CN116573006A

CN116573006A - Rail vehicle chassis with axle control

Info

Publication number: CN116573006A
Application number: CN202310142668.9A
Authority: CN
Inventors: R·施奈特; I·科瓦契奇
Original assignee: Liebherr Transportation Systems GmbH and Co KG
Current assignee: Liebherr Transportation Systems GmbH and Co KG
Priority date: 2022-02-10
Filing date: 2023-02-09
Publication date: 2023-08-11
Also published as: EP4227188A1; JP2023117388A; DE102022103096A1

Abstract

The invention relates to a chassis of a rail vehicle, having an axle and a device for controlling the axle, wherein the device comprises a fluid actuator coupling the axle with the chassis, and by means of which the steering angle of the axle can be adjusted. The chassis comprises a damping device according to the invention, which has a frequency-dependent dynamic stiffness but no static stiffness and which couples the axle to the chassis in parallel to the actuator. The invention also relates to a device for controlling the axle of a chassis according to the invention and to a rail vehicle having a chassis according to the invention.

Description

Rail vehicle chassis with axle control

Technical Field

The present invention relates to a chassis of a rail vehicle according to the preamble of claim 1 and to a device for controlling the axle of such a chassis according to the preamble of claim 14.

Background

In rail vehicles, the contour of the wheels generally results in the wheel set of the chassis running in a sinusoidal manner during travel. If the axle is not firmly connected to the chassis frame, the wheel set will not run stably at high speeds.

DE 102017002926A1 discloses a hydraulic actuator unit for active wheel or wheel set control of a chassis of a rail vehicle. Such an actuator unit is unique in its cylindrical basic shape, whereby a conventional shaft steering bearing with the actuator described above can be directly replaced. In addition, the actuator is unique in that it has no base static stiffness. Thus, no energy or force is required to operate the actuator. However, the absent base stiffness can have a negative impact in the event of a failure that leads to a complete oil loss due to leakage. In this case, the axle of the rail vehicle is no longer firmly connected to the chassis, so that unstable operation of the wheel set may occur.

Furthermore, elastic bearings or hydraulic bushings for damping the coupling of the axle to the chassis are known. However, they are not actively adjustable themselves and also have a basic static stiffness, thus providing a certain residual stiffness even in case of oil loss of the hydraulic bushing, thus maintaining a safety function.

In general, the drive wheels do not provide adequate driving safety for the control system in certain fault situations, especially at higher driving speeds.

Disclosure of Invention

The present invention therefore aims to provide a drive wheel or wheel set control which overcomes the above-mentioned disadvantages.

According to the invention, the object is achieved by a chassis having the features of claim 1 and by an apparatus having the features of claim 14. Advantageous embodiments of the invention result from the dependent claims and the following description.

The invention thus proposes in one aspect a chassis of a rail vehicle having an axle and a device for controlling the axle, wherein the device comprises a fluid actuator which couples the axle with the chassis and by means of which the steering angle of the axle can be adjusted. The axle may be part of the wheelset of the chassis or may represent the wheelset itself.

According to the invention, the chassis comprises damping means coupling the axle with the chassis in parallel to the actuator. The term "parallel" is not to be understood in a geometric sense, but rather in an effect technical sense. The damping device according to the invention is peculiar in that it has a frequency dependent dynamic stiffness or equivalent stiffness but no static stiffness. In other words, the damping device has a stiffness that depends on the excitation or vibration frequency (stiffness particularly increases with the excitation frequency), while in a static situation there is no base stiffness, so that in this case no force needs to be applied. This means that the actuator for adjusting the steering angle of the axle does not have to counter the basic static stiffness of the damping device, but only has to counter its dynamic stiffness, which results in a significant reduction of the energy consumption for positioning the axle.

The parallel arrangement of the actuator and the damping device according to the invention allows the drive wheel pair control to be used also at high speeds, since this ensures driving safety even in case of failure. The actuators known from the prior art, for example DE 102017002926A1, can be used here without the need to make the wheel set control system safe by means of complex modifications.

The actuator may be a pneumatic or hydraulic actuator, preferably a hydraulic actuator.

