JP2013051399A - Inductor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductor and a manufacturing method of the same, which can obtain high inductance L by optimization of a filling rate and Young's modulus of a magnetic powder, particularly.SOLUTION: An inductor comprises: a coil; a core member including a first core in which a based housing part for the coil is formed and a second core covering the opening side of the housing part; and a filler filling a clearance with the coil in a nearly enclosed space between the housing part and the second core located on the open end side of the housing part. The core member is formed by compression molding of an Fe-based amorphous alloy powder and a binding agent. The filler is composed of a resin and a magnetic powder in which a Young's modulus of the resin is not less than 0.1 GPa and not more than 3.2 GPa, and the magnetic powder is contained in the filler in a range of not less than 30 vol% and not more than 60 vol%.

Description

  In the present invention, the core member is separated into a first core having a coil storage portion and a second core as a lid, and after the coil is stored in the first core, the second core is joined to the first core. And an inductor manufacturing method thereof.

  A coil-enclosed magnetic core (inductor) 1 shown in FIG. 7 has a structure that is compression-molded in a state where a coil 3 is enclosed inside a dust core 2. For the powder core 2, an Fe-based amorphous alloy powder having excellent soft magnetic properties is preferably used. However, since the Fe-based amorphous alloy powder has a large magnetostriction, in order to achieve the original performance of the amorphous powder, the molding pressure is increased to increase the molding density, and annealing treatment is performed at a high temperature to reduce stress. It was necessary to promote. However, there is a problem that the coil wire covering material is broken or thermally decomposed. Therefore, the molding pressure and the annealing temperature are limited by the coil wire covering material.

  On the other hand, as shown in the patent document, if the core member is divided into a plurality of pieces and the coil is accommodated, unlike the coil-encapsulated magnetic core shown in FIG. 7, the restriction due to the coil wire covering material can be eliminated. The member can be molded at a high pressure and an optimum annealing temperature, and the original performance of the Fe-based amorphous alloy powder can be extracted.

  By the way, even if the gap formed between the core member and the coil is filled with resin, it becomes a gap and leads to characteristic deterioration. Therefore, the following patent document discloses a configuration in which magnetic powder is mixed and filled in the resin. Yes.

JP 60-214510 A JP 2000-182845 A JP 2008-235773 A JP 2005-175158 A JP 2008-218724 A

  However, it has been found that when the Fe-based amorphous alloy powder having a large magnetostriction is used for the core member, the inductance L decreases due to the Young's modulus of the resin. Each patent document does not particularly mention the Young's modulus of the resin.

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, to provide an inductor capable of obtaining a high inductance L by optimizing the Young's modulus together with the filling rate of magnetic powder and a method for manufacturing the same. With the goal.

An inductor according to the present invention includes a coil, a core member configured to include a first core in which a bottomed storage portion for the coil is formed, and a second core that covers an opening side of the storage portion, and the storage portion And a filler that fills a gap with the coil in a substantially enclosed space between the second core located on the open end side of the storage portion, and
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
The filler is composed of resin and magnetic powder,
The Young's modulus of the resin is 0.1 GPa or more and 3.2 GPa or less,
The magnetic powder is contained in the filler in a range of 30% by volume to 60% by volume.

The inductor manufacturing method according to the present invention includes a coil, a first core in which a bottomed storage portion for the coil is formed, and a core member configured to have a second core that covers the opening side of the storage portion; A filler that fills a gap with the coil in a substantially enclosed space between the storage part and the second core located on the open end side of the storage part,
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
A magnetic powder is mixed with a resin having a Young's modulus of 0.1 GPa or more and 3.2 GPa or less in a range of 30% by volume or more and 60% by volume or less to produce the filler.
The coil is housed in the housing portion of the first core, the filler is filled on the opening side of the housing portion, and then the second core is covered on the opening side of the first core. And the second core are joined together.

