JPH1012454A - Winding structure of transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the winding structure of a transformer which can reduce power loss due to soldering parts between the conductor part of winding and terminals, conduct effectively the heat generated in the winding, and dissipate the heat. SOLUTION: A thin plate type metal conductor 5a which is turned into a shape (shown in Fig.) by planar development is folded up at a specific position (a) in the central part of the side in the longitudinal direction, and further bent at specific positions (b), (c) on the side in the transversal direction, such that two sides in the transversal direction of the metal conductor 5a face each other and become parallel. By this process, a winding 5 wherein terminal parts 5b-1, 5b-2 and coil parts 5c-1, 5c-2 are formed is obtained. A different winding is sandwiched between the coil parts 5c-1 and 5c-2. In this state, the winding 5 and the different winding are built in a transformer core to constitute a transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for use in a power supply device or the like in which the winding is formed flat to reduce the shape of parts, and which is advantageous for reducing power loss and radiating heat. Regarding the structure.

[0002]

2. Description of the Related Art The most important issue in making a transformer thinner is how to form a thin winding of the transformer. Conventional transformers are provided with a conductor pattern having inductance on an insulating sheet or insulating substrate, and the insulating sheet or insulating substrate is laminated to form a winding of the transformer, thereby reducing the outer shape of the transformer. There is something. An insulating sheet or an insulating substrate having a conductor pattern having such inductance on its surface is called a sheet coil, a printed coil, or the like. FIG. 9 (perspective view) shows an example of a conventional transformer in which the outer shape is reduced by using the sheet coil as a winding.

In the transformer shown in FIG. 9, a primary winding and a secondary winding are formed by a sheet coil laminate 1a in which sheet coils corresponding to respective windings are laminated, and the sheet coil laminate 1a is incorporated in a core 2. Further, the terminals 4a to 4b are inserted into the through holes 3a to 3d of the sheet coil laminate 1a and then soldered. Here, the through-holes 3a to 3d of the sheet coil laminate 1a are formed by through holes that are electrically connected to or insulated from the conductor patterns of each sheet coil. Therefore, the conductor pattern of each sheet coil and the circuit pattern formed on the circuit board are connected to the soldered terminals 4a to 4d.
And through the through holes 3a to 3d.

[0004]

The transformer shown in FIG. 9 uses terminals 4a to 4d for making an electrical connection between a conductor pattern on a sheet coil as a winding and a circuit pattern on a circuit board. Therefore, it is required to solder the through holes 3a to 3d and the terminals 4a to 4d. Here, when a large current is supplied from the secondary winding of the transformer to the load, power loss occurs in the soldered portion between the conductor pattern of the sheet coil and the terminal due to the current flowing therethrough. General solder is made of an alloy containing tin as a main component, and this alloy has a resistivity approximately eight times that of copper used for a conductor pattern or a terminal on a sheet coil. For this reason, the power loss generated at the soldered portion may become a size that cannot be ignored.

The heat generated in the conductor pattern on the sheet coil is conducted not only to the surface of the sheet coil laminate (1a) but also to the terminals and the circuit pattern on the circuit board. The terminals 4a to 4d are radiated into the atmosphere from each surface of the circuit pattern. However, the thermal conductivity of solder is lower than that of copper, and heat is generated due to power loss in the soldered portion, so that the thermal gradient between the conductor pattern on the sheet coil and the metal terminal becomes large. As a result, heat conduction is deteriorated, and there is a possibility that efficient heat radiation of the sheet coil may not be performed. Therefore, the present invention reduces the power loss caused by the soldering portion between the conductor portion and the terminal of the winding, and efficiently conducts the heat generated in the winding and dissipates the heat. It is intended to provide a line structure.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a thin metal conductor which forms a closed loop when unfolded in a plane is folded at the center of a longitudinal side thereof, and a bent portion of the folded metal conductor is used as a terminal. It is characterized by the structure of a winding formed by forming two parallel coils, and the winding is used for a transformer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in the order of manufacturing steps. Insulation is applied to the conductor surface of a thin plate-shaped metal conductor that has a square shape when unfolded in a plane, except for the center of the vertical side. The metal conductor is folded at a predetermined position at the center of the uninsulated vertical side, and further folded so that the planes of the two lateral sides of the metal conductor are opposed and parallel to each other. A predetermined position of the vertical side of the metal conductor extending between the bent portion and the horizontal side is bent. Then, two one-turn coils arranged in parallel are formed using the bent portion of the folding as a terminal. The winding obtained by this step, in which the coil portion and the terminal portion are integrally formed, is used as a winding requiring a large current capacity of the transformer. When assembling the transformer, another winding is inserted between two one-turn coils of the winding to form a winding sandwich structure capable of improving the coupling between the windings.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transformer to which a winding structure according to the present invention is applied, which can reduce the occurrence of power loss due to a soldered portion and efficiently radiate heat generated in a winding. 1 and 2 are shown in FIGS. The transformer shown in the perspective view of FIG.
And the secondary winding is formed by the winding 5, and the sheet coil laminate 1 b and the winding 5 are incorporated in the core 2. The configuration in which the terminals 4a and 4b are inserted into the through holes 3a and 3b of the sheet coil laminate 1b and soldering is performed is the same as the conventional configuration.

