Vehicle and method for releasing parking lock in such vehicle

Abstract

The invention relates to a vehicle having an electric motor (EM) which drives a wheel (2) via a transmission mechanism, in which a parking lock (4) having a pawl (5) and a locking gear (7) is mounted, in a specific parking state, the engaged pawl (5) is clamped, and in which the engaged pawl (5) is unclamped for unstressed parking lock release. A central control unit (11) actuates a pulse inverter (PWR) of an electric machine (EM) in order to rotate a rotor shaft (1) of the electric machine by a target rotation angle (alphasoll) in a direction of rotation (D), in particular to generate a reduced-pressure torque (M), by means of which clamping acting on the parking lock (4) can be reduced. According to the invention, the pulse inverter (PWR) is connected together with the rotor position sensor (15) into the adjustment circuit (R). By means of the adjustment circuit (R), a rotational angle adjustment mode can be carried out, in which the electric machine (EM) is actuated by means of the reduced-pressure torque (M).

Description

Technical Field

[0001] The present invention relates to a vehicle having a parking lock mechanism as described in the preamble of claim 1, and a method for disengaging the parking lock mechanism as described in claim 10. Background Technology

[0002] Battery-powered vehicles have an electric motor that drives the wheels via a transmission mechanism. A parking lock mechanism is installed within the transmission mechanism, consisting of a locking pawl and a locking gear that interacts with the pawl. When the parking lock mechanism is engaged, the pawl and locking gear engage in a form-fitting manner, thereby preventing the wheels from rotating. The torque applied to the parking lock mechanism by the locked wheels is transmitted to the drive module housing via the form-fitting connection between the locking gear and the pawl, and further to the vehicle body or subframe via the assembly bracket. In certain parking situations, such as when parking on a slope, jamming occurs in the parking lock mechanism. Therefore, to pull the pawl out of the locking gear, a correspondingly powerful and therefore expensive parking lock mechanism actuator is required, capable of overcoming the frictional forces between the pawl and the locking gear.

[0003] Alternatively, in this type of vehicle, the locking gear is rotated relative to the locking pawl, allowing the pawl to disengage with almost no force. This results in a comfort advantage because no vibration occurs in the transmission mechanism when the pawl disengages.

[0004] A method for operating a parking lock mechanism for a motor vehicle is known from DE 10 2017 121 007 A1. This parking lock mechanism has a locking pawl and a locking gear that works in conjunction with the locking pawl. In the event of jamming between the locking pawl and the locking gear due to lane incline, a control device is used to selectively rotate the locking gear to eliminate the jamming during the disengagement process of the parking lock mechanism.

[0005] A parking lock mechanism is known from DE 10 2017 123076 A1. In order to disengage the parking lock mechanism under low load, a detection device for identifying the position of the locking element of the parking lock mechanism and a control device for rotating the parking lock mechanism stop wheel based on the position of the locking element are provided.

[0006] A method for disengaging a parking lock mechanism is known from DE 10 2014 207 997 A1, wherein a decompression torque is applied to the parking lock mechanism to disengage it. This decompression torque is applied to the parking lock mechanism via a corresponding control.

[0007] Existing technologies only generally disclose rotating the locking gear to disengage the parking lock mechanism and eliminate jamming, thus preventing the parking lock mechanism from disengaging due to stress. Therefore, existing technologies lack specific technical solutions regarding how to precisely rotate the locking gear to depressurize the engaged parking lock mechanism so that it can smoothly disengage. Summary of the Invention

[0008] The purpose of this invention is to provide an electric vehicle with a parking lock mechanism, wherein jamming in the parking lock mechanism can be eliminated in a simple and targeted manner to ensure a smooth disengagement process of the parking lock mechanism.

[0009] This objective is achieved by the features described in claim 1 or 10. Preferred improvements of the invention are disclosed in the dependent claims.

[0010] This invention is based on a vehicle with an electric motor that drives the wheels via a transmission mechanism. A parking lock mechanism with a pawl / ratchet / stop pawl / brake pawl and a locking gear acting in conjunction with the pawl is installed in the transmission mechanism. In a specific parking state, such as when parking on a slope, the engaged pawls become jammed. To ensure a stress-free disengagement process, the central controller operates the motor's pulse inverter to rotate the motor's rotor shaft by a target rotation angle in the direction of rotation. This generates a pressure-reducing torque, which reduces the jamming effect on the parking lock mechanism. According to the invention, to provide a precise pressure reduction function and thereby perform a stress-free parking lock mechanism disengagement process, the motor's pulse inverter, along with a rotor position sensor, a comparator module, and an adjustment module, is connected to an adjustment circuit. Given the pressure reduction of the parking lock mechanism, a rotation angle adjustment mode is executed using the adjustment circuit. In this mode, the comparator module generates torque adjustment parameters by comparing the target rotation angle with the actual rotation angle of the rotor shaft detected by the rotor position sensor. The adjustment module controls the motor with reduced torque based on this torque adjustment parameter. The adjustment circuit enables a precise, targeted process with correspondingly high adjustment quality, so as to initiate the parking lock disengagement process without load.

[0011] In one technical solution, the pressure reduction torque can be gradually increased within an adjustment range from 0 to the maximum value using an adjustment module. Therefore, the following adjustment process is performed in the adjustment circuit: if there is a rotation angle difference between the target rotation angle and the actual rotation angle, the adjustment module increases the pressure reduction torque towards the maximum value, more precisely, until the actual rotation angle matches the target rotation angle in the comparator module. Alternatively, the adjustment module increases the pressure reduction torque until the pressure reduction torque reaches its maximum value.

[0012] Once the actual rotation angle detected by the rotor position sensor in the comparator module matches the target rotation angle, the pulse inverter generates a torque-free signal. In the presence of this torque-free signal, the central controller operates the parking lock mechanism actuator to initiate the parking lock mechanism disengagement process without load.

[0013] The above-described process sequence is performed in the fault-free rotation angle adjustment mode. In contrast, the following describes aspects of the invention in a faulty rotation angle adjustment mode: that is, during the initial adjustment in a faulty rotation angle adjustment mode, the adjustment module can increase the pressure reduction torque up to its maximum value, more precisely, even if the target rotation angle does not match the actual rotation angle. In this process, the pulse inverter identifies a fault condition. This fault condition occurs, for example, when the rotor shaft rotates in the wrong direction or when the rotor position sensor malfunctions.

[0014] When this fault condition occurs, the following process chain can be executed in the vehicle, accordingly.

[0015] - Once the reduced-pressure torque is increased to its maximum value using the regulating module, the pulse inverter generates a torque-free signal; and

[0016] – In the absence of a torque signal, the central controller operates the parking lock mechanism actuator to perform the parking lock mechanism disengagement process.

[0017] If the disengagement process fails, a secondary adjustment process will be performed in the opposite direction of rotation during the subsequent process. If the target rotation angle is not achieved in the secondary adjustment process either, the pulse inverter will generate an alarm message for the driver.

[0018] The following describes the signal processing in the vehicle's parking management system, which is executed when an unsuccessful disengagement occurs after the initial adjustment process: During an unsuccessful disengagement after the initial adjustment, the parking lock mechanism actuator generates a fault signal. Based on this, a secondary adjustment process is initiated.

[0019] In the first embodiment, the fault signal from the parking lock mechanism actuator is first transmitted to the central controller, which then accordingly controls the pulse inverter to initiate a secondary adjustment process. Alternatively, for simplified signal processing, a second embodiment is provided whereby the parking lock mechanism actuator can be directly signal-connected to the pulse inverter, i.e., without an intermediate connection to the central controller. In this case, the fault signal generated by the parking lock mechanism actuator is transmitted directly to the pulse inverter, bypassing the central controller.

[0020] In a specific implementation, the engagement of the parking lock mechanism is identified by the central controller as follows: the central controller can be connected to a vehicle attitude sensor signal. This vehicle attitude sensor detects the vehicle attitude angle. Based on the detected vehicle attitude angle, the central controller can determine whether there is engagement in the parking lock mechanism. Furthermore, the central controller also determines the target rotation direction based on the detected vehicle attitude angle.

