Suspension device for a rail vehicle

Abstract

The invention relates to a suspension device (1) for a rail vehicle, the suspension device being designed to be provided between a car body (2) and a bogie frame (3), comprising at least one air spring (4) and an emergency spring (5) in series with the air spring (4), wherein a compression device (6) is provided which is acted upon by a fluid pressure (8), the fluid pressure being proportional to the pressure (7) in the air spring (4), and compresses the emergency spring (5) as a function of the fluid pressure (8).

Description

[0001] 202418427

[0002] 1

[0003] Description

[0004] Suspension system for a rail vehicle

[0005] Technical field

[0006] The invention relates to a suspension device for a rail vehicle for cushioning a car body against a chassis.

[0007] State of the art

[0008] The bogies of rail vehicles, especially passenger rail vehicles, are equipped with suspension systems to ensure modern ride comfort. A common type of suspension uses air springs, in which the car body rests on the bogie via bellows filled with pressurized gas, which are generally cylindrical or barrel-shaped. These bogies, often designed as two-axle bogies, themselves have a suspension system that cushions the axles, axle bearings, brake components, etc., relative to the bogie, thus reducing unsprung mass. This primary suspension reduces wear on the rails and the bogie by minimizing the impact forces acting on these components. Coil, leaf, or rubber spring elements are typically used as spring elements in a primary suspension system. A particular advantage of air suspension as a secondary, or secondary, spring system is its ability to reduce the impact forces acting on these components.Secondary suspension relies on the ability to adjust the height of the car body above the rail level by varying the gas pressure in the air springs. This is particularly advantageous for subway vehicles, as stepless boarding is essential for quick and safe passenger exchange, even under all permissible load conditions. In the event of a malfunction, such as a leak in the air springs or a failure of the compressed gas supply, the vehicle's continued safe operation is ensured because the car body lowers onto an emergency spring. However, ride comfort is reduced, and the leveling function of the secondary suspension is no longer available. Furthermore, this creates the risk of the platform colliding with an open vehicle door, which, in the worst-case scenario, could prevent the doors of a loaded vehicle from opening if the air suspension fails.Since, during such an emergency spring run, the equipment located below the car body also comes closer to the track bed, 202418427.

[0009] 2. The design must also take this into account, so that these underfloor devices must be made correspondingly smaller. Since the opening of the doors on a platform must be ensured under all circumstances, sometimes elaborate door designs are accepted, in which these have flaps that swing out upon collision with a platform and allow the doors to open. This solution is unsatisfactory both structurally and aesthetically.

[0010] Description of the invention

[0011] The invention is therefore based on the objective of providing a suspension device for a rail vehicle which, even in the event of failure of an air suspension device, allows the car body to be guided at the same height above the top of the rail as with a correctly functioning air suspension device.

[0012] The problem is solved by a suspension device for a rail vehicle having the features of claim 1 and a rail vehicle according to claim 6. Advantageous embodiments are the subject of dependent claims.

[0013] The basic idea of ​​the invention describes a suspension device for a rail vehicle, which is designed for arrangement between a car body and a bogie frame and which comprises at least one air spring and an emergency spring arranged in series with the air spring, wherein a compression device is provided which is subjected to a pressure of a fluid proportional to the pressure in the air spring and which compresses the emergency spring depending on this pressure of a fluid.

[0014] This offers the advantage of preventing the car body, which is supported by the air spring, from sagging in the event of a malfunction in the air suspension system. A malfunction is defined as a loss of pressure in the air spring, caused by the failure of one of the components of the air suspension system (air spring, piping, compressed air source, control valves, etc.). In such a case, with conventional air suspension systems, the car body sags until it is held by a stop inside the air spring. While this allows the vehicle to continue driving, it does so with the aforementioned limitations and potential hazards. 202418427

[0015] 3

[0016] According to the invention, an emergency spring is provided in series with the air spring and is compressed by means of a compression device during normal operation, i.e., when the air spring system is functioning. This emergency spring and the compression device are designed such that if the air spring or a component of the air spring system fails, the pressure in the compression device also drops, causing the emergency spring to relax.