The feature "the equivalent stiffness of the damping means depends on the frequency" is to be interpreted broadly and is not limited to a specific form of correlation. In the simplest case, this can simply mean that the stiffness at zero excitation frequency (static case) is also zero (base stiffness vanishes), whereas the stiffness at frequencies above zero takes on the value of non-vanishing. This may be a constant value, for example. A linear or nonlinear curve of the stiffness depending on the excitation frequency can also be considered. However, the equivalent stiffness preferably increases with the excitation frequency, in particular linearly, to provide sufficient stiffness at high driving speeds accompanied by higher excitation frequencies.

In a possible embodiment, it is provided that the actuator has a first operating mode in which it is used as a passive damping element with a frequency-dependent dynamic stiffness, wherein the actuator in particular has no static stiffness. In the first mode of operation, the actuator is used only for passive damping of the axle, wherein the damping is provided parallel to the damping means. The stiffness of the actuator and the damping device are advantageously added here.

In a second operating mode, the actuator is used as an actuating mechanism, by means of which the steering angle of the wheel axle is actively adjustable.

Alternatively, the actuator may have a third mode of operation in which the actuator is stationary, in particular fluid blocking. This can be used, for example, during active traction of the rail vehicle or while maintaining a moved position. Thus, in the third mode of operation, the actuator is in particular not adjustable and/or does not have a primary damping function.

In a further possible embodiment, provision is made for the different operating modes of the actuator to be selected or activated by means of a control valve. The control valve is switchable between operating modes. The control valve may be a hydraulic valve, such as a directional valve or a valve assembly.

Preferably, the control valve is switchable by a control unit. To this end, the control unit may preferably receive signals from one or more sensors and switch the control valve to a specific switching position corresponding to a specific operation mode of the actuator based on these signals.

The control valve may connect a fluid input and output of the actuator, in particular connected to a respective fluid chamber of the actuator, to a fluid source, i.e. the control valve switches between the fluid source and the actuator. The fluid source may include a hydraulic motor and one or more hydraulic pumps. In the case of a pneumatic actuator, the fluid source may include one or more high pressure accumulators.

In a second mode of operation, the fluid source is preferably connected to the fluid input and output ports of the actuator so that a desired adjustment or positioning of the actuator can be achieved by a corresponding pressure load.

In the first mode of operation, the fluid input and output of the actuator may be separate from the fluid source and/or connected to each other via a throttle device. The throttle device may cause a corresponding damping action of the actuator in the first operating mode, like a hydraulic shock absorber or shock absorber.

In an optional third mode of operation, the fluid input and output ports of the actuator may be separate from the fluid source and from each other.

In a further possible embodiment, it is provided that the control unit is configured to switch the control valve to a switching position corresponding to the first operating mode during straight running of the rail vehicle. Alternatively or additionally, the control unit may be arranged to switch the control valve to a switching position corresponding to the second operating mode during cornering of the railway vehicle. Alternatively or additionally, the control unit may be arranged to switch the control valve to a switching position corresponding to the third operating mode when a defined state is detected, which defined state may be for example traction running of the rail vehicle or a specific position, but may also be for example a manual input by a driver or operator of the rail vehicle.

Preferably, the control unit is further arranged to automatically detect straight running or cornering running (or the above defined conditions for said third operating mode) on the basis of the signals of at least one sensor and to switch and/or adjust said control valve accordingly.

Signals of a travel sensor, an angle sensor, a pressure sensor, a speed sensor, an acceleration sensor, etc. are generally used for controlling and/or adjusting the control valve or the actuator (i.e. on the one hand for selecting the respective operating mode, but also for controlling the wheel axle in the second operating mode, i.e. for targeted control of the actuator for positioning the wheel axle). For example, the running speed or the lateral acceleration may be measured. It is also conceivable to determine the traction by measuring the longitudinal movement between the chassis and the body or bodies rotatably connected to said chassis. The actuation force may be detected by a pressure measurement in the actuator. It is also conceivable to carry out the pressure measurement in the damping device provided to the control unit by means of an integrated pressure sensor. This can be combined with corresponding pressure measurements in the actuator, if necessary.

In a further possible embodiment, it is provided that the damping device comprises at least one passive damping element. The damping element preferably represents a maxwell Wei Ti or maxwell element (i.e. a series of hook springs and dampers in a rheological model). Preferably, the entire damping device represents a maxwell element.