  As described above, the present invention is to fill the gap between the filler in the space substantially surrounded by the storage portion formed in the first core and the second core, and in such a configuration, In order to obtain a high inductance L, in the present invention, the content of the magnetic powder contained in the filler and the Young's modulus of the resin are defined as described above. As a result, while maintaining the fluidity of the filler appropriately, the filler can be appropriately poured between the core member and the coil, and a considerable amount of magnetic powder can be interposed in the gap between the core member and the coil. . Even when Fe-based amorphous alloy powder having a large magnetostriction is used for the core member, the internal stress of the filler itself can be reduced, and the stress acting on the core member can be reduced. As described above, the inductance L can be improved in the present invention. In particular, according to the present invention, a higher inductance L can be obtained as compared with a coil-encapsulated magnetic core formed by compression-molding a core with a coil encapsulated.

  In the present invention, the magnetic powder is preferably contained in the filler in a range of 40% by volume to 60% by volume. Thereby, the high inductance L can be obtained more effectively.

  In the present invention, the Young's modulus of the resin is preferably 0.9 GPa or more and 3.2 GPa or less. Furthermore, in the present invention, the Young's modulus of the resin is more preferably 0.9 GPa or more and 1.5 GPa or less. Thereby, the high inductance L can be obtained more effectively.

  The magnetic powder contained in the filler is preferably an Fe-based amorphous alloy powder. As a result, high soft magnetic characteristics can be secured, and a high inductance L can be obtained more effectively.

With this embodiment, the Fe-based amorphous alloy powder, the composition formula is represented by _{Fe 100-abcxyzt Ni a Sn b} Cr c P x C y B z Si t, 0at% ≦ a ≦ 10at%, 0at% ≦ b ≦ 3 at%, 0 at% ≦ c ≦ 6 at%, 6.8 at% ≦ x ≦ 10.8 at%, 2.0 at% ≦ y ≦ 9.8 at%, 0 at% ≦ z ≦ 8.0 at%, 0 at% It is preferable that the Fe-based soft magnetic alloy powder satisfy ≦ t ≦ 5.0 at%.

Alternatively, the present invention provides a coil, a core member configured to include a first core in which a bottomed storage portion for the coil is formed, and a second core that covers an opening side of the storage portion, and the storage portion. A filler that fills a gap with the coil in a substantially enclosed space between the second core located on the open end side of the storage portion;
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
The filler is composed of resin and magnetic powder,
The Young's modulus of the resin is 3.2 GPa or more and 5.2 GPa or less,
The magnetic powder is contained in the filler in a range of 40% by volume to 55% by volume.

  Also in this invention, it is possible to obtain a higher inductance L than a coil-encapsulated magnetic core formed by compression-molding a core with the coil encapsulated.

  According to the inductor and the manufacturing method thereof of the present invention, a high inductance L can be obtained.

FIG. 1 is an exploded perspective view of the inductor according to the present embodiment. FIG. 2 is a perspective view showing a state where the coil is housed in the first core shown in FIG. FIG. 3 is a perspective view of the inductor in a state in which the filler is filled from the state of FIG. 2 and the second core is covered on the first core. 4 is a longitudinal sectional view of the inductor showing a state in which the filler is filled from the state of FIG. FIG. 5 is a longitudinal sectional view of the inductor showing a state in which the second core is joined to the upper surface of the first core via a filler from the state of FIG. 4. FIG. 6A is a graph showing the relationship between the Young's modulus of the resin constituting the filler and the inductance L, and shows the first example in which the range of Young's modulus is defined as 0.1 GPa to 3.2 GPa. . FIG. 6B is a graph showing the relationship between the Young's modulus of the resin constituting the filler and the inductance L, and shows a second example in which the range of Young's modulus is defined as 3.2 GPa to 5.2 GPa. . FIG. 7 is a plan view of a coil-encapsulated magnetic core formed by compression-molding a core with a coil encapsulated.

