JP2002195772A - Radiation fin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation fin which can be fixed easily to a heat pipe, having a large variation in the pitch of arrangement. SOLUTION: In a radiation fin 1, having a plurality of holes 2 for press fitting heat pipes 3, the part between the holes 2 is in a bent, curved, corrugated or meshed shape, so that the radiating fin 1 can extend/contract freely. A hollow extrusion material or a die casting material can be used in a radiation board 5 for jointing the heat pipes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a radiation fin mounted on a heat pipe.

[0002]

2. Description of the Related Art As shown in FIG. 8, a heat sink used for cooling electronic components and the like has a plurality of heat pipes 3 in each of the through holes 6 of a heat radiating substrate 5 having a plurality of heat pipe through holes 6. An exposed portion 4 is provided and joined, and a radiation fin 11 is attached to the exposed portion 4 of the heat pipe 3. Note that electronic components (not shown) are usually arranged on the heat dissipation board surface 7.

As the heat dissipation board 5, a hollow extruded material made of a conductive metal such as aluminum or copper, a die-cast material having a plurality of grooves, a hole-formed plate material, or the like is used.

[0004] The joining of the heat pipe to the heat radiating board made of the hollow extruded material is performed by inserting a heat pipe into a hole (hollow) of the heat radiating board and soldering. It is performed by a method in which the pipe is heated to increase the vapor pressure of the working fluid in the heat pipe, expanded, and the heat pipe is caulked into the hole. The joining of the heat pipe to the heat dissipation board made of die-cast material
This is performed by a method in which a heat pipe is arranged in a groove of the die casting material, and the periphery of the groove is plastically deformed to caulk the heat pipe into the groove.

The radiating fins to be attached to the heat pipe are manufactured by punching a hole for press-fitting the heat pipe into a thin plate (0.2 to 0.5 mm) made of a conductive metal such as aluminum or copper. You. The hole is subjected to burring to increase the bonding strength with the heat pipe. JIS1000 for the aluminum
System (pure Al system) or a JIS 3000 system alloy is used, and pure copper or a dilute copper alloy is used for copper.

[0006]

As described above, the heat dissipation substrate is made of hollow extruded material or die-cast material, so that it is inexpensive, but the hole interval of the hollow extruded material or the groove interval of the die-cast material has large variations. . For this reason, for example, in the heat dissipation board 5 made of a hollow extruded material, as shown in FIG. 9, the interval between the plurality of heat pipes 3 joined to the heat dissipation board 5 also becomes large. If the gap between the holes 2 is different from the gap between the heat pipes 3, the heat pipes 3 may be forcedly pressed into the holes 2 of the heat radiation fins 11. The variation in the interval between the heat pipes 3 is large in a case where the number of heat pipes is large or in a case where an exposed portion of the heat pipe is bent, and it is particularly difficult to attach a radiation fin to the heat pipe with these heat sinks.

As a countermeasure, a method has been proposed in which the hole diameter of the hollow extruded material is increased to absorb variations in the hole interval. However, this method requires a large amount of solder to be filled in the hole and increases the cost. In addition, there have been problems such as a decrease in productivity and a decrease in thermal conductivity between the heat pipe and the heat dissipation substrate.

For this reason, the heat pipe insertion holes of the heat radiating substrate are opened by using an expensive gun drill, and the holes of the heat radiating fins are also opened by using an expensive press die, and their intervals (arrangement pitch) match. However, the manufacturing cost of the heat sink is high. An object of the present invention is to provide a radiation fin that can be easily attached to a heat pipe having a large variation in arrangement pitch.

[0009]

According to the first aspect of the present invention,
A radiation fin having a plurality of holes into which a heat pipe is press-fitted, wherein the distance between the holes of the radiation fin is expandable and contractible.

According to a second aspect of the present invention, there is provided the radiating fin according to the first aspect, wherein a gap between the holes of the radiating fin is formed in a mountain shape, a curved shape, a corrugated shape, or a net shape.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the heat radiation fins of the present invention, the intervals between the holes into which the heat pipes are press-fitted are formed so as to be stretchable.
The heat pipe can be easily pressed into the hole of the radiation fin. Therefore, an inexpensive hollow extruded material, a die-cast material, or the like can be used for the heat dissipation board to which the heat pipe is joined, so that the manufacturing cost can be reduced.

Hereinafter, an embodiment of a radiation fin of the present invention will be specifically described with reference to the drawings. The heat radiation fin 1 shown in FIG. 1 is formed in a mountain shape (triangular cross section) between the holes 2, and the heat radiation fin 1 can be deformed with low stress because the heat radiation fin 1 is thin. . Therefore, the radiation fin 1
Between the holes 2 is stretchable.

