JP2014057001A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device capable of restraining heat transfer to a second region while also restraining an increase in body size.SOLUTION: An electronic control device (10) includes a substrate (30) on which an electronic component (31) is mounted to form a circuit, and a casing (50) for accommodating the substrate therein. The substrate has a first region (33) having high heating density in which a first circuit (32) is formed as a circuit and a second region (35) having lower heat density than that of the first region in which a second circuit (34) is formed as a circuit. The first circuit has, as an electronic component, a plurality of first components (36) which generate heat upon current conduction. The second circuit has, as an electronic component, a second component (37) having smaller calorific power than that of the first component and a lower guaranteed temperature than that of the electronic components of the first circuit. Further, a plurality of third components (39) having higher calorific capacity than those of the first and the second components are disposed in a boundary region (38) between the first and the second regions spreading from one end to the other end of the boundary region.

Description

  The present invention relates to an electronic control device in which a board having mounted electronic components is accommodated in an internal space of a housing.

  2. Description of the Related Art Conventionally, as an electronic control device in which a substrate having a mounted electronic component is accommodated in an internal space of a housing, for example, as shown in Patent Document 1, an electronic component that generates heat when energized (hereinafter referred to as a first component). ) To take heat dissipation from.

  In Patent Document 1, grease having good thermal conductivity is interposed between the first component and the case, and heat of the first component can be radiated to the case via the grease. Further, grease is also interposed between the back surface of the first component mounting portion of the substrate and the case, so that heat of the first component can be dissipated to the case via the substrate and the grease.

Japanese Patent Laid-Open No. 2005-5671

  By the way, from the viewpoint of miniaturization and the like, efforts are being made to form a plurality of circuits on the same substrate. For example, a first circuit formed in the first region of the substrate and having a plurality of first components, and an electron formed in the second region of the substrate and having a smaller calorific value than the first component and included in the first circuit. Consider a case where a second circuit having a second component having a guaranteed temperature lower than that of the component is formed on the same substrate.

  In this case, the first circuit has a plurality of first components, and the heat generation density (heat generation amount per unit area) of the first region of the substrate is higher than the heat generation density of the second region. Therefore, even if the double-sided heat dissipation structure described in Patent Document 1 is adopted, heat is not sufficiently released to the housing, and heat is transferred to the second region. As a result, the temperature of the second region rises, and as a result, the temperature of the second component may rise and exceed the guaranteed temperature.

  On the other hand, it is also conceivable to increase the thermal resistance and reduce the amount of heat transferred to the second component by increasing the distance between the first region and the second region in the substrate. However, the physique of the substrate and thus the electronic control device increases.

  In view of the above problems, an object of the present invention is to provide an electronic control device capable of suppressing an increase in physique while suppressing heat transfer to the second region.

In order to achieve the above object, the invention described in claim 1
A substrate (30) on which a circuit is formed by mounting an electronic component (31);
A housing (50) for accommodating the substrate therein,
The substrate has a first circuit (32) formed as a circuit and a first region (33) having a high heat generation density, and a second circuit (34) formed as a circuit and has a second heat generation density lower than that of the first region. A region (35),
The first circuit has a plurality of first components (36) that generate heat when energized as an electronic component, and the second circuit has a smaller amount of heat generation than the first component as an electronic component, and the first circuit An electronic control device having a second component (37) having a guaranteed temperature lower than that of the electronic component,
As an electronic component, a plurality of third components (39) having a larger heat capacity than the first component and the second component are connected to the boundary region (38) between the first region and the second region from one end to the other end of the boundary region. It is arranged over.

  According to this, the heat of the first region can be absorbed by the third component having a large heat capacity, thereby suppressing the heat transfer to the second region. Since the third component constituting the circuit is used for heat transfer suppression, the physique can be reduced in size as compared with the structure in which the heat transfer is suppressed by separating the distance between the first region and the second region in the same circuit. it can. As mentioned above, according to this invention, the increase in a physique can be suppressed, suppressing the heat transfer to a 2nd area | region.

  In addition, a further feature of the present invention is that the third component is a tall component that is taller than other electronic components. According to this, since the surface area of the third component is large, the heat of the first region can be absorbed compared to the low-profile component.

  A further feature of the present invention is that the third component is a surface-mount type electronic component. According to this, it is easy to arrange the inner layer wiring immediately below the third component on the substrate, and it is also possible to mount the electronic component on the back surface. Therefore, the size can be further reduced.

  Further, according to a further feature of the present invention, there is provided a covering portion (57) that covers each third component so that the housing faces not only the upper surface (39a) of the third component but also at least a part of the side surface (39b). It is in having. According to this, the heat absorbed by the third component can be easily radiated to the housing. Therefore, the heat transfer from the first region to the third component to the housing is smooth, so that heat transfer to the second region can be further suppressed.

  Furthermore, a further feature of the present invention is that the shape of the covering portion is convex on the outer surface side of the housing corresponding to the third component. According to this, it becomes easy to radiate heat from the covering portion to the outside. As a result, the heat transfer from the first region to the third component to the housing becomes smoother, and thus heat transfer to the second region can be further suppressed. Further, in the housing, the heat conduction path from the covering portion to the second region side also becomes long. Also by this, the heat transfer to the second region can be suppressed.

It is a top view which shows schematic structure of the electronic controller which concerns on 1st Embodiment. It is sectional drawing which follows the II-II line of FIG. It is a top view of a board | substrate. It is an internal view top view of an upper case. In FIG. 2, it is sectional drawing to which the 3rd component periphery was expanded. For convenience, the lower case is omitted, and the upper case is simplified. FIG. 10 is a diagram showing the results of thermal fluid analysis in a reference example in which the third part is not arranged in the boundary region. It is a figure which shows the result of a thermal fluid analysis in the electronic control apparatus shown in 1st Embodiment. It is sectional drawing which shows schematic structure of 3rd component periphery among the electronic control apparatuses which concern on 2nd Embodiment. For convenience, the lower case is omitted, and the upper case is simplified. It is sectional drawing concerning a 1st modification, and respond | corresponds to FIG. It is a top view of the board | substrate which concerns on a 2nd modification, and respond | corresponds to FIG. It is a top view of the board | substrate which concerns on a 3rd modification, and respond | corresponds to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings shown below, common or related elements are given the same reference numerals. Further, among the directions along the thickness direction of the substrate along the surface of the substrate, the alignment direction of the first region and the second region is referred to as the second direction. A direction perpendicular to both the first direction and the second direction is referred to as a third direction.

(First embodiment)
In the present embodiment, an example of an electronic control device in which an engine ECU (Electric Control Unit) of a vehicle and an EDU (Electric Drive Unit) for controlling the operation of a fuel injection valve are integrated on the same substrate is shown. In addition, this electronic control device has a waterproof structure.

  As shown in FIGS. 1 and 2, the electronic control device 10 includes a substrate 30 and a housing 50 that accommodates the substrate 30.

  The substrate 30 is a so-called printed circuit board, and wiring is arranged on an electrically insulating base material such as resin or ceramic. An electronic component 31 is mounted on the substrate 30, and a circuit is formed by the wiring and the electronic component 31 described above.

  As shown in FIGS. 2 and 3, the substrate 30 includes a first region 33 in which the first circuit 32 is formed and a second region 35 in which the second circuit 34 is formed. In the present embodiment, an EDU circuit as the first circuit 32 is formed in the first region 33, and an engine ECU circuit as the second circuit 34 is formed in the second region 35. As the EDU circuit and the engine ECU circuit, conventionally well-known ones can be adopted, and detailed description thereof is omitted. Further, as shown in FIG. 3, a first region 33 and a second region 35 are provided so as to be aligned in the second direction.

  The first circuit 32 includes, as the electronic component 31, a plurality of first components 36 that generate heat when energized. In this embodiment, the EDU circuit is configured to control the operation of the fuel injection valve provided in the four cylinders, and has eight switching elements for controlling the power state to the electromagnetic solenoid of the fuel injection valve. ing. Moreover, the gate of each switching element has a control circuit etc. which outputs the injection instruction signal according to the control signal from engine ECU. In the EDU circuit, the switching element corresponds to the plurality of first components 36.

