DE102018131753A1 - Coupling system - Google Patents

Abstract

A clutch system (42) is provided with a friction clutch (46) for transmitting a torque between a torque introduction element (44) and a torque discharge element (48), a ramp system (58) for axially displacing a pressure plate (66) of the friction clutch (46), wherein the ramp system (58) has an input ramp (56) and an output ramp (62) which can be rotated relative to the input ramp (56) in order to change an axial extent of the ramp system (58), a pilot clutch (50) for triggering rotation of the input ramp (56) relative to the output ramp (62) as a result of a differential speed between the torque introduction element (44) and the torque extraction element (48), and an electromagnet (70) for opening and / or closing the pilot clutch (50), the pilot clutch (50) having a cone (52 ) and has a conical pot (54) which can be coupled to the cone (52) by friction. This enables easy and efficient adaptation of a torque transmission in a drive train (8) to different driving strategies.

Description

The invention relates to a clutch system with the aid of which a drive shaft of a motor vehicle engine can be coupled to at least one transmission input shaft of a motor vehicle transmission, in particular in the case of a hybrid motor vehicle.

Out WO 2015/070851 A1 a clutch system in the manner of a so-called booster clutch is known, in which a friction clutch designed as a separating clutch can be actuated with the aid of a ramp system. To close the friction clutch, the ramp system can change its axial extent by means of an output ramp which can be rotated relative to an input ramp and thereby axially shift a pressure plate of the friction clutch. As a result, a clutch disc can be frictionally pressed between the pressure plate and a counter plate of the friction clutch. An actuating device that can be actuated electromagnetically by an eddy current brake is provided for actuating the ramp system.

There is a constant need to be able to easily and efficiently adapt a torque transmission in a drive train, in particular a hybrid motor vehicle, to different driving strategies.

It is the object of the invention to show measures which enable easy and efficient adaptation of a torque transmission in a drive train, in particular a hybrid motor vehicle, to different driving strategies.

The object is achieved according to the invention by a coupling system having the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the description below, which can each represent an aspect of the invention individually or in combination.

According to the invention, a clutch system for coupling a drive shaft of a motor vehicle engine with at least one transmission input shaft of a motor vehicle transmission is provided with a friction clutch, in particular designed as a multi-plate clutch, for transmitting a torque between a torque input element, in particular drive shaft of the motor vehicle engine, and a torque output element, in particular transmission input shaft of the motor vehicle transmission Ramp system for axially displacing a pressure plate of the 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 the torque input element and the torque output element , and an electromagnet for opening and / or closing the pilot clutch, the pilot clutch having a cone and a cone cup which can be frictionally coupled to the cone.

The pilot clutch can thereby be configured as a cone clutch that can be actuated electromagnetically with the aid of the electromagnet. The cone clutch enables a large frictional contact surface in a narrow installation space, so that the cone clutch can be provided slightly radially inside the friction clutch and yet can transmit sufficient torque and support the friction clutch in the closed state. In addition, a ferromagnetic body can be provided on the larger diameter of the cone-shaped cone, in particular, and / or on a cone pot that axially covers the smaller diameter of the cone, on which the electromagnet can engage to open and / or close the cone coupling. As a result, it is not necessary to produce the cone or the cone cup from a ferromagnetic material and in particular to select the materials for the cone and the cone cup with regard to a suitable frictional connection. In particular, the electromagnet can attract the ferromagnetic body to open the cone clutch and / or repel the ferromagnetic body to close the cone clutch. Due to the low use of electrical energy in the electromagnet, it is easily possible to throw off an internal combustion engine from the drive train by opening the friction clutch, so that the drag torques of the internal combustion engine cannot brake the motor vehicle, for example in a sailing operation or purely electrical operation. An electrical machine can be coupled to the torque output element, which can drive the motor vehicle purely electrically when the friction clutch is open in motor operation and / or recuperate electrical energy in generator operation. When the friction clutch is closed, the electrical machine can rotate without load to enable a purely motor drive, provide additional electrical drive energy in motor operation (“booster operation”) or convert mechanical energy of the internal combustion engine into storable electrical energy in generator operation. The torque diversion element can form a rotor of the electrical machine, the ramp system and / or the pilot clutch and / or the electromagnet being able to be provided radially within the rotor in a radius region and thereby being designed to be integrated in the rotor can. The pilot control clutch, which is designed as a cone clutch and can be operated easily and in an energy-saving manner by the electromagnet, can support a significant torque via the pilot clutch in the closed state of the friction clutch, so that torque transmission in a drive train, in particular a hybrid motor vehicle, can be easily and efficiently adjusted. different driving strategies.

