US4557160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic differential transmission
Assignee: Sundstrand Corp
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Filing: 1984-08-20
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Granted: 1985-12-10
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Expires: 2004-08-20
Abstract
Abstract A hydraulic differential transmission utilizing an input differential and having a hydrostatic transmission with a variable output speed to the input differential whereby the speed of the transmission drive output can be maintained constant with variable drive input speeds to the transmission. The hydraulic differential transmission has a pair of parallel drive trains between the drive shaft of the fixed displacement unit of the hydrostatic transmission and the input differential, with the two drive trains providing different drive ratios therebetween. A first drive train including an overrunning clutch provides a one to one drive ratio therebetween when operating at higher drive input speeds. The other drive train includes a second differential and a second overriding clutch providing a lesser drive ratio between the fixed displacement hydraulic unit and the first differential when operating at lower drive input speeds. The overrunning clutches enable a shift between drive trains at a shift point where the drive shaft of the fixed displacement hydaulic unit changes direction of rotation without any discontinuity in the drive at the shift point. The change in drive ratios for operation at the higher drive input speeds causes the hydraulic units of the hydrostatic transmission to operate at higher pressures and nearer their normal pressure capabilities.
Inventors
- 👤 Richard W. Reynolds
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:58
CPC Classifications
F; F16; F16H; F16H47/00; F16H47/02; F16H47/04; F16H37/00; F16H37/02; F16H37/06; F16H37/08; F16H37/0833; F16H37/084; F16H2037/0866; F16H2037/0873
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
133 words
A hydraulic differential transmission having a drive input and a drive output comprising, a first differential for transmitting a drive from the drive input to the drive output, a pair of hydraulic units hydraulically interconnected with one unit being of variable displacement and connected to the drive output and the other hydraulic unit being reversible in rotation, and two parallel drive trains for alternatively connecting said other hydraulic unit to said first differential with one drive train including an overrunning clutch engageable when said other hydraulic unit rotates in one direction and the other drive train including a second differential which freely rotates when the other hydraulic unit rotates in said one direction and which transmits a drive to said first differential when the other hydraulic unit rotates oppositely to said one direction.
Claim 2
Dependent Claim
133 words
A hydraulic differential transmission having a drive input and a drive output comprising, a first differential for transmitting a drive from the drive input to the drive output, a pair of hydraulic units hydraulically interconnected with one unit being of variable displacement and connected to the drive output and the other hydraulic unit being reversible in rotation, and two parallel drive trains for alternatively connecting said other hydraulic unit to said first differential with one drive train including an overrunning clutch engageable when said other hydraulic unit rotates in one direction and the other drive train including a second differential which freely rotates when the other hydraulic unit rotates in said one direction and which transmits a drive to said first differential when the other hydraulic unit rotates oppositely to said one direction.
Claim 3
Dependent Claim
146 words
A hydraulic differential transmission having a drive input means and a drive output means, a differential having plural relatively movable elements with a first element connected to the drive input means and a second element connected to the drive output means, a hydrostatic transmission having a pair of hydraulically interconnected hydraulic units with at least one hydraulic unit being of variable displacement and drivingly connected to said drive output means and said other hydraulic unit being operatively connected to a third element of said differential, the improvement comprising, a second differential in an operative connection of said other hydraulic unit to said third element of the first-mentioned differential, and means for either making or bypassing a drive connection between said other hydraulic unit and said third element through the second differential to vary the speed relation between the drive input means and said other hydraulic unit.
Claim 4
Dependent Claim
146 words
A hydraulic differential transmission having a drive input means and a drive output means, a differential having plural relatively movable elements with a first element connected to the drive input means and a second element connected to the drive output means, a hydrostatic transmission having a pair of hydraulically interconnected hydraulic units with at least one hydraulic unit being of variable displacement and drivingly connected to said drive output means and said other hydraulic unit being operatively connected to a third element of said differential, the improvement comprising, a second differential in an operative connection of said other hydraulic unit to said third element of the first-mentioned differential, and means for either making or bypassing a drive connection between said other hydraulic unit and said third element through the second differential to vary the speed relation between the drive input means and said other hydraulic unit.
Claim 5
Dependent Claim
47 words
A hydraulic differential transmission as defined in claim 2 wherein the drive output means is to operate at a constant speed while the speed of the drive input means may vary, and the displacement of said variable displacement hydraulic unit is adjustable to maintain said constant speed.
Claim 6
Dependent Claim
40 words
A hydraulic differential transmission as defined in claim 2 wherein said means for either making or bypassing said drive connection includes an overrunning clutch connected in parallel with said second differential between said third element and said other hydraulic unit.
