JP7208105B2 - Resin molded product - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin molded article, and more particularly, it constitutes at least a part of an assembly having an electrical component that is a heat source and a heat receiving body that receives the heat generated by the electrical component, and is interposed between the electrical component and the heat receiving body. The present invention relates to a resin molded product that is arranged as a

A vehicle such as an electric vehicle (EV) or a hybrid vehicle (HV) is equipped with several assemblies having electrical components that are heat sources and heat receivers that receive the heat generated by the electrical components. As a specific example, electronic devices such as PCU (power control unit) and ECU (electronic control unit) are housed in a dedicated case to form a case assembly, which is installed in the engine room or room. It is well known in the art. Such a case assembly is configured by partially using an insulating resin molded product, and the electronic device and a metal member (for example, a heat sink, etc.) as a heat receiving body are connected via the resin molded product. ing.

In general, a resin molded product that constitutes this type of case assembly has a base portion made of a thermoplastic resin, and a bus bar made of a conductive metal material is inserted into the base portion, for example. Provided by molding. The electronic device is mounted on the resin-molded product by connecting the terminals of the electrical parts constituting the electronic device to the bus bar.

By the way, conventionally, when an electric component of an electronic device or the like generates heat due to energization, the bus bar connected thereto is also indirectly heated, and the temperature rises. Therefore, unless the heat of the electrical components and busbars is dissipated quickly to the outside of the case assembly, the temperature inside the case assembly cannot be prevented from rising, and the electrical components cannot be protected from the heat. In addition, since the thermal load on the busbars and resin moldings increases, it is necessary to increase the thickness and size of the busbars and resin moldings in order to cope with this, which hinders the reduction of the overall size and weight of the equipment. turn into.

Therefore, as a case assembly as described above, there has been conventionally proposed a case assembly in which a heat transfer film or the like having insulation and thermal conductivity is sandwiched between a resin molded product and a heat sink (see, for example, Patent Document 1). ). According to this configuration, the heat of the electric parts and the busbar is conducted to the heat sink through the resin molding and the heat transfer film, and is dissipated from the heat sink to the outside of the case assembly, thereby cooling the electric parts and the busbar. It has become.

JP 2005-019434 A

However, in the case of such a case assembly, although a heat transfer film having thermal conductivity and the like is used, the adhesion between the heat transfer film and the resin molded product, the adhesion between the heat transfer film and the heat sink, and the adhesion between the heat transfer film and the heat sink. sex wasn't enough. Therefore, there is a drawback that heat from the resin molded product cannot be efficiently conducted to the heat sink. Moreover, since the heat transfer film is mainly composed of a synthetic resin material, it also has a drawback that the heat conductivity of the heat transfer film itself is low. For the reasons described above, it has been impossible to cool the case assembly efficiently in the conventional art.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a resin molded product that can be assembled into an assembly and that can improve the cooling efficiency of the assembly.

In order to solve the above problems, the invention described in Means 1 constitutes at least a part of an assembly having an electrical component as a heat source and a heat receiver that receives heat generated by the electrical component, and the electrical component and A resin molded product interposed between the heat-receiving body and a base portion formed of a thermoplastic resin and having a wall portion, and a material having a thermal conductivity higher than that of the thermoplastic resin. A busbar holding portion capable of holding a busbar having a connecting portion for connecting the electric component is formed on the wall portion, and the wall portion is an attachment side of the electric component. It has a first main surface and a second main surface opposite to the first main surface and on the mounting side of the heat receiving body, and at least a part of the first main surface of the wall portion has the The thermoplastic resin forming the base portion is exposed, and the layered portion is formed in at least part of a position facing the heat receiving body on the second main surface of the wall portion, and the layered portion The gist of the present invention is a resin molded product characterized in that a portion is formed over an area larger than the outer dimensions of the electrical component in a plan view.

Therefore, according to the invention described in Means 1, since the thermoplastic resin is exposed on the first main surface on which the electric parts are attached, the heat of the base portion is released to the outside by thermal radiation. On the other hand, a layered portion is formed on the second main surface on which the heat receiving member is attached, and the heat receiving member is arranged to face the layered portion via the layered portion. Moreover, the layered portion is formed over an area larger than the external dimensions of the electrical component in a plan view. For this reason, heat is efficiently conducted to the heat receiving body via the layered portion while diffusing heat in the planar direction of the second main surface by the layered portion, whereby the heat of the base portion is released to the outside. Therefore, the cooling efficiency of the assembly can be improved.
The gist of the invention described in means 2 is that in means 1, the smoothness of the surface of the layered portion is higher than the smoothness of the surface of the second main surface.
Therefore, according to the invention described in Means 2, since the adhesion between the base portion and the heat receiving member is improved, heat can be efficiently conducted to the heat receiving member through the layered portion.

