JP2006060108A - High voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a mounting area on a circuit board while being able to drive a plurality of loads at the same time, and even when each load fluctuates, it is hardly affected by other load fluctuations and is stable. Get the output.
SOLUTION: A core portion that houses a primary winding 50 and a secondary winding 60 to form a closed magnetic circuit includes a pair of side legs 32a and 32b erected from a base portion 31 and the pair of sides. A pair of upper and lower E-type cores 30a and 30b having a central leg 33 disposed within the leg interval and disposed so that their open surfaces face each other, and within the interval between the pair of upper and lower E-type cores And an I-type core 40 disposed on the surface. A winding frame portion 80 for winding the primary winding 50 and the secondary winding 60 is provided on the outer periphery of the center leg of the pair of upper and lower E-shaped cores. The primary winding 50 wound on the winding frame portion 80 in two upper and lower stages is wound so that the magnetic flux directions are the same in the I-type core 40 portion.
[Selection] Figure 5

Description

  The present invention relates to a high voltage transformer, and more particularly to a high voltage transformer used in a lighting circuit for lighting a backlight of a liquid crystal display device.

  A liquid crystal display device used for a TV monitor or a personal computer monitor includes a lighting circuit for lighting a backlight. This lighting circuit generally uses a leakage transformer, which is a high-voltage transformer, in order to generate a high voltage.

  Further, since a plurality of backlights are used in recent liquid crystal display devices, it is necessary to prepare a lighting circuit in accordance with the number of backlights, and two secondary windings are arranged in the substrate plane direction. A leakage transformer capable of obtaining an output has been developed (for example, see Patent Document 1).

  The leakage transformer described in Patent Document 1 has a configuration in which two secondary windings are arranged on a gantry in the substrate plane direction, and the primary winding is wound on the upper part of both secondary windings. . For this reason, when the leakage transformer is mounted on the circuit board of the electronic device, there is a problem that the mounting area increases.

  Therefore, the present inventor provides a leakage transformer that can be reduced in size and reduced in mounting area with respect to the circuit board by providing a multi-stage bobbin that can be wound with the secondary windings stacked one above the other. It has already been developed (Japanese Patent Application No. 2003-393673).

  The leakage transformer includes an E-type core having a pair of side legs erected from a base portion and a central leg disposed within a distance between the pair of side legs, and an upper open surface of the E-type core is closed. And an I-type core disposed so as to have a configuration in which an outer periphery of the center leg of the E-type core is provided with a winding frame portion that winds the secondary winding up and down. .

JP 2002-299134 A

  By the way, in recent liquid crystal display devices, it is required to reduce the area of the frame portion surrounding the liquid crystal display portion, to reduce the overall size even with the same screen size, and to be lighter and more compact. ing. For this reason, the leakage transformer used in the lighting circuit is also required to be further downsized in order to reduce the mounting area on the circuit board.

  As described above, the leakage transformer described in Patent Document 1 has a problem in that the mounting area with respect to the circuit board increases because two secondary windings are arranged in the board plane direction.

  In addition, by providing a multi-stage bobbin capable of winding the secondary winding vertically, the leakage transformer that attempts to reduce the mounting area on the circuit board has two secondary windings stacked vertically. However, when the load of one secondary winding fluctuates, the other secondary winding is also affected by this, and it is difficult to balance the magnetic flux. There was a case.

  The present invention has been proposed in view of the circumstances described above, and while being capable of simultaneously driving a plurality of loads, while reducing the mounting area for the circuit board and even when each load fluctuates, An object of the present invention is to provide a high-voltage transformer that is less affected by other load fluctuations and can obtain a stable output.

In order to achieve the above-described object, the high-voltage transformer of the present invention includes a core portion that houses a primary winding and a secondary winding to form a closed magnetic circuit, and includes the primary winding and the secondary winding. In the high voltage transformer that performs electromagnetic induction between
The core portion has a pair of side legs erected from the base portion and a center leg disposed within a distance between the pair of side legs, and is disposed so that open surfaces face each other. A pair of upper and lower E-type cores, and an I-type core disposed within the interval between the pair of upper and lower E-type cores,
On the outer periphery of the central leg of the pair of upper and lower E-shaped cores, a winding frame portion for winding the primary winding and the secondary winding, respectively,
The primary winding wound around each of the winding frame portions is wound so that the direction of magnetic flux is the same in the I-type core portion.

Here, the winding frame portion can be configured by a secondary winding portion having two upper and lower stages and a primary winding portion disposed on the outer peripheral side of the secondary winding portion.
The upper and lower secondary winding portions are integrally formed with a gantry supporting the core portion,
It is possible to provide an insertion hole through which the I-type core is inserted in the interval between the upper and lower secondary winding portions.

