JP2005310869A - Coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil component whose reliability is improved without integrating a drum core and a ring core with adhesive so that heat resistance of adhesive is not necessary to be considered and suppressing disconnection of lead-out wires of coils. <P>SOLUTION: A coil component is provided with a core 30 whose cross section is rectangular, coils 32 which are formed by spirally winding conductors and are embedded in the core 30, and terminals 34 which are electrically connected to the coils 32. The terminals 34 are projected from upper face sides of sides of the core 30. Recesses 45 are installed at the sides of the core 30, which are confronted with the terminals 34. The terminals 34 are projected from edges 48 between top face of the recesses 45 and inner wall faces of the recesses 45. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coil component used in various electronic devices, communication devices, and the like.

  Hereinafter, a conventional technique will be described with reference to the drawings.

  FIG. 5 is a block diagram showing the entire control system for controlling the fuel injection device of the automobile engine, FIG. 6 is a circuit diagram of a power supply unit in the control control unit of the control system, FIG. 7 is a sectional view of the coil components, and FIG. It is a perspective view of the conventional coil components used for the power supply part.

  In FIG. 5, in the control system for controlling the fuel injection device of the automobile engine, the control control unit 2 supplied with the driving current from the battery 1 controls the fuel injection device 3 of the engine. The control control unit 2 is provided with a CPU 4 that calculates and controls the injection amount and injection timing of the fuel injection device, and a power supply unit 5 that supplies current to the CPU 4.

  As shown in FIG. 6, the power supply unit includes a filter unit 8 including a coil component 6 and a capacitor component 7, and a DC / DC converter circuit unit including a coil component 6, a capacitor component 7, an IC 9, and a switching component 10. 11 are connected to each other, the filter unit 8 is connected to the battery terminal 12 on the battery 1 side, and the DC / DC converter circuit unit 11 is connected to the CPU terminal 13 on the CPU 4 side. In particular, the coil component 6 used for the DC / DC converter circuit unit 11 is driven to be switched by the switching component 10, and the DC / DC converter circuit unit 11 sets the 12 V voltage of the battery 1 to about 1.5 to 5 V for the CPU 4. I have a pressure drop.

  As one of the coil components used in such a DC / DC converter circuit unit 11, as shown in FIGS. 7 and 8, a drum-shaped drum magnetic core 21 having hooks at both ends of the winding shaft unit 20, and the drum A coil 22 wound around the winding shaft portion 20 of the magnetic core 21, a ring-shaped ring magnetic core 23 combined with the drum magnetic core 21 so as to cover the coil 22, and a terminal portion 24 electrically connected to the coil 22. There is something with. The coil 22 is formed by spirally winding a conducting wire made of a round wire, and the lead wire 25 is wound around one end 26 of the L-shaped terminal portion 24.

  The drum magnetic core 21 and the ring magnetic core 23 are made of a ferrite material, and the drum magnetic core 21 and the ring magnetic core 23 are integrated by applying an adhesive 27.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2002-64024 A

  Since the conventional coil component is used for the DC / DC converter circuit unit 11 in the vicinity of the automobile engine, heat resistance is required. However, in the coil component, since the drum magnetic core 21 and the ring magnetic core 23 are integrated by applying the adhesive 27, the adhesive 27 melts depending on the heat-resistant temperature of the adhesive 27 and the reliability deteriorates. It had the problem that.

  In order to solve the above-described problems, an object of the present invention is to provide a coil component with improved heat resistance so that it is not necessary to consider the heat resistance of an adhesive.

  In order to solve the above problems, the present invention has the following configuration.

  The present invention comprises a magnetic material made of powdered powder, the surface is covered with an insulating film, a binder is mixed and pressure-molded, and a coil is formed by winding a conductive wire in a spiral, embedded in the magnetic core, A terminal portion electrically connected to the coil, and the terminal portion protrudes from a side surface of the magnetic core, is bent along the bottom surface from the side surface of the magnetic core, and faces the terminal portion. A concave portion is provided on the side surface of the magnetic core, and the terminal portion is projected from a ridge portion between the top surface of the concave portion and the side surface of the magnetic core.

  With the above configuration, the coil is embedded in a magnetic core that is made of a magnetic material powder, covered with an insulating film, mixed with a binder, and press-molded. Can be improved.

  In particular, the terminal portion protrudes from the side surface of the magnetic core and is bent along the bottom surface from the side surface of the magnetic core, and a concave portion is provided on the side surface of the magnetic core facing the terminal portion, and the top surface and the side surface of the magnetic core Since the terminal portion protrudes from the ridge portion, cracks and the like are hardly generated near the ridge portion of the terminal portion, and the reliability can be improved.

  That is, even if the magnetic core is pressure-molded with a mold from above and below so that the terminal portion protrudes from the side surface of the magnetic core, at least the mold from the downward direction presses the terminal portion toward the top surface of the recess. The stress applied to the terminal portion due to the pressurization of the mold is released to the ridge portion and the top surface of the magnetic core from which the terminal portion protrudes and is reduced.

