JP2019212906A - Resin molding - Google Patents

Abstract

To provide a resin molding that can be assembled to an assembly and that can improve the cooling efficiency of the assembly.SOLUTION: A resin molding 1 according to the present invention includes a base portion 11 formed of a thermoplastic resin and having a wall portion 15, and a layered portion 12 made of a material having a higher thermal conductivity than that of the base portion. On the wall portion 15, a bus bar holding portion 14 capable of holding a bus bar 13 having a connecting portion for attaching an electric component 2 is formed. On at least a part of a first main surface 15a of the wall portion 15 on the side where the electric component is mounted, the thermoplastic resin forming the base portion 11 is exposed. On at least a part of a position facing a heat receiver 3 on a second main surface 15b of the wall portion 15 on the side in which a heat receiving member is mounted, the layer portion 12 is formed. The layered portion 12 is formed over an area larger than the external dimensions of the electric component 2 in plan view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin molded article, and in particular, constitutes at least a part of an assembly including an electric component as a heat source and a heat receiving body that receives heat generated by the electric component, and is interposed between the electric component and the heat receiving body. It is related with the resin molded product arrange | positioned.

  A vehicle such as an electric vehicle (EV) or a hybrid vehicle (HV) is equipped with several assemblies having an electric component as a heat source and a heat receiving body that receives heat generated by the electric component. As a specific example, PCU (Power Control Unit) and ECU (Electronic Control Unit) and other electronic devices are housed in a special case to form a case assembly, which is installed in the engine room and indoors. This is well known in the art. Such a case assembly is configured by partially using a resin molded product having insulating properties, and an electronic device and a metal member (for example, a heat sink) as a heat receiving body are connected through the resin molded product. ing.

  Generally, a resin molded product constituting 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 in the base portion, for example, Provided by molding. And by connecting the terminal of the electrical component which comprises an electronic device with respect to this bus bar, an electronic device is mounted in a resin molded product.

  By the way, conventionally, when an electrical component such as an electronic device generates heat by energization, the bus bar connected thereto is also indirectly heated and the temperature rises. For this reason, unless the heat of the electrical parts and the bus bar is quickly radiated to the outside of the case assembly, the temperature rise inside the case assembly cannot be prevented, and the electrical parts cannot be protected from the heat. In addition, since the thermal burden on bus bars and resin molded products increases, it is necessary to increase the thickness and size of bus bars and resin molded products in order to respond to this. turn into.

  Thus, as the case assembly as described above, a structure in which a heat transfer film having insulating properties and heat conductivity is sandwiched between a resin molded product and a heat sink has been conventionally proposed (see, for example, Patent Document 1). ). According to this configuration, the heat of the electrical parts and the bus bar is conducted to the heat sink through the resin molded product and the heat transfer film, and is dissipated from the heat sink to the outside of the case assembly so that the electrical parts and the bus bar are cooled. It has become.

JP 2005-019434 A

  However, in the case of such a case assembly, although a heat transfer film having thermal conductivity or the like is used, the adhesion between the heat transfer film and the resin molded product, or the adhesion between the heat transfer film and the heat sink Sex was not enough. Therefore, there is a drawback that heat on the resin molded product side cannot be efficiently conducted to the heat sink side. Further, since the heat transfer film is mainly composed of a synthetic resin material, it has a drawback that its own thermal conductivity is low. From the above, conventionally, the case assembly cannot be cooled efficiently.

  This invention is made | formed in view of said subject, The objective is to provide the resin molded product which can be assembled | attached to an assembly and can improve the cooling efficiency of an assembly.

  In order to solve the above-mentioned problem, the invention described in means 1 comprises at least a part of an assembly including an electrical component that is a heat source and a heat receiving body that receives heat generated by the electrical component, and the electrical component and A resin molded article disposed between the heat receiving member and formed of a thermoplastic resin, and is formed of a base portion having a wall portion and a material having higher thermal conductivity than the thermoplastic resin. The wall portion is formed with a bus bar holding portion capable of holding a bus bar having a connecting portion for connecting the electric component, and the wall portion is a mounting side of the electric component. A first main surface and a second main surface opposite to the first main surface and the attachment side of the heat receiving body; and at least a part of the first main surface of the wall portion, The thermoplastic tree forming the base portion Is exposed, and the layered portion is formed at least at a part of the second main surface of the wall facing the heat receiving body, and the layered portion is a plan view of the electrical component. The gist of the present invention is a resin molded product characterized in that it is formed over an area larger than the outer dimensions of

