JP2007335453A - High-voltage transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously drive a plurality of loads using a single high-voltage transformer, and to obtain a high-voltage transformer capable of greatly reducing a vertical width size in the direction of a roll without greatly increasing a horizontal width size crossing the direction of a roll. <P>SOLUTION: The high-voltage transformer 11 comprises: first and second bobbins 21A, 21B having a hollow section where secondary-side coils 46A, 46B are wound, respectively; I-shaped first and second cores 30A, 30B inserted into the hollow section of the bobbins 21A, 21B; and an H-shaped third core 31 where a primary-side core 45 is wound directly. An Ni-Zn core made of a highly insulating material is used as the third core 31. A first magnetic path is formed from the first core 30A and the third core 31, and a second magnetic path is formed from the second core 30B and the third core 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high voltage transformer such as an inverter transformer used in a lighting circuit for a discharge lamp for a backlight in a liquid crystal display panel, and more particularly to a double transformer type high voltage transformer in which two transformer parts are integrated. is there.

  In a liquid crystal television, a plurality of discharge lamps are generally driven as a backlight light source. However, the driving is performed using a plurality of step-up transformers, and the brightness of each of the plurality of discharge lamps is displayed on the liquid crystal screen. On the other hand, consideration is given to eliminating unevenness in luminance on the screen so as to be kept uniform.

  By the way, in recent years, the enlargement of liquid crystal televisions is abrupt, and it is necessary to drive more discharge lamps as the light source for the backlight than the conventional one. For this reason, since the installation space and the manufacturing cost of the step-up transformer become excessive, it is desirable to simultaneously turn on two straight tube discharge lamps or U-shaped discharge lamps with a single step-up transformer. The thing of the following patent document 1 is disclosed as a step-up transformer which can light a discharge lamp simultaneously.

  The one described in Patent Document 1 is a combination of two I-type cores and one H-type core. The primary and secondary windings are wound around each I-type core. By combining the core with this, the two closed magnetic paths are configured symmetrically.

  In addition, the step-up transformer described in Patent Document 2 below includes a plurality of secondary winding winding bobbins arranged on both sides of the primary winding winding bobbin. The output to the discharge lamp is secured.

JP-A-2005-311227 JP 2005-39050 A

  However, since the primary winding and the secondary winding are wound only on each I-type core in the one described in Patent Document 1, the H-type core is simply used to make the magnetic path a closed magnetic path. It has only functions. In each I-type core, the primary winding and the secondary winding are wound adjacent to each other in the winding axis direction, so that they tend to be long in this axial direction, and the magnetic path length is also long. There is a risk of sag.

  Moreover, the thing of the said patent document 2 in order to prevent the situation where the high voltage generate | occur | produced from a secondary winding has an influence on a primary winding, withstand voltage between a secondary winding and a primary winding Therefore, it is necessary to ensure a certain distance, and it is inevitable that the width is increased in the direction (width direction) perpendicular to the winding axis direction, and it is difficult to reduce the size of the transformer.

  The present invention has been made in view of the circumstances described above, and a plurality of loads can be simultaneously driven by a single high-voltage transformer, and without significantly increasing the lateral width perpendicular to the winding axis direction. It is an object of the present invention to provide a high-voltage transformer that can greatly reduce the vertical width of the transformer.

The high-voltage transformer of the present invention includes a secondary winding shaft in which the secondary winding is wound in parallel with both sides in the width direction of the primary winding shaft in which the primary winding is wound. Arranged,
The primary winding shaft is constituted by a core made of a highly insulating magnetic material around which the primary winding is directly wound.

  Further, it is desirable that at least one end portion of the core made of the highly insulating magnetic material is provided with a lead groove for the primary winding.

  In addition, it is desirable to dispose an insulating member in a region of the primary side winding shaft that faces the high voltage side of the secondary side winding shaft so that the winding of the primary winding can be prevented. .

  Specifically, for example, an insulating creeping tape that prevents the winding of the primary winding is wound on a region of the primary winding that faces the high-voltage side of the secondary winding. .

  Here, the “highly insulating magnetic material” is a core-forming magnetic material generally referred to as highly insulating, and more insulating than a Mn—Zn core that is not referred to as highly insulating. It shall mean a high magnetic material. Specifically, for example, a Ni-based core such as Ni—Zn corresponds to this.

  Further, in the present invention, even if it is a Mn—Zn core that is not referred to as a high-insulating material, an insulating material is coated on the surface of the core to improve the insulating property, “high-insulating magnetic material” To be included.