FIG. 2 shows two holes 2 formed in the radiation fin 1.
FIG. 4 is an explanatory diagram of a process when two heat pipes 3 are press-fitted into each other. Here, the heat pipe 3 is joined to the heat pipe insertion hole 6 of the heat radiation board 5 by soldering, and the distance u between the two heat pipes 3 is wider than the distance t between the two holes 2. First, the hole 2 of the radiating fin 1 is positioned at the head of the heat pipe 3, and when the fin 1 is pressed downward, the hole 2 of the radiating fin 1 moves outward along the head of the heat pipe 3. The interval t between the individual holes 2 is opened and coincides with the interval u between the heat pipes 3, and the press-fitting proceeds in this state. The height of the ridges between the holes 2 decreases as the gap between the holes 2 increases, but the stress at this time is small because the thickness of the radiating fin is small, and the heat pipe does not deform. In all the drawings for describing the embodiments of the present invention, components having the same function are denoted by the same reference numerals, and their repeated description will be omitted.

When the interval u between the two heat pipes is narrower than the interval t between the two holes of the radiating fins, the interval between the two holes is reduced at the start of press-fitting, and the interval t between the holes becomes the interval u between the heat pipes. And press-fitting proceeds in this state. At this time, the height of the mountain portion between the holes 2 of the heat radiation fin 1 becomes high, but the stress at this time is small because the heat radiation fin is thin, and the heat pipe does not deform.

FIG. 3 is an exploded view of a heat sink obtained by press-fitting the heat pipe 3 into the hole of the radiation fin 1 as described above. No deformation is observed in the heat pipe 3.

FIG. 4 shows three heat pipes 3 in which each of the holes 2 of the radiating fin 1 in which three holes 2 are formed and the space between the holes 2 is formed in a mountain shape is the same as that shown in FIG. This is the heat sink attached. Here, no deformation of the heat pipe 3 is observed.

The heat radiation fin 1 shown in FIG. 5 has a curved shape between the two holes 2, this shape changes with low stress, and the space between the holes 2 is expandable and contractible. Therefore, two heat pipes having different intervals can be easily pressed into the holes 2 of the radiation fins without deforming the heat pipes.

The heat radiation fin 1 shown in FIG. 6 is formed in a corrugated shape (a large number of small peaks) between the holes 2, and this shape changes with low stress, and the space between the holes 2 is expandable and contractible. . Therefore, two heat pipes having different intervals can be easily pressed into the holes 2 of the radiation fins without deforming the heat pipes.

The heat radiation fins 1 shown in FIG. 7 are formed in a mesh shape (expander shape) between the holes 2, the shape of the heat radiation fins 1 changes with low stress, and the space between the holes 2 can be expanded and contracted. Therefore, the holes 2 of the radiating fins 1 can be easily press-fitted into the two heat pipes 3 having different intervals without deforming the heat pipes 3.

As described above, according to the present invention, the shape between the holes 2 of the heat radiation fin 1 is changed with low stress, and the space between the holes can be expanded and contracted. The inconsistency in the arrangement pitch of the pipes is absorbed by the expansion and contraction between the holes of the radiation fins, so that the heat pipe is not deformed. Therefore, if the heat radiation fin of the present invention is used, an inexpensive hollow extruded material or a die-cast material can be used for the heat radiation substrate for joining the heat pipe, and the heat sink can be manufactured at low cost.

In the present invention, the shape between the holes of the heat radiation fins is arbitrary as long as it can absorb the mismatch between the arrangement pitch of the heat pipes and the arrangement pitch of the holes of the heat radiation substrate. The shapes such as the mountain shape, the curved shape, the corrugated shape, and the net shape have a large surface area as compared with the conventional flat heat radiation fins, and thus have excellent heat radiation characteristics.

The number of ridges or curves formed between the holes may be one or more. A corrugated shape formed with a large number of mountain shapes. The larger the mountain-like angle α (see FIG. 1), the length of the curved shape and R (curvature: see FIG. 5), and the thinner the plate thickness, the smaller the deformation stress of the radiation fin,
It becomes easy to press-fit the heat pipe into the hole of the radiation fin. In the case of the radiating fin in which the gap between the holes is formed in a mesh shape, the mismatch between the arrangement pitch of the holes of the radiating fin and the arrangement pitch of the heat pipes is absorbed by expansion and contraction of the mesh portion. If provided, the unevenness of the arrangement pitch can be absorbed by the step, and the stress when the heat pipe is pressed into the hole of the radiation fin can be further reduced.

The present invention also includes a radiating fin in which the space between the holes is embossed. The radiating fins with holes formed in mesh, corrugated, embossed, etc. can be expanded and contracted to the front, back, left and right. Therefore, it is easy to arrange the heat pipes not in a straight line but in a plane (matrix). Can be attached to

[0024]

The present invention will be described below in detail with reference to examples. (Example 1) JISA3003-H1 having a thickness of 0.4 mm
A piece of 200 mm x 40 mm was cut out from the aluminum alloy plate of No. 4 and holes of 6.25 mm in diameter were formed at both ends of the plate by pressing at intervals of 150 mm at right and left symmetrical positions, and burring was performed. After that, the central portion excluding the hole was press-formed into the mountain shape shown in FIG. 1 to produce a radiation fin having a hole interval of 140 mm.

