JP7027843B2 - Manufacturing method of inductor element - Google Patents

Description

The present invention relates to a method for manufacturing an inductor element.

As an example of an inductor element, an inductor element in which a coil is embedded inside a core obtained by adding a resin to a metallic magnetic powder and pressure-molding is known.

In recent years, the current of coil components has been increasing, and it is required to improve the DC superimposition characteristics of the coil. In order to improve the DC superimposition characteristics, it is required to increase the density.

In Patent Document 1 below, a magnetic powder and a thermosetting resin are mixed and pressure-molded to form two green compacts, which are repressurized so as to sandwich the coil portion with the green compacts. It also describes a method of manufacturing a coil component that is thermoset. Then, those green compacts are provided with a strong hardness portion having a hardness at which the shape of the green compact does not collapse during repressurization molding and a weak hardness portion having a hardness at which the shape of the green compact does not collapse, and the weak hardness portion is formed by recompression. Molding is performed while breaking down.

However, since the shape of the weak hardness portion tends to collapse during repressurization molding, sufficient pressure transmission cannot be performed, and in particular, the density of the portion where the green compacts are bonded tends to be low. That is, in the finally obtained inductor element, the density unevenness of the core tends to occur. As a result, the DC superimposition characteristic tends to be deteriorated.

Furthermore, if an attempt is made to increase the pressure during repressurization in order to increase the density, the coil coating may be torn or the inner wall of the mold may rub against the surface of the magnetic powder, which tends to reduce the withstand voltage. ..

Japanese Patent Application Laid-Open No. 2002-252120

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing an inductor element having excellent withstand voltage, inductance, DC superimposition characteristics and molded body bending strength.

In order to achieve the above object, the method for manufacturing an inductor element according to the present invention is:
The process of preparing an insert member having a winding part in which a conductor is wound in a coil shape, and
The process of pre-compressing granules containing magnetic powder and thermosetting resin to obtain a plurality of preformed bodies, and
A step of mainly compressing the insert member and the plurality of preformed bodies at a temperature equal to or higher than the softening point and lower than the curing start temperature to obtain an integrated molded body.
After the step of obtaining the integrated molded body, a step of main heating the integrated molded body to a temperature higher than the curing start temperature of the thermosetting resin to obtain an inductor element.
Have.

The inductor element manufactured by the above manufacturing method is excellent in withstand voltage, inductance, DC superimposition characteristics and molded body breaking load.

The step of obtaining the integrated molded body may be performed by arranging the insert member and the plurality of preformed bodies in the cavity of the mold and performing main compression.

The plurality of preformed bodies may be preheated before being placed in the mold.

The insert member may be preheated before being placed in the mold.

In the step of obtaining the integrated molded body, the magnetic powder and the thermosetting resin may be inserted into the gap between the conductor in the winding portion and the preformed body.

The granules containing the magnetic powder and the thermosetting resin may be preformed by precompression molding at a pressure of 2.5 × 10 ² to 1 × 10 ³ MPa to obtain a plurality of preformed bodies.

The pressure at the time of the main compression may be equal to or less than the pressure at the time of the precompression molding.

FIG. 1 is a cross-sectional view of an inductor element manufactured by the method for manufacturing an inductor element according to an embodiment of the present invention. FIG. 2 is a perspective view showing a preformed body and an insert member used in the process of manufacturing the inductor element shown in FIG. 1. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. FIG. 4 is a cross-sectional view showing an inductor element manufactured by the method for manufacturing an inductor element according to another embodiment of the present invention. FIG. 5 is a perspective view showing a preformed body and an insert member used in the process of manufacturing the inductor element shown in FIG. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. FIG. 7 is a cross-sectional view showing an inductor element manufactured by the method for manufacturing an inductor element according to another embodiment of the present invention. FIG. 8 is a perspective view showing a preformed body and an insert member used in the process of manufacturing the inductor element shown in FIG. 7. FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. FIG. 10 is a cross-sectional view showing an inductor element manufactured by the method for manufacturing an inductor element according to another embodiment of the present invention. FIG. 11 is a perspective view showing a preformed body and an insert member used in the process of manufacturing the inductor element shown in FIG. FIG. 12 is a cross-sectional view taken along the line XII-XII of FIG. FIG. 13A is a flow chart showing a manufacturing process according to an embodiment of the present invention. FIG. 13B is a flow chart showing a manufacturing process of a comparative example of the present invention. FIG. 14 is a graph showing the characteristics of Examples and Comparative Examples of the present invention. FIG. 15 is a graph showing the characteristics of Examples and Comparative Examples of the present invention.