FIG. 1 is an exploded perspective view of the inductor according to the present embodiment.
As shown in FIG. 1, the inductor 10 includes a first core (molded body) 11, a coil 12, and a second core (lid body) 13. The first core 11 and the second core 13 constitute a core member 14.

  The core member 14 is formed by compression molding an Fe-based amorphous alloy (Fe-based metal glass alloy) powder and a binder. In the present embodiment, the Fe-based amorphous alloy can be produced, for example, in a powder form by an atomizing method or in a strip shape (ribbon form) by a liquid quenching method.

  The Fe-based amorphous alloy powder has a substantially spherical shape or an ellipsoidal shape. A large number of the Fe-based amorphous alloy powders are present in the core, and the Fe-based amorphous alloy powders are insulated by a binder (binder resin).

Examples of the binder include epoxy resin, silicone resin, silicone rubber, phenol resin, urea resin, melamine resin, PVA (polyvinyl alcohol), acrylic resin and other liquid or powder resins, or water glass (Na2O-SiO2). ), Oxide glass powder (Na ₂ O—B ₂ O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ , PbO—BaO—SiO ₂ , Na ₂ O—B ₂ O ₃ —ZnO, CaO—BaO) the _{-SiO 2, Al 2 O 3 -B} 2 O 3 -SiO 2, B 2 O 3 -SiO 2), glassy material produced by a sol-gel method _{(SiO 2, Al 2 O 3} , ZrO 2, TiO 2 , etc. And the like).

  Further, zinc stearate, aluminum stearate or the like may be added as a lubricant. The mixing ratio of the binder is 5% by mass or less, and the addition amount of the lubricant is about 0.1% by mass to 1% by mass.

  In the present embodiment, each of the first core 11 and the second core 13 can be compression-molded alone. Therefore, unlike the structure shown in FIG. 7 in which the coil is compressed and sealed in the core, the molding pressure and annealing process are not limited by the coil wire coating material, and the optimum temperature for the core material is formed by high pressure. Annealing can be performed, and the original performance of the Fe-based amorphous alloy can be brought out appropriately.

  As shown in FIG. 1, the first core 11 is formed with a bottomed storage portion 11 a for storing the coil 12. Here, the planar shape of the storage portion 11a is slightly larger than the coil 12, and the height h1 of the side wall 11b of the storage portion 11a is slightly larger than the height h2 of the coil 12. Further, as shown in FIGS. 4 and 5, a cutout portion 11 c for accommodating the terminal portion 12 b of the coil 12 is formed on the back surface of the first core 11.

  The second core 13 is a lid formed with a predetermined thickness. For example, the upper surface 13a and the lower surface 13b are formed as flat surfaces.

  The coil 12 is formed by spirally winding a conductive wire with an insulating coating. The coil 12 includes a winding portion 12a and terminal portions 12b and 12b drawn from the winding portion 12a. The number of turns of the coil 12 is appropriately set according to the required inductance L. The coil 12 is an edgewise coil, and the cross-sectional area of the conductor in each turn can be increased as compared with the round wire coil, and a desired high inductance L can be obtained with a small number of turns. If a higher inductance L is required, a large number of winding turns are required in a narrow space. In that case, even if a round wire coil having a small cross-sectional area and capable of effectively utilizing the space is used. good.

  FIG. 2 shows a state where the coil 12 shown in FIG. 1 is installed in the storage portion 11 a of the first core 11. FIG. 4 is a longitudinal cross-sectional view of the inductor in the middle of production, cut in the height direction along the line AA in FIG. 2 and viewed from the direction of the arrow, and particularly shows a state in which the filler 16 is filled.

  The filler 16 shown in FIG. 4 includes a resin 17 and a magnetic powder 18. 4 and 5, the magnetic powder 18 in the filler 16 is schematically shown by black dots.

  In the first embodiment, the resin 17 having a Young's modulus of 0.1 GPa or more and 3.2 GPa or less is used. The filling amount of the magnetic powder 18 contained in the filler 16 was set to 30% by volume or more and 60% by volume or less.

