Friction clutch with self-enhancement and related power assembly

Abstract

The utility model relates to a self-reinforcing friction clutch (1) for a drive train (25) of a motor vehicle, comprising: a clutch cover (2); a pressure plate (3) displaceable in the axial direction relative to the clutch cover (2); a belleville spring (4) that acts on the axial position of the pressure plate (3); a first leaf spring unit (7) coupling the clutch cover (2) to a spring tongue (6) of the belleville spring (4); and a second leaf spring unit (8) which couples the spring tongue (6) to the pressure plate (3), the two leaf spring units (7, 8) being designed such that when the friction clutch (1) is engaged, in a traction operation of the internal combustion engine (9) rotationally coupled to the pressure plate (3) in an operating state, in addition a force which engages the friction clutch (1) acts on the spring tongue (6), and in an inertia operation of the internal combustion engine (9), in addition, a force which engages the friction clutch (1) acts on the spring tongue (6). A force that disengages the friction clutch (1) acts on the spring tongue (6), and wherein the friction clutch (1) is also designed to be normally disengaged and has a hydraulic actuating device (5) for adjusting the belleville spring (4), the actuating device drives the friction clutch (1) from its disengaged position into its engaged position by exerting pressure on the spring tongue (6) starting from a non-pressure state. The utility model also relates to a hybrid power assembly (25) with the friction clutch (1).

Description

Technical Field

[0001] The present application relates to a self-reinforcing friction clutch for a powertrain of a motor vehicle, such as a car, a truck, a bus or other commercial vehicle, the friction clutch comprising: a clutch cover; a pressure plate displaceable in an axial direction relative to the clutch cover; a disc spring acting on the axial position of the pressure plate; a first leaf spring unit coupling the clutch cover to a spring tongue of the disc spring; and a second leaf spring unit coupling the spring tongue to the pressure plate, wherein the two leaf spring units are configured such that when the friction clutch is engaged, in the traction operation of an internal combustion engine rotationally coupled to the pressure plate in the operating state, a force for engaging the friction clutch is additionally applied to the spring tongue, and in the inertia operation of the internal combustion engine, a force for disengaging the friction clutch is applied to the spring tongue. Background Art

[0002] Such a friction clutch is known, for example, from DE 10 2018 113 555 A1. A self-reinforcing friction clutch with a readjustment device is disclosed here.

[0003] However, in the embodiments known from the prior art, it has been shown that the devices for clutch actuation are relatively complex in design. For example, when using a hydraulic system, it should be noted that the centrifugal forces occurring during operation are reliably compensated, which however requires a separate compensation unit and thus requires additional structural space. Summary of the invention

[0004] It is therefore the object of the present application to provide a self-reinforcing friction clutch which is as simple and compact as possible in terms of construction.

[0005] According to the present application, this is solved in the following way: the friction clutch is also implemented as a normally disengaged one and has a hydraulic actuating device for adjusting the disc spring, wherein the actuating device is designed so that it drives the friction clutch from its disengaged position to its engaged position by applying pressure to the spring tongue starting from a pressure-free state.

[0006] By providing such a hydraulic actuation device, the friction clutch can be maintained as simply as possible, since the centrifugal force compensation unit can be omitted, since the outer diameter of the actuation device ( / slave cylinder of the actuation device) can be made smaller due to the lower engagement forces. This also allows a compact design.

[0007] Further advantageous embodiments are protected by the dependent claims and are explained in detail below.

[0008] It is therefore also advantageous if the actuating device has a slave cylinder with a piston which is arranged radially within the spring tongue and is non-movably connected to the spring tongue. This allows for a particularly space-saving arrangement of the actuating device. The actuating device is therefore preferably equipped with a slave cylinder which is designed concentrically with respect to the central axis of rotation of the friction clutch.

[0009] The actuating device remains as simple as possible in its function if the piston is guided displaceably along the axis of rotation of the pressure plate.

