JP2008147358A - Isolation transformer - Google Patents

Abstract

An insulating distance of a safety standard can be satisfied even with a simple structure, so that it can be manufactured at a low cost and a structure suitable for downsizing and thinning can be realized.
A bobbin 10 in which a cylindrical winding body 20 and winding frame parts 22 and 26 and a terminal holding part 24 are integrated, and a primary coil 12 and a secondary coil 14 wound around the winding body. And an insulating transformer comprising a magnetic core that forms a closed magnetic path between the inside and the outside of the winding drum section. The magnetic core is, for example, a combination of an I-type core 40 and a mouth-type core 42, or an I-type core and a C-type core. A primary coil is wound in the center of the bobbin body of the bobbin, and secondary coils are wound on both sides thereof, and the winding of the magnetic core located outside of the body of the body to which these windings are applied. A magnetic core portion facing the body portion is covered with an insulating material 44.
[Selection] Figure 1

Description

  The present invention relates to an insulating transformer used for various inverter devices and the like. More specifically, without storing the bobbin in an insulating case, the winding position of the primary coil and the partial insulation treatment of the magnetic core The present invention relates to an insulation transformer that can satisfy a safety standard insulation distance with a simple structure.

  Insulation transformers used in power supplies for industrial equipment and various inverters must be designed and manufactured to meet the safety standards of countries around the world. Therefore, in general, the insulation distance between the primary coil or the secondary coil and the magnetic core is secured by housing the bobbin with windings inside the insulation case (see, for example, Patent Document 1). .

However, in these transformers, since the shape of the magnetic core and bobbin is complicated, the insulating case to be used needs to have a complicated structure accordingly. This complicates the design of the insulation distance (creeping distance). For example, when combining E-type cores, an insulating case is also required in the middle leg portion of the E-type core. Since the structure of the insulating case is complicated as described above, the manufacturing cost increases. In addition, the use of an insulating case increases the size of the transformer and causes a significant problem particularly when attempting to reduce the thickness.
JP 2002-141229 A

  The problem to be solved by the present invention is that it can satisfy the insulation distance (creeping distance) of the safety standard while having a simple structure, so that it can be manufactured at a low cost and is suitable for downsizing and thinning. Is to be able to do it.

  The present invention includes a bobbin in which a cylindrical winding body part, a winding frame part, and a terminal holding part are integrated, a primary coil and a secondary coil wound around the winding body part, and winding. In a transformer having a magnetic core that forms a closed magnetic path between the inside and outside of the winding body, a primary coil is wound around the center of the winding body of the bobbin, and secondary coils are wound on both sides thereof. It is an insulated transformer in which the magnetic core portion facing the winding drum portion of the magnetic core positioned outside the winding drum portion on which the windings are provided is covered with an insulating material.

  For example, the magnetic core is composed of a combination of an I-type core inserted into the winding body and a mouth-shaped core (rectangular frame core) surrounding the outside of the winding body, and is parallel to the I-type core of the mouth-shaped core. The two sides are covered with an insulating material. Alternatively, the magnetic core is composed of a combination of an I-type core inserted inside the winding drum part and a C-type core positioned outside the winding drum part, and one side parallel to the I-type core of the C-type core is The structure is covered with an insulating material. The magnetic core is not limited to the above shape, and may be a combination of two E-type cores, for example.

  The insulating material is, for example, an insulating tape, and the insulating tape has a structure in which a plurality of turns are wound around the entire predetermined side of the mouth-shaped core or the C-shaped core. Alternatively, the insulating material is an elongated resin cover having a U-shaped cross section, and the resin cover is fitted to a predetermined side of the mouth-shaped core or the C-shaped core outward from the side facing the winding body portion. It may be a structure.

  In the insulation transformer according to the present invention, the magnetic core portion of the magnetic core located outside the winding drum portion is covered with an insulating material, and the primary coil is located in the center, and 2 on each side thereof. Since the secondary coil is located, the creeping distance between the primary coil and the magnetic core can be increased by the length of the secondary coil being wound. Therefore, the magnetic core can be designed as a secondary structure, and the design of the insulation distance that satisfies the safety standard can be simplified. Further, in the present invention, an insulating case having a complicated structure is unnecessary, so that not only the manufacturing cost can be reduced, but also the size and thickness can be reduced.

