JP5755211B2 - Substrate manufacturing method, injection-molded substrate - Google Patents

Description

  The present invention relates to a method for manufacturing a substrate such as a DC-DC converter used in an automobile or the like.

  A DC-DC converter used in an automobile includes a plurality of components such as a voltage conversion transformer and a smoothing choke coil. Of these components, components that are loaded with high voltage and large current need to be manufactured separately and then connected to the outside of the substrate. However, since such a configuration leads to an increase in the size of the apparatus, a more compact DC-DC converter has been required.

  On the other hand, there is a method in which a plurality of circuit materials are formed by pressing and the substrate is integrally formed by injection molding in a state where the circuit materials are joined (Patent Document 1).

JP 2011-146458 A

  According to the method of Patent Document 1, it is possible to use, for example, thick copper of 400 μm or more as a circuit material so that it can withstand a high voltage and a large current. Since the injection molding resin is filled, the insulating performance of the substrate is not deteriorated.

  On the other hand, the coil portion provided on the substrate is formed by laminating a plurality of circuit materials, for example. Usually, the interval between circuit materials constituting such a coil is narrow. Therefore, the circuit material may be deformed by the pressure of the resin during injection molding, and the circuit materials may come into contact with each other.

  FIG. 8 is a view showing a state where the circuit conductor 101 is installed in the mold 107 when a conventional injection-molded substrate is manufactured. As described above, the circuit conductor 101 is configured by joining a plurality of circuit materials. The circuit conductor 101 is provided with coil conductors 103a and 103b. The coil conductors 103a and 103b are configured by laminating a plurality of coil conductors.

  Conventionally, at the time of injection molding, the insulating material 105 is sandwiched between the coil conductors in order to maintain insulation without bringing the coil conductors into contact with each other. By sandwiching the insulating material 105, even when resin pressure is applied to the coil conductors during injection molding, the coil conductors can be prevented from being deformed and contacting the coil conductors.

  However, the use of an insulating material increases the number of components and requires man-hours and space for arranging the insulating material. Therefore, it has been difficult to obtain a more compact substrate at a lower cost.

  The present invention has been made in view of such problems, and provides a method for manufacturing a substrate capable of reliably ensuring insulation without using an insulating material for an injection molded substrate having a coil. The purpose is to do.

In order to achieve the above-described object, the first invention forms a plurality of circuit materials, joins predetermined portions of the circuit materials together to form a circuit conductor having a coil portion, and the coil portion has a flat plate shape. The coil material is provided in a spiral shape so that its diameter changes from the center, the width direction of the coil material is formed to be substantially parallel to the axial direction of the coil portion, and the circuit conductor is formed as an injection mold. When setting inside, a part of the coil conductor part of the coil part is inserted into a groove formed in the injection mold and spirally formed at a predetermined interval corresponding to the shape of the coil part. in, holding the coil conductor portion of the coil portion, a method of manufacturing a substrate, characterized in that the resin is injection molded to the injection mold in this state.

  In this case, the spiral shape of the coil portion may be a substantially rectangular shape. The coil portion may be formed by joining a plurality of the coil materials having a bent portion of approximately 90 °.

The coil portion may be formed such that the end portion of the innermost coil material is wider than other portions .

  According to the first invention, since a part of the coil conductor portion is injection-molded in a state of being fitted in the groove of the mold, the interval between the coil conductor portions can be reliably maintained even during the injection molding. Can do. Therefore, the coil conductors do not come into contact with each other, and mutual insulation can be ensured. At this time, there is no need to sandwich an insulating material or the like.

  In addition, since the current flows through the shortest path, the current flows in a biased manner toward the center of the coil. The coil portion is formed in a spiral shape so that the diameter changes from the center so that the width direction of the flat coil material is substantially parallel to the axial direction of the coil portion, so that the coil is formed on the center side of the coil. The flat part of the material can be turned. Therefore, as compared with the case where the coil material is arranged in a direction perpendicular to this, the cross-sectional area of the current concentration portion where the current substantially flows inside the coil can be increased. Therefore, the electrical resistance is reduced, so that heat loss and the like can be suppressed.

  In particular, the circuit material can be easily bent by making the coil spiral shape substantially rectangular. For example, as compared with the case where the coil material is rounded into a spiral shape, the shape of the bending process is more stable. For example, the interval between the coil materials can be processed with high dimensional accuracy. At this time, a plurality of coil materials having a 90 ° bent portion are joined to form the coil portion, so that it is not necessary to use a long coil material, and a short coil material can be combined. Therefore, the yield of the plate material is good and the productivity is high.

