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US5019738A Expired / Lapsed US ⏱️ 0.0 years remaining

Self-pressurizing gas supported surface-roughness bearing

Assignee: Novanta Inc
•
Filing: 1990-07-16
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Granted: 1991-05-28
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Expires: 2010-07-16
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Abstract

Abstract A self-pressurizing gas supported bearing includes a cylindrical bearing sleeve having a longitudinal axis and a cylindrical inner surface forming a first bearing surface with a random surface texture having a first R a roughness profile. A cylindrical bearing shaft is positioned coaxially within the bearing sleeve and includes a cylindrical outer surface forming a second bearing surface with a random surface texture having a second R a roughness profile. The sum of the first and second R a roughness profiles falls within the range of from about eighteen to sixty. A drive system establishes a relative rotational velocity between the bearing sleeve and the bearing shaft, generating a bearing stiffness force which causes the overlapping bearing surfaces to lift off and break contact. The bearing sleeve and shaft are dimensioned to maintain a predetermined means spacing between the sleeve and shaft. The bearing may also take the form of a linear bearing or other cylindrical configurations.

Inventors

  • 👤 August O. Weilbach
  • 👤 Derald F. Hanson
  • 👤 C. Dwight Smith

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 15:20
CPC Classifications
H; H02; H02K; H02K7/00; H02K7/08; H02K7/09; F; F16; F16C; F16C17/00; F16C17/02; F16C17/026; F16C32/00; F16C32/04; F16C32/0402; F16C32/0406; F16C32/0408; F16C32/0423; F16C32/0427; F16C33/00; F16C33/02; F16C33/04; F16C33/06; F16C33/10; F16C33/1005; H02K5/00; H02K5/04; H02K5/16; H02K5/167; H02K5/1675; F16C2240/00; F16C2240/40; F16C2240/54

Claims Analysis

Total Claims: 25
Claim 1
Independent Claim 221 words
A self-pressurizing gas supported bearing comprising: a. a cylindrical bearing sleeve having a longitudinal axis and a cylindrical inner surface including a first bearing surface with a random surface texture having a first R a roughness profile; b. a cylindrical bearing shaft positioned coaxially within the bearing sleeve and having a cylindrical outer surface including a second bearing surface with a random surface texture having a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about 18 to about 60 and wherein the bearing sleeve and shaft are aligned along the longitudinal axis such that the first and second bearing surfaces overlap; c. drive means for establishing a relative rotational velocity between the bearing sleeve and the bearing shaft where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces of the sleeve and shaft to lift off and break contact; and d. the bearing sleeve and shaft having a geometry to maintain a predetermined mean spacing between the first bearing surface of the sleeve and the overlapping second bearing surface of the shaft of from a minimum of about seventy-five micro inches to a maximum mean spacing where the first and second bearing surfaces fail to lift off and break contact.
Claim 2
Dependent Claim 221 words
A self-pressurizing gas supported bearing comprising: a. a cylindrical bearing sleeve having a longitudinal axis and a cylindrical inner surface including a first bearing surface with a random surface texture having a first R a roughness profile; b. a cylindrical bearing shaft positioned coaxially within the bearing sleeve and having a cylindrical outer surface including a second bearing surface with a random surface texture having a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about 18 to about 60 and wherein the bearing sleeve and shaft are aligned along the longitudinal axis such that the first and second bearing surfaces overlap; c. drive means for establishing a relative rotational velocity between the bearing sleeve and the bearing shaft where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces of the sleeve and shaft to lift off and break contact; and d. the bearing sleeve and shaft having a geometry to maintain a predetermined mean spacing between the first bearing surface of the sleeve and the overlapping second bearing surface of the shaft of from a minimum of about seventy-five micro inches to a maximum mean spacing where the first and second bearing surfaces fail to lift off and break contact.
Claim 3
Dependent Claim 34 words
The bearing of claim 1 further including longitudinal alignment means coupled to the bearing sleeve and to tee bearing shaft for maintaining a fixed longitudinal alignment between the bearing sleeve and the bearing shaft.
Claim 4
Dependent Claim 54 words
The bearing of claim 2 wherein the bearing sleeve includes a first end section, wherein the bearing shaft includes a first end section and wherein the longitudinal alignment means includes a first thrust bearing coupled to the first end section of the bearing sleeve and to the first end section of the bearing shaft.
Claim 5
Dependent Claim 23 words
The bearing of claim 1 wherein the first bearing surface includes a first length, and the second bearing surface includes a second length.
Claim 6
Dependent Claim 45 words
The bearing of claim 4 wherein the bearing shaft is rotationally fixed, wherein the drive means rotates the bearing sleeve about the bearing shaft, and wherein the first length of the rotating bearing sleeve is less than the second length of the fixed bearing shaft.
Claim 7
Dependent Claim 45 words
The bearing of claim 4 wherein the bearing sleeve is rotationally fixed, wherein the drive means rotates the bearing shaft relative to the fixed bearing sleeve, and wherein the first length of the bearing sleeve is less than the second length of the bearing shaft.
Claim 8
Dependent Claim 15 words
The bearing of claim 3 wherein the thrust bearing includes a magnetic thrust bearing assembly.
Claim 9
Dependent Claim 43 words
The bearing of claim 7 wherein the magnetic thrust bearing assembly includes: a. a first annular magnet coupled to the first end section of the bearing shaft; and b. a second annular magnet coupled to the first end section of the bearing shaft.
Claim 10
Dependent Claim 38 words
The bearing of claim 8 wherein the first and second annular magnets each include north and south poles and wherein the first and second annular magnets are placed in close proximity to each other with matching magnetic poles.
Claim 11
Dependent Claim 51 words
The bearing of claim 9 wherein: a. the bearing shaft and the bearing sleeve each include a second end section; and b. the longitudinal alignment means includes a second thrust bearing coupled to the second end section of the bearing sleeve and to the second end section of the bearing shaft.
Claim 12
Dependent Claim 16 words
The bearing of claim 10 wherein the second thrust bearing includes a magnetic thrust bearing assembly.
Claim 13
Dependent Claim 42 words
The bearing of claim 11 wherein the magnetic thrust bearing assembly includes: a. a first annular magnet coupled to the second section of the bearing shaft; and b. a second annular magnet coupled to the second end section of the bearing shaft.
Claim 14
Dependent Claim 250 words
Apparatus for rotating a load having a longitudinal axis extending through a center of gravity, comprising: a. a bearing assembly coupled to rotate the load about the longitudinal axis and including i. a cylindrical bearing sleeve centrally aligned with the longitudinal axis and having a cylindrical surface including a first bearing surface including a random surface texture with a first R a roughness profile; ii. a cylindrical bearing shaft positioned coaxially within the bearing sleeve and having a cylindrical outer surface with a second bearing surface including a random surface texture with a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about 18 to about 60 and wherein the bearing sleeve and bearing shaft are aligned along the longitudinal axis such that the first and second bearing surfaces overlap; b. drive means for establishing a relative rotational velocity between the bearing sleeve and the bearing shaft where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces of the sleeve and shaft to lift off and break contact; and c. the bearing sleeve and shaft having a geometry dimensional to maintain a predetermined mean spacing between the first bearing surface of the sleeve and the overlapping second bearing surface of the shaft of from a minimum of about seventy-five micro inches to a maximum mean spacing where the first and second bearing surfaces fail to lift off and break contact.
Claim 15
Dependent Claim 250 words
