Rail vehicle chassis with a device for controlling a wheel axle

Abstract

The invention relates to a chassis of a rail vehicle with a wheel axle and a device for controlling the wheel axle, wherein the device comprises a fluidic actuator which couples the wheel axle to the chassis and by means of which the steering angle of the wheel axle is adjustable. According to the invention, the chassis includes a damping device which has a frequency-dependent dynamic stiffness but no static stiffness and couples the wheel axle to the chassis parallel to the actuator. The invention further relates to a device for controlling a wheel axle of a chassis according to the invention and to a rail vehicle with a chassis according to the invention.

Description

[0001] Rail vehicle chassis with a device for controlling a wheel axle The present invention relates to the chassis of a rail vehicle according to the preamble of claim 1 and to a device for controlling a wheel axle of such a chassis according to the preamble of claim 13.

[0002] In rail vehicles, the profiled shape of the wheels generally causes the bogie wheelset to sinusoidally roll during travel. If the wheel axles are not rigidly connected to the bogie frame, the wheelset will become unstable at high travel speeds.

[0003] US 2021 / 139057 A1, for example, discloses a hydromechanical wheelset control system for a rail vehicle, comprising a leading wheelset and a trailing wheelset arranged behind the leading wheelset in a direction of travel, the trailing wheelset having the property of assuming a favorable position in a curve of a cooperating bogie frame and rail pair. This wheelset control system known from the prior art is characterized in that a wheelset control connected to the leading wheelset and the trailing wheelset is provided, which is designed to hydraulically deflect the leading wheelset depending on a deflection of the trailing wheelset, preferably by the same amount as the trailing wheelset but in the opposite direction.

[0004] Furthermore, WO 2017 / 157740 A1 discloses a running gear for a rail vehicle with at least one first pair of wheels or at least one first wheelset, as well as with an active wheel control or wheelset control. At least one actuator unit and, in operative parallel connection to the actuator unit, at least one passive elastic bearing with frequency- and amplitude-dependent static and increased dynamic stiffness are arranged on the disclosed running gear. The actuator unit, under quasi-static loading, exerts an adjusting function on the position and, in particular, the orientation of the first pair of wheels or the first wheelset, and the elastic bearing couples the first pair of wheels or the first wheelset with dynamic stiffness.

[0005] DE 10 2017 002 926 A1 discloses a hydraulic actuator unit for active wheel or wheelset control for a rail vehicle chassis. This actuator unit is primarily characterized by its cylindrical basic shape, which allows a conventional axle steering bearing to be directly substituted with the described actuator. Furthermore, the actuator is characterized by the fact that it has no static basic rigidity. Therefore, no energy or force is required to actuate the actuator. However, a lack of basic rigidity has a disadvantage in the event of a failure in which a leak leads to complete oil loss. In In this case, the wheel axles of the rail vehicle are no longer connected to the chassis rigidly enough, which can lead to unstable running of the wheelset.

[0006] Furthermore, elastic bearings or hydraulic bushings are known for dampened coupling of the wheel axles to the chassis. However, these are not actively adjustable and also have a basic static stiffness, so that even in the event of an oil leak from a hydraulic bushing, a certain residual stiffness is still maintained, thus ensuring the safety function.

[0007] Overall, it can be concluded that active wheelset control systems do not provide sufficient driving safety in certain fault cases, especially at higher driving speeds.

[0008] The present invention is therefore based on the object of providing an active wheel or wheelset control which overcomes the aforementioned disadvantages.

[0009] This object is achieved according to the invention by a chassis having the features of claim 1 and a device having the features of claim 13. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0010] Accordingly, a rail vehicle chassis with a wheel axle and a device for controlling the wheel axle is proposed, wherein the device comprises a fluidic actuator that couples the wheel axle to the chassis and by means of which the steering angle of the wheel axle can be adjusted. The wheel axle can be part of a wheelset of the chassis or represent the wheelset itself.

[0011] According to the invention, the chassis comprises a damping device that couples the wheel axle to the chassis parallel to the actuator. The term "parallel" is not to be understood in a geometric sense, but rather in a functional sense. The damping device according to the invention is characterized by having a frequency-dependent dynamic or equivalent stiffness, but no static stiffness. In other words, the damping device has a stiffness that depends on the excitation or vibration frequency (in particular, the stiffness increases with the excitation frequency), whereas in the static case, no basic stiffness is present, so that in this case, no force needs to be applied.This means that the actuator for adjusting the steering angle of the wheel axle does not have to work against the static basic stiffness of the damping device, but only against its dynamic stiffness, which requires significantly less energy to position the wheel axle.

[0012] The parallel arrangement of actuator and damping device according to the invention allows the use of active wheelset control systems even at high speeds, as this reliably ensures driving safety even in the event of a fault. A known actuator from the prior art, for example, from DE 10 2017 002 926 A1, can be used without requiring a complex redesign of the wheelset control system to ensure fail-safe operation.

[0013] The actuator may be a pneumatic or hydraulic actuator, the latter embodiment being preferred.

[0014] The characteristic that the equivalent stiffness of the damping device is frequency-dependent should be interpreted broadly and not limited to a specific form of dependency. In the simplest case, this can simply mean that the stiffness at an excitation frequency of zero (static case) is also zero (vanishing basic stiffness), while the stiffness at frequencies above zero assumes a non-vanishing value. This can, for example, be a constant value. A linear or non-linear curve of the stiffness as a function of the excitation frequency is also conceivable. However, the equivalent stiffness preferably increases with the excitation frequency, in particular linearly, in order to provide sufficient stiffness, especially at high driving speeds associated with higher excitation frequencies.

[0015] According to the embodiment of the invention, the actuator has a first operating mode in which it functions as a passive damping element with a frequency-dependent dynamic stiffness, wherein the actuator, in particular, has no static stiffness. In the first operating mode, the actuator serves only for passive damping of the wheel axle, with the damping effect being provided in parallel with the damping device. The stiffnesses of the actuator and the damping device advantageously add up.

[0016] In a second operating mode, the actuator functions as an actuator by means of which the steering angle of the wheel axle can be actively adjusted.

[0017] Furthermore, according to the invention, the actuator has a third operating mode in which it is fixed, in particular fluidically blocked. This can be used, for example, during active traction of the rail vehicle or while holding a position. In the third operating mode, the actuator is thus, in particular, not adjustable and / or does not have a primarily damping function.

[0018] In one possible embodiment, the various operating modes of the actuator can be selected or activated using a control valve. Switching between the operating modes can thus be done using the control valve. The control valve can be a hydraulic valve, such as a directional control valve, or a valve assembly.

[0019] Preferably, the control valve can be switched by means of a control unit. For this purpose, the control unit can preferably receive signals from one or more sensors and, based on these signals, switch the control valve to a specific switching position corresponding to a specific operating mode of the actuator.

[0020] The control valve can connect the actuator's fluid inlets and outlets, which are connected in particular to corresponding fluid chambers of the actuator, to a fluid source. This means that the control valve is connected between the fluid source and the actuator. The fluid source can comprise a hydraulic motor and one or more hydraulic pumps. In the case of a pneumatic actuator, the fluid source can comprise one or more high-pressure accumulators.

[0021] In the second operating mode, the fluid source is preferably connected to the fluidic inputs and outputs of the actuator so that a desired adjustment or positioning of the actuator can be achieved by applying appropriate pressure.

[0022] In the first operating mode, the fluid inlets and outlets of the actuator can be separated from the fluid source and / or connected to each other via a throttle device. The throttle device can provide a corresponding damping effect of the actuator in the first operating mode, similar to a hydraulic vibration damper or shock absorber.

[0023] In the third operating mode, the fluidic inputs and outputs of the actuator can be separated from the fluid source and from each other.

[0024] In a further possible embodiment, it is provided that the control unit is configured to switch the control valve into a switching position corresponding to the first operating mode when the rail vehicle is traveling straight ahead. Alternatively or additionally, the control unit can be configured to switch the control valve into a switching position corresponding to the second operating mode when the rail vehicle is cornering. Alternatively or additionally, the control unit can be configured to switch the control valve into a switching position corresponding to the third operating mode upon detection of a defined state, which can be, for example, traction travel or a specific position of the rail vehicle, but also a manual input, for example, from the driver or operator of the rail vehicle.

[0025] The control unit is preferably further configured to automatically detect straight-ahead travel or cornering (or the aforementioned defined state for the third operating mode) based on signals from at least one sensor and to switch and / or regulate the control valve accordingly.

