JP2006032663A - Inductor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive inductor which has high inductance, even in a large current and has low-DC resistance and which is small-sized and low in height with a high occupation rate of a coil, and to provide its manufacturing method. <P>SOLUTION: The inductor includes in combination first and second flat plate-shaped magnetic cores 2, the coil 14, and a rare-earth bond magnet 3. The coil 14 is formed by winding spirally a flat square conducting wire as a first layer and further winding the flat square conducting wire, that is at that time located on an inner periphery side, on the first layer winding spirally to provide a second layer overlapping it from the inner peripheral side to an outer peripheral side. The rare-earth bond magnet 3 is installed on at least one of the inner peripheral side or outer peripheral side of the coil oppositely to a magnetic field generated by the coil 14 so as to apply a magnetic bias. The coil 14 and the rare-earth bond magnet 3 are sandwiched between the first and second magnetic cores 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inductor suitable for use as a smoothing inductor product or a noise countermeasure inductor product used in various power supply devices, communication / information-related devices, and the like, and a method of manufacturing the same.

  A conventional example of this type of inductor is shown in FIG. 4A is an exploded perspective view thereof, and FIG. 4B is an assembly view thereof. A so-called edgewise coil 4 that winds a flat conducting wire around a cylindrical winding jig for two or more turns has a columnar middle leg, and has an EI or EE shape or pot core shape magnet with a gap in the middle leg. It was incorporated in the core 5. For this reason, when reducing the height of the product, the aspect ratio of the flat wire with respect to the center diameter of the winding has a limit value that does not cause damage to the coating.

  FIG. 5 shows another conventional inductor. FIG. 5A is a cross-sectional view thereof, and FIG. 5B is a plan view of a coil used therefor. In this example, a round conducting wire is wound around a winding core in a spiral layer and fused to form a winding start end portion 7a and a winding end end portion 7b as terminals. The whole of the combination of the coil and the terminal block is fixed in the terminal embedded in the base and mounted in the magnetic core 6 to form an inductor. Therefore, the thickness of the terminal block not only hinders the low profile, but also the winding start end pulled out from the inner peripheral side has a thickness of one layer, resulting in a poor space factor. It was.

  FIG. 6 is a sectional view showing another conventional inductor. In this example, wiring pattern-shaped coils 9 are formed on both surfaces of the substrate portion 8, and the entire wiring pattern-shaped substrate coil is mounted in the magnetic core 10 to form an inductor. Due to the thickness of the substrate, the space factor deteriorated, which was an obstacle to low profile.

  The inductor disclosed in Patent Document 1 is shown in a perspective view in FIG. In this case, the metal conductor 12 is formed as a one-turn linear coil, and the inductor is formed by combining the coil with the resin 13 and the first and second magnetic cores 11. In that case, the inductance value cannot be increased because the number of turns of the coil is small.

  Furthermore, there is a conventional example of a drum choke. In this case, however, if a low-profile type is used, windings are formed on the core by cutting, which makes it difficult to reduce costs.

JP 2000-323336 A

  Under the circumstances described above, an object of the present invention is to provide an inexpensive inductor and a method for manufacturing the same that have a high inductance value even at a large current, a small size, a low profile, and a high coil space factor.

  In order to solve the above-described problems, an inductor according to a first invention includes a flat plate-like first magnetic core, a coil, and a 2-17 type Sm—Co system, Nd—Fe—B system, or Sm—Fe—N. In the inductor comprising a combination of a rare earth magnet powder based resin and a plate-like second magnetic core, the coil is wound as a first layer in a spiral shape with a rectangular conductor having a square cross section, A flat rectangular wire is wound on the first layer winding from the inner periphery side to the outer periphery side, and spirally wound so as to be the second layer. At least one of the coupling bodies is installed so as to apply a magnetic bias in a direction opposite to the magnetic field generated by the coils, and the coils and the coupling bodies are sandwiched between the first and second magnetic cores. It is characterized by that.

  An inductor according to a second invention is the inductor according to the first invention, wherein the combined body is a bonded magnet.

