JP2006324457A - Coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil component in which reliability is enhanced by relaxing stress applied to a core in the vicinity of projecting position of a terminal and suppressing occurrence of cracking or chipping of the core caused by vibration of an engine. <P>SOLUTION: The coil component comprises a core 20 produced by pressure molding pulverized magnetic material covered with an insulating coating and mixed with a binder, a coil 22 formed by winding a wire spirally and buried in the core 20 while projecting the end therefrom, a member 23 for holding the end of the coil 22, and a terminal 24 arranged on the side face of the core 20. The terminal 24 is formed by bending the end of the coil 22 from the side face of the core 20 toward the lower surface thereof while superposing on the holding member 23, and a recess 25 is provided in the side face of the core 20 from a projecting position at the end of the coil 22 toward the upper surface of the core 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 coil component.

  In FIG. 5, in the control system for controlling the fuel injection device of the automobile engine, the control control unit 2 to which the driving current is supplied 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 5 includes a filter unit 8 including a coil component 6 and a capacitor component 7, and a DC / DC converter circuit including a coil component 6, a capacitor component 7, an IC 9, and a switching component 10. 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 shown in FIGS. 7 and 8, the coil component 6 is formed by winding a magnetic material into powder, covering the surface with an insulating coating, mixing a binder, and press-molding the magnetic core 14 and a conductive wire in a spiral shape. And a coil 16 embedded in the magnetic core 14 and a terminal 18 electrically connected to the end of the coil 16. The end of the coil 16 is electrically connected to a terminal 18 in a state of being embedded in the magnetic core 14, and the terminal 18 protrudes from the side surface of the magnetic core and is bent from the side surface of the magnetic core toward the lower surface.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2002-203731 A

  Since the coil component is used in the DC / DC converter circuit unit 11 in the vicinity of the automobile engine, it is easily subjected to engine heat and vibration, and heat resistance and impact resistance are required. In particular, the coil component 6 projects the terminal 18 electrically connected to the coil 16 from the side surface of the magnetic core 14 and bends the side surface from the side surface of the magnetic core 14 to the lower surface. The magnetic core 14 is under stress, and the magnetic core 14 may be cracked or chipped due to engine vibration. In this case, the magnetic core pieces and magnetic core powder accompanying the cracks and chips are scattered in the DC / DC converter circuit unit 11 and adhered between the wiring patterns connecting the electronic components mounted on the DC / DC converter circuit unit 11 to each other. There is a problem that a short circuit occurs between electronic components, which may reduce reliability.

  The present invention solves the above-described problems, and relaxes the stress on the magnetic core in the vicinity of the protruding position of the terminal, suppresses the occurrence of cracking and chipping of the magnetic core due to engine vibration, and improves the reliability. The purpose is to provide.

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

  The present invention provides a magnetic core made of a magnetic material, covered with an insulating film, mixed with a binder, and press-molded, a coil embedded in the magnetic core and having an end protruding from the magnetic core, A holding member for holding the end portion, the end portion of the coil being overlapped with the holding member and being bent from the side surface of the magnetic core toward the lower surface, and the end of the coil is provided on the side surface of the magnetic core. In this configuration, a concave portion is provided from the protruding position of the portion toward the upper surface of the magnetic core.

  With the above configuration, since the recess is provided from the protruding position where the end of the coil protrudes toward the upper surface of the magnetic core, even if the end of the coil is bent from the side surface of the magnetic core toward the lower surface, The stress related to the vicinity of the protruding position of the end is relieved. In particular, since the end portion of the coil is bent from the side surface of the magnetic core toward the lower surface, the upper end side of the coil expands and the lower surface side contracts to relieve stress on the upper surface side of the magnetic core, Generation of cracks and chipping in the magnetic core can be suppressed.

  Further, since the end of the coil is overlapped with the holding member and is bent, the end of the coil can be accurately positioned by the holding member even if the coil is formed by winding a conductive wire in a spiral shape. .

  In the following, embodiments of the present invention will be described with reference to the drawings.

  1 is a perspective view of a coil component according to an embodiment of the present invention, FIG. 2 is a sectional view of the coil component mounted, FIG. 3 is a perspective view of a coil of the coil component, and FIG. It is process drawing which shows a part of process.

  1 to 3, the coil component of the present invention is formed by magnetically powdering a magnetic material, covering the surface with an insulating film, mixing a binder, and press-molding the magnetic core 20, and winding a conductive wire in a spiral shape. The coil 22 is embedded in the magnetic core 20 and has an end protruding from the magnetic core 20, a holding member 23 that holds the end of the coil 22, and a terminal 24 disposed on the side surface of the magnetic core 20.

  The terminal 24 is formed by overlapping the end portion of the coil 22 on the holding member 23 and bending the side surface of the magnetic core 20 from the bottom surface. The holding member 23 is made of metal, and the holding member 23 and the end of the coil 22 are electrically connected to form a terminal 24 in which these are integrated.

