JP5899634B2 - Composite structure - Google Patents

Description

  The present invention relates to a composite structure in which a metal member and a resin member are combined, and more particularly, to a structure that constitutes a storage case that is excellent in heat dissipation for storing electronic / electrical parts, for example.

  Conventionally, storage cases for electronic / electrical parts have been changed from metal materials to resin materials from the viewpoints of weight reduction, economy, and the like. However, since the resin material has poor heat dissipation, if the case is entirely made of resin, the heat generated from the electronic / electrical components housed in the case cannot be efficiently dissipated to the outside. In particular, in an environment exposed to high temperatures, such as in an engine room of an automobile, the temperature inside the case becomes even higher due to heat generated from electronic / electrical components housed inside the case. Therefore, in order to efficiently release the heat inside the case to the outside, heat is radiated by configuring a part of the storage case with a metal material.

  FIG. 5 is a diagram schematically showing an example of a storage case for electronic / electrical parts. The storage case 50 includes a metal substrate 53 having a heat radiation function such as an aluminum plate and a resin case portion 52, and an electronic component 51 is thermally coupled to the metal substrate 53. A flange surface is formed on the resin case portion 52 and the metal substrate 53, and the whole storage case is sealed by tightening with a bolt 54 via a sealing material (gasket) such as silicone resin.

  However, in this structure, a female substrate is processed or a through hole is formed on the metal substrate for tightening the bolt, and a silicone sealing agent is applied to the mating surface between the metal substrate and the resin case part. Since it is necessary to bolt several places together, there is a problem that the assembly is very troublesome. Moreover, it is necessary to remove the bolts and separate the metal part and the resin part even at the time of disposal, which is very troublesome. In addition, the sealing agent is not preferable at the time of material recycling, whether it remains in the metal base or the resin case.

  In Patent Document 1, a resin is molded so that a metal case main body exposed portion is formed as a housing case for accommodating an electronic circuit board therein, and an adhesive is provided so as to cover the interface between the case main body exposed portion and the resin portion. A coated electronic circuit board housing case is described. In this structure, the tightening process using bolts is not necessary, and therefore, the labor of assembling can be saved. In addition, by using an adhesive, it is intended to ensure the airtightness of the joint surface between the metal and the resin, but it takes time and effort to seal the interface between the metal and the resin with an adhesive. Application may be very difficult.

JP 2002-134931 A

  The present invention has been made in view of such problems, and provides a composite structure that requires only a small number of parts, can greatly reduce the assembly time, and has high airtightness at the joint surface between the metal and the resin. The purpose is to do.

  The present invention relates to the following matters.

1. A composite structure formed by joining a metal member and a resin member,
The linear expansion coefficient of the first resin member present at the location where the metal member is joined is in the range of 0.5 to 1.5 times the linear expansion coefficient of the metal member in the range of 20 ° C to 150 ° C. A composite structure characterized by being.

  2. 2. The composite structure according to claim 1, wherein the resin member contains a resin component and an inorganic filler component, and the amount of the inorganic filler component is selected so as to have a linear expansion coefficient in the range.

  3. 3. The composite structure according to 2 above, wherein the inorganic filler is glass fiber or carbon fiber.

  4). 3. The composite structure according to 2 above, wherein the resin component constituting the resin member is a polyamide resin.

  5. 5. The composite structure according to claim 1, wherein the metal member is aluminum processed by die casting.

6). A method for producing a composite structure in which a metal member and a resin member are joined at a joint,
Installing the metal member in a mold for insert molding;
Injecting a molten first resin member into the mold, and molding the first resin member so that the metal member and the first resin member are joined at a joint portion;
Have
In the range of 20 ° C. to 150 ° C., the first resin member has a linear expansion coefficient in the range of 0.5 to 1.5 times the linear expansion coefficient of the metal member. Method.

  7). The manufacturing of the composite structure according to claim 6, further comprising a step of welding a first resin member formed by bonding to the bonding portion and a second resin member previously formed in a desired shape. Method.

  8). 8. The method for producing a composite structure according to 6 or 7, wherein when the molten first resin member is injected, the metal member is preheated to substantially the same temperature as the mold.

