Rotating electric machine

Abstract

Rotating electric machine (10) with: - a stator (12) having a winding head (16) at each axial end, - a rotor (40) rotatably mounted in an opening of the stand (12), which has a rotor shaft (24) and a rotor lamination stack (26), - a bearing unit (30) for rotatably supporting the rotor shaft (24) relative to the rotor lamination stack (26), - a gear unit (46), and - a coupling unit (42, 48) which is configured to provide at least two coupling states for rotationally coupling the rotor shaft (24) with the rotor lamination stack (26) and in at least one of the coupling states to couple the rotor shaft (24) with the rotor lamination stack (26) by means of the transmission unit (46), wherein the coupling unit (42, 48) has an actuator (32) arranged in the rotor shaft (24) and mounted to be displaceable in an axial direction of the rotor shaft (24) for actuating the coupling unit (42, 48).

Description

[0001] The present invention relates to a rotating electric machine with a stator having a winding head at each axial end and a rotor rotatably mounted in an opening of the stator, the rotor having a rotor shaft and a rotor lamination stack. The invention further relates to a rotor for a rotating electric machine.

[0002] Electrical machines of this type, as well as their stators, are fundamentally known in the prior art, so that a separate printed reference is not required. In a rotating electrical machine, a stator is generally provided, which typically has a substantially circular opening for receiving a rotor. The rotor is rotatably mounted in the opening, with an air gap between the rotor and the stator.

[0003] A rotating electric machine is a device that converts electrical energy into mechanical energy, in particular kinetic energy (motor operation) and / or mechanical energy into electrical energy (generator operation). The movement is generally a rotary motion performed by the rotor. Unlike the rotor, the stator is fixed against rotation; that is, the rotary motion is a rotational movement of the rotor relative to the stator.

[0004] The stator and rotor are linked by a magnetic flux, which, in motor operation, generates the force, namely the torque, that drives the rotor to rotate relative to the stator. In generator operation, this torque converts the mechanical energy supplied to the rotor into electrical energy in the form of a rotary motion. For this purpose, the stator and the rotor each have a winding through which an electric current flows. Winding heads are formed at the axial ends of the stator and / or, if applicable, the rotor, to allow the winding to be configured in a predetermined manner. The winding in the stator or rotor can also be formed or supplemented by a permanent magnet.

[0005] Rotating electrical machines of the generic type are, for example, rotating field machines that are connected to a multi-phase, in particular three-phase, alternating current electrical network, such as asynchronous machines, synchronous machines, synchronous machines with damper cage or the like, or also DC machines such as shunt-wound or series-wound machines or the like.

[0006] Rotating electric machines are used in various applications, including electrically powered vehicles such as electric vehicles, hybrid vehicles, and the like. Although electric drives have proven successful in the automotive sector, it has proven advantageous to couple the rotating electric machine to the vehicle's driven wheels via a transmission, particularly for electric drives in vehicles capable of covering longer distances purely electrically. The transmission can provide various functions, enabling high acceleration in a first gear and a high top speed in another gear. It is common practice to use manually operated gearboxes or automatic transmissions, such as those used in internal combustion engines, for this purpose.This also makes it possible for electrically powered vehicles, especially passenger cars, to reach speeds in the range of approximately 160 to 200 km / h. Even higher speeds, up to, for example, 250 km / h, are possible.

[0007] In such an application, the use of a gearbox is generally necessary to achieve the desired power output, even if the rotating electric machine is capable of covering a significantly wider speed range than is possible with an internal combustion engine. DE 10 2007 034 149 A1 discloses an electric motor-gearbox unit.

[0008] The invention is based on the objective of further developing a generic rotating electric machine and a rotor for it in such a way that a large speed range, in particular for use in electrically powered motor vehicles, can be achieved with minimal effort.

[0009] The invention proposes a rotating electric machine and a runner according to the independent claims as a solution.

[0010] Further advantageous configurations arise from the characteristics of the dependent claims.

[0011] With regard to a generic rotating electric machine, it is particularly proposed that the rotating electric machine has a bearing unit for rotatably supporting the rotor shaft relative to the rotor lamination stack, a gear unit and a coupling unit configured to provide at least two coupling states for rotationally coupling the rotor shaft to the rotor lamination stack and to couple the rotor shaft to the rotor lamination stack in at least one of the coupling states by means of the gear unit.

[0012] On the rotor side, it is particularly proposed for a generic rotor that the bearing unit, the gear unit, the clutch unit and / or a fluid power drive unit are formed in one piece with the rotor.

[0013] The invention makes it possible to provide a transmission function simultaneously with the rotating electric machine, allowing for at least two different gear ratios. This is achieved by rotationally decoupling the rotor shaft from the lamination stack. This decoupling is accomplished by providing a bearing unit that allows the rotor shaft to be rotatably mounted relative to the rotor lamination stack. For this purpose, the bearing unit can be arranged between the rotor shaft and the rotor lamination stack and, for example, provide suitable rolling elements. These rolling elements can be in the form of needle rollers or similar devices. Alternatively, a sliding bearing can also be provided to achieve the desired bearing arrangement.

