Heat pipe and heat sink joint structure and cooling module

Abstract

Provided is a heat pipe and heat sink joining structure and cooling module that can stably perform soldering using a paste solder containing an oxide film removing flux with a simple structure. The heat sink (2) of the present invention joins a metal heat pipe (5) and an aluminum heat sink (6) using a paste solder (25) containing an oxide film removing flux, and is configured so that the heat sink (6) has a plurality of protrusions (22) on the face, i.e., the upper edge portion (15b), that joins the heat pipe (5), the top portions (22a) of the plurality of protrusions (22) each contact the heat pipe (5), and the paste solder (25) is located at least in the space formed by the heat pipe (5), the upper edge portion (15b), and the plurality of protrusions (22) and joins the heat pipe (5) and the heat sink (6).

Description

Technical Field

[0001] The present invention relates to a connection structure of a metal heat pipe for conducting heat from a heat-generating component and an aluminum heat sink for releasing the received heat, as well as a cooling module. Background Technology

[0002] Conventionally, in such bonding structures, a plating portion or coating of copper (Cu) or tin (Sn) for improving solderability is formed on a heat transfer member made of aluminum, and the heat pipe is bonded to the plating portion or coating (e.g., Patent Document 1). However, in recent years, due to environmental restrictions, there has been a tendency to impose restrictions, including the abolition, on electroplating processes. Therefore, Patent Document 2 shows a structure in which a heat transfer member 104 is bonded to a first heat dissipation section 103 by melting a paste solder. An embedding groove 103a is formed on the surface of the plate-shaped first heat dissipation section 103 made of aluminum or the like, and the heat transfer member 104, for example, a heat pipe, is embedded in the embedding groove 103a. The heat is then heated in a reflow oven with the paste solder disposed between the heat transfer member 104 and the embedding groove 103a. Here, the paste solder is generally a paste solder containing flux that removes the oxide film, and includes granular solder and liquid flux.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2005-344984 Patent Document 2: Japanese Patent Application Publication No. 2020-181930 To bond the paste solder to aluminum components, the activator contained in the flux is needed to reduce the oxide film formed on the surface of the aluminum component. A specified amount of activator is required, thus increasing the amount of flux in the paste solder and reducing its viscosity. Therefore, if a paste solder containing flux that removes the oxide film in this bonding structure is used for soldering, there are problems such as solder potentially flowing outside the bonding area, unstable solder quantity, and potential variations in the mechanical strength or thermal resistance of the bonding area. To address this problem, Patent Document 2 describes a heat dissipation structure with an embedding groove 103a for embedding the heat transfer member 104; however, a simpler structure is desired. Summary of the Invention

[0004] Therefore, in view of the above, the object of the present invention is to provide a heat pipe and radiator connection structure and a cooling module that can stably implement soldering using a paste solder containing flux that removes oxide film with a simple structure.

[0005] The heat pipe and radiator joining structure of the present invention uses a paste solder containing flux to remove oxide film to join a metal heat pipe to an aluminum radiator. The radiator is characterized in that the radiator has a plurality of protrusions on the side where it joins the heat pipe, the tops of the plurality of protrusions are in contact with the heat pipe, and the solder is located at least in the space formed by the heat pipe, the side surface and the plurality of protrusions and joins the heat pipe and the radiator.

[0006] Invention Effects According to the present invention, welding using a paste solder containing flux that removes oxide film can be stably carried out with a simple structure. Attached Figure Description

[0007] Figure 1 (A) is a rear view schematically showing a structural example of a cooling module according to one embodiment of the present invention, and (B) is a top view schematically showing a structural example of a cooling module.

[0008] Figure 2 Same as above, is Figure 1 CC section view.

[0009] Figure 3 Same as above, is Figure 1 DD sectional view.

[0010] Figure 4 As above, this is a 3D view of the radiator.

[0011] Figure 5 Same as above, is Figure 4 Enlarged view of frame E.

