JP2011199092A - Electronic control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation of an electronic control device for vehicle.SOLUTION: The electronic control device 10 for vehicle includes a circuit board 20 mounting a heating element HE, and a housing 30 accommodating the circuit board 20. In the device, either the inner surface or the outer surface of the body 32 and the lid 34 constituting the housing 30 is subjected to surface treatment, e.g. coating, electrodeposition, or alumite treatment, of an insulating material which facilitates absorption and radiation of heat. Furthermore, continuous irregularities 34A of substantially same shape are formed in order to increase the surface area for receiving heat at least part of the inner surface of the lid 34 facing the heating element HE on the circuit board 20, i.e. the part facing the heating element HE. Heat generated from the heating element HE is transmitted to the lid 34 through the irregularities 34A, and dissipated from the outer surface thereof into the atmosphere.

Description

  The present invention relates to an electronic control device mounted on an automobile.

  An electronic control device mounted on an automobile includes a metal casing and a circuit board accommodated in the casing. Since the circuit board is mounted with a heating element such as a semiconductor switching element, a heat dissipation structure that moves the heat generated by the heating element to the housing and dissipates it from the outer surface of the housing to the atmosphere is adopted. Yes. In order to improve heat transfer from the heating element to the casing and heat dissipation from the casing to the atmosphere, as described in JP-A-2004-304200 (Patent Document 1), the surface of the casing is Techniques for performing processing have been proposed.

JP 2004-304200 A

However, in the conventional proposed technology, the surface treatment applied to the surface of the casing absorbs radiant heat from the heating element. Therefore, if the surface area of the casing facing the heating element is small, the heating element changes to the casing. There was a risk that heat transfer to
SUMMARY OF THE INVENTION In view of the problems of the prior art, an object of the present invention is to provide an automotive electronic control device with improved heat dissipation by reviewing a heat transfer structure from a heating element to a housing.

  For this reason, in the present invention, in an automotive electronic control device comprising a circuit board on which electronic components are mounted and a metal housing that houses the circuit board, at least one of the inner surface and outer surface of the housing And surface treatment that promotes heat absorption and radiation. Further, an unevenness for increasing the surface area is formed on at least a part of the inner surface of the housing facing the electronic component mounting surface of the circuit board.

  According to the present invention, the heat generated in the circuit board is transferred to the housing through the unevenness. At this time, since the unevenness increases the heat receiving area, the heat generated in the circuit board can be effectively transferred to the housing. And the heat transmitted to the housing is radiated from the outer surface to the atmosphere. Here, if the surface treatment is performed on the inner surface of the casing including the unevenness, absorption of heat generated in the circuit board can be promoted. On the other hand, if a surface treatment is applied to the outer surface of the housing, the heat radiation effect from the outer surface to the atmosphere can be enhanced. For this reason, the heat dissipation of the electronic control apparatus for motor vehicles can be improved.

It is a perspective view which shows an example of the electronic controller for motor vehicles. It is AA sectional drawing in FIG. It is a top view which shows the 1st modification of an unevenness | corrugation. It is sectional drawing which shows the other mounting method of a heat generating element. It is sectional drawing which shows the 2nd modification of an unevenness | corrugation. It is sectional drawing which shows the 3rd modification of an unevenness | corrugation. The 4th modification of an unevenness | corrugation is shown, (A) is the top view which looked at the cover from the back, (B) is the top view which looked at the cover from the table | surface

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of an automotive electronic control device (hereinafter referred to as “electronic control device”).
The electronic control device 10 is configured to include a circuit board 20 on which at least a heat generating element HE as an electronic component is mounted, and a housing 30 that houses the circuit board 20 therein. The housing 30 includes a main body 32 in which a concave portion 32 </ b> A for housing the circuit board 20 is formed, and a lid 34 that closes an opening of the main body 32. The main body 32 and the lid 34 are each made of an alloy mainly composed of aluminum (Al), magnesium (Mg), iron (Fe), or the like, and are manufactured by casting, pressing or cutting using a mold.

  The main body 32 has a substantially rounded quadrangular outer shape in plan view, and a concave portion 32A for accommodating the circuit board 20 is recessed from one surface to the other surface located on the opposite side. Female screws 32B for fastening the lid 34 are formed at the four corners of the main body 32 using screws 40 as an example of a fastening member. Further, as shown in FIG. 2, a boss having a female screw formed at the tip is used in the recess 32 </ b> A of the main body 32 in order to support and fix the circuit board 20 using a screw 50 as an example of a fastening member. A plurality of (pedestal) 32C are erected. Further, a circumferential groove 32D into which an elastic member 60 such as an O-ring, silicone, adhesive, etc. is fitted is formed in the periphery of the recess 32A of the main body 32 for the purpose of ensuring a seal with the lid 34. Is done. On the other hand, the lid 34 has a substantially rounded quadrangular outer shape in plan view, and insertion holes through which the screws 40 are inserted are respectively opened at the four corners.

