JP2002134870A - Circuit board for large current, method of manufacturing the board, and composite circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel large-current circuit board which can overcome the problem with an increased board surface caused by an expensive processing of a reinforcing jumper or thick soldering when the board is manufactured, to provide a method for manufacturing the circuit board, and a composite circuit board using the large-current circuit board. SOLUTION: The large-current compact circuit board is obtained by cutting a thin metallic plate member for a metallic conductor circuit into a desired circuit shape while leaving a suitable linkage bridge, masking non-mold surface of the metallic conductor circuit, setting it in a metal die for resin molding, insert-molding it with thermoplastic resin, and then machining it. The large- current circuit board is to be electrically connected with a small-current printed wiring board. The composite circuit board is obtained by electrically connecting these boards not using electrical wire but by mechanical fixing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large current control board incorporating a metal conductor circuit having a large current capacity and a method of manufacturing the same. Further, the large current control board is combined with a printed wiring board having a small current capacity. Composite substrate.

[0002]

2. Description of the Related Art A control circuit board for controlling a power circuit such as a motor drive system of an air conditioner includes a large current control unit composed of a circuit having a large current capacity such as a power supply circuit and a large current control circuit, and a semiconductor chip (IC). ), And a small current control unit mounted with a device having a small current capacity, and forming them on the same circuit board to reduce the size and save the mounting space.

For example, a copper-clad laminate obtained by attaching a thick copper foil to an insulating substrate is pattern-etched using a resist to form a relatively thick large-current circuit, and an upper surface of the circuit is formed via an insulating layer. In order to create a thin, small current circuit, it has been common practice. Further, in order to form a circuit for large current, means such as using a reinforcing jumper or thickly applying solder has been used.

[0004]

However, in the method of etching a copper foil, the thickness of the copper foil to be used is limited to a thickness that can be etched. There was a limit to making the circuit compact. In addition, since the large current circuit and the small current circuit have a laminated structure, if any one of them has a design change,
There is also a problem that the entire circuit on the substrate must be changed, and it is not possible to flexibly respond to a change in design.

[0005] On the other hand, in the case of thick coating of a reinforcing jumper or solder, there is a problem that the operation steps for the thick coating are complicated and the manufacturing cost is increased.

[0006]

SUMMARY OF THE INVENTION The present invention provides a novel board technology which solves such a problem. The first aspect of the present invention is to provide a circuit board which is electrically connected to a small current printed wiring board. A high-current circuit board having a high-current metal conductor circuit, wherein the metal conductor circuit is formed by cutting from the thin metal plate member and then insert-molded with a thermoplastic resin. It is a feature. There, the metal conductor circuit is formed without using a chemical etching process, so that it is compact and of uniform quality having a desired thickness and circuit shape.

According to a second aspect of the present invention, in the first aspect of the present invention, the metal conductor circuit subjected to the insert molding is combined in upper and lower multi-stages. It is possible to make the circuit compact and configure a complicated circuit for large current such as a plurality of power supply circuits.

According to a third aspect of the present invention, in the first or second aspect, a bracket for supporting and fixing the large current circuit board is integrally formed at an end of the large current circuit board. Yes, this allows the fixture for mounting to the control device to be molded simultaneously with the substrate with the same resin as the mold resin, so that it is not necessary to separately form the mounting member as an aluminum bracket.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the high-current electronic component electrically connected to the metal conductor circuit is formed on the resin mold of the high-current circuit board. Since it is mounted and does not contain small-current electronic components, design becomes easy.

In a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the metal sheet member is a copper plate, and may be a copper alloy pre-plated plate.

According to a sixth aspect of the present invention, there is provided a method for manufacturing a large-current circuit board having a large-current metal conductor circuit electrically connected to a small-current printed wiring board, the method comprising: The metal thin plate member is cut into a desired circuit shape, leaving the connecting bridge in place, and the non-molded surface of the metal conductor circuit is subjected to a masking process. , And then a mechanical processing is performed.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the thermoplastic resin is a glass-reinforced polybutylene terephthalate resin.