  In the high-voltage transformer according to the present invention, an E-type core, an I-type core, and an E-type core are arranged in order from the lower side, and a primary winding and a secondary are respectively provided on the outer periphery of the center leg of each E-type core. A winding frame part for winding the winding is provided. As described above, since the plurality of secondary windings are stacked one above the other, the mounting area with respect to the circuit board can be reduced.

  Further, since the primary windings wound around the upper and lower winding frame portions are wound so that the magnetic flux directions are the same in the I-type core portion, the load on one of the secondary windings fluctuated. However, the other secondary winding is not affected by this, and a stable output can be secured.

  In addition, winding can be easily performed by forming a winding frame portion with the upper and lower secondary winding portions and the primary winding portion disposed on the outer peripheral side of the secondary winding portion. Thus, the manufacturing process can be simplified and the manufacturing cost can be reduced.

  Also, the manufacturing process is simplified by forming the upper and lower secondary winding sections integrally with the gantry and providing an insertion hole through which the I-type core is inserted in the space between the upper and lower secondary winding sections. Thus, the manufacturing cost can be further reduced.

Hereinafter, a leakage transformer will be described as an example of an embodiment of a high-voltage transformer according to the present invention with reference to the drawings.
1 to 5 show a leakage transformer according to an embodiment of the present invention. FIG. 1 is a perspective view of the leakage transformer, FIG. 2 is an exploded front view of a gantry and a winding frame, and FIG. FIG. 4 is an exploded perspective view showing a part of the core portion, and FIG. 5 is an explanatory view showing a longitudinal section of the winding wound around the core portion and the winding frame portion.

The leakage transformer according to the present embodiment is formed such that an air gap is provided between the center leg of the E-type core and the I-type core, thereby generating a slight leakage magnetic flux. The leakage transformer according to the present embodiment is used for a lighting circuit for lighting a backlight of a liquid crystal display device, and is generally called a double leakage transformer, and two CCFLs (cold cathode discharge lamps). ) Are used in a DC / AC inverter circuit for simultaneously discharging and lighting.
As shown in FIGS. 1 to 5, the leakage transformer 10 is configured by attaching a core portion made of a magnetic member on a base 20 having an insulating property.

  The core portion is a member that houses the primary winding 50 and the secondary winding 60 to form a closed magnetic circuit, and is a distance between the pair of upper and lower E-type cores 30a and 30b and the pair of upper and lower E-type cores 30a and 30b. And an I-type core 40 disposed therein. The E-type cores 30a and 30b are vertically symmetric, and are disposed within a distance between the pair of side legs 32a and 32b erected from the base 31 and the pair of side legs 32a and 32b. The central leg 33 is provided so that the open surfaces face each other.

  Here, the E-type cores 30a and 30b and the I-type core 40 are formed using, for example, ferrite. The core part is supported on a gantry 20 made of an insulating member, and the gantry 20 is provided with terminal portions 70a and 70b for connecting the ends of the primary winding 50 and the secondary winding 60. It has been. The terminal portions 70a and 70b are provided on the left and right side portions of the gantry 20, respectively, and a plurality of binding pins 71a to 71d for binding the ends of the windings and a plurality of terminal pins 72a connected to a circuit board or the like. To 72i.

Each E-type core 30a, 30b is provided with a winding frame portion 80 for winding the primary winding 50 and the secondary winding 60 in the upper and lower stages on the outer periphery of the center leg 33, respectively.
The winding frame portion 80 is composed of a secondary winding frame portion 90 that forms a double-drum type with two upper and lower stages, and a cylindrical primary winding frame portion 100 that is attached to the outer periphery of the secondary winding frame portion 90. .
Further, the secondary winding frame part 90 includes a lower secondary winding part 90a and an upper secondary winding part 90b. The primary winding frame part 100 includes a lower secondary winding part 90a and an upper secondary winding part 90b. A lower primary winding portion 100a and an upper primary winding portion 100b facing the secondary winding portion 90b are provided.

