JPH073125U - Common mode choke coil parts and EMI noise filter - Google Patents

Abstract

(57) [Summary] [Purpose] To create a common mode choke coil that is significantly smaller than the conventional one and has significantly reduced leakage flux. [Structure] A flat coil 1 having a hole in the center, which is created by bundling a single self-bonding wire or a plurality of self-bonding wires and spirally winding the wire in a plane, insulating sheets 4 and 5, and a core 2 having a middle leg are combined. It is configured by putting it in a case component 6 having a terminal, connecting a lead wire from the coil to the terminal 9, and sealing the inside of the case component with a resin.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a common mode choke coil and an EMI noise filter for reducing noise used in a power input section of electronic circuits in general.

[0002]

[Prior art]

 The conventional common mode choke coil has a structure as shown in Fig. 12, and in order to insulate the coil-coil and the coil-core from each other, a collar is provided on the bobbin to secure the creepage distance.

[0003]

[Problems to be solved by the device]

 Due to this collar, the volume of the bobbin becomes large, and as a result, the occupied area and height of the entire coil become large, which is a major impediment factor in further reducing the size of the entire electronic circuit.

[0004]

[Means for Solving the Problems]

 The present invention has been made to solve the above problems, and in order to realize a thinner coil as a whole, a coil is coated with an insulating layer of a linear conductor, and a self-bonding layer is further coated thereon. A so-called self-bonding wire is bundled into a single wire or a plurality of wires, which are wound in a plane in a spiral shape to fuse wires to each other, and a flat coil having a hole in the center is used. An example of this plane coil is shown in FIGS. As shown in FIG. 5, the core used in the present invention is made of a soft magnetic material having a convex portion through which magnetic flux passes on the central portion (so-called middle leg) and the outer peripheral portion of one of the two flat plates facing each other. To use. As shown in FIG. 5, the protrusions on the outer peripheral portion are divided into a plurality of portions and are located at separate positions. Further, in the present invention, the entire coil is sealed with resin in order to reduce the size while ensuring insulation.

FIG. 1 shows an example of the configuration of the common mode choke coil according to claim 1 of the present invention. The insulating sheet 4 is bent along the middle leg and the inner wall of the core to ensure insulation between the coil and the core. This insulating sheet is produced by cutting out and bending a film-shaped resin or molding the resin using a mold having a predetermined shape. The whole assembly is performed as follows. The insulating sheet 4 is fitted into the middle leg of the core 2 and the planar coil 1 is fitted thereon. Further, another insulating sheet 4 is fitted, and the second planar coil 1 is fitted thereon so that the direction of the lead wire of the second planar coil 1 is opposite to the direction of the lead wire of the first planar coil. The flat insulating sheet 5 is sandwiched between the flat core 3 and the flat core 3. The entire assembled parts described above are put into the case part 6 and fixed by pressing with the fixing metal fitting 7. It is better to provide the case component 6 with a recess 8 as shown in FIG. 1 so that the fixing metal fitting 7 is not displaced. After the lead wire from the coil is soldered to the terminal 9 provided on the outside of the case component, a resin is cast inside the case component 6 and cured to complete the assembly. Figure 2 shows the external view after assembly is completed. In order to reduce the mounting area of the choke coil, the coil parts are erected sideways with the side of the case shown in Fig. 2 as the bottom to form a shape as shown in Fig. 6, and one terminal 11 is used only as a barb of the lead wire. Alternatively, a terminal 12 for connecting to the substrate may be separately provided at the position and a conductor 13 passing between the inside and the outside of the case may connect between them in advance. FIG. 6 is an example of an external view in this case.

Next, FIG. 7 shows an example of the configuration of the common mode choke coil according to claim 2 of the present invention. The planar coil 1, the cores 2 and 3, and the insulating sheets 4 and 5 are the same as those in claim 1, but the core is held by the base component 10 having the terminals 9. Fixing between the core and the base part is performed by pressing with the fixing metal fitting 7 as shown in Fig. 7 or fixing with an adhesive. After the lead wire from the coil is soldered to the terminal 9 and soldered, only the coil portion or the entire core, coil and base portion other than the terminal is sealed with resin to complete the assembly. FIG. 8 shows a sectional view after the assembly is completed. It is necessary to consider the flow direction of the resin and the shape of the insulating sheet so that the resin 21 is filled around the planar coil 1 without any gap.

