Patent US4957016A successfully refreshed from Google Patents.
US4957016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle transmission, particularly for an agricultural tractor
Assignee: FiatGeotech Technologie per la Terra SpA
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Filing: 1990-03-22
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Granted: 1990-09-18
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Expires: 2010-03-22
Abstract
Abstract A transmission for an agricultural tractor featuring a large number of gears and comprising a first six-gear stage and a second reverse-reduction stage having three forward and one reverse speed ranges. The first stage comprises a pair of drive shafts selectively connectable to an input shaft via respective hydraulic clutches and to an output shaft via constant mesh gears respectively defining the odd and even number gears and engaging the output shaft via sliding couplings controlled by three-position hydraulic actuators. The actuators are operated by respective pairs of on-off solenoid valves supplied via a proportional-response solenoid valve, further proportional-response solenoid valves controlling engagement and release of the aforementioned clutches. All the aforementioned solenoid valves are controlled by an electronic control unit for appropriately controlling engagement of the clutches and actuators as a function of the actual service conditions of the tractor.
Inventors
- 👤 Giuseppe Amedei
- 👤 Angelo Rondelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:25
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/68; F16H61/684; F16H61/688; F16H3/00; F16H3/006; F16H37/00; F16H37/02; F16H37/04; F16H37/042; F16H37/043; F16H61/02; F16H61/0202; F16H61/0248; F16H2200/00; F16H2200/003; F16H2200/0052; F16H2306/00; F16H63/00; F16H63/02; F16H63/30; F16H63/3023; F16H63/3026; Y; Y10; Y10T; Y10T74/00; Y10T74/19; Y10T74/19219; Y10T74/19251; Y10T74/19256; Y10T74/1926; Y10T74/19284; Y10T74/19288
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
214 words
A vehicle transmission, particularly for an agricultural tractor, comprising an input shaft at least a first stage having two drive shafts selectively connectable to said input shaft via respective first hydraulic clutch means, an output shaft angularly connectable to each said drive shaft via a number of transmission ratios defined by respective constant mesh gears, and second selective clutch means for each pair of adjacent said gears, operated by respective three-position hydraulic actuators; and control means for controlling said first clutch means and said hydraulic actuators; characterised by the fact that said control means comprise two on-off solenoid valves (E1, E3, E5, E2; E4, E6) for each said hydraulic actuator (A13, A52, A46), each designed to control engagement of a respective transmission ratio; two proportional-response solenoid valves (E8, E9) for engaging and releasing respective said first clutch means (Fp, Fd) on said drive shafts (4, 5); at least a third proportional-response solenoid valve (E7) for regulating supply pressure to said on-off solenoid valves (E1,. . .,E6); and a control unit (45) designed to control said solenoid valves (E1, . . . ,E9) in such a manner as to engage and release said first and second clutch means (Fp, Fd; M13, M52, M46) according to predetermined laws depending on the service condition of said vehicle.
Claim 2
Dependent Claim
214 words
A vehicle transmission, particularly for an agricultural tractor, comprising an input shaft at least a first stage having two drive shafts selectively connectable to said input shaft via respective first hydraulic clutch means, an output shaft angularly connectable to each said drive shaft via a number of transmission ratios defined by respective constant mesh gears, and second selective clutch means for each pair of adjacent said gears, operated by respective three-position hydraulic actuators; and control means for controlling said first clutch means and said hydraulic actuators; characterised by the fact that said control means comprise two on-off solenoid valves (E1, E3, E5, E2; E4, E6) for each said hydraulic actuator (A13, A52, A46), each designed to control engagement of a respective transmission ratio; two proportional-response solenoid valves (E8, E9) for engaging and releasing respective said first clutch means (Fp, Fd) on said drive shafts (4, 5); at least a third proportional-response solenoid valve (E7) for regulating supply pressure to said on-off solenoid valves (E1,. . .,E6); and a control unit (45) designed to control said solenoid valves (E1, . . . ,E9) in such a manner as to engage and release said first and second clutch means (Fp, Fd; M13, M52, M46) according to predetermined laws depending on the service condition of said vehicle.
