JP2012199451A - Electronic controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance heat dissipation performance of a heat generating electronic component mounted on a circuit board.SOLUTION: On the bottom wall 9 of a case 5 facing heat generating electronic components 2a-2c mounted on the back surface 3b of a circuit board 3, a clearance change portion 12 is formed so that the clearance between the bottom wall 9 and the back surface 3b of a circuit board 3 become smaller as it is more close to a circuit board support 11 which supports and fixes the circuit board 3. Since the clearance to the bottom wall 9 can become smaller for an electronic component 2a mounted closer to the circuit board support 11 in the clearance change portion 12, clearance between the electronic components 2a-2c mounted on the circuit board 3 and the bottom wall 9 of a case 5 can be prevented from increasing more than necessary to cause deterioration in the heat dissipation performance.

Description

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

  For example, Patent Document 1 discloses a pedestal that comes into close contact with the electronic component from the back side of the wiring substrate to a case where a wiring substrate having electronic components mounted on the surface thereof is attached, and heat dissipation that continues to the pedestal. There is disclosed a technique in which a protrusion is provided and heat generated in the electronic component is diffused from the pedestal to the wide range of the case through the heat dissipation protrusion.

JP 2009-158796 A

  Here, the wiring board needs to be attached to the case so that the mounted electronic component does not interfere with the case, and between the electronic component and the base of the case or the bottom surface of the case It is necessary to ensure a predetermined clearance.

  For this reason, the clearance between the electronic component and the case is set so that the electronic component does not interfere with the case even if the wiring board or the case is deformed for some reason.

  However, the amount of change in the clearance between the electronic component and the case due to the deformation of the wiring board or the case varies depending on the position in the case. For example, when setting the clearance between the electronic component and the inner wall surface of the case facing the electronic component mounting surface on which the electronic component is mounted, the electronic component mounting surface in a direction orthogonal to the electronic component mounting surface Based on the position where the amount of change in the clearance with the inner wall surface of the case is the largest, the clearance between the electronic component and the inner wall surface of the case becomes larger than necessary at the position where the amount of change in the clearance is small. .

  Therefore, if the clearance between the electronic component and the case is not set according to the amount of change in the clearance between the electronic component and the case, even if the pedestal is formed, the electronic component and the case There is a possibility that the clearance becomes large and the heat dissipation performance deteriorates.

  Therefore, the electronic control device of the present invention has a housing having a board facing wall facing the electronic component mounting surface of the circuit board, and a circuit board support part for supporting and fixing the circuit board, and the board facing wall is The clearance changing portion is formed such that the closer to the circuit board support portion, the smaller the clearance between the substrate facing wall and the electronic component mounting surface.

  According to the present invention, in the clearance changing portion of the substrate facing wall, the clearance between the substrate facing wall of the housing and the electronic component mounting surface can be set according to the distance from the circuit board support portion. It can be suppressed that the clearance between the electronic component mounted on the circuit board and the board facing wall becomes larger than necessary and the heat dissipation performance is deteriorated.

The disassembled perspective view which showed typically the schematic structure of the electronic controller which concerns on this invention. The disassembled perspective view which showed typically the schematic structure of the electronic controller which concerns on this invention. 1 is a perspective view of an electronic control device according to the present invention. Sectional drawing along the AA line of FIG. The perspective view of the case which comprises the housing | casing of the electronic control apparatus which concerns on this invention. Sectional drawing of the electronic control apparatus of a comparative example. The perspective view of the case of the electronic controller in 2nd Embodiment of this invention. The perspective view of the case of the electronic controller in 3rd Embodiment of this invention. The perspective view of the case of the electronic controller in 4th Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 to 5 are explanatory views schematically showing a schematic configuration of an electronic control device 1 according to the present invention, FIGS. 1 and 2 are exploded perspective views of the electronic control device 1, and FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a perspective view of the case 5 constituting the housing 8 of the electronic control device 1. FIG.

