Combination Heat Dissipation Structure

The present application is a continuation application of U.S. patent application Ser. No. 18/387,854, filed on Nov. 8, 2023.

The present invention relates to a combination heat dissipation structure, and more particularly, to a combination heat dissipation structure that has enhanced structural strength and allows a working fluid to flow back from a condensing zone to a vaporizing zone more efficiently.

To satisfy customers' increasing demands for good heat dissipation of electronic devices, such as computers or servers, a three-dimensional (3D) vapor chamber (VC) structure has been developed. Compared to a conventional two-dimensional (2D) vapor chamber, the 3D vapor chamber advantageously has higher density of integration, higher vapor diffusion rate, smaller thermal resistance, and higher upper limit of heat dissipation. In view of the constantly increased density of integration of chips in the electronic devices and the increasing requirement for heat dissipation, the conventional heat pipe and/or vapor chamber can no longer suffice the heat dissipation requirement for the high heat flux electronics, the 3D vapor chamber has been widely applied in the field of electronic device heat dissipation and gradually replaces the heat pipe and/or the vapor chamber that are used individually.

Please refer tothat is a cross-sectional view of a conventional 3D vapor chamber structure. As shown, the conventional 3D vapor chamber structureconsists of a plurality of pipesand a vapor chamber. The vapor chamberincludes an upper plate memberand a lower plane member, which are closed to each other to define a flat chamberbetween them. The flat chamberhas a working fluid (not shown) filled therein. The upper plate memberis provided with at least one opening, which extends through the upper plate memberto communicate with the flat chamber. The openinghas a rim that extends upward to form a ring portion. A first wick structureand a second wick structureare provided on an inner wall surface of the upper and the lower plate member,, respectively. And, a plurality of supporting membersis provided in the flat chamberto support and space the upper and the lower plate member,from one another. The supporting membersand the openingsare arranged in a staggered manner to space from one another.

The pipehas two ends, one of which is a closed endand the other is an open end. The pipeinternally defines a tubular chamberbetween the closed endand the open end. The open endof the pipeis inserted through the openingto connect with the upper plate member, and a joint between the ring portionof the openingand the open endof the pipeis fixedly connected by welding. The tubular chamberin the pipeis communicable with the flat chambervia the open endof the pipe. A third wick structureis provided on an inner wall surface of the tubular chamber.

The third wick structurein the pipemay or may not be in contact with the first wick structure, which is provided on the inner wall surface of the upper plate memberin the vapor chamber.

The working fluid condensed in the pipecan flow back from the closed endto a vaporizing zone in the vapor chamberin two ways. In the first way, the condensed working fluid in the pipeflows through the open endof the pipeto the first wick structurenear the openingformed on the upper plate memberand is then collected at the first wick structure. When the collected working fluid reaches a predetermined volume, it drops into the vaporizing zone due to gravity. In the second way, the working fluid flows back to areas near the openingand diffuses horizontally with the aid of the first wick structure. When the diffused working fluid encounters the supporting members, it flows downward along the outer surfaces of the supporting membersand reaches the second wick structure, from where the working fluid flows back to the vaporizing zone in the vapor chamber. Since the supporting membersare respectively located at a distance from the opening, the working fluid has to flow through a considerably long path before it reaches the vaporizing zone, resulting in low flow-back efficiency. If the time and the path for the working fluid to flow back to the vaporizing zone are too long, and the working fluid cannot return in time, the vaporizing zone tends to experience dry burning due to insufficient working fluid therein.

Further, the pipeand the vapor chamberare horizontally fixedly welded to each other only at the joint between the ring portionand the open end. That is, the pipeand the vapor chamberonly have a line contact formed between them. The portion of the pipethat extends into the flat chamberof the vapor chamberis not vertically supported or held in place by any structure. When the pipeis subjected to a vertical impact, or when the closed endof the pipehas radiation fins mounted thereon, it is very possible that the pipemay separate from the vapor chamber, or become bent or even broken, resulting in leakage of the working fluid from the conventional 3D vapor chamber structure. The above problems in the conventional 3D vapor chamber structuremust be solved as soon as possible.

