Drive device for vehicle having electric machine and method for operating vehicle

Abstract

The invention relates to a drive device for a vehicle, comprising an electric machine, a two-stage transmission device connected downstream of the electric machine, the electric machine (2) being drivingly connectable to an axle (7) of the vehicle via the transmission device (15), wherein the transmission (15) has an input shaft (9) which is drivingly connected to a rotor shaft of the electric machine and an output shaft (12) which is drivingly connected to an axle (7) of the vehicle, wherein the input shaft (9) can be drivingly connected to the output shaft (12) via a gear wheel (10b) of the first gear or a gear wheel (10a) of the second gear by actuating a first plate clutch (6a) associated with the first gear or a second plate clutch (6b) associated with the second gear, and wherein the transmission (15) implements a braking function, in this way, the first plate clutch (6a) and the second plate clutch (6b) are actuated simultaneously in the transmission (15) so as to be at least partially closed simultaneously.

Description

Technical Field

[0001] The present invention relates to a drive device for a vehicle, the drive device having an electric motor and a two-stage transmission connected downstream of the electric motor.

[0002] The present invention also relates to a method for operating a vehicle. Background Art

[0003] In a passenger car (PKW) according to the prior art, each individual wheel is coupled to its own brake. Thereby, a PKW usually having four wheels has four individual brakes. Here, the braking system and the drive system are systems implemented separately from each other. This applies not only to PKWs driven in a conventional manner, but also to electrically driven PKWs. In an electrically driven PKW, a characteristic is also that, in addition to the wheel brakes, an electric motor in generator operation can contribute a significant and highly variable braking torque depending on the situation.

[0004] In the current braking systems in PKWs, dry-running disc brakes or drum brakes are usually installed. In addition to the continuous maintenance and service costs due to wear and corrosion, the disc brakes or drum brakes are also significantly responsible for the particulate emissions that have been regulated since EURO 7. Additionally, in addition to the torque vector unit, modern drive systems also have load-switchable multi-gear shifting devices, however, the multi-gear shifting devices are not used to implement a braking function.

[0005] DE10 2021 205 073A1 shows a passenger car with an electric rear-wheel drive, the passenger car having a drive system and a braking system, the drive system including a power electronics device, an electric motor, a transmission, and a differential that together form an electric axle, and two side shafts connected to the differential, at the free ends of which rear wheels are respectively arranged. By the braking system having a central brake operatively arranged in the electric axle between the electric motor and the differential, an electrically driven PKW is provided, in which the electric motor acts on the rear axle, and the PKW has a simplified braking system at the driven rear axle.

[0006] AT 520 430A1 shows a brake pad system for a vehicle drive shaft. The differential function is shown by one drive device on each wheel side. Thereby, it is feasible to brake or block the drive side for braking. The braking power can be distributed between the devices on the drive side and the devices on the wheel side. The devices on the wheel side preferably operate in a slip to ensure individual control of the wheels.

[0007] The object of the present invention is to provide an improved drive system having an improved integrated braking function and torque distribution. Summary of the Invention

[0008] The object is achieved by a drive device for a vehicle, which has an electric motor and a two-stage transmission connected downstream of the electric motor, wherein the electric motor can be drivingly connected via the transmission to an axle of a motor vehicle, wherein the transmission has an input shaft drivingly connected to the rotor shaft of the electric motor and an output shaft drivingly connected to the axle of the motor vehicle, wherein the input shaft can be drivingly connected to the output shaft via a first gear or a second gear by actuating a first plate clutch associated with the first gear or a second plate clutch associated with the second gear, and wherein the transmission implements a braking function, wherein the braking function can be activated such that the first plate clutch and the second plate clutch are actuated simultaneously, thereby closing at least partially simultaneously.

[0009] The output of the transmission is connected to the vehicle axle via drive wheels, wherein the axle is disconnected with respect to the left and right wheels and can be connected via a plate clutch each.

[0010] The transmission is load-switchable.

[0011] The plate clutches are actuated via an electric actuator.

[0012] The object is also achieved by a method for operating a motor vehicle with an electric motor and a two-stage transmission connected downstream of the electric motor, wherein the transmission is load-switchable and has two gears and two plate clutches for actuating the two gears, and wherein, in order to enhance the braking effect of the vehicle, in addition to actuating the plate clutches on the axle, the two plate clutches on the driven shaft are also actuated simultaneously in order to generate a braking function by tensioning the two-stage transmission.

