JP5110628B2 - Wire ring parts - Google Patents

Description

  The present invention relates to a wire ring component such as a choke coil or a transformer for an electronic device suitable for use in a region of 1 MHz or less and a maximum applied magnetic field H = 3.98 kA / m or more.

  Application destinations of these wire ring components include, for example, wire ring components for increasing voltage control and decreasing voltage control used for solar power generation, wind power generation, and the like. The implementation of concrete measures to combat global warming has become an urgent task, and competition for clean energy such as fuel cell vehicles has intensified. Furthermore, in the private sector such as home and business, the government and local governments have strengthened subsidies, and have begun to establish a decentralized power generation system that does not emit greenhouse gases such as solar power generation, small wind power generation, and fuel cell power generation. Yes.

  As element technologies common to these fuel cell vehicles and distributed power supply facilities, a DC voltage step-up / down circuit (DD converter) and a DC-AC converter circuit (inverter) are inserted in the power supply system. It is necessary not to consume power unnecessarily in this circuit.

  In the case of power conversion from direct current to alternating current by an inverter circuit, a filter inductor for preventing outflow of harmonic current to the output system, and a voltage raising / lowering circuit by a DD converter instantaneously convert electric energy. Inductors that can be stored as magnetic energy are required, and all of them require large-capacity inductors that are smaller and lighter, save energy, save resources, and reduce noise.

  The conventional magnetic core has adjusted the direct current superposition characteristics by a macro gap. For this reason, leakage magnetic flux was generated and audible noise was easily generated. Moreover, the magnetic core of the closed magnetic path has been manufactured by press molding or injection molding in order to increase the initial permeability. However, when these molding methods are employed, investment in large-scale and expensive equipment and molds is required for industrialization. In addition, as a method of manufacturing the magnetic core, there is a method of casting at a low pressure or a reduced pressure. However, since it is necessary to ensure fluidity, there is a problem that the filling rate of the magnetic powder cannot be increased so much.

  As a performance problem, when the drive frequency or standby mode frequency of a coil component is several kHz to several tens of kHz in the audible range, mutual attraction force is generated between the coil wires and between the coil and the magnetic core. Caused vibration occurs. For this reason, there is a problem of generating audible noise and beat.

  Further, Patent Document 1 discloses an invention relating to a small magnetic element for large current and a method for manufacturing the same. Here, LSIs such as a CPU of a high permeability electronic device are highly integrated and supplied thereto. Since a current of several A to several tens of A may be supplied to the power supply circuit, the coil was developed to provide a magnetic element suitable for a large current application of these various electronic devices. It is said to be a magnetic element that is embedded in a composite magnetic member containing powder and a thermosetting resin, and combined with a magnetic member made of a sintered compact of ferrite or powdered magnetic material of metal magnetic powder so that the magnetic path is in series. ing.

JP 2001-185421 A

  As is clear from the description in Patent Document 1, the frequency range targeted by the coil component described in Patent Document 1 is a so-called “high frequency”, which is a frequency region far exceeding the audible frequency. In fact, Patent Document 1 has a description of “several hundred kHz to MHz”, and the term “high frequency” is frequently used as a keyword.

  Even if the air gap part vibrates at a very high frequency of several hundred kHz to MHz, it will only generate sound that cannot be heard by the human ear, and it is possible that it will result in audible noise and beating as described above. Absent.

  Therefore, it is appropriate to consider a solution for audible noise and beat caused by driving in the audible frequency band, apart from the technique described in Patent Document 1. In addition, the coil component that is the target in Patent Document 1 is a coil component for a low-power system, as is clear from the size illustrated. Therefore, as a matter of course, a withstand voltage performance of several hundred volts or more or an unnecessary pulse current performance of several hundred amperes or more (resistance to unwanted current noise such as surge current) cannot be expected.

  Thus, it is appropriate to consider that it is inappropriate to use the coil component described in Patent Document 1 for high power / low frequency applications.

  In view of the above, the present invention provides a wire ring component that has high withstand voltage performance and high anti-unnecessary pulse current performance and can suppress audible noise and beat even when driven at a frequency that is in the audible frequency range. One purpose is to provide

  Further, as a need that cannot be dealt with by the prior art, there is a winding integrated magnetic core without a macro gap. Even if the same soft magnetic material is used, the loss can be reduced by reducing the size of the winding as a single unit. At this time, the applied magnetic field H = N · I / le due to the magnetomotive force of the winding can be determined by the number of turns N, the maximum current I, and the effective magnetic path length le. Among these, the wire ring component can be reduced in size by reducing the effective magnetic path length le.

  However, since the applied magnetic field H becomes larger, it is necessary to obtain a higher relative magnetic permeability in the maximum applied magnetic field. In other words, even with the same material, up to which magnetic field is used, the effective cross-sectional area of the magnetic circuit differs depending on the external dimensions of the product. For this reason, the applied magnetic field and relative permeability required of the material change.

  As electronic devices are becoming smaller and smaller, high-efficiency magnetic materials are required, and as choke coils used at high frequencies, ferrite cores, silicon steel plates / amorphous ribbons, dust cores, etc. are used. .

  Selection of a suitable magnetic core can be classified according to the driving frequency of the electronic device and the maximum applied magnetic field of the inductor.

  When H is less than 3.98 kA / m, ferrite having a gap is mainly used.

  Up to H = 7.96 kA / m, silicon steel plates with gaps are mainly used.

  Up to H = 15.92 kA / m, a dust core or a silicon steel plate with a gap is used.

  Furthermore, at 15.92 kA / m or more (H = 31.84 kA / m level), it is difficult to select a suitable magnetic core.

  The magnetic permeability of each soft magnetic material is determined by the winding, the maximum current, and the magnetic path length, and particularly depends on the applied magnetic field.

Area A: H = less than 3.98 kA / m The saturation magnetic flux density of the ferrite core is small. Moreover, the following problems can be pointed out in the case of a ferrite magnetic core provided with a gap. First, magnetic flux leaks to the outside of the magnetic core, generating eddy currents on the copper wire surface.

  When the litz wire is not used, the eddy current loss in the winding portion is large and the temperature rise of the inductor cannot be used remarkably. Next, as a countermeasure against eddy current loss in the winding portion due to leakage magnetic flux, a so-called litz wire in which a large number of thin copper wires are bundled is used. However, the litz wire has a lower space factor than the single wire, the direct current resistance increases, and a magnetic core having a larger size than that of the single wire is required to obtain the same inductance value. In addition, the litz wire is more expensive than the single wire.

  Ferrite has an excellent feature that its iron loss is remarkably lower than that of a silicon steel plate, an amorphous foil strip or the like. However, when the gap is provided as described above, the advantage cannot be fully utilized due to the eddy current loss in the winding portion due to the leakage magnetic flux. Furthermore, since ferrite is made of a metal oxide, it has the disadvantages that the saturation magnetic flux density is essentially lower than that of a metal-based soft magnetic material, the magnetic flux is easily saturated, and the temperature dependence of loss is large. For this reason, the ferrite magnetic core has to prevent magnetic saturation by increasing the cross-sectional area of the magnetic core as compared with a magnetic core made of a metallic soft magnetic material, and it is difficult to reduce the size of the magnetic core.

Region B: H = Unless than 7.96 kA / m For example, a ribbon having a thickness of 100 μm such as silicon steel can exhibit particularly superior high relative permeability in this range. When comparing with the same composition, the reason why the relative permeability is higher than the powder core of the powder is that the demagnetizing factor is lowered by using a thin ribbon, and the spin magnetization rotation mode having a low coercive force is used. . However, due to the increase in eddy current loss due to the ribbon thickness, it can only be applied up to about 40 kHz. Although thinner ribbons are being developed, the manufacturing costs are very high. There is also a problem of processing accuracy of the macro gap portion.

