JP2000018852A - Heat sink with heat pipe and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sink with heat pipe which can improve the heat transfer performance between a base plate and its heat pipe. SOLUTION: In a heat sink provided with a base plate 2 which is connected to an arithmetic processor 10 and has heat radiating fins 3, heat pipe attaching holes 11 formed along the surface 4 on which the fins 3 are arranged against the base plate 2, and heat pipes 14 respectively attached to the holes 11, recessed sections 12 and 15 are formed on the internal surface of each hole 11 and projecting sections 13 and 16 which are respectively inserted into the recessed sections 12 and 14 are formed on the external surface of each pipe 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink used for cooling a heating element such as an electronic component or an electronic element of an electric device, and more particularly to a heat sink with a heat pipe embedded in a base plate. is there.

[0002]

2. Description of the Related Art Electric appliances, such as personal computers, include arithmetic processing units (CPs) for the purpose of realizing multi-functions and improving the processing speed.
U, MPU) and other electronic components and electronic elements, that is, heating elements. Since these electronic components and electronic elements generate heat due to current-carrying resistance, their original functions may be impaired if overheated.

Therefore, conventionally, a heat sink has been used to dissipate the heat of these electronic components and electronic elements into the air. As an example of such a heat sink, there is a heat sink in which a plurality of plate-shaped heat radiation fins are erected on the surface of a plate-shaped base plate. As a constituent material of the heat sink, a metal material such as aluminum or copper having excellent heat conductivity is used.

The heat sink having the above configuration is used in a state where a base plate is in surface contact with the surface of a heating element. Then, the heat of the heating element is transmitted to the base plate, and the temperature difference between the surface of the radiation fin and the air causes heat to be transmitted from the surface of the radiation fin to the air, thereby preventing the heating element from overheating. Therefore, the radiation performance is enhanced as the radiation area of the radiation fin is increased.

Therefore, a heat sink with a heat pipe has been proposed in which a heat pipe mounting hole is formed in a base plate, and a heat pipe is disposed in the heat pipe mounting hole. In this heat pipe, a condensable fluid such as water or alcohol is sealed as a working fluid in a sealed metal pipe or the like in a vacuum degassed state.
The heat pipe operates by generating a temperature difference inside the heat pipe, and has a function of performing heat transport as latent heat of the working fluid by causing the working fluid evaporated in the high temperature part to flow to the low temperature part and radiate and condense. Have.

That is, according to the heat sink with the heat pipe, the heat of the base plate is transmitted to the heat pipe, and the heat is transmitted in the plane direction of the base plate by the heat pipe. Therefore, the heat radiation area of the heat radiation fin which contributes to the heat radiation is increased as much as possible, and the heat radiation performance of the heat sink is improved.

[0007]

Here, a method for manufacturing a conventional heat sink with a heat pipe will be briefly described.
First, a heat pipe mounting hole having a substantially circular cross section in a radial direction is formed in a base plate having a heat radiation fin mounting surface. Next, the heat pipe having a substantially circular cross section in the radial direction is inserted into the heat pipe mounting hole in the longitudinal direction, and the base plate and the heat pipe are integrally assembled.

As described above, in the process of manufacturing a heat sink with a heat pipe, the inner surface of the heat pipe mounting hole may come into contact with the outer surface of the heat pipe during the process of inserting the heat pipe into the heat pipe mounting hole. . Therefore, in order to suppress the frictional resistance due to the contact between the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe, the outer diameter of the heat pipe mounting hole is set to be slightly larger than the outer diameter of the heat pipe in advance. I have.

However, when the outer diameter of the heat pipe mounting hole is set to be slightly larger than the outer diameter of the heat pipe, the inner surface of the heat pipe mounting hole and the heat pipe are not connected when the heat pipe is mounted on the base plate. There is a gap between the outer surface and the outer surface. As a result, in the use state, the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe come into point contact in the circumferential direction (line contact in the longitudinal direction), and the contact area is reduced, and the heat transfer performance is reduced. Could be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a heat sink with a heat pipe capable of improving heat transfer performance between a base plate and a heat pipe.

