Dynamic pressure bearing made of porous material

摘要

The invention provides a dynamic pressure bearing capable of generating enough dynamic pressure even with use of a porous material. Dynamic pressure grooves 1 at an inner circumferential surface of a sleeve 3 made of porous material are formed by rolling process. Voids of the porous material at a surface of the dynamic pressure grooves 1 are crushed by this rolling process, making the dynamic pressure grooves 1 airtight. Further, the inner circumferential surface at which the dynamic pressure grooves 1 are formed is subjected to sizing process, by which a bearing surface 2 of the sleeve 3 is crushed so that substantially no voids are present.