JPH0531213U - Trance - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to improve the structure of the base and to realize the downsizing and thinning of the transformer. [Structure] A core 22 is provided around the coil, and the flexible printed circuit board 2 as a base is provided on the core 22.
Fix 3 In this case, the flexible printed circuit board 2
3, a plurality of conductor patterns which are terminal conductors are formed, an external connection electrode 24 is provided at one end of each conductor pattern, and a wire connection electrode 25 is provided at the other end. Then, the wire connection electrode 25 is configured to be connected to the tip (coil end) of the wire 26 pulled out from the coil.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a transformer, and more particularly, to a small transformer in which terminals are soldered to a printed circuit board or the like for use.

[0002]

[Prior Art]

 8 to 10 are views showing a conventional example, FIG. 8 is a perspective view of a transformer, FIG. 9 is a plan view and a side view of a base, and FIG. 10 is a bottom view of a base.

In the figure, 1 is a base, 1b is a mounting surface, 3 is a coil, 3a is a coil terminal, 4 and 5 are solders, 6 is a printed circuit board, 9 is a recess, 10 is a terminal, 10a is a barbed portion, and 10b. Is a soldering portion, 10c is a bent portion, and 16f is a notch for twisting the coil end.

Conventionally, among transformers, which are soldered to a printed circuit board, a coil wound around a bobbin or a core is soldered to a terminal fixed to the bobbin or the base by a winding machine. It was fixed by soldering to the conductor on the printed circuit board.

In this case, the terminal is fixed to the collar or base of the bobbin by integral molding or the like, the vicinity of the barb is bent from the coil end of the terminal, and the tip of the bent part is made into a conductor on the printed board. Although it was soldered, (1) Since the barbed part of the coil end and the soldered part of the printed circuit board are formed in the same direction on the terminal, the shape of the protruding part from the terminal base etc. becomes complicated. The mounting space for the coil component on the printed circuit board becomes large, and (2) solder horns are formed around the terminals during soldering, and flatness cannot be maintained when mounting on the printed circuit board. There was a flaw.

Therefore, in order to improve the above points, coil components as shown in FIGS. 8 to 10 have been developed. This transformer has an improved terminal structure, which will be described below with reference to the drawings.

The terminal 10 has a substantially L-shaped planar shape, and one end of the terminal 10 is a soldering portion 10b to the printed circuit board 6 and the other end is a barb portion 10a of the coil terminal 3a. The vicinity of the portion 10b is vertically bent (10c) so that an inclined surface is formed so that the soldering portion 10b and the flared portion 10a have different heights.

Then, the terminal 10 is integrally molded on a resin base 1 having a substantially rectangular shape so that the portions other than both ends are buried in the base 1, and the barbed portion 10 a is formed from a side surface of one side of the base 1. In addition to projecting, the soldering portion 10b is projected horizontally from the side adjacent to one side of the base 1, and the soldering surface of the soldering portion 10b (the surface facing the conductor 15 on the print substrate 6) is formed. The base 1 is formed on substantially the same surface as the mounting surface 1b on the printed circuit board 6.

Further, the mounting surface 1b is formed as a surface protruding to the surface of the base 1 facing the printed circuit board 6 so as to support the base of each soldering portion 10b. Then, similarly to the above, the end 3a of the coil is entangled with the entangled portion 10a and soldered (4), and the soldered portion 10b is soldered (5) to the printed circuit board 6.

With this configuration, the protrusion width of the terminal 10 becomes smaller than that in the case where the tang portion 10a and the soldering portion 10b are in the same position. Therefore, the space for mounting the transformer on the printed board is reduced. Further, the transformer can be mounted while maintaining its flatness without tilting with respect to the printed circuit board.

[0011]

[Problems to be solved by the device]

 The conventional device as described above has the following problems. The conventional transformer shown in FIGS. 8 to 10 uses the resin base 1 in which the terminals 10 are integrally molded. The barb portion 10a and the soldering portion 10b of the coil end protruding from the resin base 1 have different heights.

Therefore, the resin base 1 becomes thick and it becomes difficult to downsize the transformer. An object of the present invention is to solve such conventional problems, improve the structure of the base, and realize the miniaturization and thinning of the transformer.