[0011]

Means for Solving the Problems and Action Therefor To achieve the above object, a first aspect of the present invention relates to a base plate connected to a heating element and having a radiating fin arrangement surface, In a heat pipe with a heat pipe having a heat pipe mounting hole formed along the radiating fin arrangement surface and a heat pipe disposed in the heat pipe mounting hole, an inner surface of the heat pipe mounting hole and an outer surface of the heat pipe In addition, irregularities having different heights in the radial direction and interlocking with each other are formed.

According to the first aspect of the present invention, the contact area between the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe is increased by the engagement of the concave and convex portions.

According to a second aspect of the present invention, a heat pipe mounting hole is formed on a base plate connected to a heating element and having a radiating fin arrangement surface along the radiating fin arrangement surface. In the method for manufacturing a heat sink with a heat pipe in which a heat pipe is inserted into a mounting hole in a longitudinal direction, before inserting the heat pipe into the heat pipe mounting hole, the outer surface of the heat pipe has a different radial height. After forming the concave and convex portions, by inserting the concave and convex portions into the inner surface of the heat pipe mounting hole in the process of inserting the heat pipe into the heat pipe mounting hole, the outer surface of the heat pipe and the heat pipe mounting hole The inner surface is brought into close contact with the inner surface.

According to the second aspect of the present invention, in the step of inserting the heat pipe into the heat pipe mounting hole, the concave and convex portions on the outer surface of the heat pipe bite into the inner surface of the heat pipe mounting hole, and the outer surface of the heat pipe is connected to the heat pipe mounting hole. The inner surfaces of the holes are in close contact with each other, and the mutual contact area is increased.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a heat sink with a heat pipe and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings. The heat sink with a heat pipe is used for cooling an office equipment, for example, an arithmetic processing unit (CPU, MPU) arranged inside a housing of a personal computer.

FIG. 1A shows a heat sink with a heat pipe according to the present invention (hereinafter simply abbreviated as a heat sink).
FIG. 1B is a side sectional view of the heat sink 1. The heat sink 1 includes a rectangular parallelepiped base plate 2 and a plurality of radiating fins 3 erected on one surface 4 of the base plate 2. That is, surface 4
Corresponds to the radiation fin arrangement surface of the present invention. The base plate 2 and each of the radiation fins 3 are made of a metal material having excellent heat conductivity, for example, aluminum, copper, or the like. In the manufacturing process, the base plate 2 and the heat radiation fins 3 may be integrally molded or may be separately molded and then joined. Base plate 2
Has another surface 5 parallel to the surface 4 and the surface 5
And the arithmetic processing unit 6 as a heating element are in surface contact (close contact)
are doing.

The base plate 2 has surfaces 4, 5
Are formed at right angles to the surface. further,
Arithmetic processing unit 6 in the direction from surface 7 to surface 8
Is set to be shorter than the length of the surface 5 in the direction from the surface 7 to the surface 8. The close contact region between the arithmetic processing unit 6 and the surface 5 is set to a partial region of the surface 5, specifically, a region biased toward one surface 8.

On the other hand, each radiating fin 3 provided on the surface 4
Are formed in a substantially square shape, and the dimensions of the heat radiation fins 3 are set to be the same. Further, the base plate 2 has other surfaces 9 and 10 formed at right angles to the surfaces 4 and 5 and the surfaces 7 and 8 and parallel to each other. The radiation fins 3 are arranged in parallel with each other and at regular intervals, and the radiation fins 3 are arranged so as to be parallel to the surfaces 9 and 10.

The base plate 3 has a plurality of heat pipe mounting holes 11 formed on the front surface 7 and the front surface 8 thereof. Each heat pipe mounting hole 11 has a surface 4
And a center line (not shown) in the radial direction of each heat pipe mounting hole 11 and the surfaces 4 and 5 are set in parallel. That is, each radiation fin 3 and each heat pipe mounting hole 11 are arranged in parallel.
The intervals between the center lines of the heat pipe mounting holes 11 are set to be the same.

Further, on the inner surface of each heat pipe mounting hole 11, a concave portion 12 having a square front shape and a convex portion 13 having a square front shape are alternately formed in the circumferential direction. That is, on the inner surface of each heat pipe mounting hole 11, internal teeth are formed by the concave portion 12 and the convex portion 13. This recess 12
The protrusions 13 are formed over the entire length of each heat pipe mounting hole 11 in the length direction. As described above, the front shape of the heat pipe 14 and the front shape of the heat pipe mounting hole 11 are configured to be substantially the same or similar.

