Drive axle of an electrically powered motor vehicle

Abstract

The invention relates to a drive axle (1) of an electrically powered motor vehicle, wherein the drive axle (1) has a drive train assembly (2) with a first drive train (3) and a second drive train (4), wherein each drive train (3; 4) is designed as an individual wheel drive and comprises an electric machine (5; 7) and a transmission (6; 8) with at least two transmission stages (9, 10). According to the invention, the drive trains (3, 4) can be coupled to their output shaft assemblies (35, 36) forming an output by means of a transverse lock (32), wherein the transverse lock (32) has a coupling arrangement (33) with a coupling actuating device (34) which is designed to bring about a force flow (F) that closes within one of the two output shaft assemblies (35, 36).

Description

[0001] The invention relates to a drive axle of an electrically operated motor vehicle according to the preamble of patent claim 1.

[0002] Drive axles of electrically powered motor vehicles are well known and can also be referred to as wheel-specific drives, since the drive axle, which is designed to drive a first wheel and a second wheel, has two separate drive trains, each for one of the wheels. The drive trains can be axially parallel or coaxial. The drive trains generally provide a functionally independent drive for each wheel, so that wheel torques, drive power, and speeds can be set or controlled individually for each wheel.

[0003] Typically, in such drive systems, an additional power and wheel torque requirement that goes beyond pure longitudinal performance, as is the case, for example, when using torque vectoring, where, for example, the wheels on the outside of a curve are subjected to higher torques, can only be realized if torque and power reserves have been taken into account in a corresponding design of electric motors, pulse inverters and transmissions.

[0004] The document CN 1 05 459 781 A discloses two independent wheel drives, each with an electric motor and a transmission, wherein transmission output shafts of the independent wheel drives can be coupled to one another by a clutch arrangement.

[0005] From the document DE 10 2009 013 875 B4 a drive axle of an electric vehicle is known, wherein the drive axle has two independent wheel drives, each with an electric motor and a transmission, and wherein the two gear wheels of the transmissions of the independent wheel drives forming the output are supported axially on one another and have helical teeth in opposite directions to one another.

[0006] The document DE 10 2011 076 279 A1 discloses two independent wheel drives, each with an electric motor and a transmission, wherein the transmission output shafts of the individual drives can be coupled to one another by means of a clutch arrangement, wherein the clutch arrangement can be designed as a claw clutch or as a slip clutch.

[0007] The document DE 10 2018 221 601 A1 discloses two independent wheel drives, each with an electric motor and a multi-speed manual transmission, wherein transmission output shafts of the individual drives can be coupled to one another by an electrically controllable multi-plate clutch.

[0008] The document DE 102 48 173 A1 discloses two independent wheel drives, each with an electric motor and a transmission, whereby the transmission output shafts or the transmission input shafts of the individual drives can be coupled to one another by means of a multi-disk clutch or a claw clutch.

[0009] The document JP 2017-178 010 A also discloses two independent wheel drives, each with an electric motor and a multi-speed manual transmission, wherein the transmission output shafts of the individual drives can be coupled to one another by a clutch.

[0010] From the document US 2013 / 0 030 636 A1, two individual wheel drives are known, each with an electric machine and a transmission, wherein the electric machine drives a drive shaft connected to a respective vehicle wheel via the respective transmission, and wherein the drive shafts can be coupled to one another via a clutch.

[0011] From the documents US 2021 / 0 379 977 A1 and US 2021 / 0 381 587 A1, two individual wheel drives are known, each with an electric motor and a transmission, wherein transmission output shafts of the individual drives can be coupled to one another by a clutch, and wherein the clutch is partially integrated in a gear of a transmission output shaft.

[0012] The document DE 10 2017 204 485 A1 discloses a transfer case for distributing a drive torque of a drive unit to a first and a second axle of a motor vehicle, wherein a clutch is arranged coaxially with an input shaft of the transfer case.

[0013] The document WO 2016 / 041 788 A1 discloses an actuator system for a clutch, wherein a servo motor of the actuator system has a ball ramp device.