Hereinafter, the present invention will be described based on the embodiments shown in the drawings, but the present invention is not limited to the following embodiments.

First Embodiment As shown in FIG. 1, the inductor element 2 manufactured by the method for manufacturing an inductor element according to the embodiment of the present invention has a winding portion 4 and a core portion 6. In the winding portion 4, the conductor 5 is wound in a coil shape. The core portion 6 has an inner peripheral portion (also referred to as a core portion) 6a located on the inner peripheral side of the winding portion 4 and an outer peripheral portion 6b located on the outer peripheral side of the winding portion 4. The magnetic powder and the thermosetting resin constituting the core portion 6 are contained in the gap portion 6c between the conductor 5 constituting the winding portion 4 and the core portion 6.

In the inductor element 2 of the present embodiment, the upper surface and the lower surface of the core portion 6 are substantially perpendicular to the Z axis, and the side surfaces of the core portion 6 are substantially perpendicular to the plane including the X axis and the Y axis. There is. Further, the winding axis of the winding portion 4 is substantially parallel to the Z axis. However, the shape of the core portion 6 is not limited to the shape shown in FIG. 1, and may be a cylindrical shape, an elliptical pillar, or the like.

The size of the inductor element 2 of the present embodiment is not particularly limited, but for example, the portion excluding the lead portions 5a and 5b is a rectangular parallelepiped having a size of (2 to 17) mm × (2 to 17) mm × (1 to 7) mm. Or the size included in the cube. In FIG. 1, the lead portions 5a and 5b of the winding portion 4 shown in FIG. 2 are not shown. The lead portions 5a and 5b formed at both ends of the conductor 4 constituting the winding portion 4 are taken out to the outside of the core portion 6 shown in FIG.

The outer periphery of the conductor (conductor) 5 constituting the winding portion 4 is coated with an insulating coating layer, if necessary. The conductor 5 is made of, for example, Cu, Al, Fe, Ag, Au, or an alloy containing these metals. The insulating coating layer is composed of, for example, polyurethane, polyamide-imide, polyimide, polyester, polyester-imide, polyester-nylon and the like. The cross-sectional shape of the conductor 5 is not particularly limited, and examples thereof include a circular shape and a flat shape. In the present embodiment, the cross-sectional shape of the conductor 5 is circular.

The core portion 6 has a magnetic powder and a thermosetting resin (binder). The material of the magnetic powder is not particularly limited, but ferrite such as Mn-Zn and Ni-Cu-Zn, Fe-Si (iron-silicon), sendust (Fe-Si-Al; iron-silicon-aluminum), and the like. Examples of metals include Fe-Si-Cr (iron-silicon-chromium) and permalloy (Fe-Ni). The crystal structure of the magnetic powder is not particularly limited, and amorphous, crystalline and the like are exemplified.

The type of the thermosetting resin is not particularly limited, and examples thereof include an epoxy resin, a diallyl phthalate resin, a phenol resin, a polyimide, a polyamide-imide, and a silicon resin, and a combination thereof.

The softening point of the thermosetting resin is preferably 50 ° C to 100 ° C. This makes it possible to obtain a preformed body having a sufficiently high density. From the above viewpoint, the softening point of the thermosetting resin is more preferably 60 ° C. to 90 ° C. By molding the preformed body to be molded at room temperature below the softening point, it is possible to suppress the adhesion of the mold due to stickiness or the like. From this point of view, it is desirable that the softening point is at room temperature or higher.

