JP2015135846A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer that can be easily produced with high accuracy so that it can be automatically mounted on a circuit board, while easily and reliably securing creepage distances between a secondary-side coil and a primary-side coil and between the secondary-side coil and a core.SOLUTION: A transformer comprises a secondary-side coil assembly 1 that has a secondary-side coil of a strip metal formed in an opened annular cylindrical shape, a mounted terminal 7 formed of the secondary-side coil bent at both ends so that their plane surfaces are positioned on the same plane, and a first bobbin 5 made of an insulative resin integrally formed around the whole circumference of the secondary-side coil; a primary-side coil assembly 2 that is formed of a primary-side coil 2b wound around the whole circumference of a second bobbin 2a and arranged in an internal space of the secondary-side coil assembly 1; and a core 3 that surrounds an outer periphery of the secondary-side coil assembly 1 and the primary-side coil assembly 2 to form a closed magnetic circuit.

Description

  The present invention relates to a transformer used as a power transformer or the like in which a large current flows in a secondary coil.

  In a transformer in which a large current of 100 A or more flows in a secondary coil, such as a power transformer for a vehicle, the above-mentioned large current is usually obtained by using a metal flat plate having a small resistance value as the coil. We are dealing with it.

  By the way, when the coil is made of a metal flat plate, the secondary coil and the primary coil cannot be made into a layer winding structure. However, depending on the structure, coupling is poor and it is difficult to obtain desired characteristics.

Therefore, a transformer has also been proposed in which a secondary coil is formed by bending a strip-shaped copper plate into an arc shape, and this is coaxially disposed on the outer periphery of the primary coil.
However, when such a transformer is surface-mounted on a substrate, the end of the coil is usually joined to a mounting terminal provided in advance on the transformer by soldering or welding, but the secondary coil has a strip shape. Therefore, there arises a problem that it is difficult to couple this to a mounting terminal provided in the transformer.

  For this reason, a configuration in which both ends of the secondary coil are bent to form mounting terminals and directly joined to the land portion of the board is conceivable. However, since the secondary coil is a single component, It is difficult to ensure the flatness of the mounting terminals due to the mounting accuracy and deformation at the time of mounting, and there is a problem that skill in surface mounting work is required.

In addition, since it is difficult to obtain surface mounting accuracy at the mounting terminals, it has been an obstacle to automatic mounting. Further, since the secondary coil is exposed to the outside as a single component, there is a problem that it is difficult to ensure a creeping distance from the primary coil and the core.
Incidentally, a power transformer using a ring-shaped coil made of a metal flat plate as a secondary coil corresponding to the same large current is disclosed in, for example, Patent Document 1 below.

JP 2001-267153 A

  The present invention has been made in view of the above circumstances, and can be easily manufactured with high accuracy. Therefore, automatic mounting on a substrate can be achieved, and a secondary coil, a primary coil, and It is an object of the present invention to provide a transformer that can easily and reliably ensure a creepage distance from a core.

  In order to solve the above-mentioned problem, a transformer according to the present invention described in claim 1 is a secondary coil formed by forming a strip-shaped metal into a ring-opened cylindrical shape, and both end portions thereof are on the same plane. A secondary coil assembly in which a first bobbin made of an insulating resin is integrally formed on the entire circumference of the secondary coil, and an outer periphery of the second bobbin A primary side coil assembly disposed in the inner space of the secondary side coil assembly, and surroundings the outer periphery of the secondary side coil assembly and the primary side coil assembly. And a core that forms a closed magnetic path.

  According to a second aspect of the present invention, in the first aspect of the present invention, the secondary coil is formed in a U shape bent in an out-of-plane direction, and the second coil is inserted into the entire circumference by insert molding. By forming one bobbin integrally, the secondary coil assembly is formed in a gate shape having a top plate and a pair of side plates, and the primary coil is formed in a rectangular tube shape, and the secondary coil assembly The cores are inserted into the top plate and the side plates of the side coil assembly, and the core is composed of a pair of opposed E-shaped cores, and the middle legs are inserted into the primary side coil, An outer leg is disposed along the side plate of the secondary coil assembly.

