JP2000091133A - Terminal structure of transformer and forming method of terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a terminal structure of a transformer which features simple working processes, possible price reduction, low DC resistance, and high performance of the transformer, and to obtain a forming method of the terminal of the transformer. SOLUTION: A coil is divided into one or a plurality of flat type wires which are worked by clockwise or counterclockwise rotation in the direction of the plane of the flat type wires. The coil forms at least a primary winding and a secondary winding respectively. The primary and the secondary windings are inserted into a ferrite core 3 successively to form a magnetic circuit. For the flat type wires which are derived from the ferrite core 3, a primary bending 1-1 is conducted at a point of a fixed length in the direction of the lower part of the ferrite core 3, and then a secondary bending 1-2 is conducted at a point which has reached the lower plane of a transformer in a horizontal direction. Consequently, a first terminal 1a is formed by cutting the flat type wires with a fixed length. Likewise, a second terminal 1b is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a terminal structure of a transformer and a method of forming the terminal, and more particularly to a method of forming a high-frequency transformer for a switching power supply.

[0002]

2. Description of the Related Art It is necessary to electrically insulate a primary side and a secondary side with a switching power supply (hereinafter simply referred to as a power supply).
In the case of a so-called insulated power supply, a conversion transformer
The AC voltage obtained on the secondary side must be rectified by interrupting the primary side current.

Conventionally, the following transformers have been used. A thin wire called an enamel wire is wound around a plastic frame called a bobbin corresponding to the primary side and the secondary side, respectively.
A ferrite core is inserted and fixed in a hole formed in the center of the bobbin, and a magnetic circuit is formed to constitute a transformer. The primary coil and the secondary coil are formed, for example, in two pairs to improve the performance of the transformer (it is better to reduce the leakage inductance by bringing the coupling coefficient closer to 1).
It is general to arrange them in the following order: secondary, primary, secondary, and to use the primary and secondary connected in parallel (commonly called sandwich winding).

[0004] A coil block of one turn to several turns is formed on a double-sided through-hole glass epoxy board by copper etching, and these blocks are stacked in several layers with an insulating sheet interposed therebetween, and a primary part is formed at a terminal lead portion. The side and the secondary side are connected to form a winding part. Finally, a ferrite core is inserted and fixed in a hole at the center of the glass epoxy board to form a magnetic circuit, thereby forming a transformer. This type is sandwich wound as in the case of the type.

As an example, in the case of a 10: 3 transformer,
Two blocks of 5 turns are prepared for the primary side, and 10 blocks are connected by connecting them in series, and two blocks of 3 turns are prepared for the secondary side, and used in parallel connection.

[0006]

However, in the above-mentioned conventional transformer, when the thickness of the transformer is reduced to about 5 mm, there are the following problems. In the above type, the area of the wire wound around the bobbin is reduced, the DC resistance of the winding is increased, and the performance of the transformer is deteriorated.

Further, the bobbin mold is very expensive at several million yen, and requires a large initial investment. Furthermore, if the bobbins are not mass-produced, the unit production cost of the bobbins themselves becomes high. With the above type, it is relatively easy to make the transformer thin while maintaining the performance of the transformer. However, in the case of a transformer, the primary and secondary turns are individually made according to the user's circuit, so it is a standard product. Since there are few things and they are made to order, the double-sided through-hole glass epoxy substrate is very expensive because of the small number of products, and therefore the transformer is also expensive.

Further, a mask (for an etching step) for forming a winding pattern on a double-sided through-hole glass epoxy substrate requires a cost of several hundred thousand yen. Furthermore, if a terminal part is newly developed, a mold cost of several million yen will be required. The present invention has been made in view of the above circumstances, and provides a terminal structure of a transformer and a method of forming the terminal, which has a simple operation process, can reduce the cost, has a small DC resistance, and has a good performance of the transformer. With the goal.

[0009]

According to the present invention, in order to achieve the above object, [1] In a terminal structure of a transformer, a flat wire is processed clockwise or counterclockwise in a plane direction of the wire to form one or more wires. At least a primary winding and a secondary winding are respectively formed by a plurality of divided coils, and are sequentially inserted into a ferrite core to form a magnetic circuit, and a rectangular wire derived from the ferrite core is formed. A first bending is performed in the direction of the lower surface of the ferrite core at a predetermined length, and a second bending is performed again in the horizontal direction after reaching the lower surface of the transformer, and cut into a predetermined length. And a second terminal similarly formed.