The curing start temperature of the thermosetting resin is preferably 100 ° C to 250 ° C. As a result, it is possible to achieve high heat resistance that can withstand reflow or the like that increases the crosslink density of the resin by optimizing the curing start temperature. From the above viewpoint, the curing start temperature of the thermosetting resin is more preferably 150 ° C. to 220 ° C.

In particular, the softening temperature and the curing start temperature are not limited, but if the difference between the softening temperature and the curing start temperature is small, when the temperature variation during the main pressurization occurs, the crimping state and the characteristic variation of the integrated molded body are likely to occur. Therefore, it is desirable that the difference between the softening temperature and the curing start temperature is 5 ° C. or more.

The molecular weight of the thermosetting resin is usually about 300 to 10,000 by weight average molecular weight Mw. The above thermosetting resin may be used alone or may use a plurality of types of resins. Further, a compound having a structure in which different types of thermosetting resins are crosslinked may be used.

Next, the method of manufacturing the inductor element 2 shown in FIG. 1 will be described with reference to FIGS. 2 and 3.

The inductor element 2 manufactured by the method for manufacturing an inductor element according to the embodiment of the present invention comprises two preformed bodies 60a and 60b and an insert member having a winding portion 4 composed of an air core coil or the like. Manufactured by integrating. Both ends of the conductor 5 constituting the winding portion 4 are drawn out to the outside of the winding portion 4 as lead portions 5a and 5b. The terminals (not shown) may be connected to the lead portions 5a and 5b after the main compression, or may be connected in advance before the main compression.

Planned joining surfaces 70a and 70b are formed on the preformed bodies 60a and 60b, respectively, and they are butted against each other and joined to form an intermittent joining interface 7 shown in FIG. The planned joining surfaces 70a and 70b are formed with accommodating recesses 90a and 90b for accommodating the upper half and the lower half of the winding portion 4, respectively. The size of the accommodating recesses 90a and 90b is such that the winding portion 4 as an insert member can be inserted into the winding portion 4 in contact with the inner peripheral periphery thereof and the end portion in the winding axis direction.

Further, a drawer groove 80 for pulling out the lead portions 5a and 5b to the outside of the core portion 6 is formed on either one or both of the planned joining surfaces 70a and 70b. Although the pair of lead portions 5a and 5b are shown in FIG. 2, the pair of lead portions 5a and 5b are omitted in FIG.

First, granules used as raw materials for the preformed bodies 60a and 60b are produced. There are no particular restrictions on the method for producing granules. For example, it can be produced by adding a thermosetting resin to a magnetic powder, stirring it, and then drying it.

The particle size of the magnetic powder is not particularly limited, but for example, a magnetic powder having an average particle size of 0.5 to 50 μm can be used. The resin is not particularly limited, and examples thereof include epoxy resin, diallyl phthalate resin, phenol resin, polyimide, polyamide-imide, silicon resin, and a combination thereof. Further, an insulating film may be formed on the surface of the magnetic powder before the magnetic powder and the thermosetting resin are mixed. For example, an insulating film which is a SiO ₂ film can be formed by the sol-gel method.

Further, coarse granules may be removed by adding a thermosetting resin to the magnetic powder, stirring the mixture, and then passing the mixture through a mesh. Further, the thermosetting resin may be diluted with a solvent when it is added to the magnetic powder. As the solvent, for example, ketones and the like are used.

The content of the thermosetting resin is not particularly limited, but it is preferably 1.0 to 6.0 wt% with respect to 100 wt% of the magnetic powder. By setting the content of the thermosetting resin to an appropriate amount, it becomes easy to join the planned joining surfaces 70a and 70b at the time of the main compression described later.

The preformed bodies 60a and 60b are manufactured by filling the cavities of the first mold with the granules containing the magnetic powder and the thermosetting resin and pre-compressing them. The pressure during precompression molding is 2.5 × 10 ² to 1 × 10 ³ MPa (2.5 to 10 t / cm ² ). The densities of the preformed bodies 60a and 60b are not particularly limited, but are, for example, 4.0 to 6.5 g / cm ³ . By setting the pressure during precompression molding to 2.5 × 10 ² to 1 × 10 ³ MPa, distortion of the position of the winding portion 4 and / or distortion of the shape of the winding caused after the main compression described later is prevented. It is possible to manufacture an inductor element having excellent withstand voltage, inductance and DC superimposition characteristics.

