Information recording apparatus with a non-Newtonian liquid bearing

• US 5,097,368 A
• Filed: 12/20/1989
• Issued: 03/17/1992
• Est. Priority Date: 10/17/1988
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Conner Peripherals Incorporated (Whitehouse Group Ltd.)
• Inventors: Lemke, James U., French, William W.
• Primary Examiner(s): Wolff, John H.
• Application Number:
  US07/453,312
• Time in Patent Office: 818 Days
• Field of Search: 360/97.02, 360/102-104
• US Class Current: 360/234.1
• CPC Class Codes: G11B 21/21 with provision for maintaining desired spacing of head from record carrier, e.g. fluid-dynamic spacing, slider
• CPC Class Codes: G11B 23/505 of disk carriers
• CPC Class Codes: G11B 33/148 Reducing friction, adhesion, drag
• CPC Class Codes: G11B 5/6005 Specially adapted for spacing from a rotating disc using a fluid cushion

Abstract

An information storage apparatus is disclosed for reading and/or writing information on a rigid disk, which includes a non-Newtonian liquid bearing interface between a transducer and a storage medium, instead of a conventional air or Newtonian liquid bearing. The non-Newtonian liquid has a composition which exhibits plastic or pseudoplastic flow at high rates of shear. Preferably, the liquid is of the class of compounds whose viscosity shows a negative dependence on shear rate. Thus, as the relative speed of the transducer and the storage medium increases, while their relative spacing decreases, the increasing shear rate to which the liquid bearing is subjected causes the viscosity of the liquid to reduce. Resultantly, very low flying heights can be achieved, which increases the potential storage density on the storage medium, while the reduced drag exerted on the transducer by the lowered viscosity greatly reduces the power required to rotate the medium.

Claims

1. An information storage system comprising:

a substantially rigid, moveable storage medium;

means for inducing movement of said storage medium for information transfer;

a transducer means for being supported in a spaced relationship with said storage medium in response to said movement of said medium in order to provide information for storage on said storage medium or to receive stored information from said storage medium;

loading means for exerting a loading force on said transducer means, which is directed toward said storage medium; and

a non-Newtonian liquid bearing means between said storage medium and said transducer means and cooperating with said loading means for supporting said transducer means in said spaced relationship during said movement of said storage medium.

2. An information recording system, including:

a rigid storage medium;

means for inducing rotation of said storage medium;

a transducer means for being positioned in a spaced relationship with said storage medium in response to said rotation to provide information for storage on said storage medium or to receive stored information from said storage medium;

load means for exerting a positioning force on said transducer means which is directed toward said storage medium; and

a plastic or pseudoplastic liquid spacing means between said storage medium and said transducer means and cooperating with said positioning means for supporting said transducer means in said spaced relationship in response to said rotation.

3. An information storage system comprising:

a rigid storage medium for recording information signals;

transducer means closely spaced from said storage medium for transducing information signals to be stored on and read out from said storage medium;

load means for providing a load force to said transducer means, said load force being directed toward said storage medium;

means for moving said storage medium with respect to said transducer means; and

non-Newtonian fluid means disposed between and contacting said storage medium and said transducer means for providing hydrodynamic force opposing said load force so that said transducer means is spaced from said storage medium at a distance of less than 6.0 microinches.

4. The information storage system of claim 3, wherein said non-Newtonian fluid means includes a pseudoplastic fluid.

5. The information storage system of claim 3, wherein said non-Newtonian fluid means includes a plastic liquid in which the apparent viscosity of the liquid decreases with the shear rate to which the plastic liquid is subjected, the shear rate being determined by v/y, where v is the velocity of the storage medium with respect to the transducer means and y is the distance between said transducer means and said storage medium.

6. The information storage system of claim 3, wherein said non-Newtonian fluid means includes a liquid whose apparent viscosity decreases with an increase in the shear rate to which the liquid is subjected, the shear rate being determined by v/y, where v is the velocity of the storage medium with respect to the transducer means and y is the distance between said transducer means and said storage medium.

7. A information recording system, including:

a rigid disk;

means for inducing rotation of said rigid disk;

a transducer carrier for being supported in a closely spaced relationship with said rigid disk for information exchange therewith in response to said rotation;

means for exerting a positioning force on said transducer carrier, the positioning force being directed toward the rigid disk; and

a non-Newtonian liquid between the transducer carrier and the rigid disk for supporting the transducer carrier at a distance of between 6.0 and 0.5 microinches from the rigid disk.

8. The information recording system of claim 7, wherein the non-Newtonian liquid is a plastic liquid.

9. The information recording system of claim 7, wherein the non-Newtonian liquid is a pseudoplastic liquid.

10. The information recording system of claim 7, wherein the non-Newtonian liquid is a member of the group containing perfluoropolymers, perfluoropolyethers, and oxirametrifluoro-homopolymers.

11. The information recording system of claim 7, wherein the non-Newtonian liquid is a liquid fluorocarbon.

12. A disk drive system, comprising:

a rigid disk having a major surface;

means for transferring data from said major surface, said means for transferring including a transducer supported in a closely spaced relationship with respect to said major surface, said means for transferring having a support surface;

means for inducing rotation of said disk; and

a liquid bearing material provided in a thin layer on said major surface for supporting said means for transferring in said closely spaced relationship in response to said rotation, said closely spaced relationship being a distance substantially perpendicular to said major surface and between said support surface and said major surface of less than about 6 microinches.

13. The disk drive system of claim 12, wherein said liquid bearing material is a non-Newtonian liquid bearing material.

14. The disk drive system of claim 12, wherein said liquid bearing material has a viscosity, said viscosity being non-linear in response to said rotation.

15. An information recording system, including:

a rigid Winchester-type disk with a recording surface;

a transducer carrier for being supported in a closely spaced relationship with said recording surface;

a transducer mounted to said transducer carrier for information transfer with said recording surface;

means for rotating said rigid disk for said information transfer; and

a relatively thin layer of liquid bearing material on the rigid disk for supporting the transducer carrier at a distance of about 6 microinches, or less, with respect to said recording surface when said rigid disk is rotating.

16. The information recording system of claim 15, wherein said liquid bearing material is a non-Newtonian liquid bearing material.

17. The information recording system of claim 16, wherein said non-Newtonian liquid bearing material is a plastic material or a pseudoplastic material.

18. The information recording system of claim 15, further including:

means for exerting a positioning force on said transducer carrier;

said positioning force being directed substantially toward said recording surface; and

said positioning force being in a range between about 3 grams and about 45 grams.

19. The information recording system of claim 18, said liquid bearing material including a non-Newtonian liquid.