CN112065923A

CN112065923A - Belt pulley decoupler having a rotational axis for a belt drive of an internal combustion engine

Info

Publication number: CN112065923A
Application number: CN202010455303.8A
Authority: CN
Inventors: M·黑斯勒; A·斯塔弗尔; L·索瑞特; A·鲁施; M·凯斯勒
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-06-11
Filing date: 2020-05-26
Publication date: 2020-12-11
Also published as: DE102019115752A1

Abstract

A pulley decoupler (1) with a rotational axis (2) for a belt drive (3) of an internal combustion engine, comprising a torsional vibration damper (5) having at least the following components: an input side (6); an output side (7); at least one intermediate element (8, 9) between the input side and the output side; at least one energy storage element (10, 11) by means of which the intermediate element is supported in a manner that can be vibrated with respect to the input side and the output side; and at least one rolling body (12, 13), wherein the intermediate element has a drive track (16) corresponding to the rolling body, and the input side or the output side forms a track side (17) and the corresponding other side forms a force-receiving side (18) having a corresponding track (19) complementary to the drive track, wherein the rolling body is guided in a rollable manner for torque transmission between the drive track and the corresponding track. The belt pulley decoupler is characterized in that the force-receiving side is connected in a torque-transmitting manner to the intermediate element by means of an energy storage element.

Description

Belt pulley decoupler having a rotational axis for a belt drive of an internal combustion engine

Technical Field

The invention relates to a belt pulley decoupler having an axis of rotation for a belt drive of an internal combustion engine, a belt drive for a drive train having such a belt pulley decoupler, a drive train having such a belt drive, and a motor vehicle having such a drive train.

The invention relates to a belt pulley decoupler with a rotational axis for a belt drive of an internal combustion engine, wherein the belt pulley decoupler comprises a torsional vibration damper having at least the following components:

-an input side;

-an output side;

-at least one intermediate element between the input side and the output side;

at least one energy storage element, by means of which the at least one intermediate element is supported in a manner that it can oscillate with respect to the input side and the output side; and

at least one rolling body, wherein the intermediate element has a drive track assigned to the rolling body, and the input side or the output side forms a track side, while the respective other side forms a force-receiving side with a counter track complementary to the drive track,

wherein the rolling bodies can be guided in a rollable manner between the transmission track and the counter track for torque transmission. The belt pulley decoupler is primarily characterized in that the force-receiving side is connected in a torque-transmitting manner to the intermediate element by means of an energy storage element.

Background

Various types of torsional vibration dampers are known from the prior art. A torsional vibration damper is known, for example, from EP 2508771 a1, in which the output side is provided with a (double) cam which acts on a rod-shaped intermediate element, wherein the intermediate element is connected to the input-side disk in a tiltable manner. The intermediate element is prestressed against the output-side cam by means of a compression spring and is biased against the compression spring when passing the cam geometry. The compression spring is connected in a pressure-transmitting manner to the input side opposite the intermediate element, so that a torque is introduced from the input side to the output side via the compression spring.

A further variant of a torsional vibration damper is known from FR 3057321 a1, in which a rod-shaped spring body in the form of a (free-form) solid spring is arranged on the output side, wherein the spring body has a ramp-like drive track on the radial outside, which is connected in a torque-transmitting manner to a roller rolling on the drive track. The roller is rotatably supported on the pin. If torsional vibrations occur, a relative movement is caused between the spring body and the respective roller, and the spring body is offset in a rod-like manner from the roller against its spring force in its rotational relative movement relative to the roller due to the ramp-like drive track. Thereby damping the torsional vibration.

Both the rod of EP 2508771 a1 and the spring body of FR 3057323 a1 are technically difficult to handle and/or expensive to manufacture or assemble if low dissipation, i.e. high efficiency, is desired.

For example, WO 2018/215018 a1 discloses a torsional vibration damper, in which two intermediate elements are provided, which are supported on the output side and on the input side by rolling elements. The rolling bodies run on complementary drive tracks, so that the intermediate element is positively guided. The two intermediate elements are prestressed relative to one another by means of the energy storage element, so that the functionally effective stiffness of the energy storage element can be designed independently of the torque transmission. For many applications, it is required on the one hand to reduce the natural frequency of the torque transmission system and at the same time to be able to transmit high torques. From the first requirement, the functionally effective stiffness must be low. From the second requirement, the energy storage element must have a high rigidity. These conflicting requirements can be solved by means of the rolling elements and the drive track. Torque is transmitted between the input side and the output side only by means of the gear tracks and the rolling bodies arranged between them. The stiffness, which is functionally effective, i.e. changes the natural frequency, translates into a small spring travel due to the small gradient and large torsion angle. The cam mechanism results in a (arbitrarily) low functionally effective stiffness. It is therefore advantageous in this system to be able to design the energy storage element independently of the (maximum) transferable torque. However, the illustrated embodiment with a large number of individual rolling bodies and high requirements on the complementary drive track is complicated and expensive to produce and assemble. Therefore, the system is not competitive in all fields.

Disclosure of Invention

Starting from this, 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 emerge from the independent claims, advantageous configurations of which are set forth in the dependent claims. The features of the claims can be combined in any technically meaningful manner, wherein for this purpose also the features from the explanations given below and from the drawings can be considered, which comprise additional embodiments of the invention.

The invention relates to a belt pulley decoupler having an axis of rotation for a belt drive of an internal combustion engine, wherein the belt pulley decoupler comprises a torsional vibration damper having at least the following components:

-an input side for receiving torque;

-an output side for outputting a torque;

at least one intermediate element in the torque-transmitting connection between the input side and the output side;

at least one energy storage element, by means of which the intermediate element is supported in a manner that can be vibrated relative to the input side and relative to the output side; and

-at least one rolling element,

wherein the intermediate element has a drive track assigned to the rolling elements, and

the input side or the output side constitutes the track side, while the respective other side constitutes the force side,

wherein the rail side has a counter rail complementary to the drive rail, and

wherein the rolling bodies can be guided in a rollable manner between the drive track and the counter track for torque transmission.

