Patent Publication Number: US-9897393-B2

Title: Heat dissipating module

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a heat dissipating module and in particular to a heat dissipating module which is used for heat dissipation. 
     Description of Prior Art 
     As the current electronic equipment gradually having compact and lightweight design to meet customers&#39; requirements, the sizes of the electronic components thereof decrease accordingly. When the electronic equipment shrinks, the accompanying heat creates the major barrier to the performance of electronic equipment and system improvement. Therefore, to effectively deal with the problem of heat dissipation of the components in the electronic equipment, the industry proposes the vapor chamber and heat pipe which have better performance of heat transfer to solve the present issue of heat dissipation. 
     The vapor chamber is a shell body (or planar body) having a rectangular shape. There are wick structures disposed on the chamber wall in the shell body and there is working liquid filled in the shell body. One side (i.e., evaporation region) of the shell body is attached to a heat generating device such as a CPU, a Northbridge, a Southbridge, a transistor, and a MCU to absorb the heat generated by the heat generating device such that the working liquid in the liquid state is vaporized in the evaporation region of the shell body to transform into the vapor state. In this way, the heat is transferred to the condensation region of the shell body. Then, the working liquid in the vapor state is cooled and condensed in the condensation region to transform into the working liquid in the liquid state which flows back to the evaporation region by gravity or wick structures to continue the liquid-vapor circulation. Thus, an effective effect of uniform-temperature heat dissipation is achieved. 
     The operating principle and theoretical structure of the heat pipe are the same as those of the vapor chamber. As for the vapor chamber, the hollow portion of its circular pipe is filled with metal powder (or woven mesh) to form a circular wick structure on the inner wall of the heat pipe by a sinter process. Then, the heat pipe is pumped down into a vacuum state and filled with a working liquid. Finally, the heat pipe is sealed to form a heat pipe structure. When the working liquid is heated in the evaporation region to vaporize, it diffuses to the condensation end. The working liquid in the evaporation region is in a vapor state. After it leaves the evaporation region and diffuses into the condensation end, it is gradually cooled and transformed into a liquid state. Then, the working liquid flows back to the evaporation region through the wick structure. 
     The difference between the vapor chamber and the heat pipe is the heat transfer type. The heat transfer type of the vapor chamber is two-dimensional and planar, while the heat transfer of the heat pipe is one-dimensional. 
     How to use these two types of heat transfer units more effectively is the target which the industry currently strives to reach. 
     SUMMARY OF THE INVENTION 
     Thus, to effectively overcome the above problems, one objective of the present invention is to provide a first flat shell body which is connected to a plurality of second flat shell bodies individually through a plurality of heat pipes such that the working fluids in the second flat shell bodies flow into the first flat shell body for heat dissipation. 
     Another objective of the present invention is to provide a first flat shell body disposed above the second flat shell bodies each of which is connected to and below the first flat shell body through a heat pipe such that the working fluids in the second flat shell bodies are heated to vaporize and flow into the first flat shell body to dissipate heat and then flow back to the second flat shell bodies from the first flat shell body by gravity and the wick structures. 
     Still another objective of the present invention is to provide a heat pipe having two open ends which are individually pressed against the inner side of the first chamber of the first flat shell body and the inner side of the second chamber of the second flat shell body such that a heat pipe wick structure of the heat pipe is connected to the first wick structure and the second wick structure through the open ends by a capillary connection. 
     Yet another objective of the present invention is to provide a heat pipe having two open ends extending to press against the inner sides of the two chambers of the first and second flat shell bodies. Two throughholes are individually disposed at two extension portions extending from the heat pipe into the two chambers such that the heat pipe channel of the heat pipe communicates with the two chambers. 
     Still yet another objective of the present invention is to provide a first flat shell body with a large heat dissipating area, which is connected to a plurality of second flat shell bodies with small heat absorbing areas through a plurality of heat pipes such that the working fluids in the second flat shell bodies can flow to the large dissipating area of the first flat shell body through the heat pipes to dissipate heat. 
     Another objective of the present invention is to provide a heat pipe whose pipe wall having an inner surface provided with a plurality of ribs disposed spacedly. A groove is disposed between each two adjacent ribs. The heat pipe wick structure is formed on the ribs and the grooves. Thus, the area of the heat pipe wick structure increases and the efficiency of the capillary channel of the heat pipe channel is enhanced. 
