JP2008045820A - Method of manufacturing plate-like heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a plate-like heat pipe, having good thermal conductivity and sealing ability, to which ultrasonic welding is applied. <P>SOLUTION: A capillary structure 12 made of copper having good thermal conductivity is bent to hold a support 13 made of material having good thermal conductivity, which is formed of a more coarse network structure than the capillary structure, and they are joined and integrated by ultrasonic welding, and further joined to upper and lower flat plates made of metal having good thermal conductivity by ultrasonic welding. The upper and lower flat plates are joined to seal the capillary structure and integrated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a “method for manufacturing a flat plate heat pipe”, and more particularly to a method for manufacturing a flat plate heat pipe to which ultrasonic welding is applied.

The integration density of an integrated circuit device such as a CPU is continually improved, its heat generation is increased, and if effective cooling is not possible, the processing performance of the device is affected.

As portable electronic devices are becoming more and more light and short, the problem of cooling that is confronted becomes more important, and the conventional cooling device is gradually becoming a bottleneck without obtaining a sufficient cooling effect.

Thus, the advent of flat plate heat pipes has become a good cooling device for timely portable electronic devices.

The principle of operation of a flat plate heat pipe is mostly the same as that of a conventional heat pipe. Unlike the conventional heat pipe, the outer shape of the conventional heat pipe is limited and heat can be transferred only in one dimension. Can be designed to transfer heat in a two-dimensional manner, and flat plate heat pipes can be made even thinner, and the outer shape is not limited as in conventional heat pipes, and therefore can be applied to the target cooling device. The elasticity and applicability can be greatly improved.

  FIG. 1 and FIG. 2 are views showing a conventional flat plate heat pipe. Two capillary structures 12 are sandwiched between two flat plates 11 having a relatively large cover area by sandwiching them. The support 13 is interposed between the two.

  In general, the above components are easily deformed due to thermal expansion in a high temperature environment, and gaps are likely to be formed. This causes a decrease in cooling effect. Thus, it is possible to prevent a gap from being formed between the constituent members and to maintain a good heat conduction effect.

However, when performing diffusion bonding, it is necessary to position each component member, adjust the relative position between the component members, and fix each component member using a jig. A large pressure is applied to each component to form intimate contact between the components. Finally, a bond is formed between the members through a long heat treatment of 8 to 9 hours.

  The accuracy of positioning affects the cooling performance of the flat plate heat pipe. The positioning problem is clearly more important in a flat plate heat pipe with a multilayer structure.

  For example, in the structure of a flat plate heat pipe, use a metal copper mesh to form a capillary structure, and use a relatively fine mesh metal copper mesh at the point of contact with the heat source (for example, the point of contact with the CPU). The rate of vaporization upon contact with heat is improved, and the remaining part adopts a relatively coarse metallic copper mesh to improve the fluidity of the working liquid and improve the cooling effect of the entire flat plate heat pipe. At this time, in the manufacturing process, whether or not the positioning of the metal copper net having a relatively fine mesh is accurate affects the cooling effect of the flat plate heat pipe.

In addition, it is easily affected by the flatness of the jig to which pressure is applied, and when the flatness of the jig is not appropriate, the bonding density of pressure bonding between the components by the jig is likely to deteriorate, and diffusion bonding is performed. Then, the bonding strength and the tightness become insufficient, and the constituent members at the bonding locations are deformed by heat to form gaps, increasing the thermal resistance and reducing the cooling effect.
JP 2004-324906 A Japanese Patent Laid-Open No. 2003-24779

The present invention provides a method for manufacturing a flat plate heat pipe using ultrasonic welding, in which each component is easily positioned to improve the bonding strength and tightness between the components, and the manufacturing process time is reduced. The purpose is to provide.