The gist of the invention described in means 3 is that in means 1 or 2, the resin molded product is an insert molded product having a structure in which the bus bar is held in the bus bar holding portion of the base portion.

Therefore, according to the third aspect of the invention, since the busbar is held in close contact with the base without any gap, the busbar, which is directly affected by the heat generated by the electrical component as a heat source, transfers heat to the base. can be moved efficiently. Therefore, this contributes not only to the improvement of cooling efficiency, but also to the overall miniaturization and weight reduction.

The invention according to means 4 is characterized in that, in any one of means 1 to 3, the layered portion is a metal sputtering layer.

Therefore, according to the invention described in means 4, since the metal sputtering layer has excellent adhesion of the layered portion to the base portion, heat can be efficiently transferred to the heat receiving body via the layered portion.

As described in detail above, according to the first to fourth aspects of the invention, it is possible to provide a resin molded product that can be attached to an assembly and that can improve the cooling efficiency of the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic which shows the resin molding of embodiment which materialized this invention. (a) is an enlarged cross-sectional view of a main part showing the appearance of the interface between the second main surface of the wall portion and the layered portion in the resin molded product of the embodiment, and (b) shows the appearance of the second main surface before the formation of the layered portion; FIG. 2 is an enlarged cross-sectional view of a main part shown; Schematic for demonstrating the method of a heat dissipation evaluation test in the Example which materialized embodiment. 5 is a graph showing the relationship between time and heat source temperature when the formation position of the layered portion is changed in the heat dissipation evaluation test of the example. 4 is a graph showing the relationship between time and heat source temperature when the thickness of the layered portion and the thermal conductivity of the thermoplastic resin are changed in the heat dissipation evaluation test of the example. 5 is a graph showing the relationship between the thickness of the layered portion and the surface roughness of the second main surface in the surface roughness change investigation test of the example. Schematic which shows the resin molding of another embodiment which actualized this invention.

BEST MODE FOR CARRYING OUT THE INVENTION A resin molded product of one embodiment embodying the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.

FIG. 1 is a schematic diagram of a resin molded product 1 of this embodiment. As shown in FIG. 1, this resin molded product 1 is a member constituting at least a part of a case assembly 4 having an electrical component 2 as a heat source and a heat receiving member 3 for receiving heat generated by the electrical component 2. be. This resin molded product 1 is used while being interposed between the electrical component 2 and the heat receiving body 3 . Specifically, the case assembly 4 in this embodiment is a case assembly 4 for mounting in a vehicle, which is arranged in an engine room. The resin molded product 1 is an electrical component casing for heat dissipation of electrical components 2 such as transistors such as FETs and IGBTs, diodes, resistors, capacitors, coils, and transformers. The heat receiving body 3 is a member made of a material having a lower temperature and higher thermal conductivity than the electric component 2 which is a heat source, and is an aluminum die-cast PCU case that also functions as a heat sink. The heat receiving body 3 and the resin molded product 1 can be joined to each other by an arbitrary method, and are joined to each other using, for example, fastening means such as bolts.

This resin molded product 1 is composed of a base portion 11, a layered portion 12, a busbar 13, a busbar holding portion 14, and the like.

The base portion 11 constituting the resin molded product 1 is a member having, for example, a wall portion 15 having a relatively large area. The wall portion 15 has a first main surface 15a (upper surface in FIG. 1) on which the electrical component 2 is attached, and a second main surface on the opposite side of the first main surface 15a and on which the heat receiving body 3 is attached. 15b (lower surface in FIG. 1). Although the shape of the wall portion 15 is not particularly limited, it is preferably a plate-like portion, and more preferably a plate-like portion having an area substantially equal to the outer dimensions of the base portion 11 in plan view. This is because the wall portion 15 having such a shape is suitable not only as a place for mounting the electrical component 2 but also as a place for forming the layered portion 12 . Note that the wall portion 15 may not necessarily be flat, and may be curved or have steps, for example.

The thickness of the wall portion 15 is arbitrary and not particularly limited, but is preferably, for example, 1 mm or more and 4 mm or less. It can be obtained by molding. If the thickness is less than 1 mm, the desired insulation and mechanical strength may not be ensured. On the other hand, when it exceeds 4 mm, there is a possibility that sink marks are likely to occur during molding. The size of the wall portion 15 is arbitrary, and can be appropriately determined according to the size and number of the electrical components 2 to be mounted.

