WO2019120373A1

WO2019120373A1 - Friction plate for axial pressing with a friction partner

Info

Publication number: WO2019120373A1
Application number: PCT/DE2018/100960
Authority: WO
Inventors: Ivo Agner
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2017-12-20
Filing date: 2018-11-27
Publication date: 2019-06-27
Also published as: DE102018100803A1

Abstract

The invention relates to a friction plate (1, 2) for axial pressing with a friction partner (40, 41) for frictionally transferring a torque about an axis of rotation (3), wherein: the friction surface (4, 5, 6, 7) has a plurality of grooves (10); the grooves (10) run in the circumferential direction (12, 13) and each has a groove width (14); the friction surface (4, 5, 6, 7) has at least one lifting curve (15) with a continuous course (16) over at least 90° in the circumferential direction (12, 13); the lifting curve (15) extends axially from the friction surface (4, 5, 6, 7) and is pointed in the axial direction (17); the lifting curve (15) has a course radius (18) relative to the axis of rotation (3); the lifting curve (15) has a radius change (19, 20) over its course (16) in the circumferential direction (12, 13); and the lifting curve (15) has a maximum point (21, 22) with a maximum radius (23) and a minimum point (24, 25) with a minimum radius (26). The friction plate (1, 2) is characterised in particular in that the course radius (18) has such a radius change (19, 20) that the maximum radius (23) is greater than the minimum radius (26) by at least 1.5 times the groove width (14). A good damping property is achieved by the friction plate proposed here with a pointed lifting curve, and at the same time the formation of circumferential grooves is avoided.

Description

Friction plate for axial compression with a friction partner

The invention relates to a friction plate for axial compression with a friction partner for the frictional transmission of torque about an axis of rotation, wherein the friction surface has a plurality of grooves, wherein the grooves extend in the circumferential direction and each have a groove width, and

wherein the friction surface at least one elevation curve with a in

Circumferential direction has a continuous course over at least 90 °, wherein the elevation curve extends axially out of the friction surface and is pointed in the axial direction, wherein the elevation curve has a radius of curvature to the axis of rotation, wherein the elevation curve in its course in

Circulation direction has a change in radius, wherein the elevation curve has a maximum point with a maximum radius and a minimum point with a

Minimal radius has. The friction plate is mainly characterized in that the radius of curvature has a change in radius such that the maximum radius is greater by at least 1.5 times the groove width than the minimum radius.

From the prior art friction plates are for use in one

Friction clutch, known as a disc brake. Here is a solvable

Torque transmission, for example, a crankshaft one

Internal combustion engine or to decelerate a motor vehicle, frictionally enabled as a result of axial compression. The friction pair formed for this purpose comprises at least one friction plate and at least one friction partner, for example a friction disk or one or more brake pads. The friction plate is the harder friction surface, which is the softer

Counter friction surface of the friction partner, often a (preferably replaceable) friction lining, wear more than the friction surface itself wears. The

Gegenreibfläche is made of a variety of materials, for example

Plastics, ceramics or sintered metals, and includes some fiber reinforcement and / or particle additives. The friction surface of Gussanpressplatten of friction clutches is preferably made by means of the cutting method turning. Here, the friction surface is machined over the entire surface width used for the frictional engagement. Using a conventional indexable insert results in a

Friction surface with rounded Rillentälern and (nearly) pointed elevations, which line up in the radial direction, that are immediately adjacent to each other. The elevations are pointedly dependent on the shape of the indexable insert, so for example, the rounding radius, also the distance, ie the relative position of the valleys to each other and the material behavior. The material behavior affects the shape of the survey in the way that if the material is very tough, for example, burr-like peaks are formed, and that if the material is very brittle, uneven fracture edges can be formed. In Fig. 2 and in Fig. 3 are exemplary illustrated some form of writing such grooves, in which case the

For example, a groove width is 0.3 mm [three tenths of a millimeter] and a groove depth is 20 pm [twenty microns], for example, so a groove depth to groove width ratio is more likely to be 1:10 to settle to 1:50.

The distance between the resulting contours of the grooves is determined by the

Feed (/) set. The feed is here the amount of radial movement of the indexable insert per revolution of the workpiece. The feeds range in ranges up to 0.6 mm [six tenths of a millimeter] and the resulting depth of the groove valleys in ranges up to 40 pm [forty microns]. The groove resulting from the turning process therefore has a spiral shape which depends on the direction of rotation of the

Workpiece and the direction of the feed, from the inside out or

vice versa, is determined. Fig. 4 shows a clearly exaggerated representation of such (ideal, ie mathematical) spiral shape.

When manufacturing with CNC (English: Computerized Numerical Control) machines usually no mathematical spiral is realized, but it creates a concentric contour over a certain angular range and over the following angular range of the feed is realized. The reason is due to the fact that the two control tasks, first with changing radius the Tracking cutting speed and keep constant and secondly the

Realization of the feed, to be executed digitally one after the other. This leads approximately to the spiral shape as shown in Fig. 5.

The friction surface of the friction plate described above works in the friction partner in the form of circumferential grooves. This creates concentric, ie non-spiral, surface structures in the friction lining. A third order of the ripple of the friction surface and small offsets between pressure plate and center of rotation coupling, which can produce large rotation angle ranges with almost invariable radii not only in a CNC spiral, but also in a mathematically ideal spiral are causes for circumferential grooves in the lining already during the running-in process , This is shown in FIG.

These circumferential grooves in the friction partner cause a radial toothing of the

Friction disc with the friction plate. In, for example, mobile applications,

For example, in a motor vehicle, radial vibrations of the

friction plate-side shaft, for example, the transmission shaft in a friction clutch, with axial vibrations and tilting vibrations of the friction plate due to this

Coupled gearing and can lead to unwanted noise emissions. Due to the contact angle, a (cutting) deformation of the counter-friction surface is generated, so that it has circumferential grooves. This results in a radial

Transferability of forces from friction plate to the friction partner and vice versa for an axial force component due to a relative radial displacement of friction plate to friction partner.

