JP2008241227A - Pressure-bonded heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-bonded heat pipe of excellent heat radiating performance capable of maintaining the surface flatness of a plate-like member mounted with a cooled element without increasing the number of members in the heat pipe formed to pressure-bond the outer peripheral part of the plate-like member. <P>SOLUTION: The pressure-bonded heat pipe comprises: a container formed by arranging one container material; and the other container material to face each other and pressure-bonding the outer peripheral parts and having a sealed cavity part, a wick material arranged in the cavity part, and an operating fluid. The one container material comprises: an approximately flat outer peripheral part of flange shape; an approximately flat center part with a level difference from the outer peripheral part; and a sidewall part connecting the outer peripheral part to the center part, while the other container material comprises: an approximately flat outer peripheral part of flange shape; an approximately flat center part with a level difference from the outer peripheral part; a sidewall part connecting the outer peripheral part to the center part; and a plurality of recesses depressed from the center part toward the center part of the one container material and having the end of curved surface shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure welding type heat pipe suitable for cooling an element to be cooled, such as a semiconductor chip or the like, which has a high calorific value.

  Electronic parts such as semiconductor elements mounted on electric / electronic devices such as personal computer CPUs, laser light-emitting diodes, and power transistors generate heat due to their use and need to be cooled. As a method for cooling an electronic component such as a semiconductor element that requires cooling, for example, a method for lowering the temperature of air in a device casing by attaching a fan to the device, or by attaching a cooling body to the element to be cooled, A method for directly cooling the battery is known. As a cooling body attached to the element to be cooled, for example, a plate material made of a material having excellent heat conductivity such as a copper material or an aluminum material, or a plate heat pipe is often used.

  A space serving as a flow path for the working fluid is provided inside the heat pipe, and the working fluid accommodated in the space undergoes a phase change or movement such as evaporation or condensation, thereby transferring heat. That is, on the heat absorption side of the heat pipe, the working fluid evaporates due to the heat generated by the parts to be cooled that are conducted through the material of the container constituting the heat pipe, and the vapor moves to the heat radiation side of the heat pipe. To do. On the heat radiating side, the working fluid vapor is cooled and returned to the liquid phase again. The working fluid that has returned to the liquid phase in this way moves (refluxs) again to the heat absorption side. Heat is transferred by such phase transformation and movement of the working fluid. In order to increase the cooling efficiency, it is necessary to maintain the flatness of the surface to which the element to be cooled is attached.

  The plate-type heat pipe container is formed by a method in which two plate-shaped members formed by pressing or the like are joined by brazing (for example, Japanese Patent Laid-Open No. 10-38484), pressure welding that is mechanically deformed at room temperature. A method (Japanese Patent Laid-Open No. 2002-310581) is known.

  Unlike heat pipes that are joined by brazing, the heat pipe that joins the periphery by pressure welding does not require the use of joining members. Further, since bonding at normal temperature is possible, it is possible to press-contact with the hydraulic fluid held inside, and the container forming and hydraulic fluid filling steps, which were impossible with brazing, can be made the same step. That is, a low-cost heat pipe can be realized in terms of member saving and process saving, and pressure welding is particularly attracting attention as a method for producing a plate heat pipe.

When the container is to be pressure welded, the elongation of the pressure welded joint deforms the center of the container. In particular, it is known that the container is recessed in the direction of the internal space.
In addition, when it press-contacts in the state without a supporting member, even when the inside of a container is the same as atmospheric pressure, a container is similarly dented at the time of press-contact. Therefore, the well-known reinforcement structure for preventing the heat pipe from being crushed from the pressure difference between the inside and outside of the container and the support structure described here are essentially different, and are structures unique to the pressure welding system.