  The second circuit 34 includes, as an electronic component, a second component 37 that generates a smaller amount of heat than the first component 36 and has a guaranteed temperature lower than that of the electronic component 31 included in the first circuit 32. In the present embodiment, the engine ECU circuit has two microcomputers as the second component 37. The guaranteed temperature of these microcomputers is 115 ° C., which is lower than the guaranteed temperature of the other electronic components 31. The guaranteed temperature of the first component 36 (switching element) is 150 ° C., and the guaranteed temperature of the third component 39 described later is 125 ° C.

As described above, since the first circuit 32 includes the plurality of first components 36, the first region 33 has a heat generation density (a heat generation amount per unit area) larger than that of the second region 35. In FIG. 3, the first region 33 has a substantially rectangular shape with a length of 51 mm in the second direction and a length of 98 mm in the third direction. The total heat generation amount of the first region 33 (the total heat generation amount of the electronic component 31) is about 20W. Therefore, the heat generation density of the first region 33 is 0.004 W / mm ² . Strictly speaking, one third component 39 is 20 mm × 20 mm, and has an area obtained by subtracting 20 mm × 30 mm from a 51 mm × 98 mm rectangle. Therefore, the heat generation density of the first region 33 is 0.0045 W / mm ² . On the other hand, the second region 35 has a rectangular shape with a length of 83 mm in the second direction and a length of 98 mm in the third direction. And the total calorific value of the 2nd field 35 is about 10W. Therefore, the heat generation density of the second region 35 is 0.001 W / mm ² . Thus, the heat generation density of the first region 33 is about four times the heat generation density of the second region 35. For this reason, the temperature rise in the first region 33 and the second region 35 differs by about four times.

  A plurality of third components 39 having a larger heat capacity than the first component 36 and the second component 37 are arranged in a boundary region 38 between the first region 33 and the second region 35 in the substrate 30. The third component 39 is disposed from one end of the boundary region 38 to the other end along the boundary region 38 so as to suppress heat conduction from the first region 33 to the second region 35.

  In the present embodiment, the boundary region 38 has a DC-DC converter that boosts the voltage of the on-vehicle battery, an aluminum electrolytic capacitor for boosting that charges high-voltage power boosted by the DC-DC converter included in the EDU circuit, and a noise removing capacitor. It has an aluminum electrolytic capacitor. That is, the boundary region 38 has a power supply circuit that charges the battery power and supplies it to the actuator. The boosting aluminum electrolytic capacitor and the noise removing aluminum electrolytic capacitor are employed as the third component 39. The third component 39 is a tall component that is taller than the other electronic components 31. The third component 39 is the component having the largest heat capacity among all the electronic components 31.

  In FIG. 3, five aluminum electrolytic capacitors arranged along the third direction are for boosting, and two electrolytic capacitors arranged along the second direction are for noise removal. These seven aluminum electrolytic capacitors are mounted on the same surface side of the substrate 30, and are arranged in a line with a slight gap along the boundary region 38 as shown in FIG. In the present embodiment, the arrangement is L-shaped. In particular, the five aluminum electrolytic capacitors for boosting are continuously arranged with almost no gap in the third direction. In the third direction, the arrangement area of the aluminum electrolytic capacitors overlaps with the entire arrangement area of the first component 36, and the arrangement area of the aluminum electrolytic capacitors is longer. In the second direction, the width of the boundary region 38 is 20 mm.

  In the present embodiment, the surface mount type third component 39 is employed. For this reason, as shown in FIG. 5, the substrate 30 has the inner layer wiring 40, and the inner layer wiring 40 is also disposed immediately below the third component 39. As shown in FIG. 2, the electronic component 31 is mounted on the back surface of the third component mounting surface of the substrate 30 directly below the third component.