Claim 7
Dependent Claim
68 words
A hydraulic differential transmission as defined in claim 4 wherein said second differential has plural relatively movable elements with one element connected to said third element and another element connected to said other hydraulic unit, and a second overrunning clutch connected to an additional element of said second differential and operative to lock said additional element against rotation in one direction of rotation of said other hydraulic unit.
Claim 8
Dependent Claim
140 words
A hydraulic differential transmission comprising, a planetary differential with plural relatively movable elements including a driven element, a drive output element, and a third element, a pair of hydraulic units which are hydraulically interconnected, one of said hydraulic units being of variable displacement and operable to cause rotation of the other hydraulic unit in either forward or reverse directions and at a speed within a range of speeds, said one hydraulic unit being operatively connected to said drive output element, and means including a second planetary differential connecting said other hydraulic unit to said third element to effect one drive ratio between the other hydraulic unit and said third element when said other hydraulic unit is operating in one rotative direction and to effect a different drive ratio when said other hydraulic unit is operating in an opposite rotative direction.
Claim 9
Dependent Claim
140 words
A hydraulic differential transmission comprising, a planetary differential with plural relatively movable elements including a driven element, a drive output element, and a third element, a pair of hydraulic units which are hydraulically interconnected, one of said hydraulic units being of variable displacement and operable to cause rotation of the other hydraulic unit in either forward or reverse directions and at a speed within a range of speeds, said one hydraulic unit being operatively connected to said drive output element, and means including a second planetary differential connecting said other hydraulic unit to said third element to effect one drive ratio between the other hydraulic unit and said third element when said other hydraulic unit is operating in one rotative direction and to effect a different drive ratio when said other hydraulic unit is operating in an opposite rotative direction.
Claim 10
Dependent Claim
43 words
A hydraulic differential transmission as defined in claim 6 wherein said one drive ratio exists when the speed relation between said driven element and said drive output element is below a predetermined value and the different drive ratio exists above said predetermined value.
Claim 11
Dependent Claim
34 words
A hydraulic differential transmission as defined in claim 7 wherein said means to effect said drive ratios includes an overrunning clutch operable to bypass said second planetary differential to achieve said different drive ratio.
Claim 12
Dependent Claim
49 words
A hydraulic differential transmission as defined in claim 8 wherein said means to effect said drive ratios further includes a second overrunning clutch to render said second planetary differential operative to transmit a drive from said other hydraulic unit to said third element to achieve said one drive ratio.
Claim 13
Dependent Claim
141 words
A hydraulic differential transmission having a drive input and a drive output, a first differential having plural relatively movable elements with a first element connected to the drive input and a second element connected to the drive output, a hydrostatic transmission having a pair of hydraulically interconnected hydraulic units with at least one hydraulic unit being of variable displacement and drivingly connected to said drive output and the other hydraulic unit being operatively connected to a third element of said differential, the improvement comprising, a second differential in an operative connection of said other hydraulic unit to said third element of the first-mentioned differential, and means for effecting different drive ratios between said other hydraulic unit and said first differential by either making or bypassing a drive connection between said other hydraulic unit and said third element through the second differential.
Claim 14
Dependent Claim
141 words
A hydraulic differential transmission having a drive input and a drive output, a first differential having plural relatively movable elements with a first element connected to the drive input and a second element connected to the drive output, a hydrostatic transmission having a pair of hydraulically interconnected hydraulic units with at least one hydraulic unit being of variable displacement and drivingly connected to said drive output and the other hydraulic unit being operatively connected to a third element of said differential, the improvement comprising, a second differential in an operative connection of said other hydraulic unit to said third element of the first-mentioned differential, and means for effecting different drive ratios between said other hydraulic unit and said first differential by either making or bypassing a drive connection between said other hydraulic unit and said third element through the second differential.
Claim 15
Dependent Claim
41 words
A hydraulic differential transmission as defined in claim 10 wherein one drive ratio exists when the speed relation between said drive input and said drive output is below a predetermined value and a different drive ratio exists above said predetermined value.
Claim 16
Dependent Claim
34 words
A hydraulic differential transmission as defined in claim 10 wherein said means to effect said different drive ratios includes an overrunning clutch operable to bypass said second differential to achieve said different drive ratio.
Claim 17
Dependent Claim
43 words
A hydraulic differential transmission as defined in claim 12 wherein said means to effect said different drive ratios further includes a second overrunning clutch to render said second differential operative to transmit a drive from said other hydraulic unit to said third element.
