JP2008103371A - Transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transformer having insulating performance conforming to safety standards of every country, and enabling to easily widely adjust the number of winding rates. <P>SOLUTION: This transformer includes a first coil block formed by winding a strip conductor having at least insulated one surface around a bobbin; one side obtained by dividing a second coil consisting of a plurality of second coil blocks formed by laminating a base coil as a thin plate conductor and an insulating paper; the other side of the divided second coil; a pair of cores having intermediate legs; and a casing for aligning positions of insertion holes each having a shape corresponding to the intermediate legs and provided for each of a finished body of the one side of the second coil, a finished body of the first coil block and a finished body of the other side of the second coil, and holding a stack of the finished bodies. In the transformer, the first coil block is insulated from the second coil by the casing and the bobbin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transformer having an insulation performance that conforms to the safety standards of each country, and particularly to a high-frequency, high-current transformer.

As an example of a conventional general transformer, as shown in FIG. 11, the primary and secondary coils are made of a round wire or a litz wire or the like in which a number of thin round wires are bundled for high frequency use as a conductor. There is.
In the above transformer, the secondary coil A5 is sandwiched between the divided primary coils A4 and wound around the bobbin A3 to produce a coil block. Next, the middle legs A1a and A2a of the pair of cores A1 and A2 are inserted into the insertion holes formed in the central portion of the bobbin A3.
Insulation in this transformer is performed by inserting, for example, insulating paper A6 between the primary and secondary coils. Further, this transformer secures a distance from other electrodes or the like for satisfying the insulation standards of each country by providing a barrier insulating part A7 at the coil end.

The transformer configured as described above uses round wires having coatings on the primary and secondary coils, and many insulators such as insulating paper A6 or barrier insulating part A7 between the coils and at the coil ends. In addition, since an insulating space is required, the conductor space factor is low, and the limit is 25 to 30%.
In addition, the large diameter round wire used for handling large currents has a large effect on the skin effect in the high-frequency region, so the effective effective area of the conductor is small, and the temperature that affects the reliability of the transformer itself. Invited to rise.

In order to suppress this temperature rise, it is necessary to further reduce the resistance of the winding (increase the diameter), which contributes to the increase in size of the transformer.
Further, the reduction in the resistance (increase in diameter) of the winding makes it difficult to increase the number of turns of the coil, and further deteriorates the coupling degree between the primary coil and the secondary coil. For this reason, for example, in order to remove the influence of the leakage inductance when the transformer is used in the inverter drive circuit, circuit measures are required and the cost is high. Furthermore, this deterioration in the degree of coupling has also become a factor that deteriorates the output voltage fluctuation rate when the output load fluctuates.

As another example of a conventional transformer, there is a type using a coil block in which thin plate conductors are laminated (for example, see Patent Document 1).
As shown in FIG. 12, an example of the above transformer is provided at the center of a primary coil block B5 made of a similar thin plate conductor between a plate-like secondary coil block B4 made of a thin plate conductor. The pair of cores B1 and B2 are produced by inserting the middle legs B1a and B2a into the insertion holes.
Insulation in this transformer is performed by inserting insulating paper between the coil blocks and between the coil block and the core, or, as shown in FIG. I use it.

  Among the above-mentioned problems with transformers using round wires or litz wires, the above transformer has been improved in terms of the low degree of coupling between the primary coil and secondary coil, and the temperature rise, but to satisfy insulation performance, etc. The problem of the complexity of the production process and the high cost associated with the complexity of the production process has not been improved.

Further, the type of transformer in which the thin plate conductors are laminated has a problem that it is difficult to produce a primary coil having a large number of turns.
As one of the methods for realizing a multi-winding primary coil, a plurality of base coils (for example, C3a to c) and insulating paper (for example, C4a to c) are alternately stacked as shown in FIG. There is a method of connecting the drawn portions of the coils (for example, C5) as shown by a dotted line in the drawing.
However, in this method, as the number of stacked layers is increased, the dimensions of the lead-out portion C5 and the slit portion C6 of the base coil have to be reduced, which makes it difficult to manufacture. In addition, since it is necessary to produce base coils having different shapes, there is a problem that a plurality of molds must be prepared.
As another method for realizing a multi-turn primary coil, there is a method of forming a multi-turn coil pattern D2 wound at a slit interval D3 on the front and back surfaces of the base coil D1, as shown in FIG.
However, this method increases the production cost because the manufacturing process of the base coil itself involves the pattern formation of the printed circuit board, and the width of the coil pattern D2 becomes narrower and the current capacity decreases as the number of turns of the coil increases. There was a problem.
JP 2003-347125 A

  The present invention has an insulation performance that complies with the safety standards of each country, can easily adjust a wide range of turns ratio, has a high conductor space factor, suppresses heat generation in the high-frequency region, is small and thin, It is an object to provide a transformer that can be easily produced at low cost.

In order to solve the above-described problems, a transformer according to the present invention includes a first coil block formed by winding a strip-shaped conductor having at least one surface insulated around a bobbin, a base coil that is a thin plate conductor, and insulating paper. One side obtained by dividing a second coil composed of a plurality of second coil blocks formed, the other side of the divided second coil, a pair of cores having middle legs,
Insertion of a shape corresponding to the middle foot provided in each of the completed body on one side of the second coil, the completed body of the first coil block, and the completed body on the other side of the second coil A housing for holding these stacked bodies is provided while aligning the positions of the holes, and the first coil block and the second coil are insulated by the housing and the bobbin.

