JP2003258465A - Electronic circuit unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic circuit unit which is able to suppress heat of high-powered parts from being transferred to control circuit elements, such as a microcomputer, while being able to efficiently emit the heat of the high- powered parts outside, in a construction having a casing in which the high- powered part, a control circuit including the microcomputer, and the like are accommodated. <P>SOLUTION: The electronic circuit unit is characterized by forming a mounting area 12a for the high-powered part so as to have a thickness lager than that of a mounting area 12b for the microcomputer. Accordingly, the thermal density of the area 12a can be made lower than that of the area 12b, whereby the thermal resistance of the area 12a can be made relatively small. As a result, the heat generated from the high-powered part 15 is not transferred to the area 12b where the thermal resistance has become relatively large, but emitted outside from the casing 12 which is positioned in the direction opposite to the direction in which the area 12b is positioned relative to the area 12a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit unit configured by housing electronic components such as a large power consumption component with large power consumption and a control circuit including a microcomputer in a housing.

[0002]

2. Description of the Related Art For example, an electronic circuit unit such as an ECU mounted on an automobile has a circuit board on which electronic components are mounted.
It is configured to be housed in a protective case.

In this case, some electronic components mounted on the circuit board have large power consumption (large heat generation) such as a power transistor, and the heat generation itself or other electronic components relatively weak to heat ( A heat dissipation structure that does not adversely affect the microcomputer) is required.

FIG. 5 illustrates a typical heat dissipation structure of a conventional electronic circuit unit.

As shown in FIG. 5, the casing 1 is made of a material having a good thermal conductivity such as aluminum, and is formed in a rectangular box shape so that the lower surface opening is closed by the lid 2. Has become.

On the lower surface of the upper wall of the housing 1, a board 3 (ceramic board with high thermal conductivity) on which a large power consumption component 5 is mounted and a printed wiring board on which a microcomputer 6 and the like are mounted are controlled. The circuit board 4 is attached by bonding the entire back surface side.

On the upper surface of the housing 1, aluminum heat radiation fins 7 are provided.

With such a structure, the heat generated from the high-power component 5 is conducted to the housing 1 via the substrate 3 and further to the radiation fins 7 to be radiated to the outside.

[0009]

However, in the above-mentioned conventional configuration, the heat from the high-power component 5 is conducted to the entire casing 1, so that the heat is easily conducted to the control circuit board 4 and further to the microcomputer 6. There is a problem that the microcomputer 6 becomes high temperature.

Therefore, although the heat of the high-power component 5 can be efficiently radiated to the outside, it is difficult to transfer the heat to the control circuit elements such as the microcomputer 6 existing in the same housing 1. The development of a heat dissipation structure is desired.

Therefore, as an example of such a heat dissipation structure, for example, in Japanese Patent Application Laid-Open No. 9-8483, a heat-generating electronic component attached to a heat dissipation member having a heat dissipation fin is provided by a support plate having a shielding surface. It is disclosed that the covering prevents heat conduction to other components due to convection (and heat radiation) of air inside the housing.

However, in this case, although the heat conduction inside the housing can be prevented to some extent, the influence of the heat transmitted through the housing itself is overwhelmingly large, and the support plate (shielding surface) itself has a high temperature. Then, there was a risk of heat radiation from it, and so much effect could not be expected.

Therefore, in view of the above problems, an object of the present invention is to efficiently heat the large power components in an electronic circuit unit which is constructed by housing a large power component with large power consumption and a control circuit in a housing. Another object of the present invention is to provide an electronic circuit unit that can dissipate the heat to the control circuit while being able to dissipate the heat to the outside.

[0014]

An electronic circuit unit according to a first aspect of the present invention is an electronic circuit unit which is constructed by housing a large power component with large power consumption and a control circuit in the housing. In the above, by processing so that the thermal resistance of the area where the high power component is mounted is smaller than the thermal resistance of the area excluding the area, the heat of the high power component is suppressed from being conducted to the control circuit. It is characterized in that the conduction suppressing means is formed.

