Liquid-cooling cold plate and method for manufacturing same

In a method of manufacturing a liquid-cooling cold plate, cast molding is performed after embedding a metal pipe for supplying a cooling liquid inside a casting mold. Fixing brackets to be attached to the metal pipe is provided to maintain a positional relationship between a plurality of portions of the metal pipe embedded in the casting mold. The casting molding is performed by pouring molten metal into the casting mold while the fixing metal parts are attached to the metal pipe.

FIELD OF THE INVENTION

The present invention relates to a liquid-cooling cold plate for cooling electronic components that generate intense heat, such as semiconductor devices, a CPU, an FET, a power amplifier and the like used in an electronic circuit in an electronic device, by using a liquid coolant, and a method for manufacturing the same.

BACKGROUND OF THE INVENTION

A plurality of circuit boards is tightly installed in a housing of an electronic device such as a communication device, a video device, a broadcasting device or the like. Electronic components that generate intense heat, such as semiconductor devices, a CPU (Central Processing Unit), FET (Field Effect Transistor), a power amplifier and the like, are mounted on each of the circuit boards. Accordingly, a cooling device for cooling the electronic device is required. The electronic components that generate intense heat, such as the semiconductor devices, the CPU, the power amplifier and the like, has a narrow temperature range of effective operation. Therefore, it is required to cool the electronic components individually, not the entire electronic device. As a consequence, in a recent cooling device for an electronic device, a cooling pipe through which a liquid coolant flows is provided close to each of the electronic components.

For example, in a water cooling type cold plate and a manufacturing method thereof of Patent Document 1, there is suggested a technique for improving a cooling efficiency by increasing a heat contact area between the water cooling type cold plate and a flat cooling pipe by attaching in a zigzag manner the flat cooling pipe to the water cooling type cold plate where the heating components are arranged.

In the water cooling type cold plate of Patent Document 1, a metal pipe having a circular cross sectional shape is extended in a zigzag shape. Next, at least a portion of the metal pipe which is inserted into an aluminum plate is planarized. The flat metal pipe is installed in a casting mold by a spacer and, then, molten aluminum is poured into the casting mold. Accordingly, the metal pipe having a zigzag shape is cast by the molten aluminum.

However, in the water cooling type cold plate of Patent Document 1, a bar member having a flat front surface and a flat rear surface is used as the spacer for positioning the metal pipe in the casting mold. Therefore, depending on a flowing direction of molten aluminum into the casting mold, the metal pipe is deformed by the stream pressure of the molten aluminum and misaligned with a heating component to be cooled. Accordingly, the cooling properties are not stabilized.

SUMMARY OF THE INVENTION

In view of the above, the present invention provides a liquid-cooling cold plate capable of achieving stable cooling properties by arranging a metal plate embedded in a cold plate main body in a desired position, e.g., a position directly below a heating compound while reducing misalignment and deformation of the metal pipe embedded inside the cold plate main body without being affected by the stream pressure or flowing direction of molten metal during casting, and a method for manufacturing the same.

In accordance with an aspect, there is provided a method of manufacturing a liquid-cooling cold plate, in which cast molding is performed after embedding a metal pipe for supplying a cooling liquid in a casting mold, the method including: providing fixing brackets to be attached to the metal pipe to maintain a positioning accuracy between a plurality of portions of the metal pipe embedded in the casting mold; and performing cast molding by pouring molten metal into the casting mold while attaching the fixing brackets to the metal pipe.

In the method of manufacturing a liquid-cooling cold plate, the cast molding may be performed by pouring the molten metal into the casting mold in a state where positioning is realized by fitting the fixing brackets or protrusions formed at the fixing brackets to recesses formed at the casting mold.

In the method of manufacturing a liquid-cooling cold plate, protrusions of the fixing brackets with respect to the cast-molded liquid-cooling cold plate may be planarized by milling.

In the method of manufacturing a liquid-cooling cold plate, the cast molding may be performed by pouring the metal molten into the casting mold in a state where positioning is realized by fitting protrusions formed at the casting mold to recesses formed at the fixing brackets.

In accordance with another aspect, there is provided a method of manufacturing a liquid-cooling cold plate, in which cast molding is performed after embedding a metal pipe for supplying a cooling liquid in a casting mold, the method including: providing a pipe pressing portion for pressing and fixing the metal pipe at the casting mold, and performing casting molding by pouring molten metal into the casting mold while pressing and fixing the metal pipe by the pipe pressing portion.

