JP6432918B1 - Circuit board housing - Google Patents

Abstract

An object of the present invention is to efficiently transfer heat generated by a heat generating component mounted on a circuit board enclosed in a housing to the housing. A heating circuit element is solder-connected to a surface of a circuit board that is hermetically clamped by a shelf step portion of a metal base member and a pinching pressing portion of a resin cover member. The heat transfer sheet 60A, in which the heat transfer sheet 60A is bonded via the surface heat transfer layer, the plurality of through-hole platings, and the back surface heat transfer layer, has a high thermal conductivity graphite sheet as an intermediate layer and has a thin film insulating layer attached on both sides. The heat transfer sheet 60A is pressed against the shelf 21 via the circuit board 40 to transfer heat to the base member 20A, and heat is dissipated from the back surface of the heat transfer sheet 60A to the bottom surface 23 of the base member 20A. [Selection] Figure 2A

Description

  The present invention relates to a circuit board housing case used as, for example, an in-vehicle electronic control device, and more particularly, to an improved heat transfer structure for efficiently transferring heat generated by a heat generating component mounted on the circuit board to the case. It is about.

A heat transfer member for transferring heat generated by a heat generating component mounted on a circuit board to a metal housing case and dissipating heat by the housing case includes heat transfer grease and / or a heat transfer sheet. It is carried out using together.
Note that a gap air layer is generated between the heating element and the housing due to dimensional errors in each part and dimensional variations of the actual product, and heat transfer grease is used to fill this air gap, and heat conduction of air Compared to a rate of 0.024 (W / m · K), the thermal conductivity of heat transfer grease (or heat release grease) filled with a heat conductive material is improved to, for example, 5 to 15 (W / m · K). Yes.
On the other hand, the main characteristics required for heat transfer members are high heat transfer, insulation and flexibility to obtain adhesion to the housing, but in general, materials with high thermal conductivity are conductive. However, it is difficult to satisfy both high heat conductivity and insulating properties at the same time.

For example, the thermal conductivity of iron, aluminum, and copper, which are conductive metal materials, is 75, 230, and 350 (W / m · K), and the thermal conductivity of graphite, which is a conductive nonmetallic material, is 1500 ( W / m · K), whereas the thermal conductivity of ceramics having a large thermal conductivity is 180 to 260 (W / m · K).
Therefore, while ensuring thermal conductivity and insulation by a composite heat transfer material in which an insulating sheet is bonded to a graphite sheet having a high thermal conductivity, an elastic contact layer is also provided for making flexible contact with the heat transfer counterpart surface. A material subjected to an additional elastomer treatment is also put into practical use, and the thermal conductivity of the added elastomer layer is, for example, 1.6 (W / m · K).

According to FIG. 4 of the following Patent Document 1 “Electronic Control Unit”, a resin substrate 20 mounted with a power MOSFET 31 serving as a heat generating circuit element is housed in a housing constituted by a cover 60 and a base (heat sink) 40. The heat generated by the heat generating circuit element is transferred to the base 40 through the heat radiating sheet 51. The heat radiating sheet 51 is an insulating sheet having a low thermal resistance including, for example, silicon. For example, a gel-like heat-dissipating grease based on silicon is applied between the heat-dissipating sheet 51 and the heat sink 40 which is a base member, and the fine conductivity gap is filled to increase the thermal conductivity. ing.
Therefore, the insulating function and the heat transfer function are shared, and the heat transfer structure mainly has a flexibility effect.

Further, according to FIG. 2 of the following Patent Document 2 “Heat Dissipation Sheet and Heat Dissipation Structure”, the heating element 13 is mounted on the substrate 14 housed in the housing 12, and the heat generated by the heating element 13 is generated by the elastic layer 23. Heat is transferred to the barrier layer 24 and the highly heat-conductive graphite (graphite) sheet 22, from which radiant heat is dissipated into the free space 12a.
Here, the elastic layer 23 is a thermoplastic elastomer such as silicone rubber having insulating properties and flexibility, and the barrier layer 24 is an insulating material such as polyethylene terephthalate. Therefore, it has a heat dissipation structure that shares the insulating function, heat transfer function, and flexibility function.

JP 2013-021348 A (FIG. 4, abstract, paragraph [0011]) JP 2007-012913 (FIG. 2, abstract, paragraphs [0021], [0033])

(1) Description of Problems of Prior Art The “electronic control unit” according to Patent Document 1 is provided with an insulating heat dissipating sheet between a circuit board on which a heat generating circuit element is mounted and a housing base serving as a heat dissipating medium. The heat conductivity of the heat-dissipating grease improves adhesion, but the heat conductivity of the heat-dissipating grease is 5 to 15 (W / m · K), which is extremely low compared to metal materials and graphite. In addition, the heat transfer characteristics due to fluctuations in heat transfer gap variations and hatching alterations greatly fluctuate, and there is a problem that incidental equipment required for coating work and work time loss occur.
On the other hand, since the “heat dissipating sheet and heat dissipating structure” according to Patent Document 2 is configured to dissipate heat from the graphite sheet to the space, the heat dissipating structure is provided through a heat-conducting housing. Therefore, there is a problem that two sets of heat dissipation structures that share the insulating function, the heat transfer function, and the flexibility function are required.
In addition, heat dissipation to the space in the housing has a problem that the heat transfer efficiency is remarkably reduced as compared with the heat transfer to the housing through the heat transfer member.

