DE19748665A1 - Vibration isolation device and method for operating the same - Google Patents

Abstract

The invention relates to an anti-vibration device, e.g. for the drive train of a motor vehicle, whereby an electric motor (4) is arranged in front of an anti-vibration device (6) in said drive train. The electric motor (4) is used to apply torque to the input shaft (2) or the output shaft (10) in such a way that the anti-vibration device has an enhanced or reduced elastic rigidity with respect to the torque induced by the other shaft (10 or 2).

Description

The invention relates to a device for vibration insulation, e.g. B. in the drive train of a motor vehicle, according to the preamble of claim 1 and a method for operating such a device.

Due to the discontinuous mode of operation, join Internal combustion engines a variety of different Vibration phenomena. Make it particularly noticeable which are caused by torque fluctuations in the combustion engine torsional vibrations in the drive train of a Motor vehicle. These plant themselves over the remaining driving components and lead to one for the vehicle annoying noise and vibration levels. For Avoiding or reducing vibration propagation Vibration isolation is therefore incorporated in the drive train directions used which are associated with the combustion motor-connected drive side and the z. B. to the transmission Coupling the leading output side in a torsionally flexible manner. Such Vibration isolation device leads to an effective "Isolation" of the output side from excitation moments the drive side (and vice versa) if the resonance frequency of the vibration isolation device is smaller than that Excitation frequency, in particular less than 0.7 times the excitation frequency. Because you have a low response frequency and a. achieved through low spring stiffness this operating area also includes the area "softer from Mood".  

According to the prior art, such a Schwin insulation device constructive in the conventional Flywheel of a motor vehicle be integrated. If there with two flywheels via one or more elastic Coupling elements are interconnected, one speaks of a dual mass flywheel (DMF).

An example of a device of the type mentioned Art discloses German patent application 196 31 384.8 the applicant. There is the vibration isolation device tung, z. B. in the form of such a two-mass flywheel, integrated in the rotor of an electric starter machine, with the rotor right on the crankshaft of the cremation motor sits. This arrangement is used for shielding the output side against torque fluctuations on the Drive side (and vice versa). This arrangement is fulfilled satisfactory with the tasks assigned to her. At it is the coordination of the vibration isolation device however faced with conflicting requirements. Egg On the other hand, one chooses to achieve the deepest possible Natural frequency - d. H. the most effective damping - the softest possible coordination of the vibration iso device (i.e. low spring stiffness). There but there is a risk that with large pathogens amplitudes, e.g. B. with a load change, the elastic Coupling elements of the vibration isolation device up to their attack against each other, so that then there is no longer any vibration isolation property. Around even in the case of such large pathogen amplitudes to remain effective insulation, d. H. not in one type vibration isolation would be different on the one hand a hard tuning (high spring stiffness) worth it. The known arrangement can counter this not meet requirements. The required Compromise usually means that the natural frequency the arrangement is chosen relatively high and extremely high pathogen amplitudes a torsion of the Schwin insulation isolator until it stops closed is.

The aim of the invention is a device for Schwin Provide insulation insulation, which is in this Hin behaves more favorably and thus a broader Be drive area. This includes specifying an equivalent appropriate procedure.

The invention achieves this goal through the objects of claims 1 and 10. Advantages of executing the Er invention are in the respective dependent claims wrote.

Then a device for vibration isolation, e.g. B. for a motor vehicle, provided comprises: at least one with a primary drive, e.g. B. an internal combustion engine of the motor vehicle, coupled Powertrain with an input shaft and an output wave; a turn the input shaft and the output shaft elastically coupling vibration isolation device; a electric machine whose rotor with the input shaft and the output shaft rotatably connected or connected and the stator against rotation can be fixed or fixed sets is; and a control device which the elek tric machine controls so that they ver changing torques on the input shaft or the off gangswelle brings up that of the other Wel le (output shaft or input shaft) induced torsion the vibration isolation device reduced or ver is enlarged.

