JP6250997B2 - Electronic control unit - Google Patents

Description

  The present invention relates to an electronic control device, and more particularly to an electronic control device that can improve heat dissipation of a heat-generating component.

Various electronic control devices such as for engine control, motor control, and automatic transmission control are mounted on vehicles such as automobiles. The electronic control device includes a circuit board on which electronic components having a large amount of heat generation such as a memory, a microcomputer, and an ASIC (Application Specific Integrated Circuit) are mounted, and a housing that houses the circuit board.
Such an electronic control device needs to cool the heat generated by an electronic component having a large calorific value, and performs cooling by forced convection using a fan or the like and a method of circulating a coolant through a cooling path formed by piping. Yes.

However, there is a method of cooling the casing by natural convection or radiation for the purpose of reducing the space or weight for installing the fan or piping, or due to restrictions from surrounding structures.
As an example of such an electronic control device, there is known a structure in which a circuit board on which electronic components are mounted is accommodated in a main body provided with heat radiation fins, and the main body is covered with a lid having irregularities formed on the inner surface (for example, , See Patent Document 1). In this structure, the heat radiation area can be increased by the unevenness provided on the surface of the lid.

Japanese Patent No. 2011-199092

  In the electronic control device described in Patent Document 1, since there is a gap between the lid and the electronic component mounted on the circuit board and having a large amount of heat generation, the heat dissipation efficiency is low.

The electronic control device of the present invention includes a circuit board, a heat generating component mounted on the circuit board, a main body, and a bulge formed on one surface of the main body corresponding to the area of the circuit board on which the heat generating component is mounted. A support member that supports the circuit board, a raised portion of the support member, and a region of the circuit board on which the heat generating component is mounted, or between the raised portion of the support member and the heat generating component. The support member has a first region formed on one surface of the main body portion, each of which includes a plurality of closed-shaped rib structures, and a second region, The height of the rib structure in one region is lower than the height of the rib structure in the second region, the first region is disposed in the vicinity of the raised portion, and the second region is outside the first region. Has been placed.

  According to the present invention, heat from the heat-generating component can be radiated by the rib structure formed in the first region, and the strength of the support member can be ensured by the rib structure formed in the second region. For this reason, the thickness of the support member can be reduced, and as a result, the electronic control device can be reduced in size, thickness, and heat dissipation.

1 is an external perspective view showing an embodiment of an electronic control device of the present invention. The perspective view of the II-II line cross section in FIG. II-II sectional view taken on the line of FIG. FIG. 3 is an enlarged view of the vicinity of a heat dissipation component in FIG. 2. FIG. 3 is a perspective view of the base illustrated in FIG. 2. FIG. 6 is a top view of the base illustrated in FIG. 5. The perspective view of the conventional base shown as the comparative example 1. FIG. The perspective view of the conventional base shown as the comparative example 2. FIG. The perspective view of the conventional base shown as the comparative example 3. FIG. The comparison figure of the fluctuation range of the distance L between a heat-emitting component and a protruding part. FIG. 3 is a comparison diagram of temperatures of heat-generating components. The perspective view of the base which concerns on the modification 1 of Embodiment 1. FIG. The top view from the upper part of FIG. FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. A contrast diagram of the void occurrence probability. The top view from the upper direction of a base concerning the modification 2 of Embodiment 1. FIG. FIG. 6 is an enlarged cross-sectional view of the vicinity of a heat dissipation component according to Modification 3 of Embodiment 1. The perspective view of the base which concerns on Embodiment 2 of this invention. FIG. 19 is a cross-sectional view of the base shown in FIG. 18 taken along line XIX-XIX. The perspective view of the base which concerns on the modification 1 of Embodiment 2 of this invention. FIG. 21 is an enlarged perspective view of the base shown in FIG. 20 as viewed from the direction of the arrow XXI. The perspective view of the base which concerns on the modification 2 of Embodiment 2 of this invention. FIG. 23 is an enlarged perspective view of the base shown in FIG. 22 as viewed from the direction of arrow XXIII.

--Embodiment 1--
[Overall structure of electronic control unit]
Hereinafter, an embodiment of an electronic control device according to the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view showing an embodiment of an electronic control device of the present invention, FIG. 2 is a perspective view taken along line II-II in FIG. 1, and FIG. 3 is II-II in FIG. It is line sectional drawing.
The electronic control device 1 illustrated in FIG. 1 can be applied to, for example, engine control, motor control, automatic transmission control, and the like of vehicles such as automobiles and railways. The electronic control device 1 includes a case 30 composed of a base 10 and a lid 20, a circuit board 40 housed in the case 30 and mounted with a heat generating component 41, and a connector 60 for connecting an external device. And.

  The base 10 and the lid 20 are made of a metal material such as Mg (magnesium), magnesium alloy, Al (aluminum), aluminum alloy, or stainless steel, or a synthetic resin such as an epoxy resin or a polyimide resin.

  The base 10 (supporting member) includes a plurality of rib structures 50 formed on one surface of the thin flat main body 11, ridges 15, and side walls 12 formed in a rectangular ring shape on the peripheral edge of the main body 11. And a pair of fixing portions 13 formed to protrude from the side wall 12 on one side edge side to which the connector 60 of the side wall 12 is attached. The main body 11, the plurality of rib structures 50, the side walls 12, and the fixing portion 13 in the base 10 are integrally formed by forging, casting, molding, or the like.

  The side wall 12 has a U-shaped structure having an inner wall 12 a and an outer wall 12 b, and is formed higher than the height of the rib structure 50. Each fixing portion 13 is connected to the side wall 12 and is formed in a flat shape having a thickness substantially equal to the height of the side wall 12, and a penetration member (not shown) is inserted through a substantially central portion. A hole 13a is formed. The upper surface side of the main body 11 is opened. Details of the rib structure 50 will be described later.

  The lid 20 has a structure having a flat portion 21 and a peripheral edge portion 22 that cover the opened one surface side of the main body portion 11. The flat portion 21 includes a flat portion 21 a having a high height and a flat portion 21 b having a low height corresponding to the connector 60. The peripheral edge 22 is formed with a protrusion 22 a that is fitted between the inner wall 12 a and the outer wall 12 b of the side wall 12 of the base 10. By fitting the protruding portion 22a of the peripheral edge portion 22 of the lid 20 between the inner wall 12a and the outer wall 12b of the side wall 12 of the base 10, the base 10 and the lid 20 are integrated, and the case 30 is assembled. Alternatively, the base 10 and the lid 20 are integrated with each other by inserting and adhering a waterproof adhesive between the protruding portion 22a of the peripheral edge portion 22 of the lid 20 and the inner wall 12a and the outer wall 12b of the side wall 12 of the base 10. And the case 30 is assembled. The case 30 is fixed by inserting a fastening member such as a bolt through the through hole 13a of the fixing portion 13 of the base 10 and fastening it to the chassis or the like of the vehicle.