According to the first aspect of the present invention, the housing is provided with the heat conduction suppressing means for suppressing the heat of the high power component from being conducted to the control circuit. The heat is not conducted to the housing on the control circuit side, and is radiated to the outside from the housing located in the direction opposite to the direction in which the control circuit is located with respect to the high-power component.

As a result, the heat generated from the high-power component can be efficiently dissipated to the outside, but the conduction to the control circuit can be suppressed, so that the control circuit is adversely affected by the heat. Can be effectively prevented, and reliability can be improved.

The electronic circuit unit according to a second aspect of the present invention is characterized in that, as the heat conduction suppressing means, a region in which a high power component is mounted is formed thicker in a housing than a region in which a control circuit is mounted. . The area in which the control circuit is mounted in the housing is the control circuit mounting area, and the area in which the high power component is mounted is the high power component mounting area.

According to the second aspect of the invention, since the large power component mounting area is formed thicker than the control circuit mounting area, the heat generating density of the large power component mounting area is larger than that of the control circuit mounting area. Can be lowered, which
The thermal resistance of the high power component mounting area can be made relatively small.

As described above, when the thermal resistance of the high-power component mounting area becomes small, the heat generated from the high-power component has a characteristic of conducting heat only from the higher thermal resistance to the lower thermal resistance. , The heat is not conducted to the control circuit mounting area side where the thermal resistance becomes relatively large, and is dissipated to the outside from the case located in the direction opposite to the direction in which the control circuit mounting area is located with respect to the high power component mounting area. To be done.

As a result, the heat generated from the high-power component can be efficiently radiated to the outside, but the heat conduction to the control circuit can be suppressed. The occurrence of adverse effects can be effectively prevented, and the reliability can be improved.

In the electronic circuit unit according to a third aspect of the present invention, as the heat conduction suppressing means, in the housing, a region where the control circuit is mounted and a region where the high power component is mounted, rather than a region where the high power component is mounted. It is characterized in that the region between and is thinly formed. The area between the control circuit mounting area and the high power component mounting area is an intermediate area.

According to the third aspect of the present invention, since the intermediate region is formed thinner than the high power component mounting region, the heat generation density of the intermediate region is made higher than that of the high power component mounting region. Therefore, the thermal resistance of the intermediate region can be relatively increased.

As described above, when the thermal resistance in the intermediate region becomes large, the thermal resistance in the high power component mounting region becomes relatively small, and heat is conducted only from the higher thermal resistance to the lower thermal resistance. Therefore, the heat generated from high power components is
The heat is not conducted to the side of the intermediate region having a large thermal resistance, but is radiated to the outside from the housing positioned in the direction opposite to the direction in which the intermediate region is positioned with respect to the high power component mounting region.

As a result, the heat generated from the high-power component can be efficiently radiated to the outside, but the heat conduction to the control circuit can be suppressed. The occurrence of adverse effects can be effectively prevented, and the reliability can be improved.

Further, by combining with the features as described in claim 2, the thermal resistance of the high power component mounting area can be made smaller than the thermal resistance of the control circuit mounting area and the intermediate area, so that the large power consumption can be increased. The heat generated from the components can be further suppressed from being conducted to the control circuit.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 schematically shows a configuration of an electronic circuit unit according to an embodiment.

The electronic circuit unit 11 is constructed by housing a first substrate 13 and a second substrate 14 inside a casing 12 described later.

These first substrate 13 and second substrate 14
Is made of, for example, a ceramic substrate having good thermal conductivity, and a large power component 15 such as a power transistor having large power consumption is mounted on the surface (lower surface in the figure) of the first substrate 13. Surface of substrate 14 (bottom surface in the figure)
A control circuit is configured by mounting a microcomputer 16 and the like.

Then, the first substrate 13 and the second substrate 1
4, the entire back surface (upper surface side in the figure) is adhered to the inner surface (lower surface) of the upper wall of the casing 12,
Installed in thermal connection.

At this time, on the outer surface side of the upper wall portion of the housing 12, a first heat radiation fin 21 made of, for example, aluminum is provided corresponding to the mounting portions of the first substrate 13 and the second substrate 14, respectively. The second radiating fin 22 is attached.

