JPH1167520A - Wire wound electronic component and its sealing resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the shape of wire wound electronic components by reducing the dimensional variation of the parts and, at the same time to improve the productivity of the parts by efficiently conducting applying work and marking work. SOLUTION: After a conductor 22 is wound around a core 10, a ferrite- containing resin 54 and a conventional resin 56 are successively applied to the conductor 22. Therefore, the sealing resin of the conductor 22 has a two- layer structure of the resins 54 and 56. Since the outside layer of the sealing resin is composed of the conventional resin 56 having low viscosity and a high flow property, the sealing resin has a high leveling property after an application, and the applying work and molding work of the sealing resin can be conducted easily. In addition, the shape stability of the wire wound electronic components is improved, because the dimensional variation of the components is reduced. Moreover, the shock resistance of the outside layer of the sealing resin is improved, and marking on the outside layer is also facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wound type electronic component such as an inductor, a transformer, a choke coil and the like, and more particularly to an improvement in a sealing resin.

[0002]

2. Description of the Related Art A wound electronic component has a structure as shown in FIG. 6, for example. In the figure, square pillars (or square thick plates) are provided at both ends of a cylindrical (or elliptical, prismatic) core 10 around which a coil conductor is wound. These core 10 and tsuba 12, 14
Are made of a magnetic material such as ferrite, and these constitute a winding core (coil bobbin) 16. Electrodes 18 and 20 are formed on the outer side surfaces and end surfaces of the flanges 12 and 14, respectively.

[0003] A conductor 22 is wound around the center core 10 of the winding core 16, and lead wires 24 and 26 at both ends thereof are connected to the flange 1.
2 and 14 are joined to the electrodes 18 and 20 at the side portions, respectively. A sealing resin 28 is applied to the recess between the flanges 12 and 14 so as to cover the conductor 22. The electrodes 18, 20 to which the leads 24, 26 are connected are further plated 30, 32, respectively.

The sealing resin 28 includes, for example,
No. 2,236,305 discloses an epoxy resin containing ferrite powder. By the addition of such ferrite powder, the magnetic flux 34 passes through the sealing resin 28 to improve the magnetic shielding property, reduce the magnetic influence on adjacent components, as shown by an example with a dotted line, The inductance value of the component itself can be improved.

[0005]

However, the above background art has the following disadvantages. (1) When the ferrite powder is filled, the viscosity of the entire sealing resin increases and the fluidity decreases. For this reason, the core 16
However, there are disadvantages that it becomes difficult to apply, that the inner conductor winding portion is not impregnated, that the shape cannot be adjusted well, that dimensional variations occur and that the shape stability decreases. Further, pinholes may be formed after the resin is cured, and if moisture enters inside through the pinholes, the reliability is reduced. Further, since the viscosity increases, the core 16
The leveling property immediately after coating is poor, and it is difficult to control the amount of coating.

(2) If the content of the ferrite material in the sealing resin is increased in order to increase the inductance value, the ferrite material becomes brittle, and the impact strength of the component decreases. In addition, there is also an inconvenience that the marking on the component surface cannot be performed well. (3) If the amount of the solvent is increased to lower the viscosity, the ferrite having a high specific gravity and the resin having a low specific gravity are separated from each other, and the composition of the sealing resin becomes non-uniform. (4) When ferrite powder having a large particle size and a uniform particle size distribution is used to increase the inductance value, the fluidity under a high shear force becomes dytalability. That is, if the sealing resin after application is to be sheared at a high speed, the viscosity becomes high, and the application operation is troublesome.

The present invention focuses on the above points,
It is an object of the present invention to stabilize the shape by reducing the dimensional variation of parts and to improve productivity by performing coating and marking operations efficiently. The other purpose is
The purpose is to improve the reliability of parts, such as improving the impact strength of the exterior.

[0008]

In order to achieve the above-mentioned object, a wire-wound electronic component according to the present invention has a ferrite-containing resin applied to a conductor, and a normal resin is further applied to the ferrite-containing resin for sealing. It is characterized by the following. Another invention is characterized in that a ferrite-containing resin is applied to a core portion, a conductor is wound around the ferrite-containing resin, and a normal resin is applied thereon and sealed. Another invention is characterized in that a ferrite-containing resin is applied to a conductor, the conductor after application of the ferrite-containing resin is wound around a core, and a normal resin is applied thereon and sealed.

The sealing resin of the present invention is characterized in that a plurality of resin materials having different viscosities are mixed. Another invention is characterized in that an additive for lowering the viscosity is added to a resin material together with a powder of a ferrite material for magnetic shielding. The wire-wound electronic component of the present invention is characterized in that the conductor wound around the core is sealed with the sealing resin. The above and other objects, features, and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0010]

Embodiments of the present invention will be described below in detail. (1) Embodiment 1 First, Embodiment 1 will be described with reference to FIGS. FIG. 1 shows main manufacturing steps of the inductor element according to the first embodiment. First, as shown in FIG. 1A, a quadrangular prism-shaped core body 50 is prepared. The core body 50 is obtained by, for example, dry molding a ferrite material. A groove 5 is formed at the center of the longitudinal side of the core body 50.
2 are formed respectively. These grooves 52 are for joining the lead wires of the coil conductor.

Next, as shown in FIG.
The inside of 0 is ground into a cylindrical shape (or a polygonal shape, an elliptical shape, or the like) to form the core 10 and the flanges 12 and 14 described above. When this is fired, a core 16 is obtained. Next, as shown in FIG.
First layer electrodes 18A and 20A by dipping or the like.
To form Then, as shown in FIG. 1 (D), the conductor 22 is wound around the core 10, and the leads 24, 2
6 in the grooves 52 of the flanges 12 and 14 and the electrodes 18A and 20A
And bonded by a method such as thermocompression bonding.

Next, as shown in FIG. 1 (E), a ferrite-containing resin 54 in which a resin material is
It is applied to the concave portion of the element sandwiched between 2 and 14, and is cured. Then, as shown in FIG. 1F, a normal resin 56 made of only a resin material is applied on the ferrite-containing resin 54. Here, the ordinary resin is a resin which is not filled with a ferrite material, and is an epoxy resin, a phenol resin, an unsaturated polyester resin, a silicon resin, a polyimide resin, a polyamide resin, a polyurethane resin, a polybutylene terephthalate resin, a polyphenylene sulfide resin. ,
Polyphenylene ether resin, polyether ketone resin, liquid crystal polyester resin and the like can be used.

Usually, the resin 56 is molded and hardened in shape together with the application. Generally, the element is formed so as to have a quadrangular prism shape. Thereafter, as shown in FIG. 1G, second-layer electrodes 18B and 20B are formed at the joints between the electrodes 18A and 20A and the lead wires 24 and 26, respectively.
As shown in (H), platings 30 and 32 are applied respectively. Thus, an inductor element is manufactured. The second-layer electrodes 18B and 20B may be provided as needed, and may not be provided.

FIG. 2 shows a longitudinal section in a main step. 2A to 2C respectively correspond to FIGS. 1D to 1F. As shown in these figures in an enlarged manner, first, the conductor 2
2 is coated with a ferrite-containing resin 54, and then a normal resin 56 is applied. That is, the sealing resin has a two-layer structure of the ferrite-containing resin 54 and the normal resin 56.

As described above, according to this embodiment, since the exterior side is made of the normal resin 56, the viscosity and the viscosity are low and the flowability is high as compared with the background art using only the ferrite-containing resin. For this reason, the leveling property immediately after the application is excellent, the application operation and the molding operation can be easily performed, the dimensional variation is reduced, and the shape stability is improved. If the shape is stable,
It is also possible to bulk mount a wound electronic component. Further, the amount of the sealing resin applied can be easily controlled. In addition, the exterior strength (impact strength) is higher than that of the resin containing ferrite, and marking is easier. Furthermore, since the sealing resin has a two-layer structure, the pinholes do not communicate from the surface to the inside, preventing the invasion of moisture and improving the reliability.

(2) Embodiment 2 Next, Embodiment 2 will be described with reference to FIG. In the above embodiment, the ferrite-containing resin 54 is applied after the conductor 22 is wound, but in the present embodiment, as shown in FIG. 3A, the ferrite-containing resin 54 is applied before the conductor is wound. Then, as shown in FIG. 3B, the conductor 22 is wound over the ferrite-containing resin 54. Therefore, the ferrite-containing resin 54 is impregnated into the gap between the conductor 22 and the core 10. Thereafter, as shown in FIG. 3C, a normal resin 56 is laminated and applied.