[0013]

[Means for Solving the Problems]

 The present invention has the following configuration to solve the above problems. (1) In a transformer including a coil forming each winding of a transformer, a core forming a magnetic path, and a base having a terminal conductor, a core is provided around the coil and a flexible print is used as the base. Using the substrate, the flexible printed circuit board was fixed to the core.

(2) In the configuration (1), the flexible printed board is provided with a plurality of conductor patterns as terminal conductors, one end of each conductor pattern is provided with an external connection electrode, and the other end is provided with an external connection electrode. A wire connecting electrode was provided, and the coil terminal extracted from the coil was connected to the wire connecting electrode.

(3) In the above configuration (2), the external connection electrode and the wire connection electrode are arranged at the ends of the flexible printed circuit board in different directions. (4) In the configuration (3), the external connection terminal is arranged on the side surface of the core by bending a part of the flexible printed board.

[0016]

[Action]

 Since the present invention is configured as described above, it has the following effects. A flexible printed circuit board is used as the base of the transformer, and this flexible printed circuit board is fixed to the core provided around the coil. In this case, since the flexible printed circuit board is extremely thin and light, the transformer can be made thinner and smaller.

Further, the transformer of the present invention can be configured as a surface mount component by disposing the external connection electrode on the side surface of the core. When mounting this transformer on a motherboard, for example, the circuit pattern on the motherboard and the external connection electrodes are soldered. In such a mounted state, the portion protruding from the side surface of the core is extremely thin, so that the mounting space on the motherboard is small.

[0018]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. (Description of First Embodiment) FIGS. 1 to 4 are views showing a first embodiment of the present invention. FIG. 1 is a perspective view of a transformer (complete product), and FIG. 2A is a diagram of a flexible printed circuit board. A plan view, FIG. 3B is a view showing a bent state of the flexible printed circuit board, FIG. 3 is an explanatory diagram of a process of assembling the core and the coil, and FIG. 4 is an explanatory diagram of a process of assembling the core and the flexible printed circuit board. is there.

In the figure, 21 is a transformer, 22 is a core, 22-1 is a first core, 22-2 is a second core, 23 is a flexible printed circuit board, 24 is an external connection electrode, 25 is a wire connection electrode, 26 is a wire, 27 is an adhesive, 28 is a coil, 29 is a coil bobbin, and 30 is a conductor pattern.

FIG. 1 is a perspective view of the transformer according to the first embodiment. In this example, a flexible printed circuit board was used as the base of the transformer and configured as an SMD (surface mount component).

As shown in FIG. 1, the transformer 21 is composed of a core 22, a coil housed in the core 22, and a flexible printed circuit board 23 provided below the core 22.

The core 22 is composed of two cores, which will be described later, and these cores are joined by an adhesive 27. An external connection electrode 24 and a wire connection electrode 25 are provided at the end of the flexible printed circuit board 23 of the base, and the flexible printed circuit board 23 and the core 22 are bonded to each other by an adhesive on the surface opposite to these electrodes. Fixed by.

Then, to the wire connection electrode 25, the end portion (coil end) of the wire 26 extracted from the coil housed in the core 22 is connected by soldering. In this case, the external connection electrode 24 is an electrode to be soldered to a circuit pattern on a motherboard, for example.

Further, the external connection electrode 24 and the wire connection electrode 25 are arranged on different side surfaces (in this example, four electrodes of the same kind are collectively arranged on the same side surface). Hereinafter, the transformer will be described in more detail including the manufacturing process thereof.

The flexible printed circuit board 23, which is the base of the transformer 21, is configured as shown in FIG. As shown in FIG. 2A, the flexible printed board 23 has an outer shape in which four corners are cut off into a rectangular shape from a rectangular sheet.

A plurality of independent conductor patterns 30 (eight patterns in this example) are formed on one surface of the flexible printed circuit board 23, and an external connection electrode 24 is formed at one end thereof. At the same time, the wire connection electrode 25 is formed on the other end.

In this case, each of the external connection electrodes 24 and the wire connection electrodes 25 is arranged in pairs of four and arranged at the ends in different directions. The flexible print substrate 23 thus configured is bent at a position indicated by a dotted line in FIG. 2A to have a shape as shown in FIG. 2B.