The housing 12 is made of a material having good thermal conductivity such as aluminum, and has a rectangular box shape. The lower opening is closed by the lid 19 so that the housing 12 has a rectangular box shape as a whole. Has been done. The lid 19
Is attached to the lower end of the housing 12 by, for example, a plurality of screws 23, and closes the lower surface side of the housing 12.

Although not shown, for example, a flexible substrate or a flat wire may be provided between the first substrate 13 and the second substrate 14 and between them and a connector (not shown) for external connection. It is electrically connected by a well-known connection technique such as wire bonding or through-hole soldering of connector pins.

In the electronic circuit unit 11 configured as described above, the heat generated from the high-power component 15 that generates a large amount of heat is conducted from the first substrate 13 to the housing 12 and then the first radiation fin 21. Then, the heat is radiated from the housing 12 and the first heat radiation fin 21 into the outside air.

However, since the heat generated from the high-power component 15 is conducted to the entire casing 12, the heat is easily conducted to the control circuit board 14 and further to the microcomputer 16, so that the microcomputer 16 has a high temperature. is there.

Therefore, the heat of the high-power component 15 can be efficiently radiated to the outside, but it is difficult to transfer the heat to the control circuit elements such as the microcomputer 16 existing in the same housing 12. A heat dissipation structure is required.

Therefore, in the present embodiment, the housing 12 is mounted with the high power component mounting area 12a, the microcomputer 16 and the second board 14 in the area where the high power component 15 and the first board 13 are mounted. It is characterized in that the high-power component mounting area 12a is formed to be thicker than the microcomputer mounting area 12b by configuring the microcomputer mounting area 12b of the area.

As a result, the heat generation density of the high power component mounting area 12a can be made lower than that of the microcomputer mounting area 12b.
The thermal resistance of the can be relatively reduced.

When the thermal resistance of the high power component mounting area 12a becomes small, the heat has the property of being conducted only from the higher thermal resistance to the lower thermal resistance.
Is not conducted to the side of the microcomputer mounting area 12b having a relatively large thermal resistance, and is located in a direction opposite to the direction in which the microcomputer mounting area 12b is located with respect to the high power component mounting area 12a. Heat is radiated from the housing 12 to the outside.

As described above, according to this embodiment, the housing 1
2 has a configuration in which a control circuit including a high power component 15 and a microcomputer 16 is housed in 2, and the heat generated from the high power component 5 is conducted to the entire housing 1 as described in the conventional example. Unlike the one that may adversely affect the microcomputer 6, the heat generated from the high power component 15 can be efficiently radiated to the outside, but the heat conduction to the microcomputer 16 is suppressed. can do.

As a result, the adverse effect of heat on the microcomputer 16 can be effectively prevented, and the reliability can be improved.

Further, in this embodiment, the high power component mounting area 12a and the microcomputer mounting area 12b are provided so as to correspond to each other.
Since the heat radiation fins 21 and the heat radiation fins 22 are independently provided, it is possible to prevent the heat generated from the high-power component 15 from being conducted to the entire heat radiation fins and adversely affecting the microcomputer 16.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
1 schematically shows a configuration of an electronic circuit unit according to an embodiment. Since the configuration of the electronic circuit unit of this embodiment is substantially the same as that of the first embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and only different portions will be described.

In the first embodiment described above, the large power component mounting area 12a is formed thicker than the microcomputer mounting area 12b. However, in this embodiment, as shown in FIG. 2, the microcomputer mounting area 12b and the large power component mounting area 12a are formed. The region 12a is formed to have the same thickness, and the intermediate region 12c between the microcomputer mounting region 12b and the high power component mounting region 12a is formed thinner than the high power component mounting region 12a.

In the present embodiment, the notch is formed in the intermediate region 12c to realize a structure in which the intermediate region 12c is formed thinner than the high power component mounting region 12a.

As a result, the high power component mounting area 12a is formed.
Since the heat generation density of the intermediate region 12c can be made larger than the heat generation density of, the thermal resistance of the intermediate region 12c can be made relatively large.

