JPH10242675A - Heat dissipation structure in electronic devices - Google Patents

Abstract

(57) [Problem] To provide a heat dissipation structure in an electronic device having excellent heat dissipation. A glass epoxy printed board (3) is housed in a resin case (1), and components are mounted on the printed board (3). A connector 4 is fixed to the printed circuit board 3, and the connector 4 is disposed in the case opening 1a. A metal plate 7 is fixed to the printed board 3, and the metal plate 7 includes a first plate portion 8, a second plate portion 9, and a third plate portion 10. Third plate part 1
A plurality of power transistors 13 are fixed to the back surface of the “0”, and the first plate portion 8 having a rectangular frame shape is located in the case opening 1a. In this case opening 1a, the first plate portion 8 of the metal plate 7 is exposed to the outside air, and the heat generated by the power transistor 13 is released therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation structure in an electronic device.

[0002]

2. Description of the Related Art In a vehicle ECU (electronic control unit), circuit components are housed in a case. The circuit components include a power supply regulating transistor and an injector driving transistor, and the power transistor generates heat. The technology to dissipate the heat generated by this transistor to the outside of the case is disclosed in Japanese Unexamined Patent Publication No.
No. 505702. This technique will be described in detail. As shown in FIG. 14, a metal case 50 has an opening 50a, and a printed board 51 and a connector 52 are housed in the case 50. A heat radiating plate 53 is disposed on the printed board 51 at a position near the opening 50a, and a heat radiating plate 54 extends from the heat radiating plate 53 in a depth direction. Power transistors 55a, 55b and 55c are fixed to the heat dissipation plate 54, as shown in FIG.
The heat generated by the power transistors 55a, 55b, and 55c is transferred to the heat dissipation plate 5 through the heat dissipation plate 54.
3 from the heat dissipation plate 53 to the case 5
Heat is dissipated through the metal cap 56 for closing the opening 50 or the opening 50a.

[0003]

However, the case 50
When the cap 56 is made of a resin, the resin has a lower thermal conductivity than a metal, so that the heat radiation is deteriorated. In particular, as shown in FIG.
A power transistor having a large heat value (transistor 5 in FIG.
5c), the temperature of the heat radiating plate 54 at the location where the transistor is installed increases, and the power transistor (see FIG. 15) disposed at a location away from the connector 52 in the direction in which the heat radiating plate 54 extends. Of the transistor 55a) is deteriorated.

An object of the present invention is to provide a heat dissipation structure in an electronic device having excellent heat dissipation.

[0005]

According to the first aspect of the present invention, when heat is generated from the power device thermally coupled to the heat radiating plate, the heat is passed through the heat radiating plate to the outside air exposed portion in the case opening. And escaped to the outside air from the outside air exposure part. Therefore, the cooling capacity is improved as compared with the case where heat is released to the outside air through the resin case.

According to the second aspect of the present invention, when a plurality of power devices are directly fixed to a radiating plate exposed to the outside air from an opening, heat can be efficiently dissipated through a radiating path for each power device. it can. That is, FIG.
In the conventional structure shown in FIG. 1, the heat radiation path is only in one direction of arrow C. In the present invention, heat can be efficiently released by the heat radiation path for each power device.

More specifically, the radiating plate is erected from a substrate disposed in the case and extends from the upper end of the erected portion to the upper surface of the case. If it extends along, it will be practically preferable. 9. A connector arrangement opening in which a connector for electrically connecting the power device to an external device is arranged from a front end of a portion of the heat dissipation plate extending along an upper surface of the case, as described in claim 8. It is more preferable to extend the portion.

Alternatively, it is preferable that the radiating plate has a vertical portion extending in parallel with a pin row of a connector for electrically connecting the power device to an external device. This is practically preferable. Furthermore, it is more preferable that a portion of the heat dissipation plate extending along the upper surface of the case be parallel to the substrate with the connector body interposed therebetween.

