KR20080001836U - Transformer - Google Patents

Abstract

By efficiently adjusting the mutual inductance between the coils, an appropriate coupling coefficient (k) can be obtained, and a transformer capable of equally stabilizing the current flowing through the coil is provided.

A main core wound by a plurality of coils adjacent to each other, the cross-sectional area of which is smaller than the cross-sectional area of the main core, and moves relative to the main core so as to change mutual inductance generated between the adjacent coils, and interposed between the adjacent coils. It is set as the structure comprised by combining the arranged sub core.

Description

Transformers

The present invention relates to a boost transformer for lighting a discharge tube.

In backlight lighting of many liquid crystal display devices, a cold cathode fluorescent lamp (CCFL) or an EEFL is used as a main light source.

Since a high voltage is required for the lighting of discharge tubes, such as a cold cathode fluorescent tube, an inverter circuit is generally used. In the past, one boost transformer was used for one lamp of these discharge tubes.

By the way, a large number of discharge tubes have been used for a large surface light source such as a liquid crystal television display, and the inverter circuit has been complicated because one boost transformer and a driving circuit are required for each discharge tube when the discharge tubes are turned on.

However, in recent years, the backlight for liquid crystal displays has been further enlarged to use very many discharge tubes. Therefore, these surface light source inverter circuits are turning into lighting a some discharge tube simultaneously with one transformer.

17 is a perspective view of an example of a conventional four-light boost transformer. The transformer 400 is a combination of two U-shaped cores 41 and 41, each of which extends and protrudes two leg portions at right angles from both ends of the abdomen, in a K-shaped closed shape. use. One opposing leg is inserted into the hollow hole of the bobbin 40 wound around the primary coil 401, and the other leg is inserted into the hollow hole of the bobbin 40 wound around the secondary coils 402 and 402. Insert it. 18 is a circuit configuration diagram when this transformer is connected to a discharge tube. When the discharge tube is connected to the second stage of each of the secondary coils 402 and 402 and a voltage is applied to the primary coil 401, magnetic flux is generated, and a high voltage is generated to the secondary coils 402 and 402. The discharge tube is turned on.

In the example of the transformer 400, when the coupling coefficient k between the two secondary coils 402 and 402 is high, the cold cathode tubes are connected to each other as in the parallel equivalent circuit of FIGS. 19 to 20. The effect occurs. As shown in FIG. 20, the output current I is the sum of the load current I ₁ and (I ₂ ) or (I ₃ ) and (I ₄ ), which are divided into discharge tubes, respectively. Since the discharge tube has a negative impedance characteristic, when one tube current increases, a current of the other side decreases.

This phenomenon occurs because the coupling coefficient between the first secondary coil 402 and the second secondary coil 402 is high, that is, they share a main magnetic flux.

In this way, sharing the main magnetic flux causes an unbalance in the tube currents of the respective discharge tubes, so that the respective discharge tubes cannot be turned on stably at the same time.

On the other hand, to solve this, lowering the coupling coefficient (k) also lowers the coupling between the primary coil 401 and the secondary coils 402 and 402, resulting in more inductive components seen from the primary coil side. Since the power factor seen from the primary coil side is lowered, a large amount of reactive current flows in the primary coil, resulting in a large amount of copper loss and heat generation. This leads to lower conversion efficiency of the lighting circuit and lower limit of power that can be supplied.

In addition, if the coupling coefficient between the primary coil and the secondary coil is too high, there is a problem that the self resonant frequency of the secondary coil is too low. If the self-resonant frequency is lower than the drive frequency of the inverter circuit, the tube current is unbalanced, and sufficient boost is impossible, thereby generating more heat.

An object of the present invention is to provide a transformer capable of efficiently obtaining a condition in which the balance of tube current is optimal by adjusting mutual inductance between coils.

In order to achieve the above object, the present invention provides a main core wound with a plurality of coils adjacent to each other, the cross-sectional area of which is smaller than the cross-sectional area of the main core, and moves relative to the main core to change mutual inductances generated between the adjacent coils. In addition, to provide a transformer, characterized in that the combination made of the sub-cores interposed between the adjacent coils.

In addition, by increasing the cross-sectional area of one end of the core farther from the sub core of the main core than that of other parts of the main core, the coupling coefficient between the primary coil and the secondary coil farther from the sub core is maintained.

In the transformer, the sub core is moved so as to change a gap between the main core and the main core so that the bottom surface of the sub core contacts the main core.

In the transformer, the sub-core is covered with a U-shaped cover in cross section.

In the transformer, the bottom surface of the sub core can be moved so as to change the gap between the main core without contacting the main core with the sub core as an axis.

The sub-cores may be arranged so that the two sub-cores are arranged in a straight line with a gap therebetween, and the gap between the two sub-cores may be adjusted to change the relative position of the main core and the sub-cores. .

Moreover, in the said trans | transformer, it can be made to pass through the said passage of the edge member which formed the passage so that the said sub core may not contact with the said main core.

The said edge member is a cylindrical case form as an example.

The tubular case is divided into two parts, a first case member and a second case member each having a plurality of orthogonal parts engaged with each other, and the first case member and the second case member communicate with each other so as to communicate with each other. It is also possible to form a coaxial passageway through the sub core.

As another example, the rim member has two vertical cross-sections with the sub-core as an axis, and each of the two vertical cross-sections drills a shaft hole as the passage, and the sub-cores have the form of a screw rod. It can also be inserted through the shaft hole.

Two sidewalls in the passage of the edge member may be formed to protrude so that the guide member which guides when the sub core is moved back and forth in the passage slightly contacts the sub core.

An elastic member is provided at one end of the passage to contact the sub core to press the sub core to elastically press, and at the other end, a control member for contacting the sub core to stop at another desired position against the elastic pressing force. You can do that.

The control member has a screw perpendicular to the main core, the head of the screw being a flat head and a position in contact with the sub-core while allowing the head to be eccentric with respect to an irregular shape or thread. It may be.

Further, a gap in the vertical direction may be provided between the leading end of the sub core and the main core.

The lifting member is, for example, a pad attached to a lower portion of the sub core.

As the lifting member, as another example, a roller having an eccentric shaft is used.

As another example of the elevating member, the elevating member may be composed of an elastic member for pressing one end of the sub-core to be positioned, and a clamp with a screw rod for raising and lowering the other end.

As said transformer, as an example, it can be set as the structure which winds a primary coil in the both ends of the both ends which inserted one end of the said main core near the said sub core, and winds a secondary coil in the other end, respectively.

As the transformer, as another example, a configuration in which a secondary coil is wound around each of two opposite portions of the main core that face the sub core, and a primary coil is wound around each of the two opposite portions of the main core, respectively You can also do

As said transformer, as another example, the primary coil may be wound around the end of each of the main cores in which the sub cores are sandwiched, and the secondary coil may be wound around the opposite end of the main core.

As said primary coil, it is preferable to wind with one coil.

As a cross sectional area of the said sub core, it is preferable to set it as 1/2 or less of the effective cross sectional area of the said main core.

Moreover, it is preferable that the cross sectional area near the sub core of the said main core is below the effective cross sectional area of the said main core.

According to the method of the present invention, by using the main core and a sub core having a cross-sectional area smaller than that of the main core, the mutual inductance generated between the secondary coils is lowered, so that the coupling coefficient between the primary coil and the secondary coil is increased. In addition, by adjusting the relative position between the sub core and the main core so that the self-resonance frequency of the secondary coil is not too low, it is easy to find a condition in which the tube current is well balanced, moderately low leakage inductance, high output and low heat generation are achieved. Can be.

Moreover, the transformer mass-produced based on the positional relationship determined by the said adjustment method is a thing of balance of tube current well, high output, low heat generation, and small size.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. It is to be noted that components having the same configuration and function are denoted by the same reference numerals and description thereof will be omitted.

1 is a cross-sectional view of a transformer of an embodiment of the present invention. 2 is an exploded perspective view of FIG. 1.

The transformer 100 is a main core 11 that combines two U-shaped cores 110 and 110, each of which extends and protrudes two leg portions at right angles from both ends of the abdomen, in a K-shaped closed shape. ). Two legs of each of the two c-shaped cores 110 and 110 are cut and tapered from one side, and each one leg is bobbin 115 wound with, for example, the primary coils 111 and 111. Bobbins 116 and 116 inserted into the hollow holes of the 115 and 115, and wound around the secondary coils 112 and 112 as a plurality of coils 10 and 10, respectively, with different leg portions. Insert it into the hollow hole. The two U-shaped cores 110 and 110 are wound on the two U-shaped cores 110 so that the primary coils 111 and 111 and the secondary coils 112 and 112 are connected in series. The rod-shaped sub-cores 12 are disposed to face each other, in combination with the U-shaped main cores 11 in the shape of a substantially Japanese-like shape over the two leg portions of the two c-shaped cores 110. Is done. Here, the major axis direction of the rod-shaped sub core 12 is X direction.

In the transformer 100 of the present invention, the main core 11 combined in a U-shape and its effective cross sectional area 121 are subcores 12 whose effective cross sectional area 113 is less than or equal to the effective cross sectional area 113 of the c-shaped core 110. Use

In this example, the effective cross sectional area 121 of the sub-core 12 is less than or equal to the effective cross sectional area 113 of the U-shaped core 110, but the core that is less than one half of the effective cross sectional area 113 is sub The core 12 may be used. Moreover, the core whose effective cross sectional area 113 near the sub core 12 of the main core 11 is below the effective cross sectional area 114 near the abdomen of the c-shaped core 110 is preferable.

Subsequently, the sub core 12 is brought close to the main core 11 and interposed between the secondary coils 112 and 112 of the main core 11. In this example, the sub-cores 12 are covered with the cover edges 13 where the legs of the U-shaped cores 110 and 110 face each other, and the contact area 122 is formed in the edges 13. The sub core 12 is disposed in contact with the main core 11 in a movable manner. By moving the sub core 12 with respect to the main core 11 along the X direction, the magnetic fluxes forming mutual inductances of the secondary coils 112 and 112 are split, and the magnetic flux of the coils 110 and 110 is broken down. The relative position between the main core 11 and the sub core 12 is adjusted to form this effective dividing path.

At this time, if the main core and the sub-core are completely in contact with each other, the self-resonant frequency of the secondary coil may be too low. Therefore, the self-resonant frequency of the secondary coil is measured, and the self-resonant frequency is approximately at least that of the inverter circuit. Adjust the position so that it is not less than 1.5 times the operating frequency.

Subsequently, the sub core 12 is fixed on the main core 11 by an adhesive or the like.

By using the sub core 12 to adjust the mutual inductance between the adjacent coils 10 so as to satisfy the following Equation 1, it is possible to improve the excitation flux due to mutual inductance between the adjacent coils.

 [Equation 1]

     Length of magnetic circuit = physical distance of magnetic flux / cross-sectional area of core

From the above, by adjusting the surface area of the main core 11 and the sub core 12 and effectively shortening the magnetic circuit, the influence of mutual inductance can be reduced, and if the magnetic circuit is effectively lengthened, the secondary coil Since the magnetic resonance frequency of can be made high, by adjusting this, a transformer having an optimum magnetic flux configuration can be obtained. As a result, the current flowing through the discharge tube can be equally stabilized, and the leakage inductance can be reduced to achieve a high output transformer.

In addition, since the present invention has a configuration in which the cross-sectional area 114 of a part far from the sub core 12 of the main core 11 is set to be equal to or greater than the effective cross-sectional area 113 of the main core 11, each 1 The lengths of the effective magnetic circuits of adjacent secondary coils 112 and 112 are shortened by the difference coils 111 and 111 via this 114. As a result, the coupling near 114 of the secondary coil becomes relatively close to the other end, i.e., the sub core side, and the secondary coils 112 and 112 near the sub core 12 are formed. ), Since the coupling decreases and becomes a small coupling, the traveling wave entering the secondary coil from the sub-core can be reduced so that the standing wave can be reduced. As a result, there is little heat generation, and a large output transformer can be achieved.

In the said transformer, although the sub-core 12 contacted the main core 11 and made it contact, it was set as the structure of the small and mill coupling, but the sub-core 12 does not contact the main core 11, but was made. It is good also as a structure which does not.