  Hereinafter, the invention described in all claims of the present invention will be described using embodiments of the present invention.

  FIG. 1 is a cross-sectional view of a coil component when mounted on a mounting board according to an embodiment of the present invention, FIG. 2 is a bottom perspective view before bending a terminal portion of the coil component, and FIG. 3 is a perspective view of the coil component. FIG. 4 is an enlarged sectional view of a terminal portion of the coil component.

  1 to 4, a coil component according to an embodiment of the present invention includes a magnetic core 30 having a rectangular cross-section in which a magnetic material is powdered, the surface is covered with an insulating film, and a binder is mixed and pressure-molded. The coil portion 32 is formed by spirally winding a conductive wire and embedded in the magnetic core 30, and a terminal portion 34 electrically connected to the coil portion 32.

The magnetic core 30 is formed by mixing a binder containing a thermosetting resin and magnetic powder in a non-heated state in which the thermosetting resin is not completely cured, and press-molding at about 0.5 to 1 ton / cm ² . The green compact is re-press-molded so as to sandwich the coil part 32, and the coil part 32 is covered with the green compact and heated so that the thermosetting resin is completely cured. At this time, the re-press molding is performed at a pressure of about 3 to 5 ton / cm ² , which is larger than that of the press molding, and the thickness of the green compact is greater after the re-press molding than before the re-press molding. It is made thinner and the molding density is increased. In particular, the number of green compacts is two, one green compact has a prismatic shape with a housing portion that completely houses the coil portion 32, and the other green compact has a lid shape that covers one green compact. The lead wire 42 of the coil portion 32 protrudes from the interface of the two green compacts.

  The terminal portion 34 protrudes from the magnetic core 30 and is bent from the side surface to the bottom surface of the magnetic core 30. The terminal portion 34 overlaps the lead wire 42 and holds the position and shape of the lead wire 42. And a holding portion 44.

  A concave portion 45 is provided on the side surface of the magnetic core 30 facing the terminal portion 34, and the terminal portion 34 protrudes from a ridge portion 48 between the top surface of the concave portion 45 and the inner wall surface of the concave portion 45. The depth of the top surface of the recess 45 is substantially the same as the thickness of the terminal portion 34, and the recess 45 is provided with a tapered portion so that the depth increases toward the bottom surface side of the magnetic core 30. When the terminal portion 34 is bent, the side surface of the magnetic core 30 and the surface of the terminal portion 34 are made substantially the same, and at least a part of the terminal portion 34 is not in contact with the inner wall surface of the recess 45.

  The holding portion 44 is made of a metal flat plate having a self-supporting property that can hold the shape of the holding portion 44 independently. The self-supporting property here means that the shape of the holding portion 44 superimposed on the bent lead wire 42 is not easily deformed by an external force, and the position of the lead wire 42 with respect to the magnetic core 30 and the lead wire 42. It means having a rigidity that can hold the shape. The holding portion 44 has a rigidity that is at least greater than the rigidity of the lead wire 42.

  The holding portion 44 is provided with a groove portion 46 for housing the lead wire 42 of the coil portion 32 from the side surface to the bottom surface of the magnetic core 30 on the surface opposite to the magnetic core 30 side. In this groove portion 46, a through hole 50 is provided at a position facing the ridge portion 48 between the side surface and the bottom surface of the magnetic core 30, a lead wire 42 is disposed on the through hole 50, and the lead wire is placed on the through hole 50. 42 is bent from the side surface of the magnetic core 30 to the bottom surface.

  The width of the groove portion 46 is wider than the diameter of the lead wire 42, and the opening surface 52 of the groove portion 46 and the outer peripheral surface of the conducting wire are substantially flush with each other. The lead wire 42 is formed on the groove portion 46 by an adhesive. Glued and stored. This adhesion may be temporarily fixed, or may be connected to the land of the mounting substrate 37 by solder 39 during mounting.

  With the above configuration, the coil portion 32 is made of powdered magnetic material, covered with an insulating film, embedded in the magnetic core 30 formed by mixing and bonding a binder, so that the magnetic core 30 can be formed without using an adhesive. It can form and can improve heat resistance.

  In particular, the terminal portion 34 protrudes from the side surface of the magnetic core 30 and is bent along the bottom surface from the side surface of the magnetic core 30. The concave portion 45 is provided on the side surface of the magnetic core 30 facing the terminal portion 34. Since the terminal portion 34 protrudes from the ridge portion 48 between the top surface of 45 and the side surface of the magnetic core 30, cracks and the like hardly occur in the vicinity of the ridge portion 48 of the terminal portion 34, and the reliability can be improved.

