Title:
BRAKE SYSTEM HAVING SMART ACTUATOR FOR BRAKING A RAIL-GUIDED VEHICLE
Kind Code:
A1


Abstract:
A brake system for braking a rail vehicle has an actuator, which is equipped for installation in its totality in a bogie of the rail vehicle and provided with a braking force F so as to create a braking movement of at least one pressing part, and an energy storage device which is connected to the actuator via a supply line. A brake controller supplies control signals for controlling the brake system, which enables secure braking of the rail vehicle. The actuator has a control connection, which is connected to the brake controller for receiving the control signals via a data line, wherein the control connection is connected to a logic unit of the actuator that is configured to set the braking force F in dependence on the control signals.



Inventors:
Schiffers, Toni (Erkelenz, DE)
Wiesand, Manfred (Burgthann, DE)
Application Number:
13/497858
Publication Date:
08/02/2012
Filing Date:
08/23/2010
Assignee:
SIEMENS AG (MUNICH, DE)
Primary Class:
Other Classes:
188/153R, 188/158, 701/19
International Classes:
B61H13/00; B61D17/00; F16D65/18
View Patent Images:



Foreign References:
WO2008134860A12008-11-13
Primary Examiner:
LANE, NICHOLAS J
Attorney, Agent or Firm:
LERNER GREENBERG STEMER LLP (HOLLYWOOD, FL, US)
Claims:
1. 1-20. (canceled)

21. An actuator for a brake system of a rail vehicle, the actuator comprising: means for generating a braking force for at least one pressing part receiving the braking force; a supply connection for connecting the actuator to an energy storage unit, wherein the actuator is configured in its entirety for mounting in a bogie of the rail vehicle; a control connection for connecting to a data line; and a logic unit connected to said control connection and configured to set the braking force in dependence on a control signal transferred over the data line.

22. The actuator according to claim 21, further comprising a braking force detection unit for detecting a measured variable from which a generated braking force can be derived as an actual value, said braking force detection unit is connected to said logic unit.

23. The actuator according to claim 21, wherein said supply connection is an electrical supply connection which can be connected to an electrical energy supply line and has output terminals at which a supply voltage drops when the actuator operates.

24. The actuator according to claim 23, wherein said means for generating the braking force has an electromechanical force unit connected to said supply connection and configured to generate a mechanical triggering force in dependence on electrical energy which is made available via said supply connection.

25. The actuator according to claim 24, wherein said electromechanical force unit is selected from the group consisting of an electric motor, an electric pump and a piezoelement.

26. The actuator according to claim 21, wherein said means for generating the braking force is self-energizing.

27. The actuator according to claim 21, further comprising: an electrically drivable emergency triggering means for releasing a brake; and connecting means, electrically connected to said emergency triggering means, for connecting to an external electrical energy supply.

28. A brake system for braking a rail vehicle, the brake system comprising: at least one pressing part; an actuator configured for mounting in a bogie of the rail vehicle and configured to generate a braking movement of said at least one pressing part with a braking force; an electric supply line; an energy store connected to said actuator via said electric supply line; a brake controller for making available control signals and performing open-loop or closed-loop control of the brake system; a data line; and said actuator having a logic unit and a control connection connected to said brake controller via said data line for receiving the control signals, said control connection connected to said logic unit configured to set the braking force in dependence on the control signals, said actuator having means for generating the braking movement for at least one pressing part with the braking force, said actuator further having a supply connection for connecting said actuator to said energy storage unit, wherein said actuator is configured in its entirety for mounting in the bogie of the rail vehicle.

29. The brake system according to claim 28, wherein said energy store is an electrical energy store making available an electrical supply voltage on an output side.

30. The brake system according to claim 28, further comprising a converter unit connected to said brake controller and said actuator, said converter unit having at least one converter which makes available an electrical variable on an output side in dependence on a signal for a load state which is fed in on an input side, wherein said converter is configured for connection to at least one of a pneumatic air spring of the rail vehicle or at least one pneumatic line of the rail vehicle.

31. The brake system according to claim 30, wherein said converter unit is connected to said energy store via said electrical supply line.

32. The brake system according to claim 28, wherein said data line is a data bus which connects said brake controller, said actuator and said converter unit to one another.