The temperature at the time of precompression molding is not particularly limited, and is performed at a temperature near room temperature.

Next, the obtained preformed bodies 60a and 60b and the insert member are arranged in the cavity of the second mold different from that at the time of manufacturing the preformed body in the embodiment shown in FIGS. 2 and 3, and the thermosetting resin is placed. An integrated molded product can be obtained by performing the main compression (crimping) at a temperature equal to or higher than the softening point and lower than the curing start temperature.

The preformed body and the insert member are preheated before the preformed body and the insert member are arranged in the cavity of the second mold, or after the preformed body and the insert member are arranged in the cavity of the second mold. You may. In particular, by preheating the preformed body and the insert member before placing the preformed body and the insert member in the cavity of the second mold, the preformed body and the insert member are placed in the second mold and then the preformed body and the insert member are placed. Since the time for raising to a predetermined temperature can be shortened, productivity is improved.

It should be noted that only the preformed body may be preheated before being placed in the second mold, and the insert member may be preheated after being placed in the second mold. Further, only the insert member may be preheated before being placed in the second mold, and the preformed body may be preheated after being placed in the second mold.

The temperature of this compression is preferably 2 ° C. or higher than the softening point of the thermosetting resin and 2 ° C. or higher lower than the curing start temperature of the thermosetting resin. This makes it possible to prevent the preformed body from being excessively heated and starting to cure. From the above viewpoint, the temperature of the preheating is more preferably 5 ° C. or higher than the softening point of the thermosetting resin and 5 ° C. or higher lower than the curing start temperature of the thermosetting resin.

The pressure at the time of this compression is not particularly limited, but is, for example, 1 × 10 ² to 8 × 10 ² MPa (1 to 8 t / cm ² ). Further, the pressure during the main compression is preferably as low as about 40 to 80%, more preferably as low as about 50 to 60%, as compared with the pressure at the time of precompression molding (100%). By lowering the pressure during the main compression, the distortion of the position of the winding portion 4 and / or the distortion of the shape of the winding caused after the main compression is prevented, and the pressure during the precompression molding is compared with the pressure during the main compression. The larger the value, the better the withstand voltage characteristics.

In the process of obtaining the integrally molded body, the magnetic powder and the thermosetting resin are impregnated into the gap between the conductor and the preformed body in the winding portion.

Next, the heat-curable resin is completely cured by performing the main heating on the integrally molded body taken out from the second mold after the main compression to obtain the inductor element 2. Specifically, the thermosetting resin is completely cured by mainly heating the integrally molded body taken out from the second mold at a temperature higher than the temperature at which the thermosetting resin starts to cure.

The temperature during the main heating is preferably 10 to 100 ° C. higher than the curing start temperature of the thermosetting resin. This makes it possible to reduce the rate of change in inductance due to deformation and heat due to reflow. From the above viewpoint, it is more preferable that the temperature at the time of the main heating is 20 to 100 ° C. higher than the curing start temperature of the thermosetting resin.

In the inductor element 2 obtained by the above manufacturing method, the preformed bodies 60a and 60b remain as they are except for the bonding interface 7, so that distortion of the position of the winding portion 4 and / or distortion of the shape of the winding is prevented. The core portion 6 can be formed at a high density. Therefore, the withstand voltage can be improved while improving the inductance and the DC superimposition characteristic. Further, at the time of main compression, by crimping at a lower pressure than at the time of precompression molding, the planned joining surfaces 70a and 70b and their vicinity are partially fluidized and mixed, and the joining interface 7 is formed.

In the present embodiment, the core portion 6 of the finally obtained inductor element 2 can be manufactured uniformly and at high density. As a result, the inductance and DC superimposition characteristics can be improved as compared with the conventional inductor element.

