JP6743680B2 - Coil device - Google Patents

Description

The present invention relates to a coil device that can be suitably used as a transformer such as a leakage transformer.

Coil devices are used in various electric appliances and for various purposes. For example, a coil device is used in an on-vehicle charger for an EV (Electric Vehicle), a PHV (Plug-in Hybrid Vehicle) or a commuter (vehicle), an LLC circuit, etc. It is commonly used as a transformer such as a transformer.

As a coil device, for example, a coil device disclosed in Patent Document 1 shown below is known. In the coil device disclosed in Patent Document 1, it is easy to adjust the leakage characteristics, and it is possible to cope with higher frequencies while increasing the current.

In the conventional coil device disclosed in Patent Document 1 and the like, a pair of lead portions corresponding to both ends of a wire forming the coil are close to each other at a position close to the coil, and when the lead portion is pulled away from the coil, It is common to connect the terminals so that they are separated from each other. However, it has been found that the leakage characteristic is not stable in such a general lead-out structure of the lead portion. Particularly in recent years, as the voltage applied to the coil device has become higher in frequency, there has been a problem in stabilizing leakage characteristics in a high frequency band.

JP, 2013-254890, A

The present invention has been made in view of such circumstances, and an object thereof is to provide a coil device having stable leakage characteristics.

In order to achieve the above object, the coil device according to the present invention,
A coil device having a bobbin and a coil mounted on the outer periphery of the bobbin,
The pair of first lead portions that are drawn from the coil and that are formed by both ends of the first wire,
A pair of first rising portions extending in the winding axis direction of the coil,
A pair of first drawer main body portions extending in a direction away from the coil while maintaining a distance smaller than a distance between the pair of first rising portions;
A pair of first direction changes that connect the first rising portion and the first drawer body portion and change the direction of the first rising portion toward the direction of the first drawer body portion. Department,
It is characterized by having.

In the coil device according to the present invention, the pair of first lead portions are pulled out from the coil along the winding axis at the first rising portion, and then the first direction changing portion causes a gap between the pair of first lead portions. It is bent in a narrowing direction and then moved away from the coil at the first drawer body. That is, in the coil device according to the present invention, the gap distance between the pair of first drawer main body portions is smaller than the gap distance between the pair of first rising portions. Therefore, the pair of first lead portions are pulled out from the coil in a separated state and come close to each other after standing up along the winding axis. The inventors of the present invention have found that such a lead-out structure makes it possible to realize a coil device having stable leakage characteristics as compared with a conventional coil device.

Experiments by the present inventors have revealed that the leakage characteristic changes depending on the distance between the pair of drawer body portions. Therefore, the leakage characteristic can be optimized by adjusting the interval between the pair of drawer main body portions so that the leakage characteristic becomes good.

Preferably, a first terminal block is formed on the bobbin, and the first lead part raised at the first rising portion is provided on the first terminal block of the first direction changing part. At the position, a pair of first locking portions are formed which are wound from the outside to the inside and are guided in the direction of the first drawer main body portion. With this configuration, each first lead portion is locked to the locking portion without slack, and the unwinding of the coil portion formed by the first wire continuously wound around the bobbin on the first lead portion. The sushi is prevented.

Preferably, the first terminal block includes a pair of the first lead portions located between the pair of first locking portions and extending from the first direction changing portion to the first drawer main body portion. Separation convex portions for guiding and forming a predetermined gap between the pair of first drawer main body portions are formed. Due to the presence of the separation protrusions, the pair of first lead portions are fixed by being sandwiched between the separation protrusions and the first locking portions, and the pair of first lead-out main body portions are separated from the coil by a small gap distance. It becomes easy to pull out in the direction.

Preferably, the coil device further includes a pair of second lead portions that are formed at both ends of a second wire different from the first wire and that are drawn out from the coil.

The pair of second lead portions includes
A pair of second rising parts extending in the winding axis direction of the coil;
A pair of second drawer main body portions extending in a direction away from the coil while maintaining a distance wider than a distance between the pair of second rising portions;
A pair of second direction changes that connect the second rising portion and the second drawer main body portion and change the direction of the second rising portion toward the direction of the second drawer main body portion. And a part.

Similarly to the pair of first lead portions, the pair of second lead portions may extend as the second lead-out main body portion in the direction away from the coil while maintaining a distance smaller than the distance between the second rising portions. However, if the voltage applied to the second lead portion is high, the opposite may be done. That is, the pair of second lead portions may extend as the second lead-out main body portion in a direction away from the coil while keeping a distance wider than the distance between the second rising portions.

Preferably, the bobbin has a second terminal block formed thereon, and the second terminal block has the second lead portion raised at the second rising portion and the second direction changing portion. A pair of second locking portions are formed which are wound from the inner side to the outer side at positions and are guided toward the second drawer main body portion. With this configuration, each second lead portion is locked to the locking portion without slack, and the unwinding of the coil portion formed by the second wire continuous to the second lead portion is prevented.

Preferably, the rising direction of the first rising portion and the rising direction of the second rising portion are the same direction, and the second terminal block is different from the first terminal block formed on the bobbin. And located on the same side of the winding axis of the coil. With this configuration, it becomes easy to locate the bottom surface of the bobbin located on the opposite side of the first terminal block and the second terminal block along the winding axis on the cooling side, and to cool the coil and the bobbin. Efficiency is improved.

Preferably, in order to ensure insulation between a portion where the second wire forming a part of the coil is wound around the bobbin and the first rising portion, the inside of the first rising portion is secured. An insulating cover is attached to the outer circumference of the bobbin. With this configuration, for example, good insulation can be maintained between the coil portion formed of the first wire and the coil portion formed of the second wire.

Preferably, the coil includes a first coil part, a second coil part, and an intermediate coil part located between the first coil part and the second coil part along a winding axis of the coil. Have
The intermediate coil portion is composed of the first wire,
The first coil portion and the second coil portion are composed of the second wire for continuously forming the first coil portion and the second coil portion.

By having the structure in which the intermediate coil portion is sandwiched between the first coil portion and the second coil portion, the coupling between these coil portions can be increased, and the leakage characteristics can be easily stabilized. Further, stable leakage characteristics can be obtained even in the high frequency band.

The first wire may constitute either a primary coil or a secondary coil, and the second wire may constitute either the primary coil or the secondary coil.