     Another objective of the present invention is to provide a heat pipe channel of a heat pipe. A supporting cylinder is disposed in the heat pipe channel and a cylindrical wick structure is disposed on the outer surface of the supporting cylinder. Thus, the supporting force between the first flat shell body and the second flat shell bodies can be enhanced through the heat pipes and the supporting cylinders. Also, the reflow capillary paths between the first chamber and the second chambers can be improved through the heat pipe wick structure and the cylindrical wick structure. 
     To achieve the above objectives, the present invention provides a heat dissipating module which comprises a first flat shell body and a plurality of second flat shell bodies. The first flat shell body defines a first chamber and has a plurality of first holes communicating with the first chamber; the first chamber has a first wick structure. Each of the second flat shell bodies defines a second chamber and has at least one second hole communicating with the second chamber; the second flat shell body is provided with a working fluid and a second wick structure therein. Each of the second flat shell bodies is connected to the first flat shell body through a heat pipe having a heat pipe channel and a heat pipe wick structure. The heat pipe channel is connected to the second chamber and the first chamber. The heat pipe wick structure is disposed in the heat pipe channel and connected to the first wick structure and the second wick structure by a capillary connection. 
     In one embodiment, the first flat shell body has a first outer top surface defining a heat dissipating area; each of the second flat shell bodies has a second outer bottom surface defining a heat absorbing area; the heat dissipating area of the first flat shell body is larger than the heat absorbing area of each of the second flat shell bodies. 
     In one embodiment, the first flat shell body has a first outer top surface defining a heat dissipating area; each of the second flat shell bodies has a second outer bottom surface defining a heat absorbing area; the heat dissipating area of the first flat shell body is larger than the sum of the absorbing areas of the second flat shell bodies. 
     In one embodiment, the first flat shell body is disposed above the second flat shell bodies. 
     In one embodiment, the second flat shell bodies are disposed to a left-and-right arrangement below the first flat shell body. 
     In one embodiment, the heat pipe has a pipe wall, a first extension portion, and a second extension portion opposite to the first extension portion. The first extension portion forms a first open end and the second extension portion forms a second open end. The heat pipe channel and the heat pipe wick structure are both disposed in the pipe wall and between the first open end and the second open end. 
     In one embodiment, the first extension portion extends from the first open end into the first chamber such that the first open end is pressed against the first wick structure on the top side in the first chamber; the second extension portion extends from the second open end into the second chamber such that the second open end is pressed against the second wick structure on the bottom side in the second chamber. 
     In one embodiment, the heat pipe wick structure is connected to the first wick structure and the second wick structure through the first open end and the second open end in a capillary way. 
     In one embodiment, the first extension portion and the second extension portion are provided with a first throughhole and a second throughhole, respectively, both penetrating through the pipe wall. The heat pipe channel communicates with the first chamber and the second chamber through the first throughhole and the second throughhole, respectively. 
     In one embodiment, the pipe wall has an inner surface facing the heat pipe channel and the inner surface is provided with a plurality of ribs disposed spacedly. A groove is disposed between each two adjacent ribs. The grooves and the ribs are interlaced with one another and extend along a longitudinal direction of the heat pipe. 
     In one embodiment, a supporting cylinder is disposed in the heat pipe channel and extends along a longitudinal direction of the heat pipe. Two opposite ends of the supporting cylinder are individually pressed against the first wick structure on the top side in the first chamber and the second wick structure on the bottom side in the second chamber. 
     In one embodiment, the supporting cylinder is made of metal and is provided with a cylindrical wick structure on an outer surface thereof. 
     In one embodiment, the supporting cylinder is made of metal sintered powder. 
     In one embodiment, the first flat shell body and the second flat shell bodies are vapor chambers or planar uniform-temperature heat pipes. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
       The purpose of the following drawings is to make the present invention understood easily. The descriptions of the drawings will be detailed in the specification and incorporated to be part of the embodiments. Through the embodiments in the specification and reference to the corresponding figures, the embodiments of the present invention will be explained in detail and the operating theory will be described. 
