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US 2014/0175924 A1Published application
Hydrodynamic bearing assembly and spindle motor having the same
AssigneeSamsung Electro-Mechanics Co., Ltd.
InventorSatoru SODEOKA
Life of this patent
Estimating the term…
Abstract
There is provided a hydrodynamic bearing assembly including a sleeve; and a shaft rotatably inserted into a shaft hole and constituting a bearing clearance, wherein at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft includes upper and lower radial dynamic pressure grooves having a herringbone pattern, and conditional expressions a+b>c+d and b−a>c−d>0 are satisfied.
Claims12
A hydrodynamic bearing assembly, comprising:
- a sleeve including a shaft hole formed therein;
- and
- a shaft rotatably inserted into the shaft hole, the shaft constituting, together with the sleeve, a bearing clearance filled with lubricating fluid,
- wherein at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft includes upper and lower radial dynamic pressure grooves having a herringbone pattern formed therein so as to pump the lubricating fluid filled in the bearing clearance, and
- when an axial direction distance from an upper end of the upper radial dynamic pressure groove to a highest pressure portion is ‘a’, an axial direction distance from a lower end of the upper radial dynamic pressure groove to the highest pressure portion is ‘b’, an axial direction distance from an upper end of the lower radial dynamic pressure groove to a highest pressure portion is ‘c’, and an axial direction distance from a lower end of the lower radial dynamic pressure groove to the highest pressure portion is ‘d’, conditional expressions a+b>c+d and b−a>c−d>0 are satisfied.
2 more elements
A spindle motor, comprising:
- a base member including an installation portion protruding in an axial direction;
- a sleeve housing fixedly installed on an inner surface of the installation portion;
- a sleeve inserted and fixeldy installed in the sleeve housing and including a shaft hole formed therein;
- a shaft rotatably inserted into the shaft hole;
- a flange member fixedly installed on the shaft to be disposed below the sleeve and rotating together with the shaft;
- and
- a rotor hub fixedly installed on an upper end portion of the shaft and including a protrusion wall portion protruding to form a liquid vapor interface together with an outer circumferential surface of the sleeve housing,
- wherein at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft includes upper and lower radial dynamic pressure grooves having a herringbone pattern formed therein so as to pump lubricating fluid filled in the bearing clearance, and
- when an axial direction distance from an upper end of the upper radial dynamic pressure groove to a highest pressure portion is ‘a’, an axial direction distance from a lower end of the upper radial dynamic pressure groove to the highest pressure portion is ‘b’, an axial direction distance from an upper end of the lower radial dynamic pressure groove to a highest pressure portion is ‘c’, and an axial direction distance from a lower end of the lower radial dynamic pressure groove to the highest pressure portion is ‘d’, conditional expressions a+b>c+d and b−a>c−d>0 are satisfied.
6 more elements
Dependencies are inferred from the claim text.