2nd Embodiment Hereinafter, the 2nd embodiment will be described with reference to FIGS. 4 to 6, but the points common to the 1st embodiment (common configuration and action / effect, etc./same below) will be omitted.

As shown in FIG. 4, the inductor element 2A of the second embodiment has a different position of the junction interface 7 from the inductor element 2 of the first embodiment.

As a method for manufacturing the inductor element 2A of the second embodiment, for example, as shown in FIGS. 5 and 6, there is a method of preparing a plate-shaped preformed body 60a1 and a pot-shaped preformed body 60b1. The planned joining surface 70a1 of the plate-shaped preformed body 60a1 and the planned joining surface 70b1 of the pot-shaped preformed body 60b1 are joined to intermittently form the joining interface 7 shown in FIG. Further, as the position of the bonding interface 7 changes, the positions of the lead portions 5a and 5b shown in FIG. 5 change.

3rd Embodiment Hereinafter, the 3rd embodiment will be described with reference to FIGS. 7 to 9, but the points common to the 1st embodiment and the 2nd embodiment (common configuration and action / effect, etc./same below) will be described. The explanation is omitted.

As shown in FIG. 7, in the inductor element 2B manufactured by the method for manufacturing the inductor element of the third embodiment, the number of bonding interfaces is 7a1,7a2,7b1,7b2,7c, which is larger than that of the first embodiment. Specifically, the joining interface 7a2, 7b2 is intermittently formed between the core portion 6a2 and the outer peripheral portion 6b2, and the joining interface 7a1 is intermittently formed inside the outer peripheral portion 6b2 at predetermined intervals in the Z-axis direction. , 7b1,7c are formed. The more the junction interface, the better the DC superimposition characteristics tend to be.

As a method of manufacturing the inductor element 2B of the third embodiment, for example, as shown in FIGS. 8 and 9, there is a method of preparing five preformed bodies 60c, 60d, 60e, 60f, 60g. The planned joining surface 70c of the plate-shaped preformed body 60c and the planned joining surface 70d1 of the ring-shaped preformed body 60d are joined to intermittently form the joining interface 7a1 shown in FIG. 7.

The planned joining surface 70c of the preformed body 60c shown in FIG. 8 and the planned joining surface 70d2 of the columnar preformed body 60e are joined to intermittently form the joining interface 7a2 shown in FIG. 7. The planned joining surface 70e of the ring-shaped preformed body 60d shown in FIG. 8 and the planned joining surface 70g of the ring-shaped preformed body 60f are joined to intermittently form the joining interface 7c shown in FIG. Will be done.

The planned joining surface 70f1 of the ring-shaped preformed body 60f shown in FIG. 8 and the planned joining surface 70h of the plate-shaped preformed body 60g are joined to intermittently form the joining interface 7b1 shown in FIG. To. The planned joining surface 70f2 of the cylindrical preformed body 60e shown in FIG. 8 and the planned joining surface 70h of the plate-shaped preformed body 60g are joined to intermittently form the joining interface 7b2 shown in FIG. ..

Fourth Embodiment Hereinafter, the fourth embodiment will be described with reference to FIGS. 10 to 12, but the points common to the first to third embodiments will be omitted.

As shown in FIG. 10, in the inductor element 2C manufactured by the method for manufacturing the inductor element of the fourth embodiment, the bonding interfaces 7a3 and 7b3 are intermittently formed between the core portion 6a3 and the outer peripheral portion 6b3. The bonding interface 7c3 is also intermittently formed inside the intermediate portion of the outer peripheral portion 6b3 in the Z-axis direction.

As a method of manufacturing the inductor element 2C of the fourth embodiment, for example, as shown in FIGS. 11 and 12, there is a method of preparing three preformed bodies 60e2, 60h, 60i. Then, the planned joining surface 70i and the planned joining surface 70m are joined to form the joining interface 7c3 intermittently. The planned joining surface 70j and the planned joining surface 70k are joined to form a joining interface 7a3 intermittently. The planned joining surface 70l and the planned joining surface 70n are joined to form a joining interface 7b3 intermittently.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

Example 1
In Example 1, as shown in FIG. 13A, a preformed body having the shapes shown in FIGS. 2 and 3 was produced by precompression molding, and then main compression was performed to obtain an inductor element having the shape shown in FIG. ..