In the method of manufacturing a liquid-cooling cold plate, a fixing bracket to be attached to the metal pipe may be provided to maintain positional relationship between a plurality of portions of the metal pipe embedded in the casting mold; and cast molding may be performed by pouring molten metal into the casting mold while attaching the fixing brackets to the metal pipe.

In the method of manufacturing a liquid-cooling cold plate, another fixing bracket to be attached to an inlet and an outlet of the metal pipe may be provided to maintain positional relationship between the inlet and the outlet of the metal pipe which protrude from a liquid-cooling cold plate main body; and cast molding may be performed by pouring molten metal into the casting mold in a state where positioning is realized by attaching the another fixing bracket to the inlet and the outlet of the metal pipe and fitting the another fixing bracket to the casting mold.

In the method of manufacturing a liquid-cooling cold plate, at least a part of the metal pipe may be planarized.

In the method of manufacturing a liquid-cooling cold plate, a curved connection portion of the metal pipe positioned opposite to an inlet and an outlet of the metal pipe which protrude from a liquid-cooling cold plate main body may protrude from the liquid-cooling cold plate main body.

In accordance with still another aspect, there is provided a liquid-cooling cold plate including: a metal pipe configured to supply cooling liquid and a cold plate main body having the metal pipe therein, wherein a fixing bracket to be attached to the metal pipe is provided to maintain position relationship between a plurality of portions of the metal pipe embedded in the cold plate main body, and the fixing bracket is integrated with the cold plate main body by performing cast molding while the fixing bracket is attached to the metal pipe.

In the liquid-cooling cold plate, an inlet and an outlet of the metal pipe and a curved connection portion of the metal pipe positioned opposite to the inlet and the outlet of the metal pipe may protrude from the cold plate main body.

In the liquid-cooling cold plate, at least a part of the metal pipe may be planarized.

As described above, in accordance with the present invention, it is possible to arrange a metal plate embedded in a cold plate main body in a desired position, e.g., a position directly below a heating compound, and achieve stable cooling properties because misalignment and deformation of the metal pipe embedded inside the cold plate main body can be reduced without being affected by the stream pressure or flowing direction of molten metal during casting, and a method for manufacturing the same.

DETAILED DESCRIPTION OF THE EMBODIMENTS

First Embodiment

Hereinafter, a liquid-cooling cold plate according to a first embodiment will be described with reference toFIGS. 1A to 4.FIGS. 1A and 1Bare respectively a front view and a cross sectional view of the liquid-cooling cold plate according to the first embodiment.FIG. 1Ais a front view andFIG. 1Bis a cross sectional view taken along the line1B-1B inFIG. 1A.FIG. 2explains a method for attaching metal pipe fixing brackets to a metal pipe in the liquid-cooling cold plate according to the first embodiment.FIGS. 3A and 3Bare assembly diagrams showing a state in which the metal pipe fixing brackets are attached to the metal pipe in the liquid-cooling cold plate according to the first embodiment.FIG. 3Ais a front view andFIG. 3Bis a cross sectional view taken along a surface3B-3B inFIG. 3A.FIG. 4shows a state in which a casting mold is opened after molding in the case of manufacturing the liquid-cooling cold plate according to the first embodiment.

The liquid-cooling cold plate1according to the first embodiment is not limited to an electronic device such as a communication device, a video device, a broadcasting device or the like and may be applied to any electronic device having a circuit board on which electronic components that generate intense heat are mounted.

As shown inFIGS. 1A and 1B, the liquid-cooling cold plate1according to the first embodiment includes a metal pipe3, a cold plate main body2, a metal pipe fixing bracket (1)41, a metal pipe fixing bracket (2)42, and a coupler61. The liquid-cooling cold plate1supplies cooling liquid such as water or the like into the metal pipe3and takes heat from electronic components (hereinafter, referred to as “high-heat generating components”)201(n portions inFIG. 1A) that generate intense heat and are provided directly above a flat pipe straight portion3bof the metal pipe3embedded in the cold plate main body2, thereby cooling the high-heat generating components201.

Further, the high-heat generating components201shown inFIGS. 1A and 1Bare not constituent components of the liquid-cooling cold plate1but specify a positional relationship with the liquid-cooling cold plate1. The high-heat generating components201may individually be in contact with the liquid-cooling cold plate1or may collectively be in contact with the liquid-cooling cold plate1while being mounted on a circuit board (not shown). The metal pipe3positioned directly below the high-heat generating components201is a flat pipe. However, the metal pipe3may be a circular pipe or the like other than the flat pipe.