[0014] Preferably, the bearing unit extends over a large axial section of the rotor, in particular over the entire extent of the rotor lamination stack. Alternatively, a plurality of rolling element bearings may be provided, arranged axially spaced between the rotor lamination stack and the rotor shaft. Furthermore, it is of course possible for the rotor shaft and the rotor lamination stack to be supported separately, for example by means of bearing shields that are connected either to a foundation and / or to a housing of the rotating electric machine. The transmission unit preferably includes mechanical elements that allow a speed or torque transmission between a drive shaft and an output shaft of the transmission unit.For this purpose, the gear unit preferably has meshing gears that can be coupled or connected to the rotor lamination stack on the one hand by rotational technology and to the rotor shaft on the other.

[0015] The coupling is achieved by means of the coupling unit, which has at least two coupling states. In a first coupling state, the rotor shaft can be coupled to the rotor lamination stack via the transmission unit. Due to the interposition of the transmission unit, the rotor shaft rotates at a different speed than the rotor lamination stack. The rotational connection is achieved through the transmission unit. Furthermore, the transmission unit can also have two output shafts that can be coupled to the rotor shaft via the coupling unit and that can provide different rotational speeds. Preferably, they are reciprocally couplingable, so that the rotor shaft is always coupled to only one of the output shafts of the transmission unit.

[0016] For the purpose of rotary coupling, the coupling unit can, for example, have friction-fit or positive-fit coupling elements. The use of friction-fit coupling elements proves particularly advantageous, as it allows for load-shifting. This enables different effects to be achieved, such as high acceleration in first gear and a high top speed in at least one second gear. The gear changes can preferably be performed without a noticeable reduction in tractive force.

[0017] By integrating a preferably load-shiftable, at least two-speed transmission into the rotating electric machine, a simple and cost-effective design of a rotating electric machine for any drive application can be achieved. In particular, the rotating electric machine of the invention can be easily combined with existing transmissions in known vehicle designs.

[0018] The invention is not limited to the use of rotating electric machines in electrically powered motor vehicles. In principle, the rotating electric machine of the invention can also be used in machine tools, household appliances with electric drives, robots, particularly in production environments, conveyor belts, printing presses, and / or the like. The invention makes it possible to easily equip the rotating electric machine with an integrated gearbox having at least two gears. This further increases the flexibility in the field of electric drives. The invention not only reduces the complexity of gearboxes but can even eliminate the need for external gearboxes altogether.

[0019] Furthermore, the coupling unit comprises an actuator arranged in the rotor shaft and mounted to be axially displaceable along the rotor shaft for actuating the coupling unit. The actuator can, for example, have a rod arranged in an axial bore of the rotor shaft. The actuator can be driven by a drive unit, which is preferably also integrated into the rotor. Alternatively, it can also be arranged at least partially external to the rotor. Preferably, however, it is part of the rotating electric machine. The actuator acts in particular on the coupling elements of the coupling unit, by means of which the at least two coupling states can be realized.It can be designed so that a friction-fit coupling element allows for axial displacement, for example, to directly couple the rotor shaft to the rotor lamination stack at its end face. The same can, of course, be provided for a coupling element that allows the gearbox unit to be interposed between the rotor shaft and the rotor lamination stack. This allows for the simple implementation of both gearbox and coupling functions.

[0020] According to an advantageous embodiment, it is proposed that the coupling unit, in one of the coupling states, is designed for the direct rotational coupling of the rotor shaft to the rotor lamination stack. In this coupling state, it is preferably provided that the rotor shaft and the rotor lamination stack rotate at the same speed. For this purpose, the coupling unit can be designed to couple the rotor shaft directly to the rotor lamination stack, without a gear unit, i.e., without the interposition of a gear unit. This further simplifies the gear unit. In this case, it only needs to be operational and configured for one of the two coupling states. By directly coupling the rotor shaft to the rotor lamination stack, a first gear of the rotating electric machine can be easily provided.For this purpose, the coupling unit may provide a friction-fit coupling element, which, for example, frictionally couples the rotor lamination stack to one of its end faces, thus establishing the rotational coupling between the rotor shaft and the rotor lamination stack. Alternatively, a jaw coupling unit may be provided to achieve this coupling. Further combinations and configurations of the coupling unit are also possible.

[0021] According to a further embodiment, it is proposed that the coupling unit be designed to automatically assume a predetermined coupling state. "Automatically" here means, in particular, that there is no need to supply external actuation energy. Preferably, the coupling state is maintained automatically without the supply of energy. Particularly preferably, an energy supply is only required for switching from one coupling state to another. For this purpose, the coupling unit can be pre-tensioned to assume the predetermined coupling state. This can be achieved, for example, by means of an elastic element, in particular a spring element.This design proves advantageous in that even in the event of malfunctions of the coupling unit or an actuating device for the coupling unit, a coupled state between the rotor shaft and the rotor lamination stack can be maintained, thus ensuring a drive function in all cases. This further improves the reliability of the rotating electric machine.

[0022] An advantageous embodiment of the invention provides that the coupling unit is configured to automatically assume the coupling state depending on the direction of rotation of the lamination stack. For example, the automatically assumed coupling state can be implemented by means of a freewheel unit, so that coupling occurs only in a single direction of rotation of the rotor lamination stack. In the other direction of rotation of the rotor lamination stack, the rotor shaft is thereby decoupled. In this case, it can be coupled via the gearbox in the other of the two coupling states.