According to an eighth aspect of the present invention, in the sixth or seventh aspect, the insert molding is performed by a horizontal molding machine, and the ninth aspect of the present invention is the sixth aspect.
In any one of the inventions as set forth in any one of claims 8 to 8, the mechanical processing includes tab bending and cutting of the connecting bridge.

According to a tenth aspect of the present invention, there is provided a composite circuit board comprising the large current circuit board according to the first aspect of the present invention and the small current printed wiring board, wherein the large current circuit board and the small current The small-sized printed wiring board is electrically connected to the small-current printed wiring board by electrically connecting a tap provided from the metal conductor circuit to a terminal of the small-current printed wiring board by a conductive screw member. It is characterized by being performed. Thus, the electrical connection is made by means of a detachable mechanical support.

According to an eleventh aspect of the present invention, there is provided a composite circuit board comprising the large current circuit board according to the first aspect of the present invention and the small current printed wiring board, wherein the large current circuit board and the small current The printed circuit board for soldering is such that the electrical connection is such that the metal conductor cut out from the metal conductor circuit and the connection pin erected from the metal conductor circuit are soldered to the wiring of the printed circuit board for small current. It is characterized in that it is performed by doing. There, electrical connection and mechanical support are made without the use of wires or wiring.

According to a twelfth aspect of the present invention, there is provided a composite circuit board comprising the large current circuit board according to the first aspect of the invention and at least two of the small current printed wiring boards disposed opposite to both front and back surfaces of the board. The electrical connection between the at least two small-current printed wiring boards is performed via a connector inserted and fixed in a through hole provided in the large-current circuit board. is there. Therefore, the electrical connection is made by a rigid fixed wiring member without using an electric wire.

According to a thirteenth aspect of the present invention, there is provided the composite circuit board according to the twelfth aspect of the present invention, wherein the large current circuit board and the one small current printed circuit board are electrically connected to each other. This is performed by detachably connecting a tap provided from a metal conductor circuit and a terminal of the one small-current printed wiring board with a conductive screw member, so that the large-current circuit board and another one are connected. The small-current printed wiring board is configured such that the electrical connection between the metal conductor cut out from the metal conductor circuit and the connection pin erected from the metal conductor circuit is the other small-current printed wiring board. This is characterized by being performed by soldering to the wiring of the substrate. Therefore, in the composite circuit board, electrical connection between the respective boards is performed by using a fixed member instead of an electric wire and also serving as mechanical support.

The invention according to claim 14 is the invention according to claims 10 to 13
In any one of the inventions, the metal conductor circuit insert-molded is combined in upper and lower multi-stages. The invention according to claim 15 is the circuit according to any one of claims 10 to 14, wherein A bracket for supporting and fixing the large-current circuit board is integrally formed at an end of the board.
In any one of the inventions of 0 to 15, the high-current circuit board is provided with a high-current electronic component electrically connected to the metal conductor circuit.

The invention of claim 17 is the invention of claims 10 to 16
In any one of the inventions, the metal sheet member is a copper plate.
In any one of the inventions according to any one of the first to seventeenth aspects, the low-current printed wiring board is provided with a low-current electronic component constituting a low-current control unit.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a large current circuit board and a composite circuit board using the same according to the present invention will be described with reference to FIGS. FIG. 1 shows a composite circuit board 1
1 is a side view (partially sectional view), and FIG. 2 is a plan view seen from below in FIG. 1. For convenience, some components are removed, and the circuit inside the substrate is shown by a solid line. FIG. 3 is a front view as viewed from the left side of FIG. 1, but shows the heat sink 5 removed, and FIG. 4 is a perspective view of the bracket 6 as viewed from below the large current circuit board 2. It is.

