JP2010045077A - Cooling device, and designing method for cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device that efficiently cools a housing inexpensively by using a heat sink having a plurality of thin-plate fins joined to one surface of a base plate without using another means such as a heat pipe, and to provide a designing method for the cooling device. <P>SOLUTION: The cooling device includes: a fan which takes air in from one side of the housing in which a heat generating component is disposed and discharges it to the other, and also includes PQ characteristics within a predetermined range; and the heat sink having the plurality of thin-plate fins, with a fin pitch and a thickness corresponding to the PQ characteristics, on one surface of the base plate. The predetermined range of the PQ characteristics includes correlation with the thickness and fin pitch of the thin-plate fins, and is an area wherein thermal resistance is smaller as the fin pitch is larger as compared with a case wherein thin-plate fins having a predetermined thickness have a narrow fin pitch. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device for cooling a heat-generating component disposed inside a housing, and more particularly, a cooling device in which the thickness and fin pitch of a thin plate fin of a heat sink are set corresponding to a predetermined PQ characteristic of a fan, and The present invention relates to a method for designing a cooling device.

  There is a need for a high-performance heat sink with excellent heat dissipation efficiency due to an increase in heat generation amount and heat generation density of CPUs and elements. In order to cool the heat generating components arranged inside the housing, a fan for taking air from one side into the housing and exhausting from the other is provided at one end of the housing. A heat sink that is thermally connected to the heat-generating component is disposed.

  Conventionally, heat sinks made of extruded aluminum material, which are inexpensive to manufacture, have been used. The heat sink made of extruded material is easy to manufacture because the base plate and the heat radiating fin are integrally formed. However, the fin pitch is limited due to manufacturing limitations, and it is technically necessary to form the fin at a fine pitch. It was difficult.

  In order to reduce the fin pitch, a heat sink has been proposed in which a thin fin is joined to one surface of a base plate with solder or the like. Furthermore, a heat sink has been proposed in which a groove portion is provided on one surface of the base plate, a thin plate fin is inserted into the groove portion, and the thin plate fin is mechanically caulked and fixed (see Japanese Patent Laid-Open No. 2003-158227). By using these heat sinks, a large number of thin fins can be bonded to the base plate with a small fin pitch.

Furthermore, two types of metal with different thermal conductivities are used to make heat dissipation fins, heat dissipating fins made of metal with high thermal conductivity are placed near heat-generating elements such as semiconductor chips, and other parts. Has proposed a heat sink in which heat dissipating fins made of a metal having relatively low thermal conductivity are arranged (see JP 2002-237555 A).
JP 2003-158227 A JP 2002-237555 A

  As described above, a heat sink in which a fin pitch is small and a large number of thin plate fins are joined to a base plate is widely used. However, in practice, a large number of thin plate fins may be arranged on the base plate by reducing the fin pitch. However, the desired cooling cannot be obtained, and heat pipes are thermally connected to the base plate of the heat sink to take heat away. However, the cooling device is also required to improve performance at a low cost. If another means such as a heat pipe is attached, the cost of the entire cooling device increases.

  Accordingly, an object of the present invention is to efficiently cool a housing at a low cost by using a heat sink in which a plurality of thin plate fins are bonded to one surface of a base plate without using another means such as a heat pipe. It is an object of the present invention to provide a cooling device and a cooling device design method that can be used.

  The inventor has intensively studied to solve the above-mentioned conventional problems. As a result, if the fin pitch of the thin plate fins is reduced, the heat exchange area increases, but after a certain amount, the pressure loss of the air flow passing between the fins increases and the thermal resistance increases, conversely. When the fin pitch of the thin fins is increased, the heat exchange area is reduced, but the air volume is increased, and it has been found that the thermal resistance can be improved in a certain region.

  Further, when the PQ (static pressure / air volume) characteristics of the fan attached to the housing are within a predetermined range, a plurality of thin plate fins having fin pitches and thicknesses corresponding to the PQ (static pressure / air volume) characteristics are provided as base plates. It has been found that a high cooling effect can be obtained by using a heat sink provided on one of the surfaces. The present invention has been made based on the above-described results.

