JPH11103183A - Heat sink device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a heat sink device possessed of a high heat dissipation function by a method, wherein heat dissipating fins are set suitably into shapes for boundary layer control. SOLUTION: Plural plate-like heat dissipating fins 2 provided upright to a base 1 are arranged in rows in a first direction which coincides with the direction of a cooling air flow. Each of the rows is composed of plate-like heat dissipating fins 2 and arranged in zigzags fashion. The upper or lower edge of one of the heat dissipating fins 2 located at a predetermined position is bent into a second or a third direction which forms a prescribed angle with the first direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink device, and more particularly, to a heat sink device which is constituted by radiation fins projecting from a base and realizes a high heat radiation function.

2. Description of the Related Art In recent years, in order to realize miniaturization and high performance of electronic devices, the integration degree of LSI devices, especially CPUs, has been dramatically increased and the operating frequency has been dramatically increased. It is going to. Along with this, the amount of heat generated tends to increase despite efforts to reduce the power of the circuit and the like, and an efficient heat radiating device is required. This L
Generally, a heat sink device is widely used as a heat radiating device for realizing efficient heat radiation of a high heat generating element such as an SI element.

[0003]

2. Description of the Related Art A heat sink device is made of a material having a high thermal conductivity such as aluminum or its alloy, copper or its alloy, and has a shape suitable for rapidly dissipating heat generated in an LSI. For example, a heat sink device
As shown in FIG. 10, a base 10 is fixed to the mounting surface of the high heat generating element, and a plurality of radiation fins 20 projecting from the base 10 in a substantially vertical direction. FIG.
The heat sink device shown in FIG. 0A has a pin-shaped heat radiation fin 20, and the heat sink device shown in FIG. 10B has a plate-shaped heat radiation fin 20. The heat sink device having such a structure radiates heat generated by the LSI from the radiating fins 20 into the air at high speed by using cooling air sent by a cooling fan or the like.

[0004]

In order to increase the heat radiation efficiency of the heat sink device, it is necessary to improve the heat transfer coefficient;
That is, it is necessary to increase the surface area of the radiation fin 20. For this reason, conventionally, the pitch between the heat radiation fins 20 has been narrowed, or the thickness of the heat radiation fins 20 itself has been reduced to increase the number of the heat radiation fins 20, thereby increasing the total heat radiation area.

However, the heat radiation efficiency of the heat sink device is
It is not determined only by the total surface area of the radiation fins 20, but the speed of the cooling air flowing between the radiation fins 20,
It is related to the flow condition. For example, the flow largely depends on the state in which the flow is separated from the radiating fins 20 (separated state) and the state of the thickness of the air boundary layer generated near the radiating fins 20.

When the number of the radiation fins 20 is increased, the air resistance (pressure loss) increases due to the denseness of the radiation fins 20. For this reason, the cooling air escapes to the upper part (vertical direction of the base body 10) avoiding the radiation fins 20 (peeling).
As a result, the speed and amount of the cooling air flowing between the radiation fins 20 decrease. This reduction in the speed and amount of the cooling air directly leads to a reduction in the heat radiation efficiency. As a countermeasure against this, conventionally, a reduction in the speed and amount of the cooling air due to an increase in the air resistance due to the radiation fins 20 will be compensated for by increasing the size of the fan for sending the cooling air and increasing the amount of the cooling air (increasing the wind speed). And had

If the air boundary layer near the radiating fins 20 is thick, heat is not efficiently transferred from the radiating fins 20 to the air, and the radiation efficiency is immediately reduced. Conventionally, there have been few attempts to make the air boundary layer thinner. In particular, the heat radiation fins 20 were only considered to have a shape that only improves the heat radiation efficiency, and were not considered to have a shape that reduced the air boundary layer.

An object of the present invention is to provide a heat sink device which realizes a high heat radiation function by making the shape of the heat radiation fin a shape suitable for controlling the boundary layer. Also, the present invention
It is an object of the present invention to provide a heat sink device that realizes a high heat radiation function by combining a shape suitable for boundary layer control with a shape of a heat radiation fin and a shape suppressing air resistance.

