Filling device, filling method for composite magnetic material, and manufacturing method for metal composite core

Abstract

To provide a method for filling a composite magnetic material, a method for manufacturing a metal composite core and a filling device, which improve productivity of work of filling a composite magnetic material, and suppress variation in density of a metal composite core obtained by curing a resin.SOLUTION: A filling device 1 includes an extruder 2 for extruding a composite magnetic material, a cylindrical case 3 which is mounted on the extruder 2, with which the composite magnetic material extruded from the extruder 2 is filled, and a cover 4 for blocking the opening of the case 3. The extruder 2 has a cylindrical part 22 to which the composite magnetic material is injected, and a pressing part which is provided inside the cylindrical part 22, and extrudes the composite magnetic material toward the case 3. An outermost peripheral part of the pressing part is positioned in the vicinity of the inner peripheral surface of the cylindrical part 22, and the cover 4 has a hole which is a through hole penetrating in the cover 4. A resin constituting the composite magnetic material is contained in an amount of 3 wt.% or more and 5 wt.% or less with respect to the magnetic powder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filling device for filling a composite magnetic material that constitutes a metal composite core formed by curing a resin, a filling method for the composite magnetic material, and a manufacturing method for a metal composite core. [Background technology]

[0002] Coil components are used in a variety of applications, including office automation equipment, solar power generation systems, and automobiles. Examples of coil components include reactors, which are electromagnetic components that convert electrical energy into magnetic energy and store and release it.

[0003] A coil component mainly comprises a core, a coil, and a resin member. The coil is attached to the outer periphery of the core. The core serves as a magnetic path for the magnetic flux generated by the coil. A resin member is provided between the core and the coil to insulate them from each other.

[0004] The core is made of a magnetic material, such as a powder magnetic core. The powder magnetic core is made by compacting magnetic powder to produce a powder compact, which is then annealed. The powder compact is compacted at a pressure of 10 to 20 ton / cm. 2 This is a high pressure. Therefore, in the case of powder magnetic cores, the shapes are limited to those that can withstand this high pressure of pressure molding. Therefore, metal composite cores made of composite magnetic material, which is a mixture of magnetic powder and resin, are attracting attention. Metal composite cores are made by hardening the resin of the composite magnetic material. Metal composite cores do not require pressure molding, or even if it is required, they can withstand a pressure of 15.7 kg / cm. 2 Since the pressure is low, the freedom in core shape is increased. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-195737 Summary of the Invention [Problem to be solved by the invention]

[0006] If the resin content in the composite magnetic material is increased to, for example, 10 wt% relative to the magnetic powder, the characteristics of the coil component will deteriorate, so it is desirable to keep the resin content in the range of 3 wt% to 5 wt% relative to the magnetic powder.

[0007] However, if the resin content is between 3 wt% and 5 wt%, the viscosity of the composite magnetic material increases and its flowability deteriorates. As a result, the composite magnetic material cannot be filled into the case by machine and must be done by hand, resulting in poor productivity. Furthermore, because it is done by hand, the density of the metal composite core varies and is unstable.

[0008] The object of the present invention has been proposed to solve the above-mentioned problems, and is to provide a filling device, a filling method for composite magnetic material, and a manufacturing method for metal composite cores that can increase the productivity of the filling work of composite magnetic material and suppress density variations in metal composite cores. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the filling device of the present invention is a filling device that mixes resin and magnetic powder and fills a composite magnetic material that constitutes a metal composite core formed by hardening the resin, and is characterized in that it includes an extruder that extrudes the composite magnetic material, a cylindrical case that is attached to the extruder and filled with the composite magnetic material extruded from the extruder, and a cover that closes the opening of the case, the extruder has a cylindrical portion into which the composite magnetic material is injected, and a pressing portion that is provided inside the cylindrical portion and extrudes the composite magnetic material toward the case, the outermost portion of the pressing portion is located near the inner surface of the cylindrical portion, the cover has holes, and the resin that constitutes the composite magnetic material is contained in a range of 3 wt% to 5 wt% with respect to the magnetic powder.

[0010] Furthermore, the present invention provides a method for filling a composite magnetic material, which includes a composite magnetic material preparation step of mixing magnetic powder and resin to prepare a composite magnetic material, an injection step of injecting the composite magnetic material into a filling device, and a filling step of filling a cylindrical case with the composite magnetic material, wherein the filling device has a cylindrical portion into which the composite magnetic material is injected, and a pressing portion provided inside the cylindrical portion and extruding the composite magnetic material toward the case, and the case has an opening on the opposite side to where the composite magnetic material is filled, which is closed with a cover, and the cover has a hole, and in the composite magnetic material preparation step, the resin is added in a range of 3 wt % to 5 wt % relative to the magnetic powder to prepare a clay-like composite magnetic material, and in the filling step, the outermost peripheral portion of the pressing portion is located near the inner peripheral surface of the cylindrical portion, and the pressing portion extrudes the composite magnetic material that has flowed into the cylindrical portion toward the case.

