JP2003257749A - Surface mounting coil apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil apparatus having a simple structure which can be subjected to a surface mounting on a printed wiring board by a simple process. <P>SOLUTION: In a surface-mounting coil apparatus, an annular core 1 is provided on a pedestal 3, and a wire 21 having a circular section is so wound around the core 1 as to mount a coil 2 on the core 1. After forming two flat lead portions 22, 22 having respectively rectangular sections in both the ends of the wire 21 forming the coil 2, both the flat lead portions 22, 22 are extended from the front-surface side of the pedestal 3 to its rear-surface side. Further, both the flat lead portions 22, 22 are so bent in their easily bendable directions that they are extended along the rear surface of the pedestal 3 and their ends 23, 23 are fastened to the pedestal 3. Out of both the flat lead portions 22, 22 extended along the rear surface of the pedestal 3, junction surfaces 24, 24 to be joined to the surface of a printed wiring board are formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil device installed in a rectifier circuit, a noise prevention circuit, a resonance circuit, etc. in various AC devices.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 16, a coil device of this type has a round shaft wire having a circular cross section around an annular core (1).
It is constructed by mounting a coil (5) formed by winding (51), and has a disk-shaped pedestal (6) as a structure for stable mounting on a circuit board. The core (1) is formed by covering an outer peripheral surface of an annular core piece (not shown) with an insulating layer. For example, in the case of a choke coil, a magnetic gap is formed in the core piece. Both ends of the round shaft conductor (51) forming the coil (5) penetrate the pedestal (6) and project in the same direction to form a pair of lead portions (52) (52). The base (6) is fixed to the core (1) by a method such as adhesion.

As shown in FIG. 17, a printed wiring board (7) on which the above-mentioned coil device is to be mounted has a pair of round holes () through which a pair of lead portions (52) (52) of the coil (5) should pass. 71) (71) is opened, and a metal layer (72) is formed on the opening edge of the round hole (71).
Are formed. In the coil device mounting process,
As shown in FIG. 18A, the pair of lead portions (5
2) Insert the (52) into the round holes (71) (71) of the printed wiring board (7), and solder (73) to the base of the pair of lead parts (52) (52) as shown in FIG. It is fused and soldered to the printed wiring board (7). After that, a pair of lead parts (52) (52) as shown in FIG.
Cut off the excess tips (52a) (52a) of the. This completes the mounting process.

[0004]

However, in the conventional coil device, the distance between the pair of round holes (71) (71) to be opened in the printed wiring board (7) and the lead pitch of the coil device are accurate. Since it is necessary to match, not only is it difficult to manage the lead pitch, but both lead parts (52) (52) of the coil device are connected to the round holes (71) of the printed wiring board (7).
There was a problem that a special jig was required to insert it into the. Also, the extra tip portions (52a) of the pair of lead portions (52) (52)
It was necessary to cut (52a), and there was a problem that the number of steps was large.

On the other hand, as shown in FIG. 19, a coil device (8) in which a coil is wound around a core is embedded in a mold resin (9), and a coil device is provided on both sides of the mold resin (9). A pair of lead terminals (92) (92) electrically connected to the device (8)
There is known a surface-mounting type coil device capable of being surface-mounted on the printed wiring board (4) by protruding. The surface of the printed wiring board (4) has a pair of lands (4
1) (41) is formed, and solder paste is formed on the land (41).
(42) is applied, and the lead terminal (92) is soldered to the printed wiring board (4) by applying solder reflow while the lead terminal (92) is pressed onto the solder paste (42). To be done. According to such a surface mounting type coil device, the process for mounting on the printed wiring board is simplified, but not only the process for resin-molding the coil device (8) is required, but also the pair of leads is used. The terminals (92) and (92) are required, which causes a problem of increasing the number of parts.

Therefore, an object of the present invention is to provide a coil device which has a simple structure and can be surface-mounted on a printed wiring board by a simple process.

[0007]

In a coil device according to the present invention, an annular core (1) is installed on a pedestal (3), and a round shaft wire (having a circular cross section (around) is provided around the core (1). It is equipped with a coil (2) formed by winding 21). Flat lead portions (22) and (22) formed by flattening the cross-sectional shape into a rectangular shape or an elliptical shape are formed at both ends of the round shaft wire (21) that constitutes the coil (2). 22) (22) extends from the front surface side of the pedestal (3) to the back surface side, and further bends in the easy bending direction to form the pedestal.
It extends along the back surface of (3), and its tip (23) (23) is the pedestal
The printed wiring board is locked by (3) and has both flat lead portions (22) and (22) extending along the back surface of the pedestal (3).
Joining surfaces (24) and (24) to be joined are formed on the surface of (4). The flat lead portion (22) of the coil (2) can be formed by pressing the end of the conductor wire (21) having a circular cross section.

