Method, computer program, computer program product, system and vehicle for positioning rotor shaft of electric machine

Abstract

The invention relates to a method for positioning a rotor shaft (RW) of an electric machine, comprising the following steps: determining an initial position of the rotor shaft (RW) from a plurality of definable rotational angular positions of the rotor shaft (RW), in which rotational angular positions the rotor shaft (RW) can be locked or unlocked without positive restraint by means of a form-locking element (FE) of a locking actuator (SA), in order to determine the initial position, the rotor shaft (RW) is divided on the circumference thereof into individual arc sections in such a way that each of the arc sections is assigned a form-fitting section which can engage with a form-fitting section of the locking actuator (SA), which form-fitting section is complementary to the form-fitting section. The rotor shaft (RW) is positioned in one of the rotational angular positions, an absolute rotational angular position of the rotor shaft (RW) is detected by means of a rotor (shaft) position sensor, and the rotor shaft (RW) is locked or unlocked in the rotational angular position by moving the form fitting (FE) into the rotor shaft (RW) or out of the rotor shaft (RW) during a stroke movement. The invention also relates to a computer program, a computer program product, a system and a vehicle.

Description

Technical Field

[0001] The present invention relates to a method for positioning the rotor shaft of an electric motor, particularly for driving a vehicle.

[0002] The present invention further relates to: a computer program and a computer program product, each implementing the method; a system having a locking actuator and a control unit connected to the locking actuator, wherein the control unit has such a computer program or computer program product; and a vehicle having such a computer program or computer program product. Background Technology

[0003] Parking locks are known in which an electrically actuated lever interacts with gears in the powertrain via so-called ratchet teeth to lock or engage the powertrain. For example, reference DE 10 2017 102 804 A1 describes such a parking lock with a ratchet mechanism.

[0004] Parking locks with locking mechanisms or locking elements that can be adjusted or moved linearly along a movement trajectory are also known. For example, reference DE 10 2019 110 384 A1 describes such a parking lock with a locking bolt. Summary of the Invention

[0005] The purpose of this invention is to improve the locking and unlocking of this parking lock.

[0006] This objective is achieved by the method claimed in claim 1 and which is protected.

[0007] A method for locating the rotor shaft of an electric motor, particularly for driving a vehicle, is proposed herein, comprising the following steps:

[0008] - The initial position of the rotor shaft is determined by multiple definable rotational angular positions, where the rotor shaft can be locked or unlocked in a manner free from forced constraints, stress, and jamming by means of the locking actuator's form-locking mechanism.

[0009] To determine this initial position, the rotor shaft is divided into individual arc segments on its circumference, such that each of these arc segments is assigned a form-locking segment that can engage with a complementary form-locking segment of the locking actuator.

[0010] - Position the rotor shaft to one of these rotational angular positions, wherein the absolute rotational angular position of the rotor shaft is detected by means of a rotor (shaft) position sensor, and

[0011] - Locking or unlocking the rotor shaft at this rotational angular position is achieved by moving the form-locking element into or out of the rotor shaft during a stroke / linear motion (Hubbewegung).

[0012] By means of a so-called rotor (shaft) position sensor, the position or state of the motor rotor relative to the three phases or poles of the motor stator can be accurately determined, and thus the position or state of the rotor shaft—on which the rotor is mounted—relative to the three phases or poles of the motor stator can be accurately determined. The rotor (shaft) position sensor thus enables efficient commutation of the motor and provides the absolute angular position of the rotor shaft.

[0013] The rotor (shaft) position sensor can be implemented here in the form of an inductive signal generator or a Hall sensor, the function of which is well known to those skilled in the art. The rotor (shaft) position sensor can be located on the motor side or on the vehicle drive side, that is, on the power equipment of the vehicle designed as an electric motor, or it can be located on the locking actuator side, that is, on the locking actuator.

[0014] The initial position of the rotor shaft can be understood as an ideal rotational angular position or ideal position of the rotor shaft relative to the form-locking element of the locking actuator. That is, it is an ideal rotational angular position or ideal position among a plurality of definable ideal rotational angular positions or ideal positions of the rotor shaft. In this ideal rotational angular position or ideal position, the rotor shaft is positioned or oriented relative to the form-locking element, so that the rotor shaft can be locked or unlocked in a manner without forced constraints by means of the form-locking element of the locking actuator.

