JP3520566B2 - Drive transformer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transformer composed of a U-shaped core, a four-legged core and a bobbin used for a switching power supply, and more particularly, it is restricted by the shapes of the U-shaped core and the four-legged core. In order to avoid it, the present invention relates to a drive transformer in which the shape of a metal fitting for fixing both cores has been improved so that almost the center of the side surfaces of both cores can be uniformly pressurized in a limited space. More specifically, the present invention relates to a drive transformer that prevents a variation in inductance and enables stable operation by using a fixing metal fitting that can evenly pressurize a U-shaped core and a four-legged core. .

[0002]

2. Description of the Related Art Conventionally, drive transformers have been used in the power supply section of various electronic devices. Generally, this drive transformer is composed of a U-shaped core, a four-legged core and a bobbin.

FIG. 5 is a diagram showing a usage example of a power supply unit having a built-in drive transformer. In the figure, TV is a television receiver, VC is a video camera,
SP indicates a switching power supply unit, PL indicates a power plug, and CN indicates an outlet.

As shown in FIG. 5, for example, when the television receiver TV and the video camera VC are connected to each other, the switching power supply unit S is connected via the power plug PL.
Connect P to an outlet CN for AC power. The switching power supply unit SP has a built-in drive transformer and is supplied from the outlet CN side, for example, AC1.
The voltage of 00V is converted into the required voltage and the video camera V
Supplied to C. Next, the configuration of a conventional drive transformer will be described with reference to the drawings.

FIG. 6 is a perspective view showing an example of the appearance of a drive transformer conventionally used for a switching power supply or the like. In the figure, 1 is a U-shaped core, 2 is a four-legged core, 3 is a bobbin, and arrows A and A '.
Indicates the press-fitting direction of the fixing metal fitting, and B and C indicate the pressing points.

As shown in FIG. 6, the conventional drive transformer is composed of a U-shaped core 1, a four-legged core 2 and a bobbin 3 at three points. The bobbin 3 is arranged in the center, and the U-shaped core 1 and the four-legged core 2 are arranged opposite to each other on both side surfaces thereof.

The U-shaped core 1 is a soft magnetic material (see FIG. 3, which will be described later) in which the overall shape seen from above is U-shaped, and the four-legged core 2 is located on the bobbin 3 side. A "+" type groove is formed, and it is a soft magnetic body as if four legs were formed (see FIG. 3 below). In the drive transformer, since the bobbin 3 arranged in the center has a complicated shape, such a U-shaped core 1 and a four-legged core 2 are used.

In this drive transformer, it is necessary to fix the U-shaped core 1 and the four-legged core 2. Conventionally, the facing surfaces of the two cores 1 and 2 are adhered to each other, or separate fixing metal fittings (described later) are used. (Shown in FIG. 7). However, both cores 1 and 2
In the method of adhering the opposing surfaces of the above, it is necessary to use a highly reliable adhesive.

However, since a highly reliable adhesive needs a heat curing treatment, it has to perform an off-line work, which disadvantageously increases the manufacturing lead time. On the other hand, the method of using a separate fixing metal fitting is roughly classified into those that use a leaf spring,
It is classified into two types, one that uses wire. Next, the fixing metal fittings that have been conventionally used are shown in FIG.
Described in.

FIG. 7 is an external view of a fixing metal fitting used in a conventional drive transformer. (1) is a U-shaped metal fitting, (2) is a box-shaped metal fitting, and (3) is a wire (beam). It is a perspective view which shows the metal fitting comprised by the (gane). In the figure, 4 is a U-shaped metal fitting, 4a is an upper surface portion, 4b is a side surface portion, 4c is a pressing portion, 5 is a box-shaped metal fitting, 5a is a flat plate portion, 5b is a protruding pressing portion, and 6 is a wire metal fitting. , 6a is an upper surface portion, 6b is a side surface portion, 6
c indicates a pressing portion.

As described above, in the drive transformer, it is particularly necessary to fix the two parts, that is, the U-shaped core 1 and the four-legged core 2, as shown in FIGS. 7 (1) to 7 (3). Various fixing metal fittings are used. For example, in the case of the "U-shaped metal fitting 4" composed of a leaf spring as shown in FIG. 7 (1), it is press-fitted as shown by arrows A and A'in FIG.

In this case, the pressing portion 4 of the U-shaped metal fitting 4
c contacts the vicinity of the position B of the U-shaped core 1, and also contacts the corresponding positions of the four-legged core 2 in the same manner.
To pinch. As described above, due to the restriction of the shape of the bobbin 3, in the case of the U-shaped metal fitting 4, only one end of each of the U-shaped core 1 and the four-legged core 2 is pressed and pinched.

Further, as shown in FIG. 7 (2), in the case of the "box-shaped metal fitting 5" similarly made of a leaf spring, the U-shaped core 1 and the four-legged core 2 are fixed so as to surround them from the outside. That is,
One protrusion 5b of the box-shaped metal fitting 5 presses the position C of the U-shaped core 1 shown in FIG. Similarly, the other protrusion 5b
Also presses the corresponding position of the four-legged core 2 (the back side in FIG. 6).

Thus, if the box-shaped metal fitting 5 is used, U
It is possible to press the mold core 1 and the four-legged core 2 from the outer circumference, but since the outer shape of the transformer becomes large,
There is a problem in that there are restrictions on mounting and cost increases. Further, as shown in FIG. 7 (3), even in the case of "wire fitting 6" made of wire, the basic problem is
This is the same as the U-shaped metal fitting 4 shown in FIG. 7 (1) above, and moreover, as a problem in the manufacturing process, the transformer is difficult to assemble, and as a result, an increase in cost cannot be avoided.

[0015]

In the conventional drive transformer, the U-shaped core 1 arranged on both sides of the bobbin.
It is necessary to fix the two parts of the two-legged core and the four-legged core 2 together, and in the method of fixing with an adhesive and the method of using the fixing metal fittings shown in FIGS. 7 (1) to (3), respectively. There is a problem in that the center of the U-shaped core 1 and the four-legged core 2 cannot be pressed or pinched due to the cost increase or the restriction due to the shape of the bobbin. In the present invention, by improving the shape of the fixing metal fitting, the center of the U-shaped core 1 and the four-legged core 2 arranged opposite to each other can be accurately adjusted without increasing the size of the transformer or increasing the cost. It is an object of the present invention to provide a drive transformer that can be pressed and pinched to.

[0016]

According to the present invention, firstly,
A drive transformer comprising a U-shaped core, a four-legged core, and a bobbin, wherein the U-shaped core and the four-legged core are fixed by a metal fitting composed of an upper surface plate, a side surface plate, and a pressing portion. Is located at one end of the upper surface of the U-shaped core and the four-legged core, the side plate is formed in a direction oblique to the vertical direction of the upper plate, and the pressing portion connected to the upper plate by the side plate is The two cores are arranged so as to be located substantially at the centers of the side surfaces.

Secondly, in the first drive transformer, the pressing portion of the metal fitting is formed on a part of the side plate.

Thirdly, in the first drive transformer, the pressing portion of the metal fitting is formed independently of the side plate.

Fourthly, in the first drive transformer, the side plate of the metal fitting is formed substantially at a right angle when viewed from the side.

Fifth, in the first drive transformer, the side plate of the metal fitting is formed in a substantially arc shape when viewed from the side.

[0021]

According to the present invention, in the conventional transformer using the fixing metal fitting, it is not possible to press and clamp the substantially middle portions (center positions) of the side surfaces of the cores 1 and 2 in a limited space. Focusing on the fact that the inductance fluctuates, the side plate is formed so that the pressing portion that presses / pinches both cores 1 and 2 from the side is at an angle with respect to the vertical direction of the top plate of the metal fitting. (Inventions 1 to 5).

[0022]

Embodiment 1 Next, the drive transformer of the present invention will be described in detail with reference to the drawings. This embodiment mainly corresponds to the invention of claim 1, but is also related to the inventions of claims 2 to 5. In this first embodiment, a U-shaped core 1 and a four-legged core 2 are used.
By slanting the shape of the side plate of the metal fitting for fixing and, the upper surface plate of the metal fitting for fixing located at one end of the upper surfaces of the U-shaped core 1 and the four-leg core 2 and the side plate are connected to the upper surface plate. , Using a fixing metal fitting having both U-shaped cores and both pressing portions for pressing and sandwiching the four-legged core at substantially center positions of side surfaces of the both cores 1 and 2 (positions displaced from the vertical direction of the top plate) However, it is characterized in that the side surfaces of both cores 1 and 2 are evenly pressed.

FIG. 1 is a view showing an embodiment of the drive transformer of the present invention, and is a perspective view showing a state where the drive transformer is mounted on a switching power supply circuit board. Reference numerals in the figure are the same as those in FIG. 6, 7 is a switching power supply circuit board, 8 is a power plug, 9 is a code, 11 is a drive transformer, and 12 is a fixing metal fitting.

As shown in FIG. 1, the drive transformer 11 of the present invention uses inclined metal fittings as the metal fittings 12 for fixing the U-shaped core 1 and the four-legged core 2. In the drive transformer 11 of the present invention, the bobbin, the U-shaped core 1,
The restriction that the centers of both cores 1 and 2 cannot be pressed and pinched due to the shape of the four-legged core 2 is avoided.

FIG. 2 is a view showing the detailed structure of an embodiment of the fixing metal fitting 12 shown in FIG. 1, where (1) is a top view, (2) is a front view, and (3) is a side view. It is a figure. In the figure, 12a is a top plate, 12b and 12b 'are inclined side plates, and 12c and 12c' are pressing portions thereof.

As shown in FIGS. 2 (1) to 2 (3), the fixing metal fitting 12 shown in FIG. 1 has a top plate 12a for fixing the upper portion of the U-shaped core 1 and the four-legged core 2 as in the conventional case. , The U-shaped core 1 and the four-legged core 2, the pressing portions 12c, 12c 'which are respectively brought into contact with the central positions of the side surfaces, and the inclined side surface plate 12b connecting the upper surface plate 12a and both pressing portions 12c, 12c'. , 1
2b '. In this way, the pressing portions 12c, 12c 'that press the central positions of the sides of the U-shaped core 1 and the four-legged core 2 that are arranged so as to face each other on both sides of the bobbin 3.
If the fixing metal fitting 12 with the
An even force will be applied to the center position of 2,
There is no inconvenience as in the past.

FIG. 3 shows the fixing metal fitting 12 shown in FIG.
6A and 6B are views for explaining a work procedure for incorporating the drive transformer 11, wherein FIG. 1A is a front view before incorporation and FIG. 2B is a perspective view after incorporation. The reference numerals in the drawings are the same as those in FIGS. 2 and 6, and the arrow D indicates the pressing direction of the fixing fitting 12.

The front view shown in FIG. 3 (1) corresponds to the view seen from the right side in FIG. 6, and FIG.
The perspective view of (2) shows a state viewed from the same direction as in FIG. 6, and the bobbin is omitted in the figure. Also in the drive transformer of the present invention, the direction of the arrow D that presses the fixing metal fitting 12 for fixing the U-shaped core 1 and the four-legged core 2 is almost the same as that of the conventional metal fitting. Since the positional relationship between the face plate 12a and the pressing portions 12c and 12c 'is slanted, it is not a direction directly below where the top plate 12a is fixed, but a slightly slanted direction.

When the fixing metal fitting 12 is pressed, FIG.
As shown in FIG. 5, the upper surface plate 12a is fixed at the same position as in the conventional case, but the pressing portions 12c and 12c 'are brought into contact with each other at substantially central positions of the U-shaped core 1 and the four-legged core 2.
As described above, in the first embodiment, the fixing metal fitting 12
As the upper surface plate 12a and pressing portions 12c, 12c 'for pressing the central positions of the sides of the U-shaped core 1 and the four-legged core 2
The case of the metal fitting including the upper surface plate 12a and the inclined side surface plates 12b and 12b 'connecting the pressing portions 12c and 12c' has been described (the invention of claim 1).

The relationship between the side plate 12b (12b ') and the pressing portion 12c (12c') will be described below with reference to FIG.
Then, the pressing portion 12c is formed on a part of the side plate 12b (12b ').
The case of forming (12c ') (the invention of claim 2) is shown. However, it is also possible to provide a pressing portion independent of the side plate and connect the upper plate with the side plate (claim 3).
Invention, see FIG. 4 below).

[0031]

Second Embodiment Next, a second embodiment will be described. This embodiment mainly corresponds to the inventions of claims 3 to 5. In the first embodiment, the inclined side plates 12b, 12 connecting the upper plate 12a and the pressing portions 12c, 12c '.
The case where b'is almost a straight line has been described.

Also in this second embodiment, the upper surface plate 12a and both pressing portions 12c and 12c 'are formed by the U-shaped core 1 and the four-legged core 2.
The point of contacting and pressing at the above predetermined position is the same, but it is characterized in that the shapes of the side plates 12b and 12b 'are changed (the inventions of claims 4 and 5). The basic structure and operation are the same as those of the first embodiment, but the shape of the side plate is modified.

