DE102023207175B3 - Method for determining a synchronization point of a coupling process of a claw clutch - Google Patents

Abstract

Method for determining a synchronization point P_sact during a coupling process of a claw clutch 1, wherein an electric machine 2 can be connected in a driving manner via the claw clutch 1 to a component to be driven, the claw clutch 1 having at least a first coupling element 1a and an axially movable second coupling element 1b, the electrical Machine 2 is speed-controlled and so a predetermined differential speed between the two coupling elements 1a, 1b is set and the axial movement of the second coupling element 1b of the claw clutch 1 is divided into at least two adjustment phases V1, V2, namely a first adjustment phase V1 and a second adjustment phase V2 , whereby a first is achieved by determining an average torque M1_av and a maximum torque M1_max of the electric machine 2 during the first adjustment phase V1 and by comparing the torque values M1_av, M1_max determined in the first adjustment phase V1 with a torque M2 determined in the second adjustment phase V2 Criterion is generated to detect a preliminary synchronization point P_spre and a second criterion is generated to set the preliminary synchronization point P_spre as the actual synchronization point P_sact.

Description

Field of invention

The present invention relates to a method for determining a synchronization point during a coupling process of a claw clutch, wherein an electric machine can be connected to a component to be driven via the claw clutch, wherein the claw clutch has at least a first clutch element and an axially movable second clutch element and wherein the electric machine is speed-controlled and thus a predetermined differential speed is set between the two clutch elements.

Furthermore, the present invention relates to the use of a method according to the invention in an electric or hybrid motor vehicle.

State of the art

In electric and hybrid motor vehicles, so-called claw clutches are often used to transmit rotational movements or torque from an electric machine via a gearbox to a drivable motor vehicle axle. The claw clutch has two coupling elements, with a first coupling element being connected in a drive-effective manner, for example, to the electric machine and the second coupling element to the axle of the motor vehicle to be driven. In order to be able to close the claw clutch on a moving vehicle with little wear and noise, it is necessary to synchronize the speed of the two claw elements. In electric and hybrid vehicles, this is usually done actively via the electric machine by setting a defined speed difference between the clutch elements of the dog clutch. That is, in order to engage the claw clutch, the electric machine is controlled by a control device in such a way that an almost constant differential speed band results between the electric machine and the axle of the motor vehicle to be driven.

A “synchronization point” of the claw clutch is, in the course of a coupling or closing process of the claw clutch, the point in time at which initial contact takes place in the form of a frictional or positive connection between the two coupling elements of the claw clutch. In relation to an application of the claw clutch in an electric or hybrid motor vehicle described above, the synchronization point therefore represents the point in time from which the driving electric machine and the axle of the motor vehicle to be driven are connected in a driving manner.

Precise knowledge of the synchronization point of the coupling elements of the dog clutch results in several advantages that have a positive effect on shifting comfort, the switching time and the NVH ("Noise Vibration Harshness") behavior during the shifting process of the dog clutch.

The document DE 10 2016 114 105 A1 For example, discloses a method for determining a synchronous point of a synchronous clutch of a motor vehicle transmission, which is connected on the input side to an electric machine and which includes a plurality of synchronous clutches, each of which has a drive member connected to the electric machine and an output member connected to an output shaft and which can be actuated from an open position into a closed position by means of an associated clutch actuator, the method comprising steps 1.) detecting an output speed of the output member of a synchronous clutch, the synchronization point of which is to be determined; 2.) regulating a drive speed of the drive member of the synchronous clutch to a synchronous point determination speed that is unequal to the output speed; 3.) Activating the shift clutch actuator to actuate the synchronous shift clutch from the open position towards the closed position; and 4.) determining the synchronization point of the synchronous clutch by monitoring at least one operating parameter, the synchronization point being determined when the operating parameter changes absolutely, changes relative to an operating parameter comparison value and / or changes dynamically.

Summary of the invention

It is an object of the invention to provide a method for the simple and exact determination of a synchronization point during a coupling process of a claw clutch, via which a driving connection can be established between an electrical machine and a component to be driven.

Furthermore, it is an object of the present invention to provide an advantageous use of the method according to the invention.

This need can be met by the subject matter of the present invention according to independent claims 1 and 3. Advantageous embodiments of the present invention are described in the dependent claims.