  Furthermore, the invention according to claim 3 is the position of the invention according to claim 1 or 2, wherein the side plate of the secondary coil assembly is positioned away from the position where the E-type core faces the outer leg. In addition, a hole is formed in which a part of the secondary coil is exposed due to the support member of the secondary coil at the time of the insert molding, and a hook-like shape is formed between the hole and the core. Insulating portions that protrude are formed.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein an end of the primary coil is connected to the first bobbin of the secondary coil assembly. The terminal mounting part provided with the mounting terminal is integrally formed.

  According to the invention of any one of claims 1 to 4, the entire circumference of the ring-opening cylindrical secondary coil made of a strip-shaped metal is covered with the first bobbin made of an insulating resin and integrated. Since the secondary coil assembly is used, the secondary coil assembly can be easily assembled with the primary coil assembly and the core. In addition, since both end portions of the secondary coil are bent to form mounting terminals whose respective plate surfaces are located on the same plane, mounting on the substrate is facilitated.

  Moreover, in the secondary side coil assembly, since the entire circumference of the secondary side coil is covered with the insulating resin, it is easy to ensure a creepage distance from the primary side coil and the core.

  In particular, according to the invention described in claim 2, since the first bobbin is integrally formed by insert molding on the entire circumference of the secondary coil formed in a U shape, In addition to being able to correct the shape of the secondary side coil and its mounting terminals in the mold, the secondary side coil and the first bobbin are integrated after the molding, thereby providing high strength 2 A secondary coil assembly can be obtained. Therefore, the secondary coil assembly can be manufactured with high accuracy, and automatic mounting can be easily realized.

  When the first bobbin is integrally formed around the entire circumference of the secondary coil by insert molding as in the invention described in claim 2, the secondary coil is previously pinned to a predetermined position of the cavity of the mold. In a state of being held by a support member such as the above, the insulating resin is injected around the periphery of the secondary coil to cast a secondary coil. For this reason, in the obtained secondary side coil assembly, after removing the said pin, the hole part which an internal secondary side coil exposes will be formed. On the other hand, since the outer legs of the E-shaped core are disposed on the side plate of the secondary coil, if the hole is formed in the vicinity of the outer legs, the creepage between the secondary coil and the core It may be difficult to secure the distance.

  In this regard, according to the third aspect of the present invention, the position of the support member that supports the side surface of the secondary coil at the time of insert molding is set to a position that deviates from the position facing the core, and 2 Since a side wall of the secondary coil assembly is formed with an insulating portion protruding in a bowl shape from between the hole and the core, the creepage distance between the secondary coil and the core exposed from the hole is also , Can be ensured reliably.

  Furthermore, according to the invention described in claim 4, the terminal mounting portion including the mounting terminal to which the end of the primary side coil is connected is integrally formed on the first bobbin of the secondary side coil assembly. Therefore, the mounting terminals of the secondary side coil and the primary side coil are integrally positioned in the secondary side coil assembly. Thereby, automatic mounting of the transformer on the substrate can be easily realized.

1 is an overall perspective view showing an embodiment of the present invention. 1A and 1B show a transformer of FIG. 1, in which FIG. 1A is a plan view, FIG. 1B is a front view, and FIG. FIG. 2 is an exploded perspective view of FIG. 1. The terminal mounting part of FIG. 1 and a secondary side coil assembly are shown, (a) is a top view, (b) is a front view, (c) is a bottom view. FIG. 5 is a cross-sectional view taken along line BB in FIG.

  1 to 5 show an embodiment of a transformer according to the present invention. The transformer includes a secondary side coil assembly 1, a primary side coil assembly 2, and secondary side coil assemblies 1 and 1 shown in FIGS. This is generally composed of a pair of E-type cores 3 surrounding the outer periphery of the secondary coil assembly 2 and forming a closed magnetic path.

  The secondary coil assembly 1 is composed of a secondary coil 4 formed by bending a strip-shaped copper plate, and a first bobbin 5 made of an insulating resin covering the entire circumference of the secondary coil 4. The primary coil assembly 2 has a primary coil 2b wound around the outer periphery of a square cylindrical second bobbin 2a and an insulating tape 2c wound around the outer periphery of the primary coil 2b. It is. A terminal block 6 is formed integrally with the first bobbin 5 of the secondary coil assembly 1.

  Here, the secondary side coil 4 is formed in a U shape by bending the copper plate in the out-of-plane direction, and at both ends thereof, the mutual plate surfaces are positioned on the same plane. The mounting terminals 7 bent outward by 90 ° are integrally formed.

  And as shown in FIG. 5, the said 1st bobbin 5 and the terminal block 6 are integrally molded by insert molding so that this secondary side coil 4 may be cast. Thereby, the 1st bobbin 5 which covers the perimeter of the secondary side coil 4 is formed in the gate type | mold which has the top plate 5a and a pair of side plate 5b according to the shape of the secondary side coil 4, The mounting terminal 7 of the secondary coil 4 is drawn out outward from the lower end of the side plate 5b in the drawing.

  Further, the terminal block 6 is formed in an annular shape so as to cover the outer periphery of the lower end portion of the side plate 5b of the first bobbin 5 in the figure. An opening 6c is formed to extend in the vertical direction. Terminal mounting portions 6a and 6b are formed on two sides of the terminal block 6 perpendicular to the side plate 5b of the first bobbin 5, and the primary side of the primary coil assembly 2 is formed on one terminal mounting portion 6a. A plurality of (four in the figure) mounting terminals 8 to which the end portions of the side coil 2b are joined are provided.

  For this reason, on the bottom surface of the terminal mounting portion 6a, as shown in FIGS. 2 (c) and 4 (c), 2 for guiding the end portion drawn from the primary coil 2b to the mounting terminal 8 is provided. A groove 9 of the strip is formed. The other terminal mounting portion 6b is provided with a plurality of (five in the figure) joining terminals 10 for mounting the transformer on the substrate. The mounting terminal 8 and the joining terminal 10 are both provided by being inserted into the terminal block 6 when the secondary coil 4 is insert-molded into the first bobbin 5.

  Further, when the secondary coil assembly 1 is manufactured by insert molding, the insulating coil is injected after the secondary coil 4 is previously installed in the cavity of the injection mold by a support member such as a pin. The periphery of the secondary coil 4 is filled. For this reason, the insulating resin is not covered at the position where the support member of the secondary coil 4 is in contact.

  For this reason, in the transformer of this embodiment, as a result of supporting the secondary coil 4 from the top, bottom, left and right during insert molding, the first bobbin 5 of the molded secondary coil assembly 1 has a ceiling. Holes 11 through which a part of the internal secondary coil 4 is exposed are formed at two locations on the outer surface of the plate 5a, one location on the back surface of the top plate 5 and one location on the upper outer surface of both side plates 5b. ing. And the insulating part 12 is integrally formed in the circumference | surroundings of the hole part 11 formed in the upper outer surface of the both-sides version 5b.

  The insulating portion 12 includes a flat plate-like flange portion 12a protruding along the edge portion of the hole portion 11 on the terminal block 6 side, and from both ends of the flange portion 12a to the top plate 5a along both side edges of the hole portion 11. It is comprised from the wall part 12b which protrudes in between.

  In this transformer, as shown in FIG. 3, a rectangular tubular primary coil assembly 2 is inserted into the internal space through the opening between the side plates 5b of the secondary coil assembly 1, and the primary coil 2b is pulled out. A wire is passed through the groove 9 and connected to the mounting terminal 8, and a pair of opposed E-type core 3 middle legs 3 a are inserted into the primary coil assembly 2, and the outer legs 3 b are secondary. It is arranged between the terminal block 6 and the flange portion 12a of the insulating portion 12 along the side plate 5b of the side coil assembly 1, and is assembled by winding the tape 13 around the outer periphery of both E-type cores 3. .

