JPH11163476A - Heat-radiation structure of circuit board and power source control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure sufficient heat-radiation, even with a circuit board of high- density mounting by providing a heat-radiation plate, wherein a heat-generating part of a heat-generating unit is jointed to a part which is not jointed to a printed board directly or through a heat-transfer sheet or silicone grease, etc. SOLUTION: A printed board 12 is a size which is smaller than a heat- radiation plate 11, while a periphery 11a of the heat-radiation plate 11 is stripped, and an IPS and a heat-radiation part 8a of a heat-radiation unit 8 such as a transistor are fixed to the periphery 11a directly or with a heat- transfer sheet or silicon grease, etc., using a rivet or a screw. A lead 8b of the heat-generating unit 8 is connected to a circuit pattern formed on the printed board 12. Since a heat-generating unit is jointed to a heat-radiation plate which is jointed to a printed board, the heat generated at the heat-generating unit is surely radiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiating structure of a circuit board and a power supply control device for radiating heat generating components used in the fields of automobiles and home electric appliances, and more particularly to a high-density mounted circuit. The present invention relates to a heat dissipation structure of a circuit board and a power supply control device capable of securing sufficient heat dissipation even for a board.

[0002]

2. Description of the Related Art In recent years, the number of electric components mounted on automobiles has been increasing in order to improve safety and comfort. Along with this, power supply control devices that distribute and control power supply to electrical components have been bloated. As shown in FIG. 13, this power supply control device has a configuration in which a large current unit 3 and a control circuit unit 4 are housed in a space closed by an upper case 1 and a lower case 2. The large current section 3 is composed of a bus bar section 5 serving as a path for a large current, and a heat generating component such as a current switching element such as a relay 6 or a semiconductor device 7 for switching a large current. In the control circuit unit 4, the small current and the control signal are processed.

Since the bus bar portion 5 itself is a good heat conductor, it plays a role of releasing heat generated by the heat-generating components. However, since the bus bar portion 5 is made by punching a copper plate having a thickness of about 1 mm, it cannot be processed very finely. Therefore, with the increase in the number of circuits, the large current portion 3 has a multilayer structure, and the total thickness of the relay box placed near the battery is about 10 to 15 mm, so that both the volume and the weight occupy a considerable ratio in the entire device. It has become.

[0004] However, the enlargement of the power supply control device in this way hinders the improvement of the livability in the automobile. Therefore, Japanese Patent Laid-Open No. 2-178 discloses an electrical junction box having good heat conductivity and suitable for small size, light weight and high density.
No. 18 and Japanese Utility Model Laid-Open No. 3-70009.

When the busbar section 5 is abolished to reduce the thickness and the function is realized by a normal printed wiring board, the heat dissipation effect of the relay 6 or the like is low because the normal printed wiring board has a small heat radiation effect. There is a problem with the heat radiation measures of the parts. Therefore, a printed wiring board capable of efficiently dissipating heat by providing a new heat dissipation pattern in a blank portion of a laminated board is disclosed in Japanese Utility Model Laid-Open No. 1-161355.

[0006]

Problems to be Solved by the Invention
The electric connection box disclosed in the above publication is characterized in that a printed circuit board containing a metal core is used for wiring of an internal circuit. A connection terminal for connecting components such as a relay is fixed to an end or an intermediate portion of the wiring of the internal circuit by soldering or the like. Therefore, no penetrating components can be used on this printed circuit board, and all components are surface-mounted on the printed circuit board. However, since the connection strength is reduced in the surface mounting, there is a problem that connection reliability of a large current is lacking. In addition, since heat is diffused to the entire metal plate, there is also a problem that the temperature of a portion, such as a CPU and a transmission circuit, where heat is not to be transmitted becomes high.

The electric connection box disclosed in Japanese Utility Model Laid-Open Publication No. 3-70009 discloses that one end of a heat radiating plate is brought into contact with a bus bar portion, and the other end of the heat radiating plate is projected outside from a wall surface of an insulating case. It is a feature. However, this electrical junction box improves the heat dissipation structure of the bus bar,
No consideration is given to a wiring board on which a circuit pattern for weak current wiring is formed.