In the composite circuit board 1 shown in FIG. 1, the large current circuit board 2 has metal (copper) conductor circuits 7 and 8 formed by punching a copper plate having a predetermined thickness into a circuit shape and arranging them vertically.
It is formed by insert molding with a thermoplastic resin. The printed circuit boards 3 and 4 for small current are
Are opposed to each other, and are electrically connected to each other and are supported and fixed. A resin bracket 6 (see FIGS. 3 and 4) is formed integrally with the composite circuit board 1 at an end (left end in FIG. 1) of the composite circuit board 1. It is fitted and closely attached to the heat sink 5. On the lower surface of the large current circuit board 2, capacitors 16 to 18 having a large current capacity are connected to the metal (copper) conductor circuit 7 at an appropriate position.

Referring now to the plan view of FIG. 2, the capacitors 16 to 18 and the small-current printed wiring board 4
Is indicated by a two-dot chain line, its circuit configuration and contacts with other substrates are omitted, and the lower-level metal (copper) of the large-current circuit board 2 is shown.
The circuit shape of the conductor circuit 8 is indicated by a thick two-dot chain line. As can be seen from this figure, the shape of the insert-molded circuit is formed in a strip shape having a predetermined width in the vertical direction and the horizontal direction, and contacts with electronic components such as resistors, capacitors, diodes, etc. in appropriate places. It is known that they are mounted on the substrate. The copper plate as the metal conductor is a copper alloy pre-plated, and its thickness is 0.64 mm or 0.8 mm depending on the current capacity.

From the large current circuit board 2, for example,
Metal conductive taps 9 to 12 are provided upright, and are electrically connected to the small-current printed wiring board 3 and / or are mechanically fixed. Referring to FIG. 1, the taps 9 to 11 are vertically arranged while making contact with a metal (copper) conductor circuit 7 which is insert-molded, and a female screw portion is provided at the head thereof. Therefore, similarly, these are connected and fixed by screwing with a male screw that makes contact with the small-current printed wiring board 3.

On the other hand, the tap 12 and the female screw to be screwed therewith are not provided with electrical contact from any of the substrates, and are provided merely for mechanically fixing the two substrates. This is because the electrical connection point only by the tap does not always provide a balanced mechanical holding means.

Next, the connection structure between the large current circuit board 2 and the small current printed wiring board 4 thereunder will be described. The tip of the copper plate 13 partially cut and raised from the metal (copper) conductor circuit 7 and the tip of the connection pin 15 that has also made contact with the metal (copper) conductor circuit 7 are connected to the printed circuit board 4 for small current. Soldered in place on the circuit. This is because the small-current printed wiring board 4 is relatively small and has no exchangeability, so that it is preferable to treat it as an integral part of the metal (copper) conductor circuit 7.

Next, the small current printed wiring boards 3 and 4
The interconnection of The large current circuit board 2 is provided with two connectors 14 fitted in the through holes. Each connector 14 has two sides (up and down in FIG. 1).
Is provided, the fixed wiring member 31 is detachably connected thereto. This wiring member 31
Are connected by soldering to appropriate places of the small-current printed wiring boards 3 and 4, respectively. In addition, the electric wire 19
This is a connection wiring to an external device, for example, an input signal from a temperature sensor or the like, or an output wiring to an indicator or the like.

The high-current circuit board and the small-current printed wiring board provided separately from the high-current circuit board are connected to each other without using an electric wire, and the electrical or mechanical connection between them is detachable. Or soldering.

Next, an embodiment of a method of manufacturing a circuit board for a large current will be described with reference to FIGS. FIG. 5 is a longitudinal sectional view showing a state where the punched copper plate 27 is set in the mold 28. FIG. 6 is a partially enlarged perspective view. 0.64 thickness as a thin metal plate
mm copper alloy pre-plated plate, bridge 2 in place
A copper plate circuit connected by 5 is punched out by a press machine, vacuum-sucked as one copper plate 27, and set in a horizontal molding machine for insert molding. For this set, fitting holes 26 are punched in place in the copper plate circuit at the time of punching, while the mold 28 of the horizontal molding machine is provided with:
A plurality of engaging projections 29 to be inserted into the fitting holes 26 are provided. Also, to form a non-molded surface on the copper plate circuit,
A masking process is performed at that location. The non-molded surface is a portion where it is desirable to previously expose the copper plate surface, such as a portion for making contact with an electronic component to be mounted, a tab to be bent, and a connector through hole. After setting, the molding resin is poured into the mold. As the resin material, a thermoplastic resin such as polybutylene terephthalate (PBT) -based resin or polyphenylene sulfide-based resin having a glass reinforcement of 30% is preferable.