  Preferably, the base coil has one turn or two turns.

  Preferably, the base coil has an enlarged positioning hole and a positioning hole, and the insulating paper has a positioning hole at a position corresponding to the enlarged positioning hole and the positioning hole of the base coil.

  Preferably, a third coil made of a round wire is wound around the bobbin.

  Preferably, the winding start tip portion of the strip-shaped conductor wound around the bobbin is bent toward the winding center.

  Preferably, the winding end portion of the strip-shaped conductor wound around the bobbin is performed so as to sandwich a spacer disposed on the winding center side of the winding end portion, and the drawing direction of the winding end portion is predetermined. It is kept in the specified direction.

  Preferably, the first coil block has a first external terminal attached in advance to the bobbin, and a first end connected to a winding start portion and a winding end portion of a strip-shaped conductor wound around the bobbin. 1 terminal connection plate and a terminal engagement groove for engaging with the first external terminal are cut out and connected to the first external terminal and the other end of the first terminal connection plate. Relay brackets.

  Preferably, the casing is formed on at least one second coil block contact surface orthogonal to a middle leg of the core and a part of a peripheral edge of the second coil block contact surface. A plurality of support walls perpendicular to the coil block contact surface; and at least one storage portion surrounded by the second coil block contact surface and the support wall, wherein the second coil block has the same shape The base coil is composed of a superposed body in which the two base coils are turned upside down and the insulating paper is sandwiched between them and the positions of the insertion holes are aligned with each other. The insulating paper has a base coil connection hole formed in an opening, and the two base coils are respectively connected to the base coil connection surface on the surface in contact with the insulating paper. And a connecting projection having a height substantially equal to ½ of the thickness of the insulating paper, and the second coil block is connected to the base coil via the base coil connecting hole. The corresponding connecting projections are connected and overlapped, and are expanded to an area limited by the support wall.

  Preferably, a plurality of notches are formed in a peripheral edge portion of the insulating paper of the second coil block, and a plurality of inner wall projections are formed inside the support wall, and the corresponding notches and the inner walls are formed. The protrusions engage with each other, and the second coil block is held in the storage portion.

  Preferably, a plurality of the second coil blocks are stored in the storage portion, and the two base coils of the plurality of second coil blocks are respectively interposed between the support walls of the storage portion. An external terminal mounting portion that protrudes, and the external terminal fixing surface outside the housing includes a second external terminal that connects the plurality of external terminal mounting portions to each other outside the housing, The connection part of the external terminal 2 with the external terminal mounting part is bent so as to be separated from the housing.

  Preferably, in the housing, the first coil block is held between the two second coil block contact surfaces, and the housing is based on the two second coil block contact surfaces. And the first external terminal is disposed on one of the storage portions when the first coil block is held in the housing, and the one storage portion The second coil block held on the side and the side surface of the insulating paper disposed on the first external terminal side, and the second coil block contact of the insulating paper farthest from the second coil block contact surface A protective cover is attached so as to cover a part of the surface not facing the surface.

  According to the present invention, the insulation performance conforms to the safety standards of each country, wide adjustment of the turns ratio can be easily performed, the conductor space factor is high, the heat generation in the high frequency region is suppressed, and the small and thin type Thus, a transformer that can be easily produced at low cost can be provided.

[Explanation of terms]
In the present specification, “one turn” means that the coil is wound once around the core middle leg. Here, the winding of the coil is not limited to the state where the coil is wound directly around the bobbin or the core middle leg so that the path of the current flowing through the coil can exist in the circumferential direction of the core middle leg. As long as it is arranged. Similarly, “two turns” means that the coil is wound twice around the core middle leg.

  In the present specification, the “turn ratio” means a turn ratio of another coil to one coil.

  Further, in this specification, the “conductor space factor” is the ratio of the area occupied by the conductor portion such as the winding or thin plate conductor in the entire cross-sectional area of the region where the winding or thin plate conductor constituting the coil is arranged. Means. In other words, the “conductor space factor” means the ratio of the area excluding the space between the windings and the region such as the coating of the windings.

  In the present specification, “degree of coupling” means the degree of coupling of magnetic flux between coils. When the leakage inductance increases, the “coupling” decreases.

  First, the structure of the transformer according to the present invention will be described with reference to FIG.

The transformer according to the present invention is mainly composed of a first coil block 100, a plurality of second coil blocks 91 to 94, a housing 4 for housing them, and a pair of cores 1 and 2.
Since the first coil 8 of the first coil block 100 is manufactured by winding a strip-shaped conductor around the bobbin 3, the number of turns can be easily increased. First terminal connection plates 82 and 83 are connected to a winding start portion and a winding end portion corresponding to substantially both ends of the first coil 8, respectively.
The second coil block (for example, 91) includes a base coil 61a that is a thin plate conductor (preferably one turn. Each base coil is hereinafter described as one turn), and a base coil having the same shape as the base coil 61a. The insulating paper 51 is sandwiched between the base coils 61b that are turned upside down. As will be described later, since the base coils 61a and 61b are connected in series, the number of turns of the second coil block 91 is two.
The produced first coil block 100 and second coil block are housed in the housing 4. Here, since the first coil block 100 is housed in the casing 4 so as to be surrounded, the first coil block 100 and the second coil block are insulated by the casing 4 and the bobbin 3. Is done.
One or a plurality of second coil blocks can be stored. In the case of a plurality of the second coil blocks, the second coil block can be stored separately in the first storage portion 4a or the second storage portion 4b of the housing 4. In FIG. 1, four second coil blocks 91 to 94 are housed in the first housing portion 4a and the second housing portion 4b. When a plurality of second coil blocks are used, they are connected to each other by the second external terminals 71 and 72. In FIG. 1, the second coil blocks 91 to 94 are all electrically connected in parallel, and as a result, the second coil 9 is a two-turn coil as a whole.
In the cores 1 and 2, after the first coil block 100 and one or more second coil blocks are housed in the housing 4, the middle legs 1 a and 2 a are inserted into the insertion holes 10 so as to penetrate them. Attached.