The circuit board 40 is made of, for example, a substrate material such as epoxy resin, glass fiber, and FR4, and may be a single-sided, double-sided, or multilayer board. On the surface and / or inside of the circuit board 40, although not shown, wiring patterns and connection terminal portions for electrical connection of electronic components to be mounted are formed.
The circuit board 40 is fixed to a boss portion 17 (see FIG. 5) provided on the base 10 by a fastening member (not shown).

  The heat generating component 41 mounted on the circuit board 40 is an electronic component necessary for controlling a device to be controlled, such as a memory, a microcomputer, and an ASIC (Application Specific Integrated Circuit). The form and type of the heat generating component such as a semiconductor element or a semiconductor package are not particularly limited. As package forms, for example, QFP (Quad Flat Package), BGA (Ball Grid Array), SOP (Small Outline Package), DIP (Dual Inline Package), LGA (Land Grid Array), QFN (Quad Flat No-Leaded) and so on.

A connector 60 is attached to the circuit board 40. The connector 60 includes a plurality of connector pins 62 attached to a connector case 61. The connector 60 is housed in the flat portion 21a where the height of the lid 20 is high.
As a material of the connector case 61, PBT (Polybutylenterephthalate), PPS (Polyphenylene sulfide), or the like is used. The connector pins 62 are made of a copper alloy such as phosphor bronze or brass.
One end of each connector pin 62 is electrically connected to the wiring pattern of the circuit board 40 by an electrode terminal group (not shown). When solder is used to electrically connect the connector pins and the circuit board, the surface of the connector pins 62 is preferably subjected to nickel (Ni) plating, tin (Sn) plating, or the like in order to increase the bonding strength of the solder. .
The other end of each connector pin 62 is exposed to the outside of the case 30 and can be connected to an external device via an electrical connection member such as a wire harness.

  In addition to the heat generating component 41, chip components such as a resistor and a capacitor (not shown) are mounted on the circuit board 40. The electronic component including the heat generating component 41 and the connector 60 are respectively connected by the electrode bonding structure 25 (see FIG. 4). The circuit board 40 is electrically connected to a wiring pattern (not shown). In this specification, the electrode bonding structure 25 is used as a general term for a bonding member that connects an external connection terminal of an electronic component including the heat generating component 41 or a connector pin 62 of the connector 60 and a wiring pattern of the circuit board 40. . The material of the member constituting the electrode bonding structure 25 is not particularly limited as long as it can be electrically and thermally connected, but solder or conductive paste is desirable. This is because a conductive material can be applied on the circuit board 40 by printing or a dispenser to establish electrical connection, and productivity is high. When solder is used, there is no particular limitation as long as the melting start temperature is higher than the curing temperature of the sealing material. Examples of solder include Sn (tin) and Au (gold) alloy, Sn (tin) and Pb (lead) alloy, Sn (tin) and Ag (silver) alloy, Sn (tin) and Ag (silver) And Cu (copper) alloy system, Sn (tin), Ag (silver), and Bi (bismuth) alloy system solder, and 5 wt% or less of In (indium), Ni (nickel), Sb (antimony), Bi What added (bismuth) etc. is used. The conductive paste is a mixture of a conductive material and an adhesive material. When the conductive paste is used, the conductive material is not particularly limited, but Ag (silver), Cu (copper), Sn (tin), Pb (lead), Al (aluminum), Pt (platinum), Au (gold) ) And the like, organic materials such as polyacetylene, carbon such as graphite, fullerene, and carbon nanotube, or carbon compounds, or two or more of them are used in combination. When a thermosetting resin is used as the adhesive component, it is not particularly limited, but an epoxy resin, an acrylic resin, a bismaleimide resin, or the like is used. When a thermoplastic resin is used as the adhesive component, a resin having a melting point of 250 ° C. or higher, such as thermoplastic polyimide, polyetherimide, or polyamideimide, is dissolved in an organic solvent having a boiling point of 100 ° C. or higher and 300 ° C. or lower. If it does not specifically limit. The shape of the electrode bonding structure 25 is not particularly limited to the shape, and may be arbitrarily selected such as a spherical shape or a lead shape.

[Heat dissipation structure]
4 is an enlarged view of the vicinity of the heat generating component 41 in FIG. 2, FIG. 5 is a perspective view of the base 10 illustrated in FIG. 2, and FIG. 6 is a top view of the base 10 illustrated in FIG. It is.
On the inner surface side of the main body 11 of the base 10, a raised portion 15 is integrally formed with the main body 11 so as to face the heat generating component 41 mounted on the circuit board 40 by the electrode bonding structure 25. As described above, a plurality of rib structures 50 are formed on the inner surface side of the main body 11 of the base 10, but the raised portions 15 are substantially flat with a uniform thickness higher than the height of the rib structures 50. Is formed. The height of the raised portion 15 is formed lower than the height of the side wall 12 and the height of the boss portion 17. Further, the height of the side wall 12 is formed to be higher than the height of the boss portion 17.

[Rib structure]
The base 10 has four regions in which rib structures 50 having different sizes or shapes are formed. FIG. 6 is a plan view showing the arrangement of the first region R1 to the fourth region R4.
The first region R1 is disposed in the vicinity of the raised portion 15. Each of the plurality of rib structures 50 formed in the first region R1 is formed in a so-called honeycomb shape in a regular hexagonal shape by the linear ribs 51, and has a closed space inside. Yes. The rib structure 50 is composed of six straight ribs 51, and each straight rib 51 is shared with the ribs 51 of the adjacent rib structure 50.
The first region R <b> 1 includes a rib structure 50 connected to the raised portion 15 and a rib structure 50 connected to the side wall 12. The rib structure 50 connected to the raised portion 15 or the side wall 12 has a deformed substantially regular hexagonal shape in which a part of the linear rib 51 is replaced with the raised portion 15 or the side wall 12. In the present specification, a regular hexagonal shape including a regular hexagonal shape and a substantially regular hexagonal shape is used.
The rib structure 50 formed in the first region R1 has the largest area of the circle inscribed in the closed space among the four regions.