[2] In the method of forming the terminals of the transformer, the flat wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the coil are divided into one or more parts. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. The second bend is performed in the horizontal direction again after reaching the lower surface of the transformer, cut at a predetermined length to form a terminal, and the terminal is led out to the same side of the transformer in the same manner. In the process of forming the terminal from the coil, the primary bending position of the terminal is selected so that a plurality of sets of terminals are arranged without contact even if they are provided in the same direction.

[3] In the method of forming the terminals of the transformer, the rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. The second bend is made in the horizontal direction again after reaching the lower surface of the transformer, cut at a predetermined length to form a first terminal, and led out to the same side of the transformer in a similar manner. In the process of forming a second terminal from another coil to be formed,
And selecting the primary bending position of the second terminal so that the two sets of terminals overlap except for their horizontal part,
The overlapping portions are fixed to each other.

[4] In the method of forming the terminals of the transformer, the rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. The second bend is made in the horizontal direction again after reaching the lower surface of the transformer, cut at a predetermined length to form a first terminal, and led out to the same side of the transformer in a similar manner. In the process of forming a second terminal from another coil to be formed,
By selecting the bending position of the second terminal and the length of the horizontal portion being the same, by displacing the angle of the lead portion between the two terminals as appropriate, the arrangement is such that they do not contact each other.

[5] In the method of forming the terminals of the transformer, the flat wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. In the process of performing the second bending in the horizontal direction again after reaching the lower surface of the transformer to form a terminal, a recess is formed along the center of the flat wire.

[6] In the method of forming the terminals of the transformer, the flat wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. The second bend is made in the horizontal direction again after reaching the lower surface of the transformer, cut at a predetermined length to form a first terminal, and led out to the same side of the transformer in a similar manner. In the process of forming a second terminal from another coil to be formed, a terminal in which another metal is plated on the flat wire is formed to increase the strength of the flat wire.

[7] In the method of forming the terminals of the transformer, the rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. Is bent, a coil is guided to the bottom of the ferrite core from the through hole provided in the ferrite core, a second bending is performed again in the horizontal direction at the bottom of the ferrite core, and cut at a predetermined length to cut the bottom of the ferrite core. To form a fixed terminal.

[8] In the method of forming the terminals of the transformer, the rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least the primary winding and the secondary winding are formed by one or a plurality of divided coils. Each of the secondary windings is formed and inserted sequentially into the ferrite core to form a magnetic circuit, and a flat wire derived from the ferrite core is placed at a predetermined length toward the lower surface of the ferrite core in a primary direction. When the bottom of the transformer is reached, a second horizontal bend is performed again in the horizontal direction, cut to a predetermined length to form terminals, and a separately prepared quadrangular prism-shaped plastic is used to form a ferrite core coil. The coil is guided to the bottom surface side of the ferrite core through a hole opened in the surface from which the coil is drawn out, and fixed to the square pillar-shaped plastic.

[0017]

[9] In the method of forming a terminal of a transformer, a rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils. Are formed and inserted into the ferrite core sequentially to form a magnetic circuit.The part protruding from the ferrite core part is cut at a predetermined length, and separately prepared metal leads are used. The ferrite core and the coil are fixed to each other with an adhesive and then bent.

[0018]

Embodiments of the present invention will be described below in detail. FIG. 1 is a view showing the structure of a transformer showing an embodiment of the present invention. FIG. 1 (a) is a top view of the transformer, FIG. 1 (b) is a side view of the transformer, and FIG. 2 is a ferrite of the transformer. FIG. 2 is a configuration diagram of a core, and FIG.
2A is a plan view of a ferrite core of the transformer, and FIG.
(B) is a side view of the ferrite core of the transformer.

As shown in these figures, reference numeral 3 denotes a ferrite core, and 4 denotes a ferrite core plate. This portion is the same as a conventional type using a glass epoxy substrate in order to reduce the thickness of the transformer. You are using 1 is 1
The secondary coil, 2 is a secondary coil, 1a is a terminal of the primary coil, and a flat wire drawn from the ferrite core 3 is bent at a predetermined length in the direction of the lower surface of the ferrite core 3 by a first bending.
-1 and a second bend 1-2 is performed in the horizontal direction again when it reaches the lower surface, and cut at a predetermined length.
a, and the second terminal 1b of the coil is formed in the same manner.

