Powertrain of a purely electric all-wheel drive vehicle

Abstract

Drive train (1) of a purely electric all-wheel drive motor vehicle, comprising a first axle (2) and a second axle as well as two electric motors (10) arranged in the direction of travel (3) of the motor vehicle, wherein the first axis (2) can be driven by means of the electric machines (10) via a gearbox (11), wherein the transmission (11) and the first axle (2) are connected to each other by means of at least one bevel gear (20, 7; 20, 27), wherein the gearbox (11) and a shaft for driving the second axle are connected to each other by means of at least one further toothing (22, 23; 22, 28; 22, 21), wherein the transmission (11), except for the output gear (20) of the transmission (11) which is designed as a bevel gear, is designed as a spur gear transmission.

Description

[0001] The invention relates to a drive train of a purely electrically all-wheel drive motor vehicle, having a first and a second axle and two electric motors arranged in the direction of travel of the motor vehicle, wherein the first axle can be driven by means of the electric motors via a transmission.

[0002] DE 600 13 340 T2 discloses such a drivetrain, which is used for an electrically powered earthmoving vehicle or for a four-wheel-drive agricultural vehicle. This drivetrain has two electric motors arranged above one of the rear axles in the direction of travel and interacting with a spur gear located in front of the rear axle. The gear is connected via one or two shafts to the differentials assigned to the two axles, thus the rear axle and the front axle.

[0003] US 6 886 647 B1 discloses a drive train of an electrically driven passenger vehicle, having a first axle and a second axle and two electric machines, wherein the first axle can be driven by means of the electric machines via a transmission, wherein the transmission and the first axle are connected to one another by means of at least one differential, and wherein the transmission and a shaft for driving the second axle are connected to one another by means of at least one further gearing.

[0004] The object of the present invention is to provide a drive train for a purely electrically operated motor vehicle by means of which an all-wheel drive can be realized using structurally simple means.

[0005] The problem is solved by a drive train which is designed according to the features of patent claim 1.

[0006] The drive train of the purely electric all-wheel drive motor vehicle has a first and a second axle as well as two electric motors arranged in the direction of travel of the motor vehicle. The first axle can be driven by the electric motors via a transmission. It is important that the transmission and the first axle are connected to one another by at least one bevel gear, and that the transmission and a shaft for driving the second axle are connected to one another by at least one further gear. The at least one bevel gear thus serves to transfer the torque of the electric motors arranged in the direction of travel to the first axle arranged transversely to the direction of travel. In addition to this first axle, the transmission also drives the shaft, which is in particular a cardan shaft or propshaft, whereby this shaft is connected to the second axle of the vehicle in order to drive it as well.

[0007] According to patent claim 1, the transmission in the drive train is designed as a spur gear, except for the output gear of the transmission designed as a bevel gear or the output gears of the transmission designed as bevel gears.

[0008] Due to this design, the drive train can be very compact in the area of ​​the first axle and the electric motors as well as the transmission located in between.

[0009] The drive train is preferably used in a motor vehicle designed as a passenger car. This passenger car is, in particular, a sports car. This motor vehicle, in particular the passenger car or sports car, is preferably designed as a rear-wheel drive. The electric motors are thus arranged in the rear region of the motor vehicle or the drive train. The electric motors are thus located near the first, rear axle. In particular, it is provided that this axle is located in front of the electric motors.

[0010] In principle, however, the vehicle can be designed as a front-wheel drive. In this case, the electric motors are located in the area of ​​the second, front axle of the drivetrain, specifically in front of this axle.

[0011] The wheels assigned to the drivetrain are connected to it individually via drive shafts. In this case, the drivetrain does not have rigid axles.

[0012] It is considered particularly advantageous if both electric machines are connected to each other via a constant gear ratio.

[0013] According to an advantageous variant, it is provided that a shaft of the transmission can be driven by means of the two electric machines, and a bevel gear toothing has a pinion and a ring gear, wherein the pinion is connected to this transmission shaft and a differential of the first axle can be driven by means of the ring gear.

[0014] Preferably, the drive train is a drive train of a passenger car, wherein a shaft of the transmission can be driven by means of the two electric machines, wherein a spur gear connected to this transmission shaft meshes with a spur gear connected to another shaft of the transmission, wherein this other transmission shaft is connected to the shaft for driving the second axle. In particular, both electric machines are connected to one another via a constant gear ratio and jointly drive the pinion, which drives the differential of the first axle via the ring gear. By means of a gear, in particular a spur gear on the pinion shaft, the shaft, which is in particular designed as a cardan shaft, is then driven via a gear, in particular a spur gear.