In the transformer according to the present invention, FIG. 2 is a circuit diagram when the first coil 8 is the input (primary) side and the second coil 9 composed of the second coil blocks 91 to 94 is the output (secondary) side. Shown in
As described above, the first coil 8 is formed by winding a strip-shaped conductor and has a larger number of turns than the second coil 9 having two turns.
Since the input / output voltage ratio of the transformer is proportional to the turns ratio of the primary / secondary coil, the transformer shown in FIG. 2 operates as a step-down transformer whose output voltage is smaller than the input voltage.

Thus, the transformer according to the present invention shown in FIG.
(1) The number of second coil blocks 91 to 94, the number of turns per base coil, or the second coil block, in which the number of turns of the strip-shaped conductor constituting the first coil 8 is changed or accommodated in the housing 4 By changing the connection method (series / parallel) of the second external terminals 71 and 72 that mutually connect each other, the second coil 9 that easily includes the first coil 8 and a plurality of second coil blocks. The turns ratio can be changed, and a wide range of input / output voltage ratios can be adjusted.
(2) Since the first coil 8 and the second coil blocks 91 to 94 are made of a base coil of a thin plate conductor, a bobbinless structure is possible, the conductor space factor can be increased, and in the high frequency region Heat generation can be suppressed. This heat generation is reduced by the skin effect that the current flows only near the surface of the conductor by using the first coil as a thin strip conductor and the second coil as the base coil of the thin conductor. It is surmised that it was improved because of this.
(3) The first coil 8 having a large number of turns formed by winding the strip-shaped conductor around the bobbin 3 and the second coil 9 including the plurality of second coil blocks 91 to 94 are combined to form a small size.・ Thinning can be realized.
(4) The magnetic coupling area of the first coil 8 and the second coil 9 composed of a plurality of second coil blocks can be increased, and between the first coil 8 and the second coil 9. The distance can be reduced.
(5) The first coil block 100 and the second coil blocks 91 to 94 are produced completely independently. Thereafter, the completed first coil block 100 and second coil blocks 91 to 94 need only be combined with the housing 4, and the coil block 200 can be manufactured inexpensively, efficiently and stably. it can.
(6) Since the second coil blocks 91 to 94 can be configured by superimposing thin base conductor base coils (for example, 61 a and 61 b of the second coil block 91) formed from the same mold, There is no need to prepare multiple molds.

  Next, an embodiment of a transformer manufacturing method and configuration according to the present invention will be specifically described with reference to the drawings.

  3 is an enlarged view of the first coil winding start portion, FIGS. 4A to 4D are perspective views, cross-sectional views, and schematic top views of the first coil block, and FIGS. 5A to 5D are first views. FIG. 6 is a partial vertical cross-sectional view of the second coil block, FIG. 7 is a perspective view of a housing that houses the first and second coil blocks, and FIG. ) (B) is a plan view of the second coil block housed in the housing and a partially enlarged view thereof, and FIGS. 9A and 9B are housing the second coil block in the housing and providing a protective cover. FIG. 10 is a partial vertical cross-sectional view of a second coil block housed in a housing. FIG. In FIG. 1, FIG. 2 and each of the above drawings, the same components are denoted by the same reference numerals.

[First step: First coil block production]
In the first step, a strip-shaped conductor having at least one surface insulated by coating or polyester tape is wound around the bobbin 3 to form the first coil 8, and the first coil block 100 is manufactured. First terminal connection plates 82 and 83 are connected to the winding start portion and the winding end portion of the first coil 8, respectively. Furthermore, a third coil 87 is formed in the first coil block 100 as necessary.

  In FIG. 3, the enlarged view of the winding start part of the 1st coil 8 formed at this process is shown. The first terminal connection plate 82 is provided to pull out the first coil winding start portion 8b, which is one end of the strip-shaped conductor constituting the first coil 8, to the outside. Here, the end of the first coil winding start portion 8b is sharp, and there is a risk of damaging the strip-shaped conductor being wound. In order to prevent this, the first coil winding start portion 8b has a first coil winding start tip portion 8a protruding by a length A, and as shown in FIG. It is bent toward Thereby, it is possible to prevent damage to the strip-shaped conductor wound while being in contact with the first coil winding start portion 8b, and it is possible to manufacture the first coil 8 with stable quality. The first terminal connection plate 82 and the strip conductors constituting the first coil 8 are connected by soldering, welding, crimping, or the like.

