JP7757038B2 - Coil Device - Google Patents

Description

The present invention relates to a coil device that integrates, for example, multiple elements with different functions.

An example of a coil device that integrates elements with multiple different functions is the coil device shown in Patent Document 1 below. Patent Document 1 combines three E-shaped cores to give a single coil device multiple functions.

However, it has been found that such conventional coil devices have a structure that makes it difficult to avoid magnetic saturation.

JP 2012-54549 A

The present invention was made in light of these circumstances, and its purpose is to provide a coil device that makes it easy to integrate multiple elements with different functions while also easily avoiding magnetic saturation.

In order to achieve the above object, a coil device according to the present invention comprises:
A coil device having a first core and a second core,
On the back surface of the base portion on which the outer leg portion of the second core is arranged, a convex portion is formed corresponding to the outer leg portion of the first core, which is connected to the tip surface of the outer leg portion of the first core (the tip surface along the protruding direction; the same applies below).

This configuration makes it possible to give separate and different functions to the first coil element, which includes the first core as a part, and the second coil element, which includes the second core as a part. Furthermore, the second core can also serve as part of the first coil element. This makes it possible to reduce the overall size of a coil device with two or more functions.

In addition, because the protrusions connecting to the tip surfaces of the outer legs of the first core are formed to correspond to the outer legs of the first core, it is possible to position the connection surface between the first and second cores away from the back surface of the second core. As a result, it is easy to position areas where magnetic flux tends to concentrate away from the back surface of the second core, resulting in a structure that is less susceptible to magnetic saturation.

Furthermore, in the coil device of the present invention, polishing only the tip surfaces of the convex portions improves adhesion when connected to the tip surfaces of the outer legs of the first core, improving magnetic coupling. The tip surfaces of the outer legs of the first core may also be polished. In this case, the tip surfaces of the center legs of the first core can be polished at the same time as the tip surfaces of the outer legs of the first core, making it easy to adjust the gap between the tip surfaces of the center legs of the first core and the back surface of the second core.

Preferably, the intersection corner where the convex portion protrudes from the back surface of the base portion of the second core has an R portion or chamfer formed to smoothly connect the inner surface of the convex portion to the back surface of the base portion of the second core. This configuration makes the coil device of the present invention even less susceptible to magnetic saturation.

Preferably, the tip surface of the outer leg portion of the first core and the tip surface of the center leg portion of the first core are positioned on approximately the same plane. This configuration makes it easy to adjust the gap between the tip surface of the center leg portion of the first core and the back surface of the second core simply by adjusting the protruding height of the convex portion formed on the back surface of the second core.

Preferably, the protruding height of the convex portion from the back surface of the second core is smaller than the thickness of the second core. The protruding height of the convex portion from the back surface of the second core is sufficient to form an R portion or chamfered portion at the intersection corner between the convex portion and the back surface. The smaller the protruding height of the convex portion from the back surface of the second core, the easier it is to flatten the tip surface of the convex portion and to improve the magnetic connection with the tip surface of the outer leg of the first core.

Preferably, a gap of a predetermined width is formed between the tip surface of the center leg portion of the first core and the back surface of the base portion of the second core. By forming the gap, it is possible to control the characteristics of the first coil element including the first core.

Preferably, the coil device of the present invention further includes a third core,
The distal end surfaces of the outer legs of the third core are connected to the distal end surfaces of the outer legs of the second core. The second core and the third core can form a second coil element of, for example, a transformer.

Preferably, the length of the third core along its winding axis is different from the length of the first core along its winding axis, and the length of the first core along its winding axis is different from the length of the second core along its winding axis. This configuration makes it possible to realize a coil device having multiple elements with different characteristics.

A gap of a predetermined width may be formed between the center leg portion of the second core and the center leg portion of the third core, or no gap may be formed.

Preferably, a first wire winding is disposed around the middle leg of the first core, and a second wire winding is disposed around the middle leg of the second core. The first wire winding forms part of the first coil element, and the second wire winding forms part of the second coil element.

Preferably, the coil device of the present invention comprises:
a first bobbin that covers the middle leg portion of the first core and around which the first wire is wound;
a second bobbin that covers the middle leg portion of the second core and around which the second wire is wound,
The first bobbin and the second bobbin are fitted together at the side surface of the base portion of the second core.

By placing bobbins between these wires and cores, it is possible to wind the wire around the bobbins before attaching the cores to the bobbins, making it easier to arrange the wire wound around the center leg of each core. It also makes it easier to insulate the wire from the cores. Furthermore, by fitting the first and second bobbins together on the side of the base of the second core, it is easy to integrate these bobbins and to wire the wire leads.

Preferably, the lead portion of the first wire is connected to a first terminal attached to the second bobbin, and the lead portion of the second wire is connected to a second terminal attached to the first bobbin. This configuration makes it easy to attach the lead portions of these wires to terminals while ensuring insulation.

Preferably, the coil device of the present invention has multiple elements with different functions. Elements with multiple functions can be mounted on a single coil device, which requires less material than manufacturing these elements separately, thereby reducing manufacturing costs.

Preferably, the first core functions as part of an inductor, and the second core functions as part of a transformer. Such a coil device can be suitably used, for example, in a charger installed in an automobile.

