Patent Publication Number: US-2017367216-A1

Title: Water cooling device

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a water cooling device and in particular to a water cooling device which has a thinning effect. 
     Description of Prior Art 
     As the operating capacity of the electronic device increases, the electronic components disposed therein will generate large amount of heat during operation. Heat sinks or cooling fins are generally required to be installed on the electronic components to increase the heat dissipation area and thus enhance heat dissipation efficiency. However, because the heat dissipation efficiencies of the heat sinks and the cooling fins are limited, a traditional water cooling device of the prior art technology is used to enhance the heat dissipation efficiency. 
     The traditional water cooling device can perform heat exchange between the heat generating device such as a processing unit or a graphics processing unit and a cooling liquid in the water cooling device. Then, the cooling liquid is circulated by a pump in the water cooling device. Also, the water cooling device is connected to a heat sink through plural pipes such that the cooling liquid is used to perform heat exchange and cyclic heat dissipation between the heat sink and the water cooling device. As a result, the heat generating device can quickly dissipate the heat. 
     In the above traditional prior art water cooling device, in order to protect the stator assembly of the pump from damage by contact with liquid, the stator assembly is disposed outside the water cooling device and the rotor assembly which guides the cooling liquid to circulate in the water cooling device is disposed in a chamber of the water cooling device. The stator assembly and the rotor assembly are magnetically excited to operate through the outer shell of the water cooling device. Due to the concern of the structural strength of the outer shell of the water cooling device, the outer shell has a specific thickness. Consequently, the gap caused by the thickness of the outer shell of the water cooling device between the rotor assembly and the stator assembly influences the operation efficiency of the pump, which causes the problems of poor efficiency of whole heat dissipation of the water cooling device and an excessive volume of the entire water cooling device. 
     SUMMARY OF THE INVENTION 
     Thus, to effectively overcome the above problems, one objective of the present invention is to provide a water cooling device which can achieve a thinning effect. 
     Another objective of the present invention is to provide a water cooling device which can reduce the thickness gap between the stator and the corresponding rotor and decrease the entire volume thereof. 
     Yet another objective of the present invention is to provide a water cooling device which can reduce the flow speed to prevent eddies (or turbulence) by means of a first inclined surface of a water channel and a second inclined surface on an internal wall of a heat exchange chamber in which there is a step difference formed between the first and the second inclined surfaces. Also, the second inclined surface is adjacent to, connected to, and opposite to the first inclined surface 
     To achieve the above objectives, the present invention provides a water cooling device which comprises a liquid storing shell body and a pump. The liquid storing shell body has a liquid chamber, an inlet, and an outlet; the liquid chamber communicates with the inlet and the outlet to allow a cooling liquid to flow through the interior thereof. The pump is used to circulate the cooling liquid and comprises a stator and a rotor. The stator has a coil set disposed electrically on a circuit board. The circuit board and the coil set thereon are both disposed on at least one inner wall of the liquid chamber or integrally overmolded in the liquid storing shell body. The circuit board and the coil set are both isolated from the cooling liquid. The rotor and a propeller oppositely connected to the rotor are received in the liquid chamber and exposed in the cooling liquid. The propeller is provided with a plurality of blades made of metal. At least one magnetic pole region is magnetized on each of the blades opposite to the coil set. The magnetic pole region of the each of the blades is inductively excited by the coil set. 
     In one embodiment, an upper edge or a lower edge of the each of the blades is axially magnetized to form the magnetic pole region. A protective film surrounding the circuit board and the coil set is disposed on an internal top wall or an internal bottom wall of the liquid chamber and corresponds to the magnetic pole regions of the blades. 
     In one embodiment, a front edge of the each of the blades is radially magnetized to form the magnetic pole region. A protective film surrounding the circuit board and the coil set is disposed on an internal side wall of the liquid chamber and corresponds to the magnetic pole regions of the blades. 
     In one embodiment, the circuit board and the coil set are integrally overmolded inside a top portion or a bottom portion of the liquid storing shell body and correspond to the magnetic pole regions of the blades. The circuit board and the stator are disposed outside the liquid chamber. The liquid storing shell body isolates the cooling liquid from the stator and the circuit board. 