  As shown in FIG. 4, the filler 16 flows into the gap a between the coil 12 and the side wall 11 b that constitutes the storage portion 11 a of the first core 11. Further, as shown in FIG. 4, the storage portion 11 a is filled with the filler 16, the upper surface and the lower surface of the coil 12 are covered with the filler 16, and the filler 16 is also applied to the upper surface 11 d of the first core 11. By covering the periphery of the coil 12 with the filler 16 in this way, it is possible to prevent the inductor from ringing and vibrating.

For the resin 17, an epoxy resin or a silicone resin having a Young's modulus of 0.1 GPa or more and 3.2 GPa or less can be preferably applied. Also in the magnetic powder 18, it is also possible to use a crystalline ferrite, the magnetic powder 18 is, for example, a composition formula _{Fe 100-abcxyzt Ni a Sn b} Cr c P x C y B z represented by _{Si t, 0at% ≦ a ≦} 10at%, 0at% ≦ b ≦ 3at%, 0at% ≦ c ≦ 6at%, 6.8at% ≦ x ≦ 10.8at%, 2.0at% ≦ y ≦ 9 It is preferable that the Fe-based amorphous alloy powder satisfy the following conditions: 0.8 at%, 0 at% ≦ z ≦ 8.0 at%, and 0 at% ≦ t ≦ 5.0 at%.

  The Fe-based amorphous alloy powder shown above is a metallic glass obtained by adding Fe as a main component and Ni, Sn, Cr, P, C, B, and Si within the above composition ratio. The Fe-based amorphous alloy powder is amorphous and has a glass transition point (Tg) and has excellent soft magnetic properties.

  The magnetic powder 18 contained in the filler 16 is preferably the same type as the Fe-based amorphous alloy constituting the core member 14. Here, the same type is the same powder (made in the same manufacturing process, or the composition is almost the same even in another process), or different powders (compositions are different). The basic characteristics required for the core of the inductor such as the magnetic flux density Bs and the magnetic permeability are substantially equal. However, the magnetic powder 18 contained in the filler 16 may be a material having a small magnetostriction such as an Fe—Ni alloy or an Fe—Al—Si alloy. In this case, a change in magnetic properties accompanying changes in the environment such as temperature and humidity can be kept low, which can be preferable depending on the intended use.

  As shown in FIG. 4, after filling the first core 11 with the filler 16, the second core 13 is superimposed on the first core 11 via the filler 16 as shown in FIGS. 3 and 5. 5 is a longitudinal sectional view taken along the line BB shown in FIG. 4 and viewed from the direction of the arrow, and shows a state after the terminal portion 12b shown in FIG. 3 is bent. Yes.

  As shown in FIG. 5, the filler 16 includes the coil 12 in the substantially enclosed space 15 between the bottomed storage portion 11a and the second core 13 located on the open end 11a1 side of the storage portion 11a. The gap a is filled. As shown in FIG. 5, there is a slight gap between the upper surface 11d of the first core 11 and the second core 13 because the filler 16 and the resin 17 are interposed, and the terminal portion 12b. There are some gaps in the lead-out portion from the first core 11. Therefore, the “substantially enclosed space” is not a space completely enclosed between the storage portion 11a and the second core 13, but as described above, there is a slight gap (from the upper surface 11d of the first core 11). Means that it may have a second core 13).

  In the present embodiment, the second core 13 is superposed on the first core 11 via the filler 16, and then heat treatment is performed to thermally cure the resin 17 constituting the filler 16. Thereby, the 1st core 11 and the 2nd core 13 can be joined. The temperature of the heat treatment referred to here is a temperature lower than the annealing temperature for stress relaxation when the core member 14 is formed, and is a temperature that does not adversely affect the coil wire covering material. In addition, since the temperature of the heat treatment applied to the coil wire covering material can be made lower than before, the material used as the coil wire covering material can be replaced with an inexpensive material having low heat resistance, thereby reducing the production cost. It becomes possible.

