JP2009076610A - Magnetic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic component such that the formation of a large gap between an undersurface of a core opposed to a mounting substrate and an external terminal can be easily suppressed. <P>SOLUTION: One or more pairs of external terminals which have parts wound with a conductor and are made of metal plates are disposed at a pair of ends of a core, and portions of the external terminals are disposed on respective undersurfaces of the cores opposed to the mounting substrate, parts of the undersurfaces of the core where the external terminals are disposed being more apart from a line connecting border portions between the pair of ends and the undersurfaces as the parts go from the pair of ends of the core to the center portion of the core disposed between the pair of ends in a surface-mounted state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic component.

  Patent Document 1 discloses a magnetic component for surface mounting (for example, a common mode choke coil) in which external terminals made of a metal plate are arranged along a part or all of the shape of an end portion of a core. In such a magnetic component, a metal plate formed in a U-shape when viewed from the side is usually covered with an end portion of the core to serve as an external terminal.

JP 2003-234218 A

  When the above-mentioned external terminal covers the end of the core with a U-shaped metal plate, the U-shape may be deformed and spread. Then, a large gap is generated between the lower surface of the core facing the mounting substrate and the external terminal. Due to the presence of the gap, the mounting state of the magnetic component on the mounting board is not good. In particular, in a four-terminal common mode choke coil having four external terminals, there may be a difference in the size of each gap. In this case, the distance between the mounting board and the external terminal is increased, and electrical connection to the mounting board may not be performed. In order to prevent the generation of such a gap, at present, it is pushed and bent so as to return the spread, but even with such a push, the generation of the gap cannot be completely eliminated.

  Moreover, when using the technique of the above-mentioned patent document 1, there exists a possibility that an external terminal may not expand a U-shape. However, using the technique of Patent Document 1, that is, both ends of the external terminal are bent at an acute angle so that the width of each of the external terminals becomes narrower toward the tip. For this reason, it is difficult for the core to enter the opening having a narrow width between both ends, and it is very difficult to mount the core in such a manner that the core is first mounted from the opening. Therefore, the external terminal is attached from the side of the core. Specifically, of the U-shaped external terminals, the vicinity of the side part to which both ends are connected first enters the core, and then both ends are brought into contact with the upper and lower surfaces of the core while shifting the external terminals. At the same time, it is mounted at a predetermined mounting position. However, such a mounting method is time-consuming. In addition, according to the technical content disclosed in Patent Document 1, unless dimensional tolerances at both ends bent at an acute angle are strictly controlled, the magnetic parts are not easily assembled. However, such management takes time and cost. It has become. In addition, it is more difficult to place and mount such external terminals on the core.

  Therefore, an object of the present invention is to provide a magnetic component that can easily suppress the generation of a large gap between the lower surface of the core facing the mounting substrate and the external terminal.

  In order to solve the above problems, a magnetic component of the present invention has a portion around which a conducting wire is wound, and at least a pair of external terminals made of a metal plate are arranged at a pair of end portions of the core, respectively, A portion of the external terminals are disposed on the lower surface of each of the cores facing each other, and the portion of the lower surface of the core where the external terminals are disposed is surface-mounted from the pair of end portions of the core. It has the shape which goes away from the line | wire which connects the boundary part between a pair of edge part and a lower surface as it goes to the center part of the core located between parts.

  In the magnetic component of the present invention, the portion of the lower surface of the core where the external terminals are arranged is from the pair of end portions of the core to the center portion of the core located between the pair of end portions in a surface-mounted state. Since it has a shape that moves away from the line connecting the boundary portions between the pair of end portions and the lower surface as it goes, the external terminal may be bent at an acute angle from the end portion of the core to the center portion of the core. It becomes possible. Therefore, even if the U-shape of the external terminal is once deformed and widened and a large gap is generated between the lower surface of the core and the external terminal, the external terminal is extended from the end of the core to the center of the core. By bending at an acute angle, the external terminal can be shaped to easily reduce the gap. In addition, the boundary between the pair of end portions and the bottom surface as the bottom surface of the core is surface-mounted from the pair of end portions of the core toward the center portion of the core located between the pair of end portions. When the shape is parallel to the line connecting the parts, the external terminals are not sufficiently bent and shaped. The reason is that there is a slight return after bending due to the spring property of the metal plate. Moreover, since the external terminal can be a conventional U-shape, it is easy to suppress the generation of a large gap between the lower surface of the core and the external terminal.