A simple remedy would be to produce with a significantly lower roughness, so less groove width and / or groove depth or blunt, for example, rounded, surveys. Due to the much flatter

Contact angle can thus be minimized the gearing effect.

However, it has been found that smooth friction surfaces have a negative effect on the so-called Rupfverhalten. The Rupfverhalten is a jerky

Torque input in the frictional engagement, which is so large that the friction plate and the friction partner again spaced from each other against the axial contact force. This creates a jolting start in the motor vehicle.

It is therefore desirable to achieve a positive damping, which is realized as a result of an increasing Reibwertgradienten on the differential speed. If this gradient is negative, self-excited torsional chattering may occur. In this context, the pointed elevations of the

Rotary contour as advantageous.

In fact, it has been shown that small abrasive particles are more tribologically effective on smooth surfaces than on rough surfaces. This is due to the fact that, although rough surfaces form grooves in the counter friction surface of the friction partner, they only almost completely fill the grooves in the casting in contact with large surface pressures due to the elasticity of the abrasive particles

(compare Figs. 2 and 3). In this respect, abrasion particles which are not tribologically effective can collect in the valleys of the valleys and, at higher surface pressures, can be removed from the grooves by means of the resulting friction with the counter friction surface

Circumferential direction can be transported or wiped.

There is thus a conflict of objectives: on the one hand a smooth surface is desirable to the coupling of radial vibrations of the friction partner with the axial

or to prevent tilting vibrations of the friction plate; On the other hand, a rough friction surface offers the possibility of collecting abrasive particles in the groove valleys, so that they can not become tribologically effective and ensure good damping behavior of the frictional contact.

Ideal would therefore be a manufacturing process, on the one hand realizes deep grooves in the friction plate and on the other hand prevents the formation of circumferential grooves in the Gegenreibfläche during operation. To achieve the damping effect is a (nearly)

It is not sufficient to merely increase the feed (clearly) in order to only partially turn a groove into the friction surface. In this case, the smooth adverse surface areas outweigh. On this basis, the present invention has the object, at least partially overcome the known from the prior art disadvantages. The features of the invention will become apparent from the independent claims, to which advantageous embodiments are indicated in the dependent claims. The features of the claims may be combined in any technically meaningful manner, and to this end, the explanations of the

following description and features of the figures can be added, which comprise additional embodiments of the invention.

The invention relates to a friction plate for axial compression with a friction partner for frictionally transmitting a torque about an axis of rotation, wherein the friction plate has at least one friction surface with a radial surface width in a plane perpendicular to the axis of rotation, and

wherein the friction surface has a plurality of grooves with a groove valley and two groove mountain flanks each adjacent to a further groove of the plurality of grooves, the grooves extending in the circumferential direction and one each

Have groove width, and

wherein the friction surface at least one elevation curve with a in

Minimal radius has.

The friction plate is mainly characterized in that the radius of curvature has a change in radius such that the maximum radius at least the

1, 5 times the groove width is greater than the minimum radius.

In the following, reference will be made to the aforementioned axis of rotation, if the axial direction, radial direction or direction are not explicitly indicated

Reverse direction and corresponding terms are used. The friction plate is as explained above for the frictional transmission of a

Torque, for example, in a friction clutch or a disc brake, set up. In a friction clutch, the friction plate forms, for example, the

Pressure plate, the counter plate or, in a double clutch, a central web. In the case of a disc brake, the brake disk axially loaded on one or both sides by means of a brake pad.

According to one embodiment, the friction plate is a cast component or a

Steel plate, preferably as a sheet metal blank. The grooves are produced by (for example surface-turning) rotation in the friction side, so that macroscopically, or in the middle, a flat friction surface is produced, to which the rotation axis is normally aligned. It should be noted here that always meaningful from technically achievable or cost pressure

tolerance-related contexts is spoken. Therefore, as a

Surface having, for example, a tilt deviation to the

Rotation axis, surface irregularities and / or not ideal centrally arranged rotation axis within a given tolerance yet as even or normal, that is perpendicular, so called. This applies equally to subsequent relationships.

Alternatively, the grooves are produced by extrusion. Especially with such

Embodiment, the shape of the grooves is arbitrary, preferably in terms of

Groove contour, the groove width and the groove depth, but also in terms of a

Groove course over the circumference of the friction plate. The grooves cover a large part of the surface width of the friction surface over the circumference, preferably, the entire friction surface is provided with grooves. On the one hand, the grooves should be suitable for absorbing abrasion particles but, on the other hand, should not have a tendency to be buried in the counter friction surface. The grooves each have, for example

rounded Rillental on which, for example, steadily, in each case a left and right edge of a groove with an inclined surface with axial portion are executed and adjacent to an adjacent groove flank of an adjacent groove. Preferably, the groove flanks merge into one another at an acute angle, as is known from the prior art. For some applications, it may be sufficient if narrow lands are formed with a flat surface of radial extent are. This is achieved, for example, when the axial feed of an indexable insert leads to a groove width which is less than half of the radial feed (over one complete revolution).