The manufacturing method of the flat plate heat pipe to which the ultrasonic welding of the present invention is applied,
(A) At least one portion of the surface of the capillary structure is welded onto one of the upper flat plate and the lower flat plate corresponding in shape to the upper flat plate by ultrasonic waves, and the upper flat plate and the lower flat plate are mutually connected The capillary structures are arranged between the flat plates while being folded.
(B) The flat plates are joined, and the capillary structure is sealed in the flat plate.
Is included.

Ultrasonic welding is applied to join the capillary structure to one of the upper or lower flat plate, and it has good bonding strength and tightness between the capillary structure and the flat plate, effectively reducing thermal resistance. The cooling effect can be improved by lowering, and the time required for the joining process can be greatly shortened.

The manufacture of a flat plate heat pipe using ultrasonic welding provided by the present invention not only easily positions the components (capillary structure, support, flat plate, etc.) of the flat plate heat pipe, but also has the above-described configuration. It is possible to improve the bonding strength and tightness between the members, effectively reduce the thermal resistance, improve the cooling effect, and shorten the time required for the bonding process.

  In addition, the method for manufacturing a flat plate-type heat pipe to which the ultrasonic welding of the present invention is applied further includes the step of ultrasonic welding the capillary structure between the flat plates on the support that is in mutual contact with the capillary structure. It is possible to bond the capillaries and the support with good bonding strength and density, effectively reduce the thermal resistance, improve the cooling effect, and shorten the time required for the bonding process.

The manufacturing method of the flat plate-type heat pipe to which the ultrasonic welding of the present invention is applied further includes performing ultrasonic welding along the peripheral edge of the flat plate. It has good bonding strength and density, effectively reduces the thermal resistance, improves the cooling effect, and shortens the time required for the bonding process.

The manufacturing method of the flat plate-type heat pipe to which the ultrasonic welding of the present invention is applied further includes applying ultrasonic welding to join at least two child capillary structures to generate a capillary structure.

In order to further clarify the features, structure and effects achieved, embodiments of the present invention will be described in detail with reference to the drawings.

A preferred embodiment of a method for producing a flat plate heat pipe to which the ultrasonic welding of the present invention is applied includes the following steps:
First, referring to FIG. 3, in step 21, the capillary structure 31 is positioned on the support 32. The positioning method is shown in FIGS. 4 and 5, respectively.
FIG. 4 shows that the piece-like capillary structure 31 is bent to sandwich the piece-like support body 32 and uniformly contact the upper and lower surfaces of the capillary structure 31 and the support body 32. The amount of heat in the upper part 311 is distributed and transmitted to the lower part 313 via the side part 312 to efficiently improve the cooling effect.

The action of the capillary structure 31 is used to absorb the amount of heat, and the amount of heat is transmitted to the working liquid adhering to the upper part of the capillary structure 31, and the working liquid absorbs the amount of heat and sublimates to change into a gas. Let In the present embodiment, the capillary structure 31 is typically a metal copper net formed by braiding a metal copper wire with good thermal conductivity.

In addition, as shown in FIG. 5, a plurality of child capillary structures 311 can be combined to form a multilayer structure 31. Two types of metallic copper nets of different meshes are applied to form the sub-capillary structures 314 and 315, respectively, and the sub-capillary structures 314 and 315 are combined to form the capillary structure 31 to improve the overall cooling effect. Among them, by installing at a location that receives heat using a metal mesh with a relatively fine mesh (for example, a location in contact with the CPU), the vaporization rate of the working liquid adhering to it can be improved, Other locations use a metal mesh with a relatively coarse mesh to maintain good fluidity of the working fluid and improve the cooling effect.

The action of the support 32 is to provide a gap 321 that penetrates the working body 32, and the working liquid can freely flow in the gap 321. In the present embodiment, the support 32 is represented by a metal copper mesh formed by braiding a relatively rough metal copper wire, and the mesh size is larger than the mesh size of the metal copper mesh of the capillary structure 31. is there.

  As shown in FIG. 6, the capillary structure 31 is folded along both sides of the support body 32 so as to cover the support body 32, and the amount of heat located in the upper part 311 of the capillary structure body 31 is lowered through the left and right side parts 312. The cooling effect can be improved efficiently.

