JP2005180723A - End sealing method for heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end sealing method for a heat pipe capable of sealing a nozzle part with sufficient airtightness, and capable of enhancing reliability. <P>SOLUTION: After injecting a working fluid into a container 2 and exhausting non-condensable gas from the container 2, an injection nozzle 7 is sealed by spot welding in a state of cutting off communication of the injection nozzle 7. By this, even when minute gaps are formed along a radiating direction of the injection nozzle 7 by swaging process, the injection nozzle 7 itself is welded so as to fill the gaps in a spot-welded portion, and intrusion of non-condensable gas such as atmospheric air from the injection nozzle 7 into the container 2 can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pipe that transfers heat by latent heat of vaporization of a working fluid, and uses a nozzle portion provided in the container to inject the working fluid into the container and discharge non-condensable gas from the container. The present invention relates to a pipe end sealing method.

  Conventionally, this type of heat pipe has a condensable fluid such as pure water sealed as a working fluid in a degassed sealed metal tube, and heat is transported using the latent heat of evaporation of this working fluid. Done. Specifically, the working fluid evaporates due to heat from the outside, and the vapor flows to the low-temperature and low-pressure condensing part, and then dissipates heat and condenses, thereby transporting heat. In such a heat pipe manufacturing process, a sealing method with high airtightness is particularly required at the end where the working fluid is injected and discharged. For example, the working fluid vapor is continuously discharged by the heat evacuation method. Sealing is performed.

As a heat pipe end sealing method, for example, in Cited Document 1, a copper tube having one end sealed in advance is prepared and subjected to swaging on the open end of the tube. After forming the pipe part with a small diameter on the same axis as the central axis of the pipe and injecting and exhausting the working fluid, the pipe part is crushed in the radial direction with a punch and a die, and the inner wall surfaces of the pipe parts are In the prior art, the two are closely sealed together.
JP 2000-274974 A

  In the above-described prior art, in particular, when the groove for flowing the working fluid by capillary action is formed by the fins provided on the inner wall surface of the tube body, the opening end of the tube body is drawn and the nozzle portion and the container are drawn. Are formed along the radial direction of the nozzle portion. For this reason, sufficient airtightness cannot be obtained simply by crushing the nozzle portion with a punch and a die, and non-condensable gas such as air enters the container, causing functional failure and performance deterioration.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a heat pipe end sealing method that can seal the nozzle portion with sufficient confidentiality and can improve reliability. To do.

  According to the first aspect of the present invention, after injecting the working fluid and discharging the gas, the nozzle portion is sealed by spot welding in a state where the flow of the nozzle portion is blocked. Therefore, even if a minute gap is formed along the radial direction of the nozzle, the nozzle itself is welded so as to fill the gap in the spot-welded part. Can be prevented from entering.

  In the second aspect of the invention, the working fluid is injected and the gas is discharged using a valve mounted on the nozzle portion. Thereafter, the nozzle portion is temporarily sealed by spot welding with the valve closed. Therefore, even if a fine gap is formed along the radial direction of the nozzle part, the nozzle part itself is welded so as to fill the gap in the spot welded part, so even when the valve is removed from the nozzle part, Gases such as the atmosphere can be prevented from entering the container from the nozzle portion. In addition, the common valve can easily cut off the gas flow and the nozzle flow during spot welding.

  In addition, in this case, since the end of the nozzle portion is Tig welded after the valve is removed from the nozzle portion, coupled with the spot welding of the nozzle portion, the air density of the nozzle portion is kept double. Be drunk. Therefore, it is possible to provide a heat pipe that is extremely reliable and does not slow leak even under severe market stress.

  In the invention described in claim 3, since the tube body having a wall thickness of 0.3 ± 0.1 mm is processed by, for example, a drawing to form a nozzle portion having a smaller diameter than the container, a fine portion is formed along the radial direction of the nozzle portion. A gap is formed. Further, after injecting the working fluid and exhausting the gas, the nozzle portion is sealed by spot welding in a state where the flow of the nozzle portion is blocked. At this time, in the spot welded portion of the nozzle portion, the nozzle portion itself is welded so as to fill the gap, and the spot welded portion has a predetermined thickness of about 0.4 to 1.1 mm, for example. Can be reliably prevented from entering the container from the nozzle portion.

