JP4203958B2 - Surface mount type coil components - Google Patents

Description

  The present invention relates to a surface mount type (SMD type) coil component such as an EMC filter in which a winding is provided on a magnetic or non-magnetic core, and is particularly suitable for automobiles having a severe use environment, and a drum type having a winding. The present invention relates to a surface-mounted coil component that prevents peeling of a cover core due to deterioration of an adhesive when the cover core is bonded and integrated with the core, thereby improving cover core mounting strength and reliability.

  As a conventional surface mount type coil component, a substantially U-shaped terminal fitting having a retaining portion as an end electrode is used, and after fitting the terminal fitting to the end of the magnetic core, a winding is wound around the magnetic core. There is a configuration in which the winding terminal is connected to a connecting portion provided in the terminal fitting, and a flat cover core is further attached by adhesion.

  In addition, an electrode part is provided on the end face of the magnetic core by printing or plating, winding is performed on the magnetic core, the winding terminal is connected to the electrode part, and a flat cover core is adhesively attached and surface mounted. A configuration of a mold coil component was also known.

  In addition, as disclosed in Patent Document 1 below, an electrode is provided on the bottom surface of the magnetic core, a terminal of a winding wound around the magnetic core is connected to the electrode on the bottom surface, and a flat cover core There is also known a configuration in which a surface mount type coil component is attached by bonding.

JP 2003-168611 A

  By the way, since the conventional surface mount type coil component shown in the above-mentioned Patent Document 1 has a flat cover core mounted on the flange of the drum-shaped magnetic core simply by bonding, the adhesive holding force is a characteristic of the adhesive. It was influenced by. The adhesive strength of the adhesive tends to decrease in environmental tests such as moisture resistance and thermal shock. From the viewpoint of reliability, a configuration that relies only on the adhesive strength of the adhesive is not preferable. In addition, the adhesive strength of the adhesive depends on the surface state and the application state of the member to be bonded, and there is a drawback that it lacks stability. In addition, the adhesive strength depends on the storage and use time of the adhesive, the curing temperature and the time, and it takes time and effort to manage the adhesive in an optimum state.

  The present invention has been made in view of the above problems, and by devising the cover core mounting structure and making it a structure that does not rely only on the adhesive strength of the adhesive, even when the usage environment of automobiles and the like is severe, An object of the present invention is to provide a surface mount type coil component capable of preventing peeling of a cover core and improving reliability.

In order to achieve the above object, a surface mount type coil component according to the present invention is provided with a winding on the core portion of a magnetic or nonmagnetic core having plate-like end portions on both sides of the core portion, and the winding The end of the wire is provided on the upper surface of the coil component main body connected to the connecting portion of the terminal fitting provided as an end electrode on the plate-like end, and the surface facing the mounting surface of the plate-like end A structure having a cover core,
The terminal fitting is parallel to the mounting surface of the plate-like end portion and is fitted toward the core portion, and is provided at four corners of the coil component main body, the mounting surface of the plate-like end portion, and the mounting surface The connecting portion is integrally formed at the portion of the terminal fitting along the surface facing the mounting surface of the plate-like end portion. ,
Notches are provided at the four corners of the cover core, and convex portions or concave portions are formed on the side surfaces of the notches ,
The connecting portion is adjacent to or close to a convex portion or a concave portion on a side surface of the notch , and an adhesive is provided in a region including the convex portion or the concave portion and the connecting portion, and the adhesive is It has also entered into the lower part of the said connection part .

  In the case of the conventional example, since the flat cover core is simply attached to the collar portion of the core having the windings by adhesion, the adhesive holding force depends on the characteristics of the adhesive. In addition, the adhesive strength of the adhesive tends to decrease in environmental tests such as moisture resistance and thermal shock, and the adhesive strength depends on the surface condition and application state of the adherend, and is not stable. was there. In addition, the adhesive strength depends on the storage and use time of the adhesive, the curing temperature and time, and it takes time and effort to manage it in the best condition.

