JP2010201497A - Heat sink for strong electric car parts, heat sink unit using the same, and method for producing heat sink for strong electric car parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sink for strong electric car parts made of a stock provided with high thermal conductivity, sufficient mechanical strength and satisfactory castability, and having high heat dissipation efficiency, to provide a heat sink unit using the same, and to provide a method for producing the heat sink for strong electric car parts. <P>SOLUTION: The heat sink for strong electric car parts made of aluminum is provided with: a cooling passage; a contact part of a heat source; and a heat dissipation fin projected from the back face part of the contact part, wherein the back face part composes a part of the cooling passage. The aluminum alloy has a composition comprising Si, Mg and Fe, and the balance aluminum with inevitable impurities, and has the characteristics satisfying the thermal conductivity of 150 to 200 W/mK and the hardness of 38 to 100 HRF, and in which the heat dissipation area of the back face corresponding to the contact face between a heat source and the back face corresponding to the contact face of the contact part is 3 to 20 times the area of the contact face. The heat sink unit includes: the heat sink for strong electric car parts ; and a heat source. In the method for producing the heat sink for strong electric car parts, after the heat dissipation fin is integrally molded by a die casting process, aging treatment is performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat sink (cooler) for automotive high-power components for cooling a heat source, a heat sink unit using the same, and a manufacturing method thereof, and more particularly, excellent thermal conductivity, mechanical strength and casting. TECHNICAL FIELD The present invention relates to a heat sink for an automotive high-voltage component made of an aluminum alloy having high heat dissipation efficiency, a heat sink unit using the heat sink, and a manufacturing method thereof.

  In semiconductor devices, particularly semiconductor devices such as inverters that convert DC power into AC power and converters that convert AC power into DC power, the amount of heat generated increases as power consumption increases and the size of the device decreases. High heat dissipation efficiency is required for a heat sink for cooling the apparatus.

  Therefore, conventionally, the shape of the radiating fin portion in contact with the cooling medium such as water or air is made finer and complicated to increase the heat radiating surface of the heat sink, or the alloy components and heat treatment methods that are the materials of the heat sink are optimized. Attempts have been made to improve the heat dissipation efficiency of the heat sink by increasing the thermal conductivity of the heat sink.

  For example, as a general high thermal conductive material, pure aluminum (thermal conductivity: 220 W / mK) can be cited. Some high thermal conductive aluminum alloys have been proposed (see Patent Document 1, Patent Document 2 and Patent Document 3).

JP 2005-290527 A JP 2005-298856 A JP 2006-63420 A

  In addition, the heat sink material is required to have mechanical strength against screwing to be attached to a semiconductor to be cooled or bulge press-fitting of water or the like as a cooling medium. Since castability (moldability) for molding at low cost without requiring labor is also required, for example, die casting materials such as ADC12, which is a material excellent in mechanical strength and castability, are used for the radiation fins. .

  However, the thermal conductivity and mechanical strength of the material are contradictory properties, and the mechanical strength of the above pure aluminum and high thermal conductivity aluminum alloy is low, and the high thermal conductivity is mechanical strength that can withstand bulge press-fitting etc. Incompatible with. The ADC 12 described above is excellent in mechanical strength and castability, but has low thermal conductivity and poor heat dissipation efficiency.

  That is, in such a conventional technique, there is no suitable material having high thermal conductivity, sufficient mechanical strength, and good castability, and therefore it is difficult to manufacture a heat sink having desirable heat dissipation efficiency. There was a problem of being.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is a heat sink with high heat dissipation efficiency, particularly high heat conductivity, sufficient mechanical strength, and a large amount. An object of the present invention is to provide a heat sink for automobile high-power components with high heat dissipation efficiency, which is made of a material having castability suitable for production, a heat sink unit using the heat sink, and a manufacturing method thereof.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by appropriately controlling the heat radiation area of a predetermined part using an aluminum alloy having a specific component ratio. The headline and the present invention were completed.