  In the invention according to claim 4, when the tube body is processed to form the nozzle portion, the opening diameter of the nozzle portion is set to a minimum of 0.7 mm or more so that the working fluid can be injected without hindrance. In addition, when the opening diameter of the nozzle portion is set to a maximum of 1.7 mm, the discharge of the gas and the sealing of the nozzle portion by spot welding can be facilitated. Furthermore, a nozzle portion having an outer diameter reduced to 3.2 ± 1 mm can be formed by this processing.

  In the first aspect of the present invention, the nozzle part can be sealed with sufficient confidentiality by sealing the nozzle part with spot welding in a state where the flow of the nozzle part is blocked, thereby improving the reliability. it can.

  In the invention according to claim 2, since the air density of the nozzle part is kept double, the nozzle part can be sealed with sufficient secrecy and the reliability can be further improved. It is possible to easily perform gas discharge and blockage of the flow of the nozzle portion during spot welding.

  In the invention according to claim 3, while the nozzle part is shut off, the nozzle part is sealed by spot welding, the nozzle part can be sealed with sufficient confidentiality, and the reliability can be improved. .

  In the invention according to the fourth aspect, the working fluid can be injected without any trouble, and the discharge of the gas and the sealing of the nozzle portion by spot welding can be facilitated. Furthermore, a nozzle portion whose outer diameter is reduced to 3.2 ± 1 mm can be formed.

  Hereinafter, preferred embodiments of the heat pipe end sealing method according to the present invention will be described with reference to the accompanying drawings.

  First, the overall configuration of the heat pipe 1 before sealing will be described with reference to FIG. 1 and FIG. 2. The hollow cylindrical container 2 serving as the main body of the heat pipe 1 is preferably made of a heat conductive material. It is formed from a metal pipe material that is a pipe body such as high-copper copper or aluminum that is lightweight and easy to handle. The container 2 has a linear shape as a whole, and the outer diameter and the wall thickness are constant over the entire length in the axial direction except for the end portions. Furthermore, the one end 2A of the container 2 is sealed in advance by appropriate means such as Tig welding. The outer diameter D1 of the container 2 in the present embodiment is preferably 6 ± 2 mm (4 mm or more and 8 mm or less).

  As shown in FIG. 2, the inner wall surface of the container 2 is provided with a large number of fins 4 protruding along the axial direction thereof, and a working fluid (not shown) sealed and accommodated in the container 2 between the fins 4. ) Is formed by the capillary phenomenon. Here, the height H1 of the fin 4 with respect to the inner wall surface of the container 2 is preferably 0.25 ± 0.1 mm (0.15 mm or more and 0.35 mm or less). The wall thickness T1 is preferably 0.3 ± 0.1 mm (0.2 mm or more and 0.4 mm or less). Incidentally, in the present embodiment, the groove wick structure in which the inner wall of the container 2 is made uneven is shown, but other wick structures in which a mesh or a fine line for promoting the flow of the working fluid is provided on the inner wall of the container 2 can be adopted Good.

  An injection nozzle 7 as a nozzle part having a smaller diameter than that of the container 2 is integrally formed at the other end 2B of the container 2 that is opened. The injection nozzle 7 is preferably coaxial with the central axis of the pipe material by subjecting the other end portion of the copper pipe material having a uniform outer diameter and thickness to a drawing process such as a swaging process. When the outer diameter D1 of the pipe material and the container 2 is 6 ± 2 mm as described above, the outer diameter D3 of the injection nozzle 7 is reduced to 3.2 ± 1 mm by swaging, and The inner diameter (opening diameter) D2 of the opening 8 of the injection nozzle 7 communicating with the container 2 is reduced to 1.2 ± 0.5 mm. At this time, because the groove 5 is formed on the inner wall surface of the pipe material, a fine gap 9 is formed in the injection nozzle 7 by the groove 5 along the radial direction during swaging.