[0017] Since the emergency spring and the air spring are connected in series, the relaxing emergency spring lifts the air spring and thus also the car body. This allows the height of the car body above the top of the rail to be maintained at the target level, even though the car body rests on the stop in the air spring. The target level is considered to be the preferred level for the vehicle and the stations; usually, it is the level that allows passengers step-free boarding and alighting, i.e., that the vehicle floor is level with the platform level.

[0018] According to the invention, a compression device is provided which is arranged in such a way that it is capable of compressing the emergency spring. Since the emergency spring rests with one end on a bogie, in particular a bogie frame, it is advantageous to equip the bogie with a recess to which the compression device can be attached at one end and which allows force to be introduced into the compression device. The other end of the compression device is to be connected to the end of the emergency spring facing away from the bogie in such a way that forces can be transmitted between the compression device and the emergency spring.

[0019] The compression device is preferably designed as a pneumatic or hydraulic cylinder and pressurized with a fluid whose pressure is proportional to the pressure in the air spring. This pressure can be identical to the pressure in the air spring; however, it is advantageous to design the compression device to operate at a higher fluid pressure than the air spring.

[0020] This preferred embodiment provides for the use of a pressure intensifier, which converts the pressure in the air spring into an equivalent, but higher, fluid pressure for the compression device. The air spring pressure, which is usually in the form of compressed air, can also be converted into the pressure of a liquid as the fluid pressure for the compression device.

[0021] This is particularly advantageous because the compression device should preferably be designed with the smallest possible dimensions, and higher pressures allow for a smaller piston diameter in the compression device. 202418427

[0022] 4

[0023] The emergency spring is preferably designed as an elastic element with a spring characteristic that is so stiff as to minimize the sagging of the car body due to the vehicle's load and the resulting compression of the emergency spring, while simultaneously meeting the safety requirements regarding derailment caused by a wheel climbing. Such a stiff emergency spring therefore also requires increased forces to compress it during normal operation, i.e., when the air spring is functioning, to compress the so-called air spring gap.

[0024] The air spring gap is the distance that exists between the stop in the air spring and its corresponding counterpart, against which the stop rests when the air spring is depressurized, when the air spring is in its normal position. This normal position corresponds to the position that is designed as such, in particular the one that results in a platform-level floor.

[0025] In a further development of the invention, it is advantageous to design the compression device as a double-acting unit. This allows both a compressive force and a tensile force to be exerted on the emergency spring. The compression device is thus designed as a double-acting pneumatic or hydraulic cylinder and requires control valves and regulating devices. In this way, compensation of the primary spring can also be achieved by appropriately determining the current deflection of the rail vehicle. This primary spring, generally designed as a steel spring, is not affected by the determination of the air spring deflection using an air spring valve, so that under heavy load conditions a certain, uncompensable deflection and therefore a level difference between the floor and the platform remains. However, this level difference can also be compensated for by means of a double-acting compression device.

[0026] In a further development of the invention, it is advantageous to limit the preload of the emergency spring by increasing the vehicle's load. For this purpose, a pressure reducing valve is installed in the supply line from the pressure in the air spring to the pressure converter, so that the fluid pressure in the compression device is limited to a maximum, predefinable value.

[0027] An advantageous embodiment of the invention, building upon the preceding exemplary embodiment, provides for a load-dependent reduction of the preload of the emergency spring, in addition to limiting the fluid pressure in the compression device. For this purpose, a so-called differential pressure-pressure converter is used, which transfers a fluid pressure generated by a pressure difference to the fluid chamber of the 202418427

[0028] 5

[0029] This leads to a compression device. This pressure differential is generated from the pressure in the air spring, which is further limited by a pressure reducing valve, and the pressure in the air spring, which is routed through a pressure switching valve. The pressure switching valve is configured to open at a specific pressure in the air spring and supply this pressure to the differential pressure pressure converter. In this way, from a certain pressure in the air spring, the fluid pressure in the compression device is reduced and the preload of the emergency spring is reduced. This can also compensate for the compression of the primary suspension, provided that the individual components, in particular the switching pressures of the valves and the transmission ratio of the differential pressure pressure converter, as well as its differential calculation, are adapted to the specific application.However, conventional air spring valves generally fail in this application, as the configuration shown here, in conjunction with a conventional air spring valve, tends to cause oscillations in the level control system. Therefore, an electronic air spring valve must be used.