  Since the composite structure of the present invention does not require bolting or the like for joining the metal member and the resin member, it is possible to reduce the types of components, and therefore the assembly time can be greatly shortened. Furthermore, the airtightness between the metal member and the resin member is excellent. Moreover, since it is easy to separate a metal member and a resin member at the time of disposal, it is excellent also in recyclability.

It is a figure which shows one example of the composite structure of this invention. (A) Cross section, (b) Back view It is process drawing of an example of the manufacturing process of a composite structure. (A) Cross section, (b) Back view It is process drawing of an example of the manufacturing process of a composite structure. It is sectional drawing which shows the completed structure of one example of the manufacturing process of a composite structure. It is sectional drawing which shows the conventional storage case of an electronic / electrical component. It is a graph which shows the measurement result of the linear expansion coefficient of resin used in Example 1 and Comparative Example 1.

  FIG. 1 shows an example of the composite structure of the present invention. FIG. 1A is a cross-sectional view, and FIG. 1B is a back view as viewed from the bottom of FIG. The composite structure 10 includes a metal member 13 and a resin member 12, and the resin member 12 is formed by welding a first resin member 12a and a second resin member 12b. The composite structure 10 is, for example, a storage case for electronic / electrical parts, and an electronic part 11 thermally coupled to a metal member 13 is disposed therein.

  As shown in the figure, the first resin member 12 a is bonded to the metal member 13. A portion where the metal member 13 and the first resin 12a are joined is hereinafter referred to as a joined portion. In the joint portion, no adhesive is used, and the metal member and the first resin member are in close contact with each other.

  In the present invention, the linear expansion coefficient of the metal member and the first resin member is such that the linear expansion coefficient of the first resin member is in the range of 0.5 to 1.5 times the linear expansion coefficient of the metal member. Since the relationship between the linear expansion coefficients is within this range, the metal member and the first resin member are less affected by thermal expansion / cooling shrinkage even when used in an environment with a large temperature difference such as an engine room of an automobile. Airtightness can be maintained between. In addition, since a dimensional shift can be almost eliminated even during molding as described later, a highly airtight composite structure between the metal member and the first resin member can be formed. More preferably, the linear expansion coefficient of the first resin member is in the range of 0.8 to 1.2 times the linear expansion coefficient of the metal member.

  The linear expansion coefficient is a value measured in the range of 20 ° C. to 150 ° C. Usually, the expansion coefficient in this range (ΔL / L; ΔL is elongation, L is the test sample length) divided by the temperature range. If the obtained linear expansion coefficient is in the above range, there is almost no influence of thermal expansion / contraction during molding.

In both the metal member and the first resin member, the average linear expansion coefficient may change depending on the temperature range. For example, the average linear expansion coefficient of the aluminum alloy 2014 is as follows.
−196 to −60 ° C .: 1.53 × 10 ⁻⁵ (1 / ° C.)
−60 to + 20 ° C .: 2.14 × 10 ⁻⁵ (1 / ° C.)
+20 to + 100 ° C .: 2.30 × 10 ⁻⁵ (1 / ° C.)
+100 to + 200 ° C .: 2.36 × 10 ⁻⁵ (1 / ° C.)
Therefore, when the average linear expansion coefficient in the temperature range of 20 ° C. to 150 ° C. is compared, the linear expansion coefficient of the metal member and the first resin member is in the above relationship, and the temperature of 20 ° C. to 150 ° C. When the linear expansion coefficient at each temperature in the range is compared, the linear expansion coefficient between the metal member and the first resin member is the above relationship (range of 0.5 to 1.5 times, preferably 0.8 to 1.2). It is preferable that it is in the range of twice.

  Further, the average linear expansion coefficient over the entire temperature range in which the composite structure is used, more preferably, the linear expansion coefficient of the metal member and the first resin member is in the above relationship with respect to the linear expansion coefficient at each temperature. preferable. For example, in an application used in an engine room of an automobile, it is in a range of −40 ° C. to 130 ° C.

