DE102014204338A1 - Clutch actuation system for opening and / or closing a friction clutch and method for coupling a drive shaft of an automotive engine with a transmission input shaft of a motor vehicle transmission - Google Patents

Abstract

A clutch actuation system is provided for opening and / or closing a friction clutch with a ramp system for axially displacing a pressure plate of a friction clutch, the ramp system having an input ramp and an output ramp that can be rotated relative to the input ramp to change an axial extension of the ramp system, a pilot clutch for triggering a Rotation of the input ramp relative to the output ramp as a result of a differential speed between a torque introduction element, in particular the drive shaft of a motor vehicle engine, and a torque output element, in particular a transmission input shaft of a motor vehicle transmission, and a trigger unit for actuating the pilot clutch, with a planetary gear unit for translating one of the Pilot clutch transferred to the output ramp actuating force for opening and / or closing the friction clutch forms is. The reduction in speed that can be achieved by the planetary gear means that the friction clutch can be closed more gently, which is understood as good shifting comfort.

Description

The invention relates to a clutch actuation system for opening and / or closing a friction clutch and a method for coupling a drive shaft of a motor vehicle engine with a transmission input shaft of a motor vehicle transmission, by means of which a friction clutch, in particular a starting clutch for shifting transmission gears of a motor vehicle transmission, can be actuated.

From the DE 10 2006 028 645 A1 For example, a clutch actuation system for actuating a friction clutch is known. The clutch actuation system includes an electromagnetically actuable pilot clutch coupled to a ball-ramp system. To actuate the friction clutch, the electromagnetic pilot clutch is acted upon via an electromagnet with an actuating force acting in the closing direction of the pilot control clutch. In the presence of a speed difference between an input side and an output side of the pilot clutch, the ramp of the ball-ramp system facing the pilot clutch is rotated, whereby the ramp facing the friction clutch is pushed away in the axial direction. The weggedrückter ramp takes in the axial movement of a pressure plate for frictionally closing the friction clutch, whereby the friction clutch is closed.

There is a constant need to improve the shifting comfort of friction clutches.

It is the object of the invention to show measures that allows a friction clutch with a good shift comfort.

The object is achieved according to the invention by a clutch actuation system with the features of claim 1 and a method for coupling a drive shaft of a motor vehicle engine with a transmission input shaft of a motor vehicle transmission with the features of claim 10. Preferred embodiments of the invention are set forth in the dependent claims, each individually or in combination may represent an aspect of the invention.

According to the invention, a clutch actuation system for opening and / or closing a friction clutch is provided with a ramp system for axially displacing a pressure plate of a friction clutch, wherein the ramp system has an input ramp and an output ramp rotatable relative to the input ramp for varying an axial extension of the ramp system, a pilot clutch for triggering a Twisting the input ramp relative to the output ramp due to a differential speed between a torque input element, in particular drive shaft of an automotive engine, and a Drehmomentausleitungselement, in particular a transmission input shaft of a motor vehicle transmission, and a trip unit for actuating the pilot clutch, wherein between the pilot clutch and the input ramp, a planetary gear for translating one of the Pilot clutch to the output ramp transmitted actuation force to open and / or close the friction clutch is formed.

When the friction clutch to be operated by the pilot clutch of the clutch actuation system is opened, the torque flow between the torque introduction element, in particular, a crankshaft of an automotive engine, and the Drehmomentausleitungselement is interrupted, so that the torque introduction element and the Drehmomentausleitungselement rotate at different speeds. This speed difference can be exploited in a corresponding actuation of the trip unit by means of the clutch actuation system to generate a differential difference based on the difference in speed, with the aid of which the ramps of the ramp system can be rotated to exert a contact force on the pressure plate of the friction clutch via the ramp system. The energy required for the contact force can be derived, in particular, from the torque introduction element by supporting the torque introduction element via the ramp system and the pilot control clutch on the torque diversion element. The pressure plate, or a plurality of pressure plates coupled to each other, can be displaced thereby, so that the friction clutch can be closed. Upon completion of the slip operation of the friction clutch, the rotational speeds of the torque introduction member and the torque extraction member are synchronized with each other so that a rotational speed difference between the torque introduction member and the torque elimination member is no longer present. The ramp system can then remain in the reached position, without the need to initiate a torque and / or a contact pressure via the pilot clutch.