[0012] Figure 6 Similarly, this is a schematic diagram illustrating the assembly sequence of the cooling module.

[0013] Figure 7 This is a cross-sectional view of the heat sink, heat pipe, and components of a cooling module, representing a modified embodiment of the present invention.

[0014] Figure 8 This is a cross-sectional view of the heat sink, heat pipe, and components of a cooling module, illustrating another variation of an embodiment of the present invention.

[0015] Explanation of reference numerals in the attached figures 2, 2', 2" receiver (joint construction) 5 heat pipes 6. 6' radiator 15b Top part (one side of the face) 15c lower edge (the other side of the face) 22 protuberance 22' Protrusion (Protrusion for Components) 22a top 25. Paste solder (solder) 31 components 35 components 35a flat surface 36. Protrusions (protrusions for heat pipes) Detailed Implementation

[0016] Hereinafter, a preferred embodiment of the cooling module 1 of the present invention will be described with reference to the accompanying drawings.

[0017] Figures 1-6 This illustrates one embodiment of the cooling module 1 of the present invention. Figure 1 This is a schematic diagram illustrating the structure of cooling module 1; (A) shows the rear view, and (B) shows the front view. Additionally, Figure 2 express Figure 1 CC section view, Figure 3 express Figure 2 The DD cross-sectional view is shown. Referring to these figures, the cooling module 1 is configured as having a heat absorber 2 that absorbs heat from heat-generating components such as a microprocessor, and a fan 3 that serves as an air supply mechanism for promoting heat dissipation from the heat absorber 2. The heat absorber 2 in this embodiment includes: a heat receiving part 4, which is mounted in close contact with the heat-generating component; a heat pipe 5, which serves as a heat transfer part, has the heat receiving part 4 mounted at one end and is thermally connected to the heat receiving part 4; and a heat sink 6, which is mounted at the other end of the heat pipe 5 and is thermally connected to the heat pipe 5, receives heat from the heat pipe 5, and discharges the heat of the cooling module 1 to the outside by exchanging heat with the air blown from the fan 3.

[0018] The fan 3 in this embodiment is an axial flow fan that draws in ambient air axially and supplies cooling air toward the radiator 6. It is configured to have fan blades 3-1 that form the blade section, a fan motor 3-2 that rotates the fan blades 3-1, and a housing 3-3 and a cover 3-4 that constitute a frame housing the fan blades 3-1 and the fan motor 3-2. The housing 3-3 and the cover 3-4 have through holes, namely air intake 11 and air intake 12, provided with reference to the central part of the part where the fan blades 3-1 and the fan motor 3-2 are arranged. In addition, the housing 3-3 and the cover 3-4 are configured to have one of their square side walls open, and this opening is formed as an air outlet 13 when assembling the frame.

[0019] The heated part 4 transfers heat from the heating element to the heat pipe 5, and is made of a metal with high thermal conductivity, such as copper or aluminum. In addition, in the cooling module 1 of this embodiment, heat from the heating element is transferred to the heat pipe 5 via the heated part 4. However, this is just one example. It is also possible to configure the heating element to be in direct contact with the heat pipe 5, so that heat from the heating element is directly transferred to the heat pipe 5.

[0020] Heat pipe 5 is a heat-conducting component that injects a working fluid into a metal tube with excellent thermal conductivity and allows the working fluid to circulate back within the tube. In this embodiment, heat pipe 5 employs a structure where a mesh-like metal core and a small amount of working fluid, such as pure water, are sealed inside a hollow copper tube, creating a vacuum inside. The lower surface 5a and upper surface 5b (see reference) Figure 8 The core is formed into a flat, flat shape, which provides excellent thermal response. Alternatively, it can be configured with fine grooves on the inner wall of the tube instead of the core. When heat is conducted to one end of the heat pipe 5 and heated, the liquid in the heated portion evaporates into a gas, thus absorbing the conducted heat as latent heat. The gas then moves to the other end of the tube, which is located on the opposite side. Since the other end of the tube is at a lower temperature, the moving gas condenses and returns to liquid, releasing the heat absorbed during condensation to the other end of the tube. In this way, heat conduction occurs between the two ends of the heat pipe 5. Furthermore, the invention is not limited to this; for example, carbon fiber or other raw materials can be used instead of copper, and a heat-dissipating metal plate can be used instead of the heat pipe 5.