[0015] "No mandatory constraint" here means that two interlocking parts that act together are engaged or aligned without contact with each other, provided that their respective tooth sides / sides in the circumferential direction of the rotor shaft or locking actuator do not contact or do not contact each other.

[0016] Based on this—one-time determined—initial position, the rotor shaft is definitively divided into the arc segments on its circumference, and considering the current, accurately detected rotational angular position of the rotor shaft, the rotor shaft can rotate or move to a corresponding ideal position. This so-called ideal position refers to the support locations, which are stored in the software or computer program of the control unit used to drive or rotate the rotor shaft.

[0017] Therefore, the proposed method enables the locking or unlocking of the rotor shaft via the form-locking components of the locking actuator in a non-constrained manner. This is because the two interacting form-locking component segments are positioned or oriented relative to each other for the purpose of locking or unlocking the rotor shaft, such that the tooth sides of the form-locking component segments do not contact each other in the circumferential direction of the rotor shaft or the locking actuator. Form-locking between the two form-locking component segments is thus achieved without tooth side contact, or disengagement occurs without tooth side contact. Therefore, from the perspective of the locking actuator, locking or unlocking can be performed in a force-optimized manner, i.e., with minimal force consumption.

[0018] The force-optimized drive method of the locking actuator can achieve the following: the locking actuator can be implemented in a sufficiently robust manner while being as small or very compact as possible, that is, the locking actuator can be implemented cost-effectively and with weight savings. Along with this, the assembly cost of such locking actuators is also reduced.

[0019] It is proposed here that, when adopting the ideal rotation angle position, there should be no relative angle between or between the two interacting locking parts. That is, the two locking parts are arranged or placed relatively centered on each other in the circumferential direction of the rotor shaft or locking actuator.

[0020] Alternatively, an ideal rotational angular position can be applied where the two interacting locking segments form an angle relative to each other, resulting in an eccentric arrangement of these segments in the circumferential direction of the rotor shaft or locking actuator, provided that the tooth sides of the locking segments do not contact in the circumferential direction of the rotor shaft or locking actuator. A mechanical clearance is correspondingly provided between the two locking segments in the circumferential direction of the rotor shaft or locking actuator. This mechanical clearance—by design—allows for multiple possible positions of the two interacting locking segments in which no contact occurs between the tooth sides.

[0021] It is proposed here that uniform indexing (Teilung) be used to divide the circumference of the rotor shaft. This simplifies the positioning of the rotor shaft based on the one-time determined and fixed initial position.

[0022] One embodiment proposes a locking mechanism in which a form-locking member moves along the rotor shaft in an axial stroke / axial linear motion toward the rotor shaft. This can be achieved by using a rotor shaft with external teeth in the end region and a complementary form-locking member that moves in the axial stroke and along the rotor shaft in a manner toward and into the rotor shaft.

[0023] The proposed method can be used to fix a vehicle. It is proposed that, after the form-locking member is moved into the rotor shaft without forced constraint, the rotor shaft is stopped relative to the form-locking member in a clockwise or counterclockwise direction, so that the rotor shaft is tensioned / clamped relative to the form-locking member. The rotor shaft can be stopped relative to the form-locking member until a limited electric shut-off torque of the motor is reached, at which point the rotation of the rotor shaft is interrupted.

[0024] The motor's shut-off torque corresponds to the motor's monitorable current consumption, thereby shutting off the motor or interrupting the rotation of the rotor shaft when a defined reference value for current consumption is reached.

[0025] The intentionally induced tension creates effective tamper protection that prevents or at least significantly increases the difficulty of unlocking the locking actuator by a third party or unauthorized person. In an attempt to tamper with the locking actuator in the tensioned state during testing, for example by trying to apply current to the actuator, the force generated on the actuator would be insufficient for the unlocking process.

[0026] The proposed method can also be used to relax a rotor shaft that is stopped and tensioned relative to a form-locking member due to load. Here, the rotor shaft is positioned at a rotation angle in which it is locked without forced constraint beforehand, so as to relax the rotor shaft, and then the form-locking member is removed from the rotor shaft without forced constraint.

