Friction device with rotating shaft for torsional vibration damper

Abstract

The present invention relates to a friction device (1) having a rotating shaft (2) for a torsional vibration damper (3), comprising at least the following components: an input side (4) having a first input disc (5) and a second input disc (6); an output side (7) having an energy storage element (8), a first friction disc (9) and a second friction disc (10), wherein the axial force (17, 18, 19) of the energy storage element (8) is from the energy storage element (8) to the friction discs (9, 10) via at least one of the contact areas (11, 12, 13); and - guided from the friction discs (9, 10) on the respective input discs (5, 6) via at least one of the friction zones (14, 15, 16), The present invention relates to a friction device (1), in which a first one of the contact areas (11) and a first one of the friction zones (14) are arranged on a first respective diameter (27, 28) and a second one of the contact areas (12) and a second one of the friction zones (15) are arranged on a respective second diameter (29, 30) different from the respective first diameter (27, 28). The friction device (1) is mainly characterized in that a first axial distance (33) between the first contact area (11) and the first friction zone (14) is different from a second axial distance (34) between the second contact area (12) and the second friction zone (15). With the friction device proposed herein, the usable range of motion is increased without requiring additional installation space or additional components.

Description

[Technical field]

[0001] The present invention relates to a friction device having a rotating shaft for a torsional vibration damper, comprising at least the following components: an input side having a first input disc and having a second input disc; an output side having an energy storage element, a first friction disc and a second friction disc, wherein the axial force of the energy storage element is in each case at least one of the contact areas from the energy storage element to the friction disc, and in each case from the friction disc to the corresponding input disc via at least one of the friction zones, The invention relates to a friction device, in which a first one of the contact areas and a first one of the friction zones each have a first diameter and a second one of the contact areas and a second one of the friction zones each are arranged on a second diameter different from the respective first diameter. The friction device is mainly characterized in that a first axial distance between the first contact area and the first friction zone is different from a second axial distance between the second contact area and the second friction zone. The invention further relates to a torsional vibration damper for a drivetrain, to a drivetrain comprising such a torsional vibration damper and to a motor vehicle comprising such a drivetrain. [Background technology]

[0002] Friction devices are used in torsional vibration dampers to apply relative rotation about an axis of rotation between an input side and an output side in a targeted manner to appropriately extract energy from a vibrating system, thereby damping the vibrating system.

[0003] Torsional vibration dampers are used in particular to reduce torsional vibrations in drive trains. In particular, torsional elasticity is introduced into the drive train, which is excited by periodic disturbances. The aim here is to shift destructive vibration resonances occurring in various operating situations as far as possible to a speed range below the operating speed. Vibration resonances that remain within the operating speed range are damped by external or integrated friction devices, the friction torque of which must be within defined limits. The friction devices can be designed so that they do not rely on torsional elasticity.

[0004] It is known to use an axially acting energy storage element (e.g. corrugated disk or disk spring) together with an associated friction disk (and optionally a support disk) as a friction device arranged axially between components coupled to the input and output sides. The axial force of the energy store in the installed position, the friction radius of the friction element and the friction coefficient of the material pair define a friction torque that is substantially constant over the relative rotation about the axis of rotation. For different operating points (or driving conditions used in the vehicle) requiring different levels of friction torque, friction devices designed for different friction torques are provided, which experience their relative rotation about the axis of rotation in the associated rotation angle range of the torsional vibration damper.

[0005] If the radial installation space available for the friction device is limited, only a limited level of difference can be set for the resulting friction torque by simply varying the friction radius between identical friction counterparts. Due to the requirement for small diameters of components for the drivetrain and the pressure on costs, the very short usable travel range of the energy storage element in terms of manufacturing and assembly tolerances, as well as the necessary constancy over the desired service life, are important. Nevertheless, lengthening the axial length of the friction device or even the torsional vibration damper is often not an option. Summary of the Invention [Problem to be solved by the invention]

[0006] Proceeding therefrom, the object of the present invention is to at least partially overcome the drawbacks known from the prior art. Features according to the invention arise from the independent claims, advantageous embodiments of which are set out in the dependent claims. The features of the claims can be combined in any technically reasonable manner, and features from the explanations and drawings in the following description, including additional embodiments of the invention, can also be used for this purpose. [Means for solving the problem]

[0007] The present invention relates to a friction device having a rotating shaft for a torsional vibration damper, comprising at least the following components: an input side having a first input disc and having a second input disc, the first input disc and the second input disc being coupled to each other; an output side having an energy storage element, a first friction disc and a second friction disc, the energy storage element being arranged axially between the friction discs, the friction discs having a plurality of contact areas on the side of the energy storage element and a plurality of friction zones on the side of the input disc, Torque can be transmitted by friction between the input and output sides, with the energy storage element being pretensioned to apply an axial force, which is in each case at least one of the contact areas of the energy storage element on the respective friction disc, and in each case via at least one of the friction zones of the friction disc on the corresponding input disc, A relative twist angle about the axis of rotation may result between the output side and the input side as a result of the torque gradient, the twist angle being: - the amount of axial force, and - depending on the contact area and / or friction zone, through which the axial force is transmitted, The present invention relates to a friction device, wherein a first one of the contact areas and a first one of the friction zones each have a first diameter, and a second one of the contact areas and a second one of the friction zones each are disposed on a second diameter, and at least one of the first diameters is different from the second diameter of a respective equilateral side.

[0008] The friction device is primarily characterized in that a first axial distance between the first contact area and the first friction zone is different from a second axial distance between the second contact area and the second friction zone.