With the help of this arrangement it is possible to find the effective one Spring stiffness of the vibration isolation device to be influence. The arrangement has the advantage that it goes visually the insulation or damping properties of the Vibration isolation device different Schwin situation is adaptable. The elasti rule coupling elements of the vibration isolation device egg ne fixed - material, geometry and dimension dependent - Spring characteristic (so-called specific spring characteristic). Without Control of the electrical machine in the invention  Wise, the aforementioned vibration isolation device to an excitation torque of the input or output shaft with one of the specific spring characteristics of the elasti coupling elements dependent elastic deformation this coupling elements and thus a corresponding gate sion of the vibration isolation device react. At periodically changing excitation moments are eliminated speaking periodically changing torsions of the pig insulation device. The electrical machine supports preferably with their stator against a fixed loading pull point from, e.g. B. a motor or a transmission housing. By operating the electrical machine in such a way that this is also in phase with the excitation moment Torque on the opposite side of the exciter Side of the vibration isolating device the excitation torque is a positive or negative torque superimposed so that the torsion of the vibration isolation direction - depending on the sign of the additional torque - ver is enlarged or reduced. The result is similar to egg a softer or harder vibration isolator direction. The effective spring characteristic appears the vibration isolation device as "variable".

The additional torques caused by the electrical machine on the side of the Vibration isolation device are applied basically according to amount and / or direction (available power range of the electrical machine) any changeable. For example, the electrical machine be controlled so that the time you spend Varying torques proportional to the exciter moments on the excitation side of the vibration isolation direction, d. H. that of the elastic vibration iso torque applied. The To Set torques then differ only by one constant factor and possibly by the sign. As a result the shape of the effective spring characteristic remains unchanged, only the slope of the characteristic curve becomes steeper or flatter.  

The term "taxes" used here is in the sense of the Er to understand the invention broadly and includes in particular Control and regulation processes.

Preferably, however, the additionally differ reduced torques from the excitation torques by one non-constant factor, e.g. B. one with increasing torsion increasing number, so the effective spring characteristic (Spring stiffness) of the vibration isolation device additionally changed in shape, e.g. B. flatter (softer) made, in particular linearized, or on the contrary, at large excitation moments made steeper (harder).

In a particularly preferred variant of the additional torques applied to the electrical machine same sign as the excitation moments and take along increasing torsion of the vibration isolation device Art that the torsion does not meet a predetermined limit exceeds. Such a limit takes into account for example, the state of the elastic coupling elements Vibration isolation device, such as reaching one permissible load or strain, in particular a Striking the coupling elements. To consider at the Control are the properties of the elastic Coupling elements, e.g. B. spring constant, spring length, maximum Elongation, maximum compression, etc. is preferred for this for a specific vibration isolation device a maximum permissible value (limit value) for the torsion determined in which the vibration isolation device straight is still functional as such, as well as an initiation approximate value for the torsion (or a characteristic tical sizes), the amount of which is smaller than the pre called limit. When the initiation is exceeded value is a control signal to apply such Torque that changes over time produces that the Torsion of the vibration isolation device asymptotically the approaches the predetermined limit. The effective spring characteristic line then has a comparatively "smooth" course on.  

A preferred arrangement for vibration isolation in egg nem motor vehicle provides that the electrical machine in the drive train between the internal combustion engine and the transmission is arranged in front of the vibration isolation device, for. B. the rotor of the electrical machine on the drive side with the Crankshaft is rotatably connected and the vibration insulation device between the electrical machine and a shaft leading to the gearbox. You choose in in this case a soft vote, d. H. a relatively ge rings spring stiffness (flat characteristic) of the elastic coupling elements, so a large amplitude leads Excitation torque on the output side, as z. B. at one Load changes occur to the hitting the Schwin insulation device. Now with the electrical Ma additional torque also appears on the drive side Phase with and with the same sign as the excitation moment applied on the output side, so that is from the Vibration isolation device to be transmitted overall and Relative torque reduced. As a result, the torsion the vibration isolation is also reduced, in particular the other by an amount such that strikes prevent is changed. As a result, the insulating property remains Vibration isolation device even with soft tuning preserved even for high excitation moments.

The additional applied by the electrical machine Chen torques depend on the Schwin Insulation device applied load. As Tax quantity for the characterization of the adjacent Bela The torsion of the swine is preferably used insulation device or a character that torsion risky size, e.g. B. the torque of the input shaft and / or the output shaft or the difference between them the torques. To capture these control variables includes the control device preferably one of the Schwin gation isolation device associated rotary encoder for Measuring the torsion of the vibration isolator or one of the input shaft and / or the output shaft  ordered torque sensor. With the help of a suitable ver Work facility are then from the measured tax increase the need to control the electrical machine maneuverable variables derived.

The vibration isolator used in the invention device can basically be any one skilled in the art be of a familiar nature. In a preferred variant comprises the vibration isolation device at least two reason elements, one of which is a basic element on the drive side and the other basic element is arranged on the output side, and the two basic elements via one or more elasti cal coupling elements, in particular screw, spiral or Rubber springs, torsionally elastic are coupled.

As mentioned above, the dynamic is Schwin insulation especially effective in the area of soft ab mood, d. H. at low resonance frequency of the Schwin system. Such a vote will preferably be there achieved by that on one or each of the basic elements Inertia are provided. In the case of two swing This vibration isolation device then corresponds in mass the two-mass flywheel mentioned in the introduction. The Inertia can also be torsionally flexible, e.g. B. via Elasto layers, coupled with the respective basic element be.

With a particularly compact and therefore preferred construction as the arrangement of the invention is the Schwin insulation device in the rotor of the electrical machine arranged integrated. For this, the rotor is the electri rule machine, for example, in the form of a hollow cylinder det. The cavity in the rotor then serves to accommodate the Vibration isolation.

The electrical machine of the arrangement according to the invention for vibration isolation can - in addition to the previously described functions - also take on other functions, for. B. the one

• - Starters to start, especially direct starts, ei internal combustion engine;
• - Generators to supply electrical consumers and / or at least one vehicle battery;
• - regenerative vehicle brake;
• - Drive a vehicle, especially as a drive for support next to the internal combustion engine; and or
• - damper for torque fluctuations of that shaft, with which the rotor of the electrical machine ver is bound. The torque intervention of the electrical machine on the side of the vibration Isolation device instead of the torque fluctuation occurs.

Further advantages and refinements of the invention result preferred from the following description leadership examples. In the description, the beige added schematic drawing referenced. In the drawing show:

Figure 1 is a schematic representation of an exemplary device according to the invention for vibration isolation in the drive train of a motor vehicle.

Fig. 2 is a schematic torque-time diagram of an output-side excitation torque of the arrangement of Figure 1 with and without action of the device according to the invention. and

FIGS. 3 and 4 are each a schematic torque-rotational angle diagram illustrating how the effective characteristic curve of the Schwingungsiso liereinrichtung can be influenced with the inventive device.

Fig. 1 shows schematically an example of an inventive device for vibration isolation, as it can be used in a motor vehicle.

The torque transmission path of the drive train shown runs over a - driven by an internal combustion engine, not shown - crankshaft 2 to an electrical machine 4 , from there through a vibration isolating device 6 through to a clutch 8 and via its clutch disc 9 on a Ge input shaft 10 , which possibly leads via further elements to a (not shown here) transmission of the motor vehicle.

The electrical machine 4 has a z. B. on the motor housing or on the vehicle body rotatably support the stator 12 and a rotatable with the crank shaft 2 on a hub 13 screwed rotor 14 . The rotor 14 has approximately the shape of a hollow cylinder with a U-shaped cross section. The electrically or magnetically active part of the rotor 14 is located on the outside of the side of the hollow cylinder facing the stator 12 . If one chooses a three-phase asynchronous machine as an electric machine 4 (although a machine of the direct current, alternating current, three-phase synchronous or linear type would also be possible), the outer part 16 of the rotor 14 forms a short-circuit squirrel-cage rotor with K axially extending figstäben.

