Fluid pump having bearing hold

Abstract

A fluid pump includes a stationary part. A rotator is rotatable around the inner circumferential periphery of the stationary part. One of the stationary part and the rotator includes at least one coil that generates magnetic force between the stationary part and the rotator for rotating the rotator when being supplied with electricity. A pump portion is provided to one axial end of the rotation axis of the rotator. A cover covers the other axial end of the rotation axis of the rotator and the stationary part. The cover defines an outlet passage through which fluid is discharged from the pump portion. The cover has a bearing hole that rotatably supports the other axial end of the rotation axis. The bearing hole has a closed bottom. The cover has a communication passage that communicates the outlet passage with the bearing hole.

1 . A fluid pump comprising: 
 a stationary part that has an inner circumferential periphery;    a rotator that is rotatable around the inner circumferential periphery, the rotator having a rotation axis,    wherein one of the stationary part and the rotator includes at least one coil,    the at least one coil generates magnetic force between the stationary part and the rotator for rotating the rotator when being supplied with electricity,    the fluid pump further comprising:    a pump portion that is provided to one axial end of the rotation axis of the rotator, the rotator being adapted to rotating the pump portion for pumping fluid; and    a cover that covers an other axial end of the rotation axis of the rotator, the cover covering the stationary part on a side of the other axial end of the rotation axis, the cover defining an outlet passage through which fluid is discharged from the pump portion,    wherein the cover has a bearing hole that rotatably supports the other axial end of the rotation axis,    the bearing hole has a closed bottom, and    the cover has a communication passage that communicates the outlet passage with the bearing hole.    
   
   
       2 . The fluid pump according to  claim 1 , 
 wherein the at least one coil includes a plurality of coils,    the stationary part includes a plurality of teeth, which are circumferentially arranged,    each of the plurality of coils is formed by concentrically winding a wire around an outer circumferential periphery of each of the plurality of teeth,    the plurality of coils circumferentially generates magnetic poles in inner circumferential peripheries of the plurality of teeth when being supplied with electricity,    the magnetic poles are switched by controlling electricity supplied to the plurality of coils,    the rotator has an outer circumferential periphery that is opposed to the inner circumferential peripheries of the plurality of teeth, and    the outer circumferential periphery of the rotator defines magnetic poles different from each other with respect to a rotative direction of the rotator.    
   
   
       3 . The fluid pump according to  claim 1 , 
 wherein the cover is formed of resin,    the cover directly supports the rotation axis, and    the rotation axis is rotatable with respect to the cover.    
   
   
       4 . The fluid pump according to  claim 1 , further comprising: 
 a metallic bearing that is a component separate from the cover,    wherein the cover is formed of resin,    the metallic bearing is press-inserted into the bearing hole, and    the metallic bearing rotatably supports the rotation axis.    
   
   
       5 . The fluid pump according to  claim 1 , wherein the cover is integrally formed of resin.  
   
   
       6 . The fluid pump according to  claim 1 , wherein the outlet passage has an outlet port that is eccentric with respect to the bearing hole.  
   
   
       7 . The fluid pump according to  claim 6 , 
 wherein the bearing hole and the outlet passage overlap, and    the bearing hole communicates with the outlet passage.    
   
   
       8 . The fluid pump according to  claim 1 , 
 wherein the bearing hole substantially axially extends to an closed axial end in the cover, and    the closed axial end blocks the bearing hole with respect to an axial direction of the bearing hole.    
   
   
       9 . A fluid pump comprising: 
 a stationary part that has an inner circumferential periphery;    a rotator that is rotatable around the inner circumferential periphery, the rotator having a rotation axis,    wherein one of the stationary part and the rotator includes at least one coil,    the at least one coil generates magnetic force between the stationary part and the rotator for rotating the rotator when being supplied with electricity,    the fluid pump further comprising:    a pump portion that is provided to one axial end of the rotation axis of the rotator, the rotator being adapted to rotating the pump portion for pumping fluid; and    a cover that covers an other axial end of the rotation axis of the rotator, the cover covering the stationary part on a side of the other axial end of the rotation axis, the cover defining an outlet passage through which fluid is discharged from the pump portion,    wherein the cover has a bearing hole that rotatably supports the other axial end of the rotation axis,    the bearing hole substantially axially extends to a closed axial end in the cover,    the closed axial end blocks the bearing hole with respect to an axial direction of the bearing hole, and    the cover has a communication passage that communicates the outlet passage with the bearing hole.    
   
   
       10 . The fluid pump according to  claim 9 , wherein the communication passage is located on a side of the bearing hole with respect to the closed axial end.