[0009] In the following, unless otherwise specified, when axial, radial or circumferential and corresponding terms are used, reference is made to the specified axis of rotation. Unless otherwise specified, ordinal numbers used in the preceding and following descriptions are used for distinguishing purposes only and do not indicate the order or ranking of the named components. An ordinal number greater than 1 does not necessarily imply that such other components must be present.

[0010] As explained above, the friction device proposed here is set to provide a desired torsional elasticity in the drive train, and a defined friction torque is generated between the input side and the output side by the pretensioned energy storage element and the friction disk. What is special here is that the energy storage element is pretensioned to different degrees depending on the relative torsion angle between the input side and the output side, so that for example a larger relative torsion angle can result in a larger change in the friction torque transmitted between the input side and the output side. The basic principle of this friction device corresponds to a first approximation of a slipping clutch, whereby no torque limit value is set here and (additional) excessive torque cannot be transmitted, but different torsion angle-dependent (defined) torques can be transmitted to the maximum extent. The torsion angle depends on the torque source between the input side and the output side, and the friction device is preferably set for torques in both directions around the rotation axis (for example traction torque and thrust torque in the drive train of a vehicle). It should be noted that torque can be (applied and transmitted) via the input side (with respect to the respective inertial components) and via the output side. For example, when used in a motor vehicle, the input side can be used both as an input side for traction torque and as an input side for thrust torque. As a result, the opposite applies to the output side. The energy storage element is arranged between the first and second friction discs and is pretensioned directly or indirectly by the friction discs. For this purpose, each of the friction discs has at least one contact area, via which the friction discs are in direct or indirect force-transmitting contact with the energy storage element. In a preferred embodiment, there is no or only very little relative rotation between the contact area and the energy storage element. Thus, friction wear on the energy storage element and also on the contact area of ​​the friction disc is eliminated or is kept sufficiently low at least for the desired service life. On the other hand, i.e. axially outward, or on the side of the input disc seen from the energy storage element, the friction discs each have at least one friction zone in direct or indirect contact with the corresponding input disc.In preferred embodiments, there is in each case only relative rotation (direct or indirect) and transmission of friction torque between the friction zone of the friction disc and the corresponding input disc. In preferred embodiments, the friction torque between at least the friction zone and the input disc is the relevant friction torque, other friction torques and / or elastic forces are either negligible or (almost) constant over the relative twist angle.

[0011] In the unloaded state of the friction device, as a result of the existing axial pretension of the energy storage element, a predetermined first maximum torque can be transferred from the input side to the output side and vice versa. However, if there is a torque gradient between the input side and the output side that is greater than the stated maximum torque, a relative twist occurs between the input side and the output side, which results in a corresponding twist angle about the axis of rotation. As a result of the ramp shape of at least one of the at least one friction zone and / or at least one of the input disks, the relative twist angle is converted into an axial stroke, which acts as an axial stroke of the energy storage element, and as a result, the amount of axial force changes.

[0012] The first contact area of ​​one of the friction disks is arranged on a first diameter, operates with a first helix angle, and is arranged on an associated or derived first friction zone, which is arranged on the first diameter for the transmission of axial forces. Furthermore, the second contact area and the associated or derived second friction zone are arranged on a second diameter, respectively. It should be noted that the first diameters in an embodiment are identical or different from each other, and the contact areas preferably include in each case a small contact area that approximates a line contact, which defines the first diameter on the side of the energy storage element. The radial extent of the friction zones is preferably not designed for a pure line contact, but for a contact over the maximum possible area, so that the corresponding diameter is preferably a mean diameter, which is used as an approximate criterion for calculating the maximum transmittable friction torque. Herein, for a second twist angle greater than the first twist angle, for example when the first twist angle is in the zero position, a second contact area different from the first contact area and / or a second friction zone associated with the second twist angle different from the first friction zone is provided. The first and second contact areas and / or the first and second friction zones are each different from each other in terms of their diameters. It should be pointed out that here too, the different diameters of the two contact areas lead to different contacts on the energy storage element (as a result of the tilt), and the different diameters of the friction zones lead to different friction radii or diameters, and therefore the same axial force is assumed for different maximum transmittable friction torques (approximately proportional to the diameter).

[0013] Here, it is proposed here that in the case of at least one of the friction discs, when the axial force is transmitted, two different distances are formed depending on the helix angle present. As a result of the different distances, depending on the helix angle present, different pretension forces are also generated on the energy storage element, which results in a larger effective axial force and / or a larger deformation of the friction disc, for example achieving an increase in the effective area of ​​the friction zone. For example, this means that the friction zones arranged on different diameters overlap each other. It is noted that in one embodiment, the first and second friction zones are identical to each other. In another embodiment, the first and second contact areas are identical to each other. Identical contact areas or friction zones have the same (effective) diameter. In a preferred embodiment, the respective friction zones are radially inclined with respect to the corresponding counter-friction surface of the respective input disc, and the axial distances defined here are defined between the highest elevation of the friction zone and the contact area of ​​the respective friction disc. It should also be noted that this axial distance is defined by the relaxed position or shape of the friction discs and does not exist or depend on the twist angle due to the introduction of forces with the respective input discs and energy storage elements through deformation of the friction discs.

[0014] In an advantageous embodiment of the friction device, it is also proposed that the first and second friction zones merge into one another in the circumferential and radial directions in the form of a ramp.

[0015] In this embodiment, the resulting inclination of the energy storage element, in addition to the ramp ratio (in the direction of rotation), is used to transition the force transfer from the energy storage element (e.g. disk spring) to another contact area to the friction disk and / or to vary the force introduction to the friction disk so that another friction zone of a different diameter with a lower torque gradient additionally or alternatively comes into contact (directly or indirectly) for frictional coupling with the input disk. In one embodiment, a gradual ramp-like transition is formed between the different contact areas and / or different friction zones, which is oriented in the radial direction in contrast to the ramp-like translation for the axial pretension of the energy storage element aligned in the direction of rotation. These two ramps are therefore superimposed on each other. Such a smooth transition has advantages in terms of partial stresses and (thus avoided or at least reduced) noise induction.