Therefore, according to the invention described in the means 1, since the thermoplastic resin is exposed on the first main surface on the attachment side of the electrical component, the heat of the base portion is released to the outside by heat radiation. On the other hand, a layered portion is formed on the second main surface, which is the attachment side of the heat receiving body, and the heat receiving body is disposed so as to face the layered portion. In addition, the layered portion is formed over an area larger than the outer dimension of the electrical component in plan view. For this reason, the heat of the base portion is released to the outside by efficiently conducting heat to the heat receiving body through the layered portion while diffusing heat in the surface direction of the second main surface by the layered portion. 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 the means 2, since the adhesion between the base portion side and the heat receiving body side is improved, heat can be efficiently conducted to the heat receiving body through the layered portion.

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

  Therefore, according to the invention described in the means 3, since the bus bar is held in close contact with the base portion without a gap, heat from the bus bar directly affected by the heat generated by the electrical component as the heat source is applied to the base portion. Can be moved efficiently. Therefore, this contributes to an improvement in cooling efficiency, and also contributes to a reduction in the overall size and weight.

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

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

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

Schematic which shows the resin molded product of embodiment which actualized this invention. (A) is a principal part expanded sectional view which shows the mode of the interface of the 2nd main surface of a wall part and layered part in the resin molded product of embodiment, (b) is the state of the 2nd main surface before layered part formation. The principal part expanded sectional view shown. Schematic for demonstrating the method of a heat dissipation evaluation test in the Example which actualized embodiment. The heat | fever property evaluation test of an Example WHEREIN: The graph which shows the relationship between time and heat-source temperature at the time of changing the formation position of a layered part. The heat | fever property evaluation test of an Example WHEREIN: The graph which shows the relationship between time and heat source temperature at the time of changing the thickness of a layered part, and the thermal conductivity of a thermoplastic resin. The graph which shows the relationship between the thickness of a layered part, and the surface roughness of a 2nd main surface in the surface roughness change investigation test of an Example. Schematic which shows the resin molded product of another embodiment which actualized this invention.

  Hereinafter, a resin molded product according to an embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a schematic view of a resin molded product 1 of the present embodiment. As shown in FIG. 1, the resin molded product 1 is a member constituting at least a part of a case assembly 4 having an electrical component 2 that is a heat source and a heat receiving body 3 that receives heat generated by the electrical component 2. is there. This resin molded product 1 is used in a state of being interposed between the electric component 2 and the heat receiving body 3. More specifically, the case assembly 4 in the present embodiment is a vehicle-mounted case assembly 4 disposed in the engine room. The resin molded product 1 is an electrical component casing for radiating heat from the 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 electrical component 2 that is a heat source, and here is a PCU case made of aluminum die cast 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 a fastening means such as a bolt.

  The resin molded product 1 includes a base portion 11, a layered portion 12, a bus bar 13, a bus bar holding portion 14, and the like.

  The base portion 11 constituting the resin molded product 1 is a member having a wall portion 15 having a relatively large area, for example. The wall 15 includes a first main surface 15a (upper surface in FIG. 1) on the mounting side of the electrical component 2, and a second main surface on the opposite side of the first main surface 15a and on the mounting side of the heat receiving body 3. 15b (lower surface in FIG. 1). Although the shape of the wall part 15 is not specifically limited, For example, it is preferable that it is a plate-shaped part, and it is more preferable that it is a plate-shaped part which has an area substantially equal to the external dimension in planar view of the base | substrate part 11 especially. This is because the wall portion 15 having such a shape is suitable not only as a mounting location of the electrical component 2 but also as a location for forming the layered portion 12. In addition, the wall part 15 does not necessarily need to be flat, for example, may be curving or having a step.

