JP2012253151A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device which is capable of cooling a heating element and can be easily miniaturized.SOLUTION: A bottom wall 12a of a housing as a heat dissipation member and a power module 22 as a heating element are bonded together via an adhesive layer B. The adhesive layer B contains a modified thermally conductive filler having an organic compound bonded to surfaces of inorganic particles, and an epoxy resin.

Description

  The present invention relates to an electronic device including a heat generating element and a heat radiating member attached to the heat generating element.

  In an electronic device including a heat-generating electronic component (heat-generating element) such as a power element or a power module, it is necessary to consider how to dissipate heat from the heat-generating element. For example, Patent Document 1 discloses a heat dissipation structure that improves heat dissipation of a heat generating element by interposing a heat spreader between the heat generating element and a heat dissipating member that dissipates heat of the heat generating element.

  Below, the example which actualized the heat dissipation structure using the heat spreader disclosed by patent document 1 to the electric compressor is demonstrated. Here, the housing of the electric compressor is a heat radiating member, and the power element mounted on the substrate of the motor drive circuit is a heat generating element. The motor drive circuit is a circuit for controlling the electric motor provided in the electric compressor.

  As shown in FIG. 3, a plate-shaped heat spreader 42 made of aluminum is fixed to the end wall 41 of the housing formed in a hollow cylindrical shape by screwing. The motor drive circuit board 43 is fixed to the heat spreader 42 by screws. The power element 44 mounted on the substrate 43 is fixed to the heat spreader 42 by screws so that one surface thereof is in contact with the heat spreader 42. In addition, heat radiation grease G is interposed between the housing end wall 41 and the heat spreader 42 and between the heat spreader 42 and the power element 44, and gaps between the members are filled with the heat radiation grease G. .

  According to the above configuration, the heat of the power element 44 is transferred to the end wall 41 of the housing while being dissipated by the heat spreader 42. The heat transferred to the end wall 41 of the housing is radiated by heat exchange with the refrigerant passing through the housing.

JP 2009-264172 A

  By the way, when adopting the heat dissipation structure using the heat spreader described above, it is necessary to insert a heat spreader between the heat dissipation member and the heat generating element, so that the installation space for the heat generating element and the substrate on which the heat generating element is mounted, etc. Must be secured larger than usual. Therefore, in the heat dissipation structure using the heat spreader, there is a problem that it is difficult to reduce the size of the installation portion of the heat generating element and the heat dissipation member, and thus to reduce the size of the electronic device.

  An object of the present invention is to provide an electronic device that can cool a heating element and can be easily reduced in size.

  In order to achieve the above object, the electronic device according to claim 1 includes a heat generating element, a heat radiating member attached to the heat generating element, and an adhesive layer that bonds the heat generating element and the heat radiating member, The gist of the adhesive layer is that it contains a modified thermally conductive filler having an organic compound bonded to the surface of the inorganic particles and an epoxy resin.

  According to a second aspect of the present invention, in the electronic device according to the first aspect, the organic compound includes a hydroxyl group, a carboxyl group, an amino group, a formyl group, a carbonyl group, an imino group, a thiol group, an ester bond, and an amide bond. The gist is to have at least one selected functional group or bonding site.

  The invention according to claim 3 is the electronic device according to claim 2, wherein the organic compound has at least one functional group selected from a hydroxyl group, a carboxyl group, and an amino group.

  According to a fourth aspect of the present invention, in the electronic device according to the second or third aspect, the modified thermal conductive filler combines the inorganic particles and the organic compound by a supercritical hydrothermal synthesis reaction. The gist is that it is a particle.

  According to the configuration of the first to fourth aspects of the present invention, the heat radiating member and the heat generating element are directly bonded via the adhesive layer without interposing a heat spreader between the heat radiating member and the heat generating element. Therefore, it is only necessary to secure an installation space that can accommodate the heat generating element and the substrate on which the heat generating element is mounted, and it becomes easier to reduce the installation space compared to a heat dissipation structure using a heat spreader. As a result, it is easy to reduce the size of the entire electronic device.