In order to prevent deformation of the container, a method of disposing a columnar member inside the container is disclosed (Japanese Patent Laid-Open No. 2006-313033). That is, as shown in FIG. 7, when the upper plate material 102 and the lower plate material 103 corresponding to each other are arranged to face each other, the columnar members 104 and 105 are arranged in the formed cavity, and the outer surface is pressed against the flat surface of the container. Is not deformed. There is also a method of embossing instead of the container. That is, as shown in an enlarged view in FIG. 8, the embossing 106 is applied to the lower plate material 103 that faces the upper plate material 102.
JP 10-38484 A Japanese Patent Laid-Open No. 2002-310581 JP 2006-313033 A

When using a support member as described with reference to FIG. 7, there are problems that the number of members increases and that it is necessary to further provide a means for positioning the support member in the container.
As described with reference to FIG. 8, when embossing a container on one side, it is necessary to squeeze deeply until it reaches the opposite container. There is a limit to the amount. As a result, there was a problem that the space in the heat pipe had to be lowered, and the performance of the heat pipe was lowered.

  As shown in FIG. 9, if embossing 106 is applied to both containers and the surface at the tip of the dent is brought into contact, the space in the heat pipe can be made thicker than when only one side is squeezed, In the case of cooling by attaching the fin 109 to the heat pipe, as shown in FIG. 9B, a cavity is formed between the fin 109 and the embossed portion 106, and the efficiency of heat transfer from the heat pipe 101 to the fin 109. There was a problem of falling.

  Therefore, the object of the present invention is to maintain the flatness of the surface of the plate-like member to which the element to be cooled is attached without increasing the number of members in the heat pipe that press-joins the outer peripheral portion of the plate-like member. An object of the present invention is to provide a pressure welding heat pipe excellent in heat dissipation performance.

  The inventor conducted extensive research to solve the conventional problems. As a result, when one container material arranged oppositely is pushed down from the central portion toward the central portion of the other container material and has a plurality of hollow portions with curved ends, the two container materials It was found that even if the outer peripheral portions are joined by pressure welding, no deformation occurs in the central portion.

  In particular, it is more effective when the above-mentioned concave portion having a curved tip is provided in the vicinity of the side wall portion of the container and is formed deeper toward the container material facing the joint surface of the outer peripheral surface. found. The present invention has been made based on the research results described above.

A first aspect of the pressure welding heat pipe according to the present invention includes a substantially flat outer peripheral portion having a flange shape, a substantially flat central portion having a step with the outer peripheral portion, and a side wall connecting the outer peripheral portion and the central portion. One container material provided with a section,
A flange-shaped substantially flat outer peripheral portion, a substantially flat central portion having a step with the outer peripheral portion, a side wall portion connecting the outer peripheral portion and the central portion, and the center of the one container material from the central portion A container having a sealed cavity formed by pressing the outer peripheral portion together by press-contacting the other container material provided with a plurality of hollow portions with curved ends at the front end When,
It is a pressure welding type heat pipe provided with the wick material and hydraulic fluid which are arranged in the hollow part.

  According to a second aspect of the pressure welding type heat pipe of the present invention, when the hollow portion presses the outer peripheral portion of the one container material and the outer peripheral portion of the other container material, the one container material and / or Or it is a pressure welding type heat pipe provided in the predetermined position of the vicinity of the said side wall part which can prevent the deformation | transformation of the said center part of said other container material.

  According to a third aspect of the pressure welding type heat pipe of the present invention, the hollow portion formed in the other container material is formed deeper toward the one container material than the joining surface of the outer peripheral portion. It is a pressure welding type heat pipe.

  A fourth aspect of the pressure welding heat pipe according to the present invention is a pressure welding heat pipe in which a taper is provided on a side surface of the depression so that a tip of the depression is thinner than a base.

  A fifth aspect of the pressure welding type heat pipe of the present invention is a pressure welding type heat pipe in which the tip of the recess is in contact with a wick material arranged on the inner surface of the opposing container material.

  A sixth aspect of the pressure welding type heat pipe of the present invention is a pressure welding type heat pipe in which the tip of the recess is a rotationally symmetric curved surface.

  A seventh aspect of the pressure welding type heat pipe of the present invention is a pressure welding type heat pipe in which heat radiation fins are provided in one container material on the side facing the other container material having the hollow portion.

According to the pressure welding type heat pipe of the present invention, the pressure welding type heat pipe excellent in heat dissipation performance can maintain the flatness of the surface of the plate-like member to which the element to be cooled is attached without increasing the number of members. can get.
That is, since one container material arranged oppositely is pushed down from the central portion toward the central portion of the other container material and has a plurality of hollow portions with curved ends, the two container materials Even when the outer peripheral portions are arranged so as to face each other and are joined by pressure welding, the flatness can be maintained because the central portion is not deformed.