  In addition to the above-described invention, another magnetic component according to the present invention is provided with four external terminals at the end of the core. By adopting this configuration, even if a large gap is generated between the lower surface of the core of a magnetic component such as a 4-terminal common mode choke coil and the external terminal, the gap can be easily reduced thereafter.

  According to another magnetic component of the present invention, in addition to the above-described invention, the external terminal has an upper portion disposed on the upper surface of the core opposite to the surface facing the mounting substrate. Is formed by bending, and a folded portion that sandwiches the conducting wire together with the upper portion is continuously provided on the upper surface of the core. By adopting this configuration, the electrical connection between the external terminal and the conductive wire can be easily realized.

  As described above, according to the present invention, it is possible to provide a magnetic component that can easily suppress generation of a large gap between the lower surface of the core facing the mounting substrate and the external terminal.

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

(Configuration of magnetic parts)
The magnetic component 1 includes, for example, a core 2 made of a magnetic material such as Mn—Zn ferrite or Ni—Zn ferrite, an external terminal 3 made of a steel plate coated with solder, and a copper wire surface. The lead wire 4 covered with enamel is the main component.

  FIG. 1 is an exploded perspective view showing a core 2 and external terminals 3 constituting a magnetic component 1 according to an embodiment of the present invention. Note that the two external terminals 3 on the right side in the figure are moved in the direction of the arrow in the figure, and the end of the core 2 is sandwiched. FIG. 2 shows a cross-sectional view taken along the line A-A ′ in FIG. 1 of the core 2 and the external terminal 3 in such a sandwiched state.

  As shown in FIG. 2, the magnetic component 1 is a surface-mounting magnetic component 1 in which external terminals 3 made of a metal plate are arranged along the shape of the end portions (upper surface 2A, end surface 2B, lower surface 2C) of the core 2. It is. The bottom 3C of the external terminal 3 is disposed on the lower surface 2C of the core 2 facing the mounting substrate (not shown). And the part (lower surface 2C) in which the external terminal 3 is arrange | positioned among the cores 2 approaches gradually to the upper surface 2A as it goes from the edge part (end surface 2B) of the core 2 to the center part of the core 2. It has a planar shape with an inclination. The inclination angle is 2 ° with respect to the upper surface 2A.

  As shown in FIG. 1, the core 2 connects a pair of end portions (a portion having an upper surface 2 </ b> A, an end surface 2 </ b> B, and a lower surface 2 </ b> C) where the external terminals 3 are arranged, and the conductive wire 4 is wound around the core 2. Two columnar portions 2D having a substantially quadrangular prism shape are provided. The columnar portion 2D is disposed above the pair of end portions, and a gap is formed between the lower surface of the columnar portion 2D and the mounting substrate when mounted on the mounting substrate. A gap is also formed between the two columnar portions 2D. As a result, a square ring-shaped space is formed by the pair of end portions and the two columnar portions 2D. Moreover, the end surface 2B has a groove 2B1 (concave portion) into which the external terminal 4 is fitted. Note that the columnar portion 2 </ b> D in this embodiment is a central portion of the core 2.

  As shown in FIG. 2, the external terminal 3 has a folded portion 3 </ b> D continuous from the upper portion 3 </ b> A. The folded portion 3D and the upper portion 3A are folded so as to form a substantially U shape. The tip side of the folded portion 3D is positioned closer to the side portion 3B than the tip of the upper portion 3A (ie, the boundary with the folded portion 3D). In addition, the boundary between the upper part 3A and the side part 3B and the boundary between the side part 3B and the bottom part 3C are bent at 90 °, respectively, so that a U-shape is formed between the upper part 3A, the side part 3B and the bottom part 3C of the external terminal 3. It is in the shape of Therefore, as shown in FIG. 1, a gap is formed between the slope formed on the lower surface 2C of the core 2 and the bottom 3C. As shown in FIG. 1, a notch 3E that facilitates bending of the bent portion is formed in the vicinity of the bent portion of the side portion 3B and the upper portion 3A. 2 and the like show a configuration in which a gap is provided, but a configuration in which the bottom 3C is in close contact with the lower surface 2C and no gap exists may be used.