In this figure, reference numeral 2a denotes a first terminal of the secondary coil, and 2b denotes a second terminal. in this way,
When the rectangular wire has a relatively large thickness, the coil can have necessary strength as a terminal, and thus can be directly bent and processed into a terminal of a transformer. Here, the wire is generally called a rectangular wire (the wire maker name is a ribbon wire), unlike a copper thin wire having a circular cross section, and is formed by processing a copper wire having a rectangular cross section.

When a wire having a rectangular cross section is processed into a circular shape, the inner portion is compressed and the outer portion is stretched. Conversely, when a wire with a rectangular cross section is passed between rollers with different intervals on the left and right, and the compression ratio on the left and right is changed, the wire becomes a spiral coil with a fixed diameter (hereinafter simply referred to as a coil). ). An example in which a coil formed in this way is used as a choke coil by combining it with a ferrite core material as shown in FIG. 2 has been put to practical use as a choke coil that requires only a single winding. I couldn't make a transformer that required wires.

Hereinafter, this point will be described in detail. At present, the operating frequency of a switching power supply can be easily realized up to around 500 kHz with the advent of MOS FETs. As a result, in a forward-type switching power supply frequently used as a small output power supply, the input DC voltage 120
For V to 50 V, the number of turns of the power transformer is 2 on the primary side.
The number of turns is required to be about 0 to 10 turns and about 5 to 2 turns on the secondary side.

Now, the primary winding has an original thickness of 0.1 mm.
When the flat wire is processed into a 10-turn coil, the thickness of the entire coil can be made 1 mm to 2 mm.
Since the coil has a flat wire having a width of several mm, the coil has a certain degree of strength, and can be used as it is as a terminal portion of the transformer after processing. On the other hand, assuming a 3-turn coil as the secondary coil, for example, the original thickness of 0.3
When a flat wire of 3 mm is processed into a coil of 3 turns,
The overall thickness of the coil can be made 1 to 2 mm. This coil has higher strength than the primary coil, and can be used as it is as a terminal portion of the transformer after processing.

Here, as shown in FIG. 1 and FIG. 2, the primary coil 1 and the secondary coil 2 are inserted into the center cylindrical portion 3a (referred to as a middle leg) of the ferrite core 3, and the ferrite core plate 4 is placed thereon. Then, the transformer is completed by fixing the ferrite core plate 4 to the ferrite core 3 with an adhesive or a tape. In this case, the primary and secondary coils are not sandwiched in one set, so that the leakage inductance is large. Therefore, when used in a forward converter, the loss is large and the performance is not improved. However, if it is used in a flyback converter, It can be used because the leakage inductance can be large. FIG. 3 shows the arrangement of the coils.

In FIG. 3, reference numeral 1 denotes a primary coil,
A is the winding start of the primary coil, 1B is the winding end of the primary coil, 2 is the secondary coil, 2A is the winding start of the secondary coil, 2B is the winding end of the secondary coil, and 5 is the auxiliary coil. 5A is the start of the auxiliary coil winding, and 5B is the end of the auxiliary coil winding. On the other hand, for use in a forward converter, the primary and secondary coils described above are used for each of the two.
A pair may be prepared and inserted into the middle foot 3a in the order of primary, secondary, primary and secondary to form a sandwich structure to reduce leakage inductance. If a coil for generating an auxiliary power supply is required, another coil may be added.

In this case, the primary coil and the secondary coil are in contact with each other, but since the rectangular wire itself is coated with a strong resin, it has a withstand voltage of about 500 V DC even after passing between the rollers. This is not a problem for ordinary applications requiring a withstand voltage of about 200 V DC. After that, the ferrite core plate 4 is placed and temporarily fixed with an adhesive or a tape, and then a varnish treatment or the like is performed to fix the coil portion and the ferrite core portion to each other.