The lower secondary winding portion 90 a and the upper secondary winding portion 90 b are formed so as to be integrated with the gantry 20. Further, on the outer periphery of the secondary winding frame portion 90, a total of four flange portions 91 to 94 are formed at the upper and lower end portions and the intermediate portion, and the lower end flange portion 91 and the lower intermediate flange portion 92 are A lower secondary winding portion 90 a is formed therebetween, and an upper secondary winding portion 90 b is formed between the upper end flange portion 94 and the upper intermediate flange portion 93.
Note that the lower secondary winding portion 90a and the upper secondary winding portion 90b can be formed separately.
The lower primary winding portion 100a and the upper primary winding portion 100b are integrally formed in a cylindrical shape. Further, on the outer periphery of the primary reel unit 100, a total of four flanges 101 to 104 are formed at the upper and lower ends and the intermediate part, and the lower end flange 101 and the lower intermediate flange 102 A lower primary winding portion 100 a is formed therebetween, and an upper primary winding portion 100 b is formed between the upper end flange portion 104 and the upper intermediate flange portion 103.
Note that the lower primary winding portion 100a and the upper primary winding portion 100b can be formed separately.

  On the outer periphery of the lower secondary winding portion 90a and the upper secondary winding portion 90b, a lower primary winding portion 100a and an upper primary winding portion 100b that are integrally formed in a cylindrical shape are disposed. The lower primary winding portion 100a and the upper primary winding portion 100b are for winding the primary winding 50. The lower secondary winding portion 90a and the upper secondary winding portion 90b The primary winding 50 is disposed on the outer peripheral side of the secondary winding 60 by fitting the lower primary winding portion 100a and the upper primary winding portion 100b integrally molded into a cylindrical shape on the outer peripheral side. can do.

  Here, the primary winding 50 wound around the lower primary winding portion 100a and the upper primary winding portion 100b is wound so that the magnetic flux directions are the same in the I-type core 40 portion. .

  Therefore, as indicated by arrows in FIG. 5, in the lower secondary winding portion 90a and the lower primary winding portion 100a, a magnetic flux from the upper side to the lower side is formed in the central leg 33 portion of the E-type core 30a. The base part 31 of the E-type core 30a forms a magnetic flux from the center part to the outer peripheral part, and the side legs 32a and 32b of the E-type core 30a form a magnetic flux from the lower side to the upper side. In each portion, a magnetic flux is formed from the outer periphery toward the center. On the other hand, in the upper secondary winding portion 90b and the upper primary winding portion 100b, a magnetic flux from the lower side to the upper side is formed in the central leg 33 portion of the E-type core 30b, and in the base portion 31 of the E-type core 30b, respectively. A magnetic flux from the center to the outer periphery is formed, a magnetic flux from the upper side to the lower side is formed at the side legs 32a and 32b of the E-type core 30b, and a magnetic flux from the outer periphery to the center at the I-type core 40 portion. Is formed.

  Thus, in the I-type core 40 portion where the lower secondary winding portion 90a and the lower primary winding portion 100a and the upper secondary winding portion 90b and the upper primary winding portion 100b have a common magnetic path. The direction of the magnetic flux becomes the same, and the load on one secondary winding 60 (for example, the secondary winding 60 wound around the upper secondary winding portion 90b) fluctuates, and the other secondary winding 60 (for example, The secondary winding 60) wound around the lower secondary winding portion 90a is not affected by this, and a stable output can be secured.

Further, as shown in FIG. 2, the secondary winding frame 90 has a direction perpendicular to the axial direction so as to be positioned between the lower secondary winding 90a and the upper secondary winding 90b. An I-type core insertion hole 95 for inserting the I-type core 40 is provided.
Similarly, the I-type core 40 is inserted into the primary winding frame portion 100 in a direction orthogonal to the axial direction so as to be positioned between the lower primary winding portion 100a and the upper primary winding portion 100b. An I-type core insertion hole 105 is provided.

  In the example shown in FIG. 2, the I-type core insertion hole 95 and the I-type core insertion hole 105 are provided in the vicinity of the center in the direction orthogonal to the axial direction. The core insertion hole 105 is preferably formed while being shifted from the axial direction toward the terminal portion 70b.

  Here, since the magnetic flux density of the I-type core 40 is proportional to the cross-sectional area of the I-type core 40, it is necessary to make the cross-sectional area of the I-type core 40 greater than or equal to a predetermined value in order to ensure a predetermined magnetic flux density. is there. In this case, the height of the leakage transformer 10 can be reduced by making the longitudinal cross-sectional shape of the I-type core 40 horizontally rather than vertically long.

That is, if the longitudinal cross-sectional shape is expanded in the height direction in order to ensure a predetermined cross-sectional area in the I-type core 40, the height of the leakage transformer 10 is increased. For this reason, it becomes necessary to widen the longitudinal cross-sectional shape of the I-type core 40 in the horizontal direction.
However, when the vertical cross-sectional shape of the I-type core 40 is expanded in the horizontal direction, when the secondary winding 60 is induced in the terminal portion 70a having a winding induction groove (not shown), the secondary winding 60 contacts the I-type core 40.

