WO2013164219A1

WO2013164219A1 - Lever actuator of a friction clutch and method for designing said lever actuator

Info

Publication number: WO2013164219A1
Application number: PCT/EP2013/058333
Authority: WO
Inventors: Markus Baehr; Martin Vornehm
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2012-05-02
Filing date: 2013-04-23
Publication date: 2013-11-07
Also published as: DE112013002292A5; KR102014571B1; KR20150006025A; DE102013207289A1; MX350505B; MX2014010287A

Abstract

The invention relates to a lever actuator and a method for designing the lever actuator, which provides an engagement force over an engagement path to a lever element of friction clutches pushed together having clutch characteristic curves, subject to tolerances, of a clutch torque that can be transmitted over the engagement path, said lever actuator comprising an engagement lever, which is axially moved by a spindle drive along a rolling path and which acts on the lever element and which is preloaded at a lever end facing away from the lever element, wherein a rocking curve of the engagement lever for a rolling device that is driven by the spindle drive along the rolling path and that rolls between a base plate of the lever actuator and the rocking curve is designed according to an engagement force necessary for transmitting a maximum clutch torque to be transmitted for all clutch characteristic curves occurring within the tolerance. A design that extends the possible rolling paths or requires lower spindle forces of the spindle drive is achieved in that the rocking curve occurs by means of a key characteristic curve reproduced by means of a variance of the clutch characteristic curves of the actually necessary engagement force over the engagement path.

Description

Lever actuator of a friction clutch and method for its interpretation

The invention relates to a lever actuator in a pressed-friction clutch and a method for its interpretation on friction clutches with different characteristics of the engagement force on the engagement.

Pressed friction clutches are used in particular in drive trains with a dual-clutch transmission with two partial drive trains, in which each partial drive train can be coupled by means of a friction clutch to an internal combustion engine. In order to prevent blocking of the drive train in an emergency, at least one friction clutch is pressed and formed self-opening. This means that in a de-energized state of the friction clutch actuating clutch actuator - here a lever actuator - the friction clutch automatically in an open state in which no torque is transmitted, changes, and thus transmitted in case of failure to high torque on both friction clutches on the dual clutch transmission become. A depressed friction clutch is open in the non-actuated state and transmits no torque and is closed by the lever actuator by axially displacing a lever element, for example a lever spring or a pressure pot, from the lever actuator along an engagement path. Here, the turn of the lever member axially directly or by a fulcrum effectively against a counter-pressure plate relocated, non-rotatably connected to the platen pressure plate comes into operative engagement with friction linings of a clutch disc, so that depending on the Einrückweg a predetermined moment is transmitted via the friction clutch. To set the torque, a corresponding engagement force must be expended on the engagement of the lever actuator, which is not constant depending on series variations of clutch characteristics of the transmittable torque of the friction clutch on the Einrückweg. Rather, the lever actuator must be designed so that it can set the required maximum clutch torque over the scattering range of the clutch characteristics via the engagement path to be provided.

A generic lever actuator and method for its operation are known, for example, from the documents DE 10 2004 009 832 A1, DE 10 2008 026 994 A1, DE 2009 010 136 A1, DE 10 2009 019 581 A1 and DE 10 2009 048 725 A1. A generic lever actuator includes, for example, a lever element of the friction clutch acting on the engagement lever, a base plate on which a motor driven by an electric motor spindle drive attached and a lever end of the engagement lever is received biased. Of the Spindle drive drives a with respect to the axis of rotation of the friction clutch radially to a displaceable roller device, which rolls between the base plate and the engagement lever. A preferably provided on the engaging lever Abrollprofil in the form of a rocking curve sets the depending on the spindle force of the spindle drive and the bias of the engagement lever on the roller path of the roller device and thus the effective along the dependent of this adjusting Einrückweg engagement. The interpretation of the lever actuator is carried out on a clutch characteristic in which the maximum available spindle force is set at the lowest engagement paths for the transmission of the maximum transmissible clutch torque. This results in this roller path for the remaining friction clutches with so-called longer curves, so at larger engagement the maximum transmissible clutch torque adjusting engagement force, lower spindle forces. Here, the roller path is designed for the longest clutch characteristic. It has been found here that with strong scattering of the coupling characteristics, a ratio to be provided by the rocking curve in the shortest characteristic is very high, so that in the case of large roller paths, the friction clutch can be overloaded. For long curves, however, the required roller path may not be sufficient to adjust the maximum transmittable torque.