The belt pulley decoupler is primarily characterized in that the force-receiving side is connected in a torque-transmitting manner to the intermediate element by means of an energy storage element.

In the following, reference is made to the so-called axis of rotation if no other explicit description of the axial, radial or circumferential direction and the corresponding concept is given. Ordinal numbers used in the foregoing and following description are for clarity of distinction only and do not reflect the order or hierarchy of the elements referenced unless explicitly stated to the contrary. An ordinal number greater than one does not necessarily mean that there must be another such element mandatory.

A belt pulley decoupler is proposed which is suitable for use in a belt drive having at least one drive pulley and at least one driven pulley, which are connected to one another by means of a belt in a torque-transmitting manner. Such a belt drive is used, for example, in the case of an internal combustion engine, in which the drive disk is connected indirectly or directly to a burner shaft (verbrennerwell) as a torque source, for example, in the main operating state of the internal combustion engine. The driven disk is connected, for example, to the rotor shaft of an auxiliary device (for example, an air conditioning compressor or a motor generator). The belt pulley decoupler can be used both in the driving pulley and in the driven pulley. For many applications, the pulley decoupler does not allow deviations in its mounting dimensions from the conventional mounting dimensions of the corresponding pulley, but for most applications the use of a suitable vibration decoupling or advantageous change of the resonant frequency is at least not allowed to be greater than for conventional pulley decouplers.

It is now proposed here to use a torsional vibration damper which is constructed as follows.

In one embodiment, the input side forms, for example, the torque input side, the rail side in the main state, for example, in the transmission of a tractive torque, and the output side forms the force side. In an alternative embodiment, the output side forms the torque input side, the track side, for example in the assistance state, for example in the transmission of a thrust torque, and the input side forms the force side.

The torsional vibration damper proposed here has a small number of individual components and only a small number of rolling bodies and complementary drive tracks, which are referred to here as drive tracks on the intermediate element side and (complementary) counter tracks on the track side. The input side is provided here for receiving torque, wherein it is not excluded here that the input side is also provided for outputting torque. For example, the input side forms a torque input in the main state, for example in the case of a so-called drag torque, i.e. in the case of a torque output by the internal combustion engine and/or the electric machine. The output side is accordingly provided for outputting a torque, wherein the output side is preferably also provided for receiving a torque. The output side therefore forms, for example, an input side for a so-called thrust torque in the assistance state when used in a belt drive of a drive train, i.e., in the exemplary embodiment described above, at least one assistance device outputs an input torque to the internal combustion engine.

In order to prevent torsional vibrations from being transmitted directly from the input side to the output side or vice versa, at least one intermediate element, preferably at least two intermediate elements, is provided. At least one intermediate element is arranged in the torque transmission connection between the input side and the output side. The at least one intermediate element can be moved relative to the input side and relative to the output side in such a way that torsional vibration energy is introduced into the intermediate element and thus onto the energy storage element with a predetermined (functionally effective) stiffness. Thus, the natural frequency of the system incorporating the torsional vibration damper, its mass and stiffness functions can be varied, preferably reduced.

The intermediate element is supported relative to the force-receiving side by means of at least one energy storage element (e.g. an arc spring, a leaf spring, a gas pressure accumulator or the like). The force-receiving side is formed by the input side or by the output side in that a preferably one-piece connecting device, for example a contact surface and/or a rivet point, is formed for the at least one energy storage element.

At least one intermediate element is supported on the raceway side by means of at least one rolling body, wherein the intermediate element has a drive raceway for each of the rolling bodies and a complementary counter raceway is formed for the same rolling body on the raceway side. The rail side is formed by the output side or by the input side in such a way that a counter rail, preferably formed in one piece with the rail side, is formed for the at least one rolling element. Torque is transmitted through the corresponding track and the drive track. Torque is also transferred between the force-receiving side and the intermediate element via the energy storage element.

For example, if a torque is introduced from the track side, for example the input side, the rolling bodies roll on the transmission track and the complementary counter track from the rest position in the respective direction (upwards) on the ramp-like transmission track due to the torque gradient that exists as a result of the torsional vibration damper. The upward scrolling is referred to herein as work for illustration only. Rather, the reaction force of the energy storage element is overcome due to the geometrical relationship. Rolling down therefore means that the energy stored by the energy storage element is output in the form of a force acting on the corresponding intermediate element. Therefore, upward and downward do not necessarily correspond to spatial directions, even in a coordinate system that rotates with it.

By means of this torque-dependent movement, the rolling bodies force the respective intermediate element into a relative movement with respect to the rail side and the force-receiving side, and the counteracting energy storage element is correspondingly tensioned. For example, in the case of torsional vibrations, if the applied torque changes and at the same time a rotational speed difference occurs between the track side and the force side, the inertia of the force side (here) opposes the applied torque and the rolling elements roll (in a predefined manner) back and forth on the drive track and on the complementary counter track about a position corresponding to the applied torque. The rolling bodies therefore work against the energy storage element tensioned according to the torque magnitude, so that the natural frequency changes compared to the rest position or the torque transmission without a torsional vibration damper (but with the same flywheel mass).

The force is received by a correspondingly embodied energy storage element in the form of compression, tension, torsion or other energy storage, and is transmitted to the force-receiving side with a time delay, preferably (virtually) without dissipation. Thus, the torque input quantity (in this case) on the rail side, including torsional vibrations, is preferably transmitted (almost) loss-free and time-variable (in this case) to the force-receiving side. Furthermore, as described above, the natural frequency is not constant, but depends on the torque gradient and thus on the applied torque due to the changeable position of the intermediate element.

In the opposite case of the introduction of a torque via the force-receiving side, for example the output side, the at least one energy storage element is loaded in the other direction and thus introduces a corresponding force on the intermediate element. The rolling bodies correspondingly roll on the drive rail in the other direction (opposite to the above-described torque introduced via the rail side) (upward). This movement of the rolling bodies therefore first causes a loading of the energy storage element. When the torque changes, as occurs in torsional oscillations, the at least one energy storage element is displaced around a position corresponding to the applied torque and the stored energy is transferred to the track side in a changing, i.e. time-delayed, movement in common with the rolling bodies rolling between the drive track and the complementary counter track. This changes the natural frequency of the torque transmission system with the torsional vibration damper engaged.

