JP2009026915A - Transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transformer which can have improved insulation between a primary coil and a second coil with a core interposed therebetween with a simple structure without making an outward shape large in size, and then can securely have a requested insulation distance. <P>SOLUTION: In the transformer wherein a first bobbin 1 wound with the primary coil 3 and a second bobbin 2 wound with a secondary coil 9 are disposed adjacently and a closed magnetic path is formed by the core arranged across the first and second bobbins, the core is divided into a first core 17 disposed on the side of the first bobbin and a second core 18 disposed on the side of the second bobbin, and an insulating member 14 having outer periphery covering portions 16a and 16b each covering an outer periphery of at least one of the first and second cores and a partition portion 15 interposed between opposite surfaces of the both is interposed between magnetic joint portions of the first and second cores 17 and 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transformer suitable for use in a device that generates a high voltage from a secondary coil such as an inverter transformer for lighting a cold cathode tube.

In general, various transformers adopt a structure that ensures a predetermined insulation distance (creeping distance) between a primary coil and a secondary coil in accordance with safety standard requirements.
On the other hand, an inverter transformer for discharging and lighting a cold cathode tube incorporated as a light source of a liquid crystal display boosts the input voltage to the primary coil to a high voltage of 1000 to 2000 V in the secondary coil, and the cold cathode tube described above. Is output.

For this reason, it is required to secure a longer insulation distance between the primary coil and the secondary coil to ensure insulation between them compared to a general low-voltage transformer.
However, in this type of high-voltage generating transformer, even when insulation between the primary coil and the secondary coil is secured, the core that forms a closed magnetic circuit around these coils is not an insulator. Therefore, there is a problem that desired insulation performance cannot be obtained through the core.

  Therefore, for example, in Patent Document 1 below, a through hole is formed in the center portion, a bobbin in which a primary coil and a secondary coil are wound around an outer peripheral portion, and a part of the bobbin is inserted into the through hole, In a transformer comprising a pair of core members that are brought together outside the through hole, an insulating member is provided between at least one of the pair of core members and the through hole of the bobbin. A transformer has been proposed.

According to the transformer having the above configuration, since the insulating member is provided between at least one of the pair of core members and the through hole of the bobbin, the pair of core members, the primary coil, and 2 There is an advantage that the creepage distance with the next coil can be extended.
JP 2002-141229 A

  However, in the transformer found in Patent Document 1, it is necessary to provide an insulating member between the bobbin through-hole and the entire length of at least one core member in order to obtain a desired effect. For example, when the core member is an E-type core, there is a problem that the shape and structure of the insulating member are complicated.

  In addition, since the insulating member is provided between the core member and the through hole, it is necessary to make the through hole of the bobbin larger than the conventional one. There was a problem of going against the request for downsizing.

  The present invention has been made in view of such circumstances, and can improve the insulation between the primary coil and the secondary coil via the core with a simple structure without causing an increase in the size of the outer shape. Therefore, it is an object of the present invention to provide a transformer that can ensure the required insulation distance.

  The present invention separates a core forming a closed magnetic circuit into a first core adjacent to the primary coil side and a second core adjacent to the secondary coil side, and the first core is the first bobbin. And the second core as a secondary part together with the second bobbin, and by applying a predetermined insulation treatment between the magnetic joints of the first and second cores. It is to secure a desired insulation distance between the primary part and the secondary part.

  That is, in the first aspect of the invention, the first bobbin in which the primary coil is wound around the first winding portion and the second coil in which the secondary coil is wound around the second winding portion. In a transformer in which a bobbin is disposed adjacent to each other and a closed magnetic path is formed by a core made of a magnetic material disposed across the first and second bobbins, the core is connected to the first bobbin. The first core located on the bobbin side and the second core located on the second bobbin side are divided, and the first and second cores are separated between the magnetic joints of the first and second cores. An insulating member having an outer periphery covering portion covering the outer periphery of at least one of the two cores and a partition wall portion interposed between the opposing surfaces of the two cores is interposed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first and second bobbins are disposed adjacent to each other in the axial direction, and the first and second bobbins are arranged. A pair of outer cores each extending in the axial direction along the outer periphery of the first or second bobbin, and the first or second windings positioned in the middle of the outer cores. An inner core inserted into the portion, and the insulating member is interposed between the first and second outer cores, and the first winding portion and the second winding. A second partition wall interposed between the opposing surfaces of the inner core is formed between the first and second surfaces.