  Examples of the metal material constituting the metal member include general cold-rolled steel, special cold-rolled steel, high-strength steel for automobiles, hot-rolled steel, surface-treated steel, high-strength steel, special steel, stainless steel, aluminum, and high strength. It is preferably at least one selected from the group consisting of aluminum, duralumin, and ultraduralumin. Note that high-strength steel includes Duel-Phase steel and TRIP steel. Particularly preferred is aluminum. The method for forming the metal member is not particularly limited, but die casting, particularly die casting using aluminum is preferable as a method for forming various shapes at a relatively low cost.

  The first resin member preferably contains an inorganic filler for adjusting the linear expansion coefficient in addition to the resin component (matrix resin). There is no restriction | limiting in particular as a resin component in a 1st resin member, Arbitrary resin can be used according to the characteristic and shaping | molding required for each member. Preferred resins include, for example, polyamide resin, polyacetal resin, polycarbonate resin, polyether resin, polyester resin, polypropylene, ABS resin and the like. These resins may be used alone or in combination of two or more. Particularly preferred resins when used alone include polyamide resins and polypropylene. Specific examples of the polyamide resin include aliphatic polyamides such as nylon 6, nylon 66, nylon 11 and nylon 12, and semi-aromatic polyamide resins such as polyhexamethylene terephthalamide and polyhexamethylene isophthalamide. Can be mentioned. These resins may consist of one or two or more copolymers. Among the polyamide resins, nylon 6 and nylon 66 are preferable.

  Examples of the inorganic filler include glass fiber, carbon fiber, silica, alumina, aluminosilicate, silicon nitride, clay, talc, mica, kaolin, calcium carbonate, magnesium carbonate and the like. Preferably, it is in the form of fibers (including whiskers) functioning as a reinforcing material for the resin component, particularly glass fibers or carbon fibers, and most preferably glass fibers. The inorganic filler is added in such a range that the first resin member has the above-mentioned predetermined linear expansion coefficient and preferably does not hinder the meltability of the resin during insert molding as will be described later.

  When glass fiber is used, it is preferably added in an amount of 15 to 45 parts by weight, more preferably 20 to 40 parts by weight, and most preferably 25 to 35 parts by weight with respect to 100 parts by weight of the resin component.

  In addition, when the linear expansion coefficient of the first resin member has anisotropy, that is, when the linear expansion coefficient differs depending on the direction, at least one linear expansion coefficient has a linear expansion with the metal member as described above. It only needs to satisfy the coefficient relationship. By aligning the direction in which the linear expansion coefficient is close to that of the metal member with the direction in which thermal expansion / cooling shrinkage is a problem, the problem of thermal expansion / cooling shrinkage can be solved in most applications. For example, as shown in FIG. 1, when the first resin member 12 a surrounds the metal member 13, the linear expansion coefficient in the peripheral direction of the first resin member 12 a may be close to the linear expansion coefficient of the metal member. preferable. More specifically, when the metal member 13 is square, the linear expansion coefficient of the first resin member 12a has a relationship defined by the present invention in the length direction of each of the four sides. preferable. That is, it is preferable that the linear expansion coefficient is formed so that the direction close to the metal is in a suitable direction at each location in the first resin member 12a.

  The second resin member is formed of the same or different material as the first resin member. Examples of the resin component constituting the second resin member include resins suitable for the first resin member described above, and preferred resins are also the same. As will be described later, since the first resin member and the second resin member are preferably joined by welding, the first and second resin components are selected so that at least the two resin components have compatibility. Preferably, the resin components of the first resin member and the second resin member are the same. Here, the resins are mutually “compatible” means that the difference in solubility parameter between one resin and the other resin is small, specifically 1.4 or less, preferably 1.2 or less. Preferably it is 1.0 or less, and it means that both molecular chains can be mixed. Here, the solubility parameter (Sp) value is calculated from the polymer skeleton by the method of Fedors (see documents such as R. F. Fedors, Poly. Eng. And Sci., 14 (2), 147 (1974)). The