Finally, the insulating coating is removed from each of the two portions at the beginning and end of winding of each coil, solder finishing is performed, and the coil is formed into a predetermined terminal shape. Hereinafter, the method for forming a terminal of a transformer according to the present invention will be described in detail. In the following embodiments, a method of processing a tip portion of a coil into a terminal of a transformer will be described.

FIG. 4 is an explanatory view of a method of forming terminals of a transformer according to a first embodiment of the present invention. When the rectangular wire has a relatively large thickness, the coil can have necessary strength as a terminal, and thus can be directly bent and processed into a terminal of a transformer. As shown in FIG. 4, 1 is a primary coil, 5 is an auxiliary coil, 1a is a terminal at which the primary coil starts to be wound, and a flat wire derived from the ferrite core 3 is ferrite at a predetermined length. The first bend 1-1 is performed in the direction of the lower surface of the core 3, and the second bend 1-in the horizontal direction is performed again when reaching the lower surface.
2 and cut to a predetermined length to form a first terminal 1a, which also has a second terminal 1b formed at the end of winding of the primary coil.

In the auxiliary coil 5, reference numeral 5a denotes a terminal at which the auxiliary coil starts to be wound.
Performs a first bend 5-1 in the direction of the lower surface of the ferrite core 3 at a predetermined length at a predetermined length, and again performs a second bend 5-2 in the horizontal direction at the lower surface. Then, the first terminal 5a is formed by cutting at a predetermined length, and the second terminal 5 similarly formed at the winding end portion of the auxiliary coil is formed.
b.

That is, the coil protruding from the ferrite core 3 is firstly bent toward the lower surface of the transformer at an appropriate length (the horizontal portion is the terminal horizontal portion, and the length from the ferrite core portion is the terminal horizontal length). When the bottom of the transformer is reached, the secondary bend is performed again in the horizontal direction and cut at an appropriate length (the vertical portion is the terminal vertical portion, the length is the terminal vertical length, and the horizontal portion ahead). Is the pad portion, and its length is called the pad length).

Here, when there are a plurality of primary and secondary coils, they must be connected in parallel or in series. The method and the method of forming terminals for the plurality of coils will be described in detail below. For example, as shown in FIG. 4, when there are two primary coils, if the sum of the terminal horizontal length of the first coil and the pad length is selected to be shorter than the terminal horizontal length of the second coil, 2 Even if the coils of the set are provided in the same direction from the ferrite core, they can be arranged without contact.

A plurality of sets of primary coils manufactured as described above are connected by soldering to a pattern formed on a substrate on which a transformer is mounted at a pad portion, and the coils are connected in parallel or in series as necessary depending on the pattern. Connect to In addition, before or after processing of the terminal part, remove the coating of the necessary part,
Make it electrically conductive.

Next, a second embodiment of the present invention will be described. FIG. 5 is an explanatory diagram of a method of forming terminals of a transformer according to a second embodiment of the present invention. As shown in this figure, when there are two sets of primary coils, here primary coils 1 and 6, terminals are formed in the same manner as in the first embodiment. The shape is similar except for the vertical length.
That is, the terminal horizontal length of the coil located on the upper side of the transformer is longer than that of the lower side by the thickness of the ribbon wire, and the terminal vertical length is shorter than that of the lower side by the thickness of the ribbon wire.

When the coils thus formed are fixed to the ferrite core 3 in the same direction, they are overlapped and connected in parallel, as if they were one coil. FIG.
As shown in the figure, these two sets of coils are connected to pad portions (terminals).
By fixing the terminals 1a and 6a, the terminals 1b and 6b, and the terminals between the vertical portions by spot welding or the like, the strength of the entire terminal is increased and the workability is improved. In FIG. 5, 2a and 2b are terminals of the secondary coil.

Next, a third embodiment of the present invention will be described. FIG. 6 is an explanatory view of a method of forming a terminal of a transformer showing a third embodiment of the present invention, and FIG. 7 is a plan view showing a shape of a ferrite core of this embodiment. In these figures, reference numeral 1 denotes a primary coil having terminals 1a and 1b. Reference numeral 2 denotes a secondary coil having terminals 2a and 2b. Reference numeral 7 denotes a third coil whose terminals 7a and 7b
Is configured to be guided in a direction rotated by 90 ° clockwise with respect to the primary coil 1. Further, reference numeral 8 denotes a fourth coil, and its terminals 8a and 8b are configured to be led out in a direction rotated by 90 ° clockwise with respect to the secondary coil 2.