  Further, the invention according to claim 3 is the invention according to claim 1 or 2, in which one of the first winding portion and the second winding portion is provided at the other end of the first winding portion. An insulating covering portion is formed to cover the outer periphery of the next coil or the two coils.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the insulating member is integrally formed on an outer periphery of the insulating coating portion.

  According to the transformer according to any one of claims 1 to 4, the cores are positioned on the first bobbin side and are positioned on the first bobbin side and on the second bobbin side. The first core is divided into a second core that is a secondary part, and an insulating member having electrical insulation is interposed between the magnetic joints of the first and second cores. An insulation distance corresponding to the length dimension of the outer peripheral covering portion of the insulating member can be ensured between the first core and the second core.

  As a result, it is possible to improve the insulation between the primary coil and the secondary coil via the core with a simple structure, and therefore, it is required between the primary coil and the secondary coil with certainty. An insulation distance can be secured.

  When the first and second cores have an outer core and an inner core, respectively, the first winding into which the inner core is inserted as in the invention described in claim 2. If a second partition wall interposed between the facing surfaces of these inner cores is formed between the first core and the second winding part, between the outer cores of the first core and the second core, The insulation distance corresponding to the length dimension of the outer peripheral covering portion of the insulating member described above can be ensured. Moreover, between the inner cores, an insulation distance corresponding to the length dimension in the axial direction of the first winding portion or the second winding portion can be ensured.

  Here, the thickness dimension of the partition wall portion and the second partition wall portion of the insulating member is a gap between the opposing surfaces of the first and second cores. The gap is the same as that of the first and second cores. It is necessary to secure predetermined magnetic connection characteristics while achieving electrical insulation. From this viewpoint, it is preferable that the thickness dimension of the partition wall serving as the gap is set in a range of 1.0 to 0.4 mm.

  Further, as in the invention described in claim 3, the insulating coating that covers the outer periphery of the other primary coil or the two coils at one end of either the first winding portion or the second winding portion. If the first and second bobbins are arranged adjacent to each other, an insulation distance corresponding to the length dimension of the insulation coating portion can be secured between the two coils even when the first and second bobbins are arranged adjacent to each other. Can be achieved.

  In addition, if the insulating member is integrally formed on the outer periphery of the insulating coating portion as in the invention described in claim 4, the insulating member is injected into the first winding portion or the second winding portion. When molding, it can be molded at the same time and is easy to manufacture, and the number of parts as a whole transformer can be reduced.

(First embodiment)
FIGS. 1 to 7 show a first embodiment in which the transformer according to the present invention is applied to an inverter transformer for lighting a cold cathode tube serving as a backlight of an LCD, and a modification thereof. In this inverter transformer, The bobbin is divided into a first bobbin 1 and a second bobbin 2.

  As shown in FIG. 2, the first bobbin 1 is a rectangular tube-shaped first coil around which a primary coil 3 (see FIGS. 1 and 5B) formed in the central portion in the axial direction is wound. Of the first winding part 4 and a terminal 5 formed on one end side in the axial direction of the first winding part 4 to which the end part of the primary coil 3 is connected. The terminal mounting portion 6 and the insulating covering portion 7 formed on the other end side in the axial direction of the first winding portion 4 are integrally formed of a synthetic resin having electrical insulation.

  The insulation coating portion 7 is formed in a rectangular tube shape that is slightly larger in width and thickness than the first winding portion 4, and the insulation coating portion 7, the first winding portion 4, In between, the partition part (2nd partition part) 8 which interrupts | blocks a mutual internal space is shape | molded integrally. Here, the thickness dimension of the axial direction of the partition part 8 is set to the range of 1.0-0.4 mm.

