JP2020136593A - Transformer device - Google Patents

Abstract

To provide a transformer device which is made low in height and downsized while securing a sufficient insulation distance.SOLUTION: A transformer device comprises: a coil component in which a primary coil and a secondary coil are formed around a magnetic core; and a resin case 200 in which a coil component 10 is accommodated. In the coil component, three lead wires are directly wound in a spiral shape around an annular magnetic core, which consists of NiZn-based ferrite, by trifilar winding, one of the three lead wires is defined as the primary coil and the remaining two are defined as the secondary coils. The resin case is hexahedron structure in which one front face is an open face and the other five faces are constituted of a lower base part, three right, left and rear wall parts erected from three edges of the base part, and a top plate part positioned in upper ends of the wall parts and opposed to the base part. The coil component is adhered and fixed in the resin case in a horizontal arrangement state, and the wall parts are interposed between a high-pressure-side metal terminal 110 which is provided in the resin case, and the coil component.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transformer device used in an electronic device.

In recent years, electric vehicles (EVs: Electrical Vehicles) and plug-in hybrid vehicles (EVs), which are equipped with devices such as a driving motor and a battery and drive the driving motor with the power stored in the battery from an external power supply device. PHV: Plug-in Hybrid Electric Vehicle (hereinafter, also referred to as an electric vehicle) has begun to spread. Charging of the battery mounted on the electric vehicle from the external power supply device (EVSE: Electric Vehicle Service Equipment) is performed via a charging cable connected between the power supply device and the electric vehicle. Information is also transmitted and received between the electric vehicle side and the power supply device side by using a charging cable by power line communication (PLC), and signals are superimposed on the charging cable (power line) or superimposed on the power line. A transformer device is used to extract the signal.

FIG. 12 shows a perspective view of the transformer device described in Patent Document 1, and FIG. 13 shows a cross-sectional view thereof. The transformer device 500 is a transformer (hereinafter, referred to as a coil component) including a bobbin 350 in which a high voltage side coil 301 and a low voltage side coil 302 are wound concentrically and a magnetic core 400 incorporated in the bobbin 350. And a resin case 600 for accommodating the coil parts. The resin case 600 is composed of a bottom surface portion in which a metal terminal 650 is embedded, three side surface portions erected from the bottom surface portion, and a top surface portion having a band-shaped opening 605. In the resin case 600, the side surface of the metal terminal 650 to which the end of the low voltage side coil 302 is connected is open, and the side surface of the metal terminal 650 to which the end of the high voltage side coil 301 is connected is open. It is configured to be thicker than the side surface portions of the other side surfaces. The coil parts are housed in the resin case 600 from the opening side of the resin case 600. The end of the high-voltage side coil 301 of the coil component is pulled out along the side surface through the band-shaped opening 605 on the upper surface of the case and connected to the high-voltage side metal terminal 650. The end of the low voltage side coil 302 is connected to the low voltage side metal terminal 650 through an opening on the side surface.

Generally, the insulation distance between each coil is the shortest distance between the exposed conductors of the windings of each coil. In the transformer device 500 described above, the magnetic core 400 is regarded as a conductor having the same potential as the low voltage side coil 302, as well as the distance between the metal terminals 650 to which the ends of the high voltage side coil 301 and the low voltage side coil 302 are connected. The shortest distance between the magnetic core 400 and the exposed conductor of the high-voltage side coil 301 is the insulation distance, and the vertical distance of the side surface of the resin case 600 and the horizontal distance to the band-shaped opening 605 on the upper surface of the case. , It is secured by the space distance between the opening 605 and the magnetic core 400.

Japanese Unexamined Patent Publication No. 2008-258250

With the recent miniaturization of electronic devices, the transformer devices used therein are also required to be further miniaturized while ensuring an insulation distance. The coil component of the conventional transformer device 500 shown in the figure is miniaturized by arranging a bobbin 350 in which a low voltage side coil and a high voltage side coil are concentrically overlapped and wound on an E-shaped magnetic core 400. There is a limit to. Therefore, the space inside the resin case 600 must be expanded according to the outer shape of the coil component, which is an obstacle to the miniaturization of the transformer device 500. Further, the space allowance for storing the transformer may be reduced so as to reduce the size of the transformer device 500, but this is also a factor that makes the assembly work difficult.