Further, when the heat radiating plate is arranged so as to close the opening in the connector arranging opening, the heat radiating plate functions as a cap, so that a special cap is not required.

In addition, by providing a gap between the resin case and the heat radiating plate, the heat of the heat radiating plate is hardly transmitted to the resin case, and the resin case is protected from the heat.

In particular, when an ABS resin case is used as in claim 5, thermal deformation occurs when the temperature reaches 100.degree. C., but thermal deformation is prevented by providing a gap between the case and the heat radiation plate. It is possible to do.

According to another aspect of the present invention, a surface mount device mounted on the surface of a substrate is used as the power device, and a heat radiating plate is formed on a surface other than the surface of the surface mount device mounted on the substrate. It is practically preferable to combine them.

Here, when a heat conductive sheet is arranged between the surface mount device and the heat radiating plate, a preferable heat transfer path can be formed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 1 is a perspective view of an electronic device according to the present embodiment. FIG. 2 is a plan view of the electronic device, and FIG. 3 is a longitudinal sectional view taken along line AA of FIG. FIG. 4 is an exploded perspective view of the case 1 and other components, and FIG. 5 is an exploded perspective view of components stored in the case 1.

As shown in FIGS. 2 and 3, the case 1 has a box shape and has an opening 1a at the front. This case 1
Is made of PBT resin. As shown in FIG. 4, a pair of upper and lower guide ridges 2 is provided on both sides of the inner surface of the resin case 1.
a, 2b are provided, and the glass epoxy printed board 3 is supported between the guide ridges 2a, 2b. On the printed circuit board 3, various semiconductor devices, resistors, and capacitors are arranged. Thus, the printed circuit board 3 is stored in the case 1.

As shown in FIGS. 3 and 5, a connector 4 is fixed to the upper surface at the front end of the rectangular printed circuit board 3. The connector 4 is for electrically connecting an element (circuit) in the case 1 including a power transistor 13 described later and an external device. The connector 4 includes a resin body 5 and a plurality of lead pins 6, and the body 5 is fixed to an upper surface end of the printed circuit board 3. A recess 5 a is formed in the body 5, and each lead pin 6 penetrates the body 5. One end of each lead pin 6 is located in the concave portion 5a, and the other end penetrates the printed board 3 and is electrically connected to a conductor pattern (not shown) of the printed board 3. The body 5 of the connector 4 is located at the opening 1 a of the case 1, and a part thereof projects from the case 1.

As shown in FIGS. 3 and 5, a metal plate (heat radiating plate) 7 made of aluminum comprises a first plate portion 8 in a rectangular frame shape for closing the opening 1a of the case 1, and a first plate portion 8 And a third plate portion 10 extending downward from a rear end of the second plate portion 9. The metal plate 7 is processed by pressing. Protrusions 11a and 11b extending in the horizontal direction are provided on the third plate portion 10 of the metal plate 7, and the metal plate 7 is fixed to the printed circuit board 3 by these protrusions 11a and 11b and screws 12a and 12b penetrating the printed circuit board 3. ing. Therefore, the printed circuit board 3 in which the third plate portion 10 of the metal plate 7 is disposed in the case 1
The third plate portion 10 extends in parallel along the pin row of the connector 4.

Further, the second plate 10
A plate portion 9 extends along the upper surface of the case 1, and the second plate portion 9 is parallel to the printed circuit board 3 with the connector body 5 interposed therebetween.

The first plate portion 8 in the form of a rectangular frame is arranged so as to be exposed at the case opening portion 1a, and the body 5 of the connector 4 is arranged inside the opening portion 8a with a slight gap. Have been. As described above, the first plate portion 8 extending from the tip of the second plate portion 9 of the heat radiation plate 7 is located in the connector arrangement opening 1a.

A plurality of power transistors 13 are fixed to the back surface of the third plate portion 10 with screws 14. The ends of the leads 13 a of the power transistor 13 penetrate the printed board 3 and are electrically connected to a conductor pattern (not shown) of the printed board 3. A circuit is formed by the power transistor 13 and components mounted on the printed circuit board 3.