That is, it is good also as a structure which makes it move so that the bottom face of the sub core 12 may change the gap between the main core 11, without contacting the main core 11, with the sub core 12 as an axis. As an example, in this transformer, an edge member having a passage formed therein is inserted into the passage of the cylindrical case member 33 so that the sub core 12 does not contact the main core 11.

3 is a perspective view of a transformer of another embodiment of the present invention. This transformer is different from the above embodiment in that the sub-core 12 is not installed in contact with the main core 11, and the sub-core 12 penetrates into the square tube 33 to form a gap 123. Let it be installed configuration. In this transformer, the gap 123 is provided without bringing the sub core 12 into contact with the main core 11 so that the two cores 11 of the main core 11 are parallel to the abdomen of each of the c-shaped cores 110 and 110. It is set as the structure to install over a leg part. Here, the several adjacent coils 10 and 10 are connected in series through the external circuit 20 formed on the printed wiring board. By changing the gap 123 between the sub core 12 and the main core 11 by moving the sub core 12 back and forth in the X direction, the mutual inductance of adjacent coils can be adjusted to the maximum. Therefore, as in the above embodiment, since the optimum small-mill coupling configuration can be easily found, the gap 123 is changed to be a high-output, low-heating transformer and eliminate the influence of mutual inductance between adjacent coils. Thus, the current flowing through the discharge tube can be stabilized in the same manner.

4 is a perspective view of a transformer of another embodiment of the present invention. This transformer differs from the above embodiment in that the adjacent cores 10 and 10 are brought closer to the main core 11 with each tube 33 penetrating the sub core 12 to form the facing area 124. The structure is arranged between them. As in the above embodiment, it has a high output and low heat generation transformer, and has the effect of stabilizing the current equally.

5 is a plan view of a transformer of another embodiment of the present invention. This transformer differs from the above embodiment in that the sub cores 12 are arranged so that the two sub cores 12a and 12b are arranged in a line with a gap D therebetween. It is also possible to adjust the relative positions of the main core 11 and the sub core 12 by adjusting the gap D between the two sub cores 12a and 12b.

6 is an exploded perspective view of a transformer of another embodiment of the present invention. FIG. 7 is an assembled perspective view of the transformer of FIG. 6. FIG. In this transformer, the cylindrical case 33 is orthogonal parts 331a, 332a, 331b, 332b,... The first case member 331 and the second case member 332 which are formed in plural numbers are divided into two, and the bobbins 31 and 32 respectively cover the first case member 331 and the second case member 332. Coaxial passages 334 are formed in communication with each other to penetrate the subcore 12.

8 is a perspective view of a transformer of another embodiment of the present invention. Unlike the above example, the edge member 33 has a groove shape having a predetermined height as another example, and has two vertical cross-sections 33a and 33b with the sub core 12 as an axis in the groove. Drill the shaft holes 334a and 334b in each of the vertical cross-sections 33a and 33b, and the sub-cores 12 form a threaded rod so that they can be inserted into two shaft holes 334a and 334b. do.

9 is a perspective view of a transformer of another embodiment of the present invention. Unlike the above example, the two side walls 334c in the long groove-shaped passage 334 of the edge member 33 having a predetermined height are used to orient the guide when moving the sub core 12 back and forth within the passage 334. Guide members 161, 161,... Is formed into a protrusion and slightly contacts the sub core 12.

10 is a perspective view of a transformer of another embodiment of the present invention. An elastic member 162 contacting the sub core 12 at one end of the groove-shaped passage 334 to press the sub core 12 to elastically press, and the sub core 12 at the other end to oppose the elastic pressing force. The sub core 12 can be moved along the X direction by providing the control member 163 for stopping at another desired position.

In this example, the control member 163 is a screw 163a perpendicular to the main core 11, and the screw 163a is a flat head and is in contact with the sub core 12. , Head 163b is eccentric with respect to an irregular shape or screw 163a.

In the above example, the vertical height is made constant by using the edge member 334 having a predetermined height. However, the present invention is not limited thereto, and the sub core 12 is disposed between the distal end portion and the main core 11 in the vertical direction. It may also be made of a lifting member for adjusting the gap.

11 is a perspective view of a transformer of another embodiment of the present invention. In FIG. 11, as the elevating member for adjusting the height of the sub core 12 with respect to the main core 11, the pad 14 is attached to the lower portion of the sub core 12 in the edge member 33.