[0021] In addition, the target rotation angle can be stored as a fixed parameter in the pulse inverter or central controller. Attached Figure Description

[0022] An embodiment of the present invention will now be described with reference to the accompanying drawings.

[0023] Figure 1 An exemplary block diagram is shown, illustrating the structure and operation of the parking management system according to the present invention. Detailed Implementation

[0024] Figure 1 The diagram roughly schematically illustrates an electric axle for a dual-track vehicle. The axle has a motor EM that drives both wheels of the axle via a transmission mechanism. For this purpose, the motor EM is driven by a differential via an intermediate / secondary shaft 1, with an output shaft 3 from its output side leading to the corresponding wheel 2. A wheel brake is assigned to each of the two wheels 2.

[0025] exist Figure 1 In the diagram, the vehicle's parking management system PM consists of a parking actuator 6 that acts on the brake of the right wheel and a parking locking mechanism 4. The parking locking mechanism consists of a locking pawl 5 supported on the side of the vehicle body and a locking gear 7 that works together with the locking pawl. The locking gear is connected to the output shaft 3 in a non-rotatable manner.

[0026] The locking claw 5 can be engaged or disengaged by the parking lock mechanism actuator 9. The parking lock mechanism actuator 9 can be controlled by the central controller 11. The central controller 11 controls the parking lock mechanism actuator 9 to engage or disengage the parking lock mechanism 4. In the accompanying drawings, the central controller 11 is signal-connected to the vehicle attitude sensor 13, which detects the vehicle attitude angle of the parked vehicle. Furthermore, the central controller 11 is signal-connected to the pulse inverter PWR of the motor EM.

[0027] When parked, the parking lock mechanism 4 is engaged to prevent the parked vehicle from rolling / slipping. Once the central controller 1 detects the driver's intention to disengage, it first assesses, based on the vehicle attitude angle detected by the vehicle attitude sensor 13, whether the engaged parking lock mechanism is jammed, such as when parking on a slope. If the central controller 11 detects this jamming of the engaged parking lock mechanism 9, it operates the pulse inverter PWR of the motor EM in a target rotation direction D, which has been determined in the central controller 11 based on the vehicle attitude. In this way, the rotor shaft 1 rotates along the rotation direction D by a target rotation angle α. soll The rotor rotates, and the target rotation angle is stored as a fixed parameter in the pulse inverter PWR. The rotor rotates simultaneously with the generation of the decompression torque M, which reduces the clamping force acting on the parking lock mechanism 4.

[0028] The core of this invention lies in the technical solution described below, namely, precise control of the rotor shaft 1 of the motor EM to ensure a smooth (i.e., torque-free) disengagement process of the parking lock mechanism: The pulse inverter PWR has a comparator module 17 and an adjustment module 19, which, together with the rotor position sensor 15, are connected to / integrated into the adjustment circuit R. With the help of the adjustment circuit R, a rotation angle control mode can be executed, in which the comparator module 17 is controlled by the target rotation angle α. soll The actual rotation angle α of rotor shaft 1 detected by rotor position sensor 15 ist The torque adjustment parameter y is generated by comparing the two.

[0029] Based on the torque adjustment parameter y generated by comparator module 17, downstream regulation module 19 of pulse inverter PWR controls motor EM with reduced torque M. As shown in the attached figure, regulation module 19 can operate from 0 to the maximum value M. max The pressure relief torque M is gradually increased within the adjustment range.

[0030] The adjustment process can be performed using the adjustment loop R as follows: at the target rotation angle α soll Compared with the actual rotation angle α ist When a rotation angle difference exists, comparator module 17 generates a torque adjustment parameter y, which is related to the magnitude of the rotation angle difference. The torque adjustment parameter y controls adjustment module 19, which uses reduced torque to control motor EM. Adjustment module 19 directs the reduced torque M towards its maximum value M. max The direction increases until the actual rotation angle α in comparator module 17 is reached. ist Rotation angle α with respect to the target soll Consistent.