Claim 18
Dependent Claim
210 words
A hydraulic input differential transmission comprising, a drive input shaft, a driven output shaft, a planetary differential having a carrier connected to said drive input shaft and mounting a pair of rotatable meshing planet gears, said planetary differential having a pair of ring gears meshing one with each of said planet gears, one of said ring gears being operatively connected to said driven output shaft, a hydrostatic transmission having a pair of hydraulic units hydraulically interconnected, one of said hydraulic units being operatively connected to the driven output shaft and of variable displacement and having a movable wobbler movable overcenter to control the speed and direction of rotation of a gear driven by the other hydraulic unit, a first drive train including an overrunning clutch connecting said gear to the other of said ring gears, a second drive train including a second planetary differential connecting said gear to said other ring gear, and a second overrunning clutch permitting free rotation of the elements of the second planetary differential when said first drive train is operable in one direction of rotation of said gear and in the other direction of rotation of said gear locking one element of the second planetary differential to effect a drive through said second drive train.
Claim 19
Dependent Claim
210 words
A hydraulic input differential transmission comprising, a drive input shaft, a driven output shaft, a planetary differential having a carrier connected to said drive input shaft and mounting a pair of rotatable meshing planet gears, said planetary differential having a pair of ring gears meshing one with each of said planet gears, one of said ring gears being operatively connected to said driven output shaft, a hydrostatic transmission having a pair of hydraulic units hydraulically interconnected, one of said hydraulic units being operatively connected to the driven output shaft and of variable displacement and having a movable wobbler movable overcenter to control the speed and direction of rotation of a gear driven by the other hydraulic unit, a first drive train including an overrunning clutch connecting said gear to the other of said ring gears, a second drive train including a second planetary differential connecting said gear to said other ring gear, and a second overrunning clutch permitting free rotation of the elements of the second planetary differential when said first drive train is operable in one direction of rotation of said gear and in the other direction of rotation of said gear locking one element of the second planetary differential to effect a drive through said second drive train.
Claim 20
Dependent Claim
36 words
An input differential transmission as defined in claim 9 usable as a constant speed drive wherein the speed of the drive input shaft can vary while the speed of the driven output shaft is maintained constant.
Claim 21
Dependent Claim
206 words
An input differential transmission comprising, a drive input shaft, a driven output shaft, a planetary differential having a carrier connected to said drive input shaft and mounting a pair of rotatable meshing planet gears, said planetary differential having a pair of ring gears meshing one with each of said planet gears, one of said ring gears being operatively connected to said driven output shaft, a hydrostatic transmission having a pair of hydraulic units hydraulically interconnected, one of said hydraulic units being operatively connected to the driven output shaft and of variable displacement and having a movable wobbler movable overcenter to control the speed and direction of rotation of a gear driven by the other hydraulic unit, a first drive train connecting said gear to the other of said ring gears when said gear rotates in one direction, a second drive train including a second planetary differential connecting said gear to said other ring gear, and means permitting free rotation of the elements of the second planetary differential when said gear rotates in said one direction of rotation and for locking one element of the second planetary differential when said gear rotates in the other direction of rotation to effect a drive through said second drive train.
Claim 22
Dependent Claim
206 words
An input differential transmission comprising, a drive input shaft, a driven output shaft, a planetary differential having a carrier connected to said drive input shaft and mounting a pair of rotatable meshing planet gears, said planetary differential having a pair of ring gears meshing one with each of said planet gears, one of said ring gears being operatively connected to said driven output shaft, a hydrostatic transmission having a pair of hydraulic units hydraulically interconnected, one of said hydraulic units being operatively connected to the driven output shaft and of variable displacement and having a movable wobbler movable overcenter to control the speed and direction of rotation of a gear driven by the other hydraulic unit, a first drive train connecting said gear to the other of said ring gears when said gear rotates in one direction, a second drive train including a second planetary differential connecting said gear to said other ring gear, and means permitting free rotation of the elements of the second planetary differential when said gear rotates in said one direction of rotation and for locking one element of the second planetary differential when said gear rotates in the other direction of rotation to effect a drive through said second drive train.
References Cited (Backward Citations)
US2817250A
Cited
US2808737A
Cited
US2972905A
Cited
US3318172A
Cited
US3603176A
Cited
US3665788A
Cited
US3714846A
Cited
US3796111A
Cited
US3722324A
Cited
US3786696A
Cited
US3979972A
Cited
US4232568A
Cited
US4382392A
Cited
US4306467A
Cited
US4341131A
Cited
US4304151A
Cited
US4259881A
Cited
US4291592A
Cited
US4434681A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |