WO2018193828A1

WO2018193828A1 - Metal member-equipped substrate, circuit structure, and electrical connection box

Info

Publication number: WO2018193828A1
Application number: PCT/JP2018/014205
Authority: WO
Inventors: 幸貴内田; 北　幸功
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2017-04-18
Filing date: 2018-04-03
Publication date: 2018-10-25
Also published as: JP2018182148A

Abstract

A metal member-equipped substrate 21 is provided with: an insulated substrate 22 which has formed therein a substrate through-hole 25 and an electrically-conducting path 24 formed in an insulation plate 23; a bus bar 28 which is stacked on the insulated substrate 22 and which has formed therein a bus bar through-hole 29 contiguous to the substrate through-hole 25; a metal member 30 which has a shaft part 31 and a first head part 32 having a diameter larger than that of the shaft part 31; and a conductive joining member 35 which, while one of the shaft part 31 and the first head part 32 is kept inserted in the substrate through-hole 25, joins the inner wall of the substrate through-hole 25 with said one of the shaft part 31 and the first head part 32, wherein the other of the shaft part 31 and the first head part 32 is fixed to the bus bar 28 while being kept inserted in the bus bar through-hole 29.

Description

Substrate with metal member, circuit structure, and electrical junction box

In this specification, the technique regarding the board | substrate with a metal member is disclosed.

Conventionally, a technique in which a metal member is attached to a through hole of a board and a bus bar is known. The circuit configuration body of Patent Document 1 includes a printed circuit board in which a rectangular positioning through hole is formed, and a bus bar that is stacked on the printed circuit board and has a rectangular bus bar through hole. The inlay press-fitted into the bus bar is press-fitted into the positioning through hole of the printed circuit board and the bus bar through hole of the bus bar.

Japanese Unexamined Patent Publication No. 2015-46479

By the way, in the configuration in which the inlay is press-fitted into both the positioning through hole of the printed circuit board and the bus bar through hole of the bus bar as in Patent Document 1, the positioning through hole, the bus bar through hole, and the inlay have high accuracy. Since it is required, there is a problem that the manufacturing cost tends to be high.

The technology described in the present specification has been completed based on the above-described circumstances, and aims to reduce the manufacturing costs of the substrate with metal member, the circuit structure, and the electrical junction box.

The substrate with a metal member described in this specification includes an insulating substrate in which a conductive path is formed in an insulating plate and a substrate through hole is formed, and a bus bar through hole that is overlapped with the insulating substrate and is continuous with the substrate through hole. And a metal member having a shaft portion and a first head having a diameter larger than the diameter of the shaft portion, and one of the shaft portion and the first head is the substrate. A conductive bonding material that joins the one side and the inner wall of the substrate through hole in a state of being inserted through the through hole, and the other of the shaft portion and the first head is the bus bar penetrating The bus bar is fixed in a state of being inserted into the hole.

According to the above configuration, since one of the shaft portion and the first head portion and the inner wall of the substrate through-hole are joined by the conductive joining material, for example, the shaft portion and the first head portion are only pressed. Compared with the configuration in which one of the two is connected to the inner wall of the substrate through-hole, high dimensional accuracy is not necessarily required, so that the manufacturing cost can be reduced. In addition, the metal member is fixed to the bus bar while the other of the shaft portion and the first head is inserted into the bus bar through hole, so that a relatively large current is generated in the conductive path of the insulating substrate. Therefore, it is possible to suppress the heat generation and the deterioration of the efficiency of the insulating substrate, and it is possible to improve the positional accuracy in the thickness direction of the insulating substrate in the metal member. Further, since the metal member has the first head, it is possible to easily align the shaft portion in the insertion direction with respect to the substrate through hole and the bus bar through hole, and the metal member has the first head. Since the heat capacity of the metal member can be increased as compared with the case where there is no portion, the heat dissipation through the metal member can be improved.

The following embodiments are preferable as the embodiments of the technology described in this specification.
The end surface of the metal member on the insulating substrate side is formed at the same height as the surface of the conductive path on which the electronic component is mounted on the insulating substrate.
In this way, the step between the surface on which the electronic component is mounted in the conductive path of the insulating substrate and the end surface of the metal member is suppressed, so that the inclination of the electronic component on the insulating substrate is less likely to occur. Electronic component mounting defects can be reduced.

The metal member includes a second head having a diameter larger than the diameter of the shaft portion on a side opposite to the first head side.
If it does in this way, even if it does not press-fit a metal member in a bus-bar through-hole, for example, a metal member can be fixed to a bus-bar.