  An inductor according to a third invention is characterized in that, in the inductor according to the first invention, the combined body is formed by solidifying a resin paste containing rare earth magnet powder.

  The inductor of the fourth invention is the inductor of any one of the first to third inventions, wherein the end of the flat wire at the beginning of winding of the coil and the end of the flat wire at the end of winding are bent and bent. The tip of the processed part is formed as an external mounting terminal.

  An inductor according to a fifth aspect of the invention is the inductor according to any one of the first to third aspects, wherein the end of the flat wire at the beginning of winding of the coil and the end of the flat wire at the end of winding are on the outer surface of the magnetic core. The tip portion is arranged on the bottom surface of the magnetic core.

  An inductor according to a sixth aspect is the inductor according to the fourth or fifth aspect, wherein the tip is crushed by pressing.

  An inductor according to a seventh aspect is the inductor according to any one of the first to sixth aspects, wherein the coil is molded with an insulating resin, and is incorporated between the first magnetic core and the second magnetic core together with the combined body. It is characterized by that.

  The inductor of the eighth invention is made of a plate-like first magnetic core, a coil, and a resin of a 2-17 type Sm—Co, Nd—Fe—B, or Sm—Fe—N rare earth magnet powder. In an inductor formed by combining a combined body and a flat plate-like second magnetic core, the coil is formed by connecting a plurality of unit coils, and the unit coil has a rectangular conductor as a first layer in a spiral shape. Winding and winding the rectangular conductor wire on the inner circumference side on the first layer winding from the inner circumference side to the outer circumference side and winding in a spiral shape so as to become the second layer. The coupling body is disposed on at least one of the circumferential side and the outer circumferential side so as to apply a magnetic bias in a direction opposite to the magnetic field generated by the coil, and the coil and the coupling body include the first and second magnetic cores. Sandwiched between And wherein the door.

  According to a ninth aspect of the present invention, there is provided an inductor manufacturing method comprising: a flat plate-like first magnetic core; a coil; and a 2-17 type Sm-Co-based, Nd-Fe-B-based, or Sm-Fe-N-based rare earth magnet powder. In a method of manufacturing an inductor comprising a combination of a resin and a flat second magnetic core, a rectangular conductor having a rectangular cross section is spirally wound around a winding core to form a first layer winding, A step of superimposing a flat rectangular conductor wire on the inner circumference side on the first layer winding from the inner circumference side to the outer circumference side and winding it in a spiral shape on the second layer to produce the coil; and the coil And applying the resin paste of the rare earth magnet powder to at least one of the inner peripheral side and the outer peripheral side, and combining them so as to be sandwiched between the first and second magnetic cores, and the direction opposite to the magnetic field generated by the coil Magnetic bias applied to Characterized in that it comprises a step of orienting said rare earth magnet powder after application as.

  An inductor manufacturing method according to a tenth invention is the inductor manufacturing method according to the ninth invention, wherein the step of orienting the rare earth magnet powder is performed by applying a pulse current in a direction opposite to a coil energizing direction at the time of use. The method of manufacturing an inductor according to claim 9, wherein the inductor manufacturing step is performed.

  In the inductor of the present invention, a coil is efficiently installed in a space between two flat magnetic cores, and the space factor of the coil is increased. That is, since a bobbin or the like is unnecessary, the outer shape of the coil is small and the cross-sectional area of the coil conductor is large. As a result, the entire inductor can be reduced in size, and a small and low-profile inductor with low DC resistance and high inductance can be realized. In the present invention, since the bonded magnet is installed on at least one of the inside and the outside of the coil, the DC superimposition characteristics can be improved.

  In the present invention, the coil is molded with an insulating resin, and a bond magnet is installed on at least one of the inside and outside of the molded coil, or a paste-like magnet is applied. Insulation between them is high, can be used in various mounting conditions, has excellent DC superimposition characteristics, and has a high inductance value.

  Further, as the external mounting terminal, the end portion of the flat rectangular wire can be bent or pressed to provide an external connection terminal suitable for the demand for higher density of the board mounting components.