[0031] Once the actual rotation angle α is detected by the rotor position sensor 15 in the comparator module 17... ist Rotation angle α with respect to the target soll If they are consistent, the pulse inverter PWR will generate a torque-free signal S. M When such a torque-free signal S exists... M At this time, the central controller 11 controls the parking lock mechanism actuator 9 to start the parking lock mechanism disengagement process.

[0032] The above description outlines the adjustment process in a fault-free rotation angle adjustment mode. In contrast, the following describes a faulty rotation angle adjustment mode, which exemplarily occurs when the central controller 1 determines an incorrect target rotation direction D or when the rotor position sensor 15 malfunctions.

[0033] In this fault condition, during the initial adjustment process using the rotation angle adjustment method, the adjustment module 19 can increase the pressure reduction torque M up to its maximum value M. max， More precisely, before the target rotation angle α is reached... soll Compared with the actual rotation angle α ist Under the condition of consistency, the parking management system (PM) can execute the following process chain, accordingly.

[0034] - Once the pressure relief torque M has been increased by the regulating module 19 until the maximum value M is reached. max Then the pulse inverter PWR generates a torque-free signal S. M ;as well as

[0035] – In the presence of no torque signal S M In this case, the central controller 11 operates the parking lock mechanism actuator 4 to initiate the disengagement process.

[0036] If the disengagement process fails, the parking lock mechanism actuator 9 generates a fault signal S. F The fault signal is transmitted to the central controller 11. In response, the central controller 11 manipulates the pulse inverter PWR to initiate a secondary adjustment process with the opposite rotation direction. If the target rotation angle α is not reached during the secondary adjustment process... soll Compared with the actual rotation angle α ist If the pulse inverter PWR is consistent with the signal, it will generate an alarm message for the driver.

[0037] In the above embodiment, in the event of a malfunction, during the initial adjustment process performed by adjusting the rotation angle, the adjustment module 19 can increase the pressure relief torque M until it reaches its maximum value M. max， More precisely, before the target rotation angle α is reached... sollCompared with the actual rotation angle α ist Under the condition of consistency, the alternative adjustment module 19 can also automatically reverse the rotation direction and attempt to achieve the desired target rotation angle in the opposite direction to the target rotation direction. This alternative architecture saves transmission time on the communication bus.

[0038] List of reference numerals in the attached diagram:

[0039] 1. Rotor shaft

[0040] 2 wheels

[0041] 3 Output shaft

[0042] 4 Parking Lock Mechanism

[0043] 5 locking claws

[0044] 6 Parking actuator

[0045] 7 Locking Gear

[0046] 9. Parking lock mechanism actuator

[0047] 11 Central Controller

[0048] 13 Vehicle attitude sensor

[0049] 15 Rotor position sensor

[0050] 17 Comparator Module

[0051] 19 Adjustment Module

[0052] R Adjustment Circuit

[0053] α soll Target rotation angle

[0054] α ist Actual rotation angle

[0055] S F Fault signals

[0056] PWR pulse inverter

[0057] S M No torque signal

[0058] M pressure relief torque

[0059] y Torque adjustment parameters

[0060] PM Parking Management

Claims

1. A vehicle having an electric motor (EM) that drives wheels (2) via a transmission mechanism, wherein, A parking locking mechanism (4) with locking claws (5) and locking gears (7) is installed in the transmission mechanism, wherein the locking claws (5) engage and lock in a specific parking state, and wherein, in order to disengage the parking locking mechanism without stress, the central controller (11) controls the pulse inverter (PWR) of the motor (EM) to rotate the rotor shaft (1) of the motor by a target rotation angle (α) in the direction of rotation (D). soll More precisely, when a pressure-reducing torque (M) is generated, this pressure-reducing torque can be used to reduce the clamping force acting on the parking lock mechanism (4). Its features are, The pulse inverter (PWR)'s regulation module (19) and comparator module (17), together with the rotor position sensor (15), are connected to the adjustment circuit (R). The adjustment circuit (R) enables a rotation angle adjustment mode, in which the comparator module (17) adjusts the target rotation angle (α). soll The actual rotation angle (α) detected by the rotor position sensor (15) and the rotor position sensor (15) ist The torque adjustment parameter (y) is generated by comparing the values ​​of the two components. Based on this torque adjustment parameter, the adjustment module (19) of the pulse inverter (PWR) controls the motor (EM) with a reduced torque (M).

