Friction disc for a friction clutch

Abstract

Friction disc (1) for a friction clutch (2) of a motor vehicle (3), comprising at least the following components: - a drive disc (4) with a rotation axis (5) which can be connected to an output shaft (6) in a rotationally fixed manner; and - a spring element (7) which is designed to receive a friction lining (8) for the frictional transmission of a torque and is attached radially on the outside of the driven disc (4) by means of at least one segment foot (9), wherein the drive disc (4) and the spring element (7) are riveted together, wherein the drive disc (4) has at least one support projection (10) which is positively engaged in a support receptacle (11) of the spring element (7), characterized in that at least one of the support projections (10) is conically shaped, wherein the support receptacle (11) corresponding to the conically shaped support projection (10) has a correspondingly inclined inner receiving surface (14) and a relief cut (15) facing the drive disc (4), wherein the spring element (7) is axially spaced from the drive disc (4) by means of the conical support projection (10) at least in a pre-assembly state and the conical support projection (10) is elastically or plastically pressed together with the corresponding support receptacle (11) by means of the adjacent rivet (13).

Description

[0001] The invention relates to a friction disc for a friction clutch, a friction clutch with at least one such friction disc, a drive train with such a friction clutch, and a motor vehicle with such a drive train.

[0002] Friction discs are known from the prior art, in which a drive plate, also referred to as a clutch disc, is connected to a friction lining, usually on the outer circumference, by means of a spring lining. The spring lining is connected circumferentially to the drive plate by a single circumferential spring plate or by a plurality of individual spring segments. Such a conventional friction disc is used, for example, in the Fig. 1. A corresponding conventional spring segment is shown in Fig. 2. The conventional spring segment 30 with the friction lining 8 is connected by means of at least two rivet receptacles 31 in a conventional segment base 32 to the conventional drive plate 29, each correspondingly by means of two rivets 13. The disadvantage of this embodiment is that a large number of rivets 13 and thus a high expenditure of time are required for the assembly of the conventional friction plate 29. However, at least two rivets 13 are necessary per conventional spring segment 30 in order to prevent the conventional spring segments 30 from tilting and thus a tensile load or a shear load and / or a torsional moment being induced in the radial direction on the friction lining 8 as a result of a torque input about the rotation axis 5 onto the friction surface of the conventional friction plate 29. This would disrupt the frictional connection and reduce the transmittable torque or even destroy the friction lining 8.

[0003] Furthermore, a friction disc is known from DE 44 09 253 A1, which can be read in the preamble of claim 1.

[0004] The present invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features of the invention arise from the independent claim, for which an advantageous embodiment is presented in the dependent claim. The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures, which comprise additional embodiments of the invention, can also be considered.

[0005] The invention relates to a friction disc for a friction clutch of a motor vehicle, comprising at least the following components: - a drive plate with a rotation axis, which can be connected to an output shaft in a rotationally fixed manner; and - a spring element which is designed to receive a friction lining for the frictional transmission of a torque and is fastened radially on the outside to the driving plate by means of at least one segment foot, wherein the driving plate and the spring element are riveted to one another.

[0006] The friction disc is characterized in particular in that the drive disc has at least one support elevation which is positively received in a support receptacle of the spring element.

[0007] The friction disc proposed here is designed to reduce the number of rivets required. For this purpose, at least one support elevation is provided on the drive plate, which, instead of a rivet, provides appropriate support for the spring element in conjunction with the corresponding support receptacle. It should be noted that the spring element further comprises at least one rivet, preferably a plurality of rivets distributed over the circumference of the drive plate, wherein the spring element and the drive plate are firmly connected to one another in the axial direction relative to the axis of rotation of the friction disc by means of the at least one rivet. Thus, in accordance with the second function of the rivet, the support elevation only absorbs forces transverse to the support elevation, i.e. also transverse to the rivet.

[0008] Preferably, the support protrusion is formed integrally with the drive plate by means of stamping, deep drawing, upsetting, punching, or similar cold forming from the sheet metal material of the blank. Particularly preferably, the support protrusion is created in a joint forming step of the drive plate, so that no additional work step is required to create the support protrusion. Accordingly, the support receptacle of the spring element, or the majority of the support receptacles of the spring element, is preferably manufactured in the same way as a conventional rivet receptacle, without an additional work step.