The method according to the invention is used to determine a synchronization point during a coupling process of a claw clutch, wherein an electric machine can be connected in a drive-effective manner via the claw clutch to a component to be driven.

According to the invention, the claw clutch has at least a first clutch element and an axially movable second clutch element.

According to the present invention, the electric machine is speed-controlled - in this way, a predetermined differential speed is set between the two clutch elements.

According to the invention, the axial movement of the second coupling element of the claw clutch is divided into at least two adjustment phases, namely a first adjustment phase and a second adjustment phase.

According to the present invention, a first criterion is generated by determining an average and maximum torque of the electric machine during the first adjustment phase and by comparing the torque values determined in the first adjustment phase with a torque detected in the second adjustment phase in order to determine a provisional synchronization point and generates a second criterion to set the preliminary synchronization point as the actual synchronization point.

• - Einstellen der vorbestimmten Differenzdrehzahl zwischen den beiden Kupplungselementen der Klauenkupplung über die elektrische Maschine,
• - Berechnung des durchschnittlichen Drehmoments der elektrischen Maschine in der ersten Verstellphase des zweiten Kupplungselements der Klauenkupplung,

• - Bestimmung des maximalen Drehmoments der elektrischen Maschine in der ersten Verstellphase der Klauenkupplung,
• - Zwischenspeicherung des berechneten durchschnittlichen Drehmoments und des bestimmten maximalen Drehmoments der elektrischen Maschine in der ersten Verstellphase der Klauenkupplung,
• - Erfassen des Drehmoments der elektrischen Maschine während der zweiten Verstellphase der Klauenkupplung und gleichzeitiger Vergleich des erfassten Drehmoments mit dem in der ersten Verstellphase bestimmten maximalen Drehmoment,
• - Zwischenspeicherung des Zeitpunkts und der Position des zweiten Kupplungselements bei erstmaligem Überschreiten des in der ersten Verstellphase bestimmten maximalen Drehmoments in der zweiten Verstellphase als vorläufigen Synchronisierungspunkt,
• - Berechnung des durchschnittlichen Drehmoments in der zweiten Verstellphase ab dem erfassten vorläufigen Synchronisierungspunkt,
• - Vergleich des in der zweiten Verstellphase, ab dem erfassten vorläufigen Synchronisierungspunkt, berechneten durchschnittlichen Drehmoments mit dem in der ersten Verstellphase berechneten und zwischengespeicherten durchschnittlichen Drehmoment,
• - Hinterlegen des vorläufigen Synchronisierungspunkts als tatsächlichen Synchronisierungspunkt, wenn das in der zweiten Verstellphase, ab dem erfassten vorläufigen Synchronisierungspunkt, berechnete durchschnittliche Drehmoment um einen definierten Betrag höher ist als das in der ersten Verstellphase berechnete durchschnittliche Drehmoment.

When there is a coupling requirement for the claw clutch, the method according to the invention preferably has at least the following steps:

• - Setting the predetermined differential speed between the two coupling elements of the claw clutch via the electric machine,
• - Calculation of the average torque of the electric machine in the first adjustment phase of the second coupling element of the claw clutch,

• - Determination of the maximum torque of the electric machine in the first adjustment phase of the claw clutch,
• - intermediate storage of the calculated average torque and the determined maximum torque of the electric machine in the first adjustment phase of the claw clutch,
• - detecting the torque of the electric machine during the second adjustment phase of the claw clutch and simultaneously comparing the detected torque with the maximum torque determined in the first adjustment phase,
• - Intermediate storage of the time and position of the second coupling element when the maximum torque determined in the first adjustment phase is exceeded for the first time in the second adjustment phase as a provisional synchronization point,
• - Calculation of the average torque in the second adjustment phase from the recorded provisional synchronization point,
• - Comparison of the average torque calculated in the second adjustment phase, from the detected provisional synchronization point, with the average torque calculated and buffered in the first adjustment phase,
• - Storing the provisional synchronization point as the actual synchronization point if the average torque calculated in the second adjustment phase, from the recorded provisional synchronization point, is higher by a defined amount than the average torque calculated in the first adjustment phase.