  The above-described surface mount type coil component according to the present invention can hold the cover core mechanically and structurally with respect to the core provided with the winding even when the adhesive force of the adhesive is reduced or eliminated. Because the cover core never peels off, it has high durability and reliability against the environment such as humidity, heat, vibration, etc. Thus, it is possible to realize an inexpensive surface mount coil component with high cover core mounting reliability.

In another surface mount type coil component according to the present invention, a winding is provided on the core portion of a magnetic or non-magnetic core having plate-like end portions on both sides of the core portion, A coil component main body connected to a connecting portion of a terminal fitting provided as an end electrode on a plate-like end portion, and a cover core provided on the upper surface of the surface facing the mounting surface of the plate-like end portion Configuration,
The terminal fitting is parallel to the mounting surface of the plate-like end portion and is fitted toward the core portion, and is provided at four corners of the coil component main body, the mounting surface of the plate-like end portion, and the mounting surface A locking portion separate from the connecting portion in the portion of the terminal metal fitting that is along the surface facing the mounting surface of the plate-like end portion and the surface facing the mounting surface. Is formed by bending
Notches are provided at the four corners of the cover core, and convex portions or concave portions are formed on the side surfaces of the notches,
The locking portion is adjacent to or close to a convex portion or a concave portion on a side surface of the cutout portion, and an adhesive is provided in a region including the convex portion or the concave portion and the locking portion, and the adhesive is It has also entered into the lower part of the said latching | locking part, It is characterized by the above-mentioned .

  The locking portion can reliably perform the function of locking the adhesive, and can contribute to improving the reliability of fixing the cover core.

  It is preferable that the convex part or concave part on the cover core side is at a substantially central position of the thickness of the cover core.

  It is desirable that the gap between the opposing surfaces of the magnetic or nonmagnetic core and the cover core is not blocked by an adhesive.

  The surface mount type coil component of the present invention can hold the cover core mechanically and structurally with respect to the core provided with the winding even when the adhesive strength of the adhesive is reduced or eliminated. Since it does not peel off, it has high durability and reliability against the environment such as humidity, heat, vibration, etc., is hardly affected by the surface condition and application state of the adherend, and is easy to manage and covers An inexpensive surface-mounting coil component with high core mounting reliability can be realized.

  Hereinafter, as the best mode for carrying out the present invention, an embodiment of a surface mount type coil component will be described with reference to the drawings.

  A first embodiment of a surface mount coil component according to the present invention will be described with reference to FIGS. FIG. 1 (A) shows the structure of the retaining portion on the magnetic core side and the terminal fitting side when the terminal fitting is attached to the magnetic core (magnetic core) of the surface mounting type coil component, and FIG. 1 (B) shows the surface mounting type. A state in which a terminal metal fitting is attached to the magnetic core of the coil component, FIG. 5C shows a state in which the magnetic core is wound and the winding terminal is locked to the terminal metal fitting, and FIG. (E) shows a state in which the cover core is disposed on the upper surface of the magnetic core, and (F) shows a state in which the cover core is fixed to the upper surface of the magnetic core with an adhesive. FIG. 2A is a side view showing a cover core attached to the magnetic core with an adhesive, and FIG. 2B is a cross-sectional view.

  A square drum type ferrite core (hereinafter referred to as a ferrite drum core) 1 as a magnetic core used here has a plate-like end of the core on both sides of the core 2 as shown in FIGS. 1 (A) and 1 (B). A rectangular collar 3 is formed as a part.

  The terminal metal fitting 10 serving as an end electrode is a copper alloy such as phosphor bronze or brass, and is bent into a substantially U-shape, as shown in FIGS. 1 (A) and 1 (B). The structure has an upper surface portion 10b and a bottom surface portion 10c (to be a mounting side portion), and the upper surface portion 10b and the bottom surface portion 10c facing each other are connected by the side surface portion 10a. In other words, the shape is along the mounting surface of the rectangular flange 3 as the plate-like end, the surface facing the mounting surface, and the surface connecting them. Further, as shown in FIG. 1A, the inner surface of the top surface portion 10b and the bottom surface portion 10c is formed with a potch portion (a protruding portion protruding toward the inner surface side) 11 as a bracket side retaining portion, and the rectangular flange portion. 3 can be fitted into a recess 5 as a core-side retaining portion formed on the upper and lower surfaces (the mounting surface and the surface facing the mounting surface). Further, the upper surface portion 10b is integrally formed with a connecting portion 12 formed of an inverted L-shaped bent portion. That is, the connecting portion 12 is formed by a part of the terminal fitting 10, and the connecting portion 12 is open toward the distal end of the rectangular flange 3 for the convenience of inserting the winding wire 26 ( It may be open in the direction opposite the tip direction.)

  As shown in FIG. 1B, the terminal metal fitting 10 is fitted to the mounting surface of the rectangular flange 3 and is fitted toward the core 2 and is wound to form a ferrite drum core 1 that becomes a coil component body. Are provided at the four corners (the left and right end positions of both square flanges 3). When the terminal fitting 10 is mounted vertically at the left and right end positions of the rectangular flange 3 as shown in FIG. 1B, the concave portion 5 as the core side retaining portion and the potch portion 11 as the metallic side retaining portion, By fitting, the terminal metal fitting 10 can be prevented from coming off from the rectangular flange 3. In addition, it attaches so that the bottom face part 10c of the terminal metal fitting 10 may be located in the mounting surface side of the square collar part 3, and the upper surface part 10b of the terminal metal fitting 10 may be located in the upper surface side which is the other side of a mounting surface.

  After fitting the terminal fitting 10 to the rectangular flange 3 as described above, an insulation-coated wire such as urethane wire is used around the core portion 2 of the ferrite drum core 1 as shown in FIG. A pair of windings 25A and 25B are wound. For example, in the case of a common mode coil component such as a common mode filter, the winding core 25 is wound with the same number of turns so that the winding 25A is a lower layer and the winding 25B is an upper layer. The terminal wire 26 of the winding 25 </ b> A is temporarily crimped and fixed by hooking on the connecting portion 12 of the terminal fitting 10 on the left side of the rectangular flange 3 and caulking the connecting portion 12. Similarly, the terminal wire 26 of the winding 25 </ b> B is hooked on the connecting portion 12 of the terminal fitting 10 on the right side of the rectangular flange 3 and crimped and temporarily fixed by caulking the connecting portion 12.

  Thereafter, the connection between the wire terminal and the connecting portion 12 of the terminal fitting 10 is performed by laser welding or arc welding, and a part of the connecting portion 12 is melted as a welded portion P as shown in FIG. The connecting portion 12 and the conductor portion (copper wire portion) of the wire 26 are mechanically and electrically connected. Thereby, a coil component main body is completed. A part of the connecting portion 12 remains without being melted after welding.

  As shown in FIGS. 3A, 3B, and 3C, the cover core 20 has a flat plate shape, and is made of the same material as the drum core 1, or a nonmagnetic ceramic or resin plate. In order to avoid the connecting portion 12 (in order to avoid the cover core 20 from floating when the lower surface of the cover core 20 hits the connecting portion 12), notches 21 are provided at the four corners of the cover core 20. Further, a stepped convex portion 22a for locking an adhesive used in an adhesion process described later is formed on one side surface of the two side surfaces of each notch portion 21. It is preferable that the convex portion 22a on the cover core side is formed at a substantially central position in the thickness of the cover core 20 because it is not necessary to distinguish the front and back of the cover core 20 during assembly.

