DRIVE ARRANGEMENT FOR A TRACTOR

Abstract

Disclosed is a drive arrangement for a tractor. In one example, the drive arrangement includes a first powertrain, a power take-off for driving a coupled attachment unit, and/or including a pump power take off for driving at least one hydraulic pump. A second powertrain has a vehicle transmission with at least one transmission output for driving at least one vehicle axle. A first electric machine can be coupled in terms of drive to the first powertrain. A second electric machine can be coupled in terms of drive to the second powertrain.

Claims

1-15. (canceled)

16. A drive arrangement (1) for a tractor, comprising: a first powertrain (2) having a power take-off (4) for driving a couplable attachment unit and/or having a pump power take-off (5) for driving at least one hydraulic pump (P1, P2, P3, P4); a second powertrain (3) having a vehicle transmission (G3) with at least one transmission output (8) for driving at least one vehicle axle (7); a first electric machine (EM1) and a second electric machine (EM2); wherein the first electric machine (EM1) is coupled and/or couplable in terms of drive to the first powertrain (2) and the second electric machine (EM2) is coupled and/or couplable in terms of drive to the second powertrain (3).

17. The drive arrangement (1) of claim 16, further comprising an internal combustion engine (VM), wherein at least one of the first and second electric machines (EM1, EM2) cab be operated in a generator mode and is operatively connected to the internal combustion engine (VM) for generating electrical energy.

18. The drive arrangement (1) of claim 17, wherein: the first electric machine (EM1) is configured at least as a generator and the second electric machine (EM2) is configured as an electric motor; the first powertrain (2) can be driven at least by the internal combustion engine (VM) and the second powertrain (3) can be driven by the second electric machine (EM2) configured as an electric motor; and the first electric machine (EM1) is operatively connected to the internal combustion engine (VM) and in a generator mode provides electrical energy for the second electric machine (EM2).

19. The drive arrangement (1) of claim 17, wherein the first electric machine (EM1) is configured as an electric motor and the second electric machine (EM2) is configured at least as a generator; the first powertrain (2) can be driven by the first electric machine (EM1) which is configured as an electric motor; the second powertrain (3) can be driven at least by the internal combustion engine (VM); and the second electric machine (EM2) is operatively connected to the internal combustion engine (VM) and in a generator mode provides electrical energy to the first electric machine (EM2).

20. The drive arrangement (1) of claim 16, wherein each of the first and second electric machines (EM1, EM2) is configured as an electric motor, wherein the first powertrain (2) can be driven by the first electric machine (EM1) and the second powertrain (3) can be driven by the second electric machine (EM2).

21. The drive arrangement (2) of claim 16, further comprising an energy supply unit (6) configured for storing and/or providing electrical energy, wherein the first and the second electric machines (EM1, EM2) are connected in terms of supply technology to the energy supply unit (6).

22. The drive arrangement (2) of claim 16, wherein the first and the second powertrains (2, 3) are separated from one another in terms of gearing.

23. The drive arrangement (2) of claim 16, wherein the first powertrain (2) is connected and/or connectable to the second powertrain (3) in terms of gearing via the vehicle transmission (G3) so that drive torques of the first and the second powertrains (2, 3) can be added together.

24. The drive arrangement (2) of claim 16, wherein the vehicle transmission (G3) comprises: a vehicle transmission input shaft (EW) for forming a transmission drive; a vehicle transmission output shaft (AW) for forming the at least one transmission output (8); a first coupling device (K1) assigned to the vehicle transmission input shaft (EW); and a second coupling device (K2) assigned to the vehicle transmission output shaft (AW); wherein a coupling half of the first coupling device (K1) has a first toothed portion (VA1), the first toothed portion (VA1) connected via at least one gear stage to the vehicle transmission output shaft (AW); and wherein a coupling half of the second coupling device (K2) has a second toothed portion (VA2), the second toothed portion (VA2) connected via at least one further gear stage to the vehicle transmission input shaft (EW).