(2) Description of the object of the invention The object of the present invention is to transfer the heat generated by the heat generating circuit element mounted on the circuit board to the housing for housing the circuit board, and from the housing to the mounting member or the periphery thereof. In a heat transfer structure in which heat is transferred to the space to suppress the temperature rise of the heating circuit element, heat transfer with high thermal conductivity and electrical insulation, and a stable heat transfer contact surface in the heat transfer path are obtained. It is to provide a circuit board housing case that can be used.

A circuit board housing case according to the present invention is configured such that at least three sides of a rectangular circuit board on which a heat generating circuit element is mounted are hermetically sandwiched between a metal base member and a resin or metal cover member. A circuit board housing case,
The heat generating circuit element is integrally formed with a heat generating element, a heat sink, and a part of a connection terminal with a sealing resin, and one end of the connection terminal is soldered to a connection land provided on a surface layer of the circuit board,
The heat sink is solder-connected to a surface heat transfer layer provided on the surface layer of the circuit board, and a back surface heat transfer layer is provided on the back surface layer of the circuit board, and the surface heat transfer layer and the back surface The heat transfer layer is heat transfer coupled by a plating layer provided on the inner periphery of a plurality of through holes,
A heat transfer sheet is disposed in close contact with the back surface heat transfer layer of the circuit board,
The heat transfer sheet has a conductive heat transfer sheet as an intermediate layer, a first insulating sheet is bonded to a first surface that contacts the back heat transfer layer, and a second surface that is the opposite surface of the first surface. The second insulating sheet is adhered,
The circuit board is press-clamped between a press-clamping part constituted by a shelf step part provided at the outer edge part of the base member and a clamping pressing part provided at the outer edge part of the cover member. With
The heat transfer sheet is extended to the nipped portion being the nipped of the circuit board, is pressed against by the tray portion and the circuit board, the said base member via said trays portion It is placed in the heat transfer path between the heat sink and
The base member and the cover member are integrated by a plurality of fastening members provided on the outer periphery thereof, and the fastening contact surfaces are in close contact with each other,
The minimum gap dimension G1 between the shelf step part and the sandwiching pressing part is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board and the heat transfer sheet, and
The cover member is a resin molding material, and a plurality of projecting portions are erected on the sandwiching pressing portion, and a maximum gap dimension G2 between a tip end portion of the projecting portion and the shelf step portion is determined between the circuit board and the It is below the minimum thickness dimension Tmin of the total thickness dimension of the heat transfer sheet,
When the fastening contact surface is brought into intimate pressure contact with the fastening member, the tip portion of the projection is pressed and deformed, and the circuit board and the heat transfer sheet are pressed and sandwiched .

As described above, the circuit board housing case according to the present invention is configured by hermetically sandwiching the circuit board at the outer edge portion of the cover member and the metal base member, and the generated heat of the heat generating circuit element mounted on the circuit board. The heat transfer sheet is configured to transfer heat to the base member via the front heat transfer layer, through-hole plating, back heat transfer layer, and heat transfer sheet of the circuit board, and the heat transfer sheet is a conductive transfer material that provides high thermal conductivity. A thermal sheet is used as an intermediate layer, and first and second insulating sheets are bonded to both sides thereof.
The electrical insulation between the heat generating circuit element and the base member is achieved by the cooperation of the two layers of insulating sheets provided on the front and back of the conductive heat transfer sheet. The heat transfer sheet shares heat conduction in the direction parallel to the circuit board surface. In the heat transfer path, the contact surface between the heat transfer sheet on the back side of the circuit board and the heat transfer sheet is expanded to increase the thermal resistance of the insulating layer. Is suppressed, and the contact surface between the base member and the heat transfer sheet is suppressed in the thermal resistance at the contact boundary surface by the pressing clamping pressure.
Therefore, compared with the case where the heat transfer pedestal of the base member is provided on the back surface of the circuit board at the mounting position of the heat generating circuit element and the heat transfer heat is dissipated through the heat transfer grease, the bottom space of the base member is suppressed, In addition to reducing the size of the housing, it is possible to eliminate instability of heat transfer characteristics due to hatching and alteration of heat transfer grease.
In addition, heat is dissipated in the housing from the surface of the wide-area heat transfer sheet that expands the back of the circuit board corresponding to the mounting position of the heating circuit elements, thereby suppressing the temperature rise concentrated on the heating circuit elements. There is an effect that can be done.
In addition, the circuit board and the heat transfer sheet are pressed and sandwiched between the shelf step part via the protrusion provided on the sandwiching pressing part of the resin cover member, and the dimensions of each part Even when there is variation, the base member and cover member are fastened and fixed to each other by the fastening member. There is an effect that the obtained heat transfer characteristics can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the circuit board storage housing | casing by Embodiment 1 of this invention. It is sectional drawing by the 2A-2A line of the thing of FIG. It is an expanded sectional view of the local part 2B in FIG. 2A. It is sectional drawing of the circuit board clamping part by the 1st modification of the thing of FIG. It is sectional drawing of the circuit board clamping part by the 2nd modification of the thing of FIG. It is sectional drawing of the circuit board clamping part by Embodiment 2 of this invention. It is sectional drawing of the circuit board clamping part by the deformation | transformation form of the thing of FIG. 4A.

