JP3996338B2 - Fan cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fan cooling device for cooling a heating element such as an electronic component.
[0002]
[Prior art]
Heat sinks in fan cooling devices to be mounted on electronic components such as CPUs have been produced by die casting of metals with high thermal conductivity such as Al, but the thickness of heat radiation fins that can be molded by die casting is Since the shape is limited, it has been impossible to sufficiently remove the heat generation that continues to increase with the recent increase in the speed of CPU processing. Therefore, a heat sink in which a large number of heat dissipating fins (skive fins) are integrally formed by shaving and raising an Al plate, or a thin plate-like Al is bent into an accordion shape by pressing or the like to form a heat dissipating fin (corrugated fin). A heat sink brazed onto a Cu substrate has been proposed. For example, the former heat sink is described in JP-A-8-130276, and the latter heat sink is described in JP-A-10-92986.
[0003]
[Problems to be solved by the invention]
Such skive fins and corrugated fins can reduce the thickness of the radiating fins, increase the number of radiating fins per unit area, and can freely design the shape of the radiating fins. Thereby, the heat radiation area can be increased, and the heat radiation amount and heat radiation efficiency of the heat sink can be greatly increased.
[0004]
However, skive fins and corrugated fins are difficult to precisely control the dimensional accuracy, especially the dimensional accuracy in the height direction, and the strength of the members is weak and they can be easily deformed by external force. In this fan cooling device, when the fan case is mounted on the heat sink, the heat dissipating fin may come into contact with the inner surface of the upper wall of the fan case to be deformed. For this reason, such a fan cooling device has not been generally used until now for small and thin electronic components that particularly require dimensional accuracy in the height direction.
[0005]
The present invention has been made in view of such a conventional problem, and even in a fan cooling device using skive fins and corrugated fins as heat sinks, the fan case can be used as a heat sink without deforming these radiating fins. It is an object of the present invention to be able to be used for small and thin electronic components that can be mounted and require dimensional accuracy in the height direction.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the fan cooling device of the present invention includes a heat sink having a heat radiating fin attached to a heating element, and a fan case for supporting a cooling fan for supplying a cooling air flow to the heat sink. In the fan cooling device
The fan case has an upper wall and at least a pair of engaging portions depending from the opposite side end of the upper wall, and a slit is formed in the upper wall near the base of the engaging portion to form the upper wall. The base side is bent obliquely upward, the base is positioned above the upper wall, and the fan case is attached to the heat sink by the pair of engaging portions.
[0007]
Here, from the viewpoint of increasing the elastically deformable width of the fan case and facilitating the engagement and disengagement of the fan case and the heat sink, the fan case is formed of a resin material and a claw portion is formed at the end of the engaging portion. Then, it is preferable that the fan case is detachably mounted on the heat sink by forming a recess or protrusion on the heat sink and engaging the claw portion of the engaging portion with the recess or protrusion.
[0008]
Further, from the viewpoint of facilitating the elastic deformation of the fan case, it is desirable to bend the base side of the upper wall upward within a range of 10 to 20 ° with respect to the upper wall.
[0009]
From the viewpoint of ensuring the engagement between the fan case and the heat sink, it is recommended that the engaging portions be formed at both ends of the opposite end of the upper wall.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Even if the present inventors are heat sinks having skive fins or corrugated fins that are difficult to strictly control the dimensional accuracy in the height direction, can the fan case be mounted on the heat sink without deforming these heat radiating fins? As a result of repeated studies, if the fan case is made elastically deformable, even if the radiating fin comes into contact with the fan case when the fan case is attached to the heat sink, the radiating fin is deformed by the deformation of the fan case. Has been found to be able to be avoided, and the present invention has been made.
[0011]
That is, the major feature of the fan cooling device of the present invention is that a slit is formed in the upper wall near the base of the engaging part on the fan case side that is engaged with the heat sink, and a part of the upper wall is bent obliquely upward. The base portion is positioned above the upper wall, and the fan case is attached to the heat sink by the pair of engaging portions. With such a configuration, when the fan case is attached to the heat sink, even if the radiating fin contacts the inner surface of the upper wall of the fan case, the fan case elastically deforms and absorbs the dimensional error in the height direction of the radiating fin. The deformation of the radiating fin is also prevented.
[0012]
Hereinafter, the fan cooling device of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the fan cooling device of the present invention. A fan cooling device 1 in FIG. 1 includes a heat sink 2 and a fan case 3 that is detachably attached to the heat sink 2. The heat sink 2 has a rectangular Cu substrate 21, and heat radiation fins (corrugated fins) 22 obtained by bending thin plate-like Al into an accordion shape by pressing are brazed on the upper surface of the substrate 21. A rectangular notch 23 is provided at the center of the heat radiation fin 22. When the fan case 3 is attached to the heat sink 2, a lower portion of a cooling fan (not shown) provided in the fan case 3 is accommodated in the notch 23. The notch 23 may be formed by, for example, cutting after forming the radiation fins 22 by pressing.