Therefore, an object of the present invention is to provide a low-profile, compact transformer device while ensuring a sufficient insulation distance in order to solve the above-mentioned problems.

The present invention is a transformer device including a coil component in which a primary winding and a secondary winding are formed in a magnetic core and a resin case for accommodating the coil component, and the coil component is made of NiZn-based ferrite. Three conductors are spirally wound around the annular magnetic core by a trifilar winding, one of the three conductors is a primary winding, the remaining two are secondary windings, and the resin case is 6. In a face structure, one front surface is an opening surface, and the other five surfaces are a lower base and three wall portions on the right, left, and rear standing from the three edges of the base. It is composed of an integral resin structure portion consisting of a top plate portion facing the base portion at the upper end of the wall portion, and a plurality of metal terminals are provided on the front and rear side surfaces of the base portion, and further, the ceiling portion is provided. The plate portion has a slit-shaped opening at the ridge portion on the rear wall portion side, and the coil component is adhesively fixed to the base portion in a horizontal state and housed in a resin case, and is used for primary winding. The lead wire of the book is pulled out from the opening surface side and connected to the metal terminal on the front side, and the two lead wires for the secondary winding are passed through the slit-shaped opening and the upper end of the rear wall portion. The two conductors for the secondary winding are connected to the metal terminal by being stretched along the outside of the rear wall portion toward the metal terminal on the rear side. It is a transformer device that is adhesively fixed on the upper end side.

In the present invention, the right wall portion and the left wall portion have a protrusion portion on the top plate portion side that projects from the rear wall portion, and is used for the secondary winding. It is preferable that the adhesive fixing portion of the main wire is between the protruding portion of the right wall portion and the protruding portion of the left wall portion.

In the present invention, the NiZn ferrites resistivity ρ is preferably at 10 ⁵ Ω · m or more.

Further, in the present invention, it is preferable that at least the lead wire for the secondary winding is a three-layer insulated electric wire among the lead wires constituting the primary winding and the secondary winding.

According to the present invention, it is possible to provide a low-profile, compact transformer device while ensuring a sufficient insulation distance.

It is a front view of the transformer device which concerns on one Embodiment of this invention. It is a top plan view of the transformer device which concerns on one Embodiment of this invention. It is a bottom plan view of the transformer device which concerns on one Embodiment of this invention. It is a right side view of the transformer device which concerns on one Embodiment of this invention. It is a rear view of the transformer device which concerns on one Embodiment of this invention. It is an equivalent circuit diagram of the transformer device which concerns on one Embodiment of this invention. It is a top view of the coil component used in the transformer device which concerns on one Embodiment of this invention. It is a perspective view for demonstrating the state of winding a lead wire around an annular magnetic core used in the transformer device which concerns on one Embodiment of this invention. It is a perspective view which looked at the resin case used for the transformer device which concerns on one Embodiment of this invention from above. It is a perspective view which looked at the resin case used for the transformer device which concerns on one Embodiment of this invention from the bottom. It is a cross-sectional view of AA of the resin case used for the transformer device which concerns on one Embodiment of this invention. It is a perspective view of the conventional transformer device. It is sectional drawing of the conventional transformer device.

Although embodiments of the transformer device of the present invention will be described, the present invention is not limited to the embodiments described below. FIG. 1 is a front view of a transformer device according to an embodiment of the present invention. 2 is an upper plan view thereof, FIG. 3 is a lower plan view thereof, FIG. 4 is a right side view thereof, and FIG. 5 is a rear view thereof. Further, FIG. 6 is an equivalent circuit diagram of the transformer device according to the embodiment. Further, FIG. 7 is a plan view of a coil component used in the transformer device according to the embodiment of the present invention. FIG. 8 is a perspective view for explaining a state in which a lead wire is wound around an annular magnetic core used in the transformer device according to the embodiment of the present invention. 9 is a perspective view of the resin case used in the transformer device according to the embodiment of the present invention as viewed from above, FIG. 10 is a perspective view of the resin case as viewed from below, and FIG. 11 is A of the resin case. -A sectional view. The transformer device according to the embodiment of the present invention will be described with reference to these figures as appropriate.

In the transformer device 1 of the embodiment of the present invention, the coil component 10 is formed in the inner space of the resin case 200 surrounded by the base 210, the three wall portions 220, 230, 231 and the top plate portion 240, and the opening surface. Is housed horizontally and fixed with an adhesive (not shown). A silicone-based adhesive can be used, and the silicone-based adhesive is preferable because it has a soft hardness and a wide operating temperature range. As shown in FIG. 7, the coil component 10 has three windings M1, M2, and M3 composed of a first lead wire 20, a second lead wire 21, and a third lead wire 22 wound directly around the annular magnetic core 15. are doing. As shown in FIG. 8, three conductors 20, 21, and 22 are spirally wound around the annular magnetic core 15 by a trifilar winding without using a bobbin, and the first conductor 20 constitutes the primary winding M1. The second lead wire 21 and the third lead wire 22 form the secondary windings M2 and M3.

In the illustrated example, the first lead wire 20, the second lead wire 21, and the third lead wire 22 are marked in advance with different color tones so that they can be easily distinguished. Note that in FIG. 7, S indicates the end side at the beginning of winding of the lead wire, and E indicates the end side at the end of winding, which are assigned to each of the first to third conductors in the equivalent circuit of FIG. The black circle indicates the winding start side of the winding. If you use a marker such as an oil-based pen, you can easily color the lead wire. It is also preferable to make it easy to distinguish the end portion on the S side at the start of winding and the end on the E side at the end of winding by making the position, length, or pattern of coloring different. Further, the color tone of the insulating coating may be different for each of the conducting wires. To prevent erroneous wiring, peel off a part of the insulation coating on the end side, leaving the marking at the end of each lead wire, and entangle it with the corresponding metal terminal of the resin case and fix it with solder, referring to the marking. Is preferable.

In the coil component 10, since the lead wire is a trifilar winding, the second lead wire 21 and the third lead wire 22 are located side by side with the first lead wire 20 and next to the first lead wire 20, so that between the primary winding and the secondary winding. There is little bias between the wires of the parasitic capacitance that occurs in the above, and the connection between the winding M1 of the first wire that is the primary winding and the winding M2 of the second wire that is the secondary winding, and the winding of the first wire The difference between the connection between M1 and the winding M3 of the third conducting wire to be the secondary winding can be reduced. Further, since the first lead wire 20 can be provided between the second lead wire 21 and the third lead wire 22 to provide a gap, the parasitic capacitance between the secondary windings of the second lead wire 21 and the third lead wire 22 is reduced. It is possible to suppress the increase in insertion loss in the high frequency band.

As the first conductor 20, the second conductor 21, and the third conductor 22, a coated wire having an insulating coating on a conductor made of a conductive material such as copper, aluminum, or an alloy thereof is used. Generally, an enamel wire in which a copper wire is insulated and coated with polyamideimide is used, but considering the insulation between the primary winding and the secondary winding, a plurality of layers of insulating coatings are formed to improve the insulating property. It is preferable to use a two-layer insulated wire or a three-layer insulated wire which is a reinforced insulated wire.

The annular magnetic core 15, the resistivity ρ uses magnetic material NiZn ferrite exceeding 10 ⁵ Ω · m. The long in NiZn ferrite, without providing a magnetic gap to an annular magnetic core 15 available in a high frequency band (typically frequencies 1MHz~ tens MHz to), also 10 ⁷ times 10 ⁵ compared to MnZn ferrite It has high electrical resistance and excellent insulation, and it is easy to take measures to insulate the annular magnetic core 15 and the conductors 20, 21 and 22 without using a bobbin, and the primary and secondary windings are trifilar-wound. There is also an advantage that the coil parts can be easily miniaturized and the cost can be reduced at the same time. In the illustrated example of the annular magnetic core 15, the upper surface 18 and the lower surface facing the upper surface (not shown), and the outer peripheral surface 16 and the inner peripheral surface 17 connecting them are cylindrical, but the outer shape is a rectangular annular shape. Is also good.