33. The brake system according to claim 28, further comprising an electrical safety loop, said actuator is one of a plurality of actuators connected to one another via said electrical safety loop configured to transmit control signals.

34. The brake system according to claim 28, further comprising means for detecting at least one of a load state or a mass of the rail vehicle and connected to said actuator, said actuator limits, in dependence on the load state or the mass, the braking force to be set.

35. A rail vehicle, comprising: a plurality of cars coupled to one another to form a vehicle train, each of said cars having at least one bogie; a brake system containing: at least one pressing part; an actuator configured for mounting in said bogie of the rail vehicle and configured to generate a braking movement of said at least one pressing part with a braking force; an electric supply line; an energy store connected to said actuator via said electric supply line; a brake controller for making available control signals and performing open-loop or closed-loop control of said brake system; a data line; said actuator having a logic unit and a control connection connected to said brake controller via said data line for receiving the control signals, said control connection connected to said logic unit configured to set the braking force in dependence on the control signals, said actuator further having means for generating the braking force for said at least one pressing part and a supply connection for connecting said actuator to said energy storage unit.

36. The rail vehicle according to claim 35, wherein said brake system is one of a plurality of brake systems, each of said cars has at least one of said brake systems.

37. The rail vehicle according to claim 36, further comprising a vehicle data line, said brake systems are connected to one another via said vehicle data line.

38. The rail vehicle according to claim 37, wherein each said brake controller is connected to said vehicle data line via a vehicle bus interface.

39. The rail vehicle according to claim 35, further comprising an electrical safety loop extending through all said cars, wherein each said actuator is connected to said electrical safety loop.

40. The rail vehicle according to claim 36, wherein each of said brake systems has a converter unit connected to said brake controller; and further comprising a main air line extending through all of said cars and conducting a pneumatic control pressure, said converter unit of each of said brake systems is connected to said main air line.

Description:

The invention relates to an actuator for a brake system of a rail vehicle having means for generating a braking movement of at least one pressing part with a braking force F and with a supply connection for connecting the actuator to an energy storage unit, wherein the actuator is configured in its entirety for mounting in a bogie of the rail vehicle.

The invention also relates to a brake system for braking a rail vehicle having an actuator which is configured in its entirety for mounting in a bogie of the rail vehicle and which is configured to generate a braking movement of at least one pressing part with a braking force F, an energy store which is connected to the actuator via a supply line and a brake controller which makes available control signals and has the purpose of performing open-loop or closed-loop control of the brake system.

The invention also relates to a rail vehicle having a plurality of cars which are coupled to one another to form a vehicle train, wherein each car has at least one bogie and at least one air spring.

Pneumatic brake systems for rail vehicles are known from the prior art. Pneumatic brake systems usually have a car-side brake controller which accesses control valves which can be actuated electrically. On the car side, a compressor is provided which compresses atmospheric air to acquire compressed air, and the compressed air is made available in a compressed air store. The compressed air store can therefore also be referred to as an energy store. The energy store is usually connected to an actuator via pipe connections and/or hose connections, wherein the control valves which can be actuated are arranged in the pneumatic connecting line between the energy store and the actuator. An actuator generally has a brake cylinder and brake calipers or brake activation units (for example block brake unit). The brake calipers or brake activation units are each provided with a pressing part, such as for example a brake lining, which lies opposite a brake disk which rotates during travel of the rail vehicle. A brake piston is movably arranged in the brake cylinder, wherein the brake piston, together with the brake cylinder, bounds a brake chamber in a seal-forming fashion, to which brake chamber pressure can be applied by the energy store. The pressure which is generated in the brake chamber is set by the brake controller using the control valves which can be actuated. A change in pressure brings about a movement of the brake piston in the brake cylinder with a braking force which is applied to the pressing part via an expedient lever mechanism. Frictional engagement occurs between the pressing part and the brake disk. Electropneumatic brake systems are voluminous and contribute with their high own weight to a high energy consumption of the rail vehicles.

DE 10 2006 044 022 A1 discloses a self-energizing hydraulic brake. Furthermore, self-energizing electromechanical brakes in the form of wedge brakes have been disclosed in the prior art.