A coil device according to another aspect of the present invention comprises:
The magnetic coil includes a first core, a second core, and a third core,
On the back surface of the base portion of the second core to which the outer leg portion of the third core is connected, a convex portion that connects to the tip surface of the outer leg portion of the first core is formed in correspondence with the outer leg portion of the first core.

As with the coil device described above, this coil device can be made smaller, and it is easy to integrate elements with multiple different functions, while also realizing a coil device that easily avoids magnetic saturation.

FIG. 1 is an overall perspective view of a coil device according to an embodiment of the present invention. FIG. 2 is a partially exploded perspective view of the coil device shown in FIG. FIG. 3A is an enlarged perspective view of the core portion shown in FIG. 3B is an enlarged perspective view of a core portion according to another embodiment of the coil device shown in FIG. 1. FIG. FIG. 4 is a cross-sectional view of the core portion taken along line IV-IV shown in FIG. 3A. 5A is a cross-sectional view of the coil device shown in FIG. 1 taken along line VA-VA. FIG. 5B is a cross-sectional view of another embodiment of the coil arrangement shown in FIG. 5A. FIG. 5C is a cross-sectional view of yet another embodiment of the coil device shown in FIG. 5A.

The present invention will now be described based on the embodiments shown in the drawings.

1 , a coil device 1 of this embodiment is used, for example, as a coil device for an on-board charger, and is an integrated transformer and inductor. The coil device 1 has a first core 10, a second core 20, a third core 30, a first wire 90, a second wire 92, and a third wire 94.

As shown in FIG. 5A, in this embodiment, the first wire 90 is wound around the first bobbin 40, and the second wire 92 and third wire 94 are each wound around the second bobbin 50. Note that in the drawing, the X-axis direction coincides with the winding axis direction of each of the wires 90, 92, and 93, and the X-axis, Y-axis, and Z-axis are perpendicular to one another. In addition, in this embodiment, the Z-axis coincides with the height direction of the coil device 1.

As shown in FIG. 4, the first core 10, second core 20, and third core 40 each have a cross section that is roughly E-shaped, and are so-called E-shaped cores. The first core 10 and third core 30 are general E-shaped cores, although their lengths in the X-axis direction are different, as shown in the general FIG. 5A. In this embodiment, the second core 20 differs from a general E-shaped core. Details will be described later.

As shown in Figures 2 and 3A, the first core 10 has a rectangular, flat first base 13 parallel to the Y and Z axes. The first core 10 has first outer legs 12 at both ends of the first base 13 in the Y axis direction, and these first outer legs 12 protrude from the inner surface 13b of the base 13 at approximately a right angle along the X axis.

The first core 10 also has a first center leg 11 located approximately midway in the Y-axis direction between the pair of first outer legs 12, protruding from the inner surface 13b of the base 13 along the X-axis in the same direction as the outer legs 12. As shown in FIG. 4 , the first outer leg 12 protrudes from the inner surface 13b of the first base 13 in the X-axis direction by a protruding height H1. In this embodiment, the first center leg 11 protrudes in the X-axis direction by a protruding height H1, similar to the first outer legs 12. As a result, the tip surface 12a of the first outer leg 12 and the tip surface 11a of the first center leg 11 are located on the same plane.

Furthermore, the outer surface 13c located at the upper end of the first base portion 13 along the Z axis is flush with the outer surfaces located at the upper ends of the pair of first outer legs 12 along the Z axis. The height of the first base portion 13 along the Z axis and the height of the first outer legs 12 along the Z axis are approximately the same. The first middle leg 11 has a substantially circular shape in cross section parallel to the Y axis and Z axis, and the outer diameter of the first middle leg 11 is smaller than the height of the first base portion 13 along the Z axis.

As shown in FIG. 2, a predetermined gap is formed between the outer peripheral surface of the first center leg portion 11 and the inner surface 12b of the first outer leg portion 12. One end of the first bobbin 40 in the X-axis direction fits into this predetermined gap. Therefore, the inner surface 12b of the first outer leg portion 12 is curved to correspond to the shape of the first end wall flange 41 of the first bobbin 40. The first center leg portion 11 is cylindrical, and its outer diameter corresponds to the inner diameter of the first through hole 48 of the first bobbin 40.

The second core 20 has a rectangular, flat second base portion 23 that has the same width along the Y and Z axes as the first base portion 13. The thickness along the X axis of the second base portion 23 is preferably approximately the same as or greater than the thickness along the X axis of the first base portion 13, but may be smaller.

The second base portion 23 has second outer legs 22 at both ends in the Y-axis direction, and these second outer legs 22 protrude from the plane of the base portion 23 at approximately right angles along the X-axis. The protruding direction of the second outer legs 22 relative to the second base portion 23 is the same along the X-axis as the protruding direction of the first outer legs 12 relative to the first base portion 13. The second core 20 also has a second middle leg 21 located approximately midway in the Y-axis direction between the pair of second outer legs 22, protruding from the plane of the base portion 23 along the X-axis in the same direction as the outer legs 22.