The printed wiring board disclosed in Japanese Utility Model Laid-Open Publication No. 1-161355 has a heat radiation pattern for dissipating heat of a heat-generating component at a portion other than a conductor pattern for electrically connecting electronic components on a laminate. Is provided. The heat generating component is attached to the through hole, and the heat generated from the heat generating component is efficiently radiated by the heat radiation pattern. However, when the number of heat-generating components increases due to high-density mounting, the heat-radiating pattern is covered by the heat-generating components, and heat cannot be sufficiently released. Therefore, this printed wiring board has problems in heat dissipation performance and board design.

Furthermore, a method has been invented in which after the heat-generating component is soldered to the printed wiring board, the heat-generating component is directly fixed to the housing so that heat can be radiated from the housing. However, in this method, the heat-generating component may be damaged due to the tightening force when fixing the heat-generating component to the housing, the difference in the thermal expansion coefficient between the printed wiring board and the housing, and the influence of external vibration. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a circuit board heat dissipation structure and a heat dissipation structure capable of securing sufficient heat dissipation even in a high-density circuit board. It is an object to provide a power supply control device.

[0011]

A heat radiation structure for a circuit board according to the present invention comprises a printed circuit board having a circuit pattern connected to a lead portion of a heat-generating component, a printed circuit board, and a printed circuit board. And a heat radiating plate for joining the heat radiating portion of the heat generating component directly or with a heat transfer sheet or silicon grease interposed therebetween in a portion not formed.

According to the present invention, the heat generated by the heat generating component is transferred to the heat radiating plate by joining the heat radiating portion of the heat generating component to the heat radiating plate. The heatsink is the same as or slightly larger than the printed circuit board, and the heat transferred to the heatsink is completely radiated.
When the upper case and the lower case are joined to the heat sink or the printed circuit board at the portion where the through hole is formed, the heat transferred to the heat sink is radiated from the upper case and the lower case.

The heat radiating portion of the heat generating component is joined around and / or inside the heat radiating plate, and the printed circuit board has a slightly smaller size and / or size to expose the periphery of the heat radiating plate joined to the heat radiating plate of the heat generating component. It is preferable that a window is formed at a portion where the heat radiating portion of the heat generating component is joined inside the heat radiating plate.

According to the power supply control device of the present invention, there is provided a wiring board having a heat conduction pattern for radiating, collecting, and equalizing heat generated from a heat-generating component on at least one layer; A metal case that contacts the conductive pattern and releases heat from the heat conductive pattern.

According to the present invention, the heat generated from the heat-generating component is transferred from the heat conductive pattern formed on the wiring board to the metal housing. The metal housing acts as a radiator, has a large heat capacity, can suppress a rapid rise in temperature, and can radiate heat while efficiently diffusing continuous heat.

According to another power supply control device of the present invention, there is provided a wiring board having a heat conductive pattern formed on at least one layer for dissipating heat generated from a heat-generating component or not conducting current for heat collection and soaking; A metal housing that contacts the heat conduction pattern formed on the plate and radiates heat of the heat conduction pattern.

The heat conduction pattern formed on the wiring board is
It is preferable that the region is divided into a plurality of regions such as a weak current region and a large current region.

Preferably, the heat conduction pattern is formed on the same layer as the circuit connection pattern.

It is preferable that the metal housing and the vehicle body are connected by a connecting member having a heat pipe.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. First of the present invention
The present embodiment relates to a heat dissipation structure of a circuit board. The heat dissipation structure of the present circuit board is characterized by the structure of the multilayer board 10. The multilayer board 10 is provided with a circuit pattern on both sides or one side of a heat dissipation plate 11 made of a metal having good thermal conductivity such as aluminum or copper. (Not shown) are laminated.

The printed circuit board 12 is slightly smaller than the heat radiating plate 11 as shown in FIG.
a is exposed, and the IPS
The heat radiating portion 8a of the heat-generating component 8 such as the
Alternatively, it is fixed with a rivet or a screw 15 with a heat transfer (insulation) sheet or silicone grease therebetween. The leads 8b of the heat generating component 8 are connected to a circuit pattern formed on the printed circuit board 12.