Area C: Up to H = 1.92 kA / m For example, Sendust green compact is used. A dust core produced by molding soft magnetic metal powder has a larger saturation magnetic flux density than ferrite, which is advantageous for downsizing, but is superior to ferrite in terms of permeability and iron loss. However, it is difficult to reduce the size.

  For example, a ferrite core without a macro gap has an inductance L value that suddenly decreases with a DC superimposed current that becomes a magnetic field of about H = 1 kA / m, whereas a dust core without a macro gap has a DC superimposed current. It decreases gradually against. This is presumably because there is a distribution in the micro-dispersion gap present in the dust core. In order to ensure the permeability up to higher magnetic fields, it seems necessary to adapt the micro gap. When the microgap is increased, the magnetic permeability of the magnetic core tends to decrease.

  The core loss of a dust core usually consists of hysteresis loss and eddy current loss, but the eddy current loss increases in proportion to the square of the frequency and the square of the size through which the eddy current flows. The generation of eddy current is suppressed by covering the electrically insulating resin or the like. On the other hand, it is necessary to apply a molding pressure of 500 MPa or more in order to increase the molding density of the dust core, so that the hysteresis loss increases as the magnetic material increases in distortion and the relative permeability deteriorates, thereby increasing the hysteresis loss. It was something to end up with. In order to avoid this, a post-molding heat treatment is performed as necessary to release the strain. However, when high-temperature heat treatment is required, an insulating binder for insulating the magnetic powder and maintaining the binding between the powders is necessary.

Area D: H = 31.84 kA / m level (15.92 kA / m or more)
Even in a dust core, in order to make the distribution of the magnetic flux density in a plurality of macro gaps and magnetic cores more uniform, it is an area that needs to be partially magnetized in the direction of difficult magnetization. It caused a significant increase in winding eddy current loss. In this region, it is difficult to select a suitable magnetic core.

  As described above, an object of the present invention is to provide a wire ring component such as a choke coil or a transformer having a good superposition characteristic at a large current, which is used in an electronic device up to a frequency of about 1 MHz. In particular, an object of the present invention is to provide a composite magnetic material that can secure a relative magnetic permeability in a region where the maximum applied magnetic field H is equal to or higher than 3.98 kA / m as a magnetic core material for a wire ring component and is suitable for downsizing.

  The present inventors may use a magnetic mixture having a microgap made of an admixture of magnetic powder and resin, not a macrogap, as a ring component with good high current direct current superposition characteristics. I found out. Furthermore, the present invention has led to an invention in which a magnetic core and a wire ring part using the magnetic core are constructed at a lower cost by using an adhesive made of a magnetic mixture containing a micro magnetic gap. It has also been found that higher characteristics can be achieved by combining conventional toroidal magnetic cores. However, the ratio between the inner diameter a and the outer diameter b of the conventional toroid is approximately in the range of b / a = 1.4 to 2.1, but the present invention is not limited to this inner / outer diameter ratio. . In particular, since it is considered effective to increase the filling ratio of the soft magnetic material in the magnetic mixture and to make the micro gap uniform, the present invention also examines the composition of the mixture for that purpose. It was obtained as a result.

That is, the present invention relates to a magnetic adhesive having an initial permeability μ of 10 or more and a plurality of magnetic core parts made of a molded product in the shape of a polygonal column, column, polygonal cylinder, or cylinder. in a Senwa part comprising the binding to magnet core and coil component, the magnetic adhesive, in admixture with soft magnetic powder and an organic binder, the effective demagnetizing field of the soft magnetic powder factor N is Ri der 0.4, the soft magnetic powder, and a first magnetic powder, and more consists of a second magnetic powder small, the average particle diameter φ1 of the first magnetic powder The average particle diameter φ2 of the second magnetic powder or nonmagnetic powder is φ2 = <φ1 / 15, and the volume fraction of the second magnetic powder or nonmagnetic powder is the first It is 40 vol% or less of the total of the magnetic powder and the second magnetic powder or the non-magnetic powder. A Senwa component which comprises a water silica.

  Further, the present invention is a wire ring part characterized in that a winding inclusion insulator obtained by surrounding with an insulating resin so as to exclude the end of the winding is used as the winding part.

  Moreover, this invention is a wire ring component characterized by including except the coil | winding edge part of the said coil | winding component in the said magnetic core.

  In addition, the present invention provides the wire ring component, wherein half or less of the second magnetic powder or non-magnetic powder is a powder having a particle diameter of φ1 / 50 or less.

Further, the present invention provides the wire ring component, wherein the anhydrous silica has an average primary particle diameter of 5 to 50 nm and is contained in the magnetic adhesive in an amount of 1 vol% or less (excluding 0 vol%). .

  The present invention also provides a wire ring component in which a specific permeability magnetic core member having an initial permeability μ of 1 to 2 is embedded in the magnetic core.

  The present invention further provides a wire ring component further comprising a holding case, wherein at least a part of the magnetic adhesive is solidified or hardened in the case.

  In the present invention, a magnetic core component of a molded body having a large relative permeability is used as the magnetic core, and a magnetic mixture comprising a magnetic powder or the like and an organic binder such as a resin is formed in the gap between the magnetic core components of the molded body. A closed magnetic circuit core having a high initial permeability can be obtained by binding with a magnetic adhesive and filling a magnetic mixture. Conventionally, closed cores with high initial permeability have been manufactured by press molding or injection molding, but investment in large-scale and expensive equipment and molds is required, especially for large currents, An expensive investment was required for the manufacturing equipment for the wheel ring parts. However, in the present invention, since a magnetic core part of a molded body is used as the magnetic core, it is only necessary to mold a magnetic core part in which the magnetic core is divided. Therefore, even a complicatedly shaped magnetic core can be manufactured relatively easily. This eliminates the need for large molding equipment and reduces capital investment. In addition, by using a magnetic core component of a molded body, it is possible to manufacture a magnetic core having a high initial permeability at a lower cost than manufacturing a magnetic core using only a magnetic admixture.

  In addition, since the space factor in the magnetic core of the magnetic material and the inorganic filler can be increased in the present invention, the heat dissipating property and crack resistance of the wire ring component are improved, and the device is miniaturized as the wire ring component. Is possible.

  In the wire ring component, it is not necessary to use a macro gap to improve the DC superposition characteristics, and furthermore, the gap can be bound with a magnetic adhesive so that the movement of the winding can be fixed. The amplitude of the vibration that causes audible noise / beat is reduced even when driven by.

In the present invention, if the magnetic core of the conventional closed magnetic circuit as a wire ring component, a magnetic field that would be magnetically saturated,
H1 = 15.92 kA / m
H2 = 31.84 kA / m
H3 = 79.6 kA / m
In this case, a higher relative permeability can be obtained, and further, by using a molded body, the relative permeability (initial permeability) at H0 = 5 A / m or less (equivalent to initial permeability) can be significantly increased. did it.

  A wire ring component according to an embodiment of the present invention is an assembly of a magnetic core component and a winding component of a molded body having a high initial permeability, and a gap between these magnetic core components is made of a soft magnetic material powder or the like and a resin or the like. A magnetic admixture made of an organic binder is bound with a magnetic adhesive and filled with the magnetic admixture. In the wire ring component of the present invention, a magnetic core component and a winding component of a molded body having a high initial permeability are arranged in a case or a mold for mold release, and a magnetic mixture composed of soft magnetic powder and resin is poured. And can be produced by solidifying or curing the blend. Further, the magnetic core part and the winding part of the molded body having a high initial permeability can be assembled and manufactured while the gap is bound with the magnetic adhesive.