  When using a magnet that has been solidified from the pasty state, the magnet is oriented by applying a pulse current in the direction opposite to the magnetic field generated by the coil during use, that is, in the direction opposite to the direction in which the coil is energized. Can be oriented and manufactured.

  In addition, since the inductor of the present invention has a simple structure, an inexpensive product can be provided.

  As described above, according to the present invention, it is possible to improve the space factor of the coil, to cope with a large current with a high inductance, to provide a small, low-profile and inexpensive inductor with a low DC resistance and a method for manufacturing the same.

  Next, embodiments of the present invention will be described with reference to the drawings. 1 shows an inductor and a coil thereof according to Embodiment 1 of the present invention, FIG. 1 (a) is a sectional view of the whole inductor, FIG. 1 (b) is a perspective view of the coil, and FIG. 1 (c) is a coil. FIG. 1D is a cross-sectional view of the coil. 2 also shows the inductor according to the first embodiment of the present invention, FIG. 2 (a) is an external perspective view, FIG. 2 (b) is an internal perspective view from above, and FIG. 2 (c) is an internal view from the front. FIG. 2D is a perspective view as seen from the front side.

  As shown in FIG. 1B, the coil 14 is formed by winding a rectangular copper wire in a spiral shape, and the central portion of the coil 14 is an air-core portion. In addition, as shown in FIGS. 1C and 1D, the coil is formed by winding a rectangular copper wire in a first layer in a spiral shape and a rectangular copper wire on the inner periphery side in the first layer. On the other winding, it is configured to be wound in a spiral shape so as to be a second layer, overlapping from the inner peripheral side to the outer peripheral side. Here, 1a is the winding start end, and 1b is the winding end.

  On the other hand, as shown in FIG. 1A and FIG. 2, the first and second magnetic cores 2 are flat ferrite cores, and rare earth bonded magnets 3 are installed inside and outside the two-layer coil 14. Alternatively, a paste-like rare earth magnet is applied, sandwiched between the first and second magnetic cores 2 and combined to form an inductor. As this rare earth magnet, a 2-17 type Sm-Co-based, Nd-Fe-B-based or Sm-Fe-N-based magnet is used. Further, the winding start end 1a and the winding end end 1b of the coil 14 are bent. Further, the tip portion may be crushed by a press. Further, the winding start end 1a and the winding end end 1b may be bent toward the product side along the outer surface of the magnetic core so that the tips of the winding end end 1b are installed on the bottom surface of the magnetic core.

  Next, an external perspective view of the inductor according to the second embodiment of the present invention is shown in FIG. The coil used for this inductor has the same shape as the coil of the first embodiment, and the winding start end 1a and winding end end 1b of the coil made of a flat copper wire are bent, and the entire coil is molded with an insulating resin. Has been. This is an inductor in which a rare earth bonded magnet 3 is installed on at least one of the inner side (the inner side of the coil) or the outer side of the molded body 15 and is incorporated between the first and second magnetic cores 2. Moreover, you may form the magnet similar to this rare earth bond magnet 3 by apply | coating the resin paste containing rare earth magnet powder. Here, the surface of the bent portion is exposed from the molded body 15, and this bent portion is directly used as an external mounting terminal.

  The inductor according to the third embodiment of the present invention is an inductor in which a plurality of coils 14 shown in FIG. 1B or FIG. 2B are installed and incorporated in the first magnetic core and the second magnetic core. Yes (not shown). As a result, an inductor with enhanced functions can be provided.

  Next, an example is given and it demonstrates in detail. The structure of the inductor of Example 1 is the same as that of Embodiment 1 shown in FIGS. The flat magnetic core 2 has two flat Ni—Zn ferrite cores having dimensions of 3 mm × 3 mm × 0.3 mm (thickness), and the coil 14 has a rectangular shape having a cross section of 0.2 mm × 0.15 mm. A copper wire is formed with two turns centering on a core of 1.2 mm × 1.2 mm, and four turns are formed in one layer for a total of 8 turns, and 2-17 type Sm is formed inside and outside the coil composed of the two layers. A Co-based rare earth bonded magnet 3 was installed and sandwiched between flat ferrite magnetic cores 2 to form inductors.

