FR3134862A1 - CLUTCH DISC WITH FREEWHEEL DEVICE INCLUDING TWO RAMP SYSTEMS - Google Patents

Abstract

The clutch disc 2 described in the present description comprises a freewheel device 8 arranged radially inside with two ramp systems 13, 15 capable of rotating relative to each other, the rotation of the first system of ramps 13 causing, by means of a free control wheel 22, an axial shift of the second system of ramps 15, which causes an axial movement of the outer discs 7 and the inner discs 12 in the direction of actuation 21, so that in engine braking speed, a torque can be transmitted between the friction lining 3 and the hub 10 via the disc block. When the control freewheel 22 interrupts, in deceleration mode, the transmission of torque, the spring device 19 causes the ramp systems 13, 15 to return backwards, and the friction connection in the disc block is released. The transmission of torque via the inner discs 12 and the outer discs 7 is thus interrupted, so that when the clutch is engaged, a freewheeling mode can be implemented, the internal combustion engine 202, coupled to the friction lining 3, which can rotate independently of the gearbox input shaft 203, coupled to the hub 10. [Fig. 1]

Description

CLUTCH DISC WITH FREEWHEEL DEVICE INCLUDING TWO RAMP SYSTEMS

The present invention relates to a clutch disc with an integrated freewheel device, which is preferably intended for use in clutches of motor vehicles, in particular equipped with a hybrid drive train.

Vehicles equipped with a hybrid powertrain feature an internal combustion engine and at least one electric motor as a torque source. It is known to operate a hybrid motor vehicle equipped with an automatically controlled clutch in freewheel mode, in which the internal combustion engine operates at idle and is decoupled from the gearbox, so that the internal combustion engine does not does not act as an engine brake. Furthermore, in such motor vehicles, it is possible to operate the motor vehicle solely by using the at least one electric motor as a torque source, for example when starting or at low speed. In both operating modes, it is necessary to decouple the internal combustion engine from the gearbox. If the motor vehicle does not have an automatically controlled clutch but rather a manually controlled clutch, the operating modes mentioned cannot be used straight away.

On this basis, the objective of the present invention is to at least partially solve the problems known from the state of the art.

This objective is achieved by means of the features of independent claim 1. Further advantageous embodiments of the invention are contained in the dependent claims. The features listed individually in the dependent claims can be combined with each other in a technologically meaningful manner and can define further embodiments of the invention. Furthermore, the features contained in the claims are specified and explained in greater detail in the description, with other preferred embodiments of the invention being presented.

According to the invention, the clutch disc comprises a friction lining, a freewheel device which is formed radially inside the friction lining relative to an axis of rotation of the clutch disc, a clutch hub connection to a shaft and a disc flange, with which the friction lining is integral in rotation, the freewheel device comprising an external disc carrier coupled integrally in rotation with the disc flange and an internal disc carrier coupled integrally in rotation to the hub, at least one outer disc being coupled to the outer disc carrier so as to be able to be moved by complementarity of shape and in the direction of the axis of rotation and at least one inner disc being coupled to the inner disc carrier so to be able to be moved by complementarity of shape and in the direction of the axis of rotation, the interior disks and the exterior disks being arranged alternately in the direction of the axis of rotation and being able to be brought into connection by releasable friction the one with the other by a relative movement with respect to one another in an actuation direction, the freewheel device comprising a first ramp system comprising at least a first ramp and a second ramp system comprising at least at least one second ramp, which is designed to correspond to a first ramp, the at least one second ramp being able to be placed on an inner disc in the direction of actuation and via a spring device acting in the direction opposite to the direction of actuation being coupled to the disc flange, a control freewheel being formed with a locking direction and an opposite freewheel rotation direction, the control freewheel being operatively coupled to the first ramp system during rotation in the blocking direction, so that a rotation of the first ramp system in a closing direction of rotation around the axis of rotation and a movement of the second ramp system in the actuation direction takes place via the first and second corresponding ramps, rotation of the free control wheel in the direction of free wheel rotation by the spring device causing movement of the second ramp system against the direction of actuation and thus a rotation of the first system of ramps against the direction of closing rotation around the axis of rotation.