A low abrasion performance is hereby achieved by means of a survey curve, which in the direction of rotation has a continuous course over at least 90 °, preferably at least 180 °, particularly preferably over a complete circulation, ie 360 °. Continuously means in this context that the survey curve is performed without abrupt jumps in the radial direction, preferably in the direction of rotation is steadily formed. The elevation curve rises axially out of the friction surface, that is in the direction of the groove flanks. The

Survey curve is pointed in the axial direction. This means that the tip forms a (continuous) ridge in the direction of rotation, in which the flanks to the right and to the left of the ridge in each case by more than 30 ° from the friction plane to the

Return plate material, preferably by more than 45 °. The burrs are dependent on the selected material and / or the cutting speed of the

Indexable insert or other process parameters, for example, irregular, for example, such as a summit chain and or more parallel ridges, ie local maxima, formed with some very steep partial edges. According to one embodiment, the elevation curve superimposes the grooves and thus forms a separate curve on the friction surface.

The elevation curve has a radius of curvature with respect to the axis of rotation, which has a change in radius in the course of the elevation curve in the direction of rotation. It is thus at least one maximum point with a maximum radius and at least one minimum point with a minimum radius over the course of

For example, 90 ° or more provided. This change in radius is formed in such a way that the maximum radius is greater than the minimum radius by at least 1.5 times the groove width. At 1, 5 times the groove width, an installation tolerance is already taken into account, so that it is ensured that the survey curve is the location of the

Minimum point on the counter friction surface after a relative rotation around the

Angle amount of the course of the survey curve at least once migrated. This ensures that no circumferential grooves are generated in the Gegenreibfläche, because no DC components of the radius of curvature occur or only on very short Stretch. With an increase in the radius change to 2.5 times the groove width of the effect is further minimized, it has been found that thereby the DC components of the radius of curvature even with an unfavorable CNC spiral and / or with very large installation tolerances with respect to the alignment of the axis of rotation the friction plate to the axis of rotation of the friction partner, which are ideally congruent to each other, have no negative effect on the formation of circumferential grooves. With a radius change over one complete revolution to more than three times the groove width, for example, four times to six times the groove width, formation of circumferential grooves in the counter friction surface over the entire lifetime of a counter friction surface is precluded.

At most, the radius change should correspond to a complete revolution, ie 360 °, not more than 20 times the groove width. After that, no advantageous effects are achieved with respect to the prevention of the formation of circumferential grooves. In addition, the production, in particular a cutting process, difficult to handle, for example, in terms of a rotationally stable unbalanced

Clamping the plate blank and / or a feed control at a mostly material-related rotational speed when turning.

According to an advantageous embodiment of the friction plate is the elevation curve of the, preferably unsteady, transition from a groove mountain edge to the adjacent Rillenberg flank formed, preferably a plurality of radially parallel grooves with radially outwardly increasing radius of curvature, preferably concentric with the axis of rotation and / or preferred with the same groove width is formed.

According to this embodiment, the elevation curve is formed by at least two adjacent grooves. Particularly preferably, the elevation curve is formed by all groove flanks. Thus, the course of the survey curve with at least one groove, preferably all grooves, identical. How acute the elevation curve is, then depends on the respective groove flanks. According to a preferred embodiment, the elevation curve is formed as pointed, as described in the introduction conventionally generated in the introduction of grooves in a turning process under conventional feed. Deviating from this, however, the radius change of the grooves is greater than this in such conventional adjacent grooves is the case. Although this is achievable by reducing the number of revolutions of the grooves, but this leads to an undesirable blunting of the survey. How nevertheless a large radius change can be achieved is shown in the following description.

According to a preferred embodiment, a plurality of parallel grooves are formed, which run adjacent in the circumferential direction. That is, adjacent grooves are not part of a single continuous curve, but are multiple curves with their own starting point and end point. For example, such grooves are rotated with an indexable insert having a plurality of adjacent cutting edges, so that the feed corresponds to a multiple of a groove, namely the number of grooves, which are formed with a cut. In the case of a extruded surface, such a shape can also be imaged. Such grooves are concentric, so executable with the axis of rotation as the center, or with an eccentric arrangement of the center.

Irrespective of one of the above-mentioned and following embodiments, the groove width and / or groove depth is preferably constant over the entire surface width. Thus, the friction surface is inexpensive to produce, for example by means of a rotation process, and the damping behavior is approximately equal over the entire surface width.

According to an advantageous embodiment of the friction plate, the radius of curvature of the at least one elevation curve increases in the direction of rotation, preferably constant.

According to this embodiment, a spiral is formed, preferably one

mathematical spiral. This promotes the removal of abrasion particles during rotation in the direction of rotation. A corrugation or other decrease in the

Radial change in the course can lead to a retention of abrasion particles. By means of a mathematical spiral, the DC component is reduced in the course and thus already leads to a lower feed to a reduced inclination

Generating circumferential grooves in the counter friction surface. Preferably, a spiral is combined with an eccentricity, so that the center of the spiral is arranged offset to the axis of rotation. This makes it possible to carry out the groove pattern conventionally, for example by means of a rotation process and immediately adjacent grooves, wherein at the same time an increase in the radius change is achieved with respect to the axis of rotation. For generating such eccentric grooves, the grooves are for example unbalanced clamped in a lathe chuck, but the turning itself is, except for a rotation start and / or a rotation end, as previously known executed. The eccentricity should be, for example, a groove width, preferably three times to six times a groove width.

According to an advantageous embodiment of the friction plate, the at least one elevation curve extends over at least one complete revolution, preferably several revolutions.

Such a survey curve is similar to the meeting of two immediately adjacent groove flanks of conventional grooves or in the form of a spiral (almost) the same. Here, the effect of a certain abrasion for generating abrasion particles, avoiding the formation of circumferential grooves and a reliable removal of abrasion particles is combined. Preferably, these elevation curves are formed by two, several or all groove flanks, and particularly preferably with an eccentricity to the axis of rotation.

According to an advantageous embodiment of the friction plate, the at least one elevation curve on an elliptical shape or waveform, wherein preferably a uniform ellipse is formed with its center on the axis of rotation.