In the opposite configuration, the force-receiving side is formed by the input side, while the rail-board side is formed by the output side. The function is the same as in the above description in which the input side is replaced by the output side and the output side is replaced by the input side.

In one embodiment, two or more intermediate elements are provided, which are preferably arranged rotationally symmetrically with respect to the axis of rotation, so that the torsional vibration damper is balanced by simple means. For a small number of components and (transmission) rails, an embodiment with exactly two intermediate elements is advantageous.

Preferably, two energy storage elements are provided in each case for acting on the (single) intermediate element, wherein the energy storage elements are arranged opposite one another and preferably enter into a state of equilibrium with one another in each case with the embodiment of the drive track and the complementary counter-track. In an alternative embodiment, at least one positive guide is provided, by means of which at least one of the intermediate elements is guided geometrically, for example, forced in the manner of a rail or a groove and a pin or an embedded spring which is gripped. Thus, the movement of the respective intermediate element is (geometrically) over-defined.

In an advantageous embodiment of the belt pulley decoupler, it is further proposed that the at least one intermediate element is supported exclusively by means of the at least one respective energy storage element and the at least one respective rolling element.

In this advantageous embodiment, the at least one intermediate element, when supported by the at least one rolling element and by the at least one energy storage element, has no further support. No (additional) friction effect therefore occurs. In the axial direction, the at least one intermediate element is guided by means of the at least one energy storage element, the at least one rolling element, the contact surface on the force-receiving side and/or the rail side. Preferably, the at least one intermediate element is held in a purely frictional manner in the axial direction by the at least one rolling element and/or the at least one energy storage element and is secured only by an axial stop against loss in the event of an unforeseen loading with an axial force component.

In an advantageous embodiment of the torsional vibration damper, it is furthermore proposed that the at least one intermediate element is connected to the force-receiving side in a torque-transmitting manner by means of two opposing energy storage elements.

In this embodiment, the energy storage element is reliably set in a well-controlled manner by the intermediate element or the pretensioning of the intermediate element against the at least one rolling element. For example, in the case of identical energy storage element configurations, the dependence on component tolerances, for example the spring characteristic of the energy storage elements, is small in that the tolerances decrease with respect to one another, for example, the stiffness deviating downwards from the nominal stiffness of the first energy storage element is compensated or reduced by the stiffness deviating upwards of the second energy storage element. In the case of the same deflection direction, the pretension is reduced or increased overall compared to the nominal pretension, but due to the counteracting effect, for example, compensation is still carried out on both sides of the intermediate element. In one embodiment, only the rest position of the intermediate element is changed. The tolerance is preferably so small that the rest position remains within a predetermined tolerance range. In the embodiment with two intermediate elements, the (four) energy storage elements are connected to one another in such a way that the first (or second) energy storage element of the first intermediate element is also in antagonistic connection (by means of the force-receiving side) with the second (or first) energy storage element of the second intermediate element and a compensation effect is achieved for component tolerances of the energy storage elements. Overall, therefore, the manufacturing accuracy, the assembly or calibration effort and/or the costs of the standard component are reduced due to the lower component quality.

In an advantageous embodiment of the torsional vibration damper, furthermore, provision is made for: the first energy storage element exerts a first force and a first force direction on the intermediate element, and the second energy storage element exerts a second force and a second force direction on the intermediate element,

wherein the first force and the second force are different from each other and/or the first force direction and the second force direction are different from each other in the rest position.

It should be noted that the energy storage element does not tilt about the radial axis, or that such tilting does not contribute to the effect on the natural frequency. The force direction described here is therefore defined as a vector which lies in the following plane of rotation: the axis of rotation is oriented normally with respect to the plane of rotation. It should furthermore be noted that the force directions of the two opposing energy storage elements are always not identical if viewed in a global, i.e. common, coordinate system. In this case, one force direction is referred to a mirror image of the respective other force direction, i.e. a mirror image on the rest axis or center line (in the rest position) of the intermediate element and a mirror image of a possible force-receiving side, which deviates from the respective other force direction.

Here, force merely represents the magnitude of a force vector, wherein the force vector can therefore be decomposed into a force (magnitude) and a force direction (direction of action).

It should furthermore be noted that in the case of a symmetrical design, the forces and the force directions of the two opposing energy storage elements differ from one another in the deflected state of the intermediate element, whereas in the case of an asymmetrical design as proposed here, the same can be true in the deflected state.

In this embodiment, different torque characteristic curves are provided for the traction torque transmission and the oppositely oriented thrust torque transmission, so that the influence of the torsional vibration damper on the natural frequency differs depending on the torque direction. Preferably, the intermediate element is balanced here as described above by means of a corresponding drive track.

In one embodiment, the two antagonistic energy storage elements used (in the uninstalled state, i.e. the uninstalled state) are identical. In this case, the different forces are provided, for example, by means of a deviating shape of the traction torque pair and the thrust torque pair of the drive track relative to each other (see the following description). In a further variant, the different forces are provided by means of mounting distances of different lengths between the force-receiving side and the intermediate element.

The different force directions are achieved, for example, by different inclinations of the contact surfaces on the intermediate element and/or the force-receiving side for the two opposing energy storage elements. In one embodiment, the deflection of the force direction by the intermediate element is variable in that at least one of the two opposing energy storage elements is tilted about an axis parallel to the axis of rotation. Due to the different force directions, in an originally identical energy storage element, the spring path, i.e. the energy reception, is different in the case of a (same) deflection of the intermediate element. Thus, in this installation situation, the stiffness of the same antagonistic energy storage elements is different. The use of the same energy storage element is advantageous in terms of cost and assembly effort or assembly safety. In the present case, however, the same energy storage element is used only for illustrating the situation, and the application of different force directions is not limited to this case.