  The thickness of the wall portion 15 is arbitrary and is not particularly limited. For example, it is preferably 1 mm or more and 4 mm or less, and by setting the thickness within this range, a desired shape can be obtained while ensuring desired insulation. It can be obtained by molding. If the thickness is less than 1 mm, desired insulation and mechanical strength may not be ensured. On the other hand, if it exceeds 4 mm, sink marks may occur easily during molding. Note that 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, a lightweight and insulating synthetic resin is selected in view of being used as a part of the case assembly 4 for mounting on a vehicle. Moreover, as a forming method for obtaining the base portion 11, various conventionally known methods can be employed. Specifically, for example, not only a technique using a mold such as press molding or injection molding, but also a technique not using a mold (cutting, 3D printing, etc.) is allowed. Here, as the suitable base | substrate part 11, the injection molded product made from a thermoplastic resin can be mentioned. This is because an injection-molded product made of a thermoplastic resin is excellent in moldability, cost, lightness, workability, insulation, and the like. Specific examples of the thermoplastic resin include a PPS resin, a PBT resin, a PA resin, a PP resin, a PPE resin, and an ABS resin. Among these, it is preferable to select a PPS resin. This is because the PPS resin is a general-purpose resin that has excellent heat resistance and a relatively small linear expansion coefficient. In addition to this, the PPS resin has good compatibility with many metal materials including aluminum, so that the adhesion of the layered portion 12 can be improved. Here, it is preferable to select an injection-molded article made of a material containing inorganic particles or inorganic fibers in the matrix of PPS resin as the base portion 11, and thereby, the shape stability and the adhesiveness of the layered portion 12 are high. Is easier to obtain.

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

  The bus bar 13 constituting the resin molded product 1 is a conductor portion mainly for connecting the power source and the electrical component 2 and is formed by punching a conductive plate material by a press or the like. As the conductive plate material forming the bus bar 13, a plate material made of at least one metal selected from copper, copper alloy (such as brass), aluminum and the like is used. The bus bar 13 is installed on the base body 11 in a state where at least a part is held by a bus bar holding part 14 formed on the wall part 15. In this case, the base portion 11 having the groove-shaped or hole-shaped bus bar holding portion 14 may be prepared in advance, and a molded product having a structure in which the bus bar 13 manufactured separately is attached thereto. There may be. That is, it is possible to have a structure in which the bus bar 13 is held in a close contact state at a predetermined position (the bus bar holding portion 14) in the base portion 11 by performing the injection molding of the base portion 11 with the bus bar 13 placed in the mold. Good.

  The bus bar 13 has a connecting portion 13a at a portion exposed on the first main surface 15a side on which the electric component 2 is attached. And as a result of connecting the terminal 2a of the electrical component 2 to this connection part 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 an arbitrary shape depending on the application. The terminal 2a and the bus bar 13 are connected by fastening means such as bolts, soldering, wire bonding or the like. 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 constituting 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 part of the position facing the heat receiving body 3 on the second main surface 15 b of the wall portion 15. In other words, the layered portion 12 may be formed so as to cover a part of the second main surface 15b of the wall portion 15 or may be formed so as to cover the whole. Further, the layered portion 12 is formed on the second main surface 15b of the wall portion 15 over an area larger than the outer dimension in plan view of the electrical component 2 that is a heat source. 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 part 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 heat radiation from the first main surface 15a side. In other words, a part 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 formed of a material having a higher thermal conductivity than the thermoplastic resin that forms the base portion 11. With such a material, heat on the base body 11 side is efficiently conducted to the heat receiving body 3 side through the layered portion 12 while diffusing heat in the surface direction of the second main surface 15b by the layered portion 12. Because you can. 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 have a large degree of freedom in material selection. Specific examples of such metal layers include, for example, metal layers made of gold, silver, copper, platinum, iron, aluminum, titanium, nickel, cobalt, chromium, tin, lead, and the like, and alloys containing these metals as components. A layer (for example, a stainless alloy layer, a solder alloy layer, etc.) can be mentioned. Among these, an aluminum layer is particularly preferable. This is because aluminum has a high thermal conductivity and is advantageous for heat dissipation, and also contributes to cost reduction because it is an inexpensive metal material, and contributes to weight reduction because of its relatively light weight. Examples of the ceramic layer include an alumina layer, an aluminum nitride layer, a silicon nitride layer, a boron nitride layer, a silicon carbide layer, and a mullite layer.

