JPH03263591A - Radiator for cooling element and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost of the title radiator by a method wherein the radiator is constituted of a square flat plate heat receiving unit, in which one parts of respective spiral rings of a loop type fine tube container which forms circular or rectangular coil are bonded to neighboring spiral rings sequentially, and the group of heat radiating fins, constituted of remaining spiral rings. CONSTITUTION:When a radiator is formed, fine tube 1 for the container of a loop type fine tube heat pipe is wound around a core member 7 having a predetermined sectional configuration. Under a condition as it is, one parts of respective spiral rings which form a coil are bonded through a predetermined bonding means so that neighboring similar parts of respective neighboring spiral rings are bonded sequentially to each other and the bonded parts form a square plate surface 2 as a whole. Subsequently, the square plate surface 2 is formed so as to be a smooth flat plate while the core member 7 is removed before or after forming the flat plate to obtain the configuration of the fine tube coil 1 which is easily ventilated. The heat radiating unit has a large radius of curvature and, therefore, shaping is easy and it can be deformed in accordance with the size of a heat generating element 3. On the other hand, the pressure loss of operating liquid is reduced and, therefore, the heat radiating capacity of the radiator is improved. A connecting tube 6 is made by connecting both terminal ends of the fine tube container so as to constitute a loop.

Description

Detailed Description of the Invention A.8 Objective of the Invention [Field of Industrial Application] The present invention relates to the structure of a heat pipe and its manufacturing method, and in particular to the structure of a loop-type thin tube heat pipe applied as a radiator for cooling elements. and its manufacturing method.

[Prior Art] Cooling of small heating elements, such as various semiconductor elements used in electronic devices, using heat pipes is accomplished by mounting a plurality of elements on a common cold plate and cooling the cold plate with the heat pipe. It was customary. This is because there were no small heat pipes on the market that could be mounted on individual elements.

Recently, loop type thin tube heat pipe JP-A-63-31849
With the advent of No. 3, individual cooling of elements is becoming possible. The conventional loop type thin tube heat pipe type radiator shown in Figure 6 (a) Front view (B) Side view is 40mm x 40mm.
Although it has a high ability to remove 70 W of heat from the surface of an element with a cooling air flow of about 3 m/s, its complicated manufacturing process makes it expensive and it has not become popular. 2 is a heat dissipating part of the loop-type thin tube heat pipe, 2 is a heat receiving part thereof, 3 is a heating element, and 6 is a terminal connecting part of the loop. The diameter of the thin tube used is 0.8 mm to 1
．． In many cases, there are six cabinets.

[Problems to be Solved by the Invention] In the loop type thin tube heat pipe type radiator illustrated in FIG. 6, the working fluid circulates in the loop at high speed due to the temperature difference between the heat receiving and radiating parts, increasing the temperature of the heat radiating part. Efficiency (releases heat in the cooling air) Despite its small size and high performance, its widespread use has been slow due to its structure, which makes it difficult to reduce its price, and its complicated manufacturing process, which is unavoidable due to the structure. Figures 7 to 11
The figure shows the characteristics of the manufacturing process.

FIG. 7 is a process for forming a helical body consisting of a bent part and a straight part with a radius of curvature of +nm. Since the radius of curvature of the bent part is small, there is a risk of the thin tube becoming swamped, making it difficult to aim at high speed. Another problem is that the winding speed of the straight portion and the bent portion is significantly different, making it impossible to wind the winding at a high speed as a whole.

Fig. 8 This is the process of developing the spiral body into a meandering shape. For each turn, it is necessary to apply a twist to either the helical vehicle side or the meandering body side, which is a major problem as it is difficult to increase speed and automate it.

Figure 9: Alignment process, heat dissipation section 1 in the straight section (
(outside the broken line) to reduce the spacing between the tubules. This is a problematic process that cannot be automated. In the figure, 4 and 5 are both ends of the thin tube.

FIG. 10 This is a step of forming a portion that will become the heat receiving portion 2. A predetermined portion of the thin tube is bonded to adjacent thin tubes using an adhesive having good thermal conductivity to form the heat receiving portion flat plate 2. When bonding, a formwork is used to ensure a good flat surface and dimensional accuracy. This step is also a problematic step that consumes a lot of time.

Fig. 11 is a process for forming the heat dissipation part. The thin tubes 1 of the heat dissipation section are arranged in a portion where convection air flows to form a multi-tubular heat dissipation section. This is a difficult and problematic process, as it requires manual labor to bend and arrange each thin tube one by one. After completing each of the above steps, the ends 4 and 5 of the capillary are airtightly connected with the connecting pipe 6 to complete the loop-type capillary container, and then a predetermined working fluid circulation means is installed and a predetermined A predetermined amount of working fluid is sealed to complete a loop-type capillary heat pipe type heat radiator for the device.

All of the steps shown in FIGS. 7 to 11 are inefficient, difficult to automate, and pose problems, and all of them are causes of price increases.

Structure of the Invention [Means for Solving the Problems] The basic structure and manufacturing method of the loop-type thin tube heat pipe, which is the basis of the heat radiator for cooling elements, remains unchanged, but the shape of the radiator is changed and the following changes are made. The molding process will be significantly changed. The shape of the modified radiator is as illustrated in FIG. 1 (a) front view and (b) side view. A portion of the spiral ring is sequentially bonded to a similar portion of each adjacent spiral ring by a predetermined bonding means, and the mutually bonded portion is formed into a rectangular flat plate as a whole and is formed as a heat receiving portion. , the remaining part of each spiral ring forming the coil is the radiation fin group 1
It is characterized by being structured as In the figure, reference numeral 3 denotes a heating element, which is bonded to the heat receiving section 2 by a predetermined means. Reference numeral 6 denotes a connecting tube that connects both ends of the thin tube container to form a loop. The arrows indicate the flow of convective wind for heat radiation.

As the shape of the heat radiator as described above changes, the molding process also needs to be significantly changed. The molding process is characterized by including the following three steps as illustrated in FIGS. 3, 4, and 5.

The first step (FIG. 3) is the step of winding the container capillary tube 1 of the loop-type capillary heat pipe around the outer periphery of the core material 7 having a predetermined cross-sectional shape.

Second step (Fig. 4) While the thin tube l is wound around the outer periphery of the core material 7,
A portion of each helical ring forming the coil is sequentially adhered to a similar and identical portion of each adjacent helical ring by a predetermined adhesive means, and the mutually bonded portion forms a rectangular plate surface 2 as a whole. The process of bonding.

Third step (FIG. 5) A step of forming the rectangular plate surface into a smooth flat plate, removing the core material 7 before or after forming, and shaping the thin tube coil 1 into a shape that allows easy ventilation.

[Function] (Function of the shape of the radiator) (a) Since the radius of curvature of the heat radiating part is large, it is easy to shape the heat radiating part, and it is not only easy to shape the heat radiating part to a state where ventilation is easy. As shown in (b), the height, width, etc. of the heat dissipation section can be freely adjusted, and can be deformed to correspond to various sizes of heat generating elements.

(b) Since the circulating flow of the working fluid circulates in the same direction and with the same curvature without repeating sudden turns, the pressure loss in the working fluid flow is reduced, the circulating speed of the working fluid is increased, and the heat dissipation capacity is improved. is improved.

(C) As will be described later, the molding of the heat sink becomes extremely easy.

(Effect of the forming process) The coil winding of the thin tube in the first process can be carried out at high speed. A commercially available coil winding machine can be used for the coil winding work, and automation is also easy.

The second step, the bonding step, can be carried out without removing the core material while the first step is completed, eliminating the need for thin tube alignment for bonding as in the past, and improving the accuracy of the bonded part shape. There is no need for formwork to obtain it. Furthermore, it is easy to automate the bonding work.

Third step: It is easy to smooth the rectangular plane of the bonded portion while the core material is still attached, and shaping to facilitate ventilation after removing the core material is also extremely easy compared to the conventional method.

[Example] A radiator for cooling an element was manufactured using a thin tube having an outer diameter of 1 mm and an inner diameter of 0.8 mm as a container thin tube of a loop-type thin tube heat pipe using the manufacturing method according to the present invention.

The first step is to create a cross-sectional shape with an outer diameter of 50 m+ as shown in Figure 3.
The experiment was conducted using a core material made of Teflon TFE with a flat cutting width of 40 mm. The number of turns of the coil wound around the core material was 40 turns in close winding. Because the radius of curvature is large, the sixth
Compared to the conventional structure shown in the figure, there was no risk of thin tube deformation, no manufacturing loss, and winding was completed at high speed. It only took a few seconds.

The second step was performed with Pb-5n solder to 40+nm
A rectangular adhesive part (heat receiving surface) with a size of 40 mm was formed. Due to the heat resistance and heat insulation properties of the core material TFH, solder bonding on the flat portion of the core material was extremely easy, and the process was completed in a few seconds. Third
Smoothening of the rectangular bonded area in the process was completed by simply pressing for 3 seconds against the flat surface of a thick aluminum plate that had been preheated to 250°C. Removal of the core material was extremely easy due to the good slipperiness of Teflon TFE.The shaping of the heat dissipating tubes for good ventilation was also done by pressing every other helical ring once at the same time using a tool prepared in advance. It was completed. The time from start to completion of these three steps was only about 5 minutes per piece, including allowance time. Compared to the conventional process shown in FIGS. 7 to 11, which required 120 minutes per piece, the work was an incomparably short time.