As shown in FIG. 2, such a multilayer board 10 is closed by a downwardly facing metal upper case 13 and an upwardly facing metal lower case 14. The periphery of the upper case 13 and the periphery of the lower case 14 are fixed to the periphery 11 a of the radiator plate 11 with screws 15 or the like. However, the upper case 13 is formed with a notch 13a so as not to be joined to the heat radiating portion 8a of the heat generating component 8 fixed to the periphery 11a of the heat radiating plate 11. Since the upper case 13 and the heat radiating portion 8a of the heat generating component 8 are not joined in this manner, the heat generating component 8 can be prevented from being damaged due to a difference in thermal expansion coefficient between the two and influence of external vibration. Then, the heat generated by the heat generating component 8 is transferred to the upper case 13 and the lower case 14 via the heat radiating plate 11 and is radiated. The upper case 13 and the lower case 14 function as a radiator, and the heat capacity is increased.

When it is difficult to fix the heat radiating portion 8a of the heat generating component 8 to the periphery 11a of the heat radiating plate 11 due to the design of the pattern, the printed circuit board 12 is provided with a window at an arbitrary place inside as shown in FIG. The heat radiating plate 11 is exposed from the window portion 12a, and the heat radiating portion 8a of the heat generating component 8 is directly or directly sandwiched between the exposed heat radiating plate 11 and the heat transfer (insulating) sheet or silicone grease. And fixed with rivets or screws. The leads 8b of the heat-generating component 8 are attached to a circuit pattern formed on the periphery 11a of the window 12a of the printed circuit board 12. Such a multilayer substrate 1
0, the upper case 13 as shown in FIG.
And the lower case 14.

Therefore, the heat generated by the heat generating component 8 is
Heat is transferred from the heat sink 11 to the upper case 13 and the lower case 14. The upper case 13 and the lower case 14 function as a radiator and have a large heat capacity, so that a rapid rise in temperature can be suppressed to a low level, and heat can be continuously dissipated while efficiently diffusing continuous heat. .

As shown in FIG. 4, the printed circuit board 12 may have the same size as the heat radiating plate 11 and may have a large number of through holes 12b formed therearound. And a printed circuit board 12 for fixing the heat radiating portion 8a of the heat generating component 8.
A copper foil pattern 16 is adhered to the portion (1), and a through hole 17 penetrating the printed circuit board 12 is formed around the copper foil pattern 16. The heat radiating portion 8a of the heat generating component 8 is fixed on the copper foil pattern 16. Even in such a multilayer substrate 10, the upper case 1 as shown in FIG.
3 and the lower case 14 are closed. Therefore, the heat generated by the heat-generating component 8 is transferred to the copper foil pattern 16 → the through hole 17 formed around the copper foil pattern 16 →
Heatsink 11 → Through hole 12b formed around printed circuit board 12 → Upper case 13 and lower case 14
And the heat is dissipated.

Further, as shown in FIG. 5, the printed circuit board 12 may have a large number of through holes 12b formed therearound and a window 12a for exposing the heat radiating plate 11 therein. The heat radiating portion 8a of the heat generating component 8 is fixed to the heat radiating plate 11 exposed by the window 12a. Even such a multilayer substrate 10 is closed by the upper case 13 and the lower case 14 as shown in FIG. Therefore, the heat generated by the heat generating component 8 passes through the through holes 12 b formed around the printed circuit board 12 from the heat radiating plate 11, and is transferred to the upper case 13 and the lower case 14 to be radiated.

It should be noted that a current may or may not flow through the radiator plate 11 as needed.

Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment of the present invention relates to a power supply control device 20. The power supply control device 20 mounts a heat-generating component 8 such as a current switching element such as a relay or a semiconductor device, and accommodates a wiring board 21 to which a connector 9 is connected in a metal housing 22,
The opening 22 a of the metal housing 22 is sealed by the lid 23. As shown in FIG. 7, the wiring board 21 is formed by forming a heat conductive pattern 21b on the back surface of the insulating layer 21a, and the back surfaces of the heat conductive patterns 21b are joined to each other.

As the insulating layer 21a, instead of the epoxy resin impregnated glass base material (prepreg) used in the ordinary laminate, an inorganic filler (silica, alumina, carbon, etc.) is used. Increase thermal conductivity. The outer periphery of the heat conductive pattern 21b is the insulating layer 21a.
And comes into contact with the metal housing 22 as shown in FIG. The metal housing 22 functions as a radiator, and the heat capacity as a whole increases.