The clutch disc is usually used in a friction clutch and can transmit torque through friction by tightening the friction lining, for example by means of a pressure plate and a counter pressure plate. Particularly in a hybrid powertrain of a motor vehicle, in which both an internal combustion engine and at least one electric motor can serve as a torque source, a connection with the internal combustion engine can be established in a releasable manner by via the friction lining, so the friction lining should be understood as an input to the clutch disc for torque. At the same time, the clutch disc can usually be coupled to a shaft via the hub, so the hub should be understood as the clutch disc's output for torque. To engage the gears, the frictional connection between the friction lining and the other components of the friction clutch, including the pressure plate and the back pressure plate, is released. The freewheeling device allows both a freewheeling function and fully electric driving to be achieved, without having to disengage the friction clutch.

The latter is activated and deactivated via the control freewheel. The control freewheel is aligned so that the rotation of the control freewheel corresponds in the direction of freewheel rotation to the deceleration speed of the motor vehicle, in that the input shaft of the gearbox rotates faster than the crankshaft of the internal combustion engine. In this case, the control freewheel rotates in the direction of freewheel rotation and does not transmit any torque, so that freewheeling mode can be implemented. In engine braking mode, that is to say when the internal combustion engine is running and the friction lining with the disc flange turns faster than the hub, the control freewheel changes direction to rotate in the direction blocking, so that the control freewheel transmits the torque to the first ramp system. This, which is mounted axially on the disc flange, rotates on the latter in the direction of closing rotation. Due to the rotation of the at least one first ramp, it slides along the corresponding second ramp, which is designed to correspond to the first ramp. Thus, the second ramp, and therefore the second system of ramps, move in the direction of actuation, so that the second system of ramps shifts one of the interior discs in the direction of actuation, thus forming a composite of friction of outer and inner discs. Torque can now be transmitted between input and output via the clutch disc.

When the engine braking speed is interrupted, the control freewheel switches to rotation in the freewheel direction, the torque is no longer transmitted by the control freewheel. There is therefore no longer any force exerted by the control circuit in the direction of actuation on the second ramp system. In this case, the spring device exerts a restoring force on the second ramp system, which causes the second ramp system to move in the direction opposite to the direction of actuation. As a result, the frictional connection between the outer and inner discs is released and the transmission of torque via the clutch disc is interrupted. At the same time, the movement of the second ramp system causes the first ramp system to move backwards.

Thus the clutch disc makes it possible to implement freewheeling and an electric driving mode in hybrid powertrains without the corresponding friction clutch having to be opened. A manually operated friction clutch can also be equipped with a freewheel function.

A first ramp and a second ramp are preferably coupled together by at least one ball. The ball design reduces the frictional forces to be overcome between the ramps when the ramp system is operated. The assembly constituted by a first system of ramps comprising a certain number of first ramps, which are distributed on the circumference with respect to the axis of rotation, a second system of ramps comprising a corresponding number of second ramps, which are distributed correspondingly on the circumference, and the at least one ball, which respectively couples the first and second ramps, is called a ball ramp system.

The spring device preferably comprises at least one leaf spring, the number of leaf springs corresponds in particular to the number of second ramps. The design of the spring device by means of one or more leaf springs is space-saving in the direction of the axis of rotation, so only a small space is sufficient for the installation of the spring device.

Additionally, a clutch is offered with a clutch disc as offered. The clutch is a friction clutch and comprises, in addition to the clutch disc, a pressure plate, a counter-pressure plate, which can be formed in one piece with a flywheel of an internal combustion engine , for example, as well as a release mechanism for engaging and disengaging the friction clutch. The clutch is preferably operated manually. The clutch can preferably be used in a motor vehicle equipped with a hybrid powertrain.

Furthermore, there is provided a motor vehicle comprising a clutch as described herein, in which the clutch disc can be frictionally coupled to an internal combustion engine and the clutch disc is coupled to an input shaft of gearbox via the hub.

The motor vehicle preferably comprises a hybrid drivetrain, that is to say that it further comprises at least one electric motor to provide torque.