  As described above, the external terminal 3 moves in the direction of arrow B in FIG. 1, and both are fixed with the end of the core 2 being sandwiched. For this fixing, an epoxy adhesive (not shown) is disposed at the contact portion between the groove 2B1 of the end surface 2B of the core 2 and the side 3B of the external terminal 3.

  In FIG. 3, the conducting wire 4 is wound around the columnar portion 2D, and one end of the conducting wire 4 is attached and fixed between the folded portion 3D and the upper portion 3A. In this mounting and fixing, the conducting wire 4 is positioned between the folded portion 3D and the upper portion 3A that are bent in advance, and the conducting portion 4 is pressed by pressing the folded portion 3D, and the conducting wire 4 is sandwiched by the pressing force. Fixed and engaged. The state shown in FIG. 3 is the same for the other end of the conducting wire 4. In this fixing, the folded portion 3D and the conductive wire 4 are soldered and both are electrically connected to each other. Therefore, the magnetic component 1 is a four-terminal common mode choke coil having four external terminals 3.

(Method for manufacturing magnetic parts)
The magnetic component 1 configured as described above is manufactured as follows.

  First, the core 2 shown in FIG. 1 is prepared. Then, an epoxy adhesive is applied to the four groove portions 2B1 of the end surface 2B of the core 2. Before the applied adhesive is dried, the four external terminals 3 are fitted into the groove 2B1 at the end of the core 2, respectively. At the time of the fitting, the upper surface 2A and the upper portion 3A, the groove portion 2B1 and the side portion 3B of the end surface 2B, and the lower surface 2C and the bottom portion 3C face each other. Then, the core 2 and the external terminal 3 are fixed with an adhesive.

  Then, as shown in FIG. 4A, the space between the upper portion 3A and the bottom portion 3C of the external terminal 3 increases toward the front end side away from the base with respect to the side portion 3B. It is assumed that a large substantially triangular gap is formed between the bottom 3C and the lower surface 2C of the core 2. Therefore, as shown in FIG. 4 (B), the bottom 3C of the external terminal 3 is pressed upward (in the direction of the arrow in FIG. 4 (B)) so as to be along the lower surface 2C (slope) of the core 2. Here, the bottom portion 3C is bent with respect to the side portion 3B by the pressing force, and the external terminal 3 is plastically deformed at the boundary portion between the side portion 3B and the bottom portion 3C. Thereafter, when the pressing force is released, as shown in FIG. 4C, the bottom 3C returns slightly downward (in the direction opposite to the arrow direction in FIG. 4) due to its springiness. However, due to the plastic deformation described above, the bottom 3C does not return completely. FIG. 4C shows a state in which the bottom 3C is substantially parallel to the surface of the mounting board on which the magnetic component 1 is mounted. The pressing operation shown in FIG. 4 is performed for all four external terminals 3. Further, the pressing operation shown in FIG. 4 is performed even when the U-shape of the external terminal 3 is not widened. Further, the pressing in the direction of the arrow in FIG. 4B is performed until the bottom 3C is substantially parallel to the surface of the mounting board on which the magnetic component 1 is mounted as shown in FIG. 4C. Therefore, the number of times of pressing in the arrow direction in FIG. 4B may be one time or may be two times or more.

  Then, the conducting wire 4 is wound around the two columnar portions 2D of the core 2, respectively. One end and the other end of the conducting wire 4 are engaged with the folded portion 3D of the external terminal 3 as shown in FIG. In the engaged state, the top of the folded portion 3D is pressed downward (bent and crimped). After the pressing, the contact portion between the folded portion 3D and the conductive wire 4 is connected with solder, thereby securing the both more securely. Thus, the magnetic component 1 of the four-terminal common mode choke coil according to this embodiment is completed.