  That is, the heat sink for automotive high-power components of the present invention has a cooling passage through which a cooling medium circulates, a contact portion that comes into contact with a heat source, and a heat radiation fin that protrudes integrally from the back surface portion of the contact portion. The back surface portion with fins is made of an aluminum alloy having a structure constituting a part of the refrigerant passage. The aluminum alloy is composed of Si, Mg, Fe, the balance aluminum, and unavoidable impurities, and has characteristics of thermal conductivity of 150 to 200 W / mK and hardness of 38 to 100 HRF, and further, the heat source and the above The heat radiation area on the back surface corresponding to the contact surface with the contact portion is 3 to 20 times the area of the contact surface. The heat sink unit of the present invention is characterized by having the heat sink for automotive high-power components and the high-power automotive component as a heat source.

  Moreover, the manufacturing method of the heat sink for automotive high-power components according to the present invention is a manufacturing method of the heat sink for automotive high-power components as described above, and the aging fin is subjected to aging treatment after the heat radiation fin is integrally formed by the die casting method. Features.

  According to the present invention, an aluminum alloy having specific components and characteristics is used to appropriately control the heat radiation area of a predetermined portion, so that it is suitable for high thermal conductivity, sufficient mechanical strength, and mass production. It is possible to provide a heat sink for automobile high-power components with high heat dissipation efficiency, a heat sink unit using the same, and a method of manufacturing the same.

It is a notch top view which shows one Embodiment of the heat sink unit using the heat sink for motor vehicle electrical components of this invention. It is sectional drawing in the II-II cross section of the heat sink unit shown in FIG. It is the schematic of the shell sand spiral type for molten metal flow length evaluation. It is explanatory drawing of the thermal radiation efficiency measuring method.

  Hereinafter, an embodiment of a heat sink and a heat sink unit for an automotive high power component according to the present invention will be described in detail with reference to the drawings. In the present specification, “%” for concentration, content, blending amount and the like represents a mass percentage unless otherwise specified.

  FIG. 1 is a cutaway plan view showing an embodiment of a heat sink unit of the present invention. FIG. 2 is a cross-sectional view of the heat sink unit shown in FIG. This heat sink unit is composed of a heat sink 200 for automobile high-power components, which is an embodiment of a heat sink for automotive high-power components of the present invention, and a heat source 100.

(1) Heat sink for automotive high-power components In FIG. 2, a heat sink for automotive high-power components 200 is integrated from a cooling passage 10 through which a cooling medium flows, a contact portion 20 in contact with the heat source 100, and a back surface portion 22 of this contact portion. And a heat radiation fin 30 protruding in the direction. And this back surface part 22 with a radiation fin comprises a part of said cooling channel | path 10. FIG.
Note that this heat sink for high-voltage automotive components is made of an aluminum alloy described later.

  The heat source 100 is an object to be cooled by the heat sink for automotive high-power components of the present embodiment, and is a high-power automotive component such as an inverter, a motor, a converter, and a capacitor. The entire area where the heat source 100 and the contact portion 20 of the heat sink for automobile high-power components are in contact is referred to as a contact surface 21. This contact surface 21 is naturally included in the contact portion 20.

  Further, a surface corresponding to the entire range vertically lowered from the entire range of the contact surface 21 toward the back surface portion 22 is referred to as a “back surface 23 corresponding to the contact surface”. Naturally, this back surface 23 has the same area as the contact surface 21. And since this back surface 23 is a part or all of the back surface part 22, it has the radiation fin which protruded integrally, and the whole surface of the fin 31 projected in the range of this back surface 23, and parts other than a fin The total surface area of the back surface 23 is referred to as the “heat dissipating area” of the back surface 23 corresponding to the contact surface 21.

  In the heat sink for automotive high-power components of the present invention, the heat dissipation area is 3 to 20 times the area of the contact surface. If it is less than 3 times, the heat dissipation efficiency of the heat sink for automotive high-voltage parts is significantly lowered and the desired performance cannot be obtained. On the other hand, if it exceeds 20 times, the shape of the heat dissipation fin becomes very complicated, making it difficult to mold. . In particular, when manufacturing the heat sink for automotive high-power components of this embodiment, in order to mass-produce at a low cost, for example, the heat radiation fin is integrally formed by die casting, so that it is difficult to mold the heat radiation fin having a complicated shape. .