  That is, even if the magnetic core 30 is pressure-molded with a mold from above and below so that the terminal portion 34 protrudes from the side surface of the magnetic core 30, at least the mold from the downward direction is the terminal portion toward the top surface of the recess 45. Since the pressure 34 is applied, the stress on the terminal portion 34 due to the pressurization of the mold is released to the ridge 48 and the top surface of the magnetic core 30 from which the terminal portion 34 protrudes, and is reduced.

  Since the concave portion 45 is provided with a tapered portion so that the depth of the top surface of the concave portion 45 increases toward the bottom surface side, the above effect can be easily obtained and the shape of the concave portion 45 ( Since the side surface side of the magnetic core 30 is formed in a trapezoidal shape so that the width becomes wider toward the bottom surface side of the magnetic core 30, it is easy to mold the mold.

  Further, since the terminal portion 34 is not in contact with the inner wall surface of the recess 45, even if stress is generated in the terminal portion 34 due to a difference in thermal expansion coefficient between the mounting substrate 37 and the magnetic core 30, the terminal portion is caused by the space in the recess 45. 34 can move to absorb the stress. That is, it can suppress that a crack and a chip | tip arise in the part of the side surface of the magnetic core 30 from which the terminal part 34 protrudes.

  The terminal portion 34 includes a lead wire 42 of the coil portion 32 that is bent from the magnetic core 30 and a holding portion 44 that overlaps the lead wire 42 and holds the position and shape of the lead wire 42. The position and shape of the lead wire 42 of the coil portion 32 bent by the holding portion 44 can be held, and the lead wire 42 itself can be used as the terminal portion 34. As a result, it is not necessary to tie the lead wire 42 to the terminal portion 34, the disconnection of the lead wire 42 can be suppressed and the reliability can be improved, and the thickness of the coil portion 32 can be increased in order to increase the number of turns of the coil portion 32. Even if the wire diameter of the coil portion 32 is reduced or the wire diameter of the coil portion 32 is reduced, the lead wire 42 itself becomes easily bent or becomes independent, thereby suppressing the disconnection of the lead wire 42 of the coil portion 32 and improving reliability. it can.

  Further, the magnetic core 30 includes a plurality of green compacts obtained by pressing and molding a plurality of green compacts obtained by mixing a binder containing a thermosetting resin and magnetic powder in a non-heated state where the thermosetting resin is not completely cured. Since the coil portion 32 is covered with the green compact and heated so that the thermosetting resin is completely cured, the coil portion 32 inside the magnetic core 30 is formed. Positioning can be performed accurately, and it is easy to control the molding density as intended, and the magnetic flux density distribution can be made uniform to prevent magnetic saturation.

  As described above, since the coil component according to the present invention can improve heat resistance and reliability, it can be applied to various electronic devices and communication devices.

Sectional drawing of the coil components at the time of mounting in one embodiment of this invention Bottom perspective view of the same coil component before bending the terminal Perspective view of the coil component Enlarged sectional view of the terminal part of the coil component The block diagram which shows the whole control system which controls the fuel injection device of the automobile engine Circuit diagram of the power supply unit in the control unit of the control system Cross-sectional view of the coil component A perspective view of a conventional coil component used for the power supply unit

Explanation of symbols

30 Magnetic core 32 Coil part 34 Terminal part 37 Mounting board 39 Solder 42 Lead wire 44 Holding part 45 Recess 46 Groove part 48 Ridge part 50 Through-hole 52 Opening surface

Claims (6)

Magnetic material is powdered, the surface is covered with an insulating film, a binder is mixed and pressure-molded, a magnetic core is formed by winding a conductive wire in a spiral, and the coil is embedded in the magnetic core, and the coil is electrically A terminal portion connected to the magnetic core, the terminal portion protruding from a side surface of the magnetic core, bent from the side surface of the magnetic core along the bottom surface, and recessed on the side surface of the magnetic core facing the terminal portion. A coil component in which the terminal portion is protruded from a ridge between the top surface of the recess and the inner wall surface of the recess. The coil component according to claim 1, wherein the concave portion is provided with a tapered portion so that a depth of a top surface of the concave portion increases toward a bottom surface side of the magnetic core. The coil component according to claim 1, wherein the concave portion is formed in a trapezoidal shape so as to increase in width toward a bottom surface side of the magnetic core. The coil component according to claim 1, wherein the terminal portion protrudes from the ridge portion and is not in contact with the inner wall surface of the concave portion. The coil according to claim 1, wherein the terminal portion includes a lead wire of the coil that is bent from the magnetic core and a holding portion that holds the position and shape of the lead wire so as to overlap the lead wire. parts. The magnetic core sandwiches the coil portion with a plurality of green compacts obtained by mixing and molding a binder containing a thermosetting resin and magnetic powder in a non-heated state where the thermosetting resin is not completely cured. The coil component according to claim 1, wherein the coil part is re-press-molded in such a manner that the coil part is covered with the green compact and is heated and molded so that the thermosetting resin is completely cured.

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