DE102018222026A1 - Error detection procedure when shifting a transmission - Google Patents

Abstract

The present invention relates to a method for fault detection when adjusting a shift element for a shifting process in a transmission, comprising the steps: adjusting the shifting element to carry out the shifting process, determining an actual shifting path (13, 16) during the shifting of the shifting element, comparing the determined actual switching path (13, 16) with a target switching path (12, 15) and recognizing an error when adjusting the switching element if there is a discrepancy between the target switching path (12, 15) and the determined actual switching path (13 , 16) is present.

Description

The present invention relates to a method for detecting faults when adjusting a switching element in a transmission in accordance with the type defined in more detail in patent claim 1. Furthermore, the invention relates to a control device for carrying out the method and a corresponding computer program product.

It is known that in the case of automated transmissions, a desired gear is engaged and disengaged by a transmission actuator which is actuated, for example, electromechanically, hydraulically or pneumatically. A positive connection between a gear wheel and an associated shaft is made by means of a clutch as a switching element, which is axially displaceably mounted on the shaft. To engage the gear, the clutch clutch is shifted axially on the shaft by the gear actuator using a shift mechanism until the clutch and the gear wheel mesh. The distance traveled by the switching element is detected as the end position or stop position by means of a displacement sensor and transmitted to control electronics which control the transmission actuator accordingly.

The DE 10 2011 006 560 A1 discloses a method for fault detection when shifting an automated transmission. An end position of a switching mechanism actuated during shifting is determined with the aid of a stop position, the measured path to the stop position or the stop position being compared as a first criterion for fault detection with a stored maximum gear-unspecific path to the stop position. As a second criterion for error detection, a path change between the measured path to the stop position and a stored gear-specific path to the stop position is determined and evaluated accordingly. If the criteria for error detection are available, an appropriate error reaction is triggered.

With this procedure, however, the problem arises that the stop positions of the switching mechanism in the transmission can change due to wear and temperature influences. A wear and temperature-related change in a stop position can still amount to several millimeters despite taking into account appropriate compensation, which means that the functionality of the gearshift mechanism for shifting transmission gears based on the evaluation of stop positions is not available in all situations.

The present invention is based on the object of proposing a method for fault detection when shifting a transmission of a vehicle, with which the fault detection is improved. In addition, a corresponding control device and a computer program product for carrying out the method are to be specified.

This object is solved by the claims. From a procedural point of view, this object is achieved by the features of patent claim 1. A control device and a computer program product are also the subject of the further independent patent claims. Advantageous further developments are the subject of the subclaims and the following description and the drawings. Features that are described in connection with the method should also apply in connection with the control device according to the invention and the computer program product according to the invention and in each case vice versa, so that reference can always be made to one another with respect to the disclosure of the individual aspects of the invention.

• - Verstellen des Schaltelements zum Ausführen eines Schaltvorgangs,
• - Ermitteln eines Ist-Schaltwegverlaufs während des Verstellens des Schaltelements,
• - Vergleichen des ermittelten Ist-Schaltwegverlaufs mit einem Soll-Schaltwegverlauf und
• - Erkennen eines Fehlers beim Verstellen des Schaltelements, wenn eine Abweichung zwischen dem Soll-Schaltwegverlauf und dem ermittelten Ist-Schaltwegverlauf vorliegt.

According to the present invention, a method for fault detection when adjusting a shift element in a transmission is provided. The process includes the following steps:

• - adjusting the switching element to carry out a switching process,
• Determining an actual switching path during the adjustment of the switching element,
• - Comparing the determined actual shift path with a target shift path and
• - Detection of an error when adjusting the switching element if there is a discrepancy between the target shift path curve and the determined actual shift path curve.

A transmission here denotes in particular a multi-speed transmission in which a plurality of gear ratios, that is to say fixed gear ratios between two shafts of the transmission, can preferably be switched automatically by switching elements. Such transmissions are used primarily in vehicles in order to suitably adapt the speed and torque output characteristics of the drive unit to the driving resistances of the vehicle. By appropriately controlling the shifting elements, the transmission can be brought into a neutral position, in which the internal combustion engine is separated from the output. The switching element can be a positive-locking switching element. The switching element can in particular be designed as a gear wheel or clutch.

