DRIVE UNIT HAVING AN ELECTRIC MOTOR

Abstract

A drive unit for a vehicle, having an electric motor and a transmission unit, wherein the electric motor is connected to the transmission unit via a drive shaft and at least one first output shaft can be driven to rotate by the transmission unit, wherein the drive unit also has at least one brake unit. The rotation of the at least one output shaft can be delayed by the brake unit, wherein the drive unit has at least one of the following: a lubricant circuit through which both the transmission unit and at least one brake unit can be supplied with lubricant, and a cooling circuit through which both (i) at least one of the electric motor and a power electronics system assigned to the electric motor; and (ii) at least one brake assembly can be supplied with coolant.

Claims

1. A drive unit for a vehicle, having an electric motor and a transmission unit, wherein the electric motor is connected to the transmission unit via a drive shaft and at least one first output shaft can be driven to rotate by the transmission unit, wherein the drive unit also has at least one brake unit, wherein the rotation of the at least one output shaft can be delayed by the brake unit, characterized in that the drive unit has at least one of the following: a) a lubricant circuit through which both the transmission unit and at least one brake unit can be supplied with lubricant, and b) a cooling circuit through which both (i) at least one of the electric motor and a power electronics system assigned to the electric motor; and (ii) at least one brake assembly can be supplied with coolant.

2. The drive unit as claimed in claim 1, wherein at least one brake unit comprises a wet-running brake.

3. The drive unit as claimed in claim 2, wherein the wet-running brake is a multiple disk brake.

4. The drive unit as claimed in claim 1, wherein the transmission unit and the brake unit are arranged in a common housing, and the electric motor is also one of: arranged in the common housing and on the common housing.

5. (canceled)

6. (canceled)

7. The drive unit as claimed in claim 1, wherein the lubricant circuit is an oil circuit.

8. The drive unit as claimed in claim 1, wherein the cooling circuit is a water-based cooling circuit.

9. The drive unit as claimed in claim 1, wherein two output shafts can be driven to rotate by the transmission unit, wherein two brake units are provided, wherein the rotation of an output shaft can be delayed by a respective brake unit.

10. The drive unit as claimed in claim 1, wherein the transmission unit has a differential for driving two output shafts, wherein furthermore a first distance between the differential and a first brake unit, which acts on the first output shaft, and a second distance between the differential and a second brake unit, which acts on the second output shaft is substantially the same.

11. The drive unit as claimed in claim 1, wherein the transmission unit has a differential for driving two output shafts, wherein furthermore a first distance between the differential and a first brake unit, which acts on the first output shaft, and a second distance between the differential and a second brake unit, which acts on the second output shaft, is different.

12. The drive unit as claimed in claim 4, wherein the common housing is designed as an aluminum die-cast component.

13. The drive unit as claimed in claim 1m where the lubricant circuit and/or cooling circuit have/has an electronic controller or electronic regulator for the purpose of power adaptation.

14. The drive unit as claimed in claim 13, wherein one of the electronic controller and the electronic regulator has one of a pressure control device and pressure regulation device for the purpose of fluid power adaptation.

15. The drive unit as claimed in claim 14, wherein one of the electronic controller and electronic regulator of the two fluid circuits is designed independently and is adjusted in each case in an individually metered manner.

16. The drive unit as claimed in claim 13, wherein the control or regulation of the two fluid circuits is mutually coordinated.

17. The drive unit as claimed in claim 14, wherein one of the pressure control device and the pressure regulation device comprises electrical components such as at least one of: at least one fluid pressure sensor, at least one electrohydraulic valve, an electromotive pump drive motor, and at least one electronic control unit.

18. The drive unit of claim 1, wherein the drive unit drives at least one wheel of an electrically driven vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The embodiments are explained in more detail below with reference to the figures, wherein one or more features of the figures can be a feature of the invention, either alone or in combination. Furthermore, the figures are only to be seen as examples but not restrictive in any way.

[0047] FIG. 1 schematically shows a sectional view through a first refinement of a drive unit;

[0048] FIG. 2 schematically shows a sectional view through a further refinement of a drive unit; and

[0049] FIG. 3 schematically shows a sectional view through a detail of a further refinement of a drive unit.