[0010] Therefore, it is also advantageous if the guide body of the slave cylinder that receives the piston is fastened to the clutch cover, thereby further simplifying the construction of the actuating device.

[0011] The actuating device is therefore preferably designed to rotate with the clutch cover. This keeps the actuating device as simple as possible in terms of construction. Alternatively, it is also advantageous according to another embodiment for the actuating device to be fixedly / firmly connected to a housing that is fixed to the vehicle frame and to be equipped, for example, by means of an additional release bearing between the piston and the disc spring. This in turn simplifies the hydraulic connection of the slave cylinder.

[0012] If the first leaf spring unit has at least one first leaf spring which is (only) axially connected with a first end via a connecting piece to a spring tongue, the first leaf spring unit is connected to the disc spring in a low-wear and stable manner.

[0013] If the at least one first leaf spring is mounted with its second end on the clutch cover, the first leaf spring unit can also be kept as simple as possible in terms of construction.

[0014] It is therefore also advantageous if the second leaf spring unit has at least one second leaf spring which is (only) axially connected with a first end via a connecting piece to the spring tongue.

[0015] Therefore, more preferably, at least one second leaf spring is also arranged with a second end on the pressure plate. This can also achieve a further simplification of the construction of the friction clutch.

[0016] If the connecting element has a first disk and a second disk connected to the first disk (axially fixed and rotationally fixed), wherein the spring tongue is axially (and more preferably rotationally fixed) accommodated between the first disk and the second disk, a coupling with the lowest possible wear is achieved between the spring tongue and the driven cylinder.

[0017] The disc spring can also be pivoted via a connection for displacing the pressure plate, so that a compact handling is achieved.

[0018] The pivot point about which the disk spring is pivotably received / mounted is preferably arranged radially inside or outside the pressure plate cam in contact with the disk spring, so that the installation space is used even more intensively.

[0019] The friction clutch is advantageously designed as a single-disk clutch, which further contributes to an axially compact installation space.

[0020] Furthermore, the present application relates to a hybrid drivetrain for a motor vehicle, which has a friction clutch according to the present application according to one of the embodiments described above and an electric machine operatively connected to a (second) clutch component of the friction clutch.

[0021] In other words, according to the present application, it is therefore proposed to use a friction clutch with self-enhancement as a normally open, pressed single-plate clutch, in particular as a K0 clutch for coupling an internal combustion engine to a hybrid drive and decoupling it from the hybrid drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Now, the present application is explained in detail below with reference to the accompanying drawings.

[0023] The accompanying drawings show:

[0024] Figure 1 A longitudinal section through a friction clutch according to the present application is shown according to a preferred embodiment, in which the design of the friction clutch and its coupling to the electric machine of the hybrid drivetrain can be seen, and in which the friction clutch is in a disengaged / disengaged position,

[0025] Figure 2 Show according to Figure 1 A longitudinal sectional view of a friction clutch according to the present application, wherein the friction clutch is in an engaged / closed position,

[0026] Figure 3 Show according to Figure 2 , wherein the forces acting during the coasting of the internal combustion engine connected in the operating state and increasing the separation / disengagement, and

[0027] Figure 4 Show according to Figure 2 1 , in which the forces acting in the towing mode of the internal combustion engine connected in the operating state and increasing the engagement / closing are now plotted.

[0028] The drawings are only schematic and are only useful for understanding the present application. Identical elements are provided with the same reference numerals. DETAILED DESCRIPTION

[0029] exist Figure 1, the structure of the friction clutch 1 according to the present application is shown in FIG. 1 . As explained in more detail below, the friction clutch 1 is designed as a self-reinforcing friction clutch 1. The friction clutch 1 is implemented as a single-disk clutch, i.e., is equipped with a single clutch disk 21. The friction clutch 1 is also designed as a dry-running friction clutch 1.