The metal pipe3is machined in a U shape by a bender and partially planarized by a presser. The metal pipe3includes a circular pipe straight portion3c, a circular pipe straight portion3a, a circular pipe curved portion3e, a flat pipe straight portion3band a circular pipe straight portion3d. The circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are embedded in the cold plate main body2. The circular pipe straight portion3c, the circular pipe straight portion3dand the circular pipe curved portion3eare provided outside the cold plate main body2. Couplers61are attached to leading ends of the circular pipe straight portion3cand3d.

Further, the metal pipe3is made of, e.g., copper, stainless steel copper or the like.

The cold plate main body2is cast-molded by inserting the metal pipe3in a casting mold to be described later and pouring molten metal such as aluminum, aluminum alloy or the like into the casting mold.

As shown inFIG. 2, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42have arc-shaped recesses41aand42aand elliptical recesses41band42b, respectively, in conformation with the shape of the metal pipe3to be disposed therebetween. In order to maintain a positional relationship between the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3embedded in the casting mold, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are attached such that the circular pipe straight portion3aand the flat pipe straight portion3bare coupled/fixed to each other at predetermined positions (m portions inFIG. 1Awhich avoid portions directly below the high-heat generating components201. The metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are made of, e.g., aluminum. The molten metal is poured into the casting mold in a state where the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are attached to the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3.

The couplers61are fluid couplers attached to leading end portions of the circular pipe straight portions3cand3dof the metal pipe3. When the liquid-cooling cold plate1is installed in the electronic device, the couplers61are fitted and connected to couplers301aof a shelf301side.

(Method for Manufacturing the Liquid-Cooling Cold Plate1)

Next, a method for manufacturing the liquid-cooling cold plate1according to the first embodiment will be described with reference toFIGS. 2 to 4.

Before the metal pipe3is embedded in a casting mold, first, as shown inFIGS. 2 and 3, the predetermined portions (m portions inFIG. 1Awhich avoid portions directly below the high-heat generating components201) of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are sandwiched between the recesses41aand42aof the metal pipe fixing bracket (1)41and the recesses41band42bof the metal pipe fixing bracket (2)42, respectively. Then, fixing pins43are inserted into through-holes41cof the metal pipe fixing bracket (1)41and through-holes42of the metal pipe fixing bracket (2)42, thereby pressing and fixing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42. As can be seen fromFIG. 4to be described later, surfaces of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42which are opposite to the surfaces where the recesses are formed are designed to protrude compared to the surface of the cold plate main body2. By sandwiching and pressing the protrusions by the casting mold, the misalignment of the metal pipe3is reduced.

As shown inFIG. 4, the casting mold (1)101and the casting mold (2)102are closed in a state where the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42attached to the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are fitted to a recessed groove101aof the casting mold (1)101and a recessed groove102aof the casting mold (2)102. By pouring molten metal in the casting mold (1)101and the casting mold (2)102which are closed, the liquid-cooling cold plate1shown inFIGS. 1A and 1Bis cast-molded.

In other words, by sandwiching and firmly pressing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42by the recessed groove101aof the casting mold (1)101and the recessed groove102aof the casting mold (2)102, the misalignment and the deformation of the metal pipe3by the stream pressure of the molten metal during the casting can be reduced. Accordingly, the misalignment and the deformation of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3can be reduced.

In the above embodiment, the recessed grooves are formed at the casting mold by using a metal casting mold. However, in the case of using a sand mold as the casting mold, for example, the recessed grooves can be formed at the casting mold while closing the mold by setting a dimension of the metal pipe fixing bracket to be greater than an inner dimension of the casting mold after the mold is closed.

As shown inFIG. 4, after the cast molding, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42protrude compared to the surface of the cold plate main body2. Therefore, the smoothness of the surface of the liquid-cooling cold plate1is ensured by milling the entire surface of the liquid-cooling cold plate1or only protruded portions of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42.

In the above embodiment, the positioning between the casting mold and the metal pipe fixing bracket is performed by fitting the protruded portions of the metal pipe fixing brackets to the recessed grooves of the casting mold. On the contrary, it is also possible to perform the positioning between the casting mold and the metal pipe fixing brackets by providing positioning pins on a surface, to be in contact with the metal pipe fixing brackets, of the casting mold and forming recessed holes to be fitted to the positioning pins at positions corresponding to the positions of the positioning pins of the metal pipe fixing brackets.

Further, in the above embodiment, the recessed grooves are formed at the casting mold by using a metal casting mold. However, in the case of using a sand mold as the casting mold, for example, the recessed grooves can be formed at the casting mold while closing the mold by setting a dimension of the positioning pins to be greater than an inner dimension of the casting mold after the mold is closed, considering a deformation error of the casting mold.

