Mechanical translator with ultra low friction ferrofluid bearings

• US 6,833,780 B2
• Filed: 12/19/2003
• Issued: 12/21/2004
• Est. Priority Date: 02/19/2002
• Status: Expired due to Fees

• Current Assignee: Teledyne Scientific & Imaging, LLC (Teledyne Technologies Incorporated)
• Original Assignee: Rockwell Scientific Licensing LLC
• Inventors: Cheung, Jeffrey T.
• Primary Examiner(s): Barrera, Ramon M.
• Application Number:
  US10/741,667
• Publication Number:
  US 20040130422A1
• Time in Patent Office: 368 Days
• Field of Search: 335/285, 335/302-306, 310/90.5
• US Class Current: 335/302
• CPC Class Codes: C10M 171/06 Particles of special shape or size
• CPC Class Codes: C10M 2201/062 Oxides; Hydroxides; Carbonates or bicarbonates
• CPC Class Codes: C10M 2203/1006 used as base material
• CPC Class Codes: C10M 2207/12 having carboxyl groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10N 2010/14 Group 7
• CPC Class Codes: C10N 2010/16 Groups 8, 9, or 10
• CPC Class Codes: C10N 2020/01 Physico-chemical properties
• CPC Class Codes: C10N 2020/06 Particles of special shape or size
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2040/02 Bearings
• CPC Class Codes: C10N 2050/015 Dispersions of solid lubricants
• CPC Class Codes: F16C 29/02 Sliding-contact bearings
• CPC Class Codes: F16C 32/0637 by a magnetic field, e.g. ferrofluid bearings
• CPC Class Codes: F16C 33/1035 by a magnetic field acting on a magnetic liquid
• CPC Class Codes: H01F 1/44 of magnetic liquids, e.g. ferrofluids particles in a bonding agent H01F1/28, H01F1/36, H01F1/37
• CPC Class Codes: H02K 2201/18 Machines moving with multiple degrees of freedom
• CPC Class Codes: H02K 49/10 of the permanent-magnet type
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

A mechanical translator includes at least one magnet that is disposed on a substrate to carry a load and has a magnetic axis generally transverse to the substrate, establishing a magnetic field with maximum external density adjacent the substrate. An ultra low friction interface is obtained with ferrofluid bearings, such as a light mineral oil medium mixed with isoparaffinic acid, which establish a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. A controller of magnetic material can be placed on the opposite side of the substrate to control the movement of the magnets.

Claims

1. A mechanical translator, comprising:

a substrate, and

a magnet disposed for movement on said substrate, said magnet arranged to carry a load and having a magnetic axis generally transverse to said substrate, with a surface of the magnet facing said substrate, and

a ferrofluid concentrated between said magnet and said substrate, said ferrofluid extending across and in direct contact with said magnet surface to provide a low friction area support for said magnet to translate across said substrate,

wherein said translator has a critical angle of displacement from a horizontal static position of less than 1 degree.

2. The mechanical translator of claim 1, wherein said critical angle is less than 10 minutes.

3. The mechanical translator of claim 1, wherein said ferrofluid includes a light mineral oil medium.

4. The mechanical translator of claim 3, said ferrofluid further comprising isoparaffinic acid mixed with said light mineral oil.

5. The mechanical translator of claim 1, said ferrofluid having a viscosity less than 5 cp.

6. A mechanical translator comprising:

a substrate,

a magnet disposed for movement on said substrate, said magnet arranged to carry a load and having a magnetic axis generally transverse to said substrate, with a surface of the magnet facing said substrate,

a ferrofluid concentrated between said magnet and said substrate, said ferrofluid extending across and in direct contact with said magnet surface to provide a low friction area support for said magnet to translate across said substrate, and

a controller of magnetic material on the opposite side of said substrate from said magnet, said controller controlling the movement of said magnet.

7. The mechanical translator of claim 6, said substrate comprising a portion of an enclosure, with said magnet inside and said controller outside said enclosure.

8. A mechanical translator, comprising:

a substrate,

a magnet disposed for movement with respect to said substrate with a surface of said magnet facing said substrate, said magnet arranged to carry a load and establishing a magnetic field which has its maximum external density adjacent said substrate, and

a ferrofluid concentrated between said magnet and said substrate, said ferrofluid extending across and in direct contact with said magnet surface to provide a low friction area support for said magnet to translate across said substrate,

wherein said translator has a critical angle of displacement from a horizontal static position of less than 1 degree.

9. The mechanical translator of claim 8, wherein said critical angle is less than 10 minutes.

10. The mechanical translator of claim 8, wherein said ferrofluid includes a light mineral oil medium.

11. The mechanical translator of claim 10, said ferrofluid further comprising isoparaffinic acid mixed with said light mineral oil.