  In addition, as a method of integrally forming the injection nozzle 7 in the heat pipe 1, in addition to the above swaging process, a spinning process in which a drawing process is performed while rotating a pipe material may be employed. Any processing method has an advantage that the injection nozzle 7 having a desired shape can be formed at low cost. Further, processing other than drawing may be performed.

  Next, processing steps until the injection nozzle 7 shown in FIGS. 1 and 2 is temporarily sealed will be described with reference to FIG. In the figure, 11 is an injection / exhaust tool that is detachably attached to the injection nozzle 7 and injects a working fluid into the container 2 and discharges non-condensable gas such as air from the container. Here, as the injection / exhaust tool 11, a control valve 13 such as an electromagnetic valve provided with a mounting portion 12 for the injection nozzle 7 and a tube 14 connected to the base end portion of the control valve 13 are shown. And a pump (not shown) for feeding a working fluid into the container 2 and degassing the container 2 into a vacuum state. Reference numeral 16 denotes a pair of spot electrodes which are arranged opposite to the side surface of the injection nozzle 7 in a state where the opening 8 of the injection nozzle 7 is closed by the injection / exhaust tool 11. Is applied, and the injection nozzle 7 sandwiched between the portions is spot-welded.

  In the configuration shown in FIG. 3, the injection nozzle 7 is attached to the injection nozzle 7 at the other end of the heat pipe 1 and the opening portion of the injection nozzle 7 is opened from the tube 14 with the control valve 13 opened. 8 is injected with a working fluid such as pure water. When a predetermined amount of working fluid is injected into the container 2 from the opening 8, the container 2 is heated to a temperature equal to or higher than the boiling point of the working fluid, or a vacuum pump connected to the tube 14 (not shown). ) Is used to evacuate the opening 8 to generate a vapor of the working fluid in the container 2 and exhaust the non-condensable gas such as air together with the vapor. At that time, the control valve 13 of the injection / exhaust tool 11 controls the exhaust amount of the non-condensable gas containing the steam exhausted from the inside of the container 2 through the opening 8, and when a predetermined amount of exhaust is performed. The control valve 13 is closed to block the flow from the opening 8 of the injection nozzle 7 to the injection / exhaust tool 11.

  Next, in a state where the passage from the opening 8 by the control valve 13 is blocked, the spot electrodes 16 and 16 are moved so as to sandwich the proximal end side surface of the injection nozzle 7 from both sides, and the spot electrodes 16 and 16 are moved between the spot electrodes 16 and 16. A current is applied to temporarily seal the opening 8 of the injection nozzle 7. The injection nozzle 7 is formed with a fine gap 9 by the groove 5 along the radial direction during the swaging process, but the injection nozzle 7 is filled so as to fill the gap 9 in the spot welded seal portion. Since the welding is performed, the non-condensable gas such as the atmosphere can be prevented from entering the container 2 from the injection valve 7 even after the injection / exhaust tool 11 including the control valve 13 is removed from the injection nozzle 7.

  After performing the spot welding, the injection / exhaust tool 11 including the control valve 13 is removed from the injection nozzle 7, and the corresponding portion of the injection nozzle 7 to which the mounting portion 12 of the injection / exhaust tool 11 is connected is cut. 4 and 5, Tig welding is performed on the cut end portion 21 of the injection nozzle 7. In addition, the code | symbol 22 shown in FIG. 4 is the temporary sealing part formed in the injection | pouring nozzle 7 by the said spot welding. The temporary sealing portion 22 is formed so that the thickness is 0.4 mm or more and 1.1 mm or less when the outer diameter D1 of the container 2 is 6 ± 2 mm and the outer diameter D3 of the injection nozzle 7 is 3.2 ± 1 mm. It is preferable to do this. Thus, the injection nozzle 7 formed on the opening end side of the container 2 is doubly sealed by the sealing portion of the temporary sealing portion 22 by spot welding and the end portion 21 by Tig welding, and the airtightness in the container 2 As a result, it becomes possible to improve reliability.

