DE102015218884A1 - Method for determining at least one parameter of a separating clutch - Google Patents

Abstract

The invention relates to a method for determining at least one parameter of a separating clutch, wherein a torque characteristic of the separating clutch is determined, which describes a dependence of a transferable via the separating clutch torque (T _Cl ) of a clutch travel, which is set via a Stellaktuator. In order to be able to determine the at least one parameter as accurately as possible in the course of the use of the separating clutch, the torque characteristic curve based on a force-clutch travel characteristic of an isolating clutch (F _B ) of the actuating actuator and a force-clutch travel characteristic of a restoring force (F _m ), which is applied to the separating clutch in the direction of a closed state and which was determined from the characteristic of the actuating force (F _B ).

Description

The invention relates to a method for determining at least one parameter of a disconnect clutch, wherein a torque characteristic of the disconnect clutch is determined, which describes a dependence of a transferable via the disconnect clutch torque of a clutch travel, and wherein the clutch travel is adjusted via a Stellaktuator. Furthermore, the invention relates to a control device, a computer program product and a data carrier having this.

Starting elements in motor vehicle drive trains are often designed as disconnect couplings and are then available as dry or wet-running friction clutches. When the separating clutch is combined with a downstream, automated or even automatic motor vehicle transmission, the respective separating clutch is then also usually carried out automatically, i. An opening and closing of the separating clutch is carried out automatically via an associated control. For such a control is an accurate knowledge of certain parameters of the clutch necessary, in particular a torque curve to control the operation of the clutch as precisely as possible and thus make it possible to start and switching operations as comfortable as possible.

From the DE 10 2008 032 475 A1 goes out a method for determining a characteristic of a separating clutch, wherein in the method, a torque characteristic of the separating clutch is determined in order to calibrate the separating clutch. In this case, the torque characteristic describes a dependency of a torque that can be transmitted via the separating clutch from a clutch travel that is set via a setting actuator. For the determination of the torque characteristic is thereby assumed an empirically determined characteristic, in which case the actual dependence of the transmitted clutch torque is determined by a travel of the actuating actuator. For this purpose, several different clutch paths are successively set by the adjusting actuator and measured each transmitted clutch torque, which is followed by a corresponding correction of the empirically determined characteristic curve is made to a suitable torque curve. All this is done on a test bench.

Starting from the above-described prior art, it is now the object of the present invention to determine at least one parameter of a separating clutch, wherein this determination should be possible as accurately as possible in the course of the use of the separating clutch. The determination of the at least one parameter should therefore be as accurate as possible in the course of the installed state and the use of the separating clutch.

This object is achieved on the basis of the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims give each advantageous embodiments of the invention. From a device-technical point of view, a solution of the object by a control device according to claim 9 or 10. Furthermore, a computer program product, as well as a data carrier having this subject matter of claims 11 and 12.

According to the invention, in a method for determining at least one parameter of a disconnect clutch, a torque characteristic of the disconnect clutch is determined, which describes a dependency of a torque transferable via the disconnect clutch from a clutch travel. The clutch travel of the clutch is adjusted via a Stellaktuator.

In the context of the method according to the invention thus at least one parameter of the separating clutch is determined, which may be the torque curve itself or one or more further characteristics of the separating clutch. The torque characteristic is the transferable via the clutch torque as a function of the clutch travel again, with the "clutch" a respective set via the Stellaktuator distance between Reibpartnern the disconnect clutch is meant, which are assigned to each other and when closing the clutch the connection between coupling halves make the separating clutch.

The separating clutch is within the meaning of the invention in particular as over the Stellaktuator automated or automatically actuated clutch and is preferably designed as a friction clutch and in this case as a wet or dry running friction clutch. In concrete terms, the separating clutch may be a single-disk friction clutch or a friction clutch having a plurality of friction partner pairs.

The invention now includes the technical teaching that the torque characteristic curve is calculated based on a force-clutch travel characteristic of an operating force of the actuating actuator resulting from the disconnect clutch and a force-clutch travel characteristic of a restoring force with which the disconnect clutch is acted upon in a closed state and that has been determined from the characteristic curve of the actuating force. In other words, the determination of the torque characteristic is based on the characteristics of a resulting Actuating force of the adjusting actuator and a restoring force, wherein the restoring force is the force with which the separating clutch is acted upon in the direction of a closed state. In addition, the characteristic of the restoring force was determined from the characteristic of the actuating force.