[0023] The clutch unit has at least two clutch states. However, it can also have several clutch states, particularly if the transmission unit is designed to provide a corresponding number of gears.

[0024] The transmission unit can advantageously incorporate a planetary gear set. A planetary gear set allows for the simple provision of a heavy-duty transmission capable of achieving the desired transmission function. Furthermore, the use of a planetary gear set enables a multitude of different gear ratios, thus increasing flexibility in providing various gear configurations. For example, the rotor lamination stack can be connected to a ring gear of the planetary gear set, while a planet carrier of the planetary gear set is rotationally connected to the rotor shaft. A sun gear of the planetary gear set is preferably connectable to a non-rotating machine part of the rotating electric machine via the coupling unit.By coupling the planetary gear to the non-rotating machine part, the planetary gear can be rotationally fixed in the coupled state. This allows the rotating rotor lamination stack and the resulting drive of the ring gear to achieve a rotational drive function with respect to the rotor shaft via the planet carrier, thereby providing a suitable gear ratio. Conversely, if the rotor lamination stack is directly coupled to the rotor shaft in the other coupling state, the coupling between the planetary gear and the non-rotating machine part is removed, and the planetary gear system no longer provides a coupling function between the rotor lamination stack and the rotor shaft. In this way, a reliable transmission function in the rotating electric machine can be achieved with just a few components.Depending on requirements, it is also possible to have the rotor shaft connected to the ring gear and the rotor lamination stack connected to the planet carrier in a rotational manner. In this case, a different transmission range results with regard to the gear ratio, which can be achieved with the planetary gear.

[0025] Furthermore, the invention proposes that the gear unit and / or the coupling unit be arranged at least partially in a region extending between the rotor shaft and at least one of the winding heads. This allows the coupling unit and / or the gear unit to be at least partially integrated into the rotating electric machine, thus providing a separately manageable component. In particular, if the coupling unit and / or the gear unit are arranged completely in this region, a very compact design can be achieved, so that an existing housing or other machine parts of the rotating electric machine can largely be reused. This further reduces the effort required to provide the gear function in the rotating electric machine.In particular, the invention can thus be easily retrofitted to existing design concepts for rotating electrical machines.

[0026] It proves particularly advantageous if the coupling function is implemented at both end faces of the rotor. This allows for efficient use of space in the winding head area, resulting in a high integration density. For this purpose, for example, an axially displaceable laminated core can be provided. This can be achieved using an axially displaceable laminated core support unit.

[0027] A further embodiment of the invention provides that the rotating electric machine has a fluid power drive unit for driving the actuator. The fluid power drive unit can be, for example, a pneumatic or a hydraulic drive unit. The use of a hydraulic drive unit is particularly advantageous, especially if the rotating electric machine already incorporates liquid cooling. In this way, a drive function for the clutch unit and, if necessary, also for the transmission unit, for example to perform a gear change or the like, can be achieved with just a few additional components.

[0028] Preferably, the fluid power drive unit comprises a fluid pump that can be rotationally coupled to an electric motor. This allows the drive unit to function independently of the operation of the rotating electric motor. Furthermore, this allows for a separate fluid circuit for the drive unit, ensuring suitable fluid properties such as pressure, flow rate, and / or the like. This enables particularly efficient drive operation for the coupling unit and, if applicable, also for the transmission unit. In a hydraulic drive unit, the fluid pump is preferably a liquid pump, such as a vane pump, a gear pump, a radial pump, and / or the like. In a pneumatic drive unit, the pump is preferably a gas pump, in particular an air pump of the type of compressor or the like.

[0029] Furthermore, it is proposed that the fluid power drive unit be designed to decouple the fluid pump from the electric motor rotationally when the coupling state is automatically engaged. This ensures that energy for the drive unit only needs to be supplied when the coupling state required by the coupling unit actually necessitates it. For example, if the coupling state is automatically engaged by the coupling unit, no further energy is required to maintain this coupling state. Therefore, the additional drive of the fluid pump can be eliminated. Overall, this results in more efficient operation of the rotating electric machine. The rotational decoupling can be achieved, for example, by coupling the fluid pump to the electric motor via a freewheel mechanism.This means the fluid pump is only driven when the electric motor rotates in the corresponding coupling direction. If the electric motor rotates in the opposite direction, the freewheel decouples the electric motor from the fluid pump. This allows the desired coupling function to be implemented simply.

[0030] One further development proposes that the fluid power drive unit be configured to operate the fluid pump exclusively while the clutch unit is being actuated. In this further development, the fluid pump only needs to be actuated during a change in the clutch unit's engagement state. This further development can be particularly advantageous if the fluid supply is independent of any cooling and / or lubrication functions. For this purpose, the fluid pump can be connected to the electric motor via a freewheel, so that operating the electric motor in a specific direction of rotation engages the fluid pump.

[0031] The designs, effects and advantages specified for the rotating electric machine can of course also be achieved with the rotor for the rotating electric machine.