[0011] Furthermore, a method for manufacturing a metal composite core, which includes a curing step of curing the resin of the composite magnetic material filled by the above-described filling method, is also an aspect of the present invention. [Effects of the Invention]

[0012] According to the present invention, it is possible to increase the productivity of the filling operation of the composite magnetic material and to suppress the density variation of the metal composite core. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a general configuration of a filling device according to an embodiment. [Figure 2] 1 is a cross-sectional view showing a schematic configuration of an extruder according to an embodiment. FIG. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of an injection plate. [Figure 4] FIG. 2 is a perspective view showing the overall configuration of the case. [Figure 5] FIG. 2 is a perspective view showing a schematic overall configuration of a reactor. [Figure 6] FIG. 4 is a schematic view of the cover as viewed from the central axis direction. [Figure 7] FIG. [Figure 8] 10A and 10B are schematic diagrams showing the shape of a case and the position of a cover in another embodiment. [Figure 9] 10A and 10B are schematic diagrams showing the shape of a case and the position of a cover in another embodiment. [Figure 10] 10A and 10B are schematic diagrams showing the shape of a case and the position of a cover in another embodiment. [Figure 11] 10A and 10B are schematic diagrams showing the shape of a case and the position of a cover in another embodiment. [Figure 12] 10A and 10B are schematic diagrams illustrating the configuration of a pressing portion in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Embodiment) The filling device of this embodiment will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the general configuration of the filling device of this embodiment. Fig. 2 is a cross-sectional schematic diagram showing the general configuration of the extruder of this embodiment.

[0015] The filling device 1 is a device that fills a case 3 with a composite magnetic material that constitutes a metal composite core 5 (hereinafter referred to as an "MC core"; see Figures 5 and 7). The MC core 5 is a core formed by mixing a magnetic material with a resin to create a composite magnetic material, and then hardening the resin. The MC core 5 is a component of a coil part such as a reactor 8 (see Figure 5). The composite magnetic material is a highly viscous clay-like material in which resin is added in the range of 3 wt% to 5 wt% relative to the magnetic powder. The filling device 1 includes an extruder 2, a case 3, and a cover 4.

[0016] The extruder 2 extrudes the composite magnetic material and fills it into the case 3. As shown in FIG.

[0017] The composite magnetic material is injected into the injection port 21. The injection port 21 is a cylindrical member. The injection port 21 is arranged so that the cylindrical axis of the injection port 21 is perpendicular to the central axis C of the cylindrical portion 22. The injection port 21 is arranged on the bottom surface 221 side of the cylindrical portion 22. The injection port 21 is connected to the cylindrical portion 22. The inner diameter of the injection port 21 is smallest at the point where it communicates with the cylindrical portion 22 and increases toward the top. In other words, the inner surface of the injection port 21 has an inclined shape. The up-down direction here refers to the direction perpendicular to the installation surface on which the filling device 1 is installed. The injection port 21 may be provided with a storage section for storing the injected composite magnetic material.

[0018] The cylindrical portion 22 is a bottomed cylindrical member in which only one end face perpendicular to the central axis C is open. That is, the cylindrical portion 22 has a bottom surface 221. The composite magnetic material injected from the injection port 21 flows into the cylindrical portion 22. The cylindrical portion 22 has an overhang portion 222. The overhang portion 222 is rectangular. The overhang portion 222 is provided at the tip portion of the cylindrical portion 22. The overhang portion 222 is larger than the outer diameter of the cylindrical portion 22. The overhang portion 222 has an opening of the same shape as the cylindrical portion 22, and this opening overlaps with the opening of the cylindrical portion 22.

[0019] The pressing portion 23 presses the composite magnetic material that has flowed into the cylindrical portion 22. As shown in FIG. 2 , the pressing portion 23 is provided inside the cylindrical portion 22. The pressing portion 23 has a shaft portion 231 and a rotating blade 232. The shaft portion 231 is provided to be rotatable. An example of a drive source for the shaft portion 231 is a motor. The shaft portion 231 penetrates the bottom surface 221 of the cylindrical portion 22 and extends along the central axis of the cylindrical portion 22. The shaft portion 231 extends to the vicinity of the protruding portion 222 of the cylindrical portion 22.

[0020] Rotating feathers 232 are spiral-shaped and are provided around shaft portion 231. More specifically, rotating feathers 232 move along central axis C while rotating around shaft portion 231. Rotating feathers 232 rotate in conjunction with the rotation of shaft portion 231. The outermost periphery of rotating feathers 232 is located near the inner circumferential surface of cylindrical portion 22. "Near" here means a state in which there is no gap so that rotating feathers 232 can rotate, and as long as rotating feathers 232 can rotate, rotating feathers 232 and the inner circumferential surface of cylindrical portion 22 may be in contact with each other without any gap.