  As a magnetic core component of a molded body having an initial permeability μ of 10 or more, a soft magnetic green compact is suitable. The shape of the magnetic core part of the molded body is selected in consideration of easiness of manufacturing the molded body in a shape obtained by dividing the magnetic core such as a toroidal shape or a columnar shape.

  The magnetic powder constituting the soft magnetic compact that is a molded body is preferably a soft magnetic metal powder, more specifically, an Fe-based soft magnetic metal powder. More specifically, the soft magnetic metal powder is a powder selected from the group consisting of Fe-Si powder, Fe-Si-Al powder, Fe-Ni powder, and Fe amorphous powder. Here, the average Si content in the Fe—Si based powder is preferably 11.0% by weight or less. The average Si content in the Fe—Si—Al-based powder is preferably 11.0% by weight or less, and the average Al content is preferably 7.0% by weight or less. Further, the average Ni content in the Fe—Ni-based powder is preferably 30.0 wt% or more and 85.0 wt% or less.

  These soft magnetic metal powders are molded by press molding, injection molding, etc., and subjected to sintering and annealing heat treatment as necessary to obtain a desired soft magnetic green compact having an initial permeability μ of 10 or more. Can do.

  Moreover, as a magnetic core part of a molded body having a high initial permeability, a sintered body of soft magnetic ferrite may be used. If soft magnetic ferrite is used, a material having a high initial permeability can be obtained. Moreover, as a magnetic core component of a molded article having a high initial permeability, a laminated body such as an amorphous foil strip or a silicon steel plate may be used. Further, a magnetic core component of soft magnetic metal powder, a magnetic core component of soft magnetic ferrite, and a magnetic core component of a laminate may be used in combination.

  FIG. 7 is an explanatory view of the soft magnetic green compact. FIG. 7A is a perspective view of the soft magnetic green compact, and FIG. 7B is an enlarged view of a part of the soft magnetic green compact. As shown in FIG. 7, a normal toroidal green compact is molded by receiving a pressing pressure in a direction as indicated by a large arrow 12 from the top and bottom of the drawing. Further, a normal toroidal magnetic core is used by penetrating a wire ring in a hollow portion of the magnetic core, and a magnetic path is a direction (small arrow 13 direction) perpendicular to the pressing direction (large arrow 12 direction).

  Further, as shown in FIG. 7B, the soft magnetic metal powder is deformed by pressing, and the demagnetizing factor increases in the direction parallel to the pressing direction. Therefore, if the magnetic core parts are combined so that the direction of the magnetic path is parallel to the pressing direction, a higher relative magnetic permeability μ is exhibited in a higher magnetic field than in the case of using a normal toroidal magnetic core. Can be.

  As for the winding component, either a coated conductor whose surface is insulated may be used, or a winding inclusion insulator which is surrounded by an insulator except for its end may be used. However, in the case of a wire-in-wrap type wire ring component, the use of a wire-inside insulation has a high withstand voltage performance and a high unwanted pulse current performance, and is driven at a frequency that is in the audible frequency range. Is more desirable because it can suppress audible noise and beat. In the case of an integrated wire ring component that encloses a winding component in a magnetic core, a breakdown voltage failure due to a pinhole is likely to occur. In conventional inner iron type wire ring parts, measures are taken by bobbin, varnish impregnation and powder coating, but it is desirable to carry out by a method which is less likely to contain bubbles. Since the powder coating method is performed at normal pressure, there is a surface in which voids are generated between the coil wires and pinholes are easily generated. For this reason, for impregnation and adhesion between coils and between coil bases, it is desirable to produce a winding inclusion insulator using an impregnation / adhesive in which an inorganic filler is uniformly dispersed in a thermosetting epoxy resin. .

  What is necessary is just to select a resin with a small linear expansion coefficient suitably about resin as an organic binder, and can use an epoxy resin. Since it is an admixture, the epoxy resin as a resin is required to be liquid and have low viscosity. Therefore, compatibility with additives, curing agents and catalysts, and storage stability are also considered in the selection of specific epoxy resins. It is an important property to be. In consideration of such circumstances, epoxy resins such as bisphenol A type, bisphenol F type, and polyfunctional type can be used as the main agent, and aromatic polyamine type, carboxylic acid anhydride type, latent curing agent as the curing agent. A system type can be used. A typical example will be described below using a combination of a bisphenol A type epoxy resin and a solvent-free low-viscosity liquid aromatic amine curing agent.

  This resin may be another thermosetting resin such as a silicone resin, or may be cured without applying heat, such as a chemically reactive curable resin, an ultraviolet curable resin, or a photocurable resin. Resin may be used. Moreover, when it becomes press molding, the thermoplastic resin containing nylon, phenol, etc. which show the characteristic of a low viscosity at a certain pressure and temperature may be sufficient. Further, a base oil and a gelling agent having an appropriate melting point may be used. Of course, when a resin other than the thermosetting resin is used, a solidification or curing method may be employed depending on the resin.

  The magnetic powder constituting the magnetic adhesive of the magnetic admixture is preferably a soft magnetic powder, specifically, an Fe-based soft magnetic powder. More specifically, the Fe-based soft magnetic powder is preferably a powder selected from the group consisting of Fe-Si based powder, Fe-Si-Al based powder, Fe-Ni based powder, and Fe based amorphous powder. Here, as a particularly recommended composition range, the average Si content in the Fe—Si-based powder is preferably 11.0% by weight or less. The average Si content in the Fe—Si—Al-based powder is preferably 11.0% by weight or less, and the average Al content is preferably 7.0% by weight or less. Further, the average Ni content in the Fe—Ni-based powder is preferably 30.0 wt% or more and 85.0 wt% or less.

  In particular, it is desirable to use a substantially spherical powder as the magnetic powder used in the mixture. When a substantially spherical magnetic powder is used as the magnetic powder, the fluidity of the slurry-like admixture mixed with the resin increases, so that the filling rate of the magnetic powder in the admixture can be improved. Such a substantially spherical magnetic substance powder is obtained, for example, by a gas atomizing method. According to the gas atomization method, the particle size and shape of the magnetic powder have a certain degree of distribution, but as a guide, the average particle size D50 of the most standard magnetic powder (equivalent to 50% cumulative volume based on volume) (Indicating the diameter) is preferably 500 μm or less, and if it exceeds this, sufficient yield, characteristics and performance cannot be obtained. Further, a small particle size is desirable for filling the gaps in the molded body, and an average particle size D50 of about 100 μm is readily available, but a fine average particle size D50 of about 10 μm may be used.

  According to the gas atomization method, a non-spherical powder can be intentionally formed in addition to the substantially spherical powder as described above. Moreover, according to the water atomization method, an amorphous powder can also be obtained. In the present invention, non-spherical powder, amorphous powder, and other shapes of powder obtained by the above method can be used instead of the substantially spherical powder employed in the embodiment. The reason for employing a magnetic powder other than a substantially spherical shape is to use anisotropy due to its shape, for example. More specifically, for example, non-spherical, flat, or needle-shaped magnetic powder is mixed with a resin, and a predetermined magnetic field is applied before the resin is cured to perform anisotropic orientation of the powder group. The use method of hardening the resin after that can be considered.