In an advantageous embodiment of the belt pulley decoupler, it is furthermore proposed that the at least one intermediate element is supported on the track side by means of two rolling bodies.

In this embodiment, the intermediate element is forced to execute a movement pattern due to the double guidance by the two rolling bodies and the two mutually synchronized drive tracks and the respective complementary counter tracks. In this case, such an embodiment can be provided such that the at least one energy storage element only exerts a preload function on the rolling bodies with respect to the stability of the position of the intermediate element, for example, by means of a radial force component of the force acting on the respective intermediate element. Furthermore, even in embodiments without additional (positive) guide elements, the force introduced into the intermediate element does not need to be used to set the moment balance. Only the radial pressing force resultant must be sufficiently large to ensure torque transmission by means of the drive track (i.e. the traction torque pair or the thrust torque pair) when applying torque. In a preferred embodiment, such a moment balance is approximated, so that dissipation effects due to forced relative movements between the at least one energy storage element and the corresponding intermediate element are reduced or even avoided.

In an advantageous embodiment of the belt pulley decoupler, it is furthermore provided that the at least one intermediate element is supported on the track side by means of a single rolling body.

This embodiment is particularly advantageous in terms of a low number of components and thus low part and assembly costs. In one embodiment, at least one positive guide is additionally provided, by means of which at least one of the intermediate elements is guided geometrically, for example, forced in the manner of a track or groove and a pin or an embedded spring which is gripped.

In a preferred embodiment, in a (non-positively guided) embodiment without additional (positively guided) guide elements for positive guidance, it is required that the force direction of the introduction of the force, i.e. the orientation of the force vector along or parallel to the line of action of at least one energy storage element, preferably two energy storage elements, intersects the line of action of the resultant (counter) force generated by the rolling elements, which extends through the rolling center (rolling axis) of the rolling elements and is oriented perpendicularly to the drive track and perpendicularly to the complementary counter track, independently of the offset of the intermediate element in the moment equilibrium point of the intermediate element. Thus, there is a moment balance on the intermediate element around the moment balance point of the intermediate element. The force contribution of the force vector guided by the rolling elements thus corresponds to the force of the at least one energy storage element or to the force contribution acting on the intermediate element. That is, if the force of the energy storage element increases, the resultant force generated by the rolling elements in this structural rule also increases. Thus, the force vectors in the two opposing energy storage elements constitute a force triangle.

In addition, in an advantageous embodiment of the belt pulley decoupler: the drive track and the complementary counter track each comprise a traction torque pair having a first drive curve and a propulsion torque pair having a second drive curve, wherein the traction torque pair is provided for transmitting a torque from the input side to the output side, wherein the propulsion torque pair is provided for transmitting a torque from the output side to the input side,

the first and second transmission curves have at least partially mutually different transmission profiles.

Basically, the tractive torque and the propulsive torque do not differ in the theoretical application. Thus, these terms should be considered neutral and are only used to simply distinguish the noted torque transmitting direction. These terms are taken from the generic names in the drive train of a motor vehicle, but can be transferred to other applications accordingly. In the case of a traction torque transmission, for example, a traction torque pair is applied from the input side to the output side, wherein the rolling bodies on the traction torque pair roll (upward) against the opposing force of the energy storage element with increasing torque. Thus, the potential energy of the antagonistic energy storage element increases, for example is tensioned and thereby changes the stiffness. Thus, the torsional vibration resists the greater force of the opposing energy storage element with increasing torque, and the natural frequency changes accordingly. This applies correspondingly to the thrust torque pair, wherein the rolling bodies are forced to roll (upward) on the thrust torque pair as a result of the loading of the energy storage element.

In this embodiment, the first and second transmission curves, which each start from a common point in the rest position, are provided with different transmission profiles. The stiffness characteristic of the torsional vibration damper can therefore be set (differently) for the drag torque and the push torque in a personalized manner.

In one embodiment, for example, a low stiffness is required for transmitting the drag torque, which can be achieved by a correspondingly larger torsion angle (smaller reduction ratio, i.e. smaller denominator of the transmission ratio) than is desired for the pushing torque (larger reduction ratio). Furthermore, for example, an increasing or decreasing stiffness profile, or even a multiple-change stiffness profile, is desired. For example, a small stiffness increase is provided in the region close to idle, a steep stiffness increase is provided for the main load torque, which is in turn reduced in a gradually decreasing manner, and an increasing stiffness increase is provided again until a maximum transmission value of the transmittable torque is reached.

The transmission path and the complementary counter path are designed in such a way that they correspond to the respective offset position of the intermediate element, so that the transmission curve is superimposed on the movement of the intermediate element. The drive rail and the complementary counter rail are preferably embodied in the manner described above for torque compensation, preferably so that the intermediate element does not require additional (positive) guiding means.

In addition, in an advantageous embodiment of the belt pulley decoupler: the at least one energy storage element is a helical compression spring having a straight spring axis.

A helical compression spring with a straight spring axis, also called a (pure) cylindrical helical compression spring, is a widely used standard component, the elasticity and (low) dissipation characteristics of which are well utilized and can be simply controlled. Simple means can be used to compensate for tolerances in the length of the structure or tolerances in the spring characteristic over a predetermined installation length. Furthermore, such helical compression springs do not require additional guidance, which would otherwise cause friction and thus may have reduced efficiency and/or make it more difficult to obtain damping characteristics due to hysteresis effects. Furthermore, helical compression springs enable a large variation of the spring characteristic curve, which can be set in particular by the helical pitch, the wire thickness, the ratio of the installation length to the relaxation length and the material selection.

Furthermore, the helical compression spring with a straight spring axis is fracture-proof in comparison to springs of other types of construction, for example steel springs, and in some embodiments can be loaded and compacted, so that in the event of an overload on the torsional vibration damper, depending on the design, in such an embodiment in which the energy storage element can be compacted, no additional securing element has to be provided to prevent the energy storage element from fracturing. Furthermore, the helical compression spring has the following advantages: the high spring stiffness and the long spring travel enable a large torque to be transmitted via the at least one energy storage element on the one hand, and on the other hand, a suitable movement reduction ratio can be set by means of the transmission path, so that a reduced movement amplitude of the intermediate element is achieved in relation to the amplitude of the torsional vibrations, and thus torsional vibrations are induced in the very small spring travel of the helical compression spring. As a result, the helical compression spring resists torsional vibrations with a (moderate) small force despite having a high stiffness.