The damping device may comprise only a single passive damping element or a plurality of such passive damping elements in series. In the latter case, one or more damping elements may be activated or switched on as necessary, possibly via the above-mentioned control unit or via a separate controller.

In a further possible embodiment, it is provided that the damping element of the damping device is designed as a fluid, in particular hydraulic, shock absorber and preferably does not comprise a mechanical spring element. Such damping elements have no base static stiffness, for example, as compared to conventional hydraulic bushings.

According to the invention, the damping device itself does not have a basic static stiffness. However, it is conceivable to use the damping device together with a hydraulic bushing, for example to mount the damping device on the chassis and/or on the axle. In this case, the hydraulic bushing can be designed with a lower residual stiffness, which significantly improves its performance.

In a further possible embodiment, it is provided that the damping element of the damping device is permanently connected parallel to the actuator, i.e. its damping effect or stiffness permanently influences the wheel axle parallel to the actuator. In case of failure of the actuator, e.g. leakage, the damping element may still provide sufficient stiffness for the bearings of the axle. Only in case of faults or leaks (double faults) in the actuator and the parallel damping elements, which are highly unlikely to occur, will result in complete failure, however this represents an acceptable residual risk.

Alternatively or additionally, the damping element of the damping device may be switched on as required. This may result, for example, from a desired damping behavior under certain conditions (e.g. a certain driving speed). Preferably, however, the damping element may be switched on when said failure to the actuator is detected. Such a fault is present in particular when the actuator leaks, which is preferably registered by a pressure drop detected by means of a pressure sensor provided in the actuator. In such leakage situations, the individual actuators do not provide sufficient stiffness to support the axle, which can lead to unstable wheel operation, especially at high driving speeds. In this case, the switched-on damping element can "take over" and provide sufficient stiffness.

In a further possible embodiment, it is provided that the actuator comprises a pressure sensor, by means of which a pressure drop in the actuator can be detected, wherein the switchable damping element is preferably coupled fluidically (in particular hydraulically) to the actuator in such a way that it automatically "activates" or switches on in the pressure drop.

In a further possible embodiment, it is provided that the damping device couples the axle to the chassis in parallel to the actuator, so that the stiffness of the actuator and the damping device add, wherein the system consisting of the actuator and the damping device preferably has no static stiffness or base stiffness. The combination of the actuator and the damping means may for example have a dynamic stiffness corresponding to a conventional hydraulic bushing (except for a residual stiffness in the hydraulic bushing which is greater than zero and equal to zero in the device of the invention).

In a further possible embodiment it is provided that the axle is pivotably mounted on a wheel suspension, wherein both the actuator and the damping device are coupled to the wheel suspension. Preferably, the actuator is connected to a rocker arm of the wheel suspension. Alternatively or additionally, the damping device may be connected to a axle box cover of the wheel suspension. It is also conceivable that the actuator and the damping device are attached to a common rocker arm.

Preferably, the damping means is connected by means of the axle housing cover, which in turn is connected to the rocker arm. The axle box cover is connected with the damping device, so that the subsequent refitting of the existing chassis is facilitated. In particular, during subsequent retrofitting, the entire rocker arm or wheel suspension adjustment can be bypassed.

In a further possible embodiment, it is provided that the longitudinal axis of the damping device extending in the damping direction intersects the rotational axis of the axle (i.e. the longitudinal axis extending centrally along the axle). Due to this structure, no additional moment is applied by the damping means. In particular, when the damping device as described above is connected by the axle box cover, no additional moment is applied to the rocker arm.

In a further possible embodiment, it is provided that at least one travel sensor or position sensor is integrated into the actuator and/or the damping device, by means of which the ejection length of the actuator can be determined preferablyAnd/or the ejection length of the damping device and/or the position (e.g. angular position) of the axle, and may in particular be provided to a control unit for controlling and/or adjusting the axle position. The stroke sensor of the drive wheel pair control is integrated into the damping device, which can protect the sensor from environmental conditions in the vicinity of the wheel pair. Furthermore, the travel sensor is easier to replace in the event of a sensor failure than if it were integrated into the actuator. This reduces maintenance costs and improves reliability.