A heat pipe 14 is disposed in the heat pipe mounting hole 11. This heat pipe 14
Inside a sealed container such as a metal pipe,
In a vacuum degassed state, a condensable fluid such as water, alcohol, methanol, acetone, ammonia, helium, sodium, and nitrogen is sealed as a working fluid.
The material of the container constituting the heat pipe 14 is copper,
Aluminum, steel, stainless steel, nickel, titanium,
Inconel is exemplified. The heat pipe 14
It is also possible to provide a wick for promoting the reflux of the working fluid inside the container.

The cross section of the heat pipe 14 in the radial direction is substantially circular. Further, on the outer periphery of the heat pipe 14, concave portions 15 having a rectangular front shape and convex portions 16 having a rectangular front shape are alternately formed in the circumferential direction. That is, the recess 15 is formed on the outer surface of the heat pipe 14.
And external teeth are formed by the projections 16. The concave portion 15 and the convex portion 16 are formed over the entire length of each heat pipe 14. And the heat pipe mounting hole 11
The internal teeth formed on the inner surface of the heat pipe 14 and the external teeth formed on the outer surface of the heat pipe 14 are meshed with each other.

Next, a method of manufacturing the heat sink 1 will be described. As a method of manufacturing the heat sink 1, two types of manufacturing methods are exemplified. The first manufacturing method is a manufacturing method in which the concave portion 12 and the convex portion 13 are formed in advance on the inner surface of the heat pipe mounting hole 11. The second manufacturing method is a method in which a concave portion 12 and a convex portion 13 are formed on the inner surface of the heat pipe mounting hole 11 in a process of inserting the heat pipe 14 into the heat pipe mounting hole 11.

The steps of manufacturing the heat sink 1 of FIG. 1 by the first manufacturing method will be described.
Is machined to form a heat pipe mounting hole 11 therethrough. Next, the inner surface of the heat pipe mounting hole 11 is machined to form the concave portion 12 and the convex portion 13. On the other hand, the heat pipe 14 is separately manufactured, and the concave portion 15 and the convex portion 16 are formed on the outer surface of the heat pipe 14. Here, the diameter of the circumscribed circle of the concave portion 12 of the heat pipe mounting hole 11 is set to be larger than the diameter of the circumscribed circle of the convex portion 16 of the heat pipe 14. The diameter of the inscribed circle of the convex portion 13 of the heat pipe mounting hole 11 is set to be larger than the diameter of the inscribed circle of the concave portion 15 of the heat pipe 14.

Thereafter, when the heat pipe 14 is inserted into the heat pipe mounting hole 11, a gap is formed between the inner surface of the heat pipe mounting hole 11 and the outer surface of the heat pipe 14 based on the above-described dimension setting. For this reason, the frictional resistance between the inner surface of the heat pipe mounting hole 11 and the outer surface of the heat pipe 14 is suppressed, and assembling workability is improved. Also, the first
In the assembled state of the heat sink 1 manufactured by the manufacturing method described above, the concave portion 15 and the convex portion 16 on the outer surface of the heat pipe 4 and the concave portion 12 and the convex portion 13 on the inner surface of the heat pipe mounting hole 11 are engaged with each other. Therefore, there are a plurality of contact portions in the circumferential direction.

When the heat sink 1 is manufactured by the first manufacturing method, a gap is formed between the outer surface of the heat pipe 14 and the inner surface of the heat pipe mounting hole 11. That is, a so-called spline fitting state is achieved in which the heat pipe 14 and the heat pipe mounting hole 11 are fitted so as to be relatively movable in the axial direction.

Next, the steps of manufacturing the heat sink 1 of FIG. 1 by the second manufacturing method will be described. First, the base plate 2 is machined to penetrate the heat pipe mounting hole 11. On the other hand, the heat pipe 14 is separately manufactured, and the concave portion 15 and the convex portion 16 are formed on the outer surface of the heat pipe 14. Here, the diameter of the circumscribed circle of the protrusion 16 is set to be larger than the inner diameter of the heat pipe mounting hole 11.