Here, the winding 5 is formed as shown in FIG. First, in an unprocessed unfolded state, a thin plate-shaped metal conductor 5a having a square shape in its plane is prepared, and the conductor surface excluding the center of the vertical side is covered with an insulating material 6, and the insulating material 6 is formed. Is applied. The square-shaped metal conductor 5a is folded at a predetermined position (a) in the central portion where insulation is not performed, and then the metal conductor 5a is vertically oriented so that two lateral sides thereof face each other and are parallel to each other. The predetermined positions (b) and (c) of the sides in the direction are bent. Through these two steps, the bent portions of the folding form the terminal portions 5b-1, 2 as the terminals of the winding, and the insulated portions form the coil portions 5c-1, 2 as the coil conductors of the winding. I do.

The winding 5 thus obtained is incorporated into the core 2 with the sheet coil laminate 1b sandwiched between its coil portions 5c-1 and 5c-2, as shown in the sectional view of FIG. . In such a transformer to which the winding structure of the present invention is applied, the winding 5 as the secondary winding is formed by a coil portion (5
c-1 and 2) and the terminal portions (5b-1 and 2) are integrally formed, so that soldering is unnecessary, and the occurrence of power loss and heat in the soldered portion, which has been a problem in the conventional structure, is not required. The increase in the gradient can be eliminated. Also one of transformer
The sandwich structure in which the secondary winding and the secondary winding are alternately arranged and the winding sandwiches the winding is known as an effective means for increasing the coupling between the windings. According to this, since two coil portions 5c-1 and 5c-2 are integrally obtained in the winding 5, there is an advantage that the sandwich structure of the winding can be easily applied.

[0011] Depending on the specifications of the power supply, a plurality of output channels may be required on the secondary side of the transformer. FIG. 4 shows a second embodiment of a transformer to which the winding structure of the present invention is applied in such a case. In FIG.
It is characterized by the configuration of a winding 7 forming an integral secondary winding with respect to the two transformers T2 and T3. FIG. 5 shows an equivalent circuit of an electric circuit including the transformers T2 and T3 by the winding 7. Become like The terminal portion 7b-2 of the winding 7 performs the same function as the intermediate tap of the winding, and the terminal portion 7b-1
2 between terminal portions 7b-2 and 7b-2 and between terminal portions 7b-2 and 7b-3.
It is possible to provide two output channels.

In the winding 7 shown in FIG. 4, a double closed-loop metal conductor 7a as shown in FIG. 6 is folded at a predetermined position (a) and further folded at positions (b) and (c). And each of the first closed loops 7d-1
Is the secondary winding of the transformer T2, and the second closed loop 7d-2 is the secondary winding of the transformer T3. If more output channels are required, a secondary winding may be formed of n-fold closed-loop metal conductors having a number of closed loops corresponding to the number of output channels, and a plurality of transformers may be provided. Good.

One of the important items for reducing the size of the power supply is how to increase the mounting density of the components. If the components can be directly connected to each other without using a circuit pattern on the circuit board, the distance between the components can be reduced, and the mounting density can be increased. The winding structure of the present invention uses a thin metal conductor, and is based on the idea that a part of the metal conductor is used for electrical connection between components instead of a circuit pattern. 7 is a third embodiment of the present invention shown in FIG. In FIG. 7, the winding 8 is formed by using a metal conductor having a wide conductor width in the vicinity of the folding, the terminal portion 8b-1 has a large area, and the winding 8 of the transformer T4 and the diode D The shape is easy to connect directly to.

According to such a configuration, the mounting density of the components can be increased, and at the same time, the power loss due to the soldered portion of the entire device can be reduced. FIG. 8
Is an equivalent circuit of FIG. 7 in which the transformer T4 and the diode D are directly connected.

