CN112065940A - Traction means tensioning device for a traction means drive - Google Patents

Abstract

The invention relates to a traction means tensioning device (1) for a traction means drive (2), comprising at least the following components: at least one tensioning roller (3, 4) for rolling on a traction means (5) of the traction means drive (2); and at least one tensioning means (6) for pre-tensioning the tensioning roller (4) against such a traction means (5). The traction means tensioning device is characterized in that the traction means tensioning device (1) further comprises a torsional vibration damper (6) having an input side (7) and an output side (8), and the at least one tensioning roller (4) is damped by means of the torsional vibration damper. The tensioning device for the traction means proposed here makes it possible to achieve a low prestress over-height in the new state.

Description

Traction means tensioning device for a traction means drive

Technical Field

The invention relates to a traction means tensioning device for a traction means drive, a traction means drive with such a traction means tensioning device for a drive train, a drive train with such a traction means drive and a motor vehicle with such a drive train.

Background

In motor vehicles with hybrid drive trains, it is known to connect the internal combustion engine to a starter generator by means of a belt drive (so-called belt starter generator). Such a Hybrid drive train is known, for example, as P0 Mild Hybrid (P0-Mild-Hybrid). On the one hand, starter generators are conventionally driven by means of a belt drive for generating electrical energy from an internal combustion engine. On the other hand, the starting torque is transmitted by means of a belt to the burner shaft of the internal combustion engine by means of a belt starter generator. At start-up, the burner shaft is subjected to an unfavorable vibration frequency, which is suitable for decoupling the belt starter generator at least when it is in load operation. It is known to provide a pulley decoupler, which comprises a torsional vibration damper, for example a dual mass flywheel, into a belt drive, for example the rotor shaft of a belt starter generator. The torsional vibration damper is integrated into the belt pulley between the input side (e.g. belt receiving section) and the output side (e.g. shaft coupling). In belt drives, belt tensioners are also conventionally provided which are pretensioned against the belt by means of at least one tensioning roller, so that the belt has a (almost) constant pretensioning force. For this purpose, tensioning springs are used, for example in a belt tensioner with two tensioning rollers, for arrangement around the rotor shaft of a belt starter generator by means of bow springs.

The necessary pretensioning force should be achieved in a belt pulley tensioner, wherein, however, at the end of the service life of the belt drive (which is usually the same as the service life of the vehicle), a high pretensioning force must still be maintained in order to avoid severe belt slip. In general, due to geometric tolerances and a given spring stiffness, a significantly higher prestress in the new state results. This higher pretension results in a higher belt tension than necessary and also in a higher fuel consumption of the internal combustion engine due to increased friction and axial transverse loads.

Disclosure of Invention

On this basis, the invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features according to the invention are given in the description, in which advantageous configurations are listed. The features according to the invention can be combined in any technically expedient manner, wherein for this purpose reference can also be made to the features set forth in the description below and in the drawings, which comprise additional configurations of the invention.

The invention relates to a traction means tensioning device for a traction means drive, comprising at least the following components:

-at least one tensioning roller for rolling on the traction means of the traction means drive; and

-at least one tensioning means for pre-tensioning the tensioning roller against such traction means.

The traction means tensioning device is characterized in that it further comprises a torsional vibration damper having an input side and an output side, and the at least one tensioning roller is damped by means of the torsional vibration damper.

In the following, reference is made to the mentioned axis of rotation if "axial", "radial" or "circumferential direction" and corresponding terms are used without further explicit indication. Ordinal terms used in the foregoing and following description are used only for explicit distinction and do not indicate a sequence or order of the components unless otherwise explicitly indicated. Ordinal numbers greater than one do not imply that additional such elements are necessarily present.

The traction means tensioning device proposed here is provided for tensioning a traction means drive for a hybrid drive train, for example, having an internal combustion engine and a belt starter generator. The traction means drive is, for example, a belt drive, for example with a wedge belt, or a chain drive. For this purpose, the traction means tensioning device has at least one tensioning roller, for example two tensioning rollers, which roll passively on the traction means, for example a wedge belt. The at least one tensioning roller is pretensioned against the traction means of the traction means transmission by means of tensioning means, so that a desired tensioning means tension is generated corresponding to the force of the tensioning means. At least one of the tensioning rollers, at least the movably prestressed tensioning roller or the respective roller axis of the tensioning roller is held on a tensioning arm which is embodied so as to be movable, preferably pivotable about a center, at the damping tensioning roller in such a way that the tensioning means is deflected in the process. The tensioning arm, which is subjected to vibration damping, is thus pretensioned against the traction means by means of the tensioning means.

