JPH07263238A - Inductance element - Google Patents

Abstract

PURPOSE:To provide an inductance element which can deal with automatic mounting while reducing the size by contriving the case structure for securing a magnetic core to be mounted on a bobbin with a terminal while abutting each other without requiring any clamp. CONSTITUTION:The inductance element comprises a bobbin 1 with a terminal applied with a winding, a plurality of magnetic cores 20A, 20B loaded to the bobbin 1, and a case 30 having a protrusion 31 for urging the magnetic core 20A, 20 in the abutting direction and fitted over the bobbin 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance element in which a magnetic core is attached to a wound bobbin with a terminal, and particularly to a surface-mounting small transformer, a small choke coil or the like which is used in a frequency range of a voice band. Regarding an inductance element.

[0002]

2. Description of the Related Art A conventional small-sized audio transformer of this type has an operating frequency band of several hundreds of Hz to several kHz, and usually has a structure using a plurality of magnetic cores such as ferrite in order to secure a required inductance. is there. Then, when a plurality of magnetic cores such as ferrite are mounted on the wound bobbin with terminals, the magnetic cores are butted against each other and fixed using a tape, a fastening metal fitting or the like.

[0003]

By the way, recently, a small inductance element (transformer, choke coil, etc.) having a surface mounting terminal for surface mounting on a printed circuit board has been demanded. However, in the case of surface mounting on a printed circuit board. Generally, an automatic mounting machine is used. Therefore, it is necessary that the upper surface of the component is a flat surface so that the suction nozzle of the automatic mounting machine can suck the parts.

In the case of a structure in which a magnetic core made of ferrite or the like is simply butted and fixed to a bobbin with a terminal that is simply wound as in the prior art, the upper surface of a small inductance element is usually the bobbin winding portion. Is not exposed and does not form a flat surface, which is not suitable for suction holding of the suction nozzle. Also, it is conceivable that the magnetic core is butt-jointed with the clamps and integrated, and then the case with the flat top surface is covered, but the clamps fit inside the case, so the case outline becomes larger than necessary. I hate it, and not only is it a problem in miniaturization, but there is also the problem of a large number of assembly steps.

Incidentally, the actual proposal of the applicant of the present invention is 3-5790.
No. 3 "Stopper for electronic parts" has the winding part resin-molded and the upper surface is flat, and the stoppers press and tighten a pair of cores together and the positional displacement between the core and the resin-molded winding However, there is a drawback that a stopper, that is, a clamp is required.

[0006] In addition, the utility model proposed by the present applicant is 3-5790.
No. 4 “Surface mounting inductance element” has a winding part molded with resin and the top surface is flat, but it is necessary to fix the pair of cores with an adhesive agent, and the cores are held in close contact during the bonding process. In addition to the necessity, there is a risk that the core will come off if the reliability of adhesion is low.

In view of the above points, the present invention is capable of fixing the magnetic cores mounted on the bobbin with the terminals in a state where they are butted against each other without using a fastening metal or an adhesive, by devising the case structure, and downsizing. It is an object of the present invention to provide an inductance element that is capable of being assembled, is easy to assemble, and is compatible with automatic mounting.

[0008]

In order to achieve the above-mentioned object, an inductance element of the present invention comprises a bobbin with a terminal around which a winding is wound, and a plurality of magnetic cores mounted on the bobbin with the terminal. And a case which has a protrusion for urging the magnetic cores in a direction of abutting each other and is placed on the outside of the bobbin with the terminal.

Further, the bobbin with the terminal has a bobbin side engaging portion at an end of a piece in which the terminal is planted, and the case has a case side engaging portion engaging with the bobbin side engaging portion. It may be.

It is preferable that the protrusions of the case are formed on the inner side surfaces of the case that face each other, and that the projecting height decreases toward the case opening.

The upper surface of the case is preferably flat.

[0012]

In the inductance element of the present invention, since the case has the protrusion inside which urges the magnetic cores in a direction to abut against each other, a separate fastening member or the like for fastening and integrating the magnetic cores is provided. The means provided in the case is unnecessary, it is not necessary to provide an extra space inside the case, and the outer dimensions of the case can be reduced. In addition, the structure can be simplified. Further, by setting the upper surface of the case to be a flat surface, the suction nozzle of the automatic mounting machine can suction and hold it, which is also effective when the surface mounting terminal is used as the terminal of the bobbin with the terminal.

Further, a bobbin side engaging portion is provided at an end portion of the piece in which the terminal of the bobbin with the terminal is planted, and a case side engaging portion engaging with the bobbin side engaging portion is provided in the case. In this case, the case can be reliably locked (fitted) to the bobbin with the terminal. In addition, the case can serve to fix the positional relationship between the bobbin with terminals and the magnetic core.

Further, when the protrusions of the case are formed on the inner side surfaces of the case which face each other and the protrusion height of the protrusion decreases toward the case opening, the case is connected to the terminal. During the process of covering the attached bobbin, both sides of the combined magnetic core are automatically pressed, so that the case can be smoothly mounted.

[0015]

Embodiments of the inductance element according to the present invention will be described below with reference to the drawings.

1 to 9 show an embodiment of an inductance element according to the present invention in which a small transformer is constructed. In these figures, the small transformer is composed of an insulating resin bobbin 1 and a bobbin 2 of the bobbin 1 with terminals.
A plurality of windings W _{1 to} W _n wound around the bobbin 1 with terminals
A pair of magnetic cores 20A, 2 such as ferrite attached to the
0B and an insulating resin case 30 having a rectangular parallelepiped outer shape. The bobbin 1 and the case 30 are heat resistant,
A high-strength thermoplastic liquid crystal polymer resin having thin-wall moldability is preferable.

As shown in FIG. 10, the bobbin 1 with terminals has collars 3 on both sides of the winding body portion 2, and
Piece 4 which is perpendicular to both collars 3 and bent outwards
It has A and 4B. In order to reduce the mounting height and maintain the strength of the winding barrel 2, the wall thickness T1 of the upper and lower portions is set larger than the wall thickness T2 of the horizontal portion as shown in FIG. For example, the thickness T1 is 0.4 mm, the thickness T2 is 0.25 mm, and the ratio of the thicknesses T1 and T2 is 1.3 ≦ (T1 / T2).
It is desirable to be in the range of ≤3.0. When T1 / T2 is less than 1.3, the effect of reducing the mounting height is small, and when T1 / T2 is more than 3.0, there are problems of thin-wall molding of T2 and insufficient strength of the lateral portion. The inside of the winding barrel 2 is the magnetic core 2
It is an inner peripheral hole 13 for inserting 0A and 20B.

Pieces 4A and 4B integrated with each collar 3 are in the same plane, and metal terminal members 5 are planted at equal intervals on each piece 4A and 4B (for example, pieces 4A and 4B are formed at the time of resin molding).
It is integrally molded with the portion 4B. ). The metal terminal member 5 is bent into a substantially U-shape, and the pieces 4A, 4B are
2A, 4B and the binding terminals 6 protruding from the front end surface of the
And a surface-mounting terminal 7 that is bent along the bottom surface of the. Winding lead-out grooves 8 are formed between the surface-mounting terminals 7 on the bottom surfaces of both pieces 4A and 4B.

On the bottom surface of the pieces 4A and 4B, the pieces 4A and 4B are provided at the portions where the surface mounting terminals 7 are bent along the bottom surface.
The stepped surfaces 9A and 9B are formed by slightly reducing the thickness of the stepped surface. However, the stepped surfaces 9A and 9B are left-right asymmetric, and when the bobbin 1 with terminals is viewed from the bottom side as shown in FIG. In addition, the direction of the bobbin 1 with the terminal can be identified.