An object of the invention is therefore to design a lever actuator according to that it can be used for a maximum number of pressed-friction clutches with a series dispersion whose clutch characteristics. Furthermore, an improved method for its interpretation should be proposed. Another aspect of the task is to reduce the spindle power of the spindle drive, for example, to be able to use smaller electric motors.

One aspect of the object is achieved by a method for designing a frictionally engaged by a clutch engagement on a lever element zugedrückter friction clutches with toleranced clutch characteristics of the engageable clutch torque on the Einrückweg lever actuator with one of a spindle drive along a roller path axially displaced, the lever element acting on one Lever element facing away from the lever end biased engagement lever, wherein a rocking cam of the engagement lever for a driven by the spindle drive along the roller path, rolling off between a base plate of the lever actuator and the rocking roller device depending on a for transmitting a maximum to be transmitted clutch torque for all occurring within the tolerance clutch characteristics necessary Einrückkraft is designed, solved, with a design of the rocking curve on the basis of a variance of the clutch characteristics of the Actually necessary engagement force on the Einrückweg simulated corner curve is done. The design of the lever actuator by means of such a corner characteristic no longer follows a real clutch characteristic. Rather, such a corner characteristic is synthetically adapted to the required working range of the lever actuator with different coupling characteristics. Here, advantageously, the corner characteristic of an engagement force along a clutch characteristic with the smallest Einrückweg to Einrückkraft at maximum transferable clutch torque following part characteristic and then following the Einrückweg at a given engaging force over a course of the transmission of the maximum clutch torque necessary engagement force tolerance width of the clutch characteristics associated engagement Part characteristic formed. In detail, the lever actuator according to the invention is advantageously only so controlled that the corner map is not left, so as to keep the mechanical loads low. In such a control method, the actually required actuating travel is identified and used as a limitation in a control device. The identification can be done while driving by adaptations, or in the production and the result can be stored.

Another aspect of the object is by a lever actuator with a biased at one end to a base plate, a lever element of a friction clutch at the other end of the lever axially acting actuating lever and, a lever point of the actuating lever forming, displaced by a spindle drive radially along a roller path roller unit on solved the base plate and a rocking cam of the actuating lever rolling roles, wherein over the roller path a tangential angle between roller and rocking curve at a predetermined waypoint jumps. At this waypoint, a slope of the seesaw curve from a mean roller path to a given waypoint is preferably less than a slope from the waypoint to the maximum rollerpath.

Furthermore, a method of operating such a lever actuator may be advantageous in order to actuate a friction clutch. Here, a maximum required actuation path is determined for complete actuation of the friction clutch and prevents actuation of larger actuation paths of a control unit. In this way, overloading of the lever actuator can be prevented, in particular in the case of short characteristic curves of a friction clutch within a given production spread. The maximum actuation travel can be determined, for example, during an adaptation and / or startup, for example by determining the actuation forces via the actuation path and by assigning and storing a maximum actuation travel for a given actuation force. The invention will be explained in more detail with reference to the embodiments shown in Figures 1 to 6. Showing:

FIG. 1 is an illustration of a corner characteristic curve tuned to a working region of a lever actuator;

FIG. 2 shows a characteristic diagram of the control unit via the corner characteristic and clutch characteristics

Hebelaktors,

FIG. 3 shows a schematically illustrated engagement lever of a lever actuator with a rocking curve designed on the basis of the corner characteristic of FIGS. 1 and 2;

4 shows a diagram of the rocking curve in a Cartesian coordinate system, FIG. 5 shows a diagram of the tangent angle between a roller of the roller device and the rocking curve along a longitudinal axis

and

Figure 6 is a diagram of the tangent angle with reduced spindle force.