  Further, the terminal portion 12b shown in FIG. 3 is bent downward, and the terminal portion 12b is accommodated in a notch portion 11c formed on the back surface of the first core 11 as shown in FIG.

  As described above, in the first embodiment, the filling amount of the magnetic powder 18 contained in the filler 16 is set to 30% by volume or more and 60% by volume or less in the filler 16, and further 0.1 GPa or more and 3% or less. Resin 17 having a Young's modulus of 2 GPa or less was used. Accordingly, the filler 16 can be appropriately poured into the narrow space between the first core 11 and the coil 12 while keeping the fluidity of the filler 16 moderately, and the gap between the core member 14 and the coil 12 can be magnetized. A considerable amount of powder 18 can be interposed. As shown in FIG. 5, the filler 16 includes the coil 12 in the substantially enclosed space 15 between the bottomed storage portion 11a and the second core 13 located on the open end 11a1 side of the storage portion 11a. The gap a is filled. Since the enclosed space 15 is filled with the filler 16, the filler 16 can be held in the space 15 even when the Young's modulus is considerably low, and the resin has a Young's modulus with a lower limit of 0.1 GPa. 17 can be applied.

  Further, if the filling amount of the magnetic powder 18 is increased, the fluidity of the filler 16 is lowered and the gap a cannot be appropriately filled. Therefore, the upper limit is set to 60% by volume.

  In the present embodiment, even when an Fe-based amorphous alloy powder having a large magnetostriction is used for the core member and an Fe-based amorphous alloy powder is also used for the filler 16, the internal stress of the filler 16 itself is reduced. The stress acting on the core member 14 can be reduced.

  As described above, in this embodiment, the inductance L can be improved. In particular, in this embodiment, the filling amount of the magnetic powder 18 contained in the filler 16 is set to 30 vol% or more and 60 vol% or less in the filler 16, and further, a Young of 0.1 GPa or more and 3.2 GPa or less. By using the resin 17 having a rate, as shown in the experimental results to be described later, it is possible to obtain a higher inductance L than a coil-encapsulated magnetic core formed by compression-molding a core in a state where the coil is encapsulated.

  The filling rate of the magnetic powder 18 contained in the filler 16 is preferably 40% to 60% by volume, more preferably 45% to 60% by volume, or 40% to 55% by volume, More preferably, it is 45 volume% or more and 55 volume% or less. Thereby, the inductance L can be improved more effectively.

  The Young's modulus of the resin 17 is preferably 0.9 GPa or more and 3.2 GPa or less. Furthermore, it is more preferable to set the Young's modulus of the resin 17 to 0.9 GPa or more and 1.5 GPa or less. Thereby, the inductance L can be improved more effectively.

  Moreover, in 2nd Embodiment, the filling amount of the magnetic powder 18 contained in the filler 16 is set to 40 volume% or more and 55 volume% or less in the filler 16, and also 3.2 GPa or more and 5.2 GPa or less Resin 17 having Young's modulus was used. When the Young's modulus of the resin 17 and the filling rate of the magnetic powder 18 are increased, the filler 16 cannot be appropriately poured into the gap a between the coil 12 and the inductance L is reduced. In an experiment to be described later, by adjusting to the above Young's modulus and filling amount, a higher inductance L can be obtained as compared with a coil-enclosed magnetic core formed by compression-molding a core in a state where a coil is encapsulated.