Thereafter, when the heat pipe 14 is inserted (press-fitted) into the heat pipe mounting hole 11 in the longitudinal direction, the protrusion 16 bites into the inner surface of the heat pipe mounting hole 11 due to the press-fitting load. Therefore, the inner surface of the heat pipe mounting hole 11 is deformed to form the concave portion 12 and the convex portion 13, and the inner surface of the heat pipe mounting hole 11 and the heat pipe 14 are formed.
The outer surface of the That is, when the heat sink 1 is manufactured by the second manufacturing method, no gap is formed between the inner surface of the heat pipe mounting hole 11 and the outer surface of the heat pipe 14.

When the heat sink 1 is manufactured by the second manufacturing method, there is no gap between the outer surface of the heat pipe 14 and the inner surface of the heat pipe mounting hole 11. That is, the heat pipe 14 and the heat pipe mounting hole 11 are fitted in a state where they cannot be moved relative to each other in the axial direction, that is, a so-called serration fitting state.

When the heat sink 1 shown in FIG. 1 is disposed inside the housing of the personal computer and the base plate 2 is in close contact with the processing unit 6, the heat of the processing unit 6 is transmitted to the base plate 2. Is done. Specifically, the light is transmitted to the right side area of the surface 5 in FIG. Part of the heat transmitted to the base plate 2 is mainly transmitted to the right side area of the radiating fins 3, and is transferred to the air due to the temperature difference between the surface temperature of the radiating fins 3 and the temperature of the air.

When a part of the heat transmitted to the base plate 2 is transmitted to the heat pipe 14, the heat pipe 14 operates due to a difference in temperature therein.
Specifically, in FIG. 1B, the working fluid evaporates in the right side region (evaporating portion) in the longitudinal direction of the heat pipe 14, and passes through the substantially central heat insulating portion, and condenses on the left side in the longitudinal direction of the heat pipe 14. The heat is conveyed as latent heat of the working fluid by flowing to the section and releasing and condensing the heat. The apparent thermal conductivity of the heat pipe 14 is about several tens to several hundred times better than metals such as copper and aluminum.

In this way, the heat transmitted to a part of the surface 5 of the base plate 2 is dispersed in the plane direction of the surface 4 of the base plate 2 by the heat transport function of the heat pipe 14. For this reason, heat is radiated over the entire area of the heat spread fins 3 in the longitudinal direction, and the effective heat radiating area of each heat spread fin 3 is enlarged. Therefore, the cooling performance for the arithmetic processing unit 6 is improved.

In the heat sink 1 manufactured by the first manufacturing method, the recess 15 of the heat pipe 14
And the convex portion 16 and the concave portion 12 of the heat pipe mounting hole 11.
And the convex portion 13 are meshed with each other. In the heat sink 1 manufactured by the second manufacturing method, the concave portion 15 and the convex portion 16 of the heat pipe 14 and the concave portion 12 and the convex portion 13 of the heat pipe mounting hole 11 are formed over the entire area in the circumferential direction. Closely adhered. Therefore, even when the heat sink 1 is manufactured by any of the first and second manufacturing methods, the contact area between the heat pipe 14 and the base plate 2 is enlarged, and the heat transfer performance is improved. Therefore, the cooling performance for the arithmetic processing unit 6 is further improved.

Incidentally, in the embodiment of FIG. 1, the front shape of the concave portion and the convex portion may be a mountain shape, an involute shape or the like.

FIG. 2 is a side sectional view showing another embodiment of the heat sink 1 of the present invention. In the embodiment of FIG. 2, a male thread 17 is formed on the outer surface of the heat pipe 14. A female thread 18 is formed on the inner surface of the heat pipe mounting hole 11. The male screw 17 is screwed into the female screw 18. The male screw portion 17 and the female screw portion 18 correspond to the uneven portion of the present invention. The male screw part 17 and the female screw part 18 are formed over the entire area in the circumferential direction, and the heat pipe 14 and the base plate 2 are formed.
And are screwed together.

The steps of manufacturing the heat sink 1 of FIG. 2 by the above-described first manufacturing method will be described. A male screw part 17 is formed on the outer surface of the heat pipe 14 in advance, and a female screw part 18 is formed on the inner surface of the heat pipe mounting hole 11. Then, the heat pipe 1 is inserted into the heat pipe mounting hole 11.
By inserting the heat pipe 4 while rotating it, the heat pipe 14 and the base plate 2 are integrally assembled.