In another possible embodiment, provision is made for the actuator to comprise: a shaft attached to the chassis, a fluid-synchronized cylinder, and a housing coupled to the axle that is movable according to movement of the fluid-synchronized cylinder relative to the shaft. Preferably, the synchronizing cylinder is designed or integrated in the shaft and comprises a piston with a piston rod penetrating the shaft on each of its two flat sides. Each piston rod passing through the shaft body is connected to the housing, in particular at its end facing away from the piston surface, by a piston spring element.

Thus, with such an actuator it is possible to cause a movement of the housing by adjusting the synchronizing cylinder or moving the piston rod, which movement in turn is used to cause a pivoting movement of the axle coupled to the actuator. In this case, the axle is typically attached to the chassis such that relative movement of the housing with respect to the axle can be used to deflect the travel of the axle.

Preferably, the actuator corresponds to the actuator disclosed in DE 102017002926A1, wherein each of the embodiments described is applicable to the actuator of the present invention. The teaching of DE 102017002926A1 regarding possible designs of the actuator is fully incorporated in the present disclosure.

The invention also relates to a device for controlling the axle of a chassis according to the invention. The device comprises a fluid actuator according to the invention and a damping device according to the invention, which can be designed according to one of the exemplary embodiments described above. The actuator may be coupled to the axle on the one hand and to the chassis on the other hand. The damping device may be coupled parallel to the actuator on the one hand to the axle and on the other hand to the chassis. This obviously results in the same advantages and characteristics as the chassis of the present invention, and thus duplicate description is omitted.

The damping means may represent a separate component from the actuator. However, it is also conceivable that the damping device is integrated into the actuator, or that the damping device and the actuator are integrated into a common housing. This not only relates to the device according to the invention, but also to the chassis according to the invention in general. This will result in easier assembly or disassembly, for example to simply retrofit the chassis of an existing rail vehicle.

The invention also relates to a rail vehicle having a chassis according to the invention. Here, the advantages and characteristics are obviously also the same as those of the chassis according to the present invention, and thus duplicate description is omitted.

Drawings

Other features, details and advantages of the invention result from the embodiments explained below with reference to the drawings. The drawings show:

FIG. 1 is a schematic plan view of a chassis according to the present invention according to an embodiment;

FIG. 2 is a rheologically equivalent circuit diagram of an embodiment of the device according to the invention, in which the actuator is in a first operating mode (left diagram) and shows a schematic diagram of the corresponding dynamic stiffness (right diagram);

FIG. 3 is a schematic diagram of the rheological equivalent circuit diagram of a conventional hydraulic bushing (left) and its dynamic stiffness (right);

FIG. 4 is a view of FIG. 2 in the event of an actuator leak;

FIG. 5 is a view of FIG. 3 in the event of a hydraulic bushing leak;

FIG. 6 is a view of FIG. 2 in the event of a damping device leak;

FIG. 7 is a view of FIG. 2 in the event of simultaneous leakage of the actuator and damping device;

FIG. 8 is a rheologically equivalent circuit diagram of the device according to the invention of FIG. 2, in which the actuator is in a third operating mode; and

fig. 9 is a rheological equivalent circuit diagram of the device according to the invention according to fig. 2, wherein the actuator is in a second operating mode.

Detailed Description

Fig. 1 shows a schematic plan view of an embodiment of a chassis 10 according to the present invention. The figure shows the body or a part of the body 1 of a rail vehicle during cornering (the track is shown as a curve). The illustrated part of the body 1 comprises a chassis 10 with two steerable wheel axles 12, which together form a wheel set of the chassis 10. Each axle 12 comprises two wheels rigidly or non-rotatably connected to each other by an axle and supported on a rail. The axle 12 or wheel set is steered or controlled by active wheel set control, which will be described in more detail below.

In the embodiment shown here, each axle 12 is adjustable on one side by an actuator 22, wherein the axles 12 are coupled to the actuator 22 on different sides. Alternatively, the axle 12 may be coupled to the actuator 22 on each side. The primary objective of the capstan pair control is to apply pressure to the actuator 22, thereby rotating the axle 12 about its vertical axis (hochchsen).

In the illustrated embodiment, the actuator 22 is a hydraulic actuator. Preferably, the actuator is an actuator described in DE 102017002926 A1. Of course, other actuators 22 may be used for drive wheel pair control.