  Conventionally, for example, in order to manufacture a wire-inner-type wire ring part having an outer volume of about 300 cc with Sendust green compact by press molding, a 1000-ton scale press facility is required. In the present invention, the magnetic core is divided into several tens of cc as the magnetic core component (the volume of the molded body is not limited to this value, and may be selected according to the manufacturing equipment as appropriate). In addition, since the casting method for gaps in the magnetic adhesive is selected, it is possible to share the magnetic core parts of the molded body among each product, reducing the cost of trial production and capital investment can do.

  As one means, we have selected a method of assembling a magnetic core part and a winding part of a molded body using a composite magnetic material having fluidity. This method has sufficient advantages even if it is inferior in terms of the filling rate of magnetic powder compared with press molding, and as shown below, this method has a sufficient filling rate of composite magnetic A body can be obtained and a wire ring part with sufficient characteristics can be provided.

In the present invention, studies were conducted with the goal of finding a composite magnetic material that increases the magnetic permeability of the following magnetic field regions H1, H2, and H3.
H0 = 5A / m (Set the minimum magnetic field of the LCR meter to measure the initial permeability)
H1 = 15.92 kA / m
H2 = 31.84 kA / m
H3 = 79.6 kA / m

  The component of the magnetic core can be appropriately changed in the applied magnetic field used above. For example, in order to slightly increase the initial permeability, a high initial permeability thin film layer may be formed on the surface of the magnetic powder. Here, as an example of the high initial permeability thin film, an Fe—Ni-based thin film can be given. In order to avoid an electrical short circuit due to the magnetic powder, the magnetic powder may be coated with one or more insulating layers before being mixed with the resin. Here, when a high initial permeability thin film is formed on the surface of the magnetic powder, an insulating layer may be coated on the formed high initial permeability thin film.

  Furthermore, it is preferable to add a non-magnetic powder to the mixture of the magnetic powder and the resin in order to ensure a high relative permeability in a higher magnetic field. Non-magnetic powders include, for example, inorganic powders made of silica powder, alumina powder, titanium oxide powder, quartz glass powder, zirconium powder, calcium carbonate powder, aluminum hydroxide powder, glass fiber, and granular resin. Can be mentioned. Further, a hollow glass sphere may be used as the nonmagnetic powder. Further, in order to extend the direct current superposition characteristics well into a higher magnetic field, a small amount of permanent magnet powder may be added to apply a magnetic bias to the magnetic core.

  Next, the admixture, particularly the magnetic powder will be described in detail. As the magnetic powder, 6.5% Si—Fe powder having an average particle diameter D50 = 160 μm was used, and silane coupling treatment was performed. The amount of silane coupling at this time was set to the minimum amount that can be slurried with a solidifying resin described later. This is because a silane coupling agent that does not contribute to bonding causes a decrease in adhesive strength, glass transition temperature, and the like.

  Next, using a thermosetting low-viscosity epoxy resin, mixing and defoaming were performed, and a slurry serving as a base of a composite magnetic body having a viscosity of 30 P (poise) at 80 ° C. was prepared. It was cast into a releasable silicone mold having a height of 11 mm and then cured at 115 ° C. for 4 hours. After measuring the density of the toroidal core of the cured product, 23 turns were wound with a φ1.5 mm wire, and the direct current superposition characteristics were confirmed. The viscometer (HADV-I +, manufactured by Brookfield) was a screw head type (PC-1TL, manufactured by VISCOMETER).

  Here, the composition of the magnetic powder was 6.5% Si—Fe powder having the highest magnetostriction and the highest saturation magnetic flux density, but the difference in particle shape was examined using powders having different production methods. When water atomized powder, gas atomized powder and pulverized powder are compared as production methods, the gas atomized powder has the highest filling rate. Regarding the filling rate that can be made into a slurry, the filling rate of the pulverized powder was only 58.6 vol%, and the filling rate of the gas atomized powder having the same average particle diameter was 63.6 vol%. Since the gas atomized powder is spherical, in the case of the casting type, it was possible to increase the filling rate by using the spherical powder.

  Further, in order to investigate the relationship between the filling rate and the powder particle size distribution for the magnetic powder, the powder with an average particle diameter D50 of 160 μm increased by gas atomization is classified by a sieve having 150 μm and 75 μm openings, Two types of powders having a particle size of 150 to 75 μm were prepared. The frequency distribution of the mother powder used for this is shown in FIG.

  In both powders with a particle size of 150 μm or more and powders with a particle size of 75 to 150 μm, the amount of resin added was increased and the filling rate was reduced to 60 vol%, but it became a high-viscosity paste and could be slurried. There wasn't. The reason for this is thought to be that narrowing the particle size distribution caused a decrease in the filling rate.

  As shown in FIG. 2, the mother powder has D25 (cumulative frequency 25% equivalent diameter from the small diameter side on the volume basis) = 110 μm peak distribution and D75 (equivalent diameter 75% from the small volume side on the volume basis) = It can be considered as the distribution sum with the distribution of the 230 μm peak.

  FIG. 3 shows the relationship between the particle size ratio, the mixing ratio, and the filling rate in a large and small two-component particle mixed packed bed as an example of a true sphere packed model. FIG. 3 is data presented by Michitaka Suzuki: Himeji Institute of Technology, Powder and Particle Engineering Laboratory. When the large particles and the small particles are mixed and filled, the small particles enter the gaps between the large particles, so the gaps are reduced and the particles are packed densely. As shown in FIG. 3, the larger the particle diameter ratio, the larger the filling rate. Moreover, there is a peak in which the filling rate increases on the side where the mixing ratio of the small particle size powder is smaller as the particle size ratio is larger. Therefore, in order to obtain a high filling rate, it is effective to add a small amount of fine powder having greatly different particle sizes. In other words, it is effective to widen the particle size distribution. In the case of the above classified powder, it is considered that the particle size distribution was narrowed, which led to a decrease in the filling rate.

  In this case, the filling rate that can actually be made into a slurry is 63.6 vol%, which is less than the filling rate of about 74% that is expected when it is composed of only ideal primary spheres. Thus, it is considered that the fact is that the sphericity variation of the atomized powder and the width of the particle size distribution actually exist. In addition, since the surface of the magnetic powder surface is not smooth, agglomeration and bridges are likely to occur between a certain particle and a plurality of particles. In order to reduce the probability of occurrence, a low viscosity (low friction) is required in the process of uniform dispersion and molding.

  The present invention relates to a magnetic core for inductors such as choke coils and transformers used in electronic equipment up to about 1 MHz. As an example, it is determined whether or not there is a problem of eddy current loss of the inductor at the drive frequency f = 10 kHz. Here, the driving frequency f = 10 kHz of the product, the relative permeability μ of the powder composition μ = 1000, and the specific resistance ρ = 80 μΩcm of the powder composition bulk are used as constants.

When the skin depth δmm = (2 / (2πfμσ)) ^0.5 is calculated, the skin depth is 0.14 mm, and the corresponding particle diameter is 0.28 mm. The average particle diameter D50 of the currently used dust material is 0.16 mm, and the particle diameter D90 (equivalent diameter of 90% from the small diameter side on the volume basis) is about 0.28 mm. I think that the. Further, the frequency characteristic of the initial permeability μ does not decrease at 10 kHz, and the influence of the skin effect is sufficiently small, but the particle size of 280 μm or more may be affected. Thus, it is desirable that the maximum particle size of the magnetic powder is appropriately selected according to the drive frequency.

  Highly filled and highly superimposed magnetic cores can be obtained by adding secondary and tertiary particles of small diameter spheres. Here, the secondary and tertiary particles of the small-diameter sphere can be classified into a case where magnetic powder is used and a case where nonmagnetic powder is used.