[0009] However, the support mount is particularly preferably manufactured by punching, whereby the fit of the support mount is adapted to the shape of the support projection and thus the slave plate. Thus, using a simple manufacturing process, preferably in a single production step, the spring element or several spring elements together with the support mount are produced from a single sheet material. This allows the support projection to be produced at low cost, and the support mount can be manufactured with little additional cost or even at zero cost. As a result of the reduction in assembly steps due to the reduced number of rivets, any additional costs are offset or the overall manufacturing costs are reduced.

[0010] In a further advantageous embodiment of the friction disc, the spring element is divided into a plurality of spring segments and each spring segment is secured against tilting to the drive disc by means of a single rivet and at least one of the support elevations, preferably two of the support elevations.

[0011] In this preferred embodiment, the spring element for connecting the friction lining to the drive plate is divided into a plurality of spring segments, each of which forms individual components. The individual spring segments are preferably structurally identical, thereby reducing the number of identical components and thus reducing manufacturing costs. Each spring segment can be axially connected to the drive plate by means of a single rivet and is secured against rotation around the single rivet by means of the support receptacle, preferably two support receptacles, and the corresponding support elevation(s), i.e., the two support elevations, to the drive plate in a manner that prevents it from tilting. This prevents shear loads from occurring on the rivet.

[0012] In a particularly preferred embodiment, the transverse load on the rivet is reduced in such a way that the rivet to be used can be dimensioned smaller and consequently the material costs are reduced.

[0013] According to the invention, at least one of the support elevations is conically shaped.

[0014] Accordingly, the support protrusion is designed to facilitate pre-assembly of the spring element on the support protrusions by providing undersize, i.e., clearance. After the spring element is attached to the drive plate, the diameter widens in the axial direction toward the drive plate, allowing it to fit precisely with little or no clearance on the surface of the drive plate. Such a support protrusion thus facilitates production by allowing the spring element to be positioned during pre-assembly without the need for riveting.

[0015] Further according to the invention, the support receptacle corresponding to the conically shaped support elevation has a correspondingly inclined inner receiving surface and a free cut facing the drive plate.

[0016] Accordingly, the inner receptacle is negatively conical in shape, i.e., it has an inclined inner receiving surface, which is preferably formed with a closed, circumferential shape. Firstly, this inclined inner receiving surface facilitates the (pre-)assembly of the spring element. Secondly, in the assembled state, i.e., when the (adjacent) rivet is in place, the contact area between the support elevation and the support receptacle is enlarged by the inclined inner receiving surface resting precisely on the support elevation.

[0017] Accordingly, a clearance cut, such as a chamfer or a radius, is provided on the side of the spring element facing the drive plate in the support recess. This reliably prevents a collision between the transition from the contact surface of the drive plate to the support elevation, which is formed radially, for example. Furthermore, a secure contact of the inclined inner receiving surface with the conically shaped support elevation is ensured.

[0018] Particularly preferably, the spring element can be brought into contact with a contact surface of the drive plate, i.e., the surface surrounding the support elevation or an (indirectly) adjacent surface. This creates an additional frictional connection between the spring element and the drive plate, so that, as a result of this frictional connection, an additional support moment is ensured to prevent the spring element or a spring segment from tilting.

[0019] According to the invention, the spring element is axially spaced from the drive plate by means of the conical support elevation, at least in a pre-assembly state, and the conical support elevation is elastically or plastically pressed with the corresponding support receptacle by means of the adjacent rivet.

[0020] Accordingly, the strength of the connection between the support elevation and the support receptacle is increased by pressing the spring element towards the drive plate by means of the adjacent rivet. Due to an oversize relative to the mounting position, i.e., the set axial distance between the spring element and the drive plate, a press fit is created between the support elevation and the support receptacle. The corresponding support receptacle is thereby elastically and preferably plastically deformed, thus forming a frictional connection beyond the positive connection between the support receptacle and the support elevation. This further reduces the load on the rivet or even eliminates transverse loading and thus shear loading of the adjacent rivet.

[0021] The adjacent rivet is the only rivet in a spring segment. In a spring element with a plurality of rivets, it is the rivet which is arranged closest in the circumferential direction to the support elevation. Preferably, the adjacent rivet is no further away from the support elevation than the two rivets are apart in a conventional design of the friction disc. For example, the angular distance relative to the axis of rotation in the circumferential direction is less than 15° [degrees], preferably less than 10°, particularly preferably less than 5°. Alternatively, the circumferential length distance between the centers of the rivet receptacle and an adjacent support receptacle is less than 50 mm [millimeters], preferably less than 30 mm, particularly preferably less than 25 mm. However, for a good leverage effect, a distance of at least 5 mm [millimeters], preferably at least 10 mm is advantageous.