As described above, in accordance with the liquid-cooling cold plate1according to the first embodiment, the misalignment and the deformation of the metal pipe embedded in the cold plate main body can be reduced without being affected by the stream pressure and the flowing direction of the molten metal during the casting. Therefore, the metal pipe can be provided at a desired position, e.g., a position directly below the heat-generating component or the like, and stable cooling properties can be obtained.

Second Embodiment

Hereinafter, a liquid-cooling cold plate according to a second embodiment will be described with reference toFIGS. 5A to 7.FIGS. 5A and 5Bare respectively a front view of a cross sectional view of the liquid-cooling cold plate according to the second embodiment.FIG. 5Ais a front view andFIG. 5Bis a cross sectional view taken along the line5B-5B shown inFIG. 5A.FIG. 6shows a state in which the casting mold is opened after molding in the case of manufacturing the liquid-cooling cold plate according to the second embodiment.FIG. 7shows another example of the state in which the casting mold is opened after molding in the case of manufacturing the liquid-cooling cold plate according to the second embodiment. InFIGS. 5A to 7, like reference numerals will be used for like parts, and redundant description thereof will be omitted.

The liquid-cooling cold plate11according to the second embodiment may be applied to any electronic device having a circuit board on which electronic components that generate intense heat without being limited to an electronic device such as a communication device, a video device, a broadcasting device or the like.

(Configuration of the Liquid-Cooling Cold Plate11)

As shown inFIGS. 5A and 5B, the liquid-cooling cold plate11according to the second embodiment includes a metal pipe4, a cold plate main body12and a coupler61. The liquid-cooling cold plate11supplies cooling liquid such as water or the like into the metal pipe4and takes heat from electronic components (hereinafter, referred to as “high-heat generating components”)201(n portions inFIG. 5A) that generate intense heat and are provided directly above a circular pipe straight portion4bof the metal pipe4embedded in the cold plate main body12, thereby cooling the high-heat generating components201.

Further, the high-heat generating components201shown inFIGS. 5A and 5Bare not constituent components of the liquid-cooling cold plate11but specify a positional relationship with the liquid-cooling cold plate11. The high-heat generating components201may individual be in contact with the liquid-cooling cold plate11or may collectively be in contact with the liquid-cooling cold plate11while being mounted on a circuit board (not shown). The metal pipe4positioned directly below the high-heat generating components201is a circular pipe. However, the metal pipe4may be a flat pipe or the like other than the circular pipe.

The metal pipe4is machined in a U shape by a bender. The metal pipe4includes circular pipe straight portions4cand4a, a circular pipe curved portion4e, circular pipe straight portions4band4d. The circular pipe straight portion4aand the circular pipe straight portion4bof the metal pipe4are embedded in the cold plate main body12. The circular pipe straight portion4c, the circular pipe straight portion4dand the circular pipe curved portion4eare provided outside the cold plate main body12. Couplers61are attached to leading ends of the circular pipe straight portion4cand4d.

Further, the metal pipe4is made of, e.g., copper, stainless steel copper or the like.

The cold plate main body12is cast-molded by pouring molten metal such as aluminum, aluminum alloy or the like into a casting mold to be described later. As shown inFIGS. 5A and 5B, a pair of recesses (1) and (2)12aand12bwith the metal pipe4interposed therebetween is formed at a plurality of predetermined portions (p portions inFIG. 5Awhich avoid portions directly below the high-heat generating components201). The recesses (1)12aand (2)12bare formed by a protrusion111aof the casting mold (1)111and a protrusion112aof the casting mold (2)112which will be described later.

The couplers61are fluid couplers attached to leading end portions of the circular pipe straight portions4cand4dof the metal pipe4. When the liquid-cooling cold plate1is installed in the electronic device, the couplers61are fitted and connected to couplers301aof the shelf301side which will be described later.

(Method for Manufacturing the Liquid-Cooling Cold Plate11)

Hereinafter, a method for manufacturing the liquid-cooling cold plate11according to the second embodiment will be described with reference toFIG. 6.

As shown inFIG. 6, the casting mold (1)111and the casting mold (2)112have the protrusions111aand112aformed in conformation with the shape of the metal pipe4, respectively, at predetermined positions thereof (p positions indicated inFIG. 5Awhich correspond to the positions of the recesses (1) and (2)12aand12bof the cold plate main body12). When the casting mold (1)111and the casting mold (2)112are closed, the circular pipe straight portions4aand4bof the metal pipe4are sandwiched at the same time by the protrusion111aof the casting mold (1)111and the protrusion112aof the casting mold (2)112, thereby positioning the circular pipe straight portions4aand4bof the metal pipe4. By pouring molten metal into the casting mold (1)111and the casting mold (2)112which are closed, the liquid-cooling cold plate11shown inFIGS. 5A and 5Bis cast-molded.