Next, FIG. 9 shows a configuration example of the EMI noise filter according to claim 3 of the present invention. The lead wire from the coil is connected to the terminal of the case part of the common mode choke coil shown in claim 1, and other parts such as a capacitor are further connected to this terminal, and those parts are housed in the case part. The inside of the case component is sealed with resin. The equivalent circuit of FIG. 9 is as shown in FIG. 9 and 10, the across-the-line capacitor 15 is connected between both lines of the AC input, and the line bypass capacitor 16 is connected between each input line and the grounding terminal 14. Claim 3 of the present invention is not limited to the circuit of FIG. 10 as long as it is a well-known circuit that includes the common mode choke coil of claim 1 of the present invention and forms an EMI noise filter as a whole.

[0008]

[Action]

The present invention significantly reduces the thickness of common mode choke coil components by adopting a spiral flat coil with self-bonding wire and a low-profile core, and further adds coil components to the case components that have terminals for connecting the coil lead wires. By storing it and filling the inside of this case with resin, or by connecting the lead wire to the terminal of the base part and sealing the part other than the terminal with resin, the coil-core and coil-coil By eliminating the creepage distance between them, the overall occupied volume is significantly reduced. In the past, U-shaped cores were combined, but in the present invention, a low profile core having a large cross-sectional area and a small magnetic path length is used. Since the inductance of the coil is proportional to (number of turns) ² × (cross-sectional area) / (magnetic path length), in the case of the present invention, the number of turns can be made smaller than the conventional coil, and the DC resistance of the coil can be reduced. As a result of the reduction, the power loss also becomes smaller. Further, in the present invention, since the coil is housed inside the core, the magnetic flux leaking from the coil becomes significantly smaller than that of the conventional common mode choke coil component, as described later in the embodiment. This leakage magnetic flux is electromagnetically coupled with parts on the circuit of the same device and other devices and causes radiation noise. Therefore, the smaller the magnetic flux, the better. When the coil is put in a case part and sealed with resin, as described in claim 3, other parts constituting the EMI noise filter such as a capacitor are put in the case together and sealed by resin. An EMI noise filter can be incorporated in the case parts, and the mounting area on the circuit can be reduced.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. An embodiment of claim 1 is shown in FIGS. The size of the core used is 21 × 17 × 7.5H (mm), and nine 1UEW wires of 0.14φ are wound in parallel for 18T. The resin used to fill the case was a silicone rubber type with a dielectric constant of 3.3. The total size of the coil component after assembly is 26 × 24 × 8.5H (mm), the inductance is 3.0 mH, the DC resistance is 95 mΩ, and an AC current of about 2 A can flow. The dimensions of the conventional structure having the same inductance and DC resistance are those of the 3.2 mH split winding type (Fig. 12) of 27 x 24 x 38 H (mm 2) and 4.0 mH non-split winding type. It is 39 × 18 × 30 H (mm). By this consideration, the height can be reduced to about 1/4 and the mounting volume can be reduced from about 1/4 to 1/5 compared with the conventional structure. FIG. 11 shows the change in impedance in the common mode with respect to the frequency of the common mode choke coil with the specifications of 2A and 3 to 4 mH. In FIG. 11, graph a is an example, graph b is a conventional example (non-divided winding), and graph c is a conventional example (divided winding). By encapsulating with a resin, the line-to-line capacitance of the winding wire increases, but the product of the present invention exhibits an impedance extension similar to that of the conventional split winding. This is probably because the winding structure is spiral and the parasitic capacitance is small. On the other hand, the non-divided winding of the conventional structure has a large parasitic capacitance, and the impedance begins to drop in the low frequency region. The leakage flux of a common mode choke coil can be compared by measuring the inductance of one of the two coils with the other coil shorted. The measured values of the inductance at the time of this one side short for the specifications of 2 A and 3 to 4 mH described above are 5.3 μH for the product of the present invention, 88.5 μH for the divided product of the conventional structure, and 65.8 μH for the non-divided product. there were. Therefore, the leakage flux of the product of the present invention is smaller than that of the conventional structure by one digit or more, and the radiation noise is reduced accordingly. When the base part is used instead of the case part and the parts other than the terminal part are sealed as in the second aspect, the overall size is slightly smaller than that when the case part is used. When the coil and core of the specifications of 2 A and 3 mH described above were sealed with resin using the base component, the dimensions were 26 × 23 × 8.0H (mm). The electrical characteristics showed a value almost equal to that of the structure of claim 1. Regarding claim 3, for example, the size of the conventional EMI noise filter for 3A satisfying the VDE standard is 32 × 32 × 45H. (Mm), the size could be reduced to 30 × 30 × 32 H (mm) by changing to the structure of claim 3.