Also, when forming the mold, the bracket 6 is simultaneously formed integrally. After molding, the runner and the molded circuit board 2 are taken out by a take-out machine of a molding machine, and tab bending and cutting and removal of the bridge 25 are performed. These mechanical processings are performed at once by a press machine, or Performed separately. Then, using a robot, high-current electronic components such as a capacitor, a power FET, and a resistor are soldered. In this soldering, holes having tapered portions for mounting components and soldering are formed on the lower surface side of the molded circuit board 2 and the electronic components are inserted and fixed from the lower surface side, and the soldering from the upper surface side is performed. It is done by attaching.

In the above embodiment, the metal sheet member is
Although a copper plate was used, the present invention is not limited to this,
Aluminum, a laminate with another metal, or the like can be used. In addition, not only one small current printed wiring board may be disposed apart from the front and back surfaces of the large current circuit board, but also a plurality of separate printed wiring boards may be provided at the same distance, Such a printed wiring board can be configured in upper and lower stages. In this case, tap 9
Such taps can be provided between printed wirings, and such taps can be formed long so as to correspond to a two-step distance so that they can be directly connected from a large current circuit board. Further, the large-current circuit board is not limited to the configuration of a single board, but can be provided in multiple stages as in the case of the printed wiring board. In addition, the required connection can be made after separately performing insert molding and then laminating the metal (copper) conductor circuits 7 and 8 without combining and molding them at the same time.

[0031]

According to the large current circuit board and the method of manufacturing the same of the present invention, a metal conductor circuit obtained by cutting a copper plate having a desired thickness into a circuit shape is used, so that the circuit area can be reduced, and thus a more compact circuit board can be obtained. Can be Also, compared to the conventional thick soldering or reinforcing jumper, the circuit forming process is simplified, and the product is a low-cost product suitable for uniform quality and mass production. Furthermore, at the same time, this metal conductor circuit is insert-molded independently of (separately from) the low-current printed wiring, so that the subsequent mounting process of the electronic components is more complicated than the complicated process of forming on the same substrate. Because it is created by an easy process including
It is possible to flexibly cope with a design change of a printed wiring board. In addition, a bracket that is tightly fixed to the heat sink can also be formed when forming the insert mold,
Further, by forming the metal conductor circuit itself in multiple stages, it is possible to cope with a more complicated circuit configuration.

The composite circuit board of the present invention combines the above-described large-current circuit board with a separate small-current printed circuit board. In the case of adopting a structure which serves both as an electrical connection and a mechanical support, the connection can be made detachable. Further, since the respective boards can be connected to each other without using a wiring material such as an electric wire, the entire board is simplified and the assembling process is also facilitated.

[Brief description of the drawings]

FIG. 1 is a side view of a large current circuit board according to an embodiment of the present invention and a composite circuit board using the same.

FIG. 2 is a view of the large current circuit board of FIG. 1 viewed from below;
It is the simplified top view.

FIG. 3 is a front view of the composite circuit board of FIG. 1 as viewed from the left.

FIG. 4 is a perspective view of the bracket side from the lower side of the large current circuit board of FIG. 1;

FIG. 5 is a vertical cross-sectional view for explaining setting to a mold in the method for manufacturing a large current circuit board according to one embodiment of the present invention.