The pilot clutch, the ramp system and the friction clutch can together form a so-called booster clutch. In the closed state of the friction clutch, the torque introduction element and the torque discharge element have essentially the same speed in non-slip operation. When the friction clutch is open, the torque introduction element and the torque discharge element can rotate at a different speed, so that a speed difference between the torque introduction element and the torque discharge element is established. The torque flowing via the torque introduction element and the friction clutch can flow at least partially via the at least partially closed pilot clutch, so that in the closed state of the pilot clutch torque transmission can take place at least temporarily via the ramp system, whereby component loads can be reduced. In particular, when the input ramp is rotated relative to the output ramp, the pilot clutch produces a slip frictional connection between the torque input element and the torque output element. Due to the slipping frictional engagement, a speed difference can be generated in the pilot clutch, which can be used to rotate the input ramp relative to the output ramp. At the same time, a torque can also be transmitted in slip operation, which can be forwarded to the ramp system in order to provide a correspondingly high contact pressure for the contact plate. If a speed adjustment between the torque input element and the torque output element has not yet taken place, the slipping pilot clutch can convert the speed difference into a relative rotation of the input ramp to the output ramp via a suitable coupling of the ramp system with the pilot clutch. As a result, the axial extent of the ramp system can change as a result of the speed difference within the pilot clutch and thus as a result of the speed difference between the torque-introducing element and the torque-diverting element. Due to the changing extension of the ramp system, the pressure plate can be displaced to close the friction clutch, a displacement force for displacing the pressure plate being able to be branched off from the torque transmitted via the pilot clutch. If the extension of the ramp system has changed to such an extent that, for example, the pressure plate presses a clutch disc and / or disks of a multi-plate clutch, the rotational speeds of the torque-initiating element and the torque-diverting element are synchronized with one another after the end of the slip operation, so that there is no longer a speed difference. The ramp system can then remain in the position reached.

To open the friction clutch, the pilot clutch can cancel or at least reduce torque support of the input ramp of the ramp system. Due to the frictional forces acting on the friction partners of the friction clutch, the friction partners can be automatically pushed away from one another, a return spring preferably being provided in order to automatically move the friction clutch into the open position when no actuating force is applied via the pressure plate. For this purpose, additionally or alternatively, for example, corrugated springs can be provided for separating the friction partners from one another. The pressure plate can thereby be pressed into its initial position corresponding to the open position of the friction clutch, at the same time the ramp system being rotated back in the opposite direction, in which in particular the axial extent of the ramp system is reduced.

In the closed position of the friction clutch, the major part of the torque to be transmitted can take place via the friction pair (s) of the friction clutch, a smaller proportion of the torque to be transmitted can be transmitted via the pilot clutch. As a result, a correspondingly high contact pressure can be exerted on the pressure plate via the pilot clutch, so that a correspondingly higher torque can be transmitted safely and without slipping. In this case, by means of a suitable choice of the ramp gradient of the ramp system, a force transmission can be achieved, so that an increased geared pressing force can be achieved with a low actuating force for actuating the pilot clutch. Furthermore, part of the torque to be transmitted can be used to provide the contact pressure, so that the contact pressure can be fed from a further energy source. Due to the actuating force acting on the pressure plate only indirectly via the pilot clutch, a power boost and / or a torque branch can be achieved from the torque to be transmitted to close the friction clutch via the pilot clutch, so that the friction clutch can be frictionally closed with a significantly increased contact force, which enables the friction clutch to be securely closed with little design effort.

Force can be increased via the ramp slope of the ramps of the ramp system, so that, in comparison to the contact force achievable on the contact plate, a significantly lower actuating force is required to close the pilot clutch. As a result, an actuation system, in particular an electromagnetic actuation system, can be dimensioned to be significantly smaller and more space-saving than if the actuation system were to move the pressure plate directly. It is also possible to move the pilot clutch out of the area of the pressure plate. As a result, the pilot clutch can be positioned at least to a large extent radially inward of the pressure plate, in particular in comparison to the pressure plate, so that installation space can be used radially inside for friction linings of the friction clutch. The friction contacts of the friction clutch can thus be provided in a comparatively far radially outer area, so that a correspondingly small extension of the friction clutch radially inward is required in order to be able to realize a correspondingly large friction surface. Here, the knowledge can be exploited that the pilot clutch only needs to transmit a small torque in order to actuate the ramp system, so that a correspondingly smaller friction surface on a smaller average friction radius compared to the clutch disc is already sufficient.