  In addition, an adhesive layer containing a modified thermal conductive filler in which an organic compound is bonded to the surface of inorganic particles and an epoxy resin is used as an adhesive layer that bonds the heat radiating member and the heating element. The modified thermally conductive filler has a higher affinity for the epoxy group of the epoxy resin than the inorganic particles whose surface is not modified. Therefore, in the adhesive layer, the heat resistance when heat is transferred from the modified thermally conductive filler to the epoxy resin or from the epoxy resin to the modified thermally conductive filler is reduced, and the heat between the modified thermally conductive filler and the epoxy resin is reduced. Conduction efficiency is improved. Thereby, the thermal conductivity of the whole adhesive layer is improved. In addition, since at least one functional group selected from a hydroxyl group, a carboxyl group, and an amino group has a particularly high affinity for the epoxy group of the epoxy resin, a modified thermal conductive filler in which an organic compound having the functional group is bonded. When it contains, the heat conductive efficiency between a modified heat conductive filler and an epoxy resin is raised more.

  Thus, according to the said structure, the heat conductivity of an contact bonding layer improves and it becomes possible to transmit the heat | fever of a heat generating element efficiently to a thermal radiation member. The heat transmitted to the heat radiating member is radiated from the heat radiating member to the outside. Therefore, it is possible to effectively dissipate the heat of the heating element without using a heat spreader.

  The invention according to claim 5 is the electronic device according to any one of claims 2 to 4, wherein the inorganic particles are made of an insulating material. According to the said structure, insulation can be provided to a contact bonding layer. In particular, when the heat generating element is a heat generating element having a terminal portion such as a lead frame exposed to the outside and the heat radiating member is a conductive heat radiating member, heat is generated by providing insulation to the adhesive layer. Discharge from the terminal portion of the element to the heat radiating member side can be suppressed.

  Invention of Claim 6 is an electronic device as described in any one of Claims 1-5, The volume fraction of the said modified thermal conductive filler in the said contact bonding layer is 30-90 volume%. This is the gist. According to the said structure, the heat conductivity of an contact bonding layer can be ensured more suitably.

  The gist of the invention described in claim 7 is that, in the electronic device according to any one of claims 1 to 6, a substrate on which the heating element is mounted is fixed to the heat dissipation member. According to the said structure, the fixing state of the heat generating element with respect to a heat radiating member can be stabilized.

  According to an eighth aspect of the present invention, in the electronic device according to any one of the first to seventh aspects, the heating element is used in a motor drive circuit of an electric compressor, and the heat dissipation member is an electric compressor. The gist of this is the housing. According to the above configuration, in the electric compressor, the heat of the heat generating element provided in the motor drive circuit can be radiated from the housing, and the motor drive circuit can be efficiently cooled.

  According to the electronic apparatus of the present invention, the heat generating element can be cooled and it is easy to reduce the size.

The schematic cross section which shows the outline | summary of the electric compressor of embodiment. Sectional drawing which shows the attachment structure of the motor drive circuit in the electric compressor of embodiment. Sectional drawing which shows the attachment structure of the motor drive circuit in the electric compressor of a prior art.

Hereinafter, an embodiment in which the present invention is embodied in an electric compressor will be described with reference to FIGS. 1 and 2.
First, the basic structure of the electric compressor C will be described.
As shown in FIG. 1, the housing H of the electric compressor C is a second aluminum tube having a bottomed cylindrical shape at the open end of an aluminum first housing 11 (left side in FIG. 1) having a covered cylindrical shape. It is formed by joining the housing 12 (right side in FIG. 1). In the housing H, the electric motor 13 is accommodated on the bottom wall 12 a side of the second housing 12, and drivingly connected to the electric motor 13 via the rotating shaft 14 on the bottom wall 11 a side of the first housing 11. The compression mechanism 15 is accommodated. The compression mechanism 15 is a part for compressing the refrigerant.

  An annular outer peripheral wall 12b is erected from the peripheral edge of the outer surface of the bottom wall 12a of the second housing 12, and the open end of the cover 16 having a covered cylindrical shape is joined to the open end of the external peripheral wall 12b. Yes. A motor drive circuit 20 that controls the electric motor 13 is housed in the housing space S defined by the bottom wall 12 a, the outer peripheral wall 12 b, and the cover 16 of the second housing 12.

  The electric compressor C circulates the refrigerant through the discharge path 31 and the suction path 32 connected to the external refrigerant circuit 30. The discharge path 31 connects the compression mechanism 15 side of the electric compressor C and the external refrigerant circuit 30, and the suction path 32 connects the electric motor 13 side of the electric compressor C and the external refrigerant circuit 30.

