Method for operating a motor vehicle transmission pump

Abstract

Method for operating a motor vehicle transmission pump (15) which is connected to an electric machine (1) by means of a summing gear (14) and which is connected or connectable to a drive unit (16) by means of the summing gear (14), wherein, to support the summing gear (14), the brake (6) is actuated at an actuation time (t1) at which a drive shaft (30) of the drive unit (16) has a minimum rotational speed (n1), characterized in that the rotational speed of the drive shaft (30) of the drive unit (16) is adjusted from a start time (t0) of the motor vehicle transmission pump (15) until the actuation time (t1) of the brake (6) and / or a rotational speed of a rotor shaft (9) of the electric machine (1) is adjusted from a start time (t0) of the motor vehicle transmission pump (15) until the actuation time (t1) of the brake (6) such thatthat the rotational speed of a pump shaft of the motor vehicle transmission pump (15) remains constant.

Description

[0001] The invention relates to a method for operating a motor vehicle gear pump which is drive-technically connected to an electric machine by means of a summing gear and which is drive-technically connected or connectable to a drive device by means of the summing gear.

[0002] Furthermore, the invention relates to a motor vehicle transmission with a control unit which is designed to carry out the method and to a motor vehicle with such a motor vehicle transmission.

[0003] A variety of motor vehicle transmissions are known from the prior art, which have a motor vehicle transmission pump arranged within a cavity of the motor vehicle transmission for pumping oil. It is known that the motor vehicle transmission pump can be driven by two separate drive devices. One drive device can comprise an internal combustion engine, an electric motor, or a hybrid drive, wherein the drive device is or can be connected to the motor vehicle transmission pump by means of a gear set and a summing gear. Another drive device can comprise another electric motor, which is connected to the motor vehicle transmission pump by means of the summing gear.

[0004] US 2004 / 0 112 654 A1 discloses a vibration damping device for reducing torsional resonance vibrations in a hybrid vehicle, the hybrid vehicle having an electric motor, an internal combustion engine and a transmission arrangement.

[0005] From DE 687 644 A an electric motor is known with an electromagnetically controlled brake arranged within the brake-side bearing plate which closes off the brake chamber to the outside, the control magnet of which is carried by a flange body which is attached to the hub of a normal bearing plate which receives the shaft bearings.

[0006] A disadvantage of the known designs is that when the motor vehicle transmission pump is operated solely by the drive unit, the electric motor is constantly dragged along. This generates a current in the electric motor that must be dissipated. Furthermore, the electric motor must be designed for the entire speed range of the drive unit.

[0007] The object of the invention is therefore to provide a method which enables the electric machine not to be driven even when the motor vehicle transmission pump is operated alone and which ensures an oil supply to the motor vehicle transmission.

[0008] The object is achieved by the method of the type mentioned at the outset, which is characterized in that, in order to support the summing gear by means of a brake, the brake is actuated at an actuation time at which a drive shaft of the drive device has a minimum speed.

[0009] The method according to the invention has the advantage that an oil supply to the motor vehicle transmission by the motor vehicle transmission pump is ensured at all times. In particular, the oil supply is also ensured when the drive shaft of the drive device does not have a high speed, so that if the motor vehicle transmission pump is driven solely by the drive device, the motor vehicle transmission pump cannot deliver the required oil volume flow. In these situations, the motor vehicle transmission pump is additionally or alternatively driven by the electric machine. The speed of the rotor shaft of the electric machine is selected to be high enough that a speed of the motor vehicle transmission pump is sufficiently high to deliver the oil volume flow required to supply the motor vehicle transmission. In this case, the motor vehicle transmission pump is motor-driven.

[0010] A further advantage is that by applying, in particular closing, the brake at the time of application, the electric motor can be prevented from being dragged. In particular, the electric motor does not need to be dragged if the speed of the drive shaft of the drive device is sufficiently high to achieve the speed of the motor vehicle transmission pump required to supply oil to the motor vehicle transmission. A further advantage is that freewheels are not required to prevent the electric motor from being dragged.

