JP5673585B2 - Coil parts - Google Patents

Description

  The present invention relates to a coil component, and more particularly to a terminal electrode structure of a surface mount type coil component.

  With recent miniaturization of electronic devices, high-density mounting is also required for coil components. For example, Patent Document 1 discloses a surface mount type coil component capable of high density mounting.

  The coil component includes a core having a winding core portion and a flange portion, an insulating case in which a housing space for the core is formed, and a terminal that is mechanically fixed to the case with at least a portion exposed to the outside. A metal fitting and a winding (wire) that is connected to the terminal metal fitting and wound around the core portion through the case are provided. The core accommodating space is defined to include a bottom surface substantially parallel to the mounting surface, and the core portion and the flange portion each have a lower surface of the core portion facing the bottom surface and a lower surface of the flange portion. The lower surface of the part is flush with the lower surface of the collar part. A leg portion that projects toward the mounting surface is defined at a position facing the collar portion of the case, and the mounting portion of the terminal fitting is disposed on the leg portion.

JP 2009-117627 A

  In the coil component described above, the connection between the wire and the terminal fitting is realized by thermocompression bonding the tip end portion of the wire on the terminal fitting. When the wire is thermocompression bonded to the terminal fitting, the wire material (Cu) of the wire and the plating film (Ni and Sn) on the surface of the terminal fitting react to form an alloy layer. Here, since the alloy layer has a high melting point, when this portion becomes a solder joint surface when the coil component is mounted on the circuit board, it becomes a factor of reducing the wettability of the solder. In particular, as shown in FIG. 9A, when the position of the tip 20e of the wire 20 to be thermocompression bonded is matched with the end of the terminal surface of the terminal fitting 21, the end of the terminal surface in the wire extending direction is An alloy layer is formed up to the end, that is, in a wide range of the terminal surface, and the alloy layer may hinder the formation of the solder fillet and cause mounting failure.

  In order to solve this problem, as shown in FIG. 9 (b), the tip 20e of the wire 20 may be set inside (near the center) rather than the end of the terminal surface of the terminal fitting. . In this case, the wire 20 drawn from the core portion of the core passes through the terminal surface of the terminal fitting 21 and is drawn forward, and then the wire portion behind the position to be the tip of the wire. The (practical part) is thermocompression bonded to the terminal surface, and the front wire part (see the broken line) needs to be cut and removed. However, if the front wire portion is in contact with the terminal surface of the terminal fitting 21, the wire adheres to the surface of the terminal fitting when the plating film on the surface of the terminal fitting is melted by heat during thermocompression bonding. There is a problem that can not be cut and removed well.

  In order to solve the above problems, a coil component according to the present invention includes a coil formed by winding a wire, a base that supports the coil, and a terminal fitting to which the terminal portion of the coil is connected. , Having a first surface parallel to the extending direction of the terminal portion of the coil, and the terminal fitting having a first terminal portion located on the first surface of the base, The terminal part of the contact part has a first terminal surface that comes into contact with the terminal part, and is located on an extension line of the terminal part, and does not have a terminal surface on the same plane as the first terminal surface. Part.

  According to the present invention, since the end portion of the wire is not pressed against the surface of the terminal fitting during thermocompression bonding, it is possible to avoid the crimping of the end portion of the wire, and reliably and easily cut and remove the wire after thermocompression bonding. be able to.

  In the present invention, the first terminal portion has a step shape including an upper step portion and a lower step portion, the surface of the upper step portion is the first terminal surface of the contact portion, and the surface of the lower step portion Is preferably a second terminal surface provided in the non-contact portion. According to this configuration, it is possible to ensure a large area of the terminal surface on which the solder is mounted. Further, it is not necessary to accurately position the terminal portion of the coil at the time of crimping, and the terminal portion of the wire can be easily crimped.