25. The drive arrangement (1) of claim 24, wherein: the vehicle transmission (G3) has a planetary gear (10) with a sun gear (SR), a ring gear (HR), a planet carrier (PT), and a plurality of planet gears (PR) rotatably mounted on the planet carrier (PT); the sun gear (SR) has a sun gear portion (SA) and a first spur gear portion (SA1), wherein the sun gear portion (SA) is in engagement with the planet gears (PR) for forming a planetary stage; and the first spur gear portion (SA1) is in engagement with the first toothed portion (VA1) of the first coupling device (K1) for forming a first spur gear stage.

26. The drive arrangement (1) of claim 25, wherein: the vehicle transmission (G3) has a first switching element (SE1) and a second switching element (SE2) each movable between a release position and a switching position; the first switching element (SE1) in the switching position couples the planet carrier (PT) fixedly in terms of rotation to the vehicle transmission output shaft (AW) so that in a closed state of the first coupling device (K1) a torque path (M1) runs from the vehicle transmission input shaft (EW) via the planetary stage to the vehicle transmission output shaft (AW); and the second switching element (SE2) in the switching position couples the first spur gear portion (SA1) fixedly in terms of rotation to the vehicle transmission output shaft (AW), so that in a closed state of the first coupling device (K1) a torque path (M1) runs from the vehicle transmission input shaft (EW) via the first spur gear stage to the vehicle transmission output shaft (AW).

27. The drive arrangement (1) of claim 26, wherein: the first powertrain (2) has a gearwheel portion (ZA) and the ring gear (HR) has external toothing; the gearwheel portion (ZA) is in engagement and/or may be brought into engagement with the external toothing of the ring gear (HR) for connecting the first powertrain (2) to the second powertrain (3) in terms of gearing; and in the switching position of the first switching element (SE1) a further torque path (M2) runs from the first powertrain (2) via the gearwheel portion (ZA) to the planetary gear (10).

28. The drive arrangement (1) of claim 25, wherein the vehicle transmission input shaft (EW) has a second spur gear portion (SA2), the second spur gear portion (SA2) in engagement with the second toothed portion (VA2) of the second coupling device (K2) for forming a second spur gear stage, so that in a closed state of the second coupling device (K2) a torque path (M1) runs from the vehicle transmission input shaft (EW) via the second spur gear stage to the vehicle transmission output shaft (AW).

29. The drive arrangement (1) of claim 16, further comprising a transmission output (9) for driving at least one further vehicle axle, wherein the further vehicle axle is connected via a further coupling device (K3) to the further transmission output (9), so that in a closed state of the further coupling device (K3) the further vehicle axle is driven and in an open state of the further coupling device (K3) the further vehicle axle is not driven.

30. The drive arrangement (1) of claim 29, wherein the vehicle transmission output shaft (AW) has a further spur gear portion (SA3) and a coupling half of the further coupling device (K3) has a further toothed portion (VA3), wherein the further spur gear portion (SA3) and the further toothed portion (VA3) are in engagement with one another for forming a further spur gear stage (SA3).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Further features, advantages and effects of the invention emerge from the following description of preferred exemplary embodiments of the invention, in which:

[0038] FIG. 1 shows a schematic view of a drive arrangement for a tractor as an exemplary embodiment of the invention;

[0039] FIGS. 2a and 2b show a schematic view of a vehicle transmission of the drive arrangement of FIG. 1 in two different switching states;

[0040] FIG. 3 shows in the same view as in FIGS. 2a, b the vehicle transmission in a further switching state;

[0041] FIG. 4 shows a schematic view of the drive arrangement as an alternative exemplary embodiment of the invention;

[0042] FIG. 5 shows a schematic view of the vehicle transmission of the drive arrangement of FIG. 2 in a switching state.

DETAILED DESCRIPTION

[0043] FIG. 1 shows in a highly schematic view a drive arrangement 1 for a tractor, not shown, as an exemplary embodiment of the invention. For example, the tractor is configured as an agricultural tractor. The drive arrangement has a first and a second powertrain 2, 3, wherein the first and the second powertrains 2, 3 are separated from one another in terms of gearing.