[0010]

[Effect of device]

 According to the common mode choke coil component of the present invention, (1) the common mode choke coil component is significantly thinned, and as a result, the electronic device can be remarkably miniaturized. (2) The leakage magnetic flux to the outside is extremely small, and the radiation noise is significantly reduced. (3) The insulation between the coils and between the coils and between the coils and the core is achieved by using an insulating sheet and resin encapsulation together to prevent accidents due to short circuits and improve the reliability of electronic devices. (4) It is easy to completely automate the winding process of the planar coil, and it is possible to completely prevent the defects of different winding numbers that often occur in the past. There are many advantages, and its industrial effect is remarkable.

[Brief description of drawings]

FIG. 1 is a configuration example of a common mode choke coil according to claim 1 of the present invention.

2 is an external perspective view (before resin sealing) of the configuration example of FIG. 1 after assembly.

FIG. 3 is a perspective view of an example of a planar coil used in the present invention.

FIG. 4 is a perspective view of another example of the planar coil used in the present invention.

FIG. 5 is a perspective view of an example of a core used in the present invention.

FIG. 6 is an external perspective view (before resin sealing) after assembly of another example of the configuration of the common mode choke coil according to claim 1 of the present invention.

FIG. 7 is a configuration example of a common mode choke coil according to claim 2 of the present invention.

8 is a sectional view of the configuration example of FIG. 6 after assembly.

FIG. 9 is a configuration example of an EMI noise filter according to claim 3 of the present invention.

FIG. 10 is an example of an equivalent circuit diagram of an EMI noise filter.

FIG. 11 is a diagram showing a change in impedance with respect to frequency in the common mode of the common mode choke coil according to claim 1 of the present invention and the conventional example.

FIG. 12 is an external front view and a bottom view of a conventional common mode choke coil by split winding.

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Claims (3)

[Scope of utility model registration request] 1. A so-called self-bonding wire in which a self-bonding wire layer which is fused to each other by heating or solvent coating is applied on an insulating layer of a conductive wire, and a so-called self-bonding wire is wound in a plane and spirally wound in a plane. Equipped with two planar coils with a hole in the center created by fusing the wires together, and these coils consist of an insulating sheet for coil-coil and coil-core insulation, and a soft magnetic material A common that is configured by putting a combination of a core into a case part having a terminal on the outside, connecting a coil lead wire to the terminal, and further sealing the inside of the case part with resin. Mode choke coil. 2. The two planar coils prepared by using a self-bonding wire, an insulating sheet for insulation between the coils and between the coils and the core, a core made of a soft magnetic material, and the core. A base part having a terminal for connecting a wire drawn from the planar coil and formed along the outer shape of the coil, and further, only the coil portion is sealed with resin, or the core and the coil and the base excluding the terminal portion are formed. A common mode choke coil characterized by being configured by sealing all parts with resin. 3. A combination of the two planar coils prepared by using self-bonding wires, an insulating sheet for insulation between the coils and between the coils and the core, and a core made of a soft magnetic material, Put this in a case part that has a connection terminal, connect the lead wire of the coil to the terminal, connect other parts such as a capacitor to this terminal and store it inside the case, then seal the entire case inside with resin. EMI noise filter configured by.