[0026] In general, signals from position sensors, angle sensors, pressure sensors, speed sensors, acceleration sensors or the like can be used to control and / or regulate the control valve or actuator (i.e., on the one hand, for selecting the respective operating mode, but possibly also for controlling the wheel axle in the second operating mode, i.e. for the targeted control of the actuator to position the wheel axle). For example, a driving speed or lateral acceleration can be measured. It is also conceivable to determine a traction force by measuring a longitudinal movement between the running gear and a car body or car that is rotatably connected to the running gear. An actuator force can be recorded by means of a pressure measurement in the actuator. It is also conceivable to carry out a pressure measurement in the damping device using an integrated pressure sensor, which is then made available to the control unit. This could, if necessary,combined with a corresponding pressure measurement in the actuator.

[0027] In In another possible embodiment, the damping device comprises at least one passive damping element. This damping element preferably represents a Maxwell body or a Maxwell element (i.e., a series connection of a Hooke's spring and a damper in rheological modeling). Preferably, the entire damping device represents a Maxwell element.

[0028] The damping device can comprise only a single passive damping element or a series connection of several such passive damping elements. In In the latter case, one or more damping elements can be activated or switched on as required, if necessary via the control unit described above or via a separate control unit.

[0029] InIn another possible embodiment, a damping element of the damping device is designed as a fluidic, in particular hydraulic, shock absorber and preferably does not include a mechanical spring element. Such a damping element, unlike a conventional hydraulic bushing, for example, has no static basic rigidity.

[0030] According to the invention, the damping device as such does not have any static basic 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 the wheel axle. In In this case, the hydraulic bushing can be designed with a lower residual stiffness, which significantly increases its performance.

[0031] InAnother possible embodiment provides for a damping element of the damping device to be permanently connected in parallel with the actuator, i.e., its damping effect or stiffness permanently acts on the wheel axle parallel to the actuator. In the event of an actuator failure, such as a leak, the damping element can then still provide sufficient stiffness for supporting the wheel axle. Only in the extremely unlikely event of a failure or leak in the actuator and the parallel damping element (double failure) would a total failure occur, although this represents an acceptable residual risk.

[0032] Alternatively or additionally, a damping element of the damping device can be activated as needed. This can result, for example, from a desired damping behavior under certain conditions, such as a certain driving speed. Preferably, however, the damping element can be activated upon detection of a malfunction of the actuator. Such a malfunction occurs in particular in the case of a leak in the actuator, which can preferably be registered by detecting a pressure drop using a pressure sensor provided in the actuator. In the event of such a leak, the actuator alone cannot provide sufficient stiffness to support the wheel axle, which can lead to unstable wheel running, particularly at high driving speeds. In this case, the activated damping element can "take over" and provide sufficient stiffness.

[0033] 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 fluidically (in particular hydraulically) coupled to the actuator in such a way that it is automatically "activated" or switched on in the event of a pressure drop.

[0034] In another possible embodiment, the damping device couples the wheel axle to the chassis parallel to the actuator in such a way that the stiffnesses of the actuator and the damping device add up. Preferably, the system comprising the actuator and damping device has no static stiffness or basic stiffness. The combination of actuator and damping device can, for example, have a dynamic stiffness equivalent to that of a conventional hydraulic bushing (except for the residual stiffness, which is greater than zero for a hydraulic bushing and equal to zero for the device according to the invention).

[0035] In another possible embodiment, the wheel axle is rotatably mounted on a wheel suspension, with both the actuator and the damping device being coupled to the wheel suspension. Preferably, the actuator is connected to a swing arm of the wheel suspension. Alternatively or additionally, the damping device can be connected to an axle bearing cover of the wheel suspension. It is also conceivable for the actuator and damping device to be attached to a common swing arm.

[0036] Preferably, the damping device is connected via the aforementioned axle bearing cover, which in turn is connected to the swing arm. Connecting the damping device via the axle bearing cover facilitates retrofitting existing chassis. In particular, it avoids the need to adjust the entire swing arm or wheel suspension during retrofitting.

[0037] In another possible embodiment, a longitudinal axis of the damping device running along the damping direction intersects the rotational axis (i.e., the longitudinal axis running centrally along the wheel axle) of the wheel axle. With such a design, no additional torque is applied via the damping device. In particular, with the previously described connection of the damping device via the axle bearing cover, no additional torque is applied to the swing arm.

