Claims
- 1. A drive device for one of a mobile excavator vehicle, a wheeled loader vehicle and a similar work vehicle, comprising:
- a prime mover (3) driving a transmission (4) designed as power-shiftable planetary transmission having at least first and second shiftable gears;
- the first and second shiftable gears of said transmission (4) being alternatively engageable and disengageable via first and second friction clutches (12, 13);
- gear-shift valve means (23) connected to supply pressurized oil to said first and second friction clutches (12, 13) for controlling engagement and disengagement of said first and second friction clutches (12, 13);
- said first and said second friction clutches (12, 13) being spring-accumulator clutches and being disengaged by oil pressure supplied by at least one oil pump (21) via an oil pressure line (22) and said gear shift valve means (23); and
- at least said second friction clutch (13), and having a static leakage-oil-free oil supply;
- wherein pressure control means (39, 45, 47) is provided for sensing the oil pressure in said oil pressure line (22) and controlling operation of said gear shift valve means (23), and when said pressure control means senses that the oil pressure generated by said at least one oil pump (21) falls below a first specific value, said pressure control means causes said gear-shift valve means (23) to adjust to a position in which said second friction clutch (13) is disengaged by the pressurized oil.
- 2. A drive device for one of a mobile excavator vehicle, a wheeled loader vehicle and a similar work vehicle, comprising:
- a prime mover (3) driving a transmission (4) designed as power-shiftable planetary transmission having at least first and second shiftable gears;
- the first and second shiftable gears of said transmission (4) being alternatively engageable and disengageable via first and second friction clutches (12, 13);
- gear-shift valve means (23) connected to supply pressurized oil to said first and second friction clutches (12, 13) for controlling engagement and disengagement of said first and second friction clutches (12, 13);
- said first and said second friction clutches (12, 13) being spring-accumulator clutches and being disengaged by oil pressure applied by at least one oil pump (21) via an oil pressure line (22) and said gear shift valve means (23);
- one of said friction clutches (12) being supplied with pressurized oil via a rotary input shaft (6) of the transmission (4); and
- at least said second friction clutch (13), having a static leakage-oil-free oil supply;
- wherein pressure control means (39, 45, 47) is provided for sensing the oil pressure in said oil pressure line (22) and controlling operation of said gear shift valve means (23), and when said pressure control means senses that the oil pressure generated by said at least one oil pump (21) falls below a first specific value, said pressure control means causes said gear-shift valve means (23) to adjust to a position in which said second friction clutch (13) is disengaged by the pressurized oil and said first friction clutch (12) is engaged whereby one of the shiftable gears of said transmission (4) is engaged to facilitate further travel of the vehicle incorporating the drive device.
- 3. A drive device according to claim 1, wherein said pressure control means comprises a first pressure switch (45) attached to said oil pressure line (22), leading from said at least one oil pump (21) to said gear-shift valve means (23), for sensing the pressure in said oil pressure line (22), and when said first pressure switch (45) senses that the oil pressure falls below the first specific value, said pressure control means causes aid gear-shift valve means (23) to shifted to the position in which said second friction clutch (13) is disengaged by the pressurized oil.
- 4. A drive device according to claim 2, wherein a hydraulic accumulator (44) is attached to said oil pressure line (22).
- 5. A drive device according to claim 1, wherein said gear-shift valve means (23) includes at least one compression spring (51) and, in case of failure of an electric control current supplied by said pressure control means, said gear shift valve means is shifted, via said at least one compression spring, (51) to the position in which said second friction clutch (13) is disengaged by the pressurized oil.
- 6. A drive device according to claim 1, wherein a handbrake valve (46) is situated in said oil pressure line (22) leading from said at least one oil pump (21) to said gear-shift valve means by which the supply of pressurized oil to said first and second friction clutches (12, 13) can be regulated, and
- said pressure control means further comprises a pressure switch (47) attached to said oil pressure line (22) between said hand-brake valve (46) and said gear-shift valve means (23) and when said pressure switch (47) senses that the oil pressure falls below a second specific value, lower than the first specific value, said pressure control means controls a steering valve to disengage said prime mover (3) from drive.