12, the roller 15 which has an eccentric shaft can also be used.

Moreover, as shown in FIG. 13, using the elevating member which consists of the positioning elastic member 162 which presses | positions one end of the sub core 12, and the clamp 163 with the screw rod which fits and lifts the other end of the sub core 12, and uses it. Also good.

14 is a plan view of a transformer of another embodiment of the present invention. As this transformer, the primary coils 111 and 111 are wound with one coil, respectively, on one of the two opposing portions of the main core 11 that face the sub core 12, and the two opposite sides of the main core 11 are wound. The secondary coils 112 and 112 are wound around the sections as a plurality of coils 10 and 10, respectively.

15 is a plan view of a transformer of another embodiment of the present invention. As the transformer, unlike the above example, the secondary coils 112 and 112 are connected to a plurality of adjacent coils 10 and 10 at the end portions near each of the sub cores 12 on which both of the sub cores 12 are fitted. The primary coils 111 and 111 are wound by one coil at one end on the opposite side thereof.

16 is a plan view of a transformer of another embodiment of the present invention. As this transformer, the primary coils 111 and 111 are connected to a plurality of adjacent coils 10, (at the ends of the main core 11 near the sub core 12 on both sides of the sub core 12, respectively. 10), the sub-cores are sandwiched and electrically wound with one coil, and the secondary coils 112 and 112 are wound around the opposite end thereof.

This winding of the primary coil is intended to better balance the current in the discharge vessel. Moreover, since only one coil is sufficient electrically, the meaning is the same even if it connects like this to 20 of FIGS. 3-4 by external wiring after connecting this to an external terminal once.

Each of the above-described transformers facilitates a configuration having an optimum small coupling / tight coupling by moving the sub core 12 relative to the main core 11 to adjust mutual inductance between the coils and the magnetic resonance frequency of the secondary coil. At the same time, the current flowing through the discharge tube can be equally stabilized.

From the above, since the sub core 12 is moved in the X direction with respect to the main core 11, the structure can be freely adjusted for mutual inductance of adjacent coils, so that the transformer is high in power and low in heat. The current flowing on the discharge tube can be equally stabilized.

While the present invention has been described with specific examples for the lighting use of the discharge tube for liquid crystal backlight as one of its embodiments, the mutual inductance adjusting method of the present invention can freely adjust the mutual inductance of adjacent coils, and has high output and low It is useful for various electric devices that require this because it generates heat and has the effect of uniformly stabilizing the current flowing on the windings.

1 is a cross-sectional view showing a transformer of one embodiment of the present invention.

Fig. 2 is a schematic exploded perspective view of the transformer of Fig. 1.

3 is a perspective view showing a transformer of another embodiment of the present invention.

4 is a perspective view showing a transformer of another embodiment of the present invention.

5 is a plan view illustrating a transformer of another embodiment of the present invention.

6 is an exploded perspective view showing a transformer of another embodiment of the present invention.

Fig. 7 is an assembled perspective view of the transformer of Fig. 6.

8 is a perspective view showing a transformer of another embodiment of the present invention.

9 is a perspective view showing a transformer of another embodiment of the present invention.

10 is a perspective view showing a transformer of another embodiment of the present invention.

11 is a cross-sectional view showing a transformer of another embodiment of the present invention.

12 is a cross-sectional view showing a transformer of another embodiment of the present invention.

13 is a perspective view showing a transformer of another embodiment of the present invention.

14 is a plan view showing a transformer of another embodiment of the present invention.

15 is a plan view illustrating a transformer of another embodiment of the present invention.

FIG. 16 is a plan view illustrating a transformer of another embodiment of the present invention. FIG.

Fig. 17 is a plan view of a conventional trans example.

Fig. 18 is a circuit configuration diagram using the transformer of Fig. 17.

FIG. 19 is an equivalent circuit of FIG. 18.

FIG. 20 is a circuit diagram for describing a current flow method of a discharge tube in the circuit of FIG. 19. FIG.