As shown in FIG. 4 , the second outer leg 22 protrudes in the X-axis direction from the inner surface 23b of the second base portion 23 by a protrusion height H2. The protrusion height H2 may be equal to the protrusion height H1, but is preferably greater than the protrusion height H1. In this embodiment, the second middle leg 21 protrudes in the X-axis direction by a protrusion height H2, similar to the second outer leg 22. As a result, the tip surface 22a of the second outer leg 22 and the tip surface 21a of the second middle leg 21 are located on the same plane, but the protrusion length of the middle leg 21 may be shorter than the protrusion length of the outer leg 22 to provide a gap between the tip surfaces of the middle leg 21.

Also, as shown in Figures 2 and 3A, the outer surface 23c located at the upper end of the second base portion 23 along the Z axis is flush with the outer surfaces located at the upper ends of the pair of second outer legs 22 along the Z axis. The height of the second base portion 23 along the Z axis and the height of the second outer legs 22 along the Z axis are approximately the same. The second middle leg 21 has a substantially circular shape in cross section parallel to the Y axis and Z axis, and the outer diameter of the second middle leg 21 is smaller than the height of the second base portion 23 along the Z axis and is approximately the same as the outer diameter of the first middle leg 11, but may be different.

As shown in FIG. 2, a predetermined gap is formed between the outer peripheral surface of the second center leg portion 21 and the inner surface 22b of the second outer leg portion 22. One end of the second bobbin 50 in the X-axis direction fits into this predetermined gap. Therefore, the inner surface 22b of the second outer leg portion 22 is curved to correspond to the shape of the second end wall flange 51 of the second bobbin 50. The second center leg portion 21 is cylindrical, and its outer diameter corresponds to the inner diameter of the second through hole 58 of the second bobbin 50.

As shown in Figure 4, the back surface 23a of the second base portion 23 faces the tip surface 11a of the first center leg portion 11 of the first core 10 with a predetermined gap between them, and a protrusion 24 is formed on each end of the back surface 23a in the Y-axis direction. Each protrusion 24 protrudes from the back surface 23a of the second base portion 23 to a protrusion height H4 in a direction opposite to the X-axis from the direction in which the second outer leg portion 22 protrudes.

As a result, in this embodiment, a gap W1 corresponding to the protrusion height H4 is formed between the tip surface 11a of the first center leg portion 11 of the first core 10 and approximately the center of the back surface 23a of the second base portion 23. The protrusion height H4 of each protrusion 24 is preferably 1.5 times or less the thickness of the base portion 23 in the X-axis direction, and more preferably less than the thickness of the base portion 23. Furthermore, the protrusion height H4 of each protrusion 24 is preferably 0.1 mm to 5 mm.

At the intersection where the convex portion 24 protrudes from the back surface 23a of the base portion 23 of the second core 20, a rounded or chamfered portion is formed to smoothly connect the inner surface 24b of the convex portion and the back surface 23a of the base portion 23. In this embodiment, the radius of curvature of the rounded portion or the length of the chamfered portion in the X-axis direction corresponds to the protruding height H4 of the convex portion.

As shown in FIG. 2, at least a portion of the inner surface 24b of the convex portion 24 is curved to match the outer shape of the first end wall flange 42 provided at the other end of the first bobbin 40 in the X-axis direction. It is preferable that the tip surfaces 24a, 12a of each convex portion 24 along the X-axis have the same shape so that the tip surfaces 24a, 12a of the outer legs 12 of the first core 10 are abutted and connected.

As shown in FIG. 3A, the third core 30 has a rectangular, flat third base portion 33 that has the same width along the Y and Z axes as the first base portion 13. The thickness along the X axis of the third base portion 33 is preferably approximately the same as the thickness along the X axis of the first base portion 13, but may be different.

The third base portion 33 has third outer legs 32 at both ends in the Y-axis direction, and these third outer legs 32 protrude from the inner surface 33b of the base portion 33 at approximately right angles along the X-axis. The protruding direction of the third outer legs 32 relative to the third base portion 33 is opposite to the X-axis direction of the protruding direction of the second outer legs 22 relative to the second base portion 23. The third core 30 also has a third middle leg 31 located approximately midway in the Y-axis direction between the pair of third outer legs 32, protruding from the inner surface 33b of the base portion 33 along the X-axis in the same direction as the outer legs 32.

As shown in FIG. 4, the third outer leg portion 32 protrudes from the inner surface 33b of the third base portion 33 in the X-axis direction by a protrusion height H3. The protrusion height H3 may be equal to the protrusion height H2, or may be greater or less than the protrusion height H2. In this embodiment, the third middle leg portion 31 protrudes in the X-axis direction by a protrusion height H3, similar to the third outer leg portion 32.

As a result, the tip surface 32a of the third outer leg 32 and the tip surface 31a of the third middle leg 31 are located on the same plane, but the protruding length of the middle leg 31 may be shorter than the protruding length of the outer leg 32 in order to provide a gap in the tip surface 31a of the middle leg 31. In other words, the tip surface 31a of the middle leg 31 may be connected to and in contact with the tip surface 21a of the middle leg 21, or may face each other with a predetermined gap between them.

