Axle for two-track vehicle

Abstract

The invention relates to an axle of a two-track vehicle, comprising an axle differential (1) which can be connected on the input side to a main drive unit (EM1) and on the output side to the wheels (FR) of the axle by means of output shafts (4, 5) arranged on both sides, the axle having an electric motor (EM2) and a superimposed transmission (7) for an electric torque vectoring control, and the drive shafts (4, 5) being arranged on both sides of the drive shafts (4, 5) of the drive shafts (4, 5) of the drive shafts (4, 5) of the drive shafts (4, 5) of the drive shafts (4, 5) of the drive shafts (4, 5). The electric machine (EM2) can be actuated by means of a control unit (39) in order to vary the drive torque distributed to the wheels (FR). According to the invention, an evaluation module (41) is assigned to the control unit (39), which evaluation module carries out a torsion gap measurement of the superimposed transmission gear set (PG1, PG2) in order to determine an aging of the superimposed transmission gear set (PG1, PG2).

Description

Technical Field

[0001] The present invention relates to an axle for a dual-track vehicle as described in the preamble of claim 1, and a method for determining the aging of a superimposed transmission gear set in such an axle as described in claim 9. Background Technology

[0002] This type of axle incorporates an axle differential, which can be connected to the main drive unit (e.g., a motor) on the input side and to the wheels on the output side via driven shafts arranged on both sides. This type of axle also features electric torque vectoring, which includes a secondary drive unit (motor) and a superimposed transmission mechanism. The motor is driven by a control unit with a rotational torque. The torque distributed to the wheels can be adjusted according to the magnitude and / or direction of the rotational torque.

[0003] Superimposed transmission gear sets must provide very high gear ratios, such as 50:1. This high gear ratio is achieved through a series of speed-changing stages and planetary gear sets within the superimposed transmission mechanism, which are subject to manufacturing tolerances, resulting in significant torsional backlash in the superimposed transmission gear set. This torsional backlash must be controlled by the motor during quadrant changes during operation. Furthermore, the torsional backlash changes as the wear or aging of the superimposed transmission gear set intensifies. This alters the duration of quadrant changes, and more precisely, changes its smoothness. In the prior art, the aging of the superimposed transmission gear set is managed through monitoring the motor's rotational torque.

[0004] A drive unit for a motor vehicle is known from patent document DE 10 2021 126 647 B3, wherein a vibration state parameter is determined by means of a vibration compensation module based on the rotational speed of at least one component of a superimposed transmission mechanism, a vibration compensation control parameter is determined based on the vibration state parameter, and the drive control signal of the motor is adjusted by means of the vibration compensation control parameter.

[0005] A transmission system for a motor vehicle is known from patent document DE 10 2010 021 721 A1, wherein the torsional clearance present in the transmission mechanism before starting and when the starting gear is engaged is compensated by applying a small compensating torque set at the friction clutch to the input shaft of the transmission mechanism.

[0006] A method is known from patent document DE 10 2012 011 756 A1, which controls torsional clearance in a vehicle drivetrain during load changes by selectively adjusting the transition from coasting to traction. Here, the rotational torque or speed of the drive unit is adjusted such that the speed difference with a reference speed at the docking point is kept small to avoid impact docking. The torsional clearance, known from the components or determined during operation, is used for precise control to ensure smooth transmission of rotational torque. Summary of the Invention

[0007] The purpose of this invention is to provide an axle for a dual-track vehicle and a method thereof, which, compared with the prior art, allows for a simple determination of the aging of the superimposed transmission gear set in the axle.

[0008] This objective is achieved by the features of claim 1 or 9. Preferred improvements of the invention are disclosed in the dependent claims.

[0009] This invention relates to an axle for a two-wheeled vehicle, having an axle differential that can be connected to a main drive unit on the input side and to the wheels of the axle on the output side via driven shafts or output shafts arranged on both sides. For electric torque vector control / for the electric torque vector control unit, the axle has a motor and a superimposed transmission mechanism. The motor is driven by a control unit to change the drive torque distributed to the wheels. According to the characteristic portion of claim 1, the aging determination of the superimposed transmission mechanism gear set is performed by providing a diagnostic module to the control unit, which performs a torsional clearance measurement on the superimposed transmission mechanism gear set to determine the aging of the superimposed transmission mechanism gear set. Through the torsional clearance measurement, the diagnostic module can infer the degree of aging or wear of the superimposed transmission mechanism gear set.

[0010] Therefore, according to the present invention, the motor determines how much its shaft must rotate to apply a predetermined limiting torque. The motor performs this operation in both directions of rotation. If wear occurs in the gear set, the travel gradually widens in multiple wear measurements. By comparing these values ​​with nominal / rated values, the motor can compensate for gear set aging. Furthermore, it can compensate for the idle travel that the motor must undertake during equipment switching.

[0011] It is important to emphasize here that, during operation, steering performance directly depends on how well the motor can compensate for the gear set's idle travel. The better the gear set's idle travel is compensated, the better the steering performance, because at this point, inertial torque can be directly compensated without interruption.

[0012] Therefore, this invention is based on the fact that gear set aging leads to increased torsional clearance. The object of this invention is to determine the torsional clearance, identify changes in torsional clearance, and store this information in historical data. Subsequently, it can be determined whether the gear set is aged and to what extent. Based on this, aging compensation can be performed on the lost torque of the gear set.

[0013] In a variant of the implementation, when performing torsional clearance measurement, if the motor exceeds the applicable wheel differential torque, the motor applies an applicable positive wheel differential torque (e.g., 10 Nm wheel differential torque) to the gear set and stores the rotor shaft torsional angle. Alternatively, when performing torsional clearance measurement, if the motor exceeds the applicable wheel differential torque, the motor applies an applicable negative wheel differential torque to the gear set and stores the rotor shaft torsional angle.

[0014] When performing torsional clearance measurement, the motor can apply both the maximum positive applicable wheel differential torque (e.g., 20 Nm wheel differential torque) and the maximum negative applicable wheel differential torque to the gear set. Here, the motor can limit the wheel differential torque used for torsional clearance measurement (hereinafter often referred to as diagnostic torque) to an applicable variation gradient (e.g., 50 Nm / s).

[0015] Based on the determined torsional angles of the two gear sets, the motor can calculate the absolute torsional clearance (hereinafter also referred to as the actual torsional clearance) and store it as a historical storage value and a measured value block. Additionally, the variation in the actual torsional clearance can be calculated based on the determined torsional angles of the two gear sets and stored as a historical storage value and a measured value block.

[0016] The diagnostic module can also generate a histogram based on the actual torsional clearance, plotting the actual torsional clearance in the histogram according to vehicle usage time / cumulative vehicle usage time / cumulative vehicle running time, and storing it as historical stored values ​​and measurement value blocks / measurement value data blocks. Alternatively and / or additionally, a histogram can be generated based on the actual torsional clearance, plotting the actual torsional clearance in the histogram according to vehicle mileage, and storing it as historical stored values ​​and measurement value blocks.

[0017] In addition, the diagnostic module can generate a histogram based on the actual torsional clearance, plotting the change in actual torsional clearance over time with vehicle usage, and storing it as historical values ​​and measurement value blocks. Alternatively and / or additionally, a histogram can be generated based on the actual torsional clearance, plotting the change in actual torsional clearance over time with vehicle mileage, and storing it as historical values ​​and measurement value blocks.

[0018] The application switch allows users to select whether to use and which torsional clearance measurement value (absolute value, absolute value variation, histogram average, histogram variation average) as the basis for determining gear set torque loss. Torsional clearance measurement can be initiated, for example, in the workshop / factory via a diagnostic program. Torsional clearance determined over time can be returned to the diagnostic program. If the torsional clearance measurement value is used for gear set aging determination, the possible maximum value determined by the torsional clearance measurement must be limited.

[0019] In a specific implementation, when measuring torsional clearance, the actual torsional clearance is compared with the nominal value stored in the diagnostic module. Based on this comparison, the control unit performs aging compensation for the gear set loss torque present in the superimposed transmission mechanism, which is taken into account when driving the motor.

[0020] Torsional clearance measurement can be performed, for example, in a diagnostic procedure conducted in the workshop, where the wheels are locked. In a preferred process variant, the actual torsional clearance can be detected by the following process steps: In a first process step, the control unit drives the motor with a predetermined diagnostic torque, which depends on the current supplied to the motor. This current is increased until the diagnostic torque is reached. Upon reaching the diagnostic torque, a rotation angle sensor detects a first torsional angle corresponding to the diagnostic torque. In a second process step, the control unit drives the motor with the diagnostic torque in the opposite rotation direction. Upon reaching the diagnostic torque, the rotation angle sensor detects the corresponding torsional angle. The diagnostic module calculates the actual torsional clearance based on the sum of the values ​​of the first and second torsional angles.