The object of the invention is to make available an actuator, a brake system and a rail vehicle of the type mentioned at the beginning which permit secure braking of the rail vehicle.

The invention achieves this object on the basis of the actuator mentioned at the beginning by means of a control connection for connecting a data line and by means of a logic unit which is connected to the control connection and which is configured to set the braking force as a function of a control signal which is transferred over the data line.

Taking the brake system specified at the beginning as a basis, the invention achieves the object in that the actuator has a control connection which is connected to the brake controller via a data line in order to receive the control signals, wherein the control connection is connected to a logic unit of the actuator which is configured to set the braking force as a function of the control signals.

Taking the rail system specified at the beginning as a basis, the invention achieves the object by means of a rail vehicle having a brake system according to the invention and/or an actuator according to the invention.

According to the invention, a “smart” actuator is made available, wherein the smart actuator has a logic unit which assists in setting the braking force. For this purpose, the smart actuator receives, via its control connection, a control signal such as, for example, a setpoint value. The control signal is, for example, processed and subsequently transmitted to the logic unit. The logic unit performs the setting of the braking force as a function of said control signal. In this context, the intelligent actuator is arranged with all its components in the bogie of the rail vehicle. Since the car-side brake controller has to be connected to the actuators arranged outside of the car, exclusively for the purpose of transmitting one or more control signals, a simple data line, bus and/or wire connection is sufficient between these components. Complex pneumatic, hydraulic or mechanical connections between the car-side controller and the actuators of the bogies are avoided according to the invention. This simplifies the configuration, the installation and the costs of a brake system according to the invention.

Each actuator according to the invention expediently has a braking force detection unit for detecting a measured variable from which the generated instantaneous braking force F can be derived as an actual value, wherein said braking force detection unit is connected to the logic unit. The configuration of the braking force detection unit is self-evidently dependent on the means for generating a braking force of the actuator. These means can basically be configured in any desired way according to the invention and can be embodied, for example, in an electropneumatic, electrohydraulic or electromechanical fashion. Depending on the configuration of said means, the braking force detection unit detects a measured value, for example a hydraulic pressure or a current which is generated by the actuator or else a movement or deformation of a part of a transmitting lever mechanism, wherein a braking force is derived on the basis of the measured value. The measured value is transferred, for example, to the logic unit which sets the braking force on the basis of the control signal which is also transmitted, in such a way that the detected actual value corresponds as precisely as possible to a setpoint value predefined by a superordinate controller. In other words, the smart actuator makes available according to the invention a setpoint/actual value control process, wherein according to the invention the setpoint value is made available to the smart actuator by the superordinate brake controller.

The setpoint/actual value control process also remains active during emergency braking or rapid braking. Since the setpoint/actual value control process is carried out by the actuator itself, this control remains active even in the event of a failure or fault of the data lines or buses of the rail vehicle. As is also explained in more detail below, the setpoint value is predefined as a function of the payload of the rail vehicle. For this purpose, the state of a supporting spring, for example the pressure in an air spring, on which the car body of the respective cars is supported, is expediently detected with an expedient sensor. Braking therefore always takes place in a load-corrected fashion. This also applies to a rapid braking operation or emergency braking operation. If the data line is fault free, the braking also occurs with anti-skidding protection. This even applies to emergency braking operations.

According to one preferred refinement of the invention, the supply connection is an electrical supply connection which can be connected to an electrical energy supply line and has output terminals at which a supply voltage drops when the actuator operates. According to this advantageous refinement, the energy store is connected to the actuators arranged in the bogie via an electrical conductor. The connection between the car-side components and the brake system components of the bogie is therefore made exclusively by means of optical and/or electrical lines. The complex hydraulic or pneumatic connections between the bogie components and the components of the brake system arranged in the car of the rail vehicle are therefore eliminated.

The data line for transmitting the control signals is expediently an electrical data line. Of course, a connection via optical waveguides is also possible within the scope of the invention.

If the energy store is an electrical energy store and is connected to the supply connection via an electric line, a supply voltage drops at the output terminals of the supply connection. This supply voltage is used, for example, to generate the braking force or to initialize the build-up of braking force. The control process which is necessary here for controlling or setting the braking force is performed, as has already been stated, by the logic unit of the actuator. Electrical energy stores are, for example, batteries, accumulators, supercaps, capacitors, fuel cells or the like.