DETAILED DESCRIPTION

[0050] FIG. 1 shows a refinement of a drive unit 10. The drive unit 10 serves for example to drive an electrically drivable vehicle, such as a purely electric vehicle.

[0051] The drive unit 10 comprises an electric motor 12, which can be assigned a power electronics system 14, for example, and also a transmission unit 16. The transmission unit 16 can have a plurality of transmission stages 18 in order to transmit a rotation of a drive shaft 20, which is connected to the electric motor 12 or is set into rotation by the latter, to at least one, in the present refinement to two, output shafts 24.sub.a, 24.sub.b, for example via a differential 22. The electric motor 12 is thus connected to the transmission unit 16 via the drive shaft 20, and the output shafts 24.sub.a, 24.sub.b can be driven to rotate by the transmission unit 16 and thus the electric motor 12.

[0052] FIG. 1 also shows that the drive unit 10 also has two brake units 26.sub.a, 26.sub.b, which can be designed in principle identically to or differently from each other. In particular, the brake units 26.sub.a, 26.sub.b can be wet-running brakes, wherein multiple disk brakes may be possible. The brake units 26.sub.a, 26.sub.b are arranged in such a way that the rotation of the output shafts 24.sub.a, 24.sub.b can be delayed by the brake units 26.sub.a, 26.sub.b.

[0053] In particular, FIG. 1 shows that the electric motor 12, the transmission unit 16 and the brake units 26.sub.a, 26.sub.b are arranged in a common housing 28. The housing 28 is of multi-part design here and has a large number of housing parts fastened to one another. In detail, the housing parts are connected to one another by screw connections 30.

[0054] The configuration of the housing 28 will be described in more detail below. Firstly, a motor cover unit 32 with bearings 40.sub.a, 40.sub.b, which forms the housing part for the electric motor 12, is provided. Said motor cover unit is connected to the transmission housing part 34, which comprises a first transmission housing half 34.sub.a and a second transmission housing half 34.sub.b. For the brake units 26.sub.a, 26.sub.b there is also provided an integrated first brake housing 36.sub.a and an integrated second brake housing 36.sub.b, which are closed by a first brake housing cover 38.sub.a and a second brake housing cover 38.sub.b.

[0055] Alternatively, as is shown in the enlarged refinement according to FIG. 3, a brake housing part 39 which encloses the second brake unit 26.sub.b can be arranged on the second transmission housing half 34.sub.b. A brake housing cover 38.sub.b may then be omitted. The same is self-evidently possible for the first transmission housing half 34.sub.a, on which a brake housing part 39 can also be arranged.

[0056] The refinement according to FIG. 3 allows an axial installation space that can be changed, for example by an adaptable number of brake disks of a multiple disk brake, to be realized for example by brake housing parts 39 of different sizes. Therefore, the braking torque that can be achieved can be changed by the number of brake disks. Different disk thicknesses also enable adaptation to thermal requirements. However, this results in the need for a variable axial installation space.

[0057] Bearings 40.sub.a, 40.sub.b, 40.sub.c, 40.sub.d, 40.sub.e are also provided for guiding the output shafts 24.sub.a, 24.sub.b from the interior of the housing 28 to the exterior of the housing 28 and also for supporting the output shafts 24.sub.a, 24.sub.b.

FIG. 1 also shows that the drive unit 10 has a lubricant circuit 42, such as an oil circuit, through which both the transmission unit 16 and the brake units 26.sub.a, 26.sub.b can be supplied with lubricant, such as oil. Correspondingly, for example, oil conveyed to the transmission stages 18 can also be conveyed in the direction of the arrow to the brake units 26.sub.a, 26.sub.b or can be conveyed away from them. The refinement according to FIG. 1 has lubricant lines 44, such as oil lines, since the brake unit 26.sub.a is not arranged directly at the volume 46 of the transmission stages 18. This is due to the fact that, according to the refinement of FIG. 1, a first distance D.sub.1 between the differential 22 and the first brake unit 26.sub.a and a second distance D.sub.2 between the differential 22 and the second brake unit 26.sub.b differs, wherein the distance D.sub.1 is for example greater than the distance D.sub.2, or basically also vice versa. In FIG. 1, the distance D.sub.1 is selected in such a way that the first brake unit 26.sub.a is still located below the electric motor 12. If the distance D.sub.1 is selected to be greater, for example, the electric motor 12 can be located between the brake units 26.sub.a, 26.sub.b, as a result of which the first output shaft 24.sub.a can be placed closer to the electric motor 12. This enables a reduced radial space requirement, i.e. at right angles to the first output shaft 24.sub.a and thus approximately at right angles to a vehicle axis.

[0058] Furthermore, in the refinement according to FIG. 1, the braking torque to be transmitted via the output shaft 24.sub.a is higher than the drive torque. This shaft can therefore be dimensioned to be more compact and lighter than the output shaft 24.sub.b.

[0059] In addition, it becomes possible to save on bearings 40.sub.a, 40.sub.b, 40.sub.c, 40.sub.d, 40.sub.e. Regarding the bearings 40.sub.a, 40.sub.b, 40.sub.c, 40.sub.d, 40.sub.e shown in FIG. 1, for example, the bearings 40.sub.b and 40.sub.c can be saved.

[0060] A cooling circuit 48 is also shown in FIG. 1, which can supply both at least one brake unit 26.sub.a, 26.sub.b and also the electric motor 12 and/or a power electronics system 14 with coolant, such as water. The cooling circuit 48 has for example a coolant pump and optionally a reservoir for coolant and also coolant lines 50 through which the corresponding components can be supplied with coolant and thereby cooled.

[0061] The refinement according to FIG. 2 largely corresponds to the refinement according to FIG. 1, and therefore the above statements also apply to the refinement according to FIG. 2, with the exception that, according to FIG. 2, the first distance D.sub.1 between the differential 22 and the first brake unit 26.sub.a and the second distance D.sub.2 between the differential 22 and the second brake unit 26.sub.b is substantially the same. In FIG. 2, the first brake unit 26.sub.a and also the second brake unit 26.sub.b are located below the electric motor 12 and on one side of same, which enables a reduced axial space requirement, i.e. parallel to the first output shaft 24.sub.a and thus approximately parallel to a vehicle axis. In addition, additional lubricant lines 44 may be dispensed with. Furthermore, lubricant volume can be correspondingly saved. Further savings can be permitted, for example, because bearings 40.sub.a, 40.sub.b, 40.sub.c, 40.sub.d, 40.sub.e can be dispensed with, such as, for example, the bearing 40.sub.b located directly to the left of the first brake unit 26.sub.a in FIG. 2.sub.b, as a result of which in turn costs and weight can be saved.

[0062] It remains to be added that the present embodiments may further extend to an interconnected vehicle drive and braking system which, for the sake of efficiency, may have interlinked electronic control or regulation methods for regulation of the fluid flow. Said drive system with the two fluid circuits can have an integrated electronic controller or regulator. As a result, controlled or regulated adaptation of braking power and/or cooling power can be undertaken jointly or in separately metered fashion by influencing the corresponding circulation (of coolant and/or lubricant) individually or in mutually coordinated and electronically controlled or regulated fashion as required. The control or regulation of pump capacity for lubricant circulation and/or coolant circulation may take place on the basis of regulation of the fluid pressure as required and in an energy-efficient manner. This may be done, for example, using one or more electrohydraulic pressure control valves, and it may be useful or necessary for regulation purposes to measure the respective fluid pressure (actual pressure) using one or more fluid pressure sensors and to make it available to an electronic control unit, which on the basis thereof controls or regulates the lubricant pump and/or coolant pump, which may be driven by an electric motor, as required, depending on the driving request and/or braking request, and optionally in mutually coordinated fashion. This control and/or regulation in an application in connection with automated driving is carried out in full or in part with data comparison with the drive and braking requirements, may be regulated in an automated manner. In this context, the control unit can be integrated as a central one box solution for the purpose of controlling the combined drive unit, and the central control unit is electronically connected to peripheral vehicle electronics and embedded in a network, and furthermore preferably there is at least one interface for the purpose of data exchange and/or control coordination in conjunction with C2C (car-to-car) and/or C2X (car-to-X) communication systems.