[0021] The injection plate 24 is a thin plate-shaped member. The injection plate 24 is fixed to the protruding portion 222 with bolts or the like. In other words, the injection plate 24 is detachable from the protruding portion 222. The injection plate 24 closes the opening of the cylindrical portion 22.

[0022] FIG. 3 is a schematic diagram showing the configuration of the injection plate 24. The injection plate 24 has an injection area 241 that is approximately the same as the opening of the protruding portion 222. The injection plate 24 has a plurality of holes 242 within the injection area 241. The holes 242 are circular. The holes 242 are through-holes that penetrate the injection plate 24. The composite magnetic material is injected from these holes 242 to the outside of the extruder 2. In other words, the holes 242 serve as injection ports. The holes 242 are arranged on a projected area in the direction of the central axis C of the center leg covering portion 31 of the case 3, which will be described later. The shape of the holes 242 does not have to be circular, and may be rectangular, triangular, or the like.

[0023] 4 is a perspective view showing the overall configuration of the case 3. The case 3 is a member filled with a composite magnetic material. The case 3 has a cylindrical shape with both ends open. The case 3 is positioned so that the openings are perpendicular to the central axis C.

[0024] The case 3 is disposed between the injection plate 24 and the cover 4. With the case 3 sandwiched between the injection plate 24 and the cover 4, the tip of a fastener 41 erected on the injection plate 24 passes through a hole formed in the cover 4, and the passed tip is fastened with a nut or the like, thereby fixing the case 3. The case 3 has a center leg covering portion 31, four outer leg covering portions 32, and an integrated connecting covering portion 33.

[0025] When attached to the extruder 2, the center leg covering portion 31 and the outer leg covering portion 32 extend along the central axis C. The center leg covering portion 31 and the outer leg covering portion 32 are of approximately the same length. The center leg covering portion 31 is cylindrical. The center leg covering portion 31 is circular. The hole 242 of the injection plate 24 is located on the projected area of the center leg covering portion 31 in the direction of the central axis C. The center leg covering portion 31 has a larger cross-sectional area of the internal space than the outer leg covering portion 32. The cross-sectional area of the internal space refers to the area perpendicular to the central axis C.

[0026] The outer leg covering portion 32 is roughly triangular in shape. The outer leg covering portion 32 is cylindrical in shape. The four outer leg covering portions 32 are arranged at equal intervals in the circumferential direction around the center leg covering portion 31. That is, the outer leg covering portions 32 are arranged at 90-degree intervals.

[0027] The pair of connecting covering parts 33 are arranged to sandwich the center leg covering part 31 and the outer leg covering parts 32. The connecting covering parts 33 connect the center leg covering part 31 and the four outer leg covering parts 32. The connecting covering parts 33 have openings of the same shape as the openings of the center leg covering part 31 and the outer leg covering parts 32, and are connected to the internal spaces of the center leg covering part 31 and the outer leg covering parts 32. The case 3 is divided into two parts so that the coil 6 (described later) can be attached to the center leg covering part 31.

[0028] The case 3 is made of resin. Examples of the resin that can be used to form the case 3 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), and PBT (Polybutylene Terephthalate).

[0029] The case 3 is one of the components of the reactor 8. FIG. 5 is a perspective view showing a schematic overall configuration of the reactor. A coil 6 is attached to a center leg covering portion 31 of the case 3. Meanwhile, an MC core 5 made of hardened composite magnetic resin is formed in the internal space of the case 3. The case 3 serves to insulate the MC core 5 from the coil 6. Note that the case 3 does not necessarily have to be a component of the reactor 8.

[0030] Coil 6 is composed of a single conductive member that is insulated with enamel or the like. Coil 6 is formed by winding the conductive member into a cylindrical shape while shifting the winding position in the winding axis direction. The conductive member is, for example, a rectangular wire. Coil 6 is an edgewise coil in which the wide surface of the rectangular wire extends in a direction perpendicular to the winding axis of coil 6. Coil 6 may also be a flatwise coil. Furthermore, round wire may also be used as the conductive member.

[0031] The coil 6 is attached to the leg covering part having a large cross-sectional area of the internal space. In this embodiment, the coil 6 is attached to the middle leg covering part 31. A lead wire is drawn out from the coil 6. The lead wire is connected to the bus bar 7. By connecting the lead wire to the bus bar 7, power is supplied from the external device to the coil.