It is now proposed that the traction means tensioning device also comprises a torsional vibration damper, so that the traction means tensioning device can also be referred to as a traction means decoupling tensioner. Torsional vibration dampers are known, for example, from the use in torque transmission systems. The torsional vibration damper is conventionally provided for transmitting a torque, wherein torsional vibrations, for example, caused by ignition in an internal combustion engine as a torque source are damped. Therefore, it is possible to protect downstream components and reduce noise emissions. For this purpose, the torsional vibration damper has an input side and an output side. However, torsional vibration dampers are not conventionally used here. Rather, the torque is not transmitted, but at least one component of the torsional vibration damper is fixed. The torsional vibration damper is provided here for achieving the most stationary possible position of the at least one tensioning roller using the fastening as a bearing. The vibrations of the at least one tensioning roller (caused by the traction means) thus act (anarbeiten) on the bearing via the torsional vibration damper. It should be noted here that the torsional vibration damper damps only such string-like vibrations of the traction means, i.e. vibrations having an amplitude which is translatory or radial relative to the direction of the loop of the traction means or formed by said traction means. The (pure) traction force fluctuations lead to rotational speed fluctuations at the tensioning roller and thus at most indirectly to a damping effect of the torsional vibration damper.

In one embodiment, the input side is fixed, for example, to the engine housing. In this case, the traction means can be damped exclusively by means of the output side of the torsional vibration damper. In a further embodiment of the traction means tensioning device, the input side is connected to the first tensioning roller and the intermediate element of the torsional vibration damper (e.g. the spring stop and/or the pendulum element) is fixed, for example to the engine housing. The vibration of the traction means can then be damped not only by means of the input side of the torsional vibration damper but also by means of the output side of the torsional vibration damper.

The damping tensioning roller, i.e., at least the output-side (second) tensioning roller, bears with a bias against the traction means and thus deflects the traction means. If the traction means tension increases due to traction means vibrations, the damping tensioning roller must be deflected. The torsional vibration damper acts counter to its pretensioning force, so that the vibration behavior changes, i.e., the natural frequency of the traction means transmission is shifted, so that, when the traction means transmission is operating according to design, the friction forces at the (driven and driven) traction means disk do not decrease excessively and no severe slipping occurs.

It should be noted that even in conventional belt tensioners, damping effects occur in the tensioning device and are used in part in a targeted manner. However, these damping effects are much smaller than torsional vibration dampers (also referred to as rotational vibration dampers), so that the damping device cannot be referred to as torsional vibration dampers. In particular in conventional belt tensioners, this damping effect is not torsional, i.e. not directed against the torque, but directly on the pretensioning displacement of the associated tensioning roller. In the present context, torsional vibration dampers are to be understood more precisely as individual structural components known to the person skilled in the art and/or as damping means which are connected in the torque transmission train. Such damping means are provided for the efficient transmission of torque, wherein, in normal use, the input side and the output side rotate upon torque transmission (neglecting the superimposed torsional synchronization to be damped). Torsional vibration dampers do not act or do not act solely by means of friction effects. The torsional vibration damper comprises a flywheel mass and/or means for varying, preferably reducing, the natural frequency of the damped system, for example by means of an energy storage element with a varying, preferably smaller (effective) stiffness connected in between.

In addition, in an advantageous embodiment of the traction means tensioning device, it is provided that the tensioning means is formed by a torsional vibration damper.

