DE102022210303B3 - Method for determining the wear of a claw clutch - Google Patents

Abstract

A method for determining the wear of an electromechanically actuated claw clutch, wherein the actuator of the claw clutch comprises an electric motor which can directly pivot a toothed shift fork (1) via a pinion, the shift fork (1) having an axial path when pivoted by the electric motor in the direction the axis of a sleeve (2), in order to take the sleeve (2) axially and to move it from a decoupled position (3) to a coupled position (4) of the claw clutch, and/or vice versa, during which During operation of the claw clutch, current angles (phiOfs, phiActTTC, phiActFullRng, phiBL) of the electric motor rotor that are characteristic of the wear of the claw clutch are determined.

Description

Field of invention

The present invention relates to a method for determining the wear of an electromechanically actuated dog clutch.

State of the art

Claw clutches, particularly installed in motor vehicles, are known per se and are used, for example, to couple or decouple a non-permanently driven axle from a driven shaft. It is also known to actuate a dog clutch using a BLDC motor, whereby a toothed shift fork of the dog clutch is pivoted directly via a pinion, i.e. a gear, which thereby covers a required axial path.

The translation between the pinion and the toothed shift fork can be designed in such a way that the entire axial travel, including wear reserve, can be covered within one revolution of the engine. A clear determination of the actuator position is then possible without the cost of an additional position sensor if the overall wear of the actuator system is known.

Since an actuator system experiences increasing wear over the course of its service life, the wear values determined initially when producing a motor vehicle with a built-in claw clutch match less and less with the mechanical reality as the service life increases. As a result, during the operation of such a motor vehicle, problems arise such as the tooth-to-tooth area (i.e. the tooth overlap area) is no longer recognized when coupling and as a result the switching process cannot be completed or can be completed inadequately, or that it cannot be completed when decoupling It is recognized early enough when the overlap area of the toothing has been left and the sleeve is braked too late, with the risk of suddenly hitting the stop.

If the total wear of the system is not known, it can also happen that the actuator requires more than one revolution for the total travel of the actuator, which could lead to an incorrect interpretation of the current system state.

From the DE 10 2019 220 179 B3 is a shift drum arrangement for a switching device of a transmission unit, in particular for motor vehicles, known, with a shift drum body which is rotatable about a shift drum axis, a first and at least a second shift contour being formed on the shift drum body, which extend over 360 degrees of the peripheral section of the shift drum body , wherein the first and second switching contours are formed in an axial and / or radial direction, wherein a first switching element engages in the first switching contour and a second switching element engages in the second switching contour in such a way that they are rotated by rotating the switching drum body by means of the corresponding switching contour axial direction of the shift drum body, wherein the first shift contour has an optional path, and wherein the first and second shift elements can be coupled via a switchable coupling device in such a way that an axial displacement of the second shift element on the first shift element for the purpose of shifting into a neutral gear position, that is assigned to the optional path can be effected.

The DE 10 2019 216 566 B3 discloses an actuating device for actuating a clutch-controlled transfer case with a two-stage intermediate transmission comprising an electric motor and at least one component which can be rotated directly or indirectly via the electric motor, namely referred to as a worm wheel, clutch bell and shift gate, with two links on the worm wheel, namely a first link and a second Link, are arranged, which are designed and arranged such that they each represent at least one pressable stop for a position-fixed spring-loaded element.

document WO 2022/157 143 A1 teaches a method for operating a claw clutch arrangement for a motor vehicle with a clutch body, the clutch body having first teeth in a first toothing, and an axially movable sliding sleeve arrangement with second teeth in a second toothing, the sliding sleeve arrangement having a switching ring and a sleeve with the second toothing has, wherein the switching ring and the sleeve are decoupled by a decoupling element over a predetermined path, in order to actuate the claw clutch arrangement, the sliding sleeve arrangement is started from a starting point, the sliding sleeve arrangement reaches a tooth-on-tooth point at which a tooth-on- Tooth position of the first teeth and the second teeth can exist, the sleeve is moved further from the tooth-on-tooth point at a maximum speed, the maximum speed being determined depending on the differential speed of the coupling body and the sliding sleeve arrangement and the length of the predetermined path .