As a material for forming the base portion 11, synthetic resin having light weight and insulating properties is selected in view of the fact that it is used as a part of the case assembly 4 for mounting on the vehicle. As a molding method for obtaining the base portion 11, various conventionally known methods can be adopted. Specifically, for example, not only methods using molds such as press molding and injection molding, but also methods not using molds (cutting, 3D printing, etc.) are allowed. Here, an injection-molded article made of a thermoplastic resin can be mentioned as a preferable base portion 11 . This is because an injection-molded article made of a thermoplastic resin is excellent in moldability, cost efficiency, light weight, processability, insulating properties, and the like. Specific examples of thermoplastic resins include PPS resins, PBT resins, PA resins, PP resins, PPE resins, ABS resins, etc. Among these, it is preferable to select PPS resins. This is because the PPS resin is a general-purpose resin, has excellent heat resistance, and has a relatively small coefficient of linear expansion. In addition, the PPS resin is compatible with many metal materials such as aluminum, so that the adhesiveness of the layered portion 12 can be improved. Here, it is preferable to select an injection-molded product made of a material containing inorganic particles and inorganic fibers in a matrix of PPS resin as the base portion 11, and this provides high shape stability and adhesion of the layered portion 12. becomes easier to obtain.

Further, it is preferable that the thermoplastic resin forming the base portion 11 has a higher thermal conductivity. For example, a resin with a thermal conductivity of 0.3 W/(mK) or more can be suitably used, preferably 0.5 W/(mK) or more, and further a high thermal conductivity resin of 1 W/(mK) or more. is more preferable. The reason for this is that when a resin having such properties is used, heat is diffused in the plane direction of the second main surface 15 b by the layered portion 12 while heat is transferred from the base portion 11 through the layered portion 12 to the heat receiving body 3 . This is because it is possible to efficiently conduct

The bus bar 13 that constitutes the resin molded product 1 is a conductor portion that mainly connects the power supply and the electrical component 2, and is formed by punching out a conductive plate material by pressing. As the conductive plate material forming the bus bar 13, a plate material made of at least one metal selected from copper, copper alloys (such as brass), aluminum, and the like is used. The busbar 13 is installed on the base portion 11 with at least a portion thereof held by a busbar holding portion 14 formed on the wall portion 15 . In this case, a molded product having a structure in which the base portion 11 having the groove-shaped or hole-shaped busbar holding portion 14 is prepared in advance and the separately manufactured busbar 13 is attached to the substrate portion 11 may be used. There may be. That is, by performing injection molding of the base portion 11 with the busbars 13 arranged in a mold, a structure in which the busbars 13 are held in close contact at predetermined positions (busbar holding portions 14) in the base portion 11 may be employed. good.

The busbar 13 has a connecting portion 13a at a portion exposed on the side of the first main surface 15a on which the electrical component 2 is attached. As a result of connecting the terminal 2a of the electrical component 2 to the connecting portion 13a, the electrical component 2 and the bus bar 13 are electrically connected. The plan view shape of the bus bar 13 is not particularly limited, and may be any shape depending on the application. The terminals 2a and the busbars 13 are connected by fastening means such as bolts, soldering, wire bonding, or the like. Moreover, the bus bar 13 may be formed in a flat plate shape, but may be formed by bending in the thickness direction.

The layered portion 12 that constitutes the resin molded product 1 is formed on the outer surface of the wall portion 15 . More specifically, the layered portion 12 is formed on at least a portion of the second main surface 15 b of the wall portion 15 at a position facing the heat receiving body 3 . In other words, the layered portion 12 may be formed so as to cover a portion of the second main surface 15b of the wall portion 15, or may be formed so as to cover the entirety. In addition, the layered portion 12 is formed on the second main surface 15b of the wall portion 15 over an area larger than the outer dimensions of the electrical component 2, which is the heat source, in a plan view. However, the layered portion 12 is not formed on the first main surface 15a of the wall portion 15, and the thermoplastic resin forming the base portion 11 is exposed on at least a portion of the first main surface 15a. The reason is that the heat received by the base portion 11 is efficiently released to the outside by thermal radiation from the first main surface 15a side. Conversely, a portion of the first main surface 15a may be covered with the layered portion 12 or the like as long as the heat radiation is not hindered.