According to this embodiment, the elevation curve, preferably formed by the groove flanks immediately adjacent grooves, differently than described above as a closed curve, ie as a ring formed. In this case, for example, an elliptical shape can be used which has at least a minimum radius at two

Minimal points and at least one maximum radius at two maximum points. As a result, over a course over a complete revolution four times a radius change is achieved, namely an increase and a decrease twice in Change. In a further embodiment, the elevation curve is formed as a ring with a waveform. Thus, a plurality of maximum points and minimum points in the direction of rotation is formed alternately. At the same time, the shaping can be controlled by means of a CNC-controlled lathe.

It is not excluded to arrange the center of these ring shapes eccentrically to the axis of rotation, thereby generating an increase in the radius change as described above. An advantage in an embodiment without such an eccentric arrangement of the center is that in a rotationally symmetrical ring shape, ie a uniform ellipse or a double-symmetrical

Waveform, the resulting radial forces in the interaction of the survey curve with the Gegenreibfläche cancel each other by the negative and the positive changes in radius each other diametrically opposite each other.

According to an advantageous embodiment of the friction plate is formed on the friction surface at least one radially outwardly facing dirt groove, which has an axial depth that in a compressed with a friction partner state of abrasion and at least in the dissolved state a removal of recorded abrasive particles radially outward is possible, wherein the dirt groove is preferably oriented away from radially inward to radially outward from the direction of rotation and / or preferably over the entire radial

Surface width of the friction surface extends.

The dirt groove is deeper than the grooves, so that even at high contact pressures and / or in at least one state, for example, when the friction plate in a separate state abraded against the friction partners, a removal of transported in the dirt groove wear particles is guaranteed. For example, the depth of the dirt groove is 0.1 mm [one tenth of a millimeter] to 1.5 mm, for example, at a width of about 10 mm [ten millimeters] 1.2 mm. The width of a dirt groove, for example, 2 mm to 15 mm, on the one hand, a quick production allows and on the other hand the largest possible effective friction surface (for example, with the grooves) remains. The dirt groove is preferably formed steeper than the elevation curve. As a result, a faster removal of abrasive particles from the dirt groove is facilitated, while the grooves remove the abrasion particles only slowly, so that the wear particles on the one hand not tribologically effective but on the other hand enough

Abrasion particles remain in the grooves, so that the desired damping effect is ensured against a Rupfverhalten the friction pairing.

According to an advantageous embodiment of the friction plate, the friction plate comprises a measuring groove, which is wider and / or deeper than a survey curve, wherein preferably the measuring groove is arranged radially outside of the friction surface.

Because the elevation curve or the grooves with their small groove width and / or small groove depth with simple, for example, contacting,

Measuring means are not reliably detectable, for example, because the measuring head is too large and / or the radial attachment surface (ie, the axial extent of the

Survey curve, for example, a groove flank) is formed too flat, it is advantageous to form a measuring groove, which allows a conclusion about the change in radius. For this purpose, the measuring groove is sufficiently wide or deep to be reliable

Allow measurement with conventional contacting measuring means.

For example, in the case of an elliptical shape, the same shape is depicted with a measuring groove. For example, in a spiral, which is arranged eccentrically, a circular ring, ie with a constant radius, is formed, of which the position of the center, so the eccentricity, for example by means of a three-point measurement, can be detected. The pitch of the spiral itself is sufficiently known as a manufacturing parameter or due to the shape, so that if so desired

(Total) radius change can be calculated.

In order to obtain as much effective friction surface as possible, the measuring groove is preferably introduced radially outside the surface width of the friction surface in the friction plate. For example, the measuring groove is inserted in interrupted segments on radially inwardly or radially outwardly extending flanges, for example for a leaf spring in a friction clutch or for fixing the brake disc to a wheel hub. Alternatively or additionally, if no hundred percent test of the orientation of the radius change is necessary, a marking is provided which indicates the position of the maximum point and / or an eccentricity so that the friction plate can be mounted in the correct angular position.

According to a further aspect, the invention relates to a friction pair arrangement having an axis of rotation for the frictional transmission of a torque as a result of an axial compression of the friction pair arrangement, comprising at least the following components:

at least one friction plate according to an embodiment as described above; and

at least one friction partner with a counter friction surface,

the friction surface of the friction plate being axially compressible with the counter friction surface of the friction partner,

wherein preferably the friction partner is a friction disc and the friction pair arrangement comprises a first friction plate having a first friction surface with a first elevation curve with a first radius change and a second friction surface with a second friction surface with a second elevation curve with a second radius change and the friction disc two corresponding counter friction surfaces the two friction surfaces are formed identically according to an embodiment according to the above description, wherein the direction of rotation of the first radius change of the direction of rotation of the second radius change is arranged in opposite directions.

The friction pair arrangement proposed here is for transmitting a

Torque set up around the axis of rotation. The axis of rotation is congruent with the axis of rotation of the friction plate. The counter friction surface of the friction partner is softer than the friction surface of the friction plate, so that in a frictional engagement abrasive particles are mainly formed by the friction surface.

For example, the counter friction surface is formed by a friction lining, which is preferably exchangeable. The friction surface has at least one elevation curve according to an embodiment as described above, so that formation of circumferential grooves is avoided or at least greatly reduced. Thus, the life of such Gegenreibfläche and the friction surface is clear extended. In addition, the Rupfanfälligkeit is reduced, whereby the comfort increases or the noise emission decreases and also an extension of the life expectancy is to be expected.

In a preferred embodiment, the radii changes are two

Friction surfaces, for example in a friction clutch, with friction plates as

Friction partner, aligned with each other so that a radial force resulting from the change in radius is canceled by the other friction surface. This is particularly effective when the friction disc is disposed between two friction plates, with their resulting from the respective change in radius

Radial forces are diametrically opposed to each other. This is one

Radial force introduced into the friction disc and it is not necessary to form a storage or stiffening against it. The friction plate is designed for such applications already for a desired high heat capacity for receiving and dissipating the heat input in a slipping engagement and hung that the radial forces of a conventional design are already sufficiently counteracted.

According to a further aspect, the invention relates to a dual clutch for a drive train of a motor vehicle, comprising at least the following

components:

a first and a second Reibpaaranordnung according to an embodiment according to the above description with a friction disc as Reibpartner;

an input shaft, which is durable with the friction plates

is connected torque transmitting;

a first output shaft which is permanently connected to transmit torque to the at least one first friction disk of the first Reibpaaranordnung; and a second output shaft connected to the at least one second output shaft

Friction disc of the second Reibpaaranordnung is permanently connected to transmit torque,

wherein the two Reibpaaranordnungen are each compressible separately,

wherein preferably a central web has a first friction surface and a third

Friction surface in one piece each a friction plate of the two Reibpaaranordnungen forms, wherein the direction of rotation of the first radius change of the direction of rotation of the third radius change is arranged in opposite directions.

The dual clutch is designed to release a torque from one

Drive shaft (input shaft) to a consumer and vice versa by means of two output shafts, preferably two transmission input shafts of a double transmission to transfer. This is usually about the one friction package per

Output shaft reached, which has an axially displaceable, usually with the drive shaft rotation-resistant, pressure plate, which is pressed against at least one corresponding friction disc. In most cases, a counter plate is provided, which forms an axial abutment for the contact force, so that the friction disc does not have to be stored against axial forces and / or stiffened. In some

Embodiments are the counter plates of the two friction pack by means of a

Central ridge formed, which is arranged centrally between the friction packs and accordingly has two friction surfaces, which axially

are opposite. In a further embodiment, intermediate plates are provided, which are arranged to be axially displaceable similar to the pressure plate, but are arranged between two friction plates, that is, as a central web has two axially oppositely directed friction surfaces. As a result of the contact force, a frictional force on the friction surface (s), which multiplied by the mean radius of the friction surface, a transmittable torque results in a plurality of such

Friction pairings in total, yields. At least one of the pressure plates, the

Counter plates, the central web and / or the intermediate plate is a friction plate.

For this purpose, the friction disk preferably has two friction linings to the two antagonists of the respective friction pack, which form the respective counter friction surface.

In a preferred embodiment, those are from the radius changes

resulting radial forces on a friction plate with two friction surfaces, ie the central web and / or the intermediate plate, diametrically opposite, so cancel each other on the respective friction plate, the radial forces at the same frictional pressing each other and / or upon intervention of the pressure plates, which preferably according to the above description as well to that

Central web or the intermediate disc has such an orientation of the change in radius that the resulting radial forces on the pressure plate that of the other pressure plate is diametrically opposed. Thus, a possibly excited radial vibration at a simultaneous engagement of the first Reibpakets and disengagement of the second Reibpakets (and vice versa) repealed by the opposite orientation of the change in radius of the friction plates, in particular to the first engaging or last-releasing pressure plate, without the one additional element must be provided for decoupling. If the drag torque in a disengaged state is still so great that noticeable radial forces still occur at least on one of the friction pairings, the same spoiling effect is at least partially achieved.

According to another aspect of the invention is a drive train for a

Motor vehicle proposed which comprises a drive unit with a drive shaft and a dual clutch according to the above description, wherein the drive shaft for torque transmission by means of the double clutch is detachably connectable to at least one consumer.

The powertrain is configured to be one of a power plant, for

Example of an energy conversion machine, preferably one

Internal combustion engine or an electric drive machine,

provided and delivered via its drive shaft torque for at least one consumer detachable, that is switchable and disconnectable to transfer. An exemplary consumer is at least one drive wheel of a motor vehicle and / or an electric generator for providing electrical energy.

Conversely, a recording of an inertial energy introduced, for example, by a drive wheel can also be implemented. The at least one drive wheel then forms the drive unit, wherein its inertial energy by means of

Double clutch on an electric generator for recuperation, so for the electrical storage of braking energy, with a suitably equipped drive train is transferable. Furthermore, in a preferred embodiment, a plurality of drive units are provided, which by means of

Double clutch in series or connected in parallel or decoupled from each other are operable, or their torque is releasably available for use available. Examples are hybrid electric drives Drive engine and internal combustion engine, but also multi-cylinder engines in which individual cylinders (groups) are switchable.

To the torque targeted and / or by means of a gearbox with

To transmit different translations or to separate a transmission, the use of the above-described double clutch is particularly advantageous. The double clutch proposed here allows an extended life of the friction pair, preferably at least the friction linings, at the same time a low Rupfanfälligkeit at least one of the friction packs.

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.

Most motor vehicles today have a front-wheel drive and therefore preferably arrange the drive unit, for example one

Internal combustion engine or an electric drive machine, in front of the cab and across or along the main direction of travel.

The drive train described above has a double clutch, which allows an extension of the life of the friction surface and / or the counter friction surface of a friction pair, while at the same time the Rupfanfälligkeit is low. This allows maintenance intervals to be extended.

Passenger cars are assigned to a vehicle class according to, for example, size, price, weight and power, and this definition is subject to constant change according to the needs of the market. In the US market, cars of the class small cars and microcars are classified according to European classification of the class of Subcompact Car and in the British market they correspond to the class Supermini or the class City Car. Examples of the micro car class are a Volkswagen up! or a Renault Twingo. Examples of the small car class are an Alfa Romeo Mito, Volkswagen Polo, Ford Fiesta or Renault Clio. The above-described invention will be explained in detail in the background of the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is not limited by the purely schematic drawings in any way, it being noted that the drawings are not dimensionally accurate and are not suitable for the definition of size ratios. It is shown in

Fig. 1: Top view of a friction plate with eccentric spiral and dirt groove;

2 shows a sectional view of a friction pair arrangement with abrasive particles;

3 shows a sectional view of a friction pair arrangement with buried circumferential grooves;

4 shows a survey curve as a mathematical spiral;

5 shows a survey curve as a CNC spiral;

Fig. 6: Top view of a friction plate with ellipse;

Fig. 7: sectional view of a double clutch with opposite

Radii change;

8 shows a plan view of a friction plate with eccentric spiral and measuring groove;

9 shows a sectional view of a measuring groove in a first embodiment;

10 shows a sectional view of a measuring groove in a second embodiment; and

Fig. 11: a drive train in a motor vehicle with dual clutch.

Ordinal numbers used in the preceding and following descriptions, unless explicitly stated to the contrary, are for the purpose of distinctness only and do not disclose the order or ranking of the designated components. In Fig. 1, a first friction plate 1 with a frictional surface width 8 in

Top view along the rotation axis 3 shown. The first friction plate 1 is mounted here in an axially movable by means of leaf springs 58 on flanges 59 on a co-rotating lid 57 and is for example a pressure plate. The axis of rotation 3 is the torque transmission axis to which the components are aligned and balanced. The first friction plate 1 has a first one

Friction surface 4, in which a survey curve 15, here formed as a spiral over several complete revolutions 30, is introduced in exaggerated representation. The spiral of the elevation curve 15 has a minimum point 24 with a

Minimum radius 26, wherein the elevation curve 15 in its course 16 a

Gradient radius 18 which is formed in a first direction of rotation 12 continuously, and preferably continuously. The center of the elevation curve 15 is arranged with an eccentricity 60 to the axis of rotation 3, so that there is a spiral shape overlying first change in radius 19, the maximum point 21 with its maximum radius 23 because of the spiral shape (also exaggerated here) as shown slightly counterclockwise twisted next to the direction of eccentricity 60 is formed. Likewise, the minimum point 24 is with his

Minimal radius 26 (here also shown exaggerated) as shown twisted slightly counterclockwise next to the opposite direction of the eccentricity 60 formed. Here, simplified is the eccentricity 60 referred to as a change in radius 19, wherein the change in radius 19 is composed of the increase in radius due to the spiral shape of the elevation curve 15 and the eccentricity 60. Furthermore, here are optional and independent of the shape of the elevation curve 19 and type of

Friction plate 1 three grooves 33 created which are inclined away from a direction of rotation 36 at about 45 ° to a radial direction outwardly inclined. These allow a targeted removal of abrasion particles 35, so that they do not accumulate in the grooves (see FIGS. 2 and 3) and thus can not become tribologically effective.

In Fig. 2 is a fragmentary friction pair 38, comprising a

Friction plate 1 in frictional contact with a friction disc 40, shown in section, which can be pressed together by means of an axial force in the axial direction 17. Here is a friction surface 4 is formed, which forms on average a plane perpendicular to the axial direction 17 9 for the frictional contact with the counter friction surface 42 of the friction disc 40. This friction surface 4 has a plurality of immediately adjacent grooves 10, in each of which abrasion particles 35 are received. For this purpose, each groove 10, which are all optionally identical here, has a groove valley 11 with a groove width 14, which in the illustration above is a first one

Rillenberg flank 28 and bottom of a second groove mountain flank 29 is limited.

Two immediately adjacent groove flanks form an acute transition 27, which according to one embodiment, the elevation curve 15 with a

corresponding axial extent towards the friction disc 40 forms. Furthermore, dashed lines here, because hidden in this view, a groove bottom of a dirt groove 33 is shown, which has a much greater axial depth 34 than the grooves 10. This representation too is an exaggeration to clarify the forms, from which no size ratios can be taken. In this

Representation of the groove contour is not different from a conventional groove contour.

In Fig. 3, a conventional groove contour is shown in a same view. In that regard, reference is made to the preceding description. Here is the

Radial change 19 (see, for example, Fig. 1) chosen too low, so that at the acute transitions 27 recirculating grooves 73 have formed, which in

Contact buckling 74 results. The contact curvatures 74 protrude into the grooves 10, so that now the abrasion particles 35 become tribologically effective.

FIGS. 4 and 5 show in comparison two elevation curves 15, each with a continuous continuous course 16 in the direction of circulation 12 and over a complete revolution 30 (exaggerated), once as an ideal (mathematical) spiral 61 (FIGS. 4) and once formed as a CNC spiral 62 (Figure 5). Is the

Gradient radius 18 is placed on a center of both axes of rotation 2 (see, for example, Fig. 1), so the minimum point 24 with a minimum radius 26 on

Beginning of the curve and a maximum point 21 with a maximum radius 23 at

Curve end formed. Already in a mathematical spiral 61 is the

Radial change 19 at, for example, a groove width 14 of 0.3 mm so small that large equi-components of the radius of curvature 18 are present and thus circumferential grooves 73rd (See Fig. 3) can generate. But if a CNC spiral 62 is formed, the DC components are still significantly larger, resulting from the smaller amount of

Radii change 19 is clearly visible.

In Fig. 6 is a first friction plate 1 with a frictional surface width 8 in

Top view along the axis of rotation 3 similar to that shown in Fig. 1. In that regard, reference is made to the description of FIG. 1. However, the elevation curve 15 is formed here as an ellipse 31 (shown exaggeratedly), the center 32 of which is optionally arranged here on the axis of rotation 3. This results along the course 16 in the circumferential direction 12 over a complete circulation 30, a rotationally symmetric change in radius 19 with a first minimum point 24 and a second

Minimum point 25 with a minimum radius 26 and with a first maximum point 21 and a second maximum point 22 with a maximum radius 23. Resulting radial forces thus cancel each other out.

In Fig. 7, a double clutch 46 is shown with a co-rotating lid 57 in section, wherein a torque about the rotation axis 3 by means of a first Reibpaaranordnung 38, or a first Reibpakets, of a

Input shaft 49 to a first output shaft 50 and by means of a second

Reibpaaranordnung 39, or a second Reibpakets, of the

Input shaft 49 on a second output shaft 63 releasably, namely frictionally engaged, transferable. Within the lid 57, a vibration damper 64 is shown here, for example, a dual mass flywheel. The first

Reibpaaranordnung 38 includes a first friction plate 1, here a pressure plate, a central web 51 (axially rigid counter-plate) and axially disposed therebetween first friction disc 40, which are axially compressible by means of a first actuator unit 65. The second Reibpaaranordnung 39 includes a second friction plate 2, here a pressure plate, the central web 51 and an axially disposed therebetween second friction disc 41, which are axially compressible by means of a second actuator unit 66. The central web 51 has in the illustration on the left, ie belonging to the first Reibpaaranordnung 38, a first friction surface 4, which is frictionally engageable with the first Gegenreibfläche 42 of the first friction disc 40 in contact. The first friction plate 1 has a second friction surface 5, which is frictionally engageable with the second counter-friction surface 43 of the first friction disc 40 in contact. Furthermore, the central web 51 in the representation on the right, ie belonging to the second friction pair 39, a third friction surface 6, which is frictionally engageable with the third Gegenreibfläche 44 of the second friction plate 41 in contact. The second friction plate 2 has a fourth friction surface 7, which is frictionally engageable with the fourth Gegenreibfläche 45 of the second friction plate 41 in contact. Here, the first friction plate 1 with its second friction surface 5 a

Survey curve 15 with a first change in radius 19, for example, an offset to the rotation axis 3 in the representation upwards eccentricity 60 (see, for example, Fig. 1), and the central web 51 with its first friction surface 4 a survey curve 15 with a second change in radius 20, for example a to the rotation axis 3 in the representation downwardly offset eccentricity 60 (see, for example, Fig. 1) same amount as the first change in radius 19, on. The first direction of rotation 12 of the elevation curve 15 of the first friction plate 1 and the second direction of rotation 13 of the elevation curve 15 of the central web 51 are opposite to each other. As a result, and as a result of a corresponding (rigid) relative angular position, the two radial changes 19 and 20 are aligned so that the resulting radial forces of the first Reibpaaranordnung 38 pay off each other. In this illustration, at the third friction surface 6, a first circumferential direction 12, that is, inversely to the first friction surface 4 of the central web 51, and at the fourth friction surface 7, a second circumferential direction 13 is formed. Alternatively, no elevation curve is formed here.

In Fig. 8, a friction plate 1 is shown in a same view as in Fig. 1 and in Fig. 6, so that reference is made to the description there. The

Friction plate 1 has an elevation curve 15 formed as a CNC spiral 62, which is arranged with an eccentricity 60 to the rotation axis 3, so that here simplified as identical to the eccentricity 60 shown, a change in radius 19 along the course 16 in the direction of rotation 12 results , Because the grooves 10 (see FIG. 2) are relatively small, for a simpler measurement of the angular position of the eccentricity 60 a measuring groove 37 is provided in the flanges 59, ie radially outside the friction-effective surface width 8, with a preferably constant measuring groove radius 67, ie one circular measuring groove 37, formed. FIGS. 9 and 10 show, in section, two embodiments of a measuring groove 37, which has a measuring groove width 69 such that a measuring head 68 can be easily placed therein (coarse) and a sufficient measuring groove depth 70 that the measuring head bears radially can be brought. The wall of the measuring groove 37 is in the embodiment of FIG. 9 parallel to the rotation axis 3 (see FIG. 8) and in the embodiment of FIG. 10 inclined to the rotation axis 3 (see FIG. 8) formed such that an open Measuring groove 37 for

For example, a simplified insertion of the measuring head 68 results. In Fig. 11, a drive train 47, comprising a drive unit 71, shown here as a three-cylinder internal combustion engine, a drive shaft 72, a dual clutch 46 and a releasably torque transmitting connected left drive wheel 52 and right drive wheel 53, shown schematically. The

Drive shaft 72 forms directly the input shaft 49 of the double clutch 46, for example, as shown in Fig. 7. The drive train 47 is here in one

Motor vehicle 48 is arranged, wherein the drive unit 71 with his

Motor axis 56 is arranged transversely to the longitudinal axis 55 in front of the driver's cab 54.

With the friction plate proposed here with a pointed elevation curve, a good damping property is achieved and at the same time a formation of circumferential grooves is avoided.

LIST OF REFERENCES

first friction plate

second friction plate

axis of rotation

first friction surface

second friction surface

third friction surface

fourth friction surface

surface width

vertical plane

groove

Rillental

first direction of rotation

second direction of rotation

groove width

lift curve

course

axial direction

History radius

first radius change

second radius change

first maximum point

second maximum point

maximum radius

first minimum point

second minimum point

R.min.

sharp transition

first groove mountain flank

second Rillenberg flank

complete circulation ellipse

Focus

dirt groove

axial depth

wear particles

direction of rotation

measurement groove

first friction pair arrangement second friction pair arrangement first friction disk second friction disk first counter friction surface second counter friction surface third counter friction surface fourth counter friction surface double clutch

powertrain

motor vehicle

input shaft

first output shaft central web

left drive wheel right drive wheel cab

longitudinal axis

motor axis

cover

leaf spring

flange

eccentricity

ideal spiral

CNC spiral

second output shaft vibration damper first actuation unit second actuation unit measuring groove radius

probe

Messnutbreite

Messnuttiefe

power unit

drive shaft

circumferential groove

Contact vaults

Claims

claims

1. friction plate (1, 2) for axial compression with a friction partner (40,41) for

Frictionally transmitting a torque about an axis of rotation (3), wherein the friction plate (1, 2) at least one friction surface (4, 5, 6, 7) with a radial surface width (8) in a plane (9) perpendicular to the axis of rotation (3 ), and

wherein the friction surface (4, 5, 6, 7) has a plurality of grooves (10) with a

Groove groove (11) and two grooved mountain flanks (28,29) each adjacent to a further groove (10) of the plurality of grooves (10), wherein the grooves (10) in the circumferential direction (12,13) extend and each have a groove width ( 14), and

wherein the friction surface (4, 5, 6, 7) has at least one elevation curve (15) with a continuous profile (16) over at least 90 ° in the direction of rotation (12, 13), wherein the elevation curve (15) extends axially out of the

Fringing surface (4, 5, 6, 7) extends out and in the axial direction (17) is pointed, wherein the elevation curve (15) has a radius of curvature (18) to the rotation axis (3), wherein the elevation curve (15) in its Course (16) in the direction of rotation (12,13) has a change in radius (19,20), wherein the

Elevation curve (15) has a maximum point (21, 22) with a maximum radius (23) and a minimum point (24, 25) with a minimum radius (26),

characterized in that

the radius of curvature (18) has a change in radius (19, 20) such that the maximum radius (23) is greater than the minimum radius (26) by at least 1.5 times the groove width (14).

2. friction plate (1, 2) according to claim 1, wherein the elevation curve (15) of the, preferably unsteady, transition (27) from a groove mountain flank (28,29) to the adjacent groove mountain flank (28,29) is formed, preferably a plurality of radially parallel grooves (10) with radially outwardly increasing

Gradient radius (18), preferably concentric with the axis of rotation (3) and / or preferably with the same groove width (14) is formed.

3. friction plate (1, 2) according to claim 2, wherein the radius of curvature (18) of the at least one elevation curve (15) in the circumferential direction (12,13), preferably constant, increases.

4. friction plate (1, 2) according to claim 2 or 3, wherein the at least one

Collection curve (15) over at least one complete circulation (30), preferably several revolutions (30), runs.

5. friction plate (1, 2) according to any one of the preceding claims, wherein the at least one elevation curve (15) has an elliptical shape (31) or waveform, wherein preferably a uniform ellipse (31) with its center (32) on the axis of rotation ( 3) is formed.

6. friction plate (1, 2) according to one of the preceding claims, wherein on the

Friction surface (4, 5, 6, 7) at least one pointing radially outward

Dirt groove (33) is formed, which has an axial depth (34) that in a compressed with a friction partner (40,41) state receiving a

Abriebpartikeln (35) and at least in the dissolved state, a removal of recorded abrasion particles (35) is allowed radially outward, wherein the dirt groove (33) preferably from radially inward to radially outward of the

Direction of rotation (36) is oriented inclined and / or preferably extends over the entire radial surface width (8) of the friction surface (4, 5, 6, 7).

7. friction plate (1, 2) according to one of the preceding claims, wherein the

Friction plate (1, 2) comprises a measuring groove (37) which is wider and / or deeper than a survey curve (15), wherein preferably the measuring groove (37) radially outside the friction surface (4, 5, 6, 7) is arranged.

8. Reibpaaranordnung (38,39) having an axis of rotation (3) for the frictional transmission of torque due to an axial compression of the

Friction pair arrangement (38, 39) comprising at least the following components:

- At least one friction plate (1, 2) according to one of the preceding claims; and

at least one friction partner (40, 41) with a counter friction surface (42, 43, 44, 45), wherein the friction surface (4, 5, 6, 7) of the friction plate (1, 2) with the

Gegenreibfläche (42,43,44,45) of the friction partner (40,41) is axially compressible, wherein preferably the friction partner is a friction disc (40,41) and the

Reibpaaranordnung (38,39) a first friction plate (1, 2) with a first

Friction surface (4, 5, 6, 7) having a first elevation curve (15) with a first radius change (19, 20) and a second friction surface (4, 5, 6, 7) with a second friction surface (4, 5, 6, 7) with a second elevation curve (15) with a second change in radius (19,20) and the friction disc (40,41) two

corresponding counter friction surfaces (42,43,44,45), wherein the two friction surfaces (4, 5, 6, 7) are formed similar to one of the preceding claims, wherein the circumferential direction (12,13) of the first

Radial change (19,20) of the direction of rotation (12,13) of the second

Radial change (19,20) is arranged in opposite directions.

9. dual clutch (46) for a drive train (47) of a motor vehicle (48), comprising at least the following components:

- A first and a second Reibpaaranordnung (38,39) according to claim 8 with a friction disc (40,41) as a friction partner;

- An input shaft (49), which with the friction plates (1, 2) permanently

is connected torque transmitting;

- A first output shaft (50,63), which with the at least one first friction disc (40,41) of the first Reibpaaranordnung (38,39) permanently

is connected torque transmitting; and

- A second output shaft (50,63) which with the at least one second friction disc (40,41) of the second Reibpaaranordnung (38,39) permanently

connected torque transmitting,

wherein the two Reibpaaranordnungen (38,39) are each separately compressible, wherein preferably a central web (51) a first friction surface (4, 5, 6, 7) and a third friction surface (4, 5, 6, 7) in one piece each a friction plate (1, 2) of the two Reibpaaranordnungen (38,39) forms, wherein the direction of rotation (12,13) of the first change in radius (19,20) of the direction of rotation (12,13) of the third

Radial change (19,20) is arranged in opposite directions.