2. The vehicle according to claim 1, characterized in that, With the help of the adjustment module (19), from 0 to the maximum value (M) max Within the adjustment range, the pressure reduction torque (M) can be gradually increased, and / or, during the adjustment process, at the target rotation angle (α) soll ) and the actual rotation angle (α) ist If there is a difference between the two values, the adjustment module (19) will adjust the pressure reduction torque (M) towards the maximum value (M). max The direction of rotation increases until the actual rotation angle (α) in the comparator module (17) increases. ist ) and target rotation angle (α) soll The pressure relief torque (M) remains constant, or until it reaches its maximum value (M). max ).

3. The vehicle according to claim 1 or 2, characterized in that, If the actual rotation angle (α) detected by the rotor position sensor (15) in the comparator module (17) is... ist ) corresponds to the target rotation angle (α) ist Then the pulse inverter (PWR) generates a torque-free signal (S). M ); and in the presence of such a torque-free signal (S) M In the event of a parking lock mechanism, the central controller (11) manipulates the parking lock mechanism actuator (9) to initiate the parking lock mechanism disengagement process.

4. The vehicle according to claim 2 or 3, characterized in that, If, during the initial adjustment, the adjustment module (19) increases the pressure reduction torque (M) until it reaches its maximum value (Mmax), then... max ) ， However, the target rotation angle (α) was not reached. soll ) and the actual rotation angle (α) ist If the rotor shaft (1) rotates in the wrong direction, or the rotor position sensor (15) fails, the pulse inverter (PWR) determines the fault condition.

5. The vehicle according to claim 4, characterized in that, When this fault condition occurs, the following process chain can be executed accordingly. - Once the pressure relief torque (M) is increased to its maximum value (M) using the adjustment module (19), max Then the pulse inverter (PWR) generates a torque-free signal (M). F );as well as - In the presence of no torque signal (S) M In the event of a parking lock mechanism, the central controller (11) manipulates the parking lock mechanism actuator (9) to disengage the parking lock mechanism.

6. The vehicle according to claim 5, characterized in that, If the parking lock mechanism fails to disengage after the initial adjustment, a second adjustment process is initiated in the opposite direction of rotation; if the target rotation angle (α) is not achieved during the second adjustment process either... soll ) and the actual rotation angle (α) ist If the signal is consistent with the signal, the pulse inverter (PWR) will generate an alarm message for the driver.

7. The vehicle according to claim 4, 5 or 6, characterized in that, If an unsuccessful disengagement of the parking lock mechanism occurs after the initial adjustment process, the parking lock mechanism actuator (9) generates a fault signal (S). F Based on this fault signal, a secondary adjustment process is initiated; in particular, the fault signal (S) F The fault signal (S) is transmitted from the parking lock mechanism actuator (9) to the central controller (11), which accordingly controls the pulse inverter (PWR); or the parking lock mechanism actuator (9) is directly connected to the pulse inverter (PWR), that is, without the central controller (11) in between, so that the fault signal (S) is transmitted from the parking lock mechanism actuator (9) to the central controller (11). F The signal is transmitted directly to the pulse inverter (PWR) across the central controller (11).

8. The vehicle according to any one of the preceding claims, characterized in that, The central controller (11) is connected to the vehicle attitude sensor (13) that detects the vehicle attitude angle; in particular, the central controller (11) determines, based on the detected vehicle attitude angle, whether there is a engaged parking lock mechanism (4) locking.

9. The vehicle according to any one of the preceding claims, characterized in that, Rotate the target by the angle (α) soll The parameters are stored as fixed parameters in the pulse inverter (PWR) or central controller (11).

10. A method for disengaging a parking lock mechanism (4) in a vehicle according to any one of the preceding claims.

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