  Next, the attachment structure of the motor drive circuit 20 to the housing H will be described. The motor drive circuit 20 includes an inverter, and specifically includes a flat board and various electronic components such as a power module (for example, IPM: intelligent power module), an electrolytic capacitor, and a coil mounted on the board. ing. Of the electronic components mounted on the substrate of the motor drive circuit 20, the power module is a member that generates heat when driven by energization, and therefore can be grasped as a heating element. On the other hand, since the housing H can exchange heat with the refrigerant passing through the housing H, it can be grasped as a heat radiating member. Therefore, in the present embodiment, the housing H (particularly, the bottom wall 12a of the second housing 12) is used as a heat radiating member, and the power module mounted on the substrate of the motor drive circuit 20 is used as a heating element.

  As shown in FIG. 2, in the accommodation space S, the substrate 21 of the motor drive circuit 20 is screwed to a support portion 12c erected on the outer surface of the bottom wall 12a of the second housing 12, and the outer surface of the bottom wall 12a. Is supported by the second housing 12 in a state of being parallel to and spaced apart from the outer surface. The power module 22 is mounted on a mounting surface located on the bottom wall 12a side of the substrate 21. Specifically, the power module 22 includes a lead frame 22 a (terminal) that is exposed and extends to the outside, and the leading end of the lead frame 22 a is soldered to the substrate 21. The power module 22 has a surface opposite to the substrate 21 bonded to the bottom wall 12a via an adhesive layer B.

  The adhesive layer B that bonds the bottom wall 12a and the power module 22 is a layer containing an epoxy resin as a resin component and a modified thermal conductive filler, specifically, an epoxy resin containing a modified thermal conductive filler. It is a layer formed by curing an adhesive. The thickness of the adhesive layer B is set in the range of 20 μm to 1 mm, for example.

  The modified thermally conductive filler is a particle obtained by bonding an organic compound to the surface of an inorganic particle. Examples of the organic compound include a hydroxyl group (including a phenolic hydroxyl group), a carboxyl group, an amino group (including 1 to 3), a formyl group, a carbonyl group, an imino group, a thiol group, an ester bond, and an amide bond. And an organic compound having at least one functional group or bonding site. The modified thermally conductive filler increases the affinity between the particle surface and the epoxy resin. Therefore, compared with inorganic particles whose surface is not modified, aggregation in the epoxy resin adhesive is suppressed, and the dispersibility in the epoxy resin adhesive is excellent. When the modified thermally conductive filler is blended in a highly dispersed state in the epoxy resin adhesive, the modified thermally conductive filler is positioned in a highly dispersed state even in the adhesive layer B formed by curing the epoxy resin adhesive. Will do. As a result, when heat is transmitted through the adhesive layer B, heat is more easily transmitted through the modified heat conductive filler portion having high thermal conductivity, and the thermal conductivity of the adhesive layer B is improved.

Next, an epoxy resin adhesive for forming the adhesive layer B will be described.
The epoxy resin adhesive contains an epoxy resin as a resin component and a modified thermally conductive filler.

  The epoxy resin as the resin component is not particularly limited as long as it is an epoxy resin generally used as an adhesive, but it is preferable to use one having a low curing temperature. Specifically, it is preferable to use an epoxy resin having a curing temperature lower than the melting point (for example, 230 to 240 ° C.) of the solder used for mounting the power module 22 on the substrate 21, and the curing temperature is normal temperature (15 to It is more preferable to use an epoxy resin that is 35 ° C.). Further, it may be a one-component curable epoxy resin or a two-component or more multi-component curable epoxy resin.

The modified thermally conductive filler is a particle obtained by bonding an organic compound to the surface of an inorganic particle. The inorganic particles used in the modified thermally conductive filler are not particularly limited as long as the particles are made of an inorganic material having thermal conductivity (for example, a material having a thermal conductivity of 10 W / mk or more). Particles made of any of materials, semiconductor materials, and conductive materials may be used. Examples of the insulating material include metal oxides such as aluminum oxide (Al ₂ O ₃ ) and magnesium oxide (MgO), and nitrides such as aluminum nitride (AlN) and boron nitride (BN). An example of the semiconductor material is silicon carbide (SiC). Examples of conductive materials include copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), iron (Fe), cobalt (Co), zinc (Zn), silver (Ag), and tin (Sn). , Platinum (Pt), and gold (Au). From the viewpoint of imparting insulation to the adhesive layer B, it is preferable to use inorganic particles made of an insulating material.