[0009]

FIG. 1 shows a heat sink device according to the present invention. FIG. 1 (A) is a plan view, FIG. 1 (B) is a front view, and FIG. 1 (C) is a side view. The heat sink device of the present invention includes a base 1 and a plurality of radiation fins 2 projecting from the base 1. Each radiating fin 2 is formed in a plate (flat plate) projecting substantially vertically from the base 1. A plurality of plate-like radiating fins 2 are arranged in a plurality of rows in the first direction in a shape when the radiating fins 2 are viewed from above. This first direction coincides with the direction of the flow of the cooling air, as described later.

Further, in the shape of the radiating fins 2 when viewed from above, each of the rows is composed of a plurality of plate-shaped radiating fins 2, and the plate-shaped radiating fins 2 constituting the row are adjacent to each other. In the rows, they are arranged at different positions in the first direction. That is, they are arranged in a staggered manner. Furthermore, in the shape when the heat radiation fins 2 are viewed from above, of the plurality of heat radiation fins 2 arranged in a staggered manner, at least upstream or downstream of the plate-shaped heat radiation fins 2 at a predetermined position. The side ends are bent in a second direction. The second direction intersects the first direction at a predetermined angle.

According to the heat sink device of the present invention, the plurality of plate-shaped radiating fins 2 are arranged in a plurality of rows in the first direction corresponding to the direction of the flow of the cooling air. Thereby, the cooling air can be taken into the heat radiation fin 2 without resistance on the upstream side (fan side) of the heat radiation fin 2.

In addition, according to the heat sink device of the present invention, the radiating fins 2 are arranged in a staggered manner in each of the rows, and are at least at predetermined positions among the radiating fins 2 in each of the rows. The upstream end or the downstream end of the radiation fin 2 is bent in a second direction or a third direction intersecting at a predetermined angle with respect to the first direction. By this bending, a part of the flow of the cooling air taken into the radiation fin 2 is intentionally disturbed, so that the air boundary layer formed on the surface of the radiation fin 2 is thinned (or eliminated). The heat conductivity of the radiation fin 2 can be increased.
In addition, by bending the flow of the cooling air, which has disturbed the flow, in an intended direction by the bending, the cooling air is intentionally applied to the central portion of the high-temperature radiating fin 2 to collect the cooling air, and the cooling air is collected. Can efficiently dissipate heat.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat sink device according to the present invention will be described in detail with reference to FIG. The base 1 of the heat sink device is usually fixed to a mounting surface on an upper surface of a package of a high heat generating element such as an LSI. For this purpose, the base 1
Has a square plate shape, and its lower surface is a flat surface. A plurality of radiation fins 2 of the heat sink device are provided on the upper surface of the base 1. Each radiating fin 2 has a base 1
And a substantially plate-like shape protruding substantially vertically therefrom.

The size of the actual heat sink device is substantially the same as a heat sink device model 34 (see FIG. 3) described later. That is, the width L of the base 1 = 16.6.
5 mm, length W of base 1 = 60.0 mm, radiation fin 2
Is H = 35.0 mm. Therefore, FIGS. 1A and 1C do not show the length of the base 1 in the longitudinal direction.

As shown in FIG. 1A, the shape (plan view) of the heat sink device or the radiation fin 2 when viewed from above.
, A plurality of plate-shaped heat radiation fins 2 are arranged in a plurality of rows in the first direction. This first direction corresponds to the direction of the flow of cooling air (air) supplied from a fan (not shown) (arrow in the figure). Fig. 1 Cooling air
Since the air flows in the direction of the arrow in FIG. 1A, the right side in FIG. 1A is the upstream side, and the left side is the downstream side.

As shown in FIG. 1B, in the shape (front view) of the radiation fin 2 when viewed from the front, a linear passage for the cooling air is secured from upstream to downstream of the flow of the cooling air. ing. On the other hand, as shown in FIG. 1C, in the shape (side view) of the radiation fin 2 when viewed from the side, there is no linear passage of the cooling air in the direction crossing the flow of the cooling air.

In practice, a high heat-generating element such as an LSI to which the heat sink device of the present invention is mounted is mounted on a mounting board (see FIG. (Not shown).
Thereby, the cooling air can be taken into the heat radiation fin 2 without resistance upstream of the heat radiation fin 2 (fan side). At this time, the right side in FIG. 1A is set to the upstream side.

Further, as shown in FIG. 1A, in the shape of the radiating fins 2 when viewed from above, each of the rows is composed of a plurality of plate-shaped radiating fins 2, and the plate constituting the row is formed. Radiating fins 2 are arranged at mutually different positions in the first direction in rows adjacent to each other. That is, they are arranged in a staggered manner.

