Patent Publication Number: US-9429167-B2

Title: Heat dissipating fan

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat dissipating fan and, more particularly, to a heat dissipating fan with an automatic dust removing function. 
     2. Description of the Related Art 
     Conventional heat dissipating fans generally include a housing having an air inlet and an air outlet. An impeller is rotatably mounted in the housing and driven by a driving unit also mounted in the housing to draw in ambient air via the air inlet. The air currents drawn into the housing are concentrated before exiting the air outlet to a heat source in an electronic product. The temperature of the heat source during operation is, thus, lowered. However, dust carried by the air currents is liable to accumulate inside the housing at the air inlet, the air outlet, the blades of the impeller, etc., adversely affecting the air input and/or air output and, thus, adversely affecting the heat dissipating effect. 
       FIG. 1  shows a heat dissipating fan  9  including a housing  91  having an air inlet  911  and an air outlet  912 . An impeller  92  is mounted in the housing  91 . A plurality of fins  93  is mounted in the air outlet  912 . Air currents can be driven by the impeller  92  into the housing  91  via the air inlet  911 . The air currents pass through the fins  93  and the air outlet  912  to a heat source of an electronic product. An example of such a blower fan  9  is disclosed in Taiwan Patent No. 1229254. However, dust is liable to accumulate inside the housing  91  after a period of time of use. Since the spacing between the fins  93  is small, the dust is liable to accumulate between the fins  93 , significantly reducing the air output and requiring regular manual cleaning. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a heat dissipating fan that can remove dust automatically. 
     Another objective of the present invention is to provide a heat dissipating fan with reliable input and output of air by automatically removing dust. 
     The present invention fulfills the above objectives by providing, in a preferred aspect, a heat dissipating fan including a housing having a base and a sidewall coupled to the base. The sidewall defines a compartment. The housing further includes an air inlet, an air outlet, and a dust channel. The air inlet, the air outlet, and the dust channel are in communication with the compartment. A stator is coupled to the base of the housing. An impeller is rotatably coupled to the stator. A control element includes a driving circuit electrically connected to the stator and a rotating direction control circuit electrically connected to the driving circuit. 
     In another preferred aspect, a heat dissipating fan includes a housing having a base and a lateral wall coupled to the base. The lateral wall defines a compartment. The lateral wall includes an air inlet and an air outlet both in communication with the compartment. The air inlet also acts as a dust channel. A stator is coupled to the base of the housing. An impeller is rotatably coupled to the stator. A control element includes a driving circuit electrically connected to the stator and a rotating direction control circuit electrically connected to the driving circuit. 
     The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiments may best be described by reference to the accompanying drawings where: 
         FIG. 1  shows a perspective view of a conventional heat dissipating fan. 
         FIG. 2  shows an exploded, perspective view of a heat dissipating fan of a first embodiment according to the preferred teachings of the present invention. 
         FIG. 3  shows a top view of the heat dissipating fan of  FIG. 2  with a cover of the heat dissipating fan removed and with the heat dissipating fan rotating in a direction for heat dissipating purposes. 
         FIG. 4  shows a top view of the heat dissipating fan of  FIG. 2  with a cover of the heat dissipating fan removed and with the heat dissipating fan rotating in a reverse direction for dust removing purposes. 
         FIG. 5  shows a top view of another case of the heat dissipating fan of the first embodiment with a cover of the heat dissipating fan removed, with a dust guiding pipe attached to the heat dissipating fan, and with the heat dissipating fan rotating in a direction for dust removing purposes. 
         FIG. 6  shows an exploded, perspective view of a heat dissipating fan of a second embodiment according to the preferred teachings of the present invention. 
         FIG. 7  shows a top view of the heat dissipating fan of  FIG. 6  with the heat dissipating fan rotating in a direction for heat dissipating purposes. 
         FIG. 8  shows a cross sectional view of the heat dissipating fan of  FIG. 6 . 
     
    
    
     All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiments will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood. 
     Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “inner”, “outer”, “end”, “section”, “clockwise”, “counterclockwise”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIGS. 2 and 3 , a heat dissipating fan of a first embodiment according to the preferred teachings of the present invention generally includes a housing  1 , a stator  2 , an impeller  3 , and a control element  4 . The housing  1  can be mounted in a desired location of an electronic product, such as a face of a main board inside a computer. The stator  2  is mounted in the housing  1 . The impeller  3  is mounted in the housing  1  and rotatably coupled to the stator  2 . The control element  4  controls the impeller  3  to rotate in a direction for generating enough air for heat dissipating purposes or to rotate in a reverse direction for dust removing purposes by cooperating with the structure of the housing  1 . 
     Specifically, the housing  1  includes a base  11  and a sidewall  12  coupled to a side of the base  11  and defining a compartment  121 . The sidewall  12  includes an air inlet  122  and an air outlet  123  both in communication with the compartment  121 . The sidewall  12  further includes a dust channel  124  in communication with the compartment  121 . It can be appreciated that the sidewall  12  can include more than one dust channel  124 . 
     The stator  2  is mounted to the base  11  of the housing  1  and includes a coil unit  21  and a shaft seat  22 . The coil unit  21  is mounted around or integrally formed with an outer periphery of the shaft seat  22 . Alternatively, instead of being mounted to the base  11 , the shaft seat  22  of the stator  2  may integrally formed on the base  11 . 
     The impeller  3  includes a hub  31  and a plurality of blades  32 . The hub  31  is rotatably coupled to the shaft seat  22  of the stator  2 . The blades  32  are coupled to an outer periphery of the hub  31 . 
     The control element  4  includes a driving circuit  41  and a rotating direction control circuit  42 . The driving circuit  41  is electrically connected to the coil unit  21  of the stator  2 . The rotating direction control circuit  42  is electrically connected to the driving circuit  41 . The driving circuit  41  and the rotating direction control circuit  42  can be packaged in the same integrated circuit. Furthermore, the control element  4  can be integrated into the housing  1 . However, the control element  4  can be external to the housing  1  without adversely affecting control on the impeller  3 . 
     In use of the heat dissipating fan of the first embodiment according to the preferred teachings of the present invention, the heat dissipating fan is engaged with an electronic product with the air outlet  123  of the housing  1  facing a heat source of the electronic product that tends to generate heat during operation. The rotating direction control circuit  42  can send a rotating direction control signal to the driving circuit  41  to actuate the coil unit  21  of the stator  2  to create a magnetic field for driving the impeller  3  to rotate in a direction (such as the counterclockwise direction). Ambient air currents are drawn in via the air inlet  122 . The air currents are concentrated by the impeller  3  before passing through the air outlet  123  to the heat source of the electronic product for heat dissipating purpose ( FIG. 3 ). 
     Since dust is liable to accumulate inside the housing  1  (such as at the air inlet  122 , the air outlet  123 , the blades  32  of the impeller  3 , etc.) after a period of time of use, the rotating direction control circuit  42  can send another rotating direction control signal to the driving circuit  41  to actuate the coil unit  21  of the stator  2  to create a magnetic field for driving the impeller  3  to rotate in a reverse direction (such as the clockwise direction). Ambient air currents are drawn in via the air inlet  122  and then exit the housing  1  via the dust channel  124  ( FIG. 4 ). Thus, the dust accumulated inside the housing  1  can be expelled from the housing  1  to the environment together with the air currents, eliminating accumulation of the dust. Thus, the overall air input and output are not adversely affected, effectively enhancing the heat dissipating effect. 
     More specifically, the rotating direction control circuit  42  can control the timing of rotation of the impeller  3  in the counterclockwise or clockwise direction through the driving circuit  41 . As an example, the heat dissipating fan according to the teachings of the present invention can be set that the impeller  3  rotates in the counterclockwise direction for a period of time (such as an hour or two) immediately after the heat dissipating fan is turned on. Then, the impeller  3  is controlled to rotate in the clockwise direction for another period of time (such as 10 or 20 minutes) for automatic removal of dust. After the automatic dust removing operation, the impeller  3  is controlled to rotate in the counterclockwise direction for heat dissipating purposes. Namely, the rotational direction of the impeller  3  can continuously alternate between the counterclockwise and clockwise directions to complete functions of heat dissipating and dust removing alternatively. In another example, the heat dissipating fan according to the teachings of the present invention can be set that the impeller  3  rotates in the clockwise direction for a period of time for automatic dust removing operation immediately after the heat dissipating fan is turned on. Then, the impeller  3  is controlled to rotate in the counterclockwise direction for heat dissipating purposes. 
