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US 7,411,762 B2Granted
Fluid dynamic pressure bearing including dynamic pressure generating grooves, and spindle motor and disc drive including the bearing
AssigneeNidec Corporation
InventorTakehito Tamaoka
Life of this patent
Estimating the term…
Abstract
In a fluid dynamic pressure bearing, upper herringbone grooves and lower herringbone grooves continuous with the upper herringbone grooves are formed on the inner peripheral surface of a sleeve by plastic deformation. In addition, an annular groove recessed radially inward is formed on the outer peripheral surface of the shaft in a location opposing the region where the upper herringbone grooves and the lower herringbone grooves adjoin.
Claims18
A fluid dynamic pressure bearing for a motor, comprising:
- a shaft;
- and
- a sleeve made of a porous material which is impregnated with a lubricating fluid, the sleeve and the shaft rotating relatively about a rotation central axis;
- wherein an upper radial dynamic pressure bearing and a lower radial dynamic pressure bearing are adjacently located around a location between said shaft and said sleeve, said upper and lower radial dynamic pressure bearings have a micro gap between said shaft and said sleeve, and said lubricating fluid is filled in said micro gap as a working fluid for inducing a dynamic pressure when said motor is rotating,
- wherein upper radial dynamic pressure-generating grooves are formed on an upper inner peripheral surface of said sleeve in said upper radial dynamic pressure bearing by plastic deformation, lower radial dynamic pressure-generating grooves are formed on a lower inner peripheral surface of said sleeve by plastic deformation, and said upper radial dynamic pressure-generating grooves are formed continuously to said lower radial dynamic pressure-generating grooves, and
- wherein an annular groove recessed radially inward is formed on an outer peripheral surface of said shaft at a place facing a borderline between said upper radial dynamic pressure-generating grooves and said lower radial dynamic pressure-generating grooves.
3 more elements
A fluid dynamic pressure bearing for a motor, comprising:
- a shaft;
- and
- a sleeve made of a porous material which is impregnated with a lubricating fluid, the sleeve and the shaft rotating relatively about a rotation central axis;
- wherein an upper radial dynamic pressure bearing and a lower radial dynamic pressure bearing are adjacently located around a location between said shaft and said sleeve, said upper and lower radial dynamic pressure bearings have a micro gap between said shaft and said sleeve, and said lubricating fluid is filled in said micro gap as a working fluid for inducing a dynamic pressure when said motor is rotating,
- wherein upper radial dynamic pressure-generating grooves are formed on an upper outer peripheral surface of said shaft in said upper radial dynamic pressure bearing by plastic deformation, lower radial dynamic pressure-generating grooves are formed on a lower outer peripheral surface of said shaft by plastic deformation, and said upper radial dynamic pressure-generating grooves are formed continuously to said lower radial dynamic pressure-generating grooves, and
- wherein an annular groove recessed radially outward is formed on an inner peripheral surface of said sleeve at a place facing a borderline between said upper radial dynamic pressure-generating grooves and said lower radial dynamic pressure-generating grooves.
3 more elements
Dependencies are inferred from the claim text.