JP2016122867A - Mounting structure of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of an electronic component which can reduce influence on the electronic component due to warpage of a circuit board.SOLUTION: A mounting structure 1 of an electronic component has: a circuit board 2; an electronic component 3A mounted on one surface 2a of the circuit board 2; and a housing 4 for housing the circuit board 2 on which the electronic component 3A is mounted. The electronic component 3A is mounted on an end part 9 on the one surface 2a. The housing 4 adopts a structure including: a first pedestal part 11 thermally contacting with at least a part of the one surface 2a except the end part 9: and a second pedestal part 12 which is spaced further away from the one surface 2a than the first pedestal part 11 and thermally contacts with the electronic component 3A through a heat conduction member 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic component mounting structure.

  Patent Document 1 below discloses a mounting structure for electronic components according to an electronic control device mounted on a vehicle or the like. The electronic control device mounts an electronic component (heating element) such as a transistor, a power MOS (field effect transistor), and an IC (integrated circuit) on a circuit board, and accommodates the circuit board in a casing.

  In the prior art described above, a heat radiating sheet is used in order to radiate heat of the electronic component to the casing (casing) to suppress a temperature rise. This heat radiating sheet is interposed between the electronic component and the housing, ensures a heat radiating path for the electronic component, and enables efficient heat radiation. Moreover, in the said prior art, the latching | locking part is provided as a countermeasure which prevents poor contact, such as position shift of the heat-radiation sheet | seat by the vibration of the mounted vehicle.

Japanese Patent Laid-Open No. 2002-280776

  Incidentally, as shown in FIG. 2, the circuit board is fixed to the casing by screws or the like when assembled. In the above prior art, an electronic component requiring heat countermeasures is mounted in the central part of the circuit board, but the central part has a larger deformation amount due to the warping of the circuit board than the end part of the board fixed with screws. Become. The warping of the circuit board occurs when the vehicle vibrates or the board is assembled. Due to this influence, an excessive load is applied to the electronic component. In order to ensure the cooling performance in consideration of this warpage, a highly accurate design is required.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a mounting structure for an electronic component that can reduce the influence of the warp of a circuit board on the electronic component.

  In order to solve the above-described problems, the present invention includes a circuit board, an electronic component mounted on one surface of the circuit board, and a housing that houses the circuit board on which the electronic component is mounted. An electronic component mounting structure, wherein the electronic component is mounted on an end portion of the one surface, and the housing is in thermal contact with at least a part of the one surface other than the end portion. And a second pedestal portion that is further away from the one surface than the first pedestal portion and is in thermal contact with the electronic component via a heat conducting member. Is adopted.

  In the present invention, the first pedestal is configured to be in thermal contact with the one surface through the second heat conducting member.

  In the present invention, a configuration is adopted in which a second electronic component is mounted on the other surface of the circuit board opposite to the one surface that contacts the second heat conducting member. .

  Moreover, in this invention, the viscosity of the said 2nd heat conductive member used for the said 1st pedestal part employ | adopts the structure that the viscosity of the said heat conductive member used for the said 2nd pedestal part is higher. .

  Moreover, in this invention, the structure that the said 1st base part and said 2nd base part are arrange | positioned adjacent is employ | adopted.

In the present invention, the electronic component is mounted on the end of one surface of the circuit board. The end portion of the circuit board is a portion with a small amount of deformation as compared with the central portion with respect to warpage. For this reason, the influence by the curvature of a circuit board can be made small by mounting an electronic component (IC) in an edge part.
Further, in the present invention, the housing includes a first pedestal portion that is in thermal contact with at least a part of one surface other than the end portion of the circuit board, and the one surface from the first pedestal portion. A second pedestal that is spaced apart and is in thermal contact with the electronic component via the heat conducting member. The second pedestal portion is spaced apart from the first pedestal portion and thermally contacts the electronic component through the heat conducting member, thereby securing a heat radiation path to the housing and electronically by warping. Reducing impact and stress on parts. On the other hand, since the region other than the end portion (for example, the central portion) is held by the first pedestal portion closer to the second pedestal portion and deformation due to warpage is restricted, the other region (central portion) The influence given to the edge part (electronic component) by curvature can be made small.
Thus, according to the present invention, it is possible to reduce the influence on the electronic component due to the warping of the circuit board without requiring a highly accurate design.