The actuator 22 is attached on the one hand to the chassis frame 18 of the chassis 10, which is only schematically indicated with lines in fig. 1. The movable portions of the actuators 22 are respectively coupled with the rocker arms 14 of the wheel suspensions of the associated axle 12. The respective axle 12 is thereby pivoted by actuating an actuator 22 coupling the respective rocker arm 14 with the chassis frame 18.

On the side opposite the actuator 22, each wheel axle 12 is also connected to the chassis frame 18 by means of a further rocker arm 14 and a bearing 19. The bearing 19 may be, for example, a mechanical bearing or a hydraulic bushing.

In accordance with the present invention, a damping device 24 or axle damper 24 (both terms are used synonymously hereinafter) is disposed parallel to each actuator 22, the damping device or axle damper also coupling the swing arm 14 to the chassis frame 18. Thus, each axle 12 is mounted on the chassis 10 by means of a device 20 comprising an actuator 22 and a damping device 24 and is actively adjustable. At the same time, the device 20 serves to buffer the respective wheel axle 12 to ensure smooth running.

As an alternative to the embodiment shown here, the two axles may also be coupled by a common actuator 22, wherein the actuator may additionally be attached to the chassis 10. In this case, the damping device 24 parallel to the actuator 22 will also be coupled with both axles.

The additional damping device 24 according to the invention is peculiar in that it does not have a basic static stiffness, but only a frequency dependent dynamic or equivalent stiffness. The stiffness increases as the excitation frequency increases. The actuator 22 thus does not have to oppose the residual static stiffness of the damping device 24, compared to a damper with residual static stiffness (as is the case with conventional hydraulic bushings), so that only a lower force is required to adjust the axle 12.

The damping device 24 is also attached to the chassis frame 18 and coupled to the axle 12 through the axle housing cover 16, which in turn is connected to the rocker arm 14. The longitudinal axis of the damping device 24 intersects the axle 12 such that no additional moment is applied to the rocker arm 14 by the damping device 24.

The attachment of the damping device 24 via the axle housing cover 16 facilitates subsequent retrofitting of the existing chassis 10. The adjustment of the entire rocker arm 14 may be bypassed during subsequent retrofitting. However, it is also possible that the damping device 24 is connected to the rocker arm 14 without intersecting the axle 12 and the axis of the damping device 24.

In case the wheel set control requires a position detection on the actuator 22, a corresponding sensor system, for example in the form of a solution, may be integrated in the parallel arranged damping device 24. This makes it possible to protect the travel sensor and the position sensor from environmental conditions in the vicinity of the wheel set and to facilitate replacement of the sensors.

The damping device 24 may comprise a single damping element or a combination of different damping elements. They may all be permanently connected in parallel with the actuator 22 or one or more damping elements may be activated or connected in case of failure of the actuator 22, in particular in case of fluid leakage.

Fig. 2 shows in a left diagram a rheologically equivalent circuit diagram of an embodiment of the device 20 of the invention comprising an actuator 22 and a damping device 24, and in a right diagram schematically a corresponding equivalent stiffness c of the actuator 22 (upper dashed line) \damping device 24 (lower dashed line) and combinations thereof (solid line) as a function of the excitation frequency f _eq 。

The actuator 22 in this embodiment has three modes of operation: in a first mode of operation, shown in fig. 2, the actuator 22 represents a passive damping element having an equivalent stiffness that is frequency dependent and zero residual stiffness. The first operating state or operating mode is preferably used when the rail vehicle is traveling straight. The actuator 22 is moved to the selected switching position by the wheel-set controlled external valve circuit. In this switching state, the actuator 22 functions as a maxwell element (maxwell element).

Fig. 3 shows an equivalent circuit diagram of a conventional hydraulic bushing 30 for comparison. As shown in the right hand graph of fig. 3, the hydraulic bushing 30 has an equivalent stiffness that increases with increasing frequency and a residual greater than zeroRigidity. The zero stiffness of the hydraulic bushing 30 corresponds to the base static stiffness c ₂ 。

In the present embodiment, the equivalent stiffness of the device 20 according to the invention, i.e. the actuator 22 and the damping device 24 arranged in parallel, is chosen such that, except for the stiffness at zero point (in the device according to the invention equal to zero), the equivalent stiffness is equivalent compared to the equivalent stiffness of the hydraulic bushing 30.

