ELECTRIC VEHICLE TRANSMISSION

Abstract

Disclosed is an electric vehicle transmission (6″) comprising a drive input shaft (11), a drive output shaft (13), a first planetary gearset (15), and a second planetary gearset (16). The drive input shaft (11) is provided for connection to an electric machine (7), where each of the first planetary gearset (15) and the second planetary gearset (16) includes a first element (17, 18), a second element (19, 20) and a third element (21, 22), respectively. A first shifting element (A) and a second shifting element (B′) are provided, by the selective actuation of which the drive input shaft (11) can be connected to the drive output shaft (13) by means of the planetary gearsets (15, 16) by engaging a gear. Also disclosed is a drive module (2″) with such an electric vehicle transmission (6″) and a method for operating an electric vehicle transmission (6″).

Claims

1-12. (canceled)

13. Electric vehicle transmission (6 to 6.sup.VII), comprising: a drive input shaft (11), the drive input shaft (11) configured for connection to an electric machine (7); a drive output shaft (13); a first planetary gearset (15) and a second planetary gearset (16), wherein the first planetary gearset (15) and the second planetary gearset (16) each comprise a first element (17, 18), a second element (19, 20), and a third element (21, 22), respectively, in the form of a sun gear, a planetary web, and a ring gear, in each case; and wherein a first shifting element (A; A′) and a second shifting element (B; B′) are provided, by the selective actuation of which the drive input shaft (11) can be coupled to the drive output shaft (13) by way of the planetary gearsets (15, 16) with the engagement of a gear in each case; wherein: the first element (17) of the first planetary gearset (15) is connected rotationally fixed to the drive input shaft (11); the second element (19) of the first planetary gearset (15) is connected rotationally fixed to the first element (18) of the second planetary gearset (16); the second element (20) of the second planetary gearset (16) is connected rotationally fixed to the drive output shaft (13); the third element (22) of the second planetary gearset (16) is held fixed; the third element (21) of the first planetary gearset (15) can be connected rotationally fixed to the drive output shaft (13) by means of the first shifting element (A), or the third element (21) of the first planetary gearset (15) can be held fixed by means of the first shifting element (A′); and two of the elements (17, 19, 21) of the first planetary gearset (15) can be brought into rotationally fixed connection with one another by means of the second shifting element (B; B′).

14. The electric vehicle transmission (6 to 6.sup.VII) according to claim 13, wherein in its actuated condition the second shifting element (B; B′) connects the first element (17) in a rotationally fixed manner to the third element (21) of the first planetary gearset (15) or connects the second element (19) in a rotationally fixed manner to the third element (21) of the, first planetary gearset (15), or connects the first element (17) in a rotationally fixed manner to the second element (19) of the first planetary gearset (15).

15. The electric vehicle transmission (6 to 6.sup.VII) according to claim 13, wherein the first shifting element (A; A′) is in the form of an interlocking shifting element and the second shifting element (B′) is a frictional shifting element.

16. The electric vehicle transmission (6 to 6.sup.VII) according to claim 15, wherein the first shifting element (A; A′) is a claw-type shifting element, and the second shifting element (B′) is a disk clutch.

17. The electric vehicle transmission (6 to 6.sup.VII) according to claim 13, wherein a first gear (G1) between the drive input shaft (11) and the drive output shaft (13) is obtained by closing the first shifting element (A; A′) and a second gear (G2) between the drive input shaft (11) and the drive output shaft (13) is obtained by actuating the second shifting element (B; B′).

18. The electric vehicle transmission (6 to 6.sup.VII) according to claim 13, further comprising a connection point (12) in the drive input shaft (11) axially between the first planetary gearset (15) and the second planetary gearset (16), the connection point (12) configured to connect the drive input shaft (11) to the electric machine (7).

19. The electric vehicle transmission (6 to 6.sup.VII) according to claim 13, further comprising a connection point (14) in the drive output shaft (13) axially on a side of the second planetary gearset (16) that faces away from the first planetary gearset (15), the connection point configured to connect the drive output shaft (13) to the electric vehicle transmission (6 to 6.sup.VII).