[0044] Current solutions for electrified drives are only suitable to a limited degree for the different energy supplies on the agricultural tractor, for example for a diesel engine or battery, and are not able to be undertaken without significant adjustments. Additionally, the installation space required by current approaches is significantly higher than in the case of currently used agricultural tractor transmissions, so that an integration of the electrified drive in existing agricultural tractor designs is only possible with great difficulty. Associated with the high requirement for installation space is the high degree of complexity of the powertrain with a plurality of planetary gear sets and switching elements. Approaches via individual wheel drives, for example, require new vehicle designs and are very expensive at the initial stage, since only some of the drives will be designed to be electrified and the majority will remain conventional in the medium term.

[0045] According to the invention a drive arrangement 1 is proposed, said drive arrangement permitting different energy supplies, providing the standard interfaces of the current agricultural tractor transmission and additionally providing the required installation space for the power electronics, for example, without exceeding the current installation space limits of standard transmissions. This drive arrangement 1 is described hereinafter with reference to that of FIG. 1.

[0046] The first powertrain 2 serves for providing energy to different consumers of the tractor. To this end, the first powertrain 2 has a power take-off 4 for driving a working implement which is mechanically couplable or coupled to the tractor or which is stationary, and a pump power take-off 4 for driving a plurality of pumps P1, P2, P3, P4. Additionally, the first powertrain 2 has an internal combustion engine VM, only shown schematically, and a first electric machine EM1 including power electronics, which are operatively connected together via a transmission gear G1. For example, the internal combustion engine VM is configured as a diesel engine and the first electric machine EM1 as a generator and/or as an electric motor. For example, the transmission gear G1 is configured as a spur gear mechanism.

[0047] The transmission gear G1 has a transmission gear input shaft EW1 for connecting the first electric machine, and a further transmission gear input shaft EW2 for connecting the internal combustion engine VM, and a transmission gear output shaft AW1 for forming the power take-off 4 and further transmission gear output shafts AW2, AW3 for forming the pump power take-off 5. The transmission gear G1 has a drive gear AR1 and a further drive gear AR2, wherein the two drive gears AR1, AR2 are in engagement with one another for forming a gear stage. In this case, the drive gear AR1 is connected fixedly in terms of rotation via the transmission gear input shaft EW1 to the first electric machine EM1 and the further drive gear AR2 is connected fixedly in terms of rotation via the further transmission gear input shaft EW2 to the internal combustion engine VM. In particular, the further transmission gear input shaft EW2 and the transmission gear output shaft AW1 form a common shaft, wherein the further drive gear AR2 is arranged fixedly in terms of rotation on the shaft. The further transmission gear input shaft EW2 and the transmission gear output shaft AW1 are thus driven at the same rotational speed.

[0048] In a generator mode of the first electric machine EM1 this is driven via the internal combustion engine VM, wherein a drive torque generated by the internal combustion engine VM is transmitted via the transmission gear stage to the first electric machine EM1. As a result, the first electric machine EM1, which is configured as a generator, is driven and generates electrical energy which is stored in an energy supply unit 6, for example an electrical accumulator.

[0049] Optionally, in a motor mode of the first electric machine EM1 a further output torque may be generated by the first electric machine EM1, wherein the first electric machine EM1, which is configured as an electric motor, is supplied with electrical energy by the energy supply unit 6.

[0050] The internal combustion engine VM and the first electric machine EM1 may in this case act together on the powertrain EM1 so that a parallel hybrid drive is implemented.

[0051] The transmission gear G1 has an output gear BR1 which is in engagement with the further drive gear AR2 via an intermediate gear ZR. The output gear BR1 is arranged fixedly in terms of rotation on the further transmission gear output shaft AW2 and forms therewith a pump power take-off 5, for example, for a main pump P1, a lubrication and/or cooling pump P2 and a steering pump P3. Moreover, the transmission gear G1 has a further output gear BR2 which is in engagement with the drive gear AR1. The further output gear BR2 is arranged fixedly in terms of rotation on the further transmission gear output shaft AW3 and forms therewith a pump power take-off 5, for example, for a constant gear pump P3.

[0052] Moreover, the first powertrain 2 has a further transmission gear G2 for transmitting the output torque acting on the transmission gear output shaft AW1 to the power take-off 4. For example, the further transmission gear G2 is configured as a PTO transmission. The further transmission gear G2 has a drive ring gear AH1 and a further drive ring gear AH2, wherein the transmission gear output shaft AW1 is guided coaxially through the two drive ring gears AH1, AH2. The transmission gear output shaft AW1 in this case is selectively couplable fixedly in terms of rotation via a first coupling element KE1 to one of the two drive ring gears AH1, AH2.

[0053] The two drive ring gears AH1, AH2 are in engagement with an intermediate stepped gear SR1 with different gear ratios. Moreover, the further transmission gear G2 has a further intermediate stepped gear SR2, wherein the stepped gear SR1 is in engagement with the further intermediate stepped gear SR2 via exactly one stage. Additionally, the further transmission gear G2 has an output ring gear BH1 and a further output ring gear BH2, wherein a power take-off shaft NW is guided coaxially through the two output ring gears BH1, BH2 for forming the power take-off 4. The two output ring gears BH1, BH2 in each case are in engagement with the further intermediate stepped gear SR1 with different gear ratios. The power take-off shaft NW is selectively couplable fixedly in terms of rotation to one of the two drive ring gears BH1, BH2 via a second coupling element KE2 so that, depending on the coupling position of the first and the second coupling element KE1, KE2, the output torque is able to be transmitted from the transmission gear output shaft AW1 to the power take-off shaft NW in four different gear stages.

[0054] The second powertrain 3 serves for driving the tractor. To this end, the second powertrain 3 has a driven vehicle axle 7, preferably a rear axle, which is connected in terms of gearing via a vehicle transmission G3 to a second electric machine EM2 including the power electronics. The second electric machine EM2 is configured as an electric motor, wherein the energy supply unit 6 provides electrical energy for the second electric machine EM2.

[0055] The vehicle transmission G3 has a vehicle transmission input shaft EW which is coupled in terms of drive to the second electric machine EM2. For example, the vehicle transmission input shaft EW is configured as a motor shaft of the second electric machine EM2. The vehicle transmission G3 has a vehicle transmission output shaft AW which forms a transmission output 8 for the vehicle axle 7 and a further transmission output 9 for a further vehicle axle, not shown.

[0056] The vehicle transmission G3 is configured as a dual clutch transmission, wherein the vehicle transmission G3 has a first and a second coupling device K1, K2 for coupling the second electric machine EM2 at least to the vehicle axle 7. The two coupling devices K1, K2 are configured in each case as a multiplate clutch, wherein the first coupling device K1 is assigned to the vehicle transmission input shaft EW and the second coupling device K2 is assigned to the vehicle transmission output shaft AW. In this case an external plate carrier of the first coupling device K1 is connected fixedly in terms of rotation to the vehicle transmission input shaft EW and an external plate carrier of the second coupling device K2 is connected fixedly in terms of rotation to the vehicle transmission output shaft AW.

[0057] The vehicle transmission G3 has a planetary gear 10 which has a ring gear HR, a sun gear SR, a planet carrier PT and a plurality of planet gears PR which are rotatably mounted on the planet carrier PT. The planetary gear 10 is arranged coaxially to the vehicle transmission output shaft AW, wherein the sun gear SR is configured as a stepped ring gear and the vehicle transmission output shaft AW is guided through the sun gear SR. The sun gear SR has a sun gear portion SA and a first spur gear portion SA2, wherein for forming a planetary stage the planet gears PR are in engagement, on the one hand, with the ring gear HR which is fixed to the housing and, on the other hand, with the sun gear portion SA. The internal plate carrier of the first coupling device K1 has a first toothed portion VA1 which is in engagement with the first spur gear portion SA1 for forming a first spur gear stage. For example, the first toothed portion VA1 is formed by a spur toothing system arranged on the internal plate carrier of the first coupling device K1.

[0058] The vehicle transmission G3 has a first and a second switching element SE1, SE2, wherein the two switching elements SE1, SE2 are movably arranged on the vehicle transmission output shaft AW, axially between a switching position and a release position, and fixedly in terms of rotation in the direction of rotation. The first switching element SE1 serves for coupling the planet carrier PT fixedly in terms of rotation to the vehicle transmission output shaft AW. The second switching element SE2 serves for coupling the sun gear SR, in particular the first spur gear portion SA1, fixedly in terms of rotation to the vehicle transmission output shaft AW.