Preferably, the number of turns of the first wire wound around the bobbin is smaller than the number of turns of the second wire wound around the bobbin. When the pair of first lead portions located at both ends of the first wire having a small number of turns has the configuration of the present invention, the function and effect of the present invention are enhanced.

FIG. 1 is a perspective view of a transformer as a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the transformer shown in FIG. FIG. 3 is a perspective view when the case is removed from the transformer shown in FIG. FIG. 4 is a perspective view when the core is removed from the transformer shown in FIG. FIG. 5 is a cross-sectional view of essential parts of the transformer taken along the line VV shown in FIG. FIG. 6A is a cross-sectional view of essential parts of the transformer taken along the line VI-VI shown in FIG. 1. FIG. 6B is a sectional view of the main part of the bobbin taken along the line VI-VI shown in FIG. 1. FIG. 7A is a perspective view of a bobbin and the like in the transformer shown in FIG. 7B is a perspective view of the bobbin shown in FIG. 7A when viewed from another angle. FIG. 7C is a perspective view of the insulating cover and the like shown in FIG. 6A. FIG. 7D is a perspective view of another insulating cover shown in FIG. 6A. 8A is a perspective view showing an example of a common wire and an intermediate wire wound around the bobbin shown in FIG. 7A. 8B is a perspective view showing a positional relationship between the common wire and the intermediate wire shown in FIG. 8A and the insulating cover shown in FIGS. 7C and 7D. FIG. 8C is a perspective view of the common wire and the like shown in FIG. 8B when viewed from another angle. FIG. 9 is a side view of the common wire and the intermediate wire shown in FIG. 8A. FIG. 10 is an exploded perspective view of the common wire and the intermediate wire shown in FIG. 8A. FIG. 11 is a circuit diagram showing an equivalent circuit of the transformer shown in FIG.

Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

A transformer 10 as a coil device according to the present embodiment shown in FIG. 1 is mounted on, for example, an EV (Electric Vehicle), a PHV (Plug-in Hybrid Vehicle), or a vehicle for a commuter (vehicle). For example, it is used for a battery charger, and is used for forming a part of an LLC circuit.

As shown in FIG. 2, the transformer 10 includes a bobbin 20, magnetic cores 40a and 40b, a cover 50, a drawing wire cover 60, a pedestal 70, a case 90 for accommodating them therein, and a bottom plate 92. Have. In the drawings, the X axis, the Y axis, and the Z axis are perpendicular to each other, and the Z axis corresponds to the height (thickness) of the transformer 10. In the present embodiment, the lower side of the transformer 10 in the Z-axis direction is the transformer installation surface. Moreover, the Y-axis is aligned with the longitudinal direction of the base portions 44a and 44b of the magnetic cores 40a and 40b. Furthermore, the X-axis is aligned with the longitudinal direction of the bobbin 20.

In the present embodiment, the bottom plate 92 is attached to the bottom opening of the case 90 by means such as caulking or bonding to form the case 90 whose top is open. The bottom plate 92 is preferably made of a metal such as aluminum copper and iron having excellent heat dissipation, but may be made of PPS, PET, PBT or the like. Since the lower end surface of the magnetic core 40, which will be described later, in the Z-axis direction comes into contact with the bottom plate 92, the bottom plate 92 is preferably made of a material having excellent heat dissipation. A cooling device such as a cooling pipe or a cooling fin may be mounted below the case 90 via a bottom plate 92 or directly.

Boss portions 91 are formed in the four corners of the case 90 near the middle portion in the Z-axis direction. Bolt holes are formed in the boss portion 91, for example. The case 90 itself is made of metal, but may be made of synthetic resin or the like. The bottom plate 92 and the case 90 may be integrally formed by die casting of aluminum or the like. The heat dissipation is further enhanced by forming the entire case with metal.

The inside of the case 90 may be filled with a heat dissipation resin. The heat-dissipating resin is not particularly limited, but a resin having excellent heat dissipation, for example, having a thermal conductivity of 0.5 to 5, preferably 1 to 3 W/m·K, is preferable. Examples of the resin having excellent heat dissipation include silicone-based resin, urethane-based resin, and epoxy-based resin, and among them, silicone resin and urethane resin are preferable. Further, in order to enhance heat dissipation, the resin may be filled with a filler having high thermal conductivity.

Further, the heat dissipation resin of this embodiment has a Shore A hardness of 100 or less, preferably 60 or less. This is because even if the magnetic cores 40a and 40b and the bobbin 20 are deformed by heat, the deformation is absorbed and an excessive stress is not generated in the magnetic cores 40a and 40b. An example of such a resin is a potting resin.

As shown in FIG. 5 and FIG. 6A, the coil 300 wound around the bobbin main body 21 of the bobbin 20 has a first coil portion 301 along the winding axis of the coil 300 (substantially parallel to the Z axis). It has the 2nd coil part 302 and the intermediate coil part 303 located between these 1st coil parts 301 and the 2nd coil part 302. That is, in the present embodiment, the intermediate coil portion 303 is sandwiched between the first coil portion 301 and the second coil portion 302 along the winding axis (Z-axis direction) of the coil 300.

The intermediate coil portion 303 is composed of an intermediate wire (first wire) 37, and the first coil portion 301 and the second coil portion 302 form the first coil portion 301 and the second coil portion 302. It is composed of a common wire (second wire) 38.

In the present embodiment, the common wire 38 constitutes a primary coil and the intermediate wire 37 constitutes a secondary coil. That is, as shown in FIG. 11, the first coil portion 301 and the second coil portion 302 formed of the common wire 38 are the primary windings, and the intermediate coil portion 303 formed of the intermediate wire 37 is the secondary winding. By forming a line, a transformer is formed between the two.

In the present embodiment, a higher voltage acts on the primary coil than a secondary coil, and a relatively low voltage acts on the secondary coil. Here, La shown in FIG. 11 is a leakage inductance.

Each of the wires 37 and 38 may be formed of a single wire, or may be formed of a stranded wire, or one of the wires may be a single wire and the other may be a stranded wire. The wires 37 and 38 may be made of the same material or different. The outer diameters of the wires 37 and 38 are not particularly limited, but are preferably in the range of 1.0 to 4.0 mm. In the present embodiment, since the current flowing through the secondary coil is large, the outer diameter of the intermediate wire 37 is larger than the outer diameter of the common wire 38, and for example, 3.0 to 4.0 mm is preferable. Further, it is preferable that each wire 37, 38 is formed with an insulating coating.