[0013] A maintenance-free wet-running braking system integrated in an electric drive is obtained by the solution according to the invention, which is integrated with torque distribution and load-switchable two-gear shifting due to its structural form that meets the loss power requirements for electric vehicles. In addition to the braking torque of the electric motor, the drive system generates an additional braking torque by tensioning the load-switchable multi-gear shifting device. Description of the Drawings

[0014] Figure 1 Shows an embodiment of an electric drive device according to the invention. Detailed Description

[0015] Figure 1 Shows an electric drive device 1 for a motor vehicle, wherein only the wheels, namely the left wheel 3a and the right wheel 3b, are shown. The wheels are placed on separate axles 7, wherein the axle sections 7a and 7b can be connected to the drive wheels 8 via plate clutches 5a and 5b.

[0016] The electric motor 2 with its inverter 4 is mounted such that the drive shaft of the electric motor 2 extends parallel to the vehicle axle 7 in continuation of the rotor shaft serving as the input shaft 9. On the drive shaft 9 of the transmission 15 of the electric motor 2, gear wheels 10a, 10b for the first and second gears are mounted. The gear wheels 10a and 10b engage with their corresponding gear wheels 11a and 11b, which are designed as freewheeling gears arranged on the driven shaft 12. The freewheeling gears 11a and 11b are actuated via plate clutches 6a and 6b respectively. The driven shaft 12 carries a gear 13 that meshes with the drive wheels 8 of the vehicle axle 7.

[0017] Consequently, the described embodiment shows a two-stage transmission 15, by means of which the electric motor 2 can be drivingly connected to the vehicle axle 7.

[0018] The transmission is switched without load in such a way that the plate clutches 6a and 6b are closed and opened in a smooth transition.

[0019] The torque of the electric motor 2 is then transmitted to the drive wheels 8 and the vehicle axle 7 via the engaged gear. Then, the two plate clutches 5a and 5b represent a differential function and the torque can be distributed by appropriate actuation.

[0020] To brake the drive system, the two plate clutches 5a and 5b on the vehicle axle 7 are closed in order to connect the wheels to the electric motor. The electric motor 2 recovers and generates braking torque in this way. The two plate clutches 6a and 6b are closed together partially in order to tension the transmission 15. A further braking torque is achieved via the tensioning.

Claims

1. A drive device (1) for a vehicle, the drive device having an electric motor (2) and a two-stage transmission (15) connected downstream of the electric motor (2), wherein the electric motor (2) can be drivingly connected to an axle (7) of the vehicle via the transmission (15). The transmission (15) has an input shaft (9) drivingly connected to the rotor shaft of the electric motor and an output shaft (12) drivingly connected to the axle (7) of the vehicle. The input shaft (9) can be drivingly connected to the output shaft (12) via a gear (10b) of a first gear or a gear (10a) of a second gear by operating a first plate clutch (6a) associated with the first gear or a second plate clutch (6b) associated with the second gear. And the transmission (15) implements a braking function, and the braking function can be activated such that the first plate clutch (6a) and the second plate clutch (6b) are simultaneously operated in the transmission (15), so as to be at least partially closed simultaneously.

2. The drive device (1) according to claim 1, characterized in that, The output end of the transmission (15) is connected to the axle (7) of the vehicle via a drive wheel (8), wherein the axle (7) is disconnected with respect to a left wheel (3a) and a right wheel (3b) and can be connected via a plate clutch (5a, 5b) respectively.

3. The drive device according to claim 1 or 2, characterized in that, The transmission is load-switchable.

4. The drive device according to any one of the above claims, characterized in that, For the braking process, the plate clutches (5a and 5b) on the axle are closed.

5. The drive device according to any one of the above claims, characterized in that, The plate clutches (6a, 6b, 5a, 5b) are operated via an electric actuator.

6. A method for operating a vehicle by means of a drive device according to any one of claims 1 to 5, the drive device having an electric motor (2) and a two-stage transmission (15) connected downstream of the electric motor (2), the transmission being load-switchable and having two gears and two plate clutches (6a, 6b) for operating the two gears. In order to enhance the braking effect of the vehicle, in addition to operating the plate clutches (6a, 6b) on the axle (7), the two plate clutches (6a, 6b) on the driven shaft (12) are also simultaneously operated, so as to generate an additional braking function by tensioning the two-stage transmission (15).

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