According to the above surface mount type coil device of the present invention, the pair of flat lead portions (22) and (22) are formed by pressing the round shaft conductor (21) itself of the coil (2). The flat lead portion (22) extends along the back surface of the pedestal (3) to form a joint surface (24) to be joined to the front surface of the printed wiring board (4). There is no need for a lead terminal as a separate component unlike the mountable coil device, which enables surface mounting without increasing the number of components or the number of manufacturing steps. Further, since the flat lead portion (22) of the coil (2) is bent in the easy bending direction and engages with the pedestal (3), it is not only easy to bend the flat lead portion (22). Without, the joint surface (24) that extends to the back of the pedestal (3)
The area is increased, and reliable soldering is realized.
Furthermore, since both flat lead portions (22) (22) of the coil (2) wound around the core (1) are locked to the pedestal (3) in a tensioned state, the flat lead portions (22) The core (1) is pedestal by (22)
(3) It will be tightly bound on the top, and as a result,
High structural strength can be obtained for the coil device as a whole. Therefore, it is not necessary to fix the pedestal (3) to the core (1) by adhesion or the like.

In a concrete structure, a pair of square holes (31) and (31) are formed in the pedestal (3), and each flat lead portion of the coil (2) is formed.
(22) penetrates the square hole (31) and extends to the back surface side of the pedestal (3). Here, a pair of notches (32) (32) are formed on the outer peripheral end surface of the pedestal (3) to vertically penetrate the pedestal (3), and
Each flat lead portion (22) of (2) extends horizontally on the back surface of the pedestal (3) toward the notch (32) and then vertically penetrates along the wall surface of the notch (32). On the front side of the pedestal (3),
The tip portion (23) is folded back along the surface of the pedestal (3) to be locked to the pedestal (3). Or the pedestal
A pair of notches (36) and (36) are formed on the outer peripheral end surface of (3) so as to penetrate obliquely from the back surface to the front surface of the pedestal (3), and each flat lead portion (22) of the coil (2) is formed. ), By horizontally extending the back surface of the pedestal (3) toward the notch (36), the tip (23) is folded back obliquely along the wall surface of the notch (36), It is locked to the pedestal (3).

In another specific structure, a pair of notches (35) (35) are provided in the outer peripheral end surface of the pedestal (3) to form a recess, and the coil (2) is formed.
Each flat lead part (22) of the pedestal penetrates the notch (35).
It extends to the back side of (3). Here, the pedestal (3) is provided with a central hole (34) having a vertical inner wall, and each flat lead portion (22) of the coil (2) has the back surface of the pedestal (3) at the central hole (34).
After extending horizontally toward the center hole (34), it penetrates in the vertical direction along the inner wall of the central hole (34) and extends toward the surface side of the pedestal (3), and its tip (23) extends along the surface of the pedestal (3). By being folded back, it is locked to the pedestal (3). Alternatively, the pedestal (3) is provided with a central hole (34) having an inclined inner wall, and the coil
Each flat lead portion (22) of (2) extends horizontally from the back surface of the pedestal (3) toward the central hole (34), and then the tip portion (23) of the flat lead portion (22) contacts the inner wall of the central hole (34). It is locked to the pedestal (3) by being folded back in an oblique direction.

[0011]

The coil device according to the present invention has a simple structure and can be surface-mounted on a printed wiring board by a simple process.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. In the coil device according to the present invention, as shown in FIG. 1, an annular core (1) is installed on the surface of a disc-shaped pedestal (3) made of phenol resin, and the core (1) is surrounded by A coil (2) formed by winding a round shaft conductor (21) having a circular cross section is attached to the core to form a core.
(1) is constructed by covering the surface of a core piece (11) made of a magnetic material such as a silicon steel plate with an insulating layer (12). The core piece (1
In 1), a magnetic gap portion (not shown) is formed according to the purpose of the coil device.

