US 6,485,179 B1Granted

Dynamic pressure bearing

AssigneeKoyo Seiko Co., Ltd.

InventorsTakeshi Takahashi, Yasuo Takamura, Daiji Hiraoka

Life of this patent

Estimating the term…

Loading patent…

Abstract

A dynamic pressure bearing is provided in which leakage of liquid lubricant due to precession of a housing can be prevented from occurring. In the dynamic pressure bearing, the inner diameter of a tapered inner peripheral face 20 of the housing 1 which constitutes a capillary sealing portion 23 is gradually increased as moving from an opening 17 toward the inner area in the axial direction. When the housing 1 is rotated, therefore, a centrifugal force applied on liquid lubricant existing on the tapered inner peripheral face 20 acts in the direction along which the liquid lubricant is pushed toward the inner area, as indicated by an arrow 19. Consequently, the centrifugal force which is due to precession of the housing 1, and which pushes the liquid lubricant 15 toward the outside as indicated by an arrow 29 can be cancelled by the force acting in the direction toward the inner area, with the result that leakage of the liquid lubricant due to precession of the housing 1 can be prevented from occurring.

Claims28

Dependent claims

A dynamic pressure bearing assembly, comprising:

a housing defining a bore and a bore opening having a bore opening diameter;
a shaft disposed in said bore extending through said opening and defining a shaft axis, said shaft having a first shaft diameter portion having a first shaft diameter, a second shaft diameter portion having a second shaft diameter less than said first shaft diameter, and a tapered shaft portion between said first shaft diameter portion and said second shaft diameter portion and defining a shaft inclination angle with respect to said shaft axis;
said bore having a first bore diameter portion having a first bore diameter and opposing said first shaft diameter portion and defining a first gap region therebetween;
said bore having a second bore diameter portion having a second bore diameter greater than said first bore diameter and opposing said first shaft diameter portion and said tapered shaft portion to define:
a second gap region between said second bore diameter portion and said first shaft diameter portion;
and
a third gap region between said second bore diameter portion and said tapered shaft portion;
said bore having a tapered bore portion between said second diameter bore portion and said bore opening defining a bore inclination angle with respect to said shaft axis wherein said second bore diameter is greater than said bore opening diameter, and said tapered bore portion and said tapered shaft portion define a fourth gap region therebetween;
said first gap region having a first gap region radial width;
said second gap region having a second gap region radial width greater than said first gap region radial width;
said third gap region having an increasing third gap region radial width, increasing towards said bore opening, which is increasingly greater than said second gap region radial width;
and
said fourth gap region having an increasing fourth gap region radial width, increasing towards said bore opening, which is increasingly greater than a largest size of said increasing third gap region radial width;
wherein said second, third and fourth gap regions form a capillary seal.

11 more elements

A dynamic pressure bearing assembly, comprising:

a housing defining a bore opening having a bore opening diameter;
a shaft disposed in said bore extending through said opening and defining a shaft axis, said shaft having a first shaft diameter portion having a first shaft diameter, a second shaft diameter portion having a second shaft diameter less than said first shaft diameter, and a tapered shaft portion interconnecting said first shaft diameter portion and said second shaft diameter portion and defining a shaft inclination angle with respect to said shaft axis;
said bore having a first bore diameter portion having a first bore diameter and opposing said first shaft diameter portion and defining a first gap region therebetween;
said bore having a second bore diameter portion having a second bore diameter greater than said first bore diameter and opposing said first shaft diameter portion and said tapered shaft portion to define:
a second gap region between said second bore diameter portion and said first shaft diameter portion;
and
a third gap region between said second bore diameter portion and said tapered shaft portion;
said bore having a tapered bore portion extending from said second diameter bore portion to said bore opening defining a bore inclination angle with respect to said shaft axis wherein said second bore diameter is greater than said bore opening diameter, and said tapered bore portion and said tapered shaft portion define a fourth gap region therebetween;
said first gap region having a first gap region radial width;
said second gap region having a second gap region radial width greater than said first gap region radial width;
said third gap region having an increasing third gap region radial width, increasing towards said bore opening, which is increasingly greater than said second gap region radial width;
and
said fourth gap region having an increasing fourth gap region radial width, increasing towards said bore opening, which is increasingly greater than a largest size of said increasing third gap region radial width;
wherein said second, third and fourth gap regions form a capillary seal.

11 more elements

Dependencies are inferred from the claim text.