Further, bobbin side locking portions 10A, 10B, 10C, 10D are provided at a total of four locations on both end surfaces of the pieces 4A, 4B, respectively, and the bobbin side locking portions 10B, 10 are provided.
C and 10D are composed of a locking projection 11 and a locking recess 12 which have the same shape. However, the bobbin side locking portion 10A is composed of a locking convex portion 11A and a locking concave portion 12A which are different in shape from the other bobbin side locking portions 10B, 10C and 10D. This is to determine (position) the directionality with respect to the case 30, and the locking recess 1 rather than the locking recess 12.
2A is formed short. In addition, the locking protrusions 11, 1
1A has a taper surface 13 with a smaller amount of protrusion toward the upper surface of the piece to facilitate mounting of the case 30.

As shown in FIGS. 11 and 12, a magnetic core 20A made of ferrite, a dust core, or a laminate of silicon steel plates or amorphous magnetic alloy thin plates in a predetermined shape,
20B is a modified E-shaped core, and both ends are leg portions 2
The outer shell 21 has a substantially U-shaped outer portion 21, and the chamfered prismatic portion 23 located in the center of the inner portion of the outer shell 21. The prismatic portion 23 is a portion fitted into the inner peripheral hole 13 of the bobbin 1.

The insulating resin case 30 has a rectangular parallelepiped outer shape with a flat upper surface, and core pressing contact projections are formed on the inner side surfaces of the case, which are the back sides of the front and back surfaces of the case and which face each other (face each other). 31 are formed respectively.
The core press-contacting projection 31 has a tapered surface 32 so that the projecting height decreases toward the case opening 40. The facing interval between the core pressure welding projections 31 is set to be slightly smaller than the length dimension of the pair of magnetic cores 20A and 20B attached together.
1 is a magnetic core 20A mounted on the bobbin 1 with terminals,
The elasticity of the case itself can be used to urge the 20B in a direction in which they face each other. Although the hole 37 in the upper part of the case 30 is located above the core pressure welding protrusion 31, this hole 37 is necessary in the molding step for resin molding the core pressure welding protrusion 31. 30 There is no particular function after molding.

Case-side engaging portions 33A, 33B, 33C and 33D which can engage with the bobbin-side engaging portions 10A, 10B, 10C and 10D are provided at four corners of the opening of the case 30. Case side locking portions 33B, 33C, 33
D has the same shape and has a notch groove 34 that engages (fits) with the locking projection 11 on the bobbin side and a locking piece 35 that engages (fits) with the locking recess 12. is doing. The case side locking portion 33A is connected to the other case side locking portions 33B, 33C, 3
It has a shape different from that of 3D, and the locking projection 11 on the bobbin side
Notch groove 34A engaging (fitting) with A and locking recess 12A
And a locking piece 35A that engages (fits) with. This is done to determine (position) the directionality with the bobbin 1 with terminals, and the cutout groove 34A and the locking piece 35A are formed shorter than the cutout groove 34 and the locking piece 35. ing.

Furthermore, 1 as a small transformer for surface mounting
In order to show the position of the number terminal, as shown in FIGS. 3 and 5, the position display convex portion 36 is formed along the front corner of the case 30.

The magnetic core 20 for the bobbin 1 with terminals
Before mounting the A, 20B and the case 30, a plurality of windings W _{1 to} W _n are wound around the winding barrel 2 of the bobbin 1 with terminals.
The lead-out wire (not shown) is led out through the winding lead-out groove 8, entwined with the entanglement terminal 6 and soldered.

The mounting of the magnetic core 20A, 20B and the case 30 with respect to the winding W ₁ with terminals bobbin 1 which has been subjected to to _W-n is performed in the following procedure.