Both ends of the round shaft wire (21) constituting the coil (2) project in the axial direction of the core (1) at positions on the diameter line of the core (1), and press working is applied to the both ends. By applying it, the flat lead portion having a flat cross section as shown in FIG.
(22) is formed. The cross-sectional shape of each flat lead portion (22) of the coil (2) is a rectangle in which the length of the core (1) in the radial direction is short and the length of the core (1) in the radial direction is long.
On the other hand, as shown in FIG. 6, the pedestal (3) is provided with a pair of square holes (31) (31) having a minor axis extending in the radial direction of the coil (2) and the outer peripheral end surface of the pedestal (3). A pair of notches (32) (3) that vertically penetrate the pedestal (3) are provided on the outside of the square holes (31) (31).
2) has been opened.

Each flat lead portion (22) of the coil (2) is shown in FIG.
As shown in, the square hole (31) of the pedestal (3) is vertically penetrated from the front side to the back side of the pedestal (3), and the notch (32) is formed on the back side of the pedestal (3).
After bending to the side and extending horizontally along the back of the pedestal (3),
Furthermore, it extends vertically upward along the wall surface of the notch (32), and its tip (23) is folded back along the surface of the pedestal (3).
As a result, the tip portion (23) of the flat lead portion (22) is fixed to the pedestal (3).
Is locked to.

3 to 10 show the manufacturing process of the surface mount type coil device of the present invention. As shown in FIG. 3, a round shaft wire (21) is wound around the core (1) to form a coil.
(2) is formed, and both ends (20) and (20) of the round shaft wire (21) are projected in the same direction. Next, after removing the insulating coating on both ends (20) (20) of the coil (2), the both ends (20) (20) are flattened by pressing as shown in FIG. As shown in FIG. 4, a pair of flat lead portions (22), (22) are formed. Here, each flat lead portion (22) is formed in a rectangular cross section having a minor axis in the radial direction of the core (1). The surface of each flat lead portion (22) of the coil (2) is subjected to solder plating if necessary. As a result, soldering in the mounting process described later becomes more reliable.

On the other hand, a pedestal (3) shown in FIG. 6 is prepared. The pedestal (3) has a pair of square holes (31) (31) and a notch (3
2) (32) has been opened. Here, the square hole (31) is formed in a rectangular shape slightly larger than the cross-sectional shape of the flat lead portion (22) of the coil as shown in FIG. The notch (32) has a square hole.
It will be opened in the same width as (31). On the back surface of the pedestal (3), as shown in FIG. 8, a groove (33) connecting the square hole (31) and the notch (32) to each other.
Is recessed. The groove (33) is a flat lead portion of the coil (2).
The width is the same as or slightly larger than the width of (22) and the depth is the same as or slightly larger than the thickness of the flat lead portion (22).

As shown in FIG. 9, a pair of square holes (31) of the pedestal (3)
The pair of flat lead portions (22) and (22) of the coil (2) is inserted into (31), and the core (1) is placed on the pedestal (3). Then, Figure 1
As shown in 0 (a), both flat lead portions (22) (22) of the coil (2)
Bend along the groove (33) (33) of the pedestal (3),
As shown in (b), the pedestal (3) is bent along the wall surfaces of the notches (32) and (32), and finally the tips (23) and (23) of the pedestal (3) are bent as shown in FIG. ) Fold along the surface. In this process, the flat lead portion (22) of the coil (2) is connected to the groove (3
3) and the notch (32) are fitted for positioning, and the position is stable thereafter. As a result, the pair of flat lead portions (22) (22) of the coil (2) are wound around the ends of the pedestal (3) in a tensioned state, whereby the core (1) is pedestal (3).
It will be firmly tied to the top, the core (1) and the pedestal
Relative movement during (3) is restricted.

11 and 12 show a mounting process of the surface mount type coil device of the present invention. As shown in FIG. 11, a pair of joint surfaces (24) and (24) are formed by the flat lead portions (22) and (22) of the coil (2) extending along the back surface of the pedestal (3). On the (4), a pair of lands (41) (41) are provided corresponding to the pair of joint surfaces (24) (24).
Are formed at predetermined intervals, and the solder paste (42) is applied on the lands (41). As shown in FIG.
Both joint surfaces (24) and (24) of the coil (2) wound around the core (1) are pressed against the solder paste on the printed wiring board (4), and solder reflow treatment is performed in this state. As a result, the coil
Both joint surfaces (24) and (24) of (2) are soldered to the lands (41) and (41) of the printed wiring board (4).