Furthermore, as shown in Figures 2 and 3A, the outer surface 33c located at the upper end of the third base portion 33 along the Z axis is flush with the outer surfaces located at the upper ends of the pair of third outer legs 32 along the Z axis. The height of the third base portion 33 along the Z axis and the height of the third outer legs 32 along the Z axis are approximately the same. The third middle leg 31 has a substantially circular shape in cross section parallel to the Y axis and Z axis, and it is preferable that the outer diameter of the third middle leg 31 is smaller than the height of the third base portion 33 along the Z axis and approximately the same as the outer diameter of the second middle leg 21.

As shown in FIG. 2, a predetermined gap is formed between the outer peripheral surface of the third center leg portion 31 and the inner surface 32b of the third outer leg portion 32. The other end of the second bobbin 50 in the X-axis direction fits into this predetermined gap. Therefore, the inner surface 32b of the third outer leg portion 32 is curved to correspond to the shape of the second end wall flange 52 of the second bobbin 50. The third center leg portion 31 is cylindrical, and its outer diameter corresponds to the inner diameter of the second through hole 58 of the second bobbin 50.

As shown in FIG. 4, the back surface 33a of the third base portion 33 is preferably a flat surface with no protrusions formed thereon, but may have protrusions similar to the protrusions 24 formed on the back surface 13a of the second core 20. In this embodiment, the back surface 13a of the base portion 13 is also preferably a flat surface with no protrusions formed thereon, but may have protrusions similar to the protrusions 24 formed on the back surface 13a of the second core 20.

As shown in FIG. 2, the first bobbin 40 has a first bobbin body 47, which has a first through hole 48 formed therein. As shown in FIG. 5A, the length of the first bobbin body 47 in the X-axis direction is configured to be longer than the protruding height H1 of the first outer leg 12 shown in FIG. 4 by the amount of the gap W1. The inner diameter of the first through hole 48 shown in FIG. 2 corresponds to the outer diameter of the first center leg 11, and is designed so that the first center leg 11 fits within the first through hole 48.

As shown in FIG. 2, the first bobbin body 47 has first end wall flanges 41, 42 at both ends along the X-axis. A first terminal block 43 extending along the Y-axis is integrally formed on one side (upper end) of one of the first end wall flanges 41 in the Z-axis direction. The length of the first terminal block 43 in the Y-axis direction corresponds to the length of the first base portion 13 in the Y-axis direction. The first terminal block 43 may be fixed to the outer surface 13c of the first base portion 13 with an adhesive or the like.

A first locking plate 44 extending along the Y axis is formed on one side (upper end) of the other first end wall flange 42 in the Z axis direction. An engaging protrusion 45 is formed in the center of the first locking plate 44. The length of the first locking plate 44 in the Y axis direction corresponds to the length of the second base portion 23 in the Y axis direction. The first locking plate 44 may be fixed to the outer surface 23c of the second base portion 23 with an adhesive or the like.

As shown in FIG. 1, the first terminal block 43 is provided with a pair of conductive second terminals 70a, 70b and a pair of conductive third terminals 80a, 80b. These terminals 70a, 70b, 80a, 80b are insert-molded into the terminal block 43, but may also be attached by other methods such as fitting or bonding.

An insulating protrusion 46 is formed between the adjacent second terminal 70b and third terminal 80a to insulate the second lead portion 93b and the third lead portion 95a. The second terminals 70a and 70b have an external connection portion that protrudes in the Z-axis direction and a lead attachment portion that protrudes in the X-axis direction. The lead attachment portion is plate-shaped and has crimping pieces 70a1 and 70b1 that engage the lead portion of the wire. The second terminals 70a and 70b and the third terminals 80a and 80b each have a shape and arrangement that is linearly symmetrical about the X-axis.

As shown in Figure 2, the second bobbin 50 has two second bobbin bodies 57a and 57b connected in the X-axis direction, and a second through-hole 58 that runs through both the second bobbin bodies 57a and 57b in the X-axis direction is formed in each of them.

The total length in the X-axis direction of the second bobbin bodies 57a and 57b shown in FIG. 5A is slightly shorter than the total of the protruding height H2 of the second outer leg portion 22 and the protruding height H3 of the third outer leg portion 32 shown in FIG. 4. The inner diameter of the second through hole 58 shown in FIG. 2 corresponds to the outer diameter of the second center leg portion 21 and the third center leg portion 31, and is determined so that the second center leg portion 11 and the third center leg portion 31 fit within the second through hole 58.

As shown in FIG. 2, an intermediate flange 59 is integrally formed between the second bobbin bodies 57a and 57b, and as shown in FIG. 5A, this improves the insulation of the second wire 92 and the third wire 93 wound around the second bobbin bodies 57a and 57b, respectively. The thickness of the intermediate flange 59 along the X axis may be smaller than the thickness of each end wall flange 13, 23, and 33 along the X axis.

The second bobbin body 57a has a second end wall flange 51 at one end facing the second core 20. The second bobbin body 57b has a second end wall flange 52 at one end facing the third core 30. A second locking plate 54 extending along the Y axis is formed at the upper end of one of the second end wall flanges 52 in the Z axis direction. The length of the second locking plate 54 in the Y axis direction corresponds to the length of the third base portion 33 in the Y axis direction. The second locking plate 54 may be fixed to the outer surface 33c of the third base portion 33 with an adhesive or the like.