If there is a leakage of oil in the actuator 22 in the device 20 according to the invention, the damping is still provided by the parallel shaft damper 24. Due to its equivalent stiffness, sufficient stiffness or damping may be provided, especially at high driving speeds, to avoid running the wheel set in a sinusoidal manner.

This failure is shown in the equivalent circuit diagram of fig. 4. The equivalent stiffness curve (right) shows that the hydraulic bushing 30 maintains the static stiffness c ₂ And in the event of a leak at the actuator 22, the equivalent stiffness of the shaft damper 24 remains unchanged. In the event of a leak at the actuator 22, the unstable wheel set is counteracted by the equivalent stiffness of the axle damper 24. Since unstable operation can only occur at high speeds (i.e. high excitation frequencies), a (equivalent) stiffness is only required at higher frequencies. On the other hand, the hydraulic bushing 30 uses its base static stiffness c in case of leakage due to its design ₂ To counteract wheel sets that become unstable.

Due to the parallel arrangement of the actuator 22 and the axle damper 24 according to the invention, in case of a leakage failure, the wheel set control system has the following states:

i) Leakage in actuator 22 (see fig. 2): the load path through the actuator 22 is omitted. The axle damper 24 produces an equivalent stiffness by external excitation of the wheel set, which ensures stable operation. The equivalent stiffness value should correspond to at least the static stiffness value of the hydraulic bushing in the relevant speed range. This results in a situation similar to the hydraulic bushings currently established.

ii) leakage in the damping device 24 (see fig. 6): the load path through the shaft damper 24 is omitted. When the rail vehicle is traveling straight, the actuator 22 takes over power flow (kraft flush) and stabilizes the wheel set.

iii) The actuator 22 and the damping device 24 leak simultaneously (see fig. 7): this case assumes a double failure of two devices or components independent of each other. Currently, the associated residual risk has been widely accepted, such as yaw dampers on high speed trainsIs a dual design of (c).

The realization of the drive wheel pair control by the parallel arrangement of the actuator 22 and the damping means 24 has the advantage that the actuator 22 only has to act against the damping means 24 during positioning of the axle 12. Conversely, when using the hydraulic bushing 30, the actuator will have to overcome the damping and base stiffness c of the hydraulic bushing 30 during positioning ₂ This would require significantly more energy consumption for wheel set positioning.

A second mode of operation of the actuator 22 is shown in fig. 9. Here, the actuator can be actively adjusted and thus the positioning of the coupled axle 12 can be changed in a targeted manner. This can also be achieved by means of an external valve circuit controlled by the wheel set. For this purpose, the actuator 22 may have a shaft body fixedly connected to the chassis frame 18 and in which a hydraulic synchronization cylinder is formed which, when actuated, adjusts the wheel axle 12, as described for example in DE 102017002926 A1.

In the third mode of operation, the actuator 22 is hydraulically blocked (see fig. 8). The operating state may be employed, for example, during active traction or while maintaining a moved position.

The control and/or regulation of the external valve circuit is preferably performed automatically on the basis of the sensor data. In particular, straight-line travel or cornering travel is automatically detected, and the valve circuit is controlled and/or regulated accordingly.

Alternatively, the damping function of the damping device 24 may be integrated directly into the actuator 22. However, due to the limited installation space conditions in the actuator 22, it is preferable to arrange it separately, and the damping means 24 are shown outside the actuator 22 in fig. 2, 4 and 6 to 9, respectively.

List of reference numerals:

1 vehicle body

10 chassis

12 wheel axle

14 rocker arm

16-axle box cover

18 chassis frame

19 bearing

20 device

22 actuator

24 damping device/shaft damper

30 hydraulic bushing.

Claims

1. A chassis (10) of a rail vehicle having an axle (12) and a device (20) for controlling the axle, wherein the device (20) comprises a fluid actuator (22) which couples the axle (12) with the chassis (10) and by means of which the steering angle of the axle (12) can be adjusted,

it is characterized in that the method comprises the steps of,

damping means (24) having a frequency-dependent dynamic stiffness but no static stiffness and coupling the axle (12) with the chassis (10) in parallel to the actuator (22).