[0032] As shown in Fig. 1, the cover 4 covers the opening of the case 3 on the opposite side from the extruder 2. In other words, the case 3 is sandwiched between the cover 4 and the extruder 2. The cover 4 has a rectangular thin plate shape. The cover 4 is fixed to the injection plate 24 with fixing devices 41 such as bolts.

[0033] FIG. 6 is a schematic diagram of the cover 4 as viewed from the central axis direction. The cover 4 has hole regions 42. The hole regions 42 are arranged outside the projection region R of the leg portion of the MC core 5, which has a large cross-sectional area of the internal space. In this embodiment, the hole regions 42 are arranged outside the projection region R of the center leg covering portion 31. The four hole regions 42 are preferably arranged at positions farthest from the holes 242 of the injection plate 24. In other words, the hole regions 42 are preferably arranged at positions farthest from the projection region R of the center leg covering portion 31. Four hole regions 42 are provided. The four hole regions 42 are provided at each vertex of the rectangular cover 4 that is farthest from the projection region R of the center leg covering portion 31, and correspond to the positions of the outer leg covering portions 32.

[0034] The cover 4 has holes 43. The holes 43 are through-holes that penetrate the cover 4. The holes 43 are formed within the hole regions 42. A plurality of holes 43 are formed in one hole region 42. The holes 43 are circular. The area of one hole 43 is smaller than the cross-sectional area of the internal space of the outer leg covering portion 32.

[0035] Next, the composite magnetic material and the MC core 5 will be described. The composite magnetic material is composed of magnetic powder and resin. As the magnetic powder, soft magnetic powder can be used, and in particular, Fe powder, Fe-Si alloy powder, Fe-Al alloy powder, Fe-Si-Al alloy powder (Sendust), amorphous alloy powder, nanocrystal, or a mixture of two or more of these powders can be used. As the Fe-Si alloy powder, for example, Fe-6.5% Si alloy powder or Fe-3.5% Si alloy powder can be used.

[0036] The magnetic powder may be magnetic powders with different average particle diameters. In other words, the magnetic powder may be composed of a first powder and a second powder with a smaller average particle diameter than the first powder. In this specification, the average particle diameter refers to D50 (median diameter) unless otherwise specified. Furthermore, the first powder and the second powder may be the same or different types.

[0037] The average particle size of the first powder is preferably 100 μm or more and 200 μm or less, and that of the second powder is preferably 3 μm or more and 10 μm or less. By setting the sizes in these ranges, the second powder, which has a smaller average particle size, can fill the gaps between the first powder particles, thereby improving density and magnetic permeability and reducing iron loss.

[0038] The resin is mixed with the magnetic powder to hold the magnetic powder in place. The resin can be a thermosetting resin, a UV-curable resin, or a thermoplastic resin. The thermosetting resin can be a phenolic resin, an epoxy resin, an unsaturated polyester resin, a polyurethane, a diallyl phthalate resin, or a silicone resin. The UV-curable resin can be a urethane acrylate, an epoxy acrylate, an acrylate, or an epoxy resin. The thermoplastic resin is preferably a resin with excellent heat resistance, such as polyimide or fluororesin.

[0039] The resin content is set to 3 wt% or more and 5 wt% or less relative to the magnetic powder. If the resin content is less than 3 wt%, the composite magnetic material will have a dry, powdery texture and poor fluidity, making it difficult to fill the case 3 using the extruder 2. Furthermore, the bonding strength of the magnetic powder will be insufficient, reducing the mechanical strength of the MC core. On the other hand, if the resin content is greater than 5 wt%, the viscosity will decrease, and the resin contained in the composite magnetic material may leak from the case 3. Furthermore, the density of the MC core will decrease, and the magnetic permeability will decrease, as the magnetic powder will no longer be able to be held without gaps. If the resin content is set to 3 wt% or more and 5 wt% or less, the viscosity of the composite magnetic material will increase, reaching a range that would previously have required manual filling. However, the filling device 1 of this embodiment makes it possible to fill the case 3 using the extruder 2.

[0040] The MC core 5 is made of hardened composite magnetic resin. The MC core 5 is used as the magnetic body of the reactor 8. FIG. 7 is an exploded perspective view of the reactor 8. For ease of explanation, the coil 6 is not shown in FIG. 7. The MC core 5 has a shape similar to that of the case 3.

[0041] The MC core 5 has a center leg portion 51, outer leg portions 52, and a connecting portion 53. The coil 6 is attached to the center leg portion 51. The center leg portion 51 is covered by the center leg covering portion 31. That is, the center leg covering portion 31 insulates the center leg portion 51 from the coil 6. The center leg portion 51 is circular.