The clutch disc clutch as described in the present description allows the motor vehicle in particular to operate in freewheeling mode or in a fully electric mode.

To avoid any ambiguity, it should be noted that the words used such as "first", "second" in the present invention serve mainly (only) to distinguish several similar objects, quantities or processes, and that they therefore do not impose dependence and/or order between these objects, quantities or processes. Any necessary dependencies and/or order would be explicitly indicated here or would be obvious to those skilled in the art when studying the concretely described embodiment.

The invention and the technical environment are explained in more detail below using the figures. It should be noted that the invention cannot be limited by the examples of embodiment represented. In particular, unless explicitly stated otherwise, it is also possible to extract certain aspects of the facts explained in the figures and combine them with other components and findings of the present description and/or the figures. In particular, it should be noted that the figures and in particular the proportions indicated are only schematic. Identical references designate the same objects, so that explanations from other figures can be used in addition if necessary. On the drawings:

longitudinal section of part of a friction clutch;

longitudinal section through another part of the friction clutch; And

schematic representation of a motor vehicle.

There gives a schematic representation of a longitudinal section of a part of a friction clutch 1. The friction clutch 1 comprises a clutch disc 2 provided with a circular friction lining 3 which is coupled integrally in rotation to a disc flange 4 and an outer disc carrier 5. The friction clutch 1 has an axis of rotation 6 around which the clutch disc 2 can rotate synchronously with the outer disc carrier 5 and the outer discs 7 fixed to the latter by complementarity of form.

The clutch disc 2 further comprises a freewheel device 8 which is mounted on a hub 10 via a radial bearing 9. An inner disc carrier 11, to which the inner discs 12 are fixed by complementarity of shape, is coupled integrally in rotation to the hub 10. The interior disks 12 and the exterior disks 7 are arranged alternately in the direction of the axis of rotation 6 so as to be brought into connection by friction by a relative movement one by relative to the others in the direction of the axis of rotation 6 or to release an existing friction connection.

The freewheel device 8 comprises two ramp systems which correspond to each other. A first ramp system 13 comprises at least a first ramp 14, while a second ramp system 15 comprises at least a second ramp 16. Each first ramp 14 corresponds to a second ramp 16, the ramps 13, 14 being able to rotate one relative to the other around the axis of rotation 6 without the aid of any ball 17. In this case, the first ramp 14 is designed so as to be able to rotate by bearing on the disc flange 4 via an axial bearing 18. The second ramp 16 can come to bear in the direction of actuation 21 on an inner disc 12 which is coupled by complementarity of shape to the inner disc holder 11. A rotation of the first ramp 14 causes a movement of the second ramp 16 in the direction of actuation 21 so that the outermost inner disc 11 moves in the direction of actuation 21 which leads to the tightening of the outer discs 7 and the inner discs 12.

Furthermore, the freewheel device 8 comprises a spring device 19 which comprises at least one leaf spring 20 which is coupled to the second ramp system 15 on the one hand and to the disc flange 4 on the other hand and provides a restoring force for the second ramp system 15. The spring device 19 thus comprises at least one tension spring. When the second ramp system 15 is moved in an actuation direction 21, the spring device 19 acts in a direction opposite to the actuation direction 21. Preferably, the number of leaf springs 20 of the spring device 19 corresponds to the number of second ramps 16 in the second ramp system 15, so that a leaf spring 20 is coupled to each second ramp 16 of the second ramp system 15.

The friction clutch 1 is preferably installed in the drive train of a motor vehicle, a releasable connection to an internal combustion engine being made by the friction lining 3, while a gearbox input shaft of a gearbox is coupled by the hub 10. The freewheel device 8 described in the present description is used to allow freewheeling in a hybrid drive train. Freewheeling is achieved when the input shaft of the gearbox rotates faster than the crankshaft of the internal combustion engine and therefore than the friction lining 3. This operation is generally called deceleration speed when the gearbox input shaft rotates the internal combustion engine via the friction clutch 1 without it being supplied with fuel. The internal combustion engine serves as an engine brake. When coasting, in this state, the internal combustion engine must be decoupled from the gearbox input shaft and the internal combustion engine must operate at idle. In engine braking mode, that is to say when the torque is transmitted from the internal combustion engine to the gearbox input shaft, the friction clutch 1 transmits the torque from the friction lining 3 to the hub 10.