  FIG. 4B shows a partial cross-sectional view of the first coil block 100 on the A plane in FIG. A first terminal connection plate 83 for pulling out the first coil winding end portion 8c to the outside is attached to the strip conductor forming the first coil 8 in advance. The first coil winding end portion 8c corresponds to the other end of the strip-shaped conductor to which the first terminal connection plate 82 is attached. When the winding end portion 8c of the strip-shaped conductor is wound, the first coil 8 is wound so as to sandwich the spacer 84 disposed on the winding center side, and ends. As a result, the connection direction of the connection plate 3a of the bobbin 3 and the drawing direction of the first coil winding end 8c at the end of winding can be kept substantially parallel, and the first terminal connection plate 83 can be fixed to the bobbin 3. It becomes easy.

  Here, in this embodiment, in order to improve the winding workability of the first coil 8, a first coil extension portion 8d obtained by extending the first coil winding end portion 8c is provided.

Subsequent to the formation of the first coil 8, a third coil made of a film-coated round wire (for example, a magnet wire) or a coated round wire (for example, a PVC electric wire) is formed. In the present embodiment, the third coil serves as an auxiliary power supply coil that supplies power to the primary control circuit, for example. The auxiliary power supply coil is provided when a transformer is used in a switching power supply circuit that does not have a power supply for the primary control circuit.
FIG. 4C illustrates a cross-sectional view of the B surface in FIG. The part indicated by “10” in FIG. 4C indicates an insertion hole for inserting the middle leg of the core, and does not indicate that the bobbin 3 is divided into two. Of the third coil 87 wound around the bobbin 3, 87 a is wound between the first coil 8 and the first terminal connection plate 82 between the gaps 3 c in the forward direction from the back of the page. On the other hand, the third coil 87b is wound in the back direction from the front of the page between the gap 3d between the first coil 8 and the bobbin 3. The third coil 87a and the third coil 87b are made of one round wire or a covered round wire.

The inner peripheral side of the third coil excluding the first coil winding start portion 8b and the first terminal connection plate 82 mounting portion (the inner periphery of the third coil 87a) shown in FIG. A bobbin step portion 3b is provided on the inner circumference of the third coil 87b. By adjusting the shape of the bobbin step 3b, for example, the third coil 87 can be disposed adjacent to the vicinity of the center of the winding height H of the first coil 8. Further, the bobbin step portion 3b can wind the first coil while reliably leaving the gaps 3c and 3d for winding the third coil 87.
As a result, the transformer of this embodiment can stabilize the magnetic coupling between the first coil 8 and the third coil 87, and can obtain good electrical characteristics. Further, as shown in FIG. 4C, the diameter of the third coil 87 is sufficiently smaller than the first coil width W. Therefore, even if the third coil is formed, the thickness of the first coil block 100 is increased. There is almost no effect on D.

Next, the L-shaped relay fittings 85 and 86 are attached. FIG. 4D shows a schematic view of the L-shaped relay fittings 85 and 86 as viewed from above. As shown in FIG. 4D, terminal engagement grooves 85a and 86a are formed in the L-shaped relay fittings 85 and 86, respectively. The terminal engaging grooves 85a and 86a engage with the first external terminals 88 and 89 in the shape of round bars previously attached to the bobbin 3, respectively, and the other ends of the first terminal connecting plates 82 and 83 (see FIG. L-shaped relay fittings 85 and 86 are attached so as to be in contact with 4 (D) (not shown).
As described above, one end of the first terminal connection plates 82 and 83 is connected to the first coil winding start portion 8b and the first coil winding end portion 8c, respectively. As a result, the first coil winding start portion 8b is connected to the first external terminal 88 via the first terminal connection plate 82, and the first coil winding end portion 8c is connected to the first terminal connection. It will be connected to the first external terminal 89 through the plate 83.
At the end of this step, the end of the third coil 87 is connected to the corresponding external terminal by soldering, and the manufacture of the first coil block 100 is completed.

[Second step: Production of second coil block]
In the second step, as shown in FIG. 1, for example, a base coil 61a (one turn in the present embodiment), which is a thin plate conductor, and a base coil 61b in which a base coil having the same shape as the base coil 61a is reversed are insulated. The second coil block 91 is produced by overlapping the paper 51 while sandwiching the paper 51. In the present embodiment, in order to increase the current capacity of the second coil 9, four second coil blocks are connected in parallel (second coil blocks 91 to 94).

FIG. 5A to FIG. 5C are plan views of the respective components of the second coil block. For example, FIGS. 5A, 5B, and 5C are the base coil 61a, the insulating paper 51, and the base coil 61b in FIG. 1, respectively. The base coils 61a and 61b have the same shape, and FIG. 5A and FIG. In addition, the connection convex parts 61c and 61d for connecting the base coils to each other at the positions corresponding to the base coil connection holes 51a of the insulating paper 51 on the back surface of the base coil 61a and the surface of the base coil 61b. Is formed.
Although details will be described later, the superposition of the base coils in the present invention is performed by pressing the connecting convex portions formed on the two base coils with the insulating paper sandwiched therebetween. As a result, the base coils are electrically and mechanically connected only by the connecting projections. Further, the insulating paper is sandwiched between two base coils in which the connecting projections are pressure-bonded so that the positional relationship with the base coil does not shift.