The switching process is preferably to be understood as a process in which the Switching element with another switching element, in particular a gear, is brought into operative connection. As part of the switching process, the transmission changes from a first switching state to a second switching state. A shift operation can therefore be understood to mean shifting from one gear to another gear, shifting from one gear to a neutral position and shifting from a neutral position to a gear.

The switching element can be adjusted by means of an adjusting device, which can be designed as a switching actuator. The shift actuator can be designed as a hydraulically or pneumatically actuated actuating cylinder or as an electrical actuator, by means of which a shift mechanism of the transmission for adjusting the shift element is actuated during a shift process.

The course of the switching path can be determined, for example, by detecting the position of the switching element by means of a displacement sensor system during the adjustment of the switching element. The displacement sensor system can be designed, for example, as a displacement sensor, which can be arranged on the shift mechanism of the transmission, such as the shift actuator, a shift rail or a shift fork.

An error when adjusting the switching element can be identified by means of an evaluation unit, for example a computing unit of a control unit, by comparing the target switching path profile with the determined actual switching path profile.

Because the proposed method for error detection takes into account not only the stop positions but also the switching path of the switching element during the adjustment of the switching element, an error when adjusting the switching element, such as a broken switching mechanism, can be detected with greater certainty.

Within the scope of the method according to the invention, it can be provided that the actual switching path curve is determined as soon as the actuation of the adjusting device for actuating the switching element begins and until the target position of the switching element is reached. In other words, the entire switching path course of the switching element is considered in the method for error detection.

The gearbox can be, for example, a synchronized gearbox with synchronized switching elements or an unsynchronized gearbox with unsynchronized switching elements or a partially synchronized gearbox with both synchronized and unsynchronized switching elements. Depending on the design of the switching element, there is a corresponding switching path curve when the switching element is adjusted. It is therefore further provided that for each of the shift elements present in the transmission or for each of the type of shift elements present in the transmission, a target shift path curve is stored, which is compared with the determined actual shift path curve when the respective shift element is actuated. The set shift path course for the shift elements present in the transmission is preferably stored in a memory of the control unit.

Thus, in one embodiment of the invention it is provided that the target shift path for the engagement of a gear in a synchronized shift element of the transmission during the adjustment of the speeds of the gear elements to be synchronized has an area with an at least approximately constant course, which takes into account in the error detection becomes. When switching a synchronized switching element, a so-called synchronization point is reached during the adjustment of the switching element, at which synchronizing elements of the synchronized switching element come into contact with one another. The synchronizing elements can be designed, for example, as conical friction elements. When the synchronization point is reached, the speeds of the gear elements to be synchronized are adjusted, which means that there is no change in the shifting path for a short time, so that it remains at least almost constant for a short period of time. If the switching path curve recorded during the adjustment of the switching element does not have such an at least approximately constant curve, then an error is detected when the switching element is adjusted. For example, if a shift rail, a shift fork or a shift finger breaks to operate the shift element when a gear is supposed to be engaged, no synchronization point is formed and an error is detected.

According to a further embodiment, it is provided that the target gearshift path profile for engaging a gear in an unsynchronized gearshift element of the gearbox has a region with an at least approximately constant profile when a tooth-on-tooth position occurs, which is taken into account in the fault detection . Becomes a If the unsynchronized switching element is actuated to perform a downshift, then the synchronization is known to take place by means of a motor and clutch control. The shifting elements of the transmission are brought to a connection speed of the gear to be shifted by partially closing the clutch and briefly increasing the engine speed. If an unsynchronized shifting element is actuated to carry out an upshift, a transmission brake is known to be controlled for synchronization in order to bring the shifting elements of the transmission to a connection speed of the gear to be shifted. When the gear is engaged, a so-called tooth-on-tooth position can occur on the unsynchronized switching element. If such a tooth-on-tooth position is recognized in the determined actual shift pattern, then a functional shift mechanism can be assumed.