DE 10 2017 202 081 A1 discloses a method for real-time monitoring of an electromagnetically actuated dog clutch, comprising a Magnetic armature, in which, based on simultaneous transient real-time estimates of the position of the magnetic armature, the time of a collision of one or more teeth of the claw clutch is determined in a first step, and the position of the magnetic armature at the time of the collision is determined in a second step, and in a third step, an evaluation of the position signal at the detected collision times takes place, as well as a determination of whether the collision occurred in a tooth-on-tooth position or in a different position of the claw clutch.

Out of DE 10 2005 012 308 A1 is a motor vehicle transmission control device with a means for establishing and / or releasing engagement of a toothing of a motor vehicle transmission and with a control unit for actuating a clutch, the clutch being suitable for transmitting a torque to a first component of the toothing and the control unit being intended for this purpose, to briefly adjust the clutch to a desired clutch position in order to release a tooth-on-tooth position of the toothing, in which the clutch transmits a torque pulse to the first component of the toothing, the control unit being intended to adjust the desired clutch position depending on a control signal to adapt the reaction signal of the motor vehicle transmission triggered by the control unit.

Summary of the invention

It is an object of the invention to provide a method for determining the wear of an electromechanically actuated claw clutch that avoids the problems described above and in particular enables an accurate and cost-effective determination of the actuator position.

The problem is solved by a method for determining the wear of an electromechanically actuated claw clutch with the features according to claim 1.

The actuator of the claw clutch comprises an electric motor which can pivot a toothed shift fork directly via a pinion, i.e. a gear, whereby the shift fork, when pivoted by the electric motor, covers an axial path in the direction of the axis of a sleeve in order to take the sleeve axially with it and from it a decoupled position to a coupled position of the claw clutch and/or vice versa, with current angles of the electric motor rotor characteristic of the wear of the claw clutch being determined during operation of the claw clutch.

According to the invention, current values of the following angle characteristic of the wear of the claw clutch are determined during operation of the claw clutch: Backlash angle (phiBL), i.e. a relative angle that indicates the total play of the actuator up to the sleeve.

According to the invention, the backlash angle (phiBL) is determined by transmitting a predetermined minimum torque to the shift fork during the coupled state by rotating with a defined voltage in the CW and CCW directions (i.e. clockwise and counterclockwise). until the shift fork rests on the sleeve, i.e. the sleeve blocks the pivoting movement of the shift fork, whereby the difference between these two angles in the CW and CCW directions corresponds to the backlash angle (phiBL).

According to the invention, a claw clutch is used which comprises an electromechanical actuator, with an electric motor, preferably a BLDC electric motor, which can directly pivot a toothed shift fork via a pinion. By pivoting the shift fork, it moves axially in the direction of the axis of a sleeve and usually takes the sleeve axially with it via a spring on the sleeve in order to bring it into the coupled or decoupled state.

In order to save the costs of a position sensor, the translation between the pinion and the toothed fork is designed so that the entire axial travel, including wear reserve, can be covered within one revolution of the motor rotor. In order to ensure that the actuator position is clearly determined at all times, the current total wear of the actuator system is determined.

According to the invention, current angles of the electric motor rotor that are characteristic of the wear of the claw clutch are determined during the operation of such a claw clutch, i.e. after the production and installation of the claw clutch, preferably in a motor vehicle, during normal operation of the clutch in the motor vehicle.

In order to be able to describe the system state functionally, four characteristic variables - described in more detail below - are preferably determined during operation, during the service life of the clutch, which can already be measured for the first time on an EOL (End of Line) test bench and in the NVM (Non volatile memory) of an ECU can be written.