[0038] In a further possible embodiment, at least one displacement sensor or position sensor is integrated into the actuator and / or the damping device, by means of which sensor an extension length of the actuator and / or an extension length of the damping device and / or a position (e.g. an angular position) of the wheel axle can be determined and in particular can be made available to a control unit for controlling and / or regulating the wheel axle position. Integrating the displacement sensor for the active wheelset control into the damping device makes it possible to protect the sensor from the ambient conditions in the vicinity of the wheelset. Furthermore, in the event of a sensor failure, the displacement sensor is significantly easier to replace than if it were integrated into the actuator. This reduces maintenance costs and increases reliability.

[0039] In another possible embodiment, the actuator comprises an axle body attached to the chassis, a fluidic synchronizing cylinder, and a housing coupled to the wheel axle, which is movable in correspondence with a movement of the synchronizing cylinder relative to the axle body and is coupled to the wheel axle. The synchronizing cylinder is preferably formed in or integrated into the axle body and comprises a piston having a piston rod penetrating the axle body on each of its two flat sides. Each of the piston rods penetrating the axle body is connected to the housing, in particular at its end facing away from the piston surface, via a piston spring element.

[0040] With such an actuator, it is possible to induce a movement of the housing by adjusting the synchronizing cylinder or moving the piston rods, which in turn is used to induce a pivoting movement of the wheel axle coupled to the actuator. The axle body is usually fixed to the chassis, so that a relative movement of the housing relative to the axle body can be used to create a stroke for deflecting the wheel axle.

[0041] Preferably, the actuator corresponds to the actuator disclosed in DE 10 2017 002 926 A1, wherein any of the embodiments described therein is suitable for the actuator of the present invention. The teaching of DE 10 2017 002 926 A1 is fully incorporated into the present disclosure with regard to the possible configuration of the actuator.

[0042] The present invention further relates to a device for controlling a wheel axle of a chassis according to the invention. The device comprises a fluidic actuator according to the invention and a damping device according to the invention, which can be designed according to one of the previously described embodiments. The actuator can be coupled to the wheel axle on the one hand and to the chassis on the other hand. The damping device can be coupled parallel to the actuator to the wheel axle on the one hand and to the chassis on the other hand. This obviously results in the same advantages and properties as for the chassis according to the invention, which is why a repeated description is omitted.

[0043] The damping device can be a separate component from the actuator. However, it is also conceivable for the damping device and actuator to be integrated into a common housing. This applies not only to the device according to the invention, but generally to the chassis according to the invention. This results in even simpler assembly and disassembly, for example, for the purpose of simple retrofitting of existing chassis of rail vehicles.

[0044] The present invention further relates to a rail vehicle with a running gear according to the invention. This also obviously results in the same advantages and properties as the running gear according to the invention, which is why a repeated description is omitted.

[0045] Further features, details, and advantages of the invention will become apparent from the following exemplary embodiments explained with reference to the figures. They show: Figure 1: a schematic plan view of the chassis according to the invention according to an embodiment; Figure 2: a rheological equivalent circuit diagram of an embodiment of the device according to the invention with the actuator in the first operating mode (left) and a schematic representation of the corresponding dynamic stiffnesses (right); Figure 3: a rheological equivalent circuit diagram of a conventional hydraulic bushing (left) and a schematic representation of its dynamic stiffness (right); Figure 4: the representations according to Figure 2 in case of actuator leakage; Figure 5: the representations according to Figure 3 in case of a leakage of the hydraulic bushing; Figure 6: the representations according to Figure 2 in case of a leakage of the damping device; Figure 7: the representations according to Figure 2 in case of simultaneous leakage of actuator and damping device; Figure 8: the rheological equivalent circuit diagram of the device according to the invention according to Figure 2with the actuator in the third operating mode; and Figure 9: the rheological equivalent circuit diagram of the device according to the invention according to Figure 2 with the actuator in the second operating mode.

[0046] In the Figure 1 A schematic plan view of an embodiment of the running gear 10 according to the invention is shown. The figure shows part of a car body or car 1 of the rail vehicle during cornering (the tracks are shown as curved lines). The part of the car 1 shown comprises a running gear 10 with two steerable wheel axles 12, which together form a wheelset of the running gear 10. Each wheel axle 12 comprises two wheels that are rigidly or non-rotatably connected to one another via an axle and rest on the tracks. The steering or control of the wheel axles 12 or the wheelset is carried out via an active wheelset control, which is described in more detail below.