     In one embodiment, the circuit board and the coil set are integrally overmolded inside a side portion of the liquid storing shell body and correspond to the magnetic pole regions on the front edges of the blades. The circuit board and the stator are disposed outside the liquid chamber. The liquid storing shell body isolates the cooling liquid from the stator and the circuit board. 
     In one embodiment, the rotor has a shaft. One end of the shaft is connected to the propeller and the other end of the shaft is axially disposed on an internal wall of the liquid chamber. The inlet and the outlet are individually disposed on two sides of the liquid storing shell body. 
     In one embodiment, the water cooling device further comprises a heat exchange component oppositely connected to the liquid storing shell body. The heat exchange component has a heat contact surface and a heat exchange surface which contacts the cooling liquid in the liquid chamber. 
     In one embodiment, the water cooling device further comprises a heat exchange component oppositely connected to the liquid storing shell body. The liquid storing shell body further comprises a separation part, at least one throughhole, and a water channel. The separation part is formed at the middle of the liquid storing shell body. The separation part, the liquid storing shell body, and the heat exchange component together define the liquid chamber and a heat exchange chamber communicating with the outlet. The throughhole is formed on the separation part and communicates with the inlet and the liquid chamber which is disposed above the heat exchange chamber. The water channel is disposed between the liquid chamber and an internal side wall of the liquid chamber and penetrates through the separation part to communicate with the heat exchange chamber. 
     In one embodiment, the water channel has a first inclined surface extending from the bottom of the water channel in the liquid chamber to penetrate through the separation part and slope downward. A second inclined surface is disposed on an internal wall of the heat exchange chamber opposite to the water channel. The second inclined surface is adjacent to, connected to, and opposite to the first inclined surface. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
         FIG. 1  is a perspective exploded view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 2  is a perspective assembled view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 2A  is a cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 2B  is a partial enlarged cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 3A  is an embodiment of the cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 3B  is another embodiment of the cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 4A  is yet another embodiment of the cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 4B  is still yet another embodiment of the cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 4C  is another embodiment of the cross-sectional view of the water cooling device according to the first embodiment of the present invention; 
         FIG. 5A  is a perspective exploded view of the water cooling device according to the second embodiment of the present invention; 
         FIG. 5B  is a cross-sectional view of the water cooling device according to the second embodiment of the present invention; 
         FIG. 6  is an applicable embodiment of the water cooling device according to the second embodiment of the present invention; 
         FIG. 7  is a perspective exploded view of the water cooling device according to the third embodiment of the present invention; 
         FIG. 8A  is a perspective assembled view of the water cooling device according to the third embodiment of the present invention; 
         FIG. 8B  is a cross-sectional view of the water cooling device according to the third embodiment of the present invention; and 
         FIG. 8C  is another embodiment of the cross-sectional view of the water cooling device according to the third 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 water cooling device, referring to  FIGS. 1, 2, and 2A  which show the perspective exploded view, the perspective assembled view, and the cross-sectional view of the water cooling device according to the first embodiment of the present invention, respectively. The water cooling device  1  comprises a liquid storing shell body  10  and a pump  20 . The liquid storing shell body  10  is made of plastic and has a liquid chamber  101 , an inlet  102 , an outlet  103 , and a bottom cover  106 . The bottom side of the liquid storing shell body  10  is directly connected to an end surface of the bottom cover  106  to seal the liquid chamber  101 . The liquid chamber  101  communicates with the inlet  102  and the outlet  103  to allow a cooling liquid to flow through the interior thereof. The inlet  102  and the outlet  103  are individually disposed on two sides of the liquid storing shell body  10 . A washer  109  is disposed between the bottom cover  106  and the liquid storing shell body  10 . The washer  109  is used to increase the sealing strength between the liquid storing shell body  10  and the bottom cover  106  to prevent the cooling liquid from seeping out of the liquid chamber  101 . The above-mentioned bottom cover  106  is part of the liquid chamber  101 . The combination of the bottom cover  106  and the liquid chamber  101  is made by embedment, used for explanation, and is not limited to this. In a specific embodiment, the above-mentioned combination can be made by adhesion or by screwing. 