The positioning method of the capillary structure 31 and the support body 32 is not limited to the format shown in FIGS. 4 and 6, and the capillary structure body 31 can also cover the support body 32 as a multilayer format. The number of the capillary structures 31 and the support bodies 32 is not limited to one piece, but can be many, and the shapes thereof are not limited. The capillary structure 31 can contact only at least a part of the surface of the support 32.

  Then, as FIG. 3 shows, the process 22 joins the capillary structure 31 and the support body 32 by ultrasonic welding. As shown in FIGS. 7 and 8, the capillary structure 31 and the support 32 are joined using ultrasonic spot welding and ultrasonic roller welding, respectively.

  Further, similarly, by applying ultrasonic spot welding and roller welding, it is possible to join the child capillary structures 314 and 315 of the two different meshes to form a capillary structure.

  In the spot welding method shown in FIG. 7, an upper brush 42 is formed below the welding head 41, and the upper brush 42 and the lower brush 44 installed on the mounting table 43 correspond to each other. In operation, the capillary structure 31 and the support 32 are first positioned and placed between the upper and lower brushes 42 and 44, the upper brush 42 is pressed downward, and the capillary structure 31 and the support 32 are moved to the upper and lower brushes 42 and 44. Hold tightly between. When the welding head 41 interlocks with the upper brush 42, the ultrasonic vibration causes a slight horizontal vibration in the horizontal direction, and the capillary structure 31 and the support 32 receive a frictional action on the surfaces that contact each other, thereby causing local welding. To form a bond.

  The principle of the roller welding method shown in FIG. 8 is almost the same as that of spot welding, and forms a ring-shaped upper brush 46 in which a rotatable upper roller 45 is interlocked. The upper brush 46 is on a rotatable lower roller 47. Corresponds to the ring-shaped lower brush 48. During operation, the capillary structure 31 and the support body 32 are first positioned and placed between the upper and lower brushes 46, 48, the upper brush 46 is pressed downward, and the capillary structure 31 and the support body 32 are moved to the upper and lower brushes 46, 48. Hold tightly between. The upper roller 45 interlocks with the upper brush 42 and vibrates in a substantially horizontal direction due to the ultrasonic frequency, causes the surface where the capillary structure 31 and the support 32 contact each other to receive a frictional action, and causes local welding. To form a bond. Further, the capillary structure 31 and the support body 32 are moved in the lateral direction in conjunction with the upper and lower rollers 45 and 47 rotating in the opposite directions, and the purpose of continuously joining the capillary structure body 31 and the support body 32 is achieved. .

Whether spot welding or roller welding is performed using ultrasonic waves, the surfaces of the capillary structure 31 and the support 32 that come into contact with each other are rubbed, and before the local dissolution occurs due to the friction, first, The oxide formed in this step is removed by friction, and the original material is exposed on the surface. Therefore, by removing the oxide, the joint strength and tightness of the joint formed by local melting are better than those of the conventional diffusion joint, and the heat conduction resistance is further lowered and the cooling efficiency is improved. Also, the time required for ultrasonic welding is only 30 minutes, much less than the 8.9 hours required for diffusion bonding.

  In addition, joining the capillary structure 31 and the support 32 in advance using ultrasonic welding has a further cleaning effect.

  In general, during the manufacturing process of the flat plate heat pipe, it is necessary to prevent contaminants from blocking the heat pipe and affecting the processing performance. Therefore, the capillary structure 31 and the support body 32 are washed. In the manufacturing process using diffusion bonding, after the capillary structure 31 and the support 32 are cleaned, positioning is performed, and during the positioning investigation process, contaminants easily adhere and cause secondary contamination.

  The present invention replaces diffusion bonding using ultrasonic welding, and joins the capillary structure 31 and the support 32 in advance before cleaning to effectively prevent the problem of secondary contamination. .

  As described above, the capillary structure 31 is manufactured by applying the ultrasonic welding method (spot welding or roller welding), and the capillary structure 31 is joined to the support 32. In the following, the ultrasonic welding method is similarly applied, and other components of the flat plate heat pipe are further joined.

  As shown in FIGS. 3 and 9, in step 23, the joined capillary structure 31 and support 32 are joined on the lower flat plate 34 by ultrasonic welding. Since the capillary structure 31 is already joined to the support 32, the lower plate 34 can be directly positioned and joined, and the conventional capillary structure, support and lower plate can be adjusted respectively. Avoid the hassle of doing.

As shown in FIGS. 3 and 10, in step 24, the upper plate 33 having a shape corresponding to the lower plate 34 is positioned on the lower plate 34 and positioned corresponding to the heat source using ultrasonic spot welding ( For example, at least one concave portion 35 as shown in FIG. 10 is formed at a contact point with the CPU, and the upper flat plate 33 and the capillary structure 31, the support 32 and the lower flat plate 34 are coupled to each other. Between the components, strengthening the bonding density between the components, effectively preventing the components near the heat source from deforming and generating gaps, increasing the heat conduction resistance and cooling Prevents the effect from decreasing.

  As shown in FIG. 3 and FIG. 11, in step 25, roller welding is performed along the peripheral edges of the upper and lower flat plates 33, 34 using an ultrasonic roller welding method, and the upper flat plate 33 and the lower flat plate 34 are joined to each other. The structure 31 and the support 32 are sealed therein.

  Alternatively, a metal bonding layer is formed on the periphery of the upper flat plate 33, the lower flat plate 34, or the upper and lower flat plates 33, 34 using vapor phase growth, and the upper and lower flat plates 33, 34 are sealed. The upper and lower flat plates 33 and 34 can be made of a metal material such as copper or aluminum, and the metal material of the bonding layer can be selected from tin, silver, copper, and any combination thereof. The metal material may be tin, lead, or any combination of the above. Furthermore, the metal material may be tin, bismuth, or any combination of the above.

  As described above, by applying the ultrasonic welding method, the capillary structure 31, the support 32 and the upper and lower flat plates 33 and 34 are joined, the joint strength and the tightness are effectively improved, and the cooling is indirectly performed. Improve the effect. Furthermore, the time required for the joining process is greatly shortened, and the object of the present invention is reliably achieved.

In the present invention, preferred embodiments have been disclosed as described above. However, the present invention is not limited to the present invention, and any person who is familiar with the technology can use various methods within the spirit and scope of the present invention. Variations and moist colors can be added, so the protection scope of the present invention is based on what is specified in the claims.

It is a three-dimensional exploded view of a known flat plate heat pipe. It is local sectional drawing of a well-known flat plate type heat pipe. It is a flowchart of the suitable Example of the production method of the flat plate type heat pipe which applied the ultrasonic welding of this invention. It is local sectional drawing of a present Example, and a capillary structure @@ It is local sectional drawing of the said capillary structure of a present Example, and is explanatory drawing which the local part of several child capillary structure comprises the said capillary structure. It is local sectional drawing of a present Example, and is explanatory drawing which covers a support body in a ring-shaped capillary structure. It is local sectional drawing of a present Example, and is explanatory drawing which welds a capillary structure on a support body using an ultrasonic wave. It is local sectional drawing of a present Example, and is explanatory drawing which welds a capillary structure on a support body using an ultrasonic wave. It is local sectional drawing of a present Example, and is explanatory drawing which welds a capillary structure and a support body on a lower flat plate using an ultrasonic wave. It is local sectional drawing of a present Example, It is explanatory drawing which forms the recessed part which plays the role of a support between an upper flat plate and a lower flat plate using an ultrasonic wave. It is local sectional drawing of a present Example, and is explanatory drawing which joins the periphery of an upper and lower flat plate using an ultrasonic wave.