[0016] In an advantageous embodiment of the friction device, it is also proposed that the first and second contact areas protrude from the surface of the associated friction disc facing the energy storage element at different heights, and that at least one of the contact areas is preferably formed to be dome-shaped.

[0017] It is proposed here that the two contact areas project in two different diameters with different heights from each other. This means that the axial distance between the energy storage element and the friction disc is different and / or the axial thickness of the friction disc is different in the areas of different diameters of the contact area. In case of different axial thicknesses of the friction disc, this means that the contact area with a higher height is formed in a part of the friction plate where the friction plate is thinner than in the area where the other contact areas with a lower height are formed. In a preferred embodiment, the friction disc is thinner in the higher contact area, which is arranged axially closer to the energy storage element. In a preferred embodiment, the radially inner contact area is designed with a higher height.

[0018] In an advantageous embodiment, at least one of the contact areas is formed with a pointed shape, so that a contact line is at least approximately formed despite tilting of the energy storage element over the usable range of movement. In one embodiment, the contact areas are formed as circumferential closed rings or individual protrusions, each contact area being preferably arranged on a defined diameter with respect to the axis of rotation.

[0019] It is further proposed that in an advantageous embodiment of the friction device, the input disc has a predetermined overall axial resilience such that the overall resilience increases the usable range of movement by a factor of 1.5 to 3.

[0020] It is proposed here that the input disc has a given total axial elasticity, which is set such that the usable range of movement is increased by a factor of 1.5 [1.5] to 3 [3]. The usable range of movement of the energy storage element, preferably a disc spring, is therefore enlarged as a result of this series coupling. The total elasticity is the spring characteristic curve for the input disc. It is noted that the input discs are interconnected and that although in some circumstances the couplings may contribute to the total elasticity, preferably the partial elasticity of the couplings is small or negligible compared to the elasticity of the input disc itself, i.e. the design is stiff in comparison.

[0021] Each input disk is preferably integrally formed so that the number of joints contributing to the total elasticity is as small as possible. In the movement force diagram, the total elasticity (i.e. the spring characteristic curve) is such that in a maximally stiff embodiment of the total elasticity (i.e. a very stiff input disk), the total elasticity extends the usable range of movement of the energy storage element by 50% [50 percent] (i.e. additionally), so that the minimum usable range of movement is therefore 1.5 times the usable range of movement of the energy storage element. In the case of a maximally soft total elasticity (i.e. at least a very soft input disk), the usable range of movement of the energy storage element is (additionally) doubled, so that the maximum usable range of movement is three times the usable range of movement of the energy storage element. In a preferred embodiment, the total elasticity is a straight line, or (almost) a straight line within the required effective range. In the superposition of the total elasticity of the input disk with the spring characteristic curve of the energy storage element, there is a fairly long usable range of movement between the minimum and maximum usable forces, which is required by the friction device to achieve the corresponding frictionally transmittable torque according to the design.

[0022] It should be pointed out that the axial force arises from the force of the energy storage element and is approximately the same in magnitude and direction.

[0023] It should be pointed out that the definition of the total elasticity relative to the average friction diameter of the diameter or total area of ​​friction zones present in the friction device is relative to the axis of rotation.

[0024] It is also proposed in advantageous embodiments of the friction device that the ratio of the maximum available force to the minimum available force is greater than 1.5 or greater than 2.

[0025] It is proposed here to operate the energy storage element so that its maximum available force divided by the minimum available force is greater than 1.5 [1.5] or greater than 2 [2]. Which embodiment is advantageous depends on the installation situation or specifications. It is noted that in both cases the ratio of the overall characteristic curve resulting from the series combination of the overall resilience and the spring characteristic curve for the energy storage element to the spring characteristic curve is 1.5 to 3 as specified above, and therefore is not designed to be dependent on this.

[0026] In one embodiment of the overall characteristic curve having a ratio of maximum available force [numerator] to minimum available force [denominator] greater than 1.5 [1.5] and less than or equal to 2 [2], preferably only the range of travel starting from the local minimum (to the right of the plateau of the energy storage element) is used.

[0027] In embodiments of the overall characteristic curve having a ratio of maximum available force [numerator] to minimum available force [denominator] greater than 2 [2], the range of travel is preferably used to both the left and right of the plateau. In a preferred embodiment, the plateau is located approximately or exactly halfway between the minimum and maximum available forces.

[0028] In an advantageous embodiment of the friction device, at least one of the input discs has sector breakouts and radial webs between the sector breakouts, The anti-friction surface for the friction zone of the corresponding friction disc is formed by the radial web, the radial webs have a web resilience about which a major portion of the predetermined overall resilience is formed; It is also proposed that the web elasticity is preferably variable depending on the effective abutment diameter of the corresponding friction zone.

[0029] It is now proposed here that at least one of the input discs has sector breakouts and has radial webs remaining between the sector breakouts with a defined web elasticity, so that the overall elasticity is achieved to a large extent. This web elasticity depends on the length of the web and on the width and thickness of the radial web. Furthermore, the web elasticity depends on the ribs or flanged edges. Thus, there is a considerable degree of freedom in setting the web elasticity. In one embodiment, each other input disc is formed continuously without sector breakouts, which means that there is a higher axial stiffness compared to input discs with sector breakouts and / or a higher torque stiffness between the inner and outer circumference compared to input discs with sector breakouts.

