Hydrodynamic type bearing and hydrodynamic type bearing unit
AssigneeNtn Corporation
InventorsNatsuhiko Mori, Kazuo Okamura
Life of this patent
Estimating the term…
Abstract
A thrust bearing section (14) is constituted by one bearing end face (11f1) of a hydrodynamic type oil-impregnated sintered bearing (11) and a flange portion (13a) provided on a rotating shaft (13). The squareness between the bearing end face (11f1) and the bearing inner periphery (11h) is set within 3 μm, and the squareness between the flange portion (13a) and the outer periphery of the rotating shaft (13) is set within 2 μm. The bearing bore diameter d and the bearing length L of the hydrodynamic type oil-impregnated sintered bearing are set as L≦1.2 d, and a radial bearing surface (11b) is arranged at one place on the bearing inner periphery (11h).
Claims13
A hydrodynamic type oil-impregnated sintered bearing unit comprising a shaft and a hydrodynamic type oil-impregnated sintered bearing including a bearing body formed of sintered metal, said bearing body being provided with a radial bearing surface opposed to an outer periphery of said shaft via a bearing clearance and being impregnated with oil, said hydrodynamic type oil-impregnated sintered bearing supporting said shaft without contact by means of hydrodynamic action produced on said radial bearing surface in a relative rotation between said shaft and said bearing body, wherein:
- at least one bearing end face of said hydrodynamic type oil-impregnated sintered bearing and a flange portion provided on said shaft constitute a thrust bearing section;
- and
- a squareness between said one bearing end face and a bearing inner periphery and a squareness between said flange portion and the outer periphery of said shaft are controlled to a tolerance that said one bearing end face and said flange portion are kept out of uneven contact with each other in a relative rotation between said shaft and said bearing body.
A hydrodynamic type bearing having a radial bearing surface provided in an inner periphery of a bearing body, said radial bearing surface having a hydrodynamic pressure generating groove slanting against an axial direction, said radial bearing surface being opposed via a radial bearing clearance to an outer periphery of a shaft member to be supported, wherein
- a thrust bearing surface having a hydrodynamic pressure generating groove is formed on at least one end face of said bearing body, simultaneously with said radial bearing surface, wherein both of said radial bearing surface and said thrust bearing surface are pressed surfaces formed bv a forming die having a shape corresponding to the bearing surface of a finished product.
Dependencies are inferred from the claim text.