[0021] Figure 4 This is a 3D view of radiator 6. Figure 5 express Figure 4 Enlarged views are shown. Referring to these figures, the heat sink 6 is plate-shaped and consists of multiple heat sink fins 15, 15... The heat sink fins 15 are made of aluminum, a metal with excellent thermal conductivity. In this embodiment, it is made of unplated aluminum, but this is just one example; it could also be made of an aluminum alloy. Figure 1 As shown, the radiator 6 is installed at the air outlet 13 of the housing 3-3 and the cover 3-4. The air intake 6a installed at the air outlet 13 of the radiator 6 has a shape that is approximately the same as that of the air outlet 13, and is configured such that all the air from the air outlet 13 flows through the air intake 6a through the radiator 6.

[0022] The heat sink 15 has a flat body 15a, a flat upper side 15b on one side of the body 15a, and a flat lower side 15c on the other side of the body 15a. These multiple heat sinks 15, 15… are arranged parallel to each other on the flat surface 21 of the body 15a. The upper side 15b and the lower side 15c extend in a direction perpendicular to the flat surface 21, and the cross-section of the heat sink 15 is approximately U-shaped. Therefore, the length of the upper side 15b from the flat surface 21 (i.e., the width of the upper side 15b) and the length of the lower side 15c from the flat surface 21 (i.e., the width of the lower side 15c) are approximately the same, but this is only one example. Furthermore, by arranging the multiple heat sinks 15, 15… parallel to each other, a heat sink 6 is constructed.

[0023] 22, 22 are protrusions formed in the heat sink 15 that protrude upwards from the upper side 15b towards the main body 15a on the surface where they join the heat pipe 5. 25 is a paste-like solder that joins the heat pipe 5 to the heat sink 6. Furthermore, the surface between the protrusions 22, 22 of the upper side 15b is a mounting portion 26. The paste-like solder 25 is at least disposed within the space formed by the lower surface 5a of the heat pipe 5, the protrusions 22, 22, and the mounting portion 26 of the upper side 15b, thereby creating a structure that joins the heat pipe 5 and the heat sink 6.

[0024] In this embodiment, the protrusion 22 has a generally trapezoidal cross-section and is formed throughout the width of the upper portion 15b. The heat pipe 5 is mounted on the heat sink 15 with its top 22a, located at the top of the trapezoid, in contact with the heat pipe 5. Therefore, heat from the heat pipe 5 can be received directly from the upper portion 15b not only through the solder paste 25 but also through the top 22a, thereby improving thermal conductivity. In addition, the protrusion 22 has the function of retaining the solder paste 25 on the mounting portion 26 to prevent the solder paste 25 from flowing to other parts, and also functions as a solder holding mechanism. Furthermore, the height of the protrusion 22 is preferably about 0.1 to 1.0 mm. In this embodiment, the protrusion 22 is formed to be about 0.2 mm, but this is just an example. The height of the protrusions 22 and the spacing between them can also be determined based on conditions such as the joint area between the heat pipe 5 and the heat sink 6, the amount of solder paste 25 required to join the heat pipe 5 and the heat sink 6, and the type of solder paste 25 used. Furthermore, in this embodiment, the protrusion 22 is designed with a roughly trapezoidal cross-section for ease of processing. However, the present invention is not limited to this shape. For example, the protrusion 22 may be hemispherical, semi-cylindrical (semi-cylindrical), cuboid, conical, or triangular pyramidal. The contact area of ​​the top 22a, which contacts the lower surface 5a of the heat pipe 5, can also be determined based on conditions such as the thermal conductivity from the heat pipe 5 to the radiator 6. In addition, in this embodiment, the protrusion 22 is formed at approximately the same position as the upper edge 15b, such as... Figure 4 and Figure 5 As shown, when multiple heat sinks 15, 15... are arranged parallel to each other, the protrusions 22, 22 are configured to form multiple rows in a straight line along the entire width of the heat sink 6. However, the present invention does not necessarily require the protrusions 22 to be continuous. For example, heat sinks 15 that require multiple molds but have protrusions 22 and heat sinks 15 that do not have protrusions 22 can be combined to form a configuration of protrusions 22 that appears staggered or discontinuous when viewed from above as the completed state of the heat sink 6. In this case, the protrusions 22 also function as a solder holding mechanism that retains the solder paste 25 in the space formed by the four protrusions 22 located at the far ends in the width and length directions in the upper side 15b, the upper side 15b, and the heat pipe 5.