[0011] Furthermore, a further advantage of the invention is that the use of the brake makes it possible to suspend recuperation processes at times when no electrical consumers require electrical energy. Furthermore, the use of the brake makes it possible to disconnect the electrical branch in the event of a failure of the electric machine or its control system and to drive the motor vehicle transmission pump exclusively mechanically, in particular by means of the drive device. Furthermore, the electric machine can be immobilized at any time using the brake, regardless of whether it is operating in motor or electric mode.

[0012] The minimum speed of the drive shaft of the drive unit corresponds to the speed of the drive shaft at which the motor vehicle transmission pump operates at a sufficiently high speed so that the motor vehicle transmission pump can deliver the oil flow required to supply the motor vehicle transmission. Starting at the minimum speed, the motor vehicle transmission pump can be driven solely by the drive unit without the risk of the motor vehicle transmission pump delivering too low an oil flow. The minimum speed can have different values ​​for different operating conditions of the motor vehicle transmission pump, such as different torques and / or system pressures.

[0013] The drive device can comprise an internal combustion engine and / or another electric motor. The motor vehicle transmission pump serves to pump oil within the motor vehicle transmission.

[0014] The electric machine consists of at least a stator and a rotatably mounted rotor. During motor operation, it is designed to convert electrical energy into mechanical energy in the form of speed and torque. The rotor can be non-rotatably connected to a rotor shaft and / or attached to the rotor shaft.

[0015] The brake can be a switchable and / or mechanical brake. With a mechanical brake, the braking effect is achieved solely by mechanical components. In particular, the braking effect can be achieved by a coupling element, described in more detail below, and another coupling element. The brake can be switched to the open or closed state using an actuating device, described in more detail below.

[0016] The directions “axial” and “radial” refer to a central axis of the electrical machine, unless otherwise stated.

[0017] A shaft is not exclusively understood to mean, for example, a cylindrical, rotatably mounted machine element for transmitting torque, but rather also general connecting elements that connect individual components or elements to one another, in particular connecting elements that connect several elements to one another in a rotationally fixed manner.

[0018] The speed of the drive shaft of the drive device is adjusted from a starting point of the motor vehicle transmission pump until the brake is applied and / or the speed of the rotor shaft of the electric motor is adjusted from a starting point of the motor vehicle transmission pump until the brake is applied such that the speed of a pump shaft of the motor vehicle transmission pump remains constant. In particular, the speed of the rotor shaft of the electric motor can be adjusted to the speed of the drive shaft of the drive device. This is often necessary because the speed of the drive shaft of the drive device is specified by the vehicle manufacturer.As a result, by adjusting the speed of the rotor shaft and / or the speed of the drive shaft relative to each other, it can be achieved in a simple manner that the speed of the pump shaft of the motor vehicle transmission pump remains constant during operation of the motor vehicle transmission pump and thus the motor vehicle transmission pump can deliver an oil volume flow required for the oil supply.

[0019] The speed of the rotor shaft of the electric machine can be continuously reduced from a starting time of the motor vehicle transmission pump until the application time of the brake. In particular, the speed reduction can occur linearly. Furthermore, the speed of the drive shaft can be continuously increased from a starting time of the motor vehicle transmission pump until the application time of the brake. In particular, the speed increase can occur linearly. A drop in the speed of the rotor shaft can be linked to an increase in the speed of the drive shaft. As a result, by adjusting the speed of the rotor shaft of the electric machine and / or the speed of the drive shaft, it can be easily ensured that the speed of the motor vehicle transmission pump, in particular a pump shaft of the motor vehicle transmission pump, is constant.

[0020] The starting point is defined as the point in time at which the motor vehicle transmission pump is to deliver oil. The drive shaft cannot be rotating at the time the motor vehicle transmission pump starts. Therefore, the speed of the rotor shaft of the electric motors must be set high enough to ensure that the motor vehicle transmission pump delivers the required oil flow rate.

[0021] The brake can be designed such that, when the brake is applied, the brake prevents the rotor shaft of the electric machine from rotating at the time of application. When the brake is applied, the brake can be closed. However, the brake does not prevent the rotor shaft from rotating when the brake is not applied. In this case, the brake can be open.

[0022] In a special design, the brake can be switched to the closed or open state using an actuating device. The actuating device can be energized to apply the brake. Alternatively, the brake can be released when the actuating device is not energized. In particular, the actuating device cannot be energized if the drive shaft speed is lower than the minimum drive shaft speed. This provides a simple way to ensure that the speed of the motor vehicle transmission pump does not fall below a minimum value, thus ensuring the oil supply to the motor vehicle transmission.