[0059] The vehicle transmission input shaft EW has a second spur gear portion SA2 and an inner plate carrier of the second coupling device K2 has a second toothed portion VA2, wherein the second spur gear portion SA2 and the second toothed portion VA2 are in engagement with one another for forming a second spur gear stage. Thus the vehicle transmission G3, which is configured as a dual clutch transmission, has two spur gear stages and a planetary stage with different gear ratios in each case.

[0060] The vehicle transmission output shaft AW is connected in terms of gearing at the point of the transmission output 8 to a differential transmission 11, in particular a rear axle differential, wherein the differential transmission 11 distributes the drive torque of the second electric machine EM2 to two vehicle wheels 12a, b, in particular rear wheels.

[0061] The further vehicle axle is couplable via a further coupling device K3 to the vehicle transmission output shaft AW, in particular for implementing an all-wheel drive. To this end, the further coupling device K3 is configured as a further multiplate clutch. At the point of the further transmission output 9 the vehicle transmission output shaft AW has a further spur gear portion SA3, wherein a coupling half of the further coupling device K3 has a further toothed portion VA3. The further spur gear portion SA3 and the further toothed portion VA3 are in engagement with one another for forming a further spur gear stage.

[0062] FIGS. 2a, b and 3 show in each case a torque path of the first powertrain 3 for different switching states of the vehicle transmission G3. Depending on the switching state of the two switching elements SE1, SE2 and the two coupling devices K1, K2, a total of three different gear stages may be represented with different gear ratios. Optionally a third switching element, not shown, and a third spur gear stage, not shown, may be supplemented by a fourth gear ratio for a fourth gear stage.

[0063] In FIG. 2a the vehicle transmission G3 is switched, for example, into a first gear stage. To this end, the first coupling device K1 is closed and the second coupling device K2 is opened, wherein the first switching element SE1 is arranged in the switching position and the second switching element SE2 is arranged in the release position. In this case, the vehicle transmission input shaft EW is coupled via the first coupling device K1 and the sun gear SR to the planetary gear 10, wherein the planet carrier PT is connected via the first switching element SE1 fixedly in terms of rotation to the vehicle transmission output shaft AW. In an operating state of the second electric machine EM2, therefore, a torque path M1 runs from the vehicle transmission input shaft EW via the first coupling device K1, the first spur gear stage and the planetary stage to the vehicle transmission output shaft AW, wherein the torque path M1 is divided into a first partial torque path TM1 in the direction of the transmission output 8 and into a second partial torque path TM2 in the direction of the further transmission output 9. The second partial torque path TM2 runs in this case via the further spur gear stage to the further coupling device K3, wherein by closing the further coupling device K3 the further vehicle axle may be connected-in for the all-wheel drive.

[0064] In FIG. 2b the vehicle transmission G3 is switched, for example, into a second gear stage. To this end, the first coupling device K1 is opened and the second coupling device K2 is closed, wherein the two switching elements SE1, SE2 are arranged in each case in the release position. In this case, the vehicle transmission output shaft AW is coupled via the second coupling device K2 to the second spur gear portion SA2. In the operating state of the second electric machine EM2, therefore, the torque path M1 runs from the vehicle transmission input shaft EW via the second spur gear stage and the second coupling device K2 to the vehicle transmission output shaft AW, wherein the torque path M1 is subsequently divided into the first and the second partial torque path TM1, TM2, as already described above.

[0065] In FIG. 3 the vehicle transmission G3 is switched, for example, into a third gear stage. To this end, the first coupling device K1 is closed and the second coupling device K2 is opened, wherein the first switching element SE1 is arranged in the release position and the second switching element SE2 is arranged in the switching position. In this case, the vehicle transmission input shaft EW is coupled to the sun gear SR via the first coupling device K1, wherein the first spur gear portion SA1 is connected via the second switching element SE2 fixedly in terms of rotation to the vehicle transmission output shaft AW. In the operating state of the second electric machine EM2, therefore, the torque path M1 runs from the vehicle transmission input shaft EW via the first coupling device K1 and the first spur gear stage to the vehicle transmission output shaft AW, wherein the torque path M1 is subsequently divided into the first and the second partial torque path TM1, TM2, as already described above.