  In this invention, it is preferable that the said 1st surface of the said base | substrate has a level | step difference surface matched with the level | step difference shape of the said 1st terminal part. According to this structure, the surface of a base | substrate can be made to follow the level | step difference surface of a terminal metal fitting, and the whole terminal metal fitting can be supported reliably.

  In the present invention, the base body has a second surface orthogonal to the first surface, the terminal fitting is L-shaped, and is a second surface located on the second surface of the base body. It is preferable that the device further includes a terminal portion, the second terminal portion is adhesively fixed to the second surface, and the first terminal portion is not adhesively fixed to the first surface. According to this configuration, it is possible to eliminate variations in the height of the terminal fitting due to variations in the amount of adhesive applied.

  In the present invention, it is preferable that a gap is provided between the back surface of the first terminal portion and the first surface of the base body at least in a portion where the non-contact portion is provided. According to this configuration, when the terminal portion of the coil is cut, a cushion at the time of cutting can be provided by the elastic force of the terminal fitting, and thereby the terminal portion of the coil can be cut reliably.

  In this invention, the said base | substrate is a drum core which has a core part around which the said coil is wound, and a pair of collar part provided in the both ends of the said core part, The said terminal metal fitting is provided in the said collar part. It is preferable. According to this configuration, in the surface mount type coil component using the drum core, the solder wettability of the terminal surface to which the wire is connected can be improved, and the reliability of the electrical and mechanical connection can be improved. Can do.

  According to the present invention, an unnecessary portion of the wire after thermocompression bonding can be reliably cut and easily removed. Accordingly, a coil component having a terminal surface with good solder wettability can be realized.

FIG. 1 is a schematic perspective view showing an external configuration of a coil component according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil component of FIG. FIG. 3 is a schematic perspective view showing a state where the coil component of FIG. 1 is turned upside down. FIG. 4 is a schematic perspective view showing the configuration of the drum core 2 and shows a state in which the terminal fittings 6a to 6f are attached. FIG. 5 shows the drum core 2 without the terminal fittings 6a to 6f in a reversed state with the bottom face facing upward. 6A and 6B show a configuration of the flange portion to which the terminal fitting is attached, wherein FIG. 6A is a schematic plan view of the flange portion viewed from the bottom surface side, and FIG. 6B shows the flange portion viewed from the outer side surface side. FIG. FIGS. 7A and 7B are schematic side sectional views showing the shapes of the terminal fittings attached to the flanges 4A and 4B, respectively. FIGS. 8A to 8C are schematic diagrams for explaining a wire thermocompression bonding process using a heater chip. 9A and 9B are schematic views for explaining a conventional coil component.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing an external configuration of a surface mount type coil component according to a first embodiment of the present invention. 2 is an exploded perspective view of the coil component shown in FIG. 1, and FIG. 3 is a schematic perspective view showing a state where the coil component shown in FIG. 1 is turned upside down.

  As shown in FIGS. 1 to 3, the coil component 1 includes a drum core 2, a plate-like core 5, six terminal fittings 6 a to 6 f, and a coil 7 made of a wire wound around the drum core 2. ing. Although not particularly limited, the coil component 1 is a surface-mount type pulse transformer, and the size thereof is about 4.5 × 3.2 × 2.6 mm.

  The drum core 2 is made of, for example, a magnetic material such as Ni—Zn-based ferrite, and includes a core portion 3 around which the coil 7 is wound, and a pair of flange portions 4A and 4B disposed at both ends of the core portion 3. Yes. The plate-like core 5 is also made of a magnetic material such as Ni—Zn ferrite, and is placed on the upper surfaces of the pair of flange portions 4A and 4B and fixed with an adhesive or the like.

  Since the upper surface of the plate-like core 5 is a flat smooth surface, when the coil component 1 is mounted, the smooth surface can be sucked and mounted as a suction surface. Furthermore, it is preferable that the surface of the plate-like core 5 bonded to the upper surfaces of the flange portions 4A and 4B is also a smooth surface. When the smooth surface of the plate-like core 5 is in contact with the flange portions 4A and 4B, both can be securely brought into contact with each other, and a closed magnetic path free from magnetic flux leakage can be formed.