The means for generating the braking force advantageously have an electromechanical force unit which is connected to the supply connection and is configured to generate a mechanical triggering force as a function of electrical energy which is made available via the supply connection. According to this advantageous development, an electromechanical force unit is provided which makes available only a triggering force which is the cause of the further braking operation. The triggering force brings about original frictional engagement between the pressing part and a moving mass which is to be braked. This original frictional engagement leads, for example in the case of self-energizing brakes, to boosting of the braking force without additional energy having to be introduced into the brake system from the outside.

The electromechanical force unit is expediently an electric motor, an electric pump or a piezoelement. The electro-mechanical force unit interacts, for example, with a force store such as, for example, a spring to be tensioned, a hydraulic accumulator or hydraulic cylinder. The force stores are loaded by the force unit by, for example, the spring being tensioned.

The means for generating a braking movement are expediently self-energizing. As has already been stated further above, the electromechanical force unit serves in this case only to make available a low triggering force which initiates a braking process. Owing to the self-energizing effect of the electromechanical force unit, a strongly increasing braking force occurs, wherein the increasing braking force is subject to the control by the logic unit. Such self-energizing means for generating a braking force are, for example, a self-energizing hydraulic brake, which is already known from the prior art, or else also a self-energizing electromechanical brake, which can also be referred to as a wedge brake. The wedge brake is also already known to a person skilled in the art. The advantage of the use of self-energizing force-generating means is to be seen in the fact that only a small force has to be applied to initiate a braking process. This has, in particular, advantages in the configuration of the connection of the smart or inventive actuator via the energy supply line to the force store which is arranged, for example, on the car side. Furthermore, little energy is consumed during braking. The operating costs are therefore lowered. Finally, the brake can be embodied in a more compact and lightweight fashion than would be the case in brakes without self-energization.

Electrically drivable emergency triggering means are advantageously provided for releasing the brake, and an additional connection which is electrically connected to the emergency triggering means is provided for connecting an external electrical energy supply. By using the emergency triggering means it is possible to release from the outside the brake which is connected to the actuator according to the invention. For this purpose, for example a predefined supply voltage is applied to the additional connection, with the result that the emergency triggering means which comprise, for example, an electric motor and a spindle tension a spring and therefore release the brake.

In a further expedient refinement of the brake system according to the invention, the energy store is an electrical energy store which makes available an electrical supply voltage on the output side. According to this variant of the invention, the energy store is connected to the actuator according to the invention via an electrical connecting line.

The brake system according to the invention expediently has a converter unit which is connected to the brake controller and/or to the actuator, wherein the converter unit has at least one converter which makes available an electrical variable on the output side as a function of a pressure which is fed in on the input side or else of an electrical signal, wherein the converter or converters is/are provided for connection to a signal generator, detecting the state of the supporting spring, of the rail vehicle and/or of at least one pneumatic line of a rail vehicle. According to this expedient development, it is possible to control the brake system via pressure lines, for example via what is referred to as a main air line (HL). The converter unit is expediently connected to the brake controller and/or to the smart actuators via an electrical or optical data line. The conversion of a pneumatic control pressure is carried out using converters which are commercially available and are therefore very well known to a person skilled in the art. There is no need for precise presentation of the method of operation of such converters here. The converters make available, on the output side, an electrical or optical measured variable which corresponds to the pneumatic or hydraulic pressure or signal present on the input side. The converter unit transmits the measured variable acquired in this way to the brake controller via the data line. Of course, it is possible to process the measured value before this. In this context it is also expedient to connect the converter unit to the energy store via an electrical supply line. The energy store makes available the electrical energy which is possibly required by the converter. Furthermore, the converter unit can be arranged as desired and can, for example, also be arranged in the bogie or else on the car side. The supporting spring is embodied, for example, as an air spring, secondary spring, steel spring, flexicoil spring with a rubber additional spring or a hydropneumatic spring. In the case of an air spring, the converter unit communicates with the air spring via a pneumatic line.