  The second region R2 is disposed outside the first region R1. The rib structure 50 formed in the second region R2 is almost entirely formed in a regular hexagonal shape, that is, a so-called honeycomb shape. However, the area of the circle inscribed in the closed space of the rib structure 50 formed in the second region R2 is larger than the area of the circle inscribed in the closed space of the rib structure 50 formed in the first region R1. small. In other words, the arrangement interval of the rib structures 50 formed in the second region R2 is smaller than the arrangement interval of the rib structures 50 formed in the first region R1. That is, the density of the rib structures 50 arranged in the second region R2 is larger than the density of the rib structures 50 arranged in the first region R1, and thus the cross-sectional second moment is large.

  The third region R3 is disposed between the first region R1 and the second region R2. The rib structure 50 formed in the third region R3 is provided in a space between the outer peripheral side surface of the rib structure of the first region R1 and the outer peripheral side surface of the rib structure 50 of the second region R2. Has a substantially rhombus shape.

  The fourth region R4 is disposed in the space between the first region R1 and the side wall 12 and in the space between the second region R2 and the side wall 12. The rib structure 50 formed in the fourth region R4 has a triangular shape provided in a space between the rib structure 50 in the first region R1 and the side wall 12, or the rib structure 50 and the side wall 12 in the second region R2. It has a polygonal shape such as a trapezoid provided in the space between. The rib structure 50 formed in the third region R3 and the fourth region R4 has an area of a circle or an ellipse inscribed in the closed space, and the closed space of the rib structure 50 formed in the second region R2 Smaller than the area of a circle or ellipse inscribed in

  A heat conductive material 45 is disposed between the raised portion 15 of the base 10 and the heat generating component 41 mounted on the circuit board 40. The heat conductive material 45 is made of a mixture of a matrix resin and a thermally conductive filler, is in the form of grease or gel, has a thermal conductivity of 0.2 W / mK or more, and an elastic modulus at room temperature of 1 kPa to 1 MPa. I just need it. When the elastic modulus is high, when the circuit board 40 is fixed to the base 10, a large force is applied to the electrode bonding structure 25 that connects the heat generating component 41 to the circuit board 40, and the connection reliability of the electrode bonding structure 25 may be reduced. There is sex. When the elastic modulus of the heat conductive material 45 is less than 1 KPa, it is difficult to handle, and since the fluidity is large, it does not stay at the coated portion, and the heat dissipation is reduced. Specifically, a silicone resin, a urethane resin, or those filled with an inorganic filler may be used.

The elastic modulus indicates a longitudinal elastic modulus. It can be calculated from the storage modulus of dynamic viscoelasticity measurement or the initial slope of the stress-strain curve in a tensile test. Alternatively, a value three times the shear elastic modulus measured with a viscometer or the like may be used.
The heat conductive material 45 contacts both the heat generating component 41 and the raised portion 15 of the base 10. The heat conductive material 45 is preferably formed on the raised portion 15 by coating. By applying the heat conductive material 45, the heat generated from the heat generating component 41 is efficiently conducted to the base 10 to dissipate heat.

  Since the raised portion 15 of the base 10 is high, the cross-sectional second moment is large. That is, bending rigidity is large. Therefore, in the vicinity of the raised portion 15, in other words, in the first region R1, even if the area of the circle or ellipse inscribed in the rib structure 50 is increased and the sectional moment of the region is reduced, the raised portion The portion 15 can ensure bending rigidity. Further, the first region R1 includes a rib structure 50 connected to the side wall 12. The side wall 12 is formed to be higher than the thickness of the raised portion 15, and has a second sectional moment greater than that of the rib 51. Thus, since 1st area | region R1 contains the rib structure 50 connected with the side wall 12, the bending rigidity is reinforced by the part which the inscribed area is small.

  As described above, since the raised portion 15 of the base 10 is thick and is a flat portion having a substantially uniform thickness, the heat generated from the heat generating component 41 passes through the heat conductive material 45 and the raised portion 15. Conducted efficiently and dissipated. In the first region R <b> 1, natural convection is generated between the base 10 and the circuit board 40 due to the heat generated in the heat generating component 41 that is radiated through the heat conductive material 45 and the raised portions 15. When the flow of the natural convection is hindered, the portion locally becomes high temperature. Therefore, in order to prevent the flow of the natural convection from being hindered, that is, to improve the heat dissipation, it is formed in the first region R1. The rib structure 50 has the lowest density among the four regions.

  A larger bending moment is applied to the vicinity of the fixed portion 13 of the base 10 and the central portion side of the base 10 than the other portions. Therefore, the rib structure 50 formed in the second region R2 in the vicinity of the fixed portion 13 and in the central portion side of the base 10 has a rib structure 50 in which the area of a circle inscribed in the closed space is formed in the first region R1. And the cross-sectional secondary moment is increased. Thereby, the rigidity of 2nd area | region R2 shall be large, and the deformation amount of the base 10 can be made small. The fixed portion 13 is formed in a flat shape having a thickness substantially the same as the height of the side wall 12 and has a large second moment of section.

  The third region R3 and the fourth region R4 are respectively a space between the first region R1 and the second region R2, a space between the first region R1 and the side wall 12, or a second region R2 and the side wall 12 respectively. This is a rib structure 50 for connecting the spaces. As described above, the rib structure 50 formed in the third region R3 and the fourth region R4 has the area of the circle or ellipse inscribed in the closed space, the rib structure 50 formed in the second region R2. Is smaller than the area of a circle or ellipse inscribed in the closed space. Further, as illustrated in FIG. 6, the space between the first region R1 and the second region R2, the space between the first region R1 and the side wall 12, and the space between the second region R2 and the side wall 12 are The total area is small. Moreover, the area | region where the rib structure 50 formed in 3rd area | region R3 and 4th area | region R4 is formed continuously is narrow. For this reason, the influence of the third region R3 and the fourth region R4 on the deformation of the base 10 is small.