[0023] The actuating means can be an electromagnet or comprise an electromagnet. Furthermore, the actuating means can comprise a coil, which can be wound with its own winding with two winding ends. The coil can be energized via the electronics of the electric machine. Energizing the actuating means can depend on a power limit of the electric machine, an on-board power system requirement of a motor vehicle in which the electric machine is installed, a power requirement of an internal transmission control system, and / or aspects for increasing availability or functional safety.

[0024] The actuating means can be offset from the stator and / or arranged within the cavity. In particular, the actuating means can be arranged axially offset from the stator and / or the rotor. The actuating means can have the same sheet metal cross-section as the stator. This allows for simple manufacturing of the actuating means. A portion of the actuating means, in particular the sheet metal cross-section, can be connected to the housing in a rotationally fixed manner. Furthermore, the actuating means can be energized independently of the stator.

[0025] The brake can have a coupling element that is movable relative to the rotor of the electric machine, wherein the brake is closed in a first position of the coupling element and opened in a second position of the coupling element. The coupling element can be connected to the rotor shaft in a rotationally fixed manner. Furthermore, the coupling element can be arranged so as to be movable in the axial direction relative to the rotor shaft and / or the rotor. The coupling element can be connected to the rotor shaft by means of a sliding toothing. Furthermore, the coupling element can be arranged coaxially to the rotor shaft. Furthermore, the coupling element can be arranged centrally to the actuating means in the first position.

[0026] A rotationally fixed connection is defined as a connection between two components that is designed and arranged in such a way that the two interconnected components always have the same rotational speed. This is not the case, for example, if a switching element is arranged between the two interconnected components and is in the open state.

[0027] The rotor shaft can extend through a housing of the electric machine. The housing can at least partially enclose a cavity in which the stator and / or the rotor are arranged. Furthermore, the rotor shaft can be supported on the housing, in particular directly, by means of at least one bearing. In particular, the rotor shaft can be supported on the housing, in particular directly, by means of exactly two bearings. The brake can be arranged within the cavity. Furthermore, the actuating means can be arranged within the cavity.

[0028] The brake can further comprise the other coupling element for a rotationally fixed connection to the coupling element. The other coupling element can be rotationally fixedly connected to the housing of the electric motor or the motor vehicle transmission. Furthermore, the other coupling element can be rotationally fixedly connected to the coupling element when the brake is engaged. The coupling element and the other coupling element can be connected to each other frictionally and / or positively. The rotationally fixed connection between the coupling element and the other coupling element can be realized independently of the direction of rotation of the rotor shaft.

[0029] The coupling element can move relative to the rotor shaft and / or the rotor when moving from the first position to the second position or vice versa. There is no axial movement of the rotor shaft and / or the rotor, which allows for a compact design of the electric machine. In particular, it is not necessary to provide space to accommodate the displaced rotor shaft and / or the displaced rotor. However, the rotor and / or the rotor shaft can rotate.

[0030] The brake can be engaged by moving the coupling element from the second position to the first position. Thus, apart from moving the coupling element from the second position to the first position, no further measures are necessary to create the rotationally fixed connection between the coupling element and the other coupling element. The brake can be released by moving the coupling element from the first position to the second position. Here, too, apart from moving the coupling element from the first position to the second position, no further measures are necessary to release the rotationally fixed connection between the coupling element and the other coupling element. As a result, the brake can be engaged or disengaged in a simple manner.

[0031] The coupling element can be actuated by the actuating means such that the coupling element moves from the first position to the second position. Alternatively or additionally, the coupling element can be actuated by the actuating means such that the coupling element moves from the second position to the first position. To actuate the coupling element by means of the actuating means, the actuating means can be energized. As a result of energizing the actuating means, an electromagnetic force is generated that acts on the coupling element and can cause the coupling element to move into the first and / or second position.