The data line is expediently a data bus which connects brake controller, each actuator and each converter unit to one another. Such data buses are best known in the field of industrial control and are configured for the exchange of communications between a plurality of components of a system, with the result that particularly effective and rapid communication is made available, and said communication also satisfies the respective safety requirements.

The actuators are expediently connected to an electrical safety loop for transmitting control signals. The electrical safety loop is already known from the field of pneumatic brakes. It usually serves to trigger an emergency braking instruction, for example as a result of activation of a car-side safety switch. Such activation opens the electrical safety loop, after which the logic unit of the actuator according to the invention ensures rapid braking occurs.

Means for detecting the load state and/or the mass of the rail vehicle which are connected to actuators are advantageously provided, wherein said actuators limit the braking force to be set as a function of the load state and/or the mass. These means for detecting the load state are, for example, the above-mentioned converters of the converter unit. However, within the scope of the invention other sensors are also possible. Each actuator is expediently connected to said means.

According to one advantageous development of the rail vehicle according to the invention, each car of the vehicle train of the rail system has at least one brake system of the type mentioned above. According to one variant, each car has two such brake systems, wherein, for example, each brake system has a converter unit which is respectively connected to an air spring of said car. Of course, each converter unit can also be connected to two air springs of the same car if it is expedient to do so. If only one brake system is provided for each car and if, for example, a converter is part of the brake system according to the invention, said converter is, of course, connected to one or more air springs or else to all of the air springs of a car depending on requirements.

As has already been stated above, a safety loop expediently extends through the entire vehicle train of the rail vehicle. The safety loop is connected to each of the actuators. The safety loop is, for example, a simple wire connection.

Furthermore, according to one preferred refinement, the rail vehicle has a compressed air line, for example a main air line, which extends through all cars and has the purpose of conducting a pneumatic control pressure. The main air line is connected to each converter unit.

A vehicle train data line expediently serves to connect the brake systems of a rail vehicle.

Further expedient refinements and advantages of the invention are the subject matter of the following description of exemplary embodiments of the invention with reference to the figures of the drawing, wherein identical reference symbols refer to identically acting components, and wherein

FIG. 1 shows an exemplary embodiment of the actuator according to the invention in a schematic illustration,

FIGS. 2 to 4 show exemplary embodiments of a brake system according to the invention in a schematic view, and

FIGS. 5 and 6 show a schematic illustration of exemplary embodiments of the rail vehicle according to the invention.

FIG. 1 shows an exemplary embodiment of an actuator 1 according to the invention in a schematic view. The actuator 1 has a logic unit 2 which is connected to a control connection 3 via electrical or optical connecting lines. A supply connection 4, which can be connected to an energy store, serves to supply energy, with the result that a supply voltage drops across the output of the supply connection 4.

Furthermore, the actuator 1 has means for generating a braking movement 5, for example in the form of a self-energizing electrohydraulic brake 5. The self-energizing electrohydraulic brake 5 has an electromechanical force unit (not illustrated figuratively) such as, for example, an electric motor or a pump which is linked to a store and which builds up a hydraulic pressure which triggers the braking and which ensures the generation of a braking movement with a braking force F in a hydraulic brake cylinder which is also part of the self-energizing hydraulic brake 5. The braking force F is applied to a pressing part holder 7 via an expedient lever mechanism 6, which pressing part holder 7 is equipped with a pressing part 8 which is arranged opposite a brake disk 9 of a rail vehicle (not illustrated figuratively). The pressing part 7 in the exemplary embodiment shown is a brake lining. The term actuator also comprises here the brake caliper 7 with its pressing part 8. During travel of the rail vehicle, a rotational movement of the brake disk 9 occurs, said brake disk 9 being connected in a rotationally fixed fashion to a running axle of the rail vehicle. Pressing the pressing part 8 with frictional engagement against the brake disk 9 causes negative acceleration of the rail vehicle to occur and/or a build-up of deceleration force at the wheel.

The actuator 1 also has a braking force detection unit 10 with which an electrical signal which corresponds to the braking force is transmitted to the logic unit.

