JP2500987Y2 - Thin transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a thin transformer that contributes to downsizing and thinning of the entire apparatus.

[Prior Art] Conventionally, a transformer is mounted on a circuit board or the like. FIG. 7 is an exploded perspective view showing a conventional example of such a transformer. This conventional transformer is composed of a pair of E-shaped ferrite magnetic cores 101, 101 and a bobbin 102 around which a winding is wound. A pin is formed by winding the bobbin 102 and forming the end of the winding on the bobbin 102. After connecting to the terminal 103, the pair of ferrite magnetic cores 101, 101 was inserted from above and below the bobbin 102, butted and fixed with tape. Below the bobbin 102, each pin terminal 103
Is provided with a pin terminal 104 for connecting to a circuit board,
When mounting this transformer on a circuit board (not shown), etc., the pin terminal 104 is inserted into the through hole of the circuit board to make electrical connection with other parts, and at the same time, mount the transformer on the circuit board. It was fixed to.

[Problems to be Solved by the Invention] However, since it is difficult to reduce the thickness of the transformer according to the above-mentioned conventional technique as described below, when mounted on a circuit board or the like, the height of the transformer is different. It becomes higher than the electronic parts of the above, and an unnecessary space is created above the circuit board etc., which hinders the miniaturization and thinning of the entire device, as well as the winding and the entire transformer. The problem is that the bobbin 102 having a complicated shape having the pin terminal 104 is required for fixing.

That is, in the conventional transformer, from the viewpoint of high-density mounting, the ferrite magnetic core was designed so that the shape of the transformer configured by combining the ferrite magnetic core 101, the bobbin 102, and the winding thereof is close to a cube. Therefore, the height of the ferrite core 101 in the above is about twice the cube root of the electric power transmitted by the transformer, and when the electric power transmitted increases, the height of the ferrite magnetic core increases, resulting in a smaller transformer. It was an obstacle to thinning.

Further, the pin terminals 103, 104 are provided as means for connecting the winding to the bobbin 102 for winding the coil, connecting the winding to a fixed substrate or the like, and fixing the entire transformer.
The bobbin 102 becomes complicated because it is necessary to provide the above. For example, even if the pin terminals 103 and 104 are formed on different members, the assembly is complicated and the number of parts is inevitably increased.

Further, it is mentioned that it is difficult to wind the winding wire in a thin shape, which is one of obstacles to downsizing and thinning the transformer. Therefore, for example, it is conceivable to use a printed coil as proposed in Japanese Utility Model Publication No. 59-15459 to thin the coil constituting the transformer. However, most of the conventionally proposed print coils have a conductor pattern with a thickness of several tens to 100 μm formed on the substrate. In order to pass a relatively large current through the coil, the printed coil is formed on the substrate. It is necessary to stack many printed coils and connect them in parallel. For this reason, the occupancy of the substrate portion other than the conductor pattern through which the current directly flows increases, so the space factor deteriorates, and it is unsuitable as a coil of a transformer that allows a relatively large current to flow. Further, since it is necessary to connect a large number of laminated print coils in parallel, it is expected that the reliability decreases as the number of laminated layers increases.

The present invention was created in view of the above, and is suitable for applications with a relatively large current capacity, and when mounted on a circuit board or the like, the height of other mounted components should be the same for the entire circuit. An object of the present invention is to provide a thin transformer which can save unnecessary space, contribute to downsizing and thinning of the entire apparatus, and can be fixed to a circuit board or the like without increasing the number of parts. .

[Means for Solving the Problems] A thin transformer according to the present invention for achieving the above object has a coil formed by stacking a plurality of flat coils formed by processing a conductive plate, and the above coil. A pair of flat ferrite cores sandwiched between the flat coil and the flat coil, and the flat coil guides the input / output end in one direction and a part of the conductive plate in the opposite direction to the input / output end. It is characterized in that a part of the conductive plate is fixed to a surface to be mounted to serve as fixing means for the entire transformer.

[Operation] The present invention is configured such that flat coils formed by processing flat conductors are laminated to form a coil so that the coil can be made thin and a large current can flow, and a bobbin is used for assembling the coil. Is unnecessary. Further, as a means for fixing the entire transformer to the mounting target, by using the input / output end of the flat coil and a part of the conductor led out in the opposite direction of the input / output end also as the connection to the mounting target, No special fixing member is required.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.
In the structure of the transformer of the present embodiment, 1 is one ferrite core divided into two, 2 is the other ferrite core divided into two, and 2 are flat coils formed by processing a conductive plate as described later. It is a coil that is insulated and is formed by laminating a plurality of sheets.

Each of the ferrite cores 1 and 2 is vertically symmetrically divided into two in an E shape when viewed from the lateral direction, and is divided into a central portion 1a and 2a of the inner leg which is inserted into a through hole 3a provided in the central portion of the coil 3. Outer peripheral portions 1b, 2 composed of a flat plate-like portion that covers the outer periphery of the coil 3 and outer legs
with b and. FIG. 2 is a plan view of the ferrite core 2. As also shown in this figure, the outer peripheral portion 2b (1b is the same) covering the outer periphery of the coil 3 is formed wider and flatter than the central portion 2a (1a). Each ferrite core 1 and 2 is
The central portions 1a and 2a are inserted into the through holes 3a of the coil 3, and the coil 3 is sandwiched and fixed by, for example, tape.