[0014] Document DE 10 2020 113 192 A1 discloses a drive axle of an electrically operated motor vehicle, wherein the drive axle comprises a drivetrain group with a first drivetrain and a second drivetrain. Each drivetrain is designed as an independent wheel drive and has an electric motor and a transmission. Output shafts are designed such that one of the output shafts is at least partially received in the other of the output shafts.

[0015] It would be advantageous to connect the two drive trains for power and torque distribution, at least partially and / or temporarily, so that a correspondingly required power and torque flow can be realized, wherein a power flow acting on the transmission is designed in the form of a closed power flow, in particular reliably.

[0016] The object of the present invention is therefore to provide an improved drive axle of an electrically operated motor vehicle.

[0017] This object is achieved according to the invention with a drive axle of an electrically operated motor vehicle having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the respective subclaims.

[0018] A drive axle according to the invention of an electrically operated motor vehicle has a drive train group with a first drive train and a second drive train, wherein each drive train is designed as an independent wheel drive and has an electric machine and a transmission with at least two gear stages. According to the invention, the drive trains can be coupled at their output shaft assemblies forming an output by means of a differential lock, wherein the differential lock comprises a clutch arrangement with a clutch actuation device which is designed to bring about a power flow that closes within one of the two output shaft assemblies, and wherein the transmissions are designed in the form of a gear transmission, wherein a clutch of the clutch arrangement is received in a gear of the transmission.

[0019] The advantage of the drive axle according to the invention is that, thanks to the closed power flow to only one of the two drive shaft assemblies, a secure connection between the two drive trains is realized, which can also be quickly released as needed without causing a force influence, in particular a negative force influence, on the remaining components of the drive train assembly. Thus, for example, a drive train assembly with axial force compensation can be used, whereby the axial force compensation remains unaffected by the coupling via the differential lock. Thus, the efficiency advantages of such drive train assemblies can be maintained.

[0020] A further advantage of this drive axle according to the invention is that, due to the concentration of the power flow on the output shaft assemblies and in particular on only one of the two output shaft assemblies, other components of the two drive trains are not exposed to any additional loads when power and torque are distributed with the aid of the differential lock.

[0021] A further advantage is the high rigidity of the drive train group that can be achieved, which can lead to preferable load-bearing capacity and acoustics for gear transmissions in the form of gear drives, since tilting of gears and rotational path deviations can be effectively avoided.

[0022] A further advantage is a space-optimized drive axle with further assurance of axial force compensation through the closed power flow, since the clutch of the clutch arrangement is accommodated in one of the gears.

[0023] In a preferred embodiment of the drive axle according to the invention, the clutch actuating device is designed in the form of a ball ramp actuating device, which can ensure an axial force flow and thus the possible axial force compensation.

[0024] Tilting can be further prevented by designing an output shaft of one of the two output shaft assemblies to at least partially accommodate an output shaft of the other of the two output shaft assemblies. This allows for a bearing concept that minimizes gear tilting.

[0025] A drive train group with axial force compensation can be realized if the gears of the transmissions formed on the respective output shaft assembly are axially supported on one another and are designed with helical teeth opposing one another.

[0026] A multi-plate clutch is particularly advantageous for effective power transmission.

[0027] A preferred embodiment of the drive axle according to the invention is realized if the clutch actuation device is connected to an actuator, in particular by means of an additional gear. The advantage is a reliably controllable and thus regulated differential lock. A simple and cost-effective solution for this is provided by an actuator designed as a servomotor.

[0028] With the drive axle according to the invention, torque and power can be transferred safely and quickly from one individual wheel drive to, in particular, a wheel of the other individual wheel drive, whereby this is possible in motor and / or generator operation of the drive trains.

[0029] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. Identical or functionally equivalent elements are assigned identical reference numerals. They show: Fig. 1 shows a side view of a drive axle of an electrically operated motor vehicle according to the prior art, Fig. 2 in a side view of a drive axle according to the invention of the electrically operated motor vehicle with a drive train group with a differential lock, Fig. 3 in a longitudinal section output shaft assemblies of the drive axle according to the invention. Fig. 2, Fig. 4 in a perspective view the output shaft assemblies of the drive axle according to the invention. Fig. 3, and Fig. 5 in a longitudinal section a receiving output shaft assembly of the drive axle according to the invention with a clutch arrangement.

