JP4307422B2 - Coil parts - Google Patents

Description

  The present invention relates to a coil component mounted on a surface of a circuit board.

  Conventionally, coil components such as choke coils and noise filters in an electric circuit include coil components including a drum core and a ring core manufactured by sintering ferrite or the like. This coil component includes a core part and flanges provided at both ends of the core part. A winding is wound around the core portion of the drum core, and an annular ring core is disposed around the drum core with an appropriate gap. By forming an appropriate gap between the drum core and the ring core, magnetic saturation caused by contact or proximity between the drum core and ring core having a high magnetic permeability is prevented.

  Since a winding is wound around the drum core, it is necessary to extend one end and the other end of the winding from between the ring core and the drum core to the outside. In general, since the gap between the drum core and the ring core is smaller than the diameter of the conducting wire used for the winding, it is necessary to widen the gap in the portion where the winding is extended.

Further, in order to extend the winding, in Patent Document 1, a notch is formed in the flange portion of the drum core and a notch is also formed in the ring core, and winding is performed from an opening configured by matching the notch position. One end and the other end of the
JP 2003-217842 A

  However, if the winding is extended with the gap widened, the gap width cannot be set to the specified value for the portion where the winding is extended. It did not help in formation. Further, when the gap is widened by cutting the inner periphery of the ring core without changing the outer diameter of the ring core, the strength of the ring core may be reduced and damaged. When the gap is formed while the outer diameter of the ring core is increased and the predetermined thickness is maintained, the strength of the ring core can be suppressed from decreasing, but the volume of the entire coil component is increased.

  Further, as shown in Patent Document 1, when a notch is formed in a part of the ring core, the strength of the ring core in which the notch is formed is reduced and becomes a weak point. In this case as well, the coil component as a whole is large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a coil component that is small as a whole.

To achieve the above object, the present invention provides a drum core having a columnar core part and a pair of flanges provided at both ends of the core part, and one end and the other end wound around the core part. A winding extending outside the drum core, a pair of arm portions provided outside the drum core, made of a composite material of a magnetic body and a resin, and extending in parallel, and a bottom portion provided on the base end side of the pair of arm portions And a U-shaped core having a substantially U shape . In the cross section perpendicular to the axial direction of the winding core portion of the coil component, the inner circumference facing the drum core of the U-shaped core is smoothly formed in an arc shape, and the outer circumference of the U-shaped core in the cross section is a pair of arm portions. A pair of planes extending in the same direction as the extending direction of the arm part, a plane extending in a direction intersecting the extending direction of the arm part and extending in the same direction as the extending direction of the arm part, It is composed of a pair of planes connecting each plane and the bottom plane, and one end and the other end of the winding are open ends of the U-shaped core with the U-shaped core attached to the drum core. It is characterized by extending from the side opening position.

  According to such a configuration, the extending position of the winding can be concentrated in one direction. Further, since the U-shaped core is smaller than the conventional ring core, the size of the entire coil component can be reduced. In addition, by configuring the U-shaped core with a composite material of a magnetic material and a resin, elasticity can be increased compared to a magnetic core configured by sintering ferrite or the like. Therefore, durability against impact or the like can be improved. In addition, in the case of a core constituted by sintering, there is a possibility that distortion may occur during sintering, but when the magnetic substance and the resin are solidified, there is little occurrence of distortion, and provisionally distortion occurs. Even if the U-shaped opening is narrowed, it can be attached to the drum core because of its elasticity.

  In the above coil component, the pair of flanges has a bottom facing portion facing the inner surface of the bottom located on the non-opening side of the U-shaped core in a state where the U-shaped core is mounted on the drum core, It is preferable that the outline and the outline of the bottom facing portion are substantially equal. Further, it is preferable that the bottom inner surface contour and the bottom facing portion contour are each formed in an arc shape, and the curvature radius of the bottom inner surface contour and the curvature radius of the bottom facing portion contour are substantially equal.

  According to such a configuration, the drum core and the U-shaped core can be brought into close contact with each other. When the drum core and the U-shaped core are in close contact with each other, the rigidity of the entire coil component can be increased and the strength can be increased. In general, a core made of a composite material of a magnetic body and a resin has a lower magnetic permeability than a core formed by sintering a magnetic body. However, since the drum core and the U-shaped core can be in close contact with each other, the magnetic flux can be concentrated. Further, the bottom inner contour and the bottom facing contour are each formed in an arc shape, thereby simplifying the configuration of the drum core and the U-shaped core and maintaining the adhesion between the drum core and the U-shaped core. .

  In the coil component, a pair of electrodes to which one end and the other end of the winding are respectively connected are preferably provided on an axial end surface of one of the pair of flanges. .

  According to such a configuration, the winding and the electrode on the substrate can be electrically joined by connecting the electrode portion to the electrode on the circuit. Therefore, it is not necessary to directly connect the end of the winding to the electrode on the circuit, and the coil component can be easily mounted on the circuit.

  In the coil component, the U-shaped core is preferably joined to the drum core with a resin. According to such a configuration, the joining property between the U-shaped core and the drum core can be increased.