[0027] The rotor shaft experiences tension due to load, such as when a vehicle is parked in an inclined position, for example, due to a curb, where the vehicle can only be parked with one tire supported. In this case, the powertrain is tensioned in the locked state of the locking actuator because the vehicle is supported by the actuator. In this position, compared to when the vehicle is parked on a flat surface, a greater unlocking force is required to unlock the actuator.

[0028] Consider, for example, a parking situation where the vehicle is parked on a slope or ramp. In such a case, the vehicle is also supported by the parking lock due to the downhill force acting on it, which causes the vehicle to move.

[0029] Furthermore, a computer program and computer program product for implementing the aforementioned method are proposed. The computer program and computer program product include a program code tool stored on a computer-readable data carrier so that the aforementioned method can be implemented when the program code tool is executed on a computer.

[0030] Furthermore, a system is proposed that includes a locking actuator and a control unit connected to the locking actuator, wherein the control unit has a computer program or computer program product of the aforementioned type. Additionally, a vehicle is proposed that has a computer program or computer program product of the aforementioned type.

[0031] Vehicles here can be understood as any type of vehicle or motor vehicle that is powered by an electric motor, particularly passenger cars and / or commercial vehicles in the form of electric or hybrid vehicles. This may include vehicles that operate partially or fully autonomously. Attached Figure Description

[0032] The attached diagram schematically illustrates:

[0033] Figure 1 This illustrates the setup for locking the rotor shaft of the actuator and motor.

[0034] Figure 2 An inverter with a control unit and an inverter with a control unit are shown. Figure 1 The system diagram of the locking actuator shown in the figure is as follows.

[0035] Figure 3 Shown in Figure 1 The locking process of the locking mechanism shown in the figure, and

[0036] Figure 4 Shown in Figure 1 The unlocking process of the locking mechanism is shown in the figure. Detailed Implementation

[0037] according to Figure 1 The locking mechanism described herein comprises two complementary and rotatable shaped locking elements: a first shaped locking element FE of the locking actuator SA and a second shaped locking element in the form of a lockable rotor shaft RW for driving a motor (not shown) of a vehicle. The locking actuator SA is mounted on, and thus supported on, the housing (not shown) of the motor of the motor drive unit—which itself may include a transmission. Depending on the state of the locking mechanism, the two shaped locking elements FE and RW are arranged coaxially (unlocked state) or partially concentrically (locked state).

[0038] In this case, the internal toothed portion IV of the shaped locking member FE works together with the external toothed portion AV of the rotor shaft RW, which is itself formed in the end region of the rotor shaft RW. The method is to electrically drive the shaped locking member FE during axial travel and along the direction of the rotor shaft RW, where it partially engages with the end of the rotor shaft.

[0039] The vehicle including the locking mechanism has: a motor drive unit comprising a motor in the form of a permanent magnet synchronous motor or a separately excited synchronous motor for driving the vehicle, wherein the motor may be combined with a reduction gear if necessary; a high-voltage battery; and an inverter / converter included in the vehicle's power electronics, which establishes a connection between the motor and the high-voltage battery. The power electronics may optionally include an integrated voltage converter that supplies power from the vehicle's high-voltage on-grid to the vehicle's low-voltage on-grid.

[0040] The inverter's control unit controls, regulates, and monitors the motor, providing the required torque and speed control for the vehicle's powertrain. Furthermore, the inverter converts the DC voltage from the high-voltage battery into the AC voltage required by the motor.

[0041] The power electronics, or the inverters comprising the power electronics, not only power the motor but also the high-voltage battery, i.e., when the motor operates as a generator and feeds current into the high-voltage battery. In this process, known as recycling, the power electronics convert the alternating current generated by the motor into direct current, thereby charging the high-voltage battery.

[0042] Figure 2 Explain the control unit SE in the inverter or the inverter itself. Inv With the locking actuator or the locking actuator's own control unit SE SA System connections between them. Control unit SE Inv Here, based on the vehicle's input parameter FP (FP = vehicle parameter), the control unit SE is notified. SA The output control command SB is followed by locking or locking the actuator SA, or unlocking or releasing the rotor shaft RW. In the control unit SE... SA The actuator status AZ and the locked status, or locked state VZ, are displayed or output.

