JP2003188563A - Electronic control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively dissipate heat from a heat generating SMD (surface mount device), which is subjected to surface mounting on a printed board of an electronic control unit, to a case side formed in a bag structure. <P>SOLUTION: A heat dissipation plate 41 is closely fixed to a heat dissipation pattern 33 which is subjected to heat conduction directly from a heat absorbing pattern 32, wherewith a heat generating SMD 35 subjected to surface mounting on a printed board 31 is in contact. The heat dissipation plate 41 is brought into contact with an inner wall surface 11a of a case 11 of an ECU 10, which has a bag structure having an opening part 13 in one direction and constitutes an electronic control circuit 30 inside, and built in it. Therefore, heat from the SMD 35 can be dissipated to the case 11 side via a heat dissipation plate 41 through the heat absorbing pattern 32, a through-hole plating part 34 and the heat dissipation pattern 33. That is, heat from the SMD 35 as an electronic component with heat generation property, which is subjected to surface mounting on the printed board 31, can be dissipated effectively to the outside of the ECU 10. <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 control device using a case having a bag structure, and can be used, for example, in an electronic control device mounted in an engine room of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a prior art document related to an electronic control device, one disclosed in Japanese Patent Laid-Open No. 9-207691 is known. In this case, an electronic control unit (electronic control circuit) is housed in an inner box part of a storage box (electro box) having a double structure of an inner box part and an outer box part, There is disclosed a technique of suppressing the temperature rise of the electronic control unit by causing cooling air to flow between the and (air passage). At this time, since the cooling air does not directly hit the electronic control unit, even if the cooling air contains dust, water, or the like, it is possible to eliminate the adverse effect on the electronic control unit.

However, when the storage box has a double structure as described above, the cooling air cannot be directly applied to the electronic control unit and the cooling is indirectly performed, so that heat generation in the electronic control unit will further increase in the future. Then, with such a structure, a sufficient cooling effect cannot be obtained.

As a countermeasure against this, Japanese Patent Laid-Open No. 2000-2000
The one disclosed in Japanese Patent Laid-Open No. 101273 is known. In this product, among various electronic components assembled on the printed circuit board, the electronic component having heat generation is made of an aluminum plate material etc. which is screwed and fixed to the printed circuit board, and is screwed to the heat sink surface with good heat dissipation. The heat sink is tightly fixed and screwed to the inner wall surface of the case. As a result, it is expected that the heat generated from the electronic component having the heat generating property is conducted to the case side via the heat sink and the electronic component having the heat generating property is efficiently cooled.

[0005]

By the way, in recent years, in an electronic control circuit of an electronic control unit, an SMD that can be directly mounted on a printed circuit board surface as an electronic component having heat generation property.
(Surface Mounted Devices)
There is a tendency to shift to the form of heat radiation from the MD directly to the circuit pattern of the printed circuit board. When this SMD is used, the heat sink can be eliminated, which is advantageous in cost and high density. However, in the case using the case having the conventional bag structure, the heat generated from the SMD cannot be directly conducted from the printed circuit board side to the case side, so that there is a problem that the heat-generating SMD cannot be efficiently cooled. It is expected to occur.

Therefore, the present invention has been made in order to eliminate the predictability of such a defect, and heat generation from a heat-generating SMD surface-mounted on a printed circuit board of an electronic control unit using a case having a bag structure. It is an object to provide an electronic control device capable of radiating heat to the case side.

[0007]

According to another aspect of the present invention, there is provided a heat radiation pattern portion for heat conduction directly from a heat absorption pattern portion which is surface-mounted on a printed circuit board and is in contact with a heat-generating SMD. The heat radiating plate is closely attached and fixed, and the heat radiating plate has a bag structure having an opening in one direction, and is attached by being brought into contact with the inner wall surface of the case of the electronic control unit that constitutes the electronic control circuit inside. Therefore, the heat generated from the SMD can be radiated from the heat absorbing pattern portion and the heat radiating pattern portion on the back side thereof to the case side through the heat radiating plate, that is, from the SMD as a heat-generating electronic component surface-mounted on the printed circuit board. The heat generated by is efficiently dissipated to the outside of the electronic control unit.