FIG. 6 is a partially enlarged perspective view of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Composite circuit board, 2 ... Large current circuit board, 3 and 4 ...
Printed wiring board for small current, 5 heat sink, 6 bracket, 7 and 8 metal (copper) conductor circuit, 9 to 12
... Tap, 13 ... Copper plate (cut and raised), 14 ... Connector, 15 ... Connecting pin, 25 ... Bridge, 26 ... Fit hole,
27: copper plate (circuit), 28: mold, 29: engagement projection, 3
1. Wiring member.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (18)

[Claims] 1. A large-current circuit board having a large-current metal conductor circuit electrically connected to a small-current printed wiring board, wherein the metal conductor circuit is cut from the metal sheet member. A circuit board for large current, characterized by being molded by a thermoplastic resin and then insert-molded with a thermoplastic resin. 2. The circuit board for a large current according to claim 1, wherein said metal conductor circuits subjected to insert molding are combined in upper and lower stages. 3. The large-current circuit board according to claim 1, wherein a bracket for supporting and fixing the large-current circuit board is integrally formed at an end of the large-current circuit board. . 4. The large current according to claim 1, wherein a large current electronic component electrically connected to said metal conductor circuit is mounted on a resin mold of said large current circuit board. Circuit board. 5. The large current circuit board according to claim 1, wherein said metal sheet member is a copper plate. 6. A method for manufacturing a large-current circuit board having a large-current metal conductor circuit electrically connected to a small-current printed wiring board, comprising the steps of: , Cut into a desired circuit shape, leaving the connecting bridge in place, mask the non-molded surface of the metal conductor circuit, set it in a resin mold, and insert mold with thermoplastic resin And then
A method for manufacturing a large-current circuit board, comprising performing mechanical processing. 7. The method according to claim 6, wherein the thermoplastic resin is a glass reinforced polybutylene terephthalate resin or a glass reinforced polyphenylene sulfide resin. 8. The method according to claim 6, wherein, when performing the insert molding, the cut metal conductor circuit is set in the resin molding die provided in the horizontal molding machine by a take-out machine. A method for manufacturing the circuit board for high current according to the above. 9. The method for manufacturing a large current circuit board according to claim 6, wherein said mechanical processing includes tab bending and cutting of said connecting bridge. 10. A composite circuit board comprising the circuit board for large current according to claim 1 and the printed circuit board for small current, wherein the circuit board for large current and the printed circuit board for small current are provided. Is characterized in that their electrical connection is made by detachably connecting a tap provided from the metal conductor circuit and a terminal of the small current printed wiring board by a conductive screw member. Composite circuit board. 11. A composite circuit board comprising the circuit board for large current according to claim 1 and the printed circuit board for small current, wherein the circuit board for large current and the printed circuit board for small current are provided. The electrical connection is performed by soldering the metal conductor cut out from the metal conductor circuit and the connection pin erected from the metal conductor circuit to the wiring of the small current printed wiring board. A composite circuit board characterized by the above. 12. A composite circuit board comprising: the high-current circuit board according to claim 1; and at least two small-current printed wiring boards arranged opposite to both front and back surfaces of the board. A composite circuit board, wherein the electrical connection between the two small-current printed circuit boards is made via a connector inserted and fixed in a through hole provided in the large-current circuit board. 13. The composite circuit board according to claim 12, wherein the large-current circuit board and one of the small-current printed circuit boards are electrically connected to each other from the metal conductor circuit. It is performed by detachably connecting the provided tap and the terminal of the one small current printed circuit board by a conductive screw member, and the large current circuit board and the other small current printed circuit are connected. The wiring board is configured such that the electrical connection between the metal conductor and the connection pin formed from the metal conductor circuit is formed by soldering the metal conductor cut from the metal conductor circuit to the wiring of the other small current printed wiring board. A composite circuit board characterized by being attached. 14. The composite circuit board according to claim 10, wherein said insert-molded metal conductor circuits are combined in upper and lower stages. 15. The composite circuit board according to claim 10, wherein a bracket for supporting and fixing said large current circuit board is integrally formed at an end of said large current circuit board. . 16. The composite circuit board according to claim 10, wherein said high-current circuit board has a high-current electronic component electrically connected to said metal conductor circuit. 17. The composite circuit board according to claim 10, wherein said thin metal plate member is a copper plate. 18. The printed circuit board for small current,
The composite circuit board according to any one of claims 10 to 17, further comprising a small-current electronic component constituting a small-current control unit.