[Example]
Example 1 in which the electronic control device 1 corresponding to the above embodiment is implemented is shown below.
The heat generating component 41 is provided with leads 41a (see FIG. 4), and each lead 41a has a composition of Sn (tin) -3.0Ag (silver) -0.5Cu (copper) (unit: wt%). Then, it was joined to the circuit board 40 using solder. As the circuit board 40, FR4 (printed circuit board) having a size of 200 mm × 200 mm, a thickness of 1.6 mm, an in-plane equivalent thermal conductivity of 40 W / mK, and a vertical equivalent thermal conductivity of 0.4 W / mK is used. It was. As the base 10, a forged product having a composition of ADC 12 having a rib structure 50 and a raised portion 15 on a surface facing the circuit board 40 was used.
A grease-like silicone resin mixture having a thermal conductivity of 2.2 W / mK and an elastic modulus at room temperature of 0.05 MPa was applied on the raised portion 15 as the thermal conductive material 45. The circuit board 40 was fixed to the boss portion 17 with M3 stainless steel bolts, and the heat conductive material 45 and the heat generating component 41 were arranged in contact with each other. The distance between the circuit board 40 and the inner surface 11a of the main body 11 facing the circuit board 40 is 5 mm.

The raised portion 15 has an area of 12 mm × 12 mm and a thickness of 3 mm. Here, the thickness indicates a distance between the inner surface 11 a of the main body 11 of the base 10 and the upper surface 15 a of the raised portion 15. The rib structure 50 formed in the first region R1 of the base 10 has a regular hexagonal shape in which a diameter of a circle inscribed in the closed space is 10 mm. The height of the rib structure 50 is 1 mm, and the distance between the adjacent rib structures 50 and the center is 11 mm.
The vicinity of the fixed portion 13 of the base 10 and the center side of the base 10 are defined as a second region R2, and a rib structure having a higher density than the rib structure 50 formed in the first region R1 is formed in the second region R2. .

(Comparative Example 1)
As Comparative Example 1, an electronic control device having a base 91 illustrated in FIG.
In the base 91, a raised portion 15 having the same configuration as the raised portion 15 of the first embodiment of the present invention is formed on the inner surface of the main body portion 91A. However, the rib structure 50 is not provided. Other configurations are the same as those of the first embodiment.

(Comparative Example 2)
As Comparative Example 2, an electronic control device having a base 92 illustrated in FIG.
In the base 92, the raised portion 15 and fine irregularities 71 are formed on the inner surface of the main body 92A. The configuration of the raised portion 15 is the same as the raised portion 15 of the first embodiment of the present invention. The fine unevenness 71 has a structure in which convex portions and concave portions extending in a direction parallel to a straight line connecting the centers of the pair of fixing portions 13 are continuously arranged in a wave shape in a direction perpendicular to the extending direction. The cross section of each convex part is triangular. Other configurations are the same as those of the first embodiment.

(Comparative Example 3)
As Comparative Example 3, an electronic control device having a base 93 shown in FIG.
In the base 93, the raised portion 15 and fine irregularities 72 are formed on the inner surface of the main body portion 93 </ b> A. The configuration of the raised portion 15 is the same as the raised portion 15 of the first embodiment of the present invention. The fine unevenness 72 has a structure in which convex portions and concave portions extending in a direction perpendicular to a straight line connecting the centers of the pair of fixing portions 13 are continuously arranged in a wave shape in a direction perpendicular to the extending direction. The cross section of each convex part is triangular. Other configurations are the same as those of the first embodiment.

[Contrast of deformation and heat dissipation characteristics]
The amount of variation in the distance L (see FIG. 4) between the upper surface 15a of the raised portion 15 formed on the base 10 and the heat generating component 41 is measured with respect to Example 1 and Comparative Examples 1 to 3 of the present invention. I went and compared. As will be described later, the distance L between the upper surface 15a of the raised portion 15 of the base 10 and the heat generating component 41 is related to the bending rigidity of the base 10, the temporal change in heat dissipation, and the heat dissipation.
The temperature cycle test is a test in which the lifetime is accelerated and evaluated from the actual usage time by changing the ambient temperature of the electronic control device 1 at a constant period. A specific method of the temperature cycle test is shown below.

  As for the ambient temperature of the electronic control unit 1, the minimum holding temperature was −40 ° C., the maximum temperature was 120 ° C., and each holding time of the minimum temperature and the maximum temperature was 30 minutes. Moreover, the heat dissipation was evaluated according to the following procedure. The electronic control device 1 is placed in air at a temperature of 25 ° C. and a flow rate of 0.5 m / s, and the temperature of the heat generating component when the heat generating component generates 10 W is less than ± 0.5 ° C. compared to the temperature five minutes ago. The electronic control unit 1 was held until stabilized. The surface temperature of the heat-generating component at this time was measured and compared.

FIG. 10 illustrates the results of the temperature cycle test of the electronic control device of Example 1 employing the base 10 and Comparative Example 1, Comparative Example 2, and Comparative Example 3 employing the bases 91 to 93.
In FIG. 10, the vertical axis indicates the amount of fluctuation (unit: μm) of the distance L between the upper surface 15a of the raised portion 15 and the heat generating component 41 when the ambient temperature is changed from the minimum temperature of −40 ° C. to the maximum temperature of 120 ° C. Hereinafter, it is referred to as “variation amount of the distance L”.
The variation amount of the distance L was the largest in Comparative Example 1, and was the smallest in the order of Comparative Example 2, Comparative Example 3, and Example 1. The deformation amount of Comparative Example 1 in which neither the rib structure 50 nor the unevenness 71 and 72 is formed is the largest. The fluctuation amount of the distance L in Comparative Example 2 including the unevenness 71 extending in the direction parallel to the straight line connecting the pair of fixing portions 13 is the unevenness extending in the direction orthogonal to the straight line connecting the pair of fixing portions 13. It was larger than the fluctuation amount of the distance L of Comparative Example 3 including 72. From this, it can be seen that the load acting on the base 10 is greater than the load in the direction parallel to the straight line connecting the pair of fixing parts 13 in the direction perpendicular to the straight line connecting the pair of fixing parts 13.

  The fluctuation amount of the distance L in the electronic control device 1 of Example 1 of the present invention having the honeycomb-shaped rib structure 50 was smaller than any of the electronic control devices of Comparative Examples 1 to 3. In the case of Example 1, by adopting a regular hexagonal honeycomb structure in the first region R1 and the second region R2, the bending moment is increased by increasing the cross-sectional second moment in the region where bending stress acts greatly. It was confirmed that it could be enlarged.

  The increase in the amount of variation of the distance L is pushed out to the outer periphery of the raised portion 15 of the heat conductive material 45 provided between the heat generating component 41 and the upper surface 15a of the raised portion 15 in proportion to the increase in the number of cycles. Means that the amount increases. When the amount pushed out to the outer periphery of the raised portion 15 of the heat conductive material 45 increases, the heat dissipation performance decreases. That is, if the fluctuation amount of the distance L is large, the change in heat dissipation with time is large. From this result, it was also confirmed that by using the electronic control device 1 including the base 10 of Example 1 of the present invention, it is possible to suppress a change in heat dissipation over time.