On the surface of the insulating layer 21a, a circuit pattern for wiring a weak current circuit (hereinafter referred to as a "weak current pattern") is provided.
24) and a circuit pattern (hereinafter, referred to as a “large current pattern”) 25 for wiring a large current circuit are wired. The weak current pattern 24 is made of copper foil and has a thickness of 35 μm.
Is made of copper foil and has a thickness of 200 μm. Therefore, the insulating layer 21a between the weak current pattern 24 and the heat conductive pattern 21b is thick, and the insulating layer 21a between the large current pattern 25 and the heat conductive pattern 21b is thin. The heat conduction pattern 21b is made of copper foil and has a thickness of 300 μm.

The heat generated by the large current pattern 25 passes through the thin insulating layer 21a and is transferred from the heat conduction pattern 21b to the metal housing 22. The metal housing 22 functions as a radiator, and the heat capacity as a whole increases. Therefore,
The temperature rise can be suppressed to a low level even at the time of rapid heat generation, and the heat dissipation can be continued while efficiently diffusing even continuous heat generation. In addition, since the insulating layer 21a between the weak current pattern 24 and the heat conduction pattern 21b is thick, it is generated in the large current pattern 25 and the heat conduction pattern 21
The heat transferred to b does not reach the weak current pattern 24.

Generally, the width of a circuit pattern through which a large current flows is defined by the temperature rise when a predetermined current flows, so that the wiring board 21 having such a configuration is used so that sufficient heat radiation can be obtained. By providing a simple structure, the width of the circuit pattern, that is, the area of the wiring board 21 can be significantly reduced.

However, as shown in FIG. 9, a thin insulating layer 21a between the large current pattern 25 and the heat conductive pattern 21b.
Instead of, by interposing the high thermal conductive insulator 26,
The heat dissipation of the large current pattern 25 can be improved, and the heat transfer to the weak current pattern 24 can be completely cut off.

Further, in the wiring board 21 of the present invention, since the heat conductive pattern 21b uses the base material with copper foil used in the normal laminated wiring board 21, the pattern formation of the normal laminated wiring board 21 can be performed. Similarly, an arbitrary circuit pattern can be formed by etching. This allows
Partial separation within the wiring board 21 becomes possible.

Further, as shown in FIG. 10 (a), the wiring board 21 may have a weak current circuit region A on the center side and a large current circuit region B on the periphery. At this time, as shown in FIG. 10 (b), the heat conduction pattern 21b is divided into a weak current region X and a large current region Y at intervals corresponding to the respective regions. By doing so, it is possible to prevent the temperature of the weak current circuit region A from rapidly increasing due to the heat generated in the large current circuit region B. Therefore, the circuit operation does not become unstable, and the weak current portion is formed by one heat conduction pattern 2.
Since it is adjacent to 1b, the temperature in that region is maintained uniformly, so that a more stable circuit operation is possible.

As shown in FIG. 11, a heat conduction pattern 21b is formed in a large current region Y on the outer periphery, and a weak current region X, which does not require heat radiation,
Instead of forming b, the circuit connection pattern 27 can also be formed. As a result, in the large current region Y, the pattern width is reduced due to the heat radiation effect, and the wiring region is reduced. In the weak current region X, the high-density mounting wiring is enabled by increasing the total number of wirings.

In any case, when the power supply control device 20 is mounted on an automobile, as shown in FIG. 12, the metal housing 22 and the vehicle body 30 of the power supply control device 20 are connected to a metal bracket having good heat conductivity. The connection by 31 allows efficient heat dissipation. Since the heat of the power supply device is transmitted to the vehicle body 30 via the bracket 31 and is radiated, the heat capacity and the heat radiation capability of the power supply control device 20 are substantially increased. Conventionally, in order to secure the heat radiation capability, the surface area is increased by a radiation fin or the like, or a forced air cooling device is added by an electric fan or the like, so that a problem that the volume occupied by the device increases.

However, as described above, the power control device 20
Is transmitted to the vehicle body 30 via the bracket 31, the heat dissipation ability can be improved without increasing the volume. At this time, by combining the bracket 31 with a heat transfer member such as a heat pipe 32, the heat radiation capability can be further enhanced.

It should be noted that a current may or may not flow through the heat conducting pattern 21b as required.