  Further, since the second resin member is not joined to the metal member (meaning that the airtightness between the resin and the resin is a problem as in the metal member 13 in FIG. 1). ), There is no particular requirement for the linear expansion coefficient. Therefore, it is not necessary to contain an inorganic filler such as glass fiber, but if the linear expansion coefficient with the first resin member is greatly different, the linear expansion coefficient of the metal member will be greatly different. As will be understood, an excessive force is applied to the joint between the metal member and the first resin member due to a difference in thermal expansion between the entire resin member 12 and the metal member 13 as the temperature changes, or the resin member is distorted. Sometimes. Therefore, generally, it is preferable to contain an inorganic filler so that the second resin member also has a linear expansion coefficient that is the same as or close to that of the first resin member. A preferable inorganic filler and amount are the same as those of the first resin member described above. In a preferred embodiment, the first resin member and the second resin member are made of the same material (the blending of the resin component and the inorganic filler is the same). Specifically, it is most preferable that both the first resin member and the second resin member are glass fiber reinforced nylon 6.

  Regarding the shapes of the first resin member and the metal member, it is preferable that the first resin member and the metal member are fitted in the joint portion. In the joint portion, when a force is applied in a substantially vertical direction to the joint surface between the metal member and the first resin member, the joint portion has a shape that can resist peeling. As shown in FIGS. 1 (a) and 1 (b), the simplest form of fitting is as follows. The first resin member surrounds the end of the metal member in a U-shape so that the first resin member surrounds the back surface of the metal member. It is the form formed continuously.

  Next, the manufacturing method of the composite structure of this invention is demonstrated, referring FIGS.

  First, a metal member 13 having a desired shape is prepared. The metal member is preferably formed by die casting. Next, the metal member 13 is set in a mold (not shown) for insert molding. The cavity formed by the mold and the metal member 13 defines the shape of the first resin member.

  Next, molten resin is injected into the cavity formed by the mold and the metal member 13, and as shown in FIG. 2, the first resin member 12 a is formed at the joint portion (the end portion in this example) of the metal member 13. Is molded. In general, in insert molding, the mold is heated to an appropriate temperature. However, since the metal member 13 is usually set in a cold state (usually room temperature), the molten resin is injected in that state. The resin is rapidly cooled on the surface of the metal member, and the influence of the shrinkage difference is likely to occur, and the fluidity of the resin tends to deteriorate. Therefore, in the production method of the present invention, it is preferable to preheat the metal member to a temperature comparable to that of the mold (for example, within ± 10 ° C., preferably within ± 5 ° C.) before injecting the molten resin.

  Although the preheating temperature of the mold and the metal member depends on the type of the resin, it is usually about 60 to 120 ° C., preferably 70 to 100 ° C., particularly preferably 70 to 90 ° C. An example is 80 ° C.

  After cooling to a predetermined temperature, the mold is removed, and a composite structure (intermediate composite structure) in which the metal member 13 and the first resin member are integrated is taken out.

  Thereafter, after appropriately mounting the electronic component 11 and the like housed therein, as shown in FIG. 3, the mating surface of the second resin member 12b and the mating surface of the first resin member 12a separately formed in a desired shape, as shown in FIG. As shown in FIG. 4, the first resin member 12 a and the second resin member 12 b are integrated, and the composite structure 10 is obtained together with the metal member 13. Although welding of the 1st resin member 12a and the 2nd resin member 12b can be implemented with arbitrary welding techniques, such as laser welding and vibration welding, vibration welding is especially preferable from economical efficiency and simplicity.

  Further, when discarding, the composite structure is crushed with a crusher or the like, so that the resin and the metal are peeled off, so that an operation such as removing a bolt is unnecessary and can be easily separated. The sorted resin member can be recycled.

  The composite structural member of the present invention can be used for various applications in various forms and shapes. Particularly, it is suitable as a case for housing an electronic / electrical part that requires airtightness and emits heat, and includes, for example, an electronic control board casing, a battery casing, and a power control casing. In-vehicle applications such as In addition, it is suitable for applications where airtightness is required for joining metal and resin, for example, intake system parts such as intake manifolds, cooling system parts such as radiator pumps, fuel system parts such as fuel pumps, The present invention can be applied to automobile parts such as control system parts such as an ECU (Engine Computer Unit) housing, lubricating oil parts such as an oil pump, covers such as a cylinder head cover, and transmission parts.