The layered portion 12 is made of a material having higher thermal conductivity than the thermoplastic resin forming the base portion 11 . With such a material, the layered portion 12 diffuses heat in the planar direction of the second main surface 15b, while efficiently conducting heat from the base portion 11 side to the heat receiving body 3 side through the layered portion 12. This is because As the layered portion 12, a layer made of an inorganic material (for example, a metal layer, a carbon layer, a ceramic layer, etc.) can be selected, and it is particularly preferable to select a metal layer. This is because many metal materials have higher thermal conductivity than synthetic resin materials, and the degree of freedom in material selection is large. Specific examples of such metal layers include metal layers made of gold, silver, copper, platinum, iron, aluminum, titanium, nickel, cobalt, chromium, tin, lead, etc., and alloys containing these metals as components. Layers (eg, stainless alloy layers, solder alloy layers, etc.) can be mentioned. Among these, an aluminum layer is particularly suitable. This is because aluminum has a high thermal conductivity, which is advantageous for heat radiation, and is an inexpensive metal material, which contributes to cost reduction, and is relatively lightweight, which contributes to overall weight reduction. Examples of ceramic layers include an alumina layer, an aluminum nitride layer, a silicon nitride layer, a boron nitride layer, a silicon carbide layer, and a mullite layer.

A metal layer typified by aluminum is formed, for example, on the surface 11a of the base portion 11 by a conventionally known film forming method, specifically plating, chemical vapor deposition (CVD), sputtering, vacuum deposition, ion plating, or the like. formed by a variety of techniques such as physical vapor deposition (PVD). In addition, a method of applying a liquid material containing metal by a roll coating method, a spray coating method, a curtain coating method, a method of printing the liquid material, and a film made of a material having high thermal conductivity when forming the base portion 11. can be integrated with the surface 11a. According to these methods, a thin, uniform layer that is in close contact with the base portion 11 can be formed relatively easily. The metal layer is preferably formed by a physical film-forming method such as sputtering among the above-mentioned methods. This is because a metal thin film (sputtering layer) formed by a sputtering method or the like has excellent adhesion to the base portion 11 even if it is thin. In addition, since the sputtered layer does not produce burrs, there is also the advantage that there is no risk of contamination by foreign matter.

The thickness of the metal layer (for example, an aluminum layer) as the layered portion 12 is not limited and is arbitrary. It is formed thinner than the wall portion 15) with a thickness of 1 mm to 4 mm. This is because if the metal layer is thicker than the base portion 11, the proportion of the metal material used relative to the synthetic resin material increases, making it difficult to reduce the cost and weight of the resin molded product 1 as a whole.

The thickness of the metal layer (for example, a sputtering layer of aluminum) is preferably 0.2 μm or more and 2.0 μm or less, more preferably 0.3 μm or more and 1.3 μm or less, and particularly 0.5 μm or more. It is preferably 1.0 μm or less. The reason for this is that the metal layer itself can be extremely thin in spite of the fact that good thermal conductivity is imparted, so that cost reduction and weight reduction can be effectively achieved. Here, if the thickness exceeds 2.0 μm, it may become difficult to effectively reduce the cost and weight. Conversely, if the thickness is less than 0.1 μm, it may be difficult to impart the desired thermal conductivity, or the layered portion 12 may be easily peeled off to expose the base portion 11 . Moreover, it is also because the layered portion 12 may not be able to sufficiently fill the minute unevenness of the second main surface 15b.

When the layered portion 12 is an aluminum layer, it is preferable to configure the resin molded product 1 by combining it with the base portion 11 made of an injection molded product made of PPS resin. This is because, as described above, the PPS resin has good compatibility with aluminum, so that the adhesion of the layered portion 12 to the base portion 11 can be improved.

FIG. 2(a) is an enlarged cross-sectional view showing the state of the interface between the second main surface 15b of the wall portion 15 and the layered portion 12, and FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing a state of a main surface 15b; As shown in FIG. 2(b), the smoothness of the second main surface 15b of the wall portion 15 basically depends on the smoothness of the molding surface of the mold. For example, Rz (maximum height roughness) is 1.00 μm or more, and Ra (arithmetic mean roughness) is 0.18 μm or more. On the other hand, in FIG. 2A, in which the layered portion 12 is formed on the second main surface 15b, the minute unevenness of the second main surface 15b is filled with the layered portion 12, so that the surface 12a of the layered portion 12 is The smoothness is higher than the smoothness of the surface of the second main surface 15b. In other words, the surface roughness of the layered portion 12 is smaller than the surface roughness of the second main surface 15b. With such a configuration, not only is the state of close contact with the heat receiving body 3 improved by reducing the unevenness of the surface 12 a of the layered portion 12 , but also the unevenness of the second main surface 15 b is filled with the layered portion 12 . The adhesion state between the layered portion 12 and the wall portion 15 is also improved. Therefore, the heat on the side of the base portion 11 can be efficiently transmitted to the side of the heat receiving body 3 . The surface roughness (Rz, Ra) of the layered portion 12 is preferably 40% or more smaller than the surface roughness (Rz, Ra) of the second main surface 15b.