In other words, by sandwiching and firmly pressing the circular pipe straight portions4aand4bof the metal pipe4from opposite sides by the protrusion111aof the casting mold (1)111and the protrusion112aof the casting mold (2)112, the misalignment and the deformation of the metal pipe4by the stream pressure of the molten metal during the casting can be reduced. Accordingly, it is possible to reduce the misalignment and the deformation of the circular pipe straight portions4aand4bof the metal pipe4.

Next, a method for manufacturing the metal pipe3having the flat pipe straight portion3bwhich constitutes the liquid-cooling cold plate1according to the first embodiment will be described.

As shown inFIG. 7, the casting mold (1)121and the casting mold (2)122have protrusions121aand122aformed in conformation with the shape of the circular pipe straight portion3aof the metal pipe3and protrusions121band122bformed in conformation with the shape of the flat pipe straight portion3bof the metal pipe3, respectively, at predetermined positions thereof (p positions indicated inFIG. 5Awhich correspond to the positions of the recesses (1) and (2)12aand12bof the cold plate main body12). When the casting mold (1)121and the casting mold (2)122are closed, the circular pipe straight portion3aof the metal pipe3is sandwiched between the protrusion121aof the casting mold (1)121and the protrusion122aof the casting mold (2)122, and the flat pipe straight portion3bof the metal pipe3is sandwiched between the protrusion121bof the casting mold (1)121and the protrusion122bof the casting mold (2)122, thereby positioning the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3. By pouring the molten metal into the casting mold (1)121and the casting mold (2)122which are closed, the liquid-cooling cold plate11shown inFIGS. 5A and 5Bis cast-molded.

In other word, by sandwiching and firmly pressing the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3from opposite sides by the protrusions121aand121bof the casting mold (1)121and the protrusions122aand122bof the casting mold (2)122, the deformation of the metal pipe3by the stream pressure of the molten metal during the casting can be reduced. Accordingly, it is possible to reduce the misalignment of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3.

As described above, in accordance with the liquid-cooling cold plate11according to the second embodiment, the misalignment and the deformation of the metal pipe embedded into the cold plate main body can be reduced without being affected by the stream pressure and the flowing direction of the molten metal during the casting. Therefore, the metal pipe embedded in the cold plate main body can be provided at a desired position, e.g., a position directly below the heating component or the like. Accordingly, stable cooling properties can be obtained.

Third Embodiment

Hereinafter, a liquid-cooling cold plate according to a third embodiment will be described with reference toFIGS. 8A to 9B.FIGS. 8A to 8Care respectively a front view and cross sectional views of the liquid-cooling cold plate according to the third embodiment.FIG. 8Ais a front view andFIGS. 8B and 8Care a cross sectional view taken along a surface8B-8B shown inFIG. 8Aand a cross sectional view taken along an8C-8C surface shown inFIG. 8A, respectively.FIGS. 9A and 9Bshow a state in which the casting mold is opened after the casting in the case of manufacturing the liquid-cooling cold plate according to the third embodiment. InFIGS. 8A to 9B, like reference numerals will be used for like parts, and redundant description thereof will be omitted.

A liquid-cooling cold plate81according to the third embodiment is characterized in that the techniques of the liquid-cooling cold plates according to the first and the second embodiment are combined.

In the first embodiment, the metal pipe fixing brackets are used to reduce the misalignment and the deformation of the metal pipe embedded in the cold plate main body. In order to further reduce the misalignment and the deformation of the metal pipe, it is required to increase the number of the metal pipe fixing brackets and decrease the interval (pitch) of attachment of the metal pipe fixing brackets to the metal pipe. However, when the number of the metal pipe fixing brackets is increased, the flow of molten metal during the casting is disturbed or the cost is increased.

In the second embodiment, the metal pipe is pressed from opposite sides by the protrusions formed at the casting mold in order to reduce the misalignment and the deformation of the metal pipe embedded in the cold plate main body. In order to further reduce the misalignment and the deformation of the metal pipe, it is required to increase portions for pressing the metal pipe by increasing the number of the protrusions formed at the casting mold. In other words, it is required to decrease the interval (pitch) of the protrusions formed at the casting mold. However, when the number of the portions for pressing the metal pipe is increased, the number of recesses formed at the cold plate main body is also increased. Accordingly, the cooling properties of the cold plate deteriorate.