  According to the high-voltage transformer of the present invention, the secondary winding is formed by winding the secondary winding in parallel with both sides in the width direction of the primary winding formed by winding the primary winding. Therefore, the length in the direction of the winding axis can be greatly reduced compared to the conventional technique in which the primary side winding and the secondary side winding are sequentially wound in the direction of the winding axis. Can do.

  Further, the primary side winding shaft located at the center is made of a highly insulating magnetic material in which the primary side winding is directly wound without using a bobbin, and thus is wound around the winding shaft. The winding diameter of the primary winding can be greatly reduced, and the width of the transformer can be reduced even when the required insulation withstand voltage distance is secured between the primary winding and the secondary winding. Can be prevented from being greatly widened. In particular, the core constituting the primary winding shaft is made of a highly insulating magnetic material, and the winding wound around the core is considered to be the primary winding. Even if it is wound directly around the core, there is no problem in insulation.

  Hereinafter, a high voltage transformer (inverter transformer) according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a high-voltage transformer according to an embodiment of the present invention, and FIG. 2 is a partial plan view showing a magnetic path configuration thereof.

  The high-voltage transformer 11 of the present embodiment is also called a double leakage transformer, and is an inverter transformer used in a DC / AC inverter circuit for simultaneously discharging and lighting two CCFLs (cold cathode discharge lamps).

  The high-voltage transformer 11 is fitted in the first bobbin 21A and the second bobbin 21B having hollow portions around which the secondary windings 46A and 46B are wound, and the hollow portions of the two bobbins 21A and 21B. The first core 30A and the second core 30B having an I shape to be inserted, and the third core 31 having an H shape formed by directly winding the primary side winding 45 are provided. .

  Here, the primary winding 45 wound directly on the third core 31 and the secondary windings 46A and 46B wound on the bobbins 21A and 21B are H-shaped first windings. The three cores 31 and I-shaped cores 30A and 30B are electromagnetically coupled by a closed magnetic circuit configuration (see FIG. 2).

  The secondary windings 46A and 46B are wound on the bobbins 21A and 21B along the axes of the I-shaped cores 30A and 30B, but a high voltage difference is generated between adjacent windings. In order to prevent dielectric breakdown, it is divided into a plurality of sections in the axial direction, and insulating partition plates 42A and 42B are provided between the sections, so that an insulation distance necessary for preventing creeping discharge is provided. It is secured.

  That is, in each section, for example, the voltage difference is about 330 V (secondary side voltage 2000 V, the number of sections is 6), and the winding start of the secondary side windings 46A and 46B is started in the section. Even when the end of the winding is in contact with the winding while the winding is wound, a sufficient withstand voltage can be secured by the insulating film of the wire.

  The bobbins 21A and 21B have a rectangular cross section and a cylindrical shape. Secondary windings 46A and 46B are wound around the outer periphery of the bobbins 21A and 21B. 40B is provided.

  In addition, by using a plastic resin as the material for forming the bobbins 21A and 21B, the occurrence of burrs can be prevented, and the risk of disconnection in a transformer using a thin wire can be greatly reduced.

  Further, by using the curable resin as the forming material, it is possible to prevent the bobbin from being melted by the solder that joins the windings to the curled terminals 18A and 18B.

  Further, a minute gap is formed between the I-shaped cores 30A and 30B and the H-shaped core 31. The amount of the gap is determined by how much leakage magnetic flux is generated. The gap amount can be made substantially zero.

  These three cores 30A, 30B, 31 are mounted on winding terminal blocks 27A, 27B made of an insulating material.

The start and end of the primary side winding 45 and the start and end of the secondary side windings 46A and 46B are connected to terminal pins 17A and 17B etc. held and fixed to the winding terminal blocks 27A and 27B. Further, for the provisional connection of the windings, the bent terminals 18A, 18B and the like are formed. In addition, the connection aspect to the terminal pin of primary side winding 45 and secondary side winding 46A, 46B is not restricted to this.

  In the high-voltage transformer of the present embodiment, as described above, one H-shaped third core 31 is sandwiched between the two I-shaped first and second cores 30A and 30B. As shown in FIG. 2, the first magnetic path 32A is formed by the first core 30A and the third core 31, and the second core 30B and the third core 31 are formed. Thus, second magnetic paths 32B are respectively formed. Although the first and second magnetic paths 32A and 32B have a minute magnetic gap formed between the first and second cores 30A and 30B and the third core 31, as described above, It is formed as a closed magnetic circuit as a whole.

  Then, the magnetic flux generated in the third core 31 is divided into two and passes through the first and second cores 30A and 30B, whereby the first magnetic path 32A and the second magnetic path 32B is formed.

  Thus, the two CCFLs can be simultaneously discharged and lit by the outputs from the secondary windings 46A and 46B.

  By the way, in this embodiment, it is comprised so that only the secondary side winding 46A, 46B may be wound on the 1st and 2nd cores 30A, 30B via the bobbins 21A, 21B. For this reason, the lengths in the winding axis direction of the first and second cores 30A and 30B are significantly shortened as compared with those of Patent Document 1 described above. As a result, the length of the entire transformer in the winding axis direction can be significantly reduced.

  On the other hand, the primary side winding 45 is configured to be wound directly around the third core 31 without passing through the bobbin, whereby the winding diameter of the primary side winding 45 is equal to the thickness of the bobbin. The lateral width of the transformer can be greatly widened even when the necessary withstand voltage distance is secured between the primary side winding 45 and the secondary side windings 46A and 46B. Can be prevented. Actually, in this embodiment, a sufficient spatial distance is secured between the outermost peripheral part of the primary winding 45 and the outermost peripheral part of each of the secondary windings 46A and 46B. Since the insulation distance that can be prevented is ensured, a high voltage transformer having a high withstand voltage that is unlikely to cause dielectric breakdown can be obtained.

  In addition, by setting it as such a structure, since the number of bobbins reduces, there also exists a secondary effect that a cost can be reduced.

  The reason why the winding can be wound directly around the core in the present embodiment is that the third core 31 is made of a highly insulating material, and the windings to be wound are compared. This is because consideration is given so as not to cause an insulation problem by devising the primary winding 45 to be a low voltage.

  That is, in the present embodiment, Ni—Zn core, which is a highly insulating material, is used as a material for forming the first and second cores 30A, 30B and the third core 31.

  The first and second cores 30A and 30B are formed of a core that is not called a highly insulating material, such as a Mn—Zn core, while the third core 31 is made of a Ni—Zn base. It is also possible to configure the core with a highly insulating material.

  When a Mn—Zn core is used as the material for forming the third core 31, it is difficult to wind the primary winding 45 directly. However, the Ni—Zn core is more difficult than the Mn—Zn core. Since the insulation resistance is extremely large, it is not necessary to ensure insulation through a bobbin.

  In addition, in the inverter transformer, the current of the primary winding 45 needs to be larger than that of the secondary windings 46A and 46B, so that the wire diameter of the primary winding 45 is changed to the secondary winding 46A, The wire diameter is larger than that of 46B, and even if the wire is directly wound around the core, the possibility of disconnection is small.

  Further, in the present embodiment, an H-shaped core is used as the third core 31, and the core itself has a structure in which the flanges are provided at both ends of the winding shaft portion, so that the primary side The winding work of the winding 45 is facilitated.

  Further, as shown in FIG. 4, the third core 31 of the present embodiment corresponds to an end region on the high voltage side (lower side in the figure) (two sections on the high voltage side of the secondary windings 46 </ b> A and 46 </ b> B). The creeping tape (insulating tape) 35 is wound and pasted. The creeping tape 35 has a function of preventing the primary side winding 45 from being wound around this region of the third core 31 and improving the insulation. The spatial distance between the outermost peripheral part and the outermost peripheral part of each of the secondary windings 46A and 46B can be further shortened, and the transformer can be further reduced in the width direction (direction perpendicular to the winding axis direction). Can be promoted.

  In this way, the primary side winding 45 is not wound around the region of the third core 31 corresponding to the high voltage side 2 sections of the secondary side windings 46A and 46B. When the output voltage of the lines 46A and 46B is 2000V, the spatial distance between the outermost peripheral part of the primary winding 45 and the outermost peripheral part of each secondary winding 46A and 46B is 1300 to 1400V. What is necessary is just to set so that a withstand voltage may be ensured.

  In addition, instead of the creeping tape 35, as shown in FIG. 5, the position from the center (secondary windings 46A and 46B of the secondary windings 46A and 46B) from the high voltage side end (lower side in the figure) of the third core 231 by a predetermined distance. An insulating flange 235 is fitted to the high voltage side from the center of two sections) to prevent the primary side winding 45 from being wound around the high voltage side region of the third core 31 and to be insulative. You may make it raise.