[0030] In addition, Figure 1 It can be seen that the friction clutch 1 is a component of a hybrid drivetrain 25 in its preferred field of use. Figure 1 The friction clutch 1 is a K0 clutch, i.e. a clutch for disconnecting or connecting the internal combustion engine 9, which is only schematically indicated in its position, from another shaft 26 of the drive train 25, such as a transmission input shaft.

[0031] The axial, radial and circumferential directions used are to be indicated with respect to the central rotation axis 19 of the friction clutch 1. Thus, the axial / axial direction is to be understood as the direction along the rotation axis 19, the radial / radial direction is to be understood as the direction perpendicular to the rotation axis 19, and the circumferential direction is to be understood as the direction along a circular line extending concentrically with the rotation axis 19.

[0032] The first clutch component 22 of the friction clutch 1 is formed in particular by a clutch disk 21. In the present exemplary embodiment, the clutch disk 21 is directly connected to an input shaft 24 which is also connected to the internal combustion engine 9 in a rotationally fixed manner.

[0033] The second clutch component 23 of the friction clutch 1 has a clutch cover 2 and a counter-pressure plate 27 connected to the clutch cover in a rotationally fixed manner. The clutch cover 2 and the counter-pressure plate 27 are firmly connected to each other at a radially outer edge 28. The clutch cover 2 extends radially inwards from the edge 28 in a substantially disk-shaped manner.

[0034] Furthermore, a pressure plate 3 , which is accommodated axially displaceably relative to the clutch cover 2 , is coupled to the clutch cover in a rotationally fixed manner. The clutch disk 21 is in turn axially located between a plate region 29 of a counter-pressure plate 27 and the pressure plate 3 .

[0035] In this embodiment variant, the second clutch component 23 is in turn connected to the shaft 26 with the interposition of a vibration damper 30 .

[0036] In addition, a disc spring 4 is provided for actuating / moving the pressure plate 3 relative to the clutch cover 2, i.e., for switching the friction clutch 1 between the disconnected / disengaged position and the closed / engaged position. The disc spring 4, which is usually used as a lever spring, rests axially on the pressure plate 3 with its outer (continuously surrounding in the circumferential direction) force edge 31, i.e., in the region of a plurality of pressure plate cams 32. A plurality of spring tongues 6, which are evenly distributed in the circumferential direction, extend radially inwardly away from the force edge 31. The disc spring 4 is usually used as an engagement element or a disengagement element for the friction clutch 1, and for generating a static pressing force for direct movement of the pressure plate 3 between the engaged position and the disengaged position.

[0037] It can also be seen that the connecting element 12 axially accommodates the entirety of the spring tongue 6, which, as explained in more detail below, is operatively connected to the actuating device 5. A first disk 15 of the connecting element 12 is arranged toward one axial side of the spring tongue 6, and a second disk 16 of the connecting element is arranged toward the other axial side of the spring tongue 6, so that the spring tongue 6 is directly supported axially between the two disks 15, 16.

[0038] exist Figure 1 The diagram in FIG. 1 illustrates the disengaged position of the friction clutch 1, while Figure 2 The engagement position of the friction clutch 1 is shown in FIG. Figure 1 As can be seen in FIG. 1 , the pressure plate 3 is arranged in a disengaged position in a manner spaced apart from the clutch disk 21 and not transmitting torque, and in Figure 2 In the engaged position, the clutch plate 21 is connected to the clutch plate 21 in a friction-locking manner.

[0039] The pressure plate 3 is coupled to the clutch cover 2 by means of two leaf spring units 7, 8, i.e., connected to the clutch cover 2 in a rotationally fixed manner and axially movable relative to the clutch cover. The first leaf spring unit 7 is a leaf spring unit that axially connects the clutch cover 2 to the spring tongue 6 via the connecting piece 12. The second leaf spring unit 8 is a leaf spring unit that axially connects the pressure plate 3 to the spring tongue 6 via the connecting piece 12.