  If a combination of an I-type core and a C-type core (a shape obtained by cutting off one side of the mouth-shaped core) is used as the magnetic core, the size can be further reduced as compared with the case of using a combination of the I-type core and the mouth-shaped core. Also, there is an effect that the work of winding the insulating tape can be easily performed. Further, when an elongated resin cover having a U-shaped cross section is used as the insulating material, it can be easily attached not only to the C-type core but also to the mouth-type core, thereby improving workability.

  FIG. 1 is an assembly explanatory view showing an embodiment of an insulating transformer according to the present invention. FIG. 2 is an explanatory view of the assembly, in which A represents a plane and B represents an xx section thereof. The insulating transformer shown in this embodiment is a surface mount type inverter transformer.

  As shown in FIG. 1, the insulating transformer includes a bobbin 10 in which a cylindrical winding drum portion, a winding frame portion, and a terminal holding portion are integrated, a primary coil 12 wound around the winding drum portion, and A secondary coil 14 and a magnetic core that forms a closed magnetic path between the inside and the outside of the winding body portion on which the winding is provided are provided.

  The bobbin 10 includes a cylindrical winding body portion 20, end side winding frame portions 22 are located at both ends of the winding body portion 20, and a terminal holding portion 24 is continuous with the end side winding frame portion 22. An intermediate winding frame portion 26 is provided at two intermediate portions of the winding drum portion 20 and is continuous so that the terminal holding portion 24 projects outwardly, and these are integrally molded with resin. One or more terminals 28 protrude from the holding portion 24. Here, the winding body 20 has a rectangular tube shape into which a part of the magnetic core is inserted. The upper surfaces of the terminal holding portions 24 at both end portions are grooves 30 having a rectangular cross section so as to accommodate a part of the magnetic core, and a magnetic core positioning stopper 32 is formed on one of the grooves. Each terminal 28 protrudes from the terminal holding part 24 in the vertical and horizontal direction with respect to the winding body part 20. Note that the winding terminals are not connected to all of the numerous terminals, and some are used only for mounting on the mounting board.

  The primary coil 12 and the secondary coil 14 are wound around the winding body portion 20, and the intermediate winding frame portion 26 defines the winding region of the primary coil 12 and the secondary coil 14. In the present invention, the central portion sandwiched between the two intermediate winding frame portions 26 becomes the winding region of the primary coil 12, and the two side portions sandwiched between the intermediate winding frame portion 26 and the end-side winding frame portion 22 are This is a winding region of the secondary coil 14. Here, the winding region of the secondary coil 14 is further divided into five small winding regions by four separators 34. The ends of the primary coil 12 and the secondary coil 14 wound around the winding body 20 are connected to the corresponding terminals 28 by soldering. Thus, in this invention, the primary coil 12 is arrange | positioned in the center of the winding trunk | drum 20 of the bobbin 10, and the secondary coil 14 is arrange | positioned at the both sides, respectively, and it is one of the indispensable requirements. is there.

  Here, the magnetic core is composed of a combination of an I-type core 40 inserted into the inside of the winding body 20 and a mouth-shaped core (rectangular frame core) 42 surrounding the outside of the winding body 20. The I-type core 40 has a quadrangular cross section and is a size that can be inserted into the winding body 20, and is slightly shorter than the axial length of the bobbin 10. The mouth-shaped core 24 has an outer dimension that is approximately the same as the outer shape of the bobbin main body (excluding the terminal), and has an inner dimension that can surround the winding body portion that has been wound. By combining the two ends of the I-shaped core 40 so that the two sides of the mouth-shaped core 42 overlap each other, two closed magnetic paths are formed between the inside and the outside of the winding body portion on which the winding is applied. Note that most of the mouth core 42 substantially matches the thickness of the I core 40, but the bottom side of the mouth core 42 that overlaps both ends of the I core 40 is designed to have a thin bottom surface. Has been. In the present invention, the two sides of the mouth-shaped core 42 parallel to the I-type core 40 are covered with the insulating material 44. The insulating material 44 may be, for example, an insulating tape, and has a structure in which the insulating tape is wound around a predetermined side of the mouth core 42 for three or more turns.