According to a first aspect of the cooling device of the present invention, a fan having a PQ characteristic within a predetermined range that takes in air from one of housings in which heat-generating components are arranged and exhausts the air to the other,
The cooling device includes a heat sink having a plurality of thin plate fins having fin pitches and thicknesses corresponding to the PQ characteristics on one surface of the base plate.

  According to a second aspect of the cooling device of the present invention, the predetermined range of the PQ characteristic has a correlation with the thickness and fin pitch of the thin plate fin, and the fin pitch of the thin plate fin with the predetermined thickness is narrow. The cooling device is a region in which the heat resistance is smaller when the fin pitch is larger than that.

  According to a third aspect of the cooling apparatus of the present invention, the predetermined range of the PQ characteristic is an approximate straight line of the PQ characteristic when the pressure loss (Pa) is taken on the vertical axis and the wind speed (m / s) is taken on the horizontal axis. The cooling device has an inclination of −0.6 or more.

  According to a fourth aspect of the cooling device of the present invention, the predetermined thickness of the thin plate fin is in a range of 0.1 to 0.5 mm, and the fin pitch is in a range of 2.0 to 3.5 mm. It is a cooling device.

  According to a fifth aspect of the cooling device of the present invention, the predetermined thickness of the thin plate fin is within a range of 0.1 to 0.3 mm, and the fin pitch is within a range of 2.5 to 3.5 mm. It is a cooling device.

  The 6th aspect of the cooling device of this invention is a cooling device in which the said thin-plate fin is a fin formed by arrange | positioning the substantially U-shaped thin plate in parallel.

  According to a seventh aspect of the cooling device of the present invention, the thin plate fin is a fin that is inserted into a groove portion formed on one surface of the base plate, and both sides of the groove portion are fixed by plastic deformation. It is.

According to a first aspect of the cooling device design method of the present invention, a fan having a PQ characteristic within a predetermined range is prepared.
The cooling device design method includes preparing a heat sink including a base plate and a plurality of thin plate fins based on the fin pitch and thickness corresponding to the PQ characteristics.

  According to a second aspect of the cooling device design method of the present invention, the predetermined range of the PQ characteristics is greater when the fin pitch of the thin plate fin of the predetermined thickness is larger than that when the fin pitch is larger. This is a method for designing a cooling device, which is set in a region where the value becomes small.

  According to the present invention, the housing can be efficiently cooled at a low cost by using a heat sink in which a plurality of thin plate fins are bonded to one surface of the base plate without using another means such as a heat pipe. A cooling device and a method for designing the cooling device can be provided. According to the present invention, since the fin thickness and fin pitch are determined in accordance with the desired PQ characteristics, an appropriate air volume can be flowed between the thin plate fins without flowing a wasteful air volume, thereby effectively reducing the thermal resistance. Can be small.

A cooling device and a cooling device design method according to the present invention will be described with reference to the drawings.
One aspect of the cooling device of the present invention is a fan having a PQ characteristic within a predetermined range that takes in air from one of the casings in which the heat generating components are arranged, and exhausts the air to the other. The cooling device includes a heat sink provided with a plurality of thin plate fins having corresponding fin pitches and thicknesses on one surface of the base plate.

The above-mentioned predetermined range of the PQ characteristic has a correlation with the thickness and fin pitch of the thin plate fin, and the thermal resistance is larger when the fin pitch is larger than when the fin pitch of the thin plate fin of the predetermined thickness is narrow. Is a region where becomes smaller.
More specifically, the predetermined range of the PQ characteristic described above is such that the slope of the approximate line of the PQ characteristic when the pressure loss (Pa) is taken on the vertical axis and the wind speed (m / s) is taken on the horizontal axis is −0. 6 or more (inclination decreases with respect to the vertical axis).

  In other words, in the present invention, the fin pitch is reduced on the base plate, and as many thin plate fins as possible are formed on the base plate as much as possible. Conversely, there is a region where the thermal resistance is small (so-called thermal performance reversal region), and the fin pitch is set in this region. As a result, it is based on the idea that an appropriate amount of wind can flow between the fins to efficiently dissipate heat. The size of the fin pitch described above corresponds to the thickness of the thin plate fin and the PQ characteristics of the fan used.

