ELECTRIC AXLE FOR DRIVING A MOTOR VEHICLE

Abstract

Electric axle (2) for driving a motor vehicle, comprising a first electric drive system (4) which is designed to drive a first vehicle wheel (6) assigned to the electric axle (2), a second electric drive system (8) which is designed to drive a second vehicle wheel (10) assigned to the electric axle, and an inverter (12) which, viewed along a longitudinal direction (L) of the electric axle, is arranged between the first electric drive system (4) and the second electric drive system (8), wherein the first electric drive system (4) and the second electric drive system (8) each have the following components: an electric motor (14, 14'), having a stator (16, 16') and a rotor (18, 18'), wherein the rotor (18, 18') is designed as a double rotor and has a planetary gear (24, 24').

Description

[0001] The present invention relates to an electric axle for driving a motor vehicle.

[0002] According to the invention, an electric axle for driving a motor vehicle is specified, comprising a first electric drive system which is designed to drive a first vehicle wheel assigned to the electric axle, comprising a second electric drive system which is designed to drive a second vehicle wheel assigned to the electric axle, comprising an inverter which, viewed along a longitudinal direction of the electric axis, is arranged between the first electric drive system and the second electric drive system, wherein the first electric drive system and the second electric drive system each have the following components: an electric motor, with a stator and with a rotor, wherein the rotor is designed as a double rotor, and a planetary gear.

[0003] Accordingly, a speed and a torque of the first vehicle wheel can be precisely controlled by means of the first electric drive system, while a speed and a torque of the second vehicle wheel can be precisely controlled by means of the second electric drive system.

[0004] It can be provided that the first electric drive system and the second electric drive system additionally each have the following components: a compound planetary gear, such as a Ravigneaux planetary gear or the like, and / or two clutches for switching two gears of the compound planetary gear or three clutches for switching three gears of the compound planetary gear.

[0005] The first electric drive system, which in the fully assembled state drives the first vehicle wheel of a motor vehicle, accordingly has, for example, an electric motor with a stator and with a rotor, wherein the rotor is designed as a double rotor and surrounds the stator in the radial direction on two sides with an outer rotor section and an inner rotor section, a planetary gear, a compound planetary gear, such as a Ravigneaux planetary gear or the like, and three clutches for switching three gears of the compound planetary gear.

[0006] The second electric drive system, which in the fully assembled state drives the second vehicle wheel of a motor vehicle, accordingly also has, for example, an electric motor with a stator and a rotor, wherein the rotor is designed as a double rotor and surrounds the stator in the radial direction on two sides with an outer rotor section and an inner rotor section, a planetary gear, a compound planetary gear, such as a Ravigneaux planetary gear or the like, and three clutches for switching three gears of the compound planetary gear.

[0007] Here too, a speed and a torque of the first vehicle wheel can be precisely controlled by means of the first electric drive system, while a speed and a torque of the second vehicle wheel can be precisely controlled by means of the second electric drive system.

[0008] For the first and second electric drive systems of the electric axle, the respective combination of the electric motor with double rotor with the planetary gear and the optional compound planetary gear with its, for example, three gears enables efficient operation of the respective electric motor over a wide speed and torque range.

[0009] The arrangement of the inverter between the first electric drive system and the second electric drive system enables compact axial integration of the inverter into the electric axis. The inverter is designed to control all electric motors of the electric axis. For this purpose, it can also consist of two or more inverter subassemblies arranged spatially adjacent to one another between the first electric drive system and the second electric drive system.

[0010] The rotors, planetary gears, and composite planetary gears of the electric axle can be arranged coaxially. This allows for a compact design of the electric axle.

[0011] That is, the rotor, the planetary gear, and the composite planetary gear of the first electric drive system can be arranged coaxially with each other. Furthermore, the rotor, the planetary gear, and the composite planetary gear of the second electric drive system can be arranged coaxially with each other.

[0012] Furthermore, the first electric drive system and the second electric drive system can be arranged coaxially with each other. Accordingly, the rotor, planetary gear, and compound planetary gear of the first electric drive system can be arranged coaxially with the rotor, planetary gear, and compound planetary gear of the second electric drive system.

[0013] Furthermore, the couplings of the first electric drive system can be arranged coaxially to each other and coaxially to the couplings of the second electric drive system.

[0014] In addition, the clutches of the first electric drive system can be arranged coaxially to the rotor, planetary gear and compound planetary gear of the first electric drive system.

[0015] The clutches of the second electric drive system can be arranged coaxially to the rotor, planetary gear and compound planetary gear of the second electric drive system.

[0016] The coaxial arrangement allows for variable structural adaptation of the electric axis by adding coaxial components such as additional planetary gears and / or electric motors coaxially.

[0017] The electrical axis can be constructed with mirror symmetry. In particular, the electrical axis can be arranged with mirror symmetry to a plane of symmetry oriented perpendicular to the longitudinal axis of the electrical axis. The inverter can be arranged centrally at the level of the plane of symmetry, viewed along the longitudinal axis of the electrical axis.

[0018] The first electric drive system and the second electric drive system can each comprise a further electric motor with a further rotor, wherein the further electric motor uses the same stator that is also assigned to the electric motor, wherein the further rotor is designed as a double rotor. The common stator can also be structurally composed of two spatially adjacent stators that are electrically connected to form a common stator.

[0019] The first electric drive system can therefore have two double rotors that use a common stator, thus creating two electric motors of the first electric drive system. The first electric drive system therefore has two electric motors, which, to distinguish them, are referred to as the electric motor of the first electric drive system and the further electric motor of the first electric drive system. The electric motor of the first electric drive system can also be referred to as the first electric motor of the first electric drive system. The further electric motor of the first electric drive system can also be referred to as the second electric motor of the first electric drive system.

[0020] The second electric drive system can therefore have two double rotors that use a common stator to create two electric motors of the second electric drive system. The second electric drive system therefore has two electric motors, which are referred to as the electric motor of the second electric drive system and the further electric motor of the second electric drive system to distinguish them. The electric motor of the second electric drive system can also be referred to as the first electric motor of the second electric drive system. The further electric motor of the second electric drive system can also be referred to as the second electric motor of the second electric drive system.

[0021] For the first electric drive system and the second electric drive system, it can be provided that the respective planetary gear is assigned to a wheel hub.

[0022] Thus, the planetary gear of the first electric drive system can be assigned to a wheel hub of the first vehicle wheel, while the planetary gear of the second electric drive system can be assigned to a wheel hub of the second vehicle wheel.

[0023] The first electric drive system and the second electric drive system may each comprise: a further planetary gear, wherein the further planetary gear is installed as a reduction gear between the electric motor and the compound planetary gear.

[0024] The first electric drive system can therefore have two planetary gears in addition to the composite planetary gear, which are referred to as the planetary gear of the first electric drive system and as the further planetary gear of the first electric drive system for the purpose of differentiation. The planetary gear of the first electric drive system can also be referred to as the first planetary gear of the first electric drive system. The further planetary gear of the first electric drive system can also be referred to as the second planetary gear of the first electric drive system.

[0025] The second electric drive system can therefore have two planetary gears in addition to the composite planetary gear, which are referred to as the planetary gear of the second electric drive system and the further planetary gear of the second electric drive system for the purpose of differentiation. The planetary gear of the second electric drive system can also be referred to as the first planetary gear of the second electric drive system. The further planetary gear of the second electric drive system can also be referred to as the second planetary gear of the second electric drive system.

[0026] For the first electric drive system and the second electric drive system, it can be provided that the three clutches are each designed as positive-locking clutches, such as a claw clutch or the like. Accordingly, the first electric drive system can have three positive-locking clutches, in particular three claw clutches. Furthermore, the second electric drive system can have three positive-locking clutches, in particular three claw clutches.

[0027] The electric axle can be designed such that no additional mechanical differential gear is provided. In this case, the electric axle therefore has the aforementioned planetary gears and compound planetary gears of the first and second electric drive systems, but no differential gear. The first vehicle wheel and the second vehicle wheel are therefore not mechanically connected by means of a differential gear. The first electric drive system and the second electric drive system, in particular, cannot be coupled to one another. In other words, in particular, no mechanical drive power can be transmitted from the first electric drive system to the second electric drive system, or vice versa.

[0028] It can be provided that the double rotor surrounds the stator in the radial direction on two sides with an outer rotor section and an inner rotor section.

[0029] Alternatively, it can be provided that the electric motor is constructed according to the axial flux principle and the double rotor encloses the stator in the axial direction on two sides with a left rotor section and a right rotor section.

[0030] The invention is described in more detail below with reference to exemplary embodiments of the drawings. They show schematically: Fig. 1 a first electric axis; Fig. 2 a second electric axis; Fig. 3 a third electric axis; Fig. 4 a fourth electric axle.

[0031] Fig. Figure 1 shows a first electric axle 2 for driving a motor vehicle. The electric axle 2 has a first electric drive system 4, which is configured to drive a first vehicle wheel 6 associated with the electric axle 2.

[0032] The electric axle 2 has a second electric drive system 8 which is configured to drive a second vehicle wheel 10 associated with the electric axle 2.

[0033] The electric axis 2 has an inverter 12. The inverter 12 is arranged between the first electric drive system 4 and the second electric drive system 8, viewed along a longitudinal direction L or longitudinal axis L of the electric axis 2.

[0034] The first electric drive system 4 comprises an electric motor 14 with a stator 16 and a rotor 18. The rotor 18 is designed as a double rotor and encloses the stator 16 on two sides in the radial direction with an outer rotor section 20 and an inner rotor section 22.

[0035] The first electric drive system 4 has a planetary gear 24.

[0036] The first electric drive system 4 has a compound planetary gear 26.

[0037] The first electric drive system 4 has three clutches 28, 30, 32 for shifting three gears of the compound planetary gear 26. The three clutches 28, 30, 32 are each claw clutches.

[0038] The following switching positions of the clutches 28, 30, 32 apply to the three gears of the combined gearbox 26: Clutch 28 Clutch 30 Clutch 32 1st gear closed open open 2nd gear open closed open 3rd gear open open closed

[0039] The first electric drive system 4 has a further electric motor 34. The further electric motor 34 has a further rotor 36. The further electric motor 34 uses the same stator 16 that is also associated with the electric motor 14.

[0040] The further rotor 36 is designed as a double rotor and encloses the stator 16 in the radial direction on two sides with an outer rotor section 38 and an inner rotor section 40.

[0041] A rotor bearing 42 is assigned to the rotors 18, 36.

[0042] The planetary gear 24 is assigned to a wheel hub 44 of the first vehicle wheel 6.

[0043] The first electric drive system 4 has an additional planetary gear 46. The additional planetary gear 46 is installed as a reduction gear between the electric motors 14, 34 and the composite planetary gear 26.

[0044] The second electric drive system 4 comprises an electric motor 14' with a stator 16' and a rotor 18'. The rotor 18' is designed as a double rotor and encloses the stator 16' on two sides in the radial direction with an outer rotor section 20' and an inner rotor section 22'.

[0045] The second electric drive system 8 has a planetary gear 24'.

[0046] The second electric drive system 8 has a compound planetary gear 26'.

[0047] The second electric drive system 8 has three clutches 28', 30', 32' for shifting three gears of the compound planetary gear 26'. The three clutches 28', 30', 32' are each claw clutches.

[0048] The following switching positions of the clutches 28', 30', 32' apply to the three gears of the compound gearbox 26': Coupling 28' Coupling 30' Clutch 32 1st gear closed open open 2nd gear open closed open 3rd gear open open closed

[0049] The second electric drive system 8 includes another electric motor 34'. The other electric motor 34' has another rotor 36'. The other electric motor 34 uses the same stator 16' that is also associated with the electric motor 14'.

[0050] The further rotor 36' is designed as a double rotor and encloses the stator 16' in the radial direction on two sides with an outer rotor section 38' and an inner rotor section 40'.

[0051] The rotors 18', 36' are assigned a rotor bearing 42'.

[0052] The planetary gear 24' is assigned to a wheel hub 44' of the second vehicle wheel 10.

[0053] The second electric drive system 8 has a further planetary gear 46'. The further planetary gear 46' is installed as a reduction gear between the electric motors 14', 34' and the composite planetary gear 26'.

[0054] The rotors 20, 22, 20', 22', the planetary gears 24, 24', 46, 46' and the compound planetary gears 26, 26' of the electric axis 2 are arranged coaxially.

[0055] The electrical axis 2 is mirror-symmetrical.

[0056] The electric axle 2 does not have an additional mechanical differential gear.

[0057] Fig.2 shows a second electrical axis 48, wherein, to avoid repetition, only the differences from the embodiment described above are discussed and the same features are assigned the same reference numerals.

[0058] The second electric axis 48 differs from the first electric axis 2 in that the second electric axis 48 does not have any further planetary gears 46, 46', but the electric motors 14, 14', 34, 34' are directly connected to the respectively associated composite gears 26, 26'.

[0059] Fig. 3 shows a third electrical axis 50, whereby, to avoid repetition, only the differences from the previously described embodiment according to Fig. 1 and the same features are assigned the same reference symbols.

[0060] The third electric axle 50 differs from the first electric axle 2 in that the third electric axle 50 does not have electric motors 34, 34', but only electric motors 14, 14'. The third electric axle 50 therefore has two electric motors, while the first electric axle 2 has four electric motors.

[0061] Fig. 4 shows a fourth electrical axis 52, whereby, to avoid repetition, only the differences from the previously described embodiment according to Fig. 1 and the same features are assigned the same reference symbols.

[0062] The fourth electric axis 52 differs from the first electric axis 2 in that the fourth electric axis 52 does not have any further planetary gears 46, 46', but the electric motors 14, 14' are directly connected to the respectively associated composite gears 26, 26'.

[0063] The fourth electric axle 52 also differs from the first electric axle 2 in that the fourth electric axle 52 does not have electric motors 34, 34', but only electric motors 14, 14'. The fourth electric axle 52 therefore has two electric motors, while the first electric axle 2 has four electric motors.

Claims

[1] Electric axle for driving a motor vehicle, - with a first electric drive system (4) which is designed to drive a first vehicle wheel (6) assigned to the electric axle, - with a second electric drive system (8) which is designed to drive a second vehicle wheel (10) assigned to the electric axle, - with an inverter (12) which, viewed along a longitudinal direction (L) of the electrical axis, is arranged between the first electrical drive system (4) and the second electrical drive system (8), - wherein the first electric drive system (4) and the second electric drive system (8) each have the following components: - an electric motor (14, 14') with a stator (16, 16') and with a rotor (18, 18'), wherein the rotor (18, 18') is designed as a double rotor and - a planetary gear (24, 24'). [2] Electric axle according to one of the preceding claims, characterized by that the first electric drive system (4) and the second electric drive system (8) additionally each have the following components: - a compound planetary gear (26, 26'), such as a Ravigneaux planetary gear or the like, and / or - two clutches for shifting two gears of the compound planetary gear or three clutches (28, 30, 32, 28', 30', 32') for shifting three gears of the compound planetary gear (26, 26'). [3] Electric axle according to claim 2, characterized by that the rotors (18, 18'), the planetary gears (24, 24') and the compound planetary gears (26, 26') of the electric axis are arranged coaxially. [4] Electric axle according to one of the preceding claims, characterized by that the electrical axis is mirror-symmetrical. [5] Electric axle according to one of the preceding claims, characterized by that the first electric drive system (4) and the second electric drive system (8) each have: - a further electric motor (34, 34') having a further rotor (36, 36'), wherein the further electric motor (34, 34') uses the same stator (16, 16') as is associated with the electric motor (14, 14'), - wherein the further rotor (36, 36') is designed as a double rotor and surrounds the stator (16, 16') in the radial direction on two sides with an outer rotor section (38, 38') and an inner rotor section (40, 40'). [6] Electric axle according to one of the preceding claims, characterized by that for the first electric drive system (4) and the second electric drive system (8) it is provided that the respective planetary gear (24, 24') is assigned to a wheel hub (44, 44'). [7] Electric axle according to one of the preceding claims 2 or 3, characterized by that the first electric drive system (4) and the second electric drive system (8) each have: - another planetary gear (46, 46'), - wherein the further planetary gear (46, 46') is installed as a reduction gear between the electric motor (14, 14') and the compound planetary gear (26, 26'). [8] Electric axle according to one of the preceding claims, characterized by that for the first electric drive system (4) and the second electric drive system (8) it is provided that clutches (28, 30, 32, 28', 30', 32') are each designed as a positive-locking clutch, such as a claw clutch or the like. [9] Electric axle according to one of the preceding claims, characterized by that no additional mechanical differential gear is provided. [10] Electric axle according to one of the preceding claims, characterized by , that the double rotor surrounds the stator (16, 16') in the radial direction on two sides with an outer rotor section (20, 20') and an inner rotor section (22, 22') or the electric motor is constructed according to the axial flux principle and the double rotor encloses the stator in the axial direction on two sides with a left rotor section and a right rotor section.

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