[Contrast of heat dissipation]
FIG. 11 is a diagram showing the temperature (° C.) of each heat generating component 41 in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.
As shown in FIG. 11, the temperature of the heat generating component 41 was the lowest in Example 1. In the first embodiment of the present invention, the vicinity of the raised portion 15 in the base 10 is the first region R1, and the interval between the adjacent rib structures 50 is wide. Therefore, the heat generated from the heat generating component 41 causes a natural convection flow in which the high temperature region and the low temperature region circulate between the circuit board 40 and the inner surface of the base 10, and the high temperature heat is generated by the natural convection flow. The part 41 spreads in all directions. Further, an air flow generated by natural convection collides with a rib provided at a certain distance from the heat generating component 41, and the flow direction of the air flow is turned to the base 10 side. As a result, heat exchange is promoted and heat dissipation is improved. Since the temperature of the heat generating component 41 in Example 1 of the present invention was lower than the temperature of any of the heat generating components 41 in Comparative Examples 1 to 3, the action of the rib structure 50 was supported.

According to the embodiment described above, the following effects can be obtained.
(1) A first region R1 having a rib structure 50 having a closed space is formed in the vicinity of the raised portion 15 of the base 10. For this reason, the bending rigidity of the base 10 is increased, and natural convection is generated by the heat generated from the heat generating component 41, and the heat spreads in all directions of the base 10 by the natural convection, so that heat dissipation can be improved.
(2) A second region R2 having a diameter of a circle inscribed in the closed space of the rib structure 50 larger than that of the rib structure 50 in the first region R1 is formed outside the first region R1 and on the center side of the base 10. Formed. That is, the cross-sectional secondary moment in the region where the large bending moment acts is larger than the cross-sectional secondary moment in the first region R1. For this reason, even if the thickness of the main body 11 of the base 10 is reduced, the deformation amount of the base 10 can be reduced.

(3) The heat conductive material 45 is disposed between the raised portion 15 of the base 10 and the heat generating component 41 mounted on the circuit board 40. The heat generated from the heat generating component 41 by the heat conducting material 45 can be efficiently conducted to the raised portion 15 of the base 10. The thermal conductivity of the heat conductive material 45 is preferably 0.2 W / mK or more. Further, by setting the elastic modulus at room temperature of the heat conducting material 45 to 1 KPa or more and 1 MPa or less, when the circuit board 40 is fixed to the base 10, the load applied to the electrode bonding structure 25 of the circuit board 40 is reduced, and the electrode bonding is performed. The connection reliability of the structure 25 can be ensured.

(4) Since the height of the side wall 12 of the base 10 is larger than the thickness of the rib structure 50, the bending rigidity around the side wall 12 is increased even when the rib structure 50 in the first region R1 is connected to the side wall 12. be able to.
(5) Since the boss portion 17 has the same thickness as the side wall 12 in the base 10, the bending rigidity in the vicinity of the boss portion 17 can be increased.
(6) Since the fixed portion 13 of the base 10 is formed in a flat shape having the same thickness as the side wall 12 and a substantially uniform thickness, the sectional moment of inertia of the fixed portion 13 is increased, and the bending rigidity of the base 10 is increased. Will improve.
The rib structure 50 formed on the base 10 can be applied with various modifications, and an example thereof will be shown below.

[Modification 1 of Embodiment 1]
FIGS. 12-14 shows the modification 1 of Embodiment 1, FIG. 12 is a perspective view which shows the modification 1 of the rib structure formed in a base, FIG. 13 is the top surface from FIG. FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG.
The feature of the base 10 in the first modification is that each linear rib 51a in each rib structure 50A is formed so as to be gradually inclined toward the inner surface of the main body 11 of the base 10 so as to become wider. It is. That is, each rib 51a constituting the rib structure 50A is wider on the root side than on the top side. The inclination may be linear or curved. Each regular hexagonal rib structure 50A has a smooth surface with each corner curved in a conical shape. In the first modification, the configuration other than the above is the same as that of the first embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.

As described above, the rib structure 50A is a smooth surface whose corners are conically curved, and the side surface of the rib 51a constituting the rib structure 50A is inclined with respect to the main body portion 11. For this reason, the thermal radiation coating material 44 (refer FIG. 14) with a large emissivity can be efficiently formed in the inner surface of the main-body part 11 and the surface of 50 A of rib structures.
As one of the important matters in forming the heat radiation paint 44, an air layer is formed between the surface of the main body 11 and the heat radiation paint 44 and between the surface of the rib structure 50A and the heat radiation paint 44. It is mentioned that it is not formed. When an air layer is formed between the surface of the main body portion 11 and the heat radiation paint 44 and between the surface of the rib structure 50A and the heat radiation paint 44, the air layer becomes a heat insulating portion and heat is accumulated. . Further, when installed in an environment where a thermal load is repeated as in a temperature cycle, the heat radiation paint 44 is easily peeled off from the film formation surface. When the heat radiation paint 44 is peeled off from the film formation surface, if the heat conductivity of the heat radiation paint 44 is low, the heat radiation property may be deteriorated as compared to the case where the heat radiation paint 44 is not formed.

(Void occurrence probability)
For the modified example 1 of the example 1, the example 1, the comparative example 2 illustrated in FIG. 8, and the comparative example 3 illustrated in FIG. 9, the heat-dissipation paint 44 is formed, and the air layer (hereinafter referred to as void) is formed. ) Were compared.
The heat radiation paint 44 has a surface resistance value of 10 ¹³ Ω / sq. The viscosity is 2, 2000 Pa · S (measured with a rotary viscometer). The heat radiation paint 44 was applied to the inner surface of the base 10 including the surface of the rib structure 50A (or 50), and the degree of void generation probability was compared based on the number of voids generated in each test product.
FIG. 15 shows the test result of the void generation probability.
The presence or absence of voids was judged as having voids when a void having a diameter of 0.5 mm or more occurred between the base 10 and the heat radiation paint 44 when the heat radiation paint 44 was applied to the base 10. In FIG. 15, ◯ indicates that the void occurrence probability is less than 1%, Δ indicates that the void occurrence probability is 1% or more and less than 10%, and × indicates that the void occurrence probability is 10% or more.