  In addition, as shown in FIG. 1, the board | substrate 30 is also mounted | worn with the connector 41 which electrically relays the circuit formed in this board | substrate 30, and an external device. Further, as shown in FIG. 3, the substrate 30 has a plurality of through holes 42 for fixing to the housing 50.

  The housing 50 accommodates the substrate 30 described above. In the present embodiment, as shown in FIG. 2, the casing 50 includes two cases 51 and 52 that are divided in the first direction, and the casing 50 is formed by assembling these cases 51 and 52 using screws 53. Is done. The housing 50 is formed using a metal such as aluminum or a resin such as polyphenylene sulfide (PPS). Considering heat radiation from the electronic component 31, metal is preferable. In the present embodiment, an aluminum die-cast housing 50 is employed.

  The upper case 51 is opposed to one surface of the substrate 30 on which the third component 39 is mounted. The upper case 51 includes a breathing filter 54, a heat radiating fin 56, and a covering portion 57.

  The breathing filter 54 is for ventilating the inside and the outside of the housing 50, and prevents passage of liquid such as water and allows only gas to pass. As shown in FIG. 4, a through hole 55 is formed in the upper case 51, and a breathing filter 54 is attached to the through hole 55. When the through hole 55 and the breathing filter 54 are provided in this way, even if the internal or external temperature of the housing 50 changes and the internal or external air pressure changes, the air pressure inside the housing 50 and the external air pressure Are comparable.

  The heat radiating fins 56 increase the surface area of the housing 50 to improve heat dissipation, and are formed to protrude to the outer surface side of the upper case. Each radiating fin 56 is formed to extend in the third direction as shown in FIG. 1, and the plurality of radiating fins 56 are arranged in parallel in the second direction. In the present embodiment, as shown in FIG. 2, in the second direction, between the third component 39 and the second component 37, in other words, between the covering portion 57 and the second component 37 described later, Is formed.

  As shown in FIGS. 2 and 5, the covering portion 57 is formed so as to face not only the upper surface 39 a of the third component 39 but also at least a part of the side surface 39 b. In other words, it is formed so as to cover each third component 39. In the present embodiment, the shape of the covering portion 57 is convex on the outer surface side of the housing 50 corresponding to the third component 39. In other words, the cross-sectional shape defined by the first direction and the second direction is a shape like a pot bottom. As shown in FIGS. 1 and 4, the covering portion 57 is provided in a plane L shape along the arrangement of the plurality of third components 39. That is, all the third components 39 are covered by one covering portion 57.

  In addition to the above, the upper case 51 has a flange 58 for attaching the electronic control device 10 to another member on the outer surface side thereof. Further, as shown in FIG. 4, the upper case 51 has a screw hole 59 into which a screw 53 is inserted at the peripheral portion thereof. In addition, a groove 60 in which a sealing material (not shown) is disposed is formed on the inner surface of the upper case 51 so as to partition the peripheral portion and the inside in which the substrate 30 is disposed. In the groove 60, the upper case 51 and the lower case 52 are watertight, and the housing of the housing 50 and the connector 41 is also watertight. A pedestal 61 is provided on most of the inner surface of the upper case 51 on the inner peripheral side of the groove 60 except for the breathing filter 54 and the covering portion 57 described above. The pedestal 61 is a portion where the heat dissipating gel 62 shown in FIG. 5 is disposed, and a groove is formed on the surface of the base 61 so as to suppress the movement of the heat dissipating gel 62 in the second direction and the third direction. Is formed. In addition, as the thermal radiation gel 62, what has the electrical insulation which mixed zinc oxide and silicone, for example can be employ | adopted. As shown in FIG. 4, support portions 63 for supporting the substrate 30 are provided at the four corners on the inner peripheral side of the groove 60 in the inner surface of the upper case 51. A screw hole 64 for fixing is formed.

