Fluid Bearing Device

Abstract

Disclosed is a fluid bearing device in which a high adhesive strength is ensured in fixing another member by adhesion to a resin housing. A bearing sleeve is secured in position inside the resin housing, and a shaft member is radially supported in a non-contact fashion by a dynamic pressure action of lubricant generated in a radial bearing clearance between the shaft member and the bearing sleeve. A metal bracket for mounting the stator coil of a motor is fixed by adhesion to the outer periphery of the housing, in which the adhesion portion of the outer periphery of the housing to be fixed to the bracket is roughened, setting the surface roughness to 0.5 μmRa to 2.0 μmRa.

1 . A fluid bearing device comprising: a housing; a bearing sleeve secured in position inside the housing; a shaft member adapted to rotate relative to the bearing sleeve; and a radial bearing portion supporting the shaft member radially in a non-contact fashion with an oil film formed in a radial bearing clearance between an inner peripheral surface of the bearing sleeve and an outer peripheral surface of the shaft member, with another member being fixed by adhesion to the housing, 
 wherein at least the housing is formed of resin, and wherein, of the housing and the other member, an adhesion portion of the one formed of resin has a surface roughness of 0.5 μmRa or more.    
   
   
       2 . A fluid bearing device according to  claim 1 , wherein the adhesion portion has a surface roughness of 2.0 μmRa or less.  
   
   
       3 . A fluid bearing device according to  claim 1 , wherein the other member fixed to the housing by adhesion is a bracket for mounting a stator coil of a motor.  
   
   
       4 . A fluid bearing device according to  claim 1 , wherein the other member fixed to the housing by adhesion is a sealing member for sealing up an opening of the housing.  
   
   
       5 . A fluid bearing device according to  claim 1 , wherein the other member fixed to the housing by adhesion is a thrust bush closing a bottom portion of the housing.  
   
   
       6 . A fluid bearing device according to  claim 1 , wherein the other member fixed to the housing by adhesion is the bearing sleeve.  
   
   
       7 . A motor comprising a fluid bearing device as claimed in  claim 1;  a stator coil; and a rotor magnet.  
   
   
       8 . A fluid bearing device according to  claim 2 , wherein the other member fixed to the housing by adhesion is a bracket for mounting a stator coil of a motor.  
   
   
       9 . A fluid bearing device according to  claim 2 , wherein the other member fixed to the housing by adhesion is a sealing member for sealing up an opening of the housing.  
   
   
       10 . A fluid bearing device according to  claim 2 , wherein the other member fixed to the housing by adhesion is a thrust bush closing a bottom portion of the housing.  
   
   
       11 . A fluid bearing device according to  claim 2 , wherein the other member fixed to the housing by adhesion is the bearing sleeve.  
   
   
       12 . A motor comprising a fluid bearing device as claimed in  claim 2;  a stator coil; and a rotor magnet.  
   
   
       13 . A motor comprising a fluid bearing device as claimed in  claim 3;  a stator coil; and a rotor magnet.  
   
   
       14 . A motor comprising a fluid bearing device as claimed in  claim 4;  a stator coil; and a rotor magnet.  
   
   
       15 . A motor comprising a fluid bearing device as claimed in  claim 5;  a stator coil; and a rotor magnet.  
   
   
       16 . A motor comprising a fluid bearing device as claimed in  claim 6;  a stator coil; and a rotor magnet.  
   
   
       17 . A motor comprising a fluid bearing device as claimed in  claim 8;  a stator coil; and a rotor magnet.  
   
   
       18 . A motor comprising a fluid bearing device as claimed in  claim 9;  a stator coil; and a rotor magnet.  
   
   
       19 . A motor comprising a fluid bearing device as claimed in  claim 10;  a stator coil; and a rotor magnet.  
   
   
       20 . A motor comprising a fluid bearing device as claimed in  claim 11;  a stator coil; and a rotor magnet.