In addition, since the end of the innermost coil material is formed wider than the other part, the part located above the other coil material becomes the joint part between the coil material and the substrate side material. . If it does in this way, it can prevent that a substrate side material contacts with other coil materials.

2nd invention has a coil part, The circuit conductor by which the predetermined part of several circuit materials was joined, and injection molding resin which coat | covers at least one part of the said circuit conductor, The said coil part The flat coil material is formed in a spiral shape so that the diameter changes from the center, and the coil material is formed so that the wide direction thereof is substantially parallel to the axial direction of the coil portion. the portion of the width direction of the respective coil conductors formed on the, exposed from the injection-molded resin in a spiral shape at predetermined intervals, the coil exposed portion is formed is an injection molded substrate, wherein Rukoto .

An insulating resin may be applied to the coil exposed portion. The coil portion may have a substantially rectangular shape, and may be formed by joining a plurality of the materials having a bent portion of approximately 90 °. The coil part is formed such that the end of the innermost coil material is wider than the other part, and the part located above the other coil material is a joint part with the substrate side material. Also good.

  According to the 2nd invention, since a part of coil conductor part is exposed from injection molding resin, it is excellent in the heat dissipation of a coil part. Also, as described above, the coil portion is configured in a spiral shape so that the diameter changes from the center so that the width direction of the flat coil material is substantially parallel to the axial direction of the coil portion. The heat loss and the like can be suppressed by substantially increasing the cross-sectional area through which the current flows.

At this time, if insulating resin is applied to the coil exposed portion, the insulation of the coil exposed portion can be ensured. Further, the coil can be processed with high dimensional accuracy by making the spiral shape of the coil substantially rectangular. At this time, by forming a coil portion by joining a plurality of coil materials having a 90 ° bent portion, it is not necessary to use a long coil material, and a combination of short circuit materials can be used. Good yield and high productivity. Furthermore, the coil part is formed so that the end of the innermost coil material is wider than the other part, and the part located above the other coil material is a joint part with the substrate side material, It is possible to prevent the substrate side material from coming into contact with other coil materials.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a board | substrate etc. which can ensure insulation reliably can be provided, without using an insulating spacer with respect to the injection molding board | substrate which has a coil.

The perspective view which shows the board | substrate 1. FIG. The top view which shows the board | substrate 1. FIG. It is sectional drawing which shows the board | substrate 1, and is the sectional view on the AA line of FIG. (A) is a figure which shows the metal mold | die 19, (b) is a figure which shows the state which installed the circuit conductor 15 in the metal mold | die 19. FIG. (A) is sectional drawing which shows the state provided in the spiral shape so that a diameter may change from the center so that the wide direction of the flat coil conductor 4 may become substantially parallel to the axial direction of a coil part, (b) ) Is a cross-sectional view showing a state in which the width direction of the flat coil material is spirally formed in a plurality of layers so that the width direction is substantially perpendicular to the axial direction of the coil portion. (A) is a top view which shows the coil conductor 4b, (b) is the BB sectional drawing of (a). The figure which shows the other state which installed the circuit conductor in the metal mold | die 19a. The figure which shows the state which installed the conventional circuit conductor 101 in the metal mold | die 107. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a substrate 1, and FIG. 2 is a plan view. The substrate 1 is a substrate having a transformer 3 and a choke coil 5 and used as a DC-DC converter for an automobile, for example. In the substrate 1, the internal conductor portions are exposed to the outside in the electronic component mounting portion 7, the connection portions 8 a, 8 b, 8 c, the coil exposed portion 2, etc., and the other portions are covered with the injection resin 9.

  The transformer 3 provided on the substrate 1 is a voltage conversion coil, which steps down the current input from the outside by the transformer 3 and smoothes the stepped down current by the choke coil 5 and outputs it to the outside. The electronic component mounting part 7 is a part for mounting an electronic component or the like, and is electrically connected to the substrate 1 by, for example, a connection part 8b or the like.

  FIG. 3 is a cross-sectional view taken along line AA in FIG. A heat radiating part 11 is formed on the back side of the electronic component mounting part 7. The heat dissipating part 11 releases heat generated by energizing electronic circuit components and circuit conductors of the board to the outside. The substrate according to the present invention is not limited to the arrangement and shape as shown in the figure, and it goes without saying that other components and the like can be appropriately mounted and the arrangement and shape can be appropriately changed. .