However, since a gear can be engaged after the synchronization process without a tooth-on-tooth position, it cannot be automatically assumed that there is an error in the switching mechanism if there is no tooth-on-tooth position. Rather, it is provided here that this method of error detection is combined with a further method described here and an error in the switching mechanism is only considered to be recognized if an error was identified using both methods.

In certain operating situations of the vehicle, an adjustment of the transmission to a neutral position is provided. To implement the neutral position, a clutch arranged between a drive motor and the transmission is opened, whereby the drive motor is separated from the transmission. The neutral position is then set at least on one shift element of the transmission by disengaging the current transmission gear. By setting the neutral position in the transmission, the drive train remains disconnected even if the clutch arranged between the drive motor and the transmission is closed again after the neutral shift. Such an operating situation can be, for example, a vehicle standstill or a rolling phase of the vehicle. If a vehicle standstill is detected, the transmission is switched to neutral and then the clutch is closed again, so that the clutch release bearing can be protected during the vehicle standstill. Even during a rolling phase of the vehicle, during which the drive motor is separated from the drive wheels, the transmission is switched to neutral and the clutch is closed to protect the release bearing.

If, however, the neutral position of the transmission has been recognized, even though a gear is still engaged in the transmission, then when the clutch arranged between the drive motor and the transmission is closed, a frictional connection is restored in the drive train. When the vehicle is at a standstill, this leads to an unwanted start-up of the vehicle, which should be avoided for safety reasons. A rolling phase of the vehicle would also not be possible, since the drive train is operated in a push phase instead of the desired rolling phase when the gear is engaged after the clutch is closed. An overrun phase is understood to mean an operating situation of the vehicle in which the drive motor of the vehicle is dragged through the vehicle when the powertrain is closed in the drive train. The rolling phase is understood to mean an operating situation of the vehicle in which the internal combustion engine can be operated with as little consumption as possible and with low emissions while idling, while the vehicle is rolling with the drive train open.

A neutral position of the transmission can be incorrectly recognized, for example, if the neutral position is determined by means of a displacement sensor which is arranged on a shift actuator for actuating a shift element. If the shift mechanism has an error in the form of a break, the neutral position of the shift element is determined by means of the displacement sensor although the shift element has not been shifted into the neutral position and consequently a gear is still engaged in the transmission. It is therefore imperative to recognize that an engaged gear has actually been disengaged when the shift element is actuated.

According to a further refinement, it is therefore provided that the target shifting path for the design of a transmission gear in the case of a shift element of the transmission designed as a claw shift element has a range which is caused by the configuration of a tooth profile of a claw toothing of the shift element. Depending on the design of the toothing profile, for example the design of a hook or rolling of the claw toothing, there is a slight sticking of the claw toothing to one another when the gear is disengaged. The jamming of the claw gears and thus the delay when disengaging the gear are also dependent on a torque load still acting on the shift element when disengaging the gear. The greater the torque load still acting on the switching element, the more the claw teeth of the switching element remain attached to one another. This sticking can be recognized as a corresponding delay in the switching path curve when determining the switching path curve and can be used for monitoring the switching mechanism. If the ascertained actual gearshift path curve shows a delay due to the toothing profile when the gear is disengaged, it can be assumed that the gear mechanism is functional and the gear has been disengaged.

If the claw gear teeth of the claw shifting element are disengaged while there is no torque at all, then the delay when designing the transmission gear can be very small or the claw gear teeth can also be disengaged without delay due to drive train vibrations. Therefore, it can preferably be provided that if no delay in the selection of the transmission gear has been detected, this method of error detection is combined with a further method described here, and an error in the gearshift mechanism is only considered to be detected if an error was detected using both methods .

According to a further refinement, it is provided that a gradient of the target switching path profile is compared with a gradient of the determined actual switching path profile and an error in adjusting the switching element is recognized if the gradient of the determined actual switching path profile deviates from the gradient of the target switching path profile . If the switching mechanism is broken, the inertial mass of the switching mechanism and, under certain circumstances, friction of the switching mechanism are reduced when the switching mechanism is actuated. As a result, with the same activation of the adjusting device for adjusting the switching element, the same is actuated at a higher speed or the acceleration. If the gradient of the determined actual switching path curve deviates from the gradient of the target switching path curve by more than a predeterminable tolerance, then an error is detected when adjusting the switching element.