Claim 3
Dependent Claim
78 words
A transmission as claimed in claim 1, characterised by the fact that said first clutch means compromise a clutch (Fd) assigned to one of said drive shafts (5) connected to said gears (R1, R3, R5) defining the odd number transmission ratios; and a clutch (Fp) assigned to the other side drive shaft (4) connected to said gears (R2, R4, R6) defining the even number transmission ratios; one of said clutches being normally engaged, and the other normally released.
Claim 4
Dependent Claim
104 words
A transmission as claimed in claim 1, characterised by the fact that at least one (4) of said drive shafts (4, 5) is hollow, the other said drive shaft (5) being coaxial and located partially inside the same; said gears comprising a number of gears (R1, R3, R5; R2, R4, R6) fitted on to each said drive shaft (4, 5), and a number of gears (R'1, R'3 R'5; R'2, R'4, R'6) meshing with the same and mounted in idle manner on said output shaft (16) with which they are engaged via sliding couplings (M13, M52, M46) and synchronizing means defining said second clutch means.
Claim 5
Dependent Claim
113 words
A transmission as claimed in claim 3, characterised by the fact that said actuators (A13, A52, A46) comprises a dual-rod piston (23) integral with a respective coupling (M13, M52, M46) in said first stage (2) and sliding inside a cylindrical cavity (24); a pair of bushes (26) sliding in sealed manner between said piston (23) and the inner walls of said cavity (24); and stop means (27) located centrally on said piston (23) and said wall of said cavity (24); said piston (23) and said bushes (26) defining, inside said caviity (24), two opposed chambers (C1, C3; C5, C2; C4, C6) connected to respective on-off solenoid valves (E1, E3; E5, E2; E4, E6).
Claim 6
Dependent Claim
28 words
A transmission as claimed in claim 1, characterised by the fact that said input shaft (12) is driven by a third clutch (13) controlled by a pedal (14).
Claim 7
Dependent Claim
59 words
A transmission as claimed in claim 1, characterised by the fact that it comprises a second stage (3) cascade-connected to said first stage (2) and defining a number of transmission ratios (L, M, V, R) including at least one reverse, and engageable in combination with each said transmission ratio of said first stage (2) via a hand-operated lever (37).
Claim 8
Dependent Claim
36 words
A transmission as claimed in claim 4, characterised by the fact that it comprises means, connected to said control unit (45), for detecting engagement of a transmission ratio in said first and second stages (2, 3).
Claim 9
Dependent Claim
43 words
A transmission as claimed in claim 6, characterised by the fact said control unit (45) comprises processing means for selecting engagement of an appropriate transmission ratio in said first stage (2) subsequent to a change in transmission ratio in said second stage (3).
Claim 10
Dependent Claim
30 words
A transmission as claim 1, characteristed by the fact that it comprises means (P), connected to said control unit (45), for selecting a transmission ratio in said first stage (2).
Claim 11
Dependent Claim
29 words
A transmission as claimed in claim 1, characterised by the fact that it comprises means (48), connected to said control unit (45), for detecting the speed of said vehicle.
Claim 12
Dependent Claim
43 words
A transmission as claimed in claim 1, characterised by the fact that it comprises manual control means (47) connected to said control unit (45) and designed to select engagement of a higher or lower transmission ratio in relation to the one currently engaged.
References Cited (Backward Citations)
US3667309A
Cited
US3863518A
Cited
US4245514A
Cited
FR2474606A2
Cited
US4579015A
Cited
US4565102A
Cited
US4637269A
Cited
US4580459A
Cited
US4560045A
Cited
US4513631A
Cited
US4627312A
Cited
US4726245A
Cited
US4777837A
Cited
DE3527390A1
Cited
DE3618515A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-17 | 1994-03-19 | 1994-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-17 | 1998-03-19 | 1998-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-17 | 2002-03-19 | 2002-09-18 | $7700.00 | Window Closed / Lapsed |