  Furthermore, if the above-mentioned concave portion having a curved tip is provided in the vicinity of the side wall portion of the container and is formed deeper toward the container material opposed to the joint surface of the outer peripheral surface, the deformation of the central portion is more effective. Therefore, the flatness of the surface of the plate member to which the element to be cooled is attached can be maintained, and the heat radiation performance is excellent.

A pressure welding heat pipe according to the present invention will be described with reference to the drawings.
One aspect of the pressure welding heat pipe of the present invention includes a substantially flat outer peripheral portion having a flange shape, a substantially flat central portion having a step difference from the outer peripheral portion, and a side wall portion connecting the outer peripheral portion and the central portion. One container material, a flange-shaped substantially flat outer peripheral part, a substantially flat central part having a step with the outer peripheral part, a side wall part connecting the outer peripheral part and the central part, and one container material from the central part. A container provided with a sealed cavity formed by pressing down toward the center part and opposingly arranging the other container material provided with a plurality of hollow parts with curved ends at the tip, and joining the outer peripheral part by pressure welding And a pressure welding type heat pipe provided with a wick material and a working fluid disposed in the cavity.

  Fig.1 (a) is the top view seen from the container material side in which the hollow part was formed explaining the one aspect | mode of the pressure welding type heat pipe of this invention. FIG.1 (b) is the elements on larger scale of the AA cross section of Fig.1 (a). As shown in FIG. 1 (a), two container members 2 each having a flange-shaped substantially flat outer peripheral portion 4, a substantially flat central portion 8, and a side wall portion 5 connecting the outer peripheral portion 4 and the central portion 8. 3 is disposed so as to have a sealed cavity inside, and the outer peripheral portion 4 is press-welded. One container material 2 includes a plurality of depressions 6 having a curved tip 7 near the side wall 5. The depression 6 is pushed down toward the center of the other container material 3.

  FIG.1 (b) is the elements on larger scale of the AA cross section of Fig.1 (a). As shown in FIG. 1B, a recess 6 is formed in the vicinity of the side wall 5 of one container material 2. The recess 6 is formed so that the tip 7 is a curved surface, preferably a rotationally symmetric curved surface, so that stress applied to the container surface during embossing is dispersed. As a result, breakage at the tip can be prevented. Furthermore, it is preferable that the hollow portion is formed so that the tip portion and the root portion are not substantially the same size as described in the prior art, and the tip portion is narrower than the root portion. The amount of deformation (angle) can be reduced, and breakage at the root portion can be prevented.

  The shape of the curved surface of the dent is not particularly limited as long as it is intended that stress is not concentrated on a part when the dent is formed. For example, it includes a shape in which a flat portion remains in a part of what is mostly composed of a curved surface. Further, in order to evenly distribute the stress applied to the depressions and considering the ease of molding, a rotationally symmetric shape, more preferably a spherical surface, is preferable.

  Furthermore, as shown in FIG.1 (b), the hollow part 6 formed in one container material 2 is deeply formed toward the other container material rather than the joining surface of an outer peripheral part. That is, the tip of the curved surface of the recess formed toward the other container material is formed so as to be pressed deeper than the joint surface of the outer peripheral portion without contacting the central portion of the other container material.

  FIG. 2 is a partially enlarged view of the AA cross section shown in FIG. 1A of the heat pipe of another embodiment. In this embodiment, a tapered portion 9 is provided on the side surface of the tip portion 7 of the recessed portion 6. In other words, the tip 7 is a spherical surface and the side is a tapered portion (slightly sloped surface) 9. By providing the tapered portion on the side as described above, the tip can be made thinner than the root. Furthermore, the bending of the root portion can be made 90 degrees or less, and the stress applied to the root portion can be relaxed.