As described above, when the coil is formed of a rectangular wire, it is disadvantageous to reduce the width of some of the coils in order to reduce the thickness of the coil as much as possible and to reduce the DC resistance. is there. For this reason, it is preferable that a plurality of sets of coils have the same shape except for the thickness. Therefore, for example, when there are two sets of primary coils and two sets of secondary coils, they can be arranged so as to be shifted from each other by 90 degrees so that they do not contact each other.

At this time, the ferrite core 9 may be shaped as shown in FIG. That is, the direction in which the terminals of the coil are led out (arrows a to h) is omitted. It should be noted that the deviation of the lead portion of each coil is not limited to 90 degrees, and various angles can be obtained by devising the shape of the ferrite core. Next, a fourth embodiment of the present invention will be described.

FIG. 8 is an explanatory view of a method of forming a terminal of a transformer according to a fourth embodiment of the present invention. FIG. 8 (a) shows a gradual transition from both sides toward the center of a coil 10 (rectangular wire) of the transformer. FIG. 8 (b) is a diagram in which a recess 10A is formed.
In the figure, a V-shaped recess 10B is formed only at the center of the coil (rectangular wire) of the transformer, and flat portions 10C are formed on both sides.

As described above, when the rectangular wire of the coil 10 is relatively thin and the strength is slightly insufficient when processed into a terminal, a method of forming a recess in such a rectangular wire is advantageous. Making use of the fact that forming a dent along the center of the rectangular wire increases bending strength, it is only necessary to form a dent along the center at the same time as bending when processing a rectangular wire into a terminal by die processing. .

Next, a fifth embodiment of the present invention will be described. If the rectangular wire is relatively thin and the strength is slightly insufficient when processed into a terminal, the following method is also advantageous. That is, although not shown, the rectangular wire is plated with a hard metal such as nickel. If the pad at the tip of the terminal is solder-finished, workability is good, and it is effective to use a copper-containing solder having a hard property as the solder and to improve the strength of the flat wire at the same time.

Next, a sixth embodiment of the present invention will be described. 9A and 9B are explanatory diagrams of a method of forming a terminal of a transformer according to a sixth embodiment of the present invention. FIG. 9A is a top perspective view of the transformer, and FIG. FIG. 4 is a cross-sectional view taken along a line A. In these figures, 11 is a ferrite core,
11a is a middle foot, 12 and 13 are through holes, 14 is a ferrite core plate, and 15 and 16 are rectangular wires.

In this embodiment, when the rectangular wires 15 and 16 are very thin and easily deformed, the terminal portion can be formed by utilizing this property. That is, the through-holes 12 and 13 are provided at the bottom of the ferrite core 11 so that the flat wire 1
Terminals 5 and 16 can be formed by guiding the ferrite core 11 to the outside of the ferrite core 11 through the through holes and fixing the ferrite core 11 to the bottom of the ferrite core 11.

Next, a seventh embodiment of the present invention will be described. 10A and 10B are explanatory diagrams of a method of forming a terminal of a transformer according to a seventh embodiment of the present invention. FIG. 10A is a top perspective view of the transformer, and FIG. FIG. 4 is a cross-sectional view taken along a line A. In these figures, 21 is a ferrite core, 21a is its midfoot, 22 is a ferrite core plate, 2
Reference numerals 3 and 24 denote rectangular wires, and 25 denotes a square columnar plastic cover.

Therefore, when the thickness of the coils (rectangular wires) 23 and 24 is very thin and easily deformed, another method is to form a rectangular column-shaped plastic cover body 25 in advance and to mount the coils of the ferrite core 21. The terminals 23a and 24a can be formed by fixing the coil to the drawing surface and guiding and fixing the coil to the bottom surface of the ferrite core from the holes 26 and 27 opened in the drawing surface of the coil.

Next, an eighth embodiment of the present invention will be described. FIG. 11 is an explanatory view of a method of forming terminals of a transformer according to an eighth embodiment of the present invention, and shows a cross section of a main part.
In this figure, 31 is a ferrite core, 32 is a ferrite core plate, 33 is a rectangular wire led out of the ferrite core 31 by a predetermined length, and 34 is a metal lead connected to the rectangular wire 33.