The resin case 200 shown in FIGS. 9 to 11 includes a rectangular base 210 made of an insulating resin and metal terminals 110 (T1 to T8) provided on the base 210, and further has three edges of the base 210. The wall portions 220, 230, 231 erected from the above, the top plate portion 240 facing the base portion 210 and covering the upper end side of the wall portions 220, 230, 231, and the metal provided on the facing side surface side of the base portion 210. It is provided with terminals 110 (T1 to T8). The resin case 200 has a box-like shape having an opening surface on one side in the y direction in which the metal terminals 110 (T1 to T4) are formed, and the end of the metal terminal 110 is the lower surface 211b of the base 210 in the z direction. It is formed to be substantially the same as or slightly lower (protruding from the lower surface 211b).

At least the height of the wall portions 230 and 231 is formed higher than the height of the coil component described above when viewed in the z direction, and the inner space surrounded by the base portion 210, the wall portions 220, 230, 231 and the top plate portion 240. The coil parts described above can be accommodated in the coil parts, and it is possible to prevent an external force from directly acting on the coil parts. Further, it is possible to prevent the coil parts from falling off from the resin case 200, and to prevent changes in the electrical characteristics due to the disorder of the winding state of the conducting wire. Further, the top plate portion 240 is provided with a slit-shaped opening 245 on the wall portion 220 side, which is wide enough to lead out the lead wire of the coil component and is opened between the facing wall portions 230 and 231. Further, each of the wall portions 230 and 231 is provided with a protruding portion 235 formed from the top plate portion 240 to the middle of the wall portion 220 in the height direction, with a part protruding toward the wall portion 220 side. The coil parts can be accommodated in the inner space of the resin case from the opening surface of the resin case.

When viewed from below, the lower surface 211b of the base 210 faces the upper surface 211a on which the coil components are arranged, and the resin case 200 is substantially flat as a whole. The vertical relationship in the Z-axis direction will be described with reference to FIG. 9, but the vertical relationship may be described together with reference to FIG. 10 for easy understanding. On the metal terminal 110 (T1 to T4) side, protrusions 260 are formed at four positions separated from the lower surface 211b via the step portion 270. A metal terminal 110 is provided on each protrusion 260, and the lower end (upper end in FIG. 10) of each protrusion 260 is formed to be substantially the same as or slightly lower than the lower surface 211b of the base 210 (lower than the lower surface 211b). The shape of the portion of each protrusion 260 protruding from the step portion 270 is a semicircle. Further, a groove 250 is formed between the protrusions 260 in the y direction from the end of the base 210. The groove portion 250 is formed from the upper surface 211a to the lower surface 211b of the base portion 210, and is formed up to a position between the protrusion portion 260 and the step portion 270 in the y direction. In the illustrated example, a groove 250 is also formed between the metal terminal 110 (T1) and the wall portion 231 and between the metal terminal 110 (T4) and the wall portion 230.

The tips of the metal terminals 110 (T1 to T8) embedded in the two facing surfaces are projected. The metal terminals 110 (T1 to T8) can be mounted directly on the circuit board. In the illustrated example, the metal terminal 110 that is not connected to the lead wire of the coil component 10 is provided. As a result, the connection strength with the mounting board can be increased, and stable mounting becomes possible. When the connection strength with the mounting board is satisfied and it is not necessary to change the terminal position or the like, it is not necessary to provide the metal terminal which is not connected to the lead wire. It is preferable to use SPCC, Kovar, which is an alloy of nickel, cobalt and iron, 42 alloy, or the like for the metal terminal 110.

Further, although the upper surface 211a of the base 210 on which the coil component 10 is placed is a flat surface, a recess may be provided for positioning the coil component 10 or as an adhesive reservoir for fixing.