Further, as shown in FIGS. 1A and 2A, among the plurality of radiating fins 2 arranged in a staggered manner, at least a plate-shaped radiating fin located at a predetermined position is provided. The two upstream or downstream ends are bent in a second direction. The second direction intersects the first direction at a predetermined angle θ2. Similarly, at least the end of the plate-shaped heat radiation fin 2 at a predetermined position is bent in the third direction. The third direction intersects the first direction at a predetermined angle θ3. Thereby, the end of the radiation fin 2 is bent in a direction opposite to the second direction. FIG. 2A schematically shows a part of the planar configuration of the heat sink device shown in FIG.
This corresponds to FIG.

More specifically, in the heat sink device shown in FIG. 1A, in the shape of the heat radiation fin 2 when viewed from above, the heat radiation fin 2 The downstream end is bent in the second direction, and the downstream end of the radiation fin 2 is bent in the third direction in the even rows of the plurality of rows. That is, the downstream ends of the radiation fins 2 in a plurality of rows are alternately bent in opposite directions.

As a result, according to this aspect, as will be described later, there are a gap where the air resistance to the cooling air is larger than when there is no bending, and a gap where the air resistance is the same (rather smaller) as when there is no bending. Occur alternately. The reason why the air resistance increases is that the gap is substantially narrowed by bending both the adjacent radiation fins 2 inward of the gap. The reason why the air resistance is rather small is that the gap is substantially widened by bending both the adjacent radiation fins 2 outwardly of the gap.

Further, in the heat sink device of the present invention, the flow of the cooling air inside the gap defined by the adjacent radiation fins 2 is asymmetric with respect to the center line. Further, the flow of the cooling air inside the adjacent gaps is made different, and the same flow of the cooling air is generated alternately between the plurality of gaps.

Here, the reason why an increase in air resistance does not cause a decrease in heat radiation efficiency in the heat sink device of the present invention will be described. By bending the end portion of the plate-shaped heat radiation fin 2 in the second direction and / or the third direction, as shown in FIG. ), The air resistance to the cooling air taken into the radiation fins 2 is slightly increased. Therefore, it seems that this reduces the flow rate of the cooling air and reduces the efficiency of heat radiation from the radiation fins 2.

Generally, in a viscous flow of air, an air boundary layer (a layer with a slow flow velocity) is formed on the surface of the radiation fin 2. In particular, in the heat sink device of the present invention, the direction in which the plate-shaped radiating fins 2 extend (first direction) is matched with the direction of the flow of the cooling air, so that the air boundary layer is easily formed. This air boundary layer hinders heat radiation from the radiation fins 2.

However, due to the bending, as shown in FIG. 2A, a part of the flow of the cooling air taken into the radiation fin 2 is intentionally disturbed (indicated by an arrow in the figure). This makes it possible to reduce the thickness of the air boundary layer (layer having a low flow velocity) formed on the surface of the radiation fin 2 in the flow of the viscous air. In particular, the air boundary layer can be almost eliminated on the upstream side. Therefore, the radiation fin 2 is controlled by the boundary layer control using the bending of the radiation fin 2.
The efficiency of heat radiation from the device can be increased. The improvement of the heat radiation efficiency by disturbing the cooling air is larger than the decrease of the heat radiation efficiency by the increase of the air resistance caused by the bending.

Further, by this bending, as shown in FIG. 2A, the flow of the disturbed cooling air is bent in an intended direction. Thereby, the cooling air can be intentionally applied to the central portion (the area surrounded by a circle in the figure) of the radiating fin 2 having a high temperature (represented by an arrow in the figure). Therefore, it is possible to increase the flow rate of the cooling air that hits a high-temperature portion and efficiently radiate heat from that portion. As a result, the improvement of the heat radiation efficiency by bending the flow of the cooling air can be made sufficiently larger than the decrease of the heat radiation efficiency by the increase of the air resistance caused by the bending.

Therefore, in the heat sink device shown in FIG. 1A, in the plurality of rows formed by the radiating fins 2, the downstream end of the radiating fin 2 is moved in the first direction, that is, in the direction of the flow of the cooling air. Reverse direction alternately for each row (angles θ2 and θ3)
This improves the efficiency of heat radiation. The heat sink device of the present invention can control the direction of the cooling air passing between the radiating fins so that the cooling air can take more heat from the radiating fins 2, so that heat can be efficiently radiated. .