As described above, when the rectangular wire 33 has a small thickness and does not have the required strength as a terminal, it is necessary to connect and fix the separately prepared metal lead 34 and the rectangular wire 33 to simultaneously obtain electrical conduction and strength. There is. First, the winding start portion (winding end portion) 33-1 of the flat wire 33 is cut at an appropriate length. Separately, a metal lead 34 having sufficient strength is prepared. The metal lead 34 may be a lead frame, one of which is connected by a tie bar.

Then, the winding start part 33-1 of the coil and the tip part 34a of the metal lead 34 are connected. Also, although not shown, the winding end of the coil is connected to the tip of another metal lead. As a connection method, any method such as connection by soldering 35, crimping, caulking, and welding may be used. A portion (hereinafter, referred to as a junction portion) 33-1 connecting the metal lead 34 and the coil increases in thickness, so that the thickness of the entire coil increases. When the inner diameter of the core portion in which the coil is housed is larger than the thickness of the coil, the junction is positioned so as to be inside the core.

After that, the coil is inserted into the middle foot of the ferrite core 31, the ferrite core plate 32 is placed, and the ferrite core 31 and the junction 33-1 are fixed to each other with an adhesive. The adhesive may be applied to both the ferrite core portion and the junction portion to be bonded in advance and assembled. Since the adhesive enters between the core portion and the junction portion and is hardened, both the metal leads 34 are firmly fixed to the ferrite core 31 and are electrically insulated from the ferrite core 31. Finally, the metal lead 34 is bent, and an extra portion is cut off to form a transformer terminal 34b.

Next, a ninth embodiment of the present invention will be described. FIG. 12 is an explanatory view of a method of forming terminals of a transformer according to a ninth embodiment of the present invention, showing a cross section of a main part.
In this figure, 41 is a ferrite core, 42 is a ferrite core plate, 43 is a lead portion of a coil (rectangular wire), 44 is a lead end portion of the coil, 45 is a metal lead, 45b is a terminal of a transformer, 46 is an adhesive, Reference numeral 47 denotes soldering, welding, or the like.

As described above, when the inner diameter of the ferrite core in which the coil is housed is smaller than the thickness of the coil, the junction is positioned so as to be outside the ferrite core. Then, the ferrite core and the coil are bonded in the same procedure as described above. After that, the metal lead 45 is bent, and an extra portion is cut off to form a terminal 45 of the transformer.
b is formed. In this case, the junction part having bending strength is not fixed to the core part, so that it is not sufficient as it is. Then, the adhesive 46 is injected into the gap between the core and the junction and fixed.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0052]

As described above, according to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, a plurality of primary, secondary, and other windings are respectively formed by a spiral coil formed by processing a rectangular wire, and each of the above-described windings is provided on the middle foot portion of the ferrite core. After inserting and temporarily fixing the ferrite core plate, varnishing etc. is performed to fix the coil part and the ferrite core part to each other, and the winding start and end of the spiral coil are bent into the prescribed terminal shape Since the transformer is used as the transformer, (a) Unlike the type using a bobbin, an expensive mold is not required for the entire structure of the transformer. In some cases, a mold is required to bend the terminals of the transformer, but it is inexpensive and can be used for other purposes.

(A) Compared with the conventional type using a double-sided through-hole glass epoxy substrate, it is possible to easily cope with a change in the number of coils during the trial production without any cost. (C) Since the main material is only a ferrite core and rectangular wire without using a bobbin or a double-sided through-hole glass epoxy board with a large quantity effect, even if the production quantity is small, the production parts cost does not change and the work process is simple. Therefore, the price can be reduced.

(D) Since a bobbin or a glass epoxy substrate is not used, the cross-sectional area of the copper wire is large, so that the DC resistance is small and the performance of the transformer is good. (2) According to the second aspect of the present invention, the coil protruding from the ferrite core is bent at an appropriate length in the direction of the lower surface of the transformer, and when it reaches the lower surface of the transformer, bent again in the horizontal direction. The length of the horizontal part of each terminal was selected so that even if multiple coils were required and the ferrite cores were placed in the same direction, they would not touch each other. Provided, it is possible to connect them in series or in parallel with a pattern on the substrate, and the performance of the transformer is improved, and the configuration of the transformer including selection of the transformer ratio is facilitated.