  In order to obtain the heat pipe 1 having excellent heat transport performance and long life in the series of manufacturing processes of the heat pipe 1, a certain amount of working fluid is injected into the container 2 and non-condensable from the container 2 It is important that the gas is reliably excluded. Therefore, in the end sealing method of the present embodiment, it is indispensable to control the discharge of the working fluid vapor from the injection nozzle 7 by the control valve 13.

  On the other hand, when sealing the end of the heat pipe 1, it is known that the method by Tig welding is the most excellent in the high airtightness and reliability. However, as also in the above-described processing steps, it is impossible to perform Tig welding on the end portion 21 with the control valve 13 connected to the injection nozzle 7, so that the base end portion of the injection nozzle 7 is temporarily sealed. After stopping, the control valve 13 is removed and the end 21 is Tig welded. In particular, in this embodiment, since the injection nozzle 7 is temporarily sealed by spot welding, unlike the conventional crushing process using a punch and a die, even if the control valve 13 is removed from the injection nozzle 7, the atmosphere such as the atmosphere Airtightness is sufficiently secured, and invasion of non-condensable gas into the container 2 can be prevented.

  As described above, in the present embodiment, the working fluid is injected into the container 2 of the heat pipe 1 and the gas from the container 2, that is, the non-condensable gas, is injected through the injection nozzle 7 as the nozzle portion provided in the container 2. After discharging, the end sealing method of the heat pipe 1 in which the injection nozzle 7 is spot-welded in a state where the flow of the injection nozzle 7 is blocked is adopted.

  In this case, after injecting the working fluid into the container 2 and discharging the non-condensable gas from the container 2, the injection nozzle 7 is sealed by spot welding in a state where the flow of the injection nozzle 7 is blocked. Therefore, even if a fine gap 9 is formed along the radial direction of the injection nozzle 7 by swaging, the injection nozzle 7 itself is welded so as to fill the gap 9 in the spot-welded portion. It is possible to prevent the non-condensable gas from entering the container 2 from the injection nozzle 7.

  In this embodiment, the working fluid is injected into the container 2 by the injection nozzle 7 provided in the container 2, and a predetermined amount of working fluid vapor is discharged by the control valve 13 as a valve attached to the injection nozzle 7. After the non-condensable gas is discharged from the container 2, the injection nozzle 7 is spot welded and temporarily sealed in a state where the flow of the injection nozzle 7 is blocked by the control valve 13. Is removed from the injection nozzle 7, and the end sealing method of the heat pipe 1 in which the end 21 of the injection nozzle 7 is preferably Tig welded is adopted.

  In this case, the working fluid is injected into the container 2, and a predetermined amount of the working fluid vapor in the container 2 is discharged using the control valve 13 attached to the injection nozzle 7, and the non-condensable gas is discharged from the container 2. . Thereafter, the injection nozzle 7 is temporarily sealed by spot welding in a state where the flow of the injection nozzle 7 is blocked by closing the control valve 13. Therefore, even if the minute gap 9 is formed along the radial direction of the injection nozzle 7, the injection nozzle 7 itself is welded so as to fill the gap 9 in the spot welded portion. Even in a state of being removed from 7, the non-condensable gas such as the atmosphere can be prevented from entering the container 2 from the injection nozzle 7. Further, the discharge of the non-condensable gas from the container 2 and the flow interruption of the injection nozzle 7 at the time of spot welding can be easily performed by the common control valve 13.

  In addition, in this case, since the end of the injection nozzle 7 is Tig welded after the control valve 13 is removed from the injection nozzle 7, the air density of the injection nozzle 7 is coupled with the spot welding of the injection nozzle 7. Is kept double. Therefore, it is possible to provide a heat pipe 1 that is extremely reliable without causing a slow leak even under severe market stress.