[0042] The outer legs 52 are arranged around the center leg 51. Four outer legs 52 are provided. The four outer legs 52 are arranged at equal intervals of 90 degrees around the center leg 51. The outer legs 52 are roughly triangular in shape. A pair of connecting portions 53 are provided. The pair of connecting portions 53 sandwich the center leg 51 and the outer legs 52. They connect the center leg 51 and the four outer legs 52. The center leg 51, outer legs 52, and connecting portion 53 are formed as a single, seamless piece.

[0043] (Manufacturing method) Next, we will explain the method for filling the composite magnetic material and the method for manufacturing the MC core 5. The method for filling the composite magnetic material of this embodiment includes a composite magnetic material preparation step, an attachment step, an injection step, and a filling step. Furthermore, the method for manufacturing the MC core 5 further includes a curing step in addition to the steps of the method for filling the composite magnetic material.

[0044] The composite magnetic material preparation process is a process in which 3 wt% to 5 wt% of resin is added to magnetic powder and mixed with the resin. The magnetic powder and resin are mixed automatically or manually using any mixer. The mixing time can be set appropriately, but is, for example, 10 minutes. A composite magnetic material is produced through the composite magnetic material preparation process.

[0045] The mounting step is a step of mounting the case 3 and cover 4 to the extruder 2. The connecting covering portion 33 of the case 3 is placed opposite the injection plate 24 of the extruder 2, and the connecting covering portion 33 and the injection plate 24 are brought into contact. At this time, the case 3 is fixed so that the hole 242 of the injection plate 24 is positioned on the projected area of the center leg covering portion 31 of the case 3. Then, each hole area 42 of the cover 4 covers the opening of the case 3 so that it corresponds to the position of each outer leg covering portion 32 of the case 3. In this state, the cover 4 is fixed to the injection plate 24 with fasteners 41 such as bolts. In this embodiment, the coil 6 is wound around the case 3 in a stage prior to the mounting step, and the case 3 with the coil 6 is attached to the extruder 2.

[0046] Either the composite magnetic material preparation step or the mounting step may be performed first. That is, the mounting step may be performed first, followed by the composite magnetic material preparation step. Also, the composite magnetic material preparation step and the mounting step may be performed simultaneously in parallel.

[0047] The injection step is a step of injecting the composite magnetic material produced in the composite magnetic material step into the extruder 2. In the injection step, the composite magnetic material is injected into the injection port 21 of the extruder 2.

[0048] The filling step is a step in which the composite magnetic material is filled into the case 3 by the extruder 2. The composite magnetic material injected in the injection step flows into the cylindrical portion 22 through the injection port 21. When the motor is driven in this state, the shaft portion 231 of the pressing portion 23 rotates. When the shaft portion 231 rotates, the rotating feathers 232 also rotate, and the composite magnetic material in the cylindrical portion 22 is carried toward the injection plate 24. The pressing force in the filling step is changed as appropriate depending on the viscosity of the composite magnetic material, but is preferably at least 5 MPa or more.

[0049] There is no gap between the outermost periphery of the rotary vanes 232 and the inner periphery of the cylindrical portion 22. Therefore, the composite magnetic material is transported to the injection plate 24 side without accumulating in the cylindrical portion 22. The composite magnetic material transported to the injection plate 24 side is pushed out through the holes 242 of the injection plate 24 and flows into the case 3.

[0050] Because the hole 242 is located on the projected area of the center leg cover 31 of the case 3, the composite magnetic material flows into the internal space of the center leg cover 31. The composite magnetic material that flows into the internal space of the center leg cover 31 reaches the connecting cover 33. The connecting cover 33 is covered with the cover 4, and the hole area 42 of the cover 4 is located outside the projected area R of the center leg cover 31 around which the coil 6 is wound. Therefore, the composite magnetic material that reaches the connecting cover 33 hits the cover 4 in a portion where the hole 43 is not formed and spreads into the internal space of the connecting cover 33. At this point, the composite magnetic material is not extruded from the hole 43.

[0051] The composite magnetic material that reaches the connecting covering portion 33 gradually fills the internal space of the connecting covering portion 33. Because the area of one hole 43 in the cover 43 is smaller than the cross-sectional area of the internal space of the outer leg covering portion 32, the composite magnetic material that fills the internal space of the connecting covering portion 33 easily flows into the internal space of the outer leg covering portion 32. Therefore, even at this point, the composite magnetic material is difficult to extrude from the hole 43 in the cover 43, and begins to flow into the internal space of the outer leg covering portion 32. The composite magnetic material that has flowed into the internal space of the outer leg covering portion 32 is extruded toward the extruder 2, reaches the connecting covering portion 33 on the extruder 2 side, and fills the space of the connecting covering portion 33.

[0052] When all the spaces in the center leg covering portion 31, the four outer leg covering portions 32, and the pair of connecting covering portions 33 are filled with the composite magnetic material, the composite magnetic material is extruded from the hole 43 in the cover 4. This signals the motor to be stopped, the rotation of the shaft portion 231 and the rotating blades 232 to be stopped, and the filling process is completed.