  The substrate 1 is provided with circuit conductors 15 made of a plurality of circuit materials, and each circuit material is electrically connected as necessary. In the following description, the shape of the circuit conductor 15 is simply shown. However, the shape and arrangement of each circuit material and each of the circuit conductors 15 connected thereto are ensured so as to ensure the performance required for the substrate 1. Electronic parts and the like are set as appropriate. In such a state where the circuit conductors are properly assembled, the injection resin 9 is injected around.

  The transformer 3 and the choke coil 5 are constituted by coil conductors 4 and 4a, respectively. The coil conductors 4 and 4a are made of, for example, a plurality of coil materials. The coil material is flat, for example.

  In the illustrated example, the transformer 3 has a spiral shape so that the diameter changes from the center so that the wide direction of the flat coil material is substantially parallel to the axial direction of the transformer 3 (the left-right direction in FIG. 3). (Plan view). The choke coil 5 is spirally formed in a plurality of layers such that the wide direction of the flat coil material is substantially perpendicular to the axial direction of the transformer 3 (left-right direction in FIG. 3). Note that the configuration of each coil (the width direction of the coil material relative to the axial direction of the coil) is not limited to the illustrated example, and may be any direction.

  In the example shown in the drawing, a part of the coil conductor 4 of the transformer 3 is exposed from the injection resin 9 in the coil exposed portion 2. Therefore, the heat dissipation of the coil conductor 4 is excellent. In addition, although the coil exposure part 2 is a site | part exposed from the injection resin 9, you may coat | cover with another resin etc. after injection molding. For example, it may be covered with a heat conductive insulating resin or the like.

  The injection resin 9 is injected on the surface of the circuit conductor 15 and between the layers of the circuit conductor 15 so as to cover the circuit conductor 15 or to maintain the distance between the circuit materials. The injection resin 9 only needs to have insulating properties and can be injection-molded. For example, liquid crystal polymer, polyphenylene sulfide, polybutylene terephthalate, polyethersulfone, polyetheretherketone, polyphthalamide and the like can be used. .

  Next, details of the manufacturing method of the substrate 1 will be described. First, a necessary circuit material is punched out by a press, and a necessary bending process is performed to form a desired shape. At this time, an uneven shape may be provided on the surface of the press die, and a fine uneven shape may be formed on the surface of each circuit material. By increasing the surface roughness, the adhesion with the resin can be improved by the anchor effect. In addition to the formation of irregularities by a press die, the surface of the circuit material may be roughened by surface treatment by blast treatment, copper plating roughening, nickel plating roughening, or the like.

  Next, the circuit materials 15 are formed by bonding the circuit materials to each other or arranging them at predetermined positions. Joining is performed by welding, for example. The circuit conductor may be formed not only in a plane but also in a plurality of layers.

  Fig.4 (a) is sectional drawing which shows the metal mold | die 19 used for injection molding. 4A is a cross-sectional view corresponding to a cross section taken along line AA of the substrate 1 of FIG. The mold 19 is provided with a cavity 21 for injecting the injection resin 9. The cavity 21 is provided with a pin 25 at a predetermined position. A groove portion 23 is provided in a portion corresponding to the coil portion (coil exposed portion 2) of the mold 19. The groove 23 corresponds to the shape of the coil. That is, the groove interval of the groove portion 23 corresponds to the interval between the coil circumferences in the coil conductor 4.

  As shown in FIG. 4B, the circuit conductor 15 is fixed to the mold 19 by pins 25 at predetermined positions. A part of the coil material constituting the coil conductor 4 in the width direction is inserted into the groove 23. In this state, the substrate 1 is formed by injecting the injection resin 9 into the mold 19. As shown in the figure, it is not necessary to form grooves in the mold 19 for all the coil portions. For example, a portion corresponding to the choke coil (lower part in the figure) may be provided with an insulating material as usual.

  Since the coil conductor 4 is fitted into the groove portion 23, the interval between the coil materials is maintained even when the pressure of the injection resin 9 is applied during injection molding. Therefore, it can prevent that coil raw materials contact.

  Next, the form of the coil will be described. Fig.5 (a) shows the coil similar to the trans | transformer 3 (FIGS. 1-3) mentioned above. That is, the coil conductor 4 is formed in a spiral shape in a plan view (for example, from the top in FIG. 5), with the wide direction of the flat coil material arranged substantially parallel to the axial direction of the coil (up and down in the drawing). Is.