2. Chassis (10) according to claim 1, wherein the actuator (22) is a passive damping element in a first mode of operation, having a frequency-dependent dynamic stiffness, but in particular no static stiffness, and is used as an actuator in a second mode of operation, by means of which the steering angle of the axle (12) can be adjusted, wherein the actuator (22) is preferably fixed, in particular fluid-blocked, in a third mode of operation.

3. Chassis (10) according to claim 2, wherein the different modes of operation of the actuator (22) can be activated by a control valve, in particular connecting a fluid input and output of the actuator (22) with a fluid source, wherein the control valve is preferably switchable by a control unit.

4. Chassis (10) according to claim 3, wherein the control unit is arranged to switch the control valve to a switching position activating a first operation mode when the rail vehicle is traveling straight and/or to a switching position activating a second operation mode when the rail vehicle is traveling turning, wherein the control unit is preferably further arranged to automatically detect straight traveling or turning traveling based on signals of at least one sensor and to switch the control valve accordingly.

5. Chassis (10) according to any of the preceding claims, wherein the damping means (24) comprises at least one passive damping element.

6. Chassis (10) according to claim 5, wherein the damping element of the damping device (24) is designed as a fluid shock absorber, in particular as a hydraulic shock absorber.

7. Chassis (10) according to claim 5 or 6, wherein the damping element of the damping device (24) is permanently parallel to the connection to the actuator (22) and/or the damping element of the damping device (24) can be connected when required, in particular in the event of a malfunction of the actuator (22) which can be registered, preferably by a pressure drop detected by a pressure sensor arranged in the actuator (22).

8. Chassis (10) according to claim 7, wherein the actuator (22) comprises a pressure sensor by means of which a pressure drop in the actuator (22) can be detected, wherein an activatable damping element is preferably fluidically coupled to the actuator (22) such that the damping element is activated automatically upon pressure drop.

9. Chassis (10) according to any of the preceding claims, wherein the damping device (24) couples the axle (12) with the chassis (10) in parallel to the actuator (22) such that the stiffness of the actuator (22) and the damping device (24) add, wherein the system consisting of the actuator (22) and the damping device (24) preferably does not have a static stiffness.

10. Chassis (10) according to any of the preceding claims, wherein the axle (12) is rotatably mounted on a wheel suspension, the actuator (22) and the damping device (24) being both coupled to the wheel suspension, wherein the actuator (22) is preferably connected to a rocker arm (14) of the wheel suspension and/or the damping device (24) is connected to a axle housing (16) of the wheel suspension.

11. Chassis (10) according to any of the preceding claims, wherein a longitudinal axis of the damping device (24) extending in a damping direction intersects a rotation axis of the axle (12).

12. Chassis (10) according to any of the preceding claims, wherein at least one stroke sensor is integrated into the actuator (22) and/or the damping device (24), preferably by means of which the ejection length of the actuator (22) and/or the ejection length of the damping device (24) and/or the position of the axle (12) can be determined and in particular provided to a control unit for controlling the axle (12).

13. The chassis (10) according to any one of the preceding claims, wherein the actuator (22) comprises: -a shaft body attached to the chassis (10), -a fluid synchronizing cylinder, and-a housing coupled to the axle, movable in accordance with the movement of the fluid synchronizing cylinder relative to the shaft body, wherein the synchronizing cylinder is preferably designed in the shaft body and comprises a piston having on both flat sides thereof a piston rod penetrating the shaft body, which piston rod is connected to the housing by means of a piston spring element, in particular at its end facing away from the piston surface.

14. Device (20) for controlling an axle (12) of a chassis (10) according to any of the preceding claims, comprising a fluid actuator (22) which is coupleable with the axle (12) on the one hand and with the chassis (10) on the other hand, and by means of which the steering angle of the axle (12) can be adjusted.

It is characterized in that the method comprises the steps of,

damping means (24) having a frequency-dependent dynamic stiffness but no static stiffness and being coupled to the axle (12) on the one hand and to the chassis (10) on the other hand parallel to the actuator (22).

15. A rail vehicle having a chassis (10) according to any one of claims 1 to 13.