[Description of the code]

100 ... trans

10 ... adjacent coils

11,110 ... main core

111 ... primary coil

112 ... secondary coil

113,114,121,122,124 ... area

115,116,31,32 ... bobbin

12,12a, 12b ... sub core

123 ... gap

13 ... Borders

161 ... guide member

162.Elastic member

163 control element

163a ... screw

163 b ... head

20.External circuit

33.Border member (cylindrical case member)

33a, 33b ...

331a, 332a, 331b, 332b ...

331,332 ... Case member

334 ... passage

334a, 334b ... shaft hole

334c ... side walls

Claims (23)

A main core wound by a plurality of coils adjacent to each other, the cross-sectional area thereof being smaller than the cross-sectional area of the main core, and moving relative to the main core so as to change mutual inductance occurring between the adjacent coils, interposed between the adjacent coils. A transformer comprising the sub-cores arranged so as to be combined. The transformer according to claim 1, wherein the sub core is moved so as to change a gap between the main core and the main core over the main core so that the bottom surface of the sub core is in contact with the main core. 3. The transformer according to claim 2, wherein the sub core is covered with a U-shaped cover in cross section. The transformer of claim 1, wherein the bottom of the sub core is movable to change a gap between the main core without contacting the main core. The transformer according to claim 4, wherein the sub core is inserted into the passage of an edge member having a passage formed therein so as not to contact the main core. 6. The transformer according to claim 5, wherein the frame member is in the form of a cylindrical case. According to claim 6, The cylindrical case is divided into two, the first case member and the second case member formed with a plurality of orthogonal parts which are engaged with each other, respectively, and the first case member and the second case member in communication with each other And a coaxial passageway through the sub core. 6. The frame member according to claim 5, wherein the edge member has two vertical cross sections with the sub core as an axis, and each of the two vertical cross sections drills a shaft hole as the passage. The sub-core is in the form of a screw rod, the transformer characterized in that the insertion through the two shaft holes. 6. The transformer according to claim 5, wherein a guide member for guiding said sub-core when moving said sub core back and forth in said passage is formed in two side walls in said passage of said edge member so as to contact said sub core slightly. 6. An elastic member according to claim 5, wherein said elastic member presses said sub core to one end of said passage to press and press said sub core, and the other end contacts said sub core to stop at another desired position against said elastic pressing force. A transformer, characterized in that it is provided with a control member to make it. The screw of claim 10, wherein the control member has a screw perpendicular to the main core, the head of which is a flat head, and the head is in an irregular shape or screw while being in contact with the sub core. And eccentric to the trans. The gap between the two sub-cores according to claim 1, wherein the sub-cores are arranged so that the two sub-cores are arranged in a straight line with a gap, and the relative positions of the main cores and the sub-cores are adjusted. A transformer, characterized in that for adjusting. The transformer according to claim 1, further comprising a lifting member for adjusting a gap in a vertical direction between the leading end of the sub core and the main core. The transformer according to claim 13, wherein the elevating member is a pad attached to a lower portion of the sub core. The transformer according to claim 13, wherein the elevating member is a roller having an eccentric shaft. The transformer according to claim 13, wherein the elevating member comprises an elastic member for pressing and positioning one end of the sub core, and a clamp with a screw rod for raising and lowering the other end. The transformer according to claim 1, wherein a primary coil is wound around one end of each of the main cores sandwiched near the sub core, and a secondary coil is wound around the other end as the plurality of coils. The method of claim 1, wherein a secondary coil is wound as the plurality of adjacent coils at ends of each of the main cores adjacent to the sub core, respectively, on both sides of the sub core, and the primary coil is wound at one end opposite to the main core. Trans characterized in that the. The method according to claim 1, wherein the primary coil is wound around the main core as the plurality of adjacent coils at the ends near each of the subcores on both sides of the main core, and the secondary coil is wound at an end opposite to the main core. The trance characterized by. 20. The transformer according to any one of claims 17 to 19, wherein the primary coil is wound with a coil electrically connected to one wire over the sub core. The transformer according to claim 1, wherein the transverse cross-sectional area of the sub core is set to be 1/2 or less of the effective cross-sectional area of the main core. The transformer according to claim 1, wherein the cross sectional area near the sub core of the main core is equal to or less than the effective cross sectional area of the main core. The transformer according to claim 1, wherein a cross-sectional area of a part far from the sub core of the main core is equal to or greater than an effective cross sectional area of the main core.

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