[0047] In the embodiment shown here, each wheel axle 12 is adjustable on one side via an actuator 22, with the wheel axles 12 being coupled to the actuators 22 on different sides. Alternatively, the wheel axles 12 could be coupled to an actuator 22 on each side. The primary goal of the active wheel set control is to apply pressure to the actuators 22, causing the wheel axles 12 to rotate about their vertical axes.

[0048] In this exemplary embodiment, the actuators 22 are hydraulic actuators. These are preferably actuators described in DE 10 2017 002 926 A1. Of course, other actuators 22 can also be used for active wheel set control.

[0049] The actuators 22 are fastened on the one hand to a chassis frame 18 of the chassis 10, which is in the Figure 1is only schematically indicated by a line. The movable parts of the actuators 22 are each coupled to a swing arm 14 of a wheel suspension of the associated wheel axle 12. By actuating the actuator 22, which couples the corresponding swing arm 14 to the chassis frame 18, the respective wheel axle 12 is pivoted.

[0050] On the side opposite the actuator 22, each wheel axle 12 is also connected to the chassis frame 18 via another swing arm 14 and a bearing 19. The bearing 19 can be, for example, a mechanical bearing or a hydraulic bushing.

[0051] According to the invention, a damping device 24 or axle damper 24 (these two terms are used synonymously below) is provided parallel to each actuator 22, which also couples the swing arm 14 to the chassis frame 18. Each wheel axle 12 is thus mounted on the chassis 10 and actively adjustable via a device 20 comprising an actuator 22 and a damping device 24. At the same time, the device 20 serves to dampen the respective wheel axle 12 to ensure smooth running.

[0052] As an alternative to the embodiment shown here, two wheel axles could also be coupled via a common actuator 22, wherein the actuator can additionally be attached to the chassis 10. In this case, a damping device 24 would also be coupled to the two wheel axles in parallel to the actuator 22.

[0053] The additional damping device 24 according to the invention is characterized by the fact that it does not have a static base stiffness, but rather only a frequency-dependent, dynamic, or equivalent stiffness. The stiffness increases with the excitation frequency. In contrast to a damper with static residual stiffness, as is the case with conventional hydraulic bushings, for example, the actuator 22 does not have to work against the static residual stiffness of the damping device 24, so that less force is required to adjust the wheel axle 12.

[0054] The damping device 24 is also attached to the chassis frame 18 and coupled to the wheel axle 12 via an axle bearing cover 16, which in turn is connected to the swing arm 14. The longitudinal axis of the damping device 24 intersects the wheel axle 12, so that no additional torque is applied to the swing arm 14 via the damping device 24.

[0055] Connecting the damping device 24 via the axle bearing cover 16 facilitates the retrofitting of existing chassis 10. This eliminates the need to adjust the entire swing arm 14 during retrofitting. However, connecting the damping device 24 to the swing arm 14 without cutting the axes of the wheel axle 12 and the damping device 24 is also possible.

[0056] If position detection on the actuator 22 is required for wheelset control, a corresponding sensor, for example in the form of technically established solutions, can be integrated into the parallel damping device 24. This makes it possible to protect the displacement sensor or position sensor from the ambient conditions near the wheelset and also facilitates sensor replacement.

[0057] The damping device 24 can comprise a single damping element or a combination of different damping elements. These can either all be permanently connected in parallel with the actuator 22, or one or more damping elements can be activated or connected in the event of a fault in the actuator 22 (particularly in the event of a fluid leak).

[0058] The Figure 2 shows in the left figure a rheological equivalent circuit diagram of an embodiment of the device 20 according to the invention comprising the actuator 22 and the damping device 24 and in the right figure a schematic representation of the corresponding equivalent stiffness c eq of the actuator 22 (upper dashed line), the damping device 24 (lower dashed line) and their combination (solid line) as a function of the excitation frequency f.

[0059] In this embodiment, the actuator 22 has three operating modes: in a first operating mode, which is in the Figure 2 As shown, the actuator 22 represents a passive damping element with a frequency-dependent equivalent stiffness and a residual stiffness of zero. This first operating state or operating mode is preferably assumed when the rail vehicle is traveling straight ahead. For this purpose, the actuator 22 is set to the selected switching position via an external valve circuit of the wheelset control. In this switching state, the actuator 22 acts as a Maxwell element.