[0015] Preferably, the transmission has two output shafts, each output shaft being drivable by one of the electric motors, and each output shaft being connected to a common differential via a respective gear, the output of the differential being connected to the shaft for driving the second axle. In this variant, two bevel gears are provided, each having a pinion and a ring gear, each pinion being connected to one of the two output shafts, and the ring gear being connected to a respective half of the first axle.

[0016] The transmission can thus have two separate pinions, which drive the left and right axle halves of the first axle, respectively, via a respective ring gear, thus driving the left and right wheels of the first axle. Both pinion shafts are connected to a common differential via a respective gear, for transmitting torque to the shaft, in particular the cardan shaft, which is connected to the second axle.

[0017] According to a preferred development of the invention, it is provided that in the drive train both electric machines are synchronous machines or asynchronous machines, or one electric machine is a synchronous machine and the other electric machine is an asynchronous machine. When the vehicle is in operation, one electric machine can be switched off. In particular, an asynchronous machine is switched off because it can then continue to run without magnetic resistance. It is therefore not necessary to uncouple this electric machine. In principle, however, an electric machine designed as a synchronous machine can also be switched off. When one electric machine is switched off, the drive train is supplied with power by the other electric machine, thus driving the wheels of the rear and front axles via this one operating electric machine.

[0018] Further features of the invention will become apparent from the dependent claims, the accompanying drawings, and the description of the preferred embodiments shown in the drawings, without being limited to them. It shows: Fig. 1 a schematic diagram of a first embodiment of the drive train according to the invention, Fig. 2 a schematic diagram of a second embodiment of the drive train according to the invention,

[0019] The embodiment according to the Fig. Figure 1 illustrates a drive train for a purely electrically powered motor vehicle, which is in particular a passenger car, specifically a sports car. Fig. 1 only the area of ​​the drive train assigned to the rear axle of the motor vehicle.

[0020] The drive train 1 with independent wheel suspension has the first, rear axle 2 and a second, front axle (not shown). Relative to the forward direction of travel 3 of the motor vehicle, hereinafter referred to as the direction of travel, the rear axle 2 has a left axle section 4 and a right axle section 5. The two axle sections 4 and 5 are driven by a differential 6 of the rear axle 2. The differential 6 has a ring gear 7. Reference numeral 8 designates the left and right wheels of the rear axle 2, and reference numeral 9 designates bearings for the axle sections 4 and 5 of the rear axle 2. The axle sections 4 and 5 of the rear axle 2 and also the axle sections of the front axle have drive shafts.

[0021] The rear axle 2 is driven by two electric motors 10 via a transmission 11. The transmission 11 is arranged behind the rear axle 2, and the two electric motors 10 are arranged behind the transmission 11. The electric motors 10 are each arranged in the direction of travel 3, and the rotational axis of the respective electric motor 10, represented by its output shaft 12, is thus arranged in the direction of travel 3.

[0022] The stator of the respective electric machine 10 is designated by reference numeral 13, and the rotor of the respective electric machine 10, to which the output shaft 12 is connected, is designated by reference numeral 14. The respective output shaft 12 is mounted in bearings 15.

[0023] The transmission 11 is essentially designed as a spur gear transmission. A pinion 16 designed as a spur gear is connected in a rotationally fixed manner to the respective output shaft 12. The pinions 16 assigned to the two output shafts 12 of the electric motors 10 mesh with a common spur gear 17 of the transmission 1, which is connected to a shaft 18. This shaft 18 is mounted in bearings 19. A pinion 20 designed as a bevel gear is connected to the front end of the shaft 18 extending in the direction of travel 3. This pinion meshes with the ring gear 7 and thus forms a bevel gear with it. The pinion 20 can therefore be driven via the electric motors 10 and, via this, the ring gear 7, the latter driving the differential 6 of the rear axle 2, which drives the two rear wheels 8 via the axle sections 4 and 5.

[0024] Between the spur gear 17 and the pinion 20, the shaft 18 of the transmission 1 is connected to a further spur gear 22. This meshes with a spur gear 23 of the transmission 11, which is connected to a shaft 24, the end of which facing away from the spur gear 23 serves as a connection for a shaft (not shown), in particular a cardan shaft. The torque of the two electric motors 10 is connected to the front axle of the drive train via this cardan shaft, which extends from the area of ​​the rear axle 2 forward into the area of ​​the front axle of the drive train. This connection between the connection point 25 of the shaft 24 and the front axle can be made in a manner generally known from the prior art, whereby a controllable clutch, in particular a hang-on clutch, can certainly be assigned to the shaft or cardan shaft.

[0025] The embodiment according to the Fig. Figure 1 thus illustrates the design of the drive train 1 of a purely electric all-wheel drive motor vehicle, in which both electric motors 10 are connected to each other via a constant gear ratio and jointly drive the pinion 20, which drives the differential 6 of the rear axle 2 via the ring gear 7. By means of the gear 22 on the pinion shaft 18, the (cardan) shaft and thus the front axle are driven via the gear 23.