  First, when using a second magnetic powder having a smaller diameter, that is, as an example of high packing only with magnetic powder, adding magnetic powders having different particle sizes as secondary particles and tertiary particles at various blending ratios. Tried. The particle size of the additive powder is a spherical powder with secondary particles D50 = 9.8 μm and tertiary particles D50 = 1.0 μm. All the powders used are substantially spherical. The result is shown in FIG. FIG. 4 shows the filling rate when secondary particles (D50 = 9.8 μm) and tertiary particles (D50 = 1.0 μm) are added to primary particles (D50 = 160 μm) at various blending ratios. is there.

  The particle size was selected with the aim of achieving an effect that the filled powder dispersed in the epoxy resin was rearranged to facilitate high filling. From FIG. 4, the change of the filling rate with respect to the addition amount of the secondary particles shows a tendency to have one maximum value in a small proportion of fine particles as shown in FIG. However, the effect of adding the tertiary particles tends to have two peaks. In the mixing experiment of the powder having a sharp particle size in FIG. 3, it is shown that the effect of improving the filling rate is more remarkable when the particle size ratio is larger, that is, by adding finer particles. It seems that the degree of this effect is different in the powder having a broad particle size actually used. However, as shown in FIG. 4, it can be seen that an admixture with a high filling rate can be obtained by adjusting the particle size distribution.

  The inductance and its direct quantity superposition characteristics were evaluated at three representative locations in the region shown in FIG. Table 1 shows the blending ratio and results of the magnetic powder. In this specification, the blending ratio of powders and the like is expressed in vol%. As a reference for the vol%, the mixture obtained by mixing and curing the powder and the resin is set to 100 vol%, and the volume percentage of each powder and the like is calculated. As shown.

  As a result of the three types of blending, the relative magnetic permeability was measured as Sample No. 1, μ (H0) = 43.4, μ (H1) = 22.4, sample No. 2 gave a value of μ (H2) = 18.9. That is, the composite magnetic material that can be further miniaturized by the magnetic fields H0 = 5 A / m and H1 = 15.92 kA / m is the A region, and the composite magnetic material that can be further miniaturized by the magnetic field H2 = 31.84 kA / m is the B region. It is obtained with.

  Sample No. B in the B region As shown in FIG. 3, the reachable packing ratio with only the primary particles (D50 = 160 μm) is 63.6 vol%. Next, in order to perform gap filling, the filling rate can be made 74.6 vol% by adding 11 vol% of secondary particles (D50 = 10 μm). Furthermore, secondary particles (D50 = 10 μm) and 14 vol% of tertiary particles (D50 = 10 μm) are added together with 13 vol%, so that the filling rate can be 78.6 vol%.

  As described above, the magnetic field H0 = 5 A / m, H1 = 15.92 kA / m, H2 = by using the second magnetic powder having a smaller diameter (secondary and tertiary particles made of a magnetic powder having a small sphere). The relative magnetic permeability of the magnetic core at 31.84 kA / m can be increased.

  Next, as another example capable of obtaining a magnetic core having high filling and high superposition characteristics, when using a non-magnetic powder having a smaller diameter, that is, using a non-magnetic powder as secondary and tertiary particles of a small sphere Is described. First, the first magnetic powder and nonmagnetic powder were selected. The nonmagnetic powder used was an inorganic powder such as silica or alumina whose particle size can be changed over a wide range.

  First, as the first magnetic substance powder, the same 6.5% Si—Fe powder having an average particle diameter D50 of 160 μm as described above was used and subjected to silane coupling treatment.

  Next, as an inorganic powder silica, the sintering powder is an agglomerated particle when viewed with an electron microscope SEM, and has a specific surface area of 7 times or more compared to the spherical powder, and the resin component is easily absorbed. It is thought that the component will decrease. For this reason, although the powder for sintering is low-cost, it is difficult to obtain the effect of improving the filling rate of the present application.

  Furthermore, three kinds of other spherical powder, roundish powder and pulverized powder were compared. These powders were added in 3, 5, and 10 vol%, respectively, and the first magnetic powder amount was adjusted so that the total amount with the magnetic powder was 60 vol%. As a result, both the roundish powder and the pulverized powder could not be slurried. Therefore, it can be seen that it is desirable to use spherical powder in order to obtain the effect of improving the filling rate.

The results using spherical silica powder are shown below.
Table 2 shows the results obtained by selecting spherical silica having an average particle diameter D50 = 2.5 μm as secondary particles and spherical silica having an average particle diameter D50 = 2.5 μm as secondary particles, and adding these selected silicas in combination. Shown in

  It was confirmed that the relative magnetic permeability μ changes depending on the particle size and the added amount of the fine powder. Due to the blending of non-magnetic powder, the relative magnetic permeability is the sample No. 4 gave a value of μ (H3) = 7.6.

  That is, the relative magnetic permeability at the magnetic field H0 = 5 A / m, H1 = 15.92 kA / m, and H2 = 31.84 kA / m after addition is small compared to before the nonmagnetic powder addition (sample No. 3). Is shown. However, it can be seen that the magnetic field H3 = 79.6 kA / m exhibits a higher relative permeability.

  Furthermore, the sample No. As shown in FIG. 4, the secondary particles (D50 = 2.5 μm) are 5.5 vol% and the tertiary particles (D50 = 0.5 μm) are 5.5 vol% with respect to the primary particles (D50 = 160 μm). By adding them together, the filling rate can be 72.2 vol%.

  Sample No. B in the B region The result of examining the density distribution of the molded body of No. 3 will be described. In order to confirm the non-uniformity, the method and results of measuring the upper and lower density distribution of the cured product are shown. As a method, the slurry is cured in a syringe having a depth of about 45 mm and a diameter of 23 mm, and two portions of about 5 mm from the bottom and the surface of the cured product are cut into three cylinders. The weight of each cylinder, the average diameter, The average height was measured, and the average density of each cylinder was calculated from the weight and volume.

As a result, the density of the portion about 5 mm from the surface was low and the density of the portion about 5 mm from the bottom was high as described below.
a) A portion approximately 5 mm from the surface 5.17 g / cc (5% lower than the center ratio)
b) Center portion 5 to 37 mm portion 5.44 g / cc
c) About 5 mm from the bottom 5.71 g / cc (5% higher than the center)

  This phenomenon is caused by the particles being settled before the resin matrix of the admixture reaches heat curing, and the filling rate is locally improved, resulting in a heterogeneous structure of the magnetic core. This indicates that the direct current superimposition characteristic may be deteriorated. That is, from the results so far, it is considered essential to suppress precipitation of magnetic particles or non-magnetic particles in order to further improve the direct current superposition characteristics.

This will be discussed in more detail.
With respect to the target direct current superposition characteristics, it can be expected that the size of the micro gap formed between the individual particles varies depending on the location even if the filling rate of the magnetic powder is the same. FIG. 5 is a schematic view showing a dispersed state of the magnetic powder. A circle indicates a magnetic powder. In other words, if the magnetic powder (circles) as shown in FIG. 5 is uniformly dispersed, the average demagnetizing field should not be reduced, and a characteristic that is difficult to cause magnetic saturation should be obtained. is there. However, if the filling rate of magnetic powder (marked with ○) that indicates inappropriate is locally increased, the microgap between particles in such a place becomes smaller, resulting in a smaller demagnetizing field and a tendency to magnetic saturation. Become. Therefore, it is considered that eliminating such non-uniform distribution of the magnetic powder leads to higher characteristics. As one of the measures, it is considered effective to suppress the sedimentation of the magnetic powder that occurs during resin curing.