[0053] The curing step is a step of curing the resin of the composite magnetic material filled in the case 3. First, the case 3 is removed from the extruder 2. Then, the process proceeds to the step of curing the resin. When the resin is cured by drying, the drying atmosphere can be an air atmosphere. The drying time can be appropriately changed depending on the type of resin, content, drying temperature, etc., and can be, for example, 1 to 4 hours, but is not limited to this. The drying temperature can be appropriately changed depending on the type of resin, content, drying time, etc., and can be, for example, 85°C to 150°C, but is not limited to this. The drying temperature is the temperature of the drying atmosphere.

[0054] Furthermore, the curing method of the resin is not limited to drying, and varies depending on the type of resin. For example, if the resin is a thermosetting resin, the resin is cured by applying heat, and if the resin is an ultraviolet-curable resin, the resin is cured by irradiating the molded body with ultraviolet light.

[0055] In the curing step, the step of curing the resin may be repeated multiple times. For example, when the resin is cured by drying, the drying temperature or drying time may be changed each time the step is repeated. The MC core 5 is produced through the curing step.

[0056] (effect) As described above, the filling device of this embodiment includes extruder 2 that extrudes a composite magnetic material, cylindrical case 3 that is attached to extruder 2 and filled with the composite magnetic material extruded from extruder 2, and cover 4 that closes the opening of case 3. Extruder 2 has cylindrical portion 22 into which the composite magnetic material is injected, and pressing portion 23 that is provided inside cylindrical portion 22 and extrudes the composite magnetic material toward case 3. The outermost peripheral portion of pressing portion 23 is located near the inner peripheral surface of cylindrical portion 22, and cover 4 has holes 43. The resin that constitutes the composite magnetic material is contained in a range of 3 wt % to 5 wt % with respect to the magnetic powder.

[0057] This makes it possible to fill even highly viscous composite magnetic materials into the case 3 using the filling device 1, thereby increasing the productivity of the filling work. Furthermore, because filling is done by machine, density variations in the MC core 5 can be reduced compared to manual filling, resulting in stable characteristics of the coil component.

[0058] Furthermore, case 3 is one of the components of reactor 8, serving as an insulating member that insulates MC core 5 from coil 6. This eliminates the need for a process for covering MC core 5 with an insulating member after manufacturing MC core 5, thereby improving productivity.

[0059] Furthermore, the cover 4 has a hole 43. The composite magnetic material extruded by the extruder 2 is injected at a higher pressure than when extruded manually. Therefore, if the cover 4 does not have the hole 43, the internal pressure in the case 3 increases, which may result in damage to the case 3. However, by providing the hole 43 in the cover 4 as in this embodiment, the increase in internal pressure in the case 3 can be suppressed, and damage to the case 3 can be prevented.

[0060] The case 3 has a center leg covering portion 31 and an outer leg covering portion 32 extending along the central axis direction of the cylindrical portion 22, and the cross-sectional area of the internal space of the center leg covering portion 31 is larger than the cross-sectional area of the outer leg covering portion 32. The extruder 2 has a hole 242 which is an injection port for injecting the composite magnetic material toward the center leg covering portion 31, and the holes 43 of the cover 4 are provided in hole regions 42 at the four corners of the cover 4 which are outside the projected area R in the central axis direction of the center leg covering portion 31.

[0061] In this way, the hole 43 of the cover 4 is formed at a position away from the injection port. Therefore, the composite magnetic material is last filled in the space near the hole 43 within the case 3. Therefore, the composite magnetic material being pushed out from the hole 43 signals that the composite magnetic material has been filled into every corner of the case 3, improving the efficiency of the filling work.

[0062] Furthermore, multiple holes 242 are formed in one hole region 42. If a single large hole were formed in one hole region 42, there is a risk that the composite magnetic material would be pushed out of the hole before it could be filled to every corner of the case 3. However, by forming multiple holes 43 in one hole region 42 with the same hole area as a single large hole, the composite magnetic material is prevented from being pushed out of the hole 43 before it can be filled to every corner of the case 3. Furthermore, by forming multiple holes 242, the injection pressure can be increased compared to when a single large hole with the same area is formed. As a result, the composite magnetic material can be filled to every corner of the case 3.

[0063] (Example) The present invention will be described in more detail based on examples. However, the present invention is not limited to the following examples. MC cores of Example 1 and Comparative Examples 1 and 2 were produced. The MC cores of Example 1 and Comparative Examples 1 and 2 were produced using the same materials, under the same conditions, and by the same method, except for the method of filling the composite magnetic material.