  Thus, if the part facing the said winding drum part of the mouth-shaped core 42 located outside the winding drum part 20 is covered with an insulating material, the secondary coils 14 are located on both sides of the central primary coil 12 respectively. Therefore, the primary coil 12 and the mouth-shaped core 42 are equal to the sum of the length of the winding of the secondary coil 14 and the width of the winding frame portion located in the middle (this is indicated by the symbol L). A creepage distance can be secured. Therefore, a necessary insulation distance between the primary coil 12 and the secondary coil 14 can be secured, and the mouth core 42 can be handled as a secondary structure, so that a simple insulation design is possible. .

  The magnetic core used in the present invention may be a combination of an I-type core 40 and a C-type core 46 as shown in FIG. A is a plan view and B is a yy sectional view. Here, the C-shaped core 46 has a shape in which one side of the mouth-shaped core used in the above embodiment is cut off. The structure of the bobbin, the winding positions of the primary coil and the secondary coil, and the like may be the same as those in the above-described embodiment, and thus illustration and description thereof are omitted. The I-type core 40 is inserted into the bobbin winding body, and the C-type core 46 is located outside the winding body. The entire side parallel to the I-type core 40 of the C-type core 46 is covered with an insulating material 44. The insulating material may be, for example, an insulating tape, and has a structure in which the insulating tape is wound around a predetermined side of the C-type core 46 for three or more turns. By combining the opposite ends of the I-type core 40 so that the two opposite sides of the C-type core 46 overlap each other, one closed magnetic path is formed between the inside and the outside of the winding body portion on which the winding is applied. Note that the two sides of the C-type core 46 overlapping the both ends of the I-type core 40 are designed to be thin with a part on the lower surface side as shown in FIG. 3B. The C-type core 46 can be further reduced in size and weight due to the lack of one side of the mouth-type core, and the insulating tape can be easily wound.

  As shown in FIG. 4, the insulating material applied to the magnetic core may be an elongated resin cover 48 having a U-shaped cross section. Such a resin cover 48 is fitted to the middle side of the C-shaped core 46 outward from the inner side (side facing the winding body). The mounting of the resin cover 46 is easier to work than the winding of the insulating tape, and has an advantage that it can be easily applied even to a mouth-shaped core.

  The magnetic core is not limited to the above shape, and may be a combination of two E-type cores, for example. If the resin cover has a U-shaped cross section and has an elongated shape as described above, the insulating material can be easily attached.

Assembly explanatory drawing which shows one Example of the insulation transformer which concerns on this invention. Explanatory drawing of the assembly. Explanatory drawing which shows the other example of a magnetic core. Explanatory drawing which shows the other example of an insulating material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bobbin 12 Primary coil 14 Secondary coil 20 Winding drum part 22 End side reel part 24 Terminal holding part 26 Intermediate reel part 28 Terminal 40 I type core 42 Mouth type core 44 Insulating material

Claims (5)

A bobbin in which a cylindrical winding drum portion, a winding frame portion, and a terminal holding portion are integrated, a primary coil and a secondary coil wound around the winding drum portion, and a winding drum portion provided with windings In a transformer having a magnetic core that forms a closed magnetic circuit between the inside and the outside of
A primary coil is wound around the center of the bobbin body of the bobbin, and secondary coils are wound on both sides of the primary coil. An insulating transformer, wherein a magnetic core portion facing a winding drum portion is covered with an insulating material.   The magnetic core is composed of a combination of an I-type core inserted into the inside of the winding drum portion and a mouth-shaped core surrounding the outside of the winding drum portion, and two sides parallel to the I-type core of the mouth-shaped core are insulating materials. The insulation transformer according to claim 1, wherein the insulation transformer is covered.   The magnetic core is composed of a combination of an I-type core inserted into the winding body and a C-type core positioned outside the winding body, and one side parallel to the I-type core of the C-type core is an insulating material. The insulating transformer according to claim 1, which is covered with   The insulating transformer according to claim 2 or 3, wherein the insulating material is an insulating tape, and the insulating tape is wound a plurality of turns around a predetermined side of the mouth-shaped core or the C-shaped core.   The insulating material is an elongated resin cover having a U-shaped cross section, and the resin cover is fitted outwardly from a side facing the winding body portion on a predetermined side of the mouth-shaped core or the C-shaped core. Item 4. The insulation transformer according to Item 2 or 3.

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