  According to this aspect, it is possible to relieve stress applied to the root portion and the tip portion, and to form a deeper depression. The tapered portion on the side surface of the distal end portion is easier to understand than the recessed portion described with reference to FIG. In the hollow portion shown in FIG. 1, the angle of the root portion is close to 90 degrees and is considerably large. On the other hand, in the hollow portion shown in FIG. 2, the angle of the root portion is approximately 45 degrees and slightly smaller.

  For example, a C1100 plate with a thickness of 0.5 mm is squeezed 1.8 mm to form a flange portion, a central portion, and a side wall portion, and the tip has a spherical surface with a radius (R) of 2 mm, and the opening is Φ6 By pressing the central portion with a female die having a diameter, a hollow portion deeper than the flange portion having a depth of 2.6 mm can be formed without breaking the container material.

  FIG. 3 is a partial cross-sectional view of a container including a recess after vacuum pressure welding. As shown in FIG. 3, one container material 2 of the two container materials 2, 3 arranged to face each other is pushed down from the central portion 8 toward the central portion of the other container material 3, and the tip is curved. The outer peripheral part 5 of the two container materials 2 and 3 is joined by pressure welding. A wick material such as a mesh is arranged along the inner wall of the central portion of the other container material of the sealed cavity formed by the two container materials.

Fixing the wick material to the container inner wall is facilitated by making the distance between the tip of the recess and the inner wall of the container material facing the pit material substantially the same as the thickness of the wick material. In addition, by forming a recess so as to provide a space between the opposing container inner wall and the tip, it is possible to prevent the wick material from hanging down and block the flow path, so that sufficient space in the heat pipe is secured. Can do. Moreover, since friction arises between the container material which opposes via a wick at the time of pressure welding, and a hollow part, the container material which opposes becomes difficult to slide on a hollow. Therefore, by putting a wick material, it is possible to more effectively prevent stress from being applied to the central portion of the container and further increase the effect of preventing deformation of the container.
As shown in FIG. 3, since the mesh is held at the tip of the curved surface of the depression, the area where the mesh is blocked is reduced compared to holding the mesh on a flat surface, which is advantageous.

  FIG. 4 is a partial cross-sectional view illustrating a state where the fin portion is thermally connected to the container. As shown in FIG. 4, the fin part is joined to the surface of the container material in which the hollow part is not formed. Since the surface of the container material on which the hollow portion is not formed is substantially flat, no cavity is generated between the container material and the fin portion, and heat can be efficiently transferred.

  FIG. 5 is a partial cross-sectional view illustrating a state in which a heat transfer block is provided inside the container and a wick material is disposed on each inner wall of the two container materials. As shown in FIG. 5, the heat of the heating element 13 is finned by being thermally connected to both the container materials 2, 3 at the approximate center of the cavity formed by arranging the two container materials 2, 3 to face each other. A heat transfer block 12 that moves directly to the container material 3 to which the part 11 is joined is disposed.

  The heat transfer block is preferably arranged so as to cover the same area as the heat generating element or a slightly larger area than the cross-sectional area of the heat generating element. For example, if the heat transfer block is made of C1020 material and annealed in a high-temperature reducing atmosphere before pressure welding, it is strongly sandwiched between the inner wall surfaces of the two container materials facing each other when the outer periphery is pressure-welded. Thus, the heat transfer block itself is slightly deformed and closely contacts the inner wall of the container material without deforming the central portion of the container material.

  FIG. 6 is a partial cross-sectional view for explaining a state in which a wick material is arranged on each inner wall surface of two container materials arranged to face each other and a wick holding member for fixing the wick material is arranged. As shown in FIG. 6, the heat of the heating element 13 is finned by being thermally connected to both the container materials 2 and 3 at the approximate center of the cavity formed by arranging the two container materials 2 and 3 to face each other. A heat transfer block 12 that moves directly to the container material 3 to which the part 11 is joined is disposed.

  A wick material 10 is disposed along the inner wall surface of the container material 2 and the inner wall surface of the container material 3. The wick material 10 arranged along the inner wall surface of the container material 3 is fixed by the tip of the hollow portion 6. Furthermore, the wick material 10 disposed along the inner wall surface of the container material 2 and the inner wall surface of the container material 3 is fixed by a wick holding member 14. The wick holding member 14 is preferably formed, for example, by bending a copper mesh and does not completely obstruct the flow of steam in the cavity inside the container.

  Thus, by arranging the wick holding member, the wick material is stably held on the inner wall surface of the container, and the capillary force between the container inner wall surface and the wick member can be utilized. By increasing the capillary force, a heat pipe that operates more stably even in the top heat mode can be obtained.

As described above, the pressure welding type heat pipe of the present invention is pushed down by one container material opposed to the central portion of the other container material from the center portion, and has a plurality of curved ends. Since the hollow portion is provided, the two container materials are arranged to face each other, and even if the outer peripheral portion is joined by pressure welding, the central portion is not deformed. Furthermore, when the above-mentioned concave portion having a curved tip is provided in the vicinity of the side wall portion of the container and is formed deeper toward the container material facing the joint surface of the outer peripheral surface, the prevention of deformation is more effective. To be done.

Fig.1 (a) is the top view seen from the container material side in which the hollow part was formed explaining the one aspect | mode of the pressure welding type heat pipe of this invention. FIG.1 (b) is the elements on larger scale of the AA cross section of Fig.1 (a). FIG. 2 is a partially enlarged view of the AA cross section shown in FIG. 1A of the heat pipe of another embodiment. FIG. 3 is a partial cross-sectional view of a container including a recess after vacuum pressure welding. FIG. 4 is a partial cross-sectional view illustrating a state where the fin portion is thermally connected to the container. FIG. 5 is a partial cross-sectional view illustrating a state in which a heat transfer block is provided inside the container and a wick material is disposed on each inner wall of the two container materials. FIG. 6 is a partial cross-sectional view for explaining a state in which a wick material is arranged on each inner wall surface of two container materials arranged to face each other and a wick holding member for fixing the wick material is arranged. FIG. 7 is a cross-sectional view illustrating a conventional heat pipe in which a columnar member is disposed between an upper plate material and a lower plate material. FIG. 8 is a partially enlarged cross-sectional view for explaining a conventional heat pipe subjected to embossing. FIG. 9 is a cross-sectional view illustrating a state where the fin portion is attached to the embossed container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure welding type heat sink 2 Container material 3 Container material 4 Outer peripheral part 5 Side wall part 6 Depression part 7 Tip part 8 Center part 9 of container material Side surface (taper part) of a depression part
10 Wick Member 11 Fin 12 Heat Transfer Block 13 Heating Element 14 Wick Holding Member

Claims (7)

One container material comprising a flange-shaped substantially flat outer peripheral portion, a substantially flat central portion having a step with the outer peripheral portion, and a side wall portion connecting the outer peripheral portion and the central portion,
A flange-shaped substantially flat outer peripheral portion, a substantially flat central portion having a step with the outer peripheral portion, a side wall portion connecting the outer peripheral portion and the central portion, and the center of the one container material from the central portion A container having a sealed cavity formed by pressing the outer peripheral portion together by press-contacting the other container material provided with a plurality of hollow portions with curved ends at the front end When,
A pressure welding heat pipe comprising a wick material and a working fluid disposed in the cavity.   When the said recessed part press-contacts the outer peripheral part of said one container material, and the outer peripheral part of said other container material, a deformation | transformation of the said center part of said one container material and / or said other container material is prevented. The pressure welding type heat pipe according to claim 1, which is provided at a predetermined position in the vicinity of the side wall portion.   The pressure welding type heat pipe according to claim 1 or 2, wherein the hollow portion formed in the other container material is formed deeper toward the one container material than a joining surface of the outer peripheral portion.   The pressure welding type heat pipe according to any one of claims 1 to 3, wherein a taper is provided on a side surface of the recess so that a tip of the recess is thinner than a base.   The pressure welding type heat pipe of any one of Claim 1 to 4 with which the front-end | tip of the said hollow part is contacting the wick material arrange | positioned at the inner surface of the container material which opposes.   The pressure welding type heat pipe according to any one of claims 1 to 5, wherein a tip of the recess is a rotationally symmetric curved surface. The pressure welding type heat pipe according to any one of claims 1 to 6, wherein heat radiation fins are provided in one container material on the side facing the other container material having the hollow portion.

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