It is sectional drawing which shows the mounting structure of the electronic component in 1st Embodiment of this invention. It is a top view which shows the structure of the housing | casing in 1st Embodiment of this invention. It is sectional drawing which shows the mounting structure of the electronic component in 2nd Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of an electronic component mounting structure according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

(First embodiment)
FIG. 1 is a cross-sectional view showing an electronic component mounting structure 1 according to a first embodiment of the present invention. FIG. 2 is a plan view showing the configuration of the housing 4 in the first embodiment of the present invention.
The electronic component mounting structure 1 according to the present embodiment relates to an electronic control device mounted on a vehicle. As shown in FIG. 1, an electronic component mounting structure 1 includes a circuit board 2, an electronic component 3 mounted on the circuit board 2, and a housing 4 that houses the circuit board 2 on which the electronic component 3 is mounted. Have.

  The circuit board 2 is a plate-like printed wiring board made of an insulating material such as a glass epoxy material or a glass composite material. An electronic component (first electronic component) 3A is mounted on one surface 2a of the circuit board 2, and an electronic component (second electronic component) 3B is mounted on the other surface 2b of the circuit board. ing. In FIG. 1, a member denoted by reference numeral 5 is a connector that is electrically connected to each electronic component 3, and is provided so as to protrude from the one surface 2 a of the circuit board 2 to the outside of the housing 4.

  The electronic component 3A is a heat generating component that generates heat during driving. The electronic component 3A of the present embodiment is an integrated circuit such as an ASIC, has a large amount of heat generation, and is relatively weak against vibration and stress. On the other hand, the electronic component 3B also generates heat during driving, but is a heat generating component such as a switching element and a resistor that are relatively resistant to vibration and stress as compared to the integrated circuit.

  A lid 6 is combined with the casing 4. As shown in FIG. 2, the circuit board 2 has a substantially rectangular shape in plan view with corners chamfered. The housing 4 has a plurality of screw holes 7 for screwing the four corners of the circuit board 2 (two of them are shown in FIG. 2). A screw member 8 (pressing member) shown in FIG. 1 is screwed into the screw hole 7. The screw member 8 is configured to fasten and fix the circuit board 2 to the housing 4.

  As shown in FIG. 1, the electronic component 3 </ b> A is mounted on the end 9 of the one surface 2 a of the circuit board 2. The end 9 is an end region in a direction along at least one of the sides of the circuit board 2 having a substantially rectangular shape in plan view. The end portion 9 of the present embodiment is a predetermined region at one (right side) end in a direction along the short side of the circuit board 2 (left and right direction in FIG. 1). In other words, the end portion 9 is a region in the vicinity of the screw member 8 to which the circuit board 2 is fastened and fixed.

  The housing 4 has two pedestal portions (first pedestal portion 11 and second pedestal portion 12) having different heights. Specifically, the housing 4 includes a first pedestal portion 11 that is in thermal contact with at least a part of the one surface 2a other than the end portion 9 (the central portion 10 in the present embodiment), and a first pedestal. The second pedestal portion 12 that is farther from the one surface 2 a than the portion 11 and is in thermal contact with the electronic component 3 </ b> A via the heat conducting member 21 is provided.

  The 2nd base part 12 is provided in the position facing the edge part 9 (electronic component 3A) of one surface 2a. The second pedestal portion 12 is separated from the one surface 2a according to the height of the electronic component 3A. Specifically, the second pedestal portion 12 is provided slightly apart from the height of the second pedestal portion 12 in consideration of an attachment error of the electronic component 3A. A heat conducting member 21 is interposed between the electronic component 3 </ b> A and the second pedestal portion 12.

  The housing 4 is formed from a metal member (for example, aluminum die cast) having high heat dissipation. The heat conducting member 21 forms a heat radiation path for transferring the heat of the electronic component 3 </ b> A to the highly heat radiating housing 4. The heat conducting member 21 of this embodiment has flexibility. Specifically, the heat conducting member 21 is made of heat dissipating grease having flexibility and a predetermined viscosity. As this heat radiation grease, silicon grease can be suitably used. The heat conductive member 21 is provided in the area | region which attached | subjected the dot of the 2nd base part 12 shown in FIG.