  Therefore, the I-type core insertion hole 95 is formed to be shifted from the terminal portion 70a having a winding guide groove (not shown) to the opposite side (terminal portion 70b side), thereby forming the secondary winding 60 in the terminal portion 70a. When induction is performed, the end portion of the secondary winding 60 can be easily processed without the secondary winding 60 being in contact with the I-type core 40.

  In order to manufacture the leakage transformer 10 of the present embodiment, first, the secondary winding 60 is wound in the order of the lower secondary winding portion 90a and the upper secondary winding portion 90b, and both ends of the secondary winding 60 are connected. Pull it out. On the other hand, the primary winding 50 is wound around the lower primary winding portion 100a and the upper primary winding portion 100b, respectively, and both ends of the primary winding 50 are drawn out.

Next, the primary winding frame 100 (the lower primary winding portion 100a and the upper primary winding) formed integrally with the outer periphery of the lower secondary winding portion 90a and the upper secondary winding portion 90b in a cylindrical shape. The winding portion 100b) is fitted to form the winding frame portion 80.
Next, the winding frame portion 80 is fitted into the lower E-shaped core 30 a, and the I-type core 40 is sequentially inserted into the I-type core insertion hole 105 and the I-type core insertion hole 95, so In addition, the I-type core 40 is set in a skewered state.

Next, the upper E-type core 30b is fitted from above the winding frame portion 80 so that the upper and lower E-type cores 30a, 30b and the I-type core 40 are integrated.
Finally, the end portions of the primary winding 50 and the secondary winding 60 are connected to the terminal portions 70a and 70b to complete the leakage transformer 10. Thus, according to the leakage transformer 10 according to the present embodiment, manufacturing is easy and the cost can be reduced.

  The E-type cores 30a and 30b and the I-type core 40 are formed of ferrite, but the core forming material is not limited to this, and can be selected from other general core materials. For example, materials such as permalloy, sendust, and iron carbonyl can be used, and a dust core obtained by compression molding these fine powders can also be used.

  Further, the use of the high-voltage transformer according to the present invention is not limited to the leakage transformer, but can be applied to other types of transformers.

The perspective view of the leakage transformer which concerns on embodiment of this invention The front view which decomposes | disassembles and shows the mount frame and reel part of the leakage transformer which concern on embodiment of this invention Sectional drawing which decomposes | disassembles and shows the winding frame part of the leakage transformer which concerns on embodiment of this invention The disassembled perspective view which shows a part of core part of the leakage transformer which concerns on embodiment of this invention Explanatory drawing which shows the longitudinal cross-section of the coil | winding wound by the core part and winding frame part of the leakage transformer which concerns on embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Leakage transformer 20 Mount 30a, 30b E type core 31 Base part 32a, 32b Side leg 33 Central leg 40 I type core 50 Primary winding 60 Secondary winding 70a, 70b Terminal part 71a-e Binding pin 72a-i Terminal pin 80 Winding frame portion 90 Secondary winding frame portion 90a Lower secondary winding portion 90b Upper secondary winding portion 91 to 94 Hook 95 I-type core insertion hole 100 Primary winding frame portion 100a Lower primary winding Line part 100b Upper side primary winding part 100-104 ridge part 105 I-type core insertion hole

Claims (3)

In a high-voltage transformer that includes a core portion that houses a primary winding and a secondary winding to form a closed magnetic circuit, and performs electromagnetic induction between the primary winding and the secondary winding.
The core portion has a pair of side legs erected from the base portion and a center leg disposed within a distance between the pair of side legs, and is disposed so that the open surfaces face each other. A pair of upper and lower E-type cores, and an I-type core disposed within the interval between the pair of upper and lower E-type cores,
On the outer periphery of the central leg of the pair of upper and lower E-shaped cores, a winding frame portion for winding the primary winding and the secondary winding, respectively,
The high-voltage transformer, wherein the primary winding wound around each of the winding frame portions is wound so that the direction of magnetic flux is the same in the I-shaped core portion.   2. The high voltage according to claim 1, wherein the winding frame portion includes a secondary winding portion having two upper and lower stages and a primary winding portion disposed on an outer peripheral side of the secondary winding portion. Trance. The upper and lower secondary winding sections are formed integrally with a frame that supports the core section,
The high-voltage transformer according to claim 1 or 2, wherein an insertion hole for inserting the I-type core is provided in an interval between the upper and lower secondary winding portions.

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