33a so that they pass through predetermined positions among the first to fourth gaps 24a to 24d, which is advantageous for making the coil device 10 small and low-profile. That is, since all of the first to fifth core legs 22a to 22e are arranged between the pair of core base parts 21a and 21b, the coil device 10 can be assembled in a simple process and is advantageous for making the coil device 10 small and low-profile. In addition, since all of the first winding part 31a, the second winding part 32a, and the third winding part 33a pass through the third gap 24c of the core 20, this is advantageous in terms of making the core 20 small and shortening the winding length.

In addition, the coil device 10 has a structure in which the first to third bobbin parts 41 to 43, which are separable from each other, are arranged between a pair of core base parts 21a and 21b, so that it can be assembled in a simple process, which is advantageous for making the device smaller and thinner.

The coil device 10 according to the present invention has been described above with reference to an embodiment, but the technical scope of the present invention is not limited to the above-mentioned embodiment, and the present invention naturally includes many other embodiments and variations. For example, the coil device 10 may have a case 50 (see FIG. 8) that houses the core 20 and the bobbin 40, etc., and may have a potting resin that fixes the core 20 and the bobbin 40, etc. to the case 50.

In the coil device 10 shown in the embodiment, as shown in FIG. 10, the second winding portion 32a and the third winding portion 33a are connected in series, the first winding portion 31a constitutes the primary side, and the second winding portion 32a and the third winding portion 33a constitute the secondary side. However, in a coil device in which the first winding portion 31a and the third winding portion 33a are connected in series, the first winding portion 31a and the third winding portion 33a constitute the primary side, and the second winding portion 32a constitutes the secondary side, is also one of the embodiments of the present invention. In such an embodiment, for example, the third lead-out portion 33c shown in FIG. 8 is electrically connected to one of the first lead-out portions 31b.

REFERENCE SIGNS LIST 10...Coil device 20...Core 20a...First core part 20b...Second core part 21...Core base part 21a...First core base part 21ac...One end 21ad...Other end 21aa, 21ab...Recessed part 21b...Second core base part 21bc...One end 21bd...Other end 22...Core leg part 22a...First core leg part 22b...Second core leg part 22ba...Second gap 22c...Third core leg part 22ca...Third gap 22d...Fourth core leg part 22da...Fourth gap 22e...Fifth core leg part 24a...First gap 24b...Second gap 24c...Third gap 24d...Fourth gap D1...First direction D2...Second direction D3...Third direction Reference Signs List 31...First winding 31a...First winding portion 31b...First lead-out portion 32...Second winding 32a...Second winding portion 32b, 32c...Second lead-out portion 33...Third winding 33a...Third winding portion 33b, 33c...Third lead-out portion 40...Bobbin 41...First bobbin portion 41a...First hollow cylinder portion 41b...First lead-out groove portion 41c...First cover portion 42...Second bobbin portion 42a...Second hollow cylinder portion 42b...Second lead-out groove portion 42c...Second cover portion 42d...Intermediate flange portion 42e...Second guide portion 43...Third bobbin portion 43a...Third hollow cylinder portion 43b...Third lead-out groove portion 43c...Third cover portion 50...Case

Claims (12)

a core having a pair of core base portions extending in a first direction and arranged substantially parallel to each other with a predetermined interval in a second direction perpendicular to the first direction, and core legs protruding from at least one side of the pair of core base portions to the other side, the core legs having a first core leg, a second core leg, a third core leg, a fourth core leg and a fifth core leg arranged at intervals from each other in order along the first direction from one end of the core base portions to the other end in the first direction;
a first winding having a first winding portion that passes through a first gap formed between the first core leg and the second core leg and a third gap formed between the third core leg and the fourth core leg and that is wound so as to surround the second core leg and the third core leg;
a second winding having a second winding portion that passes through a second gap formed between the second core leg and the third core leg and the third gap and is wound so as to surround the third core leg;
a third winding having a third winding portion that passes through a fourth gap formed between the fourth core leg and the fifth core leg and the third gap and is wound so as to surround the fourth core leg;
a bobbin around which the first winding portion, the second winding portion, and the third winding portion are wound. The coil device according to claim 1, characterized in that the second winding and the third winding are electrically connected. The coil device according to claim 1 or 2, characterized in that the bobbin has a first bobbin portion around which the first winding portion is wound, a second bobbin portion around which the second winding portion is wound, and a third bobbin portion around which the third winding portion is wound, and the first bobbin portion, the second bobbin portion, and the third bobbin portion are separable from each other. the second bobbin portion has a second hollow cylinder portion through which the third core leg portion is inserted,
the first bobbin portion has a first hollow cylinder portion through which the second bobbin portion and the second core leg portion are inserted,
The coil device according to claim 3 , wherein the third bobbin portion has a third hollow cylinder portion through which the fourth core leg portion is inserted. The coil device according to claim 3 or 4, wherein the first bobbin portion and the third bobbin portion are adjacent to each other at the third gap. A coil device according to any one of claims 1 to 5, wherein the distance along the first direction from the one end of the core base to the third core leg is shorter than the distance along the first direction from the other end to the third core leg. The coil device according to any one of claims 1 to 6, wherein the third gap is wider than the second gap in terms of width along the first direction. The coil device according to any one of claims 1 to 7, wherein the first core leg and the fifth core leg are substantially equal in length in a third direction perpendicular to the first direction and the second direction. A coil device according to any one of claims 1 to 8, characterized in that the third core leg is shorter than any of the first core leg, the second core leg, the fourth core leg and the fifth core leg in terms of length in a third direction perpendicular to the first direction and the second direction. The coil device according to any one of claims 1 to 9, characterized in that the cross-sectional area of the first core leg and the fifth core leg is approximately equal in cross section perpendicular to the second direction, and the cross-sectional area of the third core leg is approximately equal to the sum of the first core leg and the fifth core leg. The coil device according to any one of claims 1 to 10, characterized in that a second gap is formed in the second core leg, a third gap is formed in the third core leg, and a fourth gap is formed in the fourth core leg, and the length of the third gap in the second direction is shorter than the lengths of the second gap and the fourth gap in the second direction. a core having a pair of core base portions extending in a first direction and arranged substantially parallel to each other at a predetermined interval in a second direction perpendicular to the first direction, and a first core leg, a second core leg, a third core leg, a fourth core leg and a fifth core leg protruding from at least one side of the pair of core base portions to the other side and arranged at a predetermined interval from each other in order from one end of the core base portions in the first direction to the other end thereof along the first direction, and separable into a first core portion including at least one of the core base portions and a second core portion including at least the other core base portion;
a first bobbin portion disposed between one of the core base portions and the other of the core base portions, around which a first winding portion of a first winding is wound, a second bobbin portion around which a second winding portion of a second winding is wound, and a third bobbin portion around which a third winding portion of a third winding is wound, wherein the first bobbin portion, the second bobbin portion, and the third bobbin portion are separable from each other.

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