  As shown in FIG. 2, heat radiation fins 65 are also formed in the lower case 52. Further, although not particularly shown, a pedestal is formed corresponding to the arrangement of the heat dissipation gel 62. In the present embodiment, on the back surface of the substrate 30 opposite to the third component mounting surface, a pedestal is formed corresponding to the portion immediately below the first component mounting portion and the mounting portion of the electronic component 31. That is, the heat of the first component 36 can be radiated to the upper case 51 via the heat radiating gel 62 and can be radiated to the lower case 52 via the substrate 30 and the heat radiating gel 62.

  Further, when the surface of the housing 50 is roughened by anodic oxidation or the like, the surface area of the housing 50 is increased, so that heat dissipation can be improved. Moreover, if the surface of the housing | casing 50 is blackened by black cation electrodeposition coating etc., a heat absorption-and-release characteristic can be improved.

  Next, the effect of the characteristic part of the electronic control apparatus 10 which concerns on this embodiment is demonstrated.

  In the present embodiment, the heat capacity of the boundary region 38 between the first region 33 where the first circuit 32 is formed and the second region 35 where the second circuit 34 is formed extends from one end to the other end of the boundary region 38. A plurality of third parts 39 having large sizes are arranged. In particular, in the present embodiment, as shown in FIG. 3, a plurality of first parts 36 are disposed so as to straddle the facing part between the arrangement region of the first component 36 and the second region 35, which generate a larger amount of heat than the other electronic components 31. Three parts 39 are continuously arranged. Therefore, the heat of the first region 33 having a high heat generation density due to the plurality of first components 36 is absorbed by the third component 39 as shown in FIG. 5, thereby transferring the heat to the second region 35. Can be suppressed. In addition, the white arrow in FIG. 5 has shown heat. In addition, since the third component 39 constituting the circuit is used for heat transfer suppression, the heat transfer is suppressed by separating the distance between the first region 33 and the second region 35 in the same circuit, and separately from the circuit. The physique can be reduced in size as compared with the configuration in which the heat transfer suppressing member is provided. As described above, according to the electronic control device 10 according to the present embodiment, an increase in physique can be suppressed while suppressing heat transfer to the second region 35.

  In particular, in the present embodiment, a high-profile component that is taller than the other electronic components 31 is employed as the third component 39. In other words, a component having a larger surface area than other electronic components 31 is employed. Specifically, an electrolytic capacitor is employed. According to this, since the surface area of the third component 39 is large, the heat of the first region 33 can be absorbed as compared with the low-profile component.

  In the present embodiment, a surface mount type electronic component is employed as the third component 39. This makes it easier to place the inner layer wiring 40 as shown in FIG. 5 just below the third component 39 on the substrate 30 as compared with the insertion mounting type electronic component. Moreover, since reflow mounting is possible, as shown in FIG. 2, the electronic component 31 can also be mounted on the back surface immediately below the third component 39. Therefore, the physique of the board | substrate 30 and by extension, the electronic control apparatus 10 can be further reduced in size.

  Further, in the present embodiment, in addition to the above-described device on the side of the substrate 30, the housing 50 has a covering portion 57 that covers the third component 39. The covering portion 57 is provided so as to face not only the upper surface 39a of the third component 39 but also at least a part of the side surface 39b. That is, as shown in FIG. 5, the covering portion 57 has a bottom surface 57 a located in the vicinity of the top surface 39 a of the third component 39 and a side surface 57 b located in the vicinity of the side surface 39 b and has a concave shape when viewed from the inside. ing. Therefore, as indicated by solid arrows in FIG. 5, the heat absorbed by the third component 39 is easily radiated to the housing 50, and the heat is transferred from the first region 33 → the third component 39 → the housing 50. Become smooth. Therefore, heat transfer to the second region 35 can be further suppressed.

  In particular, in the present embodiment, the shape of the covering portion 57 is convex on the outer surface side of the housing 50 corresponding to the third component 39. For this reason, the surface area of the outer surface side of the covering portion 57 is increased, and heat is easily radiated to the outside. Therefore, the heat transfer from the first region 33 to the third component 39 to the housing 50 becomes smoother, and the heat transfer to the second region 35 can be further suppressed. Further, as indicated by a broken line arrow in FIG. 5, in the housing 50, the heat conduction path from the covering portion 57 to the second region 35 side becomes longer. Also by this, heat transfer to the second region 35 can be suppressed.