In the second embodiment, the same effect as in the first embodiment can be obtained. In particular, ferrite-containing resin 5
Since 4 is densely impregnated into the gap between the conductor 22 and the core 10, the magnetic permeability in that portion is increased, the magnetic flux is easily passed, and the inductance value is improved.

(3) Embodiment 3 Next, Embodiment 3 will be described with reference to FIG. In this embodiment, as shown in FIG. 4A, a ferrite-containing resin 54 is applied to the conductor 22 before the conductor is wound. This work is performed by, for example, winding the ferrite-containing resin 54
It is performed by applying the paint while dripping. The conductor 22 after application is wound around the core 10 as shown in FIG. Therefore, also in the present embodiment, the ferrite-containing resin 54 is impregnated up to the gap between the conductor 22 and the core 10, as in the second embodiment. Thereafter, as shown in FIG. 4C, a normal resin 56 is laminated and applied. In the third embodiment, the same effect as in the second embodiment can be obtained.

(4) Embodiment 4 Next, Embodiment 4 will be described with reference to FIG. In the above embodiment, the sealing resin is coated in two layers, but in this embodiment 4, a single layer is formed by mixing resin materials having different molecular weights as a plurality of resin materials having different viscosities.
That is, in the present embodiment, the sealing resin is made of ferrite powder, a coupling agent, a high molecular epoxy, and a low molecular epoxy. As the polymer epoxy, for example, the epoxy equivalent (equivalent per epoxy group) is 160 to 250.
As the low-molecular epoxy, about 80 to 150 epoxy equivalents are used, for example. First, a polymer epoxy and a ferrite powder are combined and mixed with a coupling agent. Then, a low molecular weight epoxy is further mixed therein to obtain the sealing resin of the present embodiment. This sealing resin is applied one layer so as to cover the conductor 22 wound around the core 10.

In the sealing resin of the present embodiment, first, the separation or settling of the ferrite powder as an additive is suppressed by the polymer epoxy having a relatively high viscosity. In addition, the coupling agent allows the ferrite powder and the resin material (particularly, polymer epoxy) to be familiar, and the wettability of the ferrite particles to the resin material is improved. Further, the low-molecular epoxy having a relatively low viscosity allows the sealing resin to have a low viscosity as a whole, and good fluidity can be obtained. For this reason, a good shape can be obtained without having to apply twice as in the first to third embodiments.

Examples of this embodiment are as follows. For example, a coupling agent of "glycidoxypropyltrimethoxysilane", a high molecular epoxy of "bisphenol A" having a molecular weight of about 400, and a low molecular epoxy of "bisphenol""A" having a molecular weight of about 300 or "diglycidyl ether" is used. Then, they are converted into ferrite powder: coupling agent:
High-molecular epoxy: Low-molecular epoxy = 70.0: 0.7: 20.0:
Mix in the ratio of 9.3.

(5) Embodiment 5 Next, Embodiment 5 will be described with reference to FIG. This form is also an example of a single-layered sealing resin, and as shown in the figure, a low boiling solvent that evaporates at a low temperature is further added to a resin material filled with ferrite powder. By adding such a low boiling point solvent, drying of the sealing resin can be controlled, and further, the viscosity can be reduced.

If the boiling point of the solvent is high, there are disadvantages that it takes a long time to dry the sealing resin and that the drying temperature must be increased. However, when the boiling point is too low, there are disadvantages such as a short pot life at room temperature due to rapid evaporation and an increase in viscosity with the passage of time. From such a point, the evaporation temperature is preferably 150 ° C. or lower, and more preferably in the range of 100 to 150 ° C. Examples of the low boiling point solvent include methyl cellosolve.