20. A drive module (2 to 2.sup.VII) for an electric vehicle, comprising an electric machine (7) with a rotor; and an electric vehicle transmission (6 to 6.sup.VII) according to claim 13, wherein a rotor (10) of the electric machine (7) is connected rotationally fixed to the drive input shaft (11) of the electric vehicle transmission (6 to 6.sup.VII).

21. The drive module (2 to 2.sup.VII) according to claim 20, wherein the electric machine (7) is arranged coaxially with the first planetary gearset (15) and the second planetary gearset (16) of the electric vehicle transmission (6 to 6.sup.VII).

22. The drive module (2 to 2.sup.VII) according to claim 21, wherein the rotor (10) of the electric machine (7) is fixedly connected to the drive input shaft (11).

23. The drive module (2 to 2.sup.VII) according to claim 22, wherein the electric machine (7) is positioned axially overlapping the two planetary gearsets (15, 16), and the two planetary gearsets (15, 16) are arranged radially inside the electric machine (7).

24. An electric vehicle comprising at least one drive module (2 to 2.sup.VII) according to claim 20.

25. The electric vehicle of claim 24, wherein the electric vehicle is selected from a bus or a truck.

26. A method for operating an electric vehicle transmission (6 to 6.sup.VII) according to claim 13, the method comprising: closing the second shifting element (B′) with slip; actuating the first shifting element (A; A′); and changing between the first gear (G1) and the second gear (G2) under load, wherein closing the second shifting element (B′) overlaps with actuating the first shifting element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Advantageous embodiments of the invention, which are explained in what follows, are illustrated in the drawings, which show:

[0035] FIG. 1: A schematic view of a motor vehicle drive-train of an electric vehicle;

[0036] FIGS. 2 to 9: In each case, a schematic view of a drive module of the motor vehicle drive-train shown in FIG. 1, each corresponding to an embodiment of the invention; and

[0037] FIG. 10: An example of a shifting scheme of element vehicle transmissions of the drive module shown in FIGS. 2 to 9.

DETAILED DESCRIPTION

[0038] FIG. 1 shows a schematic representation of a motor vehicle drive-train 1 of an electric vehicle, which is preferably a truck or a bus. In the motor vehicle drive-train 1 a drive module 2 is provided, downstream from the drive output side of which a differential gear system 3 is connected. By way of the differential gear system 3 drive power is distributed to drive wheels 4 and 5 of a drive axle of the electric vehicle. As can be seen in FIG. 1, the drive module 2 and the differential gear system 3 are aligned in the travel direction of the electric vehicle.

[0039] FIG. 2 shows a schematic representation of the drive module 2 of the motor vehicle drive-train 1 in FIG. 1, wherein the drive module 2 is designed in accordance with a first possible embodiment of the invention. In this case the drive module 2 consists of an electric vehicle transmission 6 and an electric machine 7, which are accommodated together in a housing 8 of the drive module 2. The electric machine 7 comprises a stator 9 and a rotor 10 positioned radially inside the stator 9. In this case the stator 9 is connected rotationally fixed to the housing 8 of the drive module 2.

[0040] The rotor 10 is connected rotationally fixed to a drive input shaft 11 of the electric vehicle transmission 6, this connection being in the form of a solid connection between the rotor 10 and a first connection point 12 of the drive input shaft 11 so that the rotor 10 and the drive input shaft 11 always rotate with the same rotation speed. The electric machine 7 and the drive input shaft 11 are arranged coaxially with one another. Also positioned coaxially with the electric machine 7 and the drive input shaft 11 is a drive output shaft 13 of the electric vehicle transmission 6, and the drive output shaft 13 is connected at a connection point 14 such that the electric vehicle transmission 6 is connected to the downstream differential gear system 3 in FIG. 1.

[0041] The electric vehicle transmission 6 also comprises a first planetary gearset 15 and a second planetary gearset 16, each consisting of a first respective element 17 or 18, a second respective element 19 or 20 and a third respective element 21 or 22. In the individual planetary gearset 15 or 16, in this case the first element 17 or 18 is a respective sun gear, the second element 19 or 20 is a respective planetary web, and the third element 21 or 22 is a respective ring gear. The planetary webs in each case carry a plurality of planetary gearwheels, which specifically mesh both with the sun gear and with the ring gear concerned. Accordingly, the two planetary gearsets 15 and 16 are minus planetary gearsets.