Therefore, in the third embodiment, the techniques of the first and the second embodiment are employed to decrease the number of the metal pipe fixing brackets and press portions of the metal pipe between the adjacent metal pipe fixing brackets by the protrusions formed at the casting mold. Accordingly, the misalignment and the deformation of the metal pipe can be further reduced without being affected by the stream pressure and the flowing direction of the molten metal during the casting. Further, the cooling properties can be further improved in a cost effective manner.

The liquid-cooling cold plate81according to the third embodiment is not limited to an electronic device such as a communication device, a video device, a broadcasting device or the like and may be applied to any electronic device having a circuit board on which electronic components that generate intense heat are mounted.

(Configuration of the Liquid-Cooling Cold Plate81)

As shown inFIGS. 8A to 8C, the liquid-cooling cold plate81according to the third embodiment includes a metal pipe3, a cold plate main body82, a metal pipe fixing bracket (1)41, a metal pipe fixing bracket (2)42, and couplers61. The liquid-cooling cold plate81supplies cooling liquid such as water or the like into the metal pipe3and takes heat from electronic components (hereinafter, referred to as “high-heat generating components”)201(n portions inFIG. 8A) that generate intense heat and are provided directly above a flat pipe straight portion3bof the metal pipe3embedded in the cold plate main body82, thereby cooling the high-heat generating components201.

Further, the high-heat generating components201shown inFIGS. 8A to 8Care not constituent components of the liquid-cooling cold plate81but specify a positional relationship with the liquid-cooling cold plate81. The high-heat generating components201may individually be in contact with the liquid-cooling cold plate81or may collectively be in contact with the liquid-cooling cold plate81while being mounted on a circuit board (not shown). The metal pipe3positioned directly below the high-heat generating components201is a flat pipe. However, the metal pipe4may be a circular pipe or the like other than the flat pipe.

The cold plate main body82is cast-molded by pouring molten metal such as aluminum, aluminum alloy or the like into a casting mold to be described later. As shown inFIG. 8C, the cold plate main body82has a pair of recesses (1) and (2)82aand82bwith the metal pipe3interposed therebetween and a pair of recesses (3) and (4)82cand82dwith the metal pipe3interposed therebetween at predetermined positions thereof (r portions and s portions inFIG. 8Awhich avoid portions directly below the high-heat generating components201). The recess (1)82a, the recess (2)82b, the recess (3)82cand the recess (4)82dare formed by the protrusion131bof the casting mold (1)131, the protrusion132bof the casting mold (2)132, the protrusion131cof the casting mold (1)131, and the protrusion132cof the casting mold (2)132, respectively, which will be described later.

As in the case shown inFIGS. 3A and 3B, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are attached such that the circular pipe straight portion3aand the flat pipe straight portion3bare coupled and fixed at the predetermined positions (m portions inFIG. 8Awhich avoid portions directly below the high-heat generating components201). The metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are made of, e.g., aluminum. The molten metal is poured into the casting mold in a state where the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42are attached to the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3.

(Method for Manufacturing the Liquid-Cooling Cold Plate81)

Next, a method for manufacturing the liquid-cooling cold plate81according to the third embodiment will be described with reference toFIGS. 9A and 9B.

Before the metal pipe3is embedded in a casting mold, first, as shown inFIGS. 2 and 3, the predetermined portions (m portions inFIG. 8Awhich avoid portions directly below the high-heat generating components201) of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are sandwiched between the recesses41aand42aof the metal pipe fixing bracket (1)41and the recesses41band42bof the metal pipe fixing bracket (2)42, respectively. Then, fixing pins43are inserted into through-holes41cof the metal pipe fixing bracket (1)41and through-holes42of the metal pipe fixing bracket (2)42, thereby pressing and fixing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42. As can be seen fromFIG. 4described above, surfaces of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42which are opposite to the surfaces where the recesses are formed are designed to protrude compared to the surface of the cold plate main body2. By pressing the protrusions with the casting mold, the misalignment of the metal pipe3is reduced.

As shown inFIG. 9A, the casting mold (1)131and the casting mold (2)132are closed in a state where the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42attached to the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are fitted to the recessed groove131aof the casting mold (1)131and the recessed groove132aof the casting mold (2)132.

In the above embodiment, the recessed grooves are formed at the casting mold by using the metal casting mold. However, in the case of using a sand mold as the casting mold, for example, the recessed grooves can be formed at the casting mold while closing the mold by setting a dimension of the metal pipe fixing bracket to be greater than an inner dimension of the casting mold after closing the mold.