The output ramp can be coupled in a rotationally fixed but axially movable manner, in particular via the pressure plate, to the torque diversion element. As a result, the output ramp coupled to the torque output element and the input ramp which can be coupled to the torque input element via the pilot clutch can be rotated relative to one another at a differential speed between the torque output element and the torque input element. The ramps of the ramp system can slide directly onto one another or can be rotated relative to one another via at least one ball, a cylinder or other rotatable element, so that a ball-ramp system can be formed. By rotating the ramps relative to one another, the distance between the rear sides of the input ramp and the output ramp pointing away from the respective other opposite ramp can change, so that the axial extension of the ramp system can decrease or increase accordingly. The maximum relative angle of rotation of the input ramp to the output ramp is particularly preferably limited, for example, by at least one stop, as a result of which, for example, it is possible to avoid exceeding a maximum wear range of friction linings of the friction clutch. The ramp system is preferably positioned radially inside the friction clutch, in particular the ramp system being arranged partially, preferably to a large extent, in a common axial area with the friction clutch, so that the ramp system can be nested in the friction clutch to save space. In this case, the output ramp can have an actuating flange which projects radially outwards and which can optionally be guided past other internals of the coupling system. The actuating flange can be connected to the pressure plate or can form the pressure plate in one piece in its radially outer edge region.

In particular, the cone or the cone pot is formed in one piece with the entrance ramp. The number of components can be kept low.

Preferably, a ferromagnetic spring element, which is fastened to the cone cup or to the cone, in particular designed as a plate spring, is provided for closing the pilot clutch, the electromagnet and the spring element being designed to electromagnetically attract the spring element on the electromagnet to open the pilot clutch. The electromagnet can exert an electromagnetic force on the spring element, as a result of which the spring element can be compressed or pressed apart. The spring element can take the part of the pilot clutch attached to the spring element in order to open or close the pilot clutch by an axial relative movement of the cone cup to the cone. The spring element is in particular designed as a plate spring, which has a particularly small installation space in the axial direction, so that the magnetic forces which can be attacked on the spring element are comparatively large in the open and in the closed position of the pilot clutch. This can prevent the spring element from being moved so far away from the electromagnet that the magnetic force generated by the electromagnet is not sufficient to attract the spring element and to open the pilot clutch.

An electrical machine for driving a motor vehicle is particularly preferably provided, the torque deriving element being part of a rotor of the electrical machine, the electromagnet being able to be supplied with electrical energy by the electrical machine. If a purely electrical drive of the motor vehicle by the electrical machine is desired, the electrical machine to be put into motor operation and electrically introduce a torque into the torque output element. At the same time, part of the electrical energy used in the electrical machine during motor operation can be diverted to the electromagnets, so that the pilot clutch is automatically opened and the internal combustion engine is thrown off the drive train. If electrical recuperation is to be carried out, part of the electrical energy generated during generator operation of the electrical machine can be diverted to the electromagnets, so that the pilot clutch is automatically opened and the internal combustion engine is thrown off the drive train.

• 1: eine schematische Prinzipdarstellung eines Hybrid-Antriebsstrangs,
• 2: eine schematische perspektivische Schnittdarstellung eines Kupplungssystems für den Hybrid-Antriebsstrang aus 1,
• 3: eine schematische Schnittansicht des Kupplungssystems aus 2 und
• 4: eine schematische Detailansicht des Kupplungssystems aus 3.

In the following, the invention is explained by way of example with reference to the attached drawings using preferred exemplary embodiments, the features shown below being able to represent an aspect of the invention both individually and in combination. Show it:

• 1 : a schematic diagram of a hybrid powertrain,
• 2nd : A schematic perspective sectional view of a clutch system for the hybrid drive train from 1 ,
• 3rd : a schematic sectional view of the coupling system from 2nd and
• 4th : a schematic detailed view of the coupling system from 3rd .