According to the above surface mount type coil device, the round shaft conductor (21) itself of the coil (2) is pressed to form a pair of flat lead portions (22) and (22). Department (2
Since the joint surface (24) is formed by 2), it is not necessary to connect a lead terminal as a separate component as in the conventional surface mount coil device, and this does not increase the number of components or the number of manufacturing steps. , Surface mounting becomes possible. or,
Since the flat lead portion (22) of the coil (2) is bent around the end of the pedestal (3) by bending it in the direction of thin wall thickness, that is, in the direction of easy bending, bending work of the flat lead portion (22) can be performed. Not only is it easy, but the area of the joint surface (24) extending to the back surface of the pedestal (3) is increased, and reliable soldering is realized. Furthermore, the core (1) is composed of both flat lead portions (22) (2) of the coil (2).
Since it is firmly bound to the pedestal (3) by 2), a high structural strength can be obtained as a whole of the coil device. Therefore, it is not necessary to fix the pedestal (3) to the core (1) by adhesion or the like.

FIG. 13 shows another structural example of the surface mount type coil device according to the present invention. Here, the pedestal (3) is
It is formed in a circular shape having an outer diameter slightly larger than the outer diameter of the core (1), and a pair of notches (35) (35) are formed on the outer peripheral end surface of the pedestal (3).
Is recessed. Further, the pedestal (3) is provided with a central hole (34) having a vertical inner peripheral wall. Each flat lead portion (22) of the coil (2) extends to the back surface side of the pedestal (3) along the wall surface of the notch (35) of the pedestal (3), and inside the back surface of the pedestal (3). It bends in the direction and extends horizontally along the groove recessed in the back surface of the pedestal (3), and then bends vertically upward along the inner wall of the central hole (34), and its tip (23) is It is locked to the pedestal (3) by being folded back along the surface of the pedestal (3).
Also in the coil device, the joint surface (24) is formed by the flat lead portion (22) of the coil (2) extending along the back surface of the pedestal (3).

The tip portion (2) of the flat lead portion (22) of the coil (2)
As a structure for locking 3) to the pedestal (3), in the coil device shown in FIG. 1, a notch (32) having a wall surface perpendicular to the outer peripheral end surface of the pedestal (3) is opened as shown in FIG. 14 (a). However, the structure is not limited to the structure in which the tip portion (23) of the flat lead portion (22) is folded back into a U-shape and locked, and as shown in FIG. Open the notch (36) and insert the flat lead (2
It is also possible to adopt a structure in which the tip portion (23) of 2) is folded back into a V shape and locked. Further, in the coil device shown in FIG. 13, a central hole (34) having a vertical inner peripheral wall is opened as shown in FIG. 15 (a), and the tip portion (23) of the flat lead portion (22) is U-shaped.
The structure is not limited to the structure in which it is folded back into a letter shape and locked, but a central hole (34) having an inclined inner peripheral wall is opened as shown in FIG. It is also possible to employ a structure in which the structure is folded back and locked.

The coil device according to the present invention described above is shown in FIG.
~ Having a simple structure equivalent to that of the conventional non-surface mounting type coil device shown in Fig. 18 and having a simpler structure than the conventional surface mounting type coil device shown in Fig. 19, a printed wiring board It can be surface mounted.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a surface mount coil device according to the present invention.

FIG. 2 is an enlarged perspective view showing a state in which a flat lead portion of a coil is wound around an end portion of a pedestal.

FIG. 3 is a perspective view showing a state in which a round shaft wire is wound around a core.

FIG. 4 is a perspective view showing a state in which flat lead portions are formed on both ends of the coil.

FIG. 5 is a process diagram of press working a round shaft wire.

FIG. 6 is an exploded perspective view of a core around which a coil is wound and a pedestal.

FIG. 7 is an enlarged perspective view showing a square hole and a notch formed in a pedestal.

FIG. 8 is a partially cutaway front view showing a state before the core around which the coil is wound is mounted on the pedestal.

FIG. 9 is a partially cutaway front view showing a state in which a core around which a coil is wound is mounted on a pedestal.

FIG. 10 is a series of partially cutaway front views showing the step of winding the flat lead portion of the coil around the end portion of the pedestal.

FIG. 11 is a partially cutaway front view showing a state before the coil device according to the present invention is mounted on a printed wiring board.

FIG. 12 is a partially cutaway front view showing a state in which the coil device according to the present invention is mounted on a printed wiring board.