  Examples of organic compounds to be bonded to the surface of the inorganic particles include hydroxyl groups (including phenolic hydroxyl groups), carboxyl groups, amino groups (including grades 1 to 3), formyl groups, carbonyl groups, imino groups, thiol groups, esters. An organic compound having at least one functional group or bonding site selected from a bond and an amide bond, such as alcohols, aldehydes, ketones, carboxylic acids, esters, amines, thiols, amides, oximes, phosgene, Examples include enamines, amino acids, peptides, and saccharides.

  Specific examples of the organic compound include, for example, pentanol, pentanal, pentanoic acid, pentanamide, pentanethiol, hexanol, hexanal, hexanoic acid, hexanamide, hexanethiol, heptanol, heptanal, heptanoic acid, heptaneamide, heptanethiol, Octanol, octanal, octanoic acid, octatanamide, octanethiol, decanol, decanal, decanoic acid, decanamide, decanethiol, 2-ethylhexanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, linol Examples include acids, linolenic acid, oxalic acid, malonic acid, and succinic acid. In addition, only one type of the organic compound may be bonded to the surface of the inorganic particles, or two or more types may be bonded.

  Among these organic compounds, an organic compound having two or more of the above functional groups or binding sites in one molecule is preferable from the viewpoint of improving the affinity for the epoxy resin. In addition, an organic compound having a hydroxyl group, an amino group, and a carboxyl group is preferable from the viewpoint of improving the affinity for the epoxy resin, particularly the affinity for the epoxy group. Therefore, as the organic compound, dicarboxylic acids such as oxalic acid, malonic acid, and succinic acid are particularly preferable.

  As a method for bonding the organic compound to the surface of the inorganic particles, a known method (for example, a supercritical hydrothermal synthesis reaction disclosed in JP-A-2005-194148) can be used. And as a coupling | bonding mode of the surface of the said inorganic particle, and the said organic compound, the coupling | bonding which forms a salt may be sufficient, and the coupling | bonding through an ether bond, an ester bond, an N atom, an S atom, And a bond via a C atom.

  The particle diameter of the modified inorganic particles is not particularly limited, but a finer particle diameter is preferable from the viewpoint of easily increasing the filling amount (volume fraction) of the modified inorganic particles in the epoxy resin adhesive. Specifically, the particle size of the modified thermally conductive filler is preferably 120 μm or less, more preferably 60 μm or less, and even more preferably 30 μm or less. In order to efficiently increase the filling amount (volume fraction) of the modified thermal conductive filler, the modified thermal conductive filler (main particle) having a relatively large particle size and the modified thermal conductive filler having a relatively small particle size. (Sub-particles) are preferably used in combination. Specifically, a combination of a modified thermally conductive filler (primary particle) having a particle size of 20 to 120 μm and a modified thermally conductive filler (subparticle) having a particle size of 0.14 to 16 μm is preferable, and the particle size is 10 A combination of a modified thermal conductive filler (primary particles) of ˜60 μm and a modified thermal conductive filler (subparticles) having a particle size of 0.8-8 μm is more preferred.

  In the modified thermal conductive filler, since the size of the organic compound bonded to the surface of the inorganic particles is very small relative to the size of the inorganic particles, the particle size of the modified thermal conductive filler is not changed. It can be regarded as the particle size of the particles. In addition, “particle size” in the present specification means an average particle size observed with a scanning electron microscope (SEM).

  The volume fraction of the modified thermally conductive filler in the epoxy resin adhesive is not particularly limited, but is preferably set in the range of 30 to 90% by volume, and set in the range of 40 to 75% by volume. Is more preferable. As described above, the modified thermally conductive filler is excellent in dispersibility in the epoxy resin. Therefore, a high volume fraction (high blending ratio) of 30 to 90% by volume can be realized.

  When the volume fraction of the modified thermally conductive filler is in the range of 30 to 90% by volume, the handling property (handling property) of the epoxy resin adhesive is improved and the epoxy resin adhesive is cured. The thermal conductivity of the layer B can be suitably ensured. Furthermore, when the volume fraction of the modified thermally conductive filler is in the range of 30 to 90% by volume, an appropriate viscosity is imparted to the epoxy resin adhesive. Thereby, when attaching the motor drive circuit 20 to the bottom wall 12a of the second housing 12, it becomes possible to allow the epoxy resin adhesive to absorb tolerances such as assembly tolerances and manufacturing tolerances generated in each member.