[0030] In an advantageous embodiment, the web elasticity is set so that it can be varied over the effectively applied diameter of the corresponding friction zone of the friction disc. For example, the change in web elasticity corresponding to the change in the elasticity of the friction disc is adjusted as a function of the diameter offset, as described above, so that the overall elasticity of the input disc together with the elasticity of the associated friction disc produces a (nearly) linear spring characteristic curve. This is advantageous with respect to the controllability of the overall structure, but not necessarily advantageous for the operation of such a friction device.

[0031] In an advantageous embodiment of the friction device, the friction discs are each arranged such that a torque is transmitted via the suspension of the friction disc which is effective in the direction of rotation. - has a separate coupling element arranged for a torque-transmitting coupling to the output side; and / or -It has also been proposed that they are bonded to each other.

[0032] As already mentioned above, the relative movements between the friction discs and the energy storage element are preferably prevented or kept small. It is proposed here that the friction discs are fixed to each other and therefore to the energy storage element via corresponding suspensions with separate connecting elements, for example shaft or hub elements, and / or that the friction discs are connected to each other via suspensions. Such suspensions are, for example, tabs pointing radially inward or outward, the suspensions for connecting the friction discs to each other preferably forming axial enlargements on the radially outer or radially inner sides of the energy storage element.

[0033] In an advantageous embodiment of the friction device, it is also proposed that the energy storage element is coupled in such a way that a torque is transmitted to one of the friction discs via a suspension of the energy storage element which is effective in the direction of rotation.

[0034] In order to achieve the above-mentioned goal of little or no relative movement between the energy storage element and the friction discs, it is proposed here that a suspension is provided on the energy storage element, which is coupled to at least one of the friction discs, so that relative movements in the direction of rotation are prevented. These attachments are also designed, for example, as tabs oriented radially outward or radially inward, with or without an axial widening. It is irrelevant whether tabs are provided on the friction disc or on the energy storage element, or whether corresponding recesses are provided on the friction disc or on the energy storage element.

[0035] According to a further aspect, there is provided a torsional vibration damper for a drivetrain, comprising: comprising an input element and an output element according to the embodiment described above and a friction device, an input element coupled to an output element by a friction device for dissipatively damped torque transmission; A torsional vibration damper has been proposed, preferably used as a pendulum rocker damper.

[0036] Torsional vibration dampers are known from the prior art and are widely used, for example, in hybrid applications involving internal combustion engines and engines (for example in the automotive field), whose rotational roughness is reduced during operation by a torque limiter that filters excessive torque from the torsional vibration damper and the drivetrain, protecting the drivetrain from damage in the event of critical resonant drive conditions. For some applications, it is desirable to provide a hysteresis characteristic by at least one friction device, whereby the response behavior of the torsional vibration damper is delayed or adjusted. Alternatively, a friction device is coupled upstream or downstream of the torsional vibration damper, with the torsional vibration damper preferably working (almost) dissipatively and the friction device for dissipative damping working in a defined torque range (via the torsion angle).

[0037] So-called pendulum rocker dampers are known from the prior art as a special embodiment of torsional vibration dampers. For example, the concept of adjusting the stiffness of a rotating shaft or a rotating shaft system in a drive train is known from DE 10 2019 / 121204 (A1) and DE 10 2019 / 121205 (A1). These pendulum rocker dampers have an input side and an output side, which are connected to one another (in both directions) in a torque-transmitting manner. A number of rocker elements (also called rockers) and a number of spring elements are interposed. The rocker elements are supported in a relatively displaceable manner by at least one rolling element on the input side and / or the output side. The rolling elements are clamped by the spring elements so that they can roll between the respective transmission track and the complementary counter track. The relative torsion angle between the input side and the output side is converted by the pendulum rocker damper into a spring deflection of the spring element. The transmission track and the complementary counter track forming the ramp gear allow the transmission ratio to be adjusted and thus the stiffness of the pendulum rocker damper to be adjusted. Here, the transmission ratio does not have to be constant, but it is also advantageous to be able to variably adjust the slope of the ramp gear via the twist angle from the input side to the output side. A further advantage of such a pendulum rocker damper compared to other embodiments is that it has (almost) no hysteresis characteristics, especially at the zero crossing.

[0038] With the friction device proposed herein, a sufficient constancy of the friction torque characteristic curve for setting the torsional flexibility of the torsional vibration damper or the drive train can be achieved over the desired service life, without requiring additional installation space or additional components for this. Moreover, such a friction device can preferably be combined with a conventional torsional vibration damper as a replacement for a conventional friction device. In addition, the construction and component costs are preferably the same as or even lower than those of conventional friction devices.

[0039] According to a further aspect, a drive train is proposed, comprising at least the following components: at least one engine having a machine shaft; a gear for transmitting the torque of at least one machine shaft to at least one consumer; a torsional vibration damper according to an embodiment according to the above description, wherein at least one engine and at least one consumer are coupled in such a way that torque is transmitted by the torsional vibration damper such that the torque is damped against torsional vibrations.

[0040] The drivetrain is designed to transmit the torque provided by an engine, e.g. an internal combustion engine or an electric engine, delivered via its output shaft to at least one consumer. An exemplary consumer in an automotive application is at least one drive wheel for the propulsion of the vehicle. In one embodiment, multiple engines are provided, e.g. in a hybrid drivetrain, an internal combustion engine and at least one engine, e.g. a motor-generator. By using a torque limiter in the drivetrain, the engine and / or other components of the engine are protected from damage as a result of torque peaks or torque shocks.

