Patent Publication Number: US-2010129235-A1

Title: Anti-vibration structure for cooling fan

Description:
FIELD OF THE INVENTION 
     The present invention relates to an anti-vibration structure, and more particularly to an anti-vibration structure for cooling fan, so that a cooling fan can operate with reduced noise and increased stability, and have prolonged service life. 
     BACKGROUND OF THE INVENTION 
     Presently, electronic elements on a mainboard of a computer, such as the central processing unit (CPU), have constantly increased operating speed, and therefore produce a relatively high amount of heat during the high-speed operation thereof. Under this condition, a heat-dissipating device is needed to quickly dissipate the high amount of heat produced by the electronic elements during the operation thereof, so as to ensure continuous normal operation and extended service life of the electronic elements. 
     Among different heat-dissipating devices, a cooling fan is able to quickly dissipate the heat absorbed by a radiating fin assembly to enable good air circulation and heat dissipation effect, and therefore becomes an indispensable part of a computer. 
       FIG. 1  shows a conventional cooling fan  1 , on which four fixing holes  11  are provided. When installing the cooling fan, a plurality of screws (not shown) is directly extended through the fixing holes  11  into the radiating fin assembly or a computer case (not shown), so as to firmly connect the cooling fan to the radiating fin assembly or the computer case. However, the above-described installing manner does not always ensure that the cooling fan  1  has been fully tightened in place by the screws. 
     When the cooling fan  1  is started to dissipate heat, it also produces vibration while rotating at high speed. The vibration is transferred to the radiating fin assembly or the computer case, causing the radiating fin assembly or the computer case to resonate. Therefore, after a long period of time of operation, the cooling fan  1  tends to become loosened from and strike against the radiating fin assembly or the computer case to produce noise. 
     In brief, the conventional cooling fan has the following disadvantages: (1) producing relatively large vibration; (2) producing bothersome noise due to resonance effect; (3) screws tightened thereto tending to loosen therefrom; (4) having shortened service life; and (5) having poor operating stability. 
     It is therefore tried by the inventor to develop an anti-vibration structure for cooling fan, so as to overcome the problems in the conventional cooling fan. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide an anti-vibration structure for cooling fan, so that a cooling fan can operate with reduced noise and increased stability. 
     Another object of the present invention is to provide an anti-vibration structure for cooling fan, so that a cooling fan can have prolonged service life. 
     To achieve the above and other objects, the anti-vibration structure for cooling fan according to the present invention includes a frame, a hub assembly, and an anti-vibration unit. The hub assembly is mounted in the frame. The frame includes at least a first, a second, a third, and a fourth sidewall. Any of the four sidewalls is connected at two opposite ends to respective one end of two adjacent sidewalls, and a radially inward recess is formed at each joint of any two adjacent sidewalls. The anti-vibration unit includes at least one main body, and the main body has one side being shaped for engaging with the recess. The anti-vibration unit absorbs vibration produced by an operating cooling fan to thereby reduce noise and allow the cooling fan to have increased operating stability and prolonged service life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
         FIG. 1  is an assembled perspective view of a conventional cooling fan; 
         FIG. 2  is an exploded perspective view showing an anti-vibration structure for cooling fan according to the present invention; and 
         FIG. 3  is an assembled view of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 2 and 3  that are exploded and assembled perspective views, respectively, showing an anti-vibration structure for cooling fan according to a preferred embodiment of the present invention. As shown, the anti-vibration structure for cooling fan includes a hub assembly  20 , a frame  30 , and an anti-vibration unit  40 . The hub assembly  20  is mounted in the frame  30 , and normally internally provided with electromagnetic driving elements, including a stator, a rotor, etc., for driving blades spaced along and radially outward extended from a circumferential face of the hub assembly  20 , so that the blades rotate to produce airflows to carry away heat produced by electronic elements. 
     The frame  30  includes at least a first sidewall  301 , a second sidewall  302 , a third sidewall  303 , and a fourth sidewall  304 . Any of the four sidewalls  301 - 304  is connected at two opposite ends to respective one end of two adjacent sidewalls. A radially inward recess  310  is formed at each joint of any two adjacent side walls, and at least one notch  320  is formed on each of the four sidewalls  301 - 304  to communicate with one adjacent recess  310 . 
     The anti-vibration unit  40  includes at least one main body  410 . The main body  410  has one face adapted to fitly engage with the recess  310  and thereby absorbs a vibration force produced by the cooling fan during the operation thereof. In the illustrated preferred embodiment of the present invention, there are four main bodies  410  included in the anti-vibration unit  40 . However, it is understood the number of the main bodies  410  is not limited to four. Preferably, the number of the main bodies  410  is the same as that of the recesses  310 . 
     The main bodies  410  of the anti-vibration unit  40  are engaged with the recesses  310  in a tight-fit relation. In other words, the main bodies  410  can be connected to the recesses  310  by supersonic welding and many other ways, such as clamping, rabbet joint, gluing, etc. Since vibration produced by the operating cooling fan is absorbed by the anti-vibration unit  40 , the cooling fan can have reduced noise, increased operating stability, and prolonged service life. 
     As can be seen from  FIGS. 2 and 3 , the frame  30  defines a first opening  331 , a second opening  332  opposite to the first opening  331 , and an air passage  333  communicating the first opening  331  with the second opening  332 . Airflows produced by the blades on the hub assembly  20  pass through the first opening  331  or the second opening  332  into the air passage  333  and then flow out of the frame  30  via the second opening  332  or the first opening  331 . 
     The main bodies  410  of the anti-vibration unit  40  are made of a rubber material or any other materials with vibration absorbing and cushioning ability. Each of the main bodies  410  is provided at two lateral ends with an outward projected extension  430  each. The extensions  430  correspond to the notches  320  formed on the sidewalls  301 - 304 . The extensions  430  each have a plurality of grooves  431  formed thereon. 
     Each of the main bodies  410  of the anti-vibration unit  40  is provided with a mounting hole  420  axially extended through the main body  410 . A plurality of fastening means, such as screws, can be separately extended through the mounting holes  420 . To assemble the cooling fan to a thermal module (not shown) or to an electronic element, simply apply a force to screw the fastening means into the mounting holes  420  to connect to the thermal module or the electronic element. 
     The following describes an example of using the anti-vibration structure for cooling fan according to the present invention. 
     When the hub assembly  20  brings the blades thereon to rotate, air is caused to flow through the first opening  331  into the air passage  333 , and then moves in a direction defined by the air passage  333  toward the second opening  332 , and finally flows to the thermal module via the second opening  332 , enabling heat exchange between the air and the thermal module to thereby achieve the purpose of quick heat dissipation. Meanwhile, vibration force produced by the hub assembly  20  when the same continuously rotates at high speed is absorbed by the main bodies  410  of the anti-vibration unit  40 . Thus, the anti-vibration unit  40  not only effectively reduces the vibration force produced by the cooling fan, but also reduces noise produced during the operation of the cooling fan. As a result, the cooling fan with the anti-vibration structure of the present invention can have increased operating stability and prolonged service life. 
     With the above arrangements, the anti-vibration structure for cooling fan according to the present invention has the following advantages: (1) capable of reducing the vibration produced by an operating cooling fan; (2) capable of reducing the noise produced by the operating cooling fan; (3) enabling the cooling fan to have prolonged service life; and (4) enabling the cooling fan to operate with high stability. 
     The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment 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.