[0043] Figure 3 The arrangement of the internal toothed portion IV of the form-locking member FE and the external toothed portion AV of the rotor shaft RW in the unfolded state is explained, that is, with reference to the circumferential and longitudinal directions of the two form-locking members FE and RW. The internal toothed portion IV is fixed in position relative to the circumferential direction of the two form-locking members FE and RW, while the external toothed portion AV can rotate relative to the internal toothed portion IV.

[0044] In this design, both the locking element FE and the rotor shaft RW can be divided into uniform arc segments (arc segment = 360° / n; n = number of teeth) on their respective circumferences according to a defined distribution, and these arc segments therefore all have the same angular range.

[0045] According to Figure 3In the unfolded view, the angular range of such an arc segment is represented by the segment length SL. Relative to the center point of the locking member FE or the center point of the rotor shaft RW, this angular range corresponds to the arc-shaped spacing formed by indexing between the centers of two adjacent teeth in the internal tooth section IV or between the centers of two adjacent tooth gaps in the external tooth section AV.

[0046] according to Figure 3 The segment length SL—expressed in degrees (angles)—describes the step width from one ideal orientation of the two form-locking parts FE, RW to the next ideal orientation, wherein the corresponding segment lengths SL in the ideal orientation have no or no angular deviation from each other. That is, these corresponding segment lengths SL coincide precisely with each other, and therefore do not offset or deviate from each other in the circumferential direction of the two form-locking parts FE, RW.

[0047] The ideal orientation between the two locking parts FE and RW is determined by the internal toothed part IV and the external toothed part AV. Figure 3 The arrangement shown at the top is illustrated. In this arrangement, the two form-locking members FE and RW are not engaged with each other. The locking mechanism formed by the two form-locking members FE and RW is in an unlocked or released state. In the rotational direction of the rotor shaft RW, one of these ideal orientations is here suitable to be determined as the initial position or initial state in which the two form-locking members FE and RW are engaged with each other without contact on their respective toothed sides, and thus in a force-optimal manner without forced constraint, and therefore from the perspective of the locking actuator SA.

[0048] Knowing this initially determined position, the rotor shaft RW can be rotated to the corresponding ideal orientation or a rotation angle position corresponding to the ideal orientation according to the determined indexing, that is, according to the number of arc segments (given by...). Figure 3 (The arrangement in the second-to-last line is explained). The number of these arc segments is limited by the number of teeth. Here, the absolute rotational angular position of the rotor shaft RW is accurately detected by means of a rotor (shaft) position sensor.

[0049] This allows the periphery of the two locking members FE and RW to be divided into, for example, n = 32 (because each has 32 teeth) circular arc segments, resulting in uniform circular arc segments of 360° / 32 = 11.25°. The ideal orientation of the rotor shaft RW, or the rotational angular position corresponding to that ideal orientation, thus represents the support locations, which are themselves stored in the control unit SE. Inv It can also be moved to these support parts.

[0050] exist Figure 3The second and third arrangements of the internal toothed portion IV and the external toothed portion AV shown in the figure each illustrate deviations Abw. 01 and Abw. 02 between the allocated segment lengths SL, wherein these deviations Abw. 01 and Abw. 02 cause the locking mechanism to fail to form a form lock.

[0051] In the parking situation, where the vehicle is stopped and locked, the rotor shaft RW can be rotated in a first rotational direction and a second rotational direction opposite to it, or clockwise or counterclockwise, to one of the desired orientations.

[0052] Here, the rotor shaft RW can be rotated to the nearest ideal orientation or to the next support position based on the shortest path, that is, rotated to the ideal orientation that forms the minimum angle or minimum angular difference with the currently detected absolute rotation angle position of the rotor shaft RW, provided that environmental conditions permit. Therefore, the rotor shaft RW is rotated by this detected angular difference until it reaches the corresponding support position.