  When a high-frequency alternating current is passed through the coil conductor 4 in such a state, the current concentrates on the surface of the coil conductor 4 on the coil center 27 side. That is, one flat portion (wide surface) of the coil material becomes the current concentration portion 29.

  On the other hand, FIG. 5B corresponds to FIG. The direction of the coil material is 90 ° different. That is, the coil conductor 4 is formed such that the width direction of the flat coil material is arranged substantially perpendicular to the axial direction of the coil (up and down in the drawing), and the coil materials are laminated in a spiral shape.

  When a high-frequency alternating current is passed through the coil conductor 4 in such a state, the current concentrates on the surface of the coil conductor 4 on the coil center 27 side. That is, one end portion in the width direction of the coil material is the current concentration portion 29.

  Therefore, the case where the current concentration portion 29 is formed in the flat portion as shown in FIG. 5A is compared with the case where the current concentration portion 29 is formed at the end portion in the width direction as shown in FIG. In addition, the cross-sectional area of the current concentration portion 29 is increased. Therefore, FIG. 5A can suppress heat loss due to current concentration. In an electric vehicle or the like, a coil is usually used with a current of about 100 A to several hundred A. In this case, the heat loss can be reduced by about 20 to 30% in the case of FIG. 5A compared to the case of FIG.

  In the case of FIG. 5A, assuming a three-turn coil having a current value of about 100 A, for example, if a coil material having a thickness of 1 mm and a width of 5 mm is used, the space between the coil materials is 1 mm, and the core inner diameter d is The outer diameter is d + 2 × (3 turns × 1 mm + insulating layer 2 × 1 mm) = d + 10 mm. On the other hand, in the case of FIG. 5B, when a similar material is used, d + 2 × 5 mm width = d + 10 mm. Therefore, up to about 3 turns, the coils in FIGS. 5A and 5B have substantially the same size. If the number of turns is up to two, the size of the coil shown in FIG. 5A can be reduced. In consideration of the above-described current concentration, a smaller coil material can be used for the coil shown in FIG.

  As described above, according to the substrate 1 of the present embodiment, since the circuit material is formed by pressing, a thick copper substrate can be formed, and the injection resin 9 is formed by injection molding. An excellent substrate 1 that can withstand a large current can be obtained.

  Further, when a coil portion such as a transformer is formed by injection molding, the coil conductor 4 is inserted into the groove portion 23 in which the mold 19 is formed. Since the groove part 23 is formed in a spiral shape at a predetermined interval corresponding to the coil form, the insulation interval of the coil conductor 4 inserted into the groove part 23 is maintained. Therefore, it is possible to prevent the coil conductor 4 from being deformed and contacting the coil materials around each circumference during injection molding. In this way, the coil exposed portion 2 is formed. The coil exposed portion 2 can improve the heat dissipation of the coil. Moreover, in order to ensure the insulation of the coil exposure part 2, an insulating resin etc. can be separately apply | coated to the exterior of the injection resin 9 after injection molding.

  In addition, the coil part is made of a flat coil material, and the coil material has a spiral shape whose diameter changes from the coil center so that the width direction of the coil material is substantially parallel to the axial direction of the coil part. The concentrated portion 29 can be formed on the flat portion of the coil material. Therefore, heat loss can be suppressed as compared with the case where the coil material is substantially perpendicular to the axial direction of the coil portion.

  Next, another coil conductor will be described. FIG. 6A is a plan view of the coil conductor 4b. The coil conductor 4b is not a circle like the coil conductor 4, but a substantially rectangular shape. In this case, it is also called a spiral shape whose diameter changes from the center.

  The coil conductor 4b is composed of a plurality of coil materials 13a to 13d having different sizes. The coil materials 13a to 13d are flat materials. Each of the coil materials 13a to 13d has a bent portion of approximately 90 °. In addition, the coil materials 13 a to 13 d are joined to each other at the joint portion 31. The end of the outermost coil material 13a is joined to the substrate side material 17a. Further, the end portion of the innermost coil material 13d is joined to the substrate side material 17b. The board-side materials 17a and 17b are joined to other circuit materials to constitute a circuit conductor.

  FIG. 6B is a cross-sectional view taken along line BB in FIG. In the joining part 31, each coil raw material is joined by soldering or welding, for example. Further, the end portion of the innermost coil material 13d is wider (higher in height) than other portions, and the portion located above the other coil material is the joint portion 33. At the joint portion 33, the coil material 13d and the substrate side material 17b are joined. By doing in this way, it can prevent that the board | substrate side raw material 17b contacts with another coil raw material.