  The 1st base part 11 is provided in the position facing the center part 10 of one surface 2a, as shown in FIG. The first pedestal portion 11 is provided closer to the one surface 2 a than the second pedestal portion 12. The first pedestal portion 11 of the present embodiment is configured to be in thermal contact with one surface 2 a via a heat conductive member (second heat conductive member) 22. The heat conductive member 22 of this embodiment consists of a heat dissipation sheet. This heat dissipation sheet has an adhesive surface that adheres to one surface 2 a and the first pedestal portion 11. This heat conductive member 22 is provided in the area | region which attached | subjected the dot of the 1st base part 11 shown in FIG.

  The heat conducting member 22 forms a heat radiation path for transferring the heat of the circuit board 2 to the housing 4. As shown in FIG. 1, an electronic component 3 </ b> B is mounted on the other surface 2 b opposite to the one surface 2 a in contact with the heat conducting member 22 of the circuit board 2. Therefore, the heat conducting member 22 also serves as a heat dissipation path for transferring the heat of the electronic component 3B mounted on the other surface 2b to the housing 4 via the circuit board 2. According to this configuration, not only the electronic component 3A but also the circuit board 2 itself and the electronic component 3B can be protected against heat. Note that, unlike the heat conduction member 21, the heat conduction member 22 is not in direct contact with the electronic component 3, and thus a substance having a higher viscosity than the heat conduction member 21 can be used. In addition, since the 2nd base part 12 is spaced apart from one surface 2a rather than the 1st base part 11, and forms the recessed part, even if it uses the heat conductive member 21 with high flexibility, a heat conductive member 21 has a shape that is difficult to leak.

Next, the operation of the electronic component mounting structure 1 having the above-described configuration will be described.
As shown in FIG. 1, the electronic component 3 </ b> A is mounted on the end 9 of the one surface 2 a of the circuit board 2. The end portion 9 of the circuit board 2 corresponds to a portion with a small amount of deformation compared to the central portion 10 with respect to the warp of the substrate. For this reason, by mounting the electronic component 3 </ b> A on the end portion 9, the influence due to the warp of the circuit board 2 can be reduced. Therefore, according to the present embodiment, the resistance of the electronic component 3 </ b> A to the vibration of the circuit board 2 and the warp of the circuit board 2 that occurs when the circuit board 2 is assembled to the housing 4 is increased after the vehicle is mounted.

  Further, in the present embodiment, the housing 4 includes a first pedestal portion 11 that is in thermal contact with a part (center portion 10) of one surface 2a other than the end portion 9 of the circuit board 2, and a first There is a second pedestal portion 12 that is further away from the one surface 2a than the pedestal portion 11 and is in thermal contact with the electronic component 3A via a flexible heat conducting member 21. The second pedestal portion 12 is disposed away from the first pedestal portion 11 and thermally contacts the electronic component 3A through the heat conduction member 21 having flexibility, thereby radiating heat to the housing 4. Secure a route. In addition, the second pedestal portion 12 relaxes the impact and stress applied to the electronic component 3 </ b> A by the flexibility (cushioning property) of the heat conducting member 21.

  On the other hand, the central portion 10 of the circuit board 2 is held by the first pedestal portion 11 that is closer than the second pedestal portion 12. The 1st base part 11 controls the deformation | transformation by the said curvature by hold | maintaining the center part 10 regarding the curvature of a board | substrate. When the deformation amount at the central portion 10 is reduced by the restriction by the first pedestal portion 11, the deformation amount at the end portion 9 is also reduced. When the deformation amount at the end portion 9 is reduced, the influence of the warp on the electronic component 3A is reduced.

  In the present embodiment, the screw member 8 that presses the electronic component 3 </ b> A against the heat conducting member 21 is provided. The screw member 8 presses the electronic component 3 </ b> A against the heat conducting member 21 to bring them into close contact with each other. For this reason, it becomes difficult for the electronic component 3A to vibrate. Further, the screw member 8 presses the warp of the end portion 9 of the circuit board 2 due to the reaction force of the material (viscosity or the like) of the heat conducting member 21. For this reason, the curvature of the circuit board 2 becomes small.