The increase in the air resistance due to the bending of the flow of the cooling air is caused by the fact that a part of the disturbed cooling air flows from the gap between the radiating fins 2 arranged in a staggered manner to the space between the other radiating fins 2. To some extent is compensated.
This is because, as described above, there is a gap where the air resistance to the cooling air is smaller than when there is no bending,
it is obvious. Accordingly, it is possible to prevent the cooling air from flowing out above the heat radiation fins 2 (peeling in the vertical direction of the base 1). As a result, it is possible to prevent the speed and amount of the cooling air flowing between the heat radiation fins 2 from being reduced, and the heat radiation efficiency from being reduced. Therefore, the size of the fan for sending the cooling air is increased, and the amount of the cooling air is increased (the wind speed is increased).
Therefore, it is not necessary to compensate for the decrease in the speed and amount of the cooling air due to the increase in the air resistance.

[0029] The second direction and the third direction are respectively the first direction.
The angles θ2 and θ3 that intersect with the direction are made equal. Therefore, the angles θ2 and θ3 are equal in magnitude and differ only in sign. The magnitudes of the angles θ2 and θ3 (the amount of bending) are set to appropriate values (described later) so that the heat radiation efficiency is maximized (the boundary layer control is optimal).

The positional relationship (bending direction) between the radiation fin 2 whose end is bent in the second direction and the radiation fin 2 whose end is bent in the third direction is a predetermined relationship. You. Further, in the plate-shaped radiating fins 2 arranged so as to match the direction of the flow of the cooling air, whether the upstream or downstream end thereof is bent or both ends are bent (bending position). , A predetermined relationship. A predetermined relationship is also established between the direction of the bending and the position of the bending.

In the plurality of rows formed by the heat radiation fins 2, it is optional to determine which of the rows is an odd row and which is an even row. In FIG. 1A, the rightmost column in the figure may be an odd column or an even column. In addition, the second direction and the third direction
It is optional that any one of the directions described above be the bending direction to the right and left sides in the figure. In FIG. 1A, the bending direction to the right in the drawing may be the second direction or the third direction.

As described above, in the heat sink device of the present invention, the positional relationship (bending direction) with the radiation fins 2 bent in the second direction and the third direction, the upstream side and / or the downstream side of the radiation fins 2 By variously selecting whether to bend the end on the side (bending position) and how much to bend the end of the radiation fin 2 (the amount of bending), various kinds of control are performed so as to optimize the boundary layer control. Deformation is possible.

FIG. 2B shows another embodiment of the present invention, and schematically shows a planar shape of a heat sink device of the present invention, and is a view corresponding to FIG. 2A. The shapes of the front and side surfaces in this embodiment are shown in FIGS.
Since it is similar to (C), its illustration is omitted (the same applies to the following embodiments).

In FIG. 2B, in the shape of the radiating fin 2 when viewed from above, the downstream end of the radiating fin 2 is provided every other one of the plurality of rows formed by the radiating fin 2. The portion is bent in a second direction. That is, this embodiment is different from the embodiment shown in FIG.
This is an embodiment in which bending of the downstream end portion of the first side in the third direction is omitted. Therefore, only in the odd rows (or even rows) of the plurality of rows formed by the radiation fins 2, the downstream end of the radiation fins 2 is bent in the second direction.

According to this aspect, the air resistance that increases by bending the end of the radiation fin 2 is slightly smaller than that in the embodiment shown in FIG. On the other hand, the effect of thinning the air boundary layer on the surface portion of the radiation fin 2 by bending and the effect of increasing the flow rate of the cooling air corresponding to the high temperature of the radiation fin 2 are slightly smaller than those in the embodiment shown in FIG. . Therefore, this mode is, for example, that the fan for sending out the cooling air is not so large and the LS
This is selected when the heat radiation from I and the like is not so large.

When the radiation fins 2 are viewed from above, the downstream ends of the radiation fins 2 are bent in the second direction for each of the plurality of rows formed by the radiation fins 2. You may do it. However, in this case, FIG.
Since there is no passage (a gap between the radiation fins 2) in which the air resistance does not increase as in the embodiment of (B), it is necessary to sufficiently consider that the air resistance greatly increases.

FIG. 2C shows still another embodiment of the present invention, and schematically shows a plan shape of a heat sink device of the present invention, and is a view corresponding to FIG. 2A. In FIG. 2 (C), in the shape of the heat radiation fin 2 when viewed from above, in a plurality of rows formed by the heat radiation fins 2, every other one of the plurality of rows is upstream of the most upstream heat radiation fin 2. The side ends are bent in a second direction.

According to this aspect, by bending the upstream end portion of the radiation fin 2 on the most upstream side, the air resistance when taking in the cooling air into the radiation fin 2 is reduced in the embodiment shown in FIG. It will be bigger than that. The effect of thinning the air boundary layer on the surface of the radiating fin 2 by bending and the effect of increasing the flow rate of the cooling air corresponding to the high temperature of the radiating fin 2 are smaller than those in the embodiment shown in FIG. Therefore, this aspect is, for example, the first
(The direction of the flow of the cooling air) is small, and the increase in the air resistance does not significantly affect the heat radiation efficiency.

On the other hand, in the heat sink device of this embodiment, only the upstream end portion of the radiation fin 2 on the most upstream side needs to be bent, so that its manufacture is extremely easy and the cost is low. Therefore, the heat sink device of this aspect is suitable for a small and inexpensive heat radiating element.

FIG. 2D shows still another embodiment of the present invention, and schematically shows a plan shape of a heat sink device of the present invention, and is a view corresponding to FIG. 2A. In FIG. 2 (D), in the shape of the radiation fin 2 when viewed from above, the upstream end of the radiation fin 2 is placed in every other row of the plurality of rows formed by the radiation fin 2. 2 and the downstream end of the radiation fin 2 is bent in a third direction (bent in a direction opposite to the second direction). This embodiment differs from the embodiment shown in FIG. 2B in that the downstream end of the bent radiation fin 2 at the upstream end is bent in a direction opposite to the bending direction of the upstream end. is there. Therefore, only in the odd rows (or even rows) of the plurality of rows formed by the radiation fins 2, the upstream end and the downstream end of the radiation fin 2 are in the second direction (or the third direction) and the third direction. Bent in the direction (or the second direction).

According to this aspect, the air resistance which increases by bending the upstream end and the downstream end of the radiation fin 2 becomes larger than that in the embodiment shown in FIGS. 1 and 2B. . On the other hand, the effect of reducing the thickness of the air boundary layer on the surface of the radiation fin 2 by bending and the effect of increasing the flow rate of the cooling air corresponding to the high temperature of the radiation fin 2 are greater than those in the embodiment shown in FIG. Therefore, this mode is selected, for example, when the fan for sending the cooling air is large to some extent and the heat radiation from the LSI or the like is also large to some extent.

When the radiation fin 2 is viewed from above, the upstream end and the downstream end of the radiation fin 2 are placed in the second row for each of the plural rows formed by the radiation fin 2. (Or a third direction) and a third direction (or a second direction). However, in this case, it is necessary to sufficiently consider that the air resistance greatly increases and that the control of the flow of the cooling air becomes complicated and difficult.

[0043]

Next, a simulation performed by the present inventor to verify the effectiveness of the heat sink device of the present invention will be described. This simulation was performed using a general-purpose thermo-fluid analysis program using the finite volume method.

This simulation was performed assuming the simulation model shown in FIG. That is, a heat conductivity of 36 W / m is formed on a printed board 30 having a heat conductivity of 0.3 W / mk.
k, a heater 31 and a ceramic plate 32 having a thermal conductivity of 36 W / mk are sequentially placed, and a thermal conductivity of 1.0 W /
The heat sink device model 34 to be simulated is placed via the mk grease 33 and these are arranged inside the duct 35. The heat sink device shown in FIG. 1 was used as the heat sink device model 34.

The specifications in this simulation were set as follows. That is, the wind speed of the cooling air is 1.0 m / s,
The ambient temperature is 35 ° C., the calorific value of the heater 31 is 10 W, the material of the printed board 30 is glass epoxy resin, the thickness of the copper board of the printed board 30 is 18 μm, the size of the printed board 30 is 90 mm wide, 158 mm long, and high. 1.6mm, the size of the duct 35 is 94mm in width, 158mm in length and 40 in height
mm, the size of the heat sink device model 34 is 16.
It is 65 mm long, 60.0 mm long and 35.0 mm high. Here, the width is a dimension in a direction orthogonal to the direction of the flow of the cooling air, the length is a dimension in the direction of the flow of the cooling air (longitudinal direction), and the height is a dimension in a direction perpendicular to the base 1. .

Actually, as shown in FIG. 4A, the heat sink device model 34 is one of the heat sink devices shown in FIG.
/ 3 cut model. That is, the width (5.53 m) of 1/3 of the 16.65 mm width of the heat sink device model 34.
Only m) was analyzed. The use of this 1/3 cut model does not affect the simulation result. That is,
The lengthwise direction cannot be omitted because of the temperature distribution, but in the widthwise direction, the radiation fins 2 are arranged at a constant repetition.
If a / 3 cut model is used, a sufficient simulation result can be obtained.

Further, in the heat sink device shown in FIG. 1, in order to confirm the effect of controlling the air boundary layer, the angle θ2 between the second direction and the first direction and the angle θ2 between the third direction and the first direction are determined. The magnitude of the angle θ3, that is, the amount of bending of the radiation fins 2 was set to various values. In this simulation, the shape of the radiation fin 2 was not defined by the angle θ2 or the like, but was defined by the method shown in FIG. 4B.

That is, the distance d between the parallel portions of the adjacent plate-shaped radiating fins 2 forming a plurality of rows, and the amount of bending a of the radiating fin 2 caused by being bent in the second or third direction a
, Ie, (the amount of bending of the radiation fins 2) / (distance between parallel portions of adjacent radiation fins 2) = a / d.
The shape of the heat radiation fin 2 was defined. The bending amount a of the radiation fin 2 is a distance between a plane formed by the plate-shaped portion of the radiation fin 2 and a plane including the bent tip, as can be seen from FIG. 4B.

In each of FIGS. 5, 6 and 7,
(A) a / d = 0%, (B) a / d = 10%,
(C) shows the case where a / d = 20%, and (D) shows the case where a / d = 30%. Since d is constant, the amount of bending a, in this order,
That is, the angle θ2 and the like become large. The case of a / d = 0% is the amount of bending a = 0, that is, the case of the radiation fin 2 having only the conventional plate shape and no bending, and was similarly analyzed for comparison.

The simulation results shown in FIGS. 5, 6 and 7 show the distribution of the surface temperature of the radiating fin 2. In particular, FIG. 5 shows the temperature distribution in the lower stage of the radiation fin 2, FIG. 6 shows the temperature distribution in the middle stage of the radiation fin 2, and FIG. The lower part is the position of the heat radiation fin 2 at the height of 0 mm, the middle part is the position of the heat radiation fin 2 at the height of 17.5 mm, and the upper part is the position of the heat radiation fin 2 at the height of 35 mm. That is, the lower part is the lowermost part (substantially the surface part of the base 1) of the heat radiation fin 2, the middle part is the center of the heat radiation fin 2, and the upper part is the uppermost part of the heat radiation fin 2.

In each of FIGS. 5, 6 and 7, the six isotherms extend from 35,000 ° C. (upstream of the cooling air) to 5 ° C.
It shows a temperature distribution up to 5.000 ° C., and from the upstream side of the cooling air (indicated by an arrow in each figure), about 37.
9 ° C, about 40.7 ° C, about 43.6 ° C, about 46.4 ° C, about 49.2 ° C, about 52.1 ° C. The temperatures and positions shown are approximate values, but in the actual simulations, exactly 37.857 ° C., 40.714 ° C.,
43.571 ° C, 46.429 ° C, 49.286 ° C, 5
2.143 ° C., and the position at which the temperature was reached was also determined accurately. In the actual simulation, a temperature distribution occurs even in the radiation fins 2, but is omitted for convenience of illustration except for a part. Although not shown, a more detailed temperature distribution was obtained in an actual simulation.

As can be commonly understood from the simulation results shown in FIGS. 5, 6 and 7,
In both the middle stage and the upper stage, when a / d = 0%, the temperature distribution is similar in the width direction. That is, a similar temperature distribution is obtained in each of the gaps of the radiation fins 2. On the other hand, a / d = 10%, a / d = 20%, a / d =
In any case of 30%, gaps where the expansion of the low temperature region is small and gaps which are large are generated alternately. As described above, this is the same as the gap where the air resistance against the cooling air is large and the gap where the air resistance is not bent (rather smaller).
This is because the gap and the gap are generated alternately. This phenomenon is a / d
= 10% is small, a / d = 20% and a / d =
This is remarkable in the case of 30%. Note that more heat energy is emitted to the gap where the expansion of the low temperature region is small (that is, the gap where the air resistance increases).