  As a measure for reducing the sedimentation rate of the particles, it is conceivable to increase the viscosity of the slurry. It is thought that it can be achieved simply by adding a thickener. However, since the casting method requires an operation of pouring the slurry into the mold, it is necessary that the viscosity is sufficiently lowered during the casting operation. Therefore, it is desirable to be able to utilize a property such as thixotropic in which the viscosity is reduced by applying shear or vibration. Therefore, a thixotropic agent is preferably used for uniform dispersion of the magnetic powder.

  Nano-sized fine particle anhydrous silica called nano silica is widely used in the adhesive industry as a highly active filler for increasing viscosity and imparting thixotropic properties. Silanol groups on the surface of nanosilica having a primary particle size of several nanometers are linked to the surface of the adjacent nanosilica by hydrogen bonding, form a three-dimensional network structure, and exhibit excellent viscosity. This hydrogen bond is a relatively weak bond, and by applying a slight shearing force (for example, vibration and stirring), the network structure is broken, broken up in units of chain-bonded particles, and loses viscosity. Due to this decrease in viscosity, good filling properties and rearrangement of fillers can be performed. On the other hand, in a stationary state, the mesh structure is regenerated, the viscosity is restored, and the sedimentation rate can be suppressed.

  These phenomena are called thixotropy phenomena and are important characteristics that improve the production and storage of magnetic slurries, as well as process capability and product properties.

  The thixotropic nature mainly depends on the resin used. For this reason, as a result of trying nano silica with different surface treatments, the most effective ones were those with a particle size of 4-7 nm and surface treatment with hydrophobic dimethyl silicone oil, which provided thixotropic properties. It was. The results using this nanosilica are shown in Table 3.

  As a result of the three levels of nanosilica addition, nanosilica 0.27 vol% and nanosilica 0.53 vol%, the relative magnetic permeability of nanosilica 0.27 vol% added was μ (H0) = 13.7, μ (H1) = The value of μ (H3) = 9.0 was obtained with 13.2, μ (H2) = 12.0, and nanosilica 0.58 vol% added.

  That is, when the magnetic fields H0 = 5 A / m, H1 = 15.92 kA / m, and H2 = 31.84 kA / m, the composite magnetic material that can be made smaller is 0.27 vol% nanosilica (sample No. 5 in the A region). In addition, in the magnetic field H3 = 79.6 kA / m, the composite magnetic material that can be further miniaturized is one with 0.58 vol% nano silica added (sample No. 6 in the A region). In particular, the value of μ (H3) = 9.0 is the maximum value obtained by experiments in the magnetic field H3 = 79.6 kA / m.

  Thus, regarding the direct current superposition characteristics in the high magnetic field H3, the effect by adding nano silica is great. However, with respect to the filling rate, the presence or absence of the addition of nano silica is not so large. As shown in Table 3, the filling rate is 71.1 vol% with addition of 0.27 vol% of nanosilica and 68.4 vol% with addition of 0.58 vol% of nanosilica with respect to 72.2 vol% without addition of nanosilica. .

  As described above, by using nonmagnetic powder (silica) as the secondary and tertiary particles of the small-diameter sphere, and further using nano silica, the relative magnetic permeability of the magnetic field H3 = 79.6 kA / m can be increased. That is, thixotropic properties are imparted by the addition of nanosilica, and the nonuniform distribution of the magnetic powder can be eliminated and the relative magnetic permeability can be improved by the sedimentation suppressing effect.

  When nanosilica is added, thixotropic properties are exhibited. Therefore, when casting is performed, it is preferable to perform casting while applying an appropriate stirring energy and vibrating. In principle, the hydrogen bond of nano silica is a relatively weak bond and loses its viscosity by applying a slight shearing force (for example, vibration, stirring).

  For this reason, the stirring conditions of the slurry were changed to 5 minutes, 15 minutes, and 20 minutes at a high speed stirring of 2000 rpm, which is considered to be the upper limit from the viewpoint of wear of the blades (diameter 50 mm) during mass production. As a result, it can be seen that Δμ / μ0, which is an index of the direct current superposition characteristic, takes a substantially constant value for 15 minutes or more, and this stirring condition may be adopted for 15 minutes or more.

  The casting was performed in a vacuum of 2700 Pa after deaeration of the stirred slurry at 50 Pa. Moreover, casting was performed while applying 50 Hz vibration with a vibrator (av-02: manufactured by Murata Seiko Co., Ltd.). Stop vibration and release to atmosphere after casting. Immediately after that, it was cured by heat treatment in a stationary state.

  FIG. 6 shows a similar system of flow / viscosity curves of an epoxy resin whose thixotropy is improved by adding nano silica. This is the result of measuring the ease of flowing at 50 ° C. isothermally during curing of the epoxy resin. A Brookfield rotational viscometer rotating at 2.5 rpm and a vibrator as a shearing force source are used. From this result, it can be seen that it is necessary to cast while applying a shear rate for uniform rearrangement of magnetic powder. In this study, it can be seen that by setting the vibration frequency of the vibrator to 50 Hz, the viscosity is substantially minimized and the rearrangement of the particles is facilitated. In addition, the shear rate is quickly reduced to zero after the slurry magnetic body is filled. By doing in this way, the viscosity of the slurry magnetic body shows a maximum value, and the sedimentation speed can be minimized.

FIG. 8 shows the initial magnetic permeability when the magnetic gap of the magnetic admixture is filled in the macro gap portion of the closed magnetic circuit core. The results shown in FIG. 8 are an effective magnetic path length le = 15.6 mm and an effective cross-sectional area S = 100 mm ^{2 made} of a compact sintered body of 6.5% Si—Fe (initial permeability μ = 100). Using a closed magnetic path core having a macro gap, the macro permeability length lg and the initial permeability of the magnetic adhesive are changed, and the initial permeability of the closed magnetic path core (number of windings N = 25 turns, H0 = 5A). / M).

  As can be seen from this figure, even with an air gap having a macro gap length of lg = 1 mm, the initial permeability is reduced by 50% compared to the case where there is no macro gap. However, it can be seen that the initial permeability can be improved to 95% by filling the macro gap with a magnetic adhesive having an initial permeability μ = 25.

  Therefore, in the wire ring component of the present invention, even if the magnetic core is configured by combining the magnetic core components, the gap is bound by the magnetic adhesive, so that high initial permeability can be maintained. I understand. Actually, 4 parts of magnetic core parts consisting of a 6.5% Si-Fe powder sintered body magnetic core (μ = 100) in which the toroidal core is divided into 4 parts are combined, and the total of the gaps at 4 places is 1 mm. When a toroidal core was produced by binding with a magnetic adhesive (μ = 25), a magnetic core with an initial permeability μ = 90 was obtained.

  In addition, since the magnetic core part of a molded product having a high initial permeability is used, in the examples, unlike the case of using only the magnetic admixture, even if the space factor of the soft magnetic powder in the magnetic admixture is somewhat low, It is possible to obtain a magnetic core with a high initial permeability. Accordingly, since the space factor of the soft magnetic powder has a margin, the soft magnetic powder is not limited to the spherical powder, and there is an advantage that a lower priced amorphous powder can be adopted.

  FIG. 1 and FIGS. 9 to 14 show the appearance of the product of the embodiment of the present invention using the above-described adhesive with a magnetic admixture. In each of these examples, a magnetic core part of a molded body having a high initial permeability is used, and a gap is bound with a magnetic adhesive made of a magnetic mixture to form a magnetic core. As a design point of the magnetic circuit, it is efficient if the cross-sectional area of each part of the entire magnetic path is substantially constant, but if designed to satisfy this, the center of the magnetic core may be hollow in some cases. is there. Since the wire ring component of the present invention is relatively easy to manufacture, there are not many restrictions on the shape. Therefore, it is designed so as not to generate a hollow, and a ferrite having higher permeability is sintered at a hollow portion. It is possible to improve the initial inductance by inserting a body or the like.

