Liquid dynamic pressure bearing and spindle motor, hard-disk driving unit, and scanner motor using the bearing
AssigneeSeiko Instruments Inc.
InventorTadao Iwaki
Life of this patent
Estimating the term…
Abstract
A liquid dynamic pressure bearing has bearing portions provided at opposite ends of a rotor shaft. The bearing portions are spaced from the rotor shaft by a gap having only one opening portion to maintain lubrication oil therein. A capillary oil sealing portion is formed at the opening portion to prevent evaporation and leakage of oil. Inside the bearing portions, journal bearings are formed at the central axis of the rotor shaft to prevent precession of the rotor shaft. A driving mechanism for driving the rotor shaft and a load are formed between the bearing portions to provide a stable spindle motor resistant to external vibration.
Claims68
A liquid dynamic pressure bearing for supporting a rotor shaft, comprising:
- a pair of liquid dynamic pressure bearing portions disposable at opposite axial ends of a rotor shaft, each bearing portion having a bearing face for supporting a respective end of the rotor shaft with a gap defined between each of the bearing faces and the rotor shaft for maintaining therein a liquid used for lubrication, the gap having only one opening portion exposed to outside air;
- and
- a journal bearing disposable at a central axis of the rotor shaft at least at one side of the rotor shaft and defined by the rotor shaft and one of the liquid dynamic pressure bearing portions.
A spindle motor for supporting a rotor shaft with liquid dynamic pressure bearings, comprising:
- a rotor shaft disposed to undergo rotational movement;
- a pair of liquid dynamic pressure bearing portions disposed at opposite axial ends of the rotor shaft, each bearing portion having a bearing face for supporting a respective end of the rotor shaft with a gap defined between each of the bearing faces and the rotor shaft for maintaining therein a liquid used for lubrication, the gap having only one opening portion exposed to outside air;
- and
- a journal bearing formed at a central axis of the rotor shaft at least at one side of the rotor shaft and defined by the rotor shaft and one of the liquid dynamic pressure bearing portions.
A hard disk drive unit comprising:
- a rotor shaft disposed to undergo rotational movement;
- a magnetic disk media attached to the rotor shaft to undergo rotation therewith;
- a pair of liquid dynamic pressure bearing portions disposed at opposite axial ends of the rotor shaft, each bearing portion having a bearing face for supporting a respective end of the rotor shaft with a gap defined between each of the bearing faces and the rotor shaft for maintaining therein a liquid used for lubrication, the gap having only one opening portion exposed to outside air;
- and
- a journal bearing formed at a central axis of the rotor shaft at least at one side of one of the rotor shaft and defined by the rotor shaft and one of the liquid dynamic pressure bearing portions.
A scanner motor comprising:
- a rotor shaft disposed to undergo rotational movement;
- a polygon mirror attached to the rotor shaft to undergo rotation therewith;
- a pair of liquid dynamic pressure bearing portions disposed at opposite axial ends of the rotor shaft, each bearing portion having a bearing face for supporting a respective end of the rotor shaft, with a gap defined between each of the bearing faces and the rotor shaft for maintaining therein a liquid used for lubrication, the gap having only one opening portion exposed to outside air;
- and
- a journal bearing formed at a central axis of the rotor shaft at least at one side of the rotor shaft and defined by the rotor shaft and one of the liquid dynamic pressure bearing portions.
A liquid dynamic pressure bearing device comprising:
- a rotary member mounted to undergo rotation;
- and a dynamic pressure bearing rotatably supporting the rotary member, the dynamic pressure bearing having a bearing member disposed adjacent to at least one end of the rotary member and being spaced therefrom by a gap in which a lubricating liquid is maintained, the bearing member having a first bearing surface for supporting the rotary member in an axial direction thereof and a second bearing surface for supporting the rotary member in a radial direction thereof;
- wherein only one opening exposed to outside air is provided in the gap defined between the rotary member and the bearing member.
Dependencies are inferred from the claim text.