In the cavity of the U-shaped rotor 14 , the vibration isolating device 6 is accommodated. This includes a - shown in Fig. 1 schematically as a spring - elastic coupling element 18 (consisting of several spiral or rubber mifedern), which is connected on the drive side to the rotor 14 and from the drive side with a clutch input part 20 of the coupling 8 . The rotor 14 and the clutch input part 20 - consequently primary and secondary side of the vibration isolation device 6 - are thus coupled to one another via the elastic coupling element 18 in a torsionally elastic manner. In this way, the drive side of the drive train is shielded from torque fluctuations on the output side (and vice versa), and the more effectively the coordination is selected, the more effectively, as already discussed above.

The input part 20 of the clutch 8 (at the same time secondary side of the vibration isolation device 6 ) is freely rotatable about the same axis as the rotor 14 , for. B. in a on the inner leg of the U-shaped Ro tor 14 seated ball bearing 21 , as it is indicated in Fig. 1 cal matically. The drive train shafts 2 and 10 in front of and behind the electrical machine 4 are guided in bearings.

Furthermore, a control device 24 for controlling the electrical machine 4 is provided. This Steuerein direction 24 also includes a pulse inverter 26 for generating rotating fields with current freely adjustable frequency, phase and / or amplitude, with which the stator 12 of the electrical machine 4 is fed to generate a rotating field to apply a torque to the rotor 14 - and thus on the crankshaft 2 - to exercise. To monitor the current torsion, ie the intrinsic rotation of the vibration isolation device 6 , a Drehwinkelge over 30 z. B. net in the vicinity of the clutch input part 20 to continuously measure its instantaneous angle of rotation. By comparing it with the current angle of rotation of the rotor 14 of the electrical machine 4 (which is measured by a similar angle encoder or determined from the currents back-induced in the stator 12 ), the relative angle of rotation ϕ between the primary and secondary sides of the vibration insulation 6 can be determined. But is conceivable in the vibration isolation device 6 inte grated rotary encoder with a transmitting part z. B. on the clutch input part 20 and an opposite receiving part on the inside of the rotor.

According to the invention, the electrical machine 4 is controlled in order to specifically influence the insulation behavior of the vibration isolation device 6 . The electric machine 4 transmits in phase with any pathogen moments of Ab drive side in addition, such torques with the same or opposite sign to the drive-side crankshaft 2 that the drive side of the exciting moments of Ab-induced torsion of the vibration isolating device 6 depending on the sign of the additional torques reduces or enlarges becomes. If one then looks at the relationship between excitation torques and the resulting torsion, the vibration isolation device 6 has a spring stiffness which is different from the specific characteristic of the elastic coupling element 18 . This can be specifically tuned under the influence of the additional torques applied by the electrical machine 4 , as the following examples show.

Fig. 2 shows an exemplary time course of egg nes interference or excitation torque 30 , as it occurs on the drive side of the arrangement from FIG. 1, ie on the gearbox input shaft 10 or on the clutch input part 20 (with clutch 8 open), For example, when there is a load change in the internal combustion engine or an abrupt torque boost from the drive wheels. In this case, the He torque 30 is a substantially uniform From torque 32 superimposed. The drive-side excitation element 30 is "caught" by the vibration isolation device 6 . However, if the amplitude of the excitation torque 30 reaches a maximum value M _max , which is a function of the spring constants of the elastic coupling element 18 , the elastic coupling element 18 of the vibration isolating device 6 is deformed until it stops, so that there is no longer any insulating property.

In order to avoid such an attack, the electrical machine 4 is controlled according to the invention so that it also applies a time-varying torque to the crankshaft 2 in phase with the excitation element 30 , which torque is proportional to the excitation torque 30 on the output side, z. B. differs by a factor k = 0.5, and has the same sign. As a result, the relative torque transmitted between the input side and output side of the vibration isolation device 6 is reduced, so that the torsion of the vibration isolation device 6 is also reduced if necessary. As a result, the resulting torque applied to the vibration isolation device 6 is pressed below the maximum value M _max and has z. B. the course 36 shown in FIG. 2. As a result, this is similar to a harder vibration isolating device 6 .