  As a result, the first winding portion 4 has an inner space that opens to the first terminal mounting portion 6 side, and an inner wall surface 4 a that is flat and continuous with the surface 6 a of the first terminal mounting portion 6. Is formed. The insulation coating portion 7 is formed such that the length dimension in the axial direction is the same as or slightly larger than the length dimension in the axial direction of the second winding portion 10 described later of the second bobbin 2.

  On the other hand, as shown in FIG. 3, the second bobbin 2 includes a second winding portion 10 having a rectangular tube shape around which a secondary coil 9 (see FIGS. 1 and 5B) is wound, Similarly, the second terminal mounting portion 12 having a flat plate shape in which the terminal 11 that is arranged on one end side in the axial direction of the second winding portion 10 and to which the end portion of the secondary coil 9 is connected is implanted is also electrically connected. It is integrally formed of an insulating synthetic resin.

  In the second winding portion 10, a plurality of partition plates 13 for preventing creeping discharge in the high-voltage secondary coil 9 are integrally formed on the outer peripheral portion at equal intervals in the axial direction. The external dimensions of the plate 13 are formed slightly smaller than the internal dimensions of the insulating coating portion 7 in the first bobbin 1. Further, the second winding portion 10 is formed so that the inner space thereof opens to the second terminal mounting portion 12 side, and the inner wall surface 10a is continuously continuous with the surface 12a of the second terminal mounting portion 12. Has been.

  As shown in FIG. 5, the second bobbin 2 is wound with the secondary coil 9 (the secondary coil 9 is not shown in FIG. 5A). Is integrally connected to the first bobbin 1 by being inserted into the insulating coating portion 7 of the first bobbin 1.

  Further, as shown in FIG. 6, cover members (insulating members) 14 are respectively arranged on both sides in the axial direction of the first and second bobbins 1 and 2. As shown in FIG. 4, the cover member 14 is formed in a rectangular tube shape that is open at both ends by an electrically insulating synthetic resin, and a partition wall 15 is formed inside. Here, the thickness dimension in the axial direction of the partition wall 15 is set in a range of 1.0 to 0.4 mm.

  In addition, the partition wall 15 has a length L1 of a first cylindrical portion (outer peripheral covering portion) 16a formed from the partition wall 15 to one end portion in the axial direction of the first winding portion 4. The length L2 of the second cylindrical portion (outer peripheral covering portion) 16b formed up to the other end portion is approximately equal to the length dimension of the second winding portion 10 (or the insulating covering portion 7). Is formed at a position that is substantially equal to the length dimension in the axial direction.

  As shown in FIGS. 1 and 6, the first and second bobbins 1 and 2 are provided with cores configured by the first and second cores 17 and 18 to form a closed magnetic circuit. . Each of the first and second cores 17 and 18 includes a pair of outer cores 17a and 18a extending in the axial direction along the outer periphery of the first bobbin 1 or the second bobbin 2, and the outer cores 17a and 18a. This is an E-type core having inner cores 17b and 18b located in the middle part of the.

  The outer core 17 a and the inner core 17 b of the first core 17 are formed to have a length dimension substantially equal to the length dimension in the axial direction of the first winding portion 4, and the outer core of the second core 18. 18a and the inner core 18b are formed in the length dimension substantially equal to the length dimension of the axial direction of the 2nd coil | winding part 10 (or insulation coating part 7).

As shown in FIG. 6, in the first core 17, the outer core 17 a is inserted into the first cylindrical portion 16 a of the cover member 14, and the inner core 17 b is the first winding portion 4. It is attached by being inserted into the internal space.
On the other hand, as for the 2nd core 18, while the outer core 18a is each inserted in the 2nd cylindrical part 16b of the cover member 14, the inner core 18 is inserted in the internal space of the 2nd coil | winding part 10. FIG. It is attached by.

  In the transformer configured as described above, the outer cores 17a and 18a of the first and second cores 17 and 18 are respectively connected to the first and second cylindrical portions 16a and 16b of the cover member 14 having electrical insulation. And the inner cores 17b and 18b are respectively inserted into the first winding part 4 or the second winding part 10 and between the opposing faces. Since the partition wall 15 is provided, the first core 17 and the second core 18 can be electrically insulated from each other.