[0040] The first leaf spring unit 7 and the second leaf spring unit 8 each have a plurality of leaf springs 10, 13 distributed in the circumferential direction, which are held in groups. In this way, a plurality of first leaf spring groups 33 uniformly distributed in the circumferential direction are provided in the first leaf spring unit 7, and a plurality of second leaf spring groups 34 uniformly distributed in the circumferential direction are provided in the second leaf spring unit 8.

[0041] Each first leaf spring 10 of the first leaf spring unit 7 is fastened with a first end 11 a to the connecting element 12 , ie, the first disk 15 of the connecting element 12 , and with a second end 11 b to the clutch cover 2 .

[0042] Each second leaf spring 13 of the second leaf spring unit 8 is fastened with a first end 14 a to the connecting element 12 , ie, the second disk 16 of the connecting element 12 , and with a second end 14 b to the pressure plate 3 .

[0043] Therefore, in the exemplary embodiment, the leaf spring units 7, 8 are indirectly (via the connecting piece 12) connected axially / in the axial direction to the spring tongue 6. The leaf spring units 7, 8 serve to preload the pressure plate 3 in the engaged position of the friction clutch 1. In addition, the leaf spring units 7, 8 achieve in the disengaged position of the friction clutch 1 that the pressure plate 3 is arranged not to transmit torque relative to the clutch disk 21.

[0044] The leaf spring units 7, 8 are used so that they are combined with the internal combustion engine 9. Figure 4 The diagram illustrates that in the traction operation (accelerating torque is transmitted via the clutch disk 21 and from there to the pressure plate 3 and the counter-pressure plate 27), the force acting on the spring tongue 6 of the disc spring 4, which engages the friction clutch 1, is increased (corresponding to the first arrow 35), and in the case of the internal combustion engine 9, the torque is increased. Figure 3 In the illustrated inertia operation (clutch disk 21 driven by clutch cover 2 and counterpressure plate 27 ), the leaf spring unit increases the force acting on spring tongue 6 of disc spring 4 for disengaging friction clutch 1 (corresponding to second arrow 36 ).

[0045] Each (first) leaf spring 10 of the first leaf spring unit 7 extends along the circumferential direction from the first end 11a toward the second end 11b. Each (second) leaf spring 13 of the second leaf spring unit 8 also extends along the first circumferential direction from the first end 14a toward the second end 14b. However, it can be seen that the first leaf spring 10 is inclined opposite to the second leaf spring 13.

[0046] It should also be noted that the leaf springs 10, 13 of the two leaf spring units 7, 8 are connected at their first ends 11a and 14a to the respective disk 15 or 16 via a rivet connection 41. The second ends 11b and 14b of the respective leaf springs 10, 13 are also connected to the clutch cover 2 or the pressure plate 3 via a rivet connection 41.

[0047] Therefore, in traction operation, the axial force generated by the leaf spring units 7, 8 acts in the same axial direction and further compresses the friction clutch 1, that is, exerts a self-reinforcing force in the engagement direction. In coasting operation, the axial force generated by the leaf spring units 7, 8 also acts in the same direction and pulls the friction clutch 1 apart, that is, disengages the friction clutch 1.

[0048] The friction clutch 1 in question is a normally disengaging clutch which also has a pressed actuating device 5 . According to the present application, the actuating device 5 is a hydraulic actuating device 5 and is designed concentrically with respect to the axis of rotation 19 .

[0049] For example, with Figure 1 It can be clearly seen that the actuating device 5 has a slave cylinder 17, which is usually connected further by means of a hydraulic control. The slave cylinder 17 has a guide body 20. The guide body 20 is firmly anchored in the clutch cover 2 and is thus connected to the clutch cover in a rotationally fixed manner / rotatably connected thereto.

[0050] The guide body 20 at least partially forms a hydraulic housing and also forms a pressure chamber 38 together with the piston 18 mounted displaceably on the guide body 20. Depending on the hydraulic pressure in the pressure chamber 38, the piston 18 can be moved between a position corresponding to the disengaged position and a position corresponding to the engaged position.

[0051] As can be clearly seen further, the piston 18 is directly connected to the connecting piece 12 in a non-displaceable manner. For this purpose, the two first and second disks 15, 16 are received / fixed radially from the outside on the sleeve region 37 of the piston 18. In other words, the piston 18 is therefore arranged radially in the disc spring 4 and is coupled axially fixedly to the spring tongue 6 via the connecting piece 12.

[0052] Therefore, in the pressure-free state of the operating device 5 ( Figure 1 ), the friction clutch 1 is in its disengaged position and the actuating device 5 is in a state in which pressure is applied relative to the pressure-free state ( Figure 1 ), the friction clutch is in its engaged position. Therefore, the friction clutch 1 is compressed by the actuating device 5 / piston 18.

[0053] In another embodiment according to the present application, the slave cylinder 17 is further connected to a housing supported in a manner fixed to the vehicle frame in a rotationally fixed manner with its guide body 20. The piston 18 is then also preferably connected to the spring tongue 6 / connecting piece 12 via a release bearing (rolling bearing).

[0054] return Figure 1 It can also be seen that in the case of the hybrid drivetrain 25, the electric machine 40 is coupled to the second clutch component 23. In particular, the rotor 39 of the electric machine 40, which is designed as an inner rotating part, is connected in a rotationally fixed manner to the counterpressure plate 27 and the clutch cover 2. The existing friction clutch 1 thus acts as a so-called separating clutch / K0 clutch.

[0055] In other words, according to the present application, a self-reinforcing clutch (friction clutch 1) is realized, in which the existing transmission ratio is used in addition to the reinforcement. The transmission is used in that the clutch is further pressed in the traction direction via the tongue (spring tongue 6) and the clutch is separated in the inertial driving direction via the tongue. The additional traction force or pressure is achieved via the principle of leaf spring reinforcement. The small reinforcement angle of the leaf springs 10, 13 is compensated by the transmission ratio of the clutch. This clamping clutch with a reinforcement system is particularly suitable for pressure regulation. For alternative stroke regulation, additional softness is provided between the separator (piston 18) and the clutch (clutch cover 2), because during the reinforcement, the tongue passes a certain stroke.

[0056] In the structural implementation, there are pressure pieces (discs 15, 16) below and above the lever spring (disc spring 4). The pressure plate 3 introduces its torque into the pressure piece (second disc 16) below the lever spring via the (second) leaf spring 13. The torque is introduced into the other pressure piece (first disc 15) via the rivet head of the first leaf spring riveted part. The pressure piece is fastened to the cover (clutch cover 2) via another leaf spring group (first leaf spring group 33).

[0057] The two pressure pieces are connected axially in the rotation center via an additional component via a detachable connection piece. The torque closure of the two pressure pieces can also be achieved via an additional component.

[0058] The leaf spring angles are selected so that they act as equally and oppositely as possible. In the traction direction, the axial forces generated by the leaf spring groups act in the same direction and further compress the clutch. In the coasting direction, the axial forces generated by the leaf spring groups act in the same direction and pull the clutch apart. In order to keep the relative strokes of the two leaf spring groups as equal as possible, it is advantageous to have the leaf springs have angles that are as equal as possible. The opposite arrangement makes it possible to keep the total stroke approximately zero. As a result, no tension is generated between the leaf springs.

