US4781077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stable intershaft squeeze film damper
Assignee: Massachusetts Institute of Technology
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Filing: 1986-12-19
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Granted: 1988-11-01
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Expires: 2006-12-19
Abstract
Abstract A dual shaft rotating assembly typically used in aircraft engines is provided with a stable intershaft squeeze film damper for reducing vibration. The assembly includes a housing, a first shaft rotatable about an axis of rotation, a second shaft concentric with the first shaft and rotatable about the same axis of rotation, bearings for supporting each of the shafts from the housing, a squeeze film damper positioned between the shafts and including an annular region containing an oil film for attenuating vibration, and apparatus for maintaining the damping fluid stationary relative to the housing. The squeeze film damper includes an inner ring and an outer ring which define the annular region between them. A first intershaft bearing is coupled between the first shaft and the inner ring, and a second intershaft bearing is coupled between the second shaft and the outer ring. The inner and outer rings are maintained stationary by squirrel cages coupled to the housing. The stationary oil film provides stable damping for all practical rotating speeds of the shafts.
Inventors
- 👤 Aly El-Sahfei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:10
CPC Classifications
F; F01; F01D; F01D25/00; F01D25/16; F01D25/162; F01D25/164; F16; F16C; F16C19/00; F16C19/54; F16C19/55; F16C27/00; F16C27/04; F16C27/045; F16F; F16F15/00; F16F15/02; F16F15/023; F16F15/0237; F16F15/10; F16C19/02; F16C19/14; F16C19/16; F16C19/163; F16C2360/00; F16C2360/23; Y; Y10; Y10T; Y10T74/00; Y10T74/21; Y10T74/2121; Y10T74/2122; Y10T74/2123; Y10T74/2126
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
106 words
A dual shaft rotating assembly having a stable intershaft squeeze film damper for attenuating vibration, comprising: a housing; a first shaft rotatable about an axis of rotation; a second shaft concentric with said first shaft and rotatable about said axis of rotation; means for supporting each of said shafts from said housing while permitting each of said shafts to rotate independently; squeeze film damper means positioned between said first shaft and said second shaft and defining an annular region containing a damping fluid for attenuating vibration of said first shaft and said second shaft; and means for maintaining said damping fluid stationary relative to said housing.
Claim 2
Dependent Claim
106 words
A dual shaft rotating assembly having a stable intershaft squeeze film damper for attenuating vibration, comprising: a housing; a first shaft rotatable about an axis of rotation; a second shaft concentric with said first shaft and rotatable about said axis of rotation; means for supporting each of said shafts from said housing while permitting each of said shafts to rotate independently; squeeze film damper means positioned between said first shaft and said second shaft and defining an annular region containing a damping fluid for attenuating vibration of said first shaft and said second shaft; and means for maintaining said damping fluid stationary relative to said housing.
Claim 3
Dependent Claim
44 words
A dual shaft rotating assembly as defined in claim 1 wherein said maintaining means comprises a first intershaft bearing between said first shaft and said squeeze film damper means, and a second intershaft bearing between said second shaft and said squeeze film damper means.
Claim 4
Dependent Claim
27 words
A dual shaft rotating assembly as defined in claim 2 wherein said maintaining means further includes means for coupling said squeeze film damper means to said housing.
Claim 5
Dependent Claim
57 words
A dual shaft rotating assembly as defined in claim 2 wherein said squeeze film damper means includes an inner ring coupled to said first intershaft bearing and having an outer surface, and an outer ring coupled to said second intershaft bearing and having an inner surface, said outer surface and said inner surface defining said annular region.
Claim 6
Dependent Claim
41 words
A dual shaft rotating assembly as defined in claim 4 wherein said maintaining means further includes an inner squirrel cage coupled between said inner ring and said housing and an outer squirrel cage coupled between said outer ring and said housing.
Claim 7
Dependent Claim
22 words
A dual shaft rotating assembly as defined in claim 4 further including means for supplying said damping fluid to said annular region.
Claim 8
Dependent Claim
26 words
A dual shaft rotating assembly as defined in claim 6 further including means for sealing said annular region to prevent leakage of said damping fluid therefrom.
Claim 9
Dependent Claim
16 words
A dual shaft rotating assembly as defined in claim 7 wherein said damping fluid comprises oil.
Claim 10
Dependent Claim
26 words
A dual shaft rotating assembly as defined in claim 2 wherein said first intershaft bearing and said second intershaft bearing each comprise a rolling element bearing.
Claim 11
Dependent Claim
26 words
A dual shaft rotating assembly as defined in claim 2 wherein said first shaft and said second shaft rotate in opposite directions relative to said housing.
Claim 12
Dependent Claim
23 words
A dual shaft rotating assembly as defined in claim 2 wherein said first shaft and said second shaft rotate in the same direction.
Claim 13
Dependent Claim
164 words
A dual shaft rotating assembly having a stable intershaft squeeze film damper for attenuating vibration, comprising: a housing; a first shaft for rotation at a first angular speed about an axis of rotation; first bearing means for supporting said first shaft from said housing and for permitting rotation of said first shaft relative to said housing; a second shaft concentric with said first shaft for rotation at a second angular speed about said axis of rotation; second bearing means for supporting said second shaft from said housing and for permitting rotation of said second shaft relative to said housing; squeeze film damper means positioned between said first shaft and said second shaft and defining an annular region containing a damping fluid; a first intershaft bearing between said first shaft and said squeeze film damper means; a second intershaft bearing between said second shaft and said squeeze film damper means; and means for preventing rotation of said squeeze film damper means relative to said housing.
Claim 14
Dependent Claim
164 words
A dual shaft rotating assembly having a stable intershaft squeeze film damper for attenuating vibration, comprising: a housing; a first shaft for rotation at a first angular speed about an axis of rotation; first bearing means for supporting said first shaft from said housing and for permitting rotation of said first shaft relative to said housing; a second shaft concentric with said first shaft for rotation at a second angular speed about said axis of rotation; second bearing means for supporting said second shaft from said housing and for permitting rotation of said second shaft relative to said housing; squeeze film damper means positioned between said first shaft and said second shaft and defining an annular region containing a damping fluid; a first intershaft bearing between said first shaft and said squeeze film damper means; a second intershaft bearing between said second shaft and said squeeze film damper means; and means for preventing rotation of said squeeze film damper means relative to said housing.
Claim 15
Dependent Claim
57 words
A dual shaft rotating assembly as defined in claim 12 wherein said squeeze film damper means includes an inner ring coupled to said first intershaft bearing and having an outer surface, and an outer ring coupled to said second intershaft bearing and having an inner surface, said outer surface and said inner surface defining said annular region.
Claim 16
Dependent Claim
41 words
A dual shaft rotating assembly as defined in claim 13 wherein said rotation preventing means includes an inner squirrel cage coupled between said inner ring and said housing and an outer squirrel cage coupled between said outer ring and said housing.
Claim 17
Dependent Claim
22 words
A dual shaft rotating assembly as defined in claim 13 further including means for supplying said damping fluid to said annular region.
Claim 18
Dependent Claim
26 words
A dual shaft rotating assembly as defined in claim 15 further including means for sealing said annular region to prevent leakage of said damping fluid therefrom.
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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) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |