JPH06109384A - Structure of sealing part of heat pipe - Google Patents

Abstract

PURPOSE:To restrict a stress crack at a time of pressurizing and deformation at a sealing part and improve a strength at the sealing part by a method wherein a heat pipe to which a pipe wall is press contacted is formed with a sealing part divided into many branch sections and an outer diameter of sectional surface at the sealing part is set within an outer diameter at the sectional surface of a main body of a container. CONSTITUTION:A main body 1 of a container constituting a heat pipe is made such that a pipe wall is press contacted with a sealing part 2 of one end of the pipe. The sealing part 2 to which the pipe wall is press contacted is formed in four branches 21 in a sectional surface crossing at a right angle with a pipe axis of the main body 1 of the container where they are extended from a center in a radial direction at an equal angular spacing of about 90 deg., for example, along a direction of the pipe axis. A height of each of the branches 21 in its circumferential direction is set substantially in an equal spacing and a diameter (r) of a circle connecting each of the extremity ends is formed to be substantially coincided with an outer diameter R at the end surface of the main body 1 of the container. In addition, each of the branches 21 is formed with a plurality of corrugations 22 along its height direction. In addition, in order to form the sealing part 2, four press dies 3 are equally spaced apart around the main body 1 of the container in a circumferential direction and these are concurrently pressurized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a heat pipe sealing portion structure, and more specifically, a small-sized device such as an LSI, an IC or other electronic element or an electronic device using these. The present invention relates to a sealing part structure suitable for a sealing part of a heat pipe having a small diameter (for example, an outer diameter of 5 mm or less) that cools a heating element having a high heat density.

[0002]

2. Description of the Related Art As a means for sealing a container constituting a heat pipe, in order to reduce a thermal influence at the time of sealing a heat pipe, a portion to be sealed of the container is pressed with a press die from two directions. Thus, a method is adopted in which the pipe wall is pressed and pressed flatly, and in this pressed state, ultrasonic vibration is applied to the press die for sealing. However,
In this way, since the flat width of the sealing portion protrudes from the cross-sectional outer diameter of the container and occupies a large space, and the strength of the sealing portion is apt to decrease, the flatness is improved. And as shown in FIG. 8 (for example, Japanese Patent Laid-Open No. 61-
No. 134592), the cross-sectional shape of the sealing portion 2 of the container body 1 is semicircular, U-shaped, dogleg-shaped or U-shaped in a pressing process using a press die (not shown). Means of forming into a letter shape has been proposed.

[0003]

The problems such as the reduction in strength of the end portion of the heat pipe and the increase in occupied space can be solved to some extent by the above-mentioned means, but new problems have been pointed out. That is, when the sealing portion is processed as described above, when the portion to be sealed of the container is pressure-molded with a press die into, for example, a semicircular shape, a part of the portion in the circumferential direction (see FIG. 7).
The amount of deformation of the portion of the sealing portion 2 where the pipe wall overlaps) becomes extremely large as compared with other portions, and stress cracking may occur during processing. In order to prevent this stress cracking, if the bending portion 20 of FIG. 8 is set at a gentle bending angle as shown by the chain double-dashed line in the figure, the length of the bending portion 20 becomes longer, and the bending portion 20 becomes longer. Since the cross-sectional area is smaller than that and the heat transfer function is also inferior, the effective length as a heat pipe, in other words, the effective heat transfer area is reduced accordingly.

Further, when the press die is used to continuously process the shape as shown in FIGS. 7 and 8, the outer diameter of the arc of the sealing portion 2 becomes slightly larger than the cross-sectional outer diameter of the container body 1, and the container body 1 is When the doughnut-shaped fin is attached, there is a problem that the fin cannot be inserted from the end portion on the sealing portion 20 side. When the fin as described above is attached to the container body 1 having the arcuate sealing portion 2 formed thereon from the end portion on the sealing portion 2 side,
Since a step of further pressurizing and compressing the sealing portion 2 is required,
This leads to a decrease in productivity.

The object of the present invention is to improve the above-mentioned problems, to reduce the risk of stress cracking when the intended sealing portion of the container body is deformed under pressure, and to improve the strength of the heat pipe sealing portion. It is an object of the present invention to provide a heat pipe sealing portion structure which is higher in shape, can increase the effective length of the heat pipe, and is not obstructive when the fins are mounted on the container.

[0006]

In order to achieve the above-mentioned object, a heat pipe sealing portion structure according to the present invention comprises a heat pipe sealing portion to which a pipe wall is pressure-contacted, which constitutes the heat pipe. In the cross-section orthogonal to the tube axis of the container body, it is formed in three or more limbs radially extending from the central portion, and the outer diameter of the sealing portion in the cross-section is within the cross-sectional outer diameter of the container body. It was formed in. It is preferable that the respective limbs have substantially the same height in the circumferential direction, and that the adjacent limbs are formed at substantially equal angular intervals. Further, in the sealing portion structure according to the present invention, when the pressure contact portion is finally sealed, the portion is sealed by brazing, ultrasonic welding or other welding.

[0007]

According to the heat pipe sealing portion structure of the present invention, as described above, when the sealing portion is viewed in the end face direction, three or more limbs extending radially from the center (the tube axis of the container body) are provided. Since it is configured, the strength against external force from the circumferential direction and the axial direction is higher. When the sealing portion is formed into the shape as described above, the portion to be sealed of the container body is simultaneously pressed in the pipe axial direction with a press die from three or more circumferential directions. Since it is sufficient to perform pressure deformation from the outer diameter to near the pipe axis, the amount of deformation is much smaller than the amount of deformation of the pipe wall inside the arc in the sealing part of Fig. 7, and stress cracking during molding is also very small. Become. For the same reason, the length of the sealing portion can be further shortened, so that the effective length of the heat pipe can be correspondingly increased. In addition, since the cross-sectional outer diameter of the sealing portion is formed so as to be within the cross-sectional outer diameter of the container body, the sealing portion does not interfere when the fin is inserted from the end portion on the sealing portion side.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a heat pipe sealing portion structure according to the present invention will be described with reference to FIGS. 1 is an end view of a sealing portion showing a first embodiment of the sealing portion structure according to the present invention, FIG. 2 is a partial sectional view taken along the arrow AA of FIG. 1, and FIG. 3 shows a second embodiment. An end view of the sealing portion, FIG. 4 is a partial sectional view taken along the arrow BB of FIG. 3, FIG. 5 is an end view of the sealing portion showing the third embodiment, and FIG. 6 is a sealing showing the fourth embodiment. It is an end view of a part.

In FIGS. 1 and 2, a container body 1 forming a heat pipe is a pipe made of a copper alloy having an outer diameter of 5 mm and an inner diameter of 4.6 mm, and a pipe wall of the sealing portion 2 at one end thereof is pressure-welded. Has been done. Sealing part 2 in which the pipe wall is pressed
Is formed in four limbs 21, 21, 21 in the cross section orthogonal to the tube axis of the container body 1 and extending radially from the center at equal angular intervals of approximately 90 °, along the tube axis direction, The heights of the respective limbs 21 in the circumferential direction are substantially equal to each other, and the diameter r of the circle connecting the tips of the limbs 21 is processed so as to substantially match the cross-sectional outer diameter R of the container body 1. In this embodiment, each minute limb 21 is formed with a plurality of streaky irregularities 22 along the height direction thereof.

To mold the sealing portion 2 as described above, as shown in FIG. 1, four press dies 3 each having a molding surface of a right angle in cross section are equiangularly spaced in the circumferential direction of the container body 1. Is installed in the direction of the container body 1, and this press die 3 is simultaneously operated in the pipe axis direction of the container body 1 from the circumferential direction to pressurize the portion of the container body 1 to be sealed. With this pressure, 4
Two limbs 21 are molded.

Strip-shaped irregularities 3 are formed on the molding surface of each press die 4.
If 0 is formed, streak-like irregularities 22 are formed on each of the limbs 21 along the height direction. After pressure molding as described above, when ultrasonic vibration is applied to any two press dies 3 in an unpressurized state by an ultrasonic oscillator (not shown), the pressure contact portion of the tube wall of the sealing portion 2 is They are joined together and sealed. The pressure-welded tube walls can be joined to each other by brazing or other welding means instead of the above-mentioned example.

In the structure of the sealing portion of the above-mentioned embodiment, since the cross section of the sealing portion which is orthogonal to the tube axis is formed in a + shape, the main body 1
The above-mentioned shape enhances not only the external force along the length direction of the above, but also the external force from the circumferential direction. In addition, the deformation amount of the pipe wall in the planned sealing portion is almost evenly distributed to each of the limbs 21, and the pipe wall is only deformed from the outer peripheral portion of the container body 1 to the vicinity of the pipe axis. Since it is much smaller than that in the conventional sealing structure shown in FIG. 7, stress cracking at the time of molding is also extremely reduced. For the same reason, since the length of the sealing portion 2 can be made shorter, the effective length of the heat pipe can be made larger. Furthermore, because of the shape of the sealing portion, it is very easy to fit the cross-sectional outer diameter of the sealing portion 2 within the cross-sectional outer diameter of the container body 1 by one-time processing. The productivity for processing so that the fin can be inserted from the end portion is improved as compared with the conventional example.