As described above, the aluminum metal plate 7
Are arranged so that the first plate portion 8 covers the opening 1a of the case 1, and functions as a cap. Since the first plate portion 8 of the metal plate 7 is exposed to the outside air, heat generated by the power transistor 13 and the like can be directly radiated to the outside air.

As shown in FIG. 4, engagement protrusions 15a and 15b are provided on the side surface of the resin case 1 at the opening 1a. Engaging claws 16a and 16b are provided on both sides of the first plate portion 8 of the metal plate 7. Then, as shown in FIG. 2, the engagement claws 16a, 16b and the engagement protrusions 15a, 15b are engaged, and the metal plate 7 and the case 1 are connected and supported.

At the time of assembling, first, as shown in FIG. 5, the power transistor 13 is screwed to the third plate portion 10 of the metal plate 7. Then, after the reflow process is completed, the printed circuit board 3 on which the surface mount components (SMD) are mounted is brought into contact with the metal plate 7 and screwed from below.

Subsequently, the power transistor 13, the connector 4, and the metal plate 7 are soldered to the printed circuit board 3 by jet soldering. That is, the metal plate 7 is fixed to the printed board 3 by soldering the screws 12a and 12b.

Further, the printed circuit board 3 thus assembled is inserted through the opening 1a of the resin case 1. At this time, the printed circuit board 3 is fixed by the guide ridges 2a and 2b in FIG.
Is inserted while being guided.

In the electronic device configured as described above, when the power transistor 13 generates heat, the heat is transmitted to the third plate portion 10 of the metal plate 7 and further from the third plate portion 10 to the first plate portion 9 via the second plate portion 9. Plate part 8
Conveyed to. Then, at the case opening 1a, the first
Heat is released from the plate portion 8 to the outside air. That is, the heat is directly released without the interposition of the case, and the heat dissipation is excellent. Therefore, the temperature of the power transistor 13 does not exceed the operable temperature. still,
The operable temperature of a transistor is the maximum junction temperature (junction temperature) inside the transistor, and is generally 150 ° C. Further, since the first plate portion 8 of the metal plate 7 is exposed to the outside air, the temperature of the plate itself can be kept low. As a result, heat radiation to the inside of the case 1 is reduced, and the operation-guaranteed ambient temperature of the semiconductor device and the capacitor is generally said to be 105 ° C. or lower. , And operation failure can be reliably prevented.

At this time, each power transistor 1 as shown by L1 to L5 in FIG.
A heat radiation path (heat transfer path) parallel to 3 is formed,
Heat can be efficiently released by the heat dissipation paths L1 to L5 for each power transistor. That is, in the conventional structure shown in FIG.
15, it extends in the depth direction of the case 50, and has only one heat radiation path in the direction of arrow C in FIG. 15. Since this path is a narrow path limited by the plate width d, the power transistors 55a, 55b, 5
The heat radiation of 5c was not good. On the other hand, in this embodiment, the parallel heat dissipation paths L1 to L
5, heat can be efficiently released.

Therefore, in FIG.
When the temperature of c becomes high, the heat dissipation of the transistor 55a is deteriorated. However, in this embodiment, even if one transistor 13 becomes high in temperature, the other transistors 13 are not affected by the heat. Heat can be released to the outside air.