Apparatus for rotating a load having a longitudinal axis extending through a center of gravity, comprising: a. a bearing assembly coupled to rotate the load about the longitudinal axis and including i. a cylindrical bearing sleeve centrally aligned with the longitudinal axis and having a cylindrical surface including a first bearing surface including a random surface texture with a first R a roughness profile; ii. a cylindrical bearing shaft positioned coaxially within the bearing sleeve and having a cylindrical outer surface with a second bearing surface including a random surface texture with a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about 18 to about 60 and wherein the bearing sleeve and bearing shaft are aligned along the longitudinal axis such that the first and second bearing surfaces overlap; b. drive means for establishing a relative rotational velocity between the bearing sleeve and the bearing shaft where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces of the sleeve and shaft to lift off and break contact; and c. the bearing sleeve and shaft having a geometry dimensional to maintain a predetermined mean spacing between the first bearing surface of the sleeve and the overlapping second bearing surface of the shaft of from a minimum of about seventy-five micro inches to a maximum mean spacing where the first and second bearing surfaces fail to lift off and break contact.
Claim 16
Dependent Claim 206 words
A self-pressurizing gas supported bearing comprising: a. a first bearing element having a longitudinal axis and a curved inner bearing surface with a random surface texture having a first R a roughness profile; b. a second bearing element positioned coaxially within the first bearing element and having a curved outer bearing surface with a random surface texture having a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about eighteen to about sixty and wherein the first and second bearing elements are aligned along the longitudinal axis such that the inner and outer bearing surfaces overlap; c. drive means for establishing a relative rotational velocity between the inner and outer bearing surfaces where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces to lift off and break contact; and d. the inner and outer bearing surfaces having a geometry dimensioned to maintain a predetermined mean spacing between the overlapping surfaces of the first and second bearing elements of from a minimum mean spacing of about seventy-five microinches to a maximum mean spacing where the inner and outer bearing surfaces fail to lift off and break contact.
Claim 17
Dependent Claim 206 words
A self-pressurizing gas supported bearing comprising: a. a first bearing element having a longitudinal axis and a curved inner bearing surface with a random surface texture having a first R a roughness profile; b. a second bearing element positioned coaxially within the first bearing element and having a curved outer bearing surface with a random surface texture having a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about eighteen to about sixty and wherein the first and second bearing elements are aligned along the longitudinal axis such that the inner and outer bearing surfaces overlap; c. drive means for establishing a relative rotational velocity between the inner and outer bearing surfaces where the relative rotational velocity generates a bearing stiffness force and causes the overlapping bearing surfaces to lift off and break contact; and d. the inner and outer bearing surfaces having a geometry dimensioned to maintain a predetermined mean spacing between the overlapping surfaces of the first and second bearing elements of from a minimum mean spacing of about seventy-five microinches to a maximum mean spacing where the inner and outer bearing surfaces fail to lift off and break contact.
Claim 18
Dependent Claim 35 words
The bearing of claim 14 further including longitudinal alignment means coupled to the first bearing element and to the second bearing element for maintaining a fixed longitudinal alignment between the inner and outer bearing surfaces.
Claim 19
Dependent Claim 20 words
The bearing of claim 14 wherein the maximum mean spacing is equal to or less than about three hundred microinches.
Claim 20
Dependent Claim 18 words
The bearing of claim 14 wherein the curved inner and outer bearing surfaces are configured as concentric cylinders.
Claim 21
Dependent Claim 18 words
The bearing of claim 14 wherein the curved inner and outer bearing surfaces are configured as concentric cones.
Claim 22
Dependent Claim 19 words
The bearing of claim 14 wherein the curved inner and outer bearing surfaces are configured as concentric spheric sections.
Claim 23
Dependent Claim 26 words
The bearing of claim 15 wherein the first bearing element includes a cylindrical bearing sleeve and wherein the second bearing element includes a cylindrical bearing shaft.
Claim 24
Dependent Claim 54 words
The bearing of claim 20 wherein the bearing sleeve includes a first end section, wherein the bearing shaft includes a first end section and wherein the longitudinal alignment means includes a first thrust bearing coupled to the first end section of the bearing sleeve and to the first end section of the bearing shaft.
Claim 25
Dependent Claim 171 words
The bearing of claim 21 including: a. a first thrust bearing element coupled to and extending radially outward from the first end section of the bearing sleeve and oriented perpendicular to the longitudinal axis with a random surface texture having a first R a roughness profile; b. a second thrust bearing element coupled to and extending radially outward from the first end section of the bearing shaft and oriented perpendicular to the longitudinal axis and substantially parallel to the first thrust bearing element with a random surface texture having a second R a roughness profile, wherein the sum of the first and second R a roughness profiles falls within the range of from about 18 to about 60 and wherein the first and second thrust bearing elements overlap; and c. the first and second thrust bearing elements each having a geometry dimensioned to maintain a predetermined means spacing between the overlapping surfaces to generate a thrust pressure adequate to maintain a relatively fixed longitudinal alignment between the bearing shaft and sleeve.

References Cited (Backward Citations)

US3284144A Cited
US3899223A Cited
US4487514A Cited
US4538081A Cited
US4552417A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-05-27 1994-11-26 1995-05-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-05-27 1998-11-26 1999-05-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-05-27 2002-11-26 2003-05-28 $7700.00 Window Closed / Lapsed

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