JP2009212470A - Inverter transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variations of a leakage inductance of two secondary wiring with no special wiring management such as space winding when a wind remaining part occurs in an outermost layer in a two-output type inverter transformer whose secondary windings are located on both sides of a primary winding. <P>SOLUTION: The two-output type inverter transformer includes a magnetic core forming a closed magnetic circuit, a bobbin 10 on which two dividers 36 are installed on a cylindrical winding axis 34 having a flange 32 on both ends and terminals 38 are provided at ends of the flanges and dividers, a primary winding wound around a center spool portion divided by both dividers, and two secondary windings wound around a side spool portion divided by flanges and dividers. In the center spool portion, two separators 44 are opposed in the center separated by a width of a winding wire rod, a winding advance direction is reversed for a left-side space and a right-side space by the separator pairs, and a winding state is made to be symmetrical about the center. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a two-output type inverter transformer in which a primary winding is located in the center and secondary windings are located on both sides thereof. More specifically, the present invention relates to a central winding portion around which a primary winding is wound. Two separators are placed in the center so that the winding direction of the innermost layer of the primary winding is outward from the center on the left and right of the separator pair by the separator pair, and the primary winding is centered on the center. The present invention relates to a symmetrical inverter transformer. This inverter transformer is useful for a discharge tube lighting circuit for a backlight of a liquid crystal TV, for example.

  As is well known, a liquid crystal TV uses a discharge tube (cold cathode tube) as a backlight of a liquid crystal panel. In recent years, the number of discharge tubes used for backlights has increased remarkably due to the increase in size of liquid crystal panels. Specifically, 20 discharge tubes are used for 40-inch panels and 24 discharge tubes are used for 46-inch panels. For this reason, the cost of the inverter transformer used for lighting the discharge tube, the increase in the mounting area, and the increase in the size of the mounting board are problems. As a countermeasure, the inverter transformer is mainly a two-output type.

  In a two-output type inverter transformer, a symmetrical form in which the secondary winding is positioned on both sides of the primary winding is employed in order to make the electrical characteristics of the two secondary windings uniform (for example, Patent Document 1). reference). However, depending on the winding state of the primary winding (such as the positional relationship between the primary winding and both secondary windings), considerable variation occurs in the leakage inductance of the two secondary windings.

  Therefore, it has been proposed to use a bobbin having a structure in which a separator is provided at the center of the central winding frame and the primary winding is divided and wound. An example of such a bobbin structure is shown in FIG. The bobbin 10 has a structure in which two partition plates 16 are installed on a cylindrical winding shaft 14 having flanges 12 at both ends, and terminals 18 are provided at end portions of the flange 12 and the partition plate 16. The primary winding is wound around the central winding frame portion 20 defined by both partition plates 16 of the bobbin 10, and two side winding frame portions 22 defined by the flange 12 and the partition plate 16 are respectively provided with 2 pieces. The next winding is wound. Here, the central winding frame portion 20 around which the primary winding is wound is provided with one separator 24 at the center, and the primary winding is divided into two parts by the separator 24 and wound.

  FIG. 4B shows an example in which the primary winding P is wound in three layers and the outermost layer is unwinding. The primary winding starts from the left end of the left space. That is, in the left space, as indicated by the arrow, the winding direction of the innermost layer goes from the left end to the center, the winding direction of the second layer returns from the center to the left end, and the outermost layer (third layer) is the winding direction. Goes from the left to the center. Next, move to the right space. In the right space, the innermost layer turns from the center to the right end, the second layer returns the winding direction from the right end to the center, and the outermost layer (third layer) is centered on the winding direction. Head to the right end.

In this winding structure, winding the half of the primary winding in the left space and winding the other half in the right space improves the balance of the winding state in the left and right spaces, and leakage of the secondary winding The variation in inductance can be suppressed to some extent. However, even in such a winding structure, when the primary winding is wound in multiple layers, if there is a surplus winding in the outermost layer as described above, the winding state in both the left and right spaces is closer to the left side (or Both are on the right). Therefore, since the winding state is not symmetrical with respect to the center, there is a certain limit to the effect of suppressing variation in leakage inductance of the secondary winding. For example, when only half the outermost layer is wound, a deviation of about 3% occurs in the leakage inductance of the two secondary windings. Therefore, measures such as evenly winding the outermost layer with space are taken, but there are significant disadvantages in terms of man-hours and management.
JP 2006-165063 A

  The problem to be solved by the present invention is that in a two-output type inverter transformer in which the secondary winding is located on both sides of the primary winding, a special winding such as a space winding when an excess winding occurs in the outermost layer. It is possible to reduce variation in leakage inductance of the two secondary windings without performing management.

  The present invention has a structure in which two partition plates are installed on a magnetic core that forms a closed magnetic path, and a cylindrical winding shaft having flanges at both ends, and terminals are provided at the ends of the flange and the partition plate. A bobbin and a primary winding wound around a central winding frame section defined by both partition plates of the bobbin and two two windings wound around both side winding frame sections defined by a flange and a partition plate In the two-output type inverter transformer provided with the secondary winding, the central winding frame portion around which the primary winding is wound has two separators opposed to each other with the width of the winding wire in the center, The winding direction of the primary winding is reversed between the left space and right space of the separator pair by the separator pair, and the winding state in the left space and right space is symmetrical with respect to the center. This is an inverter transformer.

  Here, a boss for routing the primary winding wire protrudes from the partition plate of the central winding portion around which the primary winding is wound, and the primary winding wire is hooked on the boss so that the terminal is entangled. The primary winding wire is guided to the central winding frame, and further, the transition groove for delivering the primary winding wire from the vicinity of the partition plate boss to the separator on the bobbin winding surface. Is preferably provided.

  In the inverter transformer according to the present invention, two separators are placed in the center part of the central winding frame portion around which the primary winding is wound, with the winding wire material arranged in a width, and the winding wire material is disposed between the separator pair. Since the winding travel direction of the primary winding is reversed on the left and right sides of the separator pair, the winding state is left and right with respect to the center in the left and right spaces of the separator pair. Can be symmetric. Therefore, even if the outermost layer has extra windings and is wound densely, the winding state of the left space and the right space is symmetrical with respect to the center, and variation in leakage inductance of the secondary winding is minimized. Can be suppressed.

  FIG. 1 is an explanatory diagram showing a typical example of an inverter transformer according to the present invention. A represents the plane of the bobbin, B represents the cross section of the main part, and C represents the plane of the assembled inverter transformer.

  The bobbin 30 has a structure in which two partition plates 36 are installed on a cylindrical winding shaft 34 having flanges 32 at both ends, and terminals 38 are provided at end portions of the flange 32 and the partition plate 36. The primary winding P is wound around the central winding frame portion 40 partitioned by both partition plates 36 of the bobbin 30, and two side winding frame portions 42 partitioned by the flange 32 and the partition plate 36 are respectively 2 The next windings S1 and S2 are wound. In the present invention, in the central winding frame portion 40 around which the primary winding is wound, two separators 44 are arranged at the center portion with a width (interval larger than the wire diameter) as the winding wire, The winding direction of the primary winding is reversed on the left and right of the separator pair by the separator pair, which is characteristic in this respect.

  FIG. 1B shows an example in which the primary winding P is wound in three layers and the outermost layer is unwinding. In the present invention, the winding is started after passing the primary winding between the two separators 44 provided at the center. Therefore, in the left space of the separator pair, the winding direction is from the center to the left end in the innermost layer, the winding direction returns from the left end to the center in the second layer, and the winding direction is the center in the outermost layer (third layer). Head to the far left. In the right space of the separator pair, the winding direction is from the center to the right end in the innermost layer, the winding direction returns from the right end to the center in the second layer, and the winding direction is from the center to the right end in the outermost layer (third layer). Head to. Therefore, the respective winding states in the left space and right space of the central winding frame portion are symmetrical with respect to the center even if a winding remainder occurs in the outermost layer.

  A set of magnetic cores forming a closed magnetic path is a combination of a square frame core made of, for example, ferrite and a rod-shaped core having a rectangular cross section. In the example shown in FIG. 1C, the rod-shaped core 46 is inserted into the winding shaft of the bobbin 10, and the square frame-shaped core 48 is disposed on the outer periphery of the bobbin 10, thereby forming a combined closed magnetic path in a Japanese character shape. It has become so. Instead of the combination of the rectangular frame core and the rod-shaped core, a structure in which two E-shaped cores are combined so that the middle leg portions thereof are inserted into the winding shaft and the end surfaces are brought into contact with each other may be used.

  In the bobbin structure as shown in FIG. 4B (hereinafter referred to as a comparative example), if there is a surplus winding in the outermost layer, the winding state becomes asymmetrical between the left and right sides of the separator, and variations occur in the leakage inductance of the secondary winding. . For example, when only half the outermost layer is wound, a deviation of about 3% occurs in the leakage inductance of the two secondary windings. However, in the present invention, as shown in FIG. 1B, the winding state of the primary winding is bilaterally symmetrical. Therefore, even if special winding management such as space winding of the outermost layer is not performed, 2 The variation in the leakage inductance of the secondary winding can be suppressed to within 1%.

  FIG. 2 is an explanatory view showing an embodiment of the bobbin of the inverter transformer according to the present invention. A represents a plane, B represents a side surface, C represents a bottom surface, and D represents an xx cross section of A.

  The bobbin 50 has a structure in which two partition plates 56 are installed on a square cylindrical winding shaft 54 having flanges 52 at both ends, and terminals 58 are provided at end portions of the flange 52 and the partition plate 56. . The central winding frame portion 60 for primary winding is defined by both partition plates 56 of the bobbin 50, and two side winding frame portions 62 for secondary winding are defined by the flange 52 and the partition plate 56. Is done.

  Here, in the central winding frame portion 60 around which the primary winding is wound, two separators 64 are opposed to each other at the central portion with a width (interval larger than the wire diameter) as the primary winding wire. . Further, a boss 66 for routing the primary winding wire is projected from the partition plate 56, and further, a transition groove for delivering the primary winding to the winding shaft 54 from the vicinity of the boss of the partition plate 56 to the separator 64. 68 is provided.