  Furthermore, in this embodiment, the end portion of the pipe (pipe material) having a wall thickness T1 of 0.3 ± 0.1 mm and a height 4 of the fin 4 formed on the inner wall of 0.25 ± 0.1 mm is drawn, and the injection nozzle 7 and the container 2 are formed, the injection of the working fluid from the injection nozzle 7 to the container 2 and the discharge of the non-condensable gas from the container 2 are performed, and the injection nozzle 7 is in a state where the flow of the injection nozzle 7 is shut off. A method of sealing the end of the heat pipe 1 in which the nozzle 7 is spot-welded so as to have a predetermined thickness of, for example, 0.4 to 1.1 mm is adopted.

  In this case, the end of the tubular body having the wall thickness T1 of 0.3 ± 0.1 mm and the height H1 of the fin 4 formed on the inner wall of 0.25 ± 0.1 mm is drawn, so that the injection nozzle 7 having a smaller diameter than the container 2 is provided. Since it is formed, a fine gap 9 is formed along the radial direction of the injection nozzle 7. Further, after injecting the working fluid into the container 2 and discharging the non-condensable gas from the container 2, the injection nozzle 7 is sealed by spot welding in a state where the flow of the injection nozzle 7 is blocked. At this time, in the spot welded portion of the injection nozzle 7, the injection nozzle 7 itself is welded so as to fill the gap, and the thickness of the spot welded portion becomes 0.4 to 1.1 mm. It is possible to reliably prevent the condensable gas from entering the container 2 from the injection nozzle 7.

  In this embodiment, the outer diameter D1 is 6 ± 2 mm so that the inner diameter D2 of the opening 8 which is the diameter of the injection nozzle 7 is 1.2 ± 0.5 mm and the outer diameter D3 is reduced to 3.2 ± 1 mm. The end of the tube is subjected to drawing such as swaging.

  In this case, when drawing the end of the tube, the inner diameter D2 of the opening 8 of the injection nozzle 7 is set to a minimum of 0.7 mm or more so that the working fluid can be injected into the container 2 without any trouble. In addition, by setting the inner diameter D2 of the opening 8 of the injection nozzle 7 to a maximum of 1.7 mm, it is possible to easily discharge the noncondensable gas from the container 2 and seal the injection nozzle 7 by spot welding. Further, by this drawing process, it is possible to form the injection nozzle 7 in which the outer diameter D1 is reduced to 3.2 ± 1 mm with respect to the container 2 having the outer diameter D1 of 6 ± 2 mm.

  The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, pure water that is liquid at room temperature is used here as the working fluid. However, in consideration of the heat receiving temperature of the heat pipe 1, another working fluid that is solid or gas at room temperature is enclosed in the container 2. May be.

It is a front view of the heat pipe which shows the state before inject | pouring the working fluid in this invention. It is the top view which notched a part of heat pipe in FIG. 1 same as the above. FIG. 2 is a front view of the heat pipe and its surroundings showing a state immediately before spot welding is performed with the injection / exhaust tool mounted thereon. It is a front view of the heat pipe which shows the state which the sealing process of the edge part was completed same as the above. It is a top view of the heat pipe in FIG. 4 same as the above.

Explanation of symbols

1 Heat pipe 2 Container 4 Fin 7 Injection nozzle (nozzle part)
13 Control valve (valve)

Claims (4)

A heat pipe end sealing method characterized in that working nozzle is provided and gas is discharged by a nozzle provided in a container, and the nozzle is spot welded in a state where flow of the nozzle is blocked. . The nozzle provided in the container injects the working fluid, the gas attached to the nozzle is exhausted, the nozzle is spot welded and temporarily sealed, and the valve is removed from the nozzle. A method for sealing an end of a heat pipe, wherein the nozzle portion is Tig welded. A tube body having a wall thickness of 0.3 ± 0.1 mm is processed to form a nozzle part and a container, injecting working fluid and discharging gas, and with the nozzle part being shut off, A method for sealing an end of a heat pipe, characterized by spot welding so as to have a predetermined thickness. 4. An end seal of a heat pipe according to claim 3, wherein the tube body is processed so that the diameter of the nozzle portion is 1.2 ± 0.5 mm and the outer diameter is reduced to 3.2 ± 1 mm. Stop method.

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