(3) According to the third aspect of the present invention, a plurality of sets of coils are bent by the method of (2), and the terminals are overlapped when the coils are positioned in the same direction with respect to the core. Select the length of the horizontal part and the length of the vertical part of the terminal,
Since the pad portions are fixed to each other and the vertical portions of the terminals are fixed by a method such as spot welding, a plurality of coils can be directly connected in parallel, and the strength of the entire terminal is increased, thereby improving workability.

(4) According to the fourth aspect of the present invention, a plurality of sets of coils are bent by the method of (2) and inserted into the middle foot of the ferrite core so that the coils do not come into contact with each other. Since the coil lead-out portions are arranged at an appropriate angle, the transistor having many windings can be easily manufactured. (5) According to the fifth aspect of the present invention, the operation of bending the coil by the method of (2) is performed by die processing, and the depression is formed along the center portion of the flat wire at the same time as the bending. As a result, it is possible to use even objects with a somewhat insufficient strength.

(6) According to the invention of claim 6, after bending the coil by the method of (2), the terminal portion is plated with a hard metal such as nickel, and the pad portion at the terminal tip also contains copper. The use of solder plating enables the formation of terminals by rectangular wires, even if the terminals have somewhat insufficient strength. (7) According to the seventh aspect of the present invention, since the coil is guided to the bottom surface of the ferrite core from the opening provided in the ferrite core and fixed to form a terminal, it is possible to use even a terminal having insufficient strength as a terminal. .

(8) According to the eighth aspect of the present invention, the square-pillar-shaped plastic cover body is formed and fixed to the surface from which the coil of the ferrite core is drawn, and the ferrite core bottom surface side is opened from the hole opened in the coil drawing surface. Since the coil is guided and fixed as a terminal, it is possible to use even a flat wire (coil) with insufficient strength. (9) According to the ninth aspect of the present invention, the flat wire is processed,
After forming the coil, cut at the appropriate length of the winding start and end, and connect the separately prepared metal leads to the respective tips by welding, soldering, or other means,
Since the connection point, the ferrite core and the coil were fixed to each other with an adhesive and then processed to form a terminal, it was possible to use a coil having insufficient strength.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a structure of a transformer according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a ferrite core of a transformer showing an embodiment of the present invention.

FIG. 3 is a diagram showing a state of arrangement of coils showing an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a method of forming a terminal of a transformer according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a method of forming a terminal of a transformer according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a method for forming a terminal of a transformer according to a third embodiment of the present invention.

FIG. 7 is a plan view showing a shape of a ferrite core according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a method of forming a terminal of a transformer according to a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram of a method of forming a terminal of a transformer according to a sixth embodiment of the present invention.

FIG. 10 is an explanatory diagram of a method of forming a terminal of a transformer according to a seventh embodiment of the present invention.

FIG. 11 is an illustration of a method of forming a terminal of a transformer according to an eighth embodiment of the present invention.

FIG. 12 is an explanatory diagram of a method of forming a terminal of a transformer according to a ninth embodiment of the present invention.

[Explanation of symbols]

1, 6 Primary coil 1-1, 5-1 Primary bending 1-2, 5-2 Secondary bending 1a, 2a, 5a, 7a, 8a, 23a First terminal (pad portion) 1b , 2b, 5b, 7b, 8b Second terminal (pad portion) 1A Start of winding of primary coil 1B End of winding of primary coil 2 Secondary coil 2A Start of winding of secondary coil 2B End of winding of secondary coil 3, 9, 11, 21, 31, 41 Ferrite core 3a, 11a, 21a Column portion (middle foot) 4, 14, 22, 32, 42 Ferrite core plate 5 Auxiliary coil 5A Starting winding of auxiliary coil 5B End of winding of auxiliary coil 7 Third coil 8 Fourth coil 10 Coil 10A Flat wire dent 10B V-shaped dent 10C Flat plate portion 12,13 Through hole 15,16,23,24,33 Flat wire 25 Square prism Plastic cover bodies 26 and 27 Open holes 33-1 Junction [Start of winding of rectangular wire 33 (End of winding)] 34,45 Metal lead 34a Tip of metal lead 34b, 45b Terminal of transformer 35 Soldering 43 Coil (rectangular wire) lead-out part 44 Coil lead-out end part 46 Adhesive

Claims (9)

[Claims] 1. A rectangular wire is processed clockwise or counterclockwise in its plane direction, and at least a primary winding and a secondary winding are respectively formed by one or a plurality of divided coils, and a ferrite is formed. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. A second terminal is formed by performing secondary bending in the horizontal direction again at the place where the second terminal is cut to a predetermined length, and a second terminal similarly formed. Transformer terminal structure. 2. A flat wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are respectively formed by one or a plurality of divided coils, and a ferrite is formed. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. In the process of forming a terminal by performing a second bending again in the horizontal direction at a place where it has been cut and cutting it at a predetermined length, and forming a terminal from another coil led out to the same side of the transformer in a similar manner. A method of forming a terminal of a transformer, comprising selecting a primary bending position of the terminal so as to arrange a plurality of sets of terminals without contact even if they are provided in the same direction. 3. A flat wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils, respectively. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. At this point, a second bending is performed again in the horizontal direction, and the first terminal is formed by cutting at a predetermined length, and a second terminal is formed from another coil led out to the same side of the transformer in a similar manner. In the process of forming the terminal,
A transformer characterized in that by selecting a primary bending position of the first and second terminals, two sets of terminals are overlapped except for their horizontal parts, and the gaps between the overlapping parts are fixed. Method of forming terminals. 4. A rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils, respectively. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. At this point, a second bending is performed again in the horizontal direction, and the first terminal is formed by cutting at a predetermined length, and a second terminal is formed from another coil led out to the same side of the transformer in a similar manner. In the process of forming the terminal,
A terminal for a transformer, wherein even if the length of the horizontal portion is the same by selecting the bending position of the first and second terminals, the horizontal portion is not in contact by appropriately shifting the angle of the lead-out portion. Formation method. 5. A rectangular wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils, respectively, and a ferrite is formed. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. Forming a terminal along the center of the rectangular wire in the process of forming a terminal by performing secondary bending in the horizontal direction again at the place where the terminal is formed. 6. A flat wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils, respectively. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. At this point, a second bending is performed again in the horizontal direction, and the first terminal is formed by cutting at a predetermined length, and a second terminal is formed from another coil led out to the same side of the transformer in a similar manner. In the process of forming the terminal,
A method for forming a terminal of a transformer, comprising forming a terminal in which another metal is plated on the rectangular wire in order to increase the strength of the rectangular wire. 7. A flat wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are respectively formed by one or a plurality of divided coils, and a ferrite is formed. The ferrite core is inserted into the core in order to form a magnetic circuit. Guide the coil from the through hole to the bottom of the ferrite core, make a second horizontal bend again at the bottom of the ferrite core, cut it to a predetermined length, and form a terminal fixed at the bottom of the ferrite core. Characteristic method of forming transformer terminals. 8. A flat wire is processed clockwise or counterclockwise in its plane direction, and at least a primary winding and a secondary winding are formed by one or a plurality of divided coils, respectively, and a ferrite is formed. It is inserted into the core in order to form a magnetic circuit, and the flat wire drawn out of the ferrite core is bent at a predetermined length in the direction of the lower surface of the ferrite core to reach the lower surface of the transformer. The second bending is performed in the horizontal direction again at the place where the terminal is formed by cutting it to a predetermined length to form a terminal, and a separately prepared quadrangular prism-shaped plastic is fixed to a surface of the ferrite core from which the coil is drawn, and the coil is drawn. A method for forming a terminal of a transformer, comprising: guiding a coil to a bottom surface of a ferrite core from a hole opened in a surface thereof and fixing the coil to the square column-shaped plastic. 9. A flat wire is processed clockwise or counterclockwise in the plane direction, and at least a primary winding and a secondary winding are respectively formed by one or a plurality of divided coils, and a ferrite is formed. Inserted sequentially into the core, configured to form a magnetic circuit, cut the part protruding from the ferrite core at a predetermined length, connected separately prepared metal leads to each tip, A method for forming a terminal of a transformer, comprising: fixing the connection portion, the ferrite core, and the coil to each other with an adhesive, and then performing bending.