The self-energizing brake 5 is connected to the supply connection 4 in order to drive the electromechanical force unit, which is an electric motor in the exemplary embodiment shown. This is done by means of an electrical connection, illustrated in FIG. 1 and in the other figures by a continuous line. Pneumatic connections are also represented by dashed lines. The setting of the setpoint value of the actuator 1 is carried out by a superordinate brake controller of the rail vehicle. The brake controller makes available, for each actuator 1, a setpoint value which is transmitted from the brake controller to the control connection 3 and therefore to the logic unit 2. On the basis of the connection between the braking force detection unit 10 and the logic unit 2, the logic unit 2 has both the setpoint value and an actual value. Furthermore, the logic unit 2 is equipped with an implemented or programmed logic which can be used to allow it to control, for example, the self-energizing hydraulic brake 5 in such a way that the actual value corresponds as precisely as possible to the setpoint value. This makes available a smart actuator 1.

With the exception of the lever mechanism 6 and the pressing part holder with pressing part 7, all the components of the actuator 1 according to the invention are arranged in or on a common housing 11. The housing 11 is mounted in a bogie of the rail vehicle (not shown) using expedient attachment means such as, for example, screws or the like. Since brake caliper 7 and the lever mechanism 6 are also arranged in the bogie, all the components of the actuator 1 are configured for mounting in the bogie and correspondingly designed.

FIG. 2 shows an exemplary embodiment of the brake system 12 according to the invention which has a plurality of actuators 1 according to FIG. 1. The number of the actuators 1 is dependent on the respective request. The number of the actuators 1 is therefore represented in a variable fashion by the circles. For example, the brake system 12 comprises two actuators 1 for each axle of the bogie.

Two-axle bogies therefore have four actuators 1.

Furthermore, the brake system 12 comprises a superordinate brake controller 13 and an energy store 14. The brake controller 13 is connected via an electrical data line, what is referred to as a data bus 15, to the smart actuators 1 which are assigned thereto. The data bus 15 is, for example, an industrial bus system which is known to a person skilled in the art, with the result that there is no need to go into details on this here. It is to be noted that the data bus 15 permits both an exchange of information between the brake controller 13 and the actuators 1 as well as among the actuators 1 themselves. The energy store 14 is connected via electrical supply lines 16 to the supply connection 4, see FIG. 1, of each actuator 1. Said energy store 14 serves to make available at least part of the energy necessary to brake and release the brake.

FIG. 3 shows a further exemplary embodiment of the brake system 12 according to the invention as in FIG. 2, wherein, however, in contrast to the exemplary embodiment shown in FIG. 2 a converter unit 17 is provided which can be used to take into account the load state of the car of the rail vehicle to be braked or of the entire rail vehicle during braking. For this purpose, the converter unit 17 is connected via a pneumatic interface 18 to an air spring 19. It is to be noted here that a car body 20 of the rail vehicle is mounted by means of the air spring 19 on a bogie (not illustrated) of the rail vehicle. Depending on the load state, the air spring is therefore compressed to differing degrees, with the result that the air pressure prevailing in the air spring 19 is a measure of the load state of the car 20. In rail vehicles without a pneumatic secondary spring, the load signal can also be an electrical variable. The converter unit 17 has a converter (not shown figuratively) to which the pressure of the air spring 10 is applied on the input side. On the output side, the converter makes available a current signal which corresponds to the pressure of the air spring 19. The converter unit 17 also has means for processing measured values, which means sample the current signal. The sampled values acquired in the process are digitized by an analog/digital unit. The digital current signal is subsequently converted into a laden weight by a calculation unit of the converter unit 17, said laden weight constituting a measure of the load state. The laden weight is subsequently transmitted via the data bus 15 to the superordinate brake controller 13 and the smart actuators 1. It is apparent that in FIG. 3 the superordinate brake controller 13 is represented by two separate units 13. This is intended to clarify that the brake controller 13 is of redundant design, with the result that in the case of failure of a brake controller 13 a second brake controller 13 permits reliable braking. Of course, it is also possible to distribute the components of a brake controller between two housings which are arranged separately. In FIG. 3, the two brake controllers 13 exchange data with the actuators 1 and the converter unit 17 via the data bus 15. The brake controllers 13 determine, on the basis of the transferred load state, setpoint values which are then transmitted to the actuators.