[0060] In the Figure 3 The equivalent circuit diagram of a conventional hydraulic bushing 30 is shown for comparison. As shown in the right figure of the Figure 3As can be seen, the hydraulic bushing 30 has an equivalent stiffness that increases with frequency and a residual stiffness greater than zero. The zero-point stiffness of the hydraulic bushing 30 corresponds to the static basic stiffness c 2 .

[0061] The equivalent stiffness of the device 20 according to the invention, ie the parallel arrangement of actuator 22 and damping device 24, is selected in this embodiment such that it is equivalent to the equivalent stiffness of the hydraulic bushing 30, with the exception of the stiffness at the zero point, which is zero in the device according to the invention.

[0062] If an oil leak occurs in the actuator 22 of the device 20 according to the invention, the damping effect is still provided by the parallel axle damper 24. Its equivalent stiffness provides sufficient stiffness or damping, particularly at high travel speeds, so that sinusoidal running of the wheelset is avoided.

[0063] This fault case is shown in the equivalent circuit diagram of the Figure 4shown. The equivalent stiffness curves (right-hand figure) show that the static stiffness c 2 remains for the hydraulic bushing 30 and, in the event of a leak at the actuator 22, the equivalent stiffness of the axle damper 24 remains. In the event of a leak at the actuator 22, an unstable wheelset is thus counteracted by the equivalent stiffness of the axle damper 24. Since unstable running can only occur at high speeds, i.e. at high excitation frequencies, an (equivalent) stiffness is only required at higher frequencies. A hydraulic bushing 30, on the other hand, uses its basic static stiffness c 2 in the event of a leak, due to its design, to counteract a wheelset that is becoming unstable.

[0064] Due to the parallel arrangement of actuator 22 and axle damper 24 according to the invention, the wheelset control system has the following states in the event of a leakage error: i) Leakage in actuator 22 (see Figure 2 ): The load path via the actuator 22 is eliminated. The axle damper 24 generates an equivalent stiffness through the external excitation of the wheelset, thus ensuring stable running. The value of this equivalent stiffness must at least correspond to the static stiffness of a hydraulic bushing for the relevant speed ranges. This creates a comparable situation to the currently established hydraulic bushing. ii) Leakage in the damping device 24 (see Figure 6 ): The load path via the axle damper 24 is eliminated. When the rail vehicle travels straight ahead, the actuator 22 takes over the power flow and stabilizes the wheelset. iii) Simultaneous leakage of actuator 22 and damping device 24 (see Figure 7): This case requires a double fault of two independent devices or components. The associated residual risk is now widely accepted; one example is the double design of anti-roll devices on high-speed trains.

[0065] The realization of active wheelset control via the parallel arrangement of an actuator 22 and a damping device 24 has the advantage that the actuator 22 only has to work against the damping device 24 during the positioning of the wheel axle 12. In contrast, when using a hydraulic bushing 30, the actuator would have to overcome both the damping and the basic stiffness c 2 of the hydraulic bushing 30 during positioning, which means that a significantly greater energy expenditure must be applied for the positioning of the wheelset.

[0066] The second operating mode of the actuator 22 is in the Figure 9shown. Here, the actuator can be actively adjusted, thus specifically changing the positioning of the coupled wheel axle 12. This is also done via the external valve circuit of the wheelset control. For this purpose, the actuator 22 can have an axle body firmly connected to the chassis frame 18, in which a hydraulic synchronizing cylinder is formed, which adjusts the wheel axle 12 when actuated, as described, for example, in DE 10 2017 002 926 A1.

[0067] In a third operating mode, the actuator 22 is hydraulically blocked (see Figure 8 ). This operating state can be assumed, for example, during effective traction or while holding an approached position.

[0068] The control and / or regulation of the external valve circuit is preferably carried out automatically based on sensor data. In particular, straight-ahead driving or cornering is automatically detected, and the valve circuit is controlled and / or regulated accordingly.