Due to the planetary gear, it is possible to increase the introduced via the pilot clutch differential torque, so that a correspondingly increased torque arrives at the ramp system and a correspondingly increased contact pressure can be generated. This means that a correspondingly lower differential torque is absorbed by the pilot clutch must to produce a desired contact force. The pilot clutch can thereby be designed for a lower torque to be transmitted and dimensioned correspondingly smaller. For example, a Reibbelagsbereich the pilot clutch for frictional transmission of the differential torque may be provided with a smaller friction surface and / or be arranged on a smaller radius. This makes it possible, for example, to provide the pilot clutch radially inside the friction clutch, wherein the pilot clutch and the friction clutch can overlap at least partially in an axial region, in particular in the radial direction. The space requirement can be reduced. At the same time, a reduction of the speed introduced via the pilot control clutch into the ramp system can be achieved by the planetary gear, so that the pressure plate displaced by the ramp system can be moved correspondingly slower and more cautiously when closing the friction clutch. A hard frictional contact with a sudden torque shock can be avoided or at least damped. In particular, when the friction clutch is used as a starting clutch for shifting gears of a motor vehicle transmission, a sudden torque impact on the transmission input shaft can be avoided. By achievable by the planetary gear reduction of the speed, the closing of the friction clutch can be done gently, which is understood as a good shift comfort.

The ramps of the ramp system can slide directly on each other or be rotated relative to each other via at least one ball, a cylinder or other rotatable element. By rotating the ramps relative to each other, the distance of the back facing away from the other opposite ramp rear sides of the input ramp and the output ramp can change, so that correspondingly reduce or increase the axial extent of the ramp system. Preferably, the ramp system may increase its axial extent with both a positive speed difference between the torque introducing element and the torque diverting element and a negative speed difference between the torque introducing element and the torque diverting element. For this purpose, the respective ramps, for example, two at an angle, in particular substantially V-shaped, running away from each other running to the radial plane beveled partial ramps can be provided so that starting from a neutral position with minimum axial extension of the ramp system both a twisting in the one circumferential direction and a Twisting in the reverse circumferential direction leads to an increase in the axial extent of the ramp system. The partial ramps can be directly connected to each other or connected to each other via a non-tapered running in the radial plane intermediate area. The partial ramps can be configured substantially mirror-inverted or have a different pitch and / or length in the circumferential direction. Particularly preferably, the maximum relative angle of rotation of the input ramp to the output ramp is limited for example by at least one stop, whereby, for example, exceeding a maximum wear range of friction linings of the friction clutch can be avoided. Preferably, at least the ramp-shaped subregions of the input ramp and the output ramp are identical, in particular as identical parts, formed. Furthermore, it can be provided that the pressure plate of the friction clutch is formed by the output ramp. The pressure plate of the friction clutch may be formed integrally with the output ramp of the ramp system.

In particular, the maximum torque that can be transmitted by the friction clutch is limited by the design of the ramps of the ramp system, for example by means of stops provided at suitable locations. A contact pressure of the pressure plate can be limited. The maximum transmissible torque for the traction operation may be different or equal to the maximum transmissible torque for the traction operation. In particular, the maximum transferable torque for the overrun operation is lower than for the train operation. An unnecessarily high load on components in the drive train, in particular during overrun operation, can be avoided, so that in particular possible damage to a torsional vibration damper, in particular two-mass flywheel, is avoided.

The pilot control clutch can be configured as a friction clutch, wherein the pilot clutch can be dimensioned in particular significantly smaller than the friction clutch to be actuated by the clutch actuation system. In the closed state of the pilot clutch, the input ramp of the ramp system can be coupled to the torque introduction element or the torque output element.

By the trip unit, the pilot clutch can be opened and / or closed. By provided by the planetary gear ratio, the trip unit can be sized accordingly small. Since only a correspondingly low differential torque must be transmitted from the pilot clutch, a correspondingly low contact pressure provided by the trip unit is already sufficient.