Embodiment 1 FIG.
(1) Detailed Description of Configuration First, FIG. 1 which is an overall configuration diagram of a circuit board housing case 100A according to Embodiment 1 of the present invention, and FIG. 2A which is a cross-sectional view taken along line 2A-2A of FIG. 2B, which is an enlarged cross-sectional view of the local portion 2B in FIG. 2A, will be described sequentially.
In FIG. 1, a circuit board housing case 100A includes a base member 20A made of aluminum die cast having mounting legs 26a to 26d on four sides, a circuit board 40 on which a plurality of circuit components including a heating circuit element 50 are mounted, The cover member 30 is made of a resin having a flange 37 on three outer peripheral wall portions, and the remaining outer peripheral wall portion of the cover member 30A is missing and provided on one side of the circuit board 40. The opening is sealed by the connector housings 90a and 90b.
The base member 20 </ b> A and the cover member 30 </ b> A are integrated using a fixing screw (not shown) and four screw holes 34 a to 34 d.
Further, the heat transfer sheet 60A provided on the back side of the mounting surface of the heat generating circuit element 50 and the waterproof seal material 70 filled in the inner surface of the flange 37 will be described later with reference to FIG. 2A.

In FIG. 2A, a rectangular circuit board 40 on which a plurality of circuit components including the heat generating circuit element 50 and connector housings 90a and 90b (see FIG. 1) are mounted is placed on the four shelf steps 21 of the rectangular base member 20A. It comes to be installed.
Three of the shelf steps 21 are opposed to the three pressing portions 31 provided on the cover member 30A, and the circuit board 40 is sandwiched by fastening screws (not shown).
And the waterproof protrusion part 22 is provided in the outer side of the four shelf step parts 21, The three waterproof protrusion parts 22 of them are opposed to the waterproof fitting part 32 provided in the outer edge of the cover member 30A. Thus, a seal gap filled with the waterproof seal material 70 is formed.
The waterproof fitting portion 32 on the remaining one side is fitted with a waterproof fitting portion (not shown) provided on connector housings 90a and 90b (see FIG. 1) mounted on one side of the circuit board 40, and One side is sandwiched between the base member 20A and the cover member 30A via the connector housings 90a and 90b.
Reference numeral 23 denotes a bottom surface portion of the base member 20A, and reference numeral 33 denotes a canopy portion of the cover member 30A.

In FIG. 2B, the heat generating circuit element 50 is formed by integrally forming the heat generating element 51, the heat sink 52, and the plurality of connection terminals 54 with the sealing resin 53, and the tip of the connection terminal 54 exposed from the sealing resin 53 is It is soldered to a connection land 44 which is a part of a copper foil pattern provided on the surface of the circuit board 40.
Further, the surface heat transfer layer 45a soldered to the heat sink 52 and the surface heat transfer layer 45a are electrically and thermally connected to the circuit board 40 through plating layers provided in the plurality of through holes 42. A combined back heat transfer layer 45b is provided.
The surface heat transfer layer 45a is coated with a solder resist film 46 except for the solder connection portion with the heat sink 52, so that the solder does not flow into the through hole 42. The heat transfer sheet 60 </ b> A includes a conductive heat transfer sheet 62 serving as an intermediate layer, and a first insulating sheet 61 and a second insulating sheet 63 bonded to both surfaces thereof.
The conductive heat transfer sheet 62 is made of a graphite material having a thickness dimension of, for example, 0.1 mm and a large thermal conductivity in the planar direction.
The first and second insulating sheets 61 and 63 are polyethylene terephthalate materials having a thickness of 5 μm, for example, and are flexible insulating materials.

The first insulating sheet 61 is a double-sided adhesive sheet, and a protective sheet is provided on the opposite surface of the intermediate layer. After the protective sheet is peeled off, the first insulating sheet 61 is adhered to the circuit board 40.
In this embodiment, the cover member 30A is a resin-molded material, and is more easily deformed than a metal member. When the base member 20A and the cover member 30A are fastened and fixed by a fastening member (not shown), Since the position of the surface and the planar position of the pressing portion of the circuit board 40 by the shelf step portion 21 and the holding pressing portion 31 are different, the circuit board 40 can be securely held even if there is a dimensional error of each portion. It has become.
Further, the circuit board 40 is a glass epoxy material having a thickness dimension of 1.6 mm, for example, and the entire thickness is increased at the position where the heat transfer sheet 60A is affixed, but this is also caused by the deformation of the cover member 30A. It is designed to be absorbed.

Next, FIG. 3A, which is a cross-sectional view of the circuit board holding portion of the circuit board housing case 110 </ b> A according to the first modification of FIG. 1, and the circuit board housing case 110 </ b> B according to the second modification of FIG. 1. 3B, which is a cross-sectional view of the circuit board clamping portion, will be described in detail with a focus on differences from FIG. 2A.
In FIG. 3A, a rectangular circuit board 40 on which a plurality of circuit components including the heat generating circuit element 50 and connector housings 90a and 90b (see FIG. 1) are mounted is placed on the four shelf steps 21 of the rectangular base member 20B. It comes to be installed.
Of these, the three shelf steps 21 are opposed to the three pressing portions 31 provided on the resin cover member 30B, and a plurality of protrusions 35 are integrally formed on the sandwiching pressing portion 31. Yes.
The base member 20B and the cover member 30B are integrated by a plurality of fastening members (not shown) provided on the outer periphery of the base member 20B and the fastening contact surfaces are in close contact with each other. The minimum gap dimension G1 with the pressing part 31 is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board 40 and the heat transfer sheet 60A, and the maximum gap between the tip part of the protruding part 35 and the shelf step part 21. The dimension G2 is equal to or less than the minimum thickness dimension Tmin of the total thickness dimension of the circuit board 40 and the heat transfer sheet 60A, and when the fastening contact surface is in close contact pressure contact with the fastening member, the tip of the protrusion 35 is pressed. The circuit board 40 and the heat transfer sheet 60A are pressed and clamped by being deformed.