[0053] exist Figure 3 The penultimate arrangement shown illustrates this ideal orientation of the rotor shaft RW relative to the form-locking member FE, in the inverter control unit SE. Inv Control unit SE of the directional locking actuator SA A The output is a control command SB for locking the rotor shaft RW, and then the form-locking member FE is electrically driven or moved toward the rotor shaft RW while the vehicle is stationary (vehicle speed = 0 km / h). Here, the form-locking member FE is moved into the rotor shaft RW in a force-optimal manner without forced constraints, that is, without contact between the corresponding tooth sides, and therefore from the perspective of the locking actuator SA.

[0054] exist Figure 3 The locking mechanism's form-locking is explained in the last or bottommost arrangement. In this form-locking arrangement, the two locking elements FE and RW are slightly misaligned due to the gap. That is, the corresponding arc segments of the two locking elements FE and RW are no longer precisely aligned with each other.

[0055] In comparison Figure 4 Clarify based on Figure 4 The uppermost arrangement shown illustrates the unlocking or release of the locking mechanism, specifying its locked or locked state. Specifically, this uppermost arrangement specifies a state where the external tooth AV stops relative to the internal tooth IV. The arrangement also specifies the deviation Abw. 03 between their respective segment lengths SL.

[0056] This may be caused by the following: the vehicle is parked unevenly, causing it to lean against the locking actuator SA and thus against the motor housing. This, in turn, causes tension on the rotor shaft RW relative to the form-locking member FE.

[0057] This tension of the rotor shaft RW relative to the form-locking member FE may also be due to: after the rotor shaft is locked without forced constraint by the form-locking member FE, the rotor shaft RW is stopped clockwise or counterclockwise relative to the form-locking member FE, so that the rotor shaft RW is tensioned relative to the form-locking member FE. This ensures that tampering by third parties or unauthorized persons is prevented, thereby prohibiting the unlocking of the locking actuator or at least significantly increasing the difficulty of unlocking.

[0058] During the vehicle commissioning process, in the control unit SE A The device displays the locked state VZ and outputs this locked state to the control unit SE. Inv Control Unit SE Inv The control command SB, used to unlock the rotor shaft RW, is output to the control unit SE. A Next, the rotor shaft RW—with the vehicle stationary (vehicle speed = 0 km / h) and with the accurate detected absolute position or absolute state of the rotor shaft RW known—is positioned at a rotational angular position in which the rotor shaft is pre-locked, and where the currently detected absolute rotational angular position of the rotor shaft RW forms an angle or angular difference with this position, so as to relax the rotor shaft RW. The rotor shaft RW then rotates with this angular difference to the finally reached support position.

[0059] Next, the form-locking member FE is moved from the rotor shaft RW in a manner without forced constraint, that is, without contact between their respective tooth sides, and therefore from the perspective of the locking actuator SA, with optimized force, thereby releasing the form-locking of the locking mechanism. The vehicle can then be moved.

[0060] according to Figure 4 The deviation Abw. 03 here is due not only to the clearance, that is, not only to the mechanical clearance between the form-locking member FE and the rotor shaft RW in the circumferential direction of the locking actuator SA, but also to the elasticity on which the locking mechanism is based. This elasticity causes the corresponding position of the rotor shaft RW relative to the form-locking member FE due to the load formed acting on the locking mechanism. The elasticity here is related to the configuration of the two form-locking members FE and RW.

[0061] However, this type of deviation Abw. 03—where the rotor shaft RW is tensioned relative to the form-locking member FE—can also arise solely from the elasticity upon which the locking mechanism is based, where the deviation Abw. 03 is generated in conjunction with the load acting on the locking mechanism as formed or shown. This relates to how the two interacting form-locking members FE and RW are partially formed or constructed. This refers to the Hirth tooth type tooth pair where mechanical clearance is not permitted.

[0062] The positioning of the rotor shaft RW can be achieved here through so-called speed regulation or so-called torque regulation, which has a so-called proportional part (P part) and a so-called integral part (I part).

[0063] The ideal orientation of the two locking members FE and RW relative to each other, or the rotational angular position of the rotor shaft RW corresponding to that ideal orientation—which itself is as described above—represents the support portion and is stored in the control unit SE. Inv Furthermore, it can be trained using learning or matching methods, thereby advantageously compensating for manufacturing tolerances between the two form-locking parts FE and RW.