FIG. 4 is a side view showing another embodiment of the fixing metal fitting used in the drive transformer of the present invention. In the figure, 13 is a second metal fitting, 13a is a top plate thereof, 13b is a side plate, 13c is a pressing portion, and 14 is a third plate.
14a is a top plate, 14b is a side plate,
Reference numeral c is a pressing portion, 15 is a fourth metal fitting, 15a is an upper surface plate thereof, 15b is a side surface plate thereof, and 15c is a pressing portion.

FIG. 4 shows another embodiment of the fixing fitting 12 shown in FIGS. 1 and 2. For example, in the case of the second metal fitting 13, the side surface plate 13b is "key-shaped", but the positional relationship between the upper surface plate 13a and the pressing portion 13c is the same as in the first embodiment, and the pressing portion is the same. 13c contacts and presses in the center position on the U-shaped core 1 and the four-legged core 2 (the invention of claim 4). Further, in the case of the third metal fitting 14, the side plate 14b is "arc-shaped", and the pressing portion 14c contacts and presses at the center position on the U-shaped core 1 and the four-leg core 2 (claim 4). Invention).

In the case of the fourth metal fitting 15, the side plate 15b
Is obliquely formed, and the wider pressing portion 15c contacts and presses at the central position on the U-shaped core 1 and the four-legged core 2 (the invention of claim 3). As described above, the side plates 13a, 14
Although a and 15a can have any shape, in any case, as in the first embodiment, the top plate (for example, 13a) and the pressing portion (for example, 13c) are arranged in the vertical direction of the transformer. Is inclined, and the pressing part (for example, 13c)
Have a common point of contacting and pressing at the center position on the U-shaped core 1 and the four-legged core 2.

[0036]

In the drive transformer of the present invention, the metal fittings for fixing the U-shaped core and the four-legged core are improved so that the upper plate and the two cores are displaced from the vertical direction (diagonal position). The pressing portion of the metal fitting presses and clamps both cores at substantially the center position (center position) of the side surface of the. Therefore, it becomes possible to pressurize both cores evenly,
The inductance is stable and high reliability is obtained.

Moreover, the structure and the like are simple and the number of parts does not increase, so that miniaturization is also realized. In addition, since the assembling work is easy, it is advantageous in terms of cost and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a drive transformer of the present invention, and is a perspective view showing a state where the drive transformer is mounted on a switching power supply circuit board.

FIG. 2 is a diagram showing a detailed structure of an embodiment of the fixing metal fitting 12 shown in FIG.

FIG. 3 is a diagram illustrating a work procedure for incorporating the fixing metal fitting 12 shown in FIG. 2 into the drive transformer 11.

FIG. 4 is a side view showing another embodiment of the fixing metal fitting used in the drive transformer of the present invention.

[FIG. 5] Regarding a power supply unit having a built-in drive transformer,
It is a figure which shows the one usage example.

FIG. 6 is a perspective view showing an example of the appearance of a drive transformer conventionally used for a switching power supply or the like.

FIG. 7 is a view showing an appearance of a fixing metal fitting used in a conventional drive transformer.

[Explanation of symbols]

7 Switching power supply circuit board 8 power plug 9 codes 11 Drive transformer 12 Fixing metal fittings 12a Top plate 12b and 12b 'inclined side plates 12c and 12c 'pressing part

Claims (5)

(57) [Claims] 1. A drive transformer, comprising: a U-shaped core, a four-legged core, and a bobbin, wherein the U-shaped core and the four-legged core are fixed by metal fittings composed of a top plate, a side plate, and a pressing portion, An upper surface plate of the metal fitting is located at one end of an upper surface of the U-shaped core and the four-legged core, and a side surface plate is formed obliquely to a vertical direction of the upper surface plate, and the side surface plate is connected to the upper surface plate. The drive transformer, wherein the pressed portion is located substantially at the center of the side surfaces of the two cores. 2. The drive transformer according to claim 1, wherein the pressing portion of the metal fitting is formed on a part of a side plate. 3. The drive transformer according to claim 1, wherein the pressing portion of the metal fitting is formed independently of the side plate. 4. The drive transformer according to claim 1, wherein the side plate of the metal fitting is formed substantially at a right angle when viewed from the side. 5. The drive transformer according to claim 1, wherein the side plate of the metal fitting is formed in a substantially arc shape when viewed from the side.