[0041] In the case of the drive train proposed herein, in conjunction with a torsional vibration damper (preferably a rocker damper) having a friction device as described herein, a sufficient constancy of the friction torque characteristic curve for setting the torsional flexibility of the drive train can be achieved over the desired service life, without requiring additional installation space or additional components for this. Moreover, such a friction device can preferably be combined with a conventional torsional vibration damper as a replacement for a conventional friction device. In addition, the construction and component costs are preferably the same as or even lower than in the case of a conventional torsional vibration damper having a friction device.

[0042] According to a further aspect, a motor vehicle is proposed, the motor vehicle having at least one drive wheel, which can be driven by a powertrain according to an embodiment according to the above description, for propulsion of the motor vehicle.

[0043] Most modern motor vehicles have front-wheel drive and sometimes the engine, e.g. internal combustion engine and / or electric engine, is arranged transversely to the main direction of movement (longitudinal axis) in front of the driver's cab. In such an arrangement the radial installation space is particularly small, and therefore it is particularly advantageous to use a drivetrain with components of small size. The use of drivetrains in motor-driven two-wheelers is similar, with increasingly higher performance demands compared to previously known two-wheelers with the same installation space. With the hybridization of the drivetrain, this problem is also exacerbated in rear axle arrangements, and here also in both longitudinal and transverse arrangements of the drive machine.

[0044] For the proposed vehicle with a drivetrain as described herein, sufficient constancy of the friction torque characteristic curve for setting the torsional flexibility of the drivetrain can be achieved over the desired service life without requiring additional installation space or additional components. The construction and component costs are preferably the same or even lower than for conventional drivetrains.

[0045] Passenger cars are assigned to vehicle categories depending on, for example, size, price, weight, and performance, and this definition is constantly changing based on market needs. In the US market, vehicles in the small car and microcar categories are assigned to the subcompact car category according to the European classification, while in the UK market they correspond to the superminicar and city car categories, respectively. Examples of the microcar category are the Volkswagen up! or the Renault Twingo. Examples of the small car category are the Alfa Romeo Mito, the Volkswagen Polo, the Ford Ka+, or the Renault Clio. Known hybrid vehicles are the BMW 330e or the Toyota Yaris Hybrid. Known mild hybrids are, for example, the Audi A6 50 TFSI e or the BMW X2 xDrive25e.

[0046] The invention described above will now be explained in detail against the background of the important technical aspects with reference to the attached drawings showing preferred embodiments, in which it is to be noted that the invention is in no way limited by the use of the drawings which are purely schematic, but which are not dimensionally accurate and are not suitable for defining proportions. [Brief description of the drawings]

[0047] [Figure 1] 1 shows an exploded view of a friction device. [Diagram 2] In front view, the first friction disc according to FIG. 1 is shown. [Diagram 3] In the cross section AA according to FIG. 2, the first friction disc is shown. [Figure 4] 1 shows a moving force diagram of the spring stiffness of a friction device. [Diagram 5] 13 shows a force diagram of the spring stiffness of a friction device in a further embodiment; [Figure 6] 1 shows a vehicle having a drivetrain. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] FIG. 1 shows the friction device 1 in an exploded view, with the components shown axially offset relative to each other along a central rotation axis 2. The input side 4 is formed by a first input disc 5 (front left as shown) and a second input disc 6 (rear right as shown), which are here (purely optionally) torque-transmittingly connected to each other by a number of rivets 60. The output side 7 is shown axially central and comprises an energy storage element 8 (here a disc spring) and two friction discs 9, 10. The disc spring 8 is arranged between the first friction disc 9 (as shown to the left in front of the disc spring 8) and the second friction disc 10 (as shown to the right behind the disc spring 8). The disc spring 8 is here rotatably fixed to the friction discs 9, 10 via corresponding suspensions 44, 45, 46, 47, of which the first suspension 44 (of the first friction disc 9), the second suspension 45 (of the second friction disc 10) and the third suspension 46 (of the disc spring 8) are fixed for mutual rotation and indirectly interact with the external teeth of a coupling element (not shown here). Purely optional, a fourth attachment 47 is formed radially on the outside of the disc spring 8 and is accommodated in a corresponding recess 61 of the second friction disc 10 for relative rotational fixation and / or correct pre-assembly. The relative twist angle between the input side 4 and the output side 7 thus leads to a relative twist of the input discs 5, 6 with respect to the friction discs 9, 10, so that the disc spring 8 is carried by the friction discs 9, 10 or directly via said coupling element.

[0049] The disc spring 8 is structurally pretensioned, i.e. by the (effective) axial depth of the corresponding axially spaced input discs 5, 6 and friction discs 9, 10. The disc spring 8 is supported on a third contact area 13 of the second friction disc 10 and introduces a third axial force 19 which the second friction disc 10 transmits via its third friction zone 16 (hidden here) to generate a friction torque on the second counter-friction surface 43 (compare below). The first axial force 17 and the (herein larger) second axial force 18 are transmitted by the disc spring 8 to one of the two (herein covered) contact areas 11, 12 of the first friction disc 9 and are transmitted by the first friction disc 9 via its first friction zone 14 or its second friction zone 15 to a first counter-friction surface 42 (see below) of the first input disc 5.

[0050] The second input disc 6 has a (purely optional, closed) second counter-friction surface 43 that interacts with the (here covered) third friction zone 16 of the second friction disc 10. The first input disc 5 has such a first counter-friction surface 42 formed by a number of radial webs 41. The radial webs 41 are formed between the 40 sector breakouts. In an alternative embodiment, the first counter-friction surface 42 is formed by an axially protruding radial segment of the first input disc 5, the shape of which corresponds to the radial web 41 shown. The shape and extent of the radial web 41 depends on the complementary shape of the first friction disc 9 or its two friction zones 14, 15 and on the ramp-like transition in the direction of rotation, where the ramp transmission is formed. It should be pointed out that in this embodiment, the ramp transmission, which converts the torsion angle into the axial stroke, is formed solely between the first input disc 5 and the first friction disc 9. Alternatively, such a ramp ratio may be formed solely or additionally between the second input disc 6 and the second friction disc 10, as will be described in detail with reference to the first friction disc 9 shown in FIG.

[0051] In the case of the second input disc 6, a first helix angle 20 and a second helix angle 21 are shown, which are understood as (maximum) limit angles starting from the zero position. In this respect, in the area of ​​the first helix angle 20, the first friction zone 14 of the first friction disc 9 is in frictional contact with the first counter-friction surface 42 of the first input disc 5, and in the area of ​​the second helix angle 21 (adjacent to the first helix angle 20), the second friction zone 15 of the first friction disc 9 is in frictional contact with the first counter-friction surface 42 of the first input disc 5.

[0052] FIG. 2 shows the first friction disc 9 according to FIG. 1 in a front view of the side facing the first input disc 5. It can be clearly seen from the lines that determine the radial projection on the surface of the first friction disc 9 that the first friction zone 14 is arranged axially lower than the second friction zone 15 and that a ramp-shaped transition is formed between the friction zones 14, 15 in the direction of rotation. An advantageous embodiment is shown here, in which the ramp-shaped transition in the direction of rotation is superimposed by a radial ramp inclination. This will be described in more detail below with reference to FIG. 3. The cross section AA of FIG. 3 is now displayed. This cut passes through the ramp-shaped transition, so that the first friction zone 14 is cut radially on the inside and the second friction zone 15 is cut radially on the outside.

[0053] In Figure 3 the first friction disc 9 is shown in section AA of Figure 2. Here the surface 35 facing the disc spring 8 (compare Figure 1) is on the left and on the side facing the first input disc 5 shown in Figure 2, the first friction disc 9 is shown on the right. Section AA passes through the ramp-like transition from the first friction zone 14 to the second friction zone 15.

[0054] The disc spring side surface 35 of the first friction disc 9 comprises in this embodiment (purely optional) a first contact area 11 at the first (disc spring side) diameter 27 and also a radially outwardly directed second contact area 12 at the second (disc spring side) diameter 29. Depending on its load, the disc spring 8 is in contact with the first contact area 11 for transmitting the first axial force 17 and / or with the second contact area 12 for transmitting the second axial force 18. For example, until the end of the (range of) the first twist angle 20, only the first contact area 11 is in contact with the disc spring 8, and from the beginning of the (range of) the second twist angle 21, only the second contact area 12 is in contact with the disc spring 8. In one embodiment, during the transition from the first twist angle 20 to the second twist angle 21, the disc spring 8 is in contact with the two contact areas 11, 12 of the first friction disc 9. This situation is given, for example, when the disk spring 8 is on the flat portion 62 .

[0055] According to one embodiment, the disc spring 8 is held in a relaxed or pretensioned position up to the flat portion 62, such that the radially outer edge of the disc spring 8 is in force-transmitting contact with the third contact area 13 (compare FIG. 1) of the second friction disc 10, and is in force-transmitting contact with the radially inner edge of the disc spring 8 with the first contact area 11 of the first friction disc 9. According to this embodiment, the disc spring 8 is held in a tensioned position beyond the flat portion 62, such that the radially inner edge of the disc spring 8 is in force-transmitting contact with the third contact area 13 (compare FIG. 1) of the second friction disc 10, and is in force-transmitting contact with the second contact area 11 of the first friction disc 9, together with the radially outer edge of the disc spring 8. The first friction zone 14 associated with the first contact area 11 is preferably arranged radially on the inside, and the second friction zone 15 associated with the second contact area 12 is preferably arranged radially on the outside.

[0056] The first diameter 28 on the side of the input disc is exemplarily defined here on the inner edge, but must be further outwardly radially when viewed as the average friction zone diameter. The second diameter 30 on the side of the input disc is exemplarily defined here on the outer edge, but must be further inwardly radially when viewed as the average friction zone diameter. In contrast, in an embodiment, the second diameter offset 32 ​​in the second contact area 12 and in the second friction zone 15 is greater than the first diameter offset 31 in the first contact area 11 and in the first friction zone 14. However, the diameter offsets 31, 32 are preferably defined in each case on the indicated diameters 28, 30 on the side of the input disc, i.e. on the outer edge of the radially outer friction zone 15 and on the inner edge of the radially inner friction zone 14.

[0057] In the embodiment shown here (purely optionally), the first distance 33 between the first contact area 11 and the first friction zone 14 or the inner edge of the first friction zone 14 is not equal to the second distance 34 between the second contact area 12 and the second friction zone 15 or the outer edge of the second friction zone 15. In addition, the first height 36 of the first contact area 11 is higher than the second height 37 of the second contact area 12, so that a height difference 63 is set. The second distance 34 is preferably higher than the first distance 33, which is higher than the height difference 63. The first friction disc 9 is therefore thinner on the inner circumference than on the outer circumference or second diameter 29 on the disc spring side. The stiffness of the first friction disc 9 is therefore lower when the disc spring 8 acts on the first contact area 11 than when it acts on the second contact area 12. The series combination of the disc spring characteristic curve 64 and the resilience of the first friction disc 9 results in an increased usable (total) range of travel compared to the usable range of travel of the disc spring 8 alone.

[0058] 4 shows a displacement force diagram in which, with the force axis 65 as the ordinate and the displacement axis 66 as the abscissa, the disk spring characteristic curve 64 (thin dashed line) and the two overall spring forces 22, 23 (continuous straight lines) as well as the overall characteristic curves 67, 68 resulting from the superposition (flat dashed lines rougher than the disk spring characteristic curve 64) are plotted. The disk spring characteristic curve 64 is formed in the form of an inverted parabola to the left and right of the flat portion 62, with a local maximum 69 of the disk spring force being reached before the flat portion 62 and a local minimum 70 being reached after the flat portion 62. A plateau of force is therefore formed approximately around the flat portion 62 around the section of the disk spring characteristic curve 64.

[0059] The usable range of travel 24, 25, 26 between the minimum usable force 38 and the maximum usable force 39 is defined herein (as a result of the installation position) such that the minimum usable force 38 is located at a local minimum 70 of the disc spring characteristic curve 64 (to the right of the flat portion 62).

[0060] The overall elasticity 22, 23 is shown in the displacement force diagram with a (ideally constant) slope, specifically the minimum overall elasticity 22 (stiffness) and the maximum overall elasticity 23. In series combination, this results in a slightly flatter (minimum) overall characteristic curve 67 for the minimum overall elasticity 22 and a significantly flatter (maximum) overall characteristic curve 68 for the maximum overall elasticity 23, compared to the diaphragm spring characteristic curve 64. It should be noted that the magnitudes of the maximum 69 and minimum 70 remain unchanged. Here, the increase in the parabolic section of the overall characteristic curves 67, 68 is significantly flatter than in the case of the disc spring characteristic curve 64. This embodiment of the overall characteristic curves 67, 68 is particularly advantageous when the ratio of the maximum available force 39 [numerator] to the minimum available force 38 [denominator] is greater than 1.5 [1.5], and only the displacement range 24, 25, 26 starting from the minimum 70 (to the right of the flat portion 62) is used (as already mentioned above).

[0061] Figure 5 shows a similar displacement force diagram to Figure 4, to which extent reference is made without excluding generality to the description therein. Here too the usable displacement range 24, 25, 26 between the minimum usable force 38 and the maximum usable force 39 is defined (as a result of the installation position) in such a way that the minimum usable force 38 is still located before (i.e. to the left of) the local maximum 69 of the disc spring characteristic curve 64 (up to the left of the flat portion 62) and the maximum usable force 39 is located after (i.e. to the right of) the local minimum 70 of the disc spring characteristic curve 64 (up to the right of the flat portion 62), as shown in Figure 4. Without excluding generality, the overall spring forces 22, 23 are identical to those in the embodiment shown in Figure 4 purely for clarity, with the same consequences for the change in the disc spring characteristic curve 64 relative to the overall characteristic curves 67, 68.

[0062] This embodiment of the overall characteristic curves 67, 68 is particularly advantageous when the ratio of the maximum usable force 39 [numerator] to the minimum usable force 38 [denominator] is greater than 2 [2], in which case (as already mentioned above) the travel ranges 24, 25, 26 are used to the left and right of the flat portion 62, and completely optionally the flat portion 62 is positioned approximately or exactly in the middle between the minimum usable force 38 and the maximum usable force 39.

[0063] 6 shows, in a schematic top view, a motor vehicle 59 with a drive train 48. The motor vehicle 59 has a longitudinal axis 71 and an engine axis 72, which (completely optional) is arranged here laterally in front of the cab 73. The drive train 48 comprises a first engine 52, which is preferably designed as an internal combustion engine 52 with a first machine shaft 54 ​​(which is then, for example, an internal combustion engine shaft 54), a second (preferably electric) drive machine 53 (here designed as a so-called hybrid module) with a rotor shaft 55, and a transmission 56 (here, for example, a belt transmission [CVT: continuously variable transmission]). The internal combustion engine shaft 54 ​​is torque-transmittingly coupled to the rotor shaft 55 by means of a torque limiter. The rotor shaft 55 is in turn torque-transmittingly coupled to the transmission 56 with the left driving wheel 57 and the right driving wheel 58. The (tractional) torque for the drivetrain 48 can be output by both engines 52, 53 or via their mechanical shafts 54, 55 simultaneously or at different times.

[0064] Thus, the drive wheels 57, 58 can be supplied with a (preferably variable) transmission by the drive machines 52, 53. However, torque can also be absorbed by the internal combustion engine 52, for example for engine braking, and by the electric machine 53 for brake energy recovery. By the torsional vibration damper 3 (embodied here for example as a rocker damper 51) with an input element 49, an output element 50 and a friction device 1 (not shown), the electric drive machine 53 (on the internal combustion engine side) is protected from system-related rotational irregularities, since these are smoothed out. The input element 49 is for example a flange disk, and the output element 50 is for example another flange disk. In this case, the series combination of the torsional vibration damper 3 and the friction device 1 is designed to be almost neutral in terms of installation space, and in addition different damping characteristics are set depending on the torque level, which on the one hand is almost dissipative in the pendulum rocker damper 51 and on the other hand dissipatively depends on the obtained torsion angles 20, 21 by the friction device 1. Thus, for example, a desired (variable) hysteresis characteristic of the torsional vibration damper 3 is set.

[0065] With the friction device proposed herein, the usable range of motion is increased without requiring additional installation space or additional components. [Explanation of symbols]

[0066] 1 Friction device 2 Rotation Axis 3 Torsional vibration damper 4 Input side 5 First Input Disk 6 Second Input Disk 7 Output side 8 Energy Storage Elements 9 First Friction Disc 10 Second Friction Disc 11 First Contact Area 12 Second Contact Area 13 Third Contact Area 14 First Friction Zone 15 Second Friction Zone 16 The third friction zone 17 First Axial Force 18 Second Axial Force 19 Third Axial Force 20 First twist angle 21 Second twist angle 22 Minimum overall elasticity 23 Maximum overall elasticity 24 Usable range of movement (disc spring) 25 Minimum usable range of movement 26 Maximum usable range of movement 27 First disc spring side diameter 28 First input disc diameter 29 Second disc spring side diameter 30 Second input disc diameter 31 First Diameter Offset 32 Second Diameter Offset 33 First Distance 34 Second Distance 35 Surface of first friction disc 36 First Height 37 Second Height 38 Minimum usable force 39 Maximum usable power 40 Sector Breakout 41 Radial Bar 42 First anti-friction surface 43 Second anti-friction surface 44 First Suspension 45 Second Suspension 46 Third Suspension 47 Fourth Suspension 48 Drivetrain 49 Input Elements 50 output elements 51 Pendulum Rocker Damper 52 Internal Combustion Engine 53 Electrically Driven Machines 54 Internal combustion engine shaft 55 rotor shaft 56 Transmission 57 Left driving wheel 58 Right drive wheel 59 Automobiles 60 Rivet 61 Recess 62 Flat area 63 Height Difference 64 Disc spring characteristic curve 65 force axis 66 Moving axis 67 Minimum overall characteristic curve 68 Maximum overall characteristic curve 69 Maximum 70 Minimum 71 Longitudinal axis 72 Engine shaft 73 Cab

Claims

1. A friction device (1) having a rotating shaft (2) for a torsional vibration damper (3), comprising at least the following components: an input side (4) having a first input disc (5) and having a second input disc (6), said first input disc (5) and said second input disc (6) being coupled to one another; an output side (7) having an energy storage element (8), a first friction disc (9) and a second friction disc (10), the energy storage element (8) is arranged axially between the first and second friction discs (9, 10), the first and second friction discs (9, 10) having a plurality of contact areas (11, 12, 13) on the side of the energy storage element and a plurality of friction zones (14, 15, 16) on the side of the input disc, Torque can be transmitted by friction between the input side (4) and the output side (7) with the energy storage element (8) being pretensioned to apply an axial force (17, 18, 19), which axial force (17, 18, 19) is in each case at least one of the contact areas (11, 12, 13) of the energy storage element (8) on the respective first and second friction discs (9, 10), and in each case via at least one of the friction zones (14, 15, 16) of the first and second friction discs (9, 10) on the respective corresponding input disc (5, 6), A relative torsion angle (20, 21) about the rotation axis (2) is created between the output side (7) and the input side (4) as a result of a torque gradient, said torsion angle (20, 21) being: - the amount of axial force (17, 18, 19), and - dependent on the contact areas (11, 12, 13) and / or the friction zones (14, 15, 16) to which the axial forces (17, 18, 19) are transmitted, In said first friction disc (9), a first one of said contact areas (11) and a first one of said friction zones (14) are each arranged on a first diameter (27, 28), and a second one of said contact areas (12) and a second one of said friction zones (15) are each arranged on a second diameter (29, 30), at least one of said first diameters (27, 28) being different from said respective equilateral second diameters (29, 30), Friction device (1), characterized in that a first axial distance (33) between the first contact area (11) and the first friction zone (14) is different from a second axial distance (34) between the second contact area (12) and the second friction zone (15).

2. Friction device (1) according to claim 1, wherein the first friction zone (14) and the second friction zone (15) merge into one another in the circumferential and radial directions in the form of a ramp.

3. the first contact area (11) and the second contact area (12) protrude from a surface (35) of the associated friction disc (9) facing the energy storage element (8) at different heights (36, 37), 3. Friction device (1) according to claim 1 or 2, wherein at least one of the contact areas (11, 12, 13) is formed so as to be dome-shaped.

4. At least one of the input discs (5) has sector breakouts (40) and radial webs (41) between the sector breakouts (40); the counter-friction surface (42) of the friction zone (14, 15) of the corresponding friction disc (9) is formed by the radial web (41), the radial webs (41) have a web elasticity in which a major part of the predetermined overall elasticity (22, 23) in the axial direction is formed, Friction device (1) according to any one of claims 1 to 3, wherein the web elasticity is variable depending on the effective abutment diameter (28, 30) of the corresponding friction zone (14, 15).

5. The friction discs (9, 10) are arranged such that a torque is transmitted through the suspensions (44, 45) of the friction discs (9, 10) which are effective in the direction of rotation. - has a separate coupling element arranged for a torque-transmitting coupling to said output side (7), and / or - A friction device (1) according to any one of claims 1 to 4, which are connected to one another.

6. 6. The friction device (1) according to claim 1, wherein the energy storage element (8) is coupled to one of the friction discs (10) in a torque-transmitting manner via a suspension (46, 47) of the energy storage element (8) that is effective in the direction of rotation.

7. A torsional vibration damper (3) for a drivetrain (48) comprising an input element (49) and an output element (50) and a friction device (1) according to any one of claims 1 to 6, wherein the input element (49) is coupled to the output element (50) by the friction device (1) in a dissipatively damped torque transmitting manner, The torsional vibration damper (3), wherein the torsional vibration damper (3) is designed as a pendulum rocker damper (51).

8. A drive train (48) comprising at least the following components: at least one drive machine (52, 53) having a machine shaft (54, 55); a transmission (56) for transmitting the torque of said at least one machine shaft (54, 55) to at least one consumer (57, 58); - a torsional vibration damper (3) according to claim 7, wherein the at least one driving machine (52, 53) and the at least one consumer (57, 58) are coupled in such a way that torque is transmitted by the torsional vibration damper (3) such that the torque is damped against torsional vibrations.

Images