The insulating resin constituting the resin case 200 may be any resin having insulating properties, mechanical strength, chemical resistance, heat resistance, moisture resistance and moldability, and is a PPS (Poly Phenylene Sulfide) resin or a liquid crystal polymer. , PET (Polytylene Terephthelate) resin, PBT (Poly Butylene Terephthelate) resin, ABS (Acrylontile butadiene style) resin, ABS (Acrylontile butadiene style) resin, etc. Can be used.

As shown in FIGS. 1 to 5, the coil component 10 is horizontally arranged and adhesively fixed so that the upper surface 211a of the base 210 of the resin case 200 and the lower surface side of the annular magnetic core 15 face each other.

Each end of the first lead wire 20, which is the primary winding of the coil component 10, is pulled out through the groove 250. Taking one protrusion as an example, the end 20E of the first lead wire 20 is pulled out to the lower surface 211b side of the base 210 through the groove 250a of the resin case 200, and the protrusion 260 is wound through the step 270. It is led out toward the metal terminal 110 through a part of the groove 250b along the curved surface toward the other groove 250b, and is entwined and fixed. The end portion 20S of the first lead wire 20 is also led out to another metal terminal 110 in the same procedure and entwined and fixed. In each of the metal terminals 110, the entanglement fixing portion is the lower surface of the base 210 so that the surface mountability of the transformer device is not hindered even if the entanglement state of the end of the lead wire of the entanglement fixing portion varies. It is formed at a position higher in the z direction than 211b. Further, the first lead wire 20 is prevented from protruding outward from the lower surface 211b of the resin case 200 by the groove portion 250 and the step portion 270. Therefore, the transformer device is not larger than the outer shape of the resin case 200, and the flatness on the mounting surface side facing the mounting substrate is ensured and the surface mounting property is not hindered. Further, the protrusion 260 makes it easy to connect the lead wire to the terminal, which is preferable.

The ends 21S and 21E of the second lead wire 21 and the ends 22S and 22E of the third lead wire 22 are passed through the slit-shaped opening 245 on the upper side of the resin case 200 and are passed from the top plate portion 240 of the resin case 200. It is led out toward the metal terminals 110 (T5 to T8) along the wall portion 220 between the protruding portions 235 formed halfway in the height direction of the wall portion 220, and is entwined and fixed. The protruding portion 235 is formed so that the second lead wire 21 and the third lead wire 22 protrude in the y direction to the extent that they do not protrude outward, and it is possible to suppress the problem of disconnection due to the action of an external force on the lead wires. .. Further, since the second lead wire 21 and the third lead wire 22 have a longer length to the metal terminal 110 than the first lead wire 20, the second lead wire 21 and the third lead wire 22 vibrate in the resin case 200 after the transformer device is manufactured. Adhesive fixing is performed so that the lead wire does not move on the upper end side of the wall portion 220 in the z direction so as not to interfere with and rub against the wall portion 220 and damage the insulating film.

The ends of the conductors 20, 21, and 22 of the coil component 10 are appropriately pulled out and connected to the metal terminal 110 of the resin case 200. The end of the first lead wire 20 of the coil component 10 is connected to the metal terminals T2 and T3 on the first side surface side of the resin case 200, and the second lead wire 21 is connected to the metal terminals T5, T6, T7 and T8 on the second side surface side. The ends of the third lead wire 22 are connected. On the first side surface side, the winding start end 20S of the first lead wire 20 is connected to the metal terminal T2, and the winding end end 20E is connected to the metal terminal T3. On the second side surface side, the winding start end 21S of the second lead wire 21 is connected to the metal terminal T8, the winding end end 21E is connected to the metal terminal T6, and the winding start end 22S of the third lead wire 22 is a metal terminal. It is connected to T7, and the end end portion 22E is connected to the metal terminal T5. As a result, the metal terminals T8 and T7 to which the winding start end 21S of the second lead wire 21 and the winding start end 22S of the third lead wire 22 are connected are adjacent to each other, and the winding end end 21E and the third lead wire 22 of the second lead wire 21 are adjacent to each other. The metal terminals T6 and T5 to which the winding end end 22E is connected are adjacent to each other, and the metal terminals T6 and T7 to which the winding end end 21E of the second lead wire 21 and the winding start end 22S of the third lead wire 22 are connected are adjacent to each other. It becomes the transformer device 1. According to such a configuration, as shown in the equivalent circuit diagram of the transformer device, the second lead wire 21 and the third lead wire 22 constituting the secondary winding are in a state of individual windings M2 and M3 which are not connected. ing. Therefore, by changing the connection relationship with the circuit board side on which the transformer device 1 is mounted, it is possible to change the polar relationship between the windings M1, M2, and M3 as needed.