  As a result, a characteristic of about 2.1 μH is obtained at a direct current I = 0.5 A. When the magnet of the first embodiment is used, the direct current value is improved by about 40% compared to the conventional example, and I = 0. DC superposition characteristics can be secured up to 7A. As described above, in the first embodiment, the direct current value is improved with an emphasis on the direct current superposition characteristics. However, when the direct current value is not so much prioritized, the inductance value can be further increased.

  The second embodiment is an example in which improvement of the inductance value is more important than the current value of the DC superimposition characteristic. The flat magnetic core has two flat Ni—Zn ferrite cores with dimensions of 3 mm × 3 mm × 0.3 mm (thickness), and the coil has a rectangular conductor having a cross section of 0.2 mm × 0.15 mm. A total of 8 turns are formed in one layer so that there are two layers around a core of 1.2 mm × 1.2 mm, and sandwiched between two flat ferrite cores to form an inductor. At this time, when the shape, size and arrangement position of the rare earth bonded magnet are optimized and sandwiched between two flat ferrite cores to form an inductor, a characteristic of about 10.5 μH is obtained at a direct current I = 0.5 A. Obtained. When the magnet of Example 2 is used, the DC current value is improved by about 20% compared to the conventional example, and the DC superposition characteristic can be secured up to I = 0.6A. The above values are examples, and various variations of inductors can be manufactured by changing the number of turns of the coil as well as selecting the magnet.

  In the following, the features of the inductor product according to the present invention, the manufacturing method, etc. will be supplemented.

  Since the product according to the present invention can be easily made into a surface mounting type, it can be continuously mounted by packaging it on a reel.

  The components constituting the inductor of the present invention are mainly composed of a magnetic core and a coil and a bonded magnet or a magnet solidified from a paste, and the number of components is mainly three. It is characteristic that the number of parts is small and products can be provided at low cost. For example, the cost can be reduced by about 40% as compared with a low-profile drum choke.

  In the actual manufacturing process, the magnetic cores may be fixed to each other by performing adhesive fixing, holder fixing, or tape fixing to a set of magnetic cores. Also, an adhesive may be applied between the coil and the core.

  In addition, when using a conductive wire with a film such as polyimide or modified epoxy acryl having no pinhole in the conductive wire, a Mn—Zn ferrite core having a high electrical conductivity may be used. In this case, a product in which the DC current superimposition characteristic is not saturated to a large current can be manufactured compared to the Ni—Zn ferrite core. Alternatively, a product with a high inductance value can be obtained.

  In addition, when a conductive pattern is formed on the substrate on the bottom of an inductor product or when conductive parts are installed around the product, a coil-core is used as a product to prevent a short circuit between the coil and the pattern. It is necessary to secure insulation between them, but as a countermeasure in that case, the coil portion is molded in advance with an insulating resin. In this case, a magnetic core of Mn—Zn ferrite having high conductivity but excellent direct current superposition characteristics can be used.

  Also, when using a magnet that has been solidified from the paste state, the magnet can be oriented by applying a pulse current in a direction opposite to the magnetic field generated by the coil, that is, the direction in which the coil is energized. .

FIG. 1A is a cross-sectional view of the whole inductor, FIG. 1B is a perspective view of the coil, and FIG. 1C is a plan view showing a procedure for winding the coil. FIG.1 (d) is sectional drawing of a coil. FIG. 2 (a) is an external perspective view, FIG. 2 (b) is an internal perspective view from above, FIG. 2 (c) is an internal perspective view from the front, and FIG. 2 (d) is a front view. Sectional view seen from the side. The external appearance perspective view of the inductor of Embodiment 2 of this invention. 4A shows a conventional inductor, FIG. 4A is an exploded perspective view thereof, and FIG. 4B is an assembly view thereof. FIG. 5A is a cross-sectional view of another conventional inductor, and FIG. 5B is a plan view of a coil used therefor. Furthermore, sectional drawing which shows the inductor of another prior art example. The perspective view which shows the inductor of another prior art example.