     The pump  20  is used to circulate the cooling liquid and comprises a stator  201 , a rotor  202 , and a propeller  203 . The stator  201  has a coil set  2011  which is formed on a circuit board  30  by disposition, layout, etching, or printing in the current embodiment. Also, the coil set  2011  is disposed electrically on one side of the circuit board  30 . In a specific embodiment, the coil set  2011  can be formed on one side of the circuit board  30  by stacking or by layout. In the current embodiment, the circuit board  30  and the coil set  2011  thereon are both disposed on at least one inner wall of the liquid chamber  101 ; the circuit board  30  and the coil set  2011  are both isolated from the cooling liquid. Besides, a protective film  31  (or a coating) surrounds the circuit board  30  and the coil set  2011 ; the protective film  31  (or the coating) is used to isolate the cooling liquid from the stator  201  and the circuit board  30 . In the current embodiment shown in  FIGS. 2A and 2B , the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are adhered to each other and are disposed on an internal top wall of the liquid chamber  101 . In an alternative embodiment shown in  FIG. 3A , the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are adhered to each other and are disposed an internal bottom wall of the liquid chamber  101 . In an alternative embodiment shown in  FIG. 3B , the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are adhered to each other and are disposed an internal side wall of the liquid chamber  101 . The above-mentioned circuit board  30  is a flexible printed circuit board (FPCB) or a printed circuit board (PCB), one end of which is electrically connected to a connecting wire set (not shown). One end of the connecting wire set is electrically connected to the circuit board  30  and the other end of the connecting wire set extends from the liquid chamber  101  and penetrates through the liquid storing shell body  10  to the outside thereof such that the other end of the connecting wire set is connected to a mother board (or a power supply) correspondingly. The place where the other end of the connecting wire set penetrates through the liquid storing shell body  10  from the liquid chamber  101  is sealed to prevent the cooling liquid from seeping out of the liquid chamber  101 . In an alternative embodiment, one end of the connecting wire set is electrically connected to the circuit board  30  and the other part (i.e., the portion between the one end and the other end of the connecting wire set) are integrally overmolded in the liquid storing shell body  10  and the other end of the connecting wire set is exposed outside the liquid storing shell body  10  to be correspondingly connected to the mother board (or the power supply, not shown). Moreover, the connecting wire set in the current embodiment includes power wires and control signal wires. The power wires are used to provide power for the electronic components on the circuit board  30  and the pump  20 ; the control signal wires are used to control the rotating speed of the pump (or to control the switching on/off of the pump at the same time). 
     In addition, the rotor  202  is connected to the propeller  203  both of which are received in the liquid chamber  101  and exposed in the cooling liquid such that the rotor  202  corresponds to the stator  201  and the rotor  202  is driven to rotate the propeller  203 . Then, the propeller  203  stirs the cooling liquid in the liquid chamber  101 . The cooling liquid flowing in through the inlet  102  is moved by the propeller  203  to flow out through the corresponding outlet  103 . The rotor  202  has a shaft  2021 . One end of the shaft  2021  is connected to the propeller  203  and the other end of the shaft  2021  is axially disposed on the internal wall of the liquid chamber  101 . The propeller  203  is provided with a plurality of blades  2031  made of metal; at least one magnetic pole region  204  is magnetized on each of the blades  2031  opposite to the coil set  2011 . That is, in the current embodiment, an upper edge  2032  of each of the blades  2031  is axially magnetized to form the magnetic pole region  204 . The upper edges  2032  of each two adjacent blades  2031  have different magnetic pole regions  204  (a north pole or a south pole). The magnetic pole region  204  on the upper edge  2032  of each of the blades  2031  is inductively excited by the opposite coil set  2011  on the internal top wall of the liquid chamber  101 . Thus, the rotor  202  is driven to rotate. 
     In an alternative embodiment shown in  FIG. 3A , a lower edge  2033  of the each of the blades  2031  is axially magnetized to form the magnetic pole region  204  and the lower edges  2033  of each two adjacent blades  2031  have different magnetic pole regions  204  (a north pole or a south pole). The magnetic pole region  204  on the lower edge  2033  of each of the blades  2031  is inductively excited by the opposite coil set  2011  on the internal bottom wall of the liquid chamber  101 . In an alternative embodiment shown in  FIG. 3B , a front edge  2034  of the each of the blades  2031  is radially magnetized to form the magnetic pole region  204  and the front edges  2034  of each two adjacent blades  2031  have different magnetic pole regions  204  (a north pole or a south pole). The magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the opposite coil set  2011  on the internal side wall of the liquid chamber  101 . 