3B, a rectangular circuit board 40 on which a plurality of circuit components including the heat generating circuit element 50 and connector housings 90a and 90b (see FIG. 1) are mounted is placed on the four shelf steps 21 of the rectangular base member 20B. It comes to be installed.
Of these, the three shelf steps 21 are opposed to the three pressing portions 31 provided on the resin cover member 30B, and a plurality of protrusions 35 are integrally formed on the sandwiching pressing portion 31. As in the case of FIG. 3A, when the fastening contact surface is brought into close pressure contact with the fastening member, the tip portion of the projection 35 is pressed and deformed so that the circuit board 40 and the heat transfer sheet 60B are pressed against each other. ing.
In addition, a seal gap in three directions filled with the waterproof seal material 70 is formed on the outer edge portion of the shelf step portion 21 and the sandwiching pressing portion 31 that sandwich the three rectangular sides of the circuit board 40. For example, the thickness is 0.3 mm, whereas the thickness of the heat transfer sheet 60B is 0.12 mm, for example.

Further, connector housings 90a and 90b are mounted on one side of the remaining square of the circuit board 40, and the waterproof sealing material 70 includes one side of the base member 20B, one side of the cover member 30B, and the connector housings 90a and 90b. An annular seal gap formed by the outer peripheral surface is filled and communicated with each other, and the heat transfer sheet 60B sandwiched and pressed by the sandwiching pressing portion 31 via the circuit board 40 in the shelf step portion 21 is at least one seal. An extension 60BB that enters the gap is provided.
As a result, the contact area between the heat transfer sheet 60B and the base member 20B is increased and the heat transfer characteristics are improved. When the heat generating circuit element 50 is arranged at the corner of the circuit board 40, the heat transfer characteristics are improved. The extended portion 60BB of the thermal sheet 60B is extended to the seal gap portion on two sides.

(2) Main points and features of the first embodiment As is apparent from the above description, the circuit board housing case according to the first embodiment of the present invention and its modifications is a rectangular circuit board on which the heating circuit element 50 is mounted. 40 is a circuit board housing case 100A / 110A / 110B constructed by sealing and sandwiching at least three sides of 40 by a metal base member 20A / 20B and a resin cover member 30A / 30B,
In the heat generating circuit element 50, a part of the heat generating element 51, the heat sink 52, and the connection terminal 54 are integrally formed with a sealing resin 53, and one end of the connection terminal 54 is connected to the surface layer of the circuit board 40. Soldered to land 44,
The heat sink 52 is solder-connected to a surface heat transfer layer 45a provided on the surface layer of the circuit board 40, and a back heat transfer layer 45b is provided on the back surface layer of the circuit board 40. The heat layer 45a and the back heat transfer layer 45b are heat transfer coupled by a plating layer provided on the inner periphery of the plurality of through holes 42,
Heat transfer sheets 60A and 60B are disposed in close contact with the back surface heat transfer layer 45b of the circuit board 40, and the heat transfer sheets 60A and 60B have the conductive heat transfer sheet 62 as an intermediate layer and the back surface heat transfer layer. The first insulating sheet 61 is bonded to the first surface that contacts the layer 45b, and the second insulating sheet 63 is bonded to the second surface that is the opposite surface of the first surface,
The circuit board 40 is formed by a press-and-clamping portion formed by a shelf step portion 21 provided at an outer edge portion of the base members 20A and 20B and a holding pressing portion 31 provided at an outer edge portion of the cover members 30A and 30B. And is pressed and clamped between
The heat transfer sheets 60 </ b> A and 60 </ b> B are extended to the press-clamping portion of the circuit board 40 that is press-clamped, and are press-contacted by the shelf step portion 21 and the circuit board 40, via the shelf step portion 21. Are arranged in a heat transfer path between the base members 20A and 20B and the heat sink 52.

The heat transfer sheets 60A and 60B are the conductive heat transfer sheet 62, which is a graphite material having a thickness dimension such that the thermal conductivity in the plane direction is 500 W / m · K or more, and the thin film sheet with a withstand voltage of DC 60 V or more. And the first and second insulating sheets 61 and 63,
The first insulating sheet 61 is provided with an adhesive layer on both surfaces thereof, one surface is bonded to the conductive heat transfer sheet 62, and the other surface is provided with a protective sheet that can be peeled and removed, The protective sheet is removed and attached to the circuit board 40,
The second insulating sheet 63 is provided with an adhesive layer on at least one surface, and this one surface is bonded to the conductive heat transfer sheet 62.
As described above, in relation to claim 4 of the present invention, the heat transfer sheet is configured by bonding the first and second insulating sheets to both surfaces of the conductive heat transfer sheet made of graphite, and is provided on the first insulating sheet. The formed protective sheet is removed and bonded to the circuit board.
Therefore, the assembly workability of the heat transfer sheet is improved, and even when no pressing force is applied between the circuit board and the heat transfer sheet, the adhesion with the circuit board is improved by the adhesive provided on the first insulating sheet. There is a feature that it is possible to improve and suppress the generation of thermal resistance at the contact surface.
The same applies to the second embodiment and its modifications.