  Thus, by providing the first pedestal portion 11 and the second pedestal portion 12 having different heights, the circuit board 2 is less likely to warp during assembly or vibration, and stress is not easily transmitted to the electronic component 3A. Become.

  Therefore, according to the above-described embodiment, the circuit board 2, the electronic component 3A mounted on the one surface 2a of the circuit board 2, the housing 4 that houses the circuit board 2 on which the electronic component 3A is mounted, The electronic component 3 </ b> A is mounted on the end 9 of the one surface 2 a, and the housing 4 has at least a part of the one surface 2 a other than the end 9. The first pedestal portion 11 that is in thermal contact, and the second pedestal portion that is spaced apart from one surface 2a of the first pedestal portion 11 and that is in thermal contact with the electronic component 3A via the heat conducting member 21. 12 can be used, and the influence of the warp of the circuit board 2 on the electronic component 3A can be reduced without requiring a highly accurate design.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 3 is a cross-sectional view showing an electronic component mounting structure 1 according to the second embodiment of the present invention.
As shown in FIG. 3, in the second embodiment, the first pedestal 11 has one surface 2 a of the circuit board 2 through the same heat conducting member 21 (heat radiation grease) as the second pedestal 12. And is in thermal contact.

When the circuit board 2 is assembled to the housing 4, a reaction force (grease reaction force) is applied from the heat conducting member 21 to the electronic component 3 </ b> A by pressing the screw member 8. It is preferable that the reaction force is small. . As shown in FIG. 2, when the 1st base part 11 and the 2nd base part 12 are arrange | positioned adjacently, the excess grease part of the heat conductive member 21 apply | coated to the 2nd base part 12 Protrudes to the adjacent first pedestal 11 side when the screw member 8 is pressed.
Therefore, according to the second embodiment, it is possible to prevent the grease reaction force of the heat conducting member 21 from being excessively applied to the electronic component 3A.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Mounting structure of electronic component, 2 ... Circuit board, 2a ... One side, 2b ... The other side, 3 (3A) ... Electronic component (1st electronic component), 3 (3B) ... Electronic component (2nd 4 ... housing, 8 ... screw member (pressing member), 9 ... end, 11 ... first pedestal portion, 12 ... second pedestal portion, 21 ... heat conduction member, 22 ... heat conduction Member (second heat conduction member)

FIG. 3 is a cross-sectional view showing an electronic component mounting structure 1 according to the second embodiment of the present invention.
As shown in FIG. 3, in the second embodiment, the first pedestal 11 has one surface 2 a of the circuit board 2 through the same heat conducting member 21 (heat radiation grease) as the second pedestal 12. And is in thermal contact. That is, the first pedestal portion 11 is in thermal contact with the one surface 2a through the same heat conductive member as the heat conductive member 21 applied to the second pedestal portion 12, and the first pedestal portion The heat conducting member 21 applied to the 11 and second pedestal parts 12 is applied separately to each pedestal part.

Claims (5)

An electronic component mounting structure comprising: a circuit board; an electronic component mounted on one surface of the circuit board; and a housing that houses the circuit board on which the electronic component is mounted.
The electronic component is mounted on an end of the one surface,
The housing is in contact with at least a part of the one surface other than the end portion and is in thermal contact with the first pedestal portion, and is separated from the one surface than the first pedestal portion. And a second pedestal portion that is in thermal contact with the electronic component via the electronic component mounting structure.   2. The electronic component mounting structure according to claim 1, wherein the first pedestal portion is in thermal contact with the one surface via a second heat conducting member.   3. The electronic device according to claim 2, wherein a second electronic component is mounted on the other surface opposite to the one surface that contacts the second heat conducting member of the circuit board. Component mounting structure.   The viscosity of the said 2nd heat conductive member used for a said 1st base part is higher than the viscosity of the said heat conductive member used for a said 2nd base part, The Claim 2 or 3 characterized by the above-mentioned. Electronic component mounting structure.   The electronic component mounting structure according to any one of claims 1 to 4, wherein the first pedestal portion and the second pedestal portion are arranged adjacent to each other.

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