From this, when a / d = 10% in any of the lower, middle and upper radiating fins 2,
It can be seen that the increase in the gap where the air resistance increases is relatively small. On the other hand, a / d = 20%, a / d = 30
%, The increase in the gap where the air resistance increases is relatively large.

On the other hand, as will be described later, since the heat radiation effect can be increased (can be set so as to be larger) than in the prior art, it can be seen that there is no problem even if a gap in which the air resistance increases is generated. Further, since the heat radiation effect can be increased as compared with the conventional case, it is understood that it is not necessary to uniformly radiate heat from both sides of the plate-shaped heat radiation fins 2. Rather, even if the air resistance of one of the gaps is intentionally increased, the amount of heat radiation from one of the side surfaces of the plate-shaped radiating fin 2 is increased. It is understood that the combined use of reducing the air resistance contributes to improving the heat radiation efficiency.

As can be seen from the simulation results shown in FIG. 5, a / d = 0%
A / d = 10%, a / d = 20%, a / d
In each case of d = 30%, the temperature is low as a whole, and the spread of the low temperature region is large. This is because the heat radiation efficiency is
= 0%). In particular, a / d =
In the case of 10%, the region exceeding 50 ° C. is scattered in only a part of the downstream side, and is hardly observed. Since it can be considered that the lower stage of the radiation fin 2 indicates a temperature close to the temperature of the heater (ie, the heating element such as an LSI), a / d = 10%
Indicates that the heat radiation effect is extremely large.

As can be seen from the simulation results shown in FIG. 6, a / d = 0%
A / d = 10%, a / d = 20%, a / d
In each case of d = 30%, the spread of the low temperature region is slightly large. In particular, the area of about 40 ° C. extends to the center of the heat sink device. When a / d = 10%, no region exceeding about 50 ° C. is observed. Although not shown, according to a detailed simulation, the temperature of the radiation fin 2 itself is more than a / d = 0% than when a / d = 0%.
The cases where d = 10%, a / d = 20%, and a / d = 30% are slightly lower.

As can be seen from the simulation results shown in FIG. 7, a result similar to the simulation result for the middle stage of the radiation fin 2 shown in FIG. In this case, though not shown, according to a detailed simulation, the temperature of the radiation fin 2 itself is more than a / d = 10% than when a / d = 0%.
%, A / d = 20%, and a / d = 30% are slightly lower.

FIGS. 8 and 9 show the temperature distribution in the upper part (upper stage) of the radiating fin 2 by focusing on the position of the radiating fin 2. The front portion is the most upstream position of the cooling air flow, the center is the middle position of the cooling air flow, and the rear portion is the most downstream position of the cooling air flow. FIG. 8 also shows the temperature inside the heater, and FIG. 9 also shows the temperature inside the heater, the temperature of the base (base portion) 1 of the heat sink device, and the exhaust temperature of the fan.

As can be seen from the simulation results shown in FIGS. 8 and 9, if a / d = 20% or less (excluding the case where a / d = 0%), the conventional (a / d = 0%) ), The temperature of each part is lower. In particular, in this range,
The temperature inside the heater can also be lower than before,
The heat dissipation efficiency is significantly improved. Further, when a / d = 10%, the temperature of each part becomes lowest. In this case, the temperature inside the heater can be reduced by 1.2 ° C. as compared with the conventional case.

On the other hand, when the radiating fins 2 are located at the front of the heat sink device, the radiating efficiency is most improved and the effect is extremely large. That is, it can be seen that the air boundary layer is substantially eliminated upstream of the flow of the cooling air. Therefore, when the length L of the heat sink device is small, the heat radiation efficiency can be greatly improved.

As described above, in the heat sink device of the present invention, a / d is substantially 20% or less (a / d = 0).
%). That is, 0% <(bending amount of radiation fin 2) / (distance between parallel portions of adjacent radiation fins 2) ≦ 20%. If a / d ≦ 20%, heat radiation efficiency equal to or higher than that of the related art (when a / d = 0%) can be obtained.

Further, it is desirable that a / d is substantially 10%. That is, (the amount of bending of the radiation fin 2) / (the distance between the parallel portions of the adjacent radiation fins 2) フ ィ ン 10% is desirable. When a / d ≒ 10%, the most excellent heat radiation efficiency can be obtained.