Hereinafter, an inductor having the structure of FIG. 5 (complete cross-sectional view) as an example was manufactured.
The same powder was used for the Fe-based amorphous alloy powder contained in the core member 14 and the filler 16 of the inductor. The Fe-based amorphous alloy powder used in the experiment was manufactured by the water atomization method, and the composition was Fe _71.4 Ni ₆ Cr ₂ P _10.8 C _7.8 B ₂ . A Fe-based amorphous alloy powder is mixed with acrylic resin; 3% by mass, lubricant (zinc stearate); 0.3% by mass, press pressure is 1471 MPa, annealing temperature is about 350 ° C., and holding time is 1 As time, the 1st core 11 provided with the accommodating part 11a and the 2nd core 13 of the cover body were formed. The horizontal dimension, the vertical dimension, and the height dimension of the resulting first core 11 were 10 mm, 10 mm, and 3.19 mm, respectively. Moreover, the horizontal dimension, the vertical dimension, and the height dimension of the 2nd core 13 were 10 mm, 10 mm, and 0.61 mm, respectively. As shown in FIG. 4, the storage portion 11 a constituting the first core 11 is formed so that the side wall 11 b is slightly higher than the coil 12 when the coil 12 is stored. The gap a between the coil 12 and the side wall 11b shown in FIG. 4 was about 0.03 to 0.07 mm.

  The resin constituting the filler 16 includes an epoxy resin having a Young's modulus E of 0.9 GPa (sample 1 in Table 1 below) and an epoxy resin having a Young's modulus E of 1 GPa (sample 2 in Table 1 below). An epoxy resin having a Young's modulus E of 1.4 GPa (sample 3 in Table 1 below), an epoxy resin having a Young's modulus E of 1.5 GPa (sample 4 in Table 1 below), and a Young's modulus E of 3.2 GPa Epoxy resin (sample 5 in Table 1 below), epoxy resin with Young's modulus E of 4.9 GPa (sample 6 in Table 1 below), epoxy resin with Young's modulus E of 5.15 GPa (Table 1 below) Then, sample 7) and an epoxy resin with Young's modulus E of 5.6 GPa (sample 8 in Table 1 below) were used. The Young's modulus of the resin can be adjusted as appropriate by using a silicone resin in addition to the above epoxy resin, adding various additives to the resin, or adding a fine filler as required.

  In the experiment, in the state shown in FIG. 5, sample 1 was subjected to pre-curing at 100 ° C. for 3 hours, sample 3 was precured at 70 ° C. for 1 hour and post-cured at 150 ° C. for 5 hours, and sample 6 was heat-treated at 120 ° C. for 20 minutes. The resin 17 of the filler 16 was thermally cured. The other samples were thermally cured at 50 ° C. to 150 ° C. for 20 minutes to 3 hours, and post-cured at 70 ° C. to 150 ° C. for 2 hours to 5 hours as needed.

As the reference value of the inductance L, the inductance L of the coil-encapsulated magnetic core shown in FIG. The same Fe _71.4 Ni ₆ Cr ₂ P _10.8 C _7.8 B ₂ composition as that described above was used as the Fe-based amorphous alloy powder used for the coil-filled magnetic core. A Fe-based amorphous alloy powder is mixed with acrylic resin; 2% by mass, lubricant (zinc stearate); 0.3% by mass, press pressure is 590 MPa, annealing temperature is about 350 ° C., and holding time is 1 As time, a coil encapsulated magnetic core was formed. The horizontal dimension, the vertical dimension, and the height dimension of the resultant coil-enclosed magnetic core were 10 mm, 10 mm, and 3.8 mm, respectively.

  The coil used in the experiment was an edgewise coil having the same number of turns and the same size in both the example of FIG. 5 and the comparative example of FIG.

  Inductance L was measured using HEWLETT PACKARD 4285A at a frequency of 100 kHz and a measurement signal current of 10 mA.

In the experiment using the inductor of the embodiment shown in FIG. 5, the above-described plurality of resins are used, and the filling rate r of the magnetic powder contained in the filler is 0% by volume, 20% by volume, 30% by volume, 40%. The inductance L was measured while changing the volume%, 45 volume%, 50 volume%, 55 volume%, and 60 volume%.
The measurement results are shown in Table 1 below and FIG.

  In FIG. 6, the horizontal axis represents the Young's modulus of the resin, and the vertical axis represents the inductance L. 6 is divided into FIG. 6 (a) and FIG. 6 (b). FIG. 6A and FIG. 6B are graphs showing the same experimental results, but the range of application of Young's modulus is different. Hereinafter, experimental results will be described with reference to FIG.