  The volume fraction of the modified thermally conductive filler in the epoxy resin adhesive can be regarded as the volume fraction of the modified thermally conductive filler in the adhesive layer B formed by curing the epoxy resin adhesive as it is. That is, the volume fraction of the modified thermally conductive filler in the adhesive layer B is also preferably in the range of 30 to 90% by volume, and more preferably in the range of 40 to 75% by volume.

  In addition, the epoxy resin adhesive may contain only one type of modified thermal conductive filler, the inorganic particles constituting the modified thermal conductive filler, and the organic compound bonded to the inorganic particles. Plural types of modified thermally conductive fillers, one or both of which may be different, may be contained. Further, in the epoxy resin adhesive, resin components other than the epoxy resin and additives other than the modified heat conductive filler (for example, a general heat agent) are used within a range that does not impair the adhesiveness and thermal conductivity of the adhesive layer B. A conductive filler (inorganic particles whose surface is not modified), an antifoaming agent, a solvent, and the like) may be contained.

Next, a method for attaching the motor drive circuit 20 to the bottom wall 12a of the second housing 12 will be described.
First, an epoxy resin adhesive is applied to a predetermined position on the outer surface of the bottom wall 12 a of the second housing 12. Next, the substrate 21 on which electronic components such as the power module 22 are mounted is positioned on the bottom wall 12a. Then, the bottom wall 12a and the power module 22 are brought into close contact with each other through the epoxy resin adhesive, and the support portion 12c erected on the bottom wall 12a of the second housing 12 and the substrate 21 are brought into contact with each other. At this time, the epoxy resin adhesive applied to the bottom wall 12a is crushed by the power module 22, and the bottom wall 12a and the power module 22 are brought into close contact with each other. By this operation, tolerances such as assembly tolerances and manufacturing tolerances generated on the second housing 12 side or the motor drive circuit 20 side are absorbed by the epoxy resin adhesive (later adhesive layer B).

  And after fixing the board | substrate 21 with screwing with respect to the support part 12c of the 2nd housing 12, an epoxy resin adhesive is heated using heaters, such as a heater, according to the curing temperature of an epoxy resin adhesive, The adhesive layer B is formed by curing. The heating temperature for curing the epoxy resin adhesive is set to a temperature lower than the melting point of the solder used for mounting various electronic components on the substrate 21 and a temperature that does not damage the electronic components. As described above, the motor drive circuit 20 is attached to the bottom wall 12 a of the second housing 12.

Next, the operation in this embodiment will be described.
The power module 22 mounted on the substrate 21 of the motor drive circuit 20 generates heat when driven by energization. The heat of the power module 22 is transferred to the bottom wall 12a of the housing H through the adhesive layer B. The heat transmitted to the bottom wall 12a is radiated by heat exchange with the refrigerant passing through the housing H. In particular, the modified thermally conductive filler is present in a highly dispersed state in the adhesive layer B. Therefore, when heat is transferred from the power module 22 side to the bottom wall 12a side in the adhesive layer B, the heat is easily transferred through more of the modified heat conductive filler portion having high heat conductivity. Thereby, heat is efficiently transmitted in the adhesive layer B, and heat conduction from the power module 22 to the bottom wall 12a is promoted.

Next, the effect in this embodiment will be described below.
(1) In the present embodiment, the bottom wall 12a is interposed via the adhesive layer B without interposing a member such as a heat spreader between the bottom wall 12a of the housing H as the heat radiating member and the power module 22 as the heat generating element. And the power module 22 are directly bonded.

  Thereby, it is possible to design the accommodation space S which is an installation space for accommodating the motor drive circuit 20 to be smaller. Therefore, it is easy to reduce the installation space as compared with the heat dissipation structure of the heat generating element using the heat spreader. As a result, it becomes easy to reduce the size of the entire electric compressor C.

  Further, by directly bonding the bottom wall 12a and the power module 22 via the adhesive layer B, the heat spreader and the screw for fixing the heat spreader to the bottom wall and the power module can be omitted, and the number of parts can be reduced. be able to. Furthermore, manufacturing efficiency can be improved by omitting the step of screwing the heat spreader during manufacturing.