[0032] Furthermore, with regard to the rotor, the invention proposes that the bearing unit, the gear unit, the coupling unit, and / or the fluid power drive unit be formed integrally with the rotor. This allows the rotor to be provided as a separately handleable assembly. Moreover, a high integration density can be achieved. This proves particularly advantageous if an existing stator can be used to implement the invention. No modifications to the stator are necessary to integrate the invention into the rotating electric machine. This facilitates the retrofitting of the invention into existing design concepts for rotating electric machines.

[0033] Further advantages and features can be found in the following description of exemplary embodiments. In the figures, the same reference numerals denote the same features and functions. The exemplary embodiments serve only to illustrate the invention and are not intended to limit it.

[0034] They show: Fig. 1. Schematic cross-sectional view through a rotating electric machine, Fig. 2 a schematic representation of the rotating machine according to Fig. 1 with illustrated installation spaces for a transmission unit and a clutch unit according to the invention, Fig. 3 in a schematic functional view a first embodiment of a rotor according to the invention for a rotating electric machine according to Fig. 1, Fig. 4 a schematic functional representation of the clutch unit and the transmission unit according to Fig. 3, Fig. 5 in a schematic functional view a second embodiment of a rotor according to the invention for the rotating electric machine according to Fig. 1, Fig. 6 a schematic functional representation of the clutch unit and the transmission unit according to Fig. 5, Fig. 7 a schematic representation of a first coupling state of the coupling unit of the runner according to Fig. 5, Fig. 8 a schematic representation of a second coupling state of the coupling unit of the runner according to Fig. 5, Fig. 9 a schematic circuit diagram of a first embodiment for a hydraulic drive unit for actuating the clutch unit, and Fig. 10 a schematic circuit diagram of a second embodiment for a hydraulic drive unit for actuating the clutch unit.

[0035] A schematic sectional view shows Fig. 1 A rotating electric machine 10 with a stator 12 comprising a winding 20 and a stator lamination stack 22. At each axial end of the stator 12, a winding head 16 of the winding 20 is formed. A rotor 14 is rotatably mounted in a substantially circular opening of the stator 12. The rotor 14 has a rotor shaft 24 and a rotor lamination stack 26. Bearing shields 18 are arranged at each axial end of the rotating electric machine 10, of which in Fig. Figure 1 shows only the right bearing shield. Rolling bearings 86 are positioned on the bearing shields 18, which rotatably fix the rotor shaft 24 in the radial direction. Reference numeral 88 denotes a mechanical connection of the rotor shaft 24 to which a driven device can be connected.

[0036] Fig. Figure 2 shows a schematic sectional view of a rotating electric machine 10 according to the invention, which is mounted on the in Fig. The rotating electric machine shown in 10 is based on this. In contrast to the rotating electric machine according to Fig. 1 shows the rotating electric machine 10 according to Fig. 2 instead of the rotor 14, a rotor 40 is mounted, which also comprises a rotor shaft 24 and a rotor lamination stack 26. However, the rotor lamination stack 26 is rotatably mounted relative to the rotor shaft 24 via a bearing unit 30. In this case, the bearing unit 30 comprises a plurality of rolling elements in the form of needle rollers. Installation spaces 28 are marked in which, as will be explained below, a gear unit 46 ( Fig. 3) and a coupling unit 42, 48 are arranged. The rotor shaft 24 is designed as a hollow shaft, the cavity providing a mounting space for an actuator 32. The other elements correspond to those already described for Fig. 1 have been explained, which is why, in this regard, reference is made to the explanations concerning Fig. 1 is referred to.

[0037] Fig. Figure 3 now shows a first design for the runner 40 according to Fig. 2. From Fig. Figure 3 shows that a first coupling element 42 of the coupling unit is arranged in the left area of ​​the rotor 40, which in this case is formed by a friction coupling. The friction coupling 42 is designed to rotate the rotor lamination stack 26 with the rotor shaft 24 in the coupled state. The first coupling element 42 can be actuated between a coupled and a non-coupled state by means of the actuator 32.

[0038] In the right area of Fig. Figure 3 further shows a planetary gear unit 46. Preferably, oil lubrication of the gear unit can simultaneously be used to cool the electric machine 10, in particular its winding heads 16. Furthermore, the planetary gear unit 46 can be coupled to a non-rotating machine element 54 by means of a second coupling element 48, which is also designed as a friction clutch. The second coupling element 48 can also be switched between a first and a second coupling state, for which purpose it can also be actuated by the actuator 32.

[0039] The present design provides that actuation by means of the actuator 32 alternately provides or releases a coupled state of the coupling elements 42, 48. The coupling elements 42, 48 are thus – except during a transition phase – always alternately in a coupled state.

[0040] Fig. Figure 4 shows a schematic functional view of the clutch unit 42, 48 and the planetary gear 46. In the left area in Fig. Figure 4 shows the friction clutch 42. The friction clutch 42 is non-rotatably connected on one side to a connecting element 44, which in turn is non-rotatably connected to the rotor shaft 24. On the other side, the friction clutch 42 is non-rotatably connected to a connecting element 50, which in turn is non-rotatably connected to the rotor lamination stack 26. In the engaged state, the friction clutch 42 thus establishes a rotational coupling between the connecting element 44 and the connecting element 50, so that the rotor shaft 24 and the rotor lamination stack 26 are directly coupled to each other rotationally.

