초록 ▼

The dynamic pressure bearing device is structured such that the pores of porous material as they are are disposed in the surfaces thereof forming the negative pressure cancel portions 15b and a lubricating fluid is supplied to the negative pressure generating areas thereof through the pores of the n

The dynamic pressure bearing device is structured such that the pores of porous material as they are are disposed in the surfaces thereof forming the negative pressure cancel portions 15b and a lubricating fluid is supplied to the negative pressure generating areas thereof through the pores of the negative pressure cancel portions 15b, whereby, even if recess-shaped grooves forming the negative pressure cancel portions 15b are formed shallow in depth and wide in width, or even if such grooves themselves are not formed at all, the dynamic pressure bearing device is able to fulfill its negative pressure cancel function in a sufficient manner. This makes it possible to eliminate the need for provision of the conventional recess-shaped grooves which are formed deep and narrow, thereby eliminating the need to execute an expensive operation such as a cutting operation or the like, so that the negative pressure cancel portions 15b can be formed at a low cost by inexpensive means such as by molding or the like.

대표청구항 ▼

[ What is claimed is:] [1.]1. A dynamic pressure bearing device comprising:a shaft member;a bearing member disposed so as to be relatively rotated with respect to said shaft member;a dynamic pressure generating section formed in at least one of said shaft member and bearing member, said dynamic pres

[ What is claimed is:] [1.]1. A dynamic pressure bearing device comprising:a shaft member;a bearing member disposed so as to be relatively rotated with respect to said shaft member;a dynamic pressure generating section formed in at least one of said shaft member and bearing member, said dynamic pressure generating section including:a plurality of dynamic pressure generating portions respectively arranged intermittently along the peripheral direction of one of said shaft member and bearing member;a projecting surface for pressurizing a lubricating fluid, said projecting surface projects in the radial direction of one of said shaft member and bearing member toward the other; anda plurality of negative pressure cancel portions for canceling negative pressures generated together with the dynamic pressures that are generated by said plurality of dynamic pressure generating portions, said each negative pressure cancel portion interposed between the mutually adjoining ones of said plurality of dynamic pressure generating portions and, said negative pressure cancel portions being respectively formed of porous material and being structured in such a manner that a large number of pores of said porous material for supplying/absorbing said lubricating fluid are exposed to the surfaces of said negative pressure cancel portions.