The control device 24 in FIG. 1 determines, as described above, the instantaneous rotation or relative angle Sekund between the primary and secondary sides of the vibration isolation device 6 , calculates the torque curve of the desired portion 32 and the exciter portion 30 and determines it with the aid of data of M _max stored in a memory as to whether an attack is imminent. If this is the case, the pulse inverter 26 generates an actuating signal for controlling the electrical machine 4 , which applies an additional torque to reduce the torsion of the vibration isolation device 6 to the cure shaft 2 .

Other control options of the arrangement in Fig. 1 will be illustrated in the following Figs. 3 and 4 veran based on the characteristic curve (torque-rotation angle) according to. The solid line A corresponds to the specific spring characteristic of the elastic coupling element 18 , which depends on the material, geometry, size, etc. In the case of an advantageous soft tuning, the elastic coupling element is chosen to be correspondingly soft, ie flat characteristic curve. If the electric machine is now controlled so that an excitation torque on one side of the vibration isolation device is overlaid in phase with a positive or negative additional torque on the opposite side, then the torsion of the vibration isolation device, hence the angle of rotation ϕ between the primary and secondary side, each enlarged or reduced according to the sign of the additional torque. If the additional torque applied is proportional to the excitation torque applied to the vibration isolating device 6 (as discussed above in FIG. 2), the shape of the spring characteristic curve A is retained, only the slope of the characteristic curve becomes steeper or flatter, as in FIG. 3 with dashed line B (same sign as the excitation moment) or line C (opposite sign to the excitation moment). If the applied torque differs from the excitation torque by a non-constant factor, the shape of the spring line A is also changed, as illustrated by FIG. 4. The characteristic curve A corresponds in turn to the speci fi c spring characteristic of the elastic coupling element 18 . In order to avoid that the vibration isolating device 6 comes into contact with large excitation amplitudes, the electric machine 4 applies a torque with the same sign as the excitation torque, which increases disproportionately with increasing torsion of the vibration isolating device 6 , ie with increasing angle of rotation ϕ. The effective spring characteristic curve then has the curve D shown in FIG. 4 and only asymptotically approaches the limit value ϕ. In addition to the limit value ϕ _max for the maximum permissible rotation angle (stop angle), an initiation value ϕ _{i is also} stored in the control device 24 , which is smaller than the limit value and at which an actuating signal for the electrical machine 4 is already generated. As a result, the Schwungsungsisoliereinrich device 6 is hereby tuned harder at a large angle of rotation ϕ.

The electrical machine 4 can also be controlled so that it makes the characteristic curve linear. For this purpose, after reaching a predetermined initiation value in phase with an excitation torque, such time-varying additional moments with opposite signs apply that the effective spring characteristic curve E shown in FIG. 4 results. Then the vibration isolation device 6 for large excitation amplitudes has a lower spring stiffness compared to the specific spring characteristic curve A of the elastic coupling element 18th As a result, the vibration isolation device 6 is then made softer.

Claims (16)

1. Vibration isolation device with:

• - At least one coupled with a primary drive drive train with an input shaft ( 2 ) and an output shaft ( 10 );
• - One of the input shaft ( 2 ) and the output shaft ( 10 ) torsionally elastic coupling vibration isolation device ( 6 );
• - An electrical machine ( 4 ), the rotor ( 14 ) with the input shaft ( 2 ) or from the output shaft ( 10 ) rotatably connected and the stator ( 12 ) can be fixed against rotation, characterized in that
• - A control device ( 24 ) controls the electrical machine ( 4 ) so that it applies such time-varying torques to the input shaft ( 2 ) or the output shaft ( 10 ) that the induced by the other shaft ( 10 or 2 ) Torsion of the Schwungsungsisolierein direction ( 6 ) is reduced or enlarged.

2. Apparatus according to claim 1, characterized in that the electrical machine ( 4 ) in the drive train egg nes motor vehicle between the internal combustion engine and transmission is arranged in front of the vibration isolation device ( 6 ). 3. Apparatus according to claim 1 or 2, characterized in that the control device ( 24 ) uses the torsion of the Schwingungsisolierein direction ( 6 ) itself as a control variable. 4. Apparatus according to claim 1 or 2, characterized in that the control device ( 24 ) as a control variable characterizing the torsion size, namely the torque of the input shaft ( 2 ) and / or the output shaft ( 10 ) or the difference between these two torques used. 5. Apparatus according to claim 3 or 4, characterized in that the control device comprises:

• - At least one angle encoder ( 30 ) for measuring the torsion of the vibration isolation device ( 6 ) or a torque sensor for measuring the torque of the input shaft and / or the output shaft or the difference between these two torques; and
• - A processing device ( 26 ) for generating manipulated variables for the electrical machine ( 4 ), which acts on the movement of the input shaft ( 2 ) or the output shaft ( 10 ).

6. Device according to one of the preceding claims, characterized in that the vibration isolation device ( 6 ) has at least two basic elements ( 14 , 20 ), of which one basic element ( 14 ) on the drive side and the other basic element ( 20 ) arranged on the drive side and the two basic elements ( 14 , 20 ) via one or more elastic coupling elements ( 18 ), in particular helical, spiral or rubber springs, are coupled in a torsionally elastic manner. 7. The device according to claim 6, characterized in that one or more flywheels are arranged on one or each of the basic elements ( 14 , 20 ). 8. Device according to one of the preceding claims, characterized in that the vibration isolation device ( 6 ) in the rotor ( 14 ) of the electrical machine ( 4 ) is integrated. 9. Device according to one of the preceding claims, characterized in that the control device ( 24 ) controls the electrical machine ( 4 ) so that it as a starter of an internal combustion engine, as a generator, as a generator vehicle brake, as a drive for a vehicle or as an active damper for Torque fluctuations of that shaft ( 2 or 10 ), with which cher the rotor ( 14 ) is connected, is used. 10. A method of operating a device for vibration isolation according to one of the preceding claims, in which the electric machine ( 4 ) applies such torque that changes over time to the input shaft ( 2 ) or the output shaft ( 10 ) that the vibration isolation device ( 6 ) for torques induced by the other shaft ( 10 or 2 ) increased or decreased effective spring stiffness. 11. The method according to claim 10, wherein as a control variable for characterizing the on the Schwingungsisolierein direction ( 6 ) applied to the torsion of the vibration isolation device ( 6 ) and / or the torque of the input shaft ( 2 ) or the output shaft ( 10 ) or the difference thereof two torques is measured and control variables for controlling the electrical machine ( 4 ) are derived therefrom. 12. The method according to claim 10 or 11, wherein the torques applied by the electrical machine ( 4 ) to the input shaft ( 2 ) or the output shaft ( 10 ) are proportional to the excitation torques of the other shaft ( 10 or 2 ) and the like or have the opposite sign. 13. The method according to claim 10 or 11, wherein the torques applied by the electrical machine ( 4 ) to the input shaft ( 2 ) or the output shaft ( 10 ) are a factor dependent on the instantaneous torsion from the excitation torques of the other shaft ( 10 or 2 ) differs. 14. The method according to claim 13, wherein the torques applied by the electrical machine ( 4 ) increase with increasing torsion and have opposite signs as the excitation torques that the vibration isolating device has a substantially linear spring characteristic. 15. The method according to claim 13, wherein the torques applied by the electric machine ( 4 ) increase with increasing torsion and have the same sign as the excitation torques such that the torsion of the vibration isolation device ( 6 ) does not exceed a predetermined limit value. 16. The method of claim 15, further comprising the following steps:

• - Determining a maximum permissible value (limit value) for the torsion of the vibration isolating device ( 6 ) or for a variable characterizing the torsion and a corresponding initiation value which is smaller than the limit value;
• - Detection of actual values of the torsion or of the quantity characterizing the torsion and comparison of the actual values with the corresponding initiation value; and generating an actuating signal for applying such time-varying torques when the initiation value is exceeded that the torsion of the vibration isolation device ( 6 ) approaches the predetermined limit value asymptotically.