Such a determination of at least one parameter has the advantage that a determination of the torque characteristic of the separating clutch is carried out based on force curves in the region of the separating clutch and thus based on mechanical conditions, allowing an accurate determination of the torque characteristic. At the same time this determination can be realized in the installed state and in the course of the use of the separating clutch.

In case of DE 10 2008 032 475 A1 However, a determination of the torque characteristic is performed in the context of a test bench operation, so it is no determination in the course of the use of the separating clutch possible.

In the context of the invention, the force-clutch travel characteristics of the actuating force and the restoring force in each case represent the dependence of the respective force on the clutch travel, i. the actuating force characteristic shows the course of the resulting actuating force over the clutch travel, while the characteristic curve of the restoring force describes the course of the restoring force over the clutch travel.

For the purposes of the invention, the "resulting actuating force" is understood to mean the actuating force of the actuating actuator which is actually operative in the region of the separating clutch. Depending on the connection of the adjusting actuator to the separating coupling, appropriate leverage ratios must be taken into account. In addition, in this case also a lining spring force of the clutch lining of the friction partners of the separating clutch must be included, i. a spring action of the clutch lining, with which the friction partners of the separating clutch are pressed apart.

The "restoring force" is to be understood as a force component which acts on the separating clutch in the closing direction and is applied by a component of the separating clutch, preferably a diaphragm spring.

According to an embodiment of the invention, the characteristic of the restoring force has been obtained by equating a portion of this characteristic over a range of the clutch travel to the associated range of the characteristic of the resultant operating force, whereas at least one adjacent portion of the characteristic of the restoring force is obtained from the equalized portion was determined by a mathematical approximation. For the determination of the characteristic curve of the restoring force, this is thus equated to the course of the characteristic curve of the resulting actuating force associated with this coupling travel range in a specific range of the clutch travel, so that in the following the course of the characteristic of the restoring force in this region of the clutch travel is known. One or more sections of the characteristic line of the restoring force connected thereto are then determined by approximation. This makes it possible to determine the characteristic of the restoring force in a simple yet reliable manner.

In a further development of the aforementioned embodiment, the characteristic of the restoring force of the characteristic curve of the resulting operating force in a range of the clutch travel between a contact point of the separating clutch and an opening point of the separating clutch has been equated. Due to the balance of forces in the area of the separating clutch, the situation arises in this area that both courses of force must be congruent. In this respect, an equalization of the known characteristic of the resulting operating force with the characteristic of the restoring force can be performed here.

According to an alternative or additional development of the embodiment described above, the approximation was carried out by means of a polynomial. In this way, a mathematical approximation to the actual course of the characteristic can be realized in addition to the section obtained by equating. An approximation to the actual course can be carried out with a polynomial of first or even higher, for example, third order. Parameters of the polynomial can be determined, for example, by means of the RLS method (Recursive Least Square)

According to a further embodiment, which is an alternative or in addition to the aforementioned embodiment or its developments, a force-clutch travel characteristic of a contact force is determined from the difference of the characteristics of the resulting operating force and the restoring force, from which in turn the torque characteristic is determined. Thus, according to the formula F, the contact pressure is preferably _An = F _m - determined F _B where F _to, the clamping force, F _m, and the restoring force F _B is the resulting operating force. The contact force is then again used to determine the transmitted torque according to the equation T _Cl = F _An · zμr, where T _{Cl is} the torque, r the friction radius, z is the number of friction surfaces and μ is the friction coefficient.

In a further development of the invention, the characteristic curve of the resulting actuating force was calculated from a disengaging force of the adjusting actuator, which was determined directly by detection on the adjusting actuator. In this case, therefore, a disengagement force is measured on the adjusting actuator and then, if necessary taking into account existing gear ratios or incorporation of an effective pad spring force, determines the resulting actuating force. This development can then be realized if a direct detection or determination of the disengagement force is possible in the area of the adjusting actuator.