Examples that embody the present embodiment more concretely will be introduced below, but the present invention is not limited to the examples.

[Example 1] Heat dissipation evaluation test 1

Here, as a heat dissipation evaluation test, a study was conducted on the difference in heat dissipation when the formation position of the layered portion 12 on the base portion 11 was changed.

FIG. 3 is a schematic diagram for explaining a test apparatus used for the heat dissipation evaluation test. This test apparatus has a rectangular flat resin plate sample S1 (length 120 mm x width 60 mm x thickness 2 mm) as a base portion 11, and the upper surface (first main surface 15a) which is the surface on the heat source side. A heat source H1 corresponding to an electrical component is placed in the central portion. Specifically, an iron block (length 48 mm, width 28 mm, thickness 9 mm) with a built-in heater is used as the heat source H1. A heat source temperature measuring means T1 having a thermocouple t1 is provided to measure the temperature of the heat source H1. On the other hand, a heat sink HS1 (length 90 mm, width 70 mm, thickness 25 mm) cooled by flowing water is arranged as a heat receiving body on the lower surface (second main surface 15b) of the resin plate sample S1, which is the surface on the cooling side. ing. Then, using such a test apparatus, the temperature of the heat source H1 is changed over time by setting the heater output to a constant value (80 W) and constantly raising the temperature for a predetermined time while performing cooling by constantly passing water. It was measured. The graph in FIG. 4 shows the relationship between time and heat source temperature.

In this heat dissipation evaluation test, an aluminum layer as the layered portion 12 was formed by sputtering on either the upper surface, the lower surface, or both surfaces of the resin plate sample S1 made of commercially available PPS resin.

In FIG. 4, "PPS-GF50-1" means that aluminum sputtering layers ( That is, it means that the resin plate sample S1 is not formed with the layered portion 12).

"PPS-GF50-1+sputtering 0.2μ one side: heat source side" is a resin in which a 0.2μm aluminum sputtering layer (that is, the layered portion 12) is formed only on the first main surface 15a side of the base portion 11. This means that it is the board sample S1.

"PPS-GF50-1+sputtering 0.2μ one side: cooling side" is a resin in which a 0.2μm aluminum sputtering layer (that is, the layered portion 12) is formed only on the second main surface 15b side of the base portion 11. This means that it is the plate sample S1.

“PPS-GF50-1+sputtered 0.2 μm on both sides” means that a 0.2 μm aluminum sputtered layer (that is, the layered portion 12) is formed on both the first main surface 15a and the second main surface 15b side of the base portion 11. It means that it is the formed resin plate sample S1.

The graph in FIG. 4 shows the results when using these. The heat source temperature of each resin plate sample S1 was about 10° C. at the start of the test. When starting from this temperature and heating for 20 minutes each, the temperature reached 120 ° C. or more, but compared with "PPS-GF50-1" which does not have an aluminum sputtering layer, "PPS-GF50- The heat source temperature was slightly higher in "1+sputtering 0.2μ one side: heat source side" and "PPS-GF50-1+sputtering 0.2μ both sides". Therefore, in these resin plate samples S1, it was found that the forming position of the aluminum sputtering layer was not appropriate, which rather led to a decrease in heat dissipation. On the other hand, “PPS-GF50-1+sputtered 0.2 μm on one side: cooling side” had a slightly lower heat source temperature than “PPS-GF50-1” having no aluminum sputtered layer. Therefore, it was expected that forming the aluminum sputtering layer only on the second main surface 15b side and leaving the resin material exposed without forming it on the first main surface 15a side would lead to an improvement in heat dissipation. .