FIG. 3 is a plan view showing one structural example of the flat coil which constitutes the coil 3. The flat coil 31 of this configuration example is
Process the conductive plate by punching or etching,
Two spiral three-turn coils 31a and 31b are formed and attached through an insulating film 31d having a hole 31c to be a through hole to form a six-turn coil. The coils 31a and 31b are arranged so that the front and back of the pattern of the coil portion are opposite to each other so that the current circulation direction is the same,
The inner peripheral ends 31e and 31f are electrically connected, and the outer peripheral ends are projected and led out in the same direction to form input / output terminals 31g and 31h.
Further, in the coil 31a, two fixing protrusions 31i, 31j, which lead out a part of the pattern of the conductive plate, are projected in the direction opposite to the lead-out direction of the input / output terminals 31g, 31h. of course,
One of the two fixing protrusions 31i and 31j may be provided on the coil 31b side.

FIG. 4 is a plan view showing another configuration example of the flat coil that constitutes the coil 3 described above. Flat coil 32 of this configuration example
Is formed by stamping one conductive plate
The turn coil is provided with input / output terminals 32a and 32b which are projected in one direction and led out. In addition, in the flat coil 32, one fixing projection in which a part of the pattern of the conductive plate is led out in the direction opposite to the lead-out direction of the input / output terminals 32a, 32b
Project 32c.

FIG. 5 is a plan view of this embodiment, and FIG. 6 is a side view of this embodiment. In both figures, 4 is a tape for fixing the pair of upper and lower ferrite magnetic cores 1 and 2, whereby the coil 3 sandwiched between the ferrite magnetic cores is fixed. Further, 5 is a circuit board to be mounted. The coil 3 is
The flat coil 31 shown in FIG. 3 and the flat coil 32 shown in FIG. Each flat coil 3
The input / output terminals 31g, 31h, 32a, 32b and fixing protrusions 31i, 31j and 32c derived from 1, 32 are bent toward the mounting surface of the circuit board 5 and reach the mounting surface. Further, the connection ends 31k, 31, 32d, 32e and the fixed ends 31m, 31n, 32f are formed by being bent in parallel to the mounting surface. The transformer of the present embodiment is fixed to the circuit board 4 by connecting the connecting ends 31k, 31, 32d, 32e to the circuit by soldering and fixing the fixed ends 31m, 31n, 31f by soldering. It

 The operation of the embodiment configured as described above will be described.

In the present embodiment, the flat conductor is processed to form the coil 3
Since the flat coils 31 and 32 constituting the above are formed, a relatively large current can be passed and the coil 3 can be formed thin. On the other hand, ferrite cores 1, 2
The outer peripheral portions 1b and 2b covering the outer periphery of the coil 3 can be formed to be wide and flat according to the shape of the coil 3, so that it is thin and the cross-sectional area of the magnetic circuit is ensured to improve the performance of the transformer. Can be maintained. As described above, in this embodiment, the entire transformer is thinned by thinning the coil and the ferrite core. As described above, when the transformer is made thin, the heat radiation area can be made larger than that of the same transformer having a high height, and the temperature rise can be suppressed to a low level. Further, since the flat plate-like conductor electrodes forming the flat coil 3 have strong rigidity in the plane direction, they can be firmly fixed, and can be fixed on the circuit board 5 in both directions of the transformer. Therefore, it can be firmly fixed in the vertical direction. Moreover, this fixing means does not increase the mounting height of the transformer. If the transformer is mounted on the circuit board 5 by such a fixing means by an appropriate means, generally, the height of the electronic components other than the transformer can be selected to be low, so that the unnecessary space above the circuit board 5 can be greatly reduced. It is also possible to reduce the height or to make the height equal to that of other electronic parts so as to eliminate the unnecessary space.

In the above embodiment, the ferrite core can be formed in any shape and can be divided in two, and the shape can be EI or F when viewed from the side. As described above, the present invention can be applied in various ways in accordance with the gist thereof and can take various embodiments.

[Effect of the Invention] As is clear from the above description, the thin transformer of the present invention can be used for a large current and can be assembled without using a bobbin or a special mounting member. In addition, when mounting on a mounting target such as a circuit board, the mounting height is low, and it is possible to securely fix.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention, and FIG.
FIG. 4 is a plan view of the ferrite core of the above embodiment, FIG. 3 is a plan view showing one configuration example of the flat coil of the above embodiment, and FIG. 4 is a plan view showing another configuration example of the flat coil of the above embodiment. ,
FIG. 5 is a plan view showing the above embodiment, FIG. 6 is a side view of the above embodiment, and FIG. 7 is an exploded perspective view showing a conventional example. 1,2 …… Ferrite core, 1a, 2a …… Center part, 1b, 2b…
... outer peripheral part, 3 ... coil, 3a ... through hole, 31 ... flat coil, 32 ... flat coil, 31g, 31h ... input / output terminal, 3
1i, 31j …… Protrusions for fixing, 32a, 32b …… Input / output terminals, 32c…
… Protrusions for fixing, 4 …… tape, 5 …… circuit board.

Claims (1)

(57) [Scope of utility model registration request] 1. A coil having a plurality of flat coils laminated by processing a conductive plate, and a pair of flat ferrite cores sandwiching the coil, wherein the flat coil has input and output ends. It is led out in one direction and part of the conductive plate is led out in a direction opposite to the one direction, and the input / output end and a part of the conductive plate are fixed to a mounting target surface to form a fixing means for the entire transformer. A thin transformer characterized in that.