  The metal layer typified by aluminum is, for example, a conventionally known film formation method, specifically plating, chemical vapor deposition (CVD), sputtering, vacuum vapor deposition, ion plating, or the like, on the surface 11a of the base portion 11. It is formed by various methods such as physical vapor deposition (PVD). In addition, a film made of a material having a high thermal conductivity when forming the base portion 11, a method of applying a liquid material containing a metal by a roll coating method, a spray coating method, or a curtain coating method, a method of printing the liquid material, It is also possible to employ a method of integrating the surface with the surface 11a. According to these methods, a thin, uniform, and intimately adhered layer can be formed relatively easily. The metal layer is preferably formed by a physical film formation method such as sputtering among the methods mentioned above. This is because the metal thin film (sputtering layer) formed by the sputtering method or the like is excellent in adhesion to the base portion 11 even if it is thin. Moreover, since the sputtering layer does not generate burrs, there is also a merit that there is no possibility of foreign matter mixing.

  The thickness of the metal layer (for example, an aluminum layer) as the layered portion 12 is not limited and is arbitrary. As the layer portion 12 is thicker, better thermal conductivity can be imparted. It is formed thinner than the wall portion 15) having a thickness of 1 mm to 4 mm. This is because, when the metal layer is thicker than the base portion 11, the use ratio of the metal material to the synthetic resin material is increased, and as a result, it is difficult to reduce the cost and weight of the entire resin molded product 1.

  The thickness of the metal layer (for example, an aluminum sputtering layer) 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 good that it is 1.0 micrometer or less. The reason is that the metal layer itself can be very thin in spite of good thermal conductivity, so that cost and weight can be effectively reduced. Here, if the thickness exceeds 2.0 μm, it may be difficult to effectively reduce the cost and weight. On the other hand, if the thickness is less than 0.1 μm, it may be difficult to impart desired heat conductivity, or the layer portion 12 may be peeled off and the base portion 11 may be easily exposed. Moreover, it is because there exists a possibility that the layer part 12 cannot fully fill the fine unevenness | corrugation of the 2nd main surface 15b.

  When the layered portion 12 is an aluminum layer, the resin molded product 1 is preferably configured in combination with the base body portion 11 made of an injection molded product made of PPS resin. As described above, since the PPS resin has good compatibility with aluminum, the adhesion of the layered portion 12 to the base portion 11 can be improved.

  2A is an enlarged cross-sectional view of the main part showing the interface between the second main surface 15b of the wall 15 and the layered portion 12, and FIG. 2B is a second view before the layered portion 12 is formed. It is a principal part expanded sectional view which shows the mode of the main surface 15b. As shown in FIG. 2 (b), the smoothness of the second main surface 15b of the wall 15 basically depends on the smoothness of the molding surface of the mold, but usually there are fine irregularities. For example, Rz (maximum height roughness) is 1.00 μm or more, and Ra (arithmetic average 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 major surface 15b, the fine irregularities of the second major surface 15b are 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 major surface 15b. In other words, the surface roughness of the layered portion 12 is smaller than the surface roughness of the second major surface 15b. With such a configuration, not only the unevenness of the surface 12a of the layered portion 12 is reduced, but the contact state with the heat receiving body 3 is increased, and the unevenness of the second main surface 15b is filled with the layered portion 12. The contact state between the layered portion 12 and the wall portion 15 is also increased. Therefore, the heat on the base body 11 side can be efficiently transmitted to the heat receiving body 3 side. 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 of the present embodiment will be described 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, the difference in heat dissipation when the formation position of the layered portion 12 in the base portion 11 was changed was investigated.

  FIG. 3 is a schematic diagram for explaining a test apparatus used in the heat dissipation evaluation test. This test apparatus is provided with a rectangular flat resin plate sample S1 (vertical 120 mm × horizontal 60 mm × thickness 2 mm) as a base portion 11, on the upper surface (first main surface 15 a) side that is the surface on the heat source side. A heat source H1 corresponding to an electrical component is placed in the center. Specifically, an iron block (length 48 mm × width 28 mm × thickness 9 mm) in which a heater is incorporated is used as the heat source H1. In order to measure the temperature of the heat source H1, heat source temperature measuring means T1 having a thermocouple t1 is provided. On the other hand, a heat sink HS1 (vertical 90 mm × width 70 mm × thickness 25 mm) cooled by water flow is disposed as a heat receiving body on the lower surface (second main surface 15b) side, which is a cooling side surface of the resin plate sample S1. ing. And using such a test apparatus, while always cooling by water flow, setting the heater output to a constant (80 W) and constantly raising the temperature for a predetermined time, the temperature of the heat source H1 is changed over time. It was measured. The graph of 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 one or both of the upper and lower surfaces of the resin plate sample S1 made of a commercially available PPS resin.