In the electronic control unit of the second aspect, since the heat dissipation plate is fixed to the inner wall surface of the case, the contact resistance between the heat dissipation plate and the inner wall surface of the case is reduced, and a higher heat dissipation effect can be obtained.

In the heat dissipation plate of the electronic control device according to the third aspect of the present invention, since the heat conducting member having flexibility is interposed between the heat dissipation pattern part of the printed circuit board and the case, the heat dissipation plate and the heat dissipation pattern part are provided. The contact resistance between the space and between the heat dissipation plate and the inner wall surface of the case is reduced, and a higher heat dissipation effect is obtained.

According to another aspect of the electronic control device of the present invention, since the heat dissipation plate is closely contacted only with the heat dissipation pattern portion of the printed circuit board, other electronic parts and circuits are not contacted with the heat dissipation plate on the printed circuit board surface. Patterns can be arranged and mounting efficiency is improved.

According to another aspect of the electronic control device of the present invention, since the heat radiation plate has the heat radiation pattern portions formed on both sides of the printed circuit board, a plurality of heat radiation patterns are arranged on both sides of the printed circuit board so as to be in close contact with these heat radiation pattern portions. Installed and combined. As a result, it is possible to radiate heat to any SMD that is surface-mounted regardless of the front and back surfaces of the printed circuit board.

According to another aspect of the electronic control apparatus of the present invention, the heat dissipation plate can fix the printed circuit board whose outer dimensions in the direction perpendicular to the housing direction are reduced without changing the outer dimensions thereof. . Therefore, even in a printed circuit board whose external dimensions are reduced and changed, the heat dissipation plate absorbs the difference in size, so that the case can be standardized.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on Examples.

FIG. 1 is a cross-sectional view showing a main part configuration of a printed circuit board accommodated in a case of an electronic control unit to which an electronic control device according to an embodiment of the present invention is applied, taken along the plane of the board. 2 is a top view showing the configuration of the main part of the electronic control unit shown in FIG. 1 when the cover is removed from the case and viewed from the opening side, and FIG. 3 is a line AA and line BB in FIG.
It is sectional drawing which follows the line.

1, 2, and 3, reference numeral 10 denotes an electronic control unit (hereinafter, referred to as "EC").
U ”), the ECU 10 is arranged such that the printed circuit board 31 is inserted and accommodated in the direction along the plane of the board from the opening 13 side of the upper end surface of the case 11 having a bag structure formed of aluminum alloy die casting. There is.

An SMD which is an electronic component having a heat generating property in a predetermined circuit pattern (not shown) of the printed board 31.
An electronic control circuit 30 is configured by mounting (for example, a power transistor) 35 and various other electronic components (not shown). An external connector 39 for connecting the electronic control circuit 30 to the outside is provided on the upper end surface of the printed board 31.
Has its terminals soldered and fixed with screws.

Further, the SM mounted on the printed circuit board 31
On the printed circuit board 31 surface which is the back side of D35, SMD
The endothermic pattern portion 32 having a land shape independent of the circuit pattern for surface mounting 35 is formed,
It is in contact with the back side of the SMD 35. Further, a heat radiation pattern portion 33 having a considerable area is formed on the back surface side of the printed circuit board 31 corresponding to at least the position of the heat absorption pattern portion 32 of the printed circuit board 31, and the printed circuit board 31 is formed.
A plurality of through-hole plated portions 34 for connecting both the pattern portions 32, 33 to each other so as to conduct heat directly from the heat absorbing pattern portion 32 to the heat radiating pattern portion 33 are formed therein.

Corresponding to the heat dissipation pattern portion 33 of the printed circuit board 31 thus formed, it is extended leftward and rightward with a predetermined width and vertically extended at the portions apart from the left and right end surfaces of the printed circuit board 31 so as to be integrated. The heat dissipation plate 41 made of metal having excellent heat conductivity is attached to the printed circuit board 31 with the screws 4
It is fixed with screws at 5. In addition, the heat dissipation plate 41 of this embodiment is an S-type surface-mounted on the printed circuit board 31.
Corresponding to the three-stage arrangement of MD35, it is formed in a "Sun" shape. In this way, the heat dissipation plate 41 screwed and fixed to the printed board 31 with the screws 45 is in close contact with the respective heat dissipation pattern portions 33 formed on the back surface side of the printed board 31.