  (2) As the adhesive layer B, an adhesive layer containing a modified thermally conductive filler in which an organic compound is bonded to the surface of inorganic particles and an epoxy resin is used. The modified thermally conductive filler has a higher affinity with the epoxy group of the epoxy resin than the inorganic particles whose surface is not modified. Therefore, in the adhesive layer B, the thermal resistance when heat is transferred from the modified thermal conductive filler to the epoxy resin, or from the epoxy resin to the modified thermal conductive filler is reduced, and between the modified thermal conductive filler and the epoxy resin. Heat conduction efficiency is improved. Thereby, the thermal conductivity of the adhesive layer B as a whole is improved.

  Therefore, the heat of the power module 22 can be more efficiently transferred to the bottom wall 12a by bonding the bottom wall 12a and the power module 22 via the adhesive layer B containing the modified thermally conductive filler and the epoxy resin. it can. The heat transmitted to the bottom wall 12a is radiated by heat exchange with the refrigerant passing through the housing H. Therefore, it is possible to effectively dissipate the heat of the power module 22 without using a heat spreader.

  (3) As the adhesive layer B, a layer formed by curing an epoxy resin adhesive containing a modified thermally conductive filler is used. The modified thermally conductive filler is excellent in dispersibility in the epoxy resin adhesive because aggregation in the epoxy resin adhesive is suppressed. When the modified thermally conductive filler is blended in the epoxy resin adhesive in a highly dispersed state, the modified thermally conductive filler is positioned in the highly dispersed state even in the adhesive layer B formed by curing the epoxy resin adhesive. Thus, the thermal conductivity of the adhesive layer B is improved.

  (4) The support portion 12c is provided on the bottom wall 12a of the housing H, and the substrate 21 on which the power module 22 is mounted is fixed to the support portion 12c. By fixing the substrate 21 to the bottom wall 12a, the fixed state of the power module 22 with respect to the bottom wall 12a can be further stabilized.

  (5) Insulating properties can be imparted to the adhesive layer B by making the inorganic particles constituting the modified thermally conductive filler particles made of an insulating material. As shown in FIG. 2, when the power module 22 having a shape in which the lead frame 22a is exposed to the outside and the bottom wall 12a of the conductive (aluminum) housing H are targeted, the adhesive layer B is insulative. As a result, the discharge from the lead frame 22a to the bottom wall 12a side can be suppressed.

  (6) By setting the volume fraction of the modified thermally conductive filler in the adhesive layer B to 30 to 90% by volume, the thermal conductivity of the adhesive layer B can be suitably ensured. And the heat dissipation efficiency from the power module 22 can be improved more.

In addition, this embodiment can also be changed and embodied as follows.
In the above embodiment, among the various electronic components mounted on the substrate 21 of the motor drive circuit 20, the power module 22 is used as a heating element. However, any heating element that requires cooling should be used as a heating element. Can do. For example, power elements and capacitors that are not modularized, such as IGBTs and MOSFETs, may be used as the heating elements.

  In the case where the power module 22 having the shape in which the lead frame 22a is exposed to the outside and the bottom wall 12a of the conductive (aluminum) housing H are targeted, it is preferable to provide insulation to the adhesive layer B. However, it is not always necessary to provide insulation to the adhesive layer B.

  In the above embodiment, the power module 22 having the shape in which the lead frame 22a is exposed to the outside is used. However, a leadless type power module 22 in which the terminal is not exposed to the outside may be used. In this case, since it is difficult for electric discharge from the lead frame 22a to the bottom wall 12a side, there is no need to consider the conductivity of the adhesive layer B in particular.

  -Although the screwing direction of the screw stopper which fixes the support part 12c of the bottom wall 12a and the board | substrate 21 is not specifically limited, as shown in FIG. 2, the bottom wall 12a and power module through the adhesive layer B are shown. The overlapping direction with 22 is preferably the same direction. When the screwing direction of the screw fixing for fixing the support portion 12c of the bottom wall 12a and the substrate 21 and the overlapping direction of the bottom wall 12a and the power module 22 via the adhesive layer B are the same, the screw fixing The problem that distortion (displacement) occurs in the adhesive layer B due to the screwing force at the time can be suppressed.