In this embodiment, the base coils 61a and 61b and the insulating paper 51 are provided with enlarged positioning holes 61e and 61f ′ (about φ2 mm in this embodiment) and positioning holes 61e ′, 61f, 51b and 51b ′ (this embodiment). Then, about φ1 mm) is formed. In the base coil 61a, the enlarged positioning hole 61e and the positioning hole 61e ′ are arranged symmetrically with respect to the center line CC.
As apparent from FIGS. 5B and 5C, the enlarged positioning holes or positioning holes formed in the base coil 61b and the insulating paper 51 are arranged in the same manner as the enlarged positioning holes 61e and 61e ′. Has been. The enlarged positioning hole and the positioning hole are used for accurately determining the relative positions of the base coils 61a and 61b and the insulating paper 51 when they are overlapped.

FIG. 5D is a plan view of the state in which the base coils 61a and 61b and the insulating paper 51 are overlapped so that the positions of the corresponding enlarged positioning holes or positioning holes coincide with each other. FIG. 5D corresponds to the second coil block 91 in FIG. 1, and is a two-turn coil in which two one-turn base coils are overlapped and connected in series.
In the present embodiment, the outer dimension of the insulating paper 51 is larger than the base coils 61a and 61b as a whole. On the other hand, the insulating paper 51 has a smaller opening area of the insertion hole 10 opened in a shape corresponding to the middle leg of the core to be attached in the final process of manufacturing the transformer. Thereby, the base coils which comprise a 2nd coil block, or the base coil and the center leg of a core can be insulated.

  Connection of the base coils 61a and 61b when the second coil block 91 is formed will be described with reference to FIG. 6 which is a cross-sectional view taken along the line DD of FIG. The base coils 61a and 61b are overlapped with an insulating paper 51 having a thickness d interposed therebetween. As described above, the base coils 61a and 61b are provided with connection convex portions 61c and 61d having a height of approximately d / 2 at portions corresponding to the base coil connection holes 51a of the insulating paper 51, respectively. When the connecting projections 61c and 61d facing each other come into contact with each other, the base coils 61a and 61b can be reliably connected even when the insulating paper 51 is sandwiched.

In addition, a plurality of notches (for example, 61 g, 51 c, 61 h, etc.) are formed in the peripheral portions of the base coils 61 a and 61 b and the insulating paper 51, and when the second coil block is mounted on the housing 4. At the same time, the base coils 61a and 61b insulated by the insulating paper 51 are prevented from contacting unnecessary portions (detailed in the third step).
Since the diameter of the enlarged positioning hole 61e is larger than the diameter of the positioning holes 51b and 61f, and the positioning holes 51b and 61f have the same diameter, the base coils 61a and 61b come into contact with each other through the enlarged positioning hole or the positioning hole. There is nothing.

[Third step: production of second coil]
In the third step, the second coil block 92, the insulating paper 50b, the second coil block 91, and the insulating paper 50a are sequentially stacked and stored in the first storage portion 4a of the housing 4, and similarly the second storage. In the part 4b, the second coil block 93, the insulating paper 50c, the second coil block 94, and the insulating paper 50d are sequentially stacked and stored. Subsequently, the second external terminals 71 and 72 interconnect the external terminal mounting portions (for example, 70a and 70b, which will be described in detail later) of the second coil blocks, and the second coil blocks 91 to 94. Are connected in parallel.

FIG. 7 shows a perspective view of the housing 4. The housing 4 has second coil block contact surfaces 4a ′ and 4b ′, and a support wall 4w perpendicular to the second coil block contact surfaces 4a ′ and 4b ′ except for a part thereof at the periphery. Is provided. The second coil block contact surface 4a ′ and the support wall 4w form a first storage portion 4a, and the second coil block contact surface 4b ′ and the support wall 4w form a second storage portion 4b. . In the present embodiment, the height of the support wall is determined so that the combined height of the cores 1 and 2 attached in the fifth step is equal to the height of the housing 4.
A plurality of inner wall projections (for example, 4f, 4f ′) are provided on the inner wall of the support wall 4w.

FIG. 8A shows a plan view of a state in which the second coil block 91 is housed in the first housing portion 4a of the housing 4 shown in FIG. The outer dimension of the insulating paper 51 in the second coil block 91 stored in the first storage unit 4a is limited by the support wall 4w. In the present embodiment, the second coil block has a shape expanded to the full limit of the support wall 4w in order to increase the current capacity of the second coil.
Further, since the notch portion (for example, 51c) of the insulating paper 51 and the inner wall protrusion (for example, 4f) of the support wall 4w are engaged, the second coil block 91 is stabilized in the first storage portion 4a. Is held. In this embodiment, the inner wall projection is not formed at a location corresponding to the inner wall projection 4f ′ of the second storage portion 4b. Instead, the two projections 20b provided on the protective cover 20 and Corresponding cutout portions of insulating paper (for example, 50d) engage (described later with reference to FIG. 9B).