The first lead portions 37a and 37b shown in FIG. 1 are both ends of the intermediate wire 37 shown in FIGS. 5 and 6A, and the second lead portions 38a and 38b shown in FIG. 1 are the same as those shown in FIGS. 5 and 6A. Both ends of the wire 38. As shown in FIG. 1, terminals 94 made of, for example, metal terminals are connected to the respective ends of the first lead portions 37a, 37b and the second lead portions 38a, 38b by soldering or the like, and the respective wires 37 are connected. Both ends of 38 and 38 are electrically connected to terminal 94.

In the present embodiment, when the number of turns of the intermediate wire 37 forming the intermediate coil portion 303 is n2, the total number of turns n1 of the common wire 38 in the first coil portion 301 and the second coil portion 302 is preferably n2. 2 times or more, 3 times or more, 5 times or more, 6 times or more. In the present embodiment, even if the ratio (n1/n2) of these winding numbers is large, the coupling coefficient can be made relatively large, which contributes to stabilization of the leakage characteristic.

The total number of turns n1 of the common wire 38 in the first coil portion 301 and the second coil portion 302 is preferably divided into the first coil portion 301 and the second coil portion 302 substantially evenly, but may be slightly different. That is, the number of turns of the common wire 38 in the first coil unit 301 is preferably (0.3 to 0.7)×n1, and the number of turns of the common wire 38 in the second coil unit 302 is (0. It is preferably 7 to 0.3)×n1. This is to improve the coupling coefficient between the primary coil and the secondary coil.

As illustrated in FIG. 9, the common wire 38 has an inter-coil connecting portion 380 that extends between the first coil portion 301 and the second coil portion 302 in the winding axis (Z axis) direction. In the present embodiment, since the first coil portion 301 and the second coil portion 302 are continuously formed by the common wire 38, the common wire 38 has a space between the first coil portion 301 and the second coil portion 302. Thus, the inter-coil connecting portion 380 extending in the winding axis direction is formed.

As shown in FIGS. 6A and 9, the inter-coil connecting portion 380 passes inside the intermediate coil portion 303. Although details will be described later, in the present embodiment, the common wire 38 is first wound around the bobbin 20 to form the first coil portion 301 and the second coil portion 302, and then the intermediate wire 37 is wound around the bobbin 20. The intermediate coil unit 303.

When the coil 300 is mounted on the bobbin 20 in this manner, the inter-coil connecting portion 380 passes inside the intermediate coil portion 303. In this case, as shown in FIG. 6A, a first insulating cover 81 is attached to the bobbin 20 in order to insulate the inter-coil connecting portion 380 from the intermediate coil portion 303. The first insulating cover 81 will be described in detail later.

As shown in FIG. 6A, a pair of second lead portions 38a and 38b are drawn out from the first coil portion 301 and the second coil portion 302. Further, a pair of first lead portions 37a and 37b are drawn out from the intermediate coil portion 303.

More specifically, as shown in FIG. 8A, the first lead portions 37a and 37b formed at both ends of the intermediate wire 37 have first rising portions 371a and 371a extending in the winding axis (Z-axis) direction of the coil 300. 371b, first direction changing portions 372a and 372b directed in a direction in which the distance between the pair of first lead portions 37a and 37b is narrowed, and first lead body portions 373a and 373b extending in a direction away from the coil 300 (X axis). Have.

The first rising portions 371a and 371b may not necessarily be parallel to the Z axis and may be inclined. Further, the first drawer body portions 373a and 373b are not necessarily parallel to the X axis, and may be inclined in the Y axis and/or Z axis directions. The first direction changing portions 372a and 372b are portions that convert the direction toward the first rising portions 371a and 371b into the direction toward the first drawer body portions 373a and 373b, and may be linear or curved.

In the present embodiment, the distance between the first drawer body portions 373a and 373b is configured to be narrower than the distance between the first rising portions 371a and 371b. More specifically, the gap distance W1 between the first drawer body portions 373a and 373b is preferably 0 to 1 mm. The length L1 of the first drawer body 373a, 373b in the X-axis direction is preferably 20 to 100 mm. As the gap distance W1 is smaller, the leakage of the secondary coil can be smaller. Further, the length L1 of the first drawer main body portions 373a and 373b in the X-axis direction tends to increase the leakage as the length increases, and therefore the minimum necessary amount is preferable.

Further, as shown in FIG. 8A, the second lead portions 38a and 38b formed at both ends of the common wire 38 include second rising portions 381a and 381b extending in the winding axis (Z-axis) direction of the coil 300, The pair of second lead portions 38a, 38b has second direction changing portions 382a, 382b extending in a direction in which the distance between the second lead portions 38a, 38b increases, and second lead body portions 383a, 383b extending in a direction away from the coil 300 (Y axis).

The second rising portions 381a and 381b may not necessarily be parallel to the Z axis and may be inclined. Also, the second drawer main body portions 383a and 383b are not necessarily parallel to the X axis, and may be inclined in the Y axis and/or Z axis directions. The second direction changing portions 382a and 382b are similar to the first direction changing portions 372a and 372b, and may be linear or curved.

In the present embodiment, the interval between the second drawer main body portions 383a and 383b is configured to be wider than the interval between the second rising portions 381a and 381b. More specifically, the gap distance W2 between the second drawer body portions 383a and 383b is wider than the gap distance W1 between the drawer body portions 373a and 373b, and preferably 1 to 5 mm. Further, the length L2 of the second drawer main body portions 383a, 383b in the X-axis direction is substantially the same as the length L1 of the first drawer main body portions 373a, 373b in the X-axis direction.

In addition, in the present embodiment, the interval between the first drawer main body parts 373a and 373b and the interval between the second drawer main body parts 383a and 383b are constant in each part in the longitudinal direction, but may be different. .. That is, the first drawer body portions 373a, 373b or the second drawer body portions 383a, 383b do not necessarily have to extend in parallel. However, from the viewpoint of improving the leakage characteristics of the transformer 10, it is preferable that the gap distance W1 between the first drawing main body portions 373a and 373b be reduced and the gap distance W1 be constant along the longitudinal direction.