[0064] First, a composite magnetic material was produced. Two types of magnetic powder with different average particle sizes were used. Fe-6.5Si alloy powder was used for both the first and second powders. The average particle size of the first powder was 150 μm, and the average particle size of the second powder was 8 μm. The content ratio of the first powder to the second powder was 70:30. Epoxy resin was used as the resin. 3.75 wt% of the resin was added to the soft magnetic powder. After mixing the first powder and the second powder, further resin was mixed to obtain a composite magnetic material.

[0065] Next, the composite magnetic material was filled into the case 3. The shape of the case 3 was the same as that described in the above embodiment. In the example, the case 3 was attached to the extruder 2, and the composite magnetic material was filled into the case 3 using the filling device 1. On the other hand, in the comparative example 1, the filling was done manually by an operator without using a machine such as the filling device 1. In the comparative example 2, the operator filled the case manually, and then pressurized. The pressure was 5 kgf.

[0066] After filling the case with the composite magnetic material, the resin of the composite magnetic material was cured at 150°C for 3 hours. Through these steps, 10 MC cores each of the example and comparative examples 1 and 2 were produced.

[0067] The density of each MC core was measured. The density is the apparent specific gravity / volume, and a measurement sample cut out from each MC core was measured by Archimedes' method. Specifically, the measurement was performed as follows.

[0068] (1) Dry the sample in a thermostatic chamber at 110°C, and measure the mass (dry weight) when cooled to room temperature. (2) After measuring the dry weight, submerge the sample in water until saturated, and measure the mass (underwater weight) while it is still suspended in the water by the wire (excluding the mass of the jig such as the wire). (3) Calculate the apparent specific gravity calculated using the following formula (1). (Equation 1) Apparent specific gravity = dry weight / (dry weight - weight in water) (1) (4) Calculate the density from the apparent specific gravity and the volume of the sample.

[0069] The results are shown in Table 1 below.

[0070] [Table 1]

[0071] As shown in Table 1 above, the average density of the examples is 5.85 (g / cm 3 ), which is a higher value compared to the average density of Comparative Examples 1 and 2. In addition, the CV value of the example was 0.0120, which is a lower value than the CV values of Comparative Examples 1 and 2. Therefore, it was confirmed that filling the composite magnetic material using the filling device 1 can achieve higher density and reduce density variation compared to manual filling.

[0072] Furthermore, a reactor was fabricated using this MC core 5, and iron loss was measured. The iron loss measurement conditions were as follows: 1) a coil 6 was wound 33 turns around the center leg 51 (center leg sheath 31 of the case) of each MC core; 2) a 5 kHz sinusoidal current was passed through the coil 6, and the reactor loss (W) was measured using a power meter (Yokogawa Electric Corporation: WT3000E) at current values where the magnetic flux density was 10 mT and 80 mT. 3) The coil loss, calculated from the coil's DC resistance and current value, was subtracted from the measured reactor loss, and the result was taken as iron loss.

[0073] The results are shown in Table 2 below.

[0074] [Table 2]

[0075] As shown in Table 2 above, in both cases where the maximum magnetic flux density Bm was 10 mT and 80 mT, the loss in the example was reduced to less than half of that in comparative example 1 and to about 60% of that in comparative example 2. Therefore, it was confirmed that the iron loss of the reactor was significantly reduced when the composite magnetic material was filled using the filling device 1.

[0076] (Other embodiments) Although the present specification describes an embodiment of the present invention, this embodiment is presented as an example and is not intended to limit the scope of the invention. The above-described embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0077] In the above embodiment, the case 3 has the center leg covering portion 31 and four outer leg covering portions 32, but the shape of the case 3 is not limited to this. As shown in Fig. 8, there may be two outer leg covering portions 32. In this case, the two outer leg covering portions 32 are arranged so that the center leg covering portion 31, on which the coil 6 is attached, is sandwiched between them. The hole regions 42 of the cover 4 are provided at the four corners of the cover 4 that are outside the projection region R of the center leg covering portion 31.

[0078] 9, the inner circumferential surfaces of the two outer leg covering parts 32 facing the coil 6 may have a shape that follows the shape of the coil 6. In this case as well, the hole areas 42 of the cover 4 are provided at the four corners of the cover 4 that are outside the projection area R of the middle leg covering part 31.

[0079] Furthermore, the case 3 may not have a center leg covering portion 31 and may be composed of only two outer leg covering portions 32, as shown in Fig. 10. The coil 6 is attached to each of the outer leg covering portions 32. In this case, the hole area 42 of the cover 4 is located outside the projected area R of the outer leg covering portion 32 to which the coil 6 is attached. More specifically, it is preferable to provide two hole areas 42, one above the other and one below the center portion between the outer leg covering portions 32. In this case, the emission areas 241 of the emission plate 24 are each provided in the projected area R of the outer leg covering portion 32 to which the coil 2 is attached.