[0032] The electric machine can have a reset element that is operatively connected to the coupling element. The reset element can exert a force on the coupling element that is directed towards the second position. In particular, the reset element can be designed and arranged such that it moves the coupling element from the first position to the second position when the actuating means is not energized. The reset element can be designed as a spring, for example. The reset element can easily ensure that the rotor is moved into the second position when the actuating means is not energized. In contrast, when the actuating means is energized, the resulting electromagnetic force can be greater than the force applied by the reset element, so that the coupling element moves into the first position. When the rotor is moved into the first position, the reset element can be tensioned.

[0033] The return element can be supported at one end on the coupling element, in particular directly. Furthermore, the return element can be supported at another end, in particular indirectly, on the rotor shaft. In particular, the other end of the return element can be supported on the rotor shaft by means of a disk.

[0034] A motor vehicle transmission with a control unit designed to carry out a method according to the invention is advantageous. The motor vehicle transmission can have at least one gear set having at least two, in particular exactly two or three, gears. The drive device not belonging to the motor vehicle transmission can be drivingly connected or connectable to the summing gear by means of the gear set. The gears can be spur gears. In a design having two gears, the two gears can be in mesh with one another. In a design having three gears, an intermediate gear can be present that is in mesh with the two remaining gears.

[0035] Alternatively, the drive device can be connected to the summing gear via a traction drive or can be connected to it via a traction drive. The traction drive can comprise at least two gears and a traction mechanism, such as a chain. The two gears can be connected to each other via the traction mechanism.

[0036] The rotor shaft of the electric motor can be non-rotatably connected to a component of the summing gear. The component of the summing gear is mechanically supported by the rotor shaft when the brake is applied. In this case, the pump can be driven solely by the drive device, without the electric motor having to be dragged along. Furthermore, no axial forces are transmitted from the actuating means and / or the coupling element and / or the other coupling element to the rotor, or vice versa.

[0037] The drive device can be connected or connectable to another component of the summing gear. An output shaft of the summing gear can be connected in a rotationally fixed manner to another component of the summing gear. Furthermore, the output shaft can be connected in a rotationally fixed manner to the pump, in particular directly. In particular, the output shaft can be connected in a rotationally fixed manner to a pump shaft. The summing gear can have a planetary gear set.

[0038] The drive unit can be connected to the summing gear via the gear set. This is the case if a coupling is arranged between the drive unit and the gear set. Alternatively, the drive unit can be connected to the summing gear via the gear set if no coupling is arranged between the drive unit and the gear set.

[0039] The motor vehicle transmission may also include a gearbox. A gearbox input shaft of the gearbox may be connected to the gear set or the traction drive by means of a drive element, or may be connectable, for example, by means of a shifting element. The gearbox may have several other gear sets and / or several other shifting elements, by means of which different gears with different ratios can be implemented between the gearbox input shaft and a gearbox output shaft of the gearbox. The gearbox input shaft may be connected to the other gear sets by means of a drive element, or may be connectable by means of a drive element. Furthermore, the different gears can be implemented by engaging another shifting element or several other shifting elements.

[0040] Furthermore, a motor vehicle with the drive device and a motor vehicle transmission according to the invention is advantageous. The drive device can be connected to the motor vehicle transmission pump for driving purposes. In another motor vehicle, the drive device can be connected to the motor vehicle transmission pump for driving purposes by means of the clutch.

[0041] The subject matter of the invention is illustrated schematically in the figures and is described below with reference to the figures, wherein identical or equivalent elements are generally provided with the same reference numerals. Herein: Fig. 1 an electrical machine with a coupling element arranged in a first position, Fig. 2 the electric machine with the coupling element arranged in a second position, Fig. 3 an enlarged view of a section between the coupling element and an actuating means of the electrical machine, Fig. 4 a motor vehicle transmission according to the invention according to a first embodiment, Fig. 5 a motor vehicle transmission according to the invention according to a second embodiment. Fig. 6 a speed curve of the electric machine, the drive shaft and the motor vehicle transmission pump,

[0042] Fig. Figure 1 shows an electrical machine 1 with a stator 3, a housing 4, which partially encloses a cavity 5, and a rotor 2. The stator 3 and the rotor 2 are arranged within the cavity 5. The rotor 2 is connected to a rotor shaft 9 for driving purposes. In particular, the rotor 2 is connected to the rotor shaft 9 in a rotationally fixed manner. Fig. 1 only an upper part of the electrical machine 1.