(Main effects of this form)
As described above, in this embodiment, the lower surface 2C of the core 2 has a shape that moves away from the line connecting the boundary portions between the pair of end portions and the lower surface 2C as it goes from the end portion of the core 2 to the center portion. is doing. Therefore, even if a large gap occurs between the lower surface 2C of the core 2 and the bottom 3C of the external terminal 3 once the U-shape of the external terminal 3 is deformed and widened, the gap is easily reduced thereafter. The bottom 3C of the external terminal 3 can be bent and shaped so that the bottom 3C of the external terminal 3 is parallel to the surface of the mounting substrate. As a result, the state in which the bottom 3C and the surface of the mounting substrate are solder-bonded can be improved.

  In view of the strength of the solder joint and the like, the inclination angle of the lower surface 2C with respect to the upper surface 2A is preferably such that the bottom 3C of the external terminal 3 and the upper surface 2A (the surface of the mounting substrate) are substantially parallel. However, as a result of pressing against the bottom portion 3C, for example, even if an acute angle is formed between the bottom portion 3C and the side portion 3B so that the bottom portion 3C is along the lower surface 2C, the magnetic component 1 is lifted up. The floating of the terminal 3 can be eliminated.

  In the present embodiment, the external terminals 3 are provided at four locations on the core 2. In the four-terminal magnetic component 1 such as a four-terminal common mode choke coil, if there is a large gap between the bottom 3C and the lower surface 2C of the core 2 among the external terminals 3, the other small external terminals are mounted. There is an inconvenience that it is lifted from the surface of the substrate to increase the distance from the surface of the mounting substrate, and electrical connection to the mounting substrate becomes difficult. However, in the present embodiment, as described above, the bottom 3C can be bent and shaped to make the gaps uniform in size, so that such inconvenience can be suppressed.

  In this embodiment, one end and the other end of the conducting wire 4 are fixed and engaged with the upper surface 2A of the core 2 by bending of the folded portion 3D, and the folded portion 3D is a part of the external terminal 3. The fixing between the external terminal 3 and the conductive wire 4 can be strengthened and the number of parts is not increased. In addition to this fixing, the folded portion 3D and the conductive wire 4 are soldered, and the fixing can be more reliably performed.

  Further, in this embodiment, even if the dimensional tolerance between the core 2 and the external terminal 3 is increased, the dimensional variation of the magnetic component 1 can be reduced and the defect occurrence rate can be reduced. The reason is that in this embodiment, even if the U-shape of the external terminal 3 spreads, it can be corrected. Conventionally, since such a correction has not been made, it is necessary to reduce the dimensional tolerance between the core 2 and the external terminal 3 in order to reduce the dimensional variation of the magnetic component 1.

(Other embodiments)
The magnetic component 1 according to the present embodiment described above is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made as follows without departing from the scope of the present invention. Is possible.

  In the embodiment described above, the magnetic component 1 is a four-terminal common mode choke coil, but is not limited thereto, and may be a magnetic component such as a two-terminal inductor.

  In the embodiment described above, the inclination angle of the lower surface 2C of the core 2 is set to 2 ° with respect to the surface of the mounting substrate. However, the angle can be appropriately changed according to the material, thickness, etc. of the external terminal 3. Preferably, this angle is 1 to 10 °. By setting this angle to 1 ° or more, as shown in FIG. 4, when the pressing force is released after pressing the bottom 3C of the external terminal 3 upward, the bottom 3C can be easily and surely formed into a desired shape. It can be deformed. Further, by setting the angle to 10 ° or less, it is possible to suppress the bottom portion 3C from being excessively deformed by the above-described pressing, and difficult to attach the solder during mounting.

  In the above-described embodiment, the shape of the lower surface 2C of the core 2 is a flat surface having an inclination. However, the shape is not limited to this shape, and the lower surface 2C of the core 2 is centered from the end of the core 2. As it goes to the portion, it can be formed in a shape that is stepped away from a line connecting the boundary portions between the pair of end portions and the lower surface 2C, or a curved surface shape that is away from the line. However, considering the ease of molding of the core 2, it is preferable to have a flat shape having a simple slope as shown in FIG.