[0069] The damping function of the damping device 24 can alternatively be integrated directly in the actuator 22. However, due to the limited space in the actuator 22, a separate arrangement is preferred and the damping device 24 is integrated in the Figures 2 , 4 and 6-9 each shown outside the actuator 22. List of reference symbols:

[0070] 1 Wagon 10 Chassis 12 Wheel axle 14 Swing arm 16 Axle bearing cover 18 Chassis frame 19 Bearing 20 Device 22 Actuator 24 Damping device / axle damper 30 Hydraulic bushing

Claims

1. Chassis (10) of a rail vehicle, comprising an axle (12) and a device (20) for controlling the axle, wherein the device (20) comprises a fluidic actuator (22), which couples the axle (12) to the chassis (10) and by means of which the steering angle of the axle (12) can be adjusted, wherein the chassis (10) comprises a damping apparatus (24), which has frequency-dependent dynamic rigidity but does not have static rigidity and couples the axle (12) to the chassis (10) in parallel with the actuator (22), wherein, in a first operating mode, the actuator (22) constitutes a passive damping element having frequency-dependent dynamic rigidity but in particular without static rigidity and, in a second operating mode, acts as a servo drive, by means of which the steering angle of the axle (12) can be adjusted, and wherein the actuator (22) is fixed, in particular fluidically blocked, in a third operating mode.

2. Chassis (10) according to claim 1, wherein the various operating modes of the actuator (22) can be activated by means of a control valve, which in particular connects fluidic inlets and outlets of the actuator (22) to a fluid source, wherein the control valve can preferably be switched via a control unit.

3. Chassis (10) according to claim 2, wherein the control unit is configured to switch the control valve into a switch position activating the first operating mode when the rail vehicle is travelling in a straight line and / or to switch the control valve into a switch position activating the second operating mode when the rail vehicle is travelling around a bend, wherein the control unit is preferably further configured to automatically identify said rail vehicle travelling in a straight line or travelling around a bend and to accordingly switch the control valve on the basis of signals from at least one sensor.

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

5. Chassis (10) according to claim 4, wherein a damping element of the damping apparatus (24) is designed as a fluidic, in particular hydraulic, shock absorber.

6. Chassis (10) according to any of claims 4 or 5, wherein a damping element of the damping apparatus (24) is permanently switched in parallel with the actuator (22) and / or wherein a damping element of the damping apparatus (24) can be engaged when required, in particular in the event of a malfunction of the actuator (22), which can preferably be registered by detecting a drop in pressure by means of a pressure sensor provided in the actuator (22).

7. Chassis (10) according to claim 6, wherein the actuator (22) comprises a pressure sensor, by means of which a drop in pressure in the actuator (22) can be detected, wherein the engageable damping element is preferably fluidically coupled to the actuator (22) such that it is automatically engaged in the event of a drop in pressure.

8. Chassis (10) according to any of the preceding claims, wherein the damping apparatus (24) couples the axle (12) to the chassis (10) in parallel with the actuator (22) such that the rigidities of the actuator (22) and the damping apparatus (24) add together, wherein the system of the actuator (22) and the damping apparatus (24) preferably does not have static rigidity.

9. Chassis (10) according to any of the preceding claims, wherein the axle (12) is rotatably mounted on a wheel suspension, to which both the actuator (22) and the damping apparatus (24) are coupled, wherein, preferably, the actuator (22) is connected to a swing arm (14) of the wheel suspension and / or the damping apparatus (24) is connected to an axle bearing cap (16) of the wheel suspension.

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

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

12. Chassis (10) according to any of the preceding claims, wherein the actuator (22) comprises an axle body fastened to the chassis (10), a fluidic synchronised cylinder and a housing which is movable relative to the axle body in accordance with a movement of the synchronised cylinder and is coupled to the axle, wherein the synchronised cylinder is preferably formed in the axle body and comprises a piston, which comprises a piston rod which penetrates the axle body on each of its two flat sides and is in particular connected to the housing via a piston spring element at its end remote from the piston surface.

13. Device (20) for controlling an axle (12) of a chassis (10) according to any of the preceding claims, comprising a fluidic actuator (22), which can be coupled both to the axle (12) and to the chassis (10) and by means of which the steering angle of the axle (12) can be adjusted, wherein the device (20) comprises a damping apparatus (24), which has frequency-dependent dynamic rigidity but does not have static rigidity and can be coupled both to the axle (22) and to the chassis (10) in parallel with the actuator (12), wherein, in a first operating mode, the actuator (22) constitutes a passive damping element having frequency-dependent dynamic rigidity but in particular without static rigidity and, in a second operating mode, acts as a servo drive, by means of which the steering angle of the axle (12) can be adjusted, and wherein the actuator (22) is fixed, in particular fluidically blocked, in a third operating mode.

14. Rail vehicle comprising a chassis (10) according to any of claims 1 to 12.

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