Similarly, as shown inFIG. 9B, the casting mold (1)131and the casting mold (2)132have the protrusions131band132bformed in conformation with the shape of the circular pipe straight portion3aof the metal pipe3and the protrusions131cand132cformed in conformation with the shape of the flat pipe straight portion3bof the metal pipe3, respectively, at predetermined positions thereof (r portions and s portions inFIG. 8Awhich correspond to the positions of the recess (1)82a, the recess (2)82b, the recess (3)82cand the recess (4)82dof the cold plate main body82). When the casting mold (1)131and the casting mold (2)132are closed, the circular pipe straight portion4aof the metal pipe3and the flat pipe straight portion3bof the metal pipe3are sandwiched at the same time by the protrusion131bof the casting mold (1)131and the protrusion132bof the casting mold (2)132and by the protrusions131cof the casting mold (1)131and the protrusion132cof the casting mold (2)132, respectively. Accordingly, the positioning between the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3is performed.

By pouring molten metal into the casting mold (1)131and the casting mold (2)132which are closed, the liquid-cooling cold plate81shown inFIGS. 8A to 8Cis cast-molded.

In other words, by sandwiching and firmly pressing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42by the recessed groove131aof the casting mold (1)131and the recessed groove131aof the casting mold (2)132and by sandwiching and firmly pressing the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3by the protrusions131band131cof the casting mold (1)131and the protrusions132band132cof the casting mold (2)132, the misalignment and the deformation of the metal pipe3by the stream pressure of the molten metal during the casting can be reduced. Accordingly, it is possible to reduce the misalignment and the deformation of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3.

As shown inFIG. 9A, after molding of the casting mold, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42protrude compared to the surface of the cold plate main body82. Therefore, the smoothness of the surface of the liquid-cooling cold plate81is ensured by milling the entire surface of the liquid-cooling cold plate81or only protruded portions of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42.

In the above embodiment, the positioning between the casting mold and the metal pipe fixing bracket is performed by fitting the protruded portions of the metal pipe fixing brackets into the recessed grooves of the casting mold. On the contrary, it is also possible to perform the positioning between the casting mold and the metal pipe fixing brackets by providing positioning pins on a surface, to be in contact with the metal pipe fixing brackets, of the casting mold and forming recessed holes, to be fitted to the positioning pins, at positions of the metal pipe fixing brackets corresponding to the positions of the positioning pins.

Further, in the above embodiment, the recessed grooves are formed at the casting mold by using a metal casting mold. However, in the case of using a sand mold as the casting mold, for example, the recessed grooves can be formed at the casting mold while closing the mold by setting a dimension of the positioning pins to be greater than an inner dimension of the casting mold after closing the mold, considering a deformation error of the casting mold.

As described above, in accordance with the liquid-cooling cold plate81according to the third embodiment, the misalignment and the deformation of the metal pipe embedded in the cold plate main body can be reduced without being affected by the stream pressure and the flowing direction of the molten metal during the molding. Therefore, the metal pipe embedded in the cold plate main body can be provided at a desired position, e.g., a position directly below the heating component or the like, and stable cooling properties can be obtained.

The cooling properties can be further improved in a cost effective manner by decreasing the number of the metal pipe fixing brackets and pressing portions of the metal pipe between the adjacent metal pipe fixing brackets by the protrusions formed at the casting mold.

Fourth Embodiment

Hereinafter, a liquid-cooling cold plate according to a fourth embodiment will be described with reference toFIGS. 10A to 12.FIGS. 10A and 10Bexplain a method for attaching a metal pipe fixing bracket and a coupler fixing bracket to a metal pipe in the liquid-cooling cold plate according to the fourth embodiment.FIG. 10Ais a front view andFIG. 10Bshows the coupler fixing bracket in detail.FIG. 11is an assembled diagram showing a state in which the metal pipe fixing bracket and the coupler fixing bracket are attached to the metal pipe in the liquid-cooling cold plate according to the fourth embodiment.FIG. 12explains an operation of fitting couplers of the liquid-cooling cold plate to couplers of the shelf side in the liquid-cooling cold plate according to the fourth embodiment. Like reference numerals inFIGS. 10 to 12designate like parts inFIGS. 1A to 9B, and redundant description thereof will be omitted.

The liquid-cooling cold plate31according to the fourth embodiment is not limited to an electronic device such as a communication device, a video device, a broadcasting device or the like and may be applied to any electronic device having a circuit board on which electronic components that generate intense heat are mounted.