After the third step is completed, the ends of the thin tubes are connected to each other, a check valve is provided as a working fluid circulation means, a predetermined amount of working fluid is sealed, and a heat radiator for cooling an element as illustrated in FIG. completed. A heater with a heat dissipating surface of 40+m x 40 mm was bonded to the heat receiving surface of the completed heat sink using low temperature solder, and a wind speed of 3 t was applied.
A temperature rise test was conducted in the AGS wind tunnel. Ambient temperature 2
The electrical input to the heater was 80 W to stabilize the temperature of the adhesive surface between the heater and the heat receiving plane at 65° C. at 5° C. That is, the total thermal resistance of the heat sink was R=0.5° C./W.

The total thermal resistance of a loop-type capillary heat pipe type radiator of the same size and conventional structure manufactured with the structure shown in Figure 6 is R = 0.57.
℃/W, it was found that there was a significant improvement in performance.

C1. Effects of the Invention The structure of the device cooler according to the present invention makes it possible to significantly improve the performance of a small heat sink, that is, a loop-type capillary heat pipe for cooling a single device. Furthermore, the novel structure enables a novel manufacturing method according to the invention. This new manufacturing method dramatically reduces the processing time required to manufacture conventional loop-type thin tube heat pipe type element heat sinks, and it brings the manufacturing costs, which were far from practical use, to practical use. It has the great effect of reducing costs to the lowest possible level.

Furthermore, each of the three steps in the method for manufacturing a heat sink for device cooling according to the present invention is a manufacturing method that can easily manufacture automated equipment, and by shifting to an automated mass production method, the manufacturing cost can be further reduced. Expected to decrease.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the structure of a heat sink for cooling an element according to the present invention. (A) Front view (B) Side view Figure 2: t#(() and ([1) are respectively front views showing usage examples of the heat sink in Figure 1. Figure 3 is an element according to the present invention. It is a perspective view which shows the 1st process of the manufacturing method of the cooling radiator. FIG. 4 is a front sectional view which shows the 2nd process same as the above. FIG. 5 is a front view which shows the 3rd process same as the above. Figure 6 shows a conventional loop-type capillary heat pipe heat sink (
2 is a schematic diagram showing a heat sink for cooling an element. (A) Front view (B) Side view FIGS. 7, 8, 9, 10, and 11 are schematic diagrams showing the manufacturing process of the element cooling radiator shown in FIG. 6 in order. 1... Thin tube corresponding to the heat radiating part of the loop-type thin tube heat pipe or the heat radiating part 2... Rectangular flat plate 3 corresponding to the heat receiving part or the heat receiving part...
Heating element 4... One end of both ends of the thin tube 5... One end of both ends of the thin tube 6... Connecting tube 7... Core material

Claims (2)

[Claims] (1) Both ends of the capillary are connected airtight to each other to form a loop-type capillary container, and the working fluid is circulated in a predetermined direction by a predetermined means within the container, dissipating heat from the heat receiving part of the container. The loop-type capillary container is formed into a circular or square coil shape, and each spiral ring forming the coil has a predetermined bond at a part thereof. The mutually bonded portions are sequentially bonded to the similar identical portions of each adjacent helical ring by means, and the mutually bonded portions are formed as a whole into a rectangular flat plate and configured as a heat receiving portion, and the remaining portions of the core helical ring are 1. A radiator for cooling an element, characterized in that the whole is configured as a group of radiating fins. (2) After forming the capillary into a predetermined shape, both ends of the capillary are airtightly connected to each other to form a loop-type capillary container, and a predetermined working fluid circulation means is provided within the loop-type capillary container. A method for manufacturing an element cooling radiator constituted by a loop-type thin-tube heat pipe in which a predetermined amount of working fluid is then sealed in a loop-type thin-tube container, the method comprising: During the process of forming the thin tube into a predetermined shape, there is a first step of winding the thin tube into a coil around the outer periphery of a core material with a predetermined cross-sectional shape, and then, in that state, each spiral ring forming the coil is a second step of sequentially adhering similar parts of each adjacent spiral ring to one another using a predetermined adhesion means so that the mutually bonded parts form a rectangular plate surface as a whole; It is characterized by including three steps: a third step of forming the rectangular bonded part into a smooth flat plate, removing the core material at any point before or after that, and shaping the shape of the thin tube coil into a shape that facilitates ventilation. A method for manufacturing a heat sink for cooling an element.