In an advantageous embodiment of the torsional vibration damper, furthermore, provision is made for: at least one energy storage element, which is preferably embodied as a helical compression spring having a straight spring axis, is mounted on the intermediate element and/or on the force-receiving side in a displaceable manner transversely to the spring axis.

Due to this movability, despite the radial movement component of the movement of the intermediate element, which is forced in many embodiments, and/or the non-tangential orientation of the point of action of the spring axis on the intermediate element or on the force-receiving side contact surface, a small counter moment (moment equilibrium point around the intermediate element) is still applied to the free-deflection property of the intermediate element. The movability is provided by means of suitable surface properties with small opposing friction forces or by means of a separate bearing pair. The energy storage element is prevented from tilting and a guide or a small relative movement is provided, so that despite the (small) friction forces the tilting moment is never large enough to deflect the energy storage element accordingly.

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

-a first belt pulley for connection with a drive shaft of a drive machine;

-a second belt pulley for connection with a rotor shaft of an auxiliary device; and

a belt connecting the first belt pulley and the second belt pulley in a torque-transmitting manner,

wherein the first pulley and/or the second pulley comprise a pulley decoupler according to any one of the preceding claims.

The belt drive is provided for transmitting torque from the drive machine to the auxiliary device and vice versa, for example in the case of a motor generator as an auxiliary device. For this purpose, belt discs are provided on at least two connected shafts, namely on at least one drive shaft of at least one drive machine (for example an internal combustion engine) and on at least one rotor shaft of at least one auxiliary device (for example an air conditioning compressor), in each case in a torque-proof connection. A belt is tensioned on the belt pulley such that a torque can be transmitted to the other belt pulley in a friction-locking or form-locking manner into a traction force (traction means, for example a V-belt) or a pushing force (pushing the chain belt). At least one of the belt pulleys, preferably the belt pulley on the drive shaft embodied as a crankshaft, comprises a belt pulley decoupler with a torsional vibration damper according to an embodiment of the preceding description. The torsional vibrations are thus decoupled from the rest of the belt drive, for example the rotor shaft of the auxiliary device, by appropriately shifting the natural frequency range of the belt drive. At the same time, the belt pulley decoupler can be implemented with small installation dimensions, so that it can be integrated into a conventional belt pulley despite meeting the usual transmission ratio requirements (i.e. the diameter ratio of the belt pulley).

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

-a drive machine having a drive shaft;

-an auxiliary device having a rotor shaft; and

a belt drive according to the above-described embodiment, by means of which the drive machine and the auxiliary device are connected to one another in a torque-transmitting manner.

The drive train is provided for transmitting a torque, which is provided by a drive machine, for example an internal combustion engine or an electric machine, and which is output via its output shaft, to at least one consumer. In motor vehicle applications, an exemplary consumer is at least one drive wheel for propelling a motor vehicle, for example a motorcycle, and additionally an auxiliary device, for example a generator for providing electrical energy. In one embodiment, a plurality of drive machines, for example an internal combustion engine and at least one electric machine, for example a motor generator, are provided in a hybrid drive train. Such motor generators form, for example, auxiliary devices and are used both for receiving torque (for generating electrical energy) and for outputting torque (for starting the internal combustion engine). The belt drive enables a torque transmission between the auxiliary device and the drive machine, wherein the natural frequency is suitably shifted in at least one of the belt pulleys by means of the belt pulley decoupler, so that the torque-receiving device, for example the auxiliary device, is protected from resonant oscillations, i.e. vibration decoupling. The belt drive proposed herein has a small installation size and can replace conventional belt drives without other required changes. Furthermore, efficiency is improved relative to systems having other decoupling devices.

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

Nowadays, most motor vehicles have front-wheel drive and the drive machines, such as internal combustion engines and/or electric machines, are arranged partly in front of the driver's cabin and transversely to the main driving direction. The radial installation space is just particularly small in this arrangement, and therefore the use of a drive train with components of small installation dimensions is particularly advantageous. The drive train in a motor-driven two-wheeled vehicle is similarly configured, which requires an increased output over known two-wheeled vehicles at all times while maintaining an equal installation space. With the hybridization of the drive train, this problem is also exacerbated for rear axle arrangements and here also in the longitudinal arrangement as well as in the transverse arrangement of the drive assembly.

In the motor vehicle proposed here with the drive train described above, a high efficiency is achieved due to a high running stability and thus a very constant belt tensioning by integrating a very efficient torsional vibration damper in at least one of the belt pulleys of the belt drive of the drive train. At the same time, the required installation space is at least not larger than that conventionally used, and the costs are not increased compared to conventional vibration decoupling systems.

Passenger cars correspond to vehicle classes according to, for example, size, price, weight and power, wherein this definition is subject to constant changes according to market demand. In the us market, the vehicle classes of small vehicles and miniature vehicles correspond to the super-small vehicle classes according to the classification in europe, and in the uk market such vehicles of small vehicle and miniature vehicle classes correspond to the super-mini class or the city vehicle class. An example of a mini car class is the popular up! Or Reynolds Twingo. Examples of minicar classes are alpha RomeO MiTo, Volkswagen Polo, Ford Ka +, or Reynolds Clio. The known full hybrid vehicles in the small vehicle class are BMWi3 or yota Yaris hybrid.