  The boss 66 has a function of bending the passage of the primary winding wire and guiding it to the central winding frame by hooking the primary winding wire on the boss 66, and the transition groove 68 is bent by the boss 66. The primary winding wire is routed between the separators 64, and at the same time, the winding wire is buried in the winding shaft 54 so as not to be thickened. Further, the two separators 64 at the center define the winding start position of the primary winding.

  In addition, a plurality of (four each here) separators are provided in the side winding frame portion around which the secondary winding is wound, and the separator is divided into five spaces, which divide the high-voltage secondary winding. It is for winding up and improving electrical insulation performance.

  The winding sequence of the primary winding is shown in FIG. The winding work is performed in the order of A → B → C → D. The primary winding wire entangled with the terminal 58 is drawn in the order between the boss 66 → the transition groove 68 → the two separators 64, and then winding is started (see A). First, in the left space, the innermost layer is wound from the center toward the left (see B), and then the left end is wound toward the center. If the necessary number of turns (1/2 of the number of turns of the primary winding) is reached by repeating this process, it is returned between the two separators 64 at the center (see C). Next, in the right space, winding is performed from the center toward the right as the innermost layer, and then from the right end toward the center. When the necessary number of turns (1/2 of the number of turns of the primary winding) is reached by repeating this, it is hooked and pulled out by the boss 66 and led to the terminal 58 (see D).

  Since the secondary winding generates a high voltage, but the flowing current is small, a single wire (called a thin wire) of a polyurethane-coated wire having a wire diameter of 0.1 mm or less (for example, a copper wire diameter of about 0.03 to 0.04 mm) is used. ) Is used. The secondary winding is dividedly wound around the side winding frame portion into a winding space partitioned by a separator a predetermined number of times. Each winding end is soldered while being tangled to the terminal. Soldering is performed by dipping (immersing) in molten solder.

  Table 1 shows the actual measurement results of the product of the present invention and the comparative example. For the primary winding, a thick wire with a wire diameter of 0.25 mm is used and the number of turns is 54. For the secondary winding, a single wire with a wire diameter of φ0.03 mm is used and the number of turns is 2800 times (each winding of 5 sections). 560 windings per space: gap 0.1 mm). In addition, the outermost layer of the primary winding is in a state of 1/2 winding remainder (wound to half each of the left space and the right space). Ten samples each of the product of the present invention and the comparative example were measured, and the average value thereof was determined.

本発明品でも比較例でも、２つの２次巻線のインダクタンスについては、殆ど差は生じていない。しかし、漏れインダクタンスに関しては、比較例では、２つの２次巻線でかなりのばらつきが発生している。それに対して本発明品では、漏れインダクタンスにおいても、２つの２次巻線で殆ど差が生じていないことが分かる。これらの実測結果から、本発明は、２次巻線の漏れインダクタンスのばらつきを低減する上で、極めて有用であることが実証された。

In the product of the present invention and the comparative example, there is almost no difference in inductance between the two secondary windings. However, with respect to the leakage inductance, in the comparative example, considerable variation occurs between the two secondary windings. On the other hand, in the product of the present invention, it can be seen that there is almost no difference in leakage inductance between the two secondary windings. From these actual measurement results, it was proved that the present invention is extremely useful in reducing the variation in the leakage inductance of the secondary winding.

Explanatory drawing which shows the typical example of the inverter transformer which concerns on this invention. Explanatory drawing which shows one Example of a bobbin structure. Explanatory drawing which shows the winding order. Explanatory drawing which shows the comparative example of the bobbin structure of an inverter transformer, and a primary winding.

Explanation of symbols

30 Bobbin 32 Flange 34 Winding shaft 36 Partition plate 38 Terminal 40 Central reel portion 42 Side reel portion 44 Separator

Claims (3)

A magnetic core that forms a closed magnetic path; a bobbin having a structure in which two partition plates are installed on a cylindrical winding shaft having flanges at both ends; and terminals are provided at ends of the flange and the partition plate; A primary winding wound around a central winding frame section defined by both partition plates of a bobbin and two secondary windings wound around both side winding section sections defined by a flange and a partition plate In the two-output type inverter transformer provided,
In the center winding frame portion around which the primary winding is wound, two separators are placed in the center portion with a width corresponding to the winding wire, and the winding direction of the primary winding is separated by the separator pair. An inverter transformer characterized in that the left space and right space of the pair are reversed and the winding state in the left space and right space is symmetrical with respect to the center.   A boss for routing the primary winding wire protrudes from the partition plate of the central winding frame portion around which the primary winding is wound, and the primary winding entangled with the terminal by hooking the primary winding wire to the boss The inverter transformer according to claim 1, wherein the winding wire is guided to the central winding frame.   The inverter transformer according to claim 2, wherein a transition groove for delivering the primary winding wire material is provided on the surface of the bobbin winding shaft from the vicinity of the boss of the partition plate to the separator.

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