First, as shown in FIGS. 8 and 9, the prismatic portions 23 of the pair of magnetic cores 20A and 20B are inserted into the inner peripheral holes 13 of the bobbin 1 with terminals, and the prismatic portions 23 and the legs 22 are inserted. The magnetic cores 20A and 20B are arranged on the bobbin 1 with terminals so that they face each other. Then, the case 30 is covered over the bobbin 1 with terminals and the magnetic cores 20A and 20B with the opening thereof facing down. Then, the case opening 4 is provided for the bobbin side locking portions 10A, 10B, 10C, 10D located at both ends of the pieces 4A, 4B of the bobbin 1 with terminals.
Case-side locking portions 33A, 33B, 33C, 3 at four corners of 0
Engage 3D and attach case 30 to bobbin 1 with terminals.
Are fitted and integrated. That is, the locking projection 11 on the bobbin side
The notch groove 34 is engaged (fitted) with the locking recess 1 on the bobbin side.
2 is engaged (fitted) with the locking piece 35, and the notch groove 34A of the case-side locking portion 33A is engaged (fitted) with the locking projection 11A of the bobbin-side locking portion 10A having a different shape. Then, the locking piece 35A is engaged (fitted) with the locking recess 12A.

Since the core pressing projection 31 formed on the case 30 has the tapered surface 32, the case 3
When the bobbin 1 with terminals and the magnetic cores 20A and 20B are covered with 0, the tapered surface 32 is pressed against the outer surface of the substantially U-shaped outer shell portion 21 of the magnetic cores 20A and 20B, and can be smoothly moved. Can be executed smoothly.

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

(1) Core press-contacting projections 31 are formed on the inner surfaces of the insulating resin case 30 that face each other (face each other), and the core press-contacting projections 31 are elastic forces of the case itself to form the magnetic core 20A, Since it abuts on the outer surface of 20B, the pair of magnetic cores can be held in abutted state without using a fastening member. For this reason, it is possible to simplify the structure by omitting the tightening fitting, and to reduce the outer dimensions of the case. In addition, the magnetic cores 20A, 2
By using 0B, it is possible to obtain an inductance sufficient for use in the audio frequency band. The protrusion 3
Two (a plurality of) 1 may be provided on each side, and in this case, the pressure contact function of the magnetic core can be further stabilized without increasing the cost.

(2) Pieces 4A, 4B of bobbin 1 with terminals
Bobbin side locking portions 10A, 10B, 10C, 10
D is provided, and the bobbin side locking portions 10A, 10 are provided on the case 30.
Case-side locking portions 33A that engage with B, 10C, and 10D,
Since 33B, 33C and 33D are provided, the case 30 can be easily attached to the bobbin 1 with terminals. At this time,
Since the bobbin 1 is fitted to the case 30 and the magnetic cores 20A and 20B are fixed by pressure contact inside the case 30, the positional relationship between the bobbin 1 and the magnetic cores 20A and 20B is eventually defined by the case 30. it can. Further, the locking projections 11 of the case side locking parts 33A, 33B, 33C, 33D,
Since 11A has the tapered surface 13, the case 30
Can be smoothly mounted on the bobbin 1.

(3) Since the core pressure contact projection 31 has the tapered surface 32 whose projecting height decreases toward the case opening 40, the tapered surface 32 can contact the outer surface of the magnetic core. The pressure contact projection 31 is the magnetic core 20.
The case 30 is smoothly attached to the bobbin 1 with terminals and the magnetic cores 20A, 2 without being caught by the corner portions of the A, 20B.
It can be covered on the outside of 0B. The inner surface of the case 30 without the protrusion 31 can also serve to regulate the positions of the magnetic cores 20A and 20B.

(4) 1 as a small transformer for surface mounting
In order to show the position of the number terminal, as shown in FIGS. 3 and 5, the position display convex portion 36 is formed along the front corner of the case 30, and the position display convex portion 36 is located closest to the position display convex portion 36. The metal terminal member 5 can be specified as the first terminal.

(5) The bobbin side engaging portion 10A has a different shape from the other bobbin side engaging portions 10B, 10C and 10D, and the case side engaging portion 33A and the other case side engaging portions are correspondingly formed. The shape is different from that of 33B, 33C, 33D, and the directivity between the bobbin with terminal 1 and the case 30 can be determined (positioned).