As an alternative to the development of the invention described above, the profile of the resulting actuating force was determined from a disengaging force of the actuating actuator, which was calculated on the basis of parameters of the actuating actuator. Thus, parameters of the adjusting actuator are used to determine its disengaging force and, based thereon, in turn, to close the operating force resulting from the separating clutch. Thus, in the case of a pneumatic actuating actuator, the disengagement force can be calculated from the gas equation by keeping a mass flow constant as far as possible when controlling the actuating actuator. Likewise, in the case of an electromechanical actuating actuator, the disengaging force can be derived from the current measurement.

It is a further embodiment of the invention that the torque characteristic curve is compared with a further torque characteristic that has been independently determined. Thus, this independently determined torque curve may have been determined based on a torque of an engine of the motor vehicle, which corresponds to the torque transmitted by the separating clutch with slipping clutch and substantially constant speed. By adjusting the two torque characteristics can then be concluded as a further characteristic of the separating clutch to a respective coefficient of friction of the friction partners of the separating clutch. In this respect, a wear detection of the separating clutch, and possibly a corresponding adaptation thereto can be realized thereby.

The invention also relates to a control device for a separating clutch, by which the procedural steps described in advance are realized. Thus, this control unit is designed to determine at least one parameter of the separating clutch, wherein the control unit for this device, in particular a processor of the control unit, has over which a torque characteristic of the separating clutch can be determined, the dependence of a transferable via the separating clutch torque of describes a coupling path. The control unit also has an interface for the connection with a Stellaktuator, via which the clutch travel of the clutch can be adjusted. The torque characteristic may be calculated by the device based on histories of a resultant actuating force of the actuating actuator and a restoring force which urges the separating clutch toward a closed state and which can be determined from the actuating force. The invention also relates to a computer program product of an aforementioned control device, by which the routine for calculating the torque characteristic of the separating clutch is implemented by corresponding stored in a software control commands. Furthermore, the invention relates to a data carrier having an aforementioned computer program product.

The invention is not limited to the specified combination of the independent or dependent claims. It also results in ways to combine individual features, even if they emerge from the claims, the following description of a preferred embodiment of the invention or directly from the drawings. The reference of the claims to the drawings by use of reference numerals is not intended to limit the scope of the claims.

An advantageous embodiment of the invention, which will be explained below, is shown in the drawings. It shows:

1 a schematic view of a portion of a motor vehicle drive train with a separating clutch, wherein at least one parameter can be determined in the manner according to the invention;

2 a flowchart of a method according to the invention for determining the at least one characteristic according to a preferred embodiment of the invention;

3 a schematic representation of power ratios in the release clutch 1 ; and

4 a diagram with different force characteristics of the separating clutch 1 , applied over the clutch path.

Out 1 is a schematic view of a portion of a motor vehicle drive train out, which is preferably the drive train of a commercial vehicle, such as a truck. In principle, the motor vehicle drive train could 1 but also be part of another motor vehicle, such as a car.

As in 1 can be seen, the motor vehicle drive train comprises a prime mover 1 , which is present in particular as an internal combustion engine and via an intermediate separating clutch 2 with a downstream motor vehicle transmission 3 is coupled. On the motor vehicle transmission 3 then follow other - not shown here - components of the motor vehicle powertrain. The separating clutch 2 is in the present case designed as a single-disk friction clutch, which via an associated Stellaktuator 4 can be disengaged to the connection between the prime mover 1 and the motor vehicle transmission 3 for starting operations of the motor vehicle or switching operations in the motor vehicle transmission 3 to separate. The actuating actuator 4 is doing via a control unit 5 the separating clutch 2 regulated, the clutch 2 is available as an automated clutch.

In the course of operation of the motor vehicle can now characteristics of the separating clutch 2 which takes place in the context of a method according to the invention, whose flowchart in 2 is shown and runs according to a preferred embodiment of the invention. As in 2 can be seen, it is in a first step S1 first, the course of a disengaging force F _{P of} the adjusting actuator 4 as a function of a clutch travel s of the separating clutch 2 determined, it being the clutch path s, as in 1 can be seen, a distance between friction partners 6 and 7 the separating clutch 2 is. The release force F _P is the force which is directly at Stellaktuator 4 is applied and over an intermediate lever 8th in a pushing apart of the friction partners 6 and 7 is implemented, like out 3 it can be seen which force relationships in the area of the separating clutch 2 illustrated.

