Bearing unit and rotary drive using the same

Abstract

A bearing unit for rotatably supporting a shaft comprises a seamless holding member with a gap allowing a shaft to run through and extend to the outside, a bearing arranged in the inside of the holding member to rotatably support the shaft so as to make it radially revolvable, an anti-shaft-release member fitted to the shaft so as to abut the bearing in order to prevent the shaft from slipping away in the thrusting direction and a space-forming member arranged in the inside of the holding member so as to secure a space around the anti-shaft-release member. A bearing unit may further comprise an lubricating oil seal member and the space-forming member may be used to form a passage way for lubricating oil to prevent lubricating oil from leaking.

1 . A bearing unit for rotatably supporting a shaft, comprising: 
 a seamless holding member with a gap allowing a shaft to run through and extend to the outside;    a bearing arranged in the inside of the holding member to support the shaft so as to make it radially revolvable;    an anti-shaft-release member fitted to the shaft so as to abut the bearing in order to prevent the shaft from slipping away in the thrusting direction; and    a space-forming member arranged in the inside of the holding member so as to secure a space around the anti-shaft-release member.    
   
   
       2 . The bearing unit according to  claim 1 , wherein the anti-shaft-release member and the shaft are formed integrally with each other.  
   
   
       3 . The bearing unit according to  claim 1 , wherein the holding member is made of a polymeric material and the gap is defined by the holding member and the shaft at the position where the shaft extends from the holding member.  
   
   
       4 . The bearing unit according to  claim 1 , wherein the space-forming member is made of a polymeric material and operates as a thrust bearing for rotatably supporting the shaft at an end of the latter in the thrusting direction and the end of the shaft is made to show a spherical profile while the thrust bearing is a pivot bearing.  
   
   
       5 . The bearing unit according to  claim 1 , further including dynamic pressure generating grooves on the outer peripheral surface of the shaft or on the inner peripheral surface of the bearing.  
   
   
       6 . The bearing unit according to  claim 2 , wherein the surface of the anti-shaft-release member or the surface of the space-forming member arranged vis-à-vis the anti-shaft-release member is provided with dynamic pressure generating grooves.  
   
   
       7 . The bearing unit according to  claim 1 , wherein the shaft and the space-forming member are made of an electrically conductive material and the space-forming member is exposed to the outside through the holding member.  
   
   
       8 . A rotary drive including a bearing unit for rotataby supporting a shaft, comprising: 
 a seamless holding member with a gap allowing a shaft to run through and extend to the outside;    a bearing arranged in the inside of the holding member to support the shaft so as to make it radially revolvable;    an anti-shaft-release member fitted to the shaft so as to abut the bearing in order to prevent the shaft from slipping away in the thrusting direction; and    a space-forming member arranged in the inside of the holding member so as to secure a space around the anti-shaft-release member.    
   
   
       9 - 29 . (canceled)