The freewheel device 8 is actuated via a control freewheel 22. The latter is formed in the radial direction between the hub 10 and the first ramp system 13. The disc flange 4 rests on the free control wheel 22 via a plain bearing 23. The free wheel of control 22 is designed so that, in engine braking mode, that is to say when the friction lining 3 turns faster than the hub 10, the free control wheel 22 turns in a locking direction and transmits the torque to the first ramp(s) 13 of the first ramp system 13, which thus rotates and then moves the second ramp(s) 16 of the second ramp system 15 in the actuation direction 21 and closes the frictional connection between the inner discs 12 and the outer discs 7, so that the torque can be transferred between the friction lining 3 and the hub 10 and thus between the internal combustion engine and the gearbox input shaft speed. In deceleration mode, that is to say when the friction lining 3 rotates less quickly than the hub 10, the control freewheel 22 switches to rotation in the freewheel direction, opposite to the blocking direction and the transmission of torque between the friction lining 3 and the hub 10 is interrupted. As described above, the spring device 19 causes the second ramp system 15 and the first ramp system 13 to return, the friction connection between the outer discs 7 and the inner discs 12 is released. The inner discs 12 and the outer discs 7 can be designed in a known manner as steel discs and friction discs or vice versa.

The control freewheel 22 can here be produced in a manner known per se, for example in the form of a roller freewheel, a freewheel with a locking body or a helical spring clutch. The clutch disc 2, for its part, is part of the friction clutch 1 and can be engaged and disengaged by conventional means, for example to change gear. This allows by means of a friction clutch 1 as described in the present description and also a manually operated friction clutch 1 to achieve a freewheeling function or a fully electric start in a hybrid drive train.

There shows very schematically other components of the friction clutch 1, comprising a counter-pressure plate 101, which represents, for example, a flywheel of an internal combustion engine or which can be coupled integrally in rotation to the latter, a pressure plate 103 which can be moved in an actuation direction 102 which can be actuated by a release mechanism 104, for example a release cylinder, and a clutch disc 2, which is formed in the direction of the axis of rotation 6 between the counter-pressure plate 101 and the pressure plate 103. The movement of the pressure plate 103 in the direction of actuation 102 produces or triggers a connection by friction between the counter-pressure plate pressure 101, the friction lining 3 of the clutch disc 2 and the pressure plate 103, so that a torque can be transferred between the internal combustion engine coupled to the counter pressure plate 101 and the hub not shown of the clutch disc 2.

There very schematically shows a motor vehicle 200 equipped with a hybrid drive train 201. The motor vehicle 200 comprises an internal combustion engine 202 which is coupled to a gearbox input shaft 203 of a gearbox 204 via a friction clutch 1. The rear axle 205 is driven in this case by two corresponding driving wheels 206. Furthermore, an electric motor 207 which can also provide torque to the rear axle 205 is formed. The freewheel device 4 of the friction clutch 1 makes it possible to decouple the internal combustion engine 202 from the gearbox 204 to allow for example a freewheeling mode or a fully electric driving mode, although the clutch friction 1 can be operated manually.

The clutch disc 2 described in the present description comprises a freewheel device 8 arranged radially inside with two ramp systems 13, 15 capable of rotating relative to each other, the rotation of the first system of ramps 13 causing, by means of a free control wheel 22, an axial offset of the second system of ramps 15, which causes an axial movement of the outer discs 7 and the inner discs 12 in the direction of actuation 21, so that, in engine brake speed, a torque can be transmitted between the friction lining 3 and the hub 10 via the disc block. When the free control wheel 22 interrupts, in deceleration mode, the transmission of torque, the spring device 19 causes the ramp systems 13, 15 to return backwards, and the friction connection in the disc block is released. The transmission of torque via the inner discs 12 and the outer discs 7 is thus interrupted, so that when the clutch is engaged, a freewheeling mode can be implemented, the internal combustion engine 202 - coupled to the friction lining 3 - capable of rotating independently of the gearbox input shaft 203 - coupled to the hub 10.