     In one embodiment, the above-mentioned circuit board  30  and the coil set  2011  thereon are integrally overmolded inside the liquid storing shell body  10 . The circuit board  30  and the stator  201  are disposed outside the liquid chamber  101 . The liquid storing shell body  10  isolates the cooling liquid from the stator  201  and the circuit board  30 . As shown in  FIG. 4A , the circuit board  30  and the coil set  2011  are integrally overmolded inside a top portion (close to the internal wall surface) of the liquid storing shell body  10 . The magnetic pole region  204  on the upper edge  2032  of each of the blades  2031  is inductively excited by the opposite coil set  2011  wrapped inside the top portion of the liquid chamber  101 . In an embodiment shown in  FIG. 4B , the circuit board  30  and the coil set  2011  are integrally overmolded inside a bottom portion of the liquid storing shell body  10 . The magnetic pole region  204  on the lower edge  2033  of each of the blades  2031  is inductively excited by the opposite coil set  2011  wrapped inside the bottom portion of the liquid chamber  101 . In an embodiment as shown in  FIG. 4C , the circuit board  30  and the coil set  2011  are integrally overmolded inside a side portion of the liquid storing shell body  10 . The magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the opposite coil set  2011  wrapped inside the side portion of the liquid chamber  101 . Thus, by means of the integral overmold structure of the circuit board  30  and the coil set  2011  inside the liquid storing shell body  10 , the waterproof and protection of stator  201  and the circuit board  30  can be achieved. Also, the thickness gap between the stator  201  and the corresponding rotor  202  can be effectively reduced (or shortened) to achieve the thinning effect. 
     A large magnetic component such as a magnet on the traditional rotor  202  can be replaced by means of the structural design of the present invention using a position (i.e., the upper edge  2032 , the lower edge  2033 , or the front edge  2034 ) on each of the blades  2031  to be magnetized to form the magnetic pole region  204  corresponding to the coil set  2011  on the circuit board  30 . As a result, the space to receive the traditional magnetic component can be omitted to decrease the entire volume of the liquid storing shell body  10  and to achieve the thinning effect. 
     Please refer to  FIGS. 5A and 5B , which show the perspective exploded view and the cross-sectional view of the water cooling device according to the second embodiment of the present invention, respectively. The structure, the connecting relation, and the effect of the current embodiment are roughly similar to those of the first embodiment and will not be repeated here. It is mainly the bottom cover  106  of the liquid storing shell body  10  of the first embodiment that is replaced with a heat exchange component  40  connected to the liquid storing shell body  10  to form the current embodiment. That is, the water cooling device  1  further comprises the above-mentioned heat exchange component  40 . One side surface of the heat exchange component  40  is connected to the bottom side of the liquid storing shell body  10  to seal the liquid chamber  101 . The sealing strength between the liquid storing shell body  10  and the heat exchange component  40  is increased using the washer  109  which is disposed between the liquid storing shell body  10  and the heat exchange component  40  to prevent the cooling liquid from seeping out of the liquid chamber  101 . Besides, the heat exchange component  40  is made of metal having high heat conductivity such as aluminum, copper, gold, or silver and has a heat contact surface  401  and a heat exchange surface  402 . The heat contact surface  401  is firmly attached to an opposite heat generating device  7  (e.g., a central processing unit or a graphic processing unit) and is used to transfer the heat received from the heat generating device  7  to the heat exchange surface  402  which is disposed in the liquid chamber  101  in which the heat exchange surface  402  contacts the cooling liquid in the liquid chamber  101 . 