[0030] A drive axle 1 of an electrically operated motor vehicle according to the prior art is as in Fig. 1. The drive axle 1 has a drive train group 2, which is formed from a first drive train 3 and a second drive train 4. Each drive train 3; 4 is designed as an individual wheel drive and can be operated independently, thus independently of the adjacent drive train 4; 3. For this purpose, the first drive train 3 has a first electric machine 5 and a first transmission 6. The second drive train 4 has a second electric machine 7 and a second transmission 8.

[0031] Each of the transmissions 6, 8 has two gear stages, a first gear stage 9 and a second gear stage 10, wherein the transmissions 6, 8 are designed as gear drives. The first transmission 6 has a first gear pair 11 to form its first gear stage 9, comprising a first gear 12 with a first input shaft 13 and a second gear 14 on a first intermediate shaft 15. Furthermore, the first transmission 6 has a second gear pair 16 to form its second gear stage 10, comprising a third gear 17 on the first intermediate shaft 15 and a fourth gear 18 with a first output shaft 19.

[0032] The second transmission 8 is designed in a virtually identical manner, but mirrored along an extension axis E of the drive train group 2. Thus, to form its first gear stage 9, the second transmission 8 has a third gear pair 20 comprising a fifth gear 21 with a second input shaft 22 and a sixth gear 23 on a second intermediate shaft 24. Furthermore, to form its second gear stage 10, the second transmission 8 has a fourth gear pair 25 comprising a seventh gear 26 on the second intermediate shaft 24 and an eighth gear 27 with a second output shaft 28. The fourth gear 18 with its first output shaft 19 is referred to as the first output shaft assembly 35, and the eighth gear 27 with the second output shaft 28 is referred to as the second output shaft assembly 36. The transmissions 6, 8 could also have more than two gear stages 9, 10.

[0033] The first drive shaft 13 and the second drive shaft 22 are coaxial and have a common first bearing arrangement 29. Likewise, the first intermediate shaft 15 and the second intermediate shaft 24 are coaxial and have a common second bearing arrangement 30. Furthermore, the first output shaft 19 and the second output shaft 28 are also coaxial and have a common third bearing arrangement 31. The bearing arrangements 29, 30, 31, in particular the third bearing arrangement 31, have rolling bearings, in particular in the form of an angular contact roller bearing.

[0034] In Fig. Figure 2 illustrates the drive axle 1 according to the invention with its drive train assembly 2. The two drive trains 3, 4, each designed as an independent wheel drive, can be coupled at their second gear stage 10, which has the first output shaft 19 of the first drive train 3 and the second output shaft 28 of the second drive train 4, by means of a differential lock 32. In other words, the first output shaft assembly 35 can be rotationally connected to the second output shaft assembly 36 by means of the differential lock 32 for transmitting torque.

[0035] The transverse lock 32 has a clutch arrangement 33 with a clutch actuating device 34, which is designed to bring about a force flow F closing within one of the two output shaft assemblies 35, 36, which in Fig. 3 is illustrated with the aid of directional arrows. In the present exemplary embodiment, this is preferably the second output shaft assembly 36, on the side of which an actuator 37 of the clutch arrangement 33 is formed for actuating the clutch actuation device 34. The force flow F is formed exclusively between the clutch arrangement 33, the clutch actuation device 34, and the second output shaft assembly 35. Thus, the second output shaft assembly 36, which is at least partially accommodated in the first output shaft assembly 35, is designed to bring about the closing force flow F.

[0036] The force flow F closing within one of the two output shaft assemblies 35, 36, in the present embodiment the second output shaft assembly 36, can be advantageously brought about if the gears 18, 27 of the output shaft assemblies 35, 36, but in particular all gears 12, 14, 17, 18, 21, 23, 26, 27 of the gears 6, 8 are axially supported on one another and are formed with oppositely helical teeth, as shown in Fig. 2 is illustrated in principle by means of a line formed obliquely to the extension axis E.

[0037] The clutch actuation device 34 is designed as a ball-ramp actuation device, which is configured to bring about the closed power flow F acting on the second output shaft assembly 36. The clutch actuation device 34 is controlled by the actuator 37, which is designed as a servomotor. A further transmission 38 is formed between the actuator 37 and the clutch actuation device 34 for improved control of the clutch actuation device 34. The further transmission 38 is also designed as a gear transmission. It could also be designed as a belt transmission or in a different form.