As described above, the wall portion 220 of the resin case 200 is interposed between the metal terminal 110 (T5 to T8) on the high voltage side to which the end of the secondary winding is connected and the annular magnetic core of the coil component 10. Since the coil component 10 is arranged horizontally in the inner space of the resin case 200, the distance between the top plate portion 240 side of the resin case 200 and the annular magnetic core 15 can be increased, whereby the metal terminal 110 on the high pressure side can be increased. The insulation distance between (T5 to T8) and the annular magnetic core 15 can be lengthened, and the insulation performance can be improved. Further, by using a NiZn-based ferrite magnetic material having a large resistivity for the annular magnetic core 15, the required insulation distance can be shortened, and the height of the transformer device 1 can be reduced. That is, according to the present invention, it is possible to provide a transformer device that secures a sufficient insulation distance, has a low profile, and has a small mounting area.

Further, the transformer device 1 can be made compact by making the coil component 10 a bobbin-free configuration. In the obtained transformer device 1, surface mounting is easy, external force can be prevented from directly acting on the coil component 10, and the end of the conducting wire can be protected by the resin case 200, so that external force can be obtained. It is possible to avoid problems such as disconnection of the lead wire.

1 Transformer device 10 Coil component 15 Circular magnetic core 20 1st lead wire 21 2nd lead wire 22 3rd lead wire 110 Metal terminal 200 Resin case

Claims (4)

A transformer device including a coil component in which a primary winding and a secondary winding are formed in a magnetic core, and a resin case for accommodating the coil component.
In the coil component, three conductors are spirally wound around an annular magnetic core made of NiZn-based ferrite by a trifilar winding, one of the three conductors is a primary winding, and the remaining two are two. Next winding
The resin case has a hexahedral structure, with one front surface being an opening surface and the other five surfaces being a lower base and right, left, and rear standing from the three edges of the base. It is composed of an integral resin structure consisting of three wall portions and a top plate portion at the upper end of the wall portion and facing the base portion, and a plurality of metal terminals are provided on the front and rear side surfaces of the base portion. Further, the top plate portion has a slit-shaped opening at the ridge portion on the rear wall portion side.
The coil component is adhesively fixed to the base in a horizontal state and housed in the resin case, and one lead wire for the primary winding is pulled out from the opening surface side and connected to the metal terminal on the front side. The two lead wires for the secondary winding pass through the slit-shaped opening, exceed the upper end of the rear wall portion, and are directed toward the metal terminal on the rear side along the outside of the rear wall portion. It is stretched and connected to the metal terminal,
A transformer device in which the two lead wires for the secondary winding are adhesively fixed on the upper end side of the rear wall portion. The transformer device according to claim 1.
The right wall portion and the left wall portion have a protruding portion in which a part of the top plate portion side protrudes from the rear wall portion, and the two lead wires for the secondary winding are adhesively fixed. A transformer device whose location is between the protrusion on the right wall and the protrusion on the left wall. The transformer device according to claim 1 or 2.
The NiZn ferrite transformer device resistivity ρ is 10 ⁵ Ω · m or more. The transformer device according to any one of claims 1 to 3.
A transformer device in which at least the lead wire for the secondary winding is a three-layer insulated wire among the lead wires constituting the primary winding and the secondary winding.

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