  The electronic control device 1 is mounted on an automobile and used for controlling an engine, a transmission, a brake, or the like. The electronic control device 1 is an electronic component 2 such as a heat-generating electronic component 2a to 2c or various electronic components 2d and 2e. Is a rectangular plate-like circuit board 3 mounted on the front surface 3a and the back surface 3b of the electronic component mounting surface, and an electric circuit attached to the circuit board 3 and formed on the circuit board and an external device are electrically connected The connector 4 to be connected, the case 5 in which the circuit board 3 is housed and fixed, the upper cover 6 that covers the circuit board 3 housed in the case 5, and the back surface 3 b of the circuit board 3 among the electronic components 2. The heat dissipating material 7 fills the space between the electronic components 2a, 2b, 2c and the case 5 without any gaps. The circuit board 3 is actually mounted with a plurality of various electronic components in addition to the illustrated electronic components 2a to 2e.

  A plurality (four in this embodiment) of electronic components 2a are mounted on the outer peripheral edge of one end (the left end in FIG. 1) side of the circuit board 3. A plurality (four in this embodiment) of electronic components 2b are mounted at positions on the inner peripheral side of the electronic component 2a on one end (the left end in FIG. 1) side of the circuit board 3. A plurality (three in this embodiment) of electronic components 2c are mounted on the inner peripheral side of the electronic components 2a and 2b on one end (the left end in FIG. 1) side of the circuit board 3. That is, as shown in FIG. 2, the heat-generating electronic components 2 a to 2 c are arranged in series in the short side direction of the circuit board 3, and are arranged on one end (the left end in FIG. 1) side of the circuit board 3. The electronic components 2a, 2b, and 2c are mounted in parallel in the order from the outer peripheral edge toward the inner peripheral side.

  Examples of the electronic component 2 mounted on the circuit board 3 include an IC, an FET (field effect transistor), a MOSFET (oxide film semiconductor field effect transistor), a transistor, a capacitor, a diode, and a resistor.

  The circuit board 3 is made of, for example, glass epoxy resin, and a connector 4 having two connection ports 4a and 4b connected to external connectors (not shown) is attached to the surface 3a of the circuit board 3, respectively. . In the present embodiment, the back surface 3 b side of the circuit board 3 is an attachment surface for the case 5.

  The circuit board 3 has four corners on the outer peripheral edge thereof fixed to a circuit board support portion 11 (described later) of the case 5 by screws 18. The circuit board 3 can be fixed to the case 5 with an adhesive.

  The case 5 and the cover 6 constitute the housing 8 of the electronic control device 1, and the case 5 has a substantially rectangular dish shape, and the cover 6 has a substantially rectangular dish shape deeper than the case 5. Presents.

  The case 5 is made of a metal material having excellent heat dissipation such as aluminum or iron. As shown in FIG. 5, the case 5 has a substantially rectangular plate-like bottom wall 9 corresponding to the substrate facing wall of the housing 8, and a bottom It has a side wall 10 erected on the outer peripheral edge of the wall 9 and a circuit board support portion 11 that supports the circuit board 3 with its upper end surface 11a. The side wall 10 is generally composed of side walls 10 a and 10 b along the short side direction of the bottom wall 9 and side walls 10 c and 10 d along the long side direction of the bottom wall 9.

  The bottom wall 9 faces the back surface 3b of the circuit board 3, and the clearance changing portion 12 formed so that the clearance C from the back surface 3b of the circuit board 3 becomes smaller as the circuit board support portion 11 is approached. Regardless of the positional relationship with the circuit board support part 11, there is a constant clearance part 13 where the clearance C with the back surface 3 b of the circuit board 3 is constant.

  The clearance changing portion 12 is formed in a portion facing the electronic components 2 a to 2 c mounted on the back surface 3 b of the circuit board 3. More specifically, the clearance changing portion 12 is formed on one side (left side in FIG. 1) of the bottom wall 9 over the entire length of the bottom wall 9 in the short side direction.