In particular, the planetary gear has functional elements in the form of a sun, a ring gear and at least one meshing with the sun and the hollow wheel planet wheel, which is rotatably supported by a planet carrier on. A suitable for the desired ratio or reduction functional element may be connected to the input ramp of the ramp system, while another functional element may be connected to an output side of the pilot clutch. About the dimensioning of the diameter of the sun gear, the planetary gear and the inner diameter of the ring gear, a suitable transmission ratio can be specified. Optionally, a functional element may be held non-rotatably and / or optionally braked with and / or without slippage in order to be able to set and / or optionally change a desired transmission ratio. The planetary gear is in particular designed and / or connected to the ramp system and the pilot clutch, that a speed introduced by the pilot clutch is reduced and the ramp system, compared to the speed introduced by the pilot clutch speed decreases and at the same time initiated by the pilot clutch Torque is translated and arrives at the ramp system in comparison to the torque introduced by the pilot clutch torque greater torque, whereby a translation of a transmitted from the pilot clutch to the output ramp actuating force for opening and / or closing the friction clutch takes place.

In particular, the trip unit actuates the pilot clutch electromagnetically, in particular by means of a preferably continuously electrically actuated electromagnet. Due to the low contact force required in the pilot control clutch, an electromagnetically generated contact pressure force may be sufficient. In particular, for this purpose, a correspondingly small-sized solenoid can be used, which exerts no unnecessary magnetic forces on other adjacent components due to the low field strength required and weakening of the magnetic force by other components and / or impairment of other components are avoided by the trip unit. In particular, it is possible to not have to gain the force for actuating the friction clutch from the mechanical energy when operating a clutch pedal. Instead, the operation of a clutch pedal can be detected with suitable sensors and converted into electrical signals for driving the trip unit. Changes in the course of the contact force when the friction clutch is actuated and / or due to wear effects during the life of the friction clutch can be decoupled from the moment of resistance when the clutch pedal is actuated, thereby improving the shifting comfort when the friction clutches are actuated over the service life of the friction clutch.

Preferably, the input ramp is designed as a ring gear of the planetary gear. The ramp region of the input ramp may at least partially point radially outward, so that the input ramp can be configured very easily as a closed ring, which may have a radially inwardly facing toothing for the formation of the ring gear. As a result, an already existing component can be used to form a functional element of the planetary gear without providing a separate component for this functional element. The space requirement and the number of components can be kept low.

Particularly preferably, the pilot clutch on a displaceable by means of the trip unit input element and a frictionally engageable with the input element output element, wherein the output member is rotatably connected to a sun gear of the planetary gear. The sun gear can be configured integrally with the output element, so that the space requirement and the number of components can be kept low to provide the planetary gear. The pilot clutch can be positioned radially further in particular in comparison to the friction surfaces of the friction clutch, so that a small space requirement is achieved and a particularly easy connection to the sun gear can succeed.

In particular, either the pilot clutch, in particular the input element of the pilot clutch, a first connecting means, in particular spline, for non-rotatable connection with the Drehmomentausleitungselement, while the output ramp of the ramp system has a second connecting means, in particular spline, for rotationally fixed connection with the torque introduction element, or the output ramp the ramp system has a first connecting means, in particular splines, for non-rotatable connection with the Drehmomentausleitungselement, while the pilot clutch, in particular the input element of the pilot clutch has a second connecting means, in particular spline, for rotationally fixed connection with the torque introduction element. This ensures that when the pilot clutch is closed and the friction clutch is open, a differential torque can be applied to the ramp system for rotating the input ramp relative to the output ramp.

Preferably, the planetary gear has at least one meshing with a sun gear and a ring gear of the planetary gear planet gear, wherein the planet gear is rotatably mounted on a clutch cover of the friction clutch, wherein in particular the clutch cover rotatably connected to the torque introduction element is connectable. A separate planned planetary carrier can be avoided by using an intended anyway clutch cover for this function. For example, the planetary gear may have a pin rotatably mounted in the clutch cover and / or the clutch cover has a non-rotatably connected to the clutch cover, in particular integrally, connected bolts around which the planetary gear can rotate. A braking device, which brakes a separately executed planetary carrier and coupled with the movement of the torque introduction element, can be saved. For this purpose, it is sufficient that the clutch cover is rotatably coupled to the torque introduction element, for example, by a non-rotatable mounting with a counter-plate of the friction clutch.