The release force F _P can in the context of the method according to the invention either directly on the Stellaktuator 4 measured or it is calculated. Thus, in the context of the invention, it is conceivable, in the case of a pneumatic adjusting actuator, to calculate the disengaging force F _P from the gas equation by performing an actuation at virtually constant mass flows of an operating medium. Likewise, in the case of an electromechanical Stellaktuators 4 a calculation of the disengagement force F _P can be realized on the basis of the actuating current.

As in 2 It can be seen following the step S1, a step S2, in which a part of the clutch resulting actuating force F _B is determined, wherein it is ultimately in the direction of an open state of the separating clutch 2 acting total force acts. Thus, this operating force F _{B is} made up of the release force F _P , taking into account the lever ratio of the lever 8th and a pad spring force F _b together. The pad spring force F _b is the force which passes through the clutch lining of the friction partner 6 and 7 in the direction of an open state of the separating clutch 2 is caused.

A characteristic 9 the resulting operating force F _B is also in 4 represented in which various force characteristics are recorded on the clutch path s. The zero crossing of the actuating force F _B defines a Zupunkt CP of the separating clutch 2 , where the characteristic 9 the actuating force F _B in the following then to determine a characteristic 10 a restoring force F _m is used, which by a the disconnect clutch 2 in a closed state kraftbeaufschlagende - not shown here - diaphragm spring is applied. That's how it turns out 2 can be seen, in a step S3 initially determined a portion of the characteristic of the restoring force F _m over a range of the clutch travel s. This range is the clutch travel s between a contact point TP of the separating clutch 2 and an opening point OP of the separating clutch 2 because in this area the operating force F _m must correspond to the resulting operating force F _B.

Based on this, then in step S4 of the in 2 method shown, the remaining course of the restoring force F _{m determined} by mathematical approximation by an approximation using a polynomial is performed. In 4 is the actual characteristic 10 the restoring force F _m over the clutch travel s shown, as well as characteristics 11 and 12 the restoring force F _m , which have been calculated on the one hand by approximation of a first order polynomial or by approximation of a second order polynomial. As can be seen, this can be in the relevant area between closing point CP and opening point OP of the separating clutch 2 a sufficient approximation can be realized.

From the restoring force F _m and the resulting confirmation force F _B is then in the process in a step S5, the contact pressure F _on the clutch 2 according to the formula F _to F = _m - F _B calculated. The characteristic 13 the contact pressure F _An is also in 4 shown. With the help of the known characteristic 13 the contact pressure F _An is then in step S6 by the separating clutch 2 transmitted torque T _Cl calculated according to the formula T _Cl = F _An · 2μr, so that ultimately the torque characteristic of the clutch 2 is obtained, which describes the transmittable torque T _Cl over the clutch path s.

As in 2 can be seen, is parallel to the steps S1 to S6 in step S7 nor an independent determination of another characteristic a torque T _{Cl * of} the separating clutch 2 performed by in a slip operation of the separating clutch 2 at substantially constant speeds of the prime mover 1 a torque T _{mot of} the prime mover 1 is detected in a step S8, which in this case by the separating clutch 2 transmitted torque T _{Cl *} corresponds. This characteristic curve of the torque T _{C1 *} is adjusted in a step S9 with the determined curve of the torque T _C1 from step S6 to a state of wear of the separating clutch 2 to observe and actuation of the separating clutch 2 adapted accordingly.

The method steps S1 to S10 are performed by a processor of the control unit 5 performed, which is supplied via appropriate interfaces with the relevant information. This is the control unit 5 integrated into a data bus of the motor vehicle, via which it inter alia the engine torque T _{mot of} the prime mover 1 can be communicated. The instructions of the processor for carrying out the individual method steps is as a computer program product on a data carrier of the control unit 5 deposited.

By means of the method according to the invention, a determination of at least one parameter of a separating clutch in the course of their use can be realized with high accuracy.