The heat generating circuit element 50 is disposed at a square corner of the circuit board 40, and the heat transfer sheets 60A and 60B are extended to the shelf step portion 21 and the sandwiching pressing portion 31 on two orthogonal sides. Yes.
As described above, in relation to the fifth aspect of the present invention, the heat generating circuit element is disposed close to the corner portion of the rectangular circuit board, and the heat transfer sheet is interposed between the two orthogonal side shelf steps and the sandwiching pressing part via the circuit board. And it is clamped.
Accordingly, heat can be transferred from the shelf steps on the two sides to the cover member, and thus the heat transfer characteristics can be further improved.
The same applies to the second embodiment and its modifications.

The base member 20B and the cover member 30B are integrated by a plurality of fastening members provided on the outer periphery thereof, and the fastening contact surfaces are in close contact pressure contact with each other,
The minimum gap dimension G1 between the shelf step portion 21 and the sandwiching pressing portion 31 is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board 40 and the heat transfer sheets 60A and 60B, and
The cover member 30B is a resin molding material, and a plurality of protrusions 35 are erected on the sandwiching pressing portion 31.
The maximum gap dimension G2 between the tip of the protrusion 35 and the shelf step portion 21 is equal to or less than the minimum thickness dimension Tmin of the total thickness dimension of the circuit board 40 and the heat transfer sheets 60A and 60B.
When the fastening contact surface is brought into intimate pressure contact with the fastening member, the tip portion of the protrusion 35 is pressed and deformed so that the circuit board 40 and the heat transfer sheets 60A and 60B are pressed and sandwiched.
As described above, in relation to the first aspect of the present invention, the circuit board and the heat transfer sheet are pressed and sandwiched between the shelf step portion via the protrusion provided on the sandwiching pressing portion of the resin cover member. It has come to be.
Therefore, even if there is a variation in the dimensions of each part, in the state where the base member and the cover member are fastened and fixed to each other by the fastening member, the circuit board and the heat transfer sheet are securely pressed against the shelf step part by the deformation of the protruding part. It has the characteristic that it can pinch and can acquire the stable heat-transfer characteristic.

Three outer seal gaps filled with a waterproof seal material 70 are formed on the outer edge portion of the shelf step portion 21 and the sandwiching pressing portion 31 that sandwich the three rectangular sides of the circuit board 40, and
Connector housings 90a and 90b are mounted on one side of the remaining square of the circuit board 40. The waterproof sealing material 70 includes one side of the base member 20B, one side of the cover member 30B, and the connector housing 90a. The annular seal gap formed by the outer peripheral surface of 90b is also filled and communicated with each other,
In the shelf step portion 21, the heat transfer sheet 60 </ b> B that is sandwiched and pressed by the sandwiching pressing portion 31 via the circuit board 40 includes an extension portion 60 </ b> BB that enters a partial region of the three-side seal gap. Yes.
As described above, in relation to the third aspect of the present invention, the end portion of the heat transfer sheet is provided with the extension portion that enters the seal gap provided at the three outer edges of the base member and the cover member. The gap is filled with a waterproof sealing material.
Accordingly, the extension portion of the heat transfer sheet is pressed against the seal gap surface of the base member by the waterproof seal material, and the heat transfer area with respect to the base member is expanded, so that the heat transfer characteristics can be greatly improved. .
This can be configured similarly for the second embodiment.

Embodiment 2. FIG.
(1) Detailed Description of Configuration Next, FIG. 4A, which is a cross-sectional view of a circuit board holding portion according to Embodiment 2 of the present invention, and FIG. 4B, which is a cross-sectional view of a circuit board holding portion according to a modification of the embodiment of FIG. 2 will be described in detail with a focus on differences from FIG. 2A.
In each figure, the same numerals indicate the same or corresponding parts.
The main difference between the first embodiment and the second embodiment is that the base members 20C and 20D in the second embodiment include the heat transfer pedestal 24, and the heat generated by the heating circuit element 50 is generated by the base members 20C and 20D. In addition to the 20D shelf 21, the heat transfer pedestals 20C and 20D are also adapted to transfer heat.
Further, the cover member 30C in the second embodiment and its modified form is made of metal, but this can be made of resin as in the case of the first embodiment and its modified form. The cover members 30A and 30B in the case of the first embodiment and the modified embodiments thereof can be made of metal.

4A, the circuit board housing case 200A includes a metal base member 20C and a metal cover member 30C, and includes a plurality of circuit components including the heat generating circuit element 50 and connector housings 90a and 90b (FIG. 1). The rectangular circuit board 40 on which the reference is mounted is mounted on the four shelf steps 21 of the rectangular base member 20C.
Three of the shelf steps 21 are opposed to, for example, three clamping pressing portions 31 provided on a cover member 30C made of aluminum die cast or sheet metal, and the clamping pressing portion 31 has a plurality of protrusions. 36 is integrally molded.
The base member 20C and the cover member 30C are integrated by a plurality of fastening members (not shown) provided on the outer periphery of the base member 20C, and the fastening contact surfaces are in close contact with each other. The minimum gap dimension G1 with the pressing part 31 is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board 40 and the heat transfer sheet 60C, and the maximum gap between the tip part of the protrusion 36 and the shelf step part 21. The dimension G2 is equal to or less than the minimum thickness dimension Tmin of the total thickness dimension of the circuit board 40 and the heat transfer sheet 60C. When the fastening contact surface is in close contact pressure contact with the fastening member, the local portion of the circuit board 40 is compressed and deformed. Thus, the circuit board 40 and the heat transfer sheet 60C are pressed and sandwiched.