  The terminal fittings 6a to 6f are L-shaped metal pieces extending from the bottom surfaces of the flange portions 4A and 4B to the outer side surfaces. Here, the outer side surface of the collar portion is a surface located on the side opposite to the attachment surface of the core portion 3. These terminal fittings 6a to 6f are preferably portions cut out from a lead frame obtained by processing a single metal plate. The terminal fittings 6a to 6f are bonded and fixed to the drum core 2 in the state of the lead frame, and become independent terminals by being separated from the frame portion. When the terminal fittings 6a to 6f are used, the formation thereof is easier than the plating electrode, which is advantageous in terms of cost in mass production. Furthermore, the positional accuracy when the terminal fittings 6a to 6f are attached can be increased.

  Of the terminal fittings 6a to 6f, three terminal fittings 6a, 6b, 6c are provided on the flange 4A side, and the other three terminal fittings 6d, 6e, 6f are provided on the flange 4B side. Further, of the three terminal fittings 6a, 6b, 6c, the two terminal fittings 6a, 6b are provided on the right side of the flange portion 4A, and the terminal fitting 6c is provided on the left side of the flange portion 4A. A constant insulation interval is provided between them. Similarly, of the three terminal fittings 6d, 6e, 6f, the two terminal fittings 6d, 6e are provided on the right side of the flange portion 4B, and the terminal fitting 6f is provided on the left side of the flange portion 4B. A constant insulation interval is provided between the two.

As shown in FIG. 2, each of the L-shaped terminal fittings 6a to 6f includes a bottom surface portion T _B (first terminal portion) in contact with the bottom surface (first surface) of the flange portions 4A and 4B, and the flange portion. 4A, 4B has a side surface portion T _S (second terminal portion) in contact with the outer side surface (second surface). Then, as shown in FIG. 3, the terminal portion of the coil 7 is thermocompression bonding surface of the bottom portion T _B of the terminal fitting 6 a to 6 f.

  FIG. 4 is a schematic perspective view showing the configuration of the drum core 2 and shows a state in which the terminal fittings 6a to 6f are attached. FIG. 5 shows the drum core 2 without the terminal fittings 6a to 6f in a reversed state with the bottom face facing upward. Further, FIG. 6A is a schematic plan view of the flange portion 4A viewed from the bottom surface side, and FIG. 6B is a schematic plan view of the flange portion 4A viewed from the outer side surface side.

  As shown in FIGS. 4 and 5, the drum core 2 includes a core portion 3 and a pair of flange portions 4 </ b> A and 4 </ b> B disposed at both ends of the core portion 3. The drum core 2 has a rotationally symmetric shape in plan view, and the flange portions 4A and 4B have the same shape. Therefore, FIG. 6 shows only the flange portion 4A, and the illustration of the flange portion 4B is omitted.

As shown in FIG. 4, the flange portion 4A, the upper surface S _T of 4B is a smooth flat surface, thereby the adhesion between the plate core 5 is enhanced. As described above, the flange portion 4A, the plate-like core 5 is spanned Between the upper surface S _T of 4B, thereby substantially closed magnetic path is formed.

As shown in FIGS. 4, 5 and 6 (b), the flange portion 4A, the outer side surface S _S of 4B, low installation area of the terminal fitting 6 a to 6 f, the other regions become the high step surface Yes. Terminal fitting 6a~6f is provided on the lower surface _{S S1} of the outer side _{S S,} the height of the upper surface _{S S2} of the outer side _{S S} is to be substantially flush with the upper surface of the terminal fitting 6a~6f Is formed. In FIG. 6B, the hatched region is the upper step surface S _S2 , and the region without hatching is the lower step surface S _S1 .