     By controlling the impeller  3  to rotate in a reverse direction with the rotating direction control circuit  42  via the driving circuit  41 , the heat dissipating fan of the first embodiment according to the preferred teachings of the present invention can automatically remove dust without adversely affecting the heat dissipating function. Thus, accumulation of dust inside the housing  1  is eliminated to avoid adverse affect to the overall heat dissipating effect. The heat dissipating effect is, thus, enhanced, and the service life of the electronic product is prolonged. 
     The heat dissipating fan according to the teachings of the present invention can incorporate additional features to perfect the functions. Particularly, with reference to  FIGS. 2 and 3 , the air outlet  123  of the housing  1  includes opposite first and second end edges  123   a  and  123   b.  The housing  1  defines a first plane P 1  including the first and second end edges  123   a  and  123   b.  The impeller  3  defines a second plane P 2  including a center of the hub  31 . The second plane P 2  is parallel to and spaced from the first plane P 1 . The compartment  121  is divided into an air outlet section  121   a  and a pressure accumulating section  121   b  by defining the first and second planes P 1  and P 2 . The air outlet section  121   a  is located between the first and second planes P 1  and P 2 . The pressure accumulating section  121   b  and the air outlet section  121   a  are located on opposite sides of the second plane P 2 . The air outlet  123  is located in the air outlet section  121   a . The dust channel  124  is located in the pressure accumulating section  121   b.  Thus, the dust channel  124  is away from the air outlet  123 . When the control element  4  controls the impeller  3  to rotate in the clockwise direction, the impeller  3  can drive the air currents from the air outlet section  121   a  to the pressure accumulating section  121   b  more thoroughly, so that the dust accumulated inside the housing  1  can be smoothly removed together with the air currents exiting the dust channel  124  to the environment. The overall dust removing effect is, thus, enhanced. 
     With reference to  FIG. 4 , the dust channel  124  extends in a direction at an angle with the second plane P 2 . However, the dust channel  124  can extend in a direction perpendicular or parallel to the second plane P 2 . The extending direction of the dust channel  124  is preferably related to the moving direction of the air currents driven by the impeller  3  rotating in the clockwise direction. In the example shown in  FIG. 4 , the dust channel  124  extends in a direction at an angle with the second plane P 2  to reduce the resistance to the air currents that are driven by the impeller  3  to flow along an inner face of the sidewall  12  into the dust channel  124 , assuring smooth dust removal operation. 
     With reference to  FIGS. 2 and 3 , a cover  13  can be mounted to the sidewall  12  of the housing  1 . The cover  13  includes an opening  131  aligned with the air inlet  122 . The cover  13  covers the compartment  121  over the air inlet  122 , so that the air currents generated by the impeller  3  can enter the housing  1  via the opening  131  and the air inlet  122 , providing a pressure increasing effect to smoothly guide the air currents to exit the air outlet  123 . 
     With reference to  FIGS. 2 and 3 , the base  11  of the housing  1  can further include a plurality of auxiliary air inlets  111  aligned with the air inlet  122 . The air currents generated by the impeller  3  can also enter the housing  1  via the auxiliary air inlets  111 , increasing the air input. 
     With reference to  FIGS. 2 and 3 , a plurality of fins  14  can be formed in the air outlet  123 . The fins  14  can be directly formed in the air outlet  123  or integrated as a heat sink mounted to the air outlet  123 . Thus, when the housing  1  is coupled to the electronic product, the fins  14  can absorb the high heat generated by the heat source of the electronic product, providing further enhanced heat dissipating effect while the impeller  3  drives air currents through the air outlet  123 . 
     With reference to  FIG. 5 , a dust guiding pipe  15  can be attached to the dust channel  124  for guiding the dust removed from the housing  1  to a position away from the housing  1 , assuring the dust removing effect. 