Therefore, the male screw portion 17 and the female screw portion 18
Is formed between the heat pipe 14 and the base plate 2 so that the heat pipe 14 and the base plate 2 can be relatively rotated. Also in the embodiment of FIG. 2, since the male screw portion 17 and the female screw portion 18 are meshed with each other, the contact area between the outer surface of the heat pipe 14 and the inner surface of the heat pipe mounting hole 11 is enlarged, and The heat transfer performance with the base plate 2 is improved.

When the heat pipe 14 and the base plate 2 are screwed together, a tapping screw-shaped male screw portion can be formed on the outer surface of the heat pipe 14. When this configuration is adopted, the heat sink is manufactured by the above-described second manufacturing method. That is, a male screw portion having a tapping screw shape is formed on the outer surface of the heat pipe, and a heat pipe mounting hole having a substantially circular cross section is formed in the base plate. Then, in the process of inserting the heat pipe into the heat pipe mounting hole while relatively rotating the base plate and the heat pipe, the tapping screw bites into the inner surface of the heat pipe mounting hole to form a female screw.

As described above, when the operation of inserting the heat pipe into the heat pipe mounting hole is completed,
The outer surface of the heat pipe and the inner surface of the heat pipe mounting hole come into close contact with each other. Therefore, even when this configuration is adopted, the contact area between the outer surface of the heat pipe and the inner surface of the heat pipe mounting hole is enlarged, and the heat transfer performance between the heat pipe and the base plate is improved.

The heat sink with a heat pipe is used for office equipment other than a personal computer, for example, electronic parts such as a copying machine, a facsimile, a printer, and a word processor.
It is also possible to apply to cooling of an electronic element.

[0041]

As described above, according to the first aspect of the present invention,
The contact area between the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe is increased by the engagement of the concave and convex portions. Therefore, the contact area between the outer surface of the heat pipe and the inner surface of the heat pipe mounting hole is increased, and the heat transfer performance between the heat pipe and the base plate is improved.

According to the second aspect of the present invention, in the process of inserting the heat pipe into the heat pipe mounting hole, the concave and convex portions on the outer surface of the heat pipe bite into the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe and the heat pipe mounting. The inner surface of the hole is in close contact. Therefore, the contact area between the outer surface of the heat pipe and the inner surface of the heat pipe mounting hole is increased, and the heat transfer performance between the heat pipe and the base plate is improved.

[Brief description of the drawings]

FIG. 1A is a front view showing an embodiment of a heat sink with a heat pipe of the present invention, and FIG. 1B is a side sectional view of the heat sink with a heat pipe.

FIG. 2 is a side sectional view showing another embodiment of the heat sink with a heat pipe of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat sink, 2 ... Base plate, 3 ... Radiation fin, 4 ... Surface, 10 ... Processing unit, 11 ... Heat pipe mounting hole, 12, 15 ... Depression, 13, 16 ...
Convex part, 14 ... heat pipe, 17 ... male screw part, 1
8 Female thread part.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Katsuo Eguchi 1-5-1, Kiba, Koto-ku, Tokyo Stock Company Inside Fujikura (72) Inventor Tan Nuen 1-5-1, Kiba, Koto-ku, Tokyo F-term (reference) 5F036 AA01 BA08 BB05 BB60 BC31

Claims (2)

[Claims] 1. A base plate connected to a heating element and having a radiation fin arrangement surface, a heat pipe attachment hole formed along the radiation fin arrangement surface with respect to the base plate, and a heat pipe attachment hole. In the heat pipe with a heat pipe having a heat pipe disposed on the inner surface of the heat pipe mounting hole and the outer surface of the heat pipe, uneven heights having different radial heights and meshing with each other are formed. A heat sink with a heat pipe. 2. A heat pipe mounting hole is formed on a base plate connected to a heating element and having a radiating fin arrangement surface along the radiating fin arrangement surface. In the method of manufacturing a heat sink with a heat pipe in which the heat pipe is inserted in the longitudinal direction, before inserting the heat pipe into the heat pipe mounting hole, uneven portions having different radial heights are formed on an outer surface of the heat pipe. After that, in the process of inserting the heat pipe into the heat pipe mounting hole, the concave and convex portions are cut into the inner surface of the heat pipe mounting hole, thereby bringing the outer surface of the heat pipe into close contact with the inner surface of the heat pipe mounting hole. A method for producing a heat sink with a heat pipe.