It is set as a circuit structure provided with the said board | substrate with a metal member, the electronic component connected to the said metal member, and the thermal radiation member piled up on the said board | substrate with a metal member.
In this way, the heat of the electronic component can be radiated by the heat radiating member.

A heat transfer material disposed between the metal member and the heat radiating member; and a spacer portion that maintains a space between the bus bar and the heat radiating member.
If it does in this way, the heat of an electronic component can be transmitted to a heat radiating member via a metal member and a heat transfer material, and can be radiated to the exterior from a heat radiating member.

Suppose that it is an electrical connection box provided with the said circuit structure and the case which covers the said circuit structure.

According to the technique described in this specification, it becomes possible to reduce the manufacturing cost of the substrate with metal member, the circuit structure, and the electrical junction box.

Sectional drawing which shows the electrical-connection box of Embodiment 1. 1 is an enlarged cross-sectional view of a part of FIG. Perspective view showing metal member Side view showing metal parts Perspective view showing metal member before caulking to bus bar Side view showing metal member before caulking to bus bar Bottom view showing metal parts before caulking to busbar Sectional drawing which shows the state by which the axial part of the metal member was penetrated by the bus-bar through-hole Sectional drawing which shows the state which crimped the metal member and was made to adhere to a bus-bar Sectional drawing which shows the state which piled up the insulation board | substrate on the bus-bar which the metal member of FIG. 9 adhered. Sectional drawing which shows the state by which the axial part of the metal member of Embodiment 2 was press-fit in the bus-bar through-hole.

<Embodiment 1>
The first embodiment will be described with reference to FIGS.
The electrical junction box 10 is arranged in a power supply path between a power source such as a battery of a vehicle and a load composed of an on-vehicle electrical component such as a lamp and a wiper or a motor, and is used for, for example, a DC-DC converter or an inverter. be able to. The electrical junction box 10 can be arranged in any direction. In the following description, the Y direction in FIG.

(Electric junction box 10)
As shown in FIG. 1, the electrical junction box 10 includes a circuit structure 20 and a case 11 that covers the circuit structure 20. The case 11 has a box shape with an opening on the lower side, and includes a main body 12 made of metal or synthetic resin such as aluminum or aluminum alloy, and a connector housing 13 made of synthetic resin. The connector housing 13 includes a hood portion 14A that opens in the form of a hood and a back wall portion 14B that closes the hood portion 14A. It protrudes into the part 14A.

(Circuit structure 20)
The circuit component 20 includes a substrate 21 with a metal member and a heat radiating member 40 that is disposed under the substrate 21 with a metal member and radiates the heat of the substrate 21 with the metal member to the outside.

(Substrate with metal member 21)
The substrate 21 with a metal member includes an insulating substrate 22, a plurality of bus bars 28 stacked on the insulating substrate 22, and a plurality of metal members 30 attached to the insulating substrate 22 and the plurality of bus bars 28.
(Insulating substrate 22)
The insulating substrate 22 has an insulating plate 23 made of an insulating material and a conductive path 24 made of copper foil or the like formed on the upper surface of the insulating plate 23 by a printed wiring technique. The insulating substrate 22 is not limited to this, and for example, a multilayer substrate may be used. The insulating substrate 22 is formed with a perfectly circular substrate through hole 25 penetrating in the vertical direction (plate thickness direction). In this embodiment, the conductive path 24 is not formed in the hole wall of the substrate through hole 25, and is electrically connected to the conductive path 24 such as the upper surface of the insulating substrate 22 by a conductive bonding material 35 described later. However, the present invention is not limited to this. For example, a conductive path connected to the conductive path 24 such as the upper surface of the insulating substrate 22 may be formed on the entire hole wall of the substrate through hole 25 by copper foil or the like.

(Bus bar 28)
The plurality of bus bars 28 include a bus bar main body 28A that overlaps the insulating substrate 22, and an L-shaped bus bar terminal portion 28B that rises from an edge of the bus bar main body 28A. A bus bar through hole 29 having a perfect circle shape is formed through the bus bar main body 28 A at a position continuing below the substrate through hole 25.

An electronic component 27 as a heat generating component is mounted on the conductive path 24 and the metal member 30 of the insulating substrate 22. The electronic component 27 has a flat rectangular parallelepiped main body 27A and a plurality of terminals 27B formed on the bottom surface of the main body 27A. The lower surfaces of the plurality of terminals 27 B are formed on the same plane as each other, and are connected to lands as conductive paths 24 formed on the surface of the insulating substrate 22. The plurality of terminals 27 B of the electronic component 27 according to the present embodiment are soldered to the conductive path 24 (land) on the upper surface of the substrate 22 and the upper end surface 32 A of the metal member 30. In the present embodiment, the electronic component 27 is an FET (Field Effect Transistor), but may be a heat generating component such as a resistor, a coil, or a capacitor.