From the test results, the occurrence probability of voids in Example 1 is smaller than Comparative Example 2 and Comparative Example 3 in which the unevenness 71 or 72 illustrated in FIGS. 8 and 9 is formed. Furthermore, in Modification 1 of Embodiment 1 illustrated in FIG. 12, the occurrence probability of voids is smaller than that of Embodiment 1 and less than 1%.
From this, in order to improve the heat dissipation of the base 10 by forming the heat-dissipating paint 44, the rib structure 50 shown in the first embodiment is less likely to generate voids than the comparative example 2 and the comparative example 3. It was confirmed that the occurrence probability of voids can be further reduced by using the rib structure 50A of the first modification of the first embodiment.

  Therefore, also in the first modification, the same effects as those of the first embodiment can be obtained, and the probability of voids can be reduced in improving the heat dissipation by applying the heat radiation paint 44 to the base 10. There is an effect.

[Modification 2 of Embodiment 1]
FIG. 16 is a plan view showing another modification example of the rib structure according to the first embodiment as viewed from above the base.
The base 10 illustrated in FIG. 16 includes three regions R1, R2, and R4.
The first region R1 is disposed in the vicinity of the raised portion 15. Each of the plurality of rib structures 50 </ b> B formed in the first region R <b> 1 is formed in a quadrangular annular shape by linear ribs 52. Each linear rib 52 constituting the rib structure 50B is shared with the ribs 52 of the adjacent rib structure 50B. The rib 52 has a notch 53 formed in a part in the length direction. In other words, the rib structure 50B has a plurality of notches 53 that communicate with the adjacent rib structure 50B.
That is, the rib structure 50 according to the first embodiment and the rib structure 50A according to the modification 1 have a completely closed space with respect to the outside, whereas the inner side of the rib structure 50B according to the modification 2 is partially However, the space is freed to the outside. However, also in the rib structure 50B in the modified example 2, the open portion by the notch 53 is small as viewed from the entire peripheral side portion, and the internal space is a substantially closed space. In this specification, the rib structure 50, 50A having a completely closed space with respect to the outside and the rib structure 50B opened in part are referred to as a closed rib structure.

  The first region R <b> 1 includes a rib structure 50 </ b> B connected to the raised portion 15 and a rib structure 50 </ b> B connected to the side wall 12. In the rib structure 50 </ b> B connected to the raised portion 15 or the side wall 12, a part of the linear rib 52 is replaced with the raised portion 15 or the side wall 12. The rib structure 50B formed in the first region R1 has the largest area of the ellipse inscribed in the closed space among the three regions.

  The second region R2 is disposed outside the first region R1, in other words, closer to the center of the main body 11 than the first region R1. The rib structure 50B formed in the second region R2 also has a quadrangular shape, and a notch 53 is formed in a part of the rib 52 and is open to the adjacent rib structure 50B. However, the area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the second region R2 is larger than the area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the first region R1. small. In other words, the arrangement interval of the rib structures 50B formed in the second region R2 is smaller than the arrangement interval of the rib structures 50B formed in the first region R1. That is, the density of the rib structures 50B arranged in the second region R2 is larger than the density of the rib structures 50B arranged in the first region R1, and thus the cross-sectional second moment is large.

The fourth region R4 is disposed in the space between the first region R1 and the side wall 12 and in the space between the second region R2 and the side wall 12. The rib structure 50B formed in the fourth region R4 also has a quadrangular shape, and a notch 53 is formed in a part of the rib 52 and is open to the adjacent rib structure 50B. The area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the fourth region R4 is smaller than the area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the first region R1. However, the area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the fourth region R4 is smaller than the area of the ellipse inscribed in the closed shape of the rib structure 50B formed in the second region R2. , Almost equal, large, or small.
Configurations other than those described above are the same as those in the first embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.
Therefore, also in the said modification 2, there exists an effect similar to the said Embodiment 1. FIG.

  In the second modification, the structure that does not include the third region R3 in the first embodiment is illustrated. However, also in the modification 2, you may make it provide 3rd area | region R3 between 1st area | region R1 and 2nd area | region R2.

  In the second modification, the area of the ellipse inscribed in the closed shape of the rib structure 50B in the fourth region R4 is substantially equal to, larger or smaller than the second region R2. The structure is also exemplified as a formed structure. However, the area of the ellipse inscribed in the closed space of the rib structure 50B formed in the fourth region R4 is larger than the rib structure 50B formed in the second region R2. You may do it.

  Furthermore, in the second modification, an inclined portion that gradually increases in width from the distal end side toward the root side may be integrally formed on the rib 52 that constitutes the rib structure 50B. Further, the corners of the rib structure 50B may be arcuate.

[Modification 3 of Embodiment 1]
FIG. 17 shows a third modification of the first embodiment and is an enlarged cross-sectional view in the vicinity of the heat generating component.
A feature of the third modification is that, in contrast to the first embodiment, the heat conducting material 45 has a structure in contact with the back surface of the circuit board 40 on which the heat generating component 41 is mounted.
In FIG. 17, the heat generating component 41 has a lead 41 a on the surface of the circuit board 40 opposite to the main body 11 of the base 10, in other words, on one side of the lid 20. It is bonded and mounted on the wiring pattern.
The heat conducting material 45 applied on the raised portion 15 of the base 10 is disposed so as to contact the back surface of the circuit board 400 corresponding to the region where the heat generating component 41 is mounted.

In order to enhance the heat dissipation effect of the heat generating component 41, it is preferable to use the heat generating component 41 having a heat spreader which is a structural member such as a metal for heat sink on the package surface. The circuit board 40 may also be provided with through-through-hole vias that are thermally coupled to the heat spreader. Furthermore, if a high thermal conductive material is filled in the through through-hole via, the efficiency of heat dissipation is further improved. As the high heat conductive material, an underfill material having heat conductivity, a solder material, a silver paste, or the like may be used. When the through-hole via is installed in the circuit board 40, the area of the raised portion 15 is preferably equal to or larger than the installation area of the thermal via.
The center of the area of the raised portion 15 is arranged at a position substantially coincident with the center of the heat generating component 41.
In the structure illustrated in the third modification, heat generated from the heat generating component 41 can be conducted to the heat conducting material 45 through the circuit board 40.
Other configurations are the same as those of the first embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.
The modification 3 also has the same effect as the first embodiment.