  In the clearance changing portion 12, the inner wall surface 9 a of the bottom wall 9 is concave with respect to the back surface 3 b of the circuit board 3, and the clearance C from the back surface 3 b of the circuit board 3 decreases as the side wall 10 a of the case 5 approaches. Therefore, in the clearance changing portion 12, the clearance C between the inner wall surface 9 a of the bottom wall 9 and the back surface 3 b of the circuit board 3 generally becomes smaller as the circuit board support portion 11 is approached.

  In the clearance changing portion 12 of the present embodiment, if the position of the bottom wall 9 in the long side direction (distance from the side wall 10a) is the same, the position of the bottom wall 9 in the short side direction (from the side wall 10c or 10d). Are different, the clearance C between the inner wall surface 9a of the bottom wall 9 and the back surface 3b of the circuit board 3 is the same.

  A portion other than the clearance changing portion 12 of the bottom wall 9 is a constant clearance portion 13. In the constant clearance portion 13, the inner wall surface 9 a of the bottom wall 9 becomes a plane parallel to the back surface 3 b of the circuit board 3 fixed to the case 5.

  A groove 14 that is continuous over the entire circumference of the side wall 10 is formed at the tip of the side wall 10. The groove 14 is filled with an adhesive material 15 (see FIG. 4 to be described later), and protrusions 25 (described later) provided on the cover 6 and the tips of engaging protrusions 4 c and 4 c provided on the connector 4. By inserting the side, the case 5 and the cover 6 are bonded and fixed, and are sealed fluid-tight so that foreign matter such as moisture and dust does not enter the housing 8 from the groove 14. An adhesive (not shown) is also applied to a portion where a notch 23 (described later) provided in the cover 6 and a connector 4 abut, and moisture or moisture is applied from the abutting portion into the housing 8. It is sealed fluid-tight so that foreign matter such as dust does not enter.

  The circuit board support part 11 is a columnar pedestal that protrudes from the four corners of the bottom wall 9 along the side wall 10 and is connected to the side wall 10 over the entire length. In other words, the circuit board support portion 11 is a columnar pedestal that protrudes (protrudes) from the side wall 10 toward the inside of the case 5.

  The circuit board support portion 11 is positioned in the vertical direction (vertical direction in FIG. 4 described later) of the circuit board 3 in the case 5 by placing the circuit board 3 on the upper end surface 11a.

  In addition, a screw hole 16 is formed in the upper end surface 11 a of the circuit board support 11 to which a screw 18 for fixing the circuit board 3 to the case 5 is screwed. Of the four circuit board support parts 11, the upper end surface 11 a of the two circuit board support parts 11 engages with the notch hole 3 c formed in the outer peripheral edge of the circuit board 3, and the circuit in the case 5 Positioning protrusions 17 for positioning the substrate 3 in the horizontal direction are formed.

  The case 5 is integrally provided with a pair of brackets 19 and 19 for mounting the electronic control device 1 to a vehicle body (not shown). In the present embodiment, the electronic control device 1 is attached to the vehicle body by through holes 19a and 19a penetrating vertically in the brackets 19 and 19, respectively.

  The cover 6 is made of a metal or a resin material, and has a substantially rectangular plate-shaped upper wall 20, a side wall 21 erected on the outer peripheral edge of the upper wall 20, and an upper wall 20 according to the outer shape of the connector 4. A connector housing portion 22 protruding from the side, a cutout portion 23 formed by cutting out a part of the side wall 21 so that one end of the connector 4 faces the outside, and a flange-like flange provided on the front end side of the side wall 21 And a protrusion 25 that is formed in the flange portion 24 and engages with the groove 14 at the tip of the side wall 10 when assembled with the case 5. When the cover 6 is assembled to the case 5 by the cutout portion 23, an opening is formed on one side surface of the housing 8, and one end of the connector 4 can protrude to the outside from this opening.