1. Embrayage à friction
2. Disque d’embrayage
3. Garniture de friction
4. Flasque de disque
5. Porte-disque extérieur
6. Axe de rotation
7. Disque extérieur
8. Dispositif à roue libre
9. Palier radial
10. Moyeu
11. Porte-disque intérieur
12. Disque intérieur
13. Premier système de rampes
14. Première rampe
15. Second système de rampes
16. Seconde rampe
17. Bille
18. Palier axial
19. Dispositif à ressort
20. Ressort à lames
21. Direction d’actionnement
22. Roue libre de commande
23. Palier lisse

Reference list

1. Friction clutch
2. Clutch disc
3. Friction lining
4. Disc flange
5. Outdoor disc holder
6. Rotation axis
7. Outer disk
8. Freewheel device
9. Radial bearing
10. Hub
11. Interior disc holder
12. Inner disc
13. First ramp system
14. First ramp
15. Second ramp system
16. Second ramp
17. Ball
18. Axial bearing
19. Spring device
20. Leaf spring
21. Direction of actuation
22. Freewheel control
23. Plain bearing

101 Counter pressure plate

102 Direction of actuation

103 Pressure plate

104 Release mechanism

200 Motor vehicle

201 Drivetrain

202 Internal combustion engine

203 Gearbox input shaft

204 Gearbox

205 Rear axle

206 Driving wheel

207 Electric motor

Claims (5)

Clutch disc (2) comprising a friction lining (3), a freewheel device (8) which is formed radially inside the friction lining (3) relative to an axis of rotation (6) of the clutch disc (2), a hub (10) connecting to a shaft and a disc flange (4) with which the friction lining (3) is integral in rotation,
the freewheel device (8) comprising an external disc carrier (5) coupled integrally in rotation to the disc flange (4) and an internal disc carrier (11) coupled integrally in rotation with the hub (10),
at least one outer disc (7) being coupled to the outer disc carrier (5) so as to be able to be moved by complementarity of shape and in the direction of the axis of rotation (6) and at least one inner disc (12) being coupled to the internal disc holder (11) so as to be able to be moved by complementarity of shape and in the direction of the axis of rotation (6),
the inner discs (12) and the outer discs (7) being arranged alternately in the direction of the axis of rotation (6) and capable of being brought into releasable frictional connection with each other by means of relative movement relative to each other in an actuation direction (21),
the freewheeling device (8) comprising a first ramp system (13) comprising at least a first ramp (14) and a second ramp system (15) comprising at least a second ramp (16) which is designed to correspond to a first ramp (14),
the at least one second ramp (16) can be placed on an inner disc (12) in the actuating direction (21) and is coupled to the disc flange via a spring device (19) acting in a direction opposite to the direction of actuation (21),
a control freewheel (22) being designed with a locking direction and an opposite freewheel rotation direction,
the free control wheel (22) being operatively coupled to the first ramp system (13) during rotation in the locking direction, such that rotation of the first ramp system (13) in a closing rotation direction around of the axis of rotation (6) and via the first and second corresponding ramps (14, 16) causes a movement of the second system of ramps (15) in the direction of actuation (21),
a rotation of the free control wheel (22) in the direction of free wheel rotation by the spring device causing a movement of the second ramp system (15) against the direction of actuation (21) and thus a rotation of the first ramp system (13) against the closing direction of rotation around the axis of rotation (6). Clutch disc (2) according to claim 1, in which a first ramp (14) and a second ramp (16) are respectively coupled to one another via a ball (17). Clutch disc (2) according to any one of the preceding claims, wherein the spring device (19) comprises at least one leaf spring (20). Friction clutch (1) comprising a clutch disc (2) according to any one of the preceding claims. Motor vehicle (200) comprising a clutch (1) according to claim 4, wherein the clutch disc (2) can be frictionally coupled to an internal combustion engine (202) and the clutch disc (1) is coupled to a gearbox input shaft (203) via the hub (4).