Drawings

The above invention is explained in detail in the related art background with reference to the drawings showing preferred configurations. The invention is not limited to the purely schematic representations, in which it should be noted that the figures are not to scale in nature, nor are they suitable for defining dimensional relationships. It shows

FIG. 1: a schematic diagram of a first embodiment of a torsional vibration damper;

FIG. 2: a schematic diagram of a second embodiment of a torsional vibration damper;

FIG. 3: a schematic representation of the forces exerted on the intermediate element;

FIG. 4: force triangle of force applied according to fig. 3;

FIG. 5: a schematic diagram of a third embodiment of a torsional vibration damper;

FIG. 6: a schematic diagram of a fourth embodiment of a torsional vibration damper;

FIG. 7: a torque-torsion angle diagram having a first transmission curve;

FIG. 8: a torque-twist angle map having a second drive curve;

FIG. 9: a torque-twist angle diagram having a third drive curve;

FIG. 10: a torque-twist angle diagram having a fourth and a fifth transmission curve;

FIG. 11: a schematic cross-sectional view of a pulley decoupler with a torsional vibration damper; and

FIG. 12: a motor vehicle having a drive train including a pulley decoupler.

Detailed Description

Fig. 1, 2, 5 and 6 each show, in a schematic illustration, an exemplary embodiment of a torsional vibration damper 5, which is shown as identically as possible for clarity and to which reference is made in cross-section to the description of identical components in the respective figures. The annular disk forms the output side 7, which in fig. 1 and 5 forms the rail side 17 and in fig. 2 and 6 forms the force-receiving side 18. In the center of the common axis of rotation 2, the other disk element is, for example, designed as an input side 6, which in fig. 1 and 5 forms a force-receiving side 18 and in fig. 2 and 6 forms a track side 17. Alternatively, the annular disc is the input side 6 and the disc elements are the output side 7. In the following, the aforementioned variants are explained, wherein these terms are interchangeable.

As illustrated by the arrows, the drag torque 43 can be transmitted from the input side 6 to the output side 7, while the push torque 44 can be transmitted from the output side 7 to the input side 6. In one embodiment, the torque direction is reversed.

Two

intermediate elements

8, 9 are arranged in an intermediate connection between the input side 6 and the output side 7, wherein, toward the force-receiving side 18, the respective

intermediate element

8, 9 is connected in a force-transmitting and thus torque-transmitting manner to the first energy storage element 10 and the second energy storage element 11 arranged in pairs, and is supported on the raceway side 17 in a force-transmitting and thus torque-transmitting manner to the complementary counter-raceway 19 by means of the power transmission raceway 16 and the first and second rolling

bodies

11, 12 rolling thereon. The rolling

bodies

12, 13 are prestressed against the drive track 16 and against the counter track 19 by means of the

energy storage elements

10, 11 and are thus guided in a rollable manner thereon. In the position shown, the

energy storage elements

10, 11 hold the

intermediate elements

8, 9 in the rest position in an antagonistic manner. In the second rolling element 13 shown in the illustration, the traction torque pair 28 is formed by complementary ramp portions of the drive rail 16 and of the counter rail 19, respectively, and the thrust torque pair 28 on the respective other side is formed by complementary ramp portions of the drive rail 16 and of the counter rail 19, respectively, next to the rest position in which the second rolling element 13 is shown. The operation of these tracks is explained in detail below. In the embodiment shown, the

intermediate elements

8, 9 are supported exclusively by the

energy storage elements

10, 11 and the respective rolling

elements

12, 13.

In contrast to fig. 1, fig. 2 shows an embodiment in which the track side 17 and the force-receiving side 18 are reversed, so that the input side 6 forms the track side 17 and the output side 7 forms the force-receiving side 18.

Fig. 3 shows a schematic illustration of the moment balance and fig. 4 shows a force triangle formed by the first intermediate element 8 or the second intermediate element 9 and the first rolling element 12 or the second rolling element 13 according to the embodiment of fig. 1. The

intermediate elements

8, 9 are guided out of their rest position and are deflected at a deflection angle relative to the rest position with their center lines 45 obliquely to the rest lines 46. A rest line 46, which coincides with the center line 45 in the rest position, always extends through the axis of rotation 2 like the center line 45, but only passes through the moment equilibrium point 47 of the

intermediate elements

8, 9 in the rest position. The center line 45, which always passes through the moment compensation point 47 and the axis of rotation 2, is not to be understood as a geometric center or a center related to mass of the

intermediate elements

8, 9, but rather as a center related to force. If it is required that the

intermediate elements

8, 9 do not require additional guidance, a moment equilibrium must be present at the moment equilibrium point 47 of the

intermediate elements

8, 9. The stationary line 46 must always be oriented perpendicularly to the (theoretically infinite) abutting section of the drive rail 16. A stationary line 46 extends through the moment compensation point 47 and the rolling axis of the rolling

elements

12, 13. In order to maintain this rule in constant compliance, a second parallel line of equally or proportionally spaced apart parallel lines of the first line of action 48 of the first force 20 proceeding from the first energy storage element 10 and the second line of action 49 of the second force 22 proceeding from the second energy storage element 11 intersects the center line 45 and the stationary line 46 at the moment equilibrium point 47, so that no (effective) lever arm is produced. In addition, the first force 20, the second force 22, and the resultant force 24 are required to form a self-canceling force triangle as shown in FIG. 4. For this purpose, the first force direction 21, the second force direction 23 and the resulting force direction 25 must be present as shown. As can be seen from the illustrated position, both the first energy storage element 10 (see fig. 1) and the second energy storage element 11 (see fig. 1) are tensioned more strongly, as a result of which an increased prestress acts on the

intermediate elements

8, 9. In this embodiment, the stronger tensioning results from the

intermediate elements

8, 9 moving radially inwards, so that the

energy storage elements

10, 11 are compressed with the radially inwards movement and in the manner of a screw clamp between the adjoining

intermediate elements

8, 9. The

intermediate elements

8, 9 are therefore moved such that the spacing between the respective

intermediate elements

8, 9 along the spring axes 30, 31 of the

energy storage elements

10, 11 is shortened relative to the rest position if increased stiffness is desired at higher torques (see fig. 5 to 8). Therefore, in order to correctly orient the pressure line 50, i.e. the line of action of the resultant force 24, the pressure line 50 intersecting the rolling axis of the rolling

bodies

12, 13 and the moment equilibrium point 47 is always perpendicular to the second transmission curve 29 of the transmission path 16, here corresponding to the thrust moment 44. The magnitude of the resultant force 24 and the resultant force direction 25 are inherently derived from the applied first and

second forces

20, 22.