A preferable range of the PQ characteristic that enables the so-called reverse region of the thermal performance described above, and the fin pitch and thickness corresponding to the PQ characteristic will be described below.
FIG. 1 is a graph showing the relationship between the PQ characteristics of a fan and the impedance in the housing (heat sink). FIG. 1 shows three types of PQ characteristics (indicated by X, Y, and Z). Three cases of A, B, and C are shown as the impedance of the heat sink. The fin pitch of the heat sink increases in the order of A, B, and C.
The specifications of the fan to be used are determined by the heat (power consumption) generated in the housing, so the PQ characteristics are uniformly determined. In the PQ characteristics shown in the figure, the inclination decreases in the order of X, Y, and Z.

A PQ characteristic indicated by X is a PQ characteristic of a fan used in a conventionally used heat sink. In the PQ characteristics of a fan used in a conventional heat sink, the air volume is small in any of three cases of A, B, and C as the impedance of the heat sink, and a desired air volume cannot be obtained.
In the case of the PQ characteristic having a smaller slope than the PQ characteristic indicated by X, the thermal resistance can be reduced by obtaining a desired air volume even if the fin pitch is increased. Therefore, a fan having a PQ characteristic whose inclination is smaller than the PQ characteristic indicated by X is required.

  FIG. 2 shows various fin numbers when a fan having a PQ characteristic with a small inclination is used. It is a graph which shows the relationship between the fin pitch of 1-7, a wind speed, and a pressure loss. The PQ characteristics of the fan shown in FIG. 2 are a maximum static pressure of 6 Pa and a maximum wind speed of 3.3 m / s. No. 1 to 4 are fins in which generally U-shaped fins are arranged in parallel and one surface forms a heat receiving surface as a whole.

  Each of these fins has a thickness of 0.3 mm. No. The fin No. 1 has a fin pitch of 1.5 mm and No. 1 fin. The fin No. 2 has a fin pitch of 2.5 mm, No. 3 fin has a fin pitch of 3 mm, No. 3 fin. The fin 4 has a fin pitch of 3.5 mm. In contrast, no. Fins 5 to 7 are fins formed by extrusion. Each of these fins has a thickness of 0.5 mm. No. The fin No. 5 has a fin pitch of 2 mm, The fin No. 6 has a fin pitch of 2.5 mm, The fin No. 7 has a fin pitch of 3 mm.

  As shown in FIG. 2, when the fin pitch is reduced, the air volume (wind speed) is reduced and the pressure loss is increased. This is no. 1 No. 1 by extrusion molding. Notable with 5 fins. No. by extrusion molding For the fin No. 6, the fin pitch is large, but the pressure loss is still high. On the other hand, when the fin pitch is increased, no. 2, No. 3, no. No. 4 fin and No. by extrusion molding. As shown by the fin 7, the air volume (wind speed) is increased and the pressure loss is reduced.

  3 shows various fin numbers shown in FIG. It is a graph which shows the relationship between the air volume (wind speed m / s) of 1 to 7, and thermal resistance (degreeC / w). As shown in the graph of FIG. 3, No. 1 having a thickness of 0.3 mm and a fin pitch of 1.5 mm. The fin 1 has an air volume (wind speed m / s) as small as 0.5 or less and has a very large thermal resistance. In addition, No. by extrusion molding with a thickness of 0.5 mm and a fin pitch of 2 mm. Similarly, the fin No. 5 has an air volume (wind speed m / s) as small as 0.5 or less, and has a very large thermal resistance.

  On the other hand, No. 1 having a thickness of 0.3 mm and a fin pitch of 2.5 mm. No. 2 fin having a thickness of 0.3 mm and a fin pitch of 3 mm. No. 3 fin having a thickness of 0.3 mm and a fin pitch of 3.5 mm. Each of the fins 4 has an air volume (wind speed m / s) in the range of 1 to 1.5 and a low thermal resistance.

  As is clear from the above description, when a fan having PQ characteristics within a predetermined range (small inclination shown in FIG. 1) is used, the thermal resistance is larger when the fin pitch is larger than when the fin pitch is narrow. There is a region where so becomes small (so-called thermal performance reversal region).