[0030] Another preferred embodiment of the invention provides to increase the fluid pressure acting on the compression device only up to a certain pressure in the air spring proportionally to this pressure, and to reduce the fluid pressure proportionally to the pressure in the air spring if the pressure in the air spring continues to increase.

[0031] To convert the pressure in the air spring, a differential pressure-to-pressure converter is required, which determines the fluid pressure based on a pressure difference. The air spring pressure is fed to a 3 / 2-way valve, which is configured so that the fluid pressure is increased proportionally to the pressure in the air spring up to a specific switching pressure, and then reduced proportionally to the pressure in the air spring above this switching pressure. Such a pressure-controlled, adjustable 3 / 2-way valve offers two switching positions. Up to a specific switching pressure, the supplied pressure is directed to a first output of the 3 / 2-way valve; above this switching pressure, the first output is closed, and the supplied pressure is directed to a second output of the 3 / 2-way valve.These outputs are connected to the differential pressure-pressure converter in such a way that the first output is fed to the pressure chamber of the differential pressure-pressure converter, which increases the fluid pressure, and the second output is fed to the pressure chamber of the differential pressure-pressure converter, which reduces the fluid pressure, in each case with increasing air spring pressure.

[0032] A particularly advantageous embodiment of the invention provides for replacing the 3 / 2-way valve with a 4 / 2-way valve, thus ensuring better venting of the pressure chambers of the differential pressure converter. 202418427

[0033] 6

[0034] The invention further comprises a rail vehicle with a car body and at least one chassis with a bogie frame, which is equipped with one of the above-described embodiments of a suspension device.

[0035] Brief description of the drawings

[0036] They show, for example:

[0037] Fig. 1 Suspension device - schematic representation, normal operation.

[0038] Fig. 2 Suspension device - schematic representation, emergency spring operation.

[0039] Fig. 3 Suspension device normal operation.

[0040] Fig. 4 Suspension device emergency spring operation.

[0041] Fig. 5 Suspension device normal operation, with pressure reducing valve.

[0042] Fig. 6 Suspension device normal operation, with load-dependent reduction of the preload of the emergency spring.

[0043] Fig. 7 Suspension device with 3 / 2 way valve for controlling the differential pressure pressure converter

[0044] Fig. 8 Suspension device with 4 / 2 way valve for controlling the differential pressure pressure converter

[0045] Implementation of the invention

[0046] Fig. 1 shows an exemplary and schematic representation of a suspension device in a highly abstracted principle diagram during normal operation. A suspension device 1 for suspending a car body 2 relative to a bogie frame 3 is shown, comprising an air spring 4 on which the car body 2 rests. An emergency spring 5 is arranged in series with the air spring 4 below it. This emergency spring 5 transmits the compressive forces introduced into it by the air spring 4 to the bogie frame 3. The air spring 4 includes a stop 9, which is located inside the air spring 4 and which, in the event of a loss of gas pressure in the air spring 4, prevents the air spring from being completely deformed, but rather holds the car body 2 via the stop 9. A plate 10 is located between the 202418427