The diagram 1 shows the engagement force against the Einrückweg a lever actuator and the crowd 2 of belonging to a depressed friction clutch clutch characteristics 2a, 2b, .... 2n, which due to their series dispersion, for example, scattering in the geometric dimensions, friction coefficients of the friction linings and the like build up a corresponding clutch torque with different return paths, whereby the maximum transmittable clutch torque is indicated by the symbols □. In contrast to interpretations of the rocking curve of the lever actuator shown in more detail in Figure 3 for a given bias this against the base plate and predetermined maximum spindle force on the characteristic 2a with to set their maximum transmittable clutch torque at minimum Einrückweg, the rocking curve is designed using the synthetically determined corner line 3. This follows in a first part of characteristic curve 4 of the so-called shortest clutch characteristic 2a up to their maximum transmittable or intended clutch torque M (2a) and follows in the second part of the characteristic curve 5 maximum transferable moments of the other curves 2b, .... 2n. As a result, the real working area of the lever actuator is included.

FIG. 2 shows the diagram 1 a provided with the family 6 of the lever characteristics 6 a, 6 b,. The lever characteristic curves 6a, indicate the engaging force available from the applied spindle force via the engagement path in the case of roller systems rising from bottom to top. In this case, in order to provide an engagement force that varies for a given clutch torque and as a result of the engagement force varying as a function of the clutch characteristic line 2a, 2b,... clear Einrückweg required, which is done by appropriate adjustment of a roller path. Depending on the translation of the engagement lever at this position of the engagement path, a corresponding spindle force of the spindle drive is necessary to set the clutch torque. As a result, the lever curves 6a, 6b,... 6n, which are shown by way of example, intersect the clutch characteristics 2a, 2b, 2n at the corresponding clutch torque. Due to the design of the lever characteristic curves 6a, 6b, .... 6n on the basis of the corner characteristic 3, a larger range of the engagement path is available for large engagement paths as a comparison with dashed lines shown lever characteristics 6η ', 6η-1', 6n-2 ', which are designed on the basis of the shortest clutch characteristic 2a, shows. With the designed according to the corner characteristic rocking curve of the lever actuator can thus a higher scattering of the clutch characteristics 2a, 2b, ... 2n are covered. Alternatively, in a design of the rocking curve according to the corner characteristic 3 in the limits of the lever characteristic 6n 'lower spindle forces are provided so that the necessary to provide the spindle forces electric motor can be dimensioned smaller and thus can be incorporated into smaller spaces.

Figure 3 shows a schematic representation of the engagement lever 7 from the side. At the one end of the lever 8, the engagement lever 7 acts on the rotation axis d of the friction clutch, a pressure pot or a lever spring this. At the other end of the lever 9 of the engaging lever 7 is received by means of the only indicated energy storage 10 against the base plate 1 1 prestressed. On the one hand by means of only indicated rollers 12 on the base plate 1 1 and on the other hand by means of the roller 13 with the inclusion of the tangential α on the Wippkurve 14 rolling roller device 15 is displaced along the roller path s (r) by a spindle drive, not shown, radially to the rotation axis d and forms Thus, a lever point for the engagement lever 7. About the traversed roller path s (r) is formed depending on the shape of the rocking cam 14 of the axial engagement s (e) of the lever actuator. The rocking curve 14 is designed on the basis of the corner characteristic 3 of Figures 1 and 2 and has over the original, based on the shortest clutch characteristic, dashed illustrated rocking curve 14 'from the waypoint s (g) to large roller paths s (r) towards an increased pitch on. It is thereby achieved that in this Rollenwegbereich longer engagement paths s (e) can be achieved.

FIG. 4 shows the projection of the rocking curves 14, 14 'of FIG. 3 into the Cartesian coordinate system 16 with the coordinate x corresponding to a longitudinal path and a coordinate y corresponding to a stroke. From this the actual scale change of the Slope of the rocking curve 14 with respect to the rocking curve 14 'at the waypoint s (g) crossing roller paths clearly.