  Further, in the embodiment described above, the external terminal 3 has an upper part 3A, a side part 3B, a bottom part 3C, and a folded part 3D. However, the upper portion 3A and the folded portion 3D are not essential components and can be omitted. For example, instead of the external terminal 3 molded into a U-shape, an external terminal molded into an L-shape including only the side portion 3B and the bottom portion 3C can be used.

  In the embodiment described above, the external terminal 3 before being fitted into the core 2 is bent at 90 ° at the boundary between the upper part 3A and the side part 3B and at the boundary between the side part 3B and the bottom part 3C. However, these boundaries can be bent at, for example, 91 ° to 120 °. Bending at 91 ° or more has the same effect as fitting into the end of the core 2 in a state where the external terminal 3 is tapered, and the work of fitting the external terminal 3 into the core 2 is easy. Become. Moreover, by bending at 120 ° or less, for example, as shown in FIG. 4B, an excessive burden of the operation of pressing the bottom 3C of the external terminal 3 upward can be reduced.

  In the embodiment described above, the operation of pressing the bottom 3C of the external terminal 3 upward as shown in FIG. 4 and the folded portion 3D of the external terminal 3 as shown in FIG. The operation of bending the folded portion by pressing the topmost portion of the folded portion 3D downward is performed at different times. However, these two operations can be performed simultaneously. Pressing the bottom portion 3C upward and pressing the topmost portion of the folded portion 3D downward can be realized simultaneously by sandwiching the bottom portion 3C and the topmost portion of the folded portion 3D.

  In the embodiment described above, the pressing operation shown in FIG. 4 is performed on all four external terminals 3 and is performed even if the U-shape of the external terminals 3 is not widened. However, this pressing operation may be performed only on the external terminal 3 whose U-shape is widened.

  In the embodiment described above, there is no step of displaying information on the magnetic component 1 on the magnetic component 1 in particular. However, an insulating plate is fixed using a portion other than the folded portion at the end of the core 2 on the upper surface when the magnetic component 1 is mounted, a gap between the two columnar portions 2D, and the like. Information on the magnetic component 1 is preferably displayed on the surface. The information on the magnetic component 1 is, for example, the orientation of the magnetic component 1 (information on which position each external terminal 3 is), the inductance value of the magnetic component 1, and the like. Such information may be displayed after being encrypted in accordance with a standard or the like.

It is a perspective view which shows the core and external terminal which comprise the magnetic component which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view of the core and external terminals taken along the line A-A ′ in FIG. 1 in a state in which the two external terminals on the right side of FIG. It is a perspective view which shows the state by which conducting wire was wound around the columnar part of the core, and the end of the conducting wire was pinched | interposed and engaged by the bending pressing force of the folding | returning part of an external terminal. (A) is a state in which the U-shape of the external terminal has spread, (B) is a state in which the bottom portion shown in (A) is pressed upward (in the direction of the arrow) and along the bottom surface of the core, ( (C) is a figure which shows the state which released the press to the bottom part shown to (B), and the bottom part returned to the downward direction a little.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic component 2 Core 2A Upper surface (a part of edge part of core)
2B end face (part of the end of the core)
2C bottom surface (part of core end, core bottom surface)
2D columnar part (core part of the core)
3 External terminal 3C Bottom (part of external terminal)
3D folded part (bent part of external terminal)
4 conductors

Claims (3)

In a magnetic component for surface mounting in which at least a pair of external terminals made of a metal plate are disposed at a pair of end portions of the core, respectively, having a portion around which a conducting wire is wound,
A part of the external terminal is disposed on the lower surface of each of the cores facing the mounting substrate,
Of the lower surface of the core, the portion where the external terminal is arranged is surface-mounted from a pair of end portions of the core toward the center portion of the core located between the pair of end portions, A magnetic component having a shape that is away from a line that connects the boundary portions between the pair of end portions and the lower surface.   The magnetic component according to claim 1, wherein the external terminals are provided at four locations at the end of the core.   The external terminal has an upper portion disposed on the upper surface of the core opposite to the surface facing the mounting substrate, and the upper portion is formed by bending, and on the upper surface of the core The magnetic part according to claim 1, wherein a folded portion that sandwiches the conducting wire together with the upper portion is provided continuously.

Images