  The heat dissipating material 7 is provided so as to conduct heat generated by the plurality of electronic components 2 a to 2 c mounted on the back surface 3 b of the circuit board 3 to the bottom wall 9 of the case 5. The heat dissipating material 7 is a heat dissipating grease based on, for example, silicon, and has an insulating property. In addition, when the circuit board 3 is assembled to the case 5, the heat radiating material 7 is preferably liquid or pasty and solidified after assembly.

  Here, even when the circuit board 3 or the housing 8 is deformed by the influence of external force, ambient temperature change, ambient pressure change, etc., the position of the circuit board 3 in the housing 8 remains at the circuit board support portion 11. Since it is restrained and almost unchanged, the clearance between the electronic component mounting surface and the inner wall surface of the substrate facing wall in the direction orthogonal to the electronic component mounting surface of the circuit board 3 is closer to the circuit board support portion 11 that is a fixed point with respect to the housing 8. The amount of change in C is small. That is, since the position in the housing 8 is constrained and almost unchanged in the circuit board support part 11, even when the circuit board 3 or the housing 8 is deformed by the influence of external force, ambient temperature change, ambient pressure change, etc. The closer to the circuit board support portion 11, which is a fixed point with respect to the housing 8, the smaller the amount of change in the clearance C between the back surface 3 b and the inner wall surface 9 a of the bottom wall 9 in the direction orthogonal to the circuit board 3.

  The clearance C between the electronic components 2a to 2c mounted on the back surface 3b of the circuit board 3 and the inner wall surface 9a of the bottom wall 9 facing the back surface 3b of the circuit board 3 is deformed by the circuit board 3 or the casing 8. Even so, it is necessary to set the electronic components 2 a to 2 c so as not to contact the bottom wall 9 of the case 5, but in this way, the clearance changing portion 12 is close to the circuit board support portion 11. The closer the mounted electronic component 2a is, the smaller the clearance C from the bottom wall 9 which is the substrate facing wall can be made.

  The amount of change in the clearance C described above varies depending on the structure of the housing 8 in addition to the deformation of the circuit board 3. For example, when the case 5 is provided with a reinforcing part such as a rib, the rigidity of the case 5 changes (improves) by the reinforcing part, and therefore the clearance C is set in consideration of the presence or absence of the reinforcing part. do it. Further, in the circuit board 3, the portion to which the connector 4 is attached has a relatively high rigidity because a large number of pins from the connector 4 are fixed, but an external connector connected to the connector 4, If it is distorted by the stress acting on the wiring connected to the external connector, the amount of change in the clearance C may increase. Therefore, regarding the portion of the circuit board 3 to which the connector 4 is attached, when setting the clearance C, it is only necessary to consider that the amount of change in the clearance C is large due to external stress input. That is, in the portion of the circuit board 3 to which the connector 4 is attached, the clearance C may be set according to the magnitude of external stress expected to be input to the connector 4.

  In the configuration in which the clearance changing portion 12 is not set on the bottom wall 9 of the case 5 as in the electronic control device 30 of the comparative example shown in FIG. 6, the back surface 3 b of the circuit board 3 is arranged in the direction orthogonal to the circuit board 3. The electronic components 2a to 2c and these electronic components based on the position farthest from the circuit board support portion 11 that is the position where the change amount of the clearance C with the inner wall surface 9a of the bottom wall 9 is the largest (center of the case 5). If the clearance C with the inner wall surface 9a of the bottom wall 9 facing 2a to 2c is set, in the electronic components 2a and 2b close to the circuit board support portion 11, a clearance C with the inner wall surface 9a of the bottom wall 9 is required. As a result, the heat dissipation performance is deteriorated.