The angles mentioned are preferably determined once at EOL, i.e. at the end of production of the coupling, and then updated according to the invention. Since the actuator system over the course of its As the service life increases, the initially determined angles become less and less consistent with the mechanical reality as the service life increases.

Furthermore, the different installation conditions in the vehicle and at the EOL can also lead to further deviations between EOL values and later real values, in particular due to axial displacement due to accumulated bearing clearance.

If the running, current system variables are not known, this leads to problems with adjustment, especially in the tooth-to-tooth area.

Wear is therefore continuously measured, preferably throughout the entire service life of the unit. For this purpose, the characteristic variables, preferably four, are also determined during vehicle operation, analogous to a preferred learning routine at the EOL. This means that the relevant tooth-to-tooth area is always searched for in the correct environment (TTC search area), and the current overall wear of the actuator is determined.

This makes it possible to take the wear of the actuator components into account in the operating strategy of the DCU (Decouple Unit) and thus maintain switching comfort and switching performance over the service life.

• - Beim Koppeln: ein höherer Schaltkomfort (der Regler wird im TTC-Bereich nicht aufziehen) und höhere Schaltgeschwindigkeit,
• - Beim Entkoppeln: exaktes Triggern der Muffen-Abbremsfunktion, sobald der Zahn-Überlappungsbereich verlassen wird,
• - Außerdem ist dadurch immer der tatsächliche mechanische Verschleiß bekannt und es kann ein Fehler gemeldet werden, bevor ein falscher Systemzustand ausgegeben wird.

The advantages of knowing the state of wear include:

• - When coupling: greater switching comfort (the controller will not open in the TTC range) and higher switching speed,
• - When decoupling: precise triggering of the sleeve braking function as soon as the tooth overlap area is left,
• - In addition, the actual mechanical wear is always known and an error can be reported before an incorrect system status is output.

Further developments of the invention are specified in the dependent claims, the description and the accompanying drawings.

• - Offset-Winkel (phiOfs), also ein absoluter Winkel, der angibt, wann die Muffe und/oder der Aktuator gegen einen Entkoppelt-Anschlag drückt. Dieser Winkel wird bevorzugt auch als Referenzwinkel für die Bestimmung des TTC-(Zahn-auf-Zahn)-Winkels (siehe unten) und des Full-Range-(Gesamtverdrehwinkel)-Winkels (siehe unten) verwendet. und/oder
• - TTC-Winkel (phiActTTC), also ein relativer Winkel, der einen Differenzwinkel angibt zwischen dem Offset-Winkel und einem Winkel, an dem die Muffe auf eine Zahn-Zahn-Position trifft, und/oder
• - Fullrange-Winkel (phiActFullRng), also ein relativer Winkel, der einen Differenzwinkel angibt, zwischen dem Offset-Winkel und einem Winkel, an dem die Muffe und/oder der Aktuator auf einen Gekoppelt-Anschlag trifft.

Preferably, current values of the following angles characteristic of the wear of the claw clutch are determined during operation of the claw clutch:

• - Offset angle (phiOfs), i.e. an absolute angle that indicates when the sleeve and/or the actuator presses against a decoupled stop. This angle is also preferably used as a reference angle for determining the TTC (tooth-on-tooth) angle (see below) and the full-range (total twist angle) angle (see below). and or
• - TTC angle (phiActTTC), i.e. a relative angle that indicates a difference angle between the offset angle and an angle at which the sleeve meets a tooth-to-tooth position, and/or
• - Full range angle (phiActFullRng), i.e. a relative angle that indicates a difference angle between the offset angle and an angle at which the sleeve and/or the actuator meets a coupled stop.

One or more of these four angles, but preferably all four, can be determined because together they define the system behavior.

Further variables relevant to the circuit, in particular positions, can then be derived from these variables.

Mean values are preferably calculated over a number of current values of the characteristic angles determined one after the other, as learning values of the characteristic angles.

The claw clutch is preferably installed in a motor vehicle and the current values of the angles characteristic of the wear of the claw clutch are determined during operation of the motor vehicle.

The offset angle (phiOfs) is preferably determined by pressing the sleeve against a decoupled stop with a defined tension profile. All games in the decoupled direction are used up. Preferably, the same parameterization is used for a first determination at EOL as for further determinations during normal operation. This angle is preferably taught first in each angle determination cycle, since the decoupled stop is always verified at the beginning.

The TTC angle (phiActTTC) is preferably determined by the fact that the position at which the actuator, which is operated with a predefined current limit, cannot be moved further within a certain range, namely the so-called TTC range (“stuck remains"), is saved. The current limitation in this area is preferably chosen so that it is as possible corresponds to the resulting current in the EOL routine. When determining the TTC positions, all games in the coupled direction are used up - the system backlash, phiBL, is therefore included. The first determination of the TTC angle, at the EOL, can be done using a routine that presses against the tooth-to-tooth position with a defined tension. The mechanical establishment of this position can be guaranteed by the EOL routine.

The full-range angle (phiActFullRng) is preferably determined by pressing the sleeve against a coupled stop with a defined tension profile. This value also corresponds to the significant overall wear of the system.

In order to ensure the robustness of the learned values, learning values averaged over a preferably variable (depending on special events such as ECU replacement) number of learning events (anzLernEvents) are preferably used for the calculation models, i.e. for the nth determination of an angle phiXY: $$\begin{array}{l}\text{phiXYLearn}\left(\text{n}\right)=\left(\text{phiXYLearn}\left(\text{n}-1\right)*(\text{number of learning events}-1\right)+\\ \text{phiXYCurrently})/\text{number of learning events}\end{array}$$

Brief description of the drawings

• 1 ist eine schematische Darstellung der Auswirkungen des Verschleißes auf die vier charakteristischen Winkel, zu den Zeitpunkten a) EOL (End of Line), b) nach Verbau im Fahrzeug (neu) und c) im Fahrzeug nach längerem Betrieb.
• 2 ist eine schematische Darstellung der Ermittlung des Offset-Winkels (phiOfs).
• 3 ist eine schematische Darstellung der Ermittlung des Fullrange-Winkels (phiActFullRng).
• 4 ist eine schematische Darstellung der Ermittlung des Backlash-Winkels (phiBL).

The invention is described below by way of example with reference to the drawings.

• 1 is a schematic representation of the effects of wear on the four characteristic angles, at the times a) EOL (End of Line), b) after installation in the vehicle (new) and c) in the vehicle after long-term operation.
• 2 is a schematic representation of the determination of the offset angle (phiOfs).
• 3 is a schematic representation of the determination of the full-range angle (phiActFullRng).
• 4 is a schematic representation of the determination of the backlash angle (phiBL).

Detailed description of the invention

In the 1 They show the effects of wear on the four characteristic angles at the times a) EOL (End of Line), b) after installation in the vehicle (new) and c) in the vehicle after long-term operation.

The coupled position 4 with its coupled stop 10 is shown on the left and the decoupled position 3 with its decoupled stop 9 is shown on the right. Between the two positions coupled 4 and decoupled 3 there is a tooth-on-tooth position (TTC position ) 16, with a tooth-on-tooth “stop” 5, which describes the beginning of the tooth overlap area, which is important for coupling and uncoupling.

The angles offset angle phiOfs, TTC angle phiActTTC, full range angle phiActFullRng and backlash angle phiBL are shown in the three different wear states a) b) and c). The offset angle phiOfs is an absolute angle that indicates when the sleeve 2 and/or the actuator presses against the decoupled stop 9. It is also the reference angle for determining the TTC (tooth-on-tooth) angle and the FullRng (total twist angle) angle. The TTC angle phiActTTC is a relative angle that indicates a difference angle between the offset angle phiOfs and an angle at which the sleeve 2 meets a tooth-tooth stop 5, i.e. the beginning of the tooth-tooth overlap area. The full-range angle phiActFullRng is a relative angle that indicates a difference angle between the offset angle phiOfs and an angle at which the sleeve 2 and/or the actuator meets a coupled stop 10. The backlash angle phiBL is a relative angle that indicates the total play of the actuator, in particular the shift fork 1, up to the sleeve 2.

In the lower left area of the 1 is also shown schematically where the TTC search range 8 can be defined, which describes the possible range of the tooth-tooth position at the end of the TTC angle phiActTTC, in the non-real uncompensated case 6, with EOL angles (state a )), and in the compensated case 7, if the determined real angles in the current state of wear of the clutch are assumed (state c)). The TTC search area 8 can be made different sizes depending on other known properties of the clutch, for example larger after replacing the ECU (Electronic Control Unit).

2 is a schematic representation of the determination of the offset angle phiOfs.

The diagram shows the time t on the x-axis and the current angle phiAct (top) as well as the specified voltage uReq (bottom) on the y-axis. For the angle phiAct, the angle of the decoupled stop 9 is also shown, as well as the coupled stop 10 - each with a dashed line.

In front of the decoupled stop 9 there is a decoupled position 3 (dash-dotted) and in front of the coupled stop 10 there is a coupled position 4 (also dash-dotted).

The three arrows below the x-axis indicate different phases of the determination, namely the search period 11, the holding period 12 and the learning phase 13. During the search period 11 and holding period 12, the actuator system 14 is "overpressed", at the end of which the load is relieved Actuator 15 takes place.

The offset angle phiOfs is determined by pressing the sleeve 2 with a defined voltage profile uReq against a decoupled stop 9 (“over-pressing” the actuator 14). All games in the decoupled direction are used up. After a short countermovement to relieve the load on the actuator 15, the current value of the offset angle phiOfs can be determined as the current angle phiAct in the learning phase 13.

Preferably, the same parameterization is used for a first determination at EOL as for further determinations during normal operation. This angle is preferably taught first in each cycle of determining angles, since the decoupled stop 9 is always verified at the beginning.

3 is a schematic representation of the determination of the full-range angle phiActFullRng. The figure largely corresponds to that 2 , whereby the sleeve 2 is pressed against the coupled stop 10, instead of against the decoupled stop 9: The sleeve 2 is pressed against the coupled stop 10 with a defined voltage profile uReq (“over-pressing” the actuator 14. All Games in the coupled direction have been used up. After a short countermovement when relieving the load on the actuator 15, the current value of the full-range angle phiActFullRng can be determined in the learning phase 13 as the difference angle between the offset angle phiOfs and the current angle phiAct.

The TTC angle (phiActTTC) is determined by the fact that the position at which the actuator, which is operated with a predefined current limitation, cannot be moved further within a certain range, namely the so-called TTC search range 8, i.e “gets stuck” is saved. The current limitation in this area is selected so that it corresponds as closely as possible to the resulting current in the corresponding EOL routine. When determining the TTC positions, all games in the coupled direction are used up, so the system backlash, phiBL, is included. The TTC angle at the time EOL is determined via a routine that presses against the tooth-tooth stop 5 with a defined tension. The mechanical establishment of this position during the EOL determination is guaranteed by an EOL routine.

4 finally shows a schematic representation of the determination of the backlash angle phiBL. The same sizes are shown in the x and y axes as in 2 and 3 . In addition, the transmitted clutch torque M is shown on the y-axis, below uReq. M1 represents a clutch torque >= 20 Nm, M2 a clutch torque <= -20 Nm and M0 a clutch torque of 0 Nm and the state of blockage of sleeve 2 by the EOL engine torque.

The backlash angle phiBL is determined by transmitting a predetermined minimum torque M to the shift fork 1 during the coupled state 4 by rotating with a defined voltage uReq in the CW and CCW directions, with a positive motor torque M1 or negative Motor torque M2, until the shift fork 1 is in contact with the sleeve 2, i.e. the sleeve 2 blocks the pivoting movement of the shift fork 1. The difference between the two angles phiAct in the CW and CCW directions corresponds to the angle phiBL.

Reference symbol list

1

Shift fork

2

sleeve

3

Decoupled position

4

Coupled position

5

Tooth-to-tooth stop (TTC position)

6

uncompensated case

7

compensated case

8th

TTC search area

9

Decoupled stop

10

Coupled stop

11

Search duration

12

Holding period

13

Learning phase

14

Overpressing the actuators

15

Relieving the actuator system

16

Tooth-to-tooth position (TTC position)

M

Clutch torque

M1

Clutch torque >= 20 Nm

M2

Clutch torque <= -20 Nm

M0

Coupling torque = 0 Nm, sleeve 2 blocked by the EOL engine torque

uReq

specified voltage

phiOfs

Offset angle

phiActTTC

Tooth-on-tooth angle = TTC angle

phiActFullRng

Full range angle

phiBL

Backlash angle

Claims (7)

Method for determining the wear of an electromechanically actuated claw clutch, wherein the actuator of the claw clutch comprises an electric motor which can directly pivot a toothed shift fork (1) via a pinion, the shift fork (1) having an axial path in the direction of the axis when pivoted by the electric motor a sleeve (2) in order to entrain the sleeve (2) axially and to move it from a decoupled position (3) to a coupled position (4) of the claw clutch and/or vice versa, with current, Angles (phiOfs, phiActTTC, phiActFullRng, phiBL) of the electric motor rotor that are characteristic of the wear of the claw clutch are determined, characterized in that current values of the following angle characteristic of the wear of the claw clutch are determined during operation of the claw clutch: Backlash angle (phiBL) , i.e. a relative angle that indicates the total play of the actuator up to the sleeve (2), the backlash angle (phiBL) being determined by the fact that a predetermined minimum torque (M) is applied to the shift fork (1.) during the coupled state (4). ) is transferred by turning with a defined voltage (uReq) in the CW and CCW direction, i.e. clockwise and counterclockwise, until the switching fork (1) is in contact with the sleeve (2), i.e. the sleeve (2) the pivoting movement of the shift fork (1) is blocked, whereby the difference between these two angles in the CW and CCW directions corresponds to the backlash angle (phiBL). Procedure according to Claim 1 , characterized in that during operation of the claw clutch, current values of the following angles characteristic of the wear of the claw clutch are determined: - Offset angle (phiOfs), i.e. an absolute angle that indicates when the sleeve (2) and/or the actuator presses against a decoupled stop (9), and/or - tooth-on-tooth angle, TTC angle (phiActTTC), i.e. a relative angle that indicates a difference angle between the offset angle (phiOfs) and an angle, where the sleeve (2) meets a tooth-tooth stop (5), and/or - full-range angle (phiActFullRng), i.e. a relative angle that indicates a difference angle between the offset angle (phiOfs) and a Angle at which the sleeve (2) and/or the actuator meets a coupled stop (10). Method according to one of the preceding claims, characterized in that mean values are calculated over a number of current values of the characteristic angles (phiOfs, phiActTTC, phiActFullRng, phiBL) determined in succession. Method according to one of the preceding claims, characterized in that the claw clutch is installed in a motor vehicle and the current values of the angles (phiOfs, phiActTTC, phiActFullRng, phiBL) characteristic of the wear of the claw clutch are determined during operation of the motor vehicle. Method according to one of the preceding Claims 2 until 4 , characterized in that the offset angle (phiOfs) is determined by pressing the sleeve (2) with a defined voltage profile (uReq) against a decoupled stop (9). Method according to one of the preceding Claims 2 until 5 , characterized in that the TTC angle (phiActTTC) is determined by not changing the position at which the actuator, which is operated with a predefined current limit, within a certain range, namely the so-called TTC search range (8). can be moved, is saved. Method according to one of the preceding Claims 2 until 6 , characterized in that the full-range angle (phiActFullRng) is determined by pressing the sleeve (2) with a defined voltage profile (uReq) against a coupled stop (10).

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