The inventor of the present invention conducted a simulation using a general-purpose thermo-fluid analysis program using the same finite volume method as described above, and found that the space between the radiation fins 2 in the heat sink device model 34 using the heat sink device of FIG. A similar simulation was performed for the wind speed (flow rate) distribution.

The simulation result faithfully corresponds to the simulation result on the surface temperature distribution of the radiation fin 2 described above (therefore, the description of the simulation result is omitted). That is, the wind speed in the region where the surface temperature of the radiation fin 2 is low is large, and the wind speed in the region where the surface temperature of the radiation fin 2 is high is small, and there is an extremely high correlation between the two.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments. That is, the heat sink device of the present invention is configured such that the amount and direction of the bending of the end of the radiating fin 2 and the position of the radiating fin 2 that bends the end are variously selected so that the heat radiation efficiency is maximized. Various modifications are possible.

[0066]

As described above, according to the present invention,
In the heat sink device, the plurality of plate-shaped radiating fins are arranged in a plurality of rows and in a zigzag manner in a first direction coinciding with the direction of the flow of the cooling air, and are at least at predetermined positions. By bending the upstream end or the downstream end of the radiation fin in the second direction or the third direction, the cooling air can be taken into the radiation fin without resistance, and the flow of the cooling air taken inside The cooling air that disturbed the flow can be collected at the center of the radiating fins and efficiently radiated heat, so that more cooling air can be released from the radiating fins. Can be taken away, and heat can be efficiently dissipated from an LSI or the like.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a heat sink device of the present invention.

FIG. 2 is an explanatory view of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a simulation model.

FIG. 4 is an explanatory diagram of a simulation model.

FIG. 5 is an explanatory diagram of a simulation result.

FIG. 6 is an explanatory diagram of a simulation result.

FIG. 7 is an explanatory diagram of a simulation result.

FIG. 8 is an explanatory diagram of a simulation result.

FIG. 9 is an explanatory diagram of a simulation result.

FIG. 10 is an explanatory diagram of a conventional technology.

[Explanation of symbols]

 1 base 2 radiating fin

Claims (8)

[Claims] 1. A heat sink device comprising a base and a plurality of radiating fins protruding from the base, wherein the radiating fins are formed in a plate shape substantially perpendicularly protruding from the base. Radiating fins are arranged in a plurality of rows in a first direction, and each of the rows is composed of a plurality of the plate-shaped radiating fins, and the plate-shaped radiating fins forming the row are: In the rows adjacent to each other, they are disposed so as to be different from each other in the first direction, and at least the upstream or downstream end of the plate-like heat radiation fin at a predetermined position is the first fin. The heat sink device is bent in a second direction intersecting at a predetermined angle with respect to the direction of the heat sink. 2. The method according to claim 1, wherein an upstream end of the plate-shaped heat radiation fin located at the most upstream side is bent in the second direction in every other row of the plurality of rows. A heat sink device as described. 3. The heat sink device according to claim 1, wherein a downstream end of the plate-shaped radiating fin is bent in the second direction in every other row of the plurality of rows. 4. An end portion of the plate-shaped heat radiation fin at least at a predetermined position is bent in a third direction intersecting at a predetermined angle with respect to the first direction. The heat sink device according to claim 1, wherein the heat sink device is bent in a direction opposite to the direction of (2). 5. In the odd-numbered rows of the plurality of rows, the downstream end of the plate-shaped heat radiation fins is bent in the second direction, and in the even-numbered rows of the plurality of rows, the plate-shaped heat radiation fins are provided. The heat sink device according to claim 4, wherein the downstream end of the fin is bent in the third direction by being bent in the third direction. 6. The plate-shaped heat radiation fin is bent in the second direction at every other row of the plurality of rows, and the downstream end of the heat radiation fin is bent at the third end. The heat sink device according to claim 4, wherein the heat sink device is bent in a direction opposite to the second direction by being bent in the direction. 7. A ratio of a distance between parallel portions of the adjacent plate-shaped heat radiation fins forming the plurality of rows to an amount of bending of the heat radiation fins caused by being bent in the second or third direction is: The heat sink device according to claim 1, wherein the heat sink device has a value substantially equal to or less than 20%. 8. The heat sink device according to claim 7, wherein a ratio of a distance between the parallel portions of the heat radiation fins and a bending amount of the heat radiation fins is substantially 10%.