5 and as shown in FIG. 6 (a), the flange portion 4A, 4B bottom S _B of a high installation area of the base end of the terminal fitting 6 a to 6 f, is the other area is low step surface ing. That is, an upper step surface S _B2 and a lower step surface S _B1 are provided in the installation area of the terminal fittings 6a to 6f, and most of the non-installation region of the terminal fittings 6a to 6f is the lower step surface S _B1 . The proximal end of the bottom portion _{T B} of the terminal fitting 6a~6f is provided on the upper surface _{S B2} of the bottom surface _{S B} of the flange 4A, 4B, the corners of the bottom portion _{T B} of the terminal fitting 6a~6f parts side is provided on the lower surface _{S B1} of the bottom surface _{S B} of the flange 4A, 4B. In FIG. 6A, the hatched region is the upper step surface _SB2 , and the region without hatching is the lower step surface _SB1 .

  7 (a) and 7 (b) are schematic side sectional views showing the shapes of the terminal fittings 6a to 6f attached to the flanges 4A and 4B, respectively, and (a) is a schematic side view including the entire drum core, (B) is the elements on larger scale of the terminal metal fitting by the side of the collar part 4A. In addition, the structure by the side of the collar part 4B is the same as the side of the collar part 4A.

FIGS. 7 (a) and (b), the bottom portion _{T B} and a side portion of the L-shaped terminal fittings 6 a to 6 f _{T S} is a flange 4A, 4B bottom _{S B} (first surface) of And the outer side surface S _S (second surface). Here, the side surface portion T _S is bonded and fixed by an adhesive 11 to the outer side surface S _S of the flange portion, a bottom portion T _B is not bonded to the bottom surface S _B of the flange. According to this configuration, it is possible to eliminate the height variation of the bottom T _B of the terminal fitting 6a~6f due to variations in coat-weight of the adhesive.

Bottom portion T _B of the terminal fitting 6a~6f the terminal portion of the coil 7 is joined has a stepped shape. The flange portion 4A, the stepped surface of the bottom _{S B} of 4B has a combined shape stepped shape of the terminal fitting 6 a to 6 f.

Bottom portion _{T B} of the terminal fitting 6a~6f is a flange 4A, an upper portion _{T B1} provided inside the side surface side of the 4B (core portion 3 closer), the flange portion 4A, the outer side _{S S} side of the 4B made from the lower portion _{T B2} provided. Here, the upper step portion T _B1 is a portion (contact portion) that provides a terminal surface (upper step surface S _U ) that contacts the terminal portion of the coil 7, and the lower step portion T _B2 does not contact the terminal portion of the coil 7. It is a site | part (non-contact part) which provides a terminal surface (lower stage surface _SL ). That is, the lower portion T _B2 does not have a terminal surface on the upper surface S _U and the same plane.

Upper surface S _U of the bottom T _B of the terminal fitting 6a~6f receives a pressing force to the terminal portion of the coil 7 at the time of thermocompression bonding to provide a "contact face". Further, the lower surface S _L of the bottom portion T _B of the terminal fitting 6a~6f may escape the pressure contact force to the terminal portion of the coil 7 provides a "non-contact face." By having a stepped surface which is the bottom portion _{T B} of the terminal fitting 6a~6f consisting upper surface _{S U} and the lower surface _{S L,} the terminal portion of the coil 7, extends in the coils in the bottom portion of the terminal fitting 6a~6f It is possible to avoid thermocompression bonding over the entire width of the direction. Therefore, it is possible to secure a wide area where the alloy layer is not formed by the reaction between the wire and the plating film, and the wire can be cut and removed reliably and easily.

Rear face flange portion 4A of the lower portion _{T B2} of the bottom portion _{T B} of the terminal fitting 6 a to 6 f, between the lower surface _{S B1-side} surface of 4B, it is preferable that a clearance _{d 1} is provided. If such a gap d ₁ is provided with a can, when cutting the terminal portion of the coil 7 after thermocompression bonding to the cutter, it is possible to provide a cushion by the elastic force of the terminal fitting 6 a to 6 f. Therefore, the terminal portion of the coil 7 can be reliably cut.