A second terminal block 53 extending along the Y axis is formed at the upper end of the other second end wall flange 51 in the Z axis direction. A mating recess 55 is formed in the center underside of the second terminal block 53. The mating recess 55 has a shape and size that corresponds to the mating protrusion 45, allowing the mating protrusion 45 to fit into the mating recess 55. The length of the second terminal block 53 in the Y axis direction corresponds to the length of the second base portion 23 in the Y axis direction. The second terminal block 53 may be fixed to the first locking plate 44 with an adhesive or the like.

As shown in FIG. 1, the second terminal block 53 is provided with a pair of conductive first terminals 60a, 60b. The first terminals 60a, 60b are insert-molded into the second terminal block 53, but may also be separately installed on the second terminal block 53 by fitting or bonding.

The second terminal block 53 may have a lead groove 56a formed in a position corresponding to the X-axis direction of the second terminal 70a, through which the second lead portion 93a is guided. The second terminal block 53 may also have a lead groove 56b formed in a position corresponding to the X-axis direction of the second terminal 70b, through which the second lead portion 93b is guided.

The second terminal block 53 may have a lead groove 56c for guiding the third lead portion 95a formed in a position corresponding to the X-axis direction of the third terminal 80a. The second terminal block 53 may have a lead groove 56d for guiding the third lead portion 95b formed in a position corresponding to the X-axis direction of the second terminal 80b.

The first terminals 60a and 60b are L-shaped metal terminals consisting of an external connection portion protruding in the Z-axis direction and a lead connection portion protruding in the X-axis direction. The terminal mounting portion 53a of the second terminal block 53 to which the first terminal 60a is attached protrudes further toward the first terminal block 43 than the terminal mounting portion 53b to which the first terminal 60b is attached, and the first terminal 60a is positioned closer to the first terminal block 43 than the first terminal 60b.

As shown in FIG. 5A, the first wire 90 is wound around the first bobbin body 47 of the first bobbin 40, forming the wound portion of the first wire and constituting a first coil element (e.g., an inductor). The first lead portion 91a of the first wire 90 is electrically connected to the first terminal 60a. The first lead portion 91b of the first wire 90 is electrically connected to the first terminal 60b. There are no particular limitations on the method of connection, and examples include laser welding, thermocompression bonding, and soldering.

The second wire 92 is wound around the second bobbin body 57a of the second bobbin 50, forming the wound portion of the second wire and constituting part of the second coil element. The second lead portion 93a of the second wire 92 is secured by the crimp piece 70a of the second terminal 70a and is electrically connected to the second terminal 70a. The second lead portion 93b of the second wire 92 is secured by the crimp piece 70b of the second terminal 70b and is electrically connected to the second terminal 70b. These connection methods are the same as those described above.

The third wire 94 is wound around the second bobbin body 57b of the second bobbin 50, forming the wound portion of the third wire and constituting another part of the second coil element. An example of the second coil element is a transformer. The third lead portion 95a of the third wire 94 is secured by the crimp piece 80a of the third terminal 80a and is electrically connected to the third terminal 80a. The third lead portion 95b of the third wire 94 is secured by the crimp piece 80b of the third terminal 80b and is electrically connected to the third terminal 80b. These connection methods are the same as those described above.

In this embodiment, the first core 10, second core 20, and third core 30 are made of a magnetic material such as Ni-Zn ferrite, Mn-Zn ferrite, or a metallic magnetic material. In this embodiment, the first core 10, second core 20, and third core 30 are made by molding and sintering magnetic powder, for example, but they may also be made of a powder compact of magnetic powder and a resin binder.

Furthermore, the first bobbin 40 and the second bobbin 50 are made of plastic, such as PPS, PET, PBT, or LCP, but may also be made of other insulating materials. Furthermore, the first bobbin 40 and the second bobbin 50 are preferably made of the same material, but may also be made of different materials.

The first wire 90, second wire 92, and third wire 94 may each be composed of a solid wire, a stranded wire, or an insulated conductor. Furthermore, these wires 90, 92, and 94 may be round wires or rectangular wires.

Furthermore, these wires 90, 92, and 94 may be made of the same material and structure, or may be different. Furthermore, the material from which these wires 90, 92, and 94 are made may be, for example, copper or copper alloy, or a good conductor such as silver or nickel, but is not particularly limited as long as it is a conductive material. Furthermore, the first terminals 60a and 60b, second terminals 70a and 70b, and third terminals 80a and 80b shown in FIG. 1 are made of a metal such as copper or a copper alloy.

In the coil device 1 according to this embodiment, the first coil element having the first core 10 and first wire 90 shown in FIG. 5A can be used as an inductor. Furthermore, the second coil element having the second core 20 and second wire 92 and the third core 30 and third wire can be used as a transformer.

In other words, the coil device of this embodiment can have coil elements with separate and different functions in a single device. Moreover, the second base portion 23 of the second core 20 can also be used as part of the inductor serving as the first coil element when combined with the first core 10. This makes it possible to reduce the overall size of a coil device having coil elements with two or more functions.