  As shown in FIG. 1 (E), the cover core 20 is placed on the upper surface of the rectangular flange 3 of the ferrite drum core 1 of the coil component body (the surface facing the mounting surface) while avoiding the connecting portion 12 (both The rectangular hook 3 is placed so as to bridge, and the lower surface of the cover core 20 is brought into contact with the upper surface of the rectangular hook 3 exactly. In this state, the connecting portion 12 on the upper surface of the terminal fitting 10 provided at the left and right end portions of the rectangular flange portion 3 serving as the core plate-like end portion faces or is adjacent to the notch portion 21 of the cover core 20. The step-like convex portion 22 a formed on one side surface of the portion 21 is in a positional relationship close to the connecting portion 12.

  Then, as shown in FIG. 1 (F) and FIGS. 2 (A) and 2 (B), the rectangular baskets exposed to the side surface portion of the cutout portion 21 and the cutout portion 21 so as to include at least the connecting portion 12 and the stepped convex portion 22a. The adhesive 24 is applied over the upper surface of the part 3. At this time, as shown in FIG. 2B, the adhesive 24 enters the lower side of the connecting portion 12 formed by folding back from the upper surface portion 10 b of the terminal fitting 10, and the stepped convex portion 22 a is formed in the adhesive 24. The adhesive 24 is cured in the rushed state. That is, structurally, both the connecting portion 12 and the stepped convex portion 22a of the cover core 20 have a function of locking the adhesive 24, and the cover core 20 is cured even when the adhesive force of the adhesive 24 is reduced or lost. The drum 24 is integrally held on the drum core 1 side through the adhesive 24. The adhesive 24 does not need to be applied between the opposing surfaces of the rectangular flange 3 and the cover core 20, and the space between the opposing surfaces is not blocked by the adhesive (the adhesive is interposed between the opposing surfaces). Preferably not).

  As a result, a surface mount type coil component in which a pair of windings 25A and 25B are provided on the drum core 1 to form a coil component main body and the cover core 20 is fixed to the upper surface of the drum core 1 is obtained. The purpose of providing the cover core 20 is to make the structure suitable for improving the magnetic characteristics and attracting and holding by the suction nozzle of the chip component mounting machine when the cover core 20 is made of the same magnetic material as the drum core 1. Further, when the cover core 20 is a non-magnetic material, it is provided in order to obtain a structure suitable for the latter adsorption holding.

  FIG. 4 shows the results of a tensile strength test after a PCT (pressure cooker) test, (A) is a conventional product in which a flat cover core is simply bonded to a drum core, and (B) is a tensile strength test of a prototype according to this embodiment. It is a result. In the conventional product shown in FIG. 4A, the initial value (before the PCT test) is about 25 N, but it is reduced to about 10 N after the 20-hour PCT test, and the possibility of the cover core falling off cannot be ignored. In the prototype according to the present embodiment shown in FIG. 4B, the initial value (before the PCT test) was about 50 N, but the value dropped to about 30 N after the 20-hour PCT test, but the tensile strength remained sufficiently high. It can be seen that the cover core can be reliably prevented from falling off.

  According to the first embodiment, the following effects can be obtained.

(1) In the configuration in which the cover core 20 is provided on the upper surface of the rectangular flange 3 of the ferrite drum core 1 on the coil component main body side, stepped protrusions 22a are formed on one side surface of the notches 21 formed at the four corners of the cover core 20. In addition, a terminal fitting 10 is provided as an end electrode on the rectangular flange 3 which is a plate-like end portion of the drum core 1 and a connecting portion 12 is formed on the upper surface side of the terminal fitting 10, and the protruding portions 22 a close to each other are formed. Since the adhesive 24 is provided in the region including the connecting portion 12 and the cover core 20 is bonded to the drum core 1, the stepped convex portion 22 a and the connecting portion 12 both function to hold the adhesive 24. Even if the adhesive force of the adhesive 24 decreases or disappears, the cover core 20 can be prevented from falling off the drum core 1.

(2) Since the stepped convex portion 22a on the cover core side is located at a substantially central position in the thickness of the cover core 20, it is not necessary to manage the front and back of the cover core 20 during assembly.