On the other hand, a heat transfer pedestal 24 is integrally formed on the bottom 23 of the base member 20C, and the heat transfer pedestal 24 and the heat transfer sheet 60C face each other with a gap of 0.2 mm, for example. The heat transfer grease 80 is applied to.
Therefore, in this embodiment, the heat generated by the heat generating circuit element 50 is transferred to the shelf step portion 21 and the heat transfer pedestal portion 24 of the base member 20C via the heat transfer sheet 60C. The temperature rise of the circuit element 50 can be suppressed.
In this embodiment as well, as in the case of FIG. 3B, the heat transfer sheet can be provided with an extension so as to enter the seal gap.

In FIG. 4B, which is a modified form of that of FIG. 4A, the circuit board housing case 200B is composed of a metal base member 20D and a metal cover member 30C, and the heat transfer sheet 60D used here includes An elastic sheet 64, which is a highly heat conductive resin material, is adhered, and the elastic sheet 64 has a thickness dimension of, for example, 0.5 mm.
Accordingly, the total thickness of the heat transfer sheet 60D and the elastic sheet 64 is 0.62 mm, and the shelf step portion 21 of the base member 20D is provided with a countersink step 25 having a depth of 0.4 mm. .
Thereby, when the base member 20D and the cover member 30C are integrally fixed by the fastening member, the elastic sheet 64 is compressed and deformed, and the compression dimension corresponds to a dimensional difference of 0.62-0.4 = 0.22 mm.

(2) Main points and features of the second embodiment As is clear from the above description, the circuit board housing case according to the second embodiment of the present invention and its modification is a rectangular circuit board on which the heating circuit element 50 is mounted. A circuit board housing case 200A; 200B configured by hermetically sandwiching and holding at least three sides of 40 by a metal base member 20C / 20D and a metal cover member 30C;
In the heat generating circuit element 50, a part of the heat generating element 51, the heat sink 52, and the connection terminal 54 are integrally formed with a sealing resin 53, and one end of the connection terminal 54 is connected to the surface layer of the circuit board 40. Soldered to land 44,
The heat sink 52 is solder-connected to a surface heat transfer layer 45a provided on the surface layer of the circuit board 40, and a back heat transfer layer 45b is provided on the back surface layer of the circuit board 40. The heat layer 45a and the back heat transfer layer 45b are heat transfer coupled by a plating layer provided on the inner periphery of the plurality of through holes 42,
Heat transfer sheets 60C and 60D are disposed in close contact with the back heat transfer layer 45b of the circuit board 40. The heat transfer sheets 60C and 60D have the conductive heat transfer sheet 62 as an intermediate layer, and the back heat transfer sheet 60C and 60D. The first insulating sheet 61 is bonded to the first surface that contacts the layer 45b, and the second insulating sheet 63 is bonded to the second surface that is the opposite surface of the first surface,
The circuit board 40 includes a press-contact clamping portion configured by a shelf step portion 21 provided at an outer edge portion of the base members 20C and 20D and a holding pressing portion 31 provided at an outer edge portion of the cover member 30C. While being pressed and clamped between,
The heat transfer sheets 60 </ b> C and 60 </ b> D are extended to the press-clamping portion of the circuit board 40 that is press-clamped, and are press-contacted by the shelf step portion 21 and the circuit board 40, via the shelf step portion 21. Are arranged in a heat transfer path between the base members 20C and 20D and the heat sink 52.

The base members 20C and 20D and the cover member 30C are integrated by a plurality of fastening members provided on the outer periphery thereof, and the fastening contact surfaces are in close contact pressure contact with each other,
The minimum gap dimension G1 between the shelf step part 21 and the sandwiching pressing part 31 is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board 40 and the heat transfer sheets 60C and 60D, and
The circuit board 40 is made of glass epoxy as a base material, and the cover member 30C is made of metal, and a plurality of protrusions 36 are formed on the sandwiching pressing portion 31.
The maximum gap dimension G2 between the tip of the protrusion 36 and the shelf step portion 21 is equal to or less than the minimum thickness dimension Tmin of the total thickness dimension of the circuit board 40 and the heat transfer sheets 60C and 60D.
When the fastening contact surface is brought into intimate pressure contact with the fastening member, the local portion of the circuit board 40 is compressed and deformed by the projection 36, and the heat transfer sheets 60C and 60D are pressed and sandwiched.
As described above, in relation to claim 2 of the present invention, the circuit board and the heat transfer sheet are press-clamped between the shelf step portion via the protrusion provided on the holding pressing portion of the metal cover member. It has come to be.
Therefore, even if there is a variation in the dimensions of each part, the circuit board and the heat transfer sheet are securely attached to the shelf step part by compressive deformation of the local part of the circuit board in a state where the base member and the cover member are fastened and fixed to each other by the fastening member. On the other hand, there is a feature that a stable heat transfer characteristic can be obtained by press-contacting.

A heat transfer pedestal portion 24 protruding from the bottom surface portion 23 is integrally formed on the bottom surface portion 23 of the base member 20C.
Heat transfer grease 80 is applied between the heat transfer pedestal 24 and the second insulating sheet 63 of the heat transfer sheet 60C.
As described above, in relation to claim 6 of the present invention, heat transfer grease is applied between the heat transfer pedestal protruding from the bottom surface of the base member and the second insulating sheet of the heat transfer sheet. .
Therefore, the heat generated by the heat generating circuit element is transferred to the shelf steps of the base member and the heat transfer pedestal through the heat transfer sheet so that heat is dissipated so that the temperature rise of the heat transfer pedestal does not become excessive. By performing heat dispersion, there is a feature that instability of heat transfer characteristics due to hatching and alteration of heat transfer grease can be suppressed.

