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US 2009/0022438 A1Published application
Bearing assembly, motor, and disk drive
AssigneeNidec Corporation
InventorTakehito TAMAOKA
Life of this patent
Estimating the term…
Abstract
A sleeve and a sleeve housing are bonded to each other with adhesive. A thrust dynamic pressure bearing portion is configured between a thrust plate attached to a distal end of a shaft and the lower end surface of the sleeve. An annular step portion having a smaller diameter is provided at the lower side of the sleeve housing, and the annular step portion meets the sleeve. An annular raised portion is provided between thrust dynamic pressure grooves on the lower end surface of the sleeve and the annular step portion. In this configuration, the surplus adhesive leaked from between the sleeve and the annular step portion can be blocked by the annular raised portion, thereby preventing the adhesive from flowing into the thrust dynamic pressure bearing portion.
Claims23
A bearing assembly using a hydrodynamic pressure, comprising:
- a shaft centered on a center axis;
- a hollow sleeve operable to receive the shaft therein and centered in the center axis, one of the shaft and the sleeve being rotatable about the center axis relative to the other;
- a thrust plate in the form of a substantially circular plate extending from a lower portion to outside in a radial direction perpendicular to or substantially perpendicular to the center axis, the thrust plate facing a lower end surface of the sleeve and being smaller in outer diameter than the lower end surface of the sleeve;
- and
- a sleeve housing arranged outside the sleeve and the thrust plate in the radial direction, wherein
- the sleeve housing includes:
- a hollow portion, approximately cylindrical, having an inner side surface to which an outer side surface of the sleeve is bonded with adhesive;
- and
- a step portion projecting radially inward from an inner side surface of the hollow portion and being in contact with the lower end surface of the sleeve, the sleeve is provided with a thrust surface and an adhesive stopping feature on its lower end surface, the thrust surface facing the thrust plate, the adhesive stopping feature arranged between the thrust surface and the outer side surface of the sleeve, and
- a first communicating groove and a second communicating groove are provided between the sleeve and the sleeve housing, the first communicating groove extending in the radial direction between the lower end surface of the sleeve and the step portion, the second communicating groove axially extending between the outer side surface of the sleeve and the hollow portion of the sleeve housing, the first communicating groove being in communication with the second communicating groove.
7 more elements
A bearing assembly comprising:
- a shaft and a hollow sleeve receiving the shaft therein, one of the shaft and the sleeve being rotatable about a center axis relative to the other;
- a thrust plate extending from a lower portion of the shaft outward in a radial direction perpendicular to or substantially perpendicular to the center axis, facing a lower end surface of the sleeve, and being smaller in outer diameter than the lower end surface;
- and
- a sleeve housing arranged outside the sleeve and the thrust plate, and including a hollow portion, which has an inner side surface bonded to an outer side surface of the sleeve with adhesive, and a step portion which projects radially inward from the inner side surface of the hollow portion and is in contact with a radially outer portion of the lower end surface of the sleeve, wherein
- the sleeve is provided, on the lower end surface, with a thrust surface facing the thrust plate,
- the step portion of the sleeve housing is provided with an adhesive stopping feature facing the lower end surface of the sleeve,
- a first communicating groove and a second communicating groove are provided between the sleeve and the sleeve housing, the first communicating groove radially extending between the lower end surface of the sleeve and the step portion of the sleeve housing, the second communicating groove axially extending between the outer side surface of the sleeve and the inner side surface of the hollow portion of the sleeve housing, the first communicating groove being in communication with the second communicating groove.
4 more elements
A bearing assembly comprising:
- a shaft and a hollow sleeve receiving the shaft therein, one of the shaft and the sleeve being rotatable about a center axis relative to the other;
- a thrust plate extending from a lower portion of the shaft outward in a radial direction perpendicular to or substantially perpendicular to the center axis, facing a lower end surface of the sleeve, and being smaller in outer diameter than the lower end surface;
- and
- a sleeve housing arranged outside the sleeve and the thrust plate, and including a hollow portion, which has an inner side surface bonded to an outer side surface of the sleeve with adhesive, and a step portion which projects radially inward from the inner side surface of the hollow portion and faces an outer periphery of the lower end surface of the sleeve with a gap therebetween, wherein
- the sleeve is provided, on the lower end surface, with a thrust surface facing the thrust plate,
- one of the lower end surface of the sleeve and a top surface of the step portion of the sleeve housing is provided with an adhesive stopping feature in the form of a raised portion or a recessed portion,
- a first communicating groove and a second communicating groove are provided between the sleeve and the sleeve housing, the first communicating groove radially extending between the lower end surface of the sleeve and the step portion of the sleeve housing, the second communicating groove axially extending between the outer side surface of the sleeve and the inner side surface of the hollow portion of the sleeve housing, the first communicating groove being in communication with the second communicating groove.
4 more elements
Dependencies are inferred from the claim text.