(3) Since the cover core 20 has the cutout portions 21 formed at the four corners, the connecting portion 12 formed on the upper surface portion 10b of the terminal fitting 10 can be avoided, and the lower surface of the cover core 20 is the upper surface of the rectangular flange portion 3. It is possible to prevent the adhesive from being interposed between the opposing surfaces of the upper surface of the rectangular flange 3 and the lower surface of the cover core by providing the adhesive 24 at the portion of the notch 21. For this reason, when the cover core 20 is also made of a magnetic material, the magnetic characteristics can be improved. Further, since the cutout portions 21 are provided at the four corners of the cover core 20, the cover core 20 is not easily chipped.

(4) Even when the environment of use such as an automobile is severe, the terminal fitting 10 is fitted to the rectangular flange 3 of the drum core 1, and the structure between the drum core 1 and the mounting board on the other side is greatly absorbed. Problems such as electrode peeling, solder cracks, and core cracks are eliminated. Further, since the wire 26 is mechanically and electrically connected to the connecting portion 12 of the terminal fitting 10 by laser welding or arc welding, the wire connection portion is not melted and deteriorated by heat during mounting or the like. . As a result, in combination with the effect of preventing the cover core 20 from falling off, it is possible to realize a surface-mounted coil component capable of improving the reliability of the mounting portion and the connecting portion.

  In the first embodiment, the terminal fitting 10 is fitted to the rectangular flange 3 in the direction along the axial direction of the core 2, but the terminal fitting 10 is lateral to the rectangular flange 3. It is good also as a structure fitted toward the core part 2 in the direction orthogonal to the axial direction of the core part 2 from.

  5 (A), (B), and (C) are flat cover cores 20 used in Embodiment 2 of the present invention, and the step is formed on the other side surface of the two side surfaces of the cutout portion 21 formed at the four corners. A convex portion 22b is formed. In this case, only the position of the step-like convex portion 22b is different, and the surface-mounted coil component similar to that of the first embodiment is obtained in the steps of FIGS.

  6A, 6B, and 6C are flat cover cores 20 used in Embodiment 3 of the present invention, and stepped protrusions 22c are formed over two side surfaces of cutouts 21 formed at four corners. Forming. In this case, only the position of the stepped convex portion 22c is different, and the same surface-mounted coil component as that of the first embodiment is obtained in the steps of FIGS.

  FIG. 7 shows a terminal fitting 10 used in Embodiment 4 of the present invention, in which a connecting portion 12 is formed on the upper surface portion 10b, and an engaging portion for engaging an adhesive separately from the connecting portion 12 13 is formed by an inverted L-shaped bent portion with respect to the upper surface portion 10b. In addition, the same code | symbol was attached | subjected to FIG.

  In this case, since the locking portion 13 is provided on the upper surface of the terminal fitting 10 separately from the connecting portion 12, even if the connecting portion 12 is melted and deformed when the winding terminal is connected by welding, the locking portion 13 is irrelevant to welding and does not melt and deform, and the locking portion 13 can bite into the adhesive to reliably hold the adhesive, as shown in FIGS. 1 (A) to (F). In the process, the same surface-mounted coil component as in the first embodiment is obtained.

  In each embodiment, the ferrite core is exemplified as the magnetic core. However, a core made of another magnetic material may be used, and a nonmagnetic ceramic core or the like may be used particularly when high frequency characteristics are required.