  As shown in FIG. 2, the circuit board 20 is provided with a thermal via 20 </ b> A at a portion where the heating element HE is mounted, and contacts the bottom surface of the recess 32 </ b> A of the main body 32 with an adhesive 70 having heat conductivity interposed therebetween. is doing. Further, on the outer surface of the main body 32 with which the heat generating element HE contacts, known heat dissipating fins 32E are arranged in a row in order to dissipate heat transferred from the heat generating element HE to the main body 32 into the atmosphere. In place of the adhesive 70, heat conductive grease, a heat radiation sheet, or the like may be used.

At least one of the inner and outer surfaces of the main body 32 and the lid 34 is subjected to a surface treatment for promoting radiant heat absorption from the heating element HE and heat radiation from the housing 30. As an example of the surface treatment, alumite treatment such as application or electrodeposition of an insulating material can be applied.
In addition, as shown in FIG. 2, the inner surface of the lid 34 has a continuous substantially isomorphism that increases the surface area from one end to the other end in order to easily absorb the heat generated in the circuit board 20 including the heating element HE. Asperities 34A are formed. The unevenness 34A has a height such that the tip thereof does not contact the circuit board 20 including the heating element HE. Here, as an example of the unevenness 34A, for example, a fin shape, a sine wave shape, a rectangular wave shape, a sawtooth wave shape, a triangular wave shape, a protrusion shape including a cone shape, a pear skin shape, and the like can be adopted (hereinafter the same). ). Note that the unevenness 34A may be formed at least in a portion facing the heating element HE.

  It is desirable that the unevenness 34A of the lid 34 has a shape and a shape that improve at least one of the hot water flow when the lid 34 is cast and the rigidity of the lid 34. Further, as shown in FIG. 3, a flat portion 34 </ b> B that does not form the unevenness 34 </ b> A may be provided in order to improve the flow of hot water during casting, and for example, a rib that improves rigidity may be formed here. The number of flat portions 34B and ribs may be determined as appropriate in consideration of the dimensions of the lid 34 and the like. Further, in order to compensate for changes in the rigidity in the orthogonal direction of the lid 34 due to the ribs, for example, when the unevenness 34A of the lid 34 has a wave shape, it is desirable to provide the ribs so as to be orthogonal thereto. .

  According to such an electronic control device 10, heat generated by the heating element HE of the circuit board 20 is transmitted to the housing 30 through the following two paths, and is radiated from the outer surface to the atmosphere. The That is, the heat generated by the heating element HE is transmitted to the main body 32 through the thermal via 20A and the adhesive 70. Further, the heat generated by the heating element HE is transmitted to the lid 34 through the unevenness 34A. At this time, since the unevenness 34A that increases the surface area is formed on the inner surface of the lid 34, absorption of radiant heat from the heating element HE is promoted, and heat generated in the heating element HE is effectively transferred to the lid 34. can do. The heat transferred to the main body 32 and the lid 34 is radiated from the heat radiation fins 32E and the outer surface to the atmosphere. Here, if the surface treatment is performed on the inner surface of the lid 34 including the unevenness 34 </ b> A, absorption of heat generated by the heating element HE can be promoted. On the other hand, if surface treatment is performed on the outer surfaces of the main body 32 and the lid 34, the heat radiation effect from the outer surfaces to the atmosphere can be enhanced.

Further, by changing at least one of the inner surface or the outer surface of the main body 32 and the lid 34 from a flat surface to a multi-surface or a curved surface, it is possible to suppress the transmission of electromagnetic waves, and to reduce the influence of malfunction of the device due to the electromagnetic waves.
As shown in FIG. 4, the heating element HE may be attached to the back surface of the circuit board 20 facing the bottom surface of the recess 32 </ b> A of the main body 32. In this case, continuous substantially the same unevenness 32F that increases the surface area is formed on the bottom surface of the recess 32A. In short, irregularities 32F that increase the surface area are formed on at least a part of the inner surface of the housing 30 that faces the mounting surface of the heating element HE of the circuit board 20.

  Furthermore, in order to make it easy to receive heat from the heating element HE, the bottom surface of the recess 32A extends toward the heating element HE so as to be close to the heating element HE of the circuit board 20 (to the extent that it is not in contact). You may project and form the protrusion part 32G which has 32F. In this way, in addition to the operation and effect of the electronic control device 10 having the configuration shown in FIG. 2, the heat radiation from the surface of the circuit board 20 can be reduced by the heat radiation to the irregularities 32F. The surface of the circuit board 20 that has been installed and used exclusively for heat dissipation is not used for heat dissipation of the heat generating element HE, and other electronic components (including heat generating elements) can be mounted on the circuit board 20 for electronic control. The apparatus 10 can be downsized. Further, in this case, since the role of the active heat transfer and heat dissipation is reduced, the lid 34 uses a material having a small thermal conductivity such as a resin as the material of the lid 34 or is filled with a resin or the like instead of the lid 34. Then, the opening of the main body 32 may be closed.