  As described above, the predetermined range of the PQ characteristic is that the slope of the approximate straight line of the PQ characteristic when the pressure loss (Pa) is taken on the vertical axis and the wind speed (m / s) is taken on the horizontal axis is −0.6 or more. Yes (the slope is smaller with respect to the vertical axis).

  Corresponding to the PQ characteristics described above, the thickness and fin pitch of the thin plate fins are set. A preferable thickness of the thin plate fin is in a range of 0.1 to 0.5 mm, and a fin pitch is in a range of 2.0 to 3.5 mm. More preferably, the thickness of the thin plate fin is in the range of 0.1 to 0.3 mm, and the fin pitch is in the range of 2.5 to 3.5 mm.

The thin plate fin may have any shape, but a fin formed by arranging generally U-shaped thin plates in parallel is preferable in that a thin plate fin having a desired thickness can be used. In addition, a so-called crimp fin in which a thin plate fin is inserted into a groove portion formed on one surface of the base plate and both side portions of the groove portion are fixed by plastic deformation may be used.
A fan having a desired PQ characteristic is used. As for the PQ characteristics of the axial fan, the maximum static pressure does not change by arranging n fans in parallel, but the maximum air volume (wind speed) is increased by a factor of n. ) Fans may be arranged in parallel.

  As described above, according to the present invention, the housing can be efficiently manufactured at low cost by using a heat sink in which a plurality of thin plate fins are bonded to one surface of the base plate without using another means such as a heat pipe. It is possible to provide a cooling device that can be cooled and a method for designing the cooling device.

FIG. 1 is a graph showing the relationship between the PQ characteristics of a fan and the impedance in the housing (heat sink). FIG. 2 shows various fin numbers when a fan having a PQ characteristic with a small inclination is used. It is a graph which shows the relationship between the fin pitch of 1-7, a wind speed, and a pressure loss. 3 shows various fin numbers shown in FIG. It is a graph which shows the relationship between the air volume (wind speed m / s) of 1 to 7, and thermal resistance (degreeC / w). FIG. 4 is a table showing thermal resistance, wind speed, pressure loss, and slope of PQ characteristics when the fin pitch is 2.5 mm and 3.0 mm.

Claims (9)

A fan having a PQ characteristic within a predetermined range that takes in air from one of the housings in which the heat generating components are arranged and exhausts the air to the other;
A cooling device comprising: a heat sink provided with a plurality of thin plate fins having fin pitches and thicknesses corresponding to the PQ characteristics on one surface of a base plate.   The predetermined range of the PQ characteristic has a correlation with the thickness and fin pitch of the thin fins, and the thermal resistance is larger when the fin pitch is larger than when the fin pitch of the thin fins with the predetermined thickness is narrow. The cooling device according to claim 1, wherein the cooling region is a region in which becomes small.   The predetermined range of the PQ characteristic is such that the slope of the approximate straight line of the PQ characteristic is −0.6 or more when the pressure loss (Pa) is taken on the vertical axis and the wind speed (m / s) is taken on the horizontal axis. Item 3. The cooling device according to Item 2.   The predetermined thickness of the thin plate fin is within a range of 0.1 to 0.5 mm, and the fin pitch is within a range of 2.0 to 3.5 mm. The cooling device according to item.   The cooling device according to claim 4, wherein the predetermined thickness of the thin plate fin is in a range of 0.1 to 0.3 mm, and the fin pitch is in a range of 2.5 to 3.5 mm.   The cooling device according to any one of claims 1 to 5, wherein the thin plate fins are fins formed by arranging substantially U-shaped thin plates in parallel.   The cooling according to any one of claims 1 to 5, wherein the thin plate fin is a fin that is inserted into a groove portion formed on one surface of the base plate, and both side portions of the groove portion are fixed by plastic deformation. apparatus. Preparing a fan having a PQ characteristic within a predetermined range;
A cooling device design method for preparing a heat sink composed of a base plate and a plurality of thin plate fins based on a fin pitch and a thickness corresponding to the PQ characteristics. 9. The cooling according to claim 8, wherein the predetermined range of the PQ characteristic is set in a region where the thermal resistance is smaller when the fin pitch is larger than when the fin pitch of the thin plate fin of the predetermined thickness is narrow. Device design method.

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