Also, as shown in Figure 4, a protrusion 24 that connects to the tip surface 12a of the outer leg 12 of the first core 10 is formed on the back surface 23a corresponding to the outer leg 12 of the first core 10. This makes it possible to position the connection surface (tip surfaces 12a, 24a) between the first core 10 and the second core 20 away from the back surface 23a of the second core 20. As a result, it becomes easier to position areas where magnetic flux tends to concentrate away from the back surface 23a of the second core 20, resulting in a structure that is less susceptible to magnetic saturation.

Furthermore, in the coil device 1 of this embodiment, polishing only the tip surface 24a of the convex portion 24 improves adhesion when connected to the tip surface 12a of the outer leg portion 12 of the first core 10, thereby improving magnetic coupling. The tip surface 12a of the outer leg portion 12 of the first core 10 may also be polished. In this case, the tip surface 11a of the center leg portion 11 of the first core 10 can be polished simultaneously with the polishing of the tip surface 12a of the outer leg portion 12 of the first core 10, making it easy to adjust the gap W1 between the tip surface 11a of the center leg portion 11 of the first core 10 and the back surface 23a of the second core 20.

In addition, at the intersection corner where the convex portion 24 protrudes from the back surface of the base portion 23 of the second core 20, an R portion or chamfer is formed to smoothly connect the inner surface 24b of the convex portion 24 and the back surface 23a of the base portion 23 of the second core 20. With this configuration, the coil device 1 of this embodiment is even less susceptible to magnetic saturation.

In addition, in this embodiment, the tip surface 12a of the outer leg portion 12 of the first core 10 and the tip surface 11a of the middle leg portion 11 of the first core 10 are located on approximately the same plane. This configuration makes it easy to adjust the gap W1 between the tip surface 11a of the middle leg portion 11 of the first core 10 and the back surface 23a of the second core 20 simply by adjusting the protrusion height H4 of the convex portion 24 formed on the back surface 23a of the second core 20.

In addition, the tip surface 12a of the first outer leg portion 12 and the tip surface 11a of the first center leg portion 11 can be polished simultaneously, simplifying the manufacturing process. This makes it possible to reduce the manufacturing costs of the coil device 1.

The protruding height H4 of the convex portion 24 from the back surface 23a of the second core 20 is smaller than the thickness of the base portion 23 of the second core 20 along the X-axis. The protruding height H4 of the convex portion 24 from the back surface 23a of the second core 20 is sufficient to form an R portion or chamfered portion at the intersection corner between the convex portion 24 and the back surface 23a.

The smaller the protrusion height H4 of the convex portion 24 from the back surface 23a of the second core 20, the easier it is to flatten the tip surface 24a of the convex portion 24 and to improve the magnetic connection with the tip surface 12a of the outer leg portion 12 of the first core 10. The tip surface 24a of the convex portion 24 of the second core 20 only needs to be in contact with and connected to the tip surface 12a of the outer leg portion 12 of the first core 10; it does not necessarily have to be joined with an adhesive, but bonding is also acceptable.

A gap W1 of a predetermined width is formed between the tip surface 12a of the center leg portion 12 of the first core 10 and the back surface 23a of the base portion 23 of the second core 20. By forming the gap W1, it is possible to control the coil characteristics of the inductor including the first core 10.

The coil device 1 of this embodiment further includes a third core 30, with the tip surface 32a of the outer leg 32 of the third core 30 connected to the tip surface 22a of the outer leg 22 of the second core 20. The second core 20 and the third core 30 can form a second coil element, such as a transformer. Note that the tip surface 22a of the outer leg 22 of the second core 20 only needs to be in contact with and connected to the tip surface 32a of the outer leg 32 of the third core 30; they do not necessarily need to be joined with an adhesive, but may be bonded.

The length H3 along the X-axis (winding axis) of the third core 30 shown in Figure 4 is different from the length along the X-axis of the first core 10, which in turn is different from the length along the X-axis of the second core 20. By configuring it in this way, it is possible to realize a coil device 1 having multiple coil elements with various different characteristics.

In this embodiment, as shown in FIG. 5A, a winding portion of the first wire 90 is arranged around the middle leg 11 of the first core 10, and a winding portion of the second wire 92 is arranged around the middle leg 21 of the second core 20. The winding portion of the first wire 90 forms part of the inductor as the first coil element, and the winding portion of the second wire 92 forms part of the transformer as the second coil element.

As shown in FIG. 5A, the coil device 1 of this embodiment includes a first bobbin 40 that covers the middle leg portion 11 of the first core 10 and around which the first wire 90 is wound. The coil device 1 also includes a second bobbin 50 that covers the middle leg portion 21 of the second core 20 and has a second bobbin body 57a around which the second wire 92 is wound.

The second bobbin 50 also has a second bobbin body 57b insulated in the X-axis direction by a second bobbin body 57a and an intermediate flange 69. The second bobbin body 57b covers the middle leg portion 31 of the third core 30, and the third wire 94 is wound around it. The first bobbin 40 and the second bobbin 50 are fitted and connected on the outer surface 23c of the base portion 23 of the second core 20.

By interposing the bobbins 40, 50 between these wires 90, 92, 94 and the cores 10, 20, 30, it is possible to wind the wires 90, 92, 94 around the bobbins 40, 50 and then attach each core 10, 20, 30 to the bobbins 40, 50. It also makes it easier to arrange the wound portions of each wire 90, 92, 94 around the middle legs 11, 21, 31 of each core 10, 20, 30.

It also facilitates insulation between the wires 90, 92, and 94 and the cores 10, 20, and 30. Furthermore, by fitting the first bobbin 40 and the second bobbin 50 together at the outer surface 23c of the base portion 23 of the second core 20, it is easy to integrate these bobbins 40 and 50, and as shown in Figure 1, it also facilitates wiring of the lead portions 91a, 91b, 93a, 93b, 95a, and 95b of the wires 90, 92, and 94.

The lead portions 91a and 91b of the first wire 90 are connected to the first terminals 60a and 60b attached to the second bobbin 50, and the lead portions 93a and 93b of the second wire 92 are connected to the second terminals 70a and 70b attached to the first bobbin 40. The lead portions 95a and 95b of the third wire 94 are connected to the second terminals 80a and 80b attached to the first bobbin 40. This configuration makes it easy to attach the lead portions 91a, 91b, 93a, 93b, 95a, and 95b of these wires 90, 92, and 94 to terminals while ensuring insulation.

Furthermore, the coil device 1 of this embodiment has multiple elements with different functions, allowing elements with multiple functions to be mounted on a single coil device, which requires less material than manufacturing these elements separately and reduces manufacturing costs.

In addition, in this embodiment, the first core 10 functions as part of an inductor, and the second core 20 and the third core 30 function as part of a transformer. Such a coil device 1 can be suitably used, for example, in a charger installed in an automobile.

5B, the coil device 1 according to this embodiment is similar to the first embodiment except for the structure of the second bobbin 50 and the arrangement of the second wire 92 and the third wire 94. In the following description, descriptions of parts common to the first embodiment will be omitted.

In this embodiment, the second bobbin 50 has a single second bobbin body 157 and does not have an intermediate flange. The second wire 92 is wound on the lower side of the second bobbin body 157, and the third wire 94 is wound on the upper side above the second wire 92. Each wire 92, 94 is made of an insulating coated wire and is insulated. Alternatively, insulating tape or the like may be wound between the wires 92, 94.

In any case, in this embodiment, the coupling between the second coil element portion formed by the second wire 92 and the third coil element portion formed by the third wire 94 is stronger than in the first embodiment.

5C, the coil device 1 according to this embodiment is similar to the first embodiment except that the second bobbin 50 has a different structure and the second wire 92 and the third wire 94 are wound around the second bobbin body in different positions. In the following description, descriptions of parts common to the first embodiment will be omitted.

In this embodiment, the second bobbin 50 has multiple intermediate flanges 259a-259g that divide it into multiple (e.g., eight) second bobbin bodies 257a-257h. The second bobbin bodies 257a-257h are arranged around the outer periphery of the bobbin 50 along the X-axis in this order, starting from the side closest to the first core 10. A second wire 92 and a third wire 94 are wound alternately around each of the second bobbin bodies 257a-257h.

In this embodiment, the coupling between the second coil element portion formed by the second wire 92 and the third coil element portion formed by the third wire 94 is stronger than in the first embodiment.

Note that the present invention is not limited to the above-described embodiments and can be modified in various ways within the scope of the present invention.

For example, in the above-described embodiment, the second core 20 is a so-called E-shaped core, but is not limited to this and may be a flat core having only a base portion 23. For example, instead of the outer leg portions 22, a convex portion similar to the convex portion 24 formed on the back surface 23a may be formed on the inner surface 23b of the base portion 23, at a position symmetrical with respect to the base portion 23.

Even in this case, as in the previously described embodiment, a convex portion 24 that connects to the tip surface of the outer leg 12 of the first core 10 is formed on the back surface of the base portion 23 of the second core 20, to which the outer leg 32 of the third core 30 is connected, in correspondence with the outer leg 12 of the first core 10.

3B, the coil device according to this embodiment is similar to the coil device according to the first embodiment except that the structures of the first core 110, the second core 120, and the third core 130 are different from those of the first embodiment. In the following explanation, explanations of parts common to the first embodiment will be omitted.

In the first embodiment, the first core 10, second core 20, and third core 30 are formed using a mold that is divided along the X axis (vertical extrusion molding), whereas in this embodiment, the first core 110, second core 120, and third core 130 are formed using a mold that is divided along the Z axis (horizontal extrusion molding).

In other words, in this embodiment, the first outer leg 12 of the first core 110 has inner surfaces 12b that are parallel to the Z axis, and both sides of the first center leg 11 along the Y axis have flat surfaces 11b that are parallel to the Z axis. Therefore, the first core 110 has a simple structure with no curved surfaces in the X-Z plane.

Furthermore, in this embodiment, the second outer leg 22 of the second core 120 has an inner surface 22b that is parallel to the Z axis, the convex portion 24 has an inner surface 24b that is parallel to the Z axis, and both sides of the second center leg 21 along the Y axis have flat surfaces 21b that are parallel to the Z axis. Therefore, the second core 120 has a simple structure with no curved surfaces in the X-Z plane.