FIG. 13 is a partially cutaway front view showing another embodiment of the coil device according to the present invention.

FIG. 14 is an enlarged cross-sectional view showing a structure in which the tip end of the flat lead portion of the coil is locked to the outer peripheral portion of the pedestal.

FIG. 15 is an enlarged cross-sectional view showing a structure in which the tip of the flat lead portion of the coil is locked to the inner peripheral portion of the pedestal.

FIG. 16 is a perspective view of a conventional coil device.

FIG. 17 is a partially cutaway front view showing a state before the coil device is mounted on a printed wiring board.

FIG. 18 is a series of partially cutaway front views showing a process of mounting the coil device on a printed wiring board.

FIG. 19 is a partially cutaway front view showing a state before the conventional surface mount coil device is mounted on a printed wiring board.

[Explanation of symbols]

(1) Core (11) Core piece (12) Insulation layer (2) Coil (21) Round shaft conductor (22) Flat lead (23) Tip (24) Joining surface (3) Pedestal (31) Square hole (32) Notch (33) Groove (34) Central hole (35) Notch (36) Notch (4) Printed wiring board (41) Land (42) Solder paste

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01F 15/10 J

Claims (8)

[Claims] 1. An annular core (1) is installed on a pedestal (3), and a coil (2) formed by winding a conductor wire (21) having a circular cross section is mounted around the core (1). In the coil device,
Flat lead portions (22) and (22) each having a flattened cross-sectional shape are formed at both ends of the lead wire (21) that constitutes the coil (2). Both flat lead portions (22) and (22) are pedestal. (3) extends from the front surface side to the back surface side, further bends in the easy bending direction and extends along the back surface of the pedestal (3), and its tip portions (23) (23) are locked to the pedestal (3). Cages, both flat lead portions extending along the back surface of the pedestal (3)
(22) The surface mount type coil device characterized in that the joint surfaces (24) and (24) to be joined are formed on the surface of the printed wiring board by (22). 2. The surface mount type coil device according to claim 1, wherein the flat lead portion (22) of the coil (2) is formed by pressing an end portion of a conductor wire (21) having a circular cross section. 3. The pedestal (3) is provided with a pair of square holes (31) (31), and each flat lead portion (22) of the coil (2) penetrates through the square hole (31) to form a pedestal (31). The surface mount type coil device according to claim 1 or 2, which extends to the back surface side of 3). 4. A pair of cutouts (32) (32) vertically penetrating the pedestal (3) is provided on an outer peripheral end surface of the pedestal (3), and a coil is formed.
Each flat lead portion (22) of (2) extends horizontally on the back surface of the pedestal (3) toward the notch (32) and then vertically penetrates along the wall surface of the notch (32). On the front side of the pedestal (3),
The surface mount type coil device according to claim 3, wherein the tip portion (23) is folded back along the surface of the pedestal (3) to be locked to the pedestal (3). 5. A pair of cutouts are formed in the outer peripheral end surface of the pedestal (3) so as to extend obliquely from the back surface to the front surface of the pedestal (3).
(36) (36) is opened and each flat lead part (22) of the coil (2)
After the back surface of the pedestal (3) is extended horizontally toward the notch (36), the tip (23) is folded back along the wall surface of the notch (36), so that the pedestal (3) The surface mount coil device according to claim 3, wherein the surface mount coil device is locked to (3). 6. A pair of notches (3
5) (35) is recessed and each flat lead part (22) of the coil (2)
The surface mount type coil device according to claim 1 or 2, wherein is extended to the back surface side of the pedestal (3) through the notch (35). 7. The pedestal (3) has a central hole having a vertical inner wall.
(34) is opened, and each flat lead portion (22) of the coil (2) is
After the back surface of the pedestal (3) horizontally extends toward the central hole (34), it vertically penetrates along the inner wall of the central hole (34) and extends to the front surface side of the pedestal (3), and the tip thereof. The surface-mounted coil device according to claim 6, wherein the portion (23) is folded back along the surface of the pedestal (3) to be locked to the pedestal (3). 8. The pedestal (3) is provided with a central hole (34) having an inclined inner wall, and each flat lead portion (22) of the coil (2).
After the back surface of the pedestal (3) extends horizontally toward the central hole (34), its tip (23) is folded back along the inner wall of the central hole (34) in an oblique direction, so that The surface mount type coil device according to claim 6, which is locked to (3).