  In FIG. 4, “PPS-GF50-1” means that an aluminum sputtering layer (on both sides of the base portion 11 made of PPS resin (general grade, thermal conductivity: 0.3 W / (mK)) ( That is, it means that the resin plate sample S1 has no layered portion 12).

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

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

  “PPS-GF50-1 + sputtering 0.2 μ double-sided” means that a 0.2 μm aluminum sputtering 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 11. It means that it is the formed resin plate sample S1.

  The results when these are used are shown in the graph of FIG. In each resin plate sample S1, the heat source temperature at the start of the test was about 10 ° C. When heating was carried out for 20 minutes each starting from this temperature, all reached a temperature of 120 ° C. or higher, but compared with “PPS-GF50-1” having no aluminum sputtering layer, “PPS-GF50-” The heat source temperature was slightly higher for “1 + sputter 0.2 μ single side: heat source side” and “PPS-GF50-1 + sputter 0.2 μ double side”. Therefore, it was found that in these resin plate samples S1, the formation position of the aluminum sputtering layer is not appropriate, which leads to a decrease in heat dissipation. On the other hand, “PPS-GF50-1 + sputtering 0.2 μ single side: cooling side” had a slightly lower heat source temperature than “PPS-GF50-1” having no aluminum sputtering layer. Therefore, it is expected that forming the aluminum sputtering layer only on the second main surface 15b side and exposing the resin material without forming the first main surface 15a side will lead to improved heat dissipation. .

  The above results were considered as follows. That is, the heat release from the heated heat source H1 is performed by two methods via the base body 11. The first heat dissipation 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 dissipation route is from the second main surface 15b of the base portion 11 to the heat sink HS1. The route is to conduct heat. The former contributes to the thermal emissivity of the resin molded product 1, and the latter contributes to the thermal conductivity of the resin molded product 1. Based on the above, it is effective to increase both the thermal emissivity and the thermal conductivity in order to increase the heat dissipation efficiency. Here, it is known that the thermal emissivity is generally higher in the resin than in the metal, whereas the thermal conductivity is generally higher in the metal than the resin. Accordingly, by forming an aluminum sputtering layer only on the second main surface 15b side of the base portion 11 as in “PPS-GF50-1 + sputtering 0.2 μ single side: cooling side”, heat on the second main surface 15b side is formed. While increasing the conductivity and promoting the diffusion of heat, it was considered possible to increase the thermal emissivity on the first main surface 15a side. On the other hand, if an aluminum sputtering layer is formed as in “PPS-GF50-1 + sputter 0.2 μ single side: heat source side” or “PPS-GF50-1 + sputter 0.2 μ double side”, the heat source H1 side (air Side) would be a metal surface with a low thermal emissivity, and it was considered that the thermal radiation from the heat source H1 side would decrease.

[Example 2] Heat dissipation evaluation test 2

  In this heat dissipation evaluation test 2, the difference in heat dissipation when the thickness of the layered portion 12 in the base portion 11 and the thermal conductivity of the thermoplastic resin were changed was investigated. As a test apparatus, the same thing as said heat dissipation evaluation test 1 was used, and the temperature of heat source H1 was measured with time by the same method. The graph of FIG. 5 shows the relationship between time and heat source temperature.

  In FIG. 5, “aluminum” refers to a plate sample in which an aluminum plate material is used as the base portion 11 and an aluminum sputtering layer (that is, the layered portion 12) is not formed on either side thereof. I mean.

“Aluminum die-cast ADC12” is a plate sample in which a plate 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 side thereof. It means that there is.

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

  “PPS-GF50-1 + AL sputter 0.2 μm” is defined as 0 on the second main surface 15b side of the base portion 11 made of PPS resin (general grade, thermal conductivity: 0.3 W / (mK)). It means that the resin plate sample S1 is formed with a 2 μm aluminum sputtering layer (that is, the layered portion 12).