At this time, since the core is placed inside the dotted line in the figure, the size of the bottom surface of the core is adjusted so that the external connection electrode 24 and the wire connection electrode 25 are on the outside. In the flexible printed board 23, the conductor pattern 30 other than the electrodes is covered on both sides with an insulator.

The core 22 and the coil are configured as shown in FIG. As shown in the figure, the core 22 is composed of a first core (upper core) 22-1 and a second core (lower core) 22-2, and its cross-sectional shape is substantially a U-shape.

The coil 28 constitutes a winding of the transformer, and is composed of a primary coil PW and a secondary coil SW. Four wires 26 are drawn out from the coil 28, and the ends thereof are connected to the wire connection electrodes 25 of the flexible printed board 23 by soldering. The coil 28 is wound around the coil bobbin 29, for example.

The coil 28 is sandwiched between the first core 22-1 and the second core 22-2 so as to be integrated. In this case, the joint portion between the first core and the second core is , The adhesive 27 is applied in advance, and the first and second cores 22-1 and 22-2 are bonded and fixed.

In this case, if the inner dimension (height) of the core when the first and second cores are joined is set to be slightly smaller than the height of the coil 28, the first and second cores are joined together. Thus, the coil 28 can be housed and fixed therein.

The inner dimension of the core and the height of the coil are set to be substantially the same, an adhesive is applied to the coil 28 or the coil bobbin 29, and the core and the coil are fixed by this adhesive. May be.

The core and coil integrated as described above are bonded to the flexible printed circuit board 23 as shown in FIG. 4 to be a completed product. In this case, an adhesive is applied to a predetermined portion (a part or all of the surface fixed to the core) of the flexible print substrate 23, and the integrated core 23 is placed on the adhesive to bond the two.

By this adhesion, the external connection electrode 24 is fixed to the side surface of the core 22, and the wire connection electrode 25 is fixed to the opening end side of the side surface of the core 22. After that, the ends of the wires 26 are soldered to the wire connecting electrodes 25 to form a transformer as shown in FIG.

(Explanation of Second Embodiment) FIGS. 5 and 6 are views showing a second embodiment, FIG. 5 is a perspective view of a transformer, and FIG. 6 is an explanatory view of an assembling process of the transformer.

In the figure, the same symbols as those in FIGS. 1 to 4 indicate the same components. Reference numeral 31 indicates a core cover. The second embodiment is an example of a transformer similar to that of the first embodiment, except that an adhesive is not used to connect the first and second cores, but the core cover is used.

As shown in the perspective view of FIG. 5, the transformer 21 of the second embodiment includes a core 22, a coil housed in the core 22, and a flexible print substrate provided below the core 22. 23 and a core cover 31 provided outside the core 22.

Further, the flexible printed board 23 is provided with an external connection electrode 24 and a wire connection electrode 25, and the tip of the wire 26 extracted from the coil is soldered and fixed to the wire connection electrode 25. There is.

Hereinafter, the transformer 21 will be described including an assembling process with reference to FIG. The flexible printed board 23 has the same structure as the flexible printed board of the first embodiment shown in FIG. 2 and is manufactured in the same manner.

The core 22 also has the same structure as the core of the first embodiment shown in FIG. 3, and the first core (upper core) 22-1 and the second core (lower core) 22-2. It consists of and. Then, the first and second cores 22-1 and 22-2 are overlapped with each other with a coil constituting a winding of the transformer interposed therebetween.

In this case, as in the first embodiment, the bonding surfaces of the first and second cores 22-1 and 22-2 are directly laminated without applying an adhesive. After that, the stacked core 22 is placed on the flexible printed circuit board 23, and the core cover 31 tightens the core 22 from the outside to integrate them.

Next, the end portion (coil end) of the wire 26 is soldered to the wire connection electrode 25 to form the transformer shown in FIG. In this case, the coil, the core, and the flexible printed board can be fixed to each other without using any adhesive.

However, for example, an adhesive may be applied to a part of the flexible printed circuit board 23, and the flexible printed circuit board 23 and the core 22 may be bonded by this adhesive. By doing so, a stronger fixation becomes possible.

When the transformer thus completed is mounted on, for example, a mother board, the external connection electrode 24 and the circuit pattern on the mother board are soldered.