  Furthermore, an insulation distance corresponding to the length dimension (L1 + L2) of the first and second cylindrical portions 16a, 16b of the cover member 14 shown in FIG. 4 can be secured between the outer cores 17a, 18a. . Moreover, also between the inner cores 17b and 18b, the insulation distance corresponding to the length dimension (X + Y) of the axial direction of the 1st coil | winding part 4 and the insulation coating part 7 shown in FIG. 2 is securable.

  In addition, since the insulation coating portion 7 that covers the outer periphery of the second coil 9 is formed at the end of the first winding portion 4, insulation is also provided between the primary coil 3 and the secondary coil 9. An insulation distance corresponding to the length dimension Y of the covering portion 7 can be ensured.

  Thus, according to the above transformer, the core constituting the closed magnetic circuit is located on the first bobbin 1 side and is located on the first bobbin 2 side and the first core 17 serving as the primary part. The secondary coil 18 is divided into the second core 18 which is the secondary part, and the primary coil via the core is formed by a simple structure because the two are electrically insulated and a sufficient insulation distance is secured. Insulating properties between the primary coil 3 and the secondary coil 9 can be improved, so that the required insulation distance between the primary coil 3 and the secondary coil 9 can be ensured.

  In addition, the thickness of the partition wall 15 of the cover member 14 and the partition wall 8 formed between the first winding portion 4 and the insulating coating portion 7 is set in the range of 1.0 to 0.4 mm. Therefore, it is possible to ensure the predetermined magnetic connection characteristics while achieving the electrical insulation of the first core 17 and the second core 18.

  In the first embodiment, the length of the inner and outer cores 17a and 17b of the first core 17 is shorter than the length of the inner and outer cores 18a and 18b of the second core 18. As a result, a case has been described in which the partition wall portion 15 of the cover member 14 is formed at a position where the length dimension L1 of the first tubular portion 16a <the length dimension L2 of the second tubular portion 16a. However, it is not limited to this.

  That is, as shown in FIG. 7A, the first cylindrical portion 22a and the second cylindrical portion 22b have the same length dimension by forming the partition wall portion 21 in the center in the longitudinal direction. A member (insulating member) 20 can also be used.

  Further, when the required insulation distance is relatively short, as shown in FIG. 7B, it has a cylindrical portion 24 into which only the outer core of one of the cores is inserted, and the cylindrical shape It is also possible to use a cover member (insulating member) 23 in which the partition wall portion 25 is integrally formed at the end of the portion 24.

(Second Embodiment)
8 to 10 show a second embodiment of a transformer according to the present invention. The same components as those shown in FIGS. 1 to 6 are denoted by the same reference numerals and the description thereof is simplified. To do.
The difference of this transformer from that shown in the first embodiment is that a cover member (insulating member) 30 is integrally formed on the outer periphery of the insulating coating portion 7 in the first bobbin 1.

  That is, the both sides in the axial direction of the insulating coating portion 7 have the same cross-sectional shape as the cover member 14 shown in the first embodiment, and have the same length in the axial direction as the insulating coating portion 7. A cover member 30 is formed. Moreover, in this cover member 30, one cylindrical part (outer periphery covering part) opened to the 2nd bobbin 2 side by forming the partition part 31 in the edge part by the side of the 1st winding part 4 side. 32 only.

  As shown in FIG. 9, in the second core 18, the outer core 18 a is inserted into the cylindrical portion 32 of the cover member 30, and the inner core 18 is the internal space of the second winding portion 10. It is attached by being inserted into. In contrast, in the first core 17, the inner core 17 b is inserted into the inner space of the first winding portion 4, and the front end surface of the outer core 17 a is abutted against the outer surface of the partition wall portion 31 of the cover member 30. It is attached in contact.

  Even with the transformer configured as described above, it is possible to obtain the same effects as those shown in the first embodiment. In addition, in this transformer, since the cover member 30 is integrally formed on the outer periphery of the insulating coating portion 7, together with the first winding portion 4, the first terminal mounting portion 6 and the insulating coating portion 7, The cover member 30 can be injection molded at the same time. As a result, the manufacture is further facilitated, and the number of parts as a whole transformer can be reduced.