[0025] The paste solder 25 is a paste solder containing flux that removes the oxide film from aluminum. In this embodiment, it is a paste mixture composed of granular solder and liquid flux. The flux used is a mixture of resin, solvent, activator, etc. Furthermore, the activator used is specific to aluminum materials in order to reduce the oxide film on the surface of the aluminum heat sink 6. To reduce the oxide film on the surface of the heat sink 6, a certain amount of activator needs to be present in the flux of the paste solder 25. However, if the proportion of flux in the paste solder 25 is too high, the heavier solder particles will precipitate downwards, causing separation as the flux components move upwards. Therefore, the flux ratio cannot be excessively increased. In this embodiment, the flux:solder ratio is set to approximately 5:1 by volume. However, due to the use of flux, the viscosity is lower than that of ordinary solder. Therefore, in this embodiment, the paste solder 25 is placed on the mounting portion 26 until it is heated and bonded to the heat pipe 5 and the radiator 6. The protrusions 22, 22 retain the paste solder 25 on the mounting portion 26, allowing sufficient activator to be supplied to the surface of the mounting portion 26, which serves as the bonding area of ​​the radiator 6, to reduce the oxide film. Furthermore, the present invention is not limited to this configuration; the volume ratio of flux to solder in the paste solder 25 of this embodiment is just one example.

[0026] Next, refer to Figure 6 The assembly of the cooling module 1 will be described as follows: As shown in (1) of (I), the heat pipe 5 is joined to the heat sink 6 using solder paste 25. First, multiple heat sink fins 15, 15... are arranged in parallel to each other to form the heat sink 6. Then, solder paste 25 is applied to the lower surface 5a of the heat pipe 5.

[0027] Furthermore, in this state of the heat sink 6, the heat pipe 5 is arranged such that the lower surface 5a of the heat pipe 5 contacts the top 22a of the protrusion 22. In this case, the protrusion 22 functions as a solder holding mechanism that keeps the paste solder 25 in the space formed by the plurality of protrusions 22, 22..., the upper part 15b and the heat pipe 5.

[0028] Alternatively, solder paste can be applied to both the mounting portion 26 of the heat sink 15 and the lower surface 5a of the heat pipe 5. In this state, the heat pipe 5 is arranged in the heat sink 6 such that the lower surface 5a of the heat pipe 5 contacts the top 22a of the protrusion 22. In this case, the protrusion 22 also functions as a solder holding mechanism to retain the solder paste 25 in the space formed by the plurality of protrusions 22, 22..., the upper portion 15b, and the heat pipe 5.

[0029] Then, after the heat pipe 5 is installed, it is heated, for example by a reflow oven, thereby connecting the heat pipe 5 to the radiator 6.

[0030] Next, as shown in (2) of (I), the heated portion 4 is joined to the other end of the heat pipe 5. The joining of the heat pipe 5 and the heated portion 4 can also be welding. In this case, (1) and (2) can also be performed simultaneously by arranging the radiator 6, the heat pipe 5, and the heated portion 4 and heating them simultaneously using a reflow oven or the like. The radiator 6, the heat pipe 5, and the heated portion 4 are joined together to form the absorber 2. Then, as shown in (3) of (I), the cover 3-4 is installed on the absorber 2 and it is transferred to (II).