[0066] FIG. 4 shows in a highly schematic view an alternative embodiment of the drive arrangement 1 as has already been described above in FIG. 1. In this case, the drive arrangement 1 differs from the embodiment described in FIG. 1, in that the first and the second powertrains 2, 3 are connected together in terms of gearing. To this end, the ring gear HR is rotatable about the vehicle transmission output shaft AW, wherein the vehicle transmission output shaft AW1 has a gearwheel portion ZA which is in engagement with the ring gear HR. For example, the gearwheel portion ZA is configured as a spur gear which is connected fixedly in terms of rotation to the transmission gear output shaft AW1. The ring gear HR has on its external circumference an external toothing via which the gearwheel portion ZA meshes with the ring gear HR.

[0067] In the first gear stage, the SE1 is in the switching position as shown in FIG. 5, wherein the torque path M1, as already described in FIG. 2a, runs via the planetary gear 10 to the vehicle transmission output shaft AW. Additionally, a further torque path M2 runs from the transmission gear output shaft AW1 via the gearwheel portion ZA to the ring gear HR and thus into the planetary gear 10. In this case the planetary gear 10 serves as a summation gear, wherein the torques of the two torque paths M1, M2 are combined in the planetary gear 10 and transmitted via the switching elements SE1 to the vehicle transmission output shaft AW or divided into the two partial torque paths TM1, TM2. As a result, a power split is implemented in the first gear stage, wherein by combining the drive torques of the first and the second powertrain 2, 3 or the powers of the internal combustion engine VM and/or the first electric machine EM1 and the second electric machine EM2, a greater efficiency may be achieved in the first gear stage.

LIST OF REFERENCE NUMERALS

[0068] 1 Drive arrangement [0069] 2 First powertrain [0070] 3 Second powertrain [0071] 4 Power take-off [0072] 5 Pump power take-off [0073] 6 Energy supply unit [0074] 7 Vehicle axle [0075] 8 Transmission output [0076] 9 Further transmission output [0077] 10 Planetary gear [0078] 11 Differential transmission [0079] 12a, b Vehicle wheels [0080] AH1 Drive ring gear [0081] AH2 Further drive ring gear [0082] AW Vehicle transmission output shaft [0083] AW1 Transmission gear output shaft [0084] AW2 Further transmission gear output shaft [0085] AW3 Further transmission gear output shaft [0086] AR1 Drive gear [0087] AR2 Further drive gear [0088] BH1 Further output ring gear [0089] BH2 Further output ring gear [0090] BR1 Output gear [0091] BR2 Further output gear [0092] EM1 First electric machine [0093] EM2 Second electric machine [0094] EW Vehicle transmission input shaft [0095] EW1 Transmission gear input shaft [0096] EW2 Further transmission gear input shaft [0097] G1 Transmission gear [0098] G2 Further transmission gear [0099] G3 Vehicle transmission [0100] HR Ring gear [0101] K1 First coupling device [0102] K2 Second coupling device [0103] K3 Further coupling device [0104] KE1 First coupling element [0105] KE2 Second coupling element [0106] M1 Torque path [0107] M2 Further torque path [0108] NW Power take-off shaft [0109] P1 Main pump [0110] P2 Lubrication/cooling pump [0111] P3 Steering pump [0112] P4 Gear pump [0113] PR Planet gears [0114] PT Planet carrier [0115] SA Sun gear portion [0116] SA1 First spur gear portion [0117] SA2 Second spur gear portion [0118] SA3 Further spur gear portion [0119] SR Sun gear [0120] SR1 Stepped ring gear [0121] SR2 Further stepped ring gear [0122] TM1 First partial torque path [0123] TM2 Second partial torque path [0124] VA1 First toothed portion [0125] VA2 Second toothed portion [0126] VA3 Further toothed portion [0127] VM Internal combustion engine [0128] ZR Intermediate gear [0129] ZA Gearwheel portion