FIG. 8B is a partially enlarged view of FIG. As shown in FIG. 8B, the base coil 61a is a region on the left side of the solid line indicated by reference numeral 61a, the base coil 61b is a region on the left side of the dotted line indicated by reference numeral 61b, and the insulating paper 51 is indicated by reference numeral 51. It is located in the region on the left side of the broken line shown. That is, in FIG. 8B, the region of the base coil 61a and the region of the base coil 61b excluding the notch 61g overlap each other, and the region of the base coil 61a and the region of the base coil 61b are respectively formed on the insulating paper 51. It overlaps with the area.
As is clear from FIG. 8B, the inner wall projection 4f of the support wall 4w and the cutout portion 51c of the insulating paper 51 have corresponding shapes. The base coils 61a and 61b are smaller than the insulating paper 51 as a whole. In other words, the peripheral edges of the base coils 61 a and 61 b are inside the peripheral edge of the insulating paper 51 and are separated from the support wall 4 w in the portions other than the notches. Furthermore, since the notch 61g of the base coil 61a is formed larger than the notch 51c of the insulating paper 51, the base coil 61a and the support wall 4w do not contact each other.
On the other hand, the notch of the base coil 61b corresponding to the inner wall projection 4f is not formed, and the periphery of the base coil 61b is substantially coincident with the periphery of the notch 51c of the insulating paper 51. Therefore, the base coil 61b may come into contact with the support wall 4w. However, as described above, the base coil 61a and the support wall 4w do not contact each other. As a result, the notches 51c and 61g having different sizes prevent the base coils 61a and 61b from coming into contact with each other via the support wall 4w.
Further, in the present embodiment, as is apparent from FIG. 8B, the second coil block includes the notch portion (for example, 51c) and the inner wall protrusion (for example, 4f) of the insulating paper in the housing housing portion. The notch 61g of the base coil 61a does not contribute to this holding.
The engagement between the inner wall protrusion of the support wall and the notch portion of the insulating paper shown in FIG. 8B and the positional relationship between the support wall, the base coil, and the insulating paper are the same in the other engaging portions of the support wall and the insulating paper It is the same. The engagement between the protective cover 20 and the insulating paper will be described later with reference to FIG.

  As described above, in this embodiment, the second coil block can be stably held in the housing while maintaining the necessary high insulation. In addition, the bobbin for winding the second coil can be omitted, and the base coil area can be expanded to substantially the same area as the casing, leaving a small space for maintaining insulation. For this reason, the 2nd coil in a present Example has a high conductor space factor, and can enlarge current capacity.

Subsequently, the protective cover 20 is attached. In FIG. 9A, the second coil blocks 91 and 92 and the insulating papers 50a and 50b are stored in the first storage part 4a, and the second coil blocks 93 and 94 and the insulating papers 50c and 50d are stored in the second storage part. It is a longitudinal cross-sectional view which shows the state which accommodated in 4b and attached the protective cover 20. FIG. In the present embodiment, among the paper stored in the first storage portion 4a, the insulating paper 50a is disposed farthest from the second coil block contact surface 4a ′. Similarly, among the paper housed in the first housing portion 4b, the insulating paper 50d is disposed farthest from the second coil block contact surface 4b ′.
The housing 4 includes a space corresponding to the thickness D of the first coil block 100 between the second coil block contact surface 4a ′ and the second coil block contact surface 4b ′. In the next step (fourth step), the first coil block 100 is inserted and fitted into this space from the housing opening 4d along the arrow X. When the first coil block 100 is held in the housing 4, the positions of the insertion holes 10 are aligned. In the present embodiment, the first external terminal 88 of the first coil block 100 is disposed in the vicinity of the second storage portion 4b across the support wall 4w having the housing inner surface 4h. Another first external terminal 89 not shown in FIG. 9B is also arranged in the same manner.

The protective cover 20 has a shape in which a rectangular thin plate is bent at a right angle along the longitudinal direction, and its cross section is L-shaped as shown in FIG. Further, as shown in FIG. 9B, the length of the protective cover 20 in the longitudinal direction and the width of the second storage portion 4b of the housing 4 correspond to each other.
The protective cover 20 fills a gap between the housing inner surface 4h and the second coil blocks 93 and 94 housed in the second housing portion 4b of the housing 4 and covers a part of the lower surface of the insulating paper 50d. It is attached as follows. As a result, the protective cover 20 covers a part of the lower surface of the insulating paper 50d disposed in the lowermost layer, and the side surfaces of the second coil blocks 93 and 94 and the insulating paper 50c and 50d on the housing inner surface 4h side. It becomes.
As shown in FIG. 9B, the inner wall projection 4h is not formed with an inner wall projection that engages with a notch (eg, 50e) of insulating paper (eg, 50d). Instead, the inner surface 20a of the protective cover 20 is formed with two projections 20b that play the same role as the inner wall projection 4f ′ in the first storage portion 4a. The projection 20b and the insulating paper 50d correspond to each other. The notches 50e are engaged with each other.
By attaching the protective cover 20 in this manner, a creepage of 9 mm or more is formed between the first external terminal 88 and the second coil blocks 93 and 94 housed in the second housing portion 4b of the housing 4. A distance can be secured.

At the end of this step, the second external terminal is attached. The second external terminal is attached to an external terminal attachment portion (for example, 70b in FIG. 8) of the second coil block formed so as to protrude from the portion without the support wall 4w to the outside of the storage portion.
FIG. 10 is a partial vertical cross-sectional view taken along line EE of FIG. 8 of the housing 4 in which the second coil blocks 91 to 94 are accommodated. The second external terminal 72 serves as an external terminal of a second coil having a sufficient current capacity for connecting a plurality of (four in this embodiment) second coil blocks in parallel. The second external terminal 72 is formed with an insertion hole (not shown), in which an external terminal mounting portion 70b (see FIG. 8) of the base coil 61b, and base coils 62b and 63b corresponding thereto. 64b, and the base coil and the second external terminal 72 are connected by solder 72a, 72b. At the same time, the second external terminal 72 engages with the positioning protrusion 4g formed on the external terminal fixing surface 4c of the housing 4 and is fixed to the external terminal fixing surface 4c. Similarly, on the back side of the second external terminal 72, the external terminal mounting portions of the base coils 61a, 62a, 63a, and 64a are connected, and the second external terminals 71 (not shown) are connected in parallel. Is attached.
As shown in FIG. 10, the connection portions of the second external terminals 72 and 71 (not shown) with the external terminal mounting portions (for example, 70b in FIG. 8) of the respective base coils are compared with other portions. The housing 4 is separated from the external terminal fixing surface 4c. As a result, the solders 72a and 72b can be soldered by a solder bath, not by manual soldering.

