Hydrodynamic bearing device
OwnerTsutomu Hamada, Takafumi Asada +1inventors
InventorsTsutomu Hamada, Takafumi Asada, Hideaki Ohno
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Abstract
A hydrodynamic bearing device is provided for use with a spindle motor. The hydrodynamic bearing device has a sleeve made of a sintered metal that is obtained by sintering a sintering material that is iron, an iron alloy, copper, a copper alloy or a mixture thereof. This sintered metal has independent pores, which do not communicate with each other, by selecting conditions for forming a desired sintered body within a predetermined range. The conditions includes a grain size of powdered metal of a material for the sintered metal, a molding pressure when the molded body is formed, sintering temperature and sintering period in the sintering step.
Claims4
A method for manufacturing a hydrodynamic bearing device comprising:
- forming a sleeve by sintering a sintering material containing at least one selected from a group containing iron, an iron alloy, copper and a copper alloy and by selecting at least one of sintered body forming conditions including a molding pressure when the sintered body is molded, sintering temperature and sintering period that are sintering conditions, and an average grain size of metal grains of the sintering material such that the sleeve has pores in which neighboring pores are independent from each other, and a bearing bore with a dynamic pressure generating groove formed on an inner surface of the bearing bore, with the pores having smaller diameters than each of a width and a height of a crest portion of the radial dynamic pressure generating groove;
- inserting a shaft in the bearing bore of the sleeve in a relatively rotatable manner;
- providing a thrust member that is opposed to the thrust flange, with providing a dynamic pressure generating groove on an opposed surface formed on at least one of the thrust flange and the thrust member;
- and
- filling working fluid in a gap between the shaft and the bearing bore, and between the thrust flange and the thrust member.
A method for manufacturing a hydrodynamic bearing device comprising:
- forming a sleeve by sintering a sintering material containing at least one selected from a group containing iron, an iron alloy, copper and a copper alloy and by selecting at least one of sintered body forming conditions including a molding pressure when the sintered body is molded, sintering temperature and sintering period that are sintering conditions, and an average grain size of metal grains of the sintering material such that the sleeve has pores in which neighboring pores are independent from each other, and a bearing bore with a radial dynamic pressure generating groove formed on an inner surface of the bearing bore, with the pores having smaller diameters than each of a width and a height of a crest portion of the radial dynamic pressure generating groove;
- inserting a shaft in the bearing bore of the sleeve in a relatively rotatable manner;
- providing a thrust member, with providing a dynamic pressure generating groove on an opposed surface formed on one of the end surface of the shaft and the thrust member;
- and
- filling working fluid in a gap between the shaft and the bearing bore, and between the end surface of the shaft and the thrust member.
Dependencies are inferred from the claim text.