To effectively solve the problems in the prior art, it is a primary object of the present invention to provide a combination heat dissipation structure consisting of a vapor chamber and at least one heat pipe. The assembled vapor chamber and heat pipe have enhanced overall structural strength and allow condensed working fluid to flow back from the heat pipe to the vapor chamber more efficiently.

To achieve the above and other objects, the combination heat dissipation structure according to the present invention includes a vapor chamber and at least one heat pipe.

The vapor chamber internally defines an airtight chamber filled with a working fluid. The vapor chamber is formed of an upper plate member and a lower plate member, which are closed to each other to define the airtight chamber between them. Two opposing inner side surfaces of the upper and the lower plate member that face toward the airtight chamber are provided with a first and a second wick structure, respectively.

The upper plate member of the vapor chamber is provided with at least one through hole, which is communicable with the airtight chamber. A plurality of annular elements are provided within the airtight chamber. Each annular element is a porous structure having an upper end surface and a lower end surface, which are in contact with the first and the second wick structure, respectively. Furthermore, the plurality of annular elements are positioned to correspond to the through hole.

The heat pipe has two ends, one of which is a closed end and the other is an open end. The heat pipe internally defines a heat pipe chamber extending between the closed and open ends to communicate with the airtight chamber via the open end. That is, the open end of the heat pipe is inserted into the through hole on the upper plate member of the vapor chamber to enter the airtight chamber and contact the first wick structure. The open end of the heat pipe inserted into the airtight chamber is axially supported and positioned by the plurality of annular elements disposed beneath the wick structure corresponding to the through hole.

According to the present invention, each through hole on the vapor chamber has a plurality of annular elements positioned to correspond to it. The plurality of annular elements not only provide axial support and positioning for the heat pipe inserted into the airtight chamber, but also allow the working fluid condensed in the heat pipe chamber to pass through them and directly and quickly flow back to a vaporizing zone in the vapor chamber. Therefore, the present invention can improve the efficiency of the working fluid returning to the vaporizing zone, prevent dry burning caused by an overly long return path, and enhance the structural strength of the combined vapor chamber and heat pipe assembly.

The present invention will now be described with some preferred embodiments thereof. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals.

Please refer to, which are exploded perspective view, assembled cross-sectional view and top view, respectively, of a combination heat dissipation structure according to a preferred embodiment of the present invention. As shown, the combination heat dissipation structure of the present invention includes a vapor chamber, and at least one heat pipe.

The vapor chamberis formed by closing an upper plate memberand a lower plate memberto each other, such that an airtight chamberis defined in the vapor chamberbetween the upper and the lower plate member,. The airtight chamberis filled with a working fluid (not shown). Two opposing inner side surfaces of the upper plate memberand the lower plate memberthat correspondingly face toward the airtight chamberare provided with a first wick structureand a second wick structure, respectively. The upper plate memberis provided with at least one through hole, which extends through the upper plate memberin a thickness direction thereof. Each through holehas an upward (i.e. outward) protruded flangeextending along a rim of the through hole. The first wick structureis so arranged that it is spread to a location closely adjacent to the through hole.

The through holecommunicates the airtight chamberwith an outer side of the vapor chamberand is provided mainly for one heat pipeto insert thereinto, such that the heat pipeand the vapor chamberare joined together. The inner side surface of the lower plate memberof the vapor chamberforms a vaporizing zone in the vapor chamberand has the above-mentioned second wick structureand a plurality of annular elementsprovided thereon.

The annular elementis a porous structure to provide capillary force to facilitate the working fluid in a liquid phase to flow back to the vaporizing zone in the vapor chamber. The annular elementhas an upper end surfaceand a lower end surface, and an axial bore. The axial boreis formed on the annular elementto axially extend through the upper and the lower end surface,, such that the annular elementforms a hollow structure. The upper and the lower end surface,of the annular elementare in contact with the first and the second wick structure,, respectively.

Please refer to. When two or more annular elementsare arranged corresponding to a single through hole, the annular elementsare disposed adjacent to one another with their outer edges in contact with each other. In this case, portions or areas of the upper end surfacesof the annular elementsthat overlap the through holemay serve to support the heat pipethat is perpendicularly inserted into the through hole.

The heat pipehas two ends, one of which is a closed endand the other is an open end, and internally defines a heat pipe chamberextending between the closed endand the open end. A third wick structureis provided on the entire inner wall surface of the heat pipe chamber. The open endof the heat pipeis correspondingly inserted into the through holeformed on the vapor chamberto enter the airtight chamberdefined in the vapor chamber, such that the heat pipeis joined to the vapor chamber. When the heat pipeand the vapor chamberare assembled in the above-described manner, the heat pipe chamberand the airtight chamberare communicable with each other.

The open endof the heat pipeis in contact with an upper side of the first wick structurein the airtight chamberof the vapor chamber, and a lower side of the first wick structureis in contact with the upper end surfaceof the annular element. Therefore, the open endof the heat pipeextended into the airtight chambervia the through holeis axially supported on the upper end surfaceof the annular element. That is, the open endof the heat pipeis axially interfered by the annular element, such that the heat pipecan no longer axially move deeper into the airtight chamberin the vapor chamber. With the annular elementthat provides axial propping, locating, and supporting to the heat pipejoined to the vapor chamber, the assembly of the heat pipeand the vapor chamberhas increased structural strength.

The working fluid vaporized in the airtight chamberof the vapor chambercan diffuse directly toward the heat pipe chamberin the heat pipe, allowing the heat carried by the vaporized working fluid to be dissipated into the surrounding air at a location remote from the vapor chamber. Since the annular elementis located correspondingly to the open endof the heat pipe, the working fluid condensed in the heat pipe chambercan be directly guided by the annular elementto flow back to the second wick structureprovided in the vaporizing zone in the vapor chamber. With this arrangement, the path and the time for the condensed working fluid to flow from the heat pipeback to the vaporizing zone are largely shortened, enabling the working fluid to flow back faster and allowing continuous and stable two-phase heat exchange of the working fluid between the liquid phase and the vapor phase thereof to avoid the occurrence of dry burning in the vapor chamber.

The first wick structure, the second wick structure, and the third wick structuremay be formed of a sintered powder material, a woven mesh, a grid structure, or a fibrous structure. Furthermore, the first wick structure, the second wick structure, and the third wick structurecan be formed using the same type or different types of wick structures.

The lower plate memberof the vapor chamberincludes a plurality of supporting posts that upwardly protrude from a bottom inner side of the lower plate member. The supporting posts and the through holesare arranged in a staggered manner. The annular elementcan be fitted around one supporting post while overlapping a corresponding through hole.

In the present invention, the provision of the annular elementnot only enables precise control of the depth to which the heat pipecan be axially inserted into the airtight chamberfrom an outer side of the vapor chamber, but also provides effective axial support and positioning for the heat pipe, thereby increasing the structural strength of the combined heat pipeand vapor chamber.

Further, the annular elementin the present invention serially connects the first wick structure, the second wick structure, and the third wick structureprovided in the vapor chamberand the heat pipe, thereby enabling the storage of working fluid and facilitating the return flow of the working fluid from the heat pipeto the vapor chamber. By providing the annular element, the path and the time required for the condensed working fluid in the heat pipe chamberto flow from the heat pipethrough the annular elementback to the second wick structurein the vaporizing zone of the vapor chamberare largely shortened. Therefore, continuous and stable two-phase heat exchange between the heat pipeand the vapor chambercan be maintained, thereby avoiding dry burning in the vaporizing zone of the vapor chamberand enhancing heat exchange efficiency.

The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.