[0031] In (II), firstly, a fan motor 3-2 is mounted on the housing 3-3, and a fan blade 3-1 is mounted on the fan motor 3-2. Then, as shown in (4), the radiator 6 in this state is clamped by the housing 3-3 and the cover 3-4 in the structure shown in (A) and (B) of (II), and the housing 3-3 and the cover 3-4 are combined such that the radiator 6 is clamped at the air outlet 13. The fan 3 is then assembled as shown in (III), thereby forming the cooling module 1. Furthermore, the assembly sequence and structure described herein are only one example, and the invention is not limited thereto.

[0032] As described above, the heat absorber 2 configured as the joint structure of the heat pipe 5 and the heat sink 6 in this embodiment is a structure in which the metal heat pipe 5 and the aluminum heat sink 6 are joined using a paste solder 25. The paste solder 25 is a paste solder containing flux to remove the oxide film. The heat sink 6 has a plurality of protrusions 22 on the upper edge 15b of the side that serves as the joint surface of the heat pipe 5. The tops 22a of the plurality of protrusions 22 are in contact with the heat pipe 5. The paste solder 25 is located at least within the space formed by the heat pipe 5, the upper edge 15b and the plurality of protrusions 22, and is joined with the heat pipe 5 and the heat sink 6.

[0033] With this configuration, the paste solder 25 is located between the protrusions 22, 22, and can remain on the mounting portion 26 without flowing out of it, thus enabling stable soldering using the paste solder 25 with reduced viscosity.

[0034] In addition, the cooling module 1 of this embodiment is configured to include a heat absorber 2 and a fan 3 as an air supply mechanism for blowing cooling air to the heat sink 6, which can efficiently cool the heat absorber 2.

[0035] Figure 7 This illustrates a variation of the cooling module 1' in this embodiment. In this variation, in addition to the upper 15b of the heat sink 15' of the heat sink 6' of the heat absorber 2', protrusions 22', 22' are also formed on the lower 15c, and the lower 15c is joined to the aluminum component 31 using solder paste 25.

[0036] Referring to the figure, 31 is, for example, an aluminum component such as a heat-receiving part that receives heat from a heat-generating component. The flat portion of component 31, i.e., the flat surface 31a, is joined to the heat sink 6'. Additionally, 22' and 22' are protrusions formed in the heat sink 15' that are joined to component 31, i.e., the lower edge 15c, protruding downwards towards the other side of the main body 15a. Furthermore, the surface between the protrusions 22' and 22' of the lower edge 15c is a mounting portion 26'. Solder paste 25 is at least disposed within the space formed by the flat surface 31a of component 31, the protrusions 22' and 22', and the mounting portion 26' of the lower edge 15c, thus creating a structure that joins with both component 31 and the heat sink 6.

[0037] In this embodiment, the protrusion 22' has a generally trapezoidal cross-section and is formed throughout the width direction of the lower side 15c. The component 31 is mounted on the heat sink 15 with the top 22'a of the upper side of the trapezoid in contact with the component 31. The protrusion 22' has the function of retaining the paste solder 25 on the mounting part 26' to prevent the paste solder 25 from flowing to other parts, and also functions as a solder holding mechanism.

[0038] As described above, the heat absorber 2' configured as the joint structure of the heat pipe 5 and the heat sink 6' in this embodiment includes an aluminum element 31 that is joined with the heat sink 6'. The heat sink 6' has a plurality of protrusions 22', 22' on the lower edge 15c of the side that serves as the joint element 31, i.e. the other side. The tops 22'a of the plurality of protrusions 22', 22' are in contact with the element 31. The solder paste 25 is located at least in the space formed by the element 31, the lower edge 15c and the protrusions 22', 22' and is joined with the element 31 and the heat sink 6'.