Note that the tip of the protrusion 32G may be a flat surface for the purpose of reducing the clearance with the heating element HE. In this case, grease having heat conductivity or the like may be interposed between the tip of the protruding portion 32G and the heating element HE.
On the outer surface of the lid 34 corresponding to the region where the unevenness 34A is formed on the inner surface, continuous substantially the same unevenness 34C that increases the surface area may be further formed. The unevenness 34C formed on the outer surface of the lid 34 has the same phase shape as the inner surface unevenness 34A as shown in FIG. 5, or the shape symmetrical with the inner surface unevenness 34A as shown in FIG. And it is sufficient. That is, the unevenness 34C formed on the outer surface of the lid 34 only needs to have a shape corresponding to the unevenness 34A formed on the inner surface. In the electronic control device 10 shown in FIG. 4, irregularities may be further formed on the outer surface of the main body 32.

If the outer surface unevenness 34C is in phase with the inner surface unevenness 34A, the thickness of the lid 34 is reduced, so that heat dissipation from the outer surface can be improved while securing a surface area for heat absorption. it can. Further, if the outer surface unevenness 34C is axisymmetric with the inner surface unevenness 34A, the heat capacity is increased, so that the heat absorption performance can be improved.
Furthermore, as shown in FIG. 7, the formation direction of the unevenness 34A and the unevenness 34C formed on the inner surface and the outer surface of the lid 34 may be shifted by 90 degrees. In this way, the rigidity of the lid 34 can be improved while increasing the heat capacity. In addition, the unevenness 34A and the unevenness 34C are not limited to a configuration having a tolerance of 90 degrees, and it is only necessary to form an intersecting angle capable of improving the rigidity.
In the present embodiment, the configurations described in the drawings may be appropriately combined.

Here, technical ideas other than the claims that can be grasped from the embodiment will be described together with effects.
(A) The surface treatment is an alumite treatment such as coating or electrodeposition of an insulating material, or the like. The electronic control device for an automobile according to any one of claims 1 to 4.
According to the present invention, it is possible to easily realize a surface treatment that promotes heat absorption and radiation.

(B) The irregularities are a fin shape, a sine wave shape, a rectangular wave shape, a sawtooth wave shape, a triangular wave shape, a projection shape including a cone shape, and a pear skin shape. The electronic control device for automobiles according to any one of (a).
According to this invention, it is possible to easily realize unevenness with good heat absorption.

(C) The automobile electronic control device according to claim 2, wherein a flat portion for dividing the unevenness is formed in the housing, and a rib is formed in the flat portion.
According to this invention, the hot water flow at the time of casting a housing | casing can be improved by forming a flat part. Moreover, the rigidity of a housing | casing can be improved by forming a rib in a flat part.

(D) The irregularities formed on the outer surface of the casing are in phase with the irregularities formed on the inner surface of the casing, symmetrical with the irregularities formed on the inner surface of the casing, or the casing 5. The electronic control device for an automobile according to claim 4, wherein the electronic control device has a shape intersecting with the irregularities formed on the inner surface of the motor vehicle at a predetermined angle.
According to this invention, the heat capacity of the housing can be increased and the strength of the housing can be improved by appropriately selecting the shape of the irregularities formed on the outer surface of the housing.

DESCRIPTION OF SYMBOLS 10 Electronic controller 20 Circuit board 30 Case 32 Main body 32F Concavity and convexity 34 Lid 34A Concavity and convexity 34C Concavity and convexity HE Heating element

Claims (4)

A circuit board for mounting electronic components;
A metal housing that houses the circuit board therein;
In an automotive electronic control device comprising:
At least one of the inner surface and the outer surface of the housing is subjected to a surface treatment that promotes heat absorption and radiation, and at least a part of the inner surface of the housing facing the electronic component mounting surface of the circuit board has a surface area. An electronic control device for automobiles, characterized by forming increasing irregularities.   2. The electronic control device for an automobile according to claim 1, wherein the unevenness is formed in a portion and a shape that improve at least one of a hot water flow when casting the casing and rigidity of the casing.   The electronic control for automobiles according to claim 1 or 2, further comprising an uneven surface for increasing a surface area formed on an outer surface of the housing corresponding to a region where the uneven surface is formed on the inner surface. apparatus.   4. The automobile electronic control device according to claim 3, wherein the unevenness formed on the outer surface of the housing has a shape corresponding to the unevenness formed on the inner surface.