The above results were considered as follows. That is, heat radiation from the heated heat source H1 is performed through the base portion 11 in two ways. The first heat radiation route is a route for radiating heat from the first main surface 15a of the base portion 11 to the air (outside air), and the second heat radiation route is from the second main surface 15b of the base portion 11 to the heat sink HS1. It is the route of heat conduction. The thermal emissivity of the resin molded product 1 contributes to the former, and the thermal conductivity of the resin molded product 1 contributes to the latter. Based on the above, it is effective to increase both the thermal emissivity and the thermal conductivity in order to increase the heat radiation efficiency. Here, it is known that resins generally have a higher thermal emissivity than metals, while metals generally have a higher thermal conductivity than resins. Therefore, by forming an aluminum sputtering layer only on the second main surface 15b side of the base portion 11 like "PPS-GF50-1+sputtering 0.2 μ one side: cooling side", the heat on the second main surface 15b side is reduced. It was considered possible to increase the thermal emissivity of the first major surface 15a side while promoting the diffusion of heat by increasing the conductivity. On the other hand, if an aluminum sputtering layer is formed as in "PPS-GF50-1 + 0.2μ sputter one side: heat source side" or "PPS-GF50-1 + 0.2μ sputter both sides", the heat source H1 side (air side) becomes a metal surface with a low thermal emissivity, it was thought that thermal radiation from the heat source H1 side is reduced.

[Example 2] Heat dissipation evaluation test 2

In this heat dissipation evaluation test 2, the difference in heat dissipation when changing the thickness of the layered portion 12 in the base portion 11 and the thermal conductivity of the thermoplastic resin was investigated. As the test apparatus, the same one as in the above-described heat radiation evaluation test 1 was used, and the temperature of the heat source H1 was measured over time by the same method. The graph in FIG. 5 shows the relationship between time and heat source temperature.

In FIG. 5, "aluminum" means a plate sample in which a plate material made of aluminum is used as the base portion 11, and the aluminum sputtering layer (that is, the layered portion 12) is not formed on either surface thereof. means.

"Aluminum die-cast ADC12" is a plate sample in which a plate material made of an aluminum alloy (ADC12) is used as the base portion 11, and an aluminum sputtering layer (that is, the layered portion 12) is not formed on either surface. It means something.

"PPS-GF50-1" means that an aluminum sputtering layer (that is, the layered portion 12) is formed on either side of the base portion 11 made of PPS resin (general-purpose grade, thermal conductivity: 0.3 W/(mK)). means that it is a resin plate sample S1 in which is not formed.

“PPS-GF50-1+AL sputter 0.2 μ” means that 0.2 μm is applied only to the second main surface 15b side of the base portion 11 made of PPS resin (general-purpose grade, thermal conductivity: 0.3 W/(mK)). It means that it is a resin plate sample S1 on which a 2 μm aluminum sputtering layer (that is, the layered portion 12) is formed.

“PPS-GF50-1+AL sputter 1.0 μ” means that 1.0 μm is applied only to the second main surface 15b side of the base portion 11 made of PPS resin (general-purpose grade, thermal conductivity: 0.3 W/(mK)). It means that it is a resin plate sample S1 on which a 0 μm aluminum sputtering layer (that is, the layered portion 12) is formed.

"PPS-GF50-2" means that an aluminum sputtering layer (that is, the layered portion 12) is formed on either side of the base portion 11 made of PPS resin (general-purpose grade, thermal conductivity: 0.7 W/(mK)). means that it is a resin plate sample S1 in which is not formed.

“PPS-GF50-2+AL sputter 1.0 μ” means that 1.0 μm is applied only to the second main surface 15b side of the base portion 11 made of PPS resin (general-purpose grade, thermal conductivity: 0.7 W/(mK)). It means that it is a resin plate sample S1 on which a 0 μm aluminum sputtering layer (that is, the layered portion 12) is formed.

The phrase "PPS high thermal conductivity grade" means that aluminum sputtering layers (that is, the layered portion 12) are formed on both surfaces of the base portion 11 made of PPS resin (high thermal conductivity grade, thermal conductivity: 1.2 W/(mK)). means that it is a resin plate sample S1 in which is not formed.

The graph in FIG. 5 shows the results when using these. Each plate sample had a heat source temperature of about 10° C. at the start of the test. Starting from this temperature and heating each for 20 minutes, a large difference was observed in the final temperature reached. That is, the heat source temperature of "aluminum" and "aluminum die-cast ADC 12", which are basically made only of metal materials, did not rise much, and was about 40°C to 60°C.