[0022] According to a further aspect of the invention, a friction clutch with a rotational axis for a drive train is proposed, wherein the friction clutch has at least the following components: - an input shaft; - an output shaft; - a compressible friction package for transmitting torque between the input shaft and the output shaft in the compressed state, wherein the friction package comprises a counter plate, at least one pressure plate and a corresponding number of friction discs according to an embodiment according to the above description, wherein preferably the at least one support elevation faces the counter plate.

[0023] The friction clutch is designed to releasably transmit torque from an output shaft to a consumer and vice versa. This is generally achieved via the (at least one) friction assembly, which, according to one embodiment, has an axially displaceable pressure plate, generally rotationally fixed to the output shaft, which can be pressed against at least one corresponding friction disc. In another embodiment, the friction assembly is formed by a plurality of friction discs. In the friction disc assembly, friction discs and pressure plates are provided alternately. This friction disc assembly is displaceably suspended in such a way that the friction discs and pressure plates can be pressed together and, with each contact surface between the friction discs and the pressure plates and the counterplate, form a cumulative total friction surface.As a result of a contact force, a friction force is generated across the (total) friction surface, which, when multiplied by the average radius of the (total) friction surface, results in a transmittable torque.

[0024] The friction clutch proposed here is balanced along its rotational axis. In the following, reference will be made to this rotational axis when referring to the axial direction, radial direction, or circumferential direction.

[0025] The friction clutch can be integrated into a drive train, allowing torque to be shiftably transferred from the input shaft to the output shaft and vice versa, for example, during overrun. In many cases, the input shaft is at least indirectly connected to an output shaft or formed integrally, and the output shaft is at least indirectly connected to a consumer.

[0026] In a preferred embodiment, at least one of the two shafts, preferably the output shaft, is rigidly connected to a manual transmission. The manual transmission is configured to allow a different torque ratio to be set. Preferably, shifting the manual transmission, i.e., changing the gear ratio, is only possible when the friction clutch is open, i.e., when the friction pack is not compressed, so that no opposing torques are applied to the manual transmission during a shifting operation.

[0027] The friction clutch can be manufactured more cost-effectively, more quickly and in a space-neutral manner with at least one friction disc according to an embodiment as described above.

[0028] According to a further aspect of the invention, a drive train is proposed which has a drive unit with an output shaft, at least one consumer and a friction clutch according to the above description, wherein the output shaft is detachably connected to the at least one consumer by means of the friction clutch for torque transmission.

[0029] The drive train is designed to releasably transmit, i.e., connectable and disconnectable, a torque provided by a drive unit, for example, an energy conversion machine, preferably an internal combustion engine or an electric drive unit, and output via its output shaft to at least one consumer. An exemplary consumer is at least one drive wheel of a motor vehicle and / or an electric generator for providing electrical energy. Conversely, the absorption of inertial energy introduced, for example, by a drive wheel is also feasible. The at least one drive wheel then forms the drive unit, wherein its inertial energy can be transferred by means of the friction clutch to an electric generator for recuperation, i.e., for electrically storing the braking energy, with a correspondingly configured drive train.Furthermore, in a preferred embodiment, a plurality of drive units are provided, which can be operated in series or parallel or decoupled from one another by means of the friction clutch, or whose torque can be detachably made available for use. Examples include hybrid drives consisting of an electric drive motor and an internal combustion engine, but also multi-cylinder engines in which individual cylinders (groups) can be switched on.

[0030] In order to transmit torque in a targeted manner and / or via a manual transmission with different gear ratios, or to disengage a transmission, the use of the friction clutch described above is particularly advantageous. The drivetrain proposed here comprises a friction clutch comprising at least one cost-effectively manufactured friction disc that meets the highest requirements of a drivetrain and can be used in a space-neutral manner.

[0031] According to a further aspect of the invention, a motor vehicle is proposed which has at least one drive wheel which can be driven by means of a drive train according to the above description.

[0032] Most motor vehicles today have front-wheel drive, and therefore the drive unit, such as an internal combustion engine or an electric drive unit, is preferably positioned in front of the driver's cab and perpendicular to the main direction of travel. The installation space is particularly limited with such an arrangement, making it particularly advantageous to use a small friction clutch. The use of a friction clutch in motorcycles is similar, requiring significantly increased performance while maintaining the same installation space.

[0033] This problem is exacerbated in small-car passenger cars according to the European classification. The functional units used in a small-car passenger car are not significantly smaller than in larger passenger cars. Nevertheless, the available installation space is considerably smaller in small cars. The drivetrain described above features a cost-effective friction clutch with a consistently small size, with at least one friction disc being manufactured more quickly and cost-effectively.

[0034] Passenger cars are assigned to a vehicle class based on factors such as size, price, weight, and performance, although this definition is subject to constant change according to market needs. In the US market, vehicles in the small car and subcompact car classes are classified as subcompact cars according to the European classification, while in the British market they correspond to the supermini and city car classes, respectively. Examples of the subcompact car class include a Volkswagen up! or a Renault Twingo. Examples of the compact car class include an Alfa Romeo Mito, Volkswagen Polo, Ford Fiesta, or Renault Clio.

[0035] The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, whereby it should be noted that the drawings are not to scale and are not suitable for defining proportions. It is shown in Fig. 1: a conventional disc; Fig. 2: a conventional spring segment; Fig. 3: a friction disc with a reduced number of rivets; Fig. 4: a spring segment with a single rivet receptacle and two support receptacles; Fig. 5: a segment foot in section through a support holder with inclined inner receiving surface; Fig. 6: a section of a friction disc in section with a segment foot (pre-)mounted on a support elevation; Fig. 7: a section of a friction disc with a mounted spring element with a single rivet and two support elevations; Fig. 8: a friction clutch with a friction disc, in which the spring element is connected to the drive disc facing the pressure plate; Fig. 9: a friction clutch with a friction disc, in which the spring element is connected to the drive disc facing the counter plate; and Fig. 10: a drive train in a motor vehicle with a friction clutch.

[0036] In Fig. 1 shows a conventional friction disc 28 in which a friction lining 8 is connected to a conventional drive disc 29 with a rotation axis 5 by means of a plurality of conventional spring segments 30, each by means of two rivets 13.

[0037] In Fig. 2 shows such a conventional spring segment 30, which has a conventional segment foot 32 with two rivet receptacles 31.

[0038] In Fig. 3 shows a friction disc 1 with a drive plate 4, which is rotatable about a rotation axis 5 and is preferably rotationally symmetrical to the rotation axis 5. The friction lining 8 is connected to the drive plate 4 by means of a spring element 7. For this purpose, the spring element 7 has a plurality of segment feet 9, each of which is connected to the drive plate 4 by means of a single rivet 13 and here two of the support elevations 10 in a tilt-proof manner. The spring element 7 is formed in one piece or in several pieces, for example from a plurality of spring segments 12, like one in Fig. 4 is shown.

[0039] In Fig. 4 shows a single spring segment 12, which forms a spring element 7 with further preferably identical spring segments 12, for example as in Fig. 3. The spring segment 12 has a segment foot 9 which has three openings, of which the middle one is a rivet receptacle 31 and the two outer ones form the adjacent support receptacles 11.

[0040] In Fig. 5 is a section of a segment foot 9, for example according to the marking in Fig. 4, a section through a support receptacle 11 in a preferred embodiment is shown. The support receptacle 11 has an inclined inner receiving surface 14, which corresponds to a conical support elevation 10 (see Fig. 6). Furthermore, the support receptacle 11 shown here has an (optional) cutout 15, which is designed here as a chamfer.

[0041] In Fig. 6 shows a section of a friction disc 1, wherein the segment base 9 of the spring element 7 is shown in section (pre-) mounted on a drive plate 4 and a friction lining 8 is shown. The sectioned support receptacle 11 corresponds to the illustration in Fig. 5 and the support elevation 10 is conical. Thus, the support receptacle can be easily guided onto the support elevation 10 and at the same time a secure fit for a rigid connection between the support receptacle 11 and the support elevation 10 is formed. In the embodiment shown here, the segment foot 9 is slightly spaced from the contact surface of the drive plate 4. This is a pre-assembly state, wherein the distance is reduced or eliminated, or a final state. Preferably, the support receptacle 11 is fastened to the support elevation 10 by means of the adjacent rivet 13 (see Fig. 7) pressed axially.