A heat transfer pedestal 24 protruding from the bottom surface 23 is integrally formed on the bottom surface 23 of the base member 20D.
A heat conductive elastic sheet 64 is adhered to the outer surface of the second insulating sheet 63 of the heat transfer sheet 60D,
The shelf step portion 21 is provided with a countersunk step portion 25 into which the heat transfer sheet 60D whose thickness is increased by the elastic sheet 64 enters, and the elastic sheet 64 is compressed by at least 0.1 mm or more. Has a thickness dimension to deform,
The heat transfer sheet 60D is pressed and clamped by the clamping and pressing portion 31 via the circuit board 40 in the shelf step portion 21, and the elastic sheet 42 is connected to the countersunk step portion 25 and the heat transfer pedestal portion 24. Compression deformation between.
As described above, in relation to claim 7 of the present invention, between the heat transfer pedestal portion protruding from the bottom surface portion of the base member and the circuit board, the thickness is increased to perform compression deformation. A thermal sheet is interposed.
Therefore, the heat generated by the heat generating circuit element is transferred to the shelf steps and the heat transfer pedestal of the base member through the heat transfer sheet to improve the heat dissipation characteristics, so that the heat transfer sheet can be used without using heat transfer grease. It is possible to transfer heat to the heat transfer pedestal due to the compression deformation of this, and the assembly workability is improved.

  20A, 20B, 20C, 20D Base member, 21 Shelf step portion, 23 Bottom surface portion, 24 Heat transfer pedestal portion, 25 Counter feed step portion, 30A, 30B, 30C Cover member, 31 Nipping and pressing portion, 35 Protrusion portion, 36 Protrusion Part, 40 circuit board, 42 through hole, 44 connection land, 45a surface heat transfer layer, 45b back heat transfer layer, 50 heating circuit element, 51 heating element, 52 heat sink, 53 sealing resin, 54 connection terminal, 60A, 60B , 60C, 60D heat transfer sheet, 60BB extension, 61 first insulating sheet, 62 conductive heat transfer sheet, 63 second insulating sheet, 64 elastic sheet, 70 waterproof sealing material, 80 heat transfer grease, 90a, 90b connector housing , 100A circuit board housing case, 110A, 110B circuit board housing case, 200A, 200B circuit Plate housing case.

Claims (7)