  -The structure for fixing the support part 12c of the bottom wall 12a and the board | substrate 21 is not limited to a screw stop, It can fix similarly using a well-known fixing member. Moreover, you may abbreviate | omit the screwing (fixing structure) between the support part 12c and the board | substrate 21. FIG.

  -The support part 12c may be omitted. In this case, in order to secure a distance between the outer surface of the bottom wall 12a and the substrate 21, the substrate 21 and the bottom wall 12a may be screwed together with a spacer or the like interposed therebetween.

  -When the power module 22 is fixed to the bottom wall 12a of the housing H, in addition to the adhesion by the adhesive layer B, a fixing structure by a fixing member such as a screw stopper may be formed.

  -The configuration of the housing H, such as the shape and the divided configuration, is not particularly limited. For example, the cover 16 may also have a configuration of the housing H. Further, the outer peripheral wall 12b of the second housing 12 may be omitted, and the open end of the cover 16 may be directly joined to the outer surface of the bottom wall 12a. In the case of providing the outer peripheral wall 12b, from the viewpoint of workability at the time of fixing the substrate, it is preferable to make the protruding length from the outer surface of the bottom wall 12a smaller than the support portion 12c, as shown in FIG.

  In the above embodiment, the motor drive circuit 20 is disposed on the outer surface side of the bottom wall 12a of the housing H. However, the motor drive circuit 20 may be disposed on the outer surface side of the peripheral wall portion of the housing H. In this case, the peripheral wall portion of the housing H is used as a heat dissipation member, and the power module 22 is bonded to the peripheral wall portion via the adhesive layer B.

  The heat dissipating structure (attachment structure) employed in the electric compressor C of the present invention is not limited to the electric compressor C, and a heat dissipating member such as a heat sink and a heat sink provided to dissipate the heat of the heat generating element. It is applicable if it is an electronic device provided with.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
(A) an electric compressor comprising a compression mechanism, a drive motor that drives the compression mechanism, a housing that houses the compression mechanism and the drive motor, and a motor drive circuit that controls the drive motor, The heater element provided in the motor drive circuit and the wall portion of the housing are bonded via an adhesive layer, and the adhesive layer includes a modified thermally conductive filler in which an organic compound is bonded to the surface of inorganic particles, and an epoxy. An electric compressor comprising a resin.

  (B) A heat conductive adhesive comprising an epoxy resin as a resin component and a modified heat conductive filler in which an organic compound is bonded to the surface of inorganic particles.

B ... Adhesive layer, C ... Electric compressor, H ... Housing, S ... Housing space, 11 ... First housing, 12 ... Second housing, 12a ... Bottom wall, 12b ... External peripheral wall, 12c ... Supporting part, 13 ... Compression Mechanism: 14 ... Rotating shaft 15 ... Electric motor 16 ... Cover 20 ... Motor drive circuit 21 ... Substrate 22 ... Power module 22a ... Lead frame 30 ... External refrigerant circuit 31 ... Discharge path 32 ... Suction Route.

Claims (8)

A heating element;
A heat dissipating member attached to the heating element;
An adhesive layer that bonds the heat generating element and the heat dissipation member;
The said adhesive layer contains the modified heat conductive filler which combined the organic compound on the surface of the inorganic particle, and an epoxy resin, The electronic device characterized by the above-mentioned.   The organic compound has at least one functional group or bonding site selected from a hydroxyl group, a carboxyl group, an amino group, a formyl group, a carbonyl group, an imino group, a thiol group, an ester bond, and an amide bond. 1. The electronic device according to 1.   The electronic device according to claim 2, wherein the organic compound has at least one functional group selected from a hydroxyl group, a carboxyl group, and an amino group.   The electronic device according to claim 2, wherein the modified thermal conductive filler is a particle obtained by bonding the inorganic particles and the organic compound by a supercritical hydrothermal synthesis reaction.   The electronic device according to any one of claims 2 to 4, wherein the inorganic particles are made of an insulating material.   The electronic device according to claim 1, wherein a volume fraction of the modified thermally conductive filler in the adhesive layer is 30 to 90% by volume.   The electronic device according to claim 1, wherein a substrate on which the heating element is mounted is fixed to the heat dissipation member.   The electronic device according to claim 1, wherein the heat generating element is used in a motor drive circuit of an electric compressor, and the heat radiating member is a housing of the electric compressor.

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