FIG. 5 shows the diagram 17 with the tangential angle α projected along the roller path s (r) of FIG. 3, projected onto the linear coordinate x, between the roller 13 and the rocking curves 14, 14 '. From this it is clear that, compared with the continuous development of the tangential angle α of the rocking curve 14 ', the tangential angle α of the rocking curve 14 in the region of the waypoint s (g), which essentially corresponds to the inflection point of the corner characteristic 3 between the subcharacteristics 4, 5 (FIG ), has a discontinuity.

FIG. 6 shows a special case of the diagram 17 of FIG. 5, in which the seesaw curve 14 is designed only for a larger engagement travel s (e) (FIG. 3). In the diagram 18 of FIG. 6, the rocking curve 14a is optimized in addition to the rocking curve 14 'in addition to low actuator forces, so that overall the tangential angles α at the corresponding taxiway positions are smaller than in the rocking curve 14'.

LIST OF REFERENCE NUMBERS

1 diagram

1 a diagram

crowd

a clutch characteristic

b Coupling characteristic

n clutch characteristic

3 corner characteristic

Part characteristic

5 part characteristic

6 flock

6a lever characteristic

6b lever characteristic

6n lever characteristic

6n 'lever characteristic

6n-1 lever characteristic

6n-2 lever characteristic

7 engagement lever

8 lever end

9 lever end

10 energy storage

1 1 base plate

12 roll

13 roll

14 rocking curve

14 'seesaw curve

14a seesaw curve

15 roller device

16 coordinate system

17 diagram

18 diagram

d rotation axis

M (2a) Clutch torque engagement path

waypoint

roller path

coordinate

tangential

Claims

claims

1 . A method of designing a frictional engagement with an engagement force (s (e)) on a lever member with toleranced clutch characteristics (2a, 2b, 2n) of a transmittable clutch torque over the engagement travel (s (e)) with one of a spindle drive a rocking path (s (r)) axially displaced, the lever element acted upon, on a leverage element facing away from the lever end (9) biased engagement lever (7), wherein a rocking curve (14, 14a) of the engagement lever (7) for one of the spindle drive along the Roller path (s (r)) driven between a base plate (1 1) of the lever actuator and the rocking cam (14, 14a) rolling roller device (15) depending on a for transmitting a maximum to be transmitted clutch torque for all occurring within the tolerance clutch characteristics ( 2, 2a, 2n) necessary engaging force is designed, characterized in that a design of the rocking curve (14 , 14a) on the basis of a over a variance of the coupling characteristics (2, 2a, 2n) of the actual necessary engagement force on the engagement path (s (e)) simulated corner line (3).

2. The method according to claim 1, characterized in that the corner characteristic (3) of a engagement force along a clutch characteristic (2a) with the smallest Einrückweg (s (e)) to the engagement force at maximum transferable clutch torque (M (2a)) following part characteristic (4) and a sub-characteristic curve (5) following a reaction path at a given engagement force over a course of the engagement force required for transmitting the maximum clutch torque of a tolerance width of the clutch characteristics (2b, 2n) is formed.

3. Lever actuator with a at one end of the lever (9) relative to a base plate (1 1) biased, a lever element of a friction clutch at the other end of the lever (8) axially acting engagement lever (7) and one, a fulcrum of the engagement lever (7) forming, of a roller device (15) displaced radially along a roller path (s (r)) with rollers (12, 13) rolling on the base plate (11) and a rocking cam (14, 14a) of the engaging lever (7), according to the method according to claim 1 or 2 designed Wippkurve (14, 14a).

4. lever actuator according to claim 3, characterized in that on the roller path (s (r)) a tangential angle (a) between the roller (13) and rocking curve (14, 14a) at a predetermined waypoint (s (g)) increases abruptly.

5. lever actuator according to claim 4, characterized in that a slope of the rocking curve (14, 14a) of a middle roller path (s (r)) zero to the waypoint (s (g)) is less than a slope of the waypoint (s (g)) to the maximum roller path.

6. A method for operating a lever actuator for actuating a friction clutch according to claims 1 to 5, characterized in that a maximum required actuating travel (s (g)) determined for complete actuation of the friction clutch and an actuation of larger actuation paths is prevented by a control unit.