Method And System For Withstanding A Shock Event For A Fluid Dynamic Bearing Motor

Abstract

A system, method and means is provided for withstanding mechanical shock for use with fluid dynamic bearings. A sealing system is provided that withstands 1000 G shock events. In an aspect, a grooved pumping seal employed between a thrust plate and a shield, a thrust plate having spiral grooves, a fluid recirculation passageway, and a reservoir creates an asymmetric pressure gradient. In an aspect, fluid is retained and air is purged utilizing an enlarged fluid reservoir, axial channels and an angled fill hole. In an aspect, a shaft is attached to a top cover supplying radial stiffness, and an enlarged single-sided thrust plate improves dynamic parallelism.

1 . A method for recirculating fluid, purging air, and withstanding shock for use with a fluid dynamic bearing motor comprising creating an asymmetric pressure gradient within an interfacial region of the fluid dynamic bearing motor, wherein the interfacial region is defined within an area including a journal bearing, a first fluid passageway, a second fluid passageway, and a reservoir, wherein the journal bearing, the first fluid passageway, and the second fluid passageway are connected for fluid recirculation, and are in fluid communication with the reservoir, and wherein:
 i.) the journal bearing is defined between an inner component and an outer component, the inner component and the outer component positioned for relative rotation;   ii.) the first fluid passageway is defined within the outer component;   iii.) the second fluid passageway is defined between the outer component and a radial member extending from the inner component; and   iv.) the reservoir is defined between a shield and the outer component, the shield connected to one of the inner component and the outer component.   
     
     
         2 . The method as in  claim 1 , wherein creating an asymmetric pressure gradient comprises employing grooves on at least one of a facing surface of the radial member and the outer component, to generate fluid pumping pressure to pump fluid from the second fluid passageway toward the inner component and into the journal bearing, when the inner component and the outer component are relatively rotating. 
     
     
         3 . The method as in  claim 1 , wherein creating an asymmetric pressure gradient comprises employing pumping grooves on a facing surface positioned at an outer diameter gap defined between the shield and an outer diameter of the radial member, to pump fluid from the outer diameter gap toward a recirculation plenum when the inner component and the outer component are relatively rotating, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         4 . The method as in  claim 1 , further comprising utilizing centrifugal force to act on fluid situated at an outer diameter gap defined between the shield and an outer diameter of the radial member, when the inner component and the outer component are relatively rotating. 
     
     
         5 . The method as in  claim 1 , wherein creating the asymmetric pressure gradient comprises creating a first pressure area within the reservoir, and creating a second pressure area within the journal bearing, wherein the first pressure area has a lower pressure than the second pressure area. 
     
     
         6 . The method as in  claim 5 , wherein creating the asymmetric pressure gradient further comprises creating a third pressure area at an axial end of the journal bearing, and creating a fourth pressure area at an apex of grooves formed on a facing surface of the journal bearing, wherein when the inner component and the outer component are relatively rotating, the third pressure area has a lower pressure than the fourth pressure area. 
     
     
         7 . The method as in  claim 1 , wherein creating the asymmetric pressure gradient comprises creating a lower pressure area and a lower flow resistance in the first fluid passageway as compared to the journal bearing, wherein the first fluid passageway connects to substantially an axial center of the journal bearing. 
     
     
         8 . The method as in  claim 1 , wherein creating the asymmetric pressure gradient comprises creating a lower pressure area within the reservoir as compared to a recirculation plenum, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         9 . The method as in  claim 1 , further comprising creating a pressure differential within the reservoir by employing an axial channel on at least a portion of an inner surface of the shield, the axial channel substantially extending from a recirculation plenum, to allow air within fluid to travel along the channels and be purged from the fluid, and to retain fluid, wherein the recirculation plenum is defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         10 . The method as in  claim 1 , further comprising employing a capillary seal extending from the shield to the outer component, the shield and the outer component having surfaces that are relatively tapered and converge toward a recirculation plenum, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         11 . The method as in  claim 1 , further comprising utilizing a single sided thrustplate with magnetic preload to reduce any power losses, wherein the radial member is the single sided thrustplate. 
     
     
         12 . A method of fluid sealing for use with a data storage device employing a fluid dynamic bearing motor comprising creating an asymmetric pressure gradient within an interfacial region of the fluid dynamic bearing motor, wherein the interfacial region is defined within an area including a journal bearing, a first fluid passageway, a second fluid passageway, and a reservoir, wherein the journal bearing, the first fluid passageway, and the second fluid passageway are connected for fluid recirculation, and are in fluid communication with the reservoir, wherein the reservoir maintains a lowest pressure of the interfacial region, and wherein:
 i.) the journal bearing is defined between an inner component and an outer component, the inner component and the outer component positioned for relative rotation;   ii.) the first fluid passageway is defined within the outer component;   iii.) the second fluid passageway is defined between the outer component and a radial member extending from the inner component;   iv.) the reservoir is defined between a shield and the outer component, the shield connected to one of the inner component and the outer component; and   v.) grooves are situated on at last one of a facing surface of the radial member and the outer component, to generate fluid pumping pressure to pump fluid from the second fluid passageway toward the inner component and into the journal bearing, when the inner component and the outer component are relatively rotating.   
     
     
         13 . The method as in  claim 12 , wherein creating an asymmetric pressure gradient comprises employing pumping grooves on a facing surface positioned at an outer diameter gap defined between the shield and an outer diameter of the radial member, to pump fluid from the outer diameter gap toward a recirculation plenum when the inner component and the outer component are relatively rotating, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         14 . The method as in  claim 12 , further comprising utilizing centrifugal force to act on fluid situated at an outer diameter gap defined between the shield and an outer diameter of the radial member, when the inner component and the outer component are relatively rotating. 
     
     
         15 . The method as in  claim 14 , wherein creating the asymmetric pressure gradient further comprises creating a third pressure area at an axial end of the journal bearing, and creating a fourth pressure area at an apex of grooves formed on a facing surface of the journal bearing, wherein when the inner component and the outer component are relatively rotating, the third pressure area has a lower pressure than the fourth pressure area. 
     
     
         16 . The method as in  claim 12 , wherein creating the asymmetric pressure gradient comprises creating a lower pressure area and a lower flow resistance in the first fluid passageway as compared to the journal bearing, wherein the first fluid passageway connects to substantially an axial center of the journal bearing. 
     
     
         17 . The method as in  claim 12 , wherein creating the asymmetric pressure gradient comprises creating a lower pressure area within the reservoir as compared to a recirculation plenum, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         18 . The method as in  claim 12 , further comprising creating a pressure differential within the reservoir by employing an axial channel on at least a portion of an inner surface of the shield, the axial channel substantially extending from a recirculation plenum, to allow air within fluid to travel along the channels and be purged from the fluid, and to retain fluid, wherein the recirculation plenum is defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         19 . The method as in  claim 12 , further comprising employing a capillary seal extending from the shield to the outer component, the shield and the outer component having surfaces that are relatively tapered and converge toward a recirculation plenum, the recirculation plenum defined by a junction joining the reservoir, the first fluid passageway and the second fluid passageway. 
     
     
         20 . The method as in  claim 12 , further comprising utilizing a single sided thrustplate with magnetic preload to reduce any power losses, wherein the radial member is the single sided thrustplate.