  More specifically, when the maximum amount of change δ of the clearance C between the back surface 3b of the circuit board 3 and the inner wall surface 9a of the bottom wall 9 in the direction orthogonal to the circuit board 3 is considered, the maximum change as the distance from the circuit board support 11 increases. Since the amount δ also increases, as shown by an arrow in FIG. 5, the maximum amount at the position in the center of the case 5 is larger than the maximum change amount δ1 of the clearance C at the outer peripheral edge of the circuit board 3 near the circuit board support 11. The amount of change δ2 becomes relatively large. Therefore, the back surface 3b of the circuit board 3 is located on the innermost side (when the maximum change amount δ2) when the change amount of the clearance C is maximized at the center of the case 5 (the circuit board support portion). The clearance C between each of the electronic components 2a to 2c and the inner wall surface 9a of the bottom wall 9 is determined so that the electronic component 2c (the furthest away from 11) does not contact the inner wall surface 9a of the bottom wall 9. Therefore, in the electronic components 2a and 2b close to the circuit board support portion 11, the clearance C between the bottom wall 9 and the inner wall surface 9a becomes larger than necessary, and the heat dissipation performance is deteriorated.

  Note that the electronic control device 30 of the comparative example shown in FIG. 6 schematically shows the case where the clearance changing portion 12 is not set on the bottom wall 9 of the case 5 in the above-described embodiment. Constituent elements identical to those in FIG. Also in this comparative example, the circuit board support portions 11 are provided only at the four corners of the bottom wall 9.

  On the other hand, in the electronic control device 1 of the present embodiment described above, the inner wall surface 9a of the bottom wall 9 and the circuit board become closer to the side wall 10a of the case 5 by the clearance changing portion 12 formed on the bottom wall 9 of the case 5. 3, the clearance C between the bottom wall 9 and the inner wall surface 9 a of the electronic component 2 a located on the side wall 10 a side of the case 5 can be reduced. That is, in the clearance changing portion 12, the closer to the circuit board support portion 11, the smaller the clearance C between the inner wall surface 9 a of the bottom wall 9 and the back surface 3 b of the circuit board 3, and thus the closer to the circuit board support portion 11. Thus, the clearance C between the electronic components 2a to 2c and the inner wall surface 9a of the bottom wall 9 can be set small.

  Accordingly, in the clearance changing portion 12, the clearance C between the electronic components 2a to 2c and the inner wall surface 9a of the bottom wall 9 becomes larger than necessary, and the heat dissipation performance of the electronic components 2a to 2c is deteriorated. This can be suppressed. In addition, it is possible to relatively reduce the amount of use of the heat dissipating material 7 interposed between each of the electronic components 2a to 2c and the inner wall surface 9a of the bottom wall 9, and the overall cost reduction of the electronic control device 1 is realized. be able to.

  In the above-described embodiment, the inner wall surface 9a of the bottom wall 9 in the clearance changing portion 12 can be a curved surface defined by a spherical surface. In this case, the clearance C between the electronic components 2a to 2c and the inner wall surface 9a of the bottom wall 9 can be set more strictly according to the distance from the circuit board support portion 11.

  Further, the clearance changing portion 12 can be appropriately set according to the position and number of the electronic components 2 mounted on the back surface 3 b of the circuit board 3. For example, the circuit board support portion 11 is provided on the bottom wall 9. If there are only four corners, they can be formed as shown in FIGS.

  In the case 40 of the second embodiment shown in FIG. 7, a clearance changing portion 41 of the bottom wall 9 is formed on a part of one side of the bottom wall 9 (left side in FIG. 1).

  The clearance changing portion 41 is formed such that the closer to the circuit board support portion 11, the smaller the clearance from the back surface 3 b of the circuit board 3. That is, in the clearance changing portion 41, the inner wall surface 9 a of the bottom wall 9 is concave with respect to the back surface 3 b of the circuit board 3, and the clearance from the back surface 3 b of the circuit board 3 decreases as the side wall 10 a of the case 5 approaches. . Therefore, in the clearance changing portion 41, the clearance between the inner wall surface 9 a of the bottom wall 9 and the back surface 3 b of the circuit board 3 generally becomes smaller as the circuit board support portion 11 is approached.