In this embodiment, it is proposed that the tensioning element of the traction means tensioning device is formed by the torsional vibration damper itself, so that, for example, a bow spring conventionally provided in a belt tensioner can be dispensed with. For damping vibrations, the torsional vibration damper comprises in an integrated manner at least one energy storage element, for example at least one helical compression spring. In this case, the torsional vibration damper is not supported by itself as in the conventional use of the torsional vibration damper (for example in torque operation), but at least the tensioning roller on the output side of the torsional vibration damper forms a vibration absorber for the at least one energy storage element of the torsional vibration damper. The at least one energy storage element is mounted in a fixed manner on a fixed part of the traction means tensioning device. For example, the input side of the torsional vibration damper is fixed, for example on the engine housing, so that in an embodiment with two tensioning rollers, the other (for example the first) tensioning roller is fixed or its holder forms a seat for the at least one energy storage element. In this case, the first tensioning roller, like the (pure) deflecting roller, is prestressed against the traction means during operation of the traction means by means of a geometric configuration (for example, set during assembly), and the second tensioning roller is prestressed against the traction means by means of at least one energy storage element of the torsional vibration damper.

In an alternative embodiment with two tensioning rollers, the first tensioning roller is connected to the input side of the torsional vibration damper and the second tensioning roller is connected to the output side of the torsional vibration damper, wherein the input side and thus the first tensioning roller is not fixed. More precisely, an intermediate element (e.g., a spring stop and/or a pendulum element) of the torsional vibration damper is fixed. In this case, both the input side and the output side of the torsional vibration damper can be freely moved, so that both the first tensioning roller and the second tensioning roller are prestressed by means of at least one energy storage element of the torsional vibration damper.

In an advantageous embodiment of the traction means tensioning device, it is furthermore proposed that the torsional vibration damper is a wobble damper

In this embodiment, the torsional vibration damper is designed as a wobble damper, in which the at least one energy storage element is connected in a driven manner to the output side of the torsional vibration damper by means of a wobble (wippendel) and at least one roller, which together form a so-called roller or cam drive (Kurvengetriebe). The advantage of such a wobble damper is primarily that the at least one energy storage element can be embodied with a (almost arbitrary) high stiffness, while at the same time torsional oscillations are caused by the significantly reduced stiffness due to the transmission ratio of the roller gear. This is achieved by: a large (first) deflection displacement of the at least one tensioning roller, for example a pivoting movement of a tensioning arm, is converted into a reduced (second) deflection displacement of the at least one energy storage element by means of the wobble. This is achieved by: the slope at the point of oscillation for the at least one roller is embodied such that (as large a first deflection displacement as possible, for example a pivot angle) a conversion is made into a second deflection displacement of the energy storage element which is as short as possible. Thus, despite the (excessive) stiffness of the energy storage element, a reduced effective stiffness of the energy storage element is obtained at the tensioning roller performing the damping due to the long roller displacement. However, only when vibrations of the traction means occur does the wobble describe the relative movement and only this conversion takes place. In addition to this, the entire rigidity of the energy storage element is effective at the at least one damping tension roller.

Due to the high stiffness of the at least one energy storage element that can be used in the pendulum damper, the excess of the pretensioning force in the new state can be reduced, since the (e.g. displacement-dependent) compression phenomena are reduced.

According to another aspect, the at least one energy storage element relaxes due to wear and aging. The stiffness is therefore reduced relative to the new state of the traction means, so that the pretension is reduced and the vibration damping is changed. According to a further aspect, the wobble damper is arranged such that the transmission ratio is changed by a reduction in the stiffness of the at least one energy storage element caused by the relaxation, such that this reduction in stiffness is at least partially, preferably largely, compensated. For this purpose, in this embodiment, the reduction in the transmission ratio is set with increasing deflection, so that the reduction in the stiffness of the at least one energy storage element is partially (preferably almost completely) compensated. In addition, the excess amount of pretension in the new state can thus be reduced. In this embodiment, the transmission ratio profile of the roller gear of the wobble damper is preferably not linear over the (first) deflection displacement, but is preferably continuous.

In addition, in an advantageous embodiment of the traction means tensioning device, it is provided that the traction means tensioning device has a first tensioning roller and a second tensioning roller which are provided for rolling on the traction means and can be pretensioned against such a traction means by means of a tensioning means, wherein the first tensioning roller is arranged on the input side of the torsional vibration damper and the second tensioning roller is arranged on the output side of the torsional vibration damper.