When comparing resin plate samples S1 that use PPS resin but do not have an aluminum sputtering layer, the heat source temperature is about 150° C. for “PPS-GF50-1”, about 140° C. for “PPS-GF50-2”, and “ PPS high thermal conductivity grade" was about 110°C. Therefore, the result was obtained that the higher the thermal conductivity, the lower the heat source temperature.

In "PPS-GF50-1 + AL sputtering 0.2μ", the heat source temperature was about 148°C, which was almost the same as "PPS-GF50-1", while in "PPS-GF50-1 + AL sputtering 1.0μ" was as low as about 127°C. Therefore, when the type of PPS resin is the same, it was found that forming a thicker aluminum sputtering layer improves heat dissipation. In addition, the heat source temperature of "PPS-GF50-2 + AL sputtering 1.0 µm" was about 105°C, which was lower than "PPS-GF50-1 + AL sputtering 1.0 µm" and "PPS high thermal conductivity grade".

[Example 3] Investigation of changes in surface roughness due to sputtering layer formation

Here, it was investigated how the surface roughness of the second main surface 15b of the base portion 11 changes due to the formation of the aluminum sputtering layer. The results are shown in FIG. This graph shows the relationship between the thickness of the aluminum sputtering layer, which is the layered portion 12, and the surface roughness of the second main surface 15b. According to this, the Rz of the second main surface 15b was 1.274 μm and the Ra was 0.194 before the formation of the aluminum sputtering layer. On the other hand, when an aluminum sputtering layer having a thickness of 0.15 μm is formed, the surface of the aluminum sputtering layer has Rz of 0.883 μm and Ra of 0.166, both of which are smaller than the Rz and Ra values of the second main surface 15b. It turned out to be Furthermore, when an aluminum sputtering layer of 0.9 μm was formed, the Rz and Ra of the surface of the aluminum sputtering layer were 0.793 μm and 0.132, respectively. From the above, it was found that the smoothness of the surface 12a of the layered portion 12 can be made higher than the smoothness of the surface (resin surface) of the second main surface 15b by forming the aluminum sputtering layer.

Therefore, according to this embodiment, the following effects can be obtained.

(1) According to the resin molded product 1 of the present embodiment configured as described above, since the thermoplastic resin is exposed on the first main surface 15a, which is the mounting side of the electrical component 2, the base body is exposed to thermal radiation. The heat of the portion 11 is released to the outside. On the other hand, a layered portion 12 is formed on the second main surface 15b on which the heat receiving body 3 is attached, and the heat receiving body 3 is arranged to face the layered portion 12 therebetween. Moreover, the layered portion 12 is formed over an area larger than the outer dimensions of the electrical component 2 in plan view. Therefore, the layered portion 12 diffuses heat in the plane direction of the second main surface 15b and efficiently conducts heat to the heat receiving body 3 via the layered portion 12, thereby allowing the heat of the base portion 11 to escape to the outside. be Therefore, the cooling efficiency of the assembly 4 can be improved. In addition, in the resin molded product 1 of the present embodiment, the smoothness of the surface 12a of the layered portion 12 is higher than the smoothness of the surface of the second main surface 15b. is improved, and heat can be efficiently conducted to the heat receiving body 3 via the layered portion 12 . This can also contribute to an improvement in cooling efficiency.

(2) When the resin molded product 1 of the present embodiment is an insert molded product having a structure in which the bus bar 13 is held in the bus bar holding portion 14 of the base portion 11, the following effects are obtained. That is, since the busbars 13 are held in close contact with the base portion 11 without gaps, heat is efficiently transferred from the busbars 13, which are directly affected by the heat generated by the electrical components 2 as heat sources, to the base portion 11. can be moved. Therefore, being an insert-molded product in this way contributes to the improvement of cooling efficiency, as well as the reduction in size and weight of the entire product.

(3) The resin molded product 1 of the present embodiment is characterized in that the layered portion 12 is a metal sputtering layer. Since the metal sputtering layer has excellent adhesion of the layered portion 12 to the base portion 11, the heat diffused in the planar direction of the second main surface 15b is efficiently conducted to the heat receiving body 3 via the layered portion 12. can be made

It should be noted that the embodiment of the present invention may be modified as follows.