  In the following, a magnetic adhesive (initial magnetic permeability μ = 25) is used. Specifically, the magnetic powder is mixed with a thermosetting epoxy resin so that the filling rate of the magnetic powder becomes 70 vol%. The slurry is used. The binder resin was selected from a low-viscosity (80 ° C., 70 mPas or less) thermosetting epoxy. In addition, granular Sendust powder (particle diameter D50 = 30 μm) was selected as the magnetic powder.

  FIG. 1 is a partially transparent explanatory view showing the wire ring part of the first embodiment. The wire ring component of the first embodiment is an inner part of the winding component 3 as a magnetic core component of a molded article having a high initial permeability made of a sintered compact of 6.5% Si—Fe (μ = 100). One toroidal inner core part 8 and one toroidal outer core part 7 are arranged outside. The initial permeability μ of the wire ring component in this state was 41. In the product of the present invention in which the magnetic admixture 2 having an initial permeability μ of 25 was filled in the upper and lower spaces of the winding component 3, the initial permeability μ increased to 84.

  The relative permeability in a high magnetic field of the wire ring component of the first example was 25 in the relative permeability μdc in a 15.92 kA / m magnetic field.

  Furthermore, as a modification of the first embodiment, a toroidal inner core component 8 and an outer magnetic core component 7 may be further divided and the toroidal magnetic core components may be stacked and arranged. Since it is difficult to press-mold a too thick toroidal shaped product uniformly, it is easier to manufacture if it is divided into moderate thicknesses. Moreover, a magnetic core having a high initial permeability can be obtained by binding the laminated portion with a magnetic adhesive.

  FIG. 9 is a partially transparent explanatory view showing the wire ring part of the second embodiment. The wire ring component of the second embodiment is the inner side of the winding component 3 as a magnetic core component of a molded article having a high initial permeability made of a sintered compact of 6.5% Si-Fe (μ = 100). One toroidal inner core part 8, one toroidal outer core part 7 on the outside, one toroidal upper core part 5 on the upper side, and a lower toroidal magnet on the lower side. One core part 6 was arranged. The initial permeability μ of the wire ring component in this state was 81. The product of the present invention in which the gap between the magnetic core components is bonded to the average thickness of 0.2 mm using a magnetic adhesive made of the magnetic mixture 2 having an initial permeability μ of 25 is the initial permeability μ. Rose to 89.

  The relative permeability in a high magnetic field of the wire ring component of the second example was 70 in the relative permeability μdc in a 3.98 kA / m magnetic field.

  Further, as a modification of the second embodiment, the toroidal magnetic core is obtained by further dividing the toroidal inner core component 8, the outer magnetic core component 7, the upper magnetic core component 5 and the lower magnetic core component 6, respectively. You may use what laminated | stacked and arrange | positioned components. As in the case of the modification of the first embodiment, it is difficult to press-mold a too thick toroidal shaped product uniformly, so that it is easier to manufacture if it is divided into appropriate thicknesses. Similarly, a magnetic core having a high initial permeability can be obtained by binding the laminated portion with a magnetic adhesive.

  FIG. 10 is a partially transparent explanatory view showing the wire ring part of the third embodiment. The wire ring component of the third embodiment is an inner part of the winding component 3 as a magnetic core component of a molded article having a high initial permeability made of a sintered compact of 6.5% Si—Fe (μ = 100). One toroidal inner core part 8, one toroidal upper core part 5 on the upper side, and one toroidal lower core part 6 on the lower side are arranged. The initial permeability μ of the wire ring component in this state was 25. To this, a toroidal outer core part 7 made of a ferrite sintered body (μ = 1000) is arranged outside the winding part 3, and a magnetic adhesive made of the magnetic mixture 2 having an initial permeability μ of 25 is applied. The product of the present invention in which the gaps between the magnetic core components were bonded so that the average thickness was 0.2 mm increased in initial permeability μ to 125. Incidentally, in the case of the product of the present invention in which the magnetic admixture 2 is filled instead of using the toroidal outer core part 7 made of the ferrite sintered body of the third embodiment, the initial permeability μ is 75. It became.

   FIG. 11 shows an example in which the wire ring component of the present invention is mounted on a substrate. FIG. 12 shows an example in which the wire ring component of the present invention is mounted on a heat sink. Also in the case of the wire ring part of the present invention, it is preferable to design the cross-sectional area of each part of the entire magnetic path to be substantially constant, but it may be a toroidal shape in which the center of the magnetic core is hollow. As shown in FIG. 11 and FIG. 12, it can be mounted on a hollow portion of the wire ring component with a function of preventing the disconnection provided on the substrate 10 or the heat sink 11. In particular, since the wire ring component of the present invention is for a large current, heat dissipation is important, and attachment to a heat sink is often required. In addition, since the wire ring component of the present invention can increase the space factor of the magnetic material in the magnetic core, it has a high thermal conductivity and is advantageous in terms of heat dissipation.

  FIG. 13 is a partially transparent explanatory view showing the wire ring part of the fourth embodiment. In the wire ring component of the fourth embodiment, a magnetic material is also provided in the hollow portion of the wire ring component as shown in the first to third embodiments. In this case, the mounting examples as shown in FIGS. 11 and 12 cannot be adopted, but a wire ring component with higher initial permeability can be obtained.

  The wire ring component of the fourth embodiment is an inner part of the winding component 3 as a magnetic core component of a molded article having a high initial permeability made of a sintered compact of 6.5% Si—Fe (μ = 100). One toroidal inner core part 8, two toroidal outer core parts 7 on the outside, and a toroidal outer side made of a ferrite sintered body (μ = 1000) outside the winding part 3. A magnetic core part 7 and a columnar core part magnetic core part 9 made of a ferrite sintered body (μ = 1000) are arranged at the center. The outer magnetic core component 7 is formed by stacking a powder sintered body on top and bottom of a ferrite sintered body. The initial permeability μ of the wire ring component in this state was 125. The space above and below the winding component 3 is filled with a magnetic adhesive made of the magnetic mixture 2 having an initial permeability μ of 25, and the gap between the magnetic core components has an average thickness of 0.2 mm. The product of the present invention thus bonded had an initial permeability μ increased to 185.

  FIG. 14 is a partially transparent explanatory view showing the wire ring part of the fifth embodiment. The wire ring component of the fifth embodiment includes one toroidal outer magnetic core component 7 as a magnetic core component of a molded article having a high initial permeability made of a ferrite sintered body (μ = 1000) and a cylindrical shape thereof. The conductor 4 was penetrated in the center, and a magnetic adhesive made of the magnetic mixture 2 having an initial permeability μ of 25 was injected into the gap between the outer magnetic core component 7 and the conductor 4 and solidified. The wire ring component of the present invention had an initial permeability μ of 110. Further, a toroidal outer magnetic core part 7 as a magnetic core part of a molded body having a high initial permeability is replaced with a ferrite sintered body, and a 6.5% Si—Fe powder sintered body (μ = 100). Was used, the initial magnetic permeability μ of the wire ring component of the present invention was 32.

  In this example, the initial permeability μ = 1000 of the ferrite sintered body and the initial permeability μ = 100 of the powder sintered body are lower, but the initial permeability μ = of the magnetic core only of the magnetic admixture. It is important that the initial permeability is increased compared to 25. In the conventional wire ring component, the magnetic flux density is lower as it is farther from the conducting wire 4, but in the case of the wire ring of the fifth embodiment, the magnetic flux density can be made uniform and the initial permeability and the ratio in a high magnetic field can be achieved. It was possible to increase the permeability. Of course, the outer magnetic core component 7 may be an amorphous body other than a ferrite sintered body or a powder sintered body, or a laminated body such as a silicon steel plate.

  In addition, as a modification of the embodiment described above, the core part of the molded body having a high initial permeability can be replaced with a ferrite sintered body, a powder sintered body, an amorphous body, a silicon steel plate, or the like. Needless to say. Further, in the case of a laminated body, aside from the yield, depending on whether the lamination method is parallel to the direction of the magnetic field, perpendicular, or intermediate (30, 45, 60 degrees, etc.) The easy magnetization axis direction of the powder and the like can also be adjusted by adjusting the pressing direction and the orientation direction.

  Furthermore, when a specific permeability magnetic core member having an initial permeability μ = 1 to 2 is inserted into a part of the magnetic path, there is an advantage that the inductance of the wire ring component is less likely to be saturated even in a high magnetic field. The specific permeability magnetic core member incorporated in a part of the magnetic core may be selected so that the initial permeability μ is 1 or more and the shape is appropriately selected according to the magnetic field to be used. In this case, as the specific permeability magnetic core member, an inorganic filler-resin mixture, ceramics, or the like can be used. The resin used in the case of the resin mixture is preferably the same resin as the insulating resin used for the winding inclusion insulator, using a resin having good adhesion to the magnetic adhesive.

  In the present embodiment, since it is a combination of a magnetic core part of a molded body and a magnetic adhesive made of a magnetic admixture, the degree of freedom in manufacturing is high. Theoretically, a toroidal core shape with a uniform magnetic path cross-sectional area is ideal, but such a uniform magnetic path shape works advantageously in terms of reducing leakage magnetic flux and ensuring initial permeability. . In addition, it is possible to form a magnetic core of a composite magnetic material that does not lower the relative permeability in a high magnetic field. If this degree of freedom of shape is used, a wire ring part having a spherical product shape can also be manufactured.

  Furthermore, as described in the magnetic characteristics of the magnetic admixture alone in the example, there is an advantage that the inductance of the wire ring component is less likely to be saturated to a higher magnetic field by using the micro gap of the magnetic admixture. . Table 4 summarizes the composition of the powder and the effects of the present invention.

  The wire ring component of the present invention is manufactured by arranging a winding component and a magnetic core component in a mold, casting a mixture of a combination of releasable resins and curing it, producing a magnetic core, and removing the mold. Can be manufactured. Moreover, the wire ring component provided with the holding case can also be manufactured. By using part or all of the mold as a case, it is possible to manufacture without removing the mold. When the mold is not removed, it is not necessary to consider releasability, so that it is easy to manufacture a magnetic core having a complicated shape.

  Furthermore, a case that functions as a magnetic core may be used. For example, when a case functioning as a magnetic core is used as a common part with other parts, it is effective in a case where a winding part is once formed and then the winding part is placed in a case that is a common part. This case may be formed of other magnetic materials / alloys such as Fe-Ni alloys. When the case is made of a magnetic material, in order to ensure appropriate insulation performance, it is preferable to form an insulating film on the inner surface of the case and then cast the mixture to form a magnetic core. The case may be a ceramic case such as an alumina molded body, or may be made of an aluminum alloy.

A wire ring component including the case as described above and having a winding component and a magnetic core made of the mixture filling the space between the case can be provided. In addition, it is necessary to consider the clearance which absorbs the deformation | transformation amount estimated from the linear expansion coefficient from 21 * 10 < ^-6 > / degreeC-98 * 10 < ^-6 > / degreeC as a main point in the design of wire ring components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially transparent explanatory view, a front view, a plan view, and a perspective view showing a wire ring part of a first embodiment of the present invention. Frequency distribution of the volume-based particle size of the mother powder. The relationship between the particle size ratio, the mixing ratio, and the filling rate in the large and small two-component particle mixed packed bed. This figure is the data released by Michitaka Suzuki: Himeji Institute of Technology. Filling rate when secondary particles (D50 = 9.8 μm) and tertiary particles (D50 = 1.0 μm) are added to primary particles (D50 = 160 μm) in various mixing ratios. The schematic diagram which shows the dispersion state of a magnetic body powder. Similar to flow / viscosity curve of epoxy resin with improved thixotropy by adding nanosilica. Explanatory drawing of a soft magnetic compact. FIG. 7A is a perspective view of the soft magnetic green compact, and FIG. 7B is an enlarged explanatory view of a part of the soft magnetic green compact. Initial permeability when the magnetic gap of magnetic admixture is filled in the macro gap part of the closed magnetic path core. Explanatory drawing, a front view, a top view, and a perspective view of a partially transparent showing a wire ring part of the 2nd example of the present invention. Explanatory drawing, a front view, a top view, and a perspective view of a partial perspective showing a wire ring part of the 3rd example of the present invention. The example which mounted the wire ring components of this invention on the board | substrate. The example which mounted the wire ring components of this invention to the heat sink. Explanatory drawing, a front view, a top view, and a perspective view of a partially transparent view showing a wire ring part of a fourth embodiment of the present invention. Explanatory drawing, the front view, the top view, and perspective view of a partially transparent which show the wire ring components of 5th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wire ring component 2 Magnetic mixture 3 Winding component 4 Conductor 5 Upper magnetic core component 6 Lower magnetic core component 7 Outer magnetic core component 8 Inner magnetic core component 9 Core magnetic core component 10 Substrate 11 Heat sink 12 Large arrow 13 Small Arrow

Claims (7)

A magnetic material having an initial permeability μ of 10 or more and a plurality of magnetic core parts made of a molded product in the shape of a polygonal column, a cylinder, a polygonal cylinder, or a cylinder are bound by a magnetic adhesive having an initial permeability μ of 2 or more. A wire ring component comprising a core and a winding component, wherein the magnetic adhesive is a mixture of a soft magnetic powder and an organic binder, and the effective demagnetizing factor N of the soft magnetic powder is 0.4. Ri der below,
The soft magnetic powder comprises a first magnetic powder and a second magnetic powder having a smaller diameter,
The average particle diameter φ2 of the second magnetic powder or non-magnetic powder is φ2 = <φ1 / 15 with respect to the average particle diameter φ1 of the first magnetic powder, and the second magnetic powder or the non-magnetic powder The volume fraction of the magnetic powder is 40 vol% or less of the total of the first magnetic powder and the second magnetic powder or the non-magnetic powder;
Further , a wire ring component comprising nano-sized anhydrous silica .   The wire ring component according to claim 1, wherein a winding inclusion insulator obtained by surrounding with an insulating resin so as to exclude an end portion of the winding is used as the winding component.   The wire ring component according to claim 1, wherein a part other than a winding end of the winding component is included in the magnetic core. The wire ring component according to any one of claims 1 to 3, wherein half or less of the second magnetic powder or non-magnetic powder is a powder having a particle diameter of φ1 / 50 or less. The anhydrous silica has an average particle size of primary particles of 5 to 50 nm , and is contained in the magnetic adhesive in an amount of 1 vol% or less (excluding 0 vol% ) . The wire ring component described. The wire ring component according to any one of claims 1 to 5 , wherein a specific permeability magnetic core member having an initial permeability μ of 1 to 2 is embedded in the magnetic core. The wire ring component according to any one of claims 1 to 6 , further comprising a holding case, wherein at least a part of the magnetic adhesive is solidified or hardened in the case.

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