In FIG. 7 (b), the only the side portion _{T S} is bonded and fixed by an adhesive 11, two side portions _{T S} and the bottom portion _{T B} of the lower portion _{T B2} (part of the gap _{d 1)} May be bonded and fixed. In this case, the upper stage _TB1 is not bonded. According to this structure, while preventing variation in height of the bottom T _B of the terminal fitting 6 a to 6 f, it is possible to further increase the bonding strength.

  FIGS. 8A to 8C are schematic diagrams for explaining the thermocompression bonding process of the terminal portion of the coil 7.

  As shown to Fig.8 (a), in the thermocompression bonding process, the terminal part of the coil 7 wound by the core part 3 of the drum core 2 is wired on corresponding terminal metal fittings 6a-6f. The terminal portion of the coil 7 passes through the terminal fittings 6a to 6f and is drawn to the outside of the flange portions 4A and 4B, and extends substantially parallel to the bottom surfaces of the flange portions 4A and 4B.

Next, as shown in FIG.8 (b), the terminal part of the coil 7 is thermocompression-bonded to the surface of the terminal metal fittings 6a-6f using the heater chip 12. FIG. Wire portion located above the upper surface S _U of the bottom T _B of the terminal fitting 6a~6f is sandwiched between the heater chip 12 and the upper surface S _U, the terminal surface in pressure contact force of the high temperature heater chip 12 The wire wire (Cu) and the plating film (Ni and Sn) on the terminal surface are alloyed to obtain a sufficient bonding force.

On the other hand, the wire portion located above the lower surface _{S L} of the bottom portion _{T B} of the terminal fitting 6a~6f is escaped into the gap _{d 2} between the heater chip 12 and the lower surface _{S L,} as the upper surface _{S U} A sufficient pressure contact force is not applied. Therefore, thermocompression bonding to the terminal surface of the wire portion can be avoided.

As shown in FIG.8 (c), the terminal part of the coil 7 heat-pressed on the terminal metal fittings 6a-6f in this way is cut | disconnected by the cutter 13, and the length is adjusted. At this time, the cutting position of the coil 7 is in the vicinity of the steps of the terminal fittings 6a to 6f. Even when the end portion of the coil 7 is cut, the extra wire portion 7r of the wire that has not been thermocompression bonded is not fixed to the terminal surface, or even if it is fixed to the terminal surface by a plating film melted during thermocompression bonding. Since the fixing force is weak, it peels off with a little force. As a result, only the wire surface of which the upper surface S _U of the bottom T _B of the terminal fitting is thermocompression bonding, a state the wire is not in the lower surface S _L.

In the upper surface S _U, around the wire becomes a solder having poor wettability region by alloying, more about the present or areas not alloyed, this region contributes to the solder connection. On the other hand, the lower surface S _L is absent wire, the solder wettability of the good region. The lower surface S _L is a portion in contact with the side surface portion T _S of the terminal fitting, at the time of surface mounting, a portion contributing to the formation of the solder fillet with the side surface portion T _S. Therefore, when such a coil component 1 the surface mounting, can increase the solder wettability of the terminal fitting 6 a to 6 f, the solder fillet reliably from the lower portion T _B2 of the terminal toward the side surface portion T _S Can be formed. Therefore, the reliability of the electrical and mechanical connection of the coil component 1 can be improved.

  As described above, the coil component 1 according to the present embodiment is provided with a stepped surface that avoids contact with the tip of the coil 7 on the terminal surfaces of the terminal fittings 6a to 6f to which the terminal portion of the coil 7 is joined. Therefore, it is possible to avoid the tip portion of the wire from being thermocompression bonded to the terminal surface. Therefore, the wire can be cut and removed reliably after thermocompression bonding.