- 7. A drive device according to claim 6, wherein said prime mover is a hydraulic motor (3) supplied with pressurized oil by a hydraulic pump (35) via said steering valve (38), and, when the oil pressure falls below said second specific value, said steering valve (38) is adjusted to a neutral shift position which shuts off oil communication between said hydraulic pump (35) and said hydraulic motor (3).
- 8. A drive device according to claim 6, wherein said prime mover is a hydraulic motor (3) supplied with pressurized oil by a hydraulic pump (35) and, when the oil pressure falls below said second specific value, said steering control means is adjusted to a neutral position so that said hydraulic motor cooperates in braking the vehicle.
- 9. A drive device according to claim 6, wherein said prime mover is a hydraulic motor (3) which is supplied with pressurized oil by a hydraulic pump (35) via said steering valve (38), and
- said gear-shift valve means (23) is divided into separate shift valves.
- 10. A drive device according to claim 9, wherein each one of said separate gear-shift valve controls one of said first and second friction clutches (12, 13) and, in case of failure of an electric control current of said pressure control means, said gear-shift valves are adjusted by springs force to engage only one of said first and second friction clutches.
- 11. A drive device for one of a mobile excavator, a wheeled loader and a similar work vehicle, comprising:
- a prime mover (3) driving a transmission (4) designed as power-shiftable planetary transmission having at least first and second shiftable gears;
- the first and second shiftable gears of said transmission (4) being alternatively engageable and disengageable via first and second friction clutches (12, 13);
- gear-shift valve means (23) connected to supply pressurized oil to said first and second friction clutches (12, 13) for controlling engagement and disengagement of said first and second friction clutches (12, 13);
- said first and second friction clutches (12, 13) being spring-accumulator clutches and being disengaged by oil pressure supplied by at least one oil pump (21) via an oil pressure line (22) and said gear shift valve means (23);
- one of said friction clutches (12) being supplied with pressurized oil via a rotary input shaft (6) of the transmission (4); and
- at least said second friction clutch (13), having a static leakage-oil-free oil supply;
- wherein pressure control means (39, 45, 47) is provided for sensing the oil pressure in said oil pressure line (22) and controlling operation of said gear shift valve means (23), and when said pressure control means senses that the oil pressure generated by said at least one oil pump (21) falls below a first specific value, said pressure control means causes said gear-shift valve means (23) to adjust to a position in which said second friction clutch (13) is disengaged by the pressurized oil;
- said gear-shift valve means (23) is divided into separate shift valves, and each one of said separate gear-shift valve controls one of said first and second friction clutches (12, 13) and, in case of failure of an electric control current from said pressure control means, said gear-shift valves are adjusted by springs force to neutral positions in which both of said first and second friction clutches are disengaged.
- 12. The drive device according to claim 1, wherein in the event of a failure of an electrical control current supplied by said pressure control means to said gear shift valve, said gear shift valve means is adjusted by a biasing mechanism to disengage at least one of said first and second clutches to facilitate further travel of the vehicle.
- 13. The drive device according to claim 2, wherein in the event of a failure of an electrical control current supplied by said pressure control means to said gear shift valve, said gear shift valve means is adjusted by a biasing mechanism to disengage at least one of said first and second clutches to facilitate further travel of the vehicle.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3911333 |
Apr 1989 |
DEX |
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Parent Case Info
This is a continuation of copending application Ser. No. 07/761,745 filed on Sep. 12, 1991 now abandoned.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/EP90/00512 |
3/31/1990 |
|
|
9/12/1991 |
9/12/1991 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO90/12227 |
10/18/1990 |
|
|
US Referenced Citations (5)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2110320 |
Jun 1983 |
GBX |
2164397 |
Mar 1986 |
GBX |
8401419 |
Apr 1984 |
WOX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
761745 |
Sep 1991 |
|