     Moreover, the above-mentioned heat exchange component  40  has a plurality of cooling fins  404 . The cooling fins  404  are radially spaced on the heat exchange surface  402 , but not limited to this. By means of the disposition of the cooling fins  404  on the heat exchange surface  402 , the effect of the heat exchange surface  402  can be significantly enhanced. In addition, as shown in  FIG. 6 , the water cooling device  1  is connected to a heat dissipating device  5  to from a liquid cooling system. The heat dissipating device  5  is connected to and communicates with the inlet  102  and the outlet  103  of the water cooling device  1  through a plurality of flexible tubes  51  such that the propeller  203  in the liquid chamber  101  drives the cooling liquid to circulate and dissipate the heat in the liquid chamber  101  and the heat dissipating device  5 . Also, the heat dissipating device  5  can be connected to a fan  6  to facilitate the heat dissipation of the heat dissipating device  5 . 
     When the heat contact surface  401  of the heat exchange component  40  absorbs the heat generated by the heat generating device  7  and transfers it to the heat exchange surface  402 , heat transfer is performed between the heat exchange surface  402  and the cooling liquid in the liquid chamber  101  such that the cooling liquid takes away the heat on the heat exchange surface  402  and the cooling fins  404  and flows out of the liquid storing shell body  10  through the outlet  103  and thus the effect of heat dissipation is achieved. As a result, by means of the design of the water cooling device  1  of the present invention, the thinning effect and the volume reduction of the entire liquid storing shell body  10  can be achieved and further the waterproof of the stator  201  can be achieved and the thickness gap between the stator  201  and the rotor  202  can be effectively reduced (or shortened). 
     In the current embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on the internal top wall of the liquid chamber  101 . The magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the opposite coil set  2011  on the internal top wall of the liquid chamber  101 . In an alternative embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on the heat exchange surface  402  (i.e., the above-mentioned internal bottom wall of the liquid chamber  101 ) and the magnetic pole region  204  on the lower edge  2033  of each of the blades  2031  is inductively excited by the coil set  2011  on the opposite internal bottom wall (i.e., the heat exchange surface) of the liquid chamber  101 . In an alternative embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on the internal side wall of the liquid chamber  101  and the magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the coil set  2011  on the opposite internal side wall of the liquid chamber  101 . 
     In an embodiment, the circuit board  30  and the coil set  2011  are integrally overmolded inside the top portion of the liquid storing shell body  10  and the magnetic pole region  204  on the upper edge  2032  of each of the blades  2031  is inductively excited by the corresponding coil set  2011  wrapped inside the top portion of the liquid chamber  101 . In an embodiment, the circuit board  30  and the coil set  2011  are integrally overmolded inside the side portion of the liquid storing shell body  10 . The magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the corresponding coil set  2011  wrapped inside the side portion of the liquid chamber  101 . 
     Please refer to  FIGS. 7 and 8A , which show the perspective exploded view and the perspective assembled view of the water cooling device according to the third embodiment of the present invention, respectively and also refer to  FIG. 8B . The structure, the connecting relation, and the effect of the current embodiment are roughly similar to those of the first embodiment and will not be repeated here. The water cooling device  1  in the second embodiment is redesigned to have an upper chamber and a lower chamber (i.e., a liquid chamber  101  and a heat exchange chamber  403 ); the inlet  102  and the outlet  103  of the liquid storing shell body  10  are redesigned on the top cover  105  to form the current embodiment. That is, the above-mentioned liquid storing shell body  10  has a top cover  105 , a separation part  104 , at least one throughhole  1041 , and a water channel  107 . The top end of the liquid storing shell body  10  is connected to one end surface of the top cover  105  to seal the liquid chamber  101 . Another washer  109  is disposed between the liquid storing shell body  10  and the top cover  105  to increase the sealing strength between the liquid storing shell body  10  and the top cover  105  to prevent the cooling liquid from seeping out of the liquid chamber  101 . 
     The separation part  104  is formed at the middle of the liquid storing shell body  10 . The separation part  104 , the liquid storing shell body  10 , and the heat exchange component  40  together define a heat exchange chamber  403 . The above-mentioned liquid chamber  101  is disposed above the heat exchange chamber  403 . The liquid chamber  101  is above the separation part  104  and the heat exchange chamber  403  is under the separation part  104 . The above-mentioned throughhole  1041  is expressed as a throughhole  1041  in the current embodiment and is formed at the middle of the separation part  104  and communicates with the inlet  102  of the liquid storing shell body  10  and the liquid chamber  101 . The above-mentioned separation part  104  has a guiding channel  1042  formed therein and disposed between the liquid chamber  101  and the heat exchange chamber  403 . The guiding channel  1042  communicates with the inlet  102  of the liquid storing shell body  10  and the liquid chamber  101  to guide the cooling liquid entering from the inlet  102  to enter the liquid chamber  101  above through the throughhole  1041  in which the separation part  104  and the top cover  105  are part of the liquid storing shell body  10 . 