(6) Embodiment 6 Next, Embodiment 6 will be described with reference to FIG. This embodiment is also an example of a single-layered sealing resin, and as shown in the figure, is obtained by adding spherical particles such as silica to a resin material filled with ferrite powder. When the spherical particles are added, the spherical particles are uniformly dispersed in the resin, so that the aggregation of the ferrite powder is prevented. For this reason, the fluidity of the sealing resin is improved. Further, for the same reason, the above-mentioned dytalability is also improved, and the viscosity when the sealing resin is sheared at a high speed is reduced. Accordingly, the labor required for coating is improved, and workability and productivity are improved. The diameter of the spherical particles is, for example, 2 to 12 μm (preferably 2 to 12 μm).
-5 μm), and the particle size distribution is, for example, 0.1-100 μm (preferably 0.1-30 μm).

There are many embodiments of the present invention, and various modifications can be made based on the above disclosure.
For example, the following is also included. (1) As the resin material, for example, an epoxy resin is suitable, but of course, another resin may be used. For example, a thermosetting resin other than an epoxy resin or a thermoplastic resin may be used. The same applies to the other materials described above.

(2) The structure of the wire-wound electronic component shown in FIG. 1 is merely an example, and can be applied to various structures. For example, the present invention can be applied to a winding component having a vertical structure as disclosed in Japanese Patent Application Laid-Open No. 4-338613. Others
The present invention is also applicable to winding components such as a common mode choke coil in which a core is wound by bifilar winding.

(3) The above embodiments may be combined. For example, the configuration shown in FIGS.
For example, it is applied to the embodiment shown in FIG.

[0028]

As described above, the present invention has the following effects. (1) Since the sealing resin has a multilayer structure of a ferrite-containing resin and a normal resin, the shape is stable and the dimensional variation of the parts can be reduced. In addition, it is possible to efficiently perform a sealing resin application operation and a marking operation to improve productivity. Further, the impact strength of the exterior is improved, and the influence of the pinhole is prevented, so that the reliability of the component is improved.

(2) Since two kinds of resin materials having different viscosities are mixed as a resin material, or an additive for lowering the viscosity is mixed therein, the flowability of the sealing resin is improved, and the size of the sealing resin is similarly increased. Variation is reduced, and the stability of the component shape is improved.

[Brief description of the drawings]

FIG. 1 is a view showing a process of Embodiment 1 of the present invention.

FIG. 2 is a view showing a longitudinal section of a part in a main step of the first embodiment.

FIG. 3 is a view showing a longitudinal section of a component in a main process of a second embodiment.

FIG. 4 is a view showing a longitudinal section of a part in a main step of a third embodiment.

FIG. 5 is a diagram showing a composition of a sealing resin in Embodiments 4 to 6.

FIG. 6 is a diagram illustrating an example of a wound electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Core 12, 14 ... Flange 16 ... Winding core 18, 20, 18A, 18B, 20A, 20B ... Electrode 22 ... Conductor 24, 26 ... Lead wire 28 ... Sealing resin 30, 32 ... Plating 50 ... Core element 52 ... Groove 54 ... Ferrite-containing resin 56 ... Normal resin

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01F 37/00 H01F 37/00 N 1/37 (72) Inventor Yoshihiro Amada 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Invitation (72) Inventor Hiroshi Chino 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Electric Co., Ltd. (72) Inventor Hiroshi Hagino 6-16-20, Ueno, Taito-ku, Tokyo In company

Claims (6)

[Claims] 1. A wire-wound electronic component having a conductor wound around a core, wherein a ferrite-containing resin is applied to the conductor, and the ferrite-containing resin is further coated with a normal resin and sealed. Wire-wound electronic components. 2. A wound electronic component having a core for winding a conductor, wherein a ferrite-containing resin is applied to the core portion,
A wire-wound electronic component, wherein the conductor is wound around the ferrite-containing resin, and a normal resin is applied thereon and sealed. 3. A wire-wound electronic component having a core for winding a conductor, wherein a ferrite-containing resin is applied to the conductor, and the conductor after application of the ferrite-containing resin is wound around the core. A winding type electronic component characterized by being coated with a resin and sealed. 4. A sealing resin for electronic parts, wherein a plurality of resin materials having different viscosities are mixed. 5. An encapsulating resin for electronic parts, wherein an additive for lowering the viscosity is added to a resin material together with a ferrite material powder for magnetic shielding. 6. A wound type electronic component, wherein a conductor wound around a core is sealed with the sealing resin according to claim 4.