  In each of the first and second embodiments, only when the insulating cover members 14, 20, 23, 30 having a cylindrical portion and a partition wall are used as the insulating member. Although described, the present invention is not limited to this, and an outer periphery covering portion that covers the outer periphery of at least one of the outer cores 17a and 18a, and a partition wall portion interposed between opposing surfaces of the outer cores 17a and 18a, An insulating member integrally formed by molding with a synthetic resin can also be used.

  Further, the insulating member having the outer peripheral covering portion and the partition wall portion may be configured by other methods such as covering at least one of the outer cores 17a and 18a with a heat shrinkable tube or winding an insulating tape. Is possible.

  Further, the first and second cores 17 and 18 are not limited to the E-type core having the outer cores 17a and 18a and the inner cores 17b and 18b described above. For example, the C-type having only a pair of outer cores. An E-type core as a whole may be used by further arranging an I-type core between the core and the central part of the C-type core. In these cases, a transformer having the same function is configured. It is possible.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a first embodiment of a transformer according to the present invention, in which (a) is a plan view of the whole, (b) is a right side view, and (c) is a sectional view taken along line cc of (a). . FIG. 2 shows a first bobbin before being wound by the primary coil of FIG. 1, wherein (a) is a sectional view taken along line aa of (c), (b) is a plan view, and (c) is a front view. FIG. 4D is a sectional view taken along line dd in FIG. The 2nd bobbin before the secondary coil of FIG. 1 is wound is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. 1A and 1B show a cover member of FIG. 1, in which FIG. 1A is a front view, FIG. 1B is a plan view, FIG. 1C is a cross-sectional view taken along the line cc of FIG. It is a figure which shows the assembly state of the 1st and 2nd bobbin, (a) is a top view, (b) is a longitudinal cross-sectional view after an assembly. It is a top view which shows the assembly state of the 1st and 2nd core and a cover member. It is sectional drawing which shows the modification of the cover member of FIG. It is a figure which shows the assembly state of the 1st and 2nd bobbin in 2nd Embodiment of the trans | transformer which concerns on this invention, and is the top view which looked at the 1st bobbin in cross section. It is a top view which shows the assembly state of the 1st and 2nd core in 2nd Embodiment. It is a top view which shows the whole transformer of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st bobbin 2 2nd bobbin 3 Primary coil 7 Insulation coating | cover part 8 Partition part (2nd partition part)
9 Secondary coil 10 Second winding part 14, 20, 23, 30 Cover member (insulating member)
15, 21, 25, 31 Partition part 16a, 22a First cylindrical part (outer peripheral covering part)
16b, 22b 2nd cylindrical part (outer periphery coating | coated part)
17 1st core 18 2nd core 17a, 18a Outer core 17b, 18b Inner core 24, 32 Cylindrical part (outer periphery coating | coated part)

Claims (4)

A first bobbin in which a primary coil is wound around the first winding part and a second bobbin in which a secondary coil is wound around the second winding part are arranged adjacent to each other; In a transformer in which a closed magnetic circuit is formed by a core made of a magnetic material disposed across the first and second bobbins,
The core is divided into a first core located on the first bobbin side and a second core located on the second bobbin side, and a magnetic joint portion of these first and second cores An insulating member having an outer periphery covering portion covering at least one outer periphery of the first and second cores and a partition wall portion interposed between the opposing surfaces of the first and second cores is interposed therebetween. Transformer.   The first and second bobbins are disposed adjacent to each other in the axial direction, and the first and second cores are respectively arranged along the outer circumference of the first or second bobbin. A pair of outer cores extending in the direction, and an inner core that is located in an intermediate portion between the outer cores and is inserted into the first or second winding portion, and the first and second cores. The insulating member is interposed between the two outer cores, and a second interposed between the opposing surfaces of the inner core between the first winding portion and the second winding portion. The transformer according to claim 1, wherein a partition wall is formed.   An insulating coating covering the outer periphery of the other primary coil or two coils is formed at one end of either the first winding portion or the second winding portion. The transformer according to claim 1 or 2.   The transformer according to claim 3, wherein the insulating member is integrally formed on an outer periphery of the insulating coating portion.

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