[0043] A brake 6 is arranged within the cavity 5. The brake 6 has a coupling element 7, which is connected to the rotor shaft 9 by means of a sliding toothing 19 in such a way that the coupling element 7 is movable in the axial direction with respect to a central axis 20 of the electric machine 1 relative to the rotor shaft 9 and the rotor 2. In addition, the coupling element 7 is connected to the rotor shaft 9 in a rotationally fixed manner. In a first position of the coupling element 7, the brake 6 is closed. In a second position of the coupling element 7, the brake 6 is opened. The rotor shaft 9 is connected to a Fig. 4 shown summing gear 14.

[0044] The stator 3 is arranged further away in the radial direction from the central axis 20 than the rotor 2. The stator 3 is connected to the housing 4 in a rotationally fixed manner. The stator 3 and the rotor 2 are arranged and designed such that they cannot move along the central axis 20. The rotor shaft 9 cannot move along the central axis 20 either.

[0045] When the brake 6 is in the closed switching state, Fig. 1, the coupling element 7 is connected in a rotationally fixed manner to another coupling element 8 of the brake 6. The other coupling element 8 is connected in a rotationally fixed manner to the housing 4 and / or is formed integrally with the housing 4. When the brake 6 is in the closed switching state, the rotor shaft 9 and thus the rotor 2 cannot rotate. Thus, Fig. 4 visible summing gear 14 resulting torques are supported by means of the rotor shaft 9, the coupling element 7, the other coupling element 8 and the housing 4.

[0046] The electric machine 1 has an actuating means 11 in the form of an electromagnet, which is arranged in the cavity 5. The actuating means 11 is arranged offset in the axial direction to the stator 3. Furthermore, a part of the actuating means 11 is connected to the housing 4 in a rotationally fixed manner. Fig. In the state of the electrical machine 1 shown in Figure 1, the electrical machine 1, in particular the actuating means 11 of the electrical machine 1, is energized. The electromagnetic force resulting from the energization holds the coupling element 7 in the first position.

[0047] The rotor shaft 9 is supported on the housing 4 via two bearings 10. Furthermore, the rotor shaft 9 extends through the housing 4. In particular, the end of the rotor shaft 9 extends through the housing 4, which is rotationally fixedly connected to a component of the summing gear 14.

[0048] The electric machine 1 has a return element 12. The return element 12 is designed as a spring, which is supported at one end on the coupling element 7. In the Fig. In the state of the electrical machine 1 shown in Figure 1, the reset element 12 is tensioned. The reset element 12 is supported at the other end on a disc 21.

[0049] Fig. Figure 2 shows the electric machine 1 with the coupling element 7 arranged in a second position. In the second position, the coupling element 7 is no longer rotationally fixedly connected to the other coupling element 8. This means that the brake 6 is in an open state. The return element 12 presses the coupling element 7 out of the Fig. 1 shown first position into the one shown in Fig. 2. When transferred from the first position to the second position, the coupling element 7 moves in a direction away from the other coupling element 8. In the second position, the electric machine 1 can be motor-driven. To move the coupling element 7 from the first position to the second position, the actuating means 11 is no longer energized, so that no electromagnetic force acts on the coupling element 7 that is greater than the force exerted on the coupling element 7 by the return element 12.

[0050] Fig. 3 shows an enlarged view of a Fig. 2 shown section A between the actuating means 11 and the coupling element 7. From Fig. 3 shows the course of magnetic field lines 35 between the actuating means 11 and the coupling element 7. In addition, Fig. Figure 3 shows the progression of a force 36 acting on the coupling element 7. The force 36 has an axial and a radial component.

[0051] When the actuating means 11 is not energized, the spring force exerted by the return element 12 on the coupling element 7 is large enough to move the coupling element 7 from the first position to the second position. When the actuating means 11 is energized, the axial component of the force 36 is greater than the spring force of the return element 12, so that the coupling element 7 moves from the second position to the Fig. 1 shown first position.