       FIGS. 6-8  show a heat dissipating fan of a second embodiment according to the preferred teachings of the present invention. In this embodiment, the heat dissipating fan includes a housing  5 , a stator  6 , an impeller  7 , and a control element  8 . Although the housing  5  is preferably of blower type, the housing  5  can be of axial-flow type. The stator  6  is mounted in the housing  5 . The impeller  7  is rotatably coupled to the stator  6 . The control element  8  controls the impeller  7  to rotate in the clockwise or counterclockwise direction. 
     Specifically, the housing  5  includes a base  51  and a lateral wall  52 . The base  51  and the lateral wall  52  together define a compartment  521 . The lateral wall  52  includes an air inlet  522  and an air outlet  523  both in communication with the compartment  521 . The air inlet  522  can act as a dust channel. A plurality of fins  54  is mounted in the air outlet  523 . 
     The stator  6  is mounted to the base  51  of the housing  5  and includes a coil unit  61  and a shaft seat  62 . The coil unit  61  is mounted around or integrally formed with an outer periphery of the shaft seat  62 . Alternatively, instead of being mounted to the base  51 , the shaft seat  62  of the stator  6  may integrally formed on the base  51 . 
     The impeller  7  is mounted in the compartment  521  of the housing  5  and is preferably of an axial-flow type. The impeller  7  includes a hub  71  rotatably coupled to the shaft seat  62  of the stator  6  and a plurality of blades  72  coupled to an outer periphery of the hub  71 . 
     The control element  8  includes a driving circuit  81  and a rotating direction control circuit  82 . The driving circuit  81  is electrically connected to the coil unit  61  of the stator  6 . The rotating direction control circuit  82  is electrically connected to the driving circuit  81 . The driving circuit  81  and the rotating direction control circuit  82  can be packaged in the same integrated circuit. 
     In use of the heat dissipating fan of the second embodiment according to the preferred teachings of the present invention, the rotating direction control circuit  82  can send a rotating direction control signal to the driving circuit  81  to drive the impeller  7  to rotate in a direction (such as the counterclockwise direction). Ambient air currents are drawn in via the air inlet  522  and then exit the air outlet  523  to the heat source of the electronic product for heat dissipating purposes ( FIGS. 6 and 7 ). Furthermore, the rotating direction control circuit  82  can send another rotating direction control signal to the driving circuit  81  to drive the impeller  7  to rotate in a reverse direction (such as the clockwise direction). Due to the characteristics of the blades  72  of the axial-flow type impeller  7 , the flowing direction of the air currents in the housing  5  driven by the impeller  7  rotating in the clockwise direction is opposite to that of the air currents driven by the impeller  7  rotating in the counterclockwise direction. Thus, the dust is less likely to accumulate in the housing  5 . Rather, the dust is removed outside of the housing  5  via the air inlet  522  acting as a dust channel. Thus, the dust accumulated in the housing  5  can be expelled to the environment ( FIGS. 6 and 8 ). 
     By controlling the impeller  7  to rotate in a reverse direction with the rotating direction control circuit  82  via the driving circuit  81 , the heat dissipating fan of the second embodiment according to the preferred teachings of the present invention can automatically remove dust to avoid adverse affect to the overall heat dissipating effect resulting from accumulation of the dust in the housing  5  while providing the original heat dissipating function. Furthermore, the air inlet  522  of the housing  5  can be utilized as the dust channel without the need of forming a dust channel  124  in the sidewall  12  of the housing  1 . The structure of the heat dissipating fan is, thus, simplified. 
     The additional features of the first embodiment can be utilized in the second embodiment according to the teachings of the present invention, details of which are not described to avoid redundancy. 
     In conclusion, the heat dissipating fans according to the teachings of the present invention can control the impeller  3 ,  7  by the rotating direction control circuit  42 ,  82  of the control element  4 ,  8  via the driving circuit  41 ,  81  to rotate in a reverse direction cooperating with the dust channel  124  (or the air inlet  522  of the second embodiment), allowing automatic dust removal operation to effectively remove the dust accumulated in the housing  1 ,  5  and, thus, providing convenient dust removing operation. Since the dust can be removed automatically, the dust is less likely to accumulate in the housing  1 ,  5  to an unexpected amount, effectively maintaining the air input and air output and enhancing the heat dissipating effect. 
     Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.