Fig. 5 and 6 show variants with respect to the embodiments in fig. 1 and 2, respectively, in which a positive guidance is present here on the

intermediate elements

8, 9, in that, in addition to the first rolling element 12 or the second rolling element 13, a further rolling element, namely a third or fourth rolling

element

14, 15, is provided. In this embodiment, deviations are made from the embodiment in which a moment balance and a force balance are required on the respective

intermediate element

8, 9. It is only necessary that a sufficient force (vector) component is generated by the (first) energy storage element 10 (and here also the second energy storage element 11) in order to hold the rolling

bodies

12, 13, 14, 15 between the respective drive track 16 and the complementary counter track 19 or to press the respective

intermediate element

8, 9 against the two rolling

bodies

12, 13, 14, 15. In principle, more

rolling elements

12, 13, 14, 15 can also be used. Fig. 5 refers to the description of fig. 1 and fig. 6 refers to the description of fig. 2.

Fig. 7 to 10 show a torque-torsion angle diagram, wherein the torque axis 51 forms the ordinate and the torsion angle axis 52 forms the abscissa. In this embodiment, a traction torque curve with a positive torque and a torsion angle is shown on the right side of the ordinate, and a pushing torque curve with a negative torque and a torsion angle is shown on the left side of the ordinate.

In fig. 7, a first transmission curve 27 corresponding to the drag torque pair 26 and a second transmission curve 29 corresponding to the push torque pair 28 are shown in two-step progression, so that a flat curve progression exists when the torque magnitude is small and a steep curve progression exists when the torque magnitude is large.

Fig. 8 accordingly shows a two-step reduction variant, in which a steep curve rise is present when the torque magnitude is small, and a flat curve rise is present when the torque magnitude is large.

Fig. 9 shows a variant in which the increasing and decreasing curves alternate, and in fig. 10 a comparison is shown of a rigid system with a steep curve trend shown in solid lines compared to a system with a flat curve trend shown in dashed lines.

For the embodiment of fig. 1 and 2 without additional guidance of the

intermediate elements

8, 9, such transmission curves 27, 29 comply with the conditions of moment and force balance as illustrated in fig. 3 and 4. The illustrated drive curves 27, 29 are therefore implemented in superposition with the requirements for the drive rail 16 according to the description of fig. 1 (and 2). Furthermore, in one embodiment, in the rest position, the force 20 or the stiffness of the first energy storage element 10 differs from the second energy storage element 11 and is not implemented symmetrically as illustrated in fig. 1 and 2. This is also noted for the superposition to achieve the desired transmission curves 27, 29.

With the torsional vibration damper 5 proposed here, a cost-effective and effective influencing of the natural frequency can be achieved with a small number of components.

Fig. 11 shows a belt pulley decoupler 1 with a torsional vibration damper 5, for example, according to fig. 2 or 6, in a simplified section at, for example, the first intermediate element 8 (with continued reference to fig. 1 and the corresponding description). The input side 6 is formed here (optionally) in one piece with a shaft connection 53, which is shown here (optionally) connected to the drive shaft 34, for example a crankshaft, by means of a shaft connection 54. The output side 7 is formed here (optionally) in one piece with a belt pulley 33, 36, which forms a corresponding belt receptacle for a belt 39, which is here (optionally) embodied as a V-belt, radially on the outside. The drag torque 43, which is illustrated here as the output torque of the drive shaft 34, about the common axis of rotation 2, is conducted from the shaft connection 53 into the belt pulleys 33, 36 only by means of the torsional vibration damper 5.

The drag torque 43 is thus transmitted from the input side 6 to the first rolling elements 12, so that they roll on the input side 6, in this case on the first counter track 19 arranged radially outside the input side 6. This rolling movement is in turn transmitted to the intermediate element 8, here to a (complementary) first transmission track 16 arranged radially inside the intermediate element 8. The stepped embodiment of the first rolling elements 12 (and possibly of the second rolling elements 13) is optional, but is advantageous for sufficient axial fixing of the respective rolling

elements

12, 13. The drag torque 45 is transmitted from the intermediate element 8 to the output side 7 by means of the first energy storage element 10 (or the second energy storage element 11, which is not shown here). For a better understanding of fig. 11 only, it should be pointed out that the (rectangular in the illustration) sections of the

respective parts

8, 53, 33, 36 are shown radially opposite the

tracks

16, 19 of the rolling

elements

12, 13, respectively. When the pushing torque 44 is transmitted from the belt 39 to the drive shaft 34, the rolling

bodies

12, 13 are forced to move in opposite directions by means of the

tracks

16, 19. However, the rolling of the rolling

bodies

12, 13 on the

tracks

16, 19 is suppressed by the

forces

20, 22 of the energy storage element 10 (here the first energy storage element 10: the second energy storage element 11 in active engagement is not shown). The

energy storage elements

10, 11 are (optionally) embodied here as helical compression springs. Thus, although a large torque forces only a relatively small torsion angle between the input side 6 and the output side 7 due to the high (spring) stiffness of the

energy storage elements

10, 11, the oscillating movement of the rolling

bodies

12, 13 is only opposed by the deceleration rolling gear formed by the

tracks

16, 19 to a small (spring) stiffness. Thus, a large torque can be transmitted by using

energy storage elements

10, 11 with a high (spring) stiffness. At the same time, a desired reduction of the (system) resonance frequency can be achieved due to the flexibility (low stiffness) of the movement of the rolling

elements

12, 13.