The present invention is not limited to the above embodiment, and various changes can be made within the technical scope described in the claims.

[0041]

According to the heat dissipation structure for a circuit board of the present invention,
Since the heat-generating component is joined to the heat radiating plate joined to the printed circuit board, the heat generated by the heat-generating component is reliably radiated. Since the heat radiating plate is thin, the heat radiating structure can be downsized. In addition, since the heat-generating component can be joined to an arbitrary portion on the heat sink, the board can be designed without any restrictions.

According to the power supply control device of the present invention, since the heat generated from the heat-generating components is transferred to the metal housing from the heat conduction pattern formed on the wiring board, the heat capacity as a whole increases, and the temperature rises sharply. Can be kept low, and heat dissipation can be continued while efficiently diffusing even continuous heat generation. Moreover, this power supply control device
Since a special forced air cooling device is not provided, the size can be reduced, and even if the device is mounted on an automobile, it does not hinder the improvement of comfort.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a first multilayer board constituting a heat dissipation structure of a circuit board according to the present invention.

FIG. 2 is a sectional view of a main part of a heat dissipation structure of a circuit board according to the present invention.

FIG. 3 is a schematic perspective view of a second multilayer board constituting a heat dissipation structure of a circuit board according to the present invention.

FIG. 4 is a schematic perspective view of a third multilayer board constituting a heat dissipation structure of a circuit board according to the present invention.

FIG. 5 is a schematic perspective view of a fourth multilayer board constituting a heat dissipation structure of a circuit board according to the present invention.

FIG. 6 is an exploded perspective view of the power supply control device according to the present invention.

FIG. 7 is a longitudinal sectional view of a first wiring board constituting the power supply control device according to the present invention.

FIG. 8 is a partially sectional perspective view of a power supply control device according to the present invention.

FIG. 9 is a longitudinal sectional view of a second wiring board constituting the power supply control device according to the present invention.

FIG. 10 is an exploded plan view of a third wiring board included in the power supply control device according to the present invention.

FIG. 11 is a plan view of a fourth wiring board included in the power supply control device according to the present invention.

FIG. 12 is a perspective view showing a state where the power supply control device according to the present invention is mounted on a vehicle body.

FIG. 13 is an exploded perspective view of a conventional power supply control device.

[Explanation of symbols]

 8: Heating component 10: Multi-layer board 11: Heat sink 11a: Peripheral 12: Printed board 12a: Window 20: Power supply control device 21: Wiring board 21a: Insulating layer 21b: Heat conduction pattern 22: Housing 30: Body 31: Bracket 32: Heat pipe X: Low current area Y: High current area

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroyuki Yamazaki 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (7)

[Claims] A printed circuit board provided with a circuit pattern connected to a lead portion of a heat-generating component, and a heat-radiating portion of the heat-generating component directly or directly connected to a portion bonded to the printed board and not bonded to the printed circuit board. A heat dissipating structure for a circuit board, comprising: a heat dissipating plate joined by interposing a heat transfer sheet or silicon grease. 2. The heat radiating portion of the heat generating component is joined around and / or inside the heat radiating plate, and the printed circuit board has a slightly smaller size for exposing the periphery of the heat radiating plate joined to the heat radiating plate of the heat generating component. The heat dissipation structure for a circuit board according to claim 1, wherein a window is formed at a portion where the heat dissipation part of the heat generating component is joined inside the heat sink. 3. A wiring board having a heat conduction pattern formed on at least one layer for radiating, collecting, or equalizing heat generated from a heat-generating component, and contacting the heat conduction pattern formed on the wiring board. And a metal housing for dissipating heat of the heat conduction pattern. 4. A wiring board having at least one layer formed with a heat conduction pattern for dissipating heat generated from a heat-generating component or not conducting current for heat collection and soaking, and a heat conduction pattern formed on the wiring board. A power supply control device, comprising: a metal housing that contacts a pattern and radiates heat of the heat conduction pattern. 5. The power supply control device according to claim 3, wherein the heat conduction pattern formed on the wiring board is divided into a plurality of regions such as a weak current region and a large current region. . 6. The power supply control device according to claim 3, wherein the heat conduction pattern is formed on the same layer as a circuit connection pattern. 7. The power supply control device according to claim 3, wherein the metal housing and the vehicle body are connected by a connection member having a heat pipe.