Explanation of symbols

1a, 7a Winding end portion 1b, 7b Winding end portion 2, 5, 6, 10, 11 Magnetic core 3 Rare earth bonded magnet 4 Edgewise coil 8 Substrate 9 Wiring pattern coil 12 Metal conductor 13 Resin 14 Coil 15 Mold Compact

Claims (10)

  A flat first magnetic core, a coil, a 2-17-type Sm-Co-based, Nd-Fe-B-based, or Sm-Fe-N-based rare earth magnet powder bonded body, and a plate-shaped first magnetic core In the inductor comprising a combination of two magnetic cores, the coil is formed by winding a rectangular conductor having a square cross section as a first layer in a spiral shape, and a rectangular conductor having an inner peripheral side is wound on the first layer of winding. It is wound in a spiral shape so as to form a second layer that overlaps from the circumferential side to the outer circumferential side, and the combined body is in a direction opposite to the generated magnetic field of the coil on at least one of the inner circumferential side or the outer circumferential side of the coil The inductor is characterized in that the coil and the combined body are sandwiched between the first and second magnetic cores so as to apply a magnetic bias to the inductor.   The inductor according to claim 1, wherein the combined body is a bonded magnet.   2. The inductor according to claim 1, wherein the combined body is formed by solidifying a resin paste containing rare earth magnet powder.   The end of the flat conducting wire at the start of winding of the coil and the end of the flat conducting wire at the end of winding are bent, and the tip of the bent portion is formed as an external mounting terminal. The inductor according to claim 3.   The end of the rectangular conductor at the beginning of winding of the coil and the end of the rectangular conductor at the end of winding are bent along the outer surface of the magnetic core, and the tip is disposed on the bottom of the magnetic core. The inductor according to any one of claims 1 to 3.   The inductor according to claim 4 or 5, wherein the tip portion is crushed by a press.   The inductor according to any one of claims 1 to 6, wherein the coil is molded with an insulating resin and is incorporated between the first magnetic core and the second magnetic core together with the combined body. .   A flat first magnetic core, a coil, a 2-17-type Sm-Co-based, Nd-Fe-B-based, or Sm-Fe-N-based rare earth magnet powder bonded body, and a plate-shaped first magnetic core In the inductor formed by combining two magnetic cores, the coil is formed by connecting a plurality of unit coils, and the unit coil is wound as a first layer in a spiral shape with a rectangular wire having a square cross section, The flat rectangular wire thus formed is overlapped on the first layer winding from the inner circumference side to the outer circumference side and wound in a spiral shape so as to be the second layer, and at least one of the inner circumference side or the outer circumference side of the coil The coupling body is installed to apply a magnetic bias in a direction opposite to a magnetic field generated by the coil, and the coil and the coupling body are sandwiched between the first and second magnetic cores. Characteristic inductor   A flat first magnetic core, a coil, a 2-17-type Sm-Co-based, Nd-Fe-B-based, or Sm-Fe-N-based rare earth magnet powder bonded body, and a plate-shaped first magnetic core In the manufacturing method of an inductor comprising a combination of two magnetic cores, a rectangular conductor having a rectangular cross section is spirally wound around a winding core to form a first layer winding, and a single layer of a rectangular conductor on the inner periphery side. On the winding of the eye from the inner peripheral side to the outer peripheral side, and spirally winding the second layer to produce the coil, and at least one of the inner peripheral side or the outer peripheral side of the coil After applying the resin paste of the rare earth magnet powder, the step of combining so as to be sandwiched between the first and second magnetic cores, and after applying so that a magnetic bias is applied in the direction opposite to the magnetic field generated by the coil Of the rare earth magnet powder Inductor manufacturing method which comprises a step of orienting the.   10. The method for manufacturing an inductor according to claim 9, wherein the step of orienting the rare earth magnet powder is a step of applying a pulse current in a direction opposite to a coil energizing direction during use to magnetically align the rare earth magnet powder.

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