Fig. 12 schematically shows a motor vehicle 40 in a top view. The motor vehicle 42 has a left drive wheel 41 and a right drive wheel 42, which are provided for propelling the motor vehicle 40 in the main direction of travel (to the left according to the illustration along the longitudinal axis 55). The torque required for this purpose is made available on demand by a drive machine 35, here (optionally) the internal combustion engine 4, by means of a drive shaft 34 of the drive train 32 shown. Furthermore, power is to be supplied to consumers, for example, a battery or an air conditioning compressor, by means of the drive machine 35. For this purpose, a belt drive 3 is provided, which connects the drive shaft 34 to a rotor shaft 37 of an auxiliary device 38 (e.g., a motor generator) in a torque-transmitting manner. The belt drive 3 comprises a first belt pulley 33 on the drive shaft 34 and a second belt pulley 36 on the rotor shaft 37, which are connected to one another by means of a belt 39 in a torque-transmitting manner. Here, (optionally) only the first pulley 33 comprises the pulley decoupler 1.

With the belt pulley decoupler proposed herein, the rotational speed fluctuations of the disturbances and the movement and noise of the belt can be reduced and the service life of the belt drive assembly can be extended.

List of reference numerals

1 Belt pulley decoupler

2 axis of rotation

3 Belt transmission mechanism

4 internal combustion engine

5 torsional vibration damper

6 input side

7 output side

8 first intermediate element

9 second intermediate element

10 first energy storage element

11 second energy storage element

12 first rolling element

13 second rolling element

14 third rolling element

15 fourth rolling element

16 transmission rail

17 track side

18 force-bearing side

19 corresponding track

20 first force

21 first force direction

22 second force

23 second direction of force

24 resultant force

Direction of resultant 25 forces

26 drag torque pair

27 first transmission curve

28 thrust moment pair

29 second transmission curve

30 first spring axis

31 second spring axis

32 drive train

33 first belt pulley

34 drive shaft

35 drive machine

36 second belt reel

37 rotor shaft

38 auxiliary device

39 leather belt

40 motor vehicle

41 left driving wheel

42 right driving wheel

43 drag torque

44 push torque

45 center line

46 static line

47 moment balance point

48 first line of action

49 second line of action

50 pressure line

51 moment axis

52 torsional angle axis

53 shaft connecting part

54-shaft fastening part

55 longitudinal axis.

Claims

1. Belt pulley decoupler (1) with a rotational axis (2) for a belt drive (3) of an internal combustion engine (4), wherein the belt pulley decoupler (1) comprises a torsional vibration damper (5) with at least the following components:

-an input side (6) for receiving torque;

-an output side (7) for outputting a torque;

-at least one intermediate element (8, 9) in a torque transmitting connection between the input side (6) and the output side (7);

-at least one energy storage element (10, 11) by means of which the intermediate element (8, 9) is supported in a vibratable manner with respect to the input side (6) and with respect to the output side (7); and

at least one rolling element (12, 13, 14, 15),

wherein the intermediate element (8, 9) has a drive track (16) associated with the rolling bodies (12, 13, 14, 15), and

the input side (6) or the output side (7) forming a track side (17) and the respective other side (7, 6) forming a force-receiving side (18),

wherein the rail side (17) has a counter rail (19) complementary to the drive rail (16), and

wherein the rolling bodies (12, 13, 14, 15) are guided in a rollable manner between the drive track (16) and the counter track (19) for torque transmission,

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

the force-receiving side (18) is connected in a torque-transmitting manner to the intermediate element (8, 9) by means of the energy storage element (10, 11).

2. The pulley decoupler (1) according to claim 1, characterized in that the at least one intermediate element (8, 9) is supported solely by means of the at least one corresponding energy storage element (10, 11) and the corresponding at least one rolling body (12, 13, 14, 15).

3. Belt pulley decoupler (1) according to claim 1 or 2, wherein the at least one intermediate element (8, 9) is connected in a torque-transmitting manner with the force-receiving side (18) by means of two opposing energy storage elements (10, 11),

wherein preferably a first energy storage element (10) exerts a first force (20) and a first force direction (21) on the intermediate element (8, 9) and a second energy storage element (11) exerts a second force (22) and a second force direction (23) on the intermediate element (8, 9),

wherein the first force (20) and the second force (22) differ from each other and/or the first force direction (21) and the second force direction (23) differ from each other in a rest position.

4. Belt pulley decoupler (1) according to any of the preceding claims, wherein the at least one intermediate element (8, 9) is supported on the track side (17) by means of two rolling bodies (12, 13, 14, 15).

5. Belt pulley decoupler (1) according to any of the preceding claims, wherein the at least one intermediate element (8, 9) is supported on the track side (17) by means of a single rolling body (12, 13).

6. Belt pulley decoupler (1) according to any of the preceding claims, wherein the transmission track (16) and the complementary corresponding track (19) comprise a traction torque pair (26) with a first transmission curve (27) and a thrust torque pair (28) with a second transmission curve (29), wherein the traction torque pair (26) is arranged for transmitting torque from the input side (6) to the output side (7), wherein the thrust torque pair (28) is arranged for transmitting torque from the output side (7) to the input side (6),

wherein the first transmission curve (27) and the second transmission curve (29) have at least partially different transmission profiles relative to one another.

7. Belt pulley decoupler (1) according to any of the preceding claims, wherein the at least one energy storage element (10, 11) is a helical compression spring with a straight spring axis (30, 31),

wherein the at least one energy storage element (10, 11) is preferably mounted on the intermediate element (8, 9) and/or the force-receiving side (18) so as to be displaceable transversely to the spring axis (30, 31).

8. A belt drive (3) for a drive train (32), having at least the following components:

-a first belt pulley (33) for connection with a drive shaft (34) of a drive machine (35);

-a second belt pulley (36) for connection with a rotor shaft (37) of an auxiliary device (38); and

a belt (39) connecting the first belt pulley (33) and the second belt pulley (36) in a torque-transmitting manner,

wherein the first pulley (33) and/or the second pulley (36) comprise a pulley decoupler (1) according to any one of the preceding claims.

9. Drive train (32) having at least the following components:

-a drive machine (35) having a drive shaft (34);

-an auxiliary device (38) having a rotor shaft (37); and

-a belt drive (3) according to claim 8, by means of which the drive machine (35) and the auxiliary device (38) are connected to each other in a torque-transmitting manner.

10. A motor vehicle (40) having at least one drive wheel (41, 42) which is driven by means of a drive train (32) according to claim 9.