  As shown in FIG. 6A and Table 1, when the Young's modulus E of the resin is 1 GPa and 1.4 GPa, and the filling rate of the magnetic powder is 30% by volume or more, the inductance is larger than the reference value (Ref). L was found to be obtained. In the experiment, the maximum value of the filling rate of the magnetic powder was set to 60% by volume. However, when the filling rate was larger than this, the fluidity of the filler was lowered.

  When the Young's modulus E of the resin was 4.9 GPa and the filling rate of the magnetic powder was 60% by volume, the inductance L rapidly decreased. When the filling rate is 60% by volume and the Young's modulus E of the resin is 0.9 GPa to 3.2 GPa, an increasing tendency of the inductance L was observed by increasing the filling rate of the magnetic powder. In an experiment in which E was set to 4.9 GPa, such a tendency was not always observed. Further, when the Young's modulus E of the resin is increased to 4.9 GPa, the inductance L is higher than the reference value (Ref) when the filling rate of the magnetic powder is 0% by volume, 20% by volume, 30% by volume and 60% by volume. Below.

The Fe-based amorphous alloy powder contained in the core and filler has a large magnetostriction. Specifically, it has a magnetostriction λs of about 10 × 10 ^{−6 to} 27 × 10 ⁻⁶ . For this reason, when a resin having a high Young's modulus is used, the internal stress in the filler is increased, and the stress applied to the core member is increased. As shown in FIG. 5, since the filler 16 is filled in the substantially enclosed space 15, in order to obtain a high inductance L, the fluidity of the filler 16 is ensured and the internal stress is reduced. is important.

  Then, as shown in FIG. 6A, when the filling rate of the magnetic powder is 30% by volume or more and 60% by volume or less, the inductance L is set to the reference value (Ref) by setting the Young's modulus of the resin to 3.2 GPa or less. ).

  The lower limit of the Young's modulus of the resin was set to 0.1 GPa. Even if the lower limit of the Young's modulus is reduced to about 0.1 GPa, as shown in FIG. 5, the coil 12 can be held in the substantially enclosed space 15, and the terminal portion 12b shown in FIG. As shown in FIG. 5, it was possible to appropriately bend up to the notch portion 11c on the back surface. Therefore, the lower limit value of the Young's modulus of the resin was set to 0.1 GPa or more.

  As described above, in this example, the filling rate of the magnetic powder contained in the filler was set to 30% to 60% by volume, and the Young's modulus of the resin was set to 0.1 GPa to 3.2 GPa. As a result, it was found that an inductance L larger than the reference value (Ref) can be obtained.

  It has also been found that an inductance L larger than a reference value can be obtained more reliably by setting the filling rate of the magnetic powder to 40 volume% or more. Moreover, it is estimated that the inductance L larger than a reference value can be obtained more effectively by making the filling rate of magnetic powder 55 volume% or less, or 45 volume% or more.

  From the above, the filling rate of the magnetic powder is preferably 40% by volume or more and 60% by volume or less, more preferably 45% by volume or more and 60% by volume or less, or 40% by volume or more and 55% by volume or less, more preferably It was set to 45 volume% or more and 55 volume% or less.

  Moreover, it is preferable to set the Young's modulus of the resin to 0.9 GPa or more and 3.2 GPa or less. The Young's modulus of the resin is more preferably 0.9 GPa or more and 1.5 GPa or less. As a result, it has been found that an inductance L larger than the reference value (Ref) can be obtained more effectively.

  As shown in FIG. 6A, when the Young's modulus E of the resin is 0.9 GPa or more and 1.5 GPa or less, and the filling ratio of the magnetic powder is 40 vol% or more and 60 vol% or less, the inductance is about 0.47 μH or more. L was obtained, and it was found that a high inductance L of 0.1 μH or higher compared to the reference value (E = 0.366 μH) could be obtained.