(Metal member 30)
The metal member 30 is made of metal such as copper, copper alloy, aluminum, aluminum alloy, iron, and stainless steel, for example, and as shown in FIGS. 3 and 4, a cylindrical shaft portion 31 and an upper portion of the shaft portion 31. Provided on the side (one side in the axial direction) and having a columnar first head 32 having a diameter larger than the diameter of the shaft portion 31, and on the lower side (the other side in the axial direction) of the shaft portion 31. And a columnar second head 33 having a diameter larger than the diameter of the shaft portion 31. In this embodiment, the metal member 30 is a rivet.

The shaft part 31 has a diameter smaller than the hole diameter of the bus bar through hole 29. As shown in FIG. 2, the first head 32 has a diameter B1 that is smaller than the hole diameter A1 of the substrate through hole 25, and when the first head 32 is inserted into the substrate through hole 25, A gap is formed between the outer peripheral surface of the first head portion 32 and the hole wall of the substrate through hole 25, and solder as the bonding material 35 is disposed in this gap. Since the length of the first head 32 in the vertical direction (axial direction) is the same as the thickness of the insulating substrate 22, the upper end surface 32 A of the first head 32 and the upper surface of the insulating substrate 22 are electrically conductive. The path 24 is arranged on the same plane.

The second head 33 has a diameter smaller than the diameter of the first head 32. The hole edge portion of the bus bar through hole 29 on the upper and lower surfaces of the bus bar 28 is sandwiched between the lower end edge of the first head portion 32 and the upper end edge of the second head portion 33, so that the metal member 30 is fixed to the bus bar 28. Has been. 5A and 5B, the metal member 30A before the metal member 30 is fixed to the bus bar 28 has a first head portion 32 and a shaft portion 31A, and a second head portion 33 is formed. It has not been. The second head portion 33 is formed by caulking and deforming the distal end side of the shaft portion 31A.

As shown in FIG. 2, a heat transfer material 36 is disposed between the second head 33 and the upper surface 40 A of the heat radiating member 40. For the heat transfer material 36, for example, a material having high thermal conductivity such as silicone grease and having insulating properties is used. The heat transfer material 36 is disposed so as to include the entire region where the second head 33 and the upper surface 40A of the heat radiating member 40 overlap. The heat of the metal member 30 is transmitted to the heat radiating member 40 through the heat transfer material 36 and is radiated from the heat radiating member 40 to the outside.

(Heat dissipation member 40)
The heat dissipating member 40 is made of a metal having high thermal conductivity such as aluminum or aluminum alloy, and has a flat upper surface 40A as shown in FIG. The heat radiation fin 41 is provided. A plurality of spacer portions 42 projecting upward are provided near the periphery of the upper surface 40 A of the heat radiating member 40. An insulating layer 44 made of, for example, an insulating adhesive is formed on the spacer portion 42. The insulating layer 44 insulates the insulating substrate 22 from the spacer portion 42. The end of the bus bar main body 28 A on the bus bar terminal portion 28 B side is placed on the spacer portion 42, thereby maintaining a predetermined distance between the lower surface of the bus bar 28 and the upper surface 40 A of the heat dissipation member 40.

Next, a method for manufacturing the circuit structure 20 will be described.
As shown in FIG. 8, when the shaft portion 31A of the metal member 30A is inserted into the bus bar through-hole 29 and the tip portion of the shaft portion 31 is caulked and deformed using a jig or the like, as shown in FIG. The second head 33 is formed, and the metal member 30 is fixed to the bus bar 28. Next, as shown in FIG. 10, when the insulating substrate 22 is overlapped on the bus bar 28 and the first head portion 32 is inserted into the substrate through hole 25, the upper end surface 32 A of the metal member 30 and the upper surface of the insulating substrate 22 are It is flush with the conductive path 24.

Next, the insulating substrate 22 and the metal member 30 are bonded to each other by filling the gap between the first head portion 32 and the hole wall of the substrate through hole 25 with the bonding material 35. Specifically, for example, the solder paste is applied to the outer peripheral surface of the first head 32 and the hole wall of the substrate through hole 25, and the insulating substrate 22 and the metal member 30 are bonded by reflow soldering. Can be joined with solder. At this time, solder paste is also applied to the upper end surface 32A of the metal member 30 and the conductive path 24 of the insulating substrate 22, and the electronic component 27 is soldered to the conductive path 24 of the insulating substrate 22 and the metal member 30. The reflow soldering of the terminal 27B of the electronic component 27 and the reflow soldering of the metal member 30 to the board through hole 25 can be performed in the same process, but may be performed in different processes. Note that the joining by the joining material 35 is not limited to reflow soldering. For example, solder melted in a liquid may be put in the gap between the hole wall of the substrate through hole 25 and the metal member 30 to solidify the solder.
Thereby, the board | substrate 21 with a metal member in which the electronic component 27 was mounted is formed.