12. The mechanical translator of claim 8, said ferrofluid having a viscosity less than 5 cp.

13. A mechanical translator comprising:

a substrate,

a magnet disposed for movement with respect to said substrate with a surface of said magnet facing said substrate, said magnet arranged to carry a load and establishing a magnetic field which has its maximum external density adjacent said substrate,

a ferrofluid concentrated between said magnet and said substrate, said ferrofluid extending across and in direct contact with said magnet surface to provide a low friction area support for said magnet to translate across said substrate, and

a controller of magnetic material on the opposite side of said substrate from said magnet, said controller controlling the movement of said magnet.

14. The mechanical translator of claim 13, said substrate comprising a portion of an enclosure, with said magnet inside and said controller outside said enclosure.

15. A mechanical translator, comprising:

a substrate,

a plurality of magnets disposed for movement on said substrate and carrying a platform, said magnets having respective magnetic axes generally transverse to said substrate, with a respective surface of each magnet facing said substrate, and

a ferrofluid concentrated between each magnet and said substrate, said ferrofluid extending across and in direct contact with said respective surface of each magnet to provide respective low friction area supports for said magnets to translate across said substrate.

16. The mechanical translator of claim 15, wherein said magnets are connected to respective fixed locations on said platform.

17. The mechanical translator of claim 15, said platform comprising a magnetic material.

18. The mechanical translator of claim 15, said platform comprising a nonmagnetic material.

19. The mechanical translator of claim 18, said platform comprising a magnetic field shielding alloy.

20. The mechanical translator of claim 15, wherein said translator has a critical angle of displacement from a horizontal static position of less than 1 degree.

21. The mechanical translator of claim 20, wherein said critical angle is less than 10 minutes.

22. The mechanical translator of claim 15, further comprising a controller of magnetic material on the opposite side of said substrate from said magnets and platform, said controller controlling the movement of said magnets and platform.

23. The mechanical translator of claim 22, said substrate comprising a portion of an enclosure, with said magnets and platform inside said enclosure and said controller outside.

24. A mechanical translator, comprising:

a substrate,

a plurality of magnets disposed for movement with respect to said substrate and carrying a platform, said magnets establishing respective magnetic fields which have their maximum external densities adjacent said substrate, and

a ferrofluid concentrated between each magnet and said substrate, said ferrofluid extending across and in direct contact with said respective surface of each magnet to provide respective low friction area supports for said magnets to translate across said surface.

25. The mechanical translator of claim 24, wherein said magnets are connected to respective fixed locations on said platform.

26. The mechanical translator of claim 24, said platform comprising a magnetic material.

27. The mechanical translator of claim 24, said platform comprising a nonmagnetic material.

28. The mechanical translator of claim 27, said platform comprising a magnetic field shielding alloy.

29. The mechanical translator of claim 24, wherein said translator has a critical angle of displacement from a horizontal static position of less than 1 degree.

30. The mechanical translator of claim 29, wherein said critical angle is less than 10 minutes.

31. The mechanical translator of claim 24, further comprising a controller of magnetic material on the opposite side of said substrate from said magnets and platform, said controller controlling the movement of said magnets and platform.

32. The mechanical translator of claim 31, said substrate comprising a portion of an enclosure, with said magnets and platform inside said enclosure and said controller outside.

33. Vapor deposition apparatus, comprising:

a vacuum chamber having a floor,

at least one magnet disposed for movement on said floor and carrying a platform for a substrate, each magnet having a magnetic axis generally transverse to said floor, with a respective surface of each magnet facing said floor,

a ferrofluid concentrated between each said magnet and said floor, said ferrofluid extending across and in direct contact with said respective surfaces of each magnet to provide respective low friction area supports for said magnets to translate across said floor,

a vapor source for depositing a thin film on a substrate carried by said platform, and

a controller of magnetic material outside said chamber on the opposite side of said floor from said magnets, said controller arranged to translate to impart a corresponding translation to said magnets and platform.

34. The vapor deposition apparatus of claim 33, wherein said translator has a critical angle of displacement from a horizontal static position of less than 1 degree.

35. The vapor deposition apparatus of claim 34, wherein said critical angle is less than 10 minutes.

36. A mechanical translator, comprising:

a substrate,

at least one magnet disposed for movement on said substrate and arranged to carry a load, each magnet having a magnetic axis at an angle of at least 45°

to said substrate and a critical angle of displacement from a horizontal static position of less than 1 degree, with a surface of the magnet facing said substrate, and

a ferrofluid disposed between each said magnet and said substrate, said ferrofluid extending across and in direct contact with each said magnet surface to provide a low friction area support for each said magnet to translate across said substrate.

37. The mechanical translator of claim 36, wherein said critical angle is less than 10 minutes.

38. The mechanical translator of claim 36, comprising a plurality of said magnets carrying a common load platform.

39. The mechanical translator of claim 36, further comprising a controller of magnetic material on the opposite side of said substrate from said at least one magnet, said controller controlling the movement of said at least one magnet.

40. The mechanical translator of claim 39, said substrate comprising a portion of an enclosure, with said at least one magnet inside and said controller outside said enclosure.