[0064] The aforementioned control unit SE Inv SE A This includes a digital microprocessor unit (CPU), main memory (RAM), and storage media connected to a storage system and a bus system. The CPU is configured to process commands implemented as a program stored in the storage system, detect input signals from the data bus, and output output signals to the data bus. The storage system may have various storage media in the form of magnetic, solid, or other non-volatile media, on which corresponding computer programs for implementing the method and its advantageous designs are stored. The program can be implemented such that it embodies or executes aspects of the method described herein, so that the CPU can execute the steps of such a method and thus control the vehicle and parking locks or locking devices.

[0065] The following computer program is suitable for implementing the proposed method, having program code tools to implement all steps of each arbitrary claim in the claims or method claims when the program is executed in a CPU.

[0066] Computer programs can be easily read into existing drive and control electronics and used to control vehicles as well as locking actuators, parking locks, or locking devices.

[0067] For this purpose, a computer program product is provided, comprising program code tools stored on a computer-readable data carrier, so as to implement the method of each of the claims when the computer program product is executed in a CPU. The computer program product may also be integrated into driving electronics as an upgrade option.

[0068] While exemplary embodiments have been illustrated in the preceding description, it is hereby noted that numerous modifications are still possible. Furthermore, it is specifically stated that the exemplary embodiments are merely examples and should not limit the scope, application, or structure of protection. Rather, the preceding description provides guidance for those skilled in the art in implementing at least one exemplary embodiment, wherein a wide variety of changes can be made, particularly regarding the function and arrangement of the said components, without departing from the scope of protection as derived from the claims and the equivalent combination of features.

Claims

1. A method for positioning—particularly for positioning—the rotor shaft (RW) of an electric motor used to drive a vehicle, the method comprising the following steps: - The initial position of the rotor shaft (RW) is determined by multiple definable rotational angular positions, in which the rotor shaft (RW) can be locked or unlocked in a non-constrained manner by means of the form-locking element (FE) of the locking actuator (SA). in, To determine this initial position, the rotor shaft (RW) is divided into individual arc segments on its circumference such that each of these arc segments is assigned a form-locking segment that can engage with a complementary form-locking segment of the locking actuator (SA). - Position the rotor shaft (RW) to one of these rotational angular positions, wherein the absolute rotational angular position of the rotor shaft (RW) is detected by means of a rotor (shaft) position sensor. - Locking or unlocking the rotor shaft (RW) at this rotation angle position by causing the form-locking element (FE) to move into or out of the rotor shaft (RW) during the stroke.

2. The method according to claim 1, characterized in that, The following rotation angle position is adopted, in which the two locking parts have no relative angle with each other.

3. The method according to claim 1 or 2, characterized in that, Uniform indexing is used to divide the circumference of the rotor shaft (RW).

4. The method according to any one of the preceding claims, characterized in that, The form-locking element (FE) moves along the rotor shaft toward the rotor shaft (RW) during the axial travel motion.

5. The method according to any one of claims 1 to 4, characterized in that, After the form-locking member (FE) is moved into the rotor shaft (RW) in a free-restraint manner, the rotor shaft (RW) is stopped clockwise or counterclockwise relative to the form-locking member (FE) in order to tension the rotor shaft (RW) relative to the form-locking member (FE).

6. The method according to any one of claims 1 to 4, characterized in that, The rotor shaft (RW), which is stopped and tensioned relative to the form-locking member (FE) by the load, is positioned at a rotation angle position in which the rotor shaft is locked in a non-constrained manner beforehand so as to relax the rotor shaft (RW), and then the form-locking member (FE) is removed from the rotor shaft (RW) in a non-constrained manner.

7. A computer program for implementing the method according to any one of claims 1 to 6.

8. A computer program product comprising a program code tool stored on a computer-readable data carrier for implementing the method according to any one of claims 1 to 6 when the program code tool is executed on a computer.

9. A system comprising a locking actuator (SA) and a control unit (SE) for driving the locking actuator (SA). Inv SE SA ),in, Control Unit (SE) Inv SE SA The computer program product according to claim 8.

10. A vehicle having the computer program product according to claim 9.

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