According to the present invention, the method according to the invention is used in an electric or hybrid motor vehicle.

By means of the method according to the invention for determining a synchronization point during a coupling process of a claw clutch, which is connected to an electric machine for driving purposes, in addition to a reduction in the switching time of the claw clutch, improved NHV and vibration behavior can be achieved. Furthermore, the wear of the coupling elements of the claw clutch can be reduced by precisely knowing the synchronization point of the claw clutch.

By using the method according to the invention in an electric or hybrid motor vehicle, especially in the area of an electric axle arrangement, driver safety can also be increased.

Brief description of the drawings

• 1 zeigt eine schematische Detaildarstellung eines Kraftfahrzeugantriebs mit einer elektrischen Maschine und einem Getriebe mit einer entkoppelten Klauenkupplung.
• 2 zeigt Diagramme von Parametern zur Bestimmung des Synchronisierungspunkts einer Klauenkupplung in einem Aufbau entsprechend 1.

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

• 1 shows a schematic detailed representation of a motor vehicle drive with an electric machine and a gearbox with a decoupled dog clutch.
• 2 shows diagrams of parameters for determining the synchronization point of a dog clutch in a structure accordingly 1 .

Detailed description of the invention

In 1 A detail of a motor vehicle drive, namely a gear transmission 3 and an electric machine 2, is shown schematically by way of example. The method according to the invention is based on the in 1 The topology shown is described, but can also be used with other gear topologies, such as a planetary gear.

The electric machine 2 is connected to an input shaft 4 of the gear transmission 3 in a driving manner. Furthermore, the electrical machine 2 is connected to an inverter 9 for energizing the electrical machine 2. The inverter 9 has a control unit 10. The control unit 10 has the task of sending a target speed specification to the inverter 9. The inverter 9 then independently regulates the electrical machine 2 to the required speed.

The gear transmission 3 can have several gear stages, of which in 1 However, only one gear stage 5, which has a fixed gear 5a and an idler gear 5b, is shown. Both the fixed gear 5a and the idler gear 5b are designed as spur gears. The fixed gear 5a is arranged on the input shaft 4 of the gear transmission 3. The idler gear 5b is arranged on an output shaft 6 of the gear transmission 3.

Furthermore, an output gear 7 is arranged on the output shaft 6 of the gear transmission, which is drivingly connected to an axle of the motor vehicle (not shown), more precisely to a differential gear (not shown) arranged on the axle.

The idler gear 5b can be coupled in a rotationally fixed manner to the output shaft 6 of the gear transmission 3 by means of a claw clutch 1.

The claw clutch 1 has a first coupling element 1a, namely a claw element, and an axially movable second coupling element 1b, namely a sliding sleeve. Subsequently, the reference number “1a” is also used for the claw element as the first coupling element 1a. The reference number “1b” is also used for the sliding sleeve as the second coupling element 1b.

The claw element 1a is connected to the idler gear 5b in a rotationally fixed and axially fixed manner. The sliding sleeve 1b is translationally displaceable in the direction of the claw element 1a and is connected in a rotationally fixed manner to the output shaft 6 of the gear transmission 3.

By engaging the sliding sleeve 1b in the claw element 1a, the idler gear 5b can therefore be connected in a rotationally fixed manner to the output shaft 6 of the gear transmission 3, in order to enable power transmission from the electric machine 2 via the gear stage 5 to the output shaft 6 of the gear transmission 3, whereby the fixed gear 5a is held non-rotatably on the input shaft 4 of the gear transmission 3.

To remove the sliding sleeve 1b from the in 1 To transfer the decoupled position shown into a coupled position, i.e. to carry out a coupling process, the sliding sleeve 1b is connected to an actuator unit 8 in a driving manner. The actuator unit 8 in the present case comprises a shift drum (not shown in detail).

By rotating the shift drum of the actuator unit 8, the sliding sleeve 1b can be displaced in the direction of the claw element 1a in order to couple the sliding sleeve 1b to the claw element 1a (coupling process). Likewise, the sliding sleeve 1b can be decoupled from the claw element 1a by rotating the shift drum of the actuator unit 8 (decoupling process).

For this purpose, the sliding sleeve 1b has a guide element which is guided in a shift gate of the shift drum in order to convert a rotation of the shift drum into a translational displacement of the guide element together with the sliding sleeve 1b (not shown).

The method according to the invention for determining a synchronization point P_s _act of the claw clutch 1 is described below using the 2 described.

Diagram I 2 shows the position P of the shift drum of the actuator unit 8 in degrees [°], based on a rotation of the shift drum about its own axis, plotted over time t in seconds [s].

The diagram II 2 shows the torque curve M of the electric machine 2 when the speed of the electric machine 2 is controlled in Newton meters [Nm] plotted over time t in seconds [s].

The coupling process between the shift sleeve 1b of the claw clutch 1 and the claw element 1a of the claw clutch 1 begins Start time t_0 and is completed at the end time t_end. The diagrams according to 2 therefore describe the manner in which the sliding sleeve 1b is moved starting from a starting position P_0 at time t_0, ie a decoupled state of the claw clutch 1, until reaching an end position P_end at time t_end, ie the coupled state of the claw clutch 1.

A first adjustment phase V1 begins at time t_1 and ends at time t_2.

During the first adjustment phase V1 of the sliding sleeve 1b, no contact of the sliding sleeve 1b with the claw element 1a is to be expected. The first adjustment phase V1 can also be referred to as the “implausible synchronization range” of the sliding sleeve 1b.

During the first adjustment phase V1, a speed difference is specified between the idler gear 5b and the output shaft 6 to be synchronized, on which the idler gear 5b is arranged, the idler gear 5b being coupled to the electric motor 2 via the fixed gear 5a arranged on the input shaft 4 to set a speed of the idler gear 5b. Specifying the speed difference between the idler gear 5b and the output shaft 6 to be synchronized also means specifying a speed difference between the sliding sleeve 1b of the claw clutch 1, which is non-rotatably coupled to the output shaft 6, and the claw element 1a, which is held non-rotatably on the idler gear 5b .

During the first adjustment phase V1, the sliding sleeve 1b is displaced starting from the starting position P_0 up to a first position P_1. The first position P_1 is a defined intermediate position of the sliding sleeve 1b before contacting the claw element 1a of the idler gear 5a.

The sliding sleeve 1b of the claw clutch 1 is moved in the direction of the claw element 1a of the idler gear 5b from the starting position P_0 to the first position P_1 by means of the controlled shift drum of the actuation unit 8.

During the first adjustment phase V1, the torque is detected during the first adjustment phase M1. Furthermore, an average torque M1_av is calculated during the first adjustment phase V1 and the maximum torque M1_max is determined during the first adjustment phase V1. If the first adjustment phase V1 is successfully completed without an abort criterion, for example if the desired differential speed between the sliding sleeve 1b and the claw element 1a is not set, the calculated values for the average torque M1_av and the specific value for the maximum torque M1_max during the first adjustment phase V1 is temporarily stored in the storage unit of the control unit 10.

Following the first adjustment phase V1, a second adjustment phase V2 follows. The second adjustment phase V2 begins at time t_2 and ends at time t_3.

As part of the second adjustment phase V2, contact between the sliding sleeve 1b and the claw element 1a is to be expected. The second adjustment phase V2 can also be referred to as the “plausible synchronization range” of the sliding sleeve 1b.

During the second adjustment phase V2, the sliding sleeve is moved from the first position P_1 to a second position P_2. The second position P_2 is a further intermediate position of the sliding sleeve 1b after the sliding sleeve 1b has been coupled into the claw element 1a of the idler gear 5b.

Moving the sliding sleeve 1b of the claw clutch 1 in the direction of the claw element 1a of the idler gear 5b from the first position P_1 up to the
The second position P_2 takes place by means of the controlled shift drum of the actuation unit 8.

During the second adjustment phase V2, the torque is detected during the second adjustment phase M2 and at the same time the detected torque M2 is compared with the maximum torque M1_max detected in the first adjustment phase V1.

As soon as the detected torque exceeds the maximum torque M1_max from the first adjustment phase V1 once during the second adjustment phase V2, the position P_s of the sliding sleeve 1b is buffered at this time t_s as a provisional synchronization point P_s _pre . The average torque M2_av is then calculated from the time t_s to the end of the second adjustment phase V2, i.e. until the time t_3. If the calculated average torque M2_av in the period from time t_s to time t_3 is higher by a certain amount than the average torque M1_av calculated in the first adjustment range V1, then the previously stored position P_s at time t_s is saved as the actual synchronization point P_s _act .