As described above, this embodiment has the following features. (A) A metal plate 7 is arranged in a case 1 and a power transistor (power device) 1
3 is fixed and thermally connected, and the first plate portion 8 of the metal plate 7 is connected to the opening 1 provided in the case 1.
a, when heat is generated from each power transistor 13 fixed to the metal plate 7, the heat is transmitted to the outside air exposed portion in the case opening 1 a through the metal plate 7, and from the outside air exposed portion to the outside air. Escaped. Therefore, the cooling capacity is improved as compared with the case where heat is released to the outside air through the resin case. (B) As shown in FIG.
3 is directly fixed to the metal plate 7 exposed to the outside air from the opening 1a, so that the heat radiation paths L1 to L1 for each transistor are provided.
Heat can be efficiently released by L5. That is,
As the structure of the metal plate 7, the third plate portion 10
The connector 4 is erected from the printed circuit board 3 in a state of extending in parallel with the pin row, and the second plate 9 from the upper end of the third plate 10 is parallel to the printed circuit board 3 with the connector body 5 interposed therebetween. In this state, when extending along the upper surface of the case 1 and the first plate portion 8 at the tip thereof is positioned in the connector arrangement opening 1a, a practically preferable heat dissipation structure is obtained. (C) Since the opening 1a is a connector arrangement opening in which the connector 4 for electrically connecting the power transistor 13 to an external device is arranged, the metal plate 7 is arranged so as to cover the opening 1a. Then, the metal plate 7 functions as a cap, and a dedicated cap can be omitted. (Second Embodiment) Next, a second embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

FIG. 6 is a longitudinal sectional view of the electronic device of the present embodiment, and FIG. 6 corresponds to FIG. 3 in the first embodiment. FIG. 7 is an exploded perspective view. FIG.
As shown in the figure, the upper case 20 and the lower case 2
1 and an upper case 20 and a lower case 21
Consists of ABS resin. ABS resin has a lower heat distortion temperature than PBT resin (100 ° C. or lower). The heat deformation temperature of the PBT resin is generally 190 to 200 ° C.

A substrate mounting ridge 21a is formed on the inner surface of the lower case 21, and as shown in FIG.
The printed board 3 is placed so as to be in contact with 1a.
An engagement protrusion 24 is formed on the lower case 21 in FIG. 7 and an engagement claw 25 is formed on the upper case 20. The printed circuit board 3 is supported by being sandwiched between the lower case 21 and the upper case 20 by the engagement of the two. That is, instead of the engagement protrusions 15a and 15b and the engagement claws 16a and 16b of FIG. 4 in the first embodiment, the engagement protrusion 24 and the engagement claw 25 of FIG. 7 are used.

As shown in FIG. 6, a metal plate (heat radiating plate) 22 is fixed to the upper surface of the printed circuit board 3 in contact therewith. The aluminum metal plate 22 is not in contact with the upper case 20, and a gap 23 is formed between the two. That is, the gaps t1 and t2 in FIG.
Are formed. Specifically, the dimensions of t1 and t2 are several meters.
m. Therefore, the heat generated by the power transistor 13 also raises the temperature of the metal plate 22. However, the gap 23 prevents the transfer of heat from the heated metal plate 22 to the lower case 20 due to conduction heat transfer. Even if an ABS resin case having a low heat-resistant temperature is used, no problem occurs due to heat.

As described above, an inexpensive ABS resin having a low heat distortion temperature as a case forming resin can be used. In other words, when the case is made of a resin having a low heat deformation temperature, if the cooling capacity is poor, the portion in contact with the heat radiating member is deformed by heat. And such a defect does not occur.

As described above, this embodiment has the following features. (A) A gap 23 is provided between the metal plate 22 and the resin cases 20 and 21 so that they are not in contact with each other. In other words, the printed circuit board 3 made of glass epoxy is fixed in the cases 20 and 21 in a state where the printed circuit board 3 is in contact with the case, and the metal plate 22 is fixed in a state where the metal plate 22 is in contact with the board 3. And a gap 23 is provided between them. Therefore, the heat of the metal plate 22 is less likely to be transmitted to the resin cases 20 and 21 and the resin case 2
0,21 is protected from heat. (B) In particular, when the ABS resin cases 20 and 21 are used, they are thermally deformed when the temperature reaches 100 ° C., but by providing a gap 23 between the cases 20 and 21 and the metal plate 22, the thermal deformation occurs. Can be prevented. (Third Embodiment) Next, a third embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

FIG. 8 is a longitudinal sectional view of the electronic device of this embodiment. FIG. 9 is an exploded perspective view. Case 1 is A
A cutout (opening) 30 is formed on the upper surface of the case 1 on the front side. A printed board 3 is arranged in the case 1, and an aluminum metal plate 31 is fixed to the printed board 3. The metal plate 31 has a first plate part 32 and a second plate part 33. The first plate portion 32 is erected from the printed circuit board 3, and the second plate portion 33 extends horizontally from the upper end of the first plate portion 32 toward the front side. A large number of power transistors 13 are fixed on the back surface of the first plate portion 32 of the metal plate 31. The opening 1a at the front of the case is closed by an ABS resin cap 34.