(Example 2) JISA1 having a thickness of 0.5 mm
200mm × from 100-H24 aluminum alloy plate
A plate of 50 mm is cut out, and holes of 6.25 mm in diameter are formed at both ends of the plate by pressing at intervals of 150 mm at right and left symmetric positions. After burring the hole, the center excluding the hole is removed. The portion was press-molded into the curved shape shown in FIG. 5 to produce a radiation fin having a hole interval of 140 mm.

(Embodiment 3) JISA1 having a thickness of 0.5 mm
200mm × from 100-H24 aluminum alloy plate
A 50 mm plate is cut out, and holes of 6.25 mm in diameter are formed at both ends of the plate by pressing at intervals of 180 mm at right and left symmetrical positions. After burring the hole, the center excluding the hole is removed. The portion was press-molded into a corrugated shape shown in FIG. 6 to produce a radiation fin having a hole interval of 140 mm.

(Example 4) JISA1 having a thickness of 0.5 mm
200mm × from 100-H24 aluminum alloy plate
A plate of 50 mm is cut out, and holes of 6.25 mm in diameter are formed at both ends of the plate by press working at intervals of 140 mm at right and left symmetrical positions. After burring the hole, the center excluding the hole is removed. The portion was sheared into a mesh shape as shown in FIG. 7 to produce a radiation fin having a hole interval of 140 mm.

(Comparative Example 1) JISA3 having a thickness of 0.4 mm
190mm x from 003-H14 aluminum alloy plate
A 40 mm plate was cut out, and holes having a diameter of 6.25 mm were formed at both ends of the plate by press working at 140 mm intervals at right and left symmetrical positions, and the holes were burred to manufacture heat radiation fins.

Using each of the radiation fins manufactured in Examples 1 to 4 and Comparative Example 1, 20 heat sinks were assembled. A hollow extruded material of pure Al was used for the heat dissipation substrate. A heat pipe was joined to the heat pipe insertion hole of the heat dissipation board by soldering. The dimensions of the heat pipe were 6.33 mm in outer diameter and 235 mm in length, exposing 115 mm. Heat pipe interval is 138.5-141.5m
m. This heat pipe was pressed into the hole of the heat radiation fin. The number of press-fitted radiating fins was 20 each.

In press-fitting the heat pipes, the heat radiation fins of the present invention have the heat radiation fins whose hole intervals are narrow when the heat pipe distance is smaller than 140 mm, and the heat radiation fins when the heat pipe distance is larger than 140 mm. The distance between the fins was widened, and the heat pipe could be pressed into the hole of the heat radiation fin with low stress. 20 heat sinks were assembled each, but none of the heat pipes was deformed (defective rate 0%). On the other hand, in the heat radiation fin of the comparative example, when the interval between the heat pipes was 139.5 mm or less or 140.5 mm or more, the heat pipe was bent. The ratio of the heat sink in which the heat pipe was bent (defective rate) was 35%.

The heat sinks using the heat radiation fins of the present invention of Examples 1 to 4 were incorporated in electronic equipment and used for cooling electronic parts. All of the electronic parts were cooled well and the electronic equipment was stable. Worked.

[0032]

As described above, in the heat radiation fin of the present invention, the space between the holes of the heat radiation fin for press-fitting the heat pipe is formed in a mountain shape, a curved shape, a corrugated shape, a net shape, etc., and is expandable and contractable. Also, it can be easily attached to a heat pipe having an irregular arrangement pitch. Therefore, an inexpensive hollow extruded material or a die-cast material can be used for the heat-radiating substrate for joining the heat pipe, and this has a remarkable industrial effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a radiation fin according to the present invention.

FIG. 2 is a process explanatory view (front view) when a heat pipe is pressed into a hole of a heat radiation fin shown in FIG. 1;

3 is a developed view (a plan view, a front view, and a side view) of a heat sink in which the two-hole heat radiation fin shown in FIG. 1 is attached to two heat pipes.

FIG. 4 is a development view of a heat sink of the present invention in which three-hole heat radiation fins are attached to three heat pipes.

FIG. 5 is a perspective view showing a second embodiment of the radiation fin of the present invention.

FIG. 6 is a perspective view showing a third embodiment of the radiation fin of the present invention.

FIG. 7 is a perspective view showing a fourth embodiment of the radiation fin of the present invention.

FIG. 8 is a development view of a conventional heat sink.

FIG. 9 is an explanatory view (front view) of a process when a heat pipe is pressed into a hole of a conventional heat radiation fin.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 radiating fin of the present invention 2 hole formed in radiating fin 3 heat pipe 4 exposed portion of heat pipe 5 radiating substrate made of hollow extruded material 6 heat pipe insertion hole of radiating substrate 7 radiating substrate surface on which electronic components are arranged 11 conventional Heat dissipation fins

Claims (2)

[Claims] 1. A heat radiation fin having a plurality of holes into which heat pipes are press-fitted, wherein the distance between the holes of the heat radiation fin is expandable and contractible. 2. The method according to claim 1, wherein a space between the holes of the heat radiation fin is mountain-shaped, curved,
The heat radiation fin according to claim 1, wherein the heat radiation fin is formed in a corrugated shape or a net shape.