  In addition, as shown in FIG. 6, in the present embodiment, the primary winding 45 is drawn out to at least one of the both end portions (saddle portions) 31A and 31B of the third core 31. A wiring groove 51 is formed. It is sufficient for the wiring groove 51 to have a size corresponding to the wire diameter of the primary winding 45. As a result, it is possible to increase the efficiency of space utilization in the height direction (thickness direction) of the transformer.

  Note that the high-voltage transformer of the present invention is not limited to the above-described embodiment, and various other modifications can be made.

  For example, the first and second cores 30A and 30B are formed in an I shape and the third core 31 is formed in an H shape. Any core arrangement may be employed as long as the secondary winding shaft is arranged in parallel on both sides in the width direction of the side winding shaft, thereby forming two closed magnetic paths as shown in FIG. Specifically, for example, as shown in the conceptual diagram of FIG. 3, it is also possible to use what is formed in a generally Japanese character shape by combining one E-shaped core 131 and one I-shaped core 130. is there. In that case, among the three arm parts of the E-shaped core 131 that are parallel to each other, the secondary side windings are wound around the two arm parts located at both ends via the bobbins 121A and 121B, respectively. Two closed magnetic paths 132A and 132B may be configured so that the primary side winding is directly wound around the arm portion (the same creeping tape 135 or the like as described above may be provided).

  Further, instead of the combination of the one E-shaped core and the one I-shaped core, it is also possible to use a combination of two E-shaped cores that are formed in a generally Japanese character shape.

  In addition, the third core 31 and the first and second cores 30A and 30B are made of a Ni—Zn core, which is a high magnetic material. In the high-voltage transformer of the present invention, other high magnetic properties are used. You may make it comprise with what coated the insulating material on the outer surface of magnetic materials which are not high magnetic materials, such as material or a Mn-Zn type | system | group core.

  Further, the cross-sectional (cross-sectional) shape of each core is not limited to a specific shape such as a rectangle, and the cross-sectional shape can be an arbitrary shape such as a circle or an ellipse.

  Furthermore, the high-voltage transformer of the present invention can be applied not only to the inverter transformer but also to various other transformers.

  Also, the load to be driven is not limited to the CCFL described above.

  In the above, creeping tape or scissors are used to prevent the winding of the primary winding around the high voltage side region of the third core 31. However, the high voltage transformer of the present invention is not limited to this. For example, a plastic ring can be used instead of the creeping tape or the hook.

The perspective view which shows the high voltage | pressure transformer which concerns on embodiment of this invention Schematic for demonstrating the closed magnetic circuit structure of the high voltage | pressure transformer which concerns on embodiment of this invention Schematic for demonstrating the structure of the high voltage | pressure transformer which concerns on the change aspect of embodiment of this invention. The top view which expands and shows a part of high voltage transformer which concerns on embodiment of this invention The top view which shows the partial change aspect of embodiment shown in FIG. The partial perspective view for demonstrating the partial structure of the high voltage transformer which concerns on embodiment of this invention

Explanation of symbols

11 High-voltage transformers 17A, 17B Terminal pins 18A, 18B Spinning terminals 21A, 21B, 121A, 121B Bobbins 27A, 27B Winding terminal block 30A First core 30B Second cores 31, 231, Third cores 31A, 31B Ends 32A, 32B, 132A, 132B Magnetic paths 35, 135 Creeping tapes 40A, 40B Plates 42A, 42B Partition plates 45, 245 Primary windings 46A, 46B Secondary windings 51 Wiring grooves 130 I-shaped core 131 E-shaped core 235 鍔 a, b, c, d Direction of magnetic flux

Claims (4)

A secondary winding shaft on which a secondary winding is wound is disposed in parallel with each of both sides in the width direction of the primary winding shaft on which the primary winding is wound;
The high-voltage transformer, wherein the primary winding shaft is constituted by a core made of a highly insulating magnetic material around which the primary winding is wound.   2. The high-voltage transformer according to claim 1, wherein a lead-out groove of the primary winding is provided at at least one end of the core made of the highly insulating magnetic material.   An insulating member is disposed in a region of the primary winding shaft facing the high voltage side of the secondary winding shaft so that the winding of the primary winding can be prevented. The high-voltage transformer according to claim 1 or 2. The insulating creeping tape for preventing the winding of the primary winding is wound around a region of the primary winding facing the high voltage side of the secondary winding. 3. The high-voltage transformer according to 3.

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