According to one embodiment, it can be provided that the target switching path profile has at least two areas characterizing the switching path profile and the detection of an error when adjusting the switching element occurs only when there is a deviation between the target switching path profile and the determined actual switching path profile on at least two of the there are ranges characteristic for the target shift path. Consequently, different detection methods for error detection can be taken into account, an error only being recognized if it has been recognized by several of the detection methods.

According to a further embodiment, it is provided that a tolerance range is provided around the target switching path profile and that an error when adjusting the switching element is only recognized when the deviation between the target switching path profile and the determined actual switching path profile lies outside the tolerance range. A tolerance range is to be understood as a permissible deviation from the target shift path within which the functionality of the switching mechanism is not endangered. A deviation from the target switching path within the tolerance range can arise, for example, due to a temperature influence or wear of the switching mechanism. If the recorded actual shift path lies outside the tolerance range, the shifting mechanism is no longer functional, which is recognized by a corresponding error.

The invention further relates to a control device which is designed to carry out the method according to the invention. The control device comprises means which are used to carry out the method according to the invention. These resources are hardware resources and software resources. The hardware means are data interfaces for exchanging data with the drive train assemblies involved in carrying out the method according to the invention. For this purpose, the control device is also connected to necessary sensors and, if necessary, also to other control devices, for example an engine control device, in order to record the data relevant to the decision or to forward control commands. The hardware means of the transmission control unit are also a processor for data processing and a memory for data storage. The software-side means are program modules for carrying out the method according to the invention.

The solution according to the invention can also be embodied as a computer program product which, when it runs on a processor of a control device, software-wise guides the processor to carry out the associated method steps according to the invention. In this context, the subject of the invention also includes a computer-readable medium on which a computer program product described above is stored and can be called up.

• 1 einen schematischen Aufbau eines automatisierten Gruppengetriebes;
• 2 eine schematische Darstellung eines Antriebsstrangs mit einem Steuergerät zur Durchführung des erfindungsgemäßen Verfahrens;
• 3 einen Schaltwegverlauf beim Betätigen eines synchronisierten Schaltelements des Getriebes und
• 4 einen Schaltwegverlauf beim Betätigen eines unsynchronisierten Schaltelements des Getriebes.

To clarify the invention, the description is accompanied by a drawing with exemplary embodiments. In these shows:

• 1 a schematic structure of an automated group transmission;
• 2nd a schematic representation of a drive train with a control unit for performing the method according to the invention;
• 3rd a shift path when actuating a synchronized switching element of the transmission and
• 4th a shift path when actuating an unsynchronized shift element of the transmission.

This in 1 Group transmission shown comprises a three-stage main transmission HG , one of the main gearbox HG upstream series group or split group VG as well as the main gear HG downstream area group BG . The main gear HG of the group transmission is designed here as a direct gear transmission in countershaft construction and has a main shaft W2 and two countershafts W3a and W3b on, with the first countershaft W3a is provided with a controllable transmission brake Br.

The main gear HG is with three translation levels G1 , G2 , G3 for a forward drive and a gear ratio R designed for a reverse trip in three stages. Idler gears of the gear ratios G1 , G2 and R are each rotatable on the main shaft W2 stored and switchable via assigned clutches. The assigned fixed wheels are non-rotatable on the countershafts W3a and W3b arranged.

The clutches of the gear ratios G3 and G2 as well as the clutches of the gear ratios G1 and R are each in a common circuit package S2 / 3rd or. S1 / R summarized. The main gear HG is designed to be unsynchronized, switchable.

The ballast group VG The group transmission is designed in two stages and also designed in countershaft construction, the two transmission stages K1 , K2 the primary group VG two switchable input constants of the main gear HG form. Due to a smaller translation difference between the two translation levels K1 , K2 is the primary group VG designed as a split group. The first-stage idler gear K1 is rotatable on the input shaft W1 stored via a controllable disconnect clutch TK with a drive motor designed for example as a combustion or electric motor AT THE communicates.