  Like the coil conductor 4b, the coil conductor 4b can be easily processed by making the shape of the coil substantially rectangular. This is because the dimensional accuracy is higher when the coil material is processed into a rectangle by pressing, compared with the case where the coil material is processed into a circular shape.

  Moreover, each coil material can be made small by joining the coil material which has a some bending part instead of bending one coil material. Therefore, the yield from a board | plate material is good, and productivity can be improved.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs.

  For example, in the example described above, only the transformer 3 has been described, but the present invention can be similarly applied to the choke coil 5. For example, the present invention can be applied even when the width direction of the coil material is substantially perpendicular to the axial direction of the coil. FIG. 7 is a cross-sectional view showing a state in which the circuit conductor 15 is arranged in the mold 19a. In the mold 19a, a groove 23a is provided at a position corresponding to the coil conductor 4a. The groove 23a corresponds to the form of the coil conductor 4a, and the groove interval of the groove 23a corresponds to the interval between the layers in the coil conductor 4a.

In this state, the substrate can be molded by injecting the injection resin 9 into the mold 19a. In this case as well, the coil exposed portion 2 is formed in a part of the choke coil 5, but if insulation is required, an insulating resin or the like may be applied to the coil conductor 4a exposed from the injection resin 9. . In this way, by forming a groove in the mold regardless of the direction of the coil, it is possible to ensure insulation between the coil materials at each turn without using an insulating material that prevents contact between the coil materials. can do.
In the above-described example, the coil conductors 4 and 4a are provided with conductors on a plurality of circumferences, but may be one round, and in this case, the positioning effect can be obtained.

DESCRIPTION OF SYMBOLS 1 ......... Board | substrate 2 ...... Coil exposed part 3 ......... Transformer 4, 4a, 4b ......... Coil conductor 5 ......... Choke coil 7 ......... Electronic component mounting part 8a, 8b, 8c ......... Connection Part 9 ......... Injection resin 11 ......... Heat dissipation parts 13a, 13b, 13c, 13d ......... Coil material 15 ...... Circuit conductors 17a, 17b ...... Substrate side materials 19, 19a ......... Mold 21 ... ...... Cavity 23, 23a ......... groove 25 ......... pin 27 ......... coil center 29 ......... current concentrating part 31, 33 ......... joining part 101 ......... circuit conductors 103a, 103b ......... coil conductor 105 ... Insulating material 107 ... Mold

Claims (8)

Forming multiple circuit materials,
Joining predetermined parts of the circuit materials to form a circuit conductor having a coil portion,
The coil portion is provided in a spiral shape so that the diameter of the flat coil material changes from the center,
The width direction of the coil material is formed so as to be substantially parallel to the axial direction of the coil portion,
When the circuit conductor is set in the injection mold, a part of the coil conductor part of the coil part is formed on the injection mold and spirally formed at a predetermined interval corresponding to the shape of the coil part. The coil conductor part of the coil part is held by being inserted into the groove formed,
Method of manufacturing a substrate, which comprises injection molding a resin to the injection mold in this state. Spiral shape of the coil portion, a manufacturing method of a substrate according to claim 1, characterized in that a substantially rectangular shape. The substrate manufacturing method according to claim 2 , wherein the coil part is formed by joining a plurality of the coil materials having a bent part of approximately 90 °. The substrate manufacturing method according to any one of claims 1 to 3, wherein the coil portion is formed such that an end portion of the innermost coil material is wider than other portions. A circuit conductor having a coil portion and joining predetermined portions of a plurality of circuit materials;
An injection molding resin covering at least a part of the circuit conductor;
Comprising
The coil part is formed in a spiral shape so that the diameter of the flat coil material changes from the center, and the width direction of the coil material is formed so as to be substantially parallel to the axial direction of the coil part,
Injection molding a part of the width direction of the respective coil conductors formed on the coil portion, exposed from the injection-molded resin in a spiral shape at predetermined intervals, the coil exposed portion is formed, characterized in Rukoto substrate. 6. The injection-molded substrate according to claim 5, wherein an insulating resin is applied to the coil exposed portion. The injection-molded substrate according to claim 5 or 6, wherein the coil portion has a substantially rectangular shape, and is formed by joining a plurality of the coil materials having a bent portion of approximately 90 °. The coil part is formed such that the end of the innermost coil material is wider than the other part, and the part located above the other coil material is a joint part with the substrate side material. The injection-molded substrate according to any one of claims 5 to 7, wherein:

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