The in 1 Drive train intended for a hybrid motor vehicle 8th has an internal combustion engine designed in particular as an internal combustion engine 10th on whose drive shaft 12 via a first clutch K1 with a transmission input shaft 14 a motor vehicle transmission 16 can be coupled. If the automotive transmission 16 is designed as a double clutch transmission, the drive shaft 12 via a second clutch, not shown K2 with a further transmission input shaft of the motor vehicle transmission 16 be coupled. The automotive transmission 16 can via an output shaft 18th and a differential gear 20th with front axles 22 be coupled to front wheels 24th to drive. Additionally or alternatively, the motor vehicle transmission can 16 via a rear output shaft 26 and a rear differential gear 28 with rear axles 30th be coupled to rear wheels 32 to drive. In the illustrated embodiment is between the drive shaft 12 the internal combustion engine 10th and the transmission input shaft 14 of the motor vehicle transmission 16 an intermediate shaft 34 provided that over the first clutch K1 with the transmission input shaft 14 and another clutch K0 with the drive shaft 12 can be coupled.

An electrical machine 36 for the electric drive of the motor vehicle can be at various points on the drive train 8th be coupled. In a first position P1 can the electrical machine 36 on the drive shaft 12 the internal combustion engine 10th be coupled, the drive shaft 12 a rotor 38 of the electrical machine 36 can train. For this the rotor 38 Have permanent magnets with electromagnets of a stator 40 of the electrical machine 36 can work together. In a second position P2 can the electrical machine 36 on the intermediate shaft 34 be coupled, the intermediate shaft 34 the rotor 38 of the electrical machine 36 can train. In a third position P3 can the electric machine 36 on the output shaft 18th be coupled, the output shaft 18th the rotor 38 of the electrical machine 36 can train. The electrical machine can do the same 36 on the rear output shaft 26 be coupled, the rear output shaft 26 the rotor 38 of the electrical machine 36 can train. In a fourth position P4 can the electrical machine 36 on the front axle 22 be coupled, the front axle 22 the rotor 38 of the electrical machine 36 can train. The electrical machine can do the same 36 on the rear axle 30th be coupled, the rear axle 30th the rotor 38 of the electrical machine 36 can train. It is also possible to have an electrical machine as an electrically driven wheel hub motor in the respective front wheel 24th and / or the respective rear wheel 32 to provide. In another position P0 can the electrical machine 36 on one of the motor vehicle transmission 16 end pointing away from the internal combustion engine 10th protruding shaft end of the drive shaft 12 the internal combustion engine 10th be coupled, the shaft end of the drive shaft 12 the rotor 38 of the electrical machine 36 can train. This shaft end of the drive shaft 12 is usually used to drive other motor vehicle units via a belt drive.

This in 2nd and 3rd coupling system shown 42 is for actuating the further clutch K0 of the drive train 8th provided where the electrical machine 36 in the second position P2 with the intermediate shaft 34 is coupled. The clutch system 42 has a torque introduction element 44 on that rotatably with the drive shaft 12 is attached. The torque introduction element 44 forms an inner disk carrier of a friction clutch designed as a disk clutch 46 off and can be in the closed state of the friction clutch 46 a torque of the drive shaft 12 on a torque diversion element designed as an outer disk carrier 48 transfer. The torque rejection element 48 is non-rotatable with the intermediate shaft 34 connected. In addition, on the outside of the Torque diversion element 48 Permanent magnets provided to the rotor 38 of the electrical machine 36 to train. For actuating the friction clutch 46 is a pilot clutch 50 intended. The pilot clutch 50 is designed as a cone coupling and has a cone 52 on, the friction lock with an axially displaceable cone pot 54 can be coupled. The cone pot 54 is rotatably but axially displaceable with the drive shaft 12 coupled. The cone 52 is in one piece with an entrance ramp 56 of a ramp system 58 trained, alternatively also the cone pot 54 in one piece with an entrance ramp 56 can be formed and the cone 52 non-rotatable but axially displaceable with the drive shaft 12 can be coupled. The entrance ramp 56 is about bullets 60 on an exit ramp 62 stored. If the pilot clutch 50 is closed, the entrance ramp turns 56 with the speed of the drive shaft 12 and can be relative to the exit ramp 62 twist. This can result in the axial extension of the ramp system 58 increase. The exit ramp 62 is via a transmission flange 64 with a pressure plate 66 the friction clutch 46 attached so that the pressure plate 66 the axial displacement of the exit ramp 62 can go along and the friction clutch 46 closes. The pressure plate 66 is rotatably but axially displaceable with the torque diversion element 48 coupled so that the output ramp 62 non-rotatable with the torque rejection element 48 is coupled and with the speed of the torque diversion element 48 turns. If the friction clutch 46 is closed, the torque introduction element rotate 44 and the torque diverting element 48 at the same speed, so that there is no relative rotation of the input ramp 46 to the exit ramp 62 more occurs. To open the friction clutch 46 can the pilot clutch 50 be opened so that the entrance ramp 46 no longer on the drive shaft 12 is supported. The pressure plate 66 can depend on the axial spring forces of the friction clutch 46 in one of the open positions of the friction clutch 46 corresponding axial relative position are shifted, which also the output ramp 62 on the entrance ramp 56 is pressed and the ramp system 58 is turned back into a relative position with a smaller axial extent.