[0021] To further enhance the persuasiveness of aging determinations, at least one histogram can be generated in the diagnostic module, plotting multiple actual torsional clearances in chronological order over vehicle usage time or mileage. The histogram can be read in the workshop using the diagnostic module. For example, the histogram may plot the following:

[0022] - The absolute value of the actual torsional clearance over vehicle usage time;

[0023] - The absolute value of actual torsional clearance as a function of vehicle mileage;

[0024] - The actual torsional clearance varies with vehicle usage time; and / or

[0025] - Actual torsional clearance varies with vehicle mileage. Attached Figure Description

[0026] Embodiments of the present invention will now be described with reference to the accompanying drawings. Wherein,

[0027] Figure 1 and Figure 2The structure and working principle of the axle according to the present invention are shown. Detailed Implementation

[0028] exist Figure 1 The diagram illustrates the transmission structure of, for example, an electric rear axle of a dual-track vehicle. The axle has a motor serving as the main drive EM1, which is drive-connected to the input side of the axle differential 1. Driven shafts 4 and 5 guide from the output side of each axle differential to one of the axle wheels FR. Figure 1 In the middle, the axle differential 1 is a bevel gear differential, which has a differential housing 3 on the drive side, in which there are compensating bevel gears and axle bevel gears, which are respectively arranged on one of the driven shafts 4 and 5 in a manner that prevents relative rotation.

[0029] The axle can perform electric torque vectoring control. For this purpose, the axle has a superimposed transmission mechanism 7 and a motor as an auxiliary drive EM2. Figure 1 In this configuration, the superimposed transmission mechanism 7 includes two planetary transmission mechanisms PG1 and PG2 arranged side-by-side along the axial direction and coupled to each other, coaxial with the driven shafts 4 and 5. In the two planetary transmission mechanisms, the input-side planetary transmission mechanism PG1 is connected to the rotor shaft 11 of the motor EM2 via a front gear stage 9. The input-side planetary transmission mechanism PG1 has a sun gear 13, which is connected to the radial external gear ring 15 via planetary wheels. The planetary wheels are rotatably supported on a rotating planetary gear carrier 17. Similarly, the output-side planetary transmission mechanism PG2 has a sun gear 19, which is connected to the radial external gear ring 21 via planetary wheels. The planetary wheels are rotatably supported on a rotating planetary gear carrier 23. The gear rings 15 and 21 of the two planetary transmission mechanisms PG1 and PG2 are connected to the same gear ring shaft 25.

[0030] In the input-side planetary transmission mechanism PG1, the sun gear 19 forms the input element, which, together with the front gear 27, is non-rotatably arranged on the transmission input shaft 29. On the other hand, the planet carrier 17 of the input-side planetary transmission mechanism 1 forms the output element, which is non-rotatably connected to the driven shaft 5 on the transmission side via a drive flange 31. In the output-side planetary transmission mechanism PG2, the planet carrier 23 forms the output element, which is connected to the transmission output shaft 35 via a coupling flange 33. This transmission output shaft is also non-rotatably connected to the differential housing 3 of the axle differential 1. Furthermore, the sun gear 25 of the second planetary transmission mechanism PG2 is fixedly connected to the transmission housing 37 relative to the housing.

[0031] If from Figure 1It is understood that the electronic control unit 39 can drive the motor EM2 with rotational torque. If the motor EM2 is deactivated during driving, only the main drive unit EM1 introduces rotational torque into the two wheels FR through the axle differential 1 in a 50 / 50 distribution. Depending on the driving conditions, the control unit 39 can control the rotational torque of the motor EM2. Based on the magnitude and / or direction of rotation of the rotational torque, the torque distributed to the two wheels FR can be changed as needed, starting from a 50 / 50 distribution.

[0032] If from Figure 1 It is understood that a diagnostic module 41 is provided for the control unit 39, which can be used to determine the aging of the superimposed transmission mechanism gear sets PG1 and PG2 by means of torsional clearance measurement. During torsional clearance measurement, the actual torsional clearance v is compared in the diagnostic module 41. ist The nominal value v0 is compared with that stored in the diagnostic module 41. Based on the comparison, a difference ∆v is obtained, and the control unit 39 performs aging compensation for the gear set loss torque present in the superimposed transmission mechanism 7 based on this difference. Furthermore, for example, in a diagnostic program that can be performed in a workshop, the actual torsional clearance v can be considered. ist The degree of wear of the gear set in the superimposed transmission mechanism is determined by comparing it with the nominal value v0.

[0033] Below, in conjunction with Figure 2 The diagram shown illustrates the methods used to determine the actual torsional clearance v. ist The process steps are as follows: First, when preparing for torsional clearance measurement, lock the wheel FR. Next, in the first process step, control unit 39 operates at a predetermined diagnostic torque M. D The drive motor EM2 is controlled by the current supplied to it. This current is increased until the diagnostic torque MD is reached. Once the diagnostic torque MD is reached... D At that time, the rotation angle sensor 43 of motor EM2 detects the corresponding motor shaft rotation angle α1. In the second process step, the control unit 39 rotates in the opposite direction and with the diagnostic torque M D Drive motor EM2. When the diagnostic torque M is reached... D At that time, the rotation angle sensor 43 detects the corresponding second rotor shaft torsion angle α2. The diagnostic module 41 calculates the actual torsional clearance v based on the sum of the values ​​of the first rotor shaft torsion angle α1 and the second rotor shaft torsion angle α2. ist .