  Moreover, in this embodiment, since the non-contact part with the terminal part of a wire is an electrode surface lower than a contact part, the electrode surface of a terminal metal fitting can be ensured widely. Therefore, high accuracy is not required for positioning of the terminal portion of the coil, and the terminal portion of the wire can be easily thermocompression bonded.

Further, in the present embodiment, the flange portion 4A of the drum core 2 to the terminal fitting 6a~6f is attached, since the stepped surface is provided on the bottom surface S _B of 4B, to enhance the adhesion of the terminal fitting and its mounting surface And the terminal fitting can be reliably supported.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention, and it goes without saying that these are also included in the present invention. .

  For example, in the above-described embodiment, a horizontal drum core having a winding core portion around which the coil is wound and a pair of flange portions provided at both ends thereof is used as a base around which the coil is wound. A vertical drum core may be used. The number of terminal fittings is not particularly limited. Further, in the above embodiment, the terminal fitting is directly bonded to the surface of the drum core. However, the drum core may be accommodated in a resin case (bobbin) and the terminal fitting may be attached to the surface of the resin case.

  Moreover, in the said embodiment, although the non-contact part is implement | achieved by the level | step difference surface, the notch part by which a part of terminal metal fitting located on the extension line of the terminal part of a wire was stamped may be sufficient. Also in this case, since the step is generated by the thickness of the terminal fitting, it is possible to avoid the tip portion of the wire from being thermocompression bonded to the terminal surface. Therefore, the wire can be cut and removed reliably after thermocompression bonding.

DESCRIPTION OF SYMBOLS 1 Coil component 2 Drum core 3 Core part 4A, 4B Eaves part 5 Plate-shaped core 6a-6f Terminal metal fitting 7 Coil 7r Coarse line part 11 Adhesive 12 Heater chip 13 Cutter 20 Wire 20e Tip part 21 Terminal metal fitting d ₁ Crevice d ₂ the outer side of the outer side surface S _S1 flange portion of the lower surface S _S flange portion of the bottom surface portion of the upper surface S _L terminal fitting of the bottom surface of the lower surface S _B2 flange portion of the bottom surface of the bottom surface S _B1 flange portion of the gap S _B collar portion the upper portion T _B2 terminal fitting of the bottom portion of the bottom portion T _B1 terminal fitting of the upper surface T _B terminal fitting of the bottom portion of the upper surface S _U terminal fittings of the upper surface S _T flange portion of the outer side surface of the lower surface S _S2 flange portion side portions of the lower portion T _S terminal fitting of the bottom part

Claims (5)

A coil formed by winding a wire;
A base that supports the coil;
A terminal fitting to which the terminal portion of the coil is connected;
The base body has a first surface parallel to the extending direction of the terminal portion of the coil,
The terminal fitting has a first terminal portion located on the first surface of the base body and solder-connected to the circuit board,
The first terminal portion is
A contact portion having a first terminal surface in contact with the terminal portion;
A non-contact portion that is located on an extension line of the terminal portion and does not have a terminal surface on the same plane as the first terminal surface;
The first terminal portion has a step shape including an upper step portion and a lower step portion,
The surface of the upper part is the first terminal surface of the contact part,
Surface of the lower portion, the coil component, wherein the a second terminal surface provided on the non-contact portion. 2. The coil component according to claim 1, wherein the first surface of the base has a stepped surface matching a stepped shape of the first terminal portion. The substrate has a second surface orthogonal to the first surface;
The terminal fitting is L-shaped, and further includes a second terminal portion located on the second surface of the base body,
The second terminal portion is adhesively fixed to the second surface,
The coil component according to claim 1 or 2 , wherein the first terminal portion is not bonded and fixed to the first surface. The coil component according to claim 3 , wherein a gap is provided between the back surface of the first terminal portion and the first surface of the base body at least in a portion where the non-contact portion is provided. The base is a drum core having a core portion around which the coil is wound and a pair of flange portions provided at both ends of the core portion,
The coil component as described in any one of Claims 1 thru | or 4 with which the said terminal metal fitting is provided in the said collar part.

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