[0026] In the embodiment of the drive train 1 according to the Fig. 2 are components which in their structure or function are similar to those of the embodiment according to the Fig. 1, are designated by the same reference numerals for the sake of simplicity.

[0027] The drive train 1 according to the embodiment according to the Fig. 2 differs from the drive train 1 according to the embodiment according to Fig. 1 essentially in that in the embodiment according to Fig. 2 two shafts 18 are provided which are arranged parallel and in the direction of travel 3 of the motor vehicle. Each shaft 18 has the spur gear 17, the spur gear 22 and the pinion 20. Accordingly, one electric machine 10 drives one shaft 18 via the pinion 16 assigned to it and the other electric machine 10 drives the other shaft 18 via the pinion 16 assigned to it. If the speed of the electric machines is the same, one shaft 18 is driven at the same speed as the other shaft 18. The pinion 20 of the respective shaft 18 meshes with a ring gear 27 which is connected to the left axle section 4 or the right axle section 5. With this design of the drive train, the rear wheels 8 are driven individually and, consequently, electrical torque vectoring is possible due to different torques of the electric machines 10.

[0028] In order to connect the two electric machines 10 in a force-locking manner to the front axle of the drive train 1 (not shown), the two spur gears 22 of the two shafts 18, which are each arranged between the spur gear 17 and the pinion 20, mesh with spur gears 21 and 28 of a planetary differential 29, wherein an output of the differential 29, illustrated by the connection point 25, is connected to a shaft (not shown), in particular a cardan shaft, and is driven via the front axle of the drive train 1.

[0029] According to this embodiment, the transmission 1 thus has two separate pinions 20, which drive the left and right wheels 8 of the rear axle 2 via a respective ring gear 27. Both pinion shafts 18 are connected to a common differential 29 via a respective gear 22, for introducing torque into the (cardan) shaft.

[0030] In the two electric machines 10 of the embodiment according to the Fig. 1, one electric machine 10 can be a synchronous machine and the other electric machine 10 an asynchronous machine. The asynchronous machine is particularly suitable for operating the vehicle with only one electric machine 10, with the other electric machine 10, the synchronous machine, switched off. It can run without magnetic resistance.

Claims

[1] Drive train (1) of a purely electrically all-wheel drive motor vehicle, with a first axle (2) and a second axle and two electric machines (10) arranged in the direction of travel (3) of the motor vehicle, wherein the first axle (2) can be driven by means of the electric machines (10) via a gear (11), wherein the gear (11) and the first axle (2) are connected to one another by means of at least one bevel gear (20, 7; 20, 27), wherein the gear (11) and a shaft for driving the second axle are connected to one another by means of at least one further toothing (22, 23; 22, 28; 22, 21), wherein the gear (11), except for the output gear (20) of the gear (11) which is designed as a bevel gear, is designed as a spur gear. [2] Drive train (1) according to claim 1, characterized bythat the first axle (2) is a rear axle of the motor vehicle, wherein the electric machines (10) are arranged behind the rear axle (2). [3] Drive train (1) according to claim 1 or 2, characterized by that this is a drive train of a passenger car. [4] Drive train (1) according to one of claims 1 to 3, characterized by that the electric machines (10) are connected to one another via a constant gear ratio or a manual transmission. [5] Drive train (1) according to one of claims 1 to 4, characterized by that a shaft (18) of the transmission (11) can be driven by means of the two electric machines (10), and a bevel gear toothing (20, 7) has a pinion (20) and a ring gear (7), wherein the pinion (20) is connected to this transmission shaft (18) and a differential (6) of the first axle (2) can be driven by means of the ring gear (7). [6] Drive train (1) according to one of claims 1 to 5, characterized bythat a shaft (18) of the transmission (11) can be driven by means of the two electric machines (10), wherein a spur gear (22) connected to this transmission shaft (18) meshes with a spur gear (23) which is connected to another shaft (24) of the transmission (11), wherein this other transmission shaft (24) is connected to the shaft for driving the second axle. [7] Drive train (1) according to one of claims 1 to 4, characterized by in that the transmission (11) has two output shafts (18), each output shaft (18) being drivable by means of one of the electric machines (10), and each output shaft (18) being connected to a common differential (29) via a respective gearwheel (22), the output of the differential (29) being connected to the shaft for driving the second axle. [8] Drive train (1) according to claim 7, characterized bytwo bevel gear teeth (20, 27), each having a pinion (20) and a ring gear (27), wherein the respective pinion (20) is connected to one of the two output shafts (18), and the respective ring gear (27) is connected to the respective axle section (4 or 5) of the first axle (2). [9] Drive train (1) according to one of claims 1 to 8, characterized by that the shaft for driving the second axle is designed as a cardan shaft.

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