Furthermore, in this embodiment, the third outer leg 32 of the third core 130 has an inner surface 32b that is parallel to the Z axis, and both sides of the third center leg 31 along the Y axis have flat surfaces 31b that are parallel to the Z axis. Therefore, the first core 130 has a simple structure with no curved surfaces in the X-Z plane.

As described above, in this embodiment, the first core 110, second core 120, and third core 130 can each be molded using a mold that is divided along the Z axis (lateral push molding).

In addition to applications other than as a coil device integrating a transformer and inductor for an on-board charger, the coil device of the present invention can also be used as a coil device for all applications using resonant circuits, such as resonant transformers for home appliances, AV equipment, and communication power supplies.

DESCRIPTION OF SYMBOLS 1... Coil device 10, 110... First core 11... First center leg portion 11a... Tip surface 11b... Flat surface 12... First outer leg portion 12a... Tip surface 12b... Inner surface 12c... Outer surface 13... First base portion 13a... Back surface 13b... Inner surface 13c... Outer surface 20, 120... Second core 21... Second center leg portion 21a... Tip surface 21b... Flat surface 22... Second outer leg portion 22a... Tip surface 22b... Inner surface 22c... Outer surface 23... Second base portion 23a... Back surface 23b... Inner surface 23c... Outer surface 24... Convex portion 24a... Tip surface 24b... Inner surface 30, 130... Third core 31... Third center leg portion 31a... Tip surface 31b... Flat surface 32...Third outer leg portion 32a...Tip surface 32b...Inner surface 32c...Outer surface 33...Third base portion 33a...Rear surface 33b...Inner surface 33c...Outer surface 40...First bobbin 41, 42...First end wall flange 43...First terminal block 44...First locking plate 45...Fitting protrusion 46...Insulating protrusion 47...First bobbin body 48...First through hole 50...Second bobbin 51, 52...Second end wall flange 53...Second terminal block 53a, 53b Terminal mounting portion 54...Second locking plate 55...Fitting recess 56a, 56b, 56c, 56d...Lead groove 57a, 57b, 157, 257a to 257h...Second bobbin body 58...Second through hole 59, 259a to 259g... Intermediate flanges 60a, 60b... First terminals 70a, 70b... Second terminals 70a1, 70b1... Crimping pieces 80a, 80b... Third terminals 80a1, 80b1... Crimping pieces 90... First wire 91a, 91b... First lead portion 92... Second wire 93a, 93b... Second lead portion 94... Third wire 95a, 95b... Third lead portion

Claims (13)

A coil device having a first core, a second core, and a first bobbin,
a pair of protrusions connected to the tip surfaces of the pair of outer legs of the first core are formed on both widthwise ends of the back surface of the base portion on which the center leg and outer leg portions of the second core are arranged, corresponding to the pair of outer legs of the first core; and the center leg of the first core faces a flat surface between the pair of protrusions on the back surface of the base portion, forming a facing gap;
the first bobbin has a first end wall collar;
the first end wall flange is located between a pair of the protrusions formed on the back surface of the second core,
an upper portion of the first end wall flange projects above an upper end of the second core from between the pair of protrusions,
A coil device in which a first locking plate formed on an upper portion of the first end wall flange is bent relative to the first end wall flange in the direction of the center leg portion of the second core. The coil device described in claim 1, wherein the intersection corner where the convex portion protrudes from the back surface of the base portion of the second core has a rounded or chamfered portion that smoothly connects the inner surface of the convex portion to the back surface of the base portion of the second core. A coil device as described in claim 1 or 2, wherein the tip surface of the outer leg portion of the first core and the tip surface of the middle leg portion of the first core are positioned on approximately the same plane. A coil device according to any one of claims 1 to 3, wherein the protruding height of the convex portion from the back surface of the second core is smaller than the thickness of the base portion of the second core. A coil device according to any one of claims 1 to 4, wherein a gap of a predetermined width is formed between the tip surface of the center leg of the first core and the back surface of the base of the second core. Further having a third core,
6. The coil device according to claim 1, wherein a tip end surface of an outer leg portion of the third core is connected to a tip end surface of an outer leg portion of the second core. The length of the third core along the winding axis is different from the length of the first core along the winding axis,
The coil device according to claim 6 , wherein the length of the first core along the winding axis is different from the length of the second core along the winding axis. A coil device as described in claim 6 or 7, wherein a gap of a predetermined width is formed between the center leg portion of the second core and the center leg portion of the third core. a winding of a first wire is disposed around the middle leg of the first core;
9. The coil device according to claim 1, wherein a second wire is wound around the middle leg of the second core. a first bobbin that covers the middle leg portion of the first core and around which the first wire is wound;
a second bobbin that covers the middle leg portion of the second core and around which the second wire is wound,
The coil device according to claim 9 , wherein the first bobbin and the second bobbin are fitted together at an upper end of a base portion of the second core. a lead portion of the first wire connected to a first terminal attached to the second bobbin;
11. The coil device according to claim 10, wherein a lead portion of the second wire is connected to a second terminal attached to the first bobbin. 12. The coil device according to claim 1, comprising a plurality of elements with different functions. The coil device according to claim 12 , wherein the first core functions as a part of an inductor, and the second core functions as a part of a transformer.