  In the case 50 of the third embodiment shown in FIG. 8, clearance changing portions 12 and 51 are formed on both sides of the bottom wall 9 (on the left and right sides in FIG. 1) over the entire length in the short side direction of the bottom wall 9. ing. The clearance changing portion 51 is formed such that the closer to the circuit board support portion 11, the smaller the clearance from the back surface 3 b of the circuit board 3. That is, in the clearance changing portion 51, the inner wall surface 9 a of the bottom wall 9 is concave with respect to the back surface 3 b of the circuit board 3, and the clearance from the back surface 3 b of the circuit board 3 decreases as the side wall 10 b of the case 5 approaches. . Accordingly, in the clearance changing portion 51, the clearance between the inner wall surface 9 a of the bottom wall 9 and the back surface 3 b of the circuit board 3 generally becomes smaller as the circuit board support portion 11 is approached.

  In the case 60 of the fourth embodiment shown in FIG. 9, the clearance changing portion 61 is formed on substantially the entire bottom wall 9 of the case 5. In the clearance changing portion 61, the inner wall surface 9a of the bottom wall 9 is a curved surface defined by a spherical surface. That is, in the clearance changing portion 61, the closer to the circuit board support portion 11, the smaller the clearance between the inner wall surface 9 a of the bottom wall 9 and the back surface 3 b of the circuit board 3.

  The technical ideas of the invention other than the claims that can be understood from the above-described embodiments are listed below.

[Claim a]
The electronic control apparatus according to claim 1, wherein the clearance changing portion is formed on one side of the substrate facing wall.

[Claim b]
The electronic control device according to claim 1, wherein the clearance changing portion is formed on both sides of the substrate facing wall.

[Claim c]
The electronic control device according to claim 3, wherein an inner wall surface of the substrate facing wall in the clearance changing portion is a curved surface defined by a spherical surface.

[Claim d]
The electronic control device according to claim 3, wherein the clearance changing portion is formed on the entire substrate facing wall, and an inner wall surface of the substrate facing wall is a curved surface defined by a spherical surface.

[Claim e]
3. The clearance changing portion according to claim 1, wherein the inner wall surface of the substrate facing wall is an inclined surface defined by a plane inclined at a predetermined angle with respect to the electronic component mounting surface. Electronic control device.

DESCRIPTION OF SYMBOLS 1 ... Electronic control apparatus 2a ... Electronic component 2b ... Electronic component 2c ... Electronic component 3 ... Circuit board 3b ... Back surface 5 ... Case 6 ... Cover 7 ... Radiating material 8 ... Housing 9 ... Bottom wall 10 ... Side wall 11 ... Circuit board support Part 12 ... Clearance changing part

Claims (3)

A circuit board on which heat-generating electronic components are mounted;
In an electronic control device having a housing in which the circuit board is accommodated,
The housing includes a substrate facing wall facing the electronic component mounting surface of the circuit board, and a circuit board support portion for supporting and fixing the circuit board in the housing.
The electronic control device according to claim 1, wherein the board facing wall includes a clearance changing portion formed such that a clearance between the board facing wall and the electronic component mounting surface becomes smaller as the circuit board supporting portion is approached.   The substrate facing wall has a constant clearance portion where a clearance between the substrate facing wall and the electronic component mounting surface is constant regardless of a positional relationship with the circuit board support portion, and the clearance changing portion is the substrate. The electronic control device according to claim 1, wherein the electronic control device is formed on a part of the opposing wall.   3. The electronic control device according to claim 1, wherein an inner wall surface of the substrate facing wall is formed to be a curved surface that is concave with respect to the electronic component mounting surface in the clearance changing portion. .

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