[Fourth step: coil block production]
In the fourth step, as shown in FIG. 1, the first coil block 100 produced in the first step is applied to the housing opening 4d of the housing 4 in which the second coil block has been accommodated in the third step. The coil block 200 is manufactured by inserting and fitting.

  As described above in the first to third steps, in the present invention, the production of the first coil block 100 (first step) and the production of the second coil block (second step) do not depend on each other. Completely independent. In other words, in the third and fourth steps, it is only necessary to combine those completed in the previous step, and it is possible to produce a transformer of stable quality with low cost and efficient man-hours.

[Fifth step: core mounting]
As shown in FIG. 1, each component of the coil block 200 produced in the fourth step has an insertion hole 10 having a shape corresponding to the middle leg of the core so as to penetrate from the insulating paper 50a side to the insulating paper 50d side. Is provided. In the final process of manufacturing the transformer according to the present invention, the cores 1 and 2 having the middle legs 1a and 2a are inserted into the insertion hole 10 to complete the first coil, the second coil, and the housing. Combined with 4, the transformer is finally completed.
As a result, a magnetic circuit interlinking with the first coil and the second coil is formed and functions as a transformer. An appropriate creepage distance is provided between the core middle legs 1a and 2a and the first coil 8 and the second coil 9, and between the second coil 9 and the first external terminals 88 and 89. In addition, the distance is maintained and the safety standards of each country can be satisfied.

[Modification]
(1) In the embodiment, four second coil blocks having two turns are used as the second coil, and the two coils are stored in two storage portions so as to sandwich the first coil. However, the present invention is not limited to this. . That is, (i) the number of turns per base coil is set to 2 or more, (ii) the number of base coil stacks per second coil block is increased, or (iii) the second coil block is not divided. The number of the second coil blocks stored in one storage unit or (vi) the number of the second coil blocks stored in the housing may be increased or decreased, and it is possible to meet various characteristics requirements.
(2) In the embodiment, all the second coil blocks constituting the second coil are connected so as to be electrically in parallel. However, some or all of them are connected depending on the connection of the second external terminal. Can be changed in series to meet various requirements.
(3) In the embodiment, the width of the second coil occupies substantially the entire area surrounded by the support wall except for the portion where the middle leg of the core is inserted, with emphasis on the current capacity of the second coil. Although a wide base coil is used, other shapes can be used in consideration of other conditions such as heat dissipation.
(4) Further, in the embodiment, the cross-sectional shape of the middle leg of the core is a rectangle with a corner cut, but the shape is not limited to this and may be another shape. However, when changing to another shape, it is necessary to simultaneously change the bobbin, the housing, and the insertion hole of the second coil block formed in a shape corresponding to the shape of the middle leg of the core.
(5) Further, in the embodiment, the positioning hole and the enlarged positioning hole are provided in order to accurately superimpose the base coil or the like in the production of the second coil block. It is not limited. Furthermore, the engagement of notch portions such as insulating paper provided to insulate and fix the second coil block in the housing and the inner wall protrusions formed on the support wall and protective cover of the housing are also different from each other. It may be replaced with a fixing method.
(6) In the embodiment, the second coil block is housed in the housing (third step) and then the first coil block is inserted and fitted (fourth step). However, this order is reversed. Can do.
(7) In the embodiment, the first coil is a primary coil and the second coil is a secondary coil, which is a step-down transformer. However, this may be reversed to form a step-up transformer.