[0052] Fig. 4 shows a motor vehicle transmission 13 according to a first exemplary embodiment. The motor vehicle transmission 13 has the electric machine 1, which is drivingly connected to the motor vehicle transmission pump 15 by means of the summing gear 14. The motor vehicle transmission pump 15, in particular a pump shaft of the motor vehicle transmission pump 15, is drivingly connected to the output shaft 23 of the summing gear 14. The summing gear 14 is also drivingly connectable to a drive device 16 by means of a gear set 17. In particular, a drive shaft 30 of the drive device 16 is rotationally fixedly connected to the summing gear 14 by means of a coupling 24.

[0053] The gear set 17 has a first gear 25, an intermediate gear 26, and a second gear 27. The first gear 25 meshes with the intermediate gear 26. The intermediate gear 26 also meshes with the second gear 27. The second gear 27 is directly connected to the summing gear 14. Furthermore, the second gear 27 is supported by a bearing on a housing G of the motor vehicle transmission 13. The summing gear 14 can have a planetary gear set (not shown in the figures). In this case, the rotor shaft 9 is rotationally fixedly connected to one component of the planetary gear set, in particular a sun gear. The second gear 27 is rotationally fixedly connected to another component of the planetary gear set, in particular a ring gear. The output shaft 23 is rotationally fixedly connected to another component of the planetary gear set, in particular a carrier.

[0054] The motor vehicle transmission 13 also has a gear 28. The transmission 28 has several other gear sets and / or other shifting elements (not shown in the figures) for implementing different gears with different ratios. The first gear 25 is rotationally fixedly connected to a transmission input shaft 29 of the transmission 28. The transmission input shaft 29 can also be rotationally fixedly connected to the drive shaft 30 by means of the clutch 24.

[0055] The motor vehicle transmission pump 15 can be driven by the drive device 16 alone. In this case, the coupling element 7 is arranged in the second position. Furthermore, the motor vehicle transmission pump 15 can be operated jointly by the drive device 16 and the electric machine 1 or solely by the electric machine 1. The motor vehicle transmission 13 and the drive device 16 can be part of a motor vehicle 18.

[0056] Fig. 5 shows a motor vehicle transmission 13 according to a second embodiment. The motor vehicle transmission 13 according to the second embodiment differs from that shown in Fig. 4 in the design of the gear set 17. The gear set 17 differs in that there is no intermediate gear 26. This means that the first gear 25 is in mesh with the second gear 27.

[0057] Fig. 6 shows a speed curve 31 of the electric machine 1, a speed curve 32 of the drive shaft 30 of the drive device 16 and a speed curve 33 of the motor vehicle transmission pump 15, in particular the pump shaft of the motor vehicle transmission pump 15, over time t. In addition, in Fig. 6 shows a minimum speed 34 of the motor vehicle transmission pump 15, which is required for the motor vehicle transmission pump 15 to deliver the oil volume flow required for supplying the motor vehicle transmission 13. The speed n is plotted vertically, and the time t is plotted horizontally.

[0058] As from Fig. 6, the brake 6 is closed at an actuation time t1. From the actuation time t1, the rotor shaft 9 of the electric machine 1 no longer rotates. At the actuation time t1, the speed of the drive shaft 30 corresponds to a minimum speed n1. The minimum speed n1 has such a high value that a speed of the motor vehicle transmission pump 15 is established at which a sufficiently high oil volume flow can be pumped through the motor vehicle transmission pump 15 to supply the motor vehicle transmission 13 with oil.

[0059] At a starting time t0, only the rotor shaft 9 of the electric machine 1 has a speed greater than zero. The speed of the rotor shaft 9 is so high that a speed of the motor vehicle transmission pump 15 is established that is sufficient to supply oil to the motor vehicle transmission 13. The speed of the rotor shaft 9 of the electric machine 1 decreases linearly from the starting time t0 to the actuation time t1. In contrast, the speed of the drive shaft 30 increases linearly from the starting time t0 from a value of zero to the minimum speed n1 at the actuation time t1. The speed of the electric machine 1 decreases and the speed of the drive shaft 30 increases such that the motor vehicle transmission pump 15 has a constant speed. The electric machine 1 is operated as a motor between the starting time t0 and the actuation time t1.From the actuation time t1, the speed of the motor vehicle transmission pump 15 increases and the rotor shaft 9 does not rotate. Reference symbol 1 electric machine 2 rotors 3 Stator 4 Housing of the electrical machine 5 Cavity 6 Brake 7 Coupling element 8 other coupling element 9 Rotor shaft 10 warehouses 11 Actuating means 12 Reset element 13 Motor vehicle transmissions 14 summing gears 15 Automotive transmission pump 16 Drive device 17 wheelset 18 Motor vehicle 19 Sliding gearing 20 Central axis 21 disc 23 Output shaft 24 Clutch 25 first gear 26 intermediate gear 27 second gear 28 gearboxes 29 Gearbox input shaft 30 drive shaft 31 Speed ​​curve of the rotor shaft of the electric machine, 32 Speed ​​curve of the drive shaft of the drive device 33 Speed ​​curve of the automotive transmission pump 34 Minimum speed of the motor vehicle transmission pump 35 magnetic field lines 36 Force Section A G Housing of the motor vehicle gearbox n speed t time n1 Minimum speed t0 start time t1 Actuation time