The second gear idler gear K2 is rotatable on the main shaft W2 stored. Fixed gears of both gear ratios K1 , K2 the primary group VG are each non-rotatable with the countershafts W3a and W3b of the main gear HG connected. The synchronized clutches of the upstream group VG are in a common circuit package SV summarized.

The main gear HG subordinate area group BG The group transmission is also designed in two stages, but in a planetary design with a simple planetary gear set. The sun gear PS is non-rotatable with the main shaft extended on the output side W2 of the main gear HG connected. The planet carrier PT is non-rotatable with the output shaft W4 of the group transmission coupled. The ring gear PH stands with a switch package SB with two synchronized clutches in connection through which the range group BG alternately by connecting the ring gear PH with a fixed housing part in a slow speed stage L and by connecting the ring gear PH with the planet carrier PT in a high-speed stage S is switchable. The area group BG is synchronously switchable.

A control of the clutches present in the group transmission for setting a desired gear ratio ( K1 , K2 , G3 , G2 , G1 , R , L , S ) is controlled or regulated via a control unit. The control unit can preferably be designed as a transmission control unit. The shift clutches are adjusted by means of a shift mechanism, not shown here, the shift mechanism being actuated by means of a shift actuator.

The method according to the invention for error detection can be used when adjusting a clutch of the group transmission. Here, an actual shift path curve is determined during the adjustment of a clutch of the group transmission and compared with a stored target shift path curve. If there is a discrepancy between the target shift path curve and the determined actual shift path curve, then a corresponding error is detected when adjusting the switching element. A break in the shift mechanism can be recognized as an error, for example a break in a shift fork, sliding blocks in the shift fork, a shift clutch or a shift finger. Because the clutches of the primary group VG and the area group BG are synchronized, while the clutches of the main transmission HG are not synchronized, is when comparing the determined actual shift path with the target shift path for the clutches of the upstream group VG and the area group BG a different target shift path course to take into account than for the clutches of the main transmission HG .

Out 2nd goes a schematic representation of a drive train 1 of a vehicle, which is a commercial vehicle, such as a truck. This drivetrain 1 has a drive motor, which has an intermediate separating clutch on its output side 3rd can be coupled to a drive side of an automated transmission. On the output side, the automated transmission is then connected to further output components, which are well known to the person skilled in the art, and to the vehicle wheels of the commercial vehicle.

The vehicle also includes a control system 2nd , in which several different control units via a data bus system 5 , for example via a CAN bus system. Among other things, are in the data bus system 5 a transmission control unit TCU and an engine control unit ECU are provided, of which the engine control unit ECU regulates the drive motor and the transmission control unit TCU regulates the automated transmission, and - possibly indirectly via a further control unit - also regulates the disconnect clutch 3rd makes. The transmission control unit TCU can communicate bidirectionally on the one hand with the transmission and on the other hand with the engine control unit ECU. Via the data bus system 5 the control units are supplied with the data relevant to them. The control units are able to record and process sensor signals and, depending on them, output control or data signals.

The TCU transmission control unit includes a processor 6 and storage means 7 for storing and retrieving parameters, signals and information as well as a computer program product 11 , which is designed in such a way that it can determine an error when adjusting a clutch of the automated transmission in the sense of the method described above. The target shift travel curves for the various clutches of the transmission are stored in the non-volatile memory in the TCU. The non-volatile memory can be designed, for example, as an EEPROM. The transmission control unit TCU also has at least one reception interface 8th which is designed to receive all relevant data from sensors and the engine control unit TCU. The TCU transmission control unit also has an evaluation unit 9 to process and evaluate the received data or the information of the received data, and a transmission interface 10th , which can be used to output corresponding signals for controlling drive train components.

The TCU transmission control unit controls the operation of the transmission using driving state data and driver request data. A shift strategy stored in the transmission control unit TCU in the form of a computer program determines respective shift reactions, in particular a gear change from a current actual gear to a target gear, or a temporary interruption in the traction in the drive train 1 .

The tax system 2nd also includes means for actuating the automated transmission and the disconnect clutch 3rd . These means include suitable switching valves via which an actuator system of the automated transmission or the disconnect clutch can be controlled. The means mentioned each comprise a data-transmitting connection 4th to the respective control unit. The data transfer connection 4th between the control units and the drive train components 1 can also be implemented, for example, by one or more electronic bus systems.

