Housing for fluid dynamic bearing device

Abstract

Provided is a housing for a resin fluid dynamic bearing device in which deterioration with time of a fixing force for another member is mitigated and which can maintain a high bearing performance for a long period of time. The housing formed of a resin composition exhibiting a compression creep amount of 8% or less when a compressive pressure of 80 MPa is applied for 168 hours at an atmosphere temperature of 80° C., provides a sufficient fixing force for the another member fixed with a press-fitting force, for example, a bearing sleeve press-fitted into an inner periphery of the housing even after a long term use. Thus, there is no fear of fixing positions of the another member with respect to the housing being deviated and a high bearing performance is maintained for a long period of time.

1 . A housing for a fluid dynamic bearing device, to be fixed to another member with a press-fitting force, characterized in that: at least a portion of the housing for the fluid dynamic bearing device, held in contact with the another member with the press-fitting force is formed of a resin composition; and that the resin composition exhibits a compression creep amount of 8% or less when a compressive pressure of 80 MPa is applied thereto for 168 hours at an atmosphere temperature of 80° C. 
   
   
       2 . A housing for a fluid dynamic bearing device according to  claim 1 , wherein the resin composition has a volume resistivity of 10 7  Ω·cm or less. 
   
   
       3 . A housing for a fluid dynamic bearing device according to  claim 1 , wherein the resin composition contains polyphenylene sulfide (PPS) as a base resin. 
   
   
       4 . A fluid dynamic bearing device comprising: the housing for a fluid dynamic bearing device according to  claim 1 ; a bearing sleeve fixed to an inner periphery of the housing; and a shaft. 
   
   
       5 . A fluid dynamic bearing device comprising: the housing for a fluid dynamic bearing device according to  claim 2 ; a bearing sleeve fixed to an inner periphery of the housing; and a shaft. 
   
   
       6 . A fluid dynamic bearing device comprising: the housing for a fluid dynamic bearing device according to  claim 3 ; a bearing sleeve fixed to an inner periphery of the housing; and a shaft. 
   
   
       7 . A motor comprising: the fluid dynamic bearing device according to  claim 4 ; a rotor magnet; and a stator coil. 
   
   
       8 . A motor comprising: the fluid dynamic bearing device according to  claim 5 ; a rotor magnet; and a stator coil. 
   
   
       9 . A motor comprising: the fluid dynamic bearing device according to  claim 6 ; a rotor magnet; and a stator coil.