--Embodiment 2--
18 is a perspective view of a base according to Embodiment 2 of the present invention, and FIG. 19 is a cross-sectional view of the base shown in FIG. 18 taken along the line XIX-XIX.
As in the first embodiment, the electronic control apparatus 1A according to the second embodiment is housed in a case 30 including a base 10A and a lid 20 as illustrated in FIGS. The circuit board 40 on which the heat generating component 41 is mounted and the connector 60 for connecting to an external device are provided. Here, the second embodiment is different from the first embodiment in that the base 10A has a different structure from the base 10 of the first embodiment.
Hereinafter, the second embodiment will be mainly described with respect to this difference, and the same reference numerals are assigned to the corresponding members in the configuration common to the first embodiment, and the description thereof is omitted.

The base 10A has two regions R1 and R2A in which rib structures 50C or 50D having different heights from the inner surface of the main body 11 of the base 10A are formed.
The first region R1 is disposed in the vicinity of the raised portion 15. Each of the plurality of rib structures 50C formed in the first region R1 is formed in a regular hexagonal annular shape by six straight ribs 55 in a so-called honeycomb shape, and has a closed space inside. doing. Each linear rib 55 constituting the rib structure 50C is shared with the rib 55 of the adjacent rib structure 50C. The first region R <b> 1 includes a rib structure 50 </ b> C connected to the raised portion 15 and a rib structure 50 </ b> C connected to the side wall 12. As in the rib structure 50 of the first embodiment, the rib structure 50C connected to the ridge 15 or the side wall 12 has a substantially regular six-dimensional shape in which a part of the straight rib 55 is replaced with the ridge 15 or the side wall 12 and deformed. It has a square shape.

The second region R2A is disposed outside the first region R1, in other words, closer to the center of the main body 11 of the base 10A than the first region R1. The rib structure 50D formed in the second region R2A is also formed in a regular hexagonal shape, a so-called honeycomb shape. In FIG. 18, the base 10 </ b> A is cut at an intermediate portion, and the rib structure 50 </ b> D shows only a half region.
The area of the circle inscribed in the closed space of the rib structure 50D formed in the second region R2A is the same as the area of the circle inscribed in the closed space of the rib structure 50C formed in the first region R1. . However, the rib structure 50D formed in the second region R2A has a height higher from the inner surface of the main body 11 of the base 10A than the rib structure 50C formed in the first region R1.

Here, the rib structure 50D adjacent to the rib structure 50D is referred to as a rib structure 50D ₀ , and the rib structure 50D adjacent to the rib structure 50C is referred to as a rib structure 50D ₁ . Six straight ribs constituting the rib structure 50D ₀ 56 are all the same height. On the other hand, in the rib structure 50D ₁ constituting six straight ribs 56, the ribs 56a to be connected to the rib structure 50C is towards the rib 55 of the rib structure 50C, gradually, a height lower inclined portion 57 have. That is, as illustrated in FIG. 19, the inclined portion 57 constitutes a connecting portion having a gentle upper surface between the rib 56 a and the rib 55.

The rib structure 50D _0, the entire straight ribs which is connected to the rib 55 of the rib structure 50C is towards the rib 55, gradually, also (see FIG. 18 having a sloping rib 58 and structure inclined ). Anyway, the rib structure 50D ₀ and the rib structure 50C, are connected so as to have a smooth upper surface.

The rib structure 50 </ b> C formed in the first region R <b> 1 is formed at a low height similarly to the rib structure 50 of the first embodiment, and the heat generating component 41 that radiates heat through the heat conductive material 45 and the raised portion 15. In this structure, natural convection due to heat generated in
Rib structure 50D ₀ and 50D _1, so formed higher than the rib structure 50C, the second moment is larger than the rib structure 50C. That is, bending rigidity is large. For this reason, even when the thickness of the base 10A is reduced, the deformation amount of the base 10A that generates a large bending stress can be reduced.
Therefore, according to the second embodiment, the same effects as the effects (1) to (6) in the first embodiment are obtained.

[Modification 1 of Embodiment 2]
20 and 21 show a first modification of the second embodiment of the present invention, FIG. 20 is a perspective view of the base, and FIG. 21 is an enlarged perspective view of the base shown in FIG. 20 as seen from the direction of the arrow XXI. is there.
The first modification of the second embodiment is different from the second embodiment in that a reinforcing portion 81 that protrudes in the thickness direction of the rib 56 is provided at an intermediate portion of the linear rib 56 constituting the rib structure 50D. is there.
The straight ribs 56 constituting the rib structure 50D are higher in height than the ribs 55 constituting the rib structure 50C, and thus the possibility of damage is greater. The strength of the rib 56 can be increased by the reinforcing portion 81.
Other configurations are the same as those in the second embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.

[Modification 2 of Embodiment 2]
22 and 23 show a second modification of the second embodiment of the present invention, FIG. 22 is a perspective view of the base, and FIG. 23 is an enlarged perspective view of the base shown in FIG. 22 as seen from the direction of arrow XXIII. It is.
The second modification of the second embodiment is different from the first modification of the second embodiment in that the straight ribs 56 and the root portions of the reinforcing portions 81 constituting the rib structure 50D are different from the first modification of the second embodiment. It is the point which provided the inclination part.
As shown in FIG. 23, the linear rib 56A constituting the rib structure 50D has a curved wide portion 85 at the base portion connected to the main body portion 11 of the base 10A. In addition, the reinforcing portion 81A has a curved wide portion 82 at the base portion connected to the main body portion 11 of the base 10A. The wide portions 85 and 82 may be linear inclined portions.
The rib 56A and the reinforcing portion 81A are integrally formed with the base 10A by forging, casting, molding, or the like.
Other configurations of the second modification of the second embodiment are the same as those of the first modification of the second embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.

  In the second modification of the second embodiment, since the ribs 56A and the root portions of the reinforcing portion 81A are formed wider, the bending rigidity becomes larger than that of the first modification of the second embodiment, and the deformation amount of the base 10A is further increased. Can be small.

  In the second modification of the second embodiment, since the wide portion 85 of the rib 56A and the wide portion 82 of the reinforcing portion 81A are inclined in a curved shape, the rib structure 50D is used to increase the emissivity of the base 10A. When the heat-dissipation paint 44 is applied to the front surface and the inner surface of the main body 11 of the base 10A, the probability of occurrence of voids can be reduced.

  As described above, according to each embodiment of the present invention, the heat dissipation of the heat generated from the heat generating component 41 is increased, the bending rigidity of the bases 10 and 10A is increased, and the amount of deformation is reduced. Can be made compatible. As a result, it is possible to provide an electronic control device having a highly reliable electrode connection structure that has a good heat dissipation and a small amount of bending deformation even if it is reduced in size and thickness.