[0042] As can be seen in FIG. 2, the first element of the first planetary gearset 15 is connected permanently and rotationally fixed to the drive input shaft 11, which correspondingly connects the first element 17 of the first planetary gearset 15 rotationally fixed to the rotor 10 of the electric machine 7. In addition, the second element 19 of the first planetary gearset 15 and the first element 18 of the second planetary gearset 16 are permanently connected and rotationally fixed to one another, that connection being made in this case by way of a shaft 23. Accordingly, the second element 19 of the first planetary gearset 15, the shaft 23 and the first element 18 of the second planetary gearset 16 always rotate with the same rotation speed.

[0043] The third element 22 of the second planetary gearset 16 is permanently held fixed, in that the third element 22 is always connected rotationally fixed to the housing 8 of the drive module 2. Moreover, the second element 20 of the second planetary gearset 16 is permanently connected rotationally fixed to the drive output shaft 13, so that the said second element 20 of the second planetary gearset 16 rotates together with the drive output shaft 13.

[0044] The electric vehicle transmission 6 also comprises two shifting elements A and B, which are in the form of interlocking shifting elements and specifically unsynchronized claw-type clutches. In this case the two shifting elements A and B are combined in a shifting device 24 and have a common actuating device 25 by means of which, from a neutral position, either the shifting element A or the shifting element B can be changed to a respective actuated position. In the actuated condition the shifting element A connects the third element 21 of the first planetary gearset 15 rotationally fixed to the drive output shaft 13 so that the third element 21 of the first planetary gearset 15 is also connected rotationally fixed to the second element 20 of the second planetary gearset 16.

[0045] In contrast, in its actuated condition the shifting element B forms a rotationally fixed connection of the third element 21 of the first planetary gearset 15 to the shaft 23, which also means a rotationally fixed connection between the third element 21 of the first planetary gearset 15 and the second element 19 of the first planetary gearset 15. The result is that actuation of the shifting element B blocks the first planetary gearset 15.

[0046] In this case the drive output shaft 13 is essentially in the form of a solid shaft, whereas both the drive input shaft 11 and the shaft 23 are hollow shafts, each axially overlapping the radially inside drive output shaft 13 and surrounding the latter radially. The connection point 12 of the drive input shaft 11 is located axially between the first planetary gearset 15 and the second planetary gearset 16, so that in this area, the rotationally fixed connection to the rotor 10 of the electric machine 7 is also formed. In this case the electric machine 7 is positioned axially overlapping the two planetary gearsets 15 and 16, and the two planetary gearsets 15 and 16 are located radially inside the electric machine 7.

[0047] The shifting device 24 with the two shifting elements A and B is arranged axially on a side of the first planetary gearset 15 facing away from the second planetary gearset 16, so that the shifting device 24 is preferably located radially in the area of the third element 21 of the first planetary gearset 15. Finally, the connection point 14 of the drive output shaft 13 is formed axially on a side of the second planetary gearset 16 facing away from the first planetary gearset 15.

[0048] FIG. 3 shows a schematic representation of a drive module 2′ which can also be used in the motor vehicle drive-train 1 of FIG. 1. Here, this drive module 2′ is designed in accordance with a second possible embodiment of the invention, and therefore corresponds essentially to the previous variant shown in FIG. 2. The difference is, however, that in an electric vehicle transmission 6′ of the drive module 2′, when actuated a shifting element A′ connects the third element 21 of the first planetary gearset 15 fast to the housing 8 of the drive module 8 so that rotation of the said third element 21 of the first planetary gearset 15 is prevented. Correspondingly, the drive output shaft 13 is now connected only to the second element 20 of the second planetary gearset 16, whereas owing to the now no longer necessary ability to he coupled to the third element 21 of the first planetary gearset 15, the drive output shaft 13 can be made as an axially short solid shaft. In other respects, the possible embodiment according to FIG. 3 corresponds to the variant shown in FIG. 2, so that reference can be made to the description of the latter.