First, granules to be filled in the cavity of the first mold were prepared. A Fe—Si—Cr alloy (average particle size 25 μm) was prepared as the magnetic powder, and an insulating film, which is a SiO ₂ film, was formed on the surface of the magnetic powder using the sol-gel method. Epoxy resin diluted with acetone was added to the magnetic powder in an amount of 3% by weight based on 100% by weight of the entire magnetic powder, and the mixture was stirred. After stirring, a 250 micron open mesh was passed and dried at room temperature for 24 hours to obtain granules to be filled in the cavity of the first mold.

The granules were filled in the cavity of the first mold and pre-compression molding was performed to prepare a pre-molded body having the shapes shown in FIGS. 2 and 3. The pressure at the time of precompression molding was 6 t / cm ² .

Next, the prepared premolded body and the insert member were placed in the cavity of the second mold different from the first mold used for the precompression molding. Inside the cavity, the two preformed bodies shown in FIGS. 2 and 3 and an insert member having a winding portion having an inner diameter of 4 mm and a height of 3 mm were arranged in the manner shown in FIGS. 2 and 3.

Next, the temperature of the preformed body and the insert member was set to the temperature shown in Table 1, and pressure was applied from above and below in the Z-axis direction of FIG. 3 to perform main compression to obtain an integrated molded body. The molding pressure at the time of this compression was 1.5 t / cm ² . The softening point of the epoxy resin is 95 ° C., and the curing start temperature is 110 ° C.

After that, the integrated molded body was taken out from the second mold, and the main heating was performed at 200 ° C. for 1 hour to cure the epoxy resin, and a sample (sample number 2) of the inductor element of each example shown in Table 1 was obtained. Obtained. The dimensions of the obtained core portion were 7 mm in length × 7 mm in width × 5.4 mm in height.

For the inductor element sample thus obtained, the inductance, DC superimposition characteristics, withstand voltage, and molded body fracture load were measured. The results are shown in Table 1.

The inductance was measured using an LCR meter (manufactured by Hewlett-Packard Co., Ltd.) at a measurement frequency of 100 KHz and a measurement voltage of 0.5 mV.

To measure the DC superimposition characteristics, a DC current is applied from 0 to the sample of each inductor element, and the value (ampere) of the current flowing when the current drops to 80% with respect to the inductance (μH) when the current is 0. It was designated as Idc1 and evaluated by the numerical value of Idc1.

To measure the withstand voltage, apply a voltage between the side surface of each inductor element and the opposite side surface using a KEYSIGHT DC POWER SUPPLY and an LCR meter, and use the voltage when a current of 0.5 mA flows as the withstand voltage. did.

An autograph AGS-5KNK manufactured by Shimadzu Corporation was used for measuring the fracture load of the molded body. A three-point bending test was performed with the inductor element sandwiched in the direction perpendicular to the winding axis direction. The speed of the probe to which the load was applied was set to 1 / mm. ..

Comparative Example 1
In Comparative Example 1, a sample of the inductor element (Sample No. 1) shown in Table 1 was obtained in the same manner as in Example 1 except that the temperature at the time of this compression was set to 85 ° C. The results are shown in Table 1.

Example 2
In Example 2, a sample of the inductor element (Sample No. 4) shown in Table 1 was obtained in the same manner as in Example 1 except that the thermosetting resin was changed to diallyl phthalate resin (DAP). The results are shown in Table 1. The softening point of DAP is 80 ° C., and the curing start temperature is 150 ° C.

Example 3
In Example 3, a sample of the inductor element (Sample No. 5) was obtained in the same manner as in Example 1 except that the premolded body was preheated before the preformed body was placed in the second mold. The results are shown in Table 1.

Example 4
In Example 4, a sample of the inductor element (Sample No. 6) was obtained in the same manner as in Example 1 except that the insert member was preheated before the insert member was placed in the second mold. The results are shown in Table 1.

Example 5
In Example 5, the inductor element sample (sample number) is the same as in Example 1 except that the premolded body and the insert member are preheated before the premolded body and the insert member are placed in the second mold. 7) was obtained. The results are shown in Table 1.

Comparative Example 2
In Comparative Example 2, a sample of the inductor element of Comparative Example shown in Table 1 was obtained in the same manner as in Example 1 except that the epoxy resin was cured by performing main heating at the temperature shown in Table 1 for 1 hour at the same time as the main compression. Sample number 11) was obtained. Further, a flow chart of the manufacturing process is shown in FIG. 13B. The results are shown in Table 1.

FIG. 14 shows a graph showing the relationship between the DC superimposition characteristics and the inductances of the above-mentioned Examples and Comparative Examples.

FIG. 15 shows a graph showing the relationship between the DC superimposition characteristics and the fracture load of the molded product of the above-mentioned Examples and Comparative Examples.

From Table 1, FIG. 14 and FIG. 15, the inductor elements (sample numbers 2, 4 to 7) obtained by main compression at a temperature equal to or higher than the softening point and lower than the curing start temperature to obtain an integrated molded body have softening points. In the following, it was confirmed that the withstand voltage, the inductance, the DC superimposition characteristics, and the fracture load of the molded body were better than those of the inductor element (Sample No. 1) obtained by performing the present compression to obtain the integrated molded body.

From Table 1, the inductor element (Sample Nos. 2, 4 to 7) obtained by the main heating after the main compression is compared with the inductor element (Sample No. 11) obtained by the main heating at the same time as the main compression. It was confirmed that the withstand voltage, inductance, DC superimposition characteristics and molded body breaking load were good.

2,2A, 2B, 2C ... Inductor element 4 ... Winding part 5 ... Conductor 5a, 5b ... Lead part 6,6A, 6B, 6C ... Core part 6a, 6a1, 6a2, 6a3 ... Inner peripheral part 6b, 6b1, 6b2 , 6b3 ... Outer peripheral part 6c ... Conductor gap 6d ... Intermediate position
7,7a1,7a2,7a3,7b1,7b2,7b3,7c, 7c3 ... Joining interface 60a to 60k ... Preformed body 70a to 70n ... Planned joining surface 80 ... Drawer groove 90a, 90b ... Accommodating recess

Claims (6)

The process of preparing an insert member having a winding part in which a conductor is wound in a coil shape, and
The process of pre-compressing granules containing magnetic powder and thermosetting resin to obtain a plurality of preformed bodies, and
A step of mainly compressing the insert member and the plurality of preformed bodies at a temperature equal to or higher than the softening point and lower than the curing start temperature to obtain an integrated molded body.
After the step of obtaining the integrated molded body, the integrated molded body is mainly heated to a temperature higher than the curing start temperature of the thermosetting resin to obtain an inductor element .
A method for manufacturing an inductor element in which the pressure during main compression is 40 to 80% lower than the pressure during precompression molding . The method for manufacturing an inductor element according to claim 1, wherein the step of obtaining the integrated molded body is performed by arranging the insert member and the plurality of preformed bodies in a cavity of a mold and performing main compression. The method for manufacturing an inductor element according to claim 2, wherein the plurality of preformed bodies are preheated before being placed in the mold. The method for manufacturing an inductor element according to claim 2 or 3, wherein the insert member is preheated before being placed in the mold. The manufacture of the inductor element according to any one of claims 1 to 4, wherein in the step of obtaining the integrated molded body, the magnetic powder and the thermosetting resin are allowed to enter the gap between the conductor in the winding portion and the preformed body. Method. Any of claims 1 to 5 to obtain a plurality of preformed bodies by precompressing the granules containing the magnetic powder and the thermosetting resin at a pressure of 2.5 × 10 ² to 1 × 10 ³ MPa. The method for manufacturing an inductor element according to.

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