[0047] 7

[0048] Air spring 4 and emergency spring 5 are provided. An air spring gap 14 exists between the stop 9 and the plate during normal operation. In the normal operating mode shown, the car body 2 is in its target position above the bogie frame, ensuring level boarding for passengers when the train stops at a platform. The distance 12 between the air spring 4 mounting point on the car body 2 and the plate 10 is at its target value. The distance 11 between the car body 2 and the bogie frame 3 is also at its target value. If the vehicle's load increases, the air spring 4 is compressed, and the distance 12, and consequently the distance 11, decrease. This is detected by a level control system, which increases the pressure 7 in the air spring 4 so that the distance 11 returns to its target value. The reverse process occurs when the load is reduced.The necessary components, such as control valves and linkages, are known and are not shown in Fig. 1 for the sake of simplicity. The suspension device 1 is designed such that, in the event of a loss of pressure 7 in the air spring, it maintains the distance 11 between the car body 2 and the bogie frame 3. For this purpose, the emergency spring 5 is pre-tensioned during normal operation so that it is compressed by at least the amount of the air spring gap 14 and only relaxes when the pressure 7 in the air spring is lost, thereby bringing the car body to its target level, at which the distance 11 assumes its target value. This pre-tension is achieved by means of the compression device 6, which is designed to apply a compressive force to the plate 10 and thus to the emergency spring 5.The compression device 6 is supported by a projection 15 on the bogie frame 3. In the schematic diagram shown, the compression device 6 is depicted as a pneumatic cylinder pressurized by the pressure 7 in the air spring 4. In practical implementations of the invention, the forces required to compress the emergency spring 5 necessitate a calculation of the required pressure, making the use of a pressure converter advantageous.

[0049] Fig. 2 shows an exemplary and schematic representation of a suspension device in a highly abstracted principle diagram during emergency spring operation. The suspension device 1 from Fig. 1 is shown, with the air spring 4 depressurized, for example, due to defective piping or damage to the air spring itself. In this state, the air spring 4 no longer has any effect; the car body 2 rests against the plate 10 via the stop 9, thus reducing the distance 12. The distance 12 is reduced by the value of the air spring gap 14 in normal operation. In the emergency spring operation shown in Fig. 2, there is no air spring gap 14; it assumes a value of zero. Simultaneously with the release of pressure 7 from the air spring 4, the pressure in the compression device 6 also escapes, so that it can no longer maintain the preload of the emergency spring 5. The emergency spring 5 relaxes.

[0050] 8 therefore raises the car body 2 to its target level, i.e. the distance 11 between the car body 2 and the bogie frame 3 is the same as during normal operation.

[0051] Fig. 3 shows an exemplary and schematic representation of a suspension device in normal operation. A suspension device 1 is depicted, comprising essential elements for practical application. An air spring 4 with a stop 9 located inside the air spring 4 is arranged above an emergency spring 5, which in turn rests on a bogie frame 3. The compression device is designed such that a projection 15 of the bogie frame forms a cylinder in which the plate 10, designed as a piston, is guided. The plate 10 is arranged between the air spring 4 and the emergency spring 5, as shown in the schematic diagrams of Figs. 1 and 2. A fluid chamber 17, extending in an annular shape around the emergency spring 5, exists between the projection 15 and the plate 10.This solution offers a significantly larger effective piston cross-section than would be achievable in the typical installation situation for an air suspension with conventional cylinders, and therefore reduces the required fluid pressure. The illustrated embodiment also includes a section of the emergency spring 5 between the plate 10 and the air spring 4, which cannot be compressed by the compression device. Fig. 3 shows normal operation, in which the air spring gap 14 assumes a specific setpoint. The emergency spring 5 is accordingly compressed by the same amount. Furthermore, a pressure converter 16 is provided, to which the pressure 7 prevailing in the air spring 4 is supplied. This pressure converter 16 transforms this pressure 7 into a higher fluid pressure 8, which is linearly proportional to the pressure 7. This can be achieved, for example, as shown in Fig.Figure 3 shows that the adjustment is achieved by means of two mechanically connected cylinders which have a common piston rod but pistons of different sizes. The fluid pressure 8 can be in a gaseous or liquid medium. Due to the higher pressure value of the fluid pressure 8 compared to the pressure 7 in the air spring 4, a design as a hydraulic cylinder is advantageous. In particular, it is advantageous that a hydraulic system consisting of pressure converter 16, fluid chamber 17, and the associated piping is significantly less prone to vibrations than a pneumatic system. The level control by varying the pressure 7 in the air spring 4 can therefore operate without interference.