  Further, in each embodiment, instead of the convex portion for locking the adhesive, it may be a concave portion for locking the adhesive, and has a function of mechanically locking and holding the adhesive. Any shape is acceptable.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a first embodiment of a surface mount type coil component according to the present invention, where (A) is an exploded perspective view showing the structure of a retaining portion on the magnetic core side and terminal fitting side, and (B) is a surface mount type coil component. The perspective view which shows the state which attached the terminal metal fitting to the magnetic core of FIG., (C) is the perspective view which shows the state which gave the coil | winding to the magnetic core and locked the coil | winding terminal to the terminal metal fitting, (D) is a connection part The perspective view which shows the state which welded the cover core, (E) is the perspective view which shows the state which mounted the cover core on the magnetic core, (F) is the perspective view which shows the state which bonded and integrated the cover core on the magnetic core. is there. It is the attachment structure part by the adhesive agent of the cover core to the magnetic core in Embodiment 1 of this invention, Comprising: (A) is a side view, (B) is sectional drawing. It is a cover core in Embodiment 1 of this invention, Comprising: (A) is a top view, (B) is a front view, (C) is a side view. It is the tensile strength test result after a PCT test, (A) is a conventional product, (B) is a graph which shows the tensile strength of the prototype which concerns on this Embodiment 1. FIG. It is a cover core used in Embodiment 2 of this invention, Comprising: (A) is a top view, (B) is a front view, (C) is a side view. It is a cover core used in Embodiment 3 of this invention, Comprising: (A) is a top view, (B) is a front view, (C) is a side view. It is an expansion perspective view of the terminal metal fitting used in Embodiment 4 of this invention.

Explanation of symbols

1 Ferrite drum core 2 Winding core 3 Square flange 5 Recess
21 notch
22a , 22b, 22c Convex portion 10 Terminal fitting 10a Side surface portion 10b Top surface portion 10c Bottom surface portion 11 Potch portion 12 Connection portion 13 Locking portion 20 Cover core 25A, 25B Winding 26 Wire

Claims (4)

A terminal fitting in which a winding is provided on the core part of a magnetic or non-magnetic core having plate-like end portions on both sides of the core part, and an end electrode of the winding is provided on the plate-like end part as an end electrode a surface-mount coil component having a coil component body that is connected to the connecting wire portion, and a cover core provided on the upper surface of the surface facing the mounting surface of the plate-shaped end portion,
The terminal fitting is parallel to the mounting surface of the plate-like end portion and is fitted toward the core portion, and is provided at four corners of the coil component main body, the mounting surface of the plate-like end portion, and the mounting surface The connecting portion is integrally formed at the portion of the terminal fitting along the surface facing the mounting surface of the plate-like end portion. ,
Notches are provided at the four corners of the cover core, and convex portions or concave portions are formed on the side surfaces of the notches ,
The connecting portion is adjacent to or close to a convex portion or a concave portion on a side surface of the notch , and an adhesive is provided in a region including the convex portion or the concave portion and the connecting portion, and the adhesive is A surface-mounting coil component that is also inserted under the connecting portion . A terminal fitting in which a winding is provided on the core part of a magnetic or non-magnetic core having plate-like end portions on both sides of the core part, and an end electrode of the winding is provided on the plate-like end part as an end electrode A surface mount type coil component having a coil component main body connected to the connecting portion and a cover core provided on the upper surface of the surface facing the mounting surface of the plate-like end,
The terminal fitting is parallel to the mounting surface of the plate-like end portion and is fitted toward the core portion, and is provided at four corners of the coil component main body, the mounting surface of the plate-like end portion, and the mounting surface A locking portion separate from the connecting portion in the portion of the terminal metal fitting that is along the surface facing the mounting surface of the plate-like end portion and the surface facing the mounting surface. Is formed by bending
Notches are provided at the four corners of the cover core, and convex portions or concave portions are formed on the side surfaces of the notches,
The locking portion is adjacent to or close to a convex portion or a concave portion on a side surface of the cutout portion, and an adhesive is provided in a region including the convex portion or the concave portion and the locking portion, and the adhesive is A surface-mounting coil component that is also provided below the locking portion . The notch side according to claim 1 or 2 surface mount coil component according projections or recesses is in the approximate center of the thickness of the cover core of.   The surface-mounted coil component according to claim 1, 2, or 3, wherein a gap between the opposing surfaces of the magnetic or nonmagnetic core and the cover core is not blocked by an adhesive.

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