(Configuration of the Liquid-Cooling Cold Plate31)

The configuration of the liquid-cooling cold plate31according to the fourth embodiment is the same as that of the liquid-cooling cold plate1according to the first embodiment except for a method of positioning the metal pipe3in manufacturing the liquid-cooling cold plate31. In other words, in the liquid-cooling cold plate31according to the fourth embodiment, the positioning accuracy of the two couplers61of the liquid-cooling cold plate31is further improved because when the liquid-cooling cold plate31is mounted in the electronic device, the two couplers61serving as an inlet and an outlet of cooling liquid supplied to the liquid-cooling cold plate31need to be slide-fitted to the two couplers301aof the shelf301side at the same time, as can be seen fromFIG. 12.

(Method for Manufacturing the Liquid-Cooling Cold Plate31)

Next, a method for manufacturing the liquid-cooling cold plate31according to the fourth embodiment will be described with reference toFIGS. 10A, 10B and 11.

As in the case of the liquid-cooling cold plate1according to the first embodiment, before the metal pipe3is embedded in a casting mold, first, as shown inFIGS. 2 and 3, the predetermined portions (m portions inFIG. 1Awhich avoid portions directly below the high-heat generating components201) of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are sandwiched between the recesses41aand42aof the metal pipe fixing bracket (1)41and the recesses41band42bof the metal pipe fixing bracket (2)42, respectively. Then, the fixing pins43are inserted into the through-holes41cof the metal pipe fixing bracket (1)41and the through-holes42of the metal pipe fixing bracket (2)42, thereby pressing and fixing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42. As can be seen fromFIG. 4, the surfaces of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42which are opposite to the surfaces where the recesses are formed are designed to protrude compared to the surface of the cold plate main body2. By pressing the protrusions with the casting mold, the misalignment of the metal pipe3is reduced.

As shown inFIGS. 10A and 10B, by fitting two circular holes51aformed at the coupler fixing bracket51to the leading ends of the two couplers61attached to the metal pipe3, the couplers61are fixed by the coupler fixing bracket51and positioned at a predetermined interval.

The coupler fixing unit51is made of, e.g., stainless steel or the like.

As shown inFIG. 4, the casting mold (1)101and the casting mold (2)102are closed in a state where the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42attached to the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3are fitted to the recessed groove101aof the casting mold (1)101and the recessed groove102aof the casting mold (2)102and also in a state where the coupler fixing bracket51is fitted to a predetermined position in the casting mold (1)101and the casting mold (2)102. By pouring molten metal into the casting mold (1)101and the casting mold (2)102which are closed, the liquid-cooling cold plate31having the same shape as that shown inFIGS. 1A and 1Bis cast-molded.

In other words, by sandwiching and firmly pressing the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42from opposite sides by the recessed groove101aof the casting mold (1)101and the recessed groove102aof the casting mold (2)102, the deformation of the metal pipe3by the stream pressure of the molten metal during the casting can be reduced. Accordingly, it is possible to reduce the misalignment of the circular pipe straight portion3aand the flat pipe straight portion3bof the metal pipe3.

Since the cast molding is performed in a state where the coupler fixing bracket51is fitted to the predetermined position in the casting mold (1)101and the casting mold (2)102, the misalignment of the two couplers61can be reduced.

Therefore, when the liquid-cooling cold plate31is slide-connected to the shelf301, the coupler61of the liquid-cooling cold plate31and the coupler301aof the shelf301side can be easily connected.

The coupler fixing bracket51may be separated from the coupler61after the molding to be used again.

As shown inFIG. 4, after the cast molding, the metal pipe fixing bracket (1)41and the metal pipe fixing bracket2(42) are protruded compared to the surface of the cold plate main body2. Therefore, the smoothness of the surface of the liquid-cooling cold plate1is ensured by milling the entire surface of the liquid-cooling cold plate1or only protruded portions of the metal pipe fixing bracket (1)41and the metal pipe fixing bracket (2)42.

As described above, in accordance with the liquid-cooling cold plate31according to the fourth embodiment, the misalignment and the deformation of the metal pipe embedded in to cold plate main body can be reduced without being affected by the stream pressure and the flowing direction of the molten metal during the casting. Therefore, the metal pipe can be provided at a desired position, e.g., a position directly below the heating component or the like, and stable cooling properties can be obtained.

Further, the working efficiency in connecting the couplers of the liquid-cooling cold plate and the couplers of the shelf side can be improved.

The present invention is not limited to the above embodiments and may be variously modified without departing from the scope of the invention. Further, various modifications may be made by appropriately combining a plurality of constituent elements that are not disclosed in the above embodiments.

INDUSTRIAL APPLICABILITY

The present invention is not limited to an electronic device such as a communication device, a video device and a broadcasting device and may be used in an industry of manufacturing an electronic device having a circuit board on which electronic components that generate intense heat are mounted.