In each of the embodiments of the present invention described above, the primary winding is a sheet coil laminate 1b, and the secondary winding is a winding (5, 7, 8) obtained by bending a metal conductor according to the present invention.
However, the present invention is not limited to this, and the present invention may be applied to any of the primary winding and the tertiary and subsequent windings.
Further, another winding inserted between the windings according to the structure of the present invention may be formed not by using a sheet coil but by winding a conductive wire. Further, the metal conductor may be insulated by coating with, for example, wax without using the sheet-like insulating material 6 as shown in FIG. If sufficient insulation and safety can be obtained by the case of the device or the like, it is not necessary to particularly insulate the metal conductor.

[0016]

As described above, according to the present invention, two one-turn coils are formed by bending a thin plate-like metal conductor whose expanded state forms a closed loop,
Further, it is intended to obtain a winding in which a terminal portion and a coil portion are integrally formed. This structure eliminates the need for soldering between the conductors of the windings and the terminals, and can eliminate the occurrence of power loss and an increase in thermal gradient at the soldered portions, which are problems in the conventional structure. In addition, 2
Since the two coil portions are integrally obtained, a sandwich structure of the winding which can increase the coupling between the windings can be easily applied. Further, by increasing the conductor width of a part of the metal conductor, direct connection between the parts can be easily performed. In this case, the mounting density of the components in the device can be increased, and at the same time, other components can be connected. There is also an advantage that the power loss due to the soldered portion can be reduced.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a first embodiment of a transformer to which a winding structure according to the present invention is applied.

FIG. 2 is a sectional view of a first embodiment of a transformer to which the winding structure according to the present invention is applied.

FIG. 3 is a comparison diagram of an unprocessed developed state and a processed state of a metal conductor that is a basis of a winding structure according to the present invention.

FIG. 4 is an external perspective view of a second embodiment of the transformer to which the winding structure according to the present invention is applied.

FIG. 5 is an equivalent circuit diagram of a second embodiment of the transformer to which the winding structure according to the present invention is applied.

FIG. 6 is a developed view of a metal conductor before forming a winding of a winding used in the transformer of the second embodiment.

FIG. 7 is an external perspective view of a third embodiment of a transformer to which the winding structure according to the present invention is applied.

FIG. 8 is an equivalent circuit diagram of a third embodiment of the transformer to which the winding structure according to the present invention is applied.

FIG. 9 is a perspective view of the outer shape of a conventional transformer.

[Explanation of symbols]

 1a, 1b Sheet coil laminated body 2 Core 3 (ad) Through hole 4 (ad) (independent) terminal 5 Winding (secondary) 5a Square-shaped metal conductor 5b-1, 2 terminal portion 5c- 1, 2 Coil portion 6 Insulating material 7 Winding (secondary) 7a Double closed loop type metal conductor 7b-1 to 3 Terminal portion 7d-1, 2 Closed loop 8 Winding (secondary) 8b-1, 2 terminal portion ( a) Folding position (b), (c) Folding position

Claims (5)

[Claims] 1. A two-layer coil in which a thin metal conductor forming a closed loop when unfolded in a plane is folded at its center to form two parallel coils, and a bent portion of the folded metal conductor is bent toward the circuit board. The winding structure of the transformer, characterized in that it is used as a terminal. 2. A thin plate-shaped metal conductor that forms a closed loop when unfolded in a plane is folded at the center of its longitudinal side,
The two sides of the metal conductor are bent such that the two sides in the horizontal direction are opposed and parallel to each other, and the two sides of the metal conductor are bent, and the two bent coils are used as terminals. The winding structure of the transformer characterized by forming. 3. A transformer having a plurality of windings,
At least one of the plurality of windings is formed by folding a metal conductor in the form of a closed loop which forms a closed loop when unfolded in a plane at the center of a longitudinal side thereof, and a metal conductor in a horizontal direction of the metal conductor is folded.
The metal conductor is formed by bending the vertical side of the metal conductor so that the sides are opposed and parallel to each other, and forming two coils in parallel with the bent portion of the metal conductor as a terminal. A winding structure for a transformer, wherein another winding is sandwiched between two parallel coils. 4. An area of a terminal of a winding formed by the bent portion is increased by increasing a conductor width near a bent portion of the metal conductor, and another electronic component is directly connected to the terminal. The winding structure of a transformer according to claim 1, wherein the winding structure of the transformer can be performed. 5. The winding of a transformer according to claim 1, wherein the metal conductor has a substantially square shape when unprocessed and unfolded. Construction.