It is now provided in the present case that the transmission control unit TCU executes the method according to the invention while adjusting a clutch of the group transmission via the receiving interface 8th Receives sensor data from at least one position or displacement sensor arranged on the switching mechanism. The evaluation unit 9 uses the received sensor data or the information from the received sensor data to determine the actual shift path curve of the actuated clutch and compares the determined actual shift path curve with a stored target shift path curve. If there is a discrepancy between the target shift path curve and the determined actual shift path curve, then a corresponding error is detected when adjusting the switching element. The vehicle driver can be shown on a display that an error, for example a break in the switching mechanism, was detected when a switching element was adjusted.

The 3rd shows a target switching path 12 when changing the translation levels K1 , K2 the primary group VG of in 1 shown group transmission. At the beginning of the process, the gear ratio is in the group transmission K1 the primary group VG inserted. At a point in time t1, the synchronized clutch of the upstream group becomes VG actuated by actuating a switch actuator. This will make the translation level K1 designed. At time t2, the clutch reaches the so-called synchronizing point at which the synchronizing elements of the synchronized clutch come into contact with one another. The speeds of the gear elements to be synchronized are matched by means of the synchronizing elements of the clutch, which means that there is no change in the switching path for a short time, so that it remains at least almost constant for a short period of time. The time period during which the switching path remains constant or at least approximately constant can be, for example, 50 ms. At time t3, the speeds of the gear elements to be synchronized are matched to one another and the gear ratio K2 is inserted by further adjusting the clutch. The translation stage is at time t4 K2 the primary group VG inserted.

In the 3rd is next to the target switching path 12 also an actual shift travel curve determined during the adjustment of the clutch 13 shown. By means of a position or displacement sensor arranged on the shift actuator or the shift mechanism, it is detected that the gear ratio K1 designed and the translation level K2 was inserted between times t3 and t4. This determined actual shift travel curve 13 However, between the times t1 and t2 there is no at least almost constant switching path. From this it can be concluded that the clutch has not reached the synchronization point due to a broken shift mechanism and possibly the gear ratio K1 is still inserted. The determined actual switching path 13 is also outside of the target shift path 12 provided tolerance range 14 , which detects an error when adjusting the clutch.

When changing a gear ratio of the transmission from an actual gear ratio to a target gear ratio, an evaluation of the speeds occurring in the drive train can be used to check whether the actual gear ratio has been designed and whether the target gear ratio has actually been engaged after the gearshift process has ended. If the target gear ratio has been successfully inserted, the gear output speed will be different from the gear ratio originally set for the same gear input speed. Consequently, the result of the error detection according to the method according to the invention can be checked for plausibility by evaluating the speeds occurring in the drive train.

The 4th shows a target switching path 15 when changing the translation levels G2 , G3 of the main gear HG of in 1 shown group transmission. At the beginning of the process, the gear ratio is in the group transmission G2 of the main gearbox. At a time t1, the non-synchronized clutch of the main transmission HG actuated by actuating a switch actuator. This will make the translation level G2 designed. Between the times t1 and t2, the target switching path course 15 when designing the translation level G2 an area which is caused by the configuration of the tooth profile of the claw teeth of the clutch. This is how the translation level is laid out G2 delayed due to the design of a rear hook or rear roll of the claw teeth. At time t2, the gear ratio is designed and the clutch is in a neutral position N. Starting from the neutral position N, the clutch is used to engage the gear ratio G3 controlled. When the gear is engaged, a so-called tooth-on-tooth position can occur on the non-synchronized clutch, which is in accordance with the target shift path 4th is shown between times t3 and t4. If such a tooth-on-tooth position, even if only a short one, is recognized in the ascertained actual shifting course, then a functional shifting mechanism can be assumed. The translation stage is at time t4 G3 of the main gear HG inserted.

In the 4th is next to the target switching path 15 also an actual shift travel curve determined during the adjustment of the clutch 16 shown. The determined actual switching path 16 is within a range of the target shift path 15 provided tolerance range 17th , whereby a correct adjustment of the switching element and thus a functional switching mechanism is recognized.