The exemplary embodiment according to FIG. 4 corresponds very largely to the exemplary embodiment shown in FIG. 3, wherein the pressure of a pneumatic main air line 21 is additionally applied on the input side to the converter unit 17 in the exemplary embodiment according to FIG. 4. For this purpose, the main air line 21 is pneumatically connected via a connecting line 22 to the converter unit 17. The converter unit 17 according to FIG. 4 therefore has two converters, which each make available an electrical signal as a function of the pressure of the main air line or of the air spring 19. In this way, a desired braking deceleration can be predefined to the brake system 12 according to FIG. 4 via the main air line. The converter unit 17 converts the pressure of the main air line 21 into a corresponding electrical and, for example, digital signal and makes this available to the brake controller 13 via the data bus 15, which transmits a setpoint value corresponding to the pressure of the main air line 21 or a corresponding control signal to the actuators 1. Said actuators 1 then generate, on the basis of their internal logic, an actual value which corresponds very largely to the setpoint value.

FIG. 5 is a schematic view of a car 23 (illustrated by a dotted line) of a rail vehicle, which car 23 has two brake systems 12 according to FIG. 4. The brake systems 12 are connected to one another via a vehicle data line 24, also a data bus. To be more precise, the superordinate brake controllers 13 of each brake system 12 are connected to the vehicle data bus 24. The brake controllers 13 have an interface which is expedient for this purpose. A braking instruction, for example from the driver of the vehicle, can be transferred via the vehicle data line 24 to the individual brake controllers 13 of the car 23. Each brake controller 13 is connected via the corresponding converter unit 17 to an air spring 19 which is assigned thereto, and said brake controller 13 generates, on the basis of the payload which is known to it and as a function of the central braking instruction, setpoint values for the smart actuators 1 which are assigned to it. In this context there is no need at all for all the actuators 1 which are assigned to the brake controller 13 to receive the same setpoint value. Within the scope of the invention it is perfectly possible for the brake controller 13 to transmit different braking setpoint values to each actuator 1 which is assigned to it. Furthermore, the setpoint values of the other brake controllers 13 can differ from one another for example owing to a differing pressure in the respective air spring 19.

In addition it is apparent that the actuators 1 are connected to one another via an electrical safety loop 25. Such an electrical safety loop 25 is already current practice in pneumatic brakes. If the electrical connection of this safety loop 25 is interrupted, each smart actuator 1 initiates an emergency braking operation which is independent of the service brake. Such an emergency braking operation is triggered, for example, by pressing a car-side emergency braking button. According to the inventive solution, such an emergency braking operation is set by the actuators 1 with a maximum braking force, wherein the maximum value of the braking force is calculated as a function of the payload information from the converter unit 17. If such an emergency braking operation occurs when communication between the converter unit 17 and the actuator 1 is disrupted, the actuator 1 sets an equivalent value for limiting the braking force.

FIG. 6 shows a further exemplary embodiment of a rail vehicle according to the invention in which two cars 23 are illustrated, said cars being each represented by a dotted line. It is apparent that each car 23 has a brake system 12, wherein the converter unit 17 of each brake system 12 is pneumatically connected to two air springs 19. The measured pressure values, detected by the converter units 17, of the air springs 19 are transmitted to the superordinate brake controller 13 and the actuators 1, which calculates all the setpoint values for the car 23 and sends them to the actuators 1 via the data bus 12. Furthermore, the converter unit 17 is connected to the main air line 21 which extends through the entire train of cars. The same applies to the safety loop 25, which reconnects all the actuators 1 of all the brake systems 12 to one another. The brake controller 13 of each brake system 12 of a car is again connected via a vehicle data bus 24 to the rest of the brake controllers 18 of the rail vehicle. What has been stated in relation to FIG. 5 also applies.

In conclusion it is to be noted that the converter unit 17 within the scope of the invention does not have to be embodied as a separate component with a separate housing, as illustrated in the figures. Instead, within the scope of the invention it is also possible to configure the converter unit 17 as part of the brake controller. The converter unit 17 is therefore accommodated in the housing of the respective assigned brake controller. In order to supply them with energy, all the components of the brake system, in particular also the converter unit, can be connected to the energy storage unit 14 within the scope of the invention. The energy storage unit can also be the vehicle on-board power system.