Then, a cover 21 formed of aluminum alloy die casting so as to cover the periphery of the external connector 39 is provided with a printed board 31 via a projecting portion 22 thereof.
It is fixed by screwing with a screw 25. This allows
The printed circuit board 31 on which various electronic components including the SMD 35 are mounted and the external connection connector 39 are integrated with the cover 21 to form a “circuit ASSY”. In a state where the circuit ASSY is completely accommodated in the case 11, the end surface of the printed board 31 on the insertion tip side is brought into contact with the positioning portions 15 provided at both ends of the inner bottom surface of the case 11, and the front and rear surfaces thereof are arranged in the same direction. Are clamped and fixed by a plurality of protrusions 16 provided on the inner bottom surface of the case 11.

Further, at a portion of the printed circuit board 31 of the circuit ASSY separated from both ends, the protrusion 2 from the cover 21 is provided.
3 is formed, and the projecting portion 23 is screwed and fixed from the outer surface of the case 11 with the screw 26, so that the opening 13 side of the case 11 exposes the terminal portion of the external connection connector 39 to the outside. Only with this, the cover 21 is covered. Thus, the cover 21 is screwed and fixed to the case 11 by the screws 26, so that the left and right end surfaces of the heat dissipation plate 41 are attracted toward the inner wall surface 11a of the case 11 and assembled in a contact state.

As described above, the electronic control unit of this embodiment is
Case 11 having a bag structure having an opening 13 in one direction
An ECU (electronic control unit) 10 that forms an electronic control circuit 30 inside, and an SMD 35 as an electronic component that is surface-mounted and has heat generation property in a part of a circuit pattern (not shown) that forms the electronic control circuit 30 of the ECU 10. A heat sink pattern portion 32 which is in contact with the heat sink pattern portion 32 and a heat sink pattern portion 32 which is directly heat-transmitted from the heat sink pattern portion 32 on the back side of the heat sink pattern portion 32, and a heat sink pattern portion 33 of the print substrate 31. And a heat radiating plate 41 that is attached to and fixed to the inner wall surface 11a of the case 11 of the ECU 10 for assembly.

That is, the heat radiation pattern portion 33, which is directly heat-transferred from the heat absorption pattern portion 32, which is surface-mounted on the printed circuit board 31 and is in contact with the heat-generating SMD 35,
The heat radiating plate 41 is closely attached and fixed, and the heat radiating plate 41 has a bag structure having an opening 13 in one direction and is attached by being brought into contact with the inner wall surface 11a of the case 11 of the ECU 10 which constitutes the electronic control circuit 30 inside. .

Therefore, the heat generated from the SMD 35 can be radiated from the heat absorption pattern portion 32, the through-hole plating portion 34, and the heat radiation pattern portion 33 to the case 11 side through the heat radiation plate 41, that is, surface mounted on the printed circuit board 31. It is possible to efficiently dissipate heat generated from the SMD 35, which is an electronic component having heat generation, to the outside of the ECU 10.

FIG. 4 shows, as a modified example in which the heat radiating plate 41 corresponding to FIG. 3B of the above-described embodiment is screwed and fixed to the inner wall surface 11a of the case 11, the main configuration of the ECU 10 viewed from the side. FIG.

As shown in FIG. 4, in this modified example, the heat dissipation plate 41 is screwed and fixed from the outside of the case 11 with the screw 49, so that the heat dissipation plate 41 surely contacts the inner wall surface 11a of the case 11. Will be done.

As described above, the ECU 10 as the electronic control device of this modification fixes the heat dissipation plate 41 to the inner wall surface 11a of the case 11. Therefore, the contact resistance between the heat dissipation plate 41 and the inner wall surface 11a of the case 11 is reduced, and a higher heat dissipation effect can be obtained.

FIG. 5 is a heat conduction sheet 43 having flexibility between the heat dissipation plate 41 and the heat dissipation pattern portion 33 of the printed circuit board 31 and between the heat dissipation plate 41 and the inner wall surface 11a of the case 11 in the above-described embodiment. It is a block diagram which shows the modification which each intervened. FIG. 6 is a partially enlarged view showing the structure of the main part of FIG.