Claims

[1] Method for operating a motor vehicle gear pump (15) which is drive-technically connected to an electric machine (1) by means of a summing gear (14) and which is drive-technically connected or connectable to a drive device (16) by means of the summing gear (14), wherein, in order to support the summing gear (14), the brake (6) is actuated by means of a brake (6) at an actuation time (t1) at which a drive shaft (30) of the drive device (16) has a minimum speed (n1), characterized bythat the rotational speed of the drive shaft (30) of the drive device (16) from a starting time (t0) of the motor vehicle transmission pump (15) to the actuation time (t1) of the brake (6) and / or a rotational speed of a rotor shaft (9) of the electric machine (1) from a starting time (t0) of the motor vehicle transmission pump (15) to the actuation time (t1) of the brake (6) are set in such a way that a rotational speed of a pump shaft of the motor vehicle transmission pump (15) remains constant. [2] Method according to claim 1, characterized by , that a. when the brake (6) is actuated at the actuation time (t1), rotation of a rotor shaft (9) of the electrical machine (1) is prevented by means of the brake (6) and / or that b. when the brake (6) is actuated at the actuation time (t1), the brake (6) is closed. [3] Method according to one of claims 1 and 2, characterized bythat the brake (6) is switched into a closed switching state or an open switching state by means of an actuating means (11). [4] Method according to claim 3, characterized by that the actuating means (11) a. is energized to close the brake (6) and / or b. no current is supplied to open the brake (6). [5] Method according to claim 3 or 4, characterized by that the actuating means (11) is not energized if the speed of the drive shaft (30) is lower than the minimum speed (n1) of the drive shaft (30). [6] Motor vehicle transmission (13) with a control unit designed to carry out a method according to one of claims 1 to 5. [7] Motor vehicle transmission (13) according to claim 6, characterized byin that the brake (6) has a coupling element (7) which is movable relative to a rotor (2) of the electrical machine (1), wherein in a first position of the coupling element (7) the brake (6) is closed and in a second position of the coupling element (7) the brake (6) is opened. [8] Motor vehicle transmission (13) according to claim 7, characterized by , that a. the coupling element (7) is connected to the rotor shaft (9) in a rotationally fixed manner and / or that b. the coupling element (7) is movable in the axial direction relative to the rotor shaft (9) and / or the rotor (2) and / or that c. the coupling element (7) is arranged coaxially to the rotor shaft (9). [9] Motor vehicle transmission (13) according to claim 7 or 8, characterized by that the brake (6) has another coupling element (8) which a. is connected to a housing (4) in a rotationally fixed manner and / or the b. is connected to the coupling element (7) in a rotationally fixed manner when the brake (6) is closed. [10] Motor vehicle transmission (13) according to one of claims 8 to 9, characterized by a return element (12) which is operatively connected to the coupling element (7) and which moves the coupling element (7) from the first position to the second position. [11] Motor vehicle transmission (13) according to one of claims 6 to 10, characterized by , that a. the actuating means (11) is arranged offset to a stator (3) of the electrical machine (1) and / or that b. the actuating means (11) can be energized independently of the stator (3). [12] Motor vehicle (18) with the drive device (16) and a motor vehicle transmission (13) according to one of claims 6 to 11, characterized by , that a. the drive device (16) is connected to the motor vehicle transmission pump (15) or that b. the drive device (16) can be connected to the motor vehicle transmission pump (15) by means of a coupling (24).

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