When the thermal resistance of the intermediate region 12c becomes large, the thermal resistance of the high power component mounting region 12a becomes relatively small, and heat is conducted only from the higher thermal resistance to the lower thermal resistance. Therefore, the heat generated from the high-power component 15 is generated in the intermediate region 1 where the thermal resistance is relatively large.
The heat is not conducted to the 2c side, but is radiated to the outside from the housing 12 located in the direction opposite to the direction in which the intermediate region 12c is located with respect to the high power component mounting area 12a.

As described above, according to this embodiment, the housing 1
2 has a configuration in which a control circuit including a high power component 15 and a microcomputer 16 is housed in 2, and the heat generated from the high power component 5 is conducted to the entire housing 1 as described in the conventional example. Unlike the one that may adversely affect the microcomputer 6, the heat generated from the high power component 15 can be efficiently radiated to the outside, but the heat conduction to the microcomputer 16 is suppressed. can do.

As a result, the adverse effect of heat on the microcomputer 16 can be effectively prevented, and the reliability can be improved.

(Other Embodiments) The first embodiment and the second embodiment may be combined.

That is, as shown in FIG. 3, the high power component mounting area 12a is formed thicker than the microcomputer mounting area 12b, and the intermediate area between the microcomputer mounting area 12b and the high power component mounting area 12a is formed. 12c may be formed thinner than the high-power component mounting area 12a.

As a result, the power circuit component mounting area 1 having a higher power than the thermal resistances of the control circuit mounting area 12b and the intermediate area 12c is provided.
Since the thermal resistance of 2a can be reduced, it is possible to further suppress the heat generated from the high power component 15 from being conducted to the microcomputer.

The present invention is not limited to the above embodiments, but can be applied to various aspects.

For example, in each of the above embodiments, each substrate 1
Although ceramic substrates are used as 3 and 14, the present invention is not limited to this, and a printed circuit board using a synthetic resin as a base material may be used as the substrate.

Further, in each of the above-described embodiments, the heat is dissipated from the housing 12 to the outside air via the heat dissipating fins 21 and 22, but the invention is not limited to this, and the electronic circuit unit may be different. The structure may be provided in thermal contact with the structure to radiate heat to the structure. Alternatively, the structure may be a water-cooled type, or a structure in which heat is forcibly radiated by cooling air from a fan device.

In the second embodiment, the intermediate area 1
By forming a notch in 2c, the intermediate region 12c
However, the structure is not limited to this, and as shown in FIG. 4, for example, by providing a step in the intermediate region 12c, the intermediate region 12c can be made larger. You may implement | achieve the structure formed thinner than the power component mounting area 12a.

If the housing 12 alone can provide sufficient heat dissipation, the heat dissipation fins 21 and 22 may be omitted.

In addition, various modifications of the material and shape of the casing and the heat insulating material are conceivable, and the present invention can be appropriately modified and implemented without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a diagram showing an electronic circuit unit according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an electronic circuit unit according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an electronic circuit unit according to another embodiment of the present invention.

FIG. 4 is a diagram showing an electronic circuit unit according to another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional electronic circuit unit.

[Explanation of symbols]

11 ... Electronic circuit unit, 12 ... case, 12a ... Large electronic component mounting area, 12b ... Microcomputer mounting area, 12c ... intermediate region, 13 ... the first substrate, 14 ... second substrate, 15 ... High power components, 16 ... Microcomputer, 19 ... Lid, 21 ... First heat radiation fin, 22 ... a second radiation fin, 23 ... screw.

Claims (3)

[Claims] 1. An electronic circuit unit configured by housing a large power consumption component and a control circuit having large power consumption in a housing, wherein thermal resistance of a region in which the large power consumption component is mounted is An electronic device characterized by forming heat conduction suppressing means for suppressing heat of the high-power component from being conducted to the control circuit by performing processing so as to be smaller than thermal resistance of a region excluding the region. Circuit unit. 2. The heat conduction suppressing means according to claim 1, wherein a region in which the high power component is mounted is formed thicker than a region in which the control circuit is mounted in the casing. Electronic circuit unit. 3. As the heat conduction suppressing means, between the region in which the control circuit is mounted and the region in which the high power component is mounted, in the housing, as compared with the region in which the high power component is mounted. The electronic circuit unit according to claim 1 or 2, wherein the region is formed thin.