In the present invention, the aluminum alloy constituting the heat sink for automotive high-voltage components having the above-described structure is composed of Si, Mg, Fe, the balance aluminum, and inevitable impurities, and has a thermal conductivity of 150 to 200 W. / mK and hardness of 38 to 100 HRF. Of these, an aluminum alloy having a thermal conductivity of 160 to 200 W / mK is preferable. If the thermal conductivity is less than 150 W / mK, the target heat dissipation efficiency cannot be obtained, and if it exceeds 200 W / mK, the mechanical strength decreases. Also, if the hardness is less than 38 HRF, it cannot withstand threading or sag or cooling water bulge injection when assembling a semiconductor device (heat source), and if it exceeds 100 HRF, the thermal conductivity decreases and is less than 150 W / mK. Become.
The aluminum alloy having these components and characteristics realizes a heat sink for automobile high-power components having high heat dissipation efficiency due to the characteristics of thermal conductivity and mechanical strength. Moreover, it is possible to implement | achieve the value regarding the castability shown below.

  About the said castability, although the value which compared the molten metal flow length with the aluminum alloy ADC12 is used as the parameter | index, it is preferable that the value is 60 to 90%. If it is less than 60%, a fin having a desired heat radiation area may not be integrally formed by a die casting method.

Next, each component of the aluminum alloy, that is, Si, Mg, Fe, inevitable impurities, etc. will be described in detail.
As described above, the aluminum alloy contains Si, Mg, and Fe, but the preferable content ratio is 5.0 to 10.0 mass% for Si and 0.1 to 0.5 mass% for Mg. Fe is 0.3-0.6% by mass, more preferably Si is 6.0-9.0% by mass, Mg is 0.1-0.4% by mass, and Fe is 0.3-0. 6% by mass.

In the present invention, since Si has an effect of improving castability, when an aluminum alloy having a content of less than 5.0% is used, a heat sink for an automotive high-voltage component having a heat radiation fin having a complicated shape or a thin portion. In particular, the production of such products tends to be difficult. In addition, Si also has the effect of improving the mechanical strength, wear resistance and vibration proofing properties of the aluminum alloy.
On the other hand, when the Si content is increased, the thermal conductivity of the aluminum alloy is lowered. Therefore, if the content exceeds 10%, a desired thermal conductivity may not be obtained. Excessive Si also tends to reduce the extensibility of the aluminum alloy.

  Mg, when the aging treatment described later is performed at the time of manufacturing a heat sink for automobile high-power components, Si in the aluminum matrix phase is precipitated as an Mg-Si compound to reduce the amount of Si solid solution in the matrix phase, It has the effect of improving conductivity. Moreover, the mechanical strength of an aluminum alloy improves by containing Mg. These effects tend to be prominent when the Mg content is 0.1% or more, and when it exceeds 0.5%, the thermal conductivity tends to decrease.

Fe improves the mechanical strength and has the effect of preventing die seizure when cast by the die casting method. These effects become significant when the content is 0.3% or more. There is a tendency.
On the other hand, when the Fe content is increased, the thermal conductivity and the extension rate of the aluminum alloy are decreased. Therefore, when the content exceeds 0.6%, the thermal conductivity tends to be decreased.

  The inevitable impurities lower the thermal conductivity of the aluminum alloy as its content increases. Therefore, the total content is preferably suppressed to 0.5% or less. In particular, it is preferable to keep the total of transition elements such as Ti, Mn and Cr having a relatively small solid solubility limit in the aluminum matrix to 0.1% or less.

  Further, the Si solid solution amount of the aluminum alloy in the aluminum matrix is preferably 0.50% by mass or less, the Mg solid solution amount is preferably 0.20% by mass or less, and more preferably the Si solid solution amount is 0%. 20% by mass or less, and Mg solid solution amount is 0.10% by mass or less. It is because more suitable thermal conductivity can be ensured.

(2) Heat Sink Unit As shown in FIG. 2, the heat sink unit of the present invention has a heat sink 200 for an automotive high voltage component and a heat source 100. Moreover, it is preferable that the heat source 100 is provided in contact with the heat sink 200 for automobile high-voltage components.
As described above, the heat source is a high-voltage automotive component such as an inverter, a motor, a converter, and a capacitor.

Next, an embodiment of a method for manufacturing a heat sink for automotive high-voltage components of the present invention will be described.
This manufacturing method is a method for manufacturing a heat sink for an automotive high-voltage component as described above, using the aluminum alloy having the specific component ratio described above as a material, and then integrally molding the above-described heat radiation fin by a die casting method, Aging treatment is performed.