As shown in FIGS. 5 and 6, the circuit A
A heat conductive sheet 42 having flexibility is interposed between the heat dissipation plate 41 forming the SSY and at least the heat dissipation pattern portion 33 formed on the printed board 31 with which the heat dissipation plate 41 is in contact. A heat conductive sheet 43 having flexibility between the inner wall surface 11a
Is intervening.

As described above, the heat dissipation plate 41 of the ECU 10 as the electronic control unit of this modification is the printed circuit board 3
1, a heat conduction sheet 42 as a heat conduction member having flexibility between the heat radiation pattern portion 33 and the case 11.
43 is interposed. Therefore, between the heat dissipation plate 41 and the heat dissipation pattern portion 33 and between the heat dissipation plate 41.
The contact resistance between the case and the inner wall surface 11a of the case 11 is reduced, and a higher heat dissipation effect can be obtained.

Next, a modified example of the heat dissipation plate 41, which is in close contact with the heat dissipation pattern portion 33 of the printed circuit board 31 in the above-described embodiment and is fixed by screws 45, will be described.
This will be described with reference to FIGS. 7 and 8. Here, FIG. 8 (a)
Is a cross-sectional view taken along the line CC of FIG. 7, and FIG.
It is sectional drawing which follows the -D line.

The heat dissipation plate 41 in the above embodiment
Are formed in a plane so that almost the entire surface is in close contact with the surface of the printed board 31. On the other hand, the heat dissipation plate 44 of the present modified example shown in FIGS. 7 and 8 is bent so as to be in close contact with only the heat dissipation pattern portion 33 formed on the back surface side of the printed circuit board 31 on which the SMD 35 is surface-mounted. ing.

As described above, in the ECU 10 as the electronic control device of this modification, the heat dissipation plate 44 is attached to the printed circuit board 3.
Only one heat radiation pattern portion 33 is closely attached. Therefore, other electronic components and circuit patterns can be arranged in the portion where the heat dissipation plate 44 is not in close contact with the surface of the printed circuit board 31, and the mounting efficiency can be improved.

Next, SMD3 is formed on both sides of the printed circuit board 31.
A modified example of the heat dissipation plate when the surface mounting member 5 is mounted will be described with reference to FIGS. 9 and 10. here,
10A is a sectional view taken along the line EE of FIG.
10B is a sectional view taken along the line FF of FIG. 9, and FIG. 10C is a sectional view taken along the line GG of FIG. 9.

As shown in FIGS. 9 and 10, the SMD 35 is surface-mounted on both surfaces of the printed circuit board 31 of the present modification, and the printed circuit board 31 has heat radiation pattern portions 33 on both surfaces corresponding to these SMDs 35. Are formed. For this reason, two heat radiation plates 46 and 47 are arranged and combined so as to be in close contact with both surfaces of the printed circuit board 31, respectively, and fixed by screws 45.

As described above, the ECU 10 as the electronic control device of the present modification is configured so that the heat radiation plate 4 is formed when the heat radiation pattern portions 33 are formed on both surfaces of the printed board 31.
A plurality of 6, 47 are arranged so as to be in close contact with the heat radiation pattern portion 33 and are combined. By using the heat dissipation plates 46 and 47 configured as described above, any SM surface-mounted on the front and back surfaces of the printed board 31 can be used.
It can also radiate heat to D35, and can also be compatible with double-sided reflow soldering.

Next, as a modification, the external dimensions of the printed circuit board 31 in the above-described embodiment shown in FIG. 11 (b) are reduced and changed, and the printed circuit board 31 shown in FIG. 11 (a). A case in which ′ is housed in the case 11 will be described.

The circuit ASSY shown in FIGS. 11A and 11B, in which the cover 21 is omitted, has different electronic control circuits 30 from each other, so that the printed circuit board 3
The number and the external dimensions of the SMDs 35 mounted on 1, 31 'are different. In the printed circuit board 31 ′ of the circuit ASSY shown in FIG. 11A, only the outer dimensions of the printed circuit board 31 are reduced and changed in the direction (right and left direction in the figure) perpendicular to the housing direction of the case 11. For this reason,
If the circuit ASSY of 1 (a) has a size of the case 11 which can accommodate the circuit ASSY of FIG. 11 (b), the circuit ASSY of FIG. Heat dissipation plate 41 shown
It is possible to accommodate the printed circuit boards 31 ′ having different outer dimensions by using the same one as described above. It should be noted that the dimensions of the external connection connector 39 'of this modification are different from the dimensions of the external connection connector 39 in the left-right direction, and the case 11 is shared, but a cover (not shown) for this case 11 cannot be shared. Becomes

As described above, the heat radiation plate 41 of the ECU 10 as the electronic control device of the present modification has a reduced outer dimension in the direction perpendicular to the housing direction without changing its outer dimension. The substrate 31 'can be fixed. Therefore, even if the printed circuit board 31 'has a reduced outer dimension, the heat dissipation plate 4
Case 1 because 1 absorbs the difference in size.
Commonality can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of a state in which a printed circuit board is accommodated in a case of an ECU to which an electronic control device according to an embodiment of the present invention is applied, taken along a plane of the circuit board. Is.

FIG. 2 is a top view showing a configuration of a main part of the ECU of FIG. 1 when a cover is removed from the case and viewed from the opening side.

3 is a cross-sectional view taken along line AA and line BB in FIG.

FIG. 4 is a cross-sectional view showing a modified example in which the heat dissipation plate corresponding to FIG. 3 is screwed and fixed to the inner wall surface of the case.

FIG. 5 is a view showing a space between a heat radiating plate of an ECU and a heat radiating pattern portion of a printed circuit board to which an electronic control device according to an embodiment of the present invention is applied, and a heat radiating plate and an inner wall surface of a case. It is a block diagram which shows the modification which interposed the heat conductive sheet which has flexibility between each.

FIG. 6 is a partially enlarged view showing the configuration of the main part of FIG.

FIG. 7 is a configuration diagram showing a modified example of a heat dissipation plate of an ECU to which an electronic control device according to an embodiment of the present invention is applied.

FIG. 8 is a cross-sectional view taken along line CC and line DD of FIG. 7.

FIG. 9 is a configuration diagram showing another modified example of the heat dissipation plate of the ECU to which the electronic control device according to one example of the embodiment of the present invention is applied.

10] FIG. 10 is a line EE, a line FF, and a line G in FIG. 9. [FIG.
It is sectional drawing which follows the -G line.

FIG. 11 is a configuration diagram showing how the ECU to which the electronic control device according to the embodiment of the present invention is applied responds to the reduction and change of the external dimensions of the printed circuit board.

[Explanation of symbols]

10 ECU (electronic control unit) 11 cases 11a (of the case) inner wall surface 13 (case) opening 30 Electronic control circuit 31 printed circuit board 32 Endothermic pattern 33 Heat dissipation pattern 35 SMD (electronic parts with heat generation) 41 Heat dissipation plate

Claims (6)

[Claims] 1. An electronic control unit forming an electronic control circuit inside a case having a bag structure having an opening in one direction, and a surface on a part of a circuit pattern forming the electronic control circuit of the electronic control unit. A printed circuit board that forms a heat absorption pattern part that is mounted and in contact with an electronic component having heat generation, and a heat dissipation pattern part that is directly heat-conducted from the heat absorption pattern part on the back surface side of the heat absorption pattern part; 2. An electronic control device, comprising: a heat radiating plate that is fixed in close contact with the heat radiating pattern portion and is attached to the inner wall surface of the case of the electronic control unit in contact therewith. 2. The electronic control device according to claim 1, wherein the heat dissipation plate is fixed to an inner wall surface of the case. 3. The heat dissipation plate has a heat conductive member having flexibility interposed between the heat dissipation plate and the heat dissipation pattern portion of the printed circuit board. The electronic control device according to. 4. The electronic control device according to claim 1, wherein the heat dissipation plate is closely attached only to the heat dissipation pattern portion of the printed circuit board. 5. The heat radiating plate, when the heat radiating pattern portions are formed on both surfaces of the printed circuit board, a plurality of the heat radiating plates are arranged so as to be in close contact with the heat radiating pattern portions, and are combined. The electronic control device according to any one of claims 1 to 4. 6. The heat dissipation plate can fix the printed circuit board in accordance with the reduction of the outer size of the printed circuit board, and the printed circuit board can be fixed. Electronic control unit.