FIG. 3 is an exploded perspective view of a transformer according to the present invention. It is a circuit diagram of a transformer according to the present invention. It is a winding start part enlarged view of the 1st coil of the transformer concerning the present invention. It is the 1st coil block of the transformer concerning the present invention, (A) is a perspective view, (B) is a transverse partial sectional view, (C) is a longitudinal section, (D) is attachment of an L-shaped junction metal fitting FIG. 2A and 2B are a second coil block and its constituent elements of a transformer according to the present invention, wherein (A) and (C) are plan views of the base coil, (B) is a plan view of insulating paper, and (D) is insulated from the base coil. It is a top view of the 2nd coil block which laminated | stacked paper. It is a fragmentary longitudinal cross-sectional view of the 2nd coil block of the transformer which concerns on this invention. It is a perspective view of the housing | casing which accommodates the 1st and 2nd coil block of the transformer which concerns on this invention. It is a top view which shows the state which accommodated the 2nd coil block in the housing | casing of the trans | transformer which concerns on this invention, Comprising: (A) is a general view, (B) is a partially expanded view. FIG. 5A is a longitudinal sectional view, and FIG. 5B is an enlarged plan view of a state in which the second coil block is housed in the casing of the transformer according to the present invention and a protective cover is attached. It is a fragmentary longitudinal cross-sectional view of the state which accommodated the 2nd coil block and insulating paper in the housing | casing of the trans | transformer which concerns on this invention. It is a longitudinal cross-sectional view of the conventional transformer. It is a longitudinal cross-sectional view of the conventional transformer. It is a disassembled perspective view which shows the laminated structure of the conventional transformer. This is a multi-turn base coil used in a conventional transformer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core 1a Middle leg 2 Core 2a Middle leg 3 Bobbin 3b Bobbin step part 3c, 3d Gap 4 Case 4a 1st accommodating part 4a '2nd coil block contact surface 4b 2nd accommodating part 4b' 2nd coil block contact Surface 4c External terminal fixing surface 4d Housing opening 4f, 4f 'Inner wall projection 4g Positioning projection 4h Housing inner surface 4w Support wall 50a-50d Insulating paper 50e Notch 51-54 Insulating paper 51a Base coil connection holes 51b, 51b' Positioning Hole 51c Notch 61a, 61b Base coil 61c, 61d Connection convex part 61e, 61f 'Enlarged positioning hole 61e', 61f Positioning hole 61g, 61h Notch 62a, 62b Base coil 63a, 63b Base coil 64a, 64b Base coil 70a, 70b External terminal mounting portions 71, 72 Second external terminals 72a, 72b Solder 8 First coil a First coil winding start tip portion 8b First coil winding start portion 8c First coil winding end portion 8d First coil extension portion 82, 83 First terminal connection plate 84 Spacer 85, 86 L-shaped relay fitting 85a, 86b Terminal engaging groove 87 Third coil 87a, 87b Third coil 88, 89 First external terminal 9 Second coil 91-94 Second coil block 10 Insertion hole 20 Protective cover 100 First Coil block 200 Coil block

Claims (11)

A first coil block formed by winding a belt-like conductor having at least one surface insulated around a bobbin;
One side obtained by dividing a second coil composed of a plurality of second coil blocks formed by laminating a base coil that is a thin plate conductor and insulating paper;
The other side of the divided second coil;
A pair of cores having middle legs;
Insertion of a shape corresponding to the middle foot provided in each of the completed body on one side of the second coil, the completed body of the first coil block, and the completed body on the other side of the second coil A housing that holds these stacks while aligning the holes,
The transformer is characterized in that the first coil block and the second coil are insulated by the casing and the bobbin.   The transformer according to claim 1, wherein the base coil has one turn or two turns. The base coil has an enlarged positioning hole and a positioning hole,
The transformer according to claim 1, wherein the insulating paper has a positioning hole formed at a position corresponding to the enlarged positioning hole and the positioning hole of the base coil.   The transformer according to claim 1, wherein a third coil made of a round wire is wound around the bobbin.   5. The transformer according to claim 1, wherein a winding start tip portion of the strip-shaped conductor wound around the bobbin is bent toward the winding center.   The winding end portion of the strip-shaped conductor wound around the bobbin is performed so as to sandwich the spacer disposed on the winding center side of the winding end portion, and the drawing direction of the winding end portion is a predetermined direction. The transformer according to any one of claims 1, 4, and 5, wherein The first coil block further includes:
A first external terminal previously attached to the bobbin;
A first terminal connection plate having one end connected to each of a winding start portion and a winding end portion of a strip-shaped conductor wound around the bobbin;
A terminal engaging groove for engaging with the first external terminal is cut out, and includes the first external terminal and a relay fitting connected to the other end of the first terminal connecting plate. The transformer according to any one of claims 1 and 4-6. The housing is
At least one second coil block contact surface orthogonal to the middle leg of the core;
A plurality of support walls formed on a part of the periphery of the second coil block contact surface and perpendicular to the second coil block contact surface;
At least one storage portion surrounded by the second coil block contact surface and the support wall;
With
The second coil block is composed of an overlapping body in which the two base coils having the same shape are reversed from each other, the insulating paper is sandwiched therebetween, and the two are stacked while aligning the positions of the insertion holes,
The second coil block is held in the storage portion,
The insulating paper has a base coil connection hole formed with an opening,
The two base coils are connected to the surface of the insulating paper at a position corresponding to the base coil connecting hole at a position corresponding to the base coil connecting hole. Part
The second coil block is overlapped by connecting the corresponding connecting projections of the base coil via the base coil connection hole, and is expanded to an area limited by the support wall. The transformer according to any one of claims 1 to 7. A plurality of notches are formed in the peripheral edge of the insulating paper of the second coil block,
A plurality of inner wall projections are formed inside the support wall,
9. The transformer according to claim 8, wherein the corresponding notch and the inner wall protrusion are engaged with each other, and the second coil block is held in the storage portion. The storage unit stores a plurality of the second coil blocks,
Each of the two base coils of the plurality of second coil blocks has an external terminal mounting portion protruding from between the support walls of the storage portion,
The external terminal fixing surface outside the housing includes a second external terminal that connects the plurality of external terminal mounting portions to each other outside the housing,
The transformer according to claim 8 or 9, wherein a connecting portion of the second external terminal with the external terminal mounting portion is bent so as to be separated from the housing. In the housing, the first coil block is held between two contact surfaces of the second coil block,
The housing includes the two storage portions based on the two second coil block contact surfaces,
The first external terminal is disposed on one of the storage units when the first coil block is held in the housing.
A side surface of the second coil block and the insulating paper held in the one storage portion and disposed on the first external terminal side, and the insulating paper farthest from the second coil block contact surface. The transformer according to any one of claims 8 to 10, wherein a protective cover is attached so as to cover a part of the surface not facing the coil block contact surface.

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