  According to the transformer having the above configuration, the entire circumference of the U-shaped secondary coil 4 made of a strip-like copper plate is covered with the first bobbin 5 made of an insulating resin and integrated by insert molding. Since the secondary side coil assembly 1 is used, the secondary side coil assembly 1 and the primary side coil assembly 2 and the E-type core 3 can be easily assembled.

  In addition, in the mold for insert molding, the shape of the secondary coil 4 and its mounting terminal 7 can be corrected so that the plate surface of the mounting terminal 7 can be located on the same plane, and after molding By integrating the secondary coil 4 and the first bobbin 5, a high-strength secondary coil assembly can be obtained.

In addition, since the first bobbin 5 of the secondary coil assembly 1 is integrally formed with a terminal mounting portion 6a provided with a mounting terminal 8 to which the end of the primary coil 2b is connected, The mounting terminals 7 and 8 of the secondary side coil 4 and the primary side coil 2 b can be positioned integrally in the secondary side coil assembly 1.
As a result, it is possible to manufacture the secondary coil assembly 1 with high accuracy, and hence it is possible to easily mount the secondary coil assembly 1 on the board.

Further, in the secondary coil assembly 1, the entire circumference of the secondary coil 4 is covered with an insulating resin, and the hole 11 formed by the support member of the secondary coil 4 at the time of insert molding is also used. The position of the support member is set in advance to a position deviating from the position facing the outer leg 3b of the E-type core 3, and the hole 11 and the outer leg 3b are formed in the side plate 5b of the secondary coil assembly 1. Insulating portion 12 protruding in a bowl shape from between the two is formed.
For this reason, the required creepage distance can be reliably ensured between the secondary coil 4, the primary coil 2 b, and the E-type core 3.

DESCRIPTION OF SYMBOLS 1 Secondary side coil assembly 2 Primary side coil assembly 2a 2nd bobbin 2b Primary side coil 3 E type core 3a Middle leg 3b Outer leg 4 Secondary side coil 5 1st bobbin 5a Top plate 5b Side plate 6a, 6b Terminal mounting part 7 Mounting terminal (secondary side)
8 Mounting terminal (primary side)
12 Insulation part

Claims (4)

A strip-shaped metal is formed into a ring-opened cylindrical shape to form a secondary coil, and both end portions thereof are bent so that the plate surfaces are located on the same plane to form mounting terminals. A secondary coil assembly in which a first bobbin made of an insulating resin is integrally formed on the entire circumference of
A primary side coil assembly in which a primary side coil is wound around the outer periphery of the second bobbin and disposed in the internal space of the secondary side coil assembly;
A transformer comprising: a secondary coil assembly and a core that surrounds an outer periphery of the primary coil assembly and forms a closed magnetic circuit.   The secondary side coil is formed in a U-shape bent in the out-of-plane direction, and the first bobbin is integrally formed by insert molding on the entire circumference thereof, whereby the secondary side coil assembly is connected to the top plate. The primary coil is formed in a square tube shape and has a pair of side plates, and is inserted into the top plate and the side plate of the secondary coil assembly. It consists of a pair of opposing E-shaped cores, each other's middle leg is inserted into the said primary side coil, and each other's outer leg is arrange | positioned along the said side plate of the said secondary side coil assembly. The transformer according to claim 1.   The side plate of the secondary coil assembly has the secondary coil at a position away from the position facing the outer leg of the E-shaped core due to the support member of the secondary coil at the time of the insert molding. The hole part which a part of side coil exposes is formed, and the insulation part which protrudes in a bowl shape from between the said hole part and the said core is formed, The Claim 1 or 2 characterized by the above-mentioned. Transformer.   2. A terminal mounting portion having a mounting terminal to which an end portion of the primary side coil is connected is integrally formed on the first bobbin of the secondary side coil assembly. 4. The transformer according to any one of 3 to 3.

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