Miniature pump for liquid cooling system

Abstract

A miniature pump in accordance with the present invention comprises a pump casing ( 10 ) and a liquid circulating unit ( 20 ) received in the pump casing. The pump casing comprises a hollow main body ( 14 ) transversely forming a spacing plate ( 126 ) and a partition wall ( 144 ) spaced from the spacing plate. The liquid circulating unit comprises a shaft ( 25 ) mounted between the partition wall and the spacing plate, a bearing ( 27 ) rotatably mounted the shaft, an impeller ( 26 ) attached to the bearing, a first pair of spaced magnetic spacers ( 21,22 ) surrounding an upper portion of the shaft and positioned above the bearing, and a second pair of spaced magnetic spacers ( 23, 24 ) surrounding a lower portion of the shaft and positioned below the bearing. The two pairs of magnetic spacers properly suspend the impeller in a stable position in an axial direction of the pump when the impeller rotates.

1 . A miniature pump for use with a liquid cooling system, comprising: 
 a pump casing comprising a hollow main body transversely forming a spacing plate and a partition wall below and spaced from the spacing plate; and    a liquid circulating unit received in a receiving space between the spacing plate and the partition wall for circulating liquid in the liquid cooling system, the liquid circulating unit comprising a shaft fixedly mounted between the partition wall and the spacing plate, a bearing mounted to the shaft and rotatable in respect thereto, an impeller attached to the bearing to rotate therewith, a first pair of spaced magnetic spacers surrounding an upper portion of the shaft and positioned above the bearing, and a second pair of spaced magnetic spacers surrounding a lower portion of the shaft and positioned below the bearing; wherein the two pairs of magnetic spacers suspend the impeller in a stable position in an axial direction of the shaft when the impeller rotates so that the impeller is prevented from rubbing against the partition wall when the impeller rotates.    
   
   
       2 . The miniature pump as described in  claim 1 , wherein one of the first pair of magnetic spacers is received in the impeller, and the other one of the first pair of magnetic spacer is received in the spacing plate.  
   
   
       3 . The miniature pump as described in  claim 1 , wherein one of the second pair of magnetic spacers is received in the impeller, and the other one of the second pair of magnetic spacers is received in the partition wall.  
   
   
       4 . The miniature pump as described in  claim 1 , wherein each of the magnetic spacers has a north pole and an opposite south pole, the first pair of magnetic spacers have same poles at opposing surfaces thereof so that a repulsive force exists between the first magnetic spacers, and the second pair of magnets have same poles at opposing surfaces thereof so that a repulsive force exists between the second pair of magnetic spacers.  
   
   
       5 . The miniature pump as described in  claim 1 , wherein the spacing plate defines a through opening for allowing the liquid to enter the receiving space.  
   
   
       6 . The miniature pump as described in  claim 1 , wherein the partition wall forms a shaft support defining a center blind hole and a recess surrounding and communicating with the blind hole, an end of the shaft is received in the blind hole, and one of the second pair of magnetic spacers is received in the recess, and the spacing plate forms a cap and a protrusion having an inner space communicating with the cap, an opposite end the shaft is received in the protrusion, and one of the first pair of magnetic spacers is received in the cap.  
   
   
       7 . The miniature pump as described in  claim 6 , wherein the impeller comprises a center hollow post having a receiving room and a plurality of blades, the other one of the first pair of magnetic spacers is received in an upper portion of the receiving room, and the other one of the second pair of magnetic spacers is received in a lower portion of the receiving room.  
   
   
       8 . The miniature pump as described in  claim 7 , wherein the blades of the impeller comprises alternating first and second blades, the first blades extend from the center post to an outer edge portion of impeller and the second blades are formed at the outer edge portion of the impeller.  
   
   
       9 . The miniature pump as described in  claim 1 , further comprising a motor driving unit received in the pump casing below the partition wall for driving the impeller of the liquid circulating unit to rotate.  
   
   
       10 . The miniature pump as described in  claim 9 , wherein the impeller carries a first permanent magnet, the motor driving unit comprises a motor having a rotor, and a second permanent magnet is attached to the rotor corresponding to the first permanent magnet.  
   
   
       11 . The miniature pump as described in  claim 10 , wherein the first permanent magnet is embedded in the impeller.  
   
   
       12 . The miniature pump as described in  claim 10 , wherein each of the first and second permanent magnets comprises a ring-shaped flat body, and an axial flux gap is created between the first and second permanent magnets.  
   
   
       13 . A liquid pump for use with a liquid cooling system, comprising: 
 a pump casing comprising a spacing plate having a first magnetic spacer and a partition wall having a second magnetic spacer both transversely formed therein to form an inner space between the spacing plate and the partition wall for receiving a magnetically levitated impeller therein, the impeller having a pair of third magnetic spacers, one of the third magnetic spacers of the impeller being received in an upper portion of the impeller and being opposite to the first magnetic spacer of the spacing plate, and the other one of the third magnetic spacers of the impeller being received in a lower portion of the impeller and being opposite to the second magnetic spacer of the partition wall; and    a motor driving unit positioned outside of the inner space to drive the impeller to rotate; wherein when the impeller is rotated by the motor, the impeller is suspended between the spacing plate and the partition wall and total axial force to the impeller is balanced.    
   
   
       14 . The liquid pump as described in  claim 13 , wherein each of the first, second and third magnetic spacers has a north pole and an opposite south pole, the first magnetic spacer and the one of the third magnetic spacers have same poles at opposing surfaces thereof so that a repulsive force exists therebetween, the second magnetic spacer and the other one of the third magnetic spacers have same poles at opposing surfaces thereof so that a repulsive force exists therebetween.  
   
   
       15 . The liquid pump as described in  claim 14 , wherein the impeller carries a first permanent magnet, the motor driving unit comprises a rotor and a second permanent magnet attached to the rotor for rotating therewith, and the second permanent magnet corresponds to the first permanent magnet with a flux gap formed therebetween.  
   
   
       16 . The liquid pump as described in  claim 14 , wherein the pump casing comprises a hollow main body, a top cover hermetically attached to a top end of the main body, and a bottom cover attached to a bottom end of the main body to form a receiving space between the partition wall and the bottom cover to receive the motor driving unit therein.  
   
   
       17 . A liquid pump, comprising: 
 a pump casing comprising a liquid inlet, a liquid outlet below the liquid inlet and a receiving space therein;    an impeller rotatably mounted in the receiving space, wherein when the impeller rotates liquid is driven to flow into the pump via the liquid inlet and out of the pump via the liquid outlet, a magnet attached to the impeller;    a first pair of magnetic spacers mounted respectively on the impeller and the pump casing, the first pair of magnets being so positioned that a repulsive force exists therebetween, the repulsive force counteracting a downward force acting on the impeller during rotation of the impeller to drive the liquid to flow; and    a motor driving unit interacting with the magnet attached on the impeller to drive the impeller to rotate.    
   
   
       18 . The liquid pump as described in  claim 17 , further comprising a second pair of magnetic spacers respectively mounted on the impeller and the pump casing, the second pair of magnetic spacers being so positioned that a repulsive force exists therebetween, the second pair of magnetic spacers being located above the first pair of magnetic spacers.  
   
   
       19 . The liquid pump as described in  claim 18 , further comprising a shaft, the impeller rotating around the shaft, the first pair of magnetic spacers surrounding a lower portion of the shaft and located below the impeller, and the second pair of magnetic spacers surrounding an upper portion of the shaft and located above the impeller.  
   
   
       20 . The liquid pump as described in  claim 19 , wherein the motor driving unit is located below the first pair of magnetic spacers.