Reference symbol list

1

Powertrain

2nd

Tax system

3rd

coupling

4th

connection

5

Data bus system

6

processor

7

Storage means

8th

Receiving interface

9

Evaluation unit

10th

Transmission interface

11

Computer program product

12

Target switching path

13

Actual switching path

14

Tolerance range

15

Target switching path

16

Actual switching path

17th

Tolerance range

AT THE

Drive motor

TK

Separating clutch

VG

Ballast group, split group

SV

Switching package ( VG ), Direct shift clutch

K1

(first) translation level ( VG )

K2

(second) translation stage ( VG )

HG

Main gearbox

G1

(first) translation level ( HG )

G2

(second) translation stage ( HG )

G3

(third) translation level ( HG )

R

Reverse translation stage ( HG )

S1 / R

Switching package ( HG )

S2 / 3

Switching package ( HG )

BG

Area group

SB

Switching package ( BG )

L

Slow speed ( BG )

S

High speed ( BG )

PH

Ring gear ( BG )

PS

Sun gear ( BG )

PT

Planet carrier ( BG )

W1

Input shaft

W2

Main shaft

W3a

Countershaft

W3b

Countershaft

W4

Output shaft

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011006560 A1 [0003]

Claims (11)

A method for error detection when adjusting a shift element in a transmission, comprising the following steps: - adjusting the switching element to carry out a switching process, - determining an actual switching path (13, 16) during the adjustment of the switching element, - Comparing the determined actual switching path (13, 16) with a target switching path (12, 15) and - Detection of an error when adjusting the switching element if there is a discrepancy between the target switching path (12, 15) and the determined actual switching path (13, 16). Procedure according to Claim 1 , characterized in that the actual switching path (13, 16) is determined at the start of the actuation of an adjusting device for adjusting the switching element and until a target position of the switching element is reached. Procedure according to Claim 1 or 2nd , characterized in that in the case of a transmission with differently designed shift elements, a target shift path curve (12, 15) is stored for each of these shift elements, which is compared with the determined actual shift path curve (13, 16) when the respective shift element is actuated. Method according to one of the preceding claims, characterized in that the desired shift path curve (12) for engaging a transmission gear in a synchronized shift element of the transmission during the adjustment of the speeds of the transmission elements to be synchronized has an area with an at least approximately constant curve which is considered for error detection. Method according to one of the preceding claims, characterized in that the desired shift path (15) for engaging a gear in an unsynchronized shift element of the gear has a region with an at least approximately constant profile when a tooth-on-tooth position occurs, which is taken into account for error detection. Method according to one of the preceding claims, characterized in that the target shift path (12, 15) for the design of a transmission gear in a shift element of the transmission designed as a claw shift element has an area which is due to the configuration of a toothing profile of a claw toothing of the shift element and which is taken into account for error detection. Method according to one of the preceding claims, characterized in that a gradient of the desired switching path curve (12, 15) is compared with a gradient of the determined actual switching path curve (13, 16) and an error in adjusting the switching element is detected when the gradient of the determined actual switching path (13, 16) deviates from the gradient of the target switching path (12, 15). Method according to one of the preceding claims, characterized in that the target switching path profile (12, 15) has at least two areas which characterize the switching path profile and the detection of an error when adjusting the switching element takes place only when there is a deviation between the target switching path profile (12 , 15) and the determined actual shift travel curve (13, 16) is present in at least two of the areas characteristic of the desired shift travel curve (12, 15). Method according to one of the preceding claims, characterized in that a tolerance range (14, 17) is provided around the target switching path (12, 15) and the detection of an error when adjusting the switching element takes place when the deviation between the target switching path (12, 15) and the determined actual switching path (13, 16) is outside the tolerance range (14, 17). Control unit (TCU) of a transmission, which is set up to a method for error detection when adjusting a switching element of a transmission according to one of the Claims 1 to 9 perform. Computer program product with program code means, which are stored on a computer-readable data carrier, for a method for error detection when switching a shift element of a transmission according to one of the Claims 1 to 9 perform when the computer program product on a computer or on a control unit (TCU) according to Claim 10 is performed.

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