  Here, the die casting method is a method of molding by pouring molten metal into a mold. Depending on the filling pressure of the molten metal, gravity casting method, low pressure casting method, high pressure casting method, squeeze die casting method (laminar flow filling die casting method), etc. Among them, among them, the high pressure casting method is preferable because it is inexpensive and has high mass productivity.

  After molding by the die casting method, aging treatment can be performed to precipitate solid solution elements in the matrix of aluminum and improve the thermal conductivity. The temperature of the heat treatment is preferably 270 ° C to 380 ° C, more preferably 300 ° C to 350 ° C. If the temperature is lower than 270 ° C., the effect of improving the thermal conductivity may be reduced. If the temperature exceeds 350 ° C., blistering starting from voids that may occur at the time of molding (casting) occurs and the mechanical strength decreases. Because there is a possibility of doing. The processing time is a general aging time, for example, 2 to 12 hours.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

(Examples 1-13, Comparative Examples 1-3)
Aluminum alloys having the respective component ratios and characteristics shown in Table 1 were melted, and the heat sink for automotive high-voltage components shown in FIGS. 1 and 2 was manufactured by a die casting method. The heat sinks for automotive high-power components obtained in each example were subjected to aging treatment (300 ° C.), and then the thermal conductivity (laser flash method) and hardness (HRF: F scale of Rockwell hardness) by the measurement method described later. ) Was measured before and after aging treatment. The results are shown in Table 1.

  Table 2 shows whether or not die casting moldability is possible when manufacturing the heat sink for automotive high-power components described above. Moreover, about each of these aluminum alloys, the melt flow length (comparison with ADC12 alloy) was measured by the melt flow length measurement method described later, and the results are shown in Table 2.

From Table 2, in the comparative example using the aluminum alloy which does not contain Si of an alloy component, die casting was not able to be performed.
Moreover, the thing with a low value of thermal conductivity did not obtain a favorable result also in the molten metal flow length (ADC12 alloy ratio).

  In order to obtain a high thermal conductivity, an aluminum alloy containing no elements other than Si, Mg and Fe is desirable, Cu: 0.1% or less, Mn: 0.05% or less, Cr: 0 The thermal conductivity was good even when the content of Ti was 0.05% or less, and the results of die casting moldability and molten metal flow length were also good.

(Example 14, Comparative Examples 4 and 5)
Using the aluminum alloy shown in Table 3 (see Table 1 for the component ratio and characteristics), three types of heat sinks for high-voltage automotive parts with different heat dissipation areas on the back surface corresponding to the contact area with the heat source (heater) are produced by die casting. Molded integrally. Then, using water as a cooling medium, the heat dissipation efficiency of these heat sinks for high-voltage automotive components was evaluated. Table 3 shows the evaluation results of the shape and heat dissipation efficiency of the heat sinks for each automotive high-voltage component.

  From Table 3, it can be seen that the heat sink for automotive high-power components having a heat dissipation area ratio of less than 3 times (Comparative Example 4) has low heat dissipation efficiency and cannot function as a heat sink for automotive high-power components. Moreover, the heat sink for automobile high-power components having a heat dissipation area ratio exceeding 20 times (Comparative Example 5) could not mold the fin portion.

(Examples 15 to 19, Comparative Examples 6 and 7)
Using the alloys shown in Table 1 (Alloy Nos. 1, 4 and 9 (see Table 1)), the aging treatment temperature and time after integral molding by the die casting method were changed, and the thermal conductivity and hardness before and after the aging treatment were changed. The solid solution amount after aging treatment was measured. Table 4 shows the aging treatment conditions and the measurement results.

  From Table 4, it can be seen that when the thermal conductivity or hardness after the aging treatment does not satisfy the condition, the Si solid solution amount becomes relatively large or molding failure occurs.

[Measuring method]
The performance measurement methods used in the above examples and comparative examples will be described below.
(A) Melt Flow Length Evaluation of the melt flow length of the present invention was performed by a method using a shell sand spiral type shown in FIG. That is, the molten metal flow length was measured when a predetermined composition of molten metal at 700 ° C. was poured from a predetermined position into a cavity constituted by a shell sand like a mosquito coil.

(B) Thermal conductivity The thermal conductivity of the present invention was evaluated by a laser flash method. That is, a laser beam is emitted from a laser oscillator, directly applied to the surface of the sample, the amount of heat emitted from the back surface of the sample and its time are measured, and the specific heat (Cp) and the thermal diffusivity (α) are derived. ) To calculate the thermal conductivity (λ).
・ Thermal conductivity: λ = α ・ Cp ・ ρ (1)
(Ρ: Sample density)
The thermal diffusivity α was calculated from the t1 / 2 (time to reach 1/2 of the maximum temperature rise ΔTm) and the thickness L using the formula (2).
.Alpha. = 0.1388L2 / t1 / 2 (2)

(C) Hardness The hardness evaluation of the present invention was performed by the Rockwell hardness test. The evaluation of hardness is based on the point at which the initial test force is applied as the zero point of the depth. Further, after applying the test force, it is returned to the initial test force again, and the depth of the indentation at the initial test force twice before and after that The difference h (mm) was measured to calculate the hardness value.

(D) Solid solution amount The solid solution amount in the aluminum matrix of the present invention was measured by dissolving the aluminum matrix by the hot butanol method and quantifying the target element in the solution by the atomic absorption method.

(E) Heat dissipation efficiency As shown in FIG. 4, the heat dissipation efficiency of the present invention was obtained by measuring the heat source bottom surface temperature and the cooling medium temperature with a thermocouple, and calculating the heat dissipation efficiency from the difference between these measured values.

DESCRIPTION OF SYMBOLS 10 Cooling path 20 Contact part 21 Contact surface 22 Back surface part 23 Back surface corresponding to a contact surface 30 Radiation fin 31 Fin 100 protruded on the back surface corresponding to a contact surface Heat source 200 Heat sink for automotive high power components

Claims (11)

A cooling passage through which the cooling medium flows, a contact portion in contact with the heat source, and a radiation fin integrally protruding from the back surface portion of the contact portion, and the back surface portion with the radiation fin is a part of the refrigerant passage. A heat sink for an automotive high-voltage component made of an aluminum alloy having a structure comprising:
The aluminum alloy is composed of Si, Mg, Fe, the balance aluminum, and inevitable impurities, and has the characteristics of thermal conductivity of 150 to 200 W / mK and hardness of 38 to 100 HRF,
The heat radiation area on the back surface corresponding to the contact surface between the heat source and the contact portion is 3 to 20 times the area of the contact surface.
A heat sink for automotive high-voltage components.   2. The heat sink for an automotive high voltage component according to claim 1, wherein the thermal conductivity is 160 to 200 W / mK.   3. The automobile high voltage according to claim 1 or 2, wherein the amount of Si solid solution in the aluminum matrix of the aluminum alloy is 0.50% by mass or less and the amount of Mg solid solution is 0.20% by mass or less. Heat sink for parts. 3. The automobile high voltage according to claim 1, wherein the amount of Si solid solution in the aluminum matrix of the aluminum alloy is 0.20% by mass or less, and the amount of Mg solid solution is 0.10% by mass or less. Heat sink for parts.   5. The heat sink for an automotive high-voltage component according to claim 1, wherein the aluminum alloy has a molten metal flow length of 60 to 90% as compared with the ADC12 alloy.   The above aluminum alloy is unavoidable with 5.0 to 10.0% by mass of Si, 0.1 to 0.5% by mass of Mg, 0.3 to 0.6% by mass of Fe and the balance of aluminum. The heat sink for automobile high-voltage components according to any one of claims 1 to 5, characterized by comprising impurities. The aluminum alloy is inevitable with 6.0-9.0 mass% Si, 0.1-0.4 mass% Mg, 0.3-0.6 mass% Fe, the balance aluminum. The heat sink for automobile high-voltage components according to any one of claims 1 to 5, characterized by comprising impurities. A heat sink unit comprising the heat sink for an automotive high-voltage component according to any one of claims 1 to 7, and a heat source,
The heat source is a high-voltage automotive component.
A heat sink unit characterized by that. In manufacturing the heat sink for an automotive high voltage component according to any one of claims 1 to 7,
A method of manufacturing a heat sink for an automotive high-voltage component, characterized in that the heat radiating fin is integrally molded by a die casting method and then subjected to an aging treatment.   The method for producing a heat sink for an automotive high-voltage component according to claim 9, wherein the aging treatment temperature after die casting is 270 to 380 ° C.   The method for producing a heat sink for an automotive high-voltage component according to claim 9, wherein the aging treatment temperature after die casting is 300 to 350 ° C.

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