Rotating shaft conical fluid dynamic bearing
View Patent ↗A fluid dynamic bearing design is provided featuring a rotating shaft with at least one conical bearing formed integrally thereon. The shaft is disposed through a stationary sleeve, and a fluid separates the shaft and sleeve surfaces.
1. A fluid dynamic bearing system for a disk drive motor comprising:
a rotatable shaft;
a first conical bearing including a conical region formed integral with a first end of the shaft;
a second conical bearing including a cone affixed to a second end of the shaft;
a stationary sleeve disposed around the shaft;
a gap defined between an end surface of the shaft adjacent the second conical bearing and a facing surface of a counterplate supported from the sleeve; and
a common fluid disposed between the first conical bearing and the stationary sleeve, and the second conical bearing and the stationary sleeve.
2. A fluid dynamic bearing system as claimed in claim 1 further comprising a radial capillary seal adjacent an outer end of at least one of the first and second conical bearings.
3. The fluid dynamic bearing system according to claim 2 , wherein the radial capillary seal defines a fluid reservoir.
4. A fluid dynamic bearing system as claimed in claim 1 further comprising a vent and fill hole defined intermediate the first and second conical bearings.
5. A fluid dynamic bearing system as claimed in claim 4 wherein the vent comprises a radial bore extending from the central region of the shaft through the sleeve to the outer diameter of the sleeve.
6. A fluid dynamic bearing system as claimed in claim 1 further comprising one or more fluid return paths interior to the cone of the second conical bearing from a wider end of the cone toward a narrower end of the cone and the center region of the shaft.
7. The fluid dynamic bearing system of claim 1 further comprising an axially oriented fluid recirculation path extending from a vent to a radial capillary seal adjacent a wider end of the first conical bearing.
8. A fluid dynamic bearing system as claimed in claim 1 further comprising grooves defined on a surface of each of the first and second conical bearings, each of the grooves being asymmetric to pump the fluid toward an end of the shaft adjacent the second conical bearing.
9. A fluid dynamic bearing as claimed in claim 1 further comprising a radial capillary seal supported adjacent a wider end of the first conical bearing.
10. A fluid dynamic bearing system as claimed in claim 9 further comprising an axial bore extending from a plenum adjacent a wider end of the second conical bearing to a fluid reservoir region in the radial capillary seal to allow for recirculation of the common fluid over the first and second conical bearings.