[0059] Reference numerals list

[0060] 1 Friction clutch

[0061] 2 Clutch cover

[0062] 3 Pressure plate

[0063] 4 disc springs

[0064] 5 Control device

[0065] 7 First leaf spring unit

[0066] 8 Second leaf spring unit

[0067] 9 Internal combustion engine

[0068] 10 First leaf spring

[0069] 11a First end portion of the first leaf spring

[0070] 11b Second end of the first leaf spring

[0071] 12 Connectors

[0072] 13 Second leaf spring

[0073] 14a First end portion of the second leaf spring

[0074] 14b Second end portion of the second leaf spring

[0075] 15 First Plate

[0076] 16 Second set

[0077] 17 Slave Cylinder

[0078] 18 Piston

[0079] 19 Rotation axis

[0080] 20 Guide body

[0081] 21 Clutch plate

[0082] 22 First clutch component

[0083] 23 Second clutch component

[0084] 24 Input shaft

[0085] 25 Powertrain

[0086] 26 Axis

[0087] 27 Back pressure plate

[0088] 28 Edge

[0089] 29 Plate Area

[0090] 30 Shock absorber

[0091] 31 Edge of Force

[0092] 32 Platen bump

[0093] 33 First leaf spring group

[0094] 34 Second leaf spring group

[0095] 35 First Arrow

[0096] 36 Second Arrow

[0097] 37 Sleeve area

[0098] 38 Pressure chamber

[0099] 39 Rotor

[0100] 40 Motor

[0101] 41 Riveting connection device

Claims

1. A friction clutch (1) with self-enhancement, the friction clutch (1) being used for a powertrain (25) of a motor vehicle, the friction clutch comprising: a clutch cover (2); a pressure plate (3) displaceable in the axial direction relative to the clutch cover (2); a disc spring (4) acting on the axial position of the pressure plate (3); a first leaf spring unit (7) coupling the clutch cover (2) to a spring tongue (6) of the disc spring (4); and a spring tongue (6) A second leaf spring unit (8) coupled to the pressure plate (3), wherein the two leaf spring units (7, 8) are configured so that when the friction clutch (1) is engaged, in the traction operation of an internal combustion engine (9) rotationally coupled to the pressure plate (3) in the operating state, a force for engaging the friction clutch (1) is additionally applied to the spring tongue (6), and in the inertia operation of the internal combustion engine (9), a force for disengaging the friction clutch (1) is applied to the spring tongue (6), characterized in that: The friction clutch (1) is also realized as normally disengaged and has a hydraulic actuating device (5) for adjusting the disc spring (4), wherein the actuating device (5) is designed so that it drives the friction clutch (1) from its disengaged position to its engaged position by applying pressure to the spring tongue (6) starting from a pressure-free state.

2. The friction clutch (1) according to claim 1, characterized in that: The actuating device (5) has a slave cylinder (17) having a piston (18) which is arranged radially within the spring tongue (6) and is connected to the spring tongue (6) in a non-displaceable manner.

3. The friction clutch (1) according to claim 1 or 2, characterized in that: The piston (18) is guided displaceably along an axis of rotation (19) of the pressure plate (3).

4. The friction clutch (1) according to claim 2 or 3, characterized in that: The guide body (20) of the slave cylinder (17) accommodating the piston (18) is fastened to the clutch cover (2).

5. The friction clutch (1) according to any one of claims 1 to 4, characterized in that: The first leaf spring unit (7) has at least one first leaf spring (10), which is axially connected with a first end (11a) to the spring tongue (6) via a connecting piece (12).

6. The friction clutch (1) according to claim 5, characterized in that: The at least one first leaf spring (10) is attached with a second end (11b) to the clutch cover (2).

7. The friction clutch (1) according to claim 5 or 6, characterized in that: The connecting element (12) has a first disk (15) and a second disk (16) connected to the first disk (15), wherein the spring tongue (6) is axially accommodated between the first disk (15) and the second disk (16).

8. The friction clutch (1) according to any one of claims 1 to 7, characterized in that: The second leaf spring unit (8) has at least one second leaf spring (13), which is axially connected with a first end (14a) to the spring tongue (6) via the connecting piece (12).

9. The friction clutch (1) according to claim 8, characterized in that The at least one second leaf spring (13) is attached with a second end (14b) to the pressure plate (3).

10. A hybrid powertrain (25) for a motor vehicle, characterized in that The hybrid drivetrain comprises a friction clutch (1) according to any one of claims 1 to 9 and an electric machine (40) operatively connected to a clutch component (23) of the friction clutch (1).

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