- In the above-described embodiment, the resin molded product 1 of the present invention is embodied as an electrical component casing for heat dissipation of the electrical component 2 such as a transistor, but it is of course not limited to this. For example, as in another embodiment shown in FIG. 7, the resin molded product 1A of the present invention can be embodied as a terminal block for attaching a battery terminal, which is a type of electrical component 2 as a heat source. This resin molded product 1A includes a base portion 11 having a wall portion 15. A layered portion 12 is formed on the second main surface 15b side of the wall portion 15 (right side in FIG. 7), and the layered portion An aluminum die-cast heat sink, which is the heat receiving body 3 , is attached via the portion 12 . On the other hand, the layered portion 12 is not formed on the first main surface 15a side of the wall portion 15 (the left surface side in FIG. 7), and the resin material is exposed. A terminal holding portion 15c protrudes from the first main surface 15a side of the wall portion 15, and a cylindrical terminal 21 is provided there. In the resin molded product 1A, a substantially L-shaped bus bar 13 is insert-molded while being held by a bus bar holding portion 14. As shown in FIG. One end of the bus bar 13 is connected to a columnar terminal 21 on the side of the first main surface 15a, and the other end protrudes outside through a flat cylindrical portion 22 protruding on the side of the second main surface 15b. ing.

In the above-described embodiment, the electrical component 2 as a heat source is a transistor or the like or a battery terminal, and an electrical component casing (resin molded product 1) or a terminal block (resin molded product 1A) for dissipating heat is mentioned. 1 shows an example embodying the present invention, but it is of course not limited to this. For example, the resin molded product of the present invention can be embodied as a circuit board casing for housing a circuit board or the like that functions as an ECU or PCU, or as a motor casing for housing a motor. .

- In the above-described embodiment, an example in which an aluminum sputtering layer is formed as the layered portion 12 is shown, but of course the present invention is not limited to this. , titanium, nickel, cobalt, chromium, tin, lead, etc.) may be selected to form the sputtered layer. Alternatively, the aluminum layer may be formed by film formation methods other than sputtering (for example, plating, chemical vapor deposition, sputtering, vacuum deposition, ion plating, etc.).

Next, in addition to the technical ideas described in the claims, technical ideas grasped by each of the above-described embodiments are listed below.

(1) In any one of claims 1 to 4, the layered portion is thinner than the base portion.
(2) In any one of claims 1 to 4, the thickness of the layered portion is 0.2 μm or more and 2.0 μm or less.
(3) In any one of claims 1 to 4, the wall portion has a thickness of 1 mm or more and 4 mm or less.
(4) In any one of Claims 1 to 4, the layered portion is made of aluminum.
(5) In any one of claims 1 to 4, the heat receiving member is an aluminum heat sink.
(6) In any one of claims 2 to 4, the surface roughness of the layered portion is smaller than the surface roughness of the second main surface.
(7) In any one of claims 2 to 4, the surface roughness (maximum height roughness Rz) of the layered portion is greater than the surface roughness (maximum height roughness Rz) of the second main surface. also be 40% or more smaller.
(8) In any one of Claims 1 to 4, the thermoplastic resin forming the base portion is a highly thermally conductive resin having a thermal conductivity of 1 W/(mK) or more.
(9) In any one of claims 1 to 4, the thermoplastic resin forming the base is made of PPS resin.

DESCRIPTION OF SYMBOLS 1, 1A... Resin molded product 2... Electric component 2a... Connecting part 3... Heat-receiving body 4... Assembled body 11... Base part 12... Layered part 13... Bus bar 14... Bus bar holding part 15... Wall part 15 a... First main surface 15 b … second main surface

Claims (4)

A resin molded product that constitutes at least a part of an assembly having an electrical component that is a heat source and a heat receiving body that receives heat generated by the electrical component, and that is interposed between the electrical component and the heat receiving body. and
a base portion made of a thermoplastic resin and having a wall portion;
A layered portion formed of a material having a higher thermal conductivity than the thermoplastic resin,
The wall portion is formed with a busbar holding portion capable of holding a busbar having a connection portion for connecting the electric component,
The wall portion has a first main surface on which the electrical component is attached, and a second main surface opposite to the first main surface and on which the heat receiving body is attached,
The thermoplastic resin forming the base portion is exposed on at least a portion of the first main surface of the wall portion,
The layered portion is formed on at least part of a position facing the heat receiving body on the second main surface of the wall portion,
A resin molded product, wherein the layered portion is formed over an area larger than an outer dimension of the electrical component in a plan view. 2. The molded resin article according to claim 1, wherein the smoothness of the surface of the layered portion is higher than the smoothness of the surface of the second main surface. 3. The resin molded product according to claim 1, wherein the resin molded product is an insert molded product having a structure in which the bus bar is held in the bus bar holding portion of the base portion. 4. The resin molded article according to claim 1, wherein the layered portion is a metal sputtering layer.

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