[0038] The differential lock 32 has the clutch arrangement 33 with a clutch 39 in the form of a multi-disk clutch, wherein an outer disk carrier 40 of the clutch 39 of the second output shaft 28 and an inner disk carrier 41 of the clutch 39 of the first output shaft 19 is assigned.

[0039] The first output shaft 19 is designed to at least partially accommodate the second output shaft 28. In other words, this means that the output shaft 19; 28 of one of the two output shaft assemblies 35, 36 is designed to at least partially accommodate the output shaft 28; 19 of the other of the two output shaft assemblies 36, 35. For this purpose, the first output shaft 19, on which the fourth gear 18 is mounted in a rotationally fixed manner with the first output shaft 19, is at least partially hollow, but in the present embodiment, completely hollow. On its inner surface 42, it has inner bearings 43, preferably in the form of needle bearings, for further mounting of the second output shaft 28 so that, when the differential lock 32 is open, it can rotate relative to the first output shaft 19 about a common longitudinal axis 44. Another form of inner bearing 43 would also be conceivable, for example, plain bearings.

[0040] The second output shaft 28, which is partially accommodated in the first output shaft 19, is also hollow, thus allowing fluid to flow through it. The clutch 39 is accommodated in the eighth gear 27, thus in a receiving opening 45 formed in the eighth gear 27 between a circumferential surface of the eighth gear 27 and the second output shaft 28.

[0041] The clutch actuation device 34, which is designed in the form of a ball ramp actuation device, comprises a first annular disc 46, which has at least partially teeth on its outer circumference for engagement of the further gear 38, and a second annular disc 47 arranged opposite the first annular disc 46 in the form of a thrust ring, wherein balls 48 of the ball ramp actuation device 34 are arranged between the first annular disc 46 and the second annular disc 47. The second annular disc 47 is secured by means of a securing device 49 in the form of a groove 50 formed in the second annular disc 47, as shown in Fig. 4 is visible, and a holding element (not shown in detail) which can be received in the groove 50 to prevent rotation about the longitudinal axis 44.

[0042] The second annular disc 47 is further configured as the raceway of an axial needle bearing 62, which is arranged between the second annular disc 47 and a thrust ring 51. The thrust ring 51 has thrust pins 52 extending in the axial direction, which are configured to contact the clutch 39 for force transmission. The thrust ring 51 has the thrust pins 52 arranged at regular intervals around its circumference for uniform force transmission. It is also configured as the raceway of the axial needle bearing 62.

[0043] When the clutch actuation device 34 is actuated, the pressure ring 51 is moved axially, toward the clutch 39, so that the pressure pins 52 can transmit force to the clutch 39. In the present example, the clutch 39 is designed in the form of a multi-plate clutch and has a first pressure plate 57 arranged opposite the pressure ring 51 for applying force to the pressure pins 52. Between the first pressure plate 57 and a second pressure plate 58 of the multi-plate clutch 39, plates 59 of the outer plate carrier 40 and plates 59 of the inner plate carrier 41 are arranged, preferably alternatingly, to transmit force. To axially secure the clutch 39, a securing element 60 in the form of a snap ring is arranged on the second pressure plate 58, facing away from the plates 59.

[0044] For lubrication and cooling of the inner bearings 43 and the differential lock 32, the first output shaft 19 has a through-opening 53 at its end region 54 facing away from the second output shaft 28. Lubricant, which also serves as a coolant, can flow through this through-opening 53 into the hollow first output shaft 19 and the hollow second output shaft 28, and be guided via the inner bearings 43 and through a flow channel 55 formed in and penetrating the second output shaft 28 to the clutch 39. Thus, the differential lock 32, the first output shaft assembly 35, and the second output shaft assembly 36 can be advantageously lubricated and cooled.

[0045] The clutch actuation device 34 is axially secured to the first annular disc 46 by means of an abutment 56 in the form of a fixed-fit ball bearing on the second output shaft 28. To open the differential lock 32 and to adjust it, a spring element 61 in the form of a spring washer is arranged between the eighth gear 27 and the thrust ring 51.