         FIG. 1A  is a perspective exploded view of the present invention; 
         FIG. 1B  is a perspective exploded view of the present invention from another view; 
         FIG. 2  is a perspective assembled view of the present invention; 
         FIG. 3A  is a partial top view of the present invention; 
         FIG. 3B  is a partial cross-sectional view of the present invention; 
         FIG. 4A  is a partial top view of the heat pipe according to an alternative embodiment of the heat pipe of the present invention; 
         FIG. 4B  is a partial cross-sectional view of the heat pipe according to an alternative embodiment of the heat pipe of the present invention; 
         FIG. 5A  is a partial top view of the heat pipe according to another alternative embodiment of the heat pipe of the present invention; 
         FIG. 5B  is a partial cross-sectional view of the heat pipe according to another alternative embodiment of the heat pipe of the present invention; 
         FIG. 6A  is a cross-sectional view of the heat dissipating module according to the first embodiment of the present invention; and 
         FIG. 6B  is a cross-sectional view of the heat dissipating module according to another condition of the first embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The above objectives, structural and functional characteristics of the present invention will be described according to the preferred embodiments in the accompanying drawings. 
     The present invention provides a heat dissipating module which comprises a first flat shell body and a plurality of second flat shell bodies. The first flat shell body has first chamber having a first wick structure formed on an inner wall of the first chamber. Each of the second flat shell bodies defines a second chamber. The second chamber has a working fluid and a second wick structure therein. Each of the second flat shell bodies is connected to and below the first flat shell body through a heat pipe. Each second chamber communicates with the first chamber through the corresponding heat pipe. The working fluid in each of the second chambers flows into the first chamber through the corresponding heat pipe to dissipate heat and then flows back to the second chamber through the corresponding heat pipe. 
     The embodiments of the present invention will be detailed below in reference to the accompanying drawings, the reference signs, and the explanation thereof. 
       FIG. 1A  is a perspective exploded view of the present invention. 
       FIG. 1B  is a perspective exploded view of the present invention from another view.  FIG. 2  is a perspective assembled view of the present invention.  FIG. 3A  is a partial top view of the present invention.  FIG. 3B  is a partial cross-sectional view of the present invention. As shown in the above figures, a heat dissipating module comprises a first flat shell body  11  and a plurality of second flat shell bodies  12 . The first flat shell body  11  is disposed above the second flat shell bodies  12 . In the current embodiment, there are two second flat shell bodies  12  disposed to a left-and-right arrangement below the first flat shell body  11 . The first flat shell body  11  and the second flat shell bodies  12  are preferably made of metal with high heat conductivity such as gold, silver, copper, or the alloy thereof. The first flat shell body  11  and the second flat shell bodies  12  are physically embodied as vapor chambers or planar uniform-temperature heat pipes. 
     The interior of the first flat shell body  11  defines a first chamber  111 . The first flat shell body  11  has a first outer bottom surface  112 , a first outer top surface  113 , and a plurality of first holes  114  penetrating through the bottom surface  112  and communicating with the first chamber  111 . A first wick structure  115  is disposed on an inner wall of the first chamber  111 . The first chamber  111  has a top side  1111  spaced with the first holes  114  correspondingly. The first outer top surface  113  is used for heat dissipation and defines a heat dissipating area. The heat dissipating area is the surface area of the first outer top surface  113 . For example, the first outer top surface  113  shown in  FIG. 1A  is a rectangle and its surface area equals the product of the length and the width of the first outer top surface  113 . In another embodiment, if the first outer top surface  113  is a circle, its surface area equals the product of 3.14 and the radius squared. 
     The interior of each of the second flat shell bodies  12  defines a second chamber  121 . The second flat shell body  12  has a second outer bottom surface  122  facing the first outer bottom surface  112  of the first flat shell body  11  and a second outer top surface  123  provided with at least one second hole  124  communicating with the second chamber  121 . The second chamber  121  is provided with a working fluid  125  and a second wick structure  126  therein. The second wick structure  126  is disposed on the inner wall of the second chamber  121 . The second chamber  121  has a bottom side  1211  spaced with the second hole  124  correspondingly. Each of the second flat shell bodies  12  is connected to the first flat shell body  11  through a heat pipe  13  such that the second chambers  121  individually communicate with the first chamber  111  of the first flat shell body  11  through the corresponding heat pipes  13 . The second outer bottom surface  122  in  FIGS. 1A and 1B  is a surface protruding downward and used for heat absorption and defines a heat absorbing area. The heat absorbing area is the surface area of the second outer bottom surface  122 . For example, the second outer bottom surface  122  shown in  FIG. 1B  is a rectangle and its surface area equals the product of the length and the width of the second outer bottom surface  122 . In another embodiment, if the shape of the second outer bottom surface  122  is a circle, then its surface area equals the product of 3.14 and the radius squared. 
     In a preferred embodiment, the heat dissipating area of the first flat shell body  11  is larger than the heat absorbing area of each of the second flat shell bodies  12 . In another preferred embodiment, the heat dissipating area of the first flat shell body  11  is larger than the sum of the absorbing areas of the second flat shell bodies  12 . 
     The heat pipe  13  has a pipe wall  131 , a first extension portion  132 , and a second extension portion  133  opposite to the first extension portion  132 . The first extension portion  132  forms a first open end  1321  and the second extension portion  133  forms a second open end  1331 . The heat pipe channel  134  and the heat pipe wick structure  135  are both disposed in the pipe wall  131  and between the first open end  1321  and the second open end  1331 . The first extension portion  132  of the heat pipe  13  extends from the first open end  114  into the first chamber  111  such that the first open end  1321  is pressed against the first wick structure  115  on the top side  1111  in the first chamber  111 . Further, the heat pipe wick structure  135  at the first open end  1321  is connected to the first wick structure  115  on the top side  1111  by a capillary connection. Also, the first open end  1321  is closed by the top side  1111  in the first chamber  111 . 
     Besides, the second extension portion  132  of the heat pipe  13  extends from the second open end  124  into the second chamber  121  such that the second open end  1331  is pressed against the second wick structure  126  on the bottom side  1211  in the second chamber  121 . Further, the heat pipe wick structure  135  at the second open end  1331  is connected to the second wick structure  126  on the bottom side  1211  in a capillary connection. Also, the second open end  1331  is closed by the bottom side  1211  in the second chamber  121 . 
     The first extension portion  132  and the second extension portion  133  of the heat pipe  13  are provided with a first throughhole  1322  and a second throughhole  1332 , respectively, both penetrating through the pipe wall  131 . The heat pipe channel  134  communicates with the first chamber  111  and the second chamber  121  through the first throughhole  1322  and the second throughhole  1332 , respectively. 
     In one embodiment, as shown in  FIGS. 3A and 3B , the pipe wall  131  of the heat pipe  13  has an inner surface  136  facing the heat pipe channel  134 . The inner surface  136  is an internal smooth and circular surface. The heat pipe wick structure  135  is disposed on the inner surface  136 . However, in an alternative embodiment as shown in  FIGS. 4A and 4B , the inner surface  136  is provided with a plurality of ribs  137  disposed spacedly and a groove  138  is disposed between each two adjacent ribs  137 . The ribs  137  and the grooves  138  are interlaced with one another and extend along a longitudinal direction of the heat pipe  13 . The heat pipe wick structure  135  is formed on the ribs  137  and the grooves  138 . Thus, the area of the heat pipe wick structure  135  increases. 
     The first and second wick structures  115 ,  126  and the heat pipe wick structure  135  are made of a porous structure such as the metal sintered powder, woven mesh, groove, or fiber bundle, which can provide capillary force to drive the working fluid  125  to flow. 
     The term of “capillary connection” in the specification means that the first and second wick structures  115 ,  126  are physically touched by, pressed against, or connected to the heat pipe wick structure  135  such that the pores of the first and second wick structures  115 ,  126  communicate with those of the heat pipe wick structure  135 . In this way, the capillary force can pass or deliver from the heat pipe wick structure  135  to the first and second wick structures  115 ,  126 ; the cooled working fluid  125  can flow back from the first chamber  111  to the second chamber  121  by the capillary force. 
     In operation, the second outer bottom surface  122  of each of the second flat shell bodies  12  touches a heat source such as a CPU, a MPU, a GPU, or other electronic components. The heat generated by each heat source is transferred to the corresponding second chamber  121  through the second outer bottom surface  122 . The working fluid  125  in the second chamber  121  is heated and vaporized to transform into a vapor state and then flows through the second throughhole  1332  into the heat pipe channel  134  and then through the first throughhole  1322  into the first chamber  111 . Then, the working fluid  125  dissipates the heat by means of the first outer top surface  113 . After the working fluid  125  dissipates the heat, it transforms into a liquid state. Then, the working fluid  125  splits and flows to each heat pipe channel  134  by means of the capillary connection between the first wick structure  115  in the first chamber  111  and the heat pipe wick structure  135  at the first open end  1321  of the heat pipe  13 . After that, the working fluid  125  flows back to the second open end  1331  of the heat pipe  13  by gravity and the capillary force of the heat pipe wick structure  135  and then flows back to the second chambers  121  by means of the capillary connection between the heat pipe wick structure  135  and the second wick structure  126 . That is, the working fluid  125  in the plural second flat shell bodies  12  flows through the heat pipes  13  into the first flat shell body  11  to merge and dissipate the heat. After dissipating the heat, the working fluid  125  splits and flows back to the second flat shell bodies  12  from the first flat shell body  11  through the corresponding heat pipes  13 . 
     In addition,  FIGS. 5A and 5B  show another alternative embodiment of the present invention. As shown in  FIGS. 5A and 5B , a supporting cylinder  14  is disposed in the heat pipe channel  134  of the above-mentioned heat pipe  13  and extends along a longitudinal direction of the heat pipe  13 . Two opposite ends of the supporting cylinder  14  are individually pressed against the top side  1111  in the first chamber  111  and the bottom side  1211  in the second chamber  121 . The outer surface of the supporting cylinder  14  is provided with a cylindrical wick structure  141  made of metal sintered powder and/or grooves. The cylindrical wick structure  141  following the two opposite ends of the supporting cylinder  14  are individually pressed against the first wick structure  115  on the top side  1111  in the first chamber  111  and the second wick structure  126  on the bottom side  1211  in the second chamber  121 . By means of such an arrangement, the heat pipes  13  and the supporting cylinders  14  are located between and support the first flat shell body  11  and the second flat shell bodies  12 . Also, the cooled working fluid  125  in the first chamber  111  flows back to the respective second chambers  121  through the heat pipe wick structure  135  and the cylindrical wick structure  141 . 
     The supporting cylinders  14  and the cylindrical wick structure  141  have preferably circular cross sections which are the same as that of the heat pipe  13  and the circular cross sections are concentric circles. The cross sectional diameter of the supporting cylinders  14  is preferably smaller than that of the heat pipe  13  and there is thus a channel space existing between the inner surface  136  of the pipe wall of the heat pipe  13  and the outer surface of the supporting cylinder  14  and the cylindrical wick structure  141  to allow the working fluid  125  to flow in the heat pipe channel  134 . The above-mentioned supporting cylinder  14  is made of metal such as copper. However, in another alternative embodiment, the supporting cylinder  14  is made of metal sintered powder which itself is a wick structure and thus the above-mentioned cylindrical wick structure  141  can be omitted. 
     Please continue to refer to  FIGS. 6A and 6B . The first outer top surface  113  of the first flat shell body  11  is selectively provided with a heat sink unit like a cooler or a fan; a heat sink  21  is disposed as shown in  FIG. 6A  in a preferred embodiment. However, in another embodiment, two heat sinks  21   a ,  21   b  are disposed on the first outer top surface  113  of the first flat shell body  11 . These two heat sinks  21   a ,  21   b  are spaced to each other and individually correspond to two second flat shell bodies  12 . Because each of the heat sinks  21 ,  21   a , and  21   b  has plural fins to increase the contact area with air, the heat on the first outer top surface  113  can be dissipated quickly through the heat sinks  21 ,  21   a , and  21   b.    
     By means of the above arrangement, the working fluid  125  in each of the second flat shell bodies  12  flows into the first flat shell body  11  through the corresponding heat pipes  13  and dissipates the heat through the first outer top surface  113  of the first flat shell body  11  and then flows back to the second flat shell bodies  12  from the first flat shell body  11  through the heat pipes  13  by gravity and capillary force. Due to the dual effect of the gravity and capillary force, the reflow speed of the working fluid  125  increases. As a result, the liquid-vapor circulation is enhanced and the efficiency of the heat dissipation is thus enhanced. On the other hand, because the heat dissipating area of the first outer top surface  113  of the first flat shell body  11  is larger than the heat absorbing area of the second outer bottom surface  122  of each of the second flat shell bodies  12  or larger than the sum of the absorbing areas of the second flat shell bodies  12 , after the working fluid  125  in the second flat shell bodies  12  merges and flows into the first flat shell body  11 , the efficiency of the heat dissipation is further increased by means of the large heat dissipating area of the first shell body  11 . 
     The above-mentioned embodiments are only the preferred ones of the present invention. All variations regarding the above method, shape, structure, and device according to the claimed scope of the present invention should be embraced by the scope of the appended claims of the present invention.