In the second embodiment shown in FIGS. 3 and 4, a circle 23 connecting the distal ends of the respective limbs 21 in the sealing portion 2 (see FIG. 3).
Is smaller than the outer diameter R of the container body 1. As shown in the drawing, after molding each of the limbs 21 having no unevenness as in the first embodiment,
The pressure contact portion is hermetically sealed by brazing or welding. Other configurations, operations and molding methods of the sealing portion structure of this embodiment are substantially the same as those of the first embodiment, and therefore their explanations are omitted.

In the sealing portion structure of the third embodiment shown in FIG. 5, the sealing portion 2 has three limbs 21, and the adjacent limbs 21 are arranged at equal angular intervals of approximately 120 °. Is molded into. The limbs 21 of the sealing portion 2 are not formed with the unevenness as in the first embodiment. Since the number of the limbs 21 in this embodiment is three, it is suitable when using a container having a smaller diameter. Other configurations,
Since the operation and the method of forming the split limb 21 are almost the same as those of the first embodiment, their description will be omitted.

In the sealing portion structure of the fourth embodiment shown in FIG. 6,
The diameter of a circle 23 connecting the tips of the respective limbs 21 is formed to be smaller than the outer diameter of the container body 1. The other construction, function and molding method in this embodiment are substantially the same as those in the third embodiment, and therefore their explanations are omitted.

In the present invention, the number of the split limbs 21 in the sealing portion 2 is not particularly limited, but when a container having a small diameter is used, the workability is preferably 3 to 4 as in the above embodiment. . As a material of the container, it is preferable to use copper or a copper alloy, aluminum or an alloy thereof, which has good thermal conductivity.

[0017]

EFFECTS OF THE INVENTION In the heat pipe sealing portion structure according to the present invention, the deformation amount of the pipe wall at the time of processing is dispersed to each limb and becomes relatively small, so that the stress cracking at the time of processing becomes small, and the sealing is performed. Due to the shape of the stopper, the strength against external force is increased and the durability is further enhanced. In addition, since it is easy to fit the cross-sectional outer diameter of the sealing portion within the cross-sectional outer diameter of the container body, when the sealing portion is located at the end, the fin can be attached from the end side. Such a heat pipe can be manufactured with high productivity. Furthermore, since the length of the sealing portion can be reduced by further strengthening the sealing portion, it is possible to manufacture a heat pipe having a larger effective length.

[Brief description of drawings]

FIG. 1 is an end view of a sealing portion of a heat pipe showing a first embodiment of a sealing portion structure according to the present invention.

FIG. 2 is a partial cross-sectional view taken along the arrow AA of FIG.

FIG. 3 is an end view of the sealing portion of the heat pipe showing the second embodiment of the sealing portion structure according to the present invention.

FIG. 4 is a partial cross-sectional view taken along the arrow BB of FIG.

FIG. 5 is an end view of the sealing portion of the heat pipe showing the third embodiment of the sealing portion structure according to the present invention.

FIG. 6 is an end view of the sealing portion of the heat pipe showing the fourth embodiment of the sealing portion structure according to the present invention.

FIG. 7 is an end view of a sealing portion of a conventional heat pipe.

8 is a vertical sectional view of a sealing portion of the heat pipe of FIG.

[Explanation of symbols]

 1 Container body 2 Sealing part 20 Bending part 21 Minor limb 22 Concavo-convex 23 Circle connecting the tip of the limb 3 Press die 30 Concavo-convex

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kenji Matsuoka 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Minor Sakashita 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Junji Saya 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Kenichi Namba 2-6, Marunouchi, Chiyoda-ku, Tokyo No. 1 inside Furukawa Electric Co., Ltd.

Claims (3)

[Claims] 1. A sealing portion of a heat pipe, to which a pipe wall is pressed, has three or more limbs radially extending from a central portion in a cross section orthogonal to a pipe axis of a container body forming the heat pipe. A heat pipe sealing portion structure, characterized in that the outer diameter of the sealing portion in the cross section is within the outer diameter of the cross section of the container body. 2. The heat pipe according to claim 1, wherein each of the limbs has substantially the same height in the circumferential direction, and the adjacent limbs have substantially equal angular intervals. Sealing structure. 3. The heat pipe sealing portion structure according to claim 1, wherein the pressure contact portion of the sealing portion is sealed by brazing, ultrasonic welding or other welding.