  In the present embodiment, the radiation fins 56 a are provided between the covering portion 57 and the second component 37 in the second direction. Therefore, this also increases the surface area of the outer surface side of the casing 50 and facilitates heat dissipation to the outside. Therefore, the heat transfer from the first region 33 to the third component 39 to the housing 50 can be further smoothed. In addition, the heat conduction path from the covering portion 57 to the second region 35 side can be further increased.

  The electronic control device 10 configured as described above is suitable for an electronic control device in which an engine ECU circuit and an EDU circuit that controls the operation of a fuel injection valve are integrated. The EDU circuit as the first circuit 32 has a large number of switching elements as the first component 36 that generates a large amount of heat. Therefore, the heat generation density is higher in the first region 33 in which the EDU circuit is formed than in the second region 35 in which the engine ECU circuit as the second circuit 34 is formed. Further, the engine ECU circuit includes a microcomputer as the second component 37 having a low guaranteed temperature. On the other hand, in the present embodiment, a plurality of aluminum electrolytic capacitors as the third component 39 are continuously provided in the boundary region 38 between the first region 33 and the second region 35 in substantially the entire longitudinal direction of the boundary region 38. It is arranged. Therefore, although the EDU circuit is integrated with the engine ECU circuit, the aluminum electrolytic capacitor can prevent the heat of the EDU circuit from being transmitted to the engine EDU circuit, particularly the microcomputer, to deteriorate the performance. .

  In addition, when the surface mount type third component 39 is employed as in the present embodiment, the inner layer wiring 40 can be easily disposed immediately below the third component 39. Thus, also from the viewpoint of the degree of freedom of wiring, it is preferable to employ a surface mount type component as the third component 39 arranged in the boundary region 38 between the first region 33 and the second region 35.

  In addition, this inventor examined the difference of the effect of the heat transfer suppression by arrangement | positioning of the 3rd component 39 using a thermofluid analysis. The results are shown in FIGS. 6 and 7, all the conditions are the same except that the arrangement of the third component 39 is different.

  In the reference example in which the third component 39 is not disposed in the boundary region between the first region 33 and the second region 35, as shown in FIG. 6, the heat of the first region 33 is transferred to the second region 35, It can be seen that the temperature of the second region 35 increases. Specifically, a portion of 122 ° C. to 123 ° C. exists in the second region 35.

  On the other hand, in the structure shown in this embodiment, as shown in FIG. 7, it turns out that the temperature of the 2nd area | region 35 becomes low compared with the said reference example. Specifically, the temperature in the second region 35 is decreased from 2 ° C. to 3 ° C. with respect to the reference example. As described above, this is considered to be due to the effect of the third component 39. In FIG. 7, the spread of heat from the first region 33 side to the second region 35 side is suppressed as compared to FIG.

(Second Embodiment)
In the present embodiment, description of parts common to the electronic control device 10 shown in the above embodiment is omitted.

  As shown in FIG. 8, the feature of the present embodiment is that the casing 50 (upper case 51) has a protrusion 66 that protrudes toward the inner space, and is adjacent to the third part in the longitudinal direction of the boundary region 38. 39, the protrusion 66 is disposed.

  In the example illustrated in FIG. 8, a protruding portion 66 that protrudes toward the substrate 30 is provided on the bottom surface 57 a of the covering portion 57 illustrated in the first embodiment. The protrusion 66 is provided locally in the third direction. The entire side surface of the third component 39 is not covered by the covering portion 57 and the protruding portion 66. Further, the above-described heat radiating gel 62 is interposed between the protruding portion 66 and the substrate 30 so that heat can be radiated from the substrate 30 to the upper case 51 via the heat radiating gel 62.

  According to the present embodiment, even if the number of the third components 39 is small and the distance between the adjacent third components 39 is increased, the protrusion 66 is provided so that the covering portion in the vicinity of the substrate 30 and the third component 39 is provided. The protrusion 66 will be located in the vicinity of the side surface portion where 57 does not face. Therefore, it is easy to transfer heat to the upper case 51 side. Thereby, heat transfer to the second region 35 can be suppressed.

  In particular, in the present embodiment, the heat radiating gel 62 is interposed between the protrusion 66 and the substrate 30. Therefore, the heat radiating gel 62 is not interposed, and the protruding portion 66 can easily transfer heat to the upper case 51 side as compared with the configuration in which the protruding portion 66 is not in contact with the substrate 30. Thereby, the heat transfer to the second region 35 can be further suppressed.

  The protrusion 66 may be provided so as to contact the surface of the substrate 30. However, there are factors such as manufacturing variations, assembly tolerances, and warpage of the substrate 30.

  In the above embodiment, the example in which the entire side surface of the third component 39 is not covered by the covering portion 57 and the protruding portion 66 has been described. However, a configuration in which the covering portion 57 is provided for each third component 39, that is, a configuration in which the third component 39 is surrounded by the covering portion 57 may be employed. In this case, the protruding portion 66 is provided between the adjacent covering portions 57.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  An example of the electronic control unit 10 having the EDU circuit that controls the operation of the fuel injection valve as the first circuit 32 and the engine ECU circuit as the second circuit 34 is shown. However, the circuit configuration is not limited to the above example. The first circuit 32 includes a plurality of first components 36 having a large heat generation amount, so that the heat generation density of the first region 33 where the circuit 32 is formed is higher than the heat generation density of the second region 35. Can be adopted. Further, as the second circuit 34, it is possible to employ a second component 37 that is vulnerable to heat and the second region 35 where the circuit 34 is formed has a lower heat generation density than the first region 33. it can. For example, a power supply circuit can be adopted as the first circuit 32.

  The second component 37 is not limited to a microcomputer. Any device can be employed as long as it generates less heat than the first component 36 and has a guaranteed temperature lower than that of the electronic component 31 included in the first circuit 32. For example, an integrated IC can be adopted.

  The third component 39 is not limited to an aluminum electrolytic capacitor. Of the electronic components 31 constituting the circuit formed on the substrate 30, a component having a large heat capacity can be adopted. For example, a coil can be adopted. Further, the third component 39 is not limited to a tall component that is taller than the other electronic components 31. Any component having a heat capacity larger than at least the first component 36 and the second component 37 may be used.

  In addition, an example in which the shape of the covering portion 57 is convex toward the outer surface side of the housing 50 corresponding to the third component 39 is shown. However, for example, as shown in FIG. 9, the outer surface side of the covering portion 57 may be a flat shape substantially parallel to the surface of the substrate 30. Also in this case, the covering portion 57 has a bottom surface 57a positioned in the vicinity of the upper surface 39a of the third component 39 and a side surface 57b positioned in the vicinity of the side surface 39b, and has a concave shape as viewed from the inside. For this reason, heat can be efficiently radiated from the third component 39 to the housing 50.

  In addition, the example in which the third components 39 are arranged in a line along the boundary region 38 is shown. However, the arrangement of the third component 39 is not limited to the above example. What is necessary is just to arrange | position from the one end of the boundary area | region 38 to the other end so that the 1st area | region 33 and the 2nd area | region 35 may be divided | segmented. For example, as shown in FIG. 10, a part of two rows may be arranged. Further, a plurality of rows may be arranged from one end of the boundary region 38 to the other end. Furthermore, a staggered arrangement may be employed from one end of the boundary region 38 to the other end.

  In addition, an example in which a boundary region 38 is provided between the first region 33 and the second region 35 as a region different from the regions 33 and 35 has been described. As a specific example, a current supply circuit having a DC-DC converter and a step-up electrolytic capacitor as the third component 39 is not included in the EDU circuit as the first circuit 32. However, for example, if the current supply circuit is regarded as a part of the EDU circuit, the third component 39 constituting the first circuit 32 is connected to the edge of the first region 33 on the second region 35 side, as shown in FIG. It may be provided in the region, that is, the boundary region 38. Although not shown, similarly, the third component 39 constituting the second circuit 34 may be provided in the edge region on the first region 33 side in the third region 35, that is, the boundary region 38.

  An example of a surface mount type is shown as the third component 39. However, the insertion mounting type third component 39 can also be adopted. As described above, it is preferable to adopt a surface mount type.

  Although the example in which the casing 50 has the covering portion 57 has been shown, the casing 50 without the covering portion 57 can also be adopted. As described above, the housing 50 having the covering portion 57 is preferably adopted.

  Although the case 50 has shown the example which has the radiation fin 56a between the coating | coated part 57 and the 2nd component 37, it is good also as a structure without the radiation fin 56a. As described above, the housing 50 having the heat radiation fins 56a is preferably adopted.

  The example in which the third component 39 is mounted on the same surface as the mounting surface of the first component 36 and the second component 37 on the substrate 30 and the covering portion 57 is formed on the upper case 51 is shown. However, the third component 39 may be mounted on the back surface of the mounting surface of the first component 36 and the second component 37 on the substrate 30, and the covering portion 57 may be formed on the lower case 52.

DESCRIPTION OF SYMBOLS 10 ... Electronic controller, 30 ... Board | substrate, 31 ... Electronic component, 32 ... 1st circuit, 33 ... 1st area | region, 34 ... 2nd circuit, 35 ... 1st 2 region, 36 ... 1st part, 37 ... 2nd part, 38 ... boundary region, 39 ... 3rd part, 39a ... upper surface, 39b ... side surface, 39c ... Terminals, 39d ... seismic base, 40 ... inner layer, 41 ... connector, 42 ... through hole, 50 ... frame, 51 ... upper case, 52 ... lower case, 53. ..Screw, 54 ... breathing filter, 55 ... through-hole, 56, 56a ... radiating fin, 57 ... covering, 57a ... bottom, 57b ... side, 58 ... Flange, 59 ... screw hole, 60 ... groove, 61 ... pedestal, 62 ... heat dissipation gel, 63 ... support part, 64 ... ne Hole, 65 ... radiator fins, 66 ... projecting portion

Claims (9)

A substrate (30) on which a circuit is formed by mounting an electronic component (31);
A housing (50) for accommodating the substrate therein,
The substrate is formed with the first circuit (32) as the circuit, the first region (33) having a high heat generation density, and the second circuit (34) as the circuit, and the heat generation density is higher than that of the first region. A lower second region (35),
The first circuit has a plurality of first components (36) that generate heat when energized as the electronic component, and the second circuit has a heat generation amount smaller than that of the first component as the electronic component, and An electronic control unit having a second component (37) having a guaranteed temperature lower than that of the electronic component of the first circuit,
As the electronic component, a plurality of third components (39) having a larger heat capacity than the first component and the second component are included in the boundary region (38) between the first region and the second region. An electronic control device, wherein the electronic control device is arranged from one end to the other end.   The electronic control device according to claim 1, wherein the third component is a tall component that is taller than the other electronic components.   The electronic control device according to claim 1, wherein the third component is a surface-mount type electronic component.   The casing has a covering portion (57) that covers each third component so as to face not only the upper surface (39a) of the third component but also at least a part of the side surface (39b). The electronic control device according to claim 1.   The electronic control device according to claim 4, wherein the covering portion is convex on the outer surface side of the housing corresponding to the third component.   The electronic control device according to claim 4, wherein the casing includes a heat radiating fin (56 a) between the covering portion and the second component. The housing has a protruding portion (66) protruding toward the inner space side,
The electronic control device according to claim 1, wherein the projecting portion is disposed between the third parts adjacent to each other in a direction along the boundary region.   The electronic control device according to claim 1, wherein the third component is an electrolytic capacitor. The first circuit is a drive circuit that drives an actuator;
The second circuit is a control circuit that outputs a drive control signal to the drive circuit,
The first component is a switching element;
The second component is a microcomputer,
The electronic control device according to claim 8, wherein the third component is a step-up electrolytic capacitor.

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