  Further, a concave portion 25 is provided on the side surface of the magnetic core 20 from the protruding position of the end portion of the coil 22 toward the upper surface of the magnetic core 20, and the end portion of the holding member 23 is also embedded in the concave portion 25.

  Then, the solder 30 is applied to the terminals 24 and the coil components are mounted on the mounting substrate 32.

  The manufacturing method of the said coil components is as follows.

  FIG. 4A is a process diagram showing a state where re-press molding is performed with a mold so that a coil is sandwiched between two green compacts, and FIG. 4B is a state where re-press molding is completed with the same mold. It is process drawing shown.

  As shown in FIGS. 4 (a) and 4 (b), the magnetic core 20 is in a non-heated state in which the thermosetting resin does not completely cure the binder containing the thermosetting resin and the magnetic powder powdered from the magnetic material. The two green compacts 34 mixed and pressure-molded in step 2 are re-press-molded with a mold 36 so that the coil 22 is sandwiched, and the coil 22 is covered with the green compact 34 and the thermosetting resin is completely formed. It is molded by heating to cure.

At this time, the pressing force at the time of re-pressing molding is larger than the pressing force at the time of pressure molding, and the pressing force at the time of pressing molding the green compact 34 is about 0.5 to ¹ ton / cm ^2. Thus, the pressure applied at the time of re-pressure molding for molding the magnetic core 20 from the green compact 34 is about 3 to 5 ton / cm ² .

  With the above configuration, since the recess 25 is provided from the protruding position where the end of the coil 22 protrudes to the upper surface of the magnetic core 20, the end of the coil 22 is bent from the side surface of the magnetic core 20 toward the lower surface. The stress related to the vicinity of the protruding position of the end of the coil 22 is relaxed. In particular, since the end portion of the coil 22 is bent from the side surface of the magnetic core 20 toward the lower surface, the end portion of the coil 22 expands on the upper surface side of the magnetic core 20 and contracts on the lower surface side, thereby causing stress on the upper surface side of the magnetic core 20. Can be reduced, and the occurrence of cracks and chipping of the magnetic core 20 can be suppressed.

  In particular, since the end portion of the coil 22 is overlapped with the holding member 23 and is bent, even if the coil 22 is formed by winding a conductive wire in a spiral shape, the end of the coil 22 is accurately detected by the holding member 23. The part can be positioned. At this time, the holding member 23 is made of metal, and the end portion of the coil 22 and the holding member 23 are electrically connected to form a terminal 24 in which these are integrated, and the connection reliability is good.

  The magnetic core 20 includes a plurality of green compacts obtained by mixing a binder containing a thermosetting resin and a magnetic powder obtained by powdering a magnetic material in a non-heated state in which the thermosetting resin is not completely cured, and press-molding. 34 is re-press-molded so as to sandwich the coil 22, the coil 22 is covered with the green compact 34, and the thermosetting resin is heated and molded so as to be completely cured. Between the coil 22 and the coil 22 without gaps, the magnetic gap can be reduced and the magnetic efficiency can be improved. In particular, since the pressing force at the time of re-pressing molding is larger than the pressing force at the time of pressure molding, not only the gap between the green compact 34 and the coil 22 but also the green compact 34 itself is formed. It is possible to densely form the entire magnetic core 20 in which the coil 22 is embedded, and the gaps that are embedded are densely filled.

  As described above, the coil component according to the present invention relieves stress related to the magnetic core in the vicinity of the protruding position of the terminal, and thus can be applied to various electronic devices and communication devices.

The perspective view of the coil components in one embodiment of this invention Cross-sectional view of the coil component mounted state Coil perspective view of the coil component Process diagram showing a part of the manufacturing process 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 Perspective view of the coil component

Explanation of symbols

20 Magnetic core 22 Coil 23 Holding member 24 Terminal 25 Recessed part 30 Solder 32 Mounting substrate 34 Green compact 36 Mold

Claims (5)

A magnetic core made of powdered magnetic material, covered with an insulating film, mixed with a binder, and press-molded, a coil embedded in the magnetic core and having an end protruding from the core, and the end of the coil held A holding member that overlaps the holding member and is bent from the side surface of the magnetic core toward the lower surface, and the protruding position of the end portion of the coil is formed on the side surface of the magnetic core. The coil component which provided the recessed part toward the upper surface of the said magnetic core from. The coil component according to claim 1, wherein an end of the holding member is embedded in a recess provided on a side surface of the magnetic core. The coil component according to claim 1, wherein the holding member is a metal and is electrically connected to an end of the coil. The magnetic core comprises a plurality of green compacts obtained by pressing and molding a binder containing a thermosetting resin and a magnetic powder obtained by powdering a magnetic material in a non-heated state where the thermosetting resin is not completely cured. The coil component according to claim 1, wherein the coil component is re-press-molded so as to sandwich the coil, and the coil is covered with the green compact and is heated and molded so that the thermosetting resin is completely cured. The coil component according to claim 4, wherein the pressurizing force at the time of repressurizing is larger than the pressurizing force at the time of press forming.

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