  According to the coil component of the present invention, the winding direction of the winding can be concentrated in one direction, and the coil component including the outer core can be reduced in size.

  A coil component according to an embodiment of the present invention will be described with reference to FIGS. The coil component 1 is a component that is surface-mounted on a printed wiring board or the like by reflow soldering or the like and used as a choke coil in various electronic devices.

  As shown in FIG. 1, the coil component 1 includes a drum core 2, a U-shaped core 6, metal terminals 71 and 72, and the like. The U-shaped core 6 is disposed outside the drum core 2, and the U-shaped core 6 and the drum core 2 are in close contact with each other. The metal terminals 71 and 72 are arranged below the drum core 2 and the U-shaped core 6.

  The drum core 2 is made of, for example, a Ni—Zn based magnetic material. The drum core 2 is comprised from the cylindrical core part 3 and a pair of collar parts 41 and 42, as FIG.2 and FIG.3 shows. A winding 5 (FIG. 1) is wound around the core portion 3. The flange portions 41 and 42 are substantially circular discs having the same diameter, and are provided at both axial ends of the core portion 3. The core part 3 and the collar parts 41 and 42 are coaxially arranged.

  A bottom facing portion 4 </ b> A that faces a bottom portion 63 of the U-shaped core 6, which will be described later, is defined on the side surfaces of the flange portions 41, 42 and in close contact with the U-shaped core 6. More specifically, as shown in FIG. 3, a range of θ = about 180 ° about the axis of the drum core 2 is defined as the bottom facing portion 4A. As shown in FIGS. 1 and 5, metal terminals 71 and 72 are fixed to the axial end surface of the core portion 3 of one collar portion 42 with an adhesive.

  The metal terminals 71 and 72 are made of a copper alloy such as phosphor bronze. The pair of metal terminals 71, 72 have a plate-like long shape, and the flange portion is such that the longitudinal direction is substantially parallel to the direction from the axis of the drum core 2 toward the substantially center of the arc of the bottom facing portion 4 </ b> A. 42 is adhered. Edge portions 71A and 72A of metal terminals 71 and 72 are bent downward on the mounting surface side so as to face each other. As the adhesive, for example, a resin mainly composed of an epoxy resin is used.

  The winding 5 shown in FIGS. 1 and 5 is configured by applying a urethane film to a copper wire. Both ends 5A and 5B of the winding 5 have a coating removed for connection to the metal terminals 71 and 72. As the winding 5, for example, a flat or round wire is used.

  The U-shaped core 6 is configured by mixing Ni—Zn-based magnetic substance powder into a resin having thermosetting property or thermoplasticity such as epoxy resin substantially evenly, and magnetic powder is mixed. The resin has a magnetic permeability of about 2% to 5% compared to a core formed by sintering a magnetic material having the same composition. The U-shaped core 6 has a pair of arm portions 61 and 62 extending in parallel and a bottom portion 63 provided on the base end side of the pair of arm portions 61 and 62 and has a substantially U shape. 4 and 5, a curved surface 63A is formed at a position corresponding to the bottom 63 on the inner surface of the U-shaped core 6, and the contour of the curved surface 63A is a substantially semicircular shape. It is formed in a circular arc shape. The radius of curvature of the arc related to the contour of the curved surface 63 </ b> A is substantially equal to the radius of the flange portions 41 and 42. The inner peripheral surface of the U-shaped core 6 has planes 61A and 62A facing each other at positions corresponding to the pair of arm portions 61 and 62, and the planes 61A and 62A bear a parallel positional relationship. ing. The curved surface 63A and the flat surfaces 61A and 62A are smoothly connected to each other.

  Furthermore, the U-shaped core 6 is configured so that the left side portion including the arm portion 61 and the right side portion including the arm portion 62 are symmetrical in the plan view shown in FIG. The front side and the back side are configured symmetrically. Therefore, when attaching the U-shaped core 6 to the drum core 2, it is not necessary to pay attention to the front and back, and workability can be improved.

  Next, an outline of a method for assembling the coil component 1 will be described. First, the metal terminals 71 and 72 are bonded to the lower surface of the flange portion 42 of the drum core 2 so as to be substantially parallel to each other. At this time, the edges 71A and 72A of the metal terminals 71 and 72 are bent in advance downward on the mounting surface side so as to face each other.

  As shown in FIG. 5, the winding 5 is wound around the core portion 3 of the drum core 2, and both end portions 5 </ b> A and 5 </ b> B are in the longitudinal direction of the metal terminals 71 and 72, and other than the bottom facing portion 4 </ b> A of the flange portion 42. It extends toward the metal terminals 71 and 72 from the location, that is, the location that is the open end side opening position of the U-shaped core 6. Since the portion other than the bottom facing portion 4A does not contact the U-shaped core 6 in the flange portion 42, the winding 5 and the U-shape are formed by extending both end portions 5A and 5B from at least the portion other than the bottom facing portion 4A. Interference with the core 6 can be prevented. That is, the degree of freedom of the extension position of the winding 5 from the winding core 3 to the metal terminals 71 and 72 can be increased. The two end portions 5A and 5B extending from the flange portion 42 are routed below the metal terminals 71 and 72 and soldered, and are electrically and mechanically connected to the metal terminals 71 and 72.

  Next, an epoxy resin adhesive is applied to the curved surface 63 </ b> A of the U-shaped core 6, and the U-shaped core 6 is attached to the drum core 2. Specifically, the drum core 2 is inserted between the arm portion 61 and the arm portion 62 with the bottom facing portion 4A of the drum core 2 and the curved surface 63A of the U-shaped core 6 facing each other, and the U-shape A mold core 6 is mounted. By mounting in this way, it is possible to prevent the ends of the arms 61 and 62 and the flat surfaces 61A and 62A from coming into strong contact with the bottom facing portion 4A.

  Even if the arm portions 61 and 62 are in contact with the bottom facing portion 4A, the bottom facing portion 4A is a part of the circumference, so that the tip portions of the arm portions 61 and 62 slide on the surface of the bottom facing portion 4A, and the drum core 2 Can be suitably inserted between the arm portion 61 and the arm portion 62.

  With the drum core 2 inserted between the arm portion 61 and the arm portion 62, the drum core 2 is inserted to the position of the curved surface 63A of the bottom portion 63. Since the bottom facing portion 4A and the curved surface 63A have substantially the same shape, there is no gap between the drum core 2 and the U-shaped core 6 via an adhesive, and the bottom facing portion 4A and the curved surface 63A are closely bonded. The coil component 1 shown in FIG.

  In general, when a closed magnetic circuit is formed using a core formed by sintering, magnetic saturation may occur, and a predetermined inductance value and current value may not be obtained. However, since the magnetic permeability of the U-shaped core 6 according to the present embodiment is low in advance, even if it is configured to be in close contact with the drum core 2, the occurrence of magnetic saturation can be suppressed, and a predetermined inductance value and current value can be obtained. it can.

  Moreover, since the gap is not provided in the coil component 1 which concerns on this Embodiment, a volume can be made small compared with the coil component which provided the conventional gap. Furthermore, since the U-shaped core 6 can be formed smaller than the conventional ring core, the volume of the coil component can be further reduced.

  Moreover, since the drum core 2 and the U-shaped core 6 are joined using an adhesive, the rigidity of the coil component 1 as a whole is increased, and a coil component having higher strength can be provided.

  The coil component according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, in an adhesive that bonds the drum core 2 and the U-shaped core 6, magnetic powder may be mixed in the same manner as the resin that forms the U-shaped core 6.

The perspective view showing the coil components which concern on embodiment of this invention. The side view showing the drum core of the coil components which concern on embodiment of this invention. The top view showing the drum core of the coil components which concern on embodiment of this invention. The top view showing the U-shaped core of the coil components which concern on embodiment of this invention. The disassembled perspective view showing the coil components which concern on embodiment of this invention.

Explanation of symbols

1 .. Coil parts 2.. Drum core 3.. Core part 41, 42.. Eaves part 4 A.. Bottom facing part 5. ..Arms 61A, 62A..Plane 63..Bottom 63A..Curved surface 71A, 72A..Edges 71, 72..Metal terminal

Claims (5)

A drum core having a columnar core part and a pair of flanges provided at both ends of the core part;
A winding wound around the core and having one end and the other end extending out of the drum core;
It is provided on the outside of the drum core, is made of a composite material of a magnetic body and a resin, and has a pair of arm portions extending in parallel and a bottom portion provided on the base end side of the pair of arm portions, and is substantially U-shaped. A U-shaped core formed;
In the cross section orthogonal to the axial direction of the core part, the inner periphery of the U-shaped core facing the drum core is smoothly formed in an arc shape. In the cross section, the outer periphery of the U-shaped core is the pair of arms. A pair of planes arranged in each of the parts and extending in the same direction as the extending direction of the arms, and a plane arranged in the bottom and extending in a direction intersecting the extending direction of the arms, A pair of planes connecting the planes of the pair of arms and the plane of the bottom, respectively .
One end and the other end of the winding are extended from the open end side opening position of the U-shaped core in a state where the U-shaped core is mounted on the drum core. The pair of the collar portion has a bottom face portion facing the inner surface of the bottom portion to which the U-shaped core to the drum core is positioned in the non-opening side of the U-shaped core in a state of being mounted,
The coil component according to claim 1, wherein the contour of the inner surface of the bottom portion and the contour of the bottom facing portion are substantially equal.   The bottom inner contour and the bottom facing contour are each configured in an arc shape, and the curvature radius of the bottom inner contour and the curvature radius of the bottom facing contour are substantially equal. The coil component described.   A pair of electrodes to which the one end and the other end of the winding are respectively connected are provided on an axial end face of one of the pair of flanges. The coil component according to any one of claims 1 to 3.   The coil component according to any one of claims 1 to 4, wherein the U-shaped core is joined to the drum core by a resin.

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