Next, as shown in FIG. 6B, a Young's modulus range different from that in FIG.
In FIG.6 (b), the Young's modulus of resin was set to 3.2 GPa or more and 5.2 GPa or less. Furthermore, the filling rate of the magnetic powder was set to a range of 40 volume% to 55 volume%. As a result, it was found that a higher inductance L than the reference value (E = 0.366 μH) can be obtained.

DESCRIPTION OF SYMBOLS 10 Inductor 11 1st core 11a Storage part 12 Coil 12a Winding part 12b Terminal part 13 2nd core 14 Core member 16 Filler 17 Resin 18 Magnetic powder

Claims (9)

A coil, a core member having a bottomed storage part for the coil, a core member configured to cover the opening side of the storage part, and the storage part and the storage part being opened. A filler that fills a gap with the coil in a substantially enclosed space between the second core located on the end side,
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
The filler is composed of resin and magnetic powder,
The Young's modulus of the resin is 0.1 GPa or more and 3.2 GPa or less,
The inductor is characterized in that the magnetic powder is contained in the filler in a range of 30% by volume to 60% by volume.   The inductor according to claim 1, wherein the magnetic powder is contained in the filler in a range of 40% by volume to 60% by volume.   The inductor according to claim 1 or 2, wherein the Young's modulus of the resin is 0.9 GPa or more and 3.2 GPa or less.   The inductor according to claim 1 or 2, wherein a Young's modulus of the resin is 0.9 GPa or more and 1.5 GPa or less. A coil, a core member having a bottomed storage part for the coil, a core member configured to cover the opening side of the storage part, and the storage part and the storage part being opened. A filler that fills a gap with the coil in a substantially enclosed space between the second core located on the end side,
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
The filler is composed of resin and magnetic powder,
The Young's modulus of the resin is 3.2 GPa or more and 5.2 GPa or less,
The inductor is characterized in that the magnetic powder is contained in the filler in a range of 40% by volume to 55% by volume.   The inductor according to any one of claims 1 to 5, wherein the magnetic powder contained in the filler is an Fe-based amorphous alloy powder. The Fe-based amorphous alloy powder, the composition formula is represented by _{Fe 100-abcxyzt Ni a Sn b} Cr c P x C y B z Si t, 0at% ≦ a ≦ 10at%, 0at% ≦ b ≦ 3at% 0 at% ≦ c ≦ 6 at%, 6.8 at% ≦ x ≦ 10.8 at%, 2.0 at% ≦ y ≦ 9.8 at%, 0 at% ≦ z ≦ 8.0 at%, 0 at% ≦ t ≦ 5. The inductor according to any one of claims 1 to 6, which is an Fe-based soft magnetic alloy powder of 0 at%. A coil, a core member having a bottomed storage part for the coil, a core member configured to cover the opening side of the storage part, and the storage part and the storage part being opened. A filler that fills a gap with the coil in a substantially enclosed space between the second core located on the end side,
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
A magnetic powder is mixed with a resin having a Young's modulus of 0.1 GPa or more and 3.2 GPa or less in a range of 30% by volume or more and 60% by volume or less to produce the filler.
The coil is housed in the housing portion of the first core, the filler is filled on the opening side of the housing portion, and then the second core is covered on the opening side of the first core. And the second core are joined together. A coil, a core member having a bottomed storage part for the coil, a core member configured to cover the opening side of the storage part, and the storage part and the storage part being opened. A filler that fills a gap with the coil in a substantially enclosed space between the second core located on the end side,
The core member is formed by compression molding an Fe-based amorphous alloy powder and a binder,
A magnetic powder is mixed in a range of 40% by volume to 55% by volume with a resin having a Young's modulus of 3.2 GPa or more and 5.2 GPa or less to produce the filler.
The coil is housed in the housing portion of the first core, the filler is filled on the opening side of the housing portion, and then the second core is covered on the opening side of the first core. And the second core are joined together.

Images