[0080] 11, the coil 6 may be attached to only one of the two outer leg covering parts 32. In this case, too, it is preferable to provide the coil 6 at two locations above and below the center portion between the outer leg covering parts 32, just as in the case where the coil 6 is attached to each of the two outer leg covering parts 32.

[0081] In the above embodiment, the pressing unit 23 is configured with the shaft 231 and the rotary vanes 232. However, the configuration of the pressing unit 23 is not limited to this. The pressing unit 23 may have a piston structure. For example, as shown in FIG. 12 , the pressing unit 23 has a shaft 233 and a push-out unit 234. The shaft 233 penetrates the bottom surface 221 of the cylindrical unit 22 and extends along the central axis C. The shaft 233 is provided to be movable along the central axis C. The push-out unit 234 is attached to the tip of the shaft 233 and moves in conjunction with the shaft 233. The outermost periphery of the push-out unit 234 is located near the inner circumferential surface of the cylindrical unit 22. By configuring the pressing unit 23 in this manner and moving the pressing unit 23 along the central axis, the composite magnetic material that has flowed into the cylindrical unit 22 can be pushed out through the hole 242 of the injection plate 24. [Explanation of symbols]

[0082] 1 Filling device 2. Extruder 21 Inlet 22 Cylindrical part 221 bottom 222 Overhang 23 Pressing section 231 Shaft 232 Rotating Blade 233 Shaft 234 Extrusion section 24 Injection plate 241 Injection area 242 holes 3 Cases 31 Middle leg covering 32 Outer leg covering 33 Connecting cover part 4 Cover 41 Fixtures 42 hole area 43 holes 5 Metal composite core (MC core) 51 Middle leg 52 External legs 53 Connecting part 6 coils 7 Busbar 8 Reactor C center axis

Claims

1. A filling device that fills a composite magnetic material that constitutes a metal composite core formed by mixing a resin and a magnetic powder and hardening the resin, an extruder that extrudes the composite magnetic material; a cylindrical case attached to the extruder and filled with the composite magnetic material extruded from the extruder; a cover that closes the opening of the case; Equipped with The extruder a cylindrical portion into which the composite magnetic material is injected; a pressing portion provided inside the cylindrical portion and configured to push the composite magnetic material toward the case; and an outermost peripheral portion of the pressing portion is located near an inner peripheral surface of the cylindrical portion; the cover has a hole; The resin constituting the composite magnetic material is contained in an amount of 3 wt % or more and 5 wt % or less with respect to the magnetic powder; A filling device characterized by:

2. the case has a plurality of leg covering portions extending along the central axis direction of the cylindrical portion, At least one of the plurality of leg covering portions has an internal space with a cross-sectional area larger than that of the other leg covering portions, the extruder has an injection port that injects the composite magnetic material toward the leg covering portion having the large cross-sectional area, the hole is provided in a hole region that is outside a projected region in the central axis direction of the leg covering portion having the large cross-sectional area; 2. The filling device according to claim 1, wherein:

3. a plurality of the holes are formed in the hole region; 3. The filling device according to claim 2, wherein:

4. a composite magnetic material preparation step of mixing magnetic powder and resin to prepare a composite magnetic material; an injection step of injecting the composite magnetic material into a filling device; a filling step of filling the composite magnetic material into a cylindrical case; Including, The filling device is a cylindrical portion into which the composite magnetic material is injected; a pressing portion provided inside the cylindrical portion and configured to push the composite magnetic material toward the case; and an opening of the case opposite to the opening where the composite magnetic material is filled is closed with a cover; the cover has a hole; In the composite magnetic material preparation step, the resin is added to the magnetic powder in an amount of 3 wt % or more and 5 wt % or less to prepare a clay-like composite magnetic material; in the filling step, an outermost portion of the pressing portion is located near an inner peripheral surface of the cylindrical portion, and the pressing portion pushes out the composite magnetic material that has flowed into the cylindrical portion toward the case; A method for filling a composite magnetic material, characterized by:

5. the case has a plurality of leg covering portions extending along the central axis direction of the cylindrical portion, At least one of the plurality of leg covering portions has an internal space with a cross-sectional area larger than that of the other leg covering portions, the hole is provided in a hole region that is outside a projected region in the central axis direction of the leg covering portion having the large cross-sectional area, In the filling step, the pressing portion pushes the composite magnetic material into the case toward the leg covering portion having the larger cross-sectional area.

5. The method for filling a composite magnetic material according to claim 4,

6. a plurality of the holes are formed in the hole region; 6. The method for filling a composite magnetic material according to claim 5,

7. The method according to any one of claims 4 to 6 further includes a curing step of curing the resin of the composite magnetic material filled in the case. A method for manufacturing a metal composite core, characterized by:

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