As shown in FIG. 7A, the bobbin 20 has a bobbin main body 21, and a first terminal block 22 and a second terminal block 23 that are integrally molded on both upper ends of the bobbin main body 21 in the X-axis direction. The bobbin 20 is made of plastic such as PPS, PET, PBT, LCP, or nylon, but may be made of other insulating member. However, in this embodiment, the bobbin 20 is preferably made of plastic having a high thermal conductivity of, for example, 1 W/m·K or more, and is made of, for example, PPS or nylon.

The terminal blocks 22 and 23 have side wall portions 221 and 231 and a pair of first and second locking portions 222 and 232 formed at both ends in the X-axis direction. The side wall portions 221 and 231 are formed so as to surround the peripheral edges of the terminal blocks 22 and 23 except for the side where the first lead portions 37a and 37b and the second lead portions 38a and 38b are pulled out. Engagement protrusions 224 and 234 are formed on both outer end walls of the side walls 221 and 231 in the Y-axis direction. Functions of the engaging protrusions 224 and 234 will be described later. In the first terminal block 22, a separation convex portion 223 is formed at an intermediate position in the Y axis direction between the pair of first locking portions 222.

As shown in FIG. 7B, in the pair of first locking portions 222, the first lead portions 37a and 37b raised in the Z-axis direction at the first rising portions 371a and 371b are connected to the first direction changing portions 372a and 372a. The portion 372b is wound from the outer side to the inner side in the Y-axis direction, and is guided to the outer side in the X-axis direction as the first draw-out main body portions 373a and 373b with a small gap therebetween.

The separation convex portion 223 has a substantially pentagonal shape when viewed from the Z axis, and has a tip portion that tapers in the direction away from the bobbin 20 in the X axis direction. The separation convex portion 223 is a member for separating the first direction changing portions 372a and 372b from each other or the first drawing main body portions 373a and 373b so as not to contact each other. It should be noted that the shape of the separation convex portion 223 is not limited to the illustrated shape, and may be appropriately changed to an elliptical shape or another polygonal shape.

By locking the first direction changing parts 372a, 372b of the first lead parts 37a, 37b between the pair of first locking parts 222 and the separation convex part 223, the first lead parts 37a, 37b are respectively moved to the first lead parts 37a, 37b. The first locking portions 372a and 372b are locked without slack. As a result, unwinding of the intermediate coil portion 303 formed of the intermediate wire 37 located in the middle of the first lead portions 37a and 37b shown in FIG. 8A is prevented. In this state, the first lead portions 37a and 37b can be pulled out in the direction away from the coil 300. That is, in the present embodiment, as shown in FIG. 7B, the first terminal block 22 is partitioned (or sandwiched by the side wall portion 221, the pair of first locking portions 222, and the separation convex portion 223). ) Passages are formed, and the first lead portions 37a and 37b can be pulled out in a direction away from the bobbin 20 through these passages.

Further, as shown in FIG. 4, in the pair of second locking portions 232, the second lead portions 38a and 38b raised in the Z-axis direction at the second rising portions 381a and 381b are the second direction changing portions 382a. , 382b are wound from the inner side to the outer side in the Y-axis direction, and are guided to the outer side in the X-axis direction as the second drawer main body portions 383a and 383b with a large gap therebetween. The second terminal block 23 does not need to be provided with a member similar to the separation protrusion 223 provided on the first terminal block 22.

By locking the second direction changing parts 382a, 382b of the second lead parts 38a, 38b to the pair of second locking parts 232, each of the second lead parts 38a, 38b does not loosen in the second locking part 232. Be locked. As a result, it is possible to prevent the unwinding of the first coil portion 301 and the second coil portion 302 formed of the common wire 38 located in the middle of the second lead portions 38a and 38b shown in FIG. It is possible to pull out the lead portions 38a and 38b in the direction away from the coil 300. That is, in the present embodiment, as shown in FIG. 7A, the second terminal block 23 has a passage defined by (or sandwiched by) the side wall portion 231 and the pair of second locking portions 232. The second lead portions 38a, 38b can be pulled out in a direction away from the bobbin 20 through these passages.

As shown in FIG. 2, a lead wire cover 60 is mounted above the terminal blocks 22 and 23 in the Z-axis direction so as to cover them. More specifically, holes 61 are formed in the side surfaces of the drawing wire cover 60 at both ends in the Y-axis direction, and the holes 61 are engaged with the engaging protrusions 224, 234 formed in the terminal blocks 22, 23. By fitting them together, the lead wire cover 60 can be attached to the terminal blocks 22 and 23. Accordingly, it is possible to prevent the first lead portions 37a and 37b and the second lead portions 38a and 38b from unnecessarily protruding above the terminal blocks 22 and 23.

In the present embodiment, the magnetic cores 40a and 40b have the same shape and have an E-shaped cross section in the Z-Y cross section, and configure a so-called E-shaped core. The mode of the magnetic cores 40a and 40b is not limited to the mode shown in FIG. 2, and the magnetic cores 40a and 40b are arranged parallel to the XZ plane along the dashed line (approximately the center position in the Y-axis direction) in the figure. It may be a split core obtained by cutting.

The magnetic core 40a arranged on the upper side in the Z-axis direction includes a base portion 44a extending in the Y-axis direction, a pair of side leg portions 48a projecting in the Z-axis direction from both ends of the base portion 44a in the Y-axis direction, and these. And the middle leg portion 46a protruding in the Z-axis direction from the center in the Y-axis direction between the side leg portions 48a. The magnetic core 40b arranged on the lower side in the Z-axis direction includes a base portion 44b extending in the Y-axis direction, a pair of side leg portions 48b protruding in the Z-axis direction from both ends of the base portion 44b in the Y-axis direction, Between these side leg portions 48b, there is an intermediate leg portion 46b protruding in the Z-axis direction from the center in the Y-axis direction.

The middle leg portion 46a is adapted to be inserted into the core leg through hole 21a of the bobbin 20 from above in the Z-axis direction. Similarly, the middle leg portion 46b is inserted into the core leg through hole 21a of the bobbin 20 from below in the Z-axis direction, and the tips thereof have a predetermined gap G (in the core leg through hole 21a). 5 and 6A) (see FIG. 5 and FIG. 6A).