<Measurement of linear expansion coefficient>
A test piece having a length of 20 mm, a width of 6 mm, and a thickness of 5 mm was produced using the resin to be measured. The test piece was measured for elongation in the range of −40 ° C. to 150 ° C. with a TMA apparatus (tensile mode, 2 g load, 5 ° C./min) while changing the temperature between −150 ° C. and 180 ° C. The same sample was measured twice and the second value was adopted. Moreover, about glass fiber reinforced nylon, the test piece was produced so that the direction of glass fiber might become a length direction.

<Example 1>
A 150 mm × 150 mm × 3 mm (thickness) die-cast aluminum plate was set in an insert molding die and preheated to 80 ° C., the same as the die. A molten resin of glass fiber reinforced nylon 6 is injected into a cavity formed by a mold and an aluminum plate, and an intermediate composite structure in which a resin member surrounds the aluminum plate from the front side to the back side as shown in FIG. 2 is manufactured. did. Here, the overlap between the aluminum plate and the resin was set to 6 mm around the aluminum plate. In addition, the flow direction at the time of injection | pouring of the glass fiber reinforced nylon 6 was controlled, and the resin member was shape | molded so that the direction of the glass fiber in a resin member might face the side substantially parallel in 4 sides of an aluminum plate.

  On the other hand, a lid member (having a shape similar to that of the second resin member 12b in FIG. 3) having a flange surface that coincides with the resin thus molded was molded using glass fiber reinforced nylon 6. The surface of the lid and the intermediate composite structure are put together and installed in a vibration welding apparatus, vibrated for 10 seconds at an amplitude of 1-2 mm and 240 Hz, and the mating surfaces are welded to form a sealed container-like composite structure. did.

The glass fiber reinforced nylon 6 resin used in Example 1 is obtained by adding 30 parts by weight of glass fiber to 70 parts by weight of nylon 6 and has a linear expansion coefficient of 2.4 × 10 ⁻⁵ cm / cm / ° C (range of 20 ° C to 150 ° C: glass fiber direction). The measurement result of the linear expansion coefficient is shown in FIG. The linear expansion coefficient of aluminum in the same temperature range is 2.4 × 10 ⁻⁵ cm / cm / ° C.

  Water pressure was applied from a nozzle-like hole provided in the lid material in order to investigate water tightness. Until the container broke at 0.6 MPa (gauge pressure), no leakage of water from the aluminum / resin joint was observed.

  Air pressure was applied through a nozzle-like hole provided in the lid to check the airtightness. Air leakage from the aluminum / resin joint was not observed until a slight leak occurred from the container at 0.4 MPa (gauge pressure) or higher.

<Comparative Example 1>
In Example 1, an intermediate composite structure having the same shape as in Example 1 was formed using nylon 6 containing no glass fiber. Using nylon 6, a lid material having the same shape as in Example 1 was molded, and the intermediate composite structure and the surface were combined to form an airtight container-shaped composite structure by vibration welding. The airtightness was examined in the same manner as in Example 1. As a result, air leaked from the joint between the aluminum and the resin, and the airtightness was insufficient. The linear expansion coefficient of nylon 6 used is 8.85 × 10 ⁻⁵ cm / cm / ° C. (range of 20 ° C. to 150 ° C.). The measurement result of the linear expansion coefficient is shown in FIG.

<Example 2: High temperature durability test, low temperature durability test, heat cycle test>
In the same manner as in Example 1, a plurality of sealed container-like composite structures were manufactured, and left in a predetermined environment for a predetermined time, and an environment resistance / durability test was performed. The test conditions are as follows.
High temperature test: left in a thermostatic bath at 150 ° C. for 750 hours or 1500 hours Low temperature test: left in a thermostatic bath at −40 ° C. for 750 hours or 1500 hours Heat cycle test: 2 hours under the condition of 150 ° C., −40 ° C. This was repeated 100 cycles with 2 hours as one cycle under the conditions.