[0049] FIG. 4 shows a schematic view of a drive module 2″ that corresponds to a third embodiment of the invention, such that this embodiment as well can be used in the motor vehicle drive-train 1 according to FIG. 1. Here, this embodiment too corresponds in very large measure to the variant in FIG. 2, with the difference that in an electric vehicle transmission 6″ a shifting element B′ is in this case in the form of a frictional shifting element. Specifically, the shifting element B′ is a disk clutch. A further difference is that in its actuated state the shifting element B′ connects the third element 21 of the first planetary gearset 15 rotationally fixed to the drive input shaft 11, so that correspondingly, when the shifting element B′ is actuated the first element 17 of the first planetary gearset 15 and the third element 21 of the first planetary gearset 15 are brought into rotationally fixed connection with one another. This again results in blocking of the first planetary gearset 15. In this case the shifting element B′ is arranged axially in a plane with the first planetary gearset 15 and radially surrounding it. In contrast, the shifting element shifting element A is now formed as a single shifting element. In other respects, the embodiment according to FIG. 4 corresponds to the variant in FIG. 2, so reference can be made to the description of the latter.

[0050] FIG. 5 shows a schematic view of a drive module 2″′ according to a fourth possible embodiment of the invention. This drive module 2″′ can also be used in the motor vehicle drive-train 1 of FIG. 1 and corresponds in very large measure to the variant in FIG. 2. The difference in this case is that in an electric vehicle transmission 6″′ a shifting element B′, as already in the previous variant according to FIG. 4, is in the form of a frictional shifting element and specifically a disk clutch. As already in the variant according to FIG. 2, in its actuated condition this shifting element B′ connects the third element 21 of the first planetary gearset 15 and the second element 19 of the first planetary gearset 15 rotationally fixed to one another, with the result that the first planetary gearset 15 is blocked. Axially, the shifting element B′ is arranged between the shifting element A made as a single shifting element and the first planetary gearset 15. In other respects, the possible embodiment according to FIG. 5 corresponds to the variant in FIG. 2, so reference can be made to the description of the latter.

[0051] Furthermore, FIG. 6 shows a schematic representation of a drive module 2.sup.IV designed in accordance with a fifth embodiment of the invention, and which can again be used in the motor vehicle drive-train 1 of FIG. 1. In this case the drive module 2.sup.IV corresponds essentially to the embodiment according to FIG. 2. the difference being that in an electric vehicle transmission 6.sup.IV a shifting element B′ is again in the form of a frictional shifting element. Specifically, the shifting element B′ is a disk clutch and in its actuated state connects the drive input shaft 11 rotationally fixed to the shaft 23, which correspondingly results in a rotationally fixed connection between the first element 17 of the first planetary gearset 15 and the second element 19 of the first planetary gearset 15. Accordingly, when the shifting element B′ is actuated the first planetary gearset 15 is blocked. Axially, the shifting element B′ is in this case arranged between the connection point 12 of the drive input shaft 11 and the second planetary gearset 16. In other respects, the embodiment according to FIG. 6 corresponds to the variant in FIG. 2, so reference can be made to the description of the latter.

[0052] Furthermore, FIG. 7 shows a schematic representation of a drive module 2.sup.V which is designed in accordance with a sixth possible embodiment of the invention. Here, this embodiment too can be used in the motor vehicle drive-train 1 of FIG. 1. The drive module 2.sup.V corresponds in very large measure to the variant according to FIG. 3, with the difference that in an electric vehicle transmission 6.sup.V a shifting element B′ is again in the form of a frictional shifting element and specifically, a disk clutch. Moreover, in its actuated state the shifting element B′ connects the third element 21 of the first planetary gearset 15 rotationally fixed to the drive input shaft 11, which also results in a rotationally fixed connection between the first element 17 of the first planetary gearset 15 and the third element 21 of the first planetary gearset 15 and thus blocks the first planetary gearset 15. In this case the shifting element B′ is arranged axially in a plane with the first planetary gearset 15 and radially around it. In contrast, the shifting element A′ is now in the form of a single shifting element. In other respects, the embodiment according to FIG. 7 corresponds to the variant according to FIG. 3, so reference can be made to the description of the latter.