By forming the gap G in this way, the leakage characteristics can be adjusted according to the width of the gap G. The tip of the middle leg 46b may be configured to contact the tip of the middle leg 46a inside the core leg through hole 21a without forming the gap G.

The middle leg portion 46a and the middle leg portion 46b have a substantially elliptic cylindrical shape so as to match the inner peripheral surface shape of the core leg through hole 21a, but the shape is not particularly limited, and the core leg portion is not particularly limited. It may be changed according to the shape of the through hole 21a for use. The side leg portions 48a and 48b have an inner concave curved surface shape that matches the outer peripheral surface shape of the bobbin main body 21, and the outer surface thereof has a plane parallel to the XZ plane. In the present embodiment, the material of each core 40a, 40b may be a soft magnetic material such as metal or ferrite, but is not particularly limited.

Covers 50 are arranged between the inner peripheral surfaces of the side leg portions 48a and 48b and the outer peripheral surface of the bobbin main body 21, respectively. The cover body 52 of the cover 50 has a shape that covers the outer periphery of the bobbin body 21 located between the terminal blocks 22 and 23 of the bobbin 20. Locking pieces 54, which are bent in a substantially vertical direction from the cover body 52 toward the bobbin body 21, are integrally formed at both ends of the cover body 52 in the Z-axis direction. As shown in FIG. 4, the pair of locking pieces 54 formed on both sides of the cover body 52 in the Z-axis direction are attached so as to sandwich the upper and lower surfaces of the bobbin body 21 in the Z-axis direction.

Side leg guide pieces 56 extending in the Z-axis direction are integrally formed on the outer surfaces of both ends of the cover body 52 in the X-axis direction. The inner surfaces of the side leg portions 48a and 48b come into contact with the outer surface of the cover main body 52 located between the pair of side leg guide pieces 56, so that the movement of the side leg portions 48a and 48b in the X-axis direction is prevented. It is designed to be restricted by the guide piece 56. These covers 50 are made of the same insulating material as plastic such as the bobbin 20 or metal.

As shown in FIG. 5, at both ends in the Z-axis direction of the winding tubular portion 28 constituting the bobbin main body 21 of the bobbin 20, end partition wall flanges 24 and 25 are extended in the XY plane so as to extend outward in the radial direction. Is formed substantially parallel to. On the outer peripheral surface of the winding tubular portion 28 located between the end partition ribs 24 and 25 in the Z-axis direction, the winding partition ribs 26 and 27 are predetermined in the Z-axis direction so as to project radially outward. It is formed at intervals. By the winding partition ribs 26 and 27 formed between the end partition ribs 24 and 25, partitions S1 to S3 are formed between these partition ribs in order from the bottom in the Z-axis direction. The numbers of the winding partition ribs 26 and 27 and the sections S1 to S3 are not particularly limited.

In the present embodiment, the common wire 38 is continuously wound by 6 turns in each of the sections S1 and S3 to form the first coil portion 301 and the second coil portion 302, and the intermediate wire 37 is provided in the section S2. The third coil unit 303 is wound by one turn. In the present embodiment, the winding partition rib 26 plays a role of partitioning the first coil portion 301 and the intermediate coil portion 303 in the Z-axis direction, and the winding partition rib 27 forms the second coil portion 302 and the intermediate coil portion 303. And plays a role of partitioning in the Z-axis direction.

As shown in FIG. 5, the partition width T1 along the Z-axis in the partitions S1 and S3 around which the common wire 38 forming the first coil portion 301 is wound is one common wire 38 in the Z-axis direction. The width is set so that it can enter. However, the partition width T1 may be set to a width that allows two or more common wires 38 to enter in the Z-axis direction. Further, in the present embodiment, the partition widths T1 are preferably all the same, but may be slightly different.

The partition width T2 along the Z-axis in the partition S2 around which the intermediate wire 37 forming the intermediate coil portion 303 is wound is set to a width that allows one intermediate wire 37 to enter in the Z-axis direction. However, the partition width T2 may be set to a width that allows two or more intermediate wires 37 to enter in the Z-axis direction. Further, in the present embodiment, the partition width T2 along the Z axis in the partition S2 is preferably different from the partition width T1 according to the wire diameter of the common wire 38, but may be the same.

Further, the height (the length in the radial direction with respect to the winding axis) H1 of the partition ribs 24 to 27 is set to a height at which one or more wires (one or more layers) 37 or 38 can enter. In the form, the height is preferably set so that 3 to 8 layers of wire can be wound. The heights H1 of the partition ribs 24 to 27 are preferably the same, but may be different.

In the present embodiment, the winding method of the common wire 38 wound in the sections S1 and S3 is α winding, and the common wire is wound in the sections S1 and S3 shown in FIG. 5 from the inter-coil connecting portion 380 shown in FIG. 38 is passed through to start winding, and is drawn out to the lead portions 38a and 38b shown in FIG. 8A. The winding method of the intermediate wire 37 wound around the section S2 shown in FIG. 5 is not particularly limited and may be normal winding or α winding.

Here, α winding will be described. For example, in order to wind the common wire 38 around the bobbin 20 shown in FIGS. 6A and 6B by α, first, the coil of the common wire 38 is formed in a portion where the winding partition wall flanges 26 and 27 are partially cut out in the circumferential direction. The section S1 and the section S3 shown in FIG. 5 are connected to each other through the inter-connecting section 380. Then, a part of the common wire 38 on the side closer to the lead portion 38a is wound in a plurality of layers (6 layers in the present embodiment) around the outer periphery of the winding tubular portion 28, for example, in the clockwise direction inside the section S3. .. At the same time, the other part of the common wire 38 on the side closer to the lead portion 38b is disposed inside the section S1 in the direction opposite to the winding direction in the section S1 (or may be the same direction), and the other portion of the winding tubular section 28 is formed. Wrap around the outer periphery in multiple layers. Note that these operations may be performed using an automatic winding machine.

As shown in FIG. 6A, the intermediate wire 37 wound in the section S2 shown in FIG. 5 has a portion between the coil of the common wire 38 at a portion where the winding partition wall flanges 26 and 27 are partially cut out in the circumferential direction. After arranging the connecting portion 380, the first insulating cover 81 is mounted, and thereafter, as shown in FIG. 5, it is wound one or more times between the winding partition ribs 26 and 27.

As shown in FIGS. 6A and 7A, bobbin legs 29 are integrally formed at both ends in the X-axis direction of the end partition rib 25 located at the lowermost portion in the Z-axis direction. Each bobbin leg portion 29 is formed so as to project downward in the Z-axis direction from both ends in the X-axis direction of the end partition wall collar 25. Each bobbin leg 29 accommodates each pedestal 70 shown in FIG. The height of each pedestal 70 in the Z-axis direction is adjusted so that the bottom surface of each pedestal 70 is substantially flush with the bottom surface of the core member 40b when the pedestal 70 is accommodated in each bobbin leg 29. .. That is, the pedestal 70 also has a function as a height adjusting mechanism.

As shown in FIG. 7A, on the second terminal block 23 side of the winding partition ribs 26, 27, cutouts 264, 274 are formed with a width narrower than the Y-axis direction width of the first insulating cover 81 shown in FIG. 7C. Has been formed. Further, a counterbore surface 261 that does not penetrate in the Z-axis direction is formed on the lower surface of the winding partition wall flange 26 in the Z-axis direction at the circumferential position where the notch 264 is formed. Further, a counterbore surface 271 that does not penetrate in the Z-axis direction is formed on the upper surface of the winding partition rib 27 in the Z-axis direction at the circumferential position where the notch 274 is formed.

A first insulating cover 81 shown in FIG. 7C is attached between the winding partition ribs 26 and 27 along the counterbore surfaces 261 and 271 to close the notches 264 and 274. As shown in FIG. 7C, the first insulating cover 81 is for insulating the inter-coil connecting portion 380 from the intermediate coil portion 303. In addition, as shown in FIG. 7A, a lead locking groove 272 is formed in the countersunk surface 271. The base end of the second rising portion 381b of the second lead portion 38b is locked in the lead locking groove 272 to facilitate the formation of the second rising portion 381b.

As shown in FIG. 7C, the first insulating cover 81 includes an intermediate partial cylinder 813 forming a part of a cylinder, a partial collar 811 formed parallel to the XY axis plane at both ends in the Z axis direction, and 812 and. The intermediate partial cylinder 813 is formed by winding a part of the intermediate wire 37 constituting the intermediate coil portion 303 in the circumferential direction. As shown in FIG. 6A, the inner peripheral surface of the intermediate partial cylinder 813 faces the outer peripheral surface of the winding cylinder portion 28 of the bobbin 20 with the inter-coil connecting portion 380 interposed therebetween.

In the first insulating cover 81, one partial brim 811 abuts on the counterbore surface 261 of the winding partition wall portion 26, and the other partial brim 812 abuts on the counterbore surface 271 of the winding partition wall portion 27 to enable the slide insertion. , Fixed to the bobbin 20. As shown in FIG. 9, in the present embodiment, the inter-coil connecting portion 380 passes inside the intermediate coil portion 303, but as shown in FIG. 7C, the inter-coil connecting portion 380 and the intermediate coil portion 303 are intermediate. It is insulated via the partial cylinder 813.

As shown in FIG. 6A, cutouts 244 and 264 are formed on the end terminal partition wall flange 24 and the winding partition wall flange 26 on the side of the first terminal block 22 so that the second insulating cover 82 shown in FIG. 7D can be attached. I have it. As shown in FIG. 8B, the second insulating cover 82 includes the first rising portions 371a and 371b of the first lead portions 37a and 37b and the first direction changing portions 372a and 372b, and the first coil portion 301 (second wire). To insulate from the common wire 38).

As shown in FIG. 7D, the second insulating cover 82 has partial collars 821 and 822 formed at both ends in the Z-axis direction in parallel in the X-Y axis plane, a wall portion 823, and a pair of side portions 824. Have and. Protrusions 825 are formed on the outer surface of the side portion 824 in the Y-axis direction. As shown in FIG. 6A, in the second insulating cover 82, one partial brim 821 is fitted in a groove formed in the end partition wall portion 24, and the other partial brim 822 is brought into contact with the counterbore surface of the winding partition wall portion 26. The bobbin 20 is fixed by being brought into contact with each other and slidingly inserted.

At that time, as shown in FIG. 7B, the convex portion 825 formed on the second insulating cover 82 has the Y-axis direction end portion of the winding partition wall collar 26 and the Y-axis direction end portion of the end partition wall portion 24 ( The second insulating cover 82 is stably fixed to the bobbin 20 by engaging with the lower end of the side wall portion 221. As shown in FIGS. 8B and 8C, the first rising portions 371a and 371b of the first lead portions 37a and 37b and the first coil portion 301 are well insulated from each other via the second insulating cover 82. As shown in FIG. 7B, since the winding partition wall flange 27 has an overhanging portion that projects outward in the X-axis direction (a direction away from the winding axis of the bobbin 20), the intermediate portions shown in FIGS. 8B and 8C are shown. The insulation between the wire 37 and the first lead portions 37a and 37b thereof and the second coil portion 302 is also maintained well.

These insulating covers 81, 82 are made of an insulating material such as plastic which is similar to or different from the bobbin 20. The insulating covers 81 and 82 are molded separately from the bobbin 20 and attached to a part of the bobbin 20 in the circumferential direction.

The transformer 10 according to the present embodiment is manufactured by assembling the members shown in FIG. 2 and winding the intermediate wire 37 and the common wire 38 around the bobbin 20. Hereinafter, an example of a method of manufacturing the transformer 10 will be described with reference to FIG. In manufacturing the transformer 10, first, the bobbin 20 is prepared. The material of the bobbin 20 is not particularly limited, but the bobbin 20 is formed of an insulating material such as resin.

Next, the common wire 38 is wound around the outer circumference of the winding tubular portion 28 of the bobbin 20 by α winding to form the first coil portion 301 and the second coil portion 302. The common wire 38 used to form the first coil portion 301 and the second coil portion 302 is not particularly limited, but a litz wire or the like is preferably used. The second lead portions 38a and 38b, which are the end portions of the common wire 38 when forming the first coil portion 301 and the second coil portion 302, are soldered and connected to the terminal 94, for example.

Next, the first insulating cover 81 and the second insulating cover 82 are attached to the bobbin 20 around which the common wire 38 is wound. The second insulating cover 82 may be attached to the bobbin 20 later, and it is sufficient that at least the first insulating cover 81 is attached to the bobbin 20.

Next, the intermediate wire 37 is wound around the outer circumference of the winding tubular portion 28 of the bobbin 20 to form the intermediate coil portion 303. The intermediate wire 38 used for forming the intermediate coil portion 303 may be the same as or different from the common wire 38. The first lead portions 37a and 37b, which are the end portions of the intermediate wire 37 when the intermediate coil portion 303 is formed, are soldered and connected to the terminal 94, for example.

Next, the first lead portions 37a and 37b are pulled out from the intermediate coil portion 303 to the upper side of the winding axis, and are pulled out in the direction away from the coil 300 while being locked by the first locking portion 222. At that time, the second insulating cover 82 is attached to the bobbin 20 in advance.

In addition, the second lead portions 38a and 38b are pulled out from the first coil portion 301 and the second coil portion 302 above the winding axis, and are pulled out in the direction away from the coil 300 while being locked by the locking portions 222 and 232. Then, the lead wire cover 60 is mounted above the terminal blocks 22 and 23.

Next, the covers 50 are attached to both sides of the bobbin 20 in the Y-axis direction, and then the magnetic cores 40a and 40b are attached from the vertical direction in the Z-axis direction. That is, the tips of the side legs 48a, 48b are joined together while leaving a gap G between the tips of the middle legs 46a, 46b of the magnetic cores 40a, 40b. Examples of the material of the magnetic cores 40a and 40b include soft magnetic materials such as metal and ferrite, but are not particularly limited. The gap G may be 0.

Next, the pedestal 70 is housed inside the bobbin leg portion 29. The pedestal 70 may be attached to the bobbin leg 29 in advance. Then, the bottom plate 92 is adhered to the bottom opening of the case 90, the assembly is housed in the case 90 having an open upper portion, and the inside of the case 90 is filled with heat dissipation resin. The transformer 10 according to the present embodiment can be manufactured by the above steps.

The transformer 10 according to the present embodiment has a structure (sandwich structure) in which the intermediate coil portion 303 is sandwiched between the first coil portion 301 and the second coil portion 302. Therefore, the coupling between these coil portions can be increased, and the leakage characteristics can be easily stabilized. Further, it is possible to realize the highly coupled transformer 10 that can obtain stable leakage characteristics even in a high frequency band.

Further, the first coil portion 301 and the second coil portion 302 are continuously formed by the common wire 38. With such a configuration, it is possible to prevent the current from flowing unevenly in one of the first coil portion 301 and the second coil portion 302. Since the electric current is prevented from being biased, it is possible to prevent abnormal heat generation in either one of the coil portions 301 or 302. In addition, the wire length of the common wire 38 forming the first coil portion 301 and the second coil portion 302 is shortened as compared with the case where the first coil portion 301 and the second coil portion 302 are formed by separate wires. It is possible to reduce copper loss. If copper loss can be reduced, efficiency can be improved and heat generation can be reduced.

Further, in this embodiment, since the coupling coefficient between the primary coil and the secondary coil is high, the leakage characteristic is stabilized even when the number of turns of the primary coil and the number of turns of the secondary coil are significantly different. It is easy to do. That is, according to this embodiment, the effect is large even when the winding ratio of the number of turns of the common wire 38 in the first coil portion 301 and the second coil portion 302 to the number of turns of the intermediate wire 37 in the intermediate coil portion 303 is large. Specifically, even when the winding number ratio n1/n2 of the total winding number n1 of the common wire 38 and the winding number n2 of the intermediate wire 37 is 2 or more, 3 or more, 5 or more, a more remarkable effect is obtained.

Further, in the present embodiment, the common wire 38 is wound around the bobbin 20 by α. With such a configuration, the single common wire 38 can be used to easily form the first coil portion 301 and the second coil portion 302 that are arranged apart from each other in the winding axis direction. It is also easy to make the number of turns of the coil the same between the first coil portion 301 and the second coil portion 302, and it is also easy to change the number of turns.

Further, as shown in FIG. 5, in each of the first coil portion 301 and the second coil portion 302, the collar portions 24 to 27 of the bobbin 20 are provided so that only the single wire 38 exists along the winding axis direction. By adjusting the intervals T1 and T2, it becomes easy to prevent variations in the number of windings of the wires 37 and 38 per layer, which contributes to stabilization of the leakage characteristics. That is, it becomes easy to strictly control the coupling coefficient between the primary coil and the secondary coil.

Further, since the α winding can reduce the number of layers in the winding axis direction even if the number of windings is increased, it contributes to reduction in height and size of the coil device 10. Further, since the wire is not pulled out from the central portion of the winding by forming the α winding, the wires do not overlap each other, which contributes to the reduction in height of the coil device 10.

Particularly, in the present embodiment, as shown in FIG. 8A, the pair of first lead portions 37a and 37b are pulled out from the intermediate coil portion 303 along the Z axis at the first rising portions 371a and 371b, and then in the first direction. The changing portions 372a and 372b are bent in a direction in which the distance between the pair of first lead portions 37a and 37b is narrowed, and then the first lead body portions 373a and 373b are moved away from the coil 300.

That is, in the coil device 10 according to the present embodiment, the gap distance W1 between the pair of first drawer main body portions 373a and 373b is narrower than the gap distance between the pair of first rising portions 371a and 371b. Therefore, the pair of first lead portions 37a and 37b are pulled out from the intermediate coil portion 303 in a state of being separated from each other, stand up along the Z axis, and then come close to each other. The inventors of the present invention have found that such a lead-out structure makes it possible to realize a coil device having stable leakage characteristics as compared with a conventional coil device.

Experiments by the present inventors have revealed that the leakage can be reduced to 3/4 or less as compared with the conventional coil device only by changing the drawing structure of the pair of first lead portions 37a and 37b. In particular, it has been confirmed that it is particularly effective when the ratio of the number of turns between the primary coil and the secondary coil is large.

Further, in the present embodiment, the rising direction of the first rising portions 371a and 371b and the rising direction of the second rising portions 381a and 381b are the same direction (upward direction in the Z-axis direction). Therefore, as shown in FIG. 2, the second terminal block 23 is located on the same upper side of the Z axis with respect to the first terminal block 22. With this configuration, it becomes easy to position the bottom surface of the bobbin 20 located on the opposite side of the first terminal block 22 and the second terminal block 23 along the Z-axis on the cooling side, as shown in FIG. The cooling efficiency of the coil 300, the bobbin 20, and the cores 40a and 40b is improved.

Further, in the above-described embodiment, as shown in FIG. 8A, the pair of second lead portions 38a, 38b is different from the pair of first lead portions 37a, 37b in that the distance between the second rising portions 381a, 381b The second lead-out main body portions 383a and 383b extend in a direction away from the coil 300 while maintaining a wide distance W2. Such a structure is preferable when the voltage applied to the second lead portions 38a and 38b is high. However, like the pair of first lead portions 37a and 37b, the pair of second lead portions 38a and 38b are separated from the coil 300 while keeping a distance narrower than the distance between the second rising portions 381a and 381b. Alternatively, the second drawer main body portions 383a and 383b may extend.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

For example, as another mode of mounting the coil 300 on the outer circumference of the bobbin 20, the intermediate wire 37 is first wound around the bobbin 20 to form the intermediate coil portion 303, and then the common wire 38 is wound around the bobbin 20, A mode in which the first coil portion 301 and the second coil portion 302 are configured is also conceivable. When the coil 300 is attached to the bobbin 20 in this manner, the inter-coil connecting portion 380 passes outside the intermediate coil portion 303.

Further, the relationship between the primary coil and the secondary coil described above may be reversed. That is, the common wire 38 may form a secondary coil and the intermediate wire 37 may form a primary coil. In that case, the size relationship of the outer diameters of the wires may be opposite to that in the above-described example. Alternatively, the outer diameters of these wires may be the same.

10... Transformer 20... Bobbin 21... Bobbin main body 21a... Core leg through hole 22... First terminal block 23... Second terminal block 221, 231... Side wall part 222... First locking part 232... Second locking part 223 ... Separation convex part 224, 234... Engagement projection part 24, 25... End partition wall flange 244... Notch part 26, 27... Rolling partition wall flange 261, 271... Counterbore surface 272... Lead locking groove 264, 274... Notch part 28... Winding tube part 29... Bobbin leg part 300... Coil part 301... First coil part 302... Second coil part 303... Intermediate coil part 37... Intermediate wire 37a, 37b... First lead part 371a, 371b... First Standing portions 372a, 372b... First direction changing portion 373a, 373b... First drawing main body portion 38... Common wire 38a, 38b... Second lead portion 381a, 381b... Second rising portion 382a, 382b... Second direction changing portion 383a , 383b... Second drawer main body 380... Inter-coil connecting portions 40a, 40b... Magnetic cores 44a, 44b... Base portions 46a, 46b... Middle leg portions 48a, 48b... Side leg portions 50... Cover 52... Cover body portion 54... Locking piece 56... Side leg guide piece 60... Draw-out wire cover 70... Pedestal 81... First insulating cover 811, 812... Partial collar 813... Intermediate partial cylinder 82... Second insulating cover 821, 822... Partial collar 823... Wall part 824... Side part 825... Convex part 90... Case 91... Boss part 92... Bottom plate 94... Terminal

Claims (9)

A coil device having a bobbin and a coil mounted on the outer periphery of the bobbin,
The pair of first lead portions that are drawn from the coil and that are formed by both ends of the first wire,
A pair of first rising portions extending in the winding axis direction of the coil;
A pair of first drawer main body portions extending in a direction away from the coil while maintaining a distance smaller than a distance between the pair of first rising portions;
A pair of first direction changes that connect the first rising portion and the first drawer body portion and change the direction of the first rising portion toward the direction of the first drawer body portion. Department,
Have a,
The coil has a first coil portion, a second coil portion, and an intermediate coil portion located between the first coil portion and the second coil portion, along a winding axis of the coil. ,
The intermediate coil portion is composed of the first wire,
The first coil portion and the second coil portion are configured by a second wire for continuously forming the first coil portion and the second coil portion,
A coil device , wherein a ratio n1/n2 of the total number of turns n1 of the second wire and the number of turns n2 of the first wire in the first coil part and the second coil part is 2 or more . A first terminal block is formed on the bobbin, and the first lead block raised at the first rising portion is provided outside the first terminal block at the position of the first direction changing portion. The coil device according to claim 1, wherein a pair of first locking portions is formed that is wound inward from the inside and is guided toward the first drawer main body portion. The pair of first lead portions located between the pair of first locking portions and guided from the first direction changing portion to the first drawer main body portion are guided to the first terminal block, The coil device according to claim 2, wherein a separation convex portion for forming a predetermined gap is formed between the pair of the first drawer main body portions. Wherein the first wire consists of two ends of different ones of the second wire, further comprising a second lead portions of the pair drawn from the coil,
The pair of second lead portions includes
A pair of second rising parts extending in the winding axis direction of the coil;
A pair of second drawer main body portions extending in a direction away from the coil while maintaining a distance wider than a distance between the pair of second rising portions;
A pair of second direction changes that connect the second rising portion and the second drawer main body portion and change the direction of the second rising portion toward the direction of the second drawer main body portion. The coil device according to claim 1, further comprising: A second terminal block is formed on the bobbin, and the second lead part raised at the second rising portion is provided inside the second terminal block at the position of the second direction changing part. The coil device according to claim 4, further comprising a pair of second locking portions that are wound from the outside to the outside and are guided toward the second drawer main body portion. The rising direction of the first rising portion and the rising direction of the second rising portion are the same,
The coil device according to claim 5, wherein the second terminal block is located on the same side of the winding axis of the coil as the first terminal block formed on the bobbin. The bobbin is provided inside the first rising portion in order to ensure insulation between a portion where the second wire forming a part of the coil is wound around the bobbin and the first rising portion. The coil device according to any one of claims 4 to 6, wherein an insulating cover is attached to the outer periphery of the coil device. The first wire constitutes either one of a primary coil or a secondary coil, and the second wire constitutes either the other of a primary coil or a secondary coil. The coil device according to any one of 1 to 7 . The number of turns of the first wire bobbin are wound on the coil apparatus according to any one of the smaller claim than the number of turns in the second wire that is wound around the bobbin 1-8.

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