[0042] In Fig. 7 shows a section of a friction disc 1, in which the segment base 9 of a spring element 7, of which a section of a friction lining 8 can be seen, is firmly connected to a drive plate 4 by means of a rivet 13. The two adjacent support elevations 10 reduce the shear load on the rivet 13 in conjunction with the precisely fitted support receptacles 11, so that the spring element 7 or the segment base 9 is connected to the drive plate 4 in a tilt-proof manner. The support receptacles 11 are preferably pressed onto the support elevations 10 by means of the adjacent rivet 13, preferably by means of the single rivet 13 of a spring segment 12 (cf. Fig. 4).

[0043] In Fig. 8 shows a simple friction clutch 2 in section, wherein on the left in the illustration there is a counter plate 19, on the right in the illustration there is a drive plate 20 and between the counter plate 19 and the application plate 20 there is a single friction disc 1, which together form a friction assembly 18. By means of axial movement of the address plate 20 towards the counter plate 19, the friction assembly 18 is pressed. This allows a torque about the axis of rotation 5 to be releasably transmitted to the output shaft 6 (only the corresponding shaft connection is shown here). The friction disc 1 has a drive plate 4 and a friction lining 8 (on both sides), wherein the friction lining 8 is connected to the drive plate 4 by means of a spring element 7 by means of a reduced number of rivets 13. The spring element 7 is arranged on the pressure plate side of the drive plate 4.

[0044] In Fig. 9 shows a similar configuration of a friction clutch 2. Therefore, for identical components with identical reference numerals, reference is made to the description of Fig. 8. In contrast to the embodiment of the friction clutch 2 in Fig. 8, the spring element 7 is arranged on the counter-plate side of the drive plate 4. This is advantageous if the spring element 7 is pulled axially when the drive plate 20 is released, because then in this configuration the spring element 7 is pulled towards the drive plate 4. Thus, the axial connection between the support elevation 10 and the support receptacle 11 (see Fig. 7) is tightened instead of loosened. It should be noted, however, that such axial pulling of the spring element 7 does not occur in every friction clutch. The different arrangement of the spring element 7 relative to the drive plate 4 is generally irrelevant for the installation space.

[0045] In Fig.10 schematically shows a drive train 16 comprising a drive unit 21, depicted here as an internal combustion engine, an output shaft 22, a friction clutch 2, and a torque-transmitting left drive wheel 23 and right drive wheel 24. The drive train 16 is arranged in a motor vehicle 3, with the drive unit 21 arranged with its engine axis 27 transverse to the longitudinal axis 26 in front of the driver's cab 25.

[0046] With the friction disc proposed here, assembly effort is reduced and thus a friction disc can be manufactured more cost-effectively. List of reference symbols 1 friction disc 2 friction clutch 3 Motor vehicle 4 drive plate 5 Rotation axis 6 Output shaft 7 Spring element 8 Friction lining 9 Segment foot 10 Support elevation 11 Support mount 12 spring segments 13 rivets 14 Interior recording area 15 free cut 16 Powertrain 17 Input shaft 18 friction package 19 Counter plate 20 pressure plate 21 Drive unit 22 Output shaft 23 left drive wheel 24 right drive wheel 25 Driver's cab 26 Longitudinal axis 27 Motor axle 28 conventional friction disc 29 conventional drive plate 30 conventional spring segment 31 rivet holder 32 conventional segment foot

Claims

[1] Friction disc (1) for a friction clutch (2) of a motor vehicle (3), comprising at least the following components: - a drive plate (4) with a rotation axis (5) which can be connected in a rotationally fixed manner to an output shaft (6); and - a spring element (7) which is designed to receive a friction lining (8) for the frictional transmission of a torque and is fastened radially on the outside to the drive plate (4) by means of at least one segment foot (9), wherein the drive plate (4) and the spring element (7) are riveted together, wherein the drive plate (4) has at least one support elevation (10) which is positively received in a support receptacle (11) of the spring element (7), characterized by , that at least one of the support elevations (10) is conically shaped, wherein the support receptacle (11) corresponding to the conically shaped support elevation (10) has a correspondingly inclined inner receiving surface (14) and a free cut (15) facing the drive plate (4), wherein the spring element (7) is axially spaced from the drive plate (4) by means of the conical support elevation (10) at least in a pre-assembly state and the conical support elevation (10) is elastically or plastically pressed with the corresponding support receptacle (11) by means of the adjacent rivet (13). [2] Friction disc (1) according to claim 1, wherein the spring element (7) is divided into a plurality of spring segments (12) and each spring segment (12) is secured against tilting to the drive disc (4) by means of a single rivet (13) and at least one of the support elevations (10), preferably two of the support elevations (10).

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