  The evaluation was a pressure resistance test (water tightness test) and an air tightness test. In the pressure resistance test (water tightness test), water pressure was applied until breakdown as in Example 1, and the pressure at the time of breakdown was recorded. The results are shown in Table 1. In the air tightness test, air pressure of 0.15 MPa was applied to inspect for leaks. The results are shown in Table 2.

<Comparative Example 2: High temperature durability test, low temperature durability test, heat cycle test>
In Example 2, a composite structure was produced in the same manner using nylon 6 containing no glass fiber, and the environment resistance / durability test was similarly conducted. However, as shown in Tables 3 and 4, the time in the high temperature test and the low temperature test was 100 hours, and in the heat cycle test, it was 20 cycles. The evaluation method was also evaluated in the same manner as in Example 2. The results are shown in Tables 3 and 4.

  As described above, the composite structure of the present invention maintains pressure strength and airtightness even after a high temperature test, a low temperature test, and a heat cycle test, and is used in a harsh environment corresponding to such test conditions. It is clear that

  According to the present invention, it is possible to provide a composite structure in which the number of parts is small, the assembling time can be significantly shortened, and the airtightness at the joint surface between the metal and the resin is high.

DESCRIPTION OF SYMBOLS 10 Composite structure 11 Electronic component 12 Resin member 12a 1st resin member 12b 2nd resin member 13 Metal member 50 Storage case 53 Metal substrate 52 Resin case part 51 Electronic component 54 Bolt

Claims (13)

A composite structure having a sealed container-like structure formed by joining a metal member and a resin member,
The metal member is exposed on the inner side and the outer side of the sealed container-like structure,
The 1st resin member which exists in the location joined with the metal member is formed by injection molding surrounding the circumference of the metal member, and the linear expansion coefficient of the 1st resin member is 20 ° C-150 ° C The composite structure according to claim 1, wherein the composite structure has a range of 0.5 to 1.5 times the linear expansion coefficient of the metal member. The composite structure according to claim 1, wherein the metal member and the first resin member are fitted. The first resin member is formed continuously from the inner side to the outer side of the sealed container-like structure of the metal member so as to surround an end of the metal member in a U-shape. The composite structure according to claim 2. The said metal member is plate shape, The composite structure of any one of Claims 1-3 characterized by the above-mentioned. The said 1st resin member contains a resin component and an inorganic filler component, and the quantity of the said inorganic filler component is selected so that it may have the linear expansion coefficient of the said range , Any one of Claims 1-4 characterized by the above-mentioned. The composite structure according to claim 1 . 6. The composite structure according to claim 5 , wherein the inorganic filler is glass fiber or carbon fiber. The composite structure according to claim 5, wherein at least the resin component constituting the first resin member is a polyamide resin. The composite structure according to any one of claims 1 to 7 , wherein the metal member is aluminum processed by die casting. A method of manufacturing a composite structure having a sealed container-like structure in which a metal member and a resin member are joined at a joint,
Installing the metal member in a mold for insert molding;
A molten first resin member is poured into the mold, the metal member and the first resin member are joined at a joint, and the first resin member surrounds the first metal member . A step of molding a resin member;
A first resin member molded by bonding to the bonding portion and a second resin member formed in advance are welded so that the metal member is exposed to the inner side and the outer side of the sealed container-like structure, Forming the sealed container-like structure; and
In the range of 20 ° C. to 150 ° C., the first resin member has a linear expansion coefficient in the range of 0.5 to 1.5 times the linear expansion coefficient of the metal member. Method. The method for manufacturing a composite structure according to claim 9, wherein the metal member and the resin member are fitted in the step of molding the first resin member. The first resin member is formed continuously from the inner side to the outer side of the sealed container-like structure of the metal member so as to surround an end of the metal member in a U-shape. The method for producing a composite structure according to claim 10. The method for producing a composite structure according to any one of claims 9 to 11, wherein the metal member has a plate shape. 13. The composite according to claim 9 , wherein when the molten first resin member is injected, the metal member is preheated to substantially the same temperature as the mold. Manufacturing method of structure.

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