[0046] The shafts 13, 15, 19 of the gear stages 9, 10 of the first drive train 3 are preferably designed such that they are each designed to receive the coaxially formed shaft 22; 24; 28 of the second drive train 4. List of reference symbols 1 drive axle 2 Drivetrain group 3 First drive train 4 Second drive train 5 First electric machine 6 First gearbox 7 Second electric machine 8 Second gearbox 9 First gear stage 10 Second gear stage 11 First gear pair 12 First gear 13 First drive shaft 14 Second gear 15 First intermediate shaft 16 Second gear pair 17 Third gear 18 Fourth gear 19 First output shaft 20 Third gear pair 21 Fifth gear 22 Second drive shaft 23 Sixth gear 24 Second intermediate shaft 25 Fourth gear pair 26 Seventh gear 27 Eighth gear 28 Second output shaft 29 First bearing arrangement 30 Second bearing arrangement 31 Third bearing arrangement 32 transverse lock 33 Coupling arrangement 34 Clutch operating device 35 First output shaft assembly 36 Second output shaft assembly 37 Actuator 38 Additional gearbox 39 Clutch 40 outer disc carriers 41 inner disc carrier 42 inner surface 43 bottom brackets 44 Longitudinal axis 45 receiving opening 46 First ring disc 47 Second ring disc 48 ball 49 Safety device 50 grooves 51 Pressure ring 52 pressure bolts 53 Passage opening 54 End area 55 Flow channel 56 abutments 57 First pressure disc 58 Second thrust washer 59 slats 60 securing element 61 spring element 62 axial needle bearings E extension axis F Power flow

Claims

[1] Drive axle (1) of an electrically operated motor vehicle, wherein the drive axle (1) has a drive train group (2) with a first drive train (3) and a second drive train (4), wherein each drive train (3; 4) is designed as an independent wheel drive and comprises an electric machine (5; 7) and a transmission (6; 8) with at least two transmission stages (9, 10), characterized byin that the drive trains (3, 4) can be coupled at their output shaft assemblies (35, 36) forming an output by means of a transverse lock (32), wherein the transverse lock (32) has a clutch arrangement (33) with a clutch actuating device (34) which is designed to bring about a force flow (F) closing within one of the two output shaft assemblies (35, 36), and wherein the transmissions (6, 8) are designed in the form of a gear transmission, wherein a clutch (39) of the clutch arrangement (33) is received in a gear (18; 27) of the transmission (6; 8). [2] Drive axle (1) according to claim 1, characterized by that the clutch actuating device (34) is designed in the form of a ball ramp actuating device. [3] Drive axle (1) according to claim 1 or 2, characterized bythat an output shaft (19; 28) of one of the two output shaft assemblies (35, 36) is designed to at least partially receive an output shaft (28; 19) of the other of the two output shaft assemblies (36, 35). [4] Drive axle (1) according to claim 3, characterized by that the output shaft assembly (35; 36), which is at least partially accommodated, is designed to bring about the closing force flow (F). [5] Drive axle (1) according to one of the preceding claims, characterized by that gear wheels (18, 27) of the transmissions (6, 8) formed on the respective output shaft assembly (35, 36) are axially supported on one another and are formed with helical teeth opposite one another. [6] Drive axle (1) according to one of the preceding claims, characterized by that the clutch (39) is a multi-plate clutch. [7] Drive axle (1) according to one of the preceding claims, characterized bythat the clutch actuating device (34) is connected to an actuator (37) by means of a further gear (38). [8] Drive axle (1) according to claim 7, characterized by that the actuator (37) is a servo motor. [9] Drive axle (1) according to claim 7 or 8, characterized by that the further transmission (38) is a gear transmission. [10] Drive axle (1) according to one of the preceding claims, characterized by that shafts (13; 15; 19; 22; 24; 28) of the gear stages (9, 10) of one drive train (3; 4) are designed to receive a coaxially formed shaft (22; 24; 28; 13; 15; 19) of the other drive train (4; 3). [11] Drive axle (1) according to one of the preceding claims, characterized by that the gear stages (9, 10) of the gears (6, 8) each have a common bearing arrangement (29, 30, 31).

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