Particularly preferably, the output ramp is indirectly or directly connected to a return torsion spring for rotating the output ramp in a defined starting position in the absence of contact pressure, in particular, the friction clutch is open in the defined starting position of the output ramp. If the friction clutch is to be opened, the pilot clutch can be opened, so that the ramps of the ramp system can no longer be supported by the pilot clutch. By the spring force of the return spring, the output ramp can be rotated back relative to the input ramp, so that the axial extent of the ramp system can be reduced and the friction clutch is opened. For this purpose, the return torsion spring, which may be configured for example in the manner of a torque sensor, exert a force acting in the tangential direction and / or in the circumferential direction spring force on the output ramp and thereby provide a suitable return torque. Furthermore, it is possible for the return torsion spring, configured, for example, as a leaf spring, to exert a spring force on the pressure plate in an opening direction of the friction clutch, so that the pressure plate exerts an axial force on the output ramp, whereby the output ramp is rotated to reduce the axial extent of the ramp system can.

In particular, the pilot clutch has a displaceable by means of the trip unit input element and a frictionally engageable with the input element output element, wherein the input element is directly or indirectly connected to a return spring for axial positioning of the input member in a defined starting position in the absence of the trip unit deployable release force, wherein in particular, the pilot control clutch is closed in the defined starting position of the input element. The restoring spring designed, for example, as a plate spring can, in the event that the triggering unit does not provide force, position the input element in a defined position with the aid of its spring force, for example a "normally open" or "normally closed" position of the pilot clutch and preferably thereby also provide for the friction clutch.

The invention further relates to a clutch unit with a friction clutch for coupling a drive shaft of a motor vehicle engine with a transmission input shaft of a motor vehicle transmission, wherein the friction clutch a counter plate for introducing a torque and a relative to the counter plate displaceable pressure plate for frictional pressing a clutch disc between the counter plate and the pressure plate for discharging of the torque, and a clutch actuation system, which may be formed and further developed as described above, for displacing the pressure plate. By achievable by the planetary gear of the clutch actuation system reduction of the speed of the closing of the friction clutch can be made more gentle, which is understood as a good shift comfort.

The invention further relates to a drive train of a motor vehicle having a drive shaft of an automotive engine, a transmission input shaft of a motor vehicle transmission and a clutch unit, which may be off and on as described above, for coupling the drive shaft with the transmission input shaft. By achievable by the planetary gear of the clutch actuation system reduction of the speed of the closing of the friction clutch can be made more gentle, which is understood as a good shift comfort.

The invention further relates to a method for coupling a drive shaft of an automotive engine with a transmission input shaft of a motor vehicle transmission by means of a friction clutch, wherein a differential torque generated by a speed difference between the drive shaft and the transmission input shaft by means of a planetary gear, in particular part of a clutch actuation system, as above described andundertransformed, is translated and the translated differential torque is used to operate the friction clutch. By achievable by the planetary gear reduction speed, the closing of the friction clutch can be done gently, which is good Switching comfort is understood. The method may in particular be designed and developed as described above with reference to the clutch actuation system.

The invention will now be described by way of example with reference to the accompanying drawings with reference to preferred embodiments, wherein the features shown below, both individually and in combination may represent an aspect of the invention. Show it:

1 FIG. 2 is a schematic diagram of a clutch actuation system. FIG.

2 a schematic sectional view of a friction clutch with the clutch actuation system 1 and

3 : A schematic sectional view of a detail of the clutch actuation system 2 ,

This in 1 strongly schematically illustrated clutch actuation system 10 is between one with a motor vehicle engine 12 coupled torque introduction element 14 , For example, a crankshaft, an output side of a torsional vibration damper or a clutch cover 16 a friction clutch 18 , and one with a motor vehicle transmission 20 coupled torque diverting element 22 , For example, a transmission input shaft provided. The clutch actuation system 10 has a pilot clutch 24 on, with the help of a trip unit 26 can be opened and closed. For this purpose, the trip unit 26 one with the torque diverting element 22 rotatably connected input element 28 axially displace to a frictional engagement with an output element 30 cause and / or cancel. The trip unit 26 is at a voltage source 32 connected and can be the input element 28 electromagnetically against a spring force of a spring configured as a plate spring return spring 34 in itself, to the pilot clutch 24 to open.