[0052] Fig. 4 shows an exemplary and schematic representation of a suspension device in emergency spring operation. The suspension device 1 from Fig. 3 is depicted in the event of a loss of pressure 7 in the air spring 4. The car body (not shown in Figs. 3 and 4) rests on the emergency spring 5 via the stop 9, and the air spring gap 14 is zero. Due to the release of pressure 7 from the pressure converter 16, the fluid pressure 8 also drops, so that 202418427

[0053] 9 The emergency spring 5 relaxes and lifts the car body above the stop 9 to its target level. The compression of the emergency spring 5, as well as the air spring gap 14, is zero. The fluid chamber 17 is reduced to its geometrically smallest possible volume.

[0054] Fig. 5 shows an exemplary and schematic representation of a suspension device in normal operation with a pressure reducing valve. It is a suspension device 1, similar to those shown in Figs. 3 and 4, except that the pressure converter 16 is supplied via a pressure reducing valve 18 from the pressure 7 in the air spring 4. The suspension device 1 is shown in normal operation, i.e., with a sealed air spring 4 and a functioning compressed air supply. The pressure reducing valve 18 limits the pressure supplied to the pressure converter 16 from the pressure 7, so that this supplied pressure cannot exceed a certain value. This also limits the force exerted on the plate 10 from the fluid chamber 17. Thus, the preload of the emergency spring 5 caused by the pressure 7 in the air spring 4 is limited to a certain value. This prevents excessive deflection of the car body 2 relative to a bogie frame 3.

[0055] Fig. 6 shows, by way of example and schematically, a suspension device with load-dependent reduction of the preload of the emergency spring in normal operation. A suspension device 1, as disclosed in Fig. 5, is shown, with the exception that a differential pressure-pressure converter 20 is provided to translate the pressure 7 in the air spring 4 into the fluid pressure 8. Such a differential pressure-pressure converter 20 has a cylinder with a piston, the piston being subjected to a specific pressure on each side. In this way, the piston is driven by the difference of these pressures, and the driving force on the piston caused by the pressure 7 can be reduced by applying a further pressure to the opposite side of the piston, consequently reducing the fluid pressure 8 accordingly. In the illustrated embodiment, the pressure 7 in the air spring (as also shown in Fig. 5) is...5) via a pressure reducing valve 18 to one side of the piston of the differential pressure pressure converter 20. Pressure is supplied to the opposite side, which reduces the driving force on the piston. This pressure is generated by the pressure 7 in the air spring 4, which is routed via a pressure switching valve 19. This pressure switching valve 18 opens at a specific, predetermined pressure 7 in the air spring 4 and supplies this pressure to the side of the cylinder that reduces the driving force on the piston. This reduces the fluid pressure 8 and thus the preload of the emergency spring 5, resulting in a load-dependent reduction of the preload of the emergency spring 5. This can be used, in particular, to also compress the primary suspension of the vehicle.

[0056] 10 compensate. A further advantage of such a device is that it provides a possibility for stepless adaptive stiffness control of the air spring 4 while maintaining a constant floor level. However, it is necessary to use an electronic air spring valve 21 instead of a conventional air spring valve controlled by a linkage, since the latter can tend to cause oscillations in the level control.

[0057] Fig. 7 shows an exemplary and schematic representation of a suspension device with a 3 / 2-way valve for controlling the differential pressure converter. The suspension device 1 is constructed like the one in Fig. 5, with a 3 / 2-way valve 22 provided for controlling the differential pressure converter 20. This 3 / 2-way valve 22 is pressure-controlled and its switching pressures are adjustable. It vents the pressure chamber of the differential pressure converter 20 that increases the fluid pressure 8 up to a specific, predefinable switching pressure. Above this switching pressure, no further pressure increase is supplied to the aforementioned pressure chamber of the differential pressure converter 20. At the same switching pressure, a valve integrated into the 3 / 2-way valve 22 opens and supplies the air spring pressure 7 to the pressure chamber that reduces the fluid pressure 8. In this way, the fluid pressure 8 is reduced again from this pressure, and the force acting on the emergency spring 5 is also reduced.