[0013]
In addition, concave portions 24 are formed on both sides of the substrate 21 in the horizontal direction over the entire surface. The concave portion 24 engages with a claw portion 35 at an end portion of an engaging portion 32, 32 ′ provided in the fan case 3 described later, so that the fan case 3 can be detachably attached to the heat sink 2. The depth of the recess 24 is set to a depth that allows the claw portion 35 to be reliably engaged. In FIG. 1, the concave portion 24 is formed over the entire side surface of the substrate 21, but the concave portion 24 may be formed only in a portion where the claw portion 35 at the end of the engaging portion of the fan case 3 is engaged. Of course, the fan case 3 may be provided with a recess, and the heat sink 2 may be provided with a claw or protrusion so that both can be engaged.
[0014]
The heat sink 2 is attached to a semiconductor element such as a microprocessor as a heating element. For example, an adhesive is applied to the back surface of the substrate 21 of the heat sink and fixed to a semiconductor element or the like. It is recommended from the viewpoint of heat dissipation that the heat sink is mounted so as to cover almost the entire surface of the heat generating body by making the flat shape of the heat sink substantially the same as that of the heat generating element such as a semiconductor element for cooling. Fixing of the heat sink to the heating element may be performed by screws or fixing pins in addition to the adhesive.
[0015]
The fan case 3 has a substantially square upper wall 31 and two pairs of engaging portions 32 and 32 ′ that hang down from the four corners of the opposite end of the upper wall 31. A slit 33 is formed in the upper wall in the vicinity of the base portion 34 of the engaging portions 32, 32 ′, and the base portion side of the upper wall 31 is bent obliquely upward so that each base portion 34 is positioned above the upper wall 31. ing. In the fan case of FIG. 1, the base 34 is bent upward at an angle of about 15 ° with respect to the upper wall. However, if the base 34 is bent upward at an angle of 10 ° to 20 ° with respect to the upper wall, the elasticity of the fan case is generally achieved. Deformation can be made easier. With such a configuration, when the front end portion of the heat radiating fin 22 provided on the heat sink 2 comes into contact with the lower surface of the upper wall 31 of the fan case, the upper wall 31 is deformed in an arc shape due to elastic deformation of the base portion 34, Deformation of the fin tip is prevented. The length of the slit 33 formed in the upper wall 31 and the width of the base 34 of the engaging portion may be designed so that the engaging portion is deformed by several mm in the direction perpendicular to the heat sink. What is necessary is just to determine suitably from the material of a case, the length of the hanging direction of an engaging part, etc. Generally, the length of a slit is the range of 10-20% of the width | variety of the slit formation direction (left-right direction of FIG. 1) of a fan case. Further, the width of the base portion of the engaging portion is preferably in the range of 15 to 25% of the width of the fan case (vertical direction in FIG. 1).
[0016]
As a material of such a fan case, a material having heat resistance such as engineer plastic, a low thermal expansion coefficient and excellent dimensional stability is preferable. Of these, saturated polyester is preferable from the viewpoint of ease of processing and molding, and polybutadiene terephthalate (PBT) and polyethylene terephthalate (PET) reinforced with glass fiber are particularly preferable. The glass fiber content may be appropriately determined from the required mechanical strength, dimensional stability, etc., but is generally in the range of 10 to 40% by weight, and particularly preferably in the range of 25 to 35% by weight. A method for producing a fan case using such a material is not particularly limited, and a conventionally known molding method such as injection molding can be used.
[0017]
The length of the engaging portions 32 and 32 ′ depending from the four corners of the upper wall 31 may be determined as long as the radiating fins 22 provided on the heat sink 2 do not contact the lower surface of the upper wall 31 of the fan case 3 in design. Good. A claw portion 35 projecting inward is integrally formed at the distal end portion of the engaging portions 32, 32 ′. As can be understood from FIG. 1, the claw portion 35 can be swung by elastic deformation of the base portion 34 of the engaging portion, and is formed on the side surface of the heat sink 2 by being elastically deformed somewhat outward. The fan case 3 is detachably attached to the heat sink 2 by engaging with the recessed portion 24.
[0018]
A hollow cylindrical cooling fan support 36 is integrally formed with the fan case 3 at the center of the upper wall 31. A support cylindrical wall 37 is provided inside the center of the cooling fan support 36. The support cylindrical wall 37 is supported by a crosspiece 38 formed at a distance from the peripheral wall of the cooling fan support 36 in the circumferential direction, and a suction opening 39 for sucking cooling air is formed between the adjacent crosspieces 38. Yes. A cooling fan (not shown) can be detachably attached to the cooling fan support portion 36, and the fan cooling device 1 of the present invention can be used semi-permanently by replacing the cooling fan.
[0019]
Next, an example of a method for assembling the fan cooling device having the above-described configuration will be described. In order to mount the fan cooling device on the semiconductor element as the heating element, first, a heat sink is attached to the upper surface of the semiconductor element. This attachment may be performed using an adhesive or an adhesive tape, and may be performed by screwing in order to make the attachment more reliable and strong.
[0020]
Next, attach the fan case to the heat sink. In FIG. 1, when the fan case 3 is attached, the two pairs of engaging portions 32 and 32 ′ are positioned on both side ends of the substrate 21 of the heat sink 2, and the fan case 3 faces the heat sink 2 in this state. It only has to be moved downward and attached. When mounted in this manner, the claw portion 35 at the tip of the engagement portion first contacts the side surface of the substrate 21 and spreads outward somewhat, and when the claw portion 35 reaches the recess 24, the elastic restoration of the engagement portions 32 and 32 ′ is performed. The claw portion 35 is engaged with the concave portion 24 by force. In this way, the fan case 3 is detachably attached to the heat sink 2.
[0021]
When the cooling fan is rotationally driven in a predetermined direction in this mounted state, the air sucked from the suction opening 39 of the fan case flows along the radiating fins 22 by the action of the blades. Heat from a heating element such as a semiconductor element is conducted to the plurality of heat radiation fins 22 through the heat sink substrate 21, and when the sucked air flows along the heat radiation fins 22, the heat from the heat radiation fins 22 to the air is transferred. Moving. In this way, the heat in the heating element moves from the heat sink 2 to the air flow and is removed. When removing the fan case 3 from the heat sink 2, the engaging portions 32, 32 ′ are pressed slightly outward to release the engagement between the claw portion 35 and the recessed portion 24, and the fan case is removed from the heat sink 2. 3 may be moved upward.
[0022]
In the fan cooling device of FIG. 1, two pairs of engaging portions 32 and 32 ′ are provided on the upper wall 31 of the fan case 3, but the number of engaging portions is not limited, and the engaging portions may be a pair. Of course, three or more pairs are acceptable.
[0023]
FIG. 2 shows an example in which a heat sink in which a large number of heat dissipating fins (skive fins) 25 are integrally formed by shaving and raising an Al plate is shown. In addition, the same member and part as FIG. 1 are attached | subjected the same code | symbol. In the heat sink 2 used in the fan cooling device of FIG. 2, four rows of heat radiation fins 25 that are substantially square in front view and curved in side view are formed. However, the arrangement and shape of the heat radiation fins are not particularly limited, and the material of the heat radiation fins And the amount of heat to be removed from the heating element may be appropriately determined.
[0024]
Similar to the heat sink shown in FIG. 1, concave portions 24 are formed in the horizontal direction on both sides of the substrate of the heat sink 2 in FIG. When the two pairs of engaging portions 32 and 32 ′ of the fan case 3 are positioned on the substrate of the heat sink 2 and the fan case 3 is moved downward toward the heat sink 2 in this state, the claw portion at the tip of the engaging portion First, when the side surface of the substrate comes into contact and spreads outward somewhat, and the claw portion 35 reaches the recess 24, the claw portion 35 is engaged with the recess 24 by the elastic restoring force of the engagement portion. In this way, the fan case 3 is detachably attached to the heat sink 2.
[0025]
When the fan case 3 is removed from the heat sink 2 such as when a cooling fan is replaced, the engagement portion tip part is pressed slightly outward to release the engagement between the claw portion 35 and the recess 24, and the heat sink 2 On the other hand, the fan case 3 may be moved upward.
[0026]
FIG. 3 shows another embodiment of the fan cooling device of the present invention. In addition, the same member and part as FIG. 1 are attached | subjected the same code | symbol. Most of the configuration of the fan case of FIG. 3 is the same as that shown in FIG. The only difference from the fan case of FIG. 1 is that the claw portion 35 formed at the tip of the engaging portion faces outward. On the other hand, the heat sink 2 shown in FIG. 3 has a heat radiating fin 22 in which a thin plate-like Al is bent into an accordion shape by pressing, and a notch portion 23 for accommodating a lower portion of the cooling fan is provided in the center portion. The surface of the rectangular Cu substrate 21 is brazed. The first side wall 26 is formed substantially perpendicular to the substrate 21 at both ends of the substrate 21, and a second side wall 27 is further provided between the first side wall 26 and the fins outside the heat radiating fins 22. It is provided substantially perpendicular to. On the inner surface of the first side wall 26, a projection 28 that gradually increases downward is formed. Further, flange portions 29 are extended at both ends of the substrate 21 on the side where the side wall is not formed, and a rectangular cutout portion 20 is formed at the center end portion of the flange portion 29.
[0027]
In order to mount the fan case 3 on such a heat sink 2, the engagement portions 32, 32 ′ can be inserted between the first side wall 26 and the second side wall 27 of the heat sink 2. The fan case 3 is positioned on the side. Next, the fan case 3 is moved downward in this state. At this time, the claw portion 35 formed at the tip of the engaging portion descends mainly along the inner surface of the first side wall 26 and eventually descends while sliding on the protrusion 28 formed on the first side wall 26. To do. For this reason, the engaging portions 32 and 32 'are gradually elastically deformed inward. When the claw portion 35 exceeds the projection 28, the claw portion 35 returns to its original state by the elastic restoring force of the engaging portions 32, 32 ', and thereby the claw portion 35 and the projection 28 are engaged. In this way, the fan case 3 is attached to the heat sink 2. On the other hand, when removing the fan case 3 from the heat sink 2, the engaging portions 32 and 32 'of the fan case are pressed inward to release the engagement between the claw portion 35 and the projection 28, and the fan case 3 is removed. What is necessary is just to move upward with respect to the heat sink 2. FIG.
[0028]
In order to attach the heat sink shown in FIG. 3 to a heating element such as a semiconductor element, the notch 20 formed at the center end of the flange 29 is aligned with a hole (not shown) formed in the heating element. It can be stopped or pinned. At this time, an adhesive may be used in combination to make the mounting of the heat sink 2 more reliable and strong.
[0029]
Although the embodiments of the fan cooling device of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. .
[0030]
【The invention's effect】
In the fan cooling device of the present invention, the fan case is provided with at least a pair of engaging portions depending from the opposite end of the upper wall of the fan case, and a slit is formed in the upper wall near the base of the engaging portion to Since the base side is bent obliquely upward, the base is positioned above the upper wall, and the fan case is attached to the heat sink by the pair of engaging portions. Even if it is a fan cooling device used for a heat sink, the fan case can be mounted on the heat sink without deforming these radiating fins, and it can also be used for small and thin electronic components that require dimensional accuracy in the height direction. I can do it now.
[0031]
Also, when the fan case is formed of a resin material, a claw portion is formed at the end of the engaging portion, a concave portion or a protrusion is formed on the heat sink, and the claw portion of the engaging portion is engaged with the concave portion or the protrusion, The elastic width of the fan case can be increased, and the fan case and the heat sink can be easily engaged and disengaged.
[0032]
Furthermore, if the base side of the upper wall is bent upward in the range of 10 to 20 ° with respect to the upper wall, the elastic deformation of the fan case can be further facilitated.
[0033]
When the engaging portions are formed at both ends of the opposite side end of the upper wall, the engagement between the fan case and the heat sink can be made more reliable.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a fan cooling device of the present invention.
FIG. 2 is a perspective view showing another embodiment of the fan cooling device of the present invention.
FIG. 3 is a perspective view showing still another embodiment of the fan cooling device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fan cooling device 2 Heat sink 3 Fan case 20 Notch part 21 Substrate 22, 25 Radiation fin 24 Recess 28 Protrusion 31 Upper wall 32, 32 'Engagement part 33 Slit 34 Base part 35 Claw part 36 Cooling fan support part

Claims (4)

In a fan cooling device comprising a heat sink having a heat radiation fin attached to a heating element, and a fan case for supporting a cooling fan for supplying a cooling air flow to the heat sink,
The fan case has an upper wall and at least a pair of engaging parts depending from the opposite end of the upper wall, and a slit is formed in the upper wall near the base of the engaging part to form the upper wall. A fan cooling apparatus, wherein a base side is bent obliquely upward, the base is positioned above an upper wall, and the fan case is attached to the heat sink by the pair of engaging portions. The fan case is formed of a resin material, a claw is formed at an end of the engaging portion, a recess or a projection is formed on the heat sink, and the claw of the engaging portion is engaged with the recess or the projection. The fan cooling device according to claim 1, wherein the fan case is detachably attached to the heat sink. The fan cooling device according to claim 1 or 2, wherein a base side of the upper wall is bent upward within a range of 10 to 20 ° with respect to the upper wall. The fan cooling device according to any one of claims 1 to 3, wherein the engaging portions are formed at both ends of opposite side ends of the upper wall.

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