[0034] List of reference numerals

[0035] 1. Axle differential

[0036] 3. Differential housing

[0037] 4, 5 Driven Shaft

[0038] 7. Superimposed transmission mechanism

[0039] 9. Sub-shaft

[0040] 11 Rotor shaft

[0041] 13. Sun Chakra

[0042] 15 Gear Ring

[0043] 17 Planetary Gear Carrier

[0044] 19. Sun Wheel

[0045] 21 Gear Ring

[0046] 23 Planetary Gear Carrier

[0047] 25 Gear Shaft

[0048] 27. Front gear

[0049] 29. Input shaft of transmission mechanism

[0050] 31 Driven flange

[0051] 33 Coupled Flange

[0052] 35. Output shaft of transmission mechanism

[0053] 37 Transmission mechanism housing

[0054] 39 Control Unit

[0055] 41 Diagnostic Module

[0056] 43 Rotation Angle Sensor

[0057] FR wheels

[0058] EM1 Main Drive Unit

[0059] EM2 motor

[0060] PG1 Planetary Transmission Mechanism

[0061] PG2 Planetary Transmission Mechanism

[0062] v ist Actual torsional clearance

[0063] v0 nominal value

[0064] α1, α2 Rotor shaft torsional angles

[0065] Δv Tooth flank clearance difference

[0066] M D Diagnostic torque

Claims

1. An axle for a dual-track vehicle, the axle having an axle differential (1) connectable to a main drive unit (EM1) on the input side and connectable to the wheels (FR) of the axle on the output side via driven shafts (4, 5) arranged on both sides, wherein, For electric torque vector control, the axle has a motor (EM2) and a superimposed transmission mechanism (7), wherein the motor (EM2) can be driven by a control unit (39) to change the drive torque distributed to the wheels (FR). Its features are, An evaluation module (41) is provided for the control unit (39), which performs torsional clearance measurement on the superimposed transmission gear set (PG1, PG2) to determine the aging of the superimposed transmission gear set (PG1, PG2).

2. The axle according to claim 1, characterized in that, When measuring the torsional clearance in the evaluation module (41), the actual torsional clearance (v) can be measured. ist The value (v0) is compared with the nominal value (v0) stored in the evaluation module (41).

3. The axle according to claim 2, characterized in that, Based on the actual torsional clearance (v) ist The control unit (39) performs aging compensation for the gear set loss torque present in the superimposed transmission mechanism (7) by comparing the nominal value (v0) with the nominal value (v0).

4. The axle according to any one of the preceding claims, characterized in that, The torsional clearance measurement is performed, for example, in a diagnostic procedure that can be executed in a workshop, in which the wheel (FR) is locked.

5. The axle according to claim 4, characterized in that, The actual torsional clearance (v) ist The following process steps can be used to determine the process, where: In the first process step, the control unit (39) operates at a predetermined diagnostic torque (M). D The motor (EM2) is driven and controlled to achieve the diagnostic torque (M). D When the rotation angle sensor (43) detects the first rotor shaft torsion angle (α1) corresponding to the diagnostic torque, and In the second process step, the control unit (39) rotates in the opposite direction and with the diagnostic torque (M) D The motor (EM2) is driven and controlled to achieve the diagnostic torque (M). D When the rotation angle sensor (43) detects the second rotor shaft torsion angle (α2) corresponding to the diagnostic torque, the rotation angle sensor (43) detects the second rotor shaft torsion angle (α2).

6. The axle according to claim 5, characterized in that, The evaluation module (41) calculates the actual torsional clearance (v) by summing the values ​​of the torsional angles (α1) of the first rotor shaft and the second rotor shaft (α2). ist ).

7. The axle according to any one of the preceding claims, characterized in that, The evaluation module (41) can generate at least one histogram that plots multiple actual torsional clearances (v) in chronological order over the vehicle's usage time or cumulative mileage. ist 1. v ist 2, ...), and the histogram can be read in the workshop using a diagnostic module.

8. The axle according to claim 7, characterized in that, The following was plotted in the histogram: - The actual torsional clearance (v) during the vehicle's service life ist 1. v ist 2. The absolute value of ... - The actual torsional clearance (v) within the vehicle's cumulative mileage. ist 1. v ist 2. The absolute value of ... - The variation in the actual torsional clearance during the vehicle's service life; and / or - The change in the actual torsional clearance within the vehicle's mileage.

9. A method for determining the aging of a superimposed transmission gear set (PG1, PG2) in an axle according to any one of the preceding claims.

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