Explanation of symbols

21 to 25 Step 31 Capillary structure 311 Upper part 312 Side part 313 Lower part 314 Child capillary structure 32 Support body 321 Gap 33 Upper flat plate 34 Lower flat plate 35 Recess 41 Welding head 42 Upper brush 43 Mounting table 44 Lower brush 45 Upper roller 46 Upper Brush 47 Lower roller 48 Lower brush 21 Position the capillary structure on the support 22 Weld the capillary structure onto the support with ultrasonic waves 23 Weld the capillary structure onto the lower plate with ultrasonic waves 24 Positioning on the lower plate 25 Forming a sealed joint on the upper and lower plate edges

Claims (21)

The following steps:
(A) One surface of the capillary structure is ultrasonically bonded to any one of the upper flat plate and the lower flat plate corresponding in shape to the upper flat plate, and the capillary structure is disposed and accommodated between the upper flat plate and the upper flat plate. And the lower flat plates are stacked on top of each other,
(B) The flat plates are ultrasonically bonded to each other, and the capillary structure is sealed in a space surrounded by the flat plates.
The manufacturing method of the flat plate type heat pipe which applied ultrasonic welding characterized by comprising. The method for manufacturing a flat plate-type heat pipe according to claim 1, wherein in the step (A), the ultrasonic welding is ultrasonic spot welding. 2. The flat plate to which ultrasonic welding is applied according to claim 1, wherein in the step (A), a support is further arranged with respect to the capillary structure, and is arranged in contact with each other between the flat plates. Type heat pipe manufacturing method. 3. The method for producing a flat plate heat pipe using ultrasonic welding according to claim 2, wherein, in the step (A), the capillary structure is a piece-like body and is folded to sandwich the support. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 2, wherein in the step (A), the capillary structure is folded along both sides of the support to cover the support. 6. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 3, 4 or 5, further comprising joining at least one portion of the capillary structure to the support in the step (A). . The method of manufacturing a flat plate-type heat pipe using ultrasonic welding according to claim 6, wherein the step (A) includes joining at least one portion of the capillary structure to the support by ultrasonic welding. The method for manufacturing a flat plate heat pipe using ultrasonic welding according to claim 7, wherein in the step (A), the ultrasonic welding is one of ultrasonic spot welding, ultrasonic roller welding, and a combination thereof. The manufacturing method of the flat plate type heat pipe which applied ultrasonic welding of Claim 1 which performs ultrasonic welding along the said flat plate periphery in the said process (B), and seal-joins the said flat plate periphery. The manufacturing method of the flat plate type heat pipe which applied the ultrasonic welding of Claim 1 which performs ultrasonic roller welding along the said flat plate periphery in the said process (B), and seal-joins the said flat plate periphery. 2. The flat plate type applying ultrasonic welding according to claim 1, wherein in the step (B), a metal bonding layer is first formed on a peripheral edge of the flat plate by a vapor phase growth method to form a hermetic bond on the flat plate. Heat pipe manufacturing method. 3. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 2, wherein the support is a metal net formed by braiding metal wires. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 12, wherein the metal wire is a copper wire. 13. The flat plate heat applying ultrasonic welding according to claim 12, wherein the capillary structure is a metal net formed by braiding metal wires, and the density of the capillary structure is higher than the density of braiding of the support. Pipe manufacturing method. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 14, wherein the metal wire is a copper wire. The method for manufacturing a flat plate-type heat pipe using ultrasonic welding according to claim 1, wherein the flat plate is made of a metal material. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 16, wherein the flat metal material is selected from aluminum and copper. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 1, wherein the capillary structure includes at least two child capillary structures. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 18, wherein the sub-capillary structure is a metal net formed by braiding metal wires. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 19, wherein the metal wire is a copper wire. The method of manufacturing a flat plate heat pipe using ultrasonic welding according to claim 21, wherein the sub-capillary structure is joined using ultrasonic welding.

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