  “PPS-GF50-1 + AL sputter 1.0 μm” is defined only on the second main surface 15b side of the base portion 11 made of PPS resin (general grade, thermal conductivity: 0.3 W / (mK)). This 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” refers to an aluminum sputtering layer (that is, the layered portion 12) on either side of the base portion 11 made of PPS resin (general grade, thermal conductivity: 0.7 W / (mK)). Means that the resin plate sample S1 is not formed.

  “PPS-GF50-2-AL spatter 1.0 μm” is defined only on the second main surface 15b side of the base portion 11 made of PPS resin (general grade, thermal conductivity: 0.7 W / (mK)). This 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 high thermal conductivity grade” means that an aluminum sputtering layer (ie, layered portion 12) is formed on either side of the base portion 11 made of PPS resin (high thermal conductivity grade, thermal conductivity: 1.2 W / (mK)). Means that the resin plate sample S1 is not formed.

  The results when these are used are shown in the graph of FIG. Each plate sample had a heat source temperature of about 10 ° C. at the start of the test. When starting from this temperature and heating for 20 minutes each, a large difference was observed in the final temperature. That is, the heat source temperatures of “aluminum” and “aluminum die-cast ADC12” basically composed of only a metal material were not so high, and were about 40 ° C. to 60 ° C.

  When the PPS resin is used but the resin plate samples S1 having no aluminum sputtering layer are compared, the heat source temperature is about 150 ° C. for “PPS-GF50-1”, about 140 ° C. for “PPS-GF50-2”, “ It was about 110 ° C. for the “PPS high thermal conductivity grade”. Therefore, the result that heat source temperature became low, so that heat conductivity was high was obtained.

  In “PPS-GF50-1 + AL sputtering 0.2 μ”, the heat source temperature was about 148 ° C., which was almost the same as “PPS-GF50-1”, whereas in “PPS-GF50-1 + AL sputtering 1.0 μ”, the heat source temperature was Was as low as about 127 ° C. Therefore, when the kind of PPS resin was the same, it turned out that heat dissipation improves by forming the aluminum sputtering layer thickly. In “PPS-GF50-2 + AL Sputter 1.0 μ”, the heat source temperature was about 105 ° C., which was lower than “PPS-GF50-1 + AL Sputter 1.0 μ” and “PPS High Thermal Conductivity Grade”.

[Example 3] Investigation of change 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 result is 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 major surface 15b. According to this, Rz of the 2nd main surface 15b was 1.274 micrometers and Ra was 0.194 in the step before formation of an aluminum sputtering layer. On the other hand, when an aluminum sputtering layer of 0.15 μm is formed, Rz on the surface of the aluminum sputtering layer is 0.883 μm and Ra is 0.166, both of which are smaller than the Rz and Ra values of the second main surface 15b. I found out that Further, when a 0.9 μm aluminum sputtering layer was formed, it was found that Rz on the aluminum sputtering layer surface was 0.793 μm and Ra was 0.132, both of which were further reduced. 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 the present 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 on the mounting side of the electrical component 2, the substrate is exposed by heat radiation. The heat of the part 11 is released to the outside. On the other hand, the layered portion 12 is formed on the second main surface 15 b on the attachment side of the heat receiving body 3, and the heat receiving body 3 is disposed so as to face the layered portion 12. In addition, the layered portion 12 is formed over a larger area than the outer dimension of the electrical component 2 in plan view. Therefore, heat is efficiently conducted to the heat receiving body 3 through the layered portion 12 while diffusing heat in the surface direction of the second main surface 15b by the layered portion 12, so that the heat of the base portion 11 is released to the outside. It is. Therefore, the cooling efficiency of the assembly 4 can be improved. Moreover, in the resin molded product 1 of this embodiment, since the smoothness of the surface 12a of the layer part 12 is higher than the smoothness of the surface of the 2nd main surface 15b, the adhesiveness of the base | substrate part 11 side and the heat receiving body 3 side. Therefore, heat can be efficiently conducted to the heat receiving body 3 through 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 by the bus bar holding portion 14 in the base portion 11, the following effects are exhibited. That is, since the bus bar 13 is held in close contact with the base body 11 without a gap, heat is efficiently transmitted from the bus bar 13 directly affected by the heat generated by the electrical component 2 as a heat source to the base body 11. Can be moved. Therefore, such an insert-molded product contributes to the improvement of cooling efficiency and also contributes to the reduction in size and weight of the whole.