A circuit board housing case configured by hermetically sandwiching and holding at least three sides of a rectangular circuit board on which a heat generating circuit element is mounted by a metal base member and a resin or metal cover member,
The heat generating circuit element is integrally formed with a heat generating element, a heat sink, and a part of a connection terminal with a sealing resin, and one end of the connection terminal is soldered to a connection land provided on a surface layer of the circuit board,
The heat sink is solder-connected to a surface heat transfer layer provided on the surface layer of the circuit board, and a back surface heat transfer layer is provided on the back surface layer of the circuit board, and the surface heat transfer layer and the back surface The heat transfer layer is heat transfer coupled by a plating layer provided on the inner periphery of a plurality of through holes,
A heat transfer sheet is disposed in close contact with the back surface heat transfer layer of the circuit board,
The heat transfer sheet has a conductive heat transfer sheet as an intermediate layer, a first insulating sheet is bonded to a first surface that contacts the back heat transfer layer, and a second surface that is the opposite surface of the first surface. The second insulating sheet is adhered,
The circuit board is press-clamped between a press-clamping part constituted by a shelf step part provided at the outer edge part of the base member and a clamping pressing part provided at the outer edge part of the cover member. With
The heat transfer sheet is extended to the nipped portion being the nipped of the circuit board, is pressed against by the tray portion and the circuit board, the said base member via said trays portion It is placed in the heat transfer path between the heat sink and
The base member and the cover member are integrated by a plurality of fastening members provided on the outer periphery thereof, and the fastening contact surfaces are in close contact with each other,
The minimum gap dimension G1 between the shelf step part and the sandwiching pressing part is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board and the heat transfer sheet, and
The cover member is a resin molding material, and a plurality of projecting portions are erected on the sandwiching pressing portion, and a maximum gap dimension G2 between a tip end portion of the projecting portion and the shelf step portion is determined between the circuit board and the It is below the minimum thickness dimension Tmin of the total thickness dimension of the heat transfer sheet,
When the fastening contact surface is brought into intimate pressure contact with the fastening member, the tip portion of the projection is pressed and deformed, and the circuit board and the heat transfer sheet are pressed and sandwiched.
Circuit board housing. A circuit board housing case configured by hermetically sandwiching and holding at least three sides of a rectangular circuit board on which a heat generating circuit element is mounted by a metal base member and a resin or metal cover member,
The heat generating circuit element is integrally formed with a heat generating element, a heat sink, and a part of a connection terminal with a sealing resin, and one end of the connection terminal is soldered to a connection land provided on a surface layer of the circuit board,
The heat sink is solder-connected to a surface heat transfer layer provided on the surface layer of the circuit board, and a back surface heat transfer layer is provided on the back surface layer of the circuit board, and the surface heat transfer layer and the back surface The heat transfer layer is heat transfer coupled by a plating layer provided on the inner periphery of a plurality of through holes,
A heat transfer sheet is disposed in close contact with the back surface heat transfer layer of the circuit board,
The heat transfer sheet has a conductive heat transfer sheet as an intermediate layer, a first insulating sheet is bonded to a first surface that contacts the back heat transfer layer, and a second surface that is the opposite surface of the first surface. The second insulating sheet is adhered,
The circuit board is press-clamped between a press-clamping part constituted by a shelf step part provided at the outer edge part of the base member and a clamping pressing part provided at the outer edge part of the cover member. With
The heat transfer sheet is extended to the press-clamping and clamping part of the circuit board and is press-contacted by the shelf step part and the circuit board, and the base member and the circuit board are interposed through the shelf step part. It is placed in the heat transfer path between the heat sink and
The base member and the cover member are integrated by a plurality of fastening members provided on the outer periphery thereof, and the fastening contact surfaces are in close contact with each other,
The minimum gap dimension G1 between the shelf step part and the sandwiching pressing part is not less than the maximum thickness dimension Tmax of the total thickness dimension of the circuit board and the heat transfer sheet, and
The circuit board is made of glass epoxy as a base material, the cover member is made of metal, and a plurality of protrusions are formed on the sandwiching pressing part,
The maximum gap dimension G2 between the tip part of the protrusion and the shelf step part is equal to or less than the minimum thickness dimension Tmin of the total thickness dimension of the circuit board and the heat transfer sheet,
When the fastening contact surface is brought into intimate pressure contact with the fastening member, a local portion of the circuit board is compressed and deformed by the protrusion 36, and the heat transfer sheet is pressed and sandwiched.
Circuit board housing. A circuit board housing case configured by hermetically sandwiching and holding at least three sides of a rectangular circuit board on which a heat generating circuit element is mounted by a metal base member and a resin or metal cover member,
The heat generating circuit element is integrally formed with a heat generating element, a heat sink, and a part of a connection terminal with a sealing resin, and one end of the connection terminal is soldered to a connection land provided on a surface layer of the circuit board,
The heat sink is solder-connected to a surface heat transfer layer provided on the surface layer of the circuit board, and a back surface heat transfer layer is provided on the back surface layer of the circuit board, and the surface heat transfer layer and the back surface The heat transfer layer is heat transfer coupled by a plating layer provided on the inner periphery of a plurality of through holes,
A heat transfer sheet is disposed in close contact with the back surface heat transfer layer of the circuit board,
The heat transfer sheet has a conductive heat transfer sheet as an intermediate layer, a first insulating sheet is bonded to a first surface that contacts the back heat transfer layer, and a second surface that is the opposite surface of the first surface. The second insulating sheet is adhered,
The circuit board is press-clamped between a press-clamping part constituted by a shelf step part provided at the outer edge part of the base member and a clamping pressing part provided at the outer edge part of the cover member. With
The heat transfer sheet is extended to the press-clamping and clamping part of the circuit board and is press-contacted by the shelf step part and the circuit board, and the base member and the circuit board are interposed through the shelf step part. It is placed in the heat transfer path between the heat sink and
On the outer edge of the shelf step portion and the sandwiching pressing portion that sandwich the three sides of the square of the circuit board, three seal gaps filled with a waterproof seal material are configured,
A connector housing is mounted on one side of the remaining square of the circuit board, and the waterproof sealing material is an annular shape constituted by one side of the base member, one side of the cover member, and an outer peripheral surface of the connector housing. The seal gap is also filled and communicated with each other.
In the shelf step portion, the heat transfer sheet that is sandwiched and pressed by the sandwiching pressing portion via the circuit board includes an extension portion that enters a partial region of the three-side seal gap.
Circuit board housing. The heat transfer sheet is the conductive heat transfer sheet, which is a graphite material having a thickness dimension with a thermal conductivity of 500 W / m · K or more in the plane direction, and the thin film sheet with a withstand voltage of DC 60 V or more. 1 and a second insulating sheet,
The first insulating sheet is provided with an adhesive layer on both surfaces thereof, one surface is bonded to the conductive heat transfer sheet, and the other surface is provided with a protective sheet that can be peeled and removed. The sheet is removed and adhered to the circuit board,
The second insulating sheet is provided with an adhesive layer on at least one surface, and this one surface is bonded to the conductive heat transfer sheet,
The circuit board housing case according to any one of claims 1 to 3 . The heating circuit element is disposed at a square corner of the circuit board, and the heat transfer sheet is extended to the shelf step part and the sandwiching pressing part on two sides orthogonal to each other,
The circuit board housing case according to any one of claims 1 to 4 . On the bottom surface of the base member, a heat transfer pedestal protruding from the bottom is integrally formed,
Heat transfer grease is applied between the heat transfer base and the second insulating sheet of the heat transfer sheet.
The circuit board housing case according to any one of claims 1 to 5 . On the bottom surface of the base member, a heat transfer pedestal protruding from the bottom is integrally formed,
A thermally conductive elastic sheet is bonded to the outer surface of the second insulating sheet of the heat transfer sheet,
The shelf step portion is provided with a countersink step portion into which the heat transfer sheet whose thickness is increased by the elastic sheet is inserted, and the elastic sheet has a thickness that performs a compressive deformation of at least 0.1 mm or more. Have dimensions,
The heat transfer sheet is pressed and clamped by the clamping and pressing portion via the circuit board in the shelf step portion, and the elastic sheet is compressed and deformed between the countersunk step portion and the heat transfer pedestal portion. ing,
Circuit board housing case according to claim 1 or 2.

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