[0058] Fig. 8 shows an exemplary and schematic representation of a suspension device with a 4 / 2-way valve for controlling the differential pressure converter. It depicts an improved embodiment of the suspension device 1, as disclosed in Fig. 7. Here, a 4 / 2-way valve 23 is provided instead of a 3 / 2-way valve. Such a 4 / 2-way valve 23 offers the advantage of improved venting of the pressure chamber of the differential pressure converter 20, which reduces the fluid pressure 8.

[0059] 202418427

[0060] 11

[0061] Reference symbol list

[0062] 1 Suspension device

[0063] 2 car bodies

[0064] 3 bogie frames

[0065] 4 air springs

[0066] 5 emergency spring

[0067] 6 Compression device

[0068] 7 Pressure in the air spring

[0069] 8 Fluid pressure

[0070] 9 attacks

[0071] 10 plates

[0072] 11 Distance between car body and bogie frame

[0073] 12 Distance between car body and plate

[0074] 13 Distance plate - bogie frame

[0075] 14 Air spring gap

[0076] 15 Formation

[0077] 16 pressure converters

[0078] 17 Fluid space

[0079] 18 Pressure reducing valve

[0080] 19 Pressure switching valve

[0081] 20 Differential pressure pressure converters

[0082] 21 Electronic air spring valve

[0083] 22 Pressure-controlled 3 / 2-way valve, adjustable

[0084] 23 Pressure-controlled 4 / 2-way valve, adjustable

Claims

202418427 12 Patent claims 1. Suspension device (1) for a rail vehicle, designed for arrangement between a car body (2) and a bogie frame (3), comprising at least one air spring (4) and an emergency spring (5) arranged in series with the air spring (4), characterized in that a compression device (6) is provided which is subjected to a pressure (8) of a fluid proportional to the pressure (7) in the air spring (4) and which compresses the emergency spring (5) depending on this pressure (8) of a fluid.

2. Suspension device (1) for a rail vehicle according to claim 1 , characterized in that the pressure (8) acting on the compression device (6) is derived from the pressure (7) in the air spring (4) by means of a pressure converter (16).

3. Suspension device (1) for a rail vehicle according to claim 1 or 2, characterized in that the compression device (6) is designed as a pneumatic cylinder.

4. Suspension device (1) for a rail vehicle according to claim 1 or 2, characterized in that the compression device (6) is designed as a hydraulic cylinder.

5. Suspension device (1) for a rail vehicle according to one of claims 1 to 4, characterized in that the pressure converter (16) is configured to convert the pressure (7) in the air spring (4) into a pressure (8) of a liquid.

6. Suspension device (1) for a rail vehicle according to one of claims 1 to 5, characterized in that the pressure supplied to the pressure converter (16) is formed from the pressure (7) in the air spring (4) by means of a pressure reducing valve (18).

7. Suspension device (1) for a rail vehicle according to claim 6, characterized in that 202418427 13 a differential pressure-pressure converter (20) is provided for the conversion of the pressure (7) in the air spring (4), which determines the fluid pressure (8) depending on a difference between a pressure (7) in the air spring (4), which is limited by means of a pressure reducing valve (18), and a pressure which is formed from the pressure (7) in the air spring (4) passed through a pressure switching valve (19).

8. Suspension device (1) for a rail vehicle according to one of claims 1 to 5, characterized in that a differential pressure converter (20) is provided for converting the pressure (7) in the air spring (4), which determines the fluid pressure (8) as a function of a pressure difference (4), wherein the pressure (7) is supplied to a 3 / 2-way valve (22), which is switched such that the fluid pressure (8) is increased proportionally to the pressure (7) in the air spring (4) up to a certain switching pressure and from this switching pressure the fluid pressure (8) is reduced proportionally to the pressure (7) in the air spring (4).

9. Rail vehicle with a car body (2) and at least one chassis, comprising a bogie frame (3), characterized in that at least one suspension device (1) according to one of claims 1 to 8 is arranged between the car body (2) and the bogie frame (3).

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