LIST OF REFERENCE NUMBERS

1

prime mover

2

separating clutch

3

Motor vehicle transmission

4

positioning actuator

5

control unit

6

friction partners

7

friction partners

8th

lever

9

Characteristic F _B

10

Characteristic F _m

11

Characteristic F _m (1st order polynomial)

12

Characteristic F _m (3rd order polynomial)

13

Characteristic F _An

F _P

disengaging

F _b

Covering spring force

F _B

operating force

F _m

Restoring force

F _An

contact force

T _Cl

Torque clutch

T _{Cl *}

Torque clutch

T _mot

engine torque

CP

to-point

TP

Feeding point

operating room

opening point

s

clutch travel

H

lever arm

S1 to S10

individual steps

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• DE 102008032475 A1 [0003, 0011]

Claims (12)

Method for determining at least one parameter of a separating clutch ( 2 ), wherein a torque characteristic of the separating clutch ( 2 ), which determines a dependence of one via the separating clutch ( 2 ) transmissible torque (T _Cl ) of a clutch path (s) describes, and wherein the clutch travel (s) via a Stellaktuator ( 4 ) is set, characterized in that the torque characteristic based on a force-clutch travel characteristic ( 9 ) one side of the separating clutch ( 2 ) resulting actuating force (F _B ) of the Stellaktuators ( 4 ) and a force-clutch travel characteristic ( 10 ; 11 ; 12 ) of a restoring force (F _m ) is calculated with which the separating clutch ( 2 ) is acted upon in the direction of a closed state and from the characteristic ( 9 ) of the actuating force (F _B ) has been determined. Method according to Claim 1, characterized in that the characteristic curve ( 11 ; 12 ) of the restoring force (F _m ) was determined by a section of this characteristic curve ( 11 ; 12 ) over a range of the clutch travel (s) the associated region of the characteristic ( 9 ) has been set equal to the resulting actuating force (F _B ), whereas at least one adjacent section of the characteristic curve (F _B ) 11 ; 12 ) of the restoring force (F _m ) was determined from the equation obtained by equations by a mathematical approximation. Method according to Claim 2, characterized in that the characteristic curve ( 11 ; 12 ) of the restoring force (F _m ) of the characteristic ( 9 ) of the resulting actuating force (F _B ) in a region of the clutch path (s) between a contact point (TP) of the separating clutch ( 2 ) and an opening point (OP) of the separating clutch ( 2 ) has been equated. A method according to claim 2, characterized in that the approximation has been carried out by means of a polynomial. Method according to Claim 1, characterized in that the difference between the characteristic curves ( 9 ; 10 ; 11 ; 12 ) of the resulting actuating force (F _B ) and the restoring force (F _m ) a force-clutch travel characteristic ( 13 ) of a contact force (F _An ) is determined, from which in turn the torque characteristic is determined. Method according to Claim 1, characterized in that the characteristic curve ( 9 ) of the resulting actuating force (F _B ) from a disengagement force (F _P ) of the Stellaktuators ( 4 ) calculated directly by detection at Stellaktuator ( 4 ) was determined. Method according to Claim 1, characterized in that the characteristic curve ( 9 ) of the resulting actuating force (F _B ) from a disengagement force (F _P ) of the Stellaktuators ( 4 ) determined by parameters of the actuator ( 4 ) was calculated. A method according to claim 1, characterized in that the torque characteristic is matched with a further torque characteristic, which has been independently determined. Control unit ( 5 ) for a separating clutch ( 2 ), designed to at least one characteristic of the separating clutch ( 2 ), wherein a device is provided, via which a torque characteristic of the separating clutch ( 2 ), which determines a dependency of one via the separating clutch ( 2 ) transmissible torque (T _Cl ) from a clutch path (s), and wherein an interface for the connection with a Stellaktuator ( 4 ) is configured, via which the clutch path (s) of the separating clutch ( 2 ), and wherein the torque characteristic is determined by the device based on a force-clutch travel characteristic ( 9 ) of a resultant actuating force (F _B ) of the actuating actuator ( 4 ) and a force-clutch travel characteristic ( 10 ; 11 ; 12 ) of a restoring force (F _m ) can be calculated, which the separating clutch ( 2 ) in the direction of a closed state and from the characteristic curve ( 9 ) of the actuating force (F _B ) can be determined. Control unit ( 5 ) according to claim 9, by which a method according to one or more of claims 2 to 8 is feasible. Computer program product of a control device ( 5 ) according to claim 9 or 10, by which a method according to one or more of claims 1 to 8 is feasible, wherein a routine for calculating the torque characteristic of the separating clutch ( 2 ) is implemented by appropriate stored in a software control commands.  Data carrier with a computer program product according to claim 11.

Images