Then, when the heat transfer material 36 is applied to the position where the metal member 30 is disposed on the upper surface 40 A of the heat dissipation member 40 and the bus bar 28 is disposed on the spacer portion 42 of the heat dissipation member 40, the metal member 30 is placed on the heat transfer material 36. The second head 33 is placed. Then, when the heat radiating member 40 and the insulating substrate 22 are fixed by fixing means such as screws (not shown), the circuit component 20 is formed, and the circuit junction 20 is covered with the case 11 to form the electrical junction box 10 (see FIG. 1).

According to this embodiment, the following operations and effects are achieved.
The substrate 21 with a metal member has an insulating substrate 22 in which a conductive path 24 is formed in the insulating plate 23 and a substrate through hole 25 is formed, and a bus bar through hole 29 that is overlapped with the insulating substrate 22 and is connected to the substrate through hole 25. The metal member 30 having the bus bar 28 formed, the shaft portion 31 and the first head portion 32 having a diameter larger than the diameter of the shaft portion 31, and the first head portion 32 (shaft portion) in the substrate through hole 25. And a conductive bonding material 35 that bonds the first head 32 (one) and the inner wall of the substrate through hole 25 in a state where one of the first head 31 and the first head 32 is inserted. The portion 31 (the other of the shaft portion 31 and the first head portion 32) is fixed to the bus bar 28 while being inserted into the bus bar through hole 29.

According to the present embodiment, the first head portion 32 (one of the shaft portion 31 and the first head portion 32) and the inner wall of the substrate through hole 25 are joined by the conductive joining material 35. For example, a high dimensional accuracy is necessarily required as compared with a configuration in which the first head 32 (one of the shaft portion 31 and the first head 32) and the inner wall of the substrate through hole 25 are connected only by press-fitting. Therefore, the manufacturing cost can be reduced. Further, the metal member 30 has a shaft portion 31 (the other of the shaft portion 31 and the first head portion 32) fixed to the bus bar 28 while being inserted into the bus bar through hole 29, so that Since a large current can flow through the bus bar 28 instead of the conductive path 24 of the insulating substrate 22, it is possible to suppress the heat generation and the deterioration of efficiency of the insulating substrate 22, and the insulating substrate 22 in the metal member 30. The positional accuracy in the thickness direction can be improved. Furthermore, since the metal member 30 has the first head portion 32, it is possible to easily align the shaft portion 31 in the insertion direction with respect to the substrate through hole 25 and the bus bar through hole 29, and the metal member. Since the heat capacity of the metal member 30 can be increased as compared with the case where the first head 32 is not provided in 30, the heat dissipation through the metal member 30 can be improved.

Further, the end surface 32A on the insulating substrate 22 side of the metal member 30 is formed at the same height as the surface of the conductive path 24 on which the electronic component 27 is mounted on the insulating substrate 22.
In this way, the step between the surface on which the electronic component 27 is mounted in the conductive path 24 of the insulating substrate 22 and the end surface 32A of the metal member 30 is suppressed, so that the electronic component 27 on the insulating substrate 22 is suppressed. Inclination or the like is less likely to occur, and mounting defects of the electronic component 27 can be reduced.

Further, the metal member 30 includes a second head 33 having a diameter larger than the diameter of the shaft portion 31 on the side opposite to the first head 32.
In this way, the metal member 30 can be fixed to the bus bar 28 without pressing the metal member 30 into the bus bar through hole 29, so that the manufacturing cost can be reduced.

In addition, the circuit configuration body 20 includes a substrate 21 with a metal member, an electronic component 27 connected to the metal member 30, and a heat dissipation member 40 stacked on the substrate 21 with a metal member.
In this way, the heat of the electronic component 27 can be radiated by the heat radiating member 40.