[0041] In the right area of ​​the Fig. Figure 4 shows the planetary gear set 46 in conjunction with the second coupling element, here the friction clutch 48. Here, too, a connecting element 52 is non-rotatably connected to the rotor lamination stack 26. Simultaneously, the connecting element 52 is non-rotatably connected to a ring gear 56 of the planetary gear set 46. A planet carrier 66 of the planetary gear set 46 is non-rotatably connected to a connecting element 60, which in turn is non-rotatably connected to the rotor shaft 24. A sun gear 58 of the planetary gear set 46 is non-rotatably connected to one side of the friction clutch 48, whereas another side of the friction clutch 48 is non-rotatably connected to the machine element 54. Thus, by means of the friction clutch 48, the sun gear 58 can be coupled to the machine element 54 in the engaged state, so that the sun gear 58 does not rotate when the second coupling element 48 is engaged.In this state, the rotational movement of the lamination stack 26 is transmitted via the ring gear 56 to the planet carrier 66, which in turn transmits its rotational movement via the connecting element 60 to the rotor shaft 24. Thus, there is a speed difference between the rotor lamination stack 26 and the rotor shaft 24.

[0042] In the present embodiment, the rotor lamination stack 26 always has the same direction of rotation as the rotor shaft 24. Preferably, the rotor lamination stack 26 is coupled to the ring gear 56 and the rotor shaft 24 to the planet carrier 66, with the sun 58 being fixed. This is advantageous for the bearing of the rotor shaft 24 because it results in a comparatively low relative speed between the rotor lamination stack 26 and the rotor shaft 24.

[0043] In this configuration, the connection of the planetary gear set 46 further results in the rotational speed of the rotor shaft 24 being lower than the rotational speed of the rotor lamination stack 26. The gear ratio is therefore less than 1.

[0044] If, on the other hand, the friction clutch 48 is decoupled, the sun 58 can rotate freely, so that no rotational coupling via the planetary gear 46 is possible between the connecting elements 52 and 60.

[0045] The present design is therefore suitable for an electric machine 10 that is intended to generate a high torque during start-up. By switching the clutch unit 42, 48, it is possible to switch between a synchronous state, in which the rotational speed of the rotor lamination stack 26 and the rotor shaft 24 are equal, and a differential state, in which the rotational speed of the rotor lamination stack 26 is greater than that of the rotor shaft 24. The speed difference results from the design of the planetary gear set 46. Furthermore, the design as a friction clutch allows switching under load. A two-speed function is thus provided.

[0046] The figures also show that the planetary gear 46 and the coupling elements 42, 48 can be arranged essentially entirely within the installation spaces 28 between the rotor shaft 24 and the winding heads 16. This allows the invention to be easily integrated into existing design concepts for rotating electrical machines, as can be seen from the figures. Fig. 1 and Fig. 2 is evident.

[0047] Fig. 5 and Fig. 6 refer to a second embodiment for the runner 40, which is based on the first embodiment according to the Fig. 3 and Fig. 4. Consequently, in addition to the statements regarding the Fig. 3 and Fig. 4 referred to. In contrast to the first embodiment according to the Fig. 3 and Fig. 4 is in the second embodiment according to the Fig. 5 and Fig. 6 provides that the planetary gear 46 is connected to the rotor shaft 24 and the rotor lamination stack 26 in a different manner. In this case, the connecting element 52, which rotatably couples the rotor lamination stack 26, is rotatably connected to the planet carrier 66. Furthermore, the ring gear 56 of the planetary gear 46 is non-rotatably connected to the connecting element 60, which in turn is connected to the rotor shaft 24. Otherwise, the design of this embodiment with regard to the other components corresponds to what has already been described in relation to the Fig. 3 and Fig. 4 has been explained in relation to the first embodiment.

[0048] The design according to Fig. 5 and Fig. This results in the rotor shaft 24 having a higher rotational speed than the rotor lamination stack 26. This is due to the function of the planetary gear 46, which provides a gear ratio greater than 1 in this configuration. This allows the rotor shaft 24 to achieve a high rotational speed. At very high rotational speeds, the bearing unit 30 can also be designed as a plain bearing. However, other bearing elements can also be provided to allow the rotor shaft 24 to rotate relative to the rotor lamination stack 26.

[0049] In the Fig. 7 and Fig. 8 are in relation to the second embodiment according to the Fig. 5 and Fig. Figure 6 shows two switching states of the clutch unit 42, 48. Fig. 7 is the first coupling element, namely the friction clutch 42, which is in the disengaged state due to actuation by the actuator 32 in the axial direction 62. At this point, there is therefore no coupling between the rotor lamination stack 26 and the rotor shaft 24. Instead, the second coupling element, namely the friction clutch 48, is engaged, so that the sun 58 is clamped via the second coupling element 48 and the machine element 54 and does not rotate. Consequently, a rotational coupling is established between the rotor lamination stack 26 and the rotor shaft 24 via the planetary gear 46, as already described in the previous section. Fig. 5 and Fig. As explained in section 6. Both the first coupling element 42 and the second coupling element 48 are actuated by the actuator 32 in the same way.

[0050] Fig. Figure 8 now shows a second coupling state in which the actuator 32 is axially displaced in the direction of 64. This means that the first coupling element 42 is now in the engaged state and directly couples the rotor lamination stack 26 to the rotor shaft 24, so that they rotate together at the same speed. At the same time, the second coupling element 48 is in the disengaged state, allowing the sun 58 to rotate freely. Consequently, there is no coupling via the planetary gear 46 between the rotor shaft 24 and the rotor lamination stack 26.

[0051] Thus, the two coupling states, as described in the Fig. 7 and Fig. The coupling units 42 and 48, as shown in Figure 8, can be switched. By appropriately designing the coupling unit, switching under load is possible. This proves advantageous not only when using the rotating electric machine 10 in electrically powered motor vehicles, but also in machine tools or similar applications where a continuously acting torque is essential.

[0052] Fig. Figure 9 shows a schematic hydraulic block diagram illustrating a first embodiment of a hydraulic drive unit 90. The drive unit 90 utilizes a hydraulic system already present in the rotating electric machine 10, which serves to cool and lubricate the rotating electric machine 10. For this purpose, an oil pump 68 is provided as a fluid pump, which supplies a lubrication and cooling circuit 74 with oil. The oil flowing through the lubrication and cooling circuit 74 is collected in a reservoir 84 and returned to the oil pump 68.

[0053] Parallel to the lubrication and cooling circuit 74, an actuating circuit 76 is connected to the oil pump 68. The actuating circuit 76 can be activated by means of an electrical actuating signal (not shown), which in this case has two signal states: an actuating state and a rest state. These two signal states are represented by two corresponding voltage levels of the actuating signal. The actuating signal can be provided by a control device (not shown) by means of which the rotating electric machine 10 can be controlled.

[0054] The two signal states correspond to the two coupling states of the coupling unit 42, 48. The actuating circuit 76 is connected to a 1-2-way valve 78, which in turn is connected to a 1-2 piston-cylinder assembly 80 and to a 2-1 piston-cylinder assembly 82. Each of the two piston-cylinder assemblies 80, 82 is also connected to the reservoir 84. Pistons of the piston-cylinder assemblies 80, 82 (not shown) are mechanically connected to the actuator 32, so that, by actuating the piston-cylinder assemblies 80, 82, the actuator 32 can be actuated between two end positions, which correspond to the actuating positions of the coupling unit 42, 48.

[0055] The present arrangement provides that the actuating circuit 76 is activated by means of the electrical actuation signal, causing the oil to flow through the actuating circuit 76 to the directional control valve 78. The directional control valve 78 is coupled to the piston-cylinder assemblies 80, 82 such that it supplies oil to one of the respective piston-cylinder assemblies 80, 82, which moves the actuator 32 from one end position to the other. The oil supply causes the piston-cylinder assemblies 80, 82, which are coupled to each other, to change their positions and thus move the actuator 32 in the respective direction 62, 64. Upon subsequent actuation, the other piston-cylinder assemblies 80, 82 are supplied with oil, causing the actuator 32 to move in the opposite direction. This switches the clutch unit 42, 48 to their respective clutch states.The oil pump 68 is further coupled to the rotor lamination stack 26 via a gear unit 96. Therefore, an actuation signal only needs to act on the actuation circuit 76 during a switching operation.

[0056] The oil pump 68 is driven by an electric motor 98 via a gear arrangement 96 with a freewheel unit 88. The electric motor 98 can be operated in both directions of rotation, meaning it can be driven in either direction as needed. The gear arrangement 96 allows the speed of the electric motor 98 to be adjusted to a speed suitable for the oil pump 68. The freewheel unit 88 ensures that the oil pump 68 is driven only in one direction of rotation of the electric motor 98. The actuation signal, preferably the same, allows switching from one clutch state to the other clutch state of the clutch unit 42, 48.

[0057] Fig. Figure 10 shows a second embodiment for a fluid power drive unit 92, which is based on the embodiment of the fluid power drive unit 90. In contrast to the embodiment according to Fig. In this embodiment of the fluid power drive unit 92, a separate oil circuit is provided for actuating the actuator 32. For this purpose, the fluid power drive unit, which in this case is also a hydraulic drive unit 92, has a high-pressure oil pump 72 connected to the actuating circuit 76. The other elements correspond to those of the embodiment of the hydraulic drive unit 90, and reference is therefore made to the corresponding descriptions.

[0058] The high-pressure oil pump 72 is designed for a low flow rate at a high oil pressure. It is further connected via a freewheel 100 to a low-pressure oil pump 70, which is designed to deliver a high flow rate at a low oil pressure. The low-pressure oil pump 70 is, as described above, Fig. 9 already explained, connected to the electric motor 98.

[0059] The present embodiment is particularly suitable for a design in which the drive of the high-pressure oil pump 72 can be activated or deactivated by switching the direction of rotation of the electric motor 98. This ensures that the high-pressure oil pump 72 is only activated in one of the two directions of rotation of the rotor lamination stack 26.

[0060] The invention makes it fundamentally possible to easily integrate transmission and clutch functions into the rotating electric machine 10. Furthermore, the invention enables load-shifting capability, so that no noticeable interruption or reduction in traction occurs when changing gears. By integrating a load-shiftable, two-speed transmission into the installation space of the electric machine, a variety of electric drive solutions can be realized. Preferably, such an electric machine can be easily combined with existing transmissions in vehicle drives to further increase flexibility. Thus, the invention makes it possible, for example, to easily design electric vehicles for high speeds.In particular, with battery-electric vehicles such as electric vehicles, hybrid vehicles and the like, the subjective perception of a gear shift can be influenced by the fact that the electric drive exhibits more acceleration after the shift due to the reduction in engine speed during upshifting, while this acceleration usually decreases with a comparable combustion engine.

[0061] In electric vehicles or electrically powered vehicles, the requirements for comfort during gear changes are higher, since there are no masking noises and a rotating electric motor exhibits good torque-speed characteristics over a very wide speed range. The invention takes into account the fact that the rotating electric motor generally requires a transmission to reduce its advantageous speed level to a wheel speed.

[0062] For a gear ratio in a two-speed transmission, a value of approximately 1.5 can be considered a feasible and advantageous value, both with regard to achieving the widest possible speed range for the transmission's design and considering the acceptance of a reduction in traction during shifting. With a larger gear ratio, the acceptance of the traction loss may suffer, whereas with a smaller gear ratio, the advantage is minimal.

[0063] For the purposes of the invention, it is not necessary to distinguish between a load-shifting and a synchronous shifting system. The clutch unit can be implemented, as previously explained, for a load-shifting variant using appropriate actuators, for example, based on friction clutches. However, a positive-locking clutch, such as a dog clutch, can also be provided, as is the case, for example, with unsynchronized or synchronized manual or dual-clutch transmissions.

[0064] The invention particularly utilizes the available installation space as a feature, whereby the integration of at least one gear stage into the area radially located between the rotor shaft 24 and the winding heads 16 is provided. Possible gear ratios in a power flow reduction gearbox include a first gear providing a drive at the ring gear 56 and an output at the planet carrier 66, with the sun gear 58 clamped in place. A standard gear ratio can therefore be i = 1 - 1 / i0, resulting in an i0 of approximately -2.5. The second gear can then be a direct drive, as shown in the second embodiment. Fig. 5 and Fig. 6 was explained.

[0065] An alternative for a high-speed transmission could provide that the first gear is the direct drive and a second gear has a drive on the planet carrier 66, while an output is provided on the ring gear 56. Here too, the sun gear is fixed. The resulting gear ratio is i = i0 / (i0 - 1). A standard gear ratio might, for example, be approximately i0 = -2.0.

[0066] The schematic power transmission within the two-start electric machine 10 is independent of the type of clutch and its actuation. The following aspects are taken into account by the invention: - Bearing of the rotor lamination stack 26 of the rotor 40 on the rotor shaft 24, wherein a low-friction bearing enables a different rotational speed of the rotor lamination stack 26 and the rotor shaft 24; - comprehensive or at least partial integration of the power-carrying or power-converting elements or units in an area radially below the winding heads 16 of the rotating electrical machine 10; - Use of a rotation-maintaining arrangement of a planetary gear 46 for speed variation to both a higher speed and a lower speed of the rotor shaft 24; - Use of a rigid through-drive as a direct pass; - comprehensive or partial integration of an actuator 32 for at least one coupling element 42, 48 into the rotor shaft 24.

[0067] To implement load switching, two actuators are typically used to operate two friction clutches. In each of the two clutch states, only one of the actuators is actuated, while the other remains disengaged.

[0068] Furthermore, clutch units and brakes are typically designed as "normally open" systems. The invention enables a system to be achieved with just a single actuator, utilizing a "normally open" clutch with only one actuator acting in the same direction. The actuation strategy distinguishes between two states: a "natural state" and an "actuated state." Both states are designed to be structurally stable on a small scale. The distinction lies in the fact that reaching the "actuated state" requires a higher energy input and only needs to be geometrically stable on a small scale to a limited extent, whereas the "natural state" can be reached with less energy input and exhibits a wider stability range.

[0069] Natural State: This is activated during key-off operation and ensures continued operation even if the actuators fail. A speed or rotational speed limit may be necessary, but it allows the vehicle to be driven to the workshop or to continue operating until maintenance. - Actuator 32, as a "normally closed" system, holds one of the gears, preferably the first gear, engaged, regardless of the embodiment. In this state, no power consumption is required to maintain this state because a mechanical locking mechanism is present, for example by means of a detent element and / or a positive locking mechanism.

[0070] Actuated State: - A metastable configuration with mechanical locking via a purely force-fit or frictional connection. Disengagement occurs via a "small impulse" due to the metastable position, whereby the actuator force can be significantly lower than when engaging a gear. - The actuator maintains the "Normally Open" position in the second gear, whereby a metastable design can also function reliably without active actuation in the event of minor disturbances.

[0071] A mechanically based actuator system is feasible, however, a fluid-based, and in particular a hydraulic, actuator system is preferred in this case. The first embodiment according to the Fig. 3 and Fig. Figure 4 shows that the actuator 32 can be used to switch between the “Natural State” and the “Actuated State” by means of axial displacement.

[0072] In this case, the drive units 90, 92 are designed as hydraulic drive units. This means that only one drive unit is sufficient for the electric pump 68, 98, and only a simple switching valve is required to direct the pressurized flow into the respective chamber of the actuating cylinder 80, 82. From a design perspective, the actuating cylinder can be geometrically simplified; that is, instead of a conventional push / pull cylinder, two opposing simple pressure pistons in the form of piston-cylinder arrangements 80, 82 can be provided.

[0073] The selection of an operating mode for pump 68, 72 can be achieved via the direction of rotation of an electric drive motor 98 of the pump 68, 72 and a simple, automatically acting two-speed planetary gearbox 96. In one direction of rotation, the electric drive motor 98 drives the low-pressure oil pump 70 via a 1:1 gear ratio. This pump lubricates and cools integrated gear elements and the entire rotating electric machine 10 with a combined lubrication and cooling circuit 74. Due to the two switching positions and the compact, stable design of the actuator, no permanent cooling of the coupling elements 42, 48 is required, so a simple, unregulated drive control is sufficient for the pump drive.

[0074] In a different direction of rotation of the electric drive motor 98, the gearbox 96 can achieve a rotation-maintaining gear ratio at a high speed, thereby providing a higher oil flow rate for the duration of a switching operation. Thus, a purely mechanical solution eliminates the need for a controlled pump, enabling robust cooling and actuation of the actuator 32.

[0075] However, if the low-pressure oil pump 70 ( Fig. 9) If the provided oil pressure is insufficient for actuating the actuator 32, a parallel high-pressure oil pump 72 can also be driven via a simple freewheel 100 in the actuating direction of rotation of the pump drive in order to provide the necessary high actuating pressure ( Fig. 10).

[0076] Fig. Figure 10 shows the schematic structure of this more complex hydraulic control system, with dashed lines representing mechanical power flows and dotted lines representing hydraulic power flows.

[0077] In the Fig. 9 and Fig. 10 represents the “diode” symbol, a mechanically acting freewheel 88, 100, in which torque is transmitted in only one direction. Both in the design according to Fig. 9 as well as in the design according to Fig. 10 is provided that the pumps 68, 70, 72 are always driven in the same direction of rotation despite the changing direction of rotation of the electric motor 98.

[0078] According to the invention, the hydraulic drive unit 90, 92 is essentially based on the electric motor 98, at least one pump 68, 70, 72 and the hydraulic 1-2-way valve 78. The valve 78 directs the oil pressure provided by the oil pump 72 to the appropriate piston-cylinder arrangement 80, 82, depending on the switching operation, with which the clutch unit 42, 48 can be actuated analogously to a mechanical actuation.

[0079] The embodiments shown in the figures serve only to illustrate the invention and are not limiting to it. In particular, process features can also be provided for device features.

Claims

[1] Rotating electric machine (10) with: - a stator (12) having a winding head (16) at each axial end, - a rotor (40) rotatably mounted in an opening of the stand (12), which has a rotor shaft (24) and a rotor lamination stack (26), - a bearing unit (30) for rotatably supporting the rotor shaft (24) relative to the rotor lamination stack (26), - a gear unit (46), and - a coupling unit (42, 48) which is configured to provide at least two coupling states for rotationally coupling the rotor shaft (24) with the rotor lamination stack (26) and in at least one of the coupling states to couple the rotor shaft (24) with the rotor lamination stack (26) by means of the transmission unit (46), wherein the coupling unit (42, 48) has an actuator (32) arranged in the rotor shaft (24) and mounted to be displaceable in an axial direction of the rotor shaft (24) for actuating the coupling unit (42, 48). [2] Rotating electric machine according to claim 1, characterized by , that the coupling unit (42, 48) is designed in one of the coupling states for the direct rotational coupling of the rotor shaft (24) with the rotor lamination stack (26). [3] Rotating electric machine according to claim 1 or 2, characterized by, that the coupling unit (42, 48) is designed to automatically assume one of the predetermined coupling states. [4] Rotating electric machine according to claim 3, characterized by , that the coupling unit (42, 48) is designed to automatically assume the coupling state to be assumed depending on a direction of rotation of the rotor lamination stack (26). [5] Rotating electric machine according to any one of claims 1 to 4, characterized by , that the gear unit (46) has a planetary gear. [6] Rotating electric machine according to any one of claims 1 to 5, characterized by , that the transmission unit (46) and / or the clutch unit (42, 48) is arranged at least partially in an area extending between the rotor shaft (24) and at least one of the winding heads (16). [7] Rotating electric machine according to any one of the preceding claims, characterized bya fluid power drive unit (72, 76, 78, 80, 82) for driving the actuator (32). [8] Rotating electric machine according to claim 7, characterized by , that the fluid power drive unit (90, 92) comprises a fluid pump (72) that can be rotatably coupled to an electric motor (98). [9] Rotating electric machine according to claim 8, characterized by , that the fluid power drive unit (90, 92) is designed to decouple the fluid pump (72) from the electric motor (98) rotationally when the coupling state is automatically assumed. [10] Rotating electric machine according to claim 8 or 10, characterized by , that the fluid power drive unit (92) is designed to operate the fluid pump (72) exclusively during actuation of the clutch unit (42, 48). [11] Rotor (40) for a rotating electric machine (10) according to one of the preceding claims, characterized by, that the bearing unit (30), the gear unit (46), the clutch unit (42, 48) and / or the fluid power drive unit (90, 92) is formed integrally with the rotor (40).

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