The pilot clutch 50 can with the help of a in a support sleeve 68 Tilt-proof and precisely aligned electromagnets 70 be operated. The support sleeve 68 and / or the entrance ramp 56 can on the drive shaft 12 be relatively rotatable. As in 4th an electrically generated magnetic field can be represented 72 on the cone pot 54 past in a spring element designed as a plate spring 74 be concentrated. The spring element 74 is fixed with the cone pot 54 attached. If the electromagnet 72 no magnetic field 72 generated, the spring element 74 the cone pot 54 to the cone 52 press on and thereby the pilot clutch 50 conclude. If the electromagnet 72 the magnetic field 72 generated, the electromagnet 72 the spring element made of a ferroelectric material 74 tighten so that the spring element 74 its axial extent is reduced and that with the spring element 74 attached cone pot 54 from the cone 52 subtracts, causing the pilot clutch 50 is opened.

Reference symbol list

8th

Powertrain

10th

Internal combustion engine

12

drive shaft

14

Transmission input shaft

16

Automotive transmission

18th

Output shaft

20th

Differential gear

22

Front axle

24th

Front wheel

26

Rear output shaft

28

Rear differential gear

30th

Rear axle

32

Rear wheel

34

Intermediate shaft

36

electrical machine

38

rotor

40

stator

42

Coupling system

44

Torque introduction element

46

Friction clutch

48

Torque diversion element

50

Pilot clutch

52

cone

54

Cone pot

56

Entrance ramp

58

Ramp system

60

Bullet

62

Exit ramp

64

Transmission flange

66

Pressure plate

68

Support sleeve

70

Electromagnets

72

Magnetic field

74

Spring element

K0

further clutch

K1

first clutch

P0

further position

P1

first position

P2

second position

P3

third position

P4

fourth position

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

• WO 2015/070851 A1 [0002]

Claims (4)

Coupling system for coupling a drive shaft (12) of a motor vehicle engine with at least one transmission input shaft (14) of a motor vehicle transmission (16), with a friction clutch (46), in particular designed as a multi-plate clutch, for transmitting a torque between a torque introduction element (44), in particular the drive shaft (12) of the motor vehicle engine, and a torque transmission element (48), in particular transmission input shaft (14) of the motor vehicle transmission (16), a ramp system (58) for axially displacing a pressure plate (66) of the friction clutch (46), the ramp system (58) having an input ramp (56) and an output ramp which can be rotated relative to the input ramp (56) in order to change an axial extent of the ramp system (58) (62) has a pilot clutch (50) for triggering rotation of the input ramp (56) relative to the output ramp (62) as a result of a differential speed between the torque introduction element (44) and the torque extraction element (48), and an electromagnet (70) for opening and / or closing the pilot clutch (50), wherein the pilot clutch (50) has a cone (52) and a cone cup (54) which can be frictionally coupled to the cone (52). Coupling system after Claim 1 characterized in that the cone (52) or the cone pot (54) is formed in one piece with the entrance ramp (56). Coupling system after Claim 1 or 2nd characterized in that a ferromagnetic spring element (74), in particular in the form of a plate spring, fastened to the cone pot (54) or to the cone (52) is provided for closing the pilot clutch (50), the electromagnet (70) and the spring element ( 74) are designed to open the pilot clutch (50), the spring element (74) on the electromagnet (70) to attract electromagnetically. Coupling system according to one of the Claims 1 to 3rd characterized in that an electrical machine (36) is provided for driving a motor vehicle, the torque-diverting element (48) being part of a rotor (38) of the electrical machine (36), the electromagnet (70) being removed from the electrical machine (36) can be supplied with electrical energy.

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