Sintered bearing and method of manufacturing same
AssigneeNtn Corporation
InventorsTomonori Yamashita, Yoshinori Ito, Daisuke Takeda, Yuta Ohashi
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Abstract
Provided is a sintered bearing formed mainly of an iron structure (33) and a copper structure (31) which are formed of a partially diffusion-alloyed powder (11) of an iron powder (12) and a copper powder (13). The sintered bearing includes a copper structure (31d) formed of a granular elemental copper powder (13′) having a grain diameter of 45 μm or less, the ratio of the copper structure (31d) being 10 mass % or less. With this, a further increase in strength of the sintered bearing can be realized.
Claims18
A method for manufacturing a sintered bearing comprising:
- an iron structure and a first copper structure which are formed of partially diffusion-alloyed powder of iron powder and copper powder having a grain diameter smaller than that of the iron powder;
- and a second copper structure formed of granular elemental copper powder having a grain diameter of 45 μm or less, the sintered bearing having a radial crushing strength of 350 MPa or more, and a ratio of the second copper structure formed of the granular elemental copper powder being 10 mass % or less, the method comprising sintering the partially diffusion-alloyed powder at a sintering temperature of 900° C. or less to form the iron structure and the first copper structure, wherein the partially diffusion-alloyed powder contains 60 mass % or more of powder having a grain diameter of more than 106 μm, and the partially diffusion-alloyed powder has a maximum grain diameter of 150 μm or less, wherein the sintered bearing further comprises:
- a sintered compact;
- and a grease impregnated into the sintered compact, wherein the grease contains a thickener, and a base oil having a kinematic viscosity at 40° C. of 40 mm2/s or more and 60 mm2/s or less, and a kinematic viscosity at 100° C. of 5 mm2/s or more and 10 mm2/s or less according to a kinematic viscosity measurement based on JIS K 2283, and a concentration of the thickener in the grease is from 0.1 wt % to 3 wt %.
A method for manufacturing a sintered bearing comprising:
- an iron structure and a first copper structure which are formed of partially diffusion-alloyed powder of iron powder and copper powder having a grain diameter smaller than that of the iron powder;
- and a second copper structure formed of granular elemental copper powder having a grain diameter of 45 μm or less, the sintered bearing having a radial crushing strength of 350 MPa or more, and a ratio of the second copper structure formed of the granular elemental copper powder being 10 mass % or less, the method comprising sintering the partially diffusion-alloyed powder at a sintering temperature of 900° C. or less to form the iron structure and the first copper structure, wherein the partially diffusion-alloyed powder contains 60 mass % or more of powder having a grain diameter of more than 106 μm, and the partially diffusion-alloyed powder is free from powder having a grain diameter greater than 150 μm, wherein the sintered bearing further comprises:
- a sintered compact;
- and a grease impregnated into the sintered compact, wherein the grease contains a thickener, and a base oil having a kinematic viscosity at 40° C. of 40 mm2/s or more and 60 mm2/s or less, and a kinematic viscosity at 100° C. of 5 mm2/s or more and 10 mm2/s or less according to a kinematic viscosity measurement based on JIS K 2283, and a concentration of the thickener in the grease is from 0.1 wt % to 3 wt %.
Dependencies are inferred from the claim text.