  (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 is excellent in the adhesion of the layered portion 12 to the base portion 11, the heat diffused in the surface direction of the second main surface 15 b is efficiently conducted to the heat receiving body 3 through the layered portion 12. Can be made.

  In addition, you may change embodiment of this invention as follows.

  In the above embodiment, the resin molded product 1 of the present invention is embodied as an electrical component casing for radiating heat with respect to the electrical component 2 such as a transistor. However, the present invention is not limited to this. For example, as in another embodiment shown in FIG. 7, the resin molded product 1 </ b> A of the present invention can be embodied as a terminal block for attaching a battery terminal that is a kind of the electrical component 2 that is 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 (right side in FIG. 7) of the wall portion 15 and the layered portion is formed. A heat sink made of aluminum die cast as the heat receiving body 3 is attached via the portion 12. On the other hand, the layer portion 12 is not formed on the first main surface 15a side (left surface side in FIG. 7) of the wall portion 15, and the resin material is exposed. A terminal holding portion 15c is projected on the first main surface 15a side of the wall portion 15, and a columnar terminal 21 is provided there. The resin molded product 1 </ b> A is insert-molded in a state where a substantially L-shaped bus bar 13 is held by the bus bar holding portion 14. One end of the bus bar 13 is connected to a cylindrical terminal 21 on the first main surface 15a side, and the other end penetrates a flat cylindrical portion 22 projecting on the second main surface 15b side and protrudes to the outside. ing.

  In the above embodiment, the case where the electrical component 2 that is a heat source is a transistor or the like or a battery terminal is exemplified, and an electrical component casing (resin molded product 1) or a terminal block (resin molded product 1A) for radiating heat about these. Although the example which actualized this invention was shown in this, of course, it is 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 embodiment, an example in which an aluminum sputtering layer is formed as the layered portion 12 has been shown. However, the present invention is not limited to this, and a metal other than aluminum (for example, gold, silver, copper, platinum, iron, aluminum) , Titanium, nickel, cobalt, chromium, tin, lead, etc.) may be selected to form the sputtering layer. Alternatively, the aluminum layer may be formed by a film forming method other than sputtering (for example, plating, chemical vapor deposition, sputtering, vacuum vapor deposition, ion plating, etc.).

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the respective embodiments described above 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 not less than 0.2 μm and not more than 2.0 μm.
(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 body 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. 40% or less.
(8) In any one of claims 1 to 4, the thermoplastic resin forming the base portion is a high thermal conductivity 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 portion is made of PPS resin.

DESCRIPTION OF SYMBOLS 1, 1A ... Resin molded product 2 ... Electrical component 2a ... Connection part 3 ... Heat receiving body 4 ... Assembly 11 ... Base | substrate part 12 ... Layered part 13 ... Bus bar 14 ... Bus bar holding part 15 ... Wall part 15a ... 1st main surface 15b ... Second main surface

Claims (4)

A resin molded product that constitutes at least a part of an assembly including an electrical component that is a heat source and a heat receiving body that receives heat generated by the electrical component, and is disposed between the electrical component and the heat receiving body. Because
A base portion formed 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,
A bus bar holding part capable of holding a bus bar having a connecting part for connecting the electric parts is formed on the wall part,
The wall portion includes a first main surface that is an attachment side of the electrical component, and a second main surface that is an opposite side of the first main surface and is an attachment side of the heat receiving body,
In at least a part of the first main surface of the wall portion, the thermoplastic resin forming the base portion is exposed,
The layered portion is formed in at least a portion of the second main surface of the wall portion facing the heat receiving body,
The resin-molded product, wherein the layered portion is formed over an area larger than an outer dimension of the electrical component in plan view.   The resin molded product 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.   The resin molded product according to claim 1 or 2, wherein the resin molded product is an insert molded product having a structure in which the bus bar is held by the bus bar holding portion in the base portion.   4. The resin molded product according to claim 1, wherein the layered portion is a metal sputtering layer.