[0039] With this configuration, the paste solder 25 is located between the protrusions 22' and 22', and can remain on the mounting portion 26' without flowing outward from it, thus enabling stable soldering using the paste solder 25 with reduced viscosity.

[0040] Figure 8 This describes a variation of the cooling module 1” in this embodiment. In this variation, in addition to the upper edge 15b of the heat sink 15 of the heat sink 6” of the heat absorber 2”, a protrusion 36 is also formed on the aluminum component 35, and the aluminum component 35 is joined to the heat pipe 5 using paste solder 25.

[0041] Referring to the figure, 35 is, for example, an aluminum element such as a heat-receiving part that receives heat from a heat-generating component. On the flat surface 35a, where the element 35 connects with the heat pipe 5, a plurality of protrusions 36, 36 are formed protruding downwards in the direction of the heat pipe 5. Furthermore, the surface between the protrusions 36, 36 on the flat surface 35a is a mounting portion 37. The solder paste 25 is disposed at least within the space formed by the upper surface 5b of the heat pipe 5, the protrusions 36, 36, and the mounting portion 37 on the flat surface 35a, thereby creating a structure that connects with the heat pipe 5 and the element 35.

[0042] In this embodiment, the protrusion 36 is formed with a generally trapezoidal cross-section and extends along the width direction of the lower side 15c. The element 35 is mounted on the heat pipe 5 with its top 36a, located at the upper side of the trapezoid, in contact with the upper surface 5b of the heat pipe 5. The protrusion 36 has the function of retaining the paste solder 25 on the mounting portion 37 to prevent the paste solder 25 from flowing to other parts, and also functions as a solder holding mechanism.

[0043] As described above, the heat absorber 2” configured as the joint structure of the heat pipe 5 and the heat sink 6 in this embodiment includes an aluminum element 35 that is joined with the heat pipe 5. The element 35 has a plurality of protrusions 36, 36 on a flat surface 35a that is the surface joined with the heat pipe 5. The paste solder 25 is located at least in the space formed by the heat pipe 5, the flat surface 35a and the plurality of protrusions 36, 36, and is joined with the element 35 and the heat pipe 5.

[0044] With this configuration, the paste solder 25 is located between the protrusions 36, 36, and can remain on the mounting portion 37 without flowing out of it, thus enabling stable soldering using the paste solder 25 with reduced viscosity.

[0045] The present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the invention. Furthermore, the components and values ​​used in this embodiment can also be modified in various ways without departing from the spirit of the invention.

Claims

1. A heat pipe and radiator bonding structure, wherein a metal heat pipe and an aluminum radiator are bonded using a paste solder containing flux that removes oxide film, characterized in that, The radiator has multiple protrusions on the side where it connects to the heat pipe. The tops of the plurality of protrusions are all in contact with the heat pipe. The solder is located at least within the space formed by the heat pipe, the face on one side, and the plurality of protrusions, and is engaged with the heat pipe and the radiator.

2. The connection structure between the heat pipe and the radiator according to claim 1, characterized in that, The joining structure includes an aluminum component that joins with the heat sink. The heat sink has multiple protrusions for the component on the side that engages the component, i.e., the other side. The tops of the protrusions of the plurality of elements are all in contact with the element. The solder is located at least within the space formed by the element, the other side face, and the plurality of elements with protrusions, and is engaged with the element and the heat sink.

3. The connection structure between the heat pipe and the radiator according to claim 1, characterized in that, The joining structure includes an aluminum element that is connected to the heat pipe. The element has multiple heat pipe protrusions on the surface where it engages with the heat pipe. The solder is located at least within the space formed by the heat pipe, the surface that engages with the heat pipe, and the protrusions of the plurality of heat pipes, and engages with the element and the heat pipe.

4. A cooling module, characterized in that, have: The connection structure between the heat pipe and the radiator as described in any one of claims 1 to 3; and The air supply mechanism blows cooling air onto the radiator.

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