(6) Pieces 4A, 4B of bobbin 1 with terminals
At the bottom surface of the step mounting surface 7, the surface mounting terminal 7 is bent along the bottom surface to slightly reduce the thickness of the pieces 4A and 4B.
A and 9B are formed, but since the shapes of the step surfaces 9A and 9B are asymmetrical, as shown in FIG. 5, when the bobbin 1 with terminals is viewed from the bottom side, the bobbin 1 with terminals is formed.
Can recognize the direction of.

(7) The upper surface of the case 30 is a flat surface,
As a surface-mounting electronic component, it can be suction-held by a suction nozzle of an automatic mounting machine and can be automatically mounted on a printed circuit board.

In the above embodiment, the case where the transformer having a plurality of windings is constructed as the inductance element has been exemplified, but it is also applicable to the case where the choke coil is constructed with one winding. it is obvious.

In the above embodiment, the case where the modified E-shaped cores are used as the paired magnetic cores is exemplified.
It is also possible to use mold cores or a combination of E-shaped cores and flat plate cores, and the shape of the bobbin with terminals can be changed in accordance with the change in shape of the magnetic core.

Although the embodiment of the present invention has been described above, it is obvious to those skilled in the art that the present invention is not limited to this and various modifications and changes can be made within the scope of the claims. Let's do it.

[0040]

As described above, the inductance element of the present invention urges the bobbin with the terminal, the plurality of magnetic cores mounted on the bobbin with the terminal, and the magnetic cores so as to abut each other. Since it is configured to have a case that has a protruding portion inside and is covered on the outside of the bobbin with terminals, the protruding portion can press the magnetic cores against each other by the elastic force of the case itself, The magnetic cores can be held in abutting state without using any tightening metal. For this reason, it is possible to simplify the structure by omitting the tightening fitting, and to reduce the outer dimensions of the case. Further, by using the magnetic core, it is possible to secure sufficient inductance for use in a low frequency region (audio frequency band or the like).

[Brief description of drawings]

FIG. 1 is a left side cross-sectional view showing a case where a small transformer is formed as an embodiment of an inductance element according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a left side view of the same.

FIG. 5 is a bottom view showing a winding portion in section.

FIG. 6 is a right side view of the same.

FIG. 7 is a rear view of the same.

FIG. 8 is an exploded front view of the same.

FIG. 9 is an exploded side view of the same.

FIG. 10 is a plan view of a bobbin with a terminal used in an example.

FIG. 11 is a front view showing a modified E-shaped core as a magnetic core.

FIG. 12 is a plan view of the same.

[Explanation of symbols]

1 bobbin with terminal 2 winding body part 3 collar 4A, 4B piece 5 metal terminal member 6 entanglement terminal 7 surface mounting terminal 8 winding drawing groove 9A, 9B step surface 10A, 10B, 10C, 10D bobbin side locking part 11, 11A Locking convex part 12, 12A Locking concave part 20A, 20B Magnetic core 30 Insulating resin case 31 Core pressure contact protrusion 32 Tapered surface 33A, 33B, 33C, 33D Case side locking part 34, 34A, Notch groove 35, 35A locking piece 36 convex portion for position display W _{1 to} W _n winding

Claims (4)

[Claims] 1. A bobbin with a terminal around which a winding is wound, a plurality of magnetic cores mounted on the bobbin with a terminal, and a protrusion for urging the magnetic cores in a direction to abut each other on the inside. And a case that covers the outside of the bobbin with terminals. 2. The bobbin with a terminal has a bobbin side engaging portion at an end of a piece in which a terminal is implanted, and the case has a case side engaging portion engaging with the bobbin side engaging portion. The inductance element according to claim 1, wherein 3. The inductance element according to claim 1, wherein the protrusions are respectively formed on inner side surfaces of the case that face each other, and the protrusion height decreases toward the case opening. 4. The upper surface of the case is a flat surface.
The inductance element according to 2 or 3.