The starting element 30 the pilot clutch 24 is with a sun wheel 36 a planetary gear 38 connected. The sun wheel 36 meshes with at least one planetary gear 40 that by one through the clutch cover 16 the friction clutch 18 trained planet carrier 42 is rotatably mounted and with a ring gear 44 combs.

The ring gear 44 of the planetary gear 38 is with an entrance ramp 46 a ramp system 48 connected. The entrance ramp 46 is on one side about a bearing 50 on the torque introduction element 14 and on the opposite side forming the ramp shape via a ball 52 at an exit ramp 54 supported with a corresponding ramp shape. With the help of an example designed as a torque sensor return torsion spring 55 can the output ramp 54 be turned back to a defined home position, if none of the pilot clutch 24 initiated moment for rotating the ramps 46 . 54 is applied.

As in 2 shown is the output ramp 54 of the ramp system 48 with a pressure plate 56 the friction clutch 18 a clutch unit 58 connected or even made in one piece. With a relative rotation of the input ramp 46 to the exit ramp 54 may be the axial extent of the ramp system 48 enlarge, so that the pressure plate 56 in the axial direction on one with the clutch cover 16 firmly connected counter plate 60 can be shifted to at least one clutch disc 62 optionally with the help of intermediate Zusatzanpressplatten 64 to frictionally compress and thereby the friction clutch 18 close. That over the clutch cover 16 and the counter-plate 60 incoming torque of the motor vehicle engine 12 can then have a clutch disc carrier 66 if necessary, a disc damper 68 may have, to a transmission input shaft of the motor vehicle transmission 20 be transmitted.

As in 3 shown has the trip unit 26 a variety of wire turns 70 which form a coil and with the help of a yoke 72 form an electromagnet. The trip unit 26 can thereby generate a magnetic force to the input element 28 to open the pilot clutch 24 to be used in the axial direction. The input element 28 can via an entrance warehouse 74 relatively rotatable, for example on the trip unit 26 be stored. At the same time, through the entrance warehouse 74 a minimum distance of the input element 28 to the yoke 72 be complied with, so that a direct contact can be avoided. The starting element 30 can have a home warehouse 76 for example, on the clutch cover 16 be relatively rotatably supported and stored.

LIST OF REFERENCE NUMBERS

10

 Clutch actuation system

12

 Automotive engine

14

 Torque input element

16

 clutch cover

18

 friction clutch

20

 Motor vehicle transmission

22

 Drehmomentausleitungselement

24

 pilot clutch

26

 trip unit

28

 input element

30

 output element

32

 voltage source

34

 Return spring

36

 sun

38

 planetary gear

40

 planet

42

 planet carrier

44

 ring gear

46

 entrance ramp

48

 ramp system

50

 camp

52

 Bullet

54

 exit ramp

55

 Rear torsion spring

56

 pressure plate

58

 clutch unit

60

 counterplate

62

 clutch disc

64

 Zusatzanpressplatte

66

 Clutch disc carrier

68

 disc damper

70

 wire turn

72

 yoke

74

 receiving warehouse

76

 base camp

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 102006028645 A1 [0002]

Claims (10)

Clutch actuation system for opening and / or closing a friction clutch ( 18 ), with a ramp system ( 48 ) for axially displacing a pressure plate ( 56 ) a friction clutch ( 18 ), whereby the ramp system ( 48 ) an entrance ramp ( 46 ) and one relative to the input ramp ( 46 ) for changing an axial extent of the ramp system ( 48 ) rotatable output ramp ( 54 ), a pilot clutch ( 24 ) for triggering a twisting of the input ramp ( 46 ) relative to the output ramp ( 54 ) due to a differential speed between a torque input element ( 14 ), in particular drive shaft of a motor vehicle engine ( 12 ), and a torque extraction element ( 22 ), in particular a transmission input shaft of a motor vehicle transmission ( 20 ), and a trip unit ( 26 ) for actuating the pilot control clutch ( 24 ), between the pilot clutch ( 24 ) and the entrance ramp ( 46 ) a planetary gear ( 38 ) for the translation of one of the pilot clutch ( 24 ) to the output ramp ( 54 ) transmitted actuating force for opening and / or closing the friction clutch ( 16 ) is trained. Clutch actuation system according to claim 1, characterized in that the trip unit ( 26 ) the pilot clutch ( 24 ) Electromagnetically, in particular by means of a preferably continuously electrically actuated electromagnet actuated. Clutch actuation system according to claim 1 or 2, characterized in that the input ramp ( 46 ) as a ring gear ( 44 ) of the planetary gear ( 38 ) is configured. Clutch actuation system according to one of claims 1 to 3, characterized in that the pilot clutch ( 24 ) one with the help of the trip unit ( 26 ) displaceable input element ( 28 ) and a frictionally engaged with the input element ( 28 ) detachable output element ( 30 ), wherein the output element ( 30 ) with a sun wheel ( 36 ) of the planetary gear ( 38 ) is rotatably connected. Clutch actuation system according to one of claims 1 to 4, characterized in that either the pilot clutch ( 24 ), in particular the input element ( 28 ) of the pilot clutch ( 24 ), a first connecting means, in particular spline, for the rotationally fixed connection with the Drehmomentausleitungselement ( 22 ), while the output ramp ( 54 ) of the ramp system ( 48 ) a second connecting means, in particular spline, for the rotationally fixed connection with the torque introduction element ( 14 ), or the output ramp ( 54 ) of the ramp system ( 48 ) a first connecting means, in particular splines, for the rotationally fixed connection with the Drehmomentausleitungselement ( 22 ), while the pilot clutch ( 24 ), in particular the input element ( 28 ) of the pilot clutch ( 24 ) a second connecting means, in particular spline, for the rotationally fixed connection with the torque introduction element ( 14 ) having. Clutch actuation system according to one of claims 1 to 5, characterized in that the planetary gear ( 38 ) at least one with a sun gear ( 36 ) and a ring gear ( 44 ) of the planetary gear ( 38 ) meshing planetary gear ( 40 ), wherein the planetary gear ( 40 ) rotatably mounted on a clutch cover ( 16 ) of the friction clutch ( 18 ) is mounted, in particular the clutch cover ( 16 ) rotatably with the torque introduction element ( 14 ) is connectable. Clutch actuation system according to one of claims 1 to 6, characterized in that the output ramp ( 54 ) directly or indirectly with a reverse torsion spring ( 55 ) for rotating the output ramp ( 54 ) is connected in a defined starting position in the absence of contact pressure, wherein in particular the friction clutch ( 18 ) in the defined starting position of the output ramp ( 54 ) is open. Clutch actuation system according to one of claims 1 to 7, characterized in that the pilot clutch ( 24 ) one with the help of the trip unit ( 26 ) displaceable input element ( 28 ) and a frictionally engaged with the input element ( 28 ) detachable output element ( 30 ), wherein the input element ( 28 ) directly or indirectly with a return spring ( 34 ) for the axial positioning of the input element ( 28 ) in a defined starting position in the absence of the trip unit ( 26 ) releasable release force is connected, in particular the pilot clutch ( 24 ) in the defined starting position of the input element ( 28 ) closed is. Clutch unit with a friction clutch ( 18 ) for coupling a drive shaft of a motor vehicle engine ( 12 ) with a transmission input shaft of a motor vehicle transmission ( 20 ), wherein the friction clutch ( 18 ) a counter plate ( 60 ) for introducing a torque and a relative to the counter-plate ( 60 ) displaceable pressure plate ( 56 ) for the frictional compression of a clutch disc ( 62 ) between the counter plate ( 60 ) and the pressure plate ( 56 ) for discharging the torque, and a clutch actuating system ( 10 ) according to one of claims 1 to 8 for displacing the pressure plate ( 56 ). Method for coupling a drive shaft of a motor vehicle engine ( 12 ) with a transmission input shaft of a motor vehicle transmission ( 20 ) by means of a friction clutch ( 18 ), in which a differential torque generated by a rotational speed difference between the drive shaft and the transmission input shaft is produced by means of a planetary gearing ( 38 ), in particular part of a clutch actuation system ( 10 ) according to one of claims 1 to 8, is translated and the translated differential torque for actuating the friction clutch ( 18 ) is used.

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