In addition, a heat transfer material 36 disposed between the metal member 30 and the heat radiating member 40 and a spacer portion 42 that maintains a space between the bus bar 28 and the heat radiating member 40 are provided.
In this way, the heat of the electronic component 27 can be transmitted to the heat radiating member 40 via the metal member 30 and the heat transfer material 36 and radiated from the heat radiating member 40 to the outside.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to FIG. The metal member 50 of the second embodiment does not have the second head 33 in the first embodiment, and the shaft portion 51 is press-fitted into the bus bar through hole 29. Since other configurations are the same as those in the above embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The shaft portion 51 of the metal member 50 has a columnar shape and has substantially the same diameter as that of the bus bar through hole 29 and is press-fitted into the bus bar through hole 29. The axial length of the shaft portion 51 is substantially the same as the thickness of the bus bar 28, and the metal member 30 is obtained when the insulating substrate 22 is overlaid on the bus bar 28 and the first head 32 is inserted into the substrate through hole 25. The upper end surface 32 A and the conductive path 24 on the upper surface of the insulating substrate 22 are flush with each other. A heat transfer material 36 is disposed between the lower end surface of the shaft portion 51 and the upper surface 40 A surface of the heat radiating member 40, and the heat of the metal member 50 is radiated to the outside via the heat transfer material 36 and the heat radiating member 40. Is done.

<Other embodiments>
The technology described in the present specification is not limited to the embodiments described with reference to the above description and the drawings. For example, the following embodiments are also included in the technical scope of the technology described in the present specification.
(1) The electronic component 27 is provided with the terminal 27B on the bottom surface of the main body 27A. However, the electronic component 27 is not limited thereto. For example, the electronic component 27 is an electronic component having a terminal protruding from the side surface of the main body 27A. The terminal may be soldered to the conductive path 24 or the metal member 30. Further, the end of a conductor such as a shunt resistor or a coil may be soldered to the conductive path 24 or the metal member 30.

(2) The first head 32 and the second head 33 of the metal member 30 are disk-shaped, but are not limited thereto. The first head and the second head may be, for example, hemispherical, spherical, rectangular parallelepiped or the like.
(3) The bonding material 35 is solder, but is not limited thereto. For example, a brazing material or a conductive adhesive (conductive resin) may be used as the bonding material 35.

(4) The number of electronic components 27, metal members 30, bus bars 28, etc. is not limited to the number in the above embodiment, and can be changed as appropriate.
(5) Although the metal member 30 is a rivet, the present invention is not limited to this. For example, the metal member 30 may be a screw having a screw portion formed on a shaft portion.

(6) The bus bar 28 and the metal member 30 may be the same metal or different metals. When different metals are used, for example, the bus bar 28 may be aluminum or an aluminum alloy, and the metal member 30 may be copper or a copper alloy.
(7) In the above embodiment, the first head 32 is inserted into the substrate through-hole 25 and the shaft portion 31 (51) is fixed to the bus bar 28. However, the present invention is not limited to this, and the shaft portion 31 ( 51) may be inserted into the substrate through hole 25 and the first head 32 may be fixed to the bus bar 28.

10: Electrical connection box 11: Case 20: Circuit component 21: Substrate with metal member 22: Insulating substrate 23: Insulating plate 24: Conductive path 25: Substrate through hole 27: Electronic component 27B: Terminal 28: Bus bar 29: Bus bar through Holes 30 (30A), 50: Metal members 31 (31A), 51: Shaft portion 32: First head portion 32A: Upper end surface 33: Second head portion 35: Bonding material 36: Heat transfer material 40: Heat dissipation member 40A: Upper surface 42: Spacer portion

Claims

An insulating substrate having an insulating plate in which a substrate through hole is formed and a conductive path formed in the insulating plate;
A bus bar which is stacked on the insulating substrate and has a bus bar through hole connected to the substrate through hole;
A metal member having a shaft portion and a first head portion having a diameter larger than the diameter of the shaft portion;
A conductive bonding material for bonding the one and the inner wall of the substrate through hole in a state where one of the shaft portion and the first head is inserted through the substrate through hole;
The other of the shaft portion and the first head is a substrate with a metal member fixed to the bus bar in a state of being inserted through the bus bar through hole.
2. The substrate with a metal member according to claim 1, wherein an end surface of the metal member on the insulating substrate side is formed at the same height as a surface of a conductive path on which electronic components of the insulating substrate are mounted.
The said metal member is a board | substrate with a metal member of Claim 1 or Claim 2 provided with the 2nd head which has a larger diameter than the diameter of the said axial part on the opposite side to the said 1st head side.
A circuit structure provided with the board | substrate with a metal member as described in any one of Claims 1-3, the electronic component connected to the said metal member, and the thermal radiation member piled up on the said board | substrate with a metal member.
A heat transfer material disposed between the metal member and the heat dissipation member;
The circuit structure according to claim 4, further comprising a spacer portion that maintains a space between the bus bar and the heat dissipation member.
The circuit structure according to claim 4 or claim 5,
An electrical junction box comprising a case that covers the circuit structure.