     The above-mentioned water channel  107  disposed between the liquid chamber  101  and an internal side wall of the liquid chamber  101  penetrates through the separation part  104  to communicate with the heat exchange chamber  403 , as shown in  FIG. 7 . The water channel  107  runs between the liquid chamber  101  and the internal side wall opposite to the liquid chamber  101  to form an arc-like shape and is used to guide the cooling liquid driven by the propeller  203  in the liquid chamber  101  to the heat exchange chamber  403 . Then, the cooling liquid in the heat exchange chamber  403  flows out via the corresponding outlet  103 . The water channel  107  has a first inclined surface  1071  extending from the bottom of the water channel  107  in the liquid chamber  101  to penetrate through the separation part  104  and slope downward. A second inclined surface  405  is disposed on an internal wall of the heat exchange chamber  403  opposite to the water channel  107 . The second inclined surface  405  is adjacent to, connected to, and opposite to the first inclined surface  1071 . The elevation of the first inclined surface  1071  is higher than that of the second inclined surface  405  such that a step difference is formed between the first and the second inclined surfaces  1071 ,  405 . In the current embodiment, the first inclined surface  1071  is roughly perpendicular to the second inclined surface  405 , but not limited to this. 
     Therefore, the usage of the first and second inclined surfaces  1071 ,  405  can reduce the flow speed of the cooling liquid in the water channel  107  which is then guided to the heat exchange chamber  403 . That is, the reduction of the flow speed can be achieved through the first and second inclined surfaces  1071 ,  405 . Besides, the flow of the cooling liquid is made smooth and further eddies (or turbulence) can be prevented when the cooling liquid just flows into the heat exchange chamber  403  and the bubbles caused by the impact of the cooling liquid just entering the heat exchange chamber  403  can be decreased. 
     In the current embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on the internal side of the top cover  105  of the liquid storing shell body  10  (i.e., the internal top wall of the liquid chamber  101 ). The magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the opposite coil set  2011  on the internal top wall of the liquid chamber  101  (i.e., the internal side of the top cover  105  of the liquid storing shell body  10 ). In an alternative embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on a side of the separation part  104  opposite to the top cover  105  (i.e., the internal bottom wall of the liquid chamber  101 ) and the magnetic pole region  204  on the lower edge  2033  of each of the blades  2031  is inductively excited by the coil set  2011  on the opposite internal bottom wall of the liquid chamber  101 . In an alternative embodiment, the circuit board  30  and the coil set  2011  both surrounded by the protective film  31  are firmly adhered on the internal side wall of the liquid chamber  101  and the magnetic pole region  204  on the front edge  2034  of each of the blades  2031  is inductively excited by the coil set  2011  on the opposite internal side wall of the liquid chamber  101 . 
     In an embodiment as shown in  FIG. 8C , the circuit board  30  and the coil set  2011  are integrally overmolded inside the top portion of the liquid storing shell body  10  (i.e., inside the top cover  105  of the liquid storing shell body  10 ) and the magnetic pole region  204  on the upper edge  2032  of each of the blades  2031  is inductively excited by the opposite coil set  2011  wrapped inside the top cover  105  of the liquid storing shell body  10 . In an embodiment, the circuit board  30  and the coil set  2011  are integrally overmolded inside the separation part  104  of the liquid storing shell body  10  and the magnetic pole region  204  on the lower edge  2033  of each of the blades  2031  is inductively excited by the corresponding coil set  2011  wrapped inside the separation part  104  of the liquid storing shell body  10 . 
     Therefore, by means of the design of the water cooling device  1  of the present invention, the thinning effect and the volume reduction of the entire liquid storing shell body  10  can be achieved and further the waterproof of the stator  201  can be achieved and the thickness gap between the stator  201  and the rotor  202  can be effectively reduced (or shortened). 
     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.