Following the second adjustment phase V2, the complete phase follows in the period t_3 to t_end Engagement of the sliding sleeve 1b in the claw element 1a.

Reference symbol list

1

Claw coupling

1a

First coupling element (claw element)

1b

Second coupling element (sliding sleeve)

2

Electric machine

3

Gear transmission

4

input shaft

5

gear stage

5a

Fixed gear

5b

idler wheel

6

input shaft

7

output gear

8th

Actuation unit

9

Inverters

10

Control unit

V1

First adjustment phase

V2

Second adjustment phase

M1_av

Average torque during the first adjustment phase

M2_av

Average torque during the second adjustment phase

M1_max

Maximum torque during the first adjustment phase

M1

Torque during the first adjustment phase

M2

Torque during the second adjustment phase

P_spre

Temporary sync point

P_sact

Actual sync point

t

Time

t_s

Time of synchronization point

t_0

Start time

t_end

end time

t_1, t_2, t_3

(Interim) times

P

Position (of the sliding sleeve)

P_s

Position of the synchronization point

P_0

Starting position

P_end

Final position

P_1

First position

P_2

Second position

Claims (3)

Method for determining a synchronization point P_s _act during a coupling process of a claw clutch 1, wherein an electric machine 2 as a driving component can be connected in a drive-effective manner via the claw clutch 1 to a component to be driven, the claw clutch 1 having at least a first coupling element 1a and an axially movable second coupling element 1b has, wherein the electric machine 2 is speed-controlled and a predetermined differential speed is set between the two coupling elements 1a, 1b and wherein the axial movement of the second coupling element 1b of the claw clutch 1 is divided into at least two adjustment phases V1, V2, namely a first adjustment phase V1 and a second adjustment phase V2, wherein via a determination of an average torque M1_av and a maximum torque M1_max of the electric machine 2 during the first adjustment phase V1 and via a comparison of the torque values M1_av, M1_max determined in the first adjustment phase V1 with one in the second adjustment phase V2 certain torque M2, a first criterion is generated to detect a preliminary synchronization point P_s _pre and a second criterion is generated to set the preliminary synchronization point P_s _pre as the actual synchronization point P_s _act . Procedure according to Claim 1 , characterized in that the method has at least the following steps when there is a coupling request to the claw clutch 1: - Setting the predetermined differential speed between the two clutch elements 1a, 1b of the claw clutch 1 via the electric machine 2, - Calculating the average torque M1_av of the electric machine 2 in the first adjustment phase V1 of the second coupling element 1b of the dog clutch 1, - determination of the maximum torque M1_max of the electric machine 2 in the first adjustment phase V1 of the second coupling element 1b of the dog clutch 1, - intermediate storage of the calculated by average torque M1_av and the specific maximum torque M1_max of the electric machine 2 in the first adjustment phase V1 of the second claw element 1b of the claw clutch 1, - detecting the torque M2 of the electric machine 2 during the second adjustment phase V2 of the second clutch element 1b of the claw clutch 1 and simultaneous comparison of the detected torque with the maximum torque M1_max determined in the first adjustment phase V1, - intermediate storage of the time t_s and the position P_s of the second coupling element 1b when the maximum torque M1_max determined in the first adjustment phase V1 is exceeded for the first time in the second adjustment phase V2 as a provisional synchronization point P_s _pre , - Calculation of the average torque M2_av in the second adjustment phase V2 from the detected preliminary synchronization point P_s _pre , - Comparison of the average torque M2_av calculated in the second adjustment phase V2, from the detected preliminary synchronization point P_s _pre , with that calculated in the first adjustment phase V1 and buffered average torque M1_av, - storing the provisional synchronization point P_s _pre as the actual synchronization point P_s _act if the average torque M2_av calculated in the second adjustment phase V2, from the detected provisional synchronization point P_s _pre , is higher than the average calculated in the first adjustment phase V1 Torque M1_av. Using a method according to Claim 1 or 2 , in an electric or hybrid vehicle.

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