[0053] FIG. 8 shows a schematic view of a drive module 2.sup.VI according to a seventh possible design of the invention. This drive module 2.sup.VI can also be used in the motor vehicle drive-train in FIG. 1 and it corresponds in very large measure to the variant in FIG. 3. The difference here is that is an electric vehicle transmission 6.sup.VI a shifting element B′ is in the form of a frictional shifting element, specifically a disk clutch. In its actuated condition this shifting element B′ connects the third element 21 of the first planetary gearset 15 and the second element 19 of the first planetary gearset 15 rotationally fixed to one another, with the result that the first planetary gearset 15 is blocked. Axially, the shifting element B′ is arranged between the shifting element A′ and the first planetary gearset 15. In other respects, the embodiment according to FIG. 8 corresponds to the variant according to FIG. 3, so reference can be made to the description of the latter.

[0054] Finally, FIG. 9 shows a schematic representation of a drive module 2.sup.VII which is designed in accordance with an eighth embodiment of the invention and can also be used in the motor vehicle drive-train 1 of FIG. 1. This drive module 2.sup.VII corresponds essentially to the embodiment according to FIG. 3, the difference being that in an electric vehicle transmission 6.sup.VII a shifting element B′ is again in the form of a frictional shifting element. The shifting element B′ is in the form of a disk clutch and in its actuated condition it connects the drive input shaft 11 rotationally fixed to the shaft 23, which also results in a rotationally fixed connection between the first element 17 of the first planetary gearset 15 and the second element of the first planetary gearset 15. Thus, when the shifting element B′ is actuated the first planetary gearset 15 is blocked. Axially, the shifting element B′ is arranged between the connection point 12 of the chive input shaft 11 and the second planetary gearset 16. In other respects, the embodiment according to FIG. 9 corresponds to the variant according to FIG. 3, so reference can be made to the description of the latter.

[0055] FIG. 10 shows an example shifting scheme for the electric vehicle transmissions 6 to 6′ with the drive modules 2 to 2′ in FIGS. 2 to 9. As can be seen, in this case two gears G1 and G2 can be obtained. In the columns of the shifting scheme an X indicates which of the shifting elements A or A′ and B or B′ is closed in each case.

[0056] As can be seen in FIG. 10, the first gear G1 is engaged by actuating the shifting element A or A′ and the second gear G2 by closing the shifting element B or B′. In the electric vehicle transmissions 6″ to 6′ a gearshift from the gear G1 to the gear G2 can be carried out under load, since the shifting element B′ is in the form of a frictional shifting element. In the present case that is done by closing the shifting element B′ with slip while the shifting element A or A′ is in its actuated condition, and thereby partially taking up the load by the shifting element B′. When the shifting element A or A′ is then essentially free from load, the shifting element A or A′ is opened and thereafter the shifting element B′ is fully closed.

[0057] In contrast, in the two electric vehicle transmissions 6 and 6′ in FIGS. 2 and 3 gearshifts between the gears G1 and G2 can only be carried out with traction force interruption, since here both of the two shifting elements A or A′ and B are interlocking shifting elements.

[0058] The gears G1 and G2 can each be used for driving the electric vehicle by means of the electric machine 7 when the electric machine 7 is operated as an electric motor. Moreover, in the gears G1 and G2 braking with recuperation can also be carried out in each case by operating the electric machine 7 as a generator.

[0059] By virtue of the designs of an electric vehicle transmission according to the invention, a compact structure can be realized.

INDEXES

[0060] Motor vehicle drive-train

[0061] 2 to 2.sup.VII Drive module

[0062] 3 Differential gear system

[0063] 4 Drive wheel

[0064] 5 Drive wheel

[0065] 6 to 6.sup.VII Electric vehicle transmission

[0066] 7 Electric machine

[0067] 8 Housing

[0068] 9 Stator

[0069] 10 Rotor

[0070] 11 Drive input shaft

[0071] 12 Connection point

[0072] 13 Drive output shaft

[0073] 14 Connection point

[0074] 15 Planetary gearset

[0075] 16 Planetary gearset

[0076] 17 First element

[0077] 18 First element

[0078] 19 Second element

[0079] 20 Second element

[0080] 21 Third element

[0081] 22 Third element

[0082] 23 Shaft

[0083] 24 Shifting device

[0084] 25 Actuating device

[0085] A, A′ Shifting element

[0086] B, B′ Shifting element

[0087] G1 Gear

[0088] G2 Gear