  In the above embodiments, the rib structures 50 and 50A to 50D are exemplified as regular hexagonal shapes and quadrangular shapes. However, the rib structures 50 and 50A to 50D may have other polygonal shapes. Moreover, you may form circularly, an ellipse, etc. in the cyclic | annular form which does not have a corner | angular part.

  The raised portions 15 formed on the bases 10 and 10A are exemplified as a structure having a substantially uniform thickness as a whole. However, the raised portions 15 are formed by bending the main body portion 11 of the bases 10 and 10A and opening the bottom surface side. You may shape | mold into the convex shape which has a part.

  In the second embodiment, as illustrated in FIG. 16 as a second modification of the first embodiment, the rib structures 50C and 50D are formed in a polygonal shape other than a regular hexagonal shape, or in a shape provided with a notch 23. May be.

  In the first embodiment, any or all of the rib structures 50 formed in the second region R2 to the fourth region R4 are formed in the first region R1 as shown in the second embodiment. The height may be higher.

  The side wall 12 has a double side wall structure having an inner wall 12a and an outer wall 12b, but may have a structure having only one side wall. The thickness of the fixing portion 13 may be different from the height of the side wall 12. A rib structure similar to the bases 10 and 10A may be formed on the inner surface of the lid 20.

  In addition, the present invention can be applied with various modifications within the scope of the gist of the present invention. In short, in the support member that supports the circuit board on which the heat generating component is mounted, in the region corresponding to the heat generating member. What is necessary is just to provide the 1st rib structure with large heat dissipation, and to provide the 2nd rib structure whose cross-section secondary moment is larger than the 1st rib structure in the circumference | surroundings or the center side of the supporting member.

DESCRIPTION OF SYMBOLS 1, 1A Electronic controller 10, 10A Base 11 Main-body part 12 Side wall 13 Fixing part 15 Raised part 40 Circuit board 41 Heat generating component 44 Heat-dissipating coating material 45 Thermal conductive material 50, 50A-50D Rib structure 51, 52, 55, 56, 56a, 56A Ribs 81, 81A Reinforcing portions R1-R4, R2A First to fourth regions

Claims (20)

A circuit board;
A heat generating component mounted on the circuit board;
A support member for supporting the circuit board, including a main body part and a raised part formed on one surface of the main body part corresponding to the area of the circuit board on which the heat generating component is mounted;
A heat conductive material interposed between the raised portion of the support member and the area of the circuit board on which the heat generating component is mounted, or between the raised portion of the support member and the heat generating component;
The support member includes a first region formed of a plurality of closed-shaped rib structures formed on the one surface of the main body portion, and a second region, and the first member in the first region. The height of the rib structure is lower than the height of the rib structure in the second region, the first region is disposed in the vicinity of the raised portion, and the second region is the height of the first region. Electronic control device arranged on the outside. The electronic control device according to claim 1 .
The rib structure in the second region has an inclined portion whose height gradually decreases toward the first region at a connection portion with the rib structure in the first region, An electronic control device that is smoothly connected to the rib structure in the height direction. The electronic control device according to claim 1 .
The rib structure formed in the first region and the second region is formed by connecting a plurality of ribs, and is intermediate between at least one of the rib structures formed in the second region. An electronic control device in which a reinforcing part formed wider than the rib is formed in the part. The electronic control device according to claim 3 .
The ribs constituting the rib structure are electronically controlled such that at least a part of a base portion connected to the one surface of the main body portion is inclined or curved so as to gradually become wider toward the main body portion side. apparatus. The electronic control device according to claim 3 .
The reinforcing part formed in the first region is inclined or curved so that a base part side connected to the one surface of the main body part gradually becomes wider toward the main body part. . The electronic control device according to claim 5 .
An electronic control device, wherein a heat radiation paint having a higher emissivity than that of the material of the main body and the material of the rib structure is provided on the surface of the rib structure in the one surface and at least the first region of the main body. . The electronic control device according to claim 1.
The area of a circle or ellipse inscribed in the rib structure in the first region, said not greater than the area of a circle or ellipse inside the rib structure in the second region, the electronic control unit. The electronic control device according to claim 7 .
The support member further includes a third region interposed between the first region and the second region, and the third region includes the first region and the second region. At least one rib structure having a shape different from the rib structure formed in the region or having an area different from the area of the rib structure formed in the first region and the second region is formed. An electronic control device. The electronic control device according to claim 8 .
The support member surrounds the first region and the second region, has a side wall higher than the rib structure, and has a fourth region interposed between the side wall and the second region. The fourth region has a shape different from the rib structure formed in the second region, or has an area different from the area of the rib structure formed in the second region. An electronic control device in which at least one rib structure is formed. The electronic control device according to claim 9 .
An electronic control unit, wherein a part of the first region is directly connected to the side wall. The electronic control device according to claim 7 .
The electronic control device, wherein the cross-sectional second moment in the second region is larger than the cross-sectional second moment in the first region. The electronic control device according to claim 7 .
The electronic control device, wherein the rib structure includes at least one rib, and the rib is inclined or curved so that a base portion connected to the main body gradually becomes wider toward the main body. The electronic control device according to claim 12 , wherein
An electronic control device, wherein a heat radiation paint having a higher emissivity than that of the material of the main body and the material of the rib structure is provided on one surface of the main body and the surface of the rib structure. The electronic control device according to claim 1 .
The said rib structure formed in said 1st area | region and said 2nd area | region is an electronic control apparatus which is either a circle | round | yen, ellipse, or polygonal shape with which internal space was closed. The electronic control device according to claim 14.
The said rib structure formed in said 1st area | region and said 2nd area | region is an electronic control apparatus which has regular hexagon shape with which internal space was closed. The electronic control device according to claim 9 .
The support member is integrally formed with the side wall and has a fixed portion having a uniform thickness as a whole, and the thickness of the fixed portion is larger than the height of the rib structure. The electronic control device according to claim 1 , wherein the raised portion is formed to have a substantially uniform thickness, and the thickness of the raised portion is larger than the height of the rib structure. The electronic control device according to claim 1 .
The electronic control device, wherein the heat conductive material is interposed between the heat generating component and the raised portion. The electronic control device according to claim 1 .
The electronic control device, wherein the heat conducting material is interposed between the circuit board on which the heat generating component is mounted and the raised portion. The electronic control device according to claim 1 .
The electronic control device, wherein the thermal conductive material is a mixture of a resin having a thermal conductivity of 0.2 W / mK or more and an elastic modulus at room temperature of 1 KPa or more and 1 MPa or less and a thermal conductive filler.

Images