(Description of Other Embodiments) The embodiments have been described above, but the present invention can also be implemented as follows. (1) As the coil in the first and second embodiments (coil forming the winding of the transformer), a coil as shown in FIG. 7 may be used.

For example, as shown in FIG. 7A, a coil formed by winding a wire in a spiral shape and fixing the wound wire by cement is used as a primary coil and a secondary coil of a transformer, and in between, a coil shown in FIG. You may use the coil which intervened the insulating sheet shown in FIG.

Further, as shown in FIG. 7B, for example, a coil formed by spirally winding a copper foil is used as a primary coil and a secondary coil of a transformer, and an insulating sheet as shown in FIG. 7C is provided between them. You may use the coil which intervened.

(2) In addition to the coil shown in FIG. 7, various coils may be used. (3) The number of external connection electrodes and wire connection electrodes may be set to any number in accordance with the number of lead wires of the coil used. However, some electrodes may not be used.

(4) When the tip of the wire pulled out from the coil is connected to the wire connection electrode, it may be soldered by a means such as spot or ultrasonic wave, or other means may be used. ..

(5) The shape of the core is not limited to the shape of the above embodiment, but may be another shape. (6) The flexible printed circuit board in the portion where the wire connection electrode 25 is provided may not be bonded to the core. In this case, the wire connection electrode 25 may be provided on the core side.

[0052]

[Effect of the device]

 As described above, the present invention has the following effects. (1) Since the flexible printed circuit board is used as the base of the transformer, the transformer can be made thinner, lighter and smaller.

(2) Since the wire connection electrode and the external connection electrode are provided on the flexible printed circuit board and arranged in different directions, the shape of the protruding portion from the side surface of the core can be simplified (as in the conventional example). There is no complicated shape, and the protrusion width can be made extremely small. Therefore, the mounting space for mounting on a motherboard or the like is reduced.

(3) By arranging the external connection electrode on the side surface of the core, the transformer can be used as a surface mount component. Therefore, it can be easily implemented in a small space for mounting on a motherboard or the like.

[Brief description of drawings]

FIG. 1 is a perspective view of a transformer according to a first embodiment of the present invention.

FIG. 2A is a plan view of a flexible printed circuit board, B
FIG. 6 is a diagram showing a bent state of a flexible printed circuit board.

FIG. 3 is an explanatory diagram of a process of assembling the core and the coil.

FIG. 4 is an explanatory diagram of an assembling process of the core and the flexible printed board.

FIG. 5 is a perspective view of a transformer according to a second embodiment of the present invention.

FIG. 6 is an explanatory view of a transformer assembling process in the second embodiment.

FIG. 7 is an explanatory diagram of a coil according to another embodiment.

FIG. 8 is a perspective view of a conventional transformer (a mounting diagram on a printed circuit board).

9A is a plan view of the base, and FIG. 9B is a side view of the base.

FIG. 10 is a bottom view of the base.

[Explanation of symbols]

 21 Transformer 22 Core 22-1 First Core 22-2 Second Core 23 Flexible Printed Circuit Board 24 External Connection Electrode 25 Wire Connection Electrode 26 Wire 27 Adhesive 28 Coil 29 Coil Bobbin 30 Conductor Pattern 31 Core Cover

Claims (4)

[Scope of utility model registration request] 1. A coil (2) forming each winding of a transformer.
8), a core (22) forming a magnetic path, and a base having a terminal conductor. In a transformer, the core (22) is provided around the coil (28), and the base is a flexible printed circuit board. (23)
The flexible printed circuit board (23) using a core (22)
A transformer characterized by being fixed to. 2. The flexible printed circuit board (23)
A plurality of conductor patterns (30) as terminal conductors are provided, an external connection electrode (24) is provided at one end of each conductor pattern (30), and a wire connection electrode (25) is provided at the other end. The transformer according to claim 1, wherein a coil terminal extracted from the coil (28) is connected to the wire connection electrode (25). 3. The flexible printed circuit board (2) is provided with the external connection electrode (24) and the wire connection electrode (25).
The transformer according to claim 2, wherein the transformers are arranged at the ends of the different directions of 3). 4. The flexible printed circuit board (23)
The transformer according to claim 3, wherein the external connection electrode (24) is arranged on a side surface of the core (22) by bending a part of the core.