The second plate portion 33 of the metal plate 31 is located at the notch (opening) 30 of the case 1, and the second plate 33 is exposed to the outside air at this notch (opening) 30. I have. That is, the second plate portion 33 of the metal plate 31 is in direct contact with the outside air.

When heat is generated from each power device 13 fixed to the metal plate 31, the heat is transmitted to the second plate 33 corresponding to the cutout portion 30 through the metal plate 31, and is released to the outside air.

A gap 35 (see FIG. 8) is formed between the metal plate 31 and the ABS resin case 1, and they are not in contact with each other. Further, the metal plate 31
A gap 36 is formed between the cap 34 and the ABS resin cap 34 so that they are not in contact with each other.
The cap 34 is supported on the case 1 by the engagement claws 16a and 16b provided on the case 1 and the engagement protrusions 15a and 15b provided on the case 1. As described above, the air gaps 35 and 36 are provided between the case 1 and the cap 34 which are weak to heat and the metal plate 31 which becomes high in temperature, so that the two have a non-contact structure. Thus, an inexpensive ABS resin can be used. (Fourth Embodiment) Next, a fourth embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

In the first embodiment, the power transistor (power device) 13 has an insertion lead 13a as shown in FIG. 3, and the lead 13a is inserted into a through hole of the printed circuit board 3 and fixed. there were. In other words, an element lead insertion component (printed board insertion component; THD) has been assumed as a power device requiring heat radiation to the outside air. On the other hand, in the present embodiment, a surface mount component (SMD) is used as a power device. This is because power devices have recently been shifting from THD to SMD, and the present embodiment is applied to a heat dissipation structure of an SMD power device in a resin case.

FIG. 10 is a plan view of the electronic device according to the present embodiment, and FIG. 11 is a longitudinal sectional view taken along line BB of FIG. FIG. 12 is an exploded perspective view of the case 1 and other components, and FIG. 13 is an exploded perspective view of components stored in the case 1.

Since the basic configuration is the same as that of the first embodiment, the description will be omitted by assigning the same reference numerals, and other different portions will be described below.
As shown in FIGS. 12 and 13, an aluminum metal plate (heat radiating plate) 7 includes a rectangular frame-shaped first plate portion 8 for closing the opening 1 a of the case 1, and a first plate portion 8.
Plate portion 9 extending rearward from the third plate portion, and third plate portions 40a, 40 extending downward from both sides of the second plate portion 9.
b and inside (center) from the third plate portions 40a, 40b
Fourth plate portions 41a and 41b extending in the direction. Further, fifth plate portions 42a and 42b extend downward from both sides of the second plate portion 9, and the fifth plate portion 4
Projections 43a, 43 inward (center) from 2a, 42b
b is extended. The third plate portions 40a, 40b and the fifth
The plate portions 42a and 42b are parallel and
The fourth plate portions 41a, 41b and the projections 43a, 43b are parallel. The metal plate 7 is formed by the projections 43a and 43b and the screws 44a and 44b penetrating the printed circuit board 3.
Are fixed to the printed circuit board 3.

On the upper surface of the printed circuit board 3, SMD power transistors 45a and 45b are mounted adjacently, and SMD power transistors 45c and 45d are mounted adjacently. As shown in FIG. 11, a rectangular heat conductive sheet 46a is adhered on the SMD power transistors 45a and 45b, and a fourth plate portion 41a of the metal plate 7 is provided thereon.
6a are arranged in a state of being pressed against each other. Similarly, SMD
A rectangular heat conductive sheet 46b is adhered on the power transistors 45c and 45d, and a fourth plate portion 41b of the metal plate 7 is disposed thereon with the heat conductive sheet 46b pressed against the heat conductive sheet 46b. . Examples of the heat conductive sheets 46a and 46b include, for example, silicone rubber. As described above, the SMD power transistors 45a to 45d are connected to the heat conductive sheets 46a and 46b.
And is thermally joined to the metal plate 7 via the

At the time of assembly, as shown in FIG.
First, SMD power transistors 45a, 45b and 45c, 45d are mounted on the printed circuit board 3 in a reflow process. Thereafter, the heat conductive sheets 46a and 46b are attached to the upper surfaces of the mounted SMD power transistors 45a to 45d, that is, the upper surfaces of the resin mold bodies for the package. Then, the printed board 3 on which the elements are mounted is brought into contact with the metal plate 7 and screwed from below. By this screwing, the heat conductive sheets 46a and 46b are sandwiched and pressed between the SMD power transistors 45a to 45d and the fourth plate portions 41a and 41b of the metal plate 7.

Subsequently, the connector 4 and the metal plate 7 are soldered to the printed circuit board 3 by jet soldering. That is, the metal plate 7 is fixed to the printed circuit board 3 by soldering the screws 44a and 44b.

In the electronic device thus configured, S
When the MD power transistors 45a to 45d generate heat,
The metal plate 7 is provided via the heat conductive sheets 46a and 46b.
The heat is transmitted to the fourth plate portions 41a and 41b of the third plate portion 40a.
a, 40b → the second plate portion 9 → the first plate portion 8, heat is transmitted, and the heat is released from the first plate portion 8 to the outside air at the case opening 1a. At this time, the first
A heat radiation path similar to that of the embodiment is formed. That is,
In the metal plate 7, each of the SMD power transistors 45a to 45d as indicated by L11 to L14 in FIG.
A heat radiation path (heat transfer path) is formed parallel to the heat sink, so that heat can be efficiently released. Further, the heat generated by the SMD power transistors 45a to 45d can be efficiently transmitted to the metal plate 7 by interposing the heat conductive sheets 46a and 46b. Further, since the heat conductive sheets 46a and 46b are used in a state where they are pressed against each other, their properties can be exhibited more effectively.

As described above, this embodiment has the following features. (A) SMD power transistors (surface mount devices) 45a to 45d mounted on the surface of the printed circuit board 3 are used as power devices, and surfaces (upper surfaces) other than the mounting surface of the SMD power transistors 45a to 45d with the printed circuit board 3 are used. ), The heat generated by the SMD power transistors 45a to 45d can be efficiently released to the outside air. (B) Since the heat conductive sheets 46a and 46b are arranged between the SMD power transistors 45a to 45d and the metal plate 7, a preferable heat transfer path can be formed.

As application examples of this embodiment, the second and third
The same effect can be obtained with a similar configuration in which the THD is replaced by an SMD as a power device.

The heat conductive sheets 46a and 46b are not always required. Furthermore, the surface mount device 45a
45d and the metal plate 7 as a thermal coupling method,
A so-called non-contact arrangement in which both are arranged close to each other may be used. In short, the plate 7 is arranged from the device 45a to 45d side.
Any heat can be transferred to the side.

Further, the surface mount devices 45a to 45a
Although it is thermally coupled to the metal plate 7 on the surface (upper surface) opposite to the mounting surface of the printed circuit board 3 in 5d, it may be thermally coupled to the metal plate 7 on a surface other than this surface.

In addition to the above-described embodiments, the present invention may be implemented as follows. The metal plate as the heat radiating member may be made of copper, iron, or the like other than aluminum.

A ceramic substrate may be used instead of the printed substrate (glass epoxy substrate).

[Brief description of the drawings]

FIG. 1 is an exemplary perspective view of an electronic device according to a first embodiment;

FIG. 2 is a plan view of an electronic device.

FIG. 3 is a longitudinal sectional view taken along line AA of FIG. 2;

FIG. 4 is an exploded perspective view of a case and other parts.

FIG. 5 is an exploded perspective view of components housed in a case.

FIG. 6 is a longitudinal sectional view of an electronic device according to a second embodiment.

FIG. 7 is an exploded perspective view of the electronic device according to the second embodiment.

FIG. 8 is a longitudinal sectional view of an electronic device according to a third embodiment.

FIG. 9 is an exploded perspective view of an electronic device according to a third embodiment.

FIG. 10 is an exemplary plan view of an electronic device according to a fourth embodiment;

FIG. 11 is a longitudinal sectional view taken along line BB of FIG. 10;

FIG. 12 is an exploded perspective view of a case and other parts.

FIG. 13 is an exploded perspective view of components housed in a case.

FIG. 14 is an exploded perspective view showing a conventional electronic device.

FIG. 15 is a cross-sectional view illustrating a conventional electronic device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 1a ... Case opening, 3 ... Printed circuit board as a glass epoxy board, 4 ... Connector, 7 ... Metal plate as heat dissipation plate, 13 ... Power transistor as power device, 20 ... Upper case, 21
... lower case, 22 ... metal plate as heat dissipation plate, 23 ... gap, 30 ... opening, 31 ... metal plate as heat dissipation plate, 45a to 45d ... SMD power transistor, 46a, 46b ... heat conductive sheet.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kozo Iwata 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Akihiro Yanagisawa 1-1-1, Showa-cho, Kariya City, Aichi Prefecture Denso Corporation Inside

Claims (12)

[Claims] 1. An electronic device in which a power device is housed in a resin case, wherein a heat dissipation plate is disposed in the case, and the power device is thermally coupled to the heat dissipation plate. A heat dissipation structure in an electronic device, wherein a part of a heat dissipation plate is exposed to outside air from an opening provided in a case. 2. The heat radiating structure in an electronic device according to claim 1, wherein the plurality of power devices are directly fixed to a heat radiating plate exposed to the outside air from the opening. 3. The heat dissipation structure according to claim 1, wherein the opening is a connector arrangement opening in which a connector for electrically connecting the power device to an external device is arranged. 4. The heat dissipation structure according to claim 1, wherein a gap is provided between the heat dissipation plate and the case. 5. The heat dissipation structure according to claim 4, wherein the case is made of ABS resin. 6. In the case, a glass epoxy or ceramic substrate is fixed to the case in contact with the case, and the heat radiation plate is fixed to the substrate in contact with the case. The heat dissipation structure in an electronic device according to claim 1, wherein a gap is provided in the electronic device. 7. The heat radiation plate according to claim 1, wherein the heat radiation plate is erected from a substrate disposed in the case, and extends along an upper surface of the case from an upper end of the erected portion. A heat dissipation structure in the electronic device described in the above. 8. The heat dissipation plate extends from a tip end of a portion extending along an upper surface of the case to a connector arrangement opening in which a connector for electrically connecting the power device to an external device is arranged. The heat dissipation structure in the electronic device according to claim 7, wherein the heat dissipation is performed. 9. The electronic device according to claim 7, wherein the standing portion of the heat radiation plate extends in parallel along a pin row of a connector for electrically connecting the power device to an external device. Heat dissipation structure. 10. The heat dissipation structure according to claim 7, wherein a portion of the heat dissipation plate extending along the upper surface of the case is parallel to the substrate with the connector body interposed therebetween. 11. The power device is a surface-mounted device mounted on a surface of a substrate, and the power device is thermally coupled to a heat-dissipating plate on a surface other than the surface of the surface-mounted device mounted on the substrate. 2. A heat dissipation structure in the electronic device according to 1. 12. The heat dissipation structure in an electronic device according to claim 11, wherein a heat conductive sheet is disposed between said surface mount device and a heat dissipation plate.