In this embodiment, two tensioning rollers are provided, which are each prestressed against the loop formed by the traction means, for example from the radially outer side. The first of the two tensioning rollers is arranged here on the input side of the torsional vibration damper, and the second of the two tensioning rollers is arranged on the output side of the torsional vibration damper, each of which is arranged, for example, by means of a tensioning arm. In a preferred embodiment, the input side of the torsional vibration damper is fixed, for example, to the engine housing. The second tensioning roller is then suspended movably with the output side (damped). In one embodiment, in which the torsional vibration damper is embodied as a wobble damper, the output side is connected to at least one energy storage element by means of a roller gear, wherein the energy storage element is supported on the input side. The output side then forms a tensioning arm which leads to the second tensioning roller and at which the roller axis of the second tensioning roller is prestressed movably, preferably pivotably, against the traction means. In the fixed embodiment, the first tensioning roller is geometrically prestressed against the traction means, while when the input side is not fixed, the first tensioning roller is prestressed directly (or by means of a corresponding tensioning arm) by the energy storage element of the wobble damper. In this embodiment, for example, the wobble of the wobble damper is fixed, for example, on the engine housing.

According to a further aspect, a traction means transmission for a drive train is proposed, which has at least the following components:

-a first traction means disc for connection with a drive shaft of a drive machine;

-a second traction means disc for connection with a rotor shaft of an auxiliary unit; and

a traction means connecting the first traction means disk and the second traction means disk in a torque-transmitting manner,

wherein the traction means is tensioned by means of a traction means tensioning device according to any of the embodiments described above.

The traction means drive proposed here is, for example, a P0 mild hybrid belt drive provided for starting an internal combustion engine, which belt drive comprises the internal combustion engine (drive machine) (to be started) and a belt starter generator (to be started). However, applications outside the motor vehicle sector are also possible, for example in mobile internal combustion engines. The auxiliary group is provided for converting torque into electrical energy or other power, for example an air conditioning compressor provided for compressing (air conditioning) gas. In one embodiment, the auxiliary group as starter generator can also be operated in reverse as a starting device, which outputs its torque to the internal combustion engine by means of the traction means transmission.

The first traction means disk is connected to the drive shaft of the drive machine (for example, an internal combustion engine), and the second traction means disk is connected to the rotor shaft of the auxiliary unit. Optionally, a third traction means disk or more traction means disks are provided at one or more further auxiliary assemblies. The traction means tensioning device is provided for tensioning the traction means, preferably arranged directly on the second traction means disk in such a way that it acts on the traction means with two tensioning rollers, in order to thus adjust a large winding angle at the second traction means disk, which winding angle is increased by the traction means tensioning device as the tension in the traction means decreases. This is achieved by: at least one of the tensioning rollers is movable in a circulating manner relative to the second traction means disc, for example pivotable (approximately or exactly) about a (second) disc axis. For example, the pivot center of the traction means tensioning device coincides for this purpose with the second disk axis or the (rotor) axis of the rotor shaft. Since the traction means tensioning device comprises a torsional vibration damper, in addition to the pure tensioning function of the traction means tensioning device, the chordal vibration of the traction means, i.e. the vibration having an amplitude in the translational (or radial) direction relative to the tensioning means (tensioning means loop), is also damped and/or the chordal jump of the traction means caused by resonance due to the (according to the design) delayed reaction of the at least one tensioning roller can be suppressed.

In one embodiment, at least one of the traction means discs is designed as a pulley decoupler, so that both translational, i.e. string-like, vibrations of the traction means and also traction force vibrations, i.e. vibrations in the direction of operation of the traction means, can be damped and the shafts can be decoupled from one another in terms of vibrations.

In a preferred embodiment, the traction means tensioning device comprises a torsional vibration damper, which is embodied as a wobble damper, preferably as a tensioning means for at least one of the two tensioning rollers. A cam gear is provided in the wobble damper in such a way that a reduction in the rigidity (caused by displacement) of the at least one energy storage element is at least partially compensated for by means of a drive cam of the cam gear. Both measures make it possible to reduce the excess of pretension in the new state (which excess serves to maintain sufficient pretension in the old state (altmustine)).

According to another aspect, a drive train is proposed, which has at least the following components:

-a driver machine having a drive shaft;

-an auxiliary assembly with a rotor shaft; and

a traction means transmission according to any one of the embodiments described above, by means of which the drive machine and the auxiliary unit are connected to each other in a torque-transmitting manner.

The drive train is provided for transmitting a torque for at least one consumer, which is provided by a drive machine (for example an internal combustion engine or an electric drive) and is output via its drive shaft. In the case of use in a motor vehicle, an exemplary consumer is at least one drive wheel for the drive of the motor vehicle (e.g., a motorcycle) and additionally an auxiliary unit, for example, a generator for providing electrical energy. In one embodiment, a plurality of drive machines are provided, for example an internal combustion engine and at least one electric machine, for example an electric motor-generator, preferably a starter generator, in a hybrid drive train. Such an electric motor-generator forms, for example, an auxiliary assembly and is provided not only for receiving torque (for generating electrical energy) but also for outputting torque (for boosting and as a starter generator also for starting the internal combustion engine). The traction means transmission enables torque to be transmitted between the auxiliary unit and the drive machine, wherein the string-like vibrations of the traction means are damped by means of the traction means tensioning device. The torque receiver, for example, the (second) traction means disk of the auxiliary assembly, is thereby protected against severe slipping, i.e., the transmission of torque (or traction forces in the traction means) from the first traction means disk to the second traction means disk and vice versa is not affected. In a preferred embodiment, the torsional vibration damper is embodied as a wobble damper and the rigidity of the tensioning means of the traction means tensioning device is increased in comparison with conventional tensioning means (e.g. bow springs). In a preferred embodiment of the torsional vibration damper in the form of a wobble damper, a cam mechanism is provided, so that a reduction in the rigidity (caused by displacement) of the at least one energy storage element is at least partially compensated for by means of a drive cam of the cam mechanism. Both measures make it possible to reduce the excess of pretension in the new state (which excess serves to maintain sufficient pretension in the old state).

Furthermore, the installation space required for the traction means drive proposed here is not excessively increased or even has conventional structural dimensions compared to conventional traction means tensioners. The traction means tensioning device can therefore alternatively be used in a conventional traction means drive without other necessary changes.

According to a further aspect, a motor vehicle is proposed, which has at least one drive wheel which can be driven by means of a drive train according to any of the embodiments described above.

Most motor vehicles have one or more drive motors (e.g., internal combustion and/or electric drive motors) in front of or behind the cab and transverse or longitudinal to the main direction of travel of the motor vehicle. At unfavorable oscillation frequencies (in supercharged internal combustion engines with a low number of cylinders) high running stability and a high torque transmission are required. Fluctuations in the tension of the traction means cause translational, i.e. chordal, oscillations of the traction means, which can therefore lead to severe slipping at the traction means disks. In particular, in so-called belt starters, for example for automatic start-stop, the drive shaft of the internal combustion engine is accelerated by the traction means from a standstill to at least the required ignition rotational speed (e.g. idle rotational speed), and large fluctuations in the tension of the traction means occur in this case.

In the motor vehicle proposed here with the drive train described above, a high efficiency is achieved due to the high running stability and the very constant belt tension, by integrating a very effective torsional vibration damper into the traction means tensioning device of the traction means transmission of the drive train. At the same time, the required installation space is at least no greater than that conventionally used and the costs are not increased compared to conventional vibration-decoupled systems.

Passenger vehicles are assigned vehicle classes according to, for example, size, price, weight and power, wherein this definition is subject to constant variation according to market demand. Vehicles of the small-sized vehicle and the mini-vehicle class classified according to europe are assigned to the class of the sub-compact vehicle (Subcompact Car) in the us market, and they correspond to the super mini (Supermini) class or the City Car (City Car) class in the uk market. An example of such a mini car class is Volkswagen up! Or Renault Twongo. Examples of such mini-car classes are Alfa Romeo Mito, Volkswagen Polo, Ford Ka +, or Renault Clio. The known full Hybrid type in the small car class is BMW i3 or Toyota Yaris Hybrid.

Drawings

Hereinafter, the above invention is explained in detail in the related art background with reference to the accompanying drawings showing preferred configurations. The invention is not in any way restricted to the purely schematic drawing, in which it should be noted that the drawing is not dimensionally exact and is not suitable for defining dimensional proportions. The figures show:

FIG. 1: a traction means drive having a traction means tensioning device;

FIG. 2: a top view of the traction device tensioner;

FIG. 3: side view of the traction means tensioner according to fig. 2 with a belt starter generator;

FIG. 4: top view of the traction means tensioning device according to fig. 2 and 3 without the front plate; and

FIG. 5: a motor vehicle having a drive train with a traction means transmission.

Detailed Description

Fig. 1 schematically shows a traction means drive 2 having a first traction means disk 11 which is rotatable about a first disk axis 31, a second traction means disk 12 which is rotatable about a second disk axis 32, and a third traction means disk 13 which is rotatable about a third disk axis 33. In the second traction means disk 12, a traction means tensioning device 1 is provided, which acts on the traction means 5 tensioned to the traction means disks 11, 12, 13 with a first tensioning roller 3 rotatable about a first roller axis 29 and a second tensioning roller 4 rotatable about a second roller axis 30. The traction means 5 is therefore tensioned as constantly as possible or is able to transmit torque or traction as constantly as possible. In this embodiment, the tensioning rollers 3, 4 are pivotably arranged in such a way that the winding angle at the second traction means disc 12 increases as the pulling tension in the traction means 5 decreases due to at least one of the two tensioning rollers, preferably only the second tensioning roller 4, pivoting inward. For example, the center of the pivoting movement of the at least one tensioning roller 4 coincides with the second disc axis 32.

Fig. 2 shows a schematic top view of an embodiment of a traction means tensioning device 1. The (second) traction means disk 12 is shown in the center in a simplified manner, with its (second) disk axis 32. The traction means disk 12 is guided only through the traction means tensioning device 1 and does not act on the component. In one embodiment, the traction means disk 12 is arranged next to the traction means tensioning device 1. The disk axis 32 is here (optionally) the pivot center of the second tensioning roller 4. The first tensioning roller 3 is here embodied fixedly in the form of a pure deflecting roller. For this purpose, the first tensioning arm 27, on which the first tensioning roller 3 is arranged so as to be rotatable about the first roller axis 29, is fixed to the front plate 35, which is fixed to the rear plate 34 (optionally) by means of a rivet 36 or a pin fixing (only one of the four illustrated pins is here indicated in a dotted and planar manner). The rear plate 34 is in turn (optionally) fixed to a fixed component, for example an engine housing (not shown here), by means of a screw connection 37 (only one of the four screws shown here is indicated in a dot-and-dash manner). In addition, a second tensioning arm 28 can be seen, on which the second tensioning roller 4 is arranged in a rotatable manner about a second roller axis 30. As mentioned above, the second tensioning arm 28 can be pivoted, for example, about the disk axis 32. A torsional vibration damper with an input side 7 and an output side 8 is provided as the tensioning means 6, wherein the torsional vibration damper is embodied here as a wobble damper 9. In this case, only the first energy storage element 21 and the second energy storage element 22 can be seen from the oscillating damper 9. These energy storage elements are supported at the input side 7. The input side 7 of the rocking damper 9 is formed by a rear plate 34, a front plate 35 and a first tensioning arm 27. The output side 8 of the wobble damper 9 is formed by a second tensioning arm 28. The energy storage elements 21, 22 are connected in parallel to one another and are tensioned between the input side 7 and the output side 8 or the intermediate element. The intermediate elements are explained in detail below in fig. 3 and 4.

Fig. 3 shows a side view of the traction means tensioning device 1 as shown in fig. 2, which is flanged to an auxiliary unit 17, which is embodied, for example, as a belt starter generator. In this respect reference is made to the preceding description. The fastening of the rear plate 34 by means of the screw connection 37 and of the front plate 35 (and thus of the first tensioning arm 27) by means of the fastening (optionally embodied as a rivet 36) can be clearly seen here. Thus forming the input side 7 of the torsional vibration damper. The energy storage elements 21, 22 (only the first energy storage element 21 can be seen here) are supported on the input side 7 and are supported opposite one another (depending on the direction of deflection) on the wobble 23, 24. The rockers 23, 24 are connected via rocker rollers 25, 26 (not visible here) to a second tensioning arm 28, so that the second tensioning arm 28 is formed in a pivotable manner, for example pivotable about a (second) disk axis 32 of the (second) traction means disk 12. The pretensioning force of the energy storage elements 21, 22 is thus transmitted to the second tensioning arm 28, and the wobble damper 9 forms the tensioning means 6 of the traction means tensioning device 1, which thus acts on the traction means 5 (with the second tensioning roller 4), for example, as shown in fig. 1.

Fig. 4 shows the traction means tensioning device 1 according to fig. 2 and 3, wherein the plan view corresponds to the illustration in fig. 2, wherein the front plate 35 is not shown here for the sake of clarity. The output side 8 can thus be seen. It should be noted that the wobble damper 9 shown in fig. 4 or its output side 8 represents only one possible embodiment. For example, a wobble damper 9 can be used which has more than one wobble roll 25, 26 for each wobble 23, 24, for example two or three wobble rolls 25, 26 with or without a positive guide for the respective wobble 23, 24 and/or only a single wobble or a plurality of, for example three wobbles. In addition, a plurality of, for example three, energy storage elements can be used or only a single energy storage element can be used. The output side 8 comprises at least one wobble, here a first wobble 23 and a second wobble 24, against which at least one energy storage element 21, 22 is tensioned, or the wobbles 23, 24 work against the energy storage elements 21, 22. In this particular embodiment, when the rockers 23, 24 are deflected in the clockwise direction, the first rocker 23 acts against the second energy storing element 22 and the second rocker 24 acts against the first energy storing element 21. When the swings 23, 24 deflect in the anti-clockwise direction, the first swing 23 works against the first energy storing element 21 and the second swing 24 works against the second energy storing element 22. Instead, only a single operating direction is predefined, and the energy storage elements 21, 22 are permanently tensioned between the input side 7 and the associated wobble 23, 24. The vibration-induced unloading of the energy storage elements 21, 22 (even so) always remains below the relaxed structural length of the respective energy storage element 21, 22. The second tensioning arm 28 is connected to the at least one wobble 23, 24 only by means of at least one wobble roll, in this case by means of (single) wobble rolls 25, 26. The pivot rollers 25, 26 each roll on a curve pair, which together define a transmission ratio profile between the second tensioning arms 28. The pair of bends has, for example, a first rolling track for the respective pendulum roller 25, 26 at the second tensioning arm 28 (in relation to the second disk axis 32) radially on the outside. The wobble 23, 24 has a complementary second rolling track for the respective wobble roller 25, 26 radially on the inside (relative to the second disk axis 32), respectively. Due to the set slope of the rolling path, a wobbling motion or a motion opposite to the compression stroke of the respective energy storage element 21, 22 is generated. In this case, the angle of rotation of the second tensioning roller 4 of the second tensioning arm 28 or the length of the pivot path (at the maximum radius of the energy storage elements 21, 22) differs from, preferably is longer than, the corresponding compression stroke of the associated energy storage elements 21, 22. The transmission ratio is thus set. When the pivot track is longer than the compression stroke, the stiffness acting at the tension roller decreases. For example, in a conventional belt tensioner with a bow spring, the length of the pivot track (at the radius of the bow spring) of the associated tensioning arm corresponds to the compression stroke. It should be noted, however, that such a transmission ratio is not absolutely necessary. Preferably, however, the transmission ratio is not constant, preferably not linear, over the compression stroke, but is provided to compensate for the loss of stiffness of the tensioning means 6 (here the energy storage elements 21, 22) as a function of aging and/or wear characteristics (e.g. empirically determined) of the traction means 5. The excess pretensioning force in the new state can thus be reduced particularly effectively.

Fig. 5 shows a motor vehicle 18 with a (e.g. main) drive machine 15, which is illustrated here as a three-cylinder internal combustion engine, for example, with a drive shaft 14, in the case of which the traction means drive 2 transmits torque to a first auxiliary group 17, for example a belt starter generator, with a rotor shaft 16 and here (optionally) to a second auxiliary group 38, for example an air conditioning compressor. The drive machine 15 and, if necessary, the first auxiliary aggregate 17 are arranged for outputting torque to the left and right drive wheels 19, 20, for example in a conventional manner. This is not elaborated here. The traction means transmission 2 is formed in that the drive shaft 14 is connected to one another by means of a first traction means disk 11, the rotor shaft 16 by means of a second traction means disk 12 and the second auxiliary aggregate 38 by means of a third traction means disk 13 via the traction means 5 in a torque-transmitting manner. In this case (optionally), a traction means tensioning device 1 is provided in the case of the second traction means disk 12, from which, for example, parts of the first tensioning roller 3 and the second tensioning roller 4 can be seen. The components of drive train 10 are arranged here with engine axis 39 transverse to longitudinal axis 40 of motor vehicle 19 and (at the front axle) in front of cab 41. Both of these are selectable independently of one another, i.e. the arrangement of the engine axis 39 parallel to the longitudinal axis 40 and at the rear axle are also selectable.

With the traction means tensioning device proposed here, a low excess of the pretensioning force in the new state can be achieved.

List of reference numerals

1 tensioning device for traction means

2 traction device transmission mechanism

3 first tensioning roller

4 second tension roller

5 traction device

6 tensioning device

7 input side

8 output side

9 swing type shock absorber

10 drive train

11 first traction device disc

12 second traction device disc

13 third traction device disc

14 drive shaft

15 driving machine

16 rotor shaft

17 first auxiliary unit

18 motor vehicle

19 left driving wheel

20 right driving wheel

21 first energy storage element

22 second energy storage element

23 first rocking

24 second rocking

25 first oscillating roller

26 second oscillating roller

27 first tensioning arm

28 second tensioning arm

29 first roll axis

30 second roll axis

31 first disc axis

32 second disc axis

33 third disc axis

34 back plate

35 front plate

36 riveting part

37 screw connection

38 second auxiliary group

39 engine axis

40 longitudinal axis

41 driver's cabin

Claims (7)

1. A traction means tensioning device (1) for a traction means drive (2) having at least the following components:

-at least one tensioning roller (3, 4) for rolling on a traction means (5) of the traction means drive (2); and

-at least one tensioning means (6) for pre-tensioning the tensioning roller (4) against such a traction means (5),

it is characterized in that the preparation method is characterized in that,

the traction means tensioning device (1) further comprises a torsional vibration damper (6) having an input side (7) and an output side (8), and the at least one tensioning roller (4) is damped by means of the torsional vibration damper.

2. Traction means tensioning device (1) according to claim 1, characterized in that the tensioning means (6) is formed by the torsional vibration damper.

3. Traction means tensioning device (1) according to claim 1 or 2, characterized in that the torsional vibration damper is a rocking damper (9).

4. Traction means tensioning device (1) according to any one of the preceding claims, characterized in that the traction means tensioning device (1) has a first tensioning roller (3) and a second tensioning roller (4) which are provided for rolling on a traction means (5) and which can be pretensioned against such a traction means (5) by means of the tensioning means (6),

wherein the first tensioning roller (3) is arranged on an input side (7) of the torsional vibration damper and the second tensioning roller (4) is arranged on an output side (8) of the torsional vibration damper.

5. Traction means drive (2) for a drive train (10), having at least the following components:

-a first traction means disc (11) for connection with a drive shaft (14) of a drive machine (15);

-a second traction means disc (12) for connection with a rotor shaft (16) of an auxiliary unit (17); and

-traction means (5) connecting the first traction means disc (11) and the second traction means disc (12) in a torque-transmitting manner,

wherein the traction means (5) is tensioned by means of a traction means tensioning device (1) according to any one of the preceding claims.

6. Drive train (10) having at least the following components:

-a drive machine (15) having a drive shaft (14);

-an auxiliary group (17) with a rotor shaft (16); and

-a traction